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Merge branches 'for-4.2/i2c-hid', 'for-4.2/lenovo', 'for-4.2/plantronics', 'for-4.2/rmi', 'for-4.2/sensor-hub', 'for-4.2/sjoy', 'for-4.2/sony' and 'for-4.2/wacom' into for-linus 

Conflicts:
	drivers/hid/wacom_wac.c
hifive-unleashed-5.1
Jiri Kosina 2015-06-22 16:23:43 +02:00
parent 817a312581 3e48138c2c 181a8b911d 81bb773fae 10e87dc42a 30ee72f0d2 6e5e9a06a2 b2723eb73c 2a6cdbdd4c
commit ec3b34e197
8015 changed files with 333542 additions and 173658 deletions
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1
.gitignore vendored
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@ -24,6 +24,7 @@
*.order
*.elf
*.bin
*.tar
*.gz
*.bz2
*.lzma

1
.mailmap
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@ -100,6 +100,7 @@ Rajesh Shah <rajesh.shah@intel.com>
Ralf Baechle <ralf@linux-mips.org>
Ralf Wildenhues <Ralf.Wildenhues@gmx.de>
Rémi Denis-Courmont <rdenis@simphalempin.com>
Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Rudolf Marek <R.Marek@sh.cvut.cz>
Rui Saraiva <rmps@joel.ist.utl.pt>
Sachin P Sant <ssant@in.ibm.com>

28
CREDITS
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@ -508,6 +508,10 @@ E: paul@paulbristow.net
W: http://paulbristow.net/linux/idefloppy.html
D: Maintainer of IDE/ATAPI floppy driver
N: Stefano Brivio
E: stefano.brivio@polimi.it
D: Broadcom B43 driver
N: Dominik Brodowski
E: linux@brodo.de
W: http://www.brodo.de/
@ -2045,6 +2049,10 @@ D: pirq addr, CS5535 alsa audio driver
S: Gurgaon, India
S: Kuala Lumpur, Malaysia
N: Mohit Kumar
D: ST Microelectronics SPEAr13xx PCI host bridge driver
D: Synopsys Designware PCI host bridge driver
N: Gabor Kuti
M: seasons@falcon.sch.bme.hu
M: seasons@makosteszta.sote.hu
@ -3008,6 +3016,19 @@ W: http://www.qsl.net/dl1bke/
D: Generic Z8530 driver, AX.25 DAMA slave implementation
D: Several AX.25 hacks
N: Ricardo Ribalda Delgado
E: ricardo.ribalda@gmail.com
W: http://ribalda.com
D: PLX USB338x driver
D: PCA9634 driver
D: Option GTM671WFS
D: Fintek F81216A
D: Various kernel hacks
S: Qtechnology A/S
S: Valby Langgade 142
S: 2500 Valby
S: Denmark
N: Francois-Rene Rideau
E: fare@tunes.org
W: http://www.tunes.org/~fare
@ -3688,6 +3709,13 @@ N: Dirk Verworner
D: Co-author of German book ``Linux-Kernel-Programmierung''
D: Co-founder of Berlin Linux User Group
N: Andrew Victor
E: linux@maxim.org.za
W: http://maxim.org.za/at91_26.html
D: First maintainer of Atmel ARM-based SoC, aka AT91
D: Introduced support for at91rm9200, the first chip of AT91 family
S: South Africa
N: Riku Voipio
E: riku.voipio@iki.fi
D: Author of PCA9532 LED and Fintek f75375s hwmon driver

119
Documentation/ABI/obsolete/sysfs-block-zram 100644
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@ -0,0 +1,119 @@
What: /sys/block/zram<id>/num_reads
Date: August 2015
Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Description:
The num_reads file is read-only and specifies the number of
reads (failed or successful) done on this device.
Now accessible via zram<id>/stat node.
What: /sys/block/zram<id>/num_writes
Date: August 2015
Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Description:
The num_writes file is read-only and specifies the number of
writes (failed or successful) done on this device.
Now accessible via zram<id>/stat node.
What: /sys/block/zram<id>/invalid_io
Date: August 2015
Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Description:
The invalid_io file is read-only and specifies the number of
non-page-size-aligned I/O requests issued to this device.
Now accessible via zram<id>/io_stat node.
What: /sys/block/zram<id>/failed_reads
Date: August 2015
Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Description:
The failed_reads file is read-only and specifies the number of
failed reads happened on this device.
Now accessible via zram<id>/io_stat node.
What: /sys/block/zram<id>/failed_writes
Date: August 2015
Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Description:
The failed_writes file is read-only and specifies the number of
failed writes happened on this device.
Now accessible via zram<id>/io_stat node.
What: /sys/block/zram<id>/notify_free
Date: August 2015
Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Description:
The notify_free file is read-only. Depending on device usage
scenario it may account a) the number of pages freed because
of swap slot free notifications or b) the number of pages freed
because of REQ_DISCARD requests sent by bio. The former ones
are sent to a swap block device when a swap slot is freed, which
implies that this disk is being used as a swap disk. The latter
ones are sent by filesystem mounted with discard option,
whenever some data blocks are getting discarded.
Now accessible via zram<id>/io_stat node.
What: /sys/block/zram<id>/zero_pages
Date: August 2015
Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Description:
The zero_pages file is read-only and specifies number of zero
filled pages written to this disk. No memory is allocated for
such pages.
Now accessible via zram<id>/mm_stat node.
What: /sys/block/zram<id>/orig_data_size
Date: August 2015
Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Description:
The orig_data_size file is read-only and specifies uncompressed
size of data stored in this disk. This excludes zero-filled
pages (zero_pages) since no memory is allocated for them.
Unit: bytes
Now accessible via zram<id>/mm_stat node.
What: /sys/block/zram<id>/compr_data_size
Date: August 2015
Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Description:
The compr_data_size file is read-only and specifies compressed
size of data stored in this disk. So, compression ratio can be
calculated using orig_data_size and this statistic.
Unit: bytes
Now accessible via zram<id>/mm_stat node.
What: /sys/block/zram<id>/mem_used_total
Date: August 2015
Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Description:
The mem_used_total file is read-only and specifies the amount
of memory, including allocator fragmentation and metadata
overhead, allocated for this disk. So, allocator space
efficiency can be calculated using compr_data_size and this
statistic.
Unit: bytes
Now accessible via zram<id>/mm_stat node.
What: /sys/block/zram<id>/mem_used_max
Date: August 2015
Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Description:
The mem_used_max file is read/write and specifies the amount
of maximum memory zram have consumed to store compressed data.
For resetting the value, you should write "0". Otherwise,
you could see -EINVAL.
Unit: bytes
Downgraded to write-only node: so it's possible to set new
value only; its current value is stored in zram<id>/mm_stat
node.
What: /sys/block/zram<id>/mem_limit
Date: August 2015
Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Description:
The mem_limit file is read/write and specifies the maximum
amount of memory ZRAM can use to store the compressed data.
The limit could be changed in run time and "0" means disable
the limit. No limit is the initial state. Unit: bytes
Downgraded to write-only node: so it's possible to set new
value only; its current value is stored in zram<id>/mm_stat
node.

22
Documentation/ABI/testing/sysfs-block-dm
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@ -23,3 +23,25 @@ Description: Device-mapper device suspend state.
Contains the value 1 while the device is suspended.
Otherwise it contains 0. Read-only attribute.
Users: util-linux, device-mapper udev rules
What: /sys/block/dm-<num>/dm/rq_based_seq_io_merge_deadline
Date: March 2015
KernelVersion: 4.1
Contact: dm-devel@redhat.com
Description: Allow control over how long a request that is a
reasonable merge candidate can be queued on the request
queue. The resolution of this deadline is in
microseconds (ranging from 1 to 100000 usecs).
Setting this attribute to 0 (the default) will disable
request-based DM's merge heuristic and associated extra
accounting. This attribute is not applicable to
bio-based DM devices so it will only ever report 0 for
them.
What: /sys/block/dm-<num>/dm/use_blk_mq
Date: March 2015
KernelVersion: 4.1
Contact: dm-devel@redhat.com
Description: Request-based Device-mapper blk-mq I/O path mode.
Contains the value 1 if the device is using blk-mq.
Otherwise it contains 0. Read-only attribute.

25
Documentation/ABI/testing/sysfs-block-zram
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@ -141,3 +141,28 @@ Description:
amount of memory ZRAM can use to store the compressed data. The
limit could be changed in run time and "0" means disable the
limit. No limit is the initial state. Unit: bytes
What: /sys/block/zram<id>/compact
Date: August 2015
Contact: Minchan Kim <minchan@kernel.org>
Description:
The compact file is write-only and trigger compaction for
allocator zrm uses. The allocator moves some objects so that
it could free fragment space.
What: /sys/block/zram<id>/io_stat
Date: August 2015
Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Description:
The io_stat file is read-only and accumulates device's I/O
statistics not accounted by block layer. For example,
failed_reads, failed_writes, etc. File format is similar to
block layer statistics file format.
What: /sys/block/zram<id>/mm_stat
Date: August 2015
Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Description:
The mm_stat file is read-only and represents device's mm
statistics (orig_data_size, compr_data_size, etc.) in a format
similar to block layer statistics file format.

2
Documentation/ABI/testing/sysfs-class-cxl
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@ -100,7 +100,7 @@ Description: read only
Hexadecimal value of the device ID found in this AFU
configuration record.
What: /sys/class/cxl/<afu>/cr<config num>/vendor
What: /sys/class/cxl/<afu>/cr<config num>/class
Date: February 2015
Contact: linuxppc-dev@lists.ozlabs.org
Description: read only

80
Documentation/ABI/testing/sysfs-class-led-flash 100644
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@ -0,0 +1,80 @@
What: /sys/class/leds/<led>/flash_brightness
Date: March 2015
KernelVersion: 4.0
Contact: Jacek Anaszewski <j.anaszewski@samsung.com>
Description: read/write
Set the brightness of this LED in the flash strobe mode, in
microamperes. The file is created only for the flash LED devices
that support setting flash brightness.
The value is between 0 and
/sys/class/leds/<led>/max_flash_brightness.
What: /sys/class/leds/<led>/max_flash_brightness
Date: March 2015
KernelVersion: 4.0
Contact: Jacek Anaszewski <j.anaszewski@samsung.com>
Description: read only
Maximum brightness level for this LED in the flash strobe mode,
in microamperes.
What: /sys/class/leds/<led>/flash_timeout
Date: March 2015
KernelVersion: 4.0
Contact: Jacek Anaszewski <j.anaszewski@samsung.com>
Description: read/write
Hardware timeout for flash, in microseconds. The flash strobe
is stopped after this period of time has passed from the start
of the strobe. The file is created only for the flash LED
devices that support setting flash timeout.
What: /sys/class/leds/<led>/max_flash_timeout
Date: March 2015
KernelVersion: 4.0
Contact: Jacek Anaszewski <j.anaszewski@samsung.com>
Description: read only
Maximum flash timeout for this LED, in microseconds.
What: /sys/class/leds/<led>/flash_strobe
Date: March 2015
KernelVersion: 4.0
Contact: Jacek Anaszewski <j.anaszewski@samsung.com>
Description: read/write
Flash strobe state. When written with 1 it triggers flash strobe
and when written with 0 it turns the flash off.
On read 1 means that flash is currently strobing and 0 means
that flash is off.
What: /sys/class/leds/<led>/flash_fault
Date: March 2015
KernelVersion: 4.0
Contact: Jacek Anaszewski <j.anaszewski@samsung.com>
Description: read only
Space separated list of flash faults that may have occurred.
Flash faults are re-read after strobing the flash. Possible
flash faults:
* led-over-voltage - flash controller voltage to the flash LED
has exceeded the limit specific to the flash controller
* flash-timeout-exceeded - the flash strobe was still on when
the timeout set by the user has expired; not all flash
controllers may set this in all such conditions
* controller-over-temperature - the flash controller has
overheated
* controller-short-circuit - the short circuit protection
of the flash controller has been triggered
* led-power-supply-over-current - current in the LED power
supply has exceeded the limit specific to the flash
controller
* indicator-led-fault - the flash controller has detected
a short or open circuit condition on the indicator LED
* led-under-voltage - flash controller voltage to the flash
LED has been below the minimum limit specific to
the flash
* controller-under-voltage - the input voltage of the flash
controller is below the limit under which strobing the
flash at full current will not be possible;
the condition persists until this flag is no longer set
* led-over-temperature - the temperature of the LED has exceeded
its allowed upper limit

10
Documentation/ABI/testing/sysfs-class-mtd
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@ -222,3 +222,13 @@ Description:
The number of blocks that are marked as reserved, if any, in
this partition. These are typically used to store the in-flash
bad block table (BBT).
What: /sys/class/mtd/mtdX/offset
Date: March 2015
KernelVersion: 4.1
Contact: linux-mtd@lists.infradead.org
Description:
For a partition, the offset of that partition from the start
of the master device in bytes. This attribute is absent on
main devices, so it can be used to distinguish between
partitions and devices that aren't partitions.

8
Documentation/ABI/testing/sysfs-class-net
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@ -188,6 +188,14 @@ Description:
Indicates the interface unique physical port identifier within
the NIC, as a string.
What: /sys/class/net/<iface>/phys_port_name
Date: March 2015
KernelVersion: 4.0
Contact: netdev@vger.kernel.org
Description:
Indicates the interface physical port name within the NIC,
as a string.
What: /sys/class/net/<iface>/speed
Date: October 2009
KernelVersion: 2.6.33

8
Documentation/ABI/testing/sysfs-class-net-queues
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@ -24,6 +24,14 @@ Description:
Indicates the number of transmit timeout events seen by this
network interface transmit queue.
What: /sys/class/<iface>/queues/tx-<queue>/tx_maxrate
Date: March 2015
KernelVersion: 4.1
Contact: netdev@vger.kernel.org
Description:
A Mbps max-rate set for the queue, a value of zero means disabled,
default is disabled.
What: /sys/class/<iface>/queues/tx-<queue>/xps_cpus
Date: November 2010
KernelVersion: 2.6.38

93
Documentation/ABI/testing/sysfs-driver-toshiba_acpi
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@ -8,9 +8,11 @@ Description: This file controls the keyboard backlight operation mode, valid
* 0x2 -> AUTO (also called TIMER)
* 0x8 -> ON
* 0x10 -> OFF
Note that the kernel 3.16 onwards this file accepts all listed
Note that from kernel 3.16 onwards this file accepts all listed
parameters, kernel 3.15 only accepts the first two (FN-Z and
AUTO).
Also note that toggling this value on type 1 devices, requires
a reboot for changes to take effect.
Users: KToshiba
What: /sys/devices/LNXSYSTM:00/LNXSYBUS:00/TOS{1900,620{0,7,8}}:00/kbd_backlight_timeout
@ -67,15 +69,72 @@ Description: This file shows the current keyboard backlight type,
* 2 -> Type 2, supporting modes TIMER, ON and OFF
Users: KToshiba
What: /sys/devices/LNXSYSTM:00/LNXSYBUS:00/TOS{1900,620{0,7,8}}:00/usb_sleep_charge
Date: January 23, 2015
KernelVersion: 4.0
Contact: Azael Avalos <coproscefalo@gmail.com>
Description: This file controls the USB Sleep & Charge charging mode, which
can be:
* 0 -> Disabled (0x00)
* 1 -> Alternate (0x09)
* 2 -> Auto (0x21)
* 3 -> Typical (0x11)
Note that from kernel 4.1 onwards this file accepts all listed
values, kernel 4.0 only supports the first three.
Note that this feature only works when connected to power, if
you want to use it under battery, see the entry named
"sleep_functions_on_battery"
Users: KToshiba
What: /sys/devices/LNXSYSTM:00/LNXSYBUS:00/TOS{1900,620{0,7,8}}:00/sleep_functions_on_battery
Date: January 23, 2015
KernelVersion: 4.0
Contact: Azael Avalos <coproscefalo@gmail.com>
Description: This file controls the USB Sleep Functions under battery, and
set the level at which point they will be disabled, accepted
values can be:
* 0 -> Disabled
* 1-100 -> Battery level to disable sleep functions
Currently it prints two values, the first one indicates if the
feature is enabled or disabled, while the second one shows the
current battery level set.
Note that when the value is set to disabled, the sleep function
will only work when connected to power.
Users: KToshiba
What: /sys/devices/LNXSYSTM:00/LNXSYBUS:00/TOS{1900,620{0,7,8}}:00/usb_rapid_charge
Date: January 23, 2015
KernelVersion: 4.0
Contact: Azael Avalos <coproscefalo@gmail.com>
Description: This file controls the USB Rapid Charge state, which can be:
* 0 -> Disabled
* 1 -> Enabled
Note that toggling this value requires a reboot for changes to
take effect.
Users: KToshiba
What: /sys/devices/LNXSYSTM:00/LNXSYBUS:00/TOS{1900,620{0,7,8}}:00/usb_sleep_music
Date: January 23, 2015
KernelVersion: 4.0
Contact: Azael Avalos <coproscefalo@gmail.com>
Description: This file controls the Sleep & Music state, which values can be:
* 0 -> Disabled
* 1 -> Enabled
Note that this feature only works when connected to power, if
you want to use it under battery, see the entry named
"sleep_functions_on_battery"
Users: KToshiba
What: /sys/devices/LNXSYSTM:00/LNXSYBUS:00/TOS{1900,620{0,7,8}}:00/version
Date: February, 2015
KernelVersion: 3.20
Date: February 12, 2015
KernelVersion: 4.0
Contact: Azael Avalos <coproscefalo@gmail.com>
Description: This file shows the current version of the driver
Users: KToshiba
What: /sys/devices/LNXSYSTM:00/LNXSYBUS:00/TOS{1900,620{0,7,8}}:00/fan
Date: February, 2015
KernelVersion: 3.20
Date: February 12, 2015
KernelVersion: 4.0
Contact: Azael Avalos <coproscefalo@gmail.com>
Description: This file controls the state of the internal fan, valid
values are:
@ -83,8 +142,8 @@ Description: This file controls the state of the internal fan, valid
* 1 -> ON
What: /sys/devices/LNXSYSTM:00/LNXSYBUS:00/TOS{1900,620{0,7,8}}:00/kbd_function_keys
Date: February, 2015
KernelVersion: 3.20
Date: February 12, 2015
KernelVersion: 4.0
Contact: Azael Avalos <coproscefalo@gmail.com>
Description: This file controls the Special Functions (hotkeys) operation
mode, valid values are:
@ -94,21 +153,29 @@ Description: This file controls the Special Functions (hotkeys) operation
and the hotkeys are accessed via FN-F{1-12}.
In the "Special Functions" mode, the F{1-12} keys trigger the
hotkey and the F{1-12} keys are accessed via FN-F{1-12}.
Note that toggling this value requires a reboot for changes to
take effect.
Users: KToshiba
What: /sys/devices/LNXSYSTM:00/LNXSYBUS:00/TOS{1900,620{0,7,8}}:00/panel_power_on
Date: February, 2015
KernelVersion: 3.20
Date: February 12, 2015
KernelVersion: 4.0
Contact: Azael Avalos <coproscefalo@gmail.com>
Description: This file controls whether the laptop should turn ON whenever
the LID is opened, valid values are:
* 0 -> Disabled
* 1 -> Enabled
Note that toggling this value requires a reboot for changes to
take effect.
Users: KToshiba
What: /sys/devices/LNXSYSTM:00/LNXSYBUS:00/TOS{1900,620{0,7,8}}:00/usb_three
Date: February, 2015
KernelVersion: 3.20
Date: February 12, 2015
KernelVersion: 4.0
Contact: Azael Avalos <coproscefalo@gmail.com>
Description: This file controls whether the USB 3 functionality, valid
values are:
Description: This file controls the USB 3 functionality, valid values are:
* 0 -> Disabled (Acts as a regular USB 2)
* 1 -> Enabled (Full USB 3 functionality)
Note that toggling this value requires a reboot for changes to
take effect.
Users: KToshiba

69
Documentation/ABI/testing/sysfs-platform-dell-laptop 100644
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@ -0,0 +1,69 @@
What: /sys/class/leds/dell::kbd_backlight/als_enabled
Date: December 2014
KernelVersion: 3.19
Contact: Gabriele Mazzotta <gabriele.mzt@gmail.com>,
Pali Rohár <pali.rohar@gmail.com>
Description:
This file allows to control the automatic keyboard
illumination mode on some systems that have an ambient
light sensor. Write 1 to this file to enable the auto
mode, 0 to disable it.
What: /sys/class/leds/dell::kbd_backlight/als_setting
Date: December 2014
KernelVersion: 3.19
Contact: Gabriele Mazzotta <gabriele.mzt@gmail.com>,
Pali Rohár <pali.rohar@gmail.com>
Description:
This file allows to specifiy the on/off threshold value,
as reported by the ambient light sensor.
What: /sys/class/leds/dell::kbd_backlight/start_triggers
Date: December 2014
KernelVersion: 3.19
Contact: Gabriele Mazzotta <gabriele.mzt@gmail.com>,
Pali Rohár <pali.rohar@gmail.com>
Description:
This file allows to control the input triggers that
turn on the keyboard backlight illumination that is
disabled because of inactivity.
Read the file to see the triggers available. The ones
enabled are preceded by '+', those disabled by '-'.
To enable a trigger, write its name preceded by '+' to
this file. To disable a trigger, write its name preceded
by '-' instead.
For example, to enable the keyboard as trigger run:
echo +keyboard > /sys/class/leds/dell::kbd_backlight/start_triggers
To disable it:
echo -keyboard > /sys/class/leds/dell::kbd_backlight/start_triggers
Note that not all the available triggers can be configured.
What: /sys/class/leds/dell::kbd_backlight/stop_timeout
Date: December 2014
KernelVersion: 3.19
Contact: Gabriele Mazzotta <gabriele.mzt@gmail.com>,
Pali Rohár <pali.rohar@gmail.com>
Description:
This file allows to specify the interval after which the
keyboard illumination is disabled because of inactivity.
The timeouts are expressed in seconds, minutes, hours and
days, for which the symbols are 's', 'm', 'h' and 'd'
respectively.
To configure the timeout, write to this file a value along
with any the above units. If no unit is specified, the value
is assumed to be expressed in seconds.
For example, to set the timeout to 10 minutes run:
echo 10m > /sys/class/leds/dell::kbd_backlight/stop_timeout
Note that when this file is read, the returned value might be
expressed in a different unit than the one used when the timeout
was set.
Also note that only some timeouts are supported and that
some systems might fall back to a specific timeout in case
an invalid timeout is written to this file.

158
Documentation/CodingStyle
View File

@ -13,7 +13,7 @@ and NOT read it. Burn them, it's a great symbolic gesture.
Anyway, here goes:
Chapter 1: Indentation
Chapter 1: Indentation
Tabs are 8 characters, and thus indentations are also 8 characters.
There are heretic movements that try to make indentations 4 (or even 2!)
@ -56,7 +56,6 @@ instead of "double-indenting" the "case" labels. E.g.:
break;
}
Don't put multiple statements on a single line unless you have
something to hide:
@ -156,25 +155,25 @@ comments on.
Do not unnecessarily use braces where a single statement will do.
if (condition)
action();
if (condition)
action();
and
if (condition)
do_this();
else
do_that();
if (condition)
do_this();
else
do_that();
This does not apply if only one branch of a conditional statement is a single
statement; in the latter case use braces in both branches:
if (condition) {
do_this();
do_that();
} else {
otherwise();
}
if (condition) {
do_this();
do_that();
} else {
otherwise();
}
3.1: Spaces
@ -186,8 +185,11 @@ although they are not required in the language, as in: "sizeof info" after
"struct fileinfo info;" is declared).
So use a space after these keywords:
if, switch, case, for, do, while
but not with sizeof, typeof, alignof, or __attribute__. E.g.,
s = sizeof(struct file);
Do not add spaces around (inside) parenthesized expressions. This example is
@ -209,12 +211,15 @@ such as any of these:
= + - < > * / % | & ^ <= >= == != ? :
but no space after unary operators:
& * + - ~ ! sizeof typeof alignof __attribute__ defined
no space before the postfix increment & decrement unary operators:
++ --
no space after the prefix increment & decrement unary operators:
++ --
and no space around the '.' and "->" structure member operators.
@ -268,13 +273,11 @@ See chapter 6 (Functions).
Chapter 5: Typedefs
Please don't use things like "vps_t".
It's a _mistake_ to use typedef for structures and pointers. When you see a
vps_t a;
in the source, what does it mean?
In contrast, if it says
struct virtual_container *a;
@ -372,11 +375,11 @@ In source files, separate functions with one blank line. If the function is
exported, the EXPORT* macro for it should follow immediately after the closing
function brace line. E.g.:
int system_is_up(void)
{
return system_state == SYSTEM_RUNNING;
}
EXPORT_SYMBOL(system_is_up);
int system_is_up(void)
{
return system_state == SYSTEM_RUNNING;
}
EXPORT_SYMBOL(system_is_up);
In function prototypes, include parameter names with their data types.
Although this is not required by the C language, it is preferred in Linux
@ -405,34 +408,34 @@ The rationale for using gotos is:
modifications are prevented
- saves the compiler work to optimize redundant code away ;)
int fun(int a)
{
int result = 0;
char *buffer;
int fun(int a)
{
int result = 0;
char *buffer;
buffer = kmalloc(SIZE, GFP_KERNEL);
if (!buffer)
return -ENOMEM;
buffer = kmalloc(SIZE, GFP_KERNEL);
if (!buffer)
return -ENOMEM;
if (condition1) {
while (loop1) {
...
if (condition1) {
while (loop1) {
...
}
result = 1;
goto out_buffer;
}
result = 1;
goto out_buffer;
...
out_buffer:
kfree(buffer);
return result;
}
...
out_buffer:
kfree(buffer);
return result;
}
A common type of bug to be aware of it "one err bugs" which look like this:
err:
kfree(foo->bar);
kfree(foo);
return ret;
err:
kfree(foo->bar);
kfree(foo);
return ret;
The bug in this code is that on some exit paths "foo" is NULL. Normally the
fix for this is to split it up into two error labels "err_bar:" and "err_foo:".
@ -503,9 +506,9 @@ values. To do the latter, you can stick the following in your .emacs file:
(defun c-lineup-arglist-tabs-only (ignored)
"Line up argument lists by tabs, not spaces"
(let* ((anchor (c-langelem-pos c-syntactic-element))
(column (c-langelem-2nd-pos c-syntactic-element))
(offset (- (1+ column) anchor))
(steps (floor offset c-basic-offset)))
(column (c-langelem-2nd-pos c-syntactic-element))
(offset (- (1+ column) anchor))
(steps (floor offset c-basic-offset)))
(* (max steps 1)
c-basic-offset)))
@ -612,7 +615,7 @@ have a reference count on it, you almost certainly have a bug.
Names of macros defining constants and labels in enums are capitalized.
#define CONSTANT 0x12345
#define CONSTANT 0x12345
Enums are preferred when defining several related constants.
@ -623,28 +626,28 @@ Generally, inline functions are preferable to macros resembling functions.
Macros with multiple statements should be enclosed in a do - while block:
#define macrofun(a, b, c) \
do { \
if (a == 5) \
do_this(b, c); \
} while (0)
#define macrofun(a, b, c) \
do { \
if (a == 5) \
do_this(b, c); \
} while (0)
Things to avoid when using macros:
1) macros that affect control flow:
#define FOO(x) \
do { \
if (blah(x) < 0) \
return -EBUGGERED; \
} while(0)
#define FOO(x) \
do { \
if (blah(x) < 0) \
return -EBUGGERED; \
} while(0)
is a _very_ bad idea. It looks like a function call but exits the "calling"
function; don't break the internal parsers of those who will read the code.
2) macros that depend on having a local variable with a magic name:
#define FOO(val) bar(index, val)
#define FOO(val) bar(index, val)
might look like a good thing, but it's confusing as hell when one reads the
code and it's prone to breakage from seemingly innocent changes.
@ -656,8 +659,21 @@ bite you if somebody e.g. turns FOO into an inline function.
must enclose the expression in parentheses. Beware of similar issues with
macros using parameters.
#define CONSTANT 0x4000
#define CONSTEXP (CONSTANT | 3)
#define CONSTANT 0x4000
#define CONSTEXP (CONSTANT | 3)
5) namespace collisions when defining local variables in macros resembling
functions:
#define FOO(x) \
({ \
typeof(x) ret; \
ret = calc_ret(x); \
(ret); \
)}
ret is a common name for a local variable - __foo_ret is less likely
to collide with an existing variable.
The cpp manual deals with macros exhaustively. The gcc internals manual also
covers RTL which is used frequently with assembly language in the kernel.
@ -796,11 +812,11 @@ you should use, rather than explicitly coding some variant of them yourself.
For example, if you need to calculate the length of an array, take advantage
of the macro
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
Similarly, if you need to calculate the size of some structure member, use
#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
There are also min() and max() macros that do strict type checking if you
need them. Feel free to peruse that header file to see what else is already
@ -813,19 +829,19 @@ Some editors can interpret configuration information embedded in source files,
indicated with special markers. For example, emacs interprets lines marked
like this:
-*- mode: c -*-
-*- mode: c -*-
Or like this:
/*
Local Variables:
compile-command: "gcc -DMAGIC_DEBUG_FLAG foo.c"
End:
*/
/*
Local Variables:
compile-command: "gcc -DMAGIC_DEBUG_FLAG foo.c"
End:
*/
Vim interprets markers that look like this:
/* vim:set sw=8 noet */
/* vim:set sw=8 noet */
Do not include any of these in source files. People have their own personal
editor configurations, and your source files should not override them. This
@ -902,9 +918,9 @@ At the end of any non-trivial #if or #ifdef block (more than a few lines),
place a comment after the #endif on the same line, noting the conditional
expression used. For instance:
#ifdef CONFIG_SOMETHING
...
#endif /* CONFIG_SOMETHING */
#ifdef CONFIG_SOMETHING
...
#endif /* CONFIG_SOMETHING */
Appendix I: References

860
Documentation/DocBook/crypto-API.tmpl
View File

@ -509,6 +509,270 @@
select it due to the used type and mask field.
</para>
</sect1>
<sect1><title>Internal Structure of Kernel Crypto API</title>
<para>
The kernel crypto API has an internal structure where a cipher
implementation may use many layers and indirections. This section
shall help to clarify how the kernel crypto API uses
various components to implement the complete cipher.
</para>
<para>
The following subsections explain the internal structure based
on existing cipher implementations. The first section addresses
the most complex scenario where all other scenarios form a logical
subset.
</para>
<sect2><title>Generic AEAD Cipher Structure</title>
<para>
The following ASCII art decomposes the kernel crypto API layers
when using the AEAD cipher with the automated IV generation. The
shown example is used by the IPSEC layer.
</para>
<para>
For other use cases of AEAD ciphers, the ASCII art applies as
well, but the caller may not use the GIVCIPHER interface. In
this case, the caller must generate the IV.
</para>
<para>
The depicted example decomposes the AEAD cipher of GCM(AES) based
on the generic C implementations (gcm.c, aes-generic.c, ctr.c,
ghash-generic.c, seqiv.c). The generic implementation serves as an
example showing the complete logic of the kernel crypto API.
</para>
<para>
It is possible that some streamlined cipher implementations (like
AES-NI) provide implementations merging aspects which in the view
of the kernel crypto API cannot be decomposed into layers any more.
In case of the AES-NI implementation, the CTR mode, the GHASH
implementation and the AES cipher are all merged into one cipher
implementation registered with the kernel crypto API. In this case,
the concept described by the following ASCII art applies too. However,
the decomposition of GCM into the individual sub-components
by the kernel crypto API is not done any more.
</para>
<para>
Each block in the following ASCII art is an independent cipher
instance obtained from the kernel crypto API. Each block
is accessed by the caller or by other blocks using the API functions
defined by the kernel crypto API for the cipher implementation type.
</para>
<para>
The blocks below indicate the cipher type as well as the specific
logic implemented in the cipher.
</para>
<para>
The ASCII art picture also indicates the call structure, i.e. who
calls which component. The arrows point to the invoked block
where the caller uses the API applicable to the cipher type
specified for the block.
</para>
<programlisting>
<![CDATA[
kernel crypto API | IPSEC Layer
|
+-----------+ |
| | (1)
| givcipher | <----------------------------------- esp_output
| (seqiv) | ---+
+-----------+ |
| (2)
+-----------+ |
| | <--+ (2)
| aead | <----------------------------------- esp_input
| (gcm) | ------------+
+-----------+ |
| (3) | (5)
v v
+-----------+ +-----------+
| | | |
| ablkcipher| | ahash |
| (ctr) | ---+ | (ghash) |
+-----------+ | +-----------+
|
+-----------+ | (4)
| | <--+
| cipher |
| (aes) |
+-----------+
]]>
</programlisting>
<para>
The following call sequence is applicable when the IPSEC layer
triggers an encryption operation with the esp_output function. During
configuration, the administrator set up the use of rfc4106(gcm(aes)) as
the cipher for ESP. The following call sequence is now depicted in the
ASCII art above:
</para>
<orderedlist>
<listitem>
<para>
esp_output() invokes crypto_aead_givencrypt() to trigger an encryption
operation of the GIVCIPHER implementation.
</para>
<para>
In case of GCM, the SEQIV implementation is registered as GIVCIPHER
in crypto_rfc4106_alloc().
</para>
<para>
The SEQIV performs its operation to generate an IV where the core
function is seqiv_geniv().
</para>
</listitem>
<listitem>
<para>
Now, SEQIV uses the AEAD API function calls to invoke the associated
AEAD cipher. In our case, during the instantiation of SEQIV, the
cipher handle for GCM is provided to SEQIV. This means that SEQIV
invokes AEAD cipher operations with the GCM cipher handle.
</para>
<para>
During instantiation of the GCM handle, the CTR(AES) and GHASH
ciphers are instantiated. The cipher handles for CTR(AES) and GHASH
are retained for later use.
</para>
<para>
The GCM implementation is responsible to invoke the CTR mode AES and
the GHASH cipher in the right manner to implement the GCM
specification.
</para>
</listitem>
<listitem>
<para>
The GCM AEAD cipher type implementation now invokes the ABLKCIPHER API
with the instantiated CTR(AES) cipher handle.
</para>
<para>
During instantiation of the CTR(AES) cipher, the CIPHER type
implementation of AES is instantiated. The cipher handle for AES is
retained.
</para>
<para>
That means that the ABLKCIPHER implementation of CTR(AES) only
implements the CTR block chaining mode. After performing the block
chaining operation, the CIPHER implementation of AES is invoked.
</para>
</listitem>
<listitem>
<para>
The ABLKCIPHER of CTR(AES) now invokes the CIPHER API with the AES
cipher handle to encrypt one block.
</para>
</listitem>
<listitem>
<para>
The GCM AEAD implementation also invokes the GHASH cipher
implementation via the AHASH API.
</para>
</listitem>
</orderedlist>
<para>
When the IPSEC layer triggers the esp_input() function, the same call
sequence is followed with the only difference that the operation starts
with step (2).
</para>
</sect2>
<sect2><title>Generic Block Cipher Structure</title>
<para>
Generic block ciphers follow the same concept as depicted with the ASCII
art picture above.
</para>
<para>
For example, CBC(AES) is implemented with cbc.c, and aes-generic.c. The
ASCII art picture above applies as well with the difference that only
step (4) is used and the ABLKCIPHER block chaining mode is CBC.
</para>
</sect2>
<sect2><title>Generic Keyed Message Digest Structure</title>
<para>
Keyed message digest implementations again follow the same concept as
depicted in the ASCII art picture above.
</para>
<para>
For example, HMAC(SHA256) is implemented with hmac.c and
sha256_generic.c. The following ASCII art illustrates the
implementation:
</para>
<programlisting>
<![CDATA[
kernel crypto API | Caller
|
+-----------+ (1) |
| | <------------------ some_function
| ahash |
| (hmac) | ---+
+-----------+ |
| (2)
+-----------+ |
| | <--+
| shash |
| (sha256) |
+-----------+
]]>
</programlisting>
<para>
The following call sequence is applicable when a caller triggers
an HMAC operation:
</para>
<orderedlist>
<listitem>
<para>
The AHASH API functions are invoked by the caller. The HMAC
implementation performs its operation as needed.
</para>
<para>
During initialization of the HMAC cipher, the SHASH cipher type of
SHA256 is instantiated. The cipher handle for the SHA256 instance is
retained.
</para>
<para>
At one time, the HMAC implementation requires a SHA256 operation
where the SHA256 cipher handle is used.
</para>
</listitem>
<listitem>
<para>
The HMAC instance now invokes the SHASH API with the SHA256
cipher handle to calculate the message digest.
</para>
</listitem>
</orderedlist>
</sect2>
</sect1>
</chapter>
<chapter id="Development"><title>Developing Cipher Algorithms</title>
@ -808,6 +1072,602 @@
</sect1>
</chapter>
<chapter id="User"><title>User Space Interface</title>
<sect1><title>Introduction</title>
<para>
The concepts of the kernel crypto API visible to kernel space is fully
applicable to the user space interface as well. Therefore, the kernel
crypto API high level discussion for the in-kernel use cases applies
here as well.
</para>
<para>
The major difference, however, is that user space can only act as a
consumer and never as a provider of a transformation or cipher algorithm.
</para>
<para>
The following covers the user space interface exported by the kernel
crypto API. A working example of this description is libkcapi that
can be obtained from [1]. That library can be used by user space
applications that require cryptographic services from the kernel.
</para>
<para>
Some details of the in-kernel kernel crypto API aspects do not
apply to user space, however. This includes the difference between
synchronous and asynchronous invocations. The user space API call
is fully synchronous.
</para>
<para>
[1] http://www.chronox.de/libkcapi.html
</para>
</sect1>
<sect1><title>User Space API General Remarks</title>
<para>
The kernel crypto API is accessible from user space. Currently,
the following ciphers are accessible:
</para>
<itemizedlist>
<listitem>
<para>Message digest including keyed message digest (HMAC, CMAC)</para>
</listitem>
<listitem>
<para>Symmetric ciphers</para>
</listitem>
<listitem>
<para>AEAD ciphers</para>
</listitem>
<listitem>
<para>Random Number Generators</para>
</listitem>
</itemizedlist>
<para>
The interface is provided via socket type using the type AF_ALG.
In addition, the setsockopt option type is SOL_ALG. In case the
user space header files do not export these flags yet, use the
following macros:
</para>
<programlisting>
#ifndef AF_ALG
#define AF_ALG 38
#endif
#ifndef SOL_ALG
#define SOL_ALG 279
#endif
</programlisting>
<para>
A cipher is accessed with the same name as done for the in-kernel
API calls. This includes the generic vs. unique naming schema for
ciphers as well as the enforcement of priorities for generic names.
</para>
<para>
To interact with the kernel crypto API, a socket must be
created by the user space application. User space invokes the cipher
operation with the send()/write() system call family. The result of the
cipher operation is obtained with the read()/recv() system call family.
</para>
<para>
The following API calls assume that the socket descriptor
is already opened by the user space application and discusses only
the kernel crypto API specific invocations.
</para>
<para>
To initialize the socket interface, the following sequence has to
be performed by the consumer:
</para>
<orderedlist>
<listitem>
<para>
Create a socket of type AF_ALG with the struct sockaddr_alg
parameter specified below for the different cipher types.
</para>
</listitem>
<listitem>
<para>
Invoke bind with the socket descriptor
</para>
</listitem>
<listitem>
<para>
Invoke accept with the socket descriptor. The accept system call
returns a new file descriptor that is to be used to interact with
the particular cipher instance. When invoking send/write or recv/read
system calls to send data to the kernel or obtain data from the
kernel, the file descriptor returned by accept must be used.
</para>
</listitem>
</orderedlist>
</sect1>
<sect1><title>In-place Cipher operation</title>
<para>
Just like the in-kernel operation of the kernel crypto API, the user
space interface allows the cipher operation in-place. That means that
the input buffer used for the send/write system call and the output
buffer used by the read/recv system call may be one and the same.
This is of particular interest for symmetric cipher operations where a
copying of the output data to its final destination can be avoided.
</para>
<para>
If a consumer on the other hand wants to maintain the plaintext and
the ciphertext in different memory locations, all a consumer needs
to do is to provide different memory pointers for the encryption and
decryption operation.
</para>
</sect1>
<sect1><title>Message Digest API</title>
<para>
The message digest type to be used for the cipher operation is
selected when invoking the bind syscall. bind requires the caller
to provide a filled struct sockaddr data structure. This data
structure must be filled as follows:
</para>
<programlisting>
struct sockaddr_alg sa = {
.salg_family = AF_ALG,
.salg_type = "hash", /* this selects the hash logic in the kernel */
.salg_name = "sha1" /* this is the cipher name */
};
</programlisting>
<para>
The salg_type value "hash" applies to message digests and keyed
message digests. Though, a keyed message digest is referenced by
the appropriate salg_name. Please see below for the setsockopt
interface that explains how the key can be set for a keyed message
digest.
</para>
<para>
Using the send() system call, the application provides the data that
should be processed with the message digest. The send system call
allows the following flags to be specified:
</para>
<itemizedlist>
<listitem>
<para>
MSG_MORE: If this flag is set, the send system call acts like a
message digest update function where the final hash is not
yet calculated. If the flag is not set, the send system call
calculates the final message digest immediately.
</para>
</listitem>
</itemizedlist>
<para>
With the recv() system call, the application can read the message
digest from the kernel crypto API. If the buffer is too small for the
message digest, the flag MSG_TRUNC is set by the kernel.
</para>
<para>
In order to set a message digest key, the calling application must use
the setsockopt() option of ALG_SET_KEY. If the key is not set the HMAC
operation is performed without the initial HMAC state change caused by
the key.
</para>
</sect1>
<sect1><title>Symmetric Cipher API</title>
<para>
The operation is very similar to the message digest discussion.
During initialization, the struct sockaddr data structure must be
filled as follows:
</para>
<programlisting>
struct sockaddr_alg sa = {
.salg_family = AF_ALG,
.salg_type = "skcipher", /* this selects the symmetric cipher */
.salg_name = "cbc(aes)" /* this is the cipher name */
};
</programlisting>
<para>
Before data can be sent to the kernel using the write/send system
call family, the consumer must set the key. The key setting is
described with the setsockopt invocation below.
</para>
<para>
Using the sendmsg() system call, the application provides the data that should be processed for encryption or decryption. In addition, the IV is
specified with the data structure provided by the sendmsg() system call.
</para>
<para>
The sendmsg system call parameter of struct msghdr is embedded into the
struct cmsghdr data structure. See recv(2) and cmsg(3) for more
information on how the cmsghdr data structure is used together with the
send/recv system call family. That cmsghdr data structure holds the
following information specified with a separate header instances:
</para>
<itemizedlist>
<listitem>
<para>
specification of the cipher operation type with one of these flags:
</para>
<itemizedlist>
<listitem>
<para>ALG_OP_ENCRYPT - encryption of data</para>
</listitem>
<listitem>
<para>ALG_OP_DECRYPT - decryption of data</para>
</listitem>
</itemizedlist>
</listitem>
<listitem>
<para>
specification of the IV information marked with the flag ALG_SET_IV
</para>
</listitem>
</itemizedlist>
<para>
The send system call family allows the following flag to be specified:
</para>
<itemizedlist>
<listitem>
<para>
MSG_MORE: If this flag is set, the send system call acts like a
cipher update function where more input data is expected
with a subsequent invocation of the send system call.
</para>
</listitem>
</itemizedlist>
<para>
Note: The kernel reports -EINVAL for any unexpected data. The caller
must make sure that all data matches the constraints given in
/proc/crypto for the selected cipher.
</para>
<para>
With the recv() system call, the application can read the result of
the cipher operation from the kernel crypto API. The output buffer
must be at least as large as to hold all blocks of the encrypted or
decrypted data. If the output data size is smaller, only as many
blocks are returned that fit into that output buffer size.
</para>
</sect1>
<sect1><title>AEAD Cipher API</title>
<para>
The operation is very similar to the symmetric cipher discussion.
During initialization, the struct sockaddr data structure must be
filled as follows:
</para>
<programlisting>
struct sockaddr_alg sa = {
.salg_family = AF_ALG,
.salg_type = "aead", /* this selects the symmetric cipher */
.salg_name = "gcm(aes)" /* this is the cipher name */
};
</programlisting>
<para>
Before data can be sent to the kernel using the write/send system
call family, the consumer must set the key. The key setting is
described with the setsockopt invocation below.
</para>
<para>
In addition, before data can be sent to the kernel using the
write/send system call family, the consumer must set the authentication
tag size. To set the authentication tag size, the caller must use the
setsockopt invocation described below.
</para>
<para>
Using the sendmsg() system call, the application provides the data that should be processed for encryption or decryption. In addition, the IV is
specified with the data structure provided by the sendmsg() system call.
</para>
<para>
The sendmsg system call parameter of struct msghdr is embedded into the
struct cmsghdr data structure. See recv(2) and cmsg(3) for more
information on how the cmsghdr data structure is used together with the
send/recv system call family. That cmsghdr data structure holds the
following information specified with a separate header instances:
</para>
<itemizedlist>
<listitem>
<para>
specification of the cipher operation type with one of these flags:
</para>
<itemizedlist>
<listitem>
<para>ALG_OP_ENCRYPT - encryption of data</para>
</listitem>
<listitem>
<para>ALG_OP_DECRYPT - decryption of data</para>
</listitem>
</itemizedlist>
</listitem>
<listitem>
<para>
specification of the IV information marked with the flag ALG_SET_IV
</para>
</listitem>
<listitem>
<para>
specification of the associated authentication data (AAD) with the
flag ALG_SET_AEAD_ASSOCLEN. The AAD is sent to the kernel together
with the plaintext / ciphertext. See below for the memory structure.
</para>
</listitem>
</itemizedlist>
<para>
The send system call family allows the following flag to be specified:
</para>
<itemizedlist>
<listitem>
<para>
MSG_MORE: If this flag is set, the send system call acts like a
cipher update function where more input data is expected
with a subsequent invocation of the send system call.
</para>
</listitem>
</itemizedlist>
<para>
Note: The kernel reports -EINVAL for any unexpected data. The caller
must make sure that all data matches the constraints given in
/proc/crypto for the selected cipher.
</para>
<para>
With the recv() system call, the application can read the result of
the cipher operation from the kernel crypto API. The output buffer
must be at least as large as defined with the memory structure below.
If the output data size is smaller, the cipher operation is not performed.
</para>
<para>
The authenticated decryption operation may indicate an integrity error.
Such breach in integrity is marked with the -EBADMSG error code.
</para>
<sect2><title>AEAD Memory Structure</title>
<para>
The AEAD cipher operates with the following information that
is communicated between user and kernel space as one data stream:
</para>
<itemizedlist>
<listitem>
<para>plaintext or ciphertext</para>
</listitem>
<listitem>
<para>associated authentication data (AAD)</para>
</listitem>
<listitem>
<para>authentication tag</para>
</listitem>
</itemizedlist>
<para>
The sizes of the AAD and the authentication tag are provided with
the sendmsg and setsockopt calls (see there). As the kernel knows
the size of the entire data stream, the kernel is now able to
calculate the right offsets of the data components in the data
stream.
</para>
<para>
The user space caller must arrange the aforementioned information
in the following order:
</para>
<itemizedlist>
<listitem>
<para>
AEAD encryption input: AAD || plaintext
</para>
</listitem>
<listitem>
<para>
AEAD decryption input: AAD || ciphertext || authentication tag
</para>
</listitem>
</itemizedlist>
<para>
The output buffer the user space caller provides must be at least as
large to hold the following data:
</para>
<itemizedlist>
<listitem>
<para>
AEAD encryption output: ciphertext || authentication tag
</para>
</listitem>
<listitem>
<para>
AEAD decryption output: plaintext
</para>
</listitem>
</itemizedlist>
</sect2>
</sect1>
<sect1><title>Random Number Generator API</title>
<para>
Again, the operation is very similar to the other APIs.
During initialization, the struct sockaddr data structure must be
filled as follows:
</para>
<programlisting>
struct sockaddr_alg sa = {
.salg_family = AF_ALG,
.salg_type = "rng", /* this selects the symmetric cipher */
.salg_name = "drbg_nopr_sha256" /* this is the cipher name */
};
</programlisting>
<para>
Depending on the RNG type, the RNG must be seeded. The seed is provided
using the setsockopt interface to set the key. For example, the
ansi_cprng requires a seed. The DRBGs do not require a seed, but
may be seeded.
</para>
<para>
Using the read()/recvmsg() system calls, random numbers can be obtained.
The kernel generates at most 128 bytes in one call. If user space
requires more data, multiple calls to read()/recvmsg() must be made.
</para>
<para>
WARNING: The user space caller may invoke the initially mentioned
accept system call multiple times. In this case, the returned file
descriptors have the same state.
</para>
</sect1>
<sect1><title>Zero-Copy Interface</title>
<para>
In addition to the send/write/read/recv system call familty, the AF_ALG
interface can be accessed with the zero-copy interface of splice/vmsplice.
As the name indicates, the kernel tries to avoid a copy operation into
kernel space.
</para>
<para>
The zero-copy operation requires data to be aligned at the page boundary.
Non-aligned data can be used as well, but may require more operations of
the kernel which would defeat the speed gains obtained from the zero-copy
interface.
</para>
<para>
The system-interent limit for the size of one zero-copy operation is
16 pages. If more data is to be sent to AF_ALG, user space must slice
the input into segments with a maximum size of 16 pages.
</para>
<para>
Zero-copy can be used with the following code example (a complete working
example is provided with libkcapi):
</para>
<programlisting>
int pipes[2];
pipe(pipes);
/* input data in iov */
vmsplice(pipes[1], iov, iovlen, SPLICE_F_GIFT);
/* opfd is the file descriptor returned from accept() system call */
splice(pipes[0], NULL, opfd, NULL, ret, 0);
read(opfd, out, outlen);
</programlisting>
</sect1>
<sect1><title>Setsockopt Interface</title>
<para>
In addition to the read/recv and send/write system call handling
to send and retrieve data subject to the cipher operation, a consumer
also needs to set the additional information for the cipher operation.
This additional information is set using the setsockopt system call
that must be invoked with the file descriptor of the open cipher
(i.e. the file descriptor returned by the accept system call).
</para>
<para>
Each setsockopt invocation must use the level SOL_ALG.
</para>
<para>
The setsockopt interface allows setting the following data using
the mentioned optname:
</para>
<itemizedlist>
<listitem>
<para>
ALG_SET_KEY -- Setting the key. Key setting is applicable to:
</para>
<itemizedlist>
<listitem>
<para>the skcipher cipher type (symmetric ciphers)</para>
</listitem>
<listitem>
<para>the hash cipher type (keyed message digests)</para>
</listitem>
<listitem>
<para>the AEAD cipher type</para>
</listitem>
<listitem>
<para>the RNG cipher type to provide the seed</para>
</listitem>
</itemizedlist>
</listitem>
<listitem>
<para>
ALG_SET_AEAD_AUTHSIZE -- Setting the authentication tag size
for AEAD ciphers. For a encryption operation, the authentication
tag of the given size will be generated. For a decryption operation,
the provided ciphertext is assumed to contain an authentication tag
of the given size (see section about AEAD memory layout below).
</para>
</listitem>
</itemizedlist>
</sect1>
<sect1><title>User space API example</title>
<para>
Please see [1] for libkcapi which provides an easy-to-use wrapper
around the aforementioned Netlink kernel interface. [1] also contains
a test application that invokes all libkcapi API calls.
</para>
<para>
[1] http://www.chronox.de/libkcapi.html
</para>
</sect1>
</chapter>
<chapter id="API"><title>Programming Interface</title>
<sect1><title>Block Cipher Context Data Structures</title>
!Pinclude/linux/crypto.h Block Cipher Context Data Structures

31
Documentation/DocBook/drm.tmpl
View File

@ -1293,7 +1293,7 @@ int max_width, max_height;</synopsis>
</para>
<para>
If a page flip can be successfully scheduled the driver must set the
<code>drm_crtc-&lt;fb</code> field to the new framebuffer pointed to
<code>drm_crtc-&gt;fb</code> field to the new framebuffer pointed to
by <code>fb</code>. This is important so that the reference counting
on framebuffers stays balanced.
</para>
@ -3979,6 +3979,11 @@ int num_ioctls;</synopsis>
!Fdrivers/gpu/drm/i915/i915_irq.c intel_runtime_pm_disable_interrupts
!Fdrivers/gpu/drm/i915/i915_irq.c intel_runtime_pm_enable_interrupts
</sect2>
<sect2>
<title>Intel GVT-g Guest Support(vGPU)</title>
!Pdrivers/gpu/drm/i915/i915_vgpu.c Intel GVT-g guest support
!Idrivers/gpu/drm/i915/i915_vgpu.c
</sect2>
</sect1>
<sect1>
<title>Display Hardware Handling</title>
@ -4046,6 +4051,17 @@ int num_ioctls;</synopsis>
<title>Frame Buffer Compression (FBC)</title>
!Pdrivers/gpu/drm/i915/intel_fbc.c Frame Buffer Compression (FBC)
!Idrivers/gpu/drm/i915/intel_fbc.c
</sect2>
<sect2>
<title>Display Refresh Rate Switching (DRRS)</title>
!Pdrivers/gpu/drm/i915/intel_dp.c Display Refresh Rate Switching (DRRS)
!Fdrivers/gpu/drm/i915/intel_dp.c intel_dp_set_drrs_state
!Fdrivers/gpu/drm/i915/intel_dp.c intel_edp_drrs_enable
!Fdrivers/gpu/drm/i915/intel_dp.c intel_edp_drrs_disable
!Fdrivers/gpu/drm/i915/intel_dp.c intel_edp_drrs_invalidate
!Fdrivers/gpu/drm/i915/intel_dp.c intel_edp_drrs_flush
!Fdrivers/gpu/drm/i915/intel_dp.c intel_dp_drrs_init
</sect2>
<sect2>
<title>DPIO</title>
@ -4168,7 +4184,7 @@ int num_ioctls;</synopsis>
<sect2>
<title>Buffer Object Eviction</title>
<para>
This section documents the interface function for evicting buffer
This section documents the interface functions for evicting buffer
objects to make space available in the virtual gpu address spaces.
Note that this is mostly orthogonal to shrinking buffer objects
caches, which has the goal to make main memory (shared with the gpu
@ -4176,6 +4192,17 @@ int num_ioctls;</synopsis>
</para>
!Idrivers/gpu/drm/i915/i915_gem_evict.c
</sect2>
<sect2>
<title>Buffer Object Memory Shrinking</title>
<para>
This section documents the interface function for shrinking memory
usage of buffer object caches. Shrinking is used to make main memory
available. Note that this is mostly orthogonal to evicting buffer
objects, which has the goal to make space in gpu virtual address
spaces.
</para>
!Idrivers/gpu/drm/i915/i915_gem_shrinker.c
</sect2>
</sect1>
<sect1>

11
Documentation/DocBook/media/v4l/biblio.xml
View File

@ -1,14 +1,13 @@
<bibliography>
<title>References</title>
<biblioentry id="eia608">
<abbrev>EIA&nbsp;608-B</abbrev>
<biblioentry id="cea608">
<abbrev>CEA&nbsp;608-E</abbrev>
<authorgroup>
<corpauthor>Electronic Industries Alliance (<ulink
url="http://www.eia.org">http://www.eia.org</ulink>)</corpauthor>
<corpauthor>Consumer Electronics Association (<ulink
url="http://www.ce.org">http://www.ce.org</ulink>)</corpauthor>
</authorgroup>
<title>EIA 608-B "Recommended Practice for Line 21 Data
Service"</title>
<title>CEA-608-E R-2014 "Line 21 Data Services"</title>
</biblioentry>
<biblioentry id="en300294">

2
Documentation/DocBook/media/v4l/compat.xml
View File

@ -2491,7 +2491,7 @@ that used it. It was originally scheduled for removal in 2.6.35.
</listitem>
<listitem>
<para>Added <constant>V4L2_EVENT_CTRL_CH_RANGE</constant> control event
changes flag. See <xref linkend="changes-flags"/>.</para>
changes flag. See <xref linkend="ctrl-changes-flags"/>.</para>
</listitem>
</orderedlist>
</section>

2
Documentation/DocBook/media/v4l/dev-sliced-vbi.xml
View File

@ -254,7 +254,7 @@ ETS&nbsp;300&nbsp;231, lsb first transmitted.</entry>
<row>
<entry><constant>V4L2_SLICED_CAPTION_525</constant></entry>
<entry>0x1000</entry>
<entry><xref linkend="eia608" /></entry>
<entry><xref linkend="cea608" /></entry>
<entry>NTSC line 21, 284 (second field 21)</entry>
<entry>Two bytes in transmission order, including parity
bit, lsb first transmitted.</entry>

92
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View File

@ -143,86 +143,28 @@
<row>
<entry></entry>
<entry>struct</entry>
<entry><structfield>v4l</structfield></entry>
<entry><structfield>dev</structfield></entry>
<entry></entry>
<entry>Valid for V4L sub-devices and nodes only.</entry>
<entry>Valid for (sub-)devices that create a single device node.</entry>
</row>
<row>
<entry></entry>
<entry></entry>
<entry>__u32</entry>
<entry><structfield>major</structfield></entry>
<entry>V4L device node major number. For V4L sub-devices with no
device node, set by the driver to 0.</entry>
<entry>Device node major number.</entry>
</row>
<row>
<entry></entry>
<entry></entry>
<entry>__u32</entry>
<entry><structfield>minor</structfield></entry>
<entry>V4L device node minor number. For V4L sub-devices with no
device node, set by the driver to 0.</entry>
</row>
<row>
<entry></entry>
<entry>struct</entry>
<entry><structfield>fb</structfield></entry>
<entry></entry>
<entry>Valid for frame buffer nodes only.</entry>
</row>
<row>
<entry></entry>
<entry></entry>
<entry>__u32</entry>
<entry><structfield>major</structfield></entry>
<entry>Frame buffer device node major number.</entry>
</row>
<row>
<entry></entry>
<entry></entry>
<entry>__u32</entry>
<entry><structfield>minor</structfield></entry>
<entry>Frame buffer device node minor number.</entry>
</row>
<row>
<entry></entry>
<entry>struct</entry>
<entry><structfield>alsa</structfield></entry>
<entry></entry>
<entry>Valid for ALSA devices only.</entry>
</row>
<row>
<entry></entry>
<entry></entry>
<entry>__u32</entry>
<entry><structfield>card</structfield></entry>
<entry>ALSA card number</entry>
</row>
<row>
<entry></entry>
<entry></entry>
<entry>__u32</entry>
<entry><structfield>device</structfield></entry>
<entry>ALSA device number</entry>
</row>
<row>
<entry></entry>
<entry></entry>
<entry>__u32</entry>
<entry><structfield>subdevice</structfield></entry>
<entry>ALSA sub-device number</entry>
</row>
<row>
<entry></entry>
<entry>int</entry>
<entry><structfield>dvb</structfield></entry>
<entry></entry>
<entry>DVB card number</entry>
<entry>Device node minor number.</entry>
</row>
<row>
<entry></entry>
<entry>__u8</entry>
<entry><structfield>raw</structfield>[180]</entry>
<entry><structfield>raw</structfield>[184]</entry>
<entry></entry>
<entry></entry>
</row>
@ -253,8 +195,24 @@
<entry>ALSA card</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_DEVNODE_DVB</constant></entry>
<entry>DVB card</entry>
<entry><constant>MEDIA_ENT_T_DEVNODE_DVB_FE</constant></entry>
<entry>DVB frontend devnode</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_DEVNODE_DVB_DEMUX</constant></entry>
<entry>DVB demux devnode</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_DEVNODE_DVB_DVR</constant></entry>
<entry>DVB DVR devnode</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_DEVNODE_DVB_CA</constant></entry>
<entry>DVB CAM devnode</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_DEVNODE_DVB_NET</constant></entry>
<entry>DVB network devnode</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_V4L2_SUBDEV</constant></entry>
@ -282,6 +240,10 @@
it in some digital video standard, with appropriate embedded timing
signals.</entry>
</row>
<row>
<entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_TUNER</constant></entry>
<entry>TV and/or radio tuner</entry>
</row>
</tbody>
</tgroup>
</table>

79
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View File

@ -303,45 +303,6 @@ for a pixel lie next to each other in memory.</para>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-BGR666">
<entry><constant>V4L2_PIX_FMT_BGR666</constant></entry>
<entry>'BGRH'</entry>
<entry></entry>
<entry>b<subscript>5</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
<entry>g<subscript>5</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry></entry>
<entry>g<subscript>3</subscript></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry>r<subscript>5</subscript></entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry></entry>
<entry></entry>
<entry></entry>
<entry></entry>
<entry></entry>
<entry></entry>
<entry></entry>
<entry></entry>
<entry></entry>
<entry></entry>
<entry></entry>
<entry></entry>
<entry></entry>
<entry></entry>
</row>
<row id="V4L2-PIX-FMT-BGR24">
<entry><constant>V4L2_PIX_FMT_BGR24</constant></entry>
<entry>'BGR3'</entry>
@ -404,6 +365,46 @@ for a pixel lie next to each other in memory.</para>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-BGR666">
<entry><constant>V4L2_PIX_FMT_BGR666</constant></entry>
<entry>'BGRH'</entry>
<entry></entry>
<entry>b<subscript>5</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
<entry>g<subscript>5</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry></entry>
<entry>g<subscript>3</subscript></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry>r<subscript>5</subscript></entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry></entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
</row>
<row id="V4L2-PIX-FMT-ABGR32">
<entry><constant>V4L2_PIX_FMT_ABGR32</constant></entry>
<entry>'AR24'</entry>

16
Documentation/DocBook/media/v4l/pixfmt-sgrbg8.xml
View File

@ -38,10 +38,10 @@ columns and rows.</para>
</row>
<row>
<entry>start&nbsp;+&nbsp;4:</entry>
<entry>R<subscript>10</subscript></entry>
<entry>B<subscript>11</subscript></entry>
<entry>R<subscript>12</subscript></entry>
<entry>B<subscript>13</subscript></entry>
<entry>B<subscript>10</subscript></entry>
<entry>G<subscript>11</subscript></entry>
<entry>B<subscript>12</subscript></entry>
<entry>G<subscript>13</subscript></entry>
</row>
<row>
<entry>start&nbsp;+&nbsp;8:</entry>
@ -52,10 +52,10 @@ columns and rows.</para>
</row>
<row>
<entry>start&nbsp;+&nbsp;12:</entry>
<entry>R<subscript>30</subscript></entry>
<entry>B<subscript>31</subscript></entry>
<entry>R<subscript>32</subscript></entry>
<entry>B<subscript>33</subscript></entry>
<entry>B<subscript>30</subscript></entry>
<entry>G<subscript>31</subscript></entry>
<entry>B<subscript>32</subscript></entry>
<entry>G<subscript>33</subscript></entry>
</row>
</tbody>
</tgroup>

2
Documentation/DocBook/media/v4l/pixfmt-srggb10p.xml
View File

@ -38,7 +38,7 @@
<title>Byte Order.</title>
<para>Each cell is one byte.
<informaltable frame="topbot" colsep="1" rowsep="1">
<tgroup cols="5" align="center" border="1">
<tgroup cols="5" align="center">
<colspec align="left" colwidth="2*" />
<tbody valign="top">
<row>

4
Documentation/DocBook/media/v4l/pixfmt-yuv420m.xml
View File

@ -29,12 +29,12 @@ and Cr planes have half as many pad bytes after their rows. In other
words, two Cx rows (including padding) is exactly as long as one Y row
(including padding).</para>
<para><constant>V4L2_PIX_FMT_NV12M</constant> is intended to be
<para><constant>V4L2_PIX_FMT_YUV420M</constant> is intended to be
used only in drivers and applications that support the multi-planar API,
described in <xref linkend="planar-apis"/>. </para>
<example>
<title><constant>V4L2_PIX_FMT_YVU420M</constant> 4 &times; 4
<title><constant>V4L2_PIX_FMT_YUV420M</constant> 4 &times; 4
pixel image</title>
<formalpara>

110
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View File

@ -80,9 +80,9 @@ padding bytes after the last line of an image cross a system page
boundary. Input devices may write padding bytes, the value is
undefined. Output devices ignore the contents of padding
bytes.</para><para>When the image format is planar the
<structfield>bytesperline</structfield> value applies to the largest
<structfield>bytesperline</structfield> value applies to the first
plane and is divided by the same factor as the
<structfield>width</structfield> field for any smaller planes. For
<structfield>width</structfield> field for the other planes. For
example the Cb and Cr planes of a YUV 4:2:0 image have half as many
padding bytes following each line as the Y plane. To avoid ambiguities
drivers must return a <structfield>bytesperline</structfield> value
@ -182,14 +182,14 @@ see <xref linkend="colorspaces" />.</entry>
</entry>
</row>
<row>
<entry>__u16</entry>
<entry>__u32</entry>
<entry><structfield>bytesperline</structfield></entry>
<entry>Distance in bytes between the leftmost pixels in two adjacent
lines. See &v4l2-pix-format;.</entry>
</row>
<row>
<entry>__u16</entry>
<entry><structfield>reserved[7]</structfield></entry>
<entry><structfield>reserved[6]</structfield></entry>
<entry>Reserved for future extensions. Should be zeroed by the
application.</entry>
</row>
@ -483,8 +483,8 @@ is the Y'CbCr encoding identifier (&v4l2-ycbcr-encoding;) to specify non-standar
Y'CbCr encodings and the third is the quantization identifier (&v4l2-quantization;)
to specify non-standard quantization methods. Most of the time only the colorspace
field of &v4l2-pix-format; or &v4l2-pix-format-mplane; needs to be filled in. Note
that the default R'G'B' quantization is always full range for all colorspaces,
so this won't be mentioned explicitly for each colorspace description.</para>
that the default R'G'B' quantization is full range for all colorspaces except for
BT.2020 which uses limited range R'G'B' quantization.</para>
<table pgwide="1" frame="none" id="v4l2-colorspace">
<title>V4L2 Colorspaces</title>
@ -598,7 +598,8 @@ so this won't be mentioned explicitly for each colorspace description.</para>
<row>
<entry><constant>V4L2_QUANTIZATION_DEFAULT</constant></entry>
<entry>Use the default quantization encoding as defined by the colorspace.
This is always full range for R'G'B' and usually limited range for Y'CbCr.</entry>
This is always full range for R'G'B' (except for the BT.2020 colorspace) and usually
limited range for Y'CbCr.</entry>
</row>
<row>
<entry><constant>V4L2_QUANTIZATION_FULL_RANGE</constant></entry>
@ -620,8 +621,8 @@ is mapped to [16&hellip;235]. Cb and Cr are mapped from [-0.5&hellip;0.5] to [16
<section>
<title>Detailed Colorspace Descriptions</title>
<section>
<title id="col-smpte-170m">Colorspace SMPTE 170M (<constant>V4L2_COLORSPACE_SMPTE170M</constant>)</title>
<section id="col-smpte-170m">
<title>Colorspace SMPTE 170M (<constant>V4L2_COLORSPACE_SMPTE170M</constant>)</title>
<para>The <xref linkend="smpte170m" /> standard defines the colorspace used by NTSC and PAL and by SDTV
in general. The default Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_601</constant>.
The default Y'CbCr quantization is limited range. The chromaticities of the primary colors and
@ -666,8 +667,7 @@ as the SMPTE C set, so this colorspace is sometimes called SMPTE C as well.</par
<variablelist>
<varlistentry>
<term>The transfer function defined for SMPTE 170M is the same as the
one defined in Rec. 709. Normally L is in the range [0&hellip;1], but for the extended
gamut xvYCC encoding values outside that range are allowed.</term>
one defined in Rec. 709.</term>
<listitem>
<para>L' = -1.099(-L)<superscript>0.45</superscript>&nbsp;+&nbsp;0.099&nbsp;for&nbsp;L&nbsp;&le;&nbsp;-0.018</para>
<para>L' = 4.5L&nbsp;for&nbsp;-0.018&nbsp;&lt;&nbsp;L&nbsp;&lt;&nbsp;0.018</para>
@ -702,29 +702,10 @@ defined in the <xref linkend="itu601" /> standard and this colorspace is sometim
though BT.601 does not mention any color primaries.</para>
<para>The default quantization is limited range, but full range is possible although
rarely seen.</para>
<para>The <constant>V4L2_YCBCR_ENC_601</constant> encoding as described above is the
default for this colorspace, but it can be overridden with <constant>V4L2_YCBCR_ENC_709</constant>,
in which case the Rec. 709 Y'CbCr encoding is used.</para>
<variablelist>
<varlistentry>
<term>The xvYCC 601 encoding (<constant>V4L2_YCBCR_ENC_XV601</constant>, <xref linkend="xvycc" />) is similar
to the BT.601 encoding, but it allows for R', G' and B' values that are outside the range
[0&hellip;1]. The resulting Y', Cb and Cr values are scaled and offset:</term>
<listitem>
<para>Y'&nbsp;=&nbsp;(219&nbsp;/&nbsp;255)&nbsp;*&nbsp;(0.299R'&nbsp;+&nbsp;0.587G'&nbsp;+&nbsp;0.114B')&nbsp;+&nbsp;(16&nbsp;/&nbsp;255)</para>
<para>Cb&nbsp;=&nbsp;(224&nbsp;/&nbsp;255)&nbsp;*&nbsp;(-0.169R'&nbsp;-&nbsp;0.331G'&nbsp;+&nbsp;0.5B')</para>
<para>Cr&nbsp;=&nbsp;(224&nbsp;/&nbsp;255)&nbsp;*&nbsp;(0.5R'&nbsp;-&nbsp;0.419G'&nbsp;-&nbsp;0.081B')</para>
</listitem>
</varlistentry>
</variablelist>
<para>Y' is clamped to the range [0&hellip;1] and Cb and Cr are clamped
to the range [-0.5&hellip;0.5]. The non-standard xvYCC 709 encoding can also be used by selecting
<constant>V4L2_YCBCR_ENC_XV709</constant>. The xvYCC encodings always use full range
quantization.</para>
</section>
<section>
<title id="col-rec709">Colorspace Rec. 709 (<constant>V4L2_COLORSPACE_REC709</constant>)</title>
<section id="col-rec709">
<title>Colorspace Rec. 709 (<constant>V4L2_COLORSPACE_REC709</constant>)</title>
<para>The <xref linkend="itu709" /> standard defines the colorspace used by HDTV in general. The default
Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_709</constant>. The default Y'CbCr quantization is
limited range. The chromaticities of the primary colors and the white reference are:</para>
@ -803,26 +784,39 @@ rarely seen.</para>
<para>The <constant>V4L2_YCBCR_ENC_709</constant> encoding described above is the default
for this colorspace, but it can be overridden with <constant>V4L2_YCBCR_ENC_601</constant>, in which
case the BT.601 Y'CbCr encoding is used.</para>
<para>Two additional extended gamut Y'CbCr encodings are also possible with this colorspace:</para>
<variablelist>
<varlistentry>
<term>The xvYCC 709 encoding (<constant>V4L2_YCBCR_ENC_XV709</constant>, <xref linkend="xvycc" />)
is similar to the Rec. 709 encoding, but it allows for R', G' and B' values that are outside the range
[0&hellip;1]. The resulting Y', Cb and Cr values are scaled and offset:</term>
<listitem>
<para>Y'&nbsp;=&nbsp;(219&nbsp;/&nbsp;255)&nbsp;*&nbsp;(0.2126R'&nbsp;+&nbsp;0.7152G'&nbsp;+&nbsp;0.0722B')&nbsp;+&nbsp;(16&nbsp;/&nbsp;255)</para>
<para>Cb&nbsp;=&nbsp;(224&nbsp;/&nbsp;255)&nbsp;*&nbsp;(-0.1146R'&nbsp;-&nbsp;0.3854G'&nbsp;+&nbsp;0.5B')</para>
<para>Cr&nbsp;=&nbsp;(224&nbsp;/&nbsp;255)&nbsp;*&nbsp;(0.5R'&nbsp;-&nbsp;0.4542G'&nbsp;-&nbsp;0.0458B')</para>
<para>Y'&nbsp;=&nbsp;(219&nbsp;/&nbsp;256)&nbsp;*&nbsp;(0.2126R'&nbsp;+&nbsp;0.7152G'&nbsp;+&nbsp;0.0722B')&nbsp;+&nbsp;(16&nbsp;/&nbsp;256)</para>
<para>Cb&nbsp;=&nbsp;(224&nbsp;/&nbsp;256)&nbsp;*&nbsp;(-0.1146R'&nbsp;-&nbsp;0.3854G'&nbsp;+&nbsp;0.5B')</para>
<para>Cr&nbsp;=&nbsp;(224&nbsp;/&nbsp;256)&nbsp;*&nbsp;(0.5R'&nbsp;-&nbsp;0.4542G'&nbsp;-&nbsp;0.0458B')</para>
</listitem>
</varlistentry>
</variablelist>
<variablelist>
<varlistentry>
<term>The xvYCC 601 encoding (<constant>V4L2_YCBCR_ENC_XV601</constant>, <xref linkend="xvycc" />) is similar
to the BT.601 encoding, but it allows for R', G' and B' values that are outside the range
[0&hellip;1]. The resulting Y', Cb and Cr values are scaled and offset:</term>
<listitem>
<para>Y'&nbsp;=&nbsp;(219&nbsp;/&nbsp;256)&nbsp;*&nbsp;(0.299R'&nbsp;+&nbsp;0.587G'&nbsp;+&nbsp;0.114B')&nbsp;+&nbsp;(16&nbsp;/&nbsp;256)</para>
<para>Cb&nbsp;=&nbsp;(224&nbsp;/&nbsp;256)&nbsp;*&nbsp;(-0.169R'&nbsp;-&nbsp;0.331G'&nbsp;+&nbsp;0.5B')</para>
<para>Cr&nbsp;=&nbsp;(224&nbsp;/&nbsp;256)&nbsp;*&nbsp;(0.5R'&nbsp;-&nbsp;0.419G'&nbsp;-&nbsp;0.081B')</para>
</listitem>
</varlistentry>
</variablelist>
<para>Y' is clamped to the range [0&hellip;1] and Cb and Cr are clamped
to the range [-0.5&hellip;0.5]. The non-standard xvYCC 601 encoding can also be used by
selecting <constant>V4L2_YCBCR_ENC_XV601</constant>. The xvYCC encodings always use full
range quantization.</para>
to the range [-0.5&hellip;0.5]. The non-standard xvYCC 709 or xvYCC 601 encodings can be used by
selecting <constant>V4L2_YCBCR_ENC_XV709</constant> or <constant>V4L2_YCBCR_ENC_XV601</constant>.
The xvYCC encodings always use full range quantization.</para>
</section>
<section>
<title id="col-srgb">Colorspace sRGB (<constant>V4L2_COLORSPACE_SRGB</constant>)</title>
<section id="col-srgb">
<title>Colorspace sRGB (<constant>V4L2_COLORSPACE_SRGB</constant>)</title>
<para>The <xref linkend="srgb" /> standard defines the colorspace used by most webcams and computer graphics. The
default Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_SYCC</constant>. The default Y'CbCr quantization
is full range. The chromaticities of the primary colors and the white reference are:</para>
@ -898,8 +892,8 @@ encoding, it is not. The <constant>V4L2_YCBCR_ENC_XV601</constant> scales and of
values before quantization, but this encoding does not do that.</para>
</section>
<section>
<title id="col-adobergb">Colorspace Adobe RGB (<constant>V4L2_COLORSPACE_ADOBERGB</constant>)</title>
<section id="col-adobergb">
<title>Colorspace Adobe RGB (<constant>V4L2_COLORSPACE_ADOBERGB</constant>)</title>
<para>The <xref linkend="adobergb" /> standard defines the colorspace used by computer graphics
that use the AdobeRGB colorspace. This is also known as the <xref linkend="oprgb" /> standard.
The default Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_601</constant>. The default Y'CbCr
@ -970,12 +964,12 @@ clamped to the range [-0.5&hellip;0.5]. This transform is identical to one defin
SMPTE 170M/BT.601. The Y'CbCr quantization is limited range.</para>
</section>
<section>
<title id="col-bt2020">Colorspace BT.2020 (<constant>V4L2_COLORSPACE_BT2020</constant>)</title>
<section id="col-bt2020">
<title>Colorspace BT.2020 (<constant>V4L2_COLORSPACE_BT2020</constant>)</title>
<para>The <xref linkend="itu2020" /> standard defines the colorspace used by Ultra-high definition
television (UHDTV). The default Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_BT2020</constant>.
The default Y'CbCr quantization is limited range. The chromaticities of the primary colors and
the white reference are:</para>
The default R'G'B' quantization is limited range (!), and so is the default Y'CbCr quantization.
The chromaticities of the primary colors and the white reference are:</para>
<table frame="none">
<title>BT.2020 Chromaticities</title>
<tgroup cols="3" align="left">
@ -1032,7 +1026,7 @@ the white reference are:</para>
<term>The luminance (Y') and color difference (Cb and Cr) are obtained with the
following <constant>V4L2_YCBCR_ENC_BT2020</constant> encoding:</term>
<listitem>
<para>Y'&nbsp;=&nbsp;0.2627R'&nbsp;+&nbsp;0.6789G'&nbsp;+&nbsp;0.0593B'</para>
<para>Y'&nbsp;=&nbsp;0.2627R'&nbsp;+&nbsp;0.6780G'&nbsp;+&nbsp;0.0593B'</para>
<para>Cb&nbsp;=&nbsp;-0.1396R'&nbsp;-&nbsp;0.3604G'&nbsp;+&nbsp;0.5B'</para>
<para>Cr&nbsp;=&nbsp;0.5R'&nbsp;-&nbsp;0.4598G'&nbsp;-&nbsp;0.0402B'</para>
</listitem>
@ -1046,7 +1040,7 @@ clamped to the range [-0.5&hellip;0.5]. The Y'CbCr quantization is limited range
<varlistentry>
<term>Luma:</term>
<listitem>
<para>Yc'&nbsp;=&nbsp;(0.2627R&nbsp;+&nbsp;0.6789G&nbsp;+&nbsp;0.0593B)'</para>
<para>Yc'&nbsp;=&nbsp;(0.2627R&nbsp;+&nbsp;0.6780G&nbsp;+&nbsp;0.0593B)'</para>
</listitem>
</varlistentry>
</variablelist>
@ -1054,7 +1048,7 @@ clamped to the range [-0.5&hellip;0.5]. The Y'CbCr quantization is limited range
<varlistentry>
<term>B'&nbsp;-&nbsp;Yc'&nbsp;&le;&nbsp;0:</term>
<listitem>
<para>Cbc&nbsp;=&nbsp;(B'&nbsp;-&nbsp;Y')&nbsp;/&nbsp;1.9404</para>
<para>Cbc&nbsp;=&nbsp;(B'&nbsp;-&nbsp;Yc')&nbsp;/&nbsp;1.9404</para>
</listitem>
</varlistentry>
</variablelist>
@ -1062,7 +1056,7 @@ clamped to the range [-0.5&hellip;0.5]. The Y'CbCr quantization is limited range
<varlistentry>
<term>B'&nbsp;-&nbsp;Yc'&nbsp;&gt;&nbsp;0:</term>
<listitem>
<para>Cbc&nbsp;=&nbsp;(B'&nbsp;-&nbsp;Y')&nbsp;/&nbsp;1.5816</para>
<para>Cbc&nbsp;=&nbsp;(B'&nbsp;-&nbsp;Yc')&nbsp;/&nbsp;1.5816</para>
</listitem>
</varlistentry>
</variablelist>
@ -1086,8 +1080,8 @@ clamped to the range [-0.5&hellip;0.5]. The Y'CbCr quantization is limited range
clamped to the range [-0.5&hellip;0.5]. The Yc'CbcCrc quantization is limited range.</para>
</section>
<section>
<title id="col-smpte-240m">Colorspace SMPTE 240M (<constant>V4L2_COLORSPACE_SMPTE240M</constant>)</title>
<section id="col-smpte-240m">
<title>Colorspace SMPTE 240M (<constant>V4L2_COLORSPACE_SMPTE240M</constant>)</title>
<para>The <xref linkend="smpte240m" /> standard was an interim standard used during the early days of HDTV (1988-1998).
It has been superseded by Rec. 709. The default Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_SMPTE240M</constant>.
The default Y'CbCr quantization is limited range. The chromaticities of the primary colors and the
@ -1159,8 +1153,8 @@ following <constant>V4L2_YCBCR_ENC_SMPTE240M</constant> encoding:</term>
clamped to the range [-0.5&hellip;0.5]. The Y'CbCr quantization is limited range.</para>
</section>
<section>
<title id="col-sysm">Colorspace NTSC 1953 (<constant>V4L2_COLORSPACE_470_SYSTEM_M</constant>)</title>
<section id="col-sysm">
<title>Colorspace NTSC 1953 (<constant>V4L2_COLORSPACE_470_SYSTEM_M</constant>)</title>
<para>This standard defines the colorspace used by NTSC in 1953. In practice this
colorspace is obsolete and SMPTE 170M should be used instead. The default Y'CbCr encoding
is <constant>V4L2_YCBCR_ENC_601</constant>. The default Y'CbCr quantization is limited range.
@ -1237,8 +1231,8 @@ clamped to the range [-0.5&hellip;0.5]. The Y'CbCr quantization is limited range
This transform is identical to one defined in SMPTE 170M/BT.601.</para>
</section>
<section>
<title id="col-sysbg">Colorspace EBU Tech. 3213 (<constant>V4L2_COLORSPACE_470_SYSTEM_BG</constant>)</title>
<section id="col-sysbg">
<title>Colorspace EBU Tech. 3213 (<constant>V4L2_COLORSPACE_470_SYSTEM_BG</constant>)</title>
<para>The <xref linkend="tech3213" /> standard defines the colorspace used by PAL/SECAM in 1975. In practice this
colorspace is obsolete and SMPTE 170M should be used instead. The default Y'CbCr encoding
is <constant>V4L2_YCBCR_ENC_601</constant>. The default Y'CbCr quantization is limited range.
@ -1311,8 +1305,8 @@ clamped to the range [-0.5&hellip;0.5]. The Y'CbCr quantization is limited range
This transform is identical to one defined in SMPTE 170M/BT.601.</para>
</section>
<section>
<title id="col-jpeg">Colorspace JPEG (<constant>V4L2_COLORSPACE_JPEG</constant>)</title>
<section id="col-jpeg">
<title>Colorspace JPEG (<constant>V4L2_COLORSPACE_JPEG</constant>)</title>
<para>This colorspace defines the colorspace used by most (Motion-)JPEG formats. The chromaticities
of the primary colors and the white reference are identical to sRGB. The Y'CbCr encoding is
<constant>V4L2_YCBCR_ENC_601</constant> with full range quantization where

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9
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@ -136,6 +136,7 @@ Remote Controller chapter.</contrib>
<year>2012</year>
<year>2013</year>
<year>2014</year>
<year>2015</year>
<holder>Bill Dirks, Michael H. Schimek, Hans Verkuil, Martin
Rubli, Andy Walls, Muralidharan Karicheri, Mauro Carvalho Chehab,
Pawel Osciak</holder>
@ -151,6 +152,14 @@ structs, ioctls) must be noted in more detail in the history chapter
(compat.xml), along with the possible impact on existing drivers and
applications. -->
<revision>
<revnumber>3.21</revnumber>
<date>2015-02-13</date>
<authorinitials>mcc</authorinitials>
<revremark>Fix documentation for media controller device nodes and add support for DVB device nodes.
Add support for Tuner sub-device.
</revremark>
</revision>
<revision>
<revnumber>3.19</revnumber>
<date>2014-12-05</date>

9
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@ -59,6 +59,11 @@ constant except when switching the video standard. Remember this
switch can occur implicit when switching the video input or
output.</para>
<para>Do not use the multiplanar buffer types. Use <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>
instead of <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE</constant>
and use <constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant> instead of
<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE</constant>.</para>
<para>This ioctl must be implemented for video capture or output devices that
support cropping and/or scaling and/or have non-square pixels, and for overlay devices.</para>
@ -73,9 +78,7 @@ support cropping and/or scaling and/or have non-square pixels, and for overlay d
<entry>Type of the data stream, set by the application.
Only these types are valid here:
<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>,
<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE</constant>,
<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant>,
<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE</constant> and
<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant> and
<constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>. See <xref linkend="v4l2-buf-type" />.</entry>
</row>
<row>

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@ -64,7 +64,7 @@
<entry>__u32</entry>
<entry><structfield>type</structfield></entry>
<entry></entry>
<entry>Type of the event.</entry>
<entry>Type of the event, see <xref linkend="event-type" />.</entry>
</row>
<row>
<entry>union</entry>
@ -154,6 +154,113 @@
</tgroup>
</table>
<table frame="none" pgwide="1" id="event-type">
<title>Event Types</title>
<tgroup cols="3">
&cs-def;
<tbody valign="top">
<row>
<entry><constant>V4L2_EVENT_ALL</constant></entry>
<entry>0</entry>
<entry>All events. V4L2_EVENT_ALL is valid only for
VIDIOC_UNSUBSCRIBE_EVENT for unsubscribing all events at once.
</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_VSYNC</constant></entry>
<entry>1</entry>
<entry>This event is triggered on the vertical sync.
This event has a &v4l2-event-vsync; associated with it.
</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_EOS</constant></entry>
<entry>2</entry>
<entry>This event is triggered when the end of a stream is reached.
This is typically used with MPEG decoders to report to the application
when the last of the MPEG stream has been decoded.
</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_CTRL</constant></entry>
<entry>3</entry>
<entry><para>This event requires that the <structfield>id</structfield>
matches the control ID from which you want to receive events.
This event is triggered if the control's value changes, if a
button control is pressed or if the control's flags change.
This event has a &v4l2-event-ctrl; associated with it. This struct
contains much of the same information as &v4l2-queryctrl; and
&v4l2-control;.</para>
<para>If the event is generated due to a call to &VIDIOC-S-CTRL; or
&VIDIOC-S-EXT-CTRLS;, then the event will <emphasis>not</emphasis> be sent to
the file handle that called the ioctl function. This prevents
nasty feedback loops. If you <emphasis>do</emphasis> want to get the
event, then set the <constant>V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK</constant>
flag.
</para>
<para>This event type will ensure that no information is lost when
more events are raised than there is room internally. In that
case the &v4l2-event-ctrl; of the second-oldest event is kept,
but the <structfield>changes</structfield> field of the
second-oldest event is ORed with the <structfield>changes</structfield>
field of the oldest event.</para>
</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_FRAME_SYNC</constant></entry>
<entry>4</entry>
<entry>
<para>Triggered immediately when the reception of a
frame has begun. This event has a
&v4l2-event-frame-sync; associated with it.</para>
<para>If the hardware needs to be stopped in the case of a
buffer underrun it might not be able to generate this event.
In such cases the <structfield>frame_sequence</structfield>
field in &v4l2-event-frame-sync; will not be incremented. This
causes two consecutive frame sequence numbers to have n times
frame interval in between them.</para>
</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_SOURCE_CHANGE</constant></entry>
<entry>5</entry>
<entry>
<para>This event is triggered when a source parameter change is
detected during runtime by the video device. It can be a
runtime resolution change triggered by a video decoder or the
format change happening on an input connector.
This event requires that the <structfield>id</structfield>
matches the input index (when used with a video device node)
or the pad index (when used with a subdevice node) from which
you want to receive events.</para>
<para>This event has a &v4l2-event-src-change; associated
with it. The <structfield>changes</structfield> bitfield denotes
what has changed for the subscribed pad. If multiple events
occurred before application could dequeue them, then the changes
will have the ORed value of all the events generated.</para>
</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_MOTION_DET</constant></entry>
<entry>6</entry>
<entry>
<para>Triggered whenever the motion detection state for one or more of the regions
changes. This event has a &v4l2-event-motion-det; associated with it.</para>
</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_PRIVATE_START</constant></entry>
<entry>0x08000000</entry>
<entry>Base event number for driver-private events.</entry>
</row>
</tbody>
</tgroup>
</table>
<table frame="none" pgwide="1" id="v4l2-event-vsync">
<title>struct <structname>v4l2_event_vsync</structname></title>
<tgroup cols="3">
@ -177,7 +284,7 @@
<entry>__u32</entry>
<entry><structfield>changes</structfield></entry>
<entry></entry>
<entry>A bitmask that tells what has changed. See <xref linkend="changes-flags" />.</entry>
<entry>A bitmask that tells what has changed. See <xref linkend="ctrl-changes-flags" />.</entry>
</row>
<row>
<entry>__u32</entry>
@ -309,8 +416,8 @@
</tgroup>
</table>
<table pgwide="1" frame="none" id="changes-flags">
<title>Changes</title>
<table pgwide="1" frame="none" id="ctrl-changes-flags">
<title>Control Changes</title>
<tgroup cols="3">
&cs-def;
<tbody valign="top">
@ -318,9 +425,9 @@
<entry><constant>V4L2_EVENT_CTRL_CH_VALUE</constant></entry>
<entry>0x0001</entry>
<entry>This control event was triggered because the value of the control
changed. Special case: if a button control is pressed, then this
event is sent as well, even though there is not explicit value
associated with a button control.</entry>
changed. Special cases: Volatile controls do no generate this event;
If a control has the <constant>V4L2_CTRL_FLAG_EXECUTE_ON_WRITE</constant>
flag set, then this event is sent as well, regardless its value.</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_CTRL_CH_FLAGS</constant></entry>

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@ -70,6 +70,11 @@ structure or returns the &EINVAL; if cropping is not supported.</para>
<constant>VIDIOC_S_CROP</constant> ioctl with a pointer to this
structure.</para>
<para>Do not use the multiplanar buffer types. Use <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>
instead of <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE</constant>
and use <constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant> instead of
<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE</constant>.</para>
<para>The driver first adjusts the requested dimensions against
hardware limits, &ie; the bounds given by the capture/output window,
and it rounds to the closest possible values of horizontal and

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@ -318,10 +318,20 @@ can't generate such frequencies, then the flag will also be cleared.
</row>
<row>
<entry>V4L2_DV_FL_HALF_LINE</entry>
<entry>Specific to interlaced formats: if set, then field 1 (aka the odd field)
is really one half-line longer and field 2 (aka the even field) is really one half-line
shorter, so each field has exactly the same number of half-lines. Whether half-lines can be
detected or used depends on the hardware.
<entry>Specific to interlaced formats: if set, then the vertical frontporch
of field 1 (aka the odd field) is really one half-line longer and the vertical backporch
of field 2 (aka the even field) is really one half-line shorter, so each field has exactly
the same number of half-lines. Whether half-lines can be detected or used depends on
the hardware.
</entry>
</row>
<row>
<entry>V4L2_DV_FL_IS_CE_VIDEO</entry>
<entry>If set, then this is a Consumer Electronics (CE) video format.
Such formats differ from other formats (commonly called IT formats) in that if
R'G'B' encoding is used then by default the R'G'B' values use limited range
(i.e. 16-235) as opposed to full range (i.e. 0-255). All formats defined in CEA-861
except for the 640x480p59.94 format are CE formats.
</entry>
</row>
</tbody>

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@ -240,9 +240,9 @@ where padding bytes after the last line of an image cross a system
page boundary. Capture devices may write padding bytes, the value is
undefined. Output devices ignore the contents of padding
bytes.</para><para>When the image format is planar the
<structfield>bytesperline</structfield> value applies to the largest
<structfield>bytesperline</structfield> value applies to the first
plane and is divided by the same factor as the
<structfield>width</structfield> field for any smaller planes. For
<structfield>width</structfield> field for the other planes. For
example the Cb and Cr planes of a YUV 4:2:0 image have half as many
padding bytes following each line as the Y plane. To avoid ambiguities
drivers must return a <structfield>bytesperline</structfield> value

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@ -60,8 +60,8 @@
<para>To query the cropping (composing) rectangle set &v4l2-selection;
<structfield> type </structfield> field to the respective buffer type.
Do not use multiplanar buffers. Use <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>
instead of <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE</constant>. Use
Do not use the multiplanar buffer types. Use <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>
instead of <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE</constant> and use
<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant> instead of
<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE</constant>. The next step is
setting the value of &v4l2-selection; <structfield>target</structfield> field

2
Documentation/DocBook/media/v4l/vidioc-g-sliced-vbi-cap.xml
View File

@ -205,7 +205,7 @@ ETS&nbsp;300&nbsp;231, lsb first transmitted.</entry>
<row>
<entry><constant>V4L2_SLICED_CAPTION_525</constant></entry>
<entry>0x1000</entry>
<entry><xref linkend="eia608" /></entry>
<entry><xref linkend="cea608" /></entry>
<entry>NTSC line 21, 284 (second field 21)</entry>
<entry>Two bytes in transmission order, including parity
bit, lsb first transmitted.</entry>

8
Documentation/DocBook/media/v4l/vidioc-querycap.xml
View File

@ -102,10 +102,10 @@ The bus_info must start with "PCI:" for PCI boards, "PCIe:" for PCI Express boar
<entry>__u32</entry>
<entry><structfield>version</structfield></entry>
<entry><para>Version number of the driver.</para>
<para>Starting on kernel 3.1, the version reported is provided per
V4L2 subsystem, following the same Kernel numberation scheme. However, it
should not always return the same version as the kernel, if, for example,
an stable or distribution-modified kernel uses the V4L2 stack from a
<para>Starting with kernel 3.1, the version reported is provided by the
V4L2 subsystem following the kernel numbering scheme. However, it
may not always return the same version as the kernel if, for example,
a stable or distribution-modified kernel uses the V4L2 stack from a
newer kernel.</para>
<para>The version number is formatted using the
<constant>KERNEL_VERSION()</constant> macro:</para></entry>

12
Documentation/DocBook/media/v4l/vidioc-queryctrl.xml
View File

@ -600,7 +600,9 @@ writing a value will cause the device to carry out a given action
changes continuously. A typical example would be the current gain value if the device
is in auto-gain mode. In such a case the hardware calculates the gain value based on
the lighting conditions which can change over time. Note that setting a new value for
a volatile control will have no effect. The new value will just be ignored.</entry>
a volatile control will have no effect and no <constant>V4L2_EVENT_CTRL_CH_VALUE</constant>
will be sent, unless the <constant>V4L2_CTRL_FLAG_EXECUTE_ON_WRITE</constant> flag
(see below) is also set. Otherwise the new value will just be ignored.</entry>
</row>
<row>
<entry><constant>V4L2_CTRL_FLAG_HAS_PAYLOAD</constant></entry>
@ -610,6 +612,14 @@ using one of the pointer fields of &v4l2-ext-control;. This flag is set for cont
that are an array, string, or have a compound type. In all cases you have to set a
pointer to memory containing the payload of the control.</entry>
</row>
<row>
<entry><constant>V4L2_CTRL_FLAG_EXECUTE_ON_WRITE</constant></entry>
<entry>0x0200</entry>
<entry>The value provided to the control will be propagated to the driver
even if remains constant. This is required when the control represents an action
on the hardware. For example: clearing an error flag or triggering the flash. All the
controls of the type <constant>V4L2_CTRL_TYPE_BUTTON</constant> have this flag set.</entry>
</row>
</tbody>
</tgroup>
</table>

13
Documentation/DocBook/media/v4l/vidioc-subdev-enum-frame-interval.xml
View File

@ -67,9 +67,9 @@
<para>To enumerate frame intervals applications initialize the
<structfield>index</structfield>, <structfield>pad</structfield>,
<structfield>code</structfield>, <structfield>width</structfield> and
<structfield>height</structfield> fields of
&v4l2-subdev-frame-interval-enum; and call the
<structfield>which</structfield>, <structfield>code</structfield>,
<structfield>width</structfield> and <structfield>height</structfield>
fields of &v4l2-subdev-frame-interval-enum; and call the
<constant>VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL</constant> ioctl with a pointer
to this structure. Drivers fill the rest of the structure or return
an &EINVAL; if one of the input fields is invalid. All frame intervals are
@ -123,7 +123,12 @@
</row>
<row>
<entry>__u32</entry>
<entry><structfield>reserved</structfield>[9]</entry>
<entry><structfield>which</structfield></entry>
<entry>Frame intervals to be enumerated, from &v4l2-subdev-format-whence;.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>reserved</structfield>[8]</entry>
<entry>Reserved for future extensions. Applications and drivers must
set the array to zero.</entry>
</row>

13
Documentation/DocBook/media/v4l/vidioc-subdev-enum-frame-size.xml
View File

@ -61,9 +61,9 @@
ioctl.</para>
<para>To enumerate frame sizes applications initialize the
<structfield>pad</structfield>, <structfield>code</structfield> and
<structfield>index</structfield> fields of the
&v4l2-subdev-mbus-code-enum; and call the
<structfield>pad</structfield>, <structfield>which</structfield> ,
<structfield>code</structfield> and <structfield>index</structfield>
fields of the &v4l2-subdev-mbus-code-enum; and call the
<constant>VIDIOC_SUBDEV_ENUM_FRAME_SIZE</constant> ioctl with a pointer to
the structure. Drivers fill the minimum and maximum frame sizes or return
an &EINVAL; if one of the input parameters is invalid.</para>
@ -127,7 +127,12 @@
</row>
<row>
<entry>__u32</entry>
<entry><structfield>reserved</structfield>[9]</entry>
<entry><structfield>which</structfield></entry>
<entry>Frame sizes to be enumerated, from &v4l2-subdev-format-whence;.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>reserved</structfield>[8]</entry>
<entry>Reserved for future extensions. Applications and drivers must
set the array to zero.</entry>
</row>

11
Documentation/DocBook/media/v4l/vidioc-subdev-enum-mbus-code.xml
View File

@ -56,8 +56,8 @@
</note>
<para>To enumerate media bus formats available at a given sub-device pad
applications initialize the <structfield>pad</structfield> and
<structfield>index</structfield> fields of &v4l2-subdev-mbus-code-enum; and
applications initialize the <structfield>pad</structfield>, <structfield>which</structfield>
and <structfield>index</structfield> fields of &v4l2-subdev-mbus-code-enum; and
call the <constant>VIDIOC_SUBDEV_ENUM_MBUS_CODE</constant> ioctl with a
pointer to this structure. Drivers fill the rest of the structure or return
an &EINVAL; if either the <structfield>pad</structfield> or
@ -93,7 +93,12 @@
</row>
<row>
<entry>__u32</entry>
<entry><structfield>reserved</structfield>[9]</entry>
<entry><structfield>which</structfield></entry>
<entry>Media bus format codes to be enumerated, from &v4l2-subdev-format-whence;.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>reserved</structfield>[8]</entry>
<entry>Reserved for future extensions. Applications and drivers must
set the array to zero.</entry>
</row>

111
Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml
View File

@ -60,7 +60,9 @@
<row>
<entry>__u32</entry>
<entry><structfield>type</structfield></entry>
<entry>Type of the event.</entry>
<entry>Type of the event, see <xref linkend="event-type" />. Note that
<constant>V4L2_EVENT_ALL</constant> can be used with VIDIOC_UNSUBSCRIBE_EVENT
for unsubscribing all events at once.</entry>
</row>
<row>
<entry>__u32</entry>
@ -84,113 +86,6 @@
</tgroup>
</table>
<table frame="none" pgwide="1" id="event-type">
<title>Event Types</title>
<tgroup cols="3">
&cs-def;
<tbody valign="top">
<row>
<entry><constant>V4L2_EVENT_ALL</constant></entry>
<entry>0</entry>
<entry>All events. V4L2_EVENT_ALL is valid only for
VIDIOC_UNSUBSCRIBE_EVENT for unsubscribing all events at once.
</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_VSYNC</constant></entry>
<entry>1</entry>
<entry>This event is triggered on the vertical sync.
This event has a &v4l2-event-vsync; associated with it.
</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_EOS</constant></entry>
<entry>2</entry>
<entry>This event is triggered when the end of a stream is reached.
This is typically used with MPEG decoders to report to the application
when the last of the MPEG stream has been decoded.
</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_CTRL</constant></entry>
<entry>3</entry>
<entry><para>This event requires that the <structfield>id</structfield>
matches the control ID from which you want to receive events.
This event is triggered if the control's value changes, if a
button control is pressed or if the control's flags change.
This event has a &v4l2-event-ctrl; associated with it. This struct
contains much of the same information as &v4l2-queryctrl; and
&v4l2-control;.</para>
<para>If the event is generated due to a call to &VIDIOC-S-CTRL; or
&VIDIOC-S-EXT-CTRLS;, then the event will <emphasis>not</emphasis> be sent to
the file handle that called the ioctl function. This prevents
nasty feedback loops. If you <emphasis>do</emphasis> want to get the
event, then set the <constant>V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK</constant>
flag.
</para>
<para>This event type will ensure that no information is lost when
more events are raised than there is room internally. In that
case the &v4l2-event-ctrl; of the second-oldest event is kept,
but the <structfield>changes</structfield> field of the
second-oldest event is ORed with the <structfield>changes</structfield>
field of the oldest event.</para>
</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_FRAME_SYNC</constant></entry>
<entry>4</entry>
<entry>
<para>Triggered immediately when the reception of a
frame has begun. This event has a
&v4l2-event-frame-sync; associated with it.</para>
<para>If the hardware needs to be stopped in the case of a
buffer underrun it might not be able to generate this event.
In such cases the <structfield>frame_sequence</structfield>
field in &v4l2-event-frame-sync; will not be incremented. This
causes two consecutive frame sequence numbers to have n times
frame interval in between them.</para>
</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_SOURCE_CHANGE</constant></entry>
<entry>5</entry>
<entry>
<para>This event is triggered when a source parameter change is
detected during runtime by the video device. It can be a
runtime resolution change triggered by a video decoder or the
format change happening on an input connector.
This event requires that the <structfield>id</structfield>
matches the input index (when used with a video device node)
or the pad index (when used with a subdevice node) from which
you want to receive events.</para>
<para>This event has a &v4l2-event-src-change; associated
with it. The <structfield>changes</structfield> bitfield denotes
what has changed for the subscribed pad. If multiple events
occurred before application could dequeue them, then the changes
will have the ORed value of all the events generated.</para>
</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_MOTION_DET</constant></entry>
<entry>6</entry>
<entry>
<para>Triggered whenever the motion detection state for one or more of the regions
changes. This event has a &v4l2-event-motion-det; associated with it.</para>
</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_PRIVATE_START</constant></entry>
<entry>0x08000000</entry>
<entry>Base event number for driver-private events.</entry>
</row>
</tbody>
</tgroup>
</table>
<table pgwide="1" frame="none" id="event-flags">
<title>Event Flags</title>
<tgroup cols="3">

5
Documentation/IPMI.txt
View File

@ -505,7 +505,10 @@ at module load time (for a module) with:
The addresses are normal I2C addresses. The adapter is the string
name of the adapter, as shown in /sys/class/i2c-adapter/i2c-<n>/name.
It is *NOT* i2c-<n> itself.
It is *NOT* i2c-<n> itself. Also, the comparison is done ignoring
spaces, so if the name is "This is an I2C chip" you can say
adapter_name=ThisisanI2cchip. This is because it's hard to pass in
spaces in kernel parameters.
The debug flags are bit flags for each BMC found, they are:
IPMI messages: 1, driver state: 2, timing: 4, I2C probe: 8

3
Documentation/IRQ-domain.txt
View File

@ -95,8 +95,7 @@ since it doesn't need to allocate a table as large as the largest
hwirq number. The disadvantage is that hwirq to IRQ number lookup is
dependent on how many entries are in the table.
Very few drivers should need this mapping. At the moment, powerpc
iseries is the only user.
Very few drivers should need this mapping.
==== No Map ===-
irq_domain_add_nomap()

2
Documentation/Makefile
View File

@ -1,4 +1,4 @@
subdir-y := accounting arm auxdisplay blackfin connector \
subdir-y := accounting auxdisplay blackfin connector \
filesystems filesystems ia64 laptops mic misc-devices \
networking pcmcia prctl ptp spi timers vDSO video4linux \
watchdog

21
Documentation/PCI/MSI-HOWTO.txt
View File

@ -353,7 +353,7 @@ retry:
rc = pci_enable_msix_range(adapter->pdev, adapter->msix_entries,
maxvec, maxvec);
/*
* -ENOSPC is the only error code allowed to be analized
* -ENOSPC is the only error code allowed to be analyzed
*/
if (rc == -ENOSPC) {
if (maxvec == 1)
@ -370,7 +370,7 @@ retry:
return rc;
}
Note how pci_enable_msix_range() return value is analized for a fallback -
Note how pci_enable_msix_range() return value is analyzed for a fallback -
any error code other than -ENOSPC indicates a fatal error and should not
be retried.
@ -486,7 +486,7 @@ during development.
If your device supports both MSI-X and MSI capabilities, you should use
the MSI-X facilities in preference to the MSI facilities. As mentioned
above, MSI-X supports any number of interrupts between 1 and 2048.
In constrast, MSI is restricted to a maximum of 32 interrupts (and
In contrast, MSI is restricted to a maximum of 32 interrupts (and
must be a power of two). In addition, the MSI interrupt vectors must
be allocated consecutively, so the system might not be able to allocate
as many vectors for MSI as it could for MSI-X. On some platforms, MSI
@ -501,18 +501,9 @@ necessary to disable interrupts (Linux guarantees the same interrupt will
not be re-entered). If a device uses multiple interrupts, the driver
must disable interrupts while the lock is held. If the device sends
a different interrupt, the driver will deadlock trying to recursively
acquire the spinlock.
There are two solutions. The first is to take the lock with
spin_lock_irqsave() or spin_lock_irq() (see
Documentation/DocBook/kernel-locking). The second is to specify
IRQF_DISABLED to request_irq() so that the kernel runs the entire
interrupt routine with interrupts disabled.
If your MSI interrupt routine does not hold the lock for the whole time
it is running, the first solution may be best. The second solution is
normally preferred as it avoids making two transitions from interrupt
disabled to enabled and back again.
acquire the spinlock. Such deadlocks can be avoided by using
spin_lock_irqsave() or spin_lock_irq() which disable local interrupts
and acquire the lock (see Documentation/DocBook/kernel-locking).
4.6 How to tell whether MSI/MSI-X is enabled on a device

2
Documentation/PCI/pci-error-recovery.txt
View File

@ -256,7 +256,7 @@ STEP 4: Slot Reset
------------------
In response to a return value of PCI_ERS_RESULT_NEED_RESET, the
the platform will peform a slot reset on the requesting PCI device(s).
the platform will perform a slot reset on the requesting PCI device(s).
The actual steps taken by a platform to perform a slot reset
will be platform-dependent. Upon completion of slot reset, the
platform will call the device slot_reset() callback.

4
Documentation/PCI/pcieaer-howto.txt
View File

@ -66,8 +66,8 @@ hardware (mostly chipsets) has root ports that cannot obtain the reporting
source ID. nosourceid=n by default.
2.3 AER error output
When a PCI-E AER error is captured, an error message will be outputed to
console. If it's a correctable error, it is outputed as a warning.
When a PCI-E AER error is captured, an error message will be outputted to
console. If it's a correctable error, it is outputted as a warning.
Otherwise, it is printed as an error. So users could choose different
log level to filter out correctable error messages.

4
Documentation/SubmittingPatches
View File

@ -614,8 +614,8 @@ The canonical patch message body contains the following:
- An empty line.
- The body of the explanation, which will be copied to the
permanent changelog to describe this patch.
- The body of the explanation, line wrapped at 75 columns, which will
be copied to the permanent changelog to describe this patch.
- The "Signed-off-by:" lines, described above, which will
also go in the changelog.

28
Documentation/acpi/enumeration.txt
View File

@ -253,9 +253,14 @@ input driver:
GPIO support
~~~~~~~~~~~~
ACPI 5 introduced two new resources to describe GPIO connections: GpioIo
and GpioInt. These resources are used be used to pass GPIO numbers used by
the device to the driver. For example:
and GpioInt. These resources can be used to pass GPIO numbers used by
the device to the driver. ACPI 5.1 extended this with _DSD (Device
Specific Data) which made it possible to name the GPIOs among other things.
For example:
Device (DEV)
{
Method (_CRS, 0, NotSerialized)
{
Name (SBUF, ResourceTemplate()
@ -285,6 +290,18 @@ the device to the driver. For example:
Return (SBUF)
}
// ACPI 5.1 _DSD used for naming the GPIOs
Name (_DSD, Package ()
{
ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
Package ()
{
Package () {"power-gpios", Package() {^DEV, 0, 0, 0 }},
Package () {"irq-gpios", Package() {^DEV, 1, 0, 0 }},
}
})
...
These GPIO numbers are controller relative and path "\\_SB.PCI0.GPI0"
specifies the path to the controller. In order to use these GPIOs in Linux
we need to translate them to the corresponding Linux GPIO descriptors.
@ -300,11 +317,11 @@ a code like this:
struct gpio_desc *irq_desc, *power_desc;
irq_desc = gpiod_get_index(dev, NULL, 1);
irq_desc = gpiod_get(dev, "irq");
if (IS_ERR(irq_desc))
/* handle error */
power_desc = gpiod_get_index(dev, NULL, 0);
power_desc = gpiod_get(dev, "power");
if (IS_ERR(power_desc))
/* handle error */
@ -313,6 +330,9 @@ a code like this:
There are also devm_* versions of these functions which release the
descriptors once the device is released.
See Documentation/acpi/gpio-properties.txt for more information about the
_DSD binding related to GPIOs.
MFD devices
~~~~~~~~~~~
The MFD devices register their children as platform devices. For the child

6
Documentation/acpi/gpio-properties.txt
View File

@ -1,9 +1,9 @@
_DSD Device Properties Related to GPIO
--------------------------------------
With the release of ACPI 5.1 and the _DSD configuration objecte names
can finally be given to GPIOs (and other things as well) returned by
_CRS. Previously, we were only able to use an integer index to find
With the release of ACPI 5.1, the _DSD configuration object finally
allows names to be given to GPIOs (and other things as well) returned
by _CRS. Previously, we were only able to use an integer index to find
the corresponding GPIO, which is pretty error prone (it depends on
the _CRS output ordering, for example).

2
Documentation/arm/00-INDEX
View File

@ -10,8 +10,6 @@ IXP4xx
- Intel IXP4xx Network processor.
Makefile
- Build sourcefiles as part of the Documentation-build for arm
msm/
- MSM specific documentation
Netwinder
- Netwinder specific documentation
Porting

9
Documentation/arm/Booting
View File

@ -58,13 +58,18 @@ serial format options as described in
--------------------------
Existing boot loaders: OPTIONAL
New boot loaders: MANDATORY
New boot loaders: MANDATORY except for DT-only platforms
The boot loader should detect the machine type its running on by some
method. Whether this is a hard coded value or some algorithm that
looks at the connected hardware is beyond the scope of this document.
The boot loader must ultimately be able to provide a MACH_TYPE_xxx
value to the kernel. (see linux/arch/arm/tools/mach-types).
value to the kernel. (see linux/arch/arm/tools/mach-types). This
should be passed to the kernel in register r1.
For DT-only platforms, the machine type will be determined by device
tree. set the machine type to all ones (~0). This is not strictly
necessary, but assures that it will not match any existing types.
4. Setup boot data
------------------

1
Documentation/arm/Makefile
View File

@ -1 +0,0 @@
subdir-y := SH-Mobile

5
Documentation/arm/Marvell/README
View File

@ -96,6 +96,11 @@ EBU Armada family
88F6820
88F6828
Armada 390/398 Flavors:
88F6920
88F6928
Product infos: http://www.marvell.com/embedded-processors/armada-39x/
Armada XP Flavors:
MV78230
MV78260

15
Documentation/arm/README
View File

@ -185,13 +185,20 @@ Kernel entry (head.S)
board devices are used, or the device is setup, and provides that
machine specific "personality."
This fine-grained machine specific selection is controlled by the machine
type ID, which acts both as a run-time and a compile-time code selection
method.
For platforms that support device tree (DT), the machine selection is
controlled at runtime by passing the device tree blob to the kernel. At
compile-time, support for the machine type must be selected. This allows for
a single multiplatform kernel build to be used for several machine types.
You can register a new machine via the web site at:
For platforms that do not use device tree, this machine selection is
controlled by the machine type ID, which acts both as a run-time and a
compile-time code selection method. You can register a new machine via the
web site at:
<http://www.arm.linux.org.uk/developer/machines/>
Note: Please do not register a machine type for DT-only platforms. If your
platform is DT-only, you do not need a registered machine type.
---
Russell King (15/03/2004)

7
Documentation/arm/SH-Mobile/Makefile
View File

@ -1,7 +0,0 @@
# List of programs to build
hostprogs-y := vrl4
# Tell kbuild to always build the programs
always := $(hostprogs-y)
HOSTCFLAGS_vrl4.o += -I$(objtree)/usr/include -I$(srctree)/tools/include

170
Documentation/arm/SH-Mobile/vrl4.c
View File

@ -1,170 +0,0 @@
/*
* vrl4 format generator
*
* Copyright (C) 2010 Simon Horman
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
/*
* usage: vrl4 < zImage > out
* dd if=out of=/dev/sdx bs=512 seek=1 # Write the image to sector 1
*
* Reads a zImage from stdin and writes a vrl4 image to stdout.
* In practice this means writing a padded vrl4 header to stdout followed
* by the zImage.
*
* The padding places the zImage at ALIGN bytes into the output.
* The vrl4 uses ALIGN + START_BASE as the start_address.
* This is where the mask ROM will jump to after verifying the header.
*
* The header sets copy_size to min(sizeof(zImage), MAX_BOOT_PROG_LEN) + ALIGN.
* That is, the mask ROM will load the padded header (ALIGN bytes)
* And then MAX_BOOT_PROG_LEN bytes of the image, or the entire image,
* whichever is smaller.
*
* The zImage is not modified in any way.
*/
#define _BSD_SOURCE
#include <endian.h>
#include <unistd.h>
#include <stdint.h>
#include <stdio.h>
#include <errno.h>
#include <tools/endian.h>
struct hdr {
uint32_t magic1;
uint32_t reserved1;
uint32_t magic2;
uint32_t reserved2;
uint16_t copy_size;
uint16_t boot_options;
uint32_t reserved3;
uint32_t start_address;
uint32_t reserved4;
uint32_t reserved5;
char reserved6[308];
};
#define DECLARE_HDR(h) \
struct hdr (h) = { \
.magic1 = htole32(0xea000000), \
.reserved1 = htole32(0x56), \
.magic2 = htole32(0xe59ff008), \
.reserved3 = htole16(0x1) }
/* Align to 512 bytes, the MMCIF sector size */
#define ALIGN_BITS 9
#define ALIGN (1 << ALIGN_BITS)
#define START_BASE 0xe55b0000
/*
* With an alignment of 512 the header uses the first sector.
* There is a 128 sector (64kbyte) limit on the data loaded by the mask ROM.
* So there are 127 sectors left for the boot programme. But in practice
* Only a small portion of a zImage is needed, 16 sectors should be more
* than enough.
*
* Note that this sets how much of the zImage is copied by the mask ROM.
* The entire zImage is present after the header and is loaded
* by the code in the boot program (which is the first portion of the zImage).
*/
#define MAX_BOOT_PROG_LEN (16 * 512)
#define ROUND_UP(x) ((x + ALIGN - 1) & ~(ALIGN - 1))
static ssize_t do_read(int fd, void *buf, size_t count)
{
size_t offset = 0;
ssize_t l;
while (offset < count) {
l = read(fd, buf + offset, count - offset);
if (!l)
break;
if (l < 0) {
if (errno == EAGAIN || errno == EWOULDBLOCK)
continue;
perror("read");
return -1;
}
offset += l;
}
return offset;
}
static ssize_t do_write(int fd, const void *buf, size_t count)
{
size_t offset = 0;
ssize_t l;
while (offset < count) {
l = write(fd, buf + offset, count - offset);
if (l < 0) {
if (errno == EAGAIN || errno == EWOULDBLOCK)
continue;
perror("write");
return -1;
}
offset += l;
}
return offset;
}
static ssize_t write_zero(int fd, size_t len)
{
size_t i = len;
while (i--) {
const char x = 0;
if (do_write(fd, &x, 1) < 0)
return -1;
}
return len;
}
int main(void)
{
DECLARE_HDR(hdr);
char boot_program[MAX_BOOT_PROG_LEN];
size_t aligned_hdr_len, alligned_prog_len;
ssize_t prog_len;
prog_len = do_read(0, boot_program, sizeof(boot_program));
if (prog_len <= 0)
return -1;
aligned_hdr_len = ROUND_UP(sizeof(hdr));
hdr.start_address = htole32(START_BASE + aligned_hdr_len);
alligned_prog_len = ROUND_UP(prog_len);
hdr.copy_size = htole16(aligned_hdr_len + alligned_prog_len);
if (do_write(1, &hdr, sizeof(hdr)) < 0)
return -1;
if (write_zero(1, aligned_hdr_len - sizeof(hdr)) < 0)
return -1;
if (do_write(1, boot_program, prog_len) < 0)
return 1;
/* Write out the rest of the kernel */
while (1) {
prog_len = do_read(0, boot_program, sizeof(boot_program));
if (prog_len < 0)
return 1;
if (prog_len == 0)
break;
if (do_write(1, boot_program, prog_len) < 0)
return 1;
}
return 0;
}

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ROM-able zImage boot from MMC
-----------------------------
An ROM-able zImage compiled with ZBOOT_ROM_MMCIF may be written to MMC and
SuperH Mobile ARM will to boot directly from the MMCIF hardware block.
This is achieved by the mask ROM loading the first portion of the image into
MERAM and then jumping to it. This portion contains loader code which
copies the entire image to SDRAM and jumps to it. From there the zImage
boot code proceeds as normal, uncompressing the image into its final
location and then jumping to it.
This code has been tested on an AP4EB board using the developer 1A eMMC
boot mode which is configured using the following jumper settings.
The board used for testing required a patched mask ROM in order for
this mode to function.
8 7 6 5 4 3 2 1
x|x|x|x|x| |x|
S4 -+-+-+-+-+-+-+-
| | | | |x| |x on
The zImage must be written to the MMC card at sector 1 (512 bytes) in
vrl4 format. A utility vrl4 is supplied to accomplish this.
e.g.
vrl4 < zImage | dd of=/dev/sdX bs=512 seek=1
A dual-voltage MMC 4.0 card was used for testing.

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ROM-able zImage boot from eSD
-----------------------------
An ROM-able zImage compiled with ZBOOT_ROM_SDHI may be written to eSD and
SuperH Mobile ARM will to boot directly from the SDHI hardware block.
This is achieved by the mask ROM loading the first portion of the image into
MERAM and then jumping to it. This portion contains loader code which
copies the entire image to SDRAM and jumps to it. From there the zImage
boot code proceeds as normal, uncompressing the image into its final
location and then jumping to it.
This code has been tested on an mackerel board using the developer 1A eSD
boot mode which is configured using the following jumper settings.
8 7 6 5 4 3 2 1
x|x|x|x| |x|x|
S4 -+-+-+-+-+-+-+-
| | | |x| | |x on
The eSD card needs to be present in SDHI slot 1 (CN7).
As such S1 and S33 also need to be configured as per
the notes in arch/arm/mach-shmobile/board-mackerel.c.
A partial zImage must be written to physical partition #1 (boot)
of the eSD at sector 0 in vrl4 format. A utility vrl4 is supplied to
accomplish this.
e.g.
vrl4 < zImage | dd of=/dev/sdX bs=512 count=17
A full copy of _the same_ zImage should be written to physical partition #1
(boot) of the eSD at sector 0. This should _not_ be in vrl4 format.
vrl4 < zImage | dd of=/dev/sdX bs=512
Note: The commands above assume that the physical partition has been
switched. No such facility currently exists in the Linux Kernel.
Physical partitions are described in the eSD specification. At the time of
writing they are not the same as partitions that are typically configured
using fdisk and visible through /proc/partitions

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This document provides an overview of the msm_gpiomux interface, which
is used to provide gpio pin multiplexing and configuration on mach-msm
targets.
History
=======
The first-generation API for gpio configuration & multiplexing on msm
is the function gpio_tlmm_config(). This function has a few notable
shortcomings, which led to its deprecation and replacement by gpiomux:
The 'disable' parameter: Setting the second parameter to
gpio_tlmm_config to GPIO_CFG_DISABLE tells the peripheral
processor in charge of the subsystem to perform a look-up into a
low-power table and apply the low-power/sleep setting for the pin.
As the msm family evolved this became problematic. Not all pins
have sleep settings, not all peripheral processors will accept requests
to apply said sleep settings, and not all msm targets have their gpio
subsystems managed by a peripheral processor. In order to get consistent
behavior on all targets, drivers are forced to ignore this parameter,
rendering it useless.
The 'direction' flag: for all mux-settings other than raw-gpio (0),
the output-enable bit of a gpio is hard-wired to a known
input (usually VDD or ground). For those settings, the direction flag
is meaningless at best, and deceptive at worst. In addition, using the
direction flag to change output-enable (OE) directly can cause trouble in
gpiolib, which has no visibility into gpio direction changes made
in this way. Direction control in gpio mode should be made through gpiolib.
Key Features of gpiomux
=======================
- A consistent interface across all generations of msm. Drivers can expect
the same results on every target.
- gpiomux plays nicely with gpiolib. Functions that should belong to gpiolib
are left to gpiolib and not duplicated here. gpiomux is written with the
intent that gpio_chips will call gpiomux reference-counting methods
from their request() and free() hooks, providing full integration.
- Tabular configuration. Instead of having to call gpio_tlmm_config
hundreds of times, gpio configuration is placed in a single table.
- Per-gpio sleep. Each gpio is individually reference counted, allowing only
those lines which are in use to be put in high-power states.
- 0 means 'do nothing': all flags are designed so that the default memset-zero
equates to a sensible default of 'no configuration', preventing users
from having to provide hundreds of 'no-op' configs for unused or
unwanted lines.
Usage
=====
To use gpiomux, provide configuration information for relevant gpio lines
in the msm_gpiomux_configs table. Since a 0 equates to "unconfigured",
only those lines to be managed by gpiomux need to be specified. Here
is a completely fictional example:
struct msm_gpiomux_config msm_gpiomux_configs[GPIOMUX_NGPIOS] = {
[12] = {
.active = GPIOMUX_VALID | GPIOMUX_DRV_8MA | GPIOMUX_FUNC_1,
.suspended = GPIOMUX_VALID | GPIOMUX_PULL_DOWN,
},
[34] = {
.suspended = GPIOMUX_VALID | GPIOMUX_PULL_DOWN,
},
};
To indicate that a gpio is in use, call msm_gpiomux_get() to increase
its reference count. To decrease the reference count, call msm_gpiomux_put().
The effect of this configuration is as follows:
When the system boots, gpios 12 and 34 will be initialized with their
'suspended' configurations. All other gpios, which were left unconfigured,
will not be touched.
When msm_gpiomux_get() is called on gpio 12 to raise its reference count
above 0, its active configuration will be applied. Since no other gpio
line has a valid active configuration, msm_gpiomux_get() will have no
effect on any other line.
When msm_gpiomux_put() is called on gpio 12 or 34 to drop their reference
count to 0, their suspended configurations will be applied.
Since no other gpio line has a valid suspended configuration, no other
gpio line will be effected by msm_gpiomux_put(). Since gpio 34 has no valid
active configuration, this is effectively a no-op for gpio 34 as well,
with one small caveat, see the section "About Output-Enable Settings".
All of the GPIOMUX_VALID flags may seem like unnecessary overhead, but
they address some important issues. As unused entries (all those
except 12 and 34) are zero-filled, gpiomux needs a way to distinguish
the used fields from the unused. In addition, the all-zero pattern
is a valid configuration! Therefore, gpiomux defines an additional bit
which is used to indicate when a field is used. This has the pleasant
side-effect of allowing calls to msm_gpiomux_write to use '0' to indicate
that a value should not be changed:
msm_gpiomux_write(0, GPIOMUX_VALID, 0);
replaces the active configuration of gpio 0 with an all-zero configuration,
but leaves the suspended configuration as it was.
Static Configurations
=====================
To install a static configuration, which is applied at boot and does
not change after that, install a configuration with a suspended component
but no active component, as in the previous example:
[34] = {
.suspended = GPIOMUX_VALID | GPIOMUX_PULL_DOWN,
},
The suspended setting is applied during boot, and the lack of any valid
active setting prevents any other setting from being applied at runtime.
If other subsystems attempting to access the line is a concern, one could
*really* anchor the configuration down by calling msm_gpiomux_get on the
line at initialization to move the line into active mode. With the line
held, it will never be re-suspended, and with no valid active configuration,
no new configurations will be applied.
But then, if having other subsystems grabbing for the line is truly a concern,
it should be reserved with gpio_request instead, which carries an implicit
msm_gpiomux_get.
gpiomux and gpiolib
===================
It is expected that msm gpio_chips will call msm_gpiomux_get() and
msm_gpiomux_put() from their request and free hooks, like this fictional
example:
static int request(struct gpio_chip *chip, unsigned offset)
{
return msm_gpiomux_get(chip->base + offset);
}
static void free(struct gpio_chip *chip, unsigned offset)
{
msm_gpiomux_put(chip->base + offset);
}
...somewhere in a gpio_chip declaration...
.request = request,
.free = free,
This provides important functionality:
- It guarantees that a gpio line will have its 'active' config applied
when the line is requested, and will not be suspended while the line
remains requested; and
- It guarantees that gpio-direction settings from gpiolib behave sensibly.
See "About Output-Enable Settings."
This mechanism allows for "auto-request" of gpiomux lines via gpiolib
when it is suitable. Drivers wishing more exact control are, of course,
free to also use msm_gpiomux_set and msm_gpiomux_get.
About Output-Enable Settings
============================
Some msm targets do not have the ability to query the current gpio
configuration setting. This means that changes made to the output-enable
(OE) bit by gpiolib cannot be consistently detected and preserved by gpiomux.
Therefore, when gpiomux applies a configuration setting, any direction
settings which may have been applied by gpiolib are lost and the default
input settings are re-applied.
For this reason, drivers should not assume that gpio direction settings
continue to hold if they free and then re-request a gpio. This seems like
common sense - after all, anybody could have obtained the line in the
meantime - but it needs saying.
This also means that calls to msm_gpiomux_write will reset the OE bit,
which means that if the gpio line is held by a client of gpiolib and
msm_gpiomux_write is called, the direction setting has been lost and
gpiolib's internal state has been broken.
Release gpio lines before reconfiguring them.

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ACPI Tables
-----------
The expectations of individual ACPI tables are discussed in the list that
follows.
If a section number is used, it refers to a section number in the ACPI
specification where the object is defined. If "Signature Reserved" is used,
the table signature (the first four bytes of the table) is the only portion
of the table recognized by the specification, and the actual table is defined
outside of the UEFI Forum (see Section 5.2.6 of the specification).
For ACPI on arm64, tables also fall into the following categories:
-- Required: DSDT, FADT, GTDT, MADT, MCFG, RSDP, SPCR, XSDT
-- Recommended: BERT, EINJ, ERST, HEST, SSDT
-- Optional: BGRT, CPEP, CSRT, DRTM, ECDT, FACS, FPDT, MCHI, MPST,
MSCT, RASF, SBST, SLIT, SPMI, SRAT, TCPA, TPM2, UEFI
-- Not supported: BOOT, DBG2, DBGP, DMAR, ETDT, HPET, IBFT, IVRS,
LPIT, MSDM, RSDT, SLIC, WAET, WDAT, WDRT, WPBT
Table Usage for ARMv8 Linux
----- ----------------------------------------------------------------
BERT Section 18.3 (signature == "BERT")
== Boot Error Record Table ==
Must be supplied if RAS support is provided by the platform. It
is recommended this table be supplied.
BOOT Signature Reserved (signature == "BOOT")
== simple BOOT flag table ==
Microsoft only table, will not be supported.
BGRT Section 5.2.22 (signature == "BGRT")
== Boot Graphics Resource Table ==
Optional, not currently supported, with no real use-case for an
ARM server.
CPEP Section 5.2.18 (signature == "CPEP")
== Corrected Platform Error Polling table ==
Optional, not currently supported, and not recommended until such
time as ARM-compatible hardware is available, and the specification
suitably modified.
CSRT Signature Reserved (signature == "CSRT")
== Core System Resources Table ==
Optional, not currently supported.
DBG2 Signature Reserved (signature == "DBG2")
== DeBuG port table 2 ==
Microsoft only table, will not be supported.
DBGP Signature Reserved (signature == "DBGP")
== DeBuG Port table ==
Microsoft only table, will not be supported.
DSDT Section 5.2.11.1 (signature == "DSDT")
== Differentiated System Description Table ==
A DSDT is required; see also SSDT.
ACPI tables contain only one DSDT but can contain one or more SSDTs,
which are optional. Each SSDT can only add to the ACPI namespace,
but cannot modify or replace anything in the DSDT.
DMAR Signature Reserved (signature == "DMAR")
== DMA Remapping table ==
x86 only table, will not be supported.
DRTM Signature Reserved (signature == "DRTM")
== Dynamic Root of Trust for Measurement table ==
Optional, not currently supported.
ECDT Section 5.2.16 (signature == "ECDT")
== Embedded Controller Description Table ==
Optional, not currently supported, but could be used on ARM if and
only if one uses the GPE_BIT field to represent an IRQ number, since
there are no GPE blocks defined in hardware reduced mode. This would
need to be modified in the ACPI specification.
EINJ Section 18.6 (signature == "EINJ")
== Error Injection table ==
This table is very useful for testing platform response to error
conditions; it allows one to inject an error into the system as
if it had actually occurred. However, this table should not be
shipped with a production system; it should be dynamically loaded
and executed with the ACPICA tools only during testing.
ERST Section 18.5 (signature == "ERST")
== Error Record Serialization Table ==
On a platform supports RAS, this table must be supplied if it is not
UEFI-based; if it is UEFI-based, this table may be supplied. When this
table is not present, UEFI run time service will be utilized to save
and retrieve hardware error information to and from a persistent store.
ETDT Signature Reserved (signature == "ETDT")
== Event Timer Description Table ==
Obsolete table, will not be supported.
FACS Section 5.2.10 (signature == "FACS")
== Firmware ACPI Control Structure ==
It is unlikely that this table will be terribly useful. If it is
provided, the Global Lock will NOT be used since it is not part of
the hardware reduced profile, and only 64-bit address fields will
be considered valid.
FADT Section 5.2.9 (signature == "FACP")
== Fixed ACPI Description Table ==
Required for arm64.
The HW_REDUCED_ACPI flag must be set. All of the fields that are
to be ignored when HW_REDUCED_ACPI is set are expected to be set to
zero.
If an FACS table is provided, the X_FIRMWARE_CTRL field is to be
used, not FIRMWARE_CTRL.
If PSCI is used (as is recommended), make sure that ARM_BOOT_ARCH is
filled in properly -- that the PSCI_COMPLIANT flag is set and that
PSCI_USE_HVC is set or unset as needed (see table 5-37).
For the DSDT that is also required, the X_DSDT field is to be used,
not the DSDT field.
FPDT Section 5.2.23 (signature == "FPDT")
== Firmware Performance Data Table ==
Optional, not currently supported.
GTDT Section 5.2.24 (signature == "GTDT")
== Generic Timer Description Table ==
Required for arm64.
HEST Section 18.3.2 (signature == "HEST")
== Hardware Error Source Table ==
Until further error source types are defined, use only types 6 (AER
Root Port), 7 (AER Endpoint), 8 (AER Bridge), or 9 (Generic Hardware
Error Source). Firmware first error handling is possible if and only
if Trusted Firmware is being used on arm64.
Must be supplied if RAS support is provided by the platform. It
is recommended this table be supplied.
HPET Signature Reserved (signature == "HPET")
== High Precision Event timer Table ==
x86 only table, will not be supported.
IBFT Signature Reserved (signature == "IBFT")
== iSCSI Boot Firmware Table ==
Microsoft defined table, support TBD.
IVRS Signature Reserved (signature == "IVRS")
== I/O Virtualization Reporting Structure ==
x86_64 (AMD) only table, will not be supported.
LPIT Signature Reserved (signature == "LPIT")
== Low Power Idle Table ==
x86 only table as of ACPI 5.1; future versions have been adapted for
use with ARM and will be recommended in order to support ACPI power
management.
MADT Section 5.2.12 (signature == "APIC")
== Multiple APIC Description Table ==
Required for arm64. Only the GIC interrupt controller structures
should be used (types 0xA - 0xE).
MCFG Signature Reserved (signature == "MCFG")
== Memory-mapped ConFiGuration space ==
If the platform supports PCI/PCIe, an MCFG table is required.
MCHI Signature Reserved (signature == "MCHI")
== Management Controller Host Interface table ==
Optional, not currently supported.
MPST Section 5.2.21 (signature == "MPST")
== Memory Power State Table ==
Optional, not currently supported.
MSDM Signature Reserved (signature == "MSDM")
== Microsoft Data Management table ==
Microsoft only table, will not be supported.
MSCT Section 5.2.19 (signature == "MSCT")
== Maximum System Characteristic Table ==
Optional, not currently supported.
RASF Section 5.2.20 (signature == "RASF")
== RAS Feature table ==
Optional, not currently supported.
RSDP Section 5.2.5 (signature == "RSD PTR")
== Root System Description PoinTeR ==
Required for arm64.
RSDT Section 5.2.7 (signature == "RSDT")
== Root System Description Table ==
Since this table can only provide 32-bit addresses, it is deprecated
on arm64, and will not be used.
SBST Section 5.2.14 (signature == "SBST")
== Smart Battery Subsystem Table ==
Optional, not currently supported.
SLIC Signature Reserved (signature == "SLIC")
== Software LIcensing table ==
Microsoft only table, will not be supported.
SLIT Section 5.2.17 (signature == "SLIT")
== System Locality distance Information Table ==
Optional in general, but required for NUMA systems.
SPCR Signature Reserved (signature == "SPCR")
== Serial Port Console Redirection table ==
Required for arm64.
SPMI Signature Reserved (signature == "SPMI")
== Server Platform Management Interface table ==
Optional, not currently supported.
SRAT Section 5.2.16 (signature == "SRAT")
== System Resource Affinity Table ==
Optional, but if used, only the GICC Affinity structures are read.
To support NUMA, this table is required.
SSDT Section 5.2.11.2 (signature == "SSDT")
== Secondary System Description Table ==
These tables are a continuation of the DSDT; these are recommended
for use with devices that can be added to a running system, but can
also serve the purpose of dividing up device descriptions into more
manageable pieces.
An SSDT can only ADD to the ACPI namespace. It cannot modify or
replace existing device descriptions already in the namespace.
These tables are optional, however. ACPI tables should contain only
one DSDT but can contain many SSDTs.
TCPA Signature Reserved (signature == "TCPA")
== Trusted Computing Platform Alliance table ==
Optional, not currently supported, and may need changes to fully
interoperate with arm64.
TPM2 Signature Reserved (signature == "TPM2")
== Trusted Platform Module 2 table ==
Optional, not currently supported, and may need changes to fully
interoperate with arm64.
UEFI Signature Reserved (signature == "UEFI")
== UEFI ACPI data table ==
Optional, not currently supported. No known use case for arm64,
at present.
WAET Signature Reserved (signature == "WAET")
== Windows ACPI Emulated devices Table ==
Microsoft only table, will not be supported.
WDAT Signature Reserved (signature == "WDAT")
== Watch Dog Action Table ==
Microsoft only table, will not be supported.
WDRT Signature Reserved (signature == "WDRT")
== Watch Dog Resource Table ==
Microsoft only table, will not be supported.
WPBT Signature Reserved (signature == "WPBT")
== Windows Platform Binary Table ==
Microsoft only table, will not be supported.
XSDT Section 5.2.8 (signature == "XSDT")
== eXtended System Description Table ==
Required for arm64.
ACPI Objects
------------
The expectations on individual ACPI objects are discussed in the list that
follows:
Name Section Usage for ARMv8 Linux
---- ------------ -------------------------------------------------
_ADR 6.1.1 Use as needed.
_BBN 6.5.5 Use as needed; PCI-specific.
_BDN 6.5.3 Optional; not likely to be used on arm64.
_CCA 6.2.17 This method should be defined for all bus masters
on arm64. While cache coherency is assumed, making
it explicit ensures the kernel will set up DMA as
it should.
_CDM 6.2.1 Optional, to be used only for processor devices.
_CID 6.1.2 Use as needed.
_CLS 6.1.3 Use as needed.
_CRS 6.2.2 Required on arm64.
_DCK 6.5.2 Optional; not likely to be used on arm64.
_DDN 6.1.4 This field can be used for a device name. However,
it is meant for DOS device names (e.g., COM1), so be
careful of its use across OSes.
_DEP 6.5.8 Use as needed.
_DIS 6.2.3 Optional, for power management use.
_DLM 5.7.5 Optional.
_DMA 6.2.4 Optional.
_DSD 6.2.5 To be used with caution. If this object is used, try
to use it within the constraints already defined by the
Device Properties UUID. Only in rare circumstances
should it be necessary to create a new _DSD UUID.
In either case, submit the _DSD definition along with
any driver patches for discussion, especially when
device properties are used. A driver will not be
considered complete without a corresponding _DSD
description. Once approved by kernel maintainers,
the UUID or device properties must then be registered
with the UEFI Forum; this may cause some iteration as
more than one OS will be registering entries.
_DSM Do not use this method. It is not standardized, the
return values are not well documented, and it is
currently a frequent source of error.
_DSW 7.2.1 Use as needed; power management specific.
_EDL 6.3.1 Optional.
_EJD 6.3.2 Optional.
_EJx 6.3.3 Optional.
_FIX 6.2.7 x86 specific, not used on arm64.
\_GL 5.7.1 This object is not to be used in hardware reduced
mode, and therefore should not be used on arm64.
_GLK 6.5.7 This object requires a global lock be defined; there
is no global lock on arm64 since it runs in hardware
reduced mode. Hence, do not use this object on arm64.
\_GPE 5.3.1 This namespace is for x86 use only. Do not use it
on arm64.
_GSB 6.2.7 Optional.
_HID 6.1.5 Use as needed. This is the primary object to use in
device probing, though _CID and _CLS may also be used.
_HPP 6.2.8 Optional, PCI specific.
_HPX 6.2.9 Optional, PCI specific.
_HRV 6.1.6 Optional, use as needed to clarify device behavior; in
some cases, this may be easier to use than _DSD.
_INI 6.5.1 Not required, but can be useful in setting up devices
when UEFI leaves them in a state that may not be what
the driver expects before it starts probing.
_IRC 7.2.15 Use as needed; power management specific.
_LCK 6.3.4 Optional.
_MAT 6.2.10 Optional; see also the MADT.
_MLS 6.1.7 Optional, but highly recommended for use in
internationalization.
_OFF 7.1.2 It is recommended to define this method for any device
that can be turned on or off.
_ON 7.1.3 It is recommended to define this method for any device
that can be turned on or off.
\_OS 5.7.3 This method will return "Linux" by default (this is
the value of the macro ACPI_OS_NAME on Linux). The
command line parameter acpi_os=<string> can be used
to set it to some other value.
_OSC 6.2.11 This method can be a global method in ACPI (i.e.,
\_SB._OSC), or it may be associated with a specific
device (e.g., \_SB.DEV0._OSC), or both. When used
as a global method, only capabilities published in
the ACPI specification are allowed. When used as
a device-specific method, the process described for
using _DSD MUST be used to create an _OSC definition;
out-of-process use of _OSC is not allowed. That is,
submit the device-specific _OSC usage description as
part of the kernel driver submission, get it approved
by the kernel community, then register it with the
UEFI Forum.
\_OSI 5.7.2 Deprecated on ARM64. Any invocation of this method
will print a warning on the console and return false.
That is, as far as ACPI firmware is concerned, _OSI
cannot be used to determine what sort of system is
being used or what functionality is provided. The
_OSC method is to be used instead.
_OST 6.3.5 Optional.
_PDC 8.4.1 Deprecated, do not use on arm64.
\_PIC 5.8.1 The method should not be used. On arm64, the only
interrupt model available is GIC.
_PLD 6.1.8 Optional.
\_PR 5.3.1 This namespace is for x86 use only on legacy systems.
Do not use it on arm64.
_PRS 6.2.12 Optional.
_PRT 6.2.13 Required as part of the definition of all PCI root
devices.
_PRW 7.2.13 Use as needed; power management specific.
_PRx 7.2.8-11 Use as needed; power management specific. If _PR0 is
defined, _PR3 must also be defined.
_PSC 7.2.6 Use as needed; power management specific.
_PSE 7.2.7 Use as needed; power management specific.
_PSW 7.2.14 Use as needed; power management specific.
_PSx 7.2.2-5 Use as needed; power management specific. If _PS0 is
defined, _PS3 must also be defined. If clocks or
regulators need adjusting to be consistent with power
usage, change them in these methods.
\_PTS 7.3.1 Use as needed; power management specific.
_PXM 6.2.14 Optional.
_REG 6.5.4 Use as needed.
\_REV 5.7.4 Always returns the latest version of ACPI supported.
_RMV 6.3.6 Optional.
\_SB 5.3.1 Required on arm64; all devices must be defined in this
namespace.
_SEG 6.5.6 Use as needed; PCI-specific.
\_SI 5.3.1, Optional.
9.1
_SLI 6.2.15 Optional; recommended when SLIT table is in use.
_STA 6.3.7, It is recommended to define this method for any device
7.1.4 that can be turned on or off.
_SRS 6.2.16 Optional; see also _PRS.
_STR 6.1.10 Recommended for conveying device names to end users;
this is preferred over using _DDN.
_SUB 6.1.9 Use as needed; _HID or _CID are preferred.
_SUN 6.1.11 Optional.
\_Sx 7.3.2 Use as needed; power management specific.
_SxD 7.2.16-19 Use as needed; power management specific.
_SxW 7.2.20-24 Use as needed; power management specific.
_SWS 7.3.3 Use as needed; power management specific; this may
require specification changes for use on arm64.
\_TTS 7.3.4 Use as needed; power management specific.
\_TZ 5.3.1 Optional.
_UID 6.1.12 Recommended for distinguishing devices of the same
class; define it if at all possible.
\_WAK 7.3.5 Use as needed; power management specific.
ACPI Event Model
----------------
Do not use GPE block devices; these are not supported in the hardware reduced
profile used by arm64. Since there are no GPE blocks defined for use on ARM
platforms, GPIO-signaled interrupts should be used for creating system events.
ACPI Processor Control
----------------------
Section 8 of the ACPI specification is currently undergoing change that
should be completed in the 6.0 version of the specification. Processor
performance control will be handled differently for arm64 at that point
in time. Processor aggregator devices (section 8.5) will not be used,
for example, but another similar mechanism instead.
While UEFI constrains what we can say until the release of 6.0, it is
recommended that CPPC (8.4.5) be used as the primary model. This will
still be useful into the future. C-states and P-states will still be
provided, but most of the current design work appears to favor CPPC.
Further, it is essential that the ARMv8 SoC provide a fully functional
implementation of PSCI; this will be the only mechanism supported by ACPI
to control CPU power state (including secondary CPU booting).
More details will be provided on the release of the ACPI 6.0 specification.
ACPI System Address Map Interfaces
----------------------------------
In Section 15 of the ACPI specification, several methods are mentioned as
possible mechanisms for conveying memory resource information to the kernel.
For arm64, we will only support UEFI for booting with ACPI, hence the UEFI
GetMemoryMap() boot service is the only mechanism that will be used.
ACPI Platform Error Interfaces (APEI)
-------------------------------------
The APEI tables supported are described above.
APEI requires the equivalent of an SCI and an NMI on ARMv8. The SCI is used
to notify the OSPM of errors that have occurred but can be corrected and the
system can continue correct operation, even if possibly degraded. The NMI is
used to indicate fatal errors that cannot be corrected, and require immediate
attention.
Since there is no direct equivalent of the x86 SCI or NMI, arm64 handles
these slightly differently. The SCI is handled as a normal GPIO-signaled
interrupt; given that these are corrected (or correctable) errors being
reported, this is sufficient. The NMI is emulated as the highest priority
GPIO-signaled interrupt possible. This implies some caution must be used
since there could be interrupts at higher privilege levels or even interrupts
at the same priority as the emulated NMI. In Linux, this should not be the
case but one should be aware it could happen.
ACPI Objects Not Supported on ARM64
-----------------------------------
While this may change in the future, there are several classes of objects
that can be defined, but are not currently of general interest to ARM servers.
These are not supported:
-- Section 9.2: ambient light sensor devices
-- Section 9.3: battery devices
-- Section 9.4: lids (e.g., laptop lids)
-- Section 9.8.2: IDE controllers
-- Section 9.9: floppy controllers
-- Section 9.10: GPE block devices
-- Section 9.15: PC/AT RTC/CMOS devices
-- Section 9.16: user presence detection devices
-- Section 9.17: I/O APIC devices; all GICs must be enumerable via MADT
-- Section 9.18: time and alarm devices (see 9.15)
ACPI Objects Not Yet Implemented
--------------------------------
While these objects have x86 equivalents, and they do make some sense in ARM
servers, there is either no hardware available at present, or in some cases
there may not yet be a non-ARM implementation. Hence, they are currently not
implemented though that may change in the future.
Not yet implemented are:
-- Section 10: power source and power meter devices
-- Section 11: thermal management
-- Section 12: embedded controllers interface
-- Section 13: SMBus interfaces
-- Section 17: NUMA support (prototypes have been submitted for
review)

505
Documentation/arm64/arm-acpi.txt 100644
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@ -0,0 +1,505 @@
ACPI on ARMv8 Servers
---------------------
ACPI can be used for ARMv8 general purpose servers designed to follow
the ARM SBSA (Server Base System Architecture) [0] and SBBR (Server
Base Boot Requirements) [1] specifications. Please note that the SBBR
can be retrieved simply by visiting [1], but the SBSA is currently only
available to those with an ARM login due to ARM IP licensing concerns.
The ARMv8 kernel implements the reduced hardware model of ACPI version
5.1 or later. Links to the specification and all external documents
it refers to are managed by the UEFI Forum. The specification is
available at http://www.uefi.org/specifications and documents referenced
by the specification can be found via http://www.uefi.org/acpi.
If an ARMv8 system does not meet the requirements of the SBSA and SBBR,
or cannot be described using the mechanisms defined in the required ACPI
specifications, then ACPI may not be a good fit for the hardware.
While the documents mentioned above set out the requirements for building
industry-standard ARMv8 servers, they also apply to more than one operating
system. The purpose of this document is to describe the interaction between
ACPI and Linux only, on an ARMv8 system -- that is, what Linux expects of
ACPI and what ACPI can expect of Linux.
Why ACPI on ARM?
----------------
Before examining the details of the interface between ACPI and Linux, it is
useful to understand why ACPI is being used. Several technologies already
exist in Linux for describing non-enumerable hardware, after all. In this
section we summarize a blog post [2] from Grant Likely that outlines the
reasoning behind ACPI on ARMv8 servers. Actually, we snitch a good portion
of the summary text almost directly, to be honest.
The short form of the rationale for ACPI on ARM is:
-- ACPI’s bytecode (AML) allows the platform to encode hardware behavior,
while DT explicitly does not support this. For hardware vendors, being
able to encode behavior is a key tool used in supporting operating
system releases on new hardware.
-- ACPI’s OSPM defines a power management model that constrains what the
platform is allowed to do into a specific model, while still providing
flexibility in hardware design.
-- In the enterprise server environment, ACPI has established bindings (such
as for RAS) which are currently used in production systems. DT does not.
Such bindings could be defined in DT at some point, but doing so means ARM
and x86 would end up using completely different code paths in both firmware
and the kernel.
-- Choosing a single interface to describe the abstraction between a platform
and an OS is important. Hardware vendors would not be required to implement
both DT and ACPI if they want to support multiple operating systems. And,
agreeing on a single interface instead of being fragmented into per OS
interfaces makes for better interoperability overall.
-- The new ACPI governance process works well and Linux is now at the same
table as hardware vendors and other OS vendors. In fact, there is no
longer any reason to feel that ACPI is only belongs to Windows or that
Linux is in any way secondary to Microsoft in this arena. The move of
ACPI governance into the UEFI forum has significantly opened up the
specification development process, and currently, a large portion of the
changes being made to ACPI is being driven by Linux.
Key to the use of ACPI is the support model. For servers in general, the
responsibility for hardware behaviour cannot solely be the domain of the
kernel, but rather must be split between the platform and the kernel, in
order to allow for orderly change over time. ACPI frees the OS from needing
to understand all the minute details of the hardware so that the OS doesn’t
need to be ported to each and every device individually. It allows the
hardware vendors to take responsibility for power management behaviour without
depending on an OS release cycle which is not under their control.
ACPI is also important because hardware and OS vendors have already worked
out the mechanisms for supporting a general purpose computing ecosystem. The
infrastructure is in place, the bindings are in place, and the processes are
in place. DT does exactly what Linux needs it to when working with vertically
integrated devices, but there are no good processes for supporting what the
server vendors need. Linux could potentially get there with DT, but doing so
really just duplicates something that already works. ACPI already does what
the hardware vendors need, Microsoft won’t collaborate on DT, and hardware
vendors would still end up providing two completely separate firmware
interfaces -- one for Linux and one for Windows.
Kernel Compatibility
--------------------
One of the primary motivations for ACPI is standardization, and using that
to provide backward compatibility for Linux kernels. In the server market,
software and hardware are often used for long periods. ACPI allows the
kernel and firmware to agree on a consistent abstraction that can be
maintained over time, even as hardware or software change. As long as the
abstraction is supported, systems can be updated without necessarily having
to replace the kernel.
When a Linux driver or subsystem is first implemented using ACPI, it by
definition ends up requiring a specific version of the ACPI specification
-- it's baseline. ACPI firmware must continue to work, even though it may
not be optimal, with the earliest kernel version that first provides support
for that baseline version of ACPI. There may be a need for additional drivers,
but adding new functionality (e.g., CPU power management) should not break
older kernel versions. Further, ACPI firmware must also work with the most
recent version of the kernel.
Relationship with Device Tree
-----------------------------
ACPI support in drivers and subsystems for ARMv8 should never be mutually
exclusive with DT support at compile time.
At boot time the kernel will only use one description method depending on
parameters passed from the bootloader (including kernel bootargs).
Regardless of whether DT or ACPI is used, the kernel must always be capable
of booting with either scheme (in kernels with both schemes enabled at compile
time).
Booting using ACPI tables
-------------------------
The only defined method for passing ACPI tables to the kernel on ARMv8
is via the UEFI system configuration table. Just so it is explicit, this
means that ACPI is only supported on platforms that boot via UEFI.
When an ARMv8 system boots, it can either have DT information, ACPI tables,
or in some very unusual cases, both. If no command line parameters are used,
the kernel will try to use DT for device enumeration; if there is no DT
present, the kernel will try to use ACPI tables, but only if they are present.
In neither is available, the kernel will not boot. If acpi=force is used
on the command line, the kernel will attempt to use ACPI tables first, but
fall back to DT if there are no ACPI tables present. The basic idea is that
the kernel will not fail to boot unless it absolutely has no other choice.
Processing of ACPI tables may be disabled by passing acpi=off on the kernel
command line; this is the default behavior.
In order for the kernel to load and use ACPI tables, the UEFI implementation
MUST set the ACPI_20_TABLE_GUID to point to the RSDP table (the table with
the ACPI signature "RSD PTR "). If this pointer is incorrect and acpi=force
is used, the kernel will disable ACPI and try to use DT to boot instead; the
kernel has, in effect, determined that ACPI tables are not present at that
point.
If the pointer to the RSDP table is correct, the table will be mapped into
the kernel by the ACPI core, using the address provided by UEFI.
The ACPI core will then locate and map in all other ACPI tables provided by
using the addresses in the RSDP table to find the XSDT (eXtended System
Description Table). The XSDT in turn provides the addresses to all other
ACPI tables provided by the system firmware; the ACPI core will then traverse
this table and map in the tables listed.
The ACPI core will ignore any provided RSDT (Root System Description Table).
RSDTs have been deprecated and are ignored on arm64 since they only allow
for 32-bit addresses.
Further, the ACPI core will only use the 64-bit address fields in the FADT
(Fixed ACPI Description Table). Any 32-bit address fields in the FADT will
be ignored on arm64.
Hardware reduced mode (see Section 4.1 of the ACPI 5.1 specification) will
be enforced by the ACPI core on arm64. Doing so allows the ACPI core to
run less complex code since it no longer has to provide support for legacy
hardware from other architectures. Any fields that are not to be used for
hardware reduced mode must be set to zero.
For the ACPI core to operate properly, and in turn provide the information
the kernel needs to configure devices, it expects to find the following
tables (all section numbers refer to the ACPI 5.1 specfication):
-- RSDP (Root System Description Pointer), section 5.2.5
-- XSDT (eXtended System Description Table), section 5.2.8
-- FADT (Fixed ACPI Description Table), section 5.2.9
-- DSDT (Differentiated System Description Table), section
5.2.11.1
-- MADT (Multiple APIC Description Table), section 5.2.12
-- GTDT (Generic Timer Description Table), section 5.2.24
-- If PCI is supported, the MCFG (Memory mapped ConFiGuration
Table), section 5.2.6, specifically Table 5-31.
If the above tables are not all present, the kernel may or may not be
able to boot properly since it may not be able to configure all of the
devices available.
ACPI Detection
--------------
Drivers should determine their probe() type by checking for a null
value for ACPI_HANDLE, or checking .of_node, or other information in
the device structure. This is detailed further in the "Driver
Recommendations" section.
In non-driver code, if the presence of ACPI needs to be detected at
runtime, then check the value of acpi_disabled. If CONFIG_ACPI is not
set, acpi_disabled will always be 1.
Device Enumeration
------------------
Device descriptions in ACPI should use standard recognized ACPI interfaces.
These may contain less information than is typically provided via a Device
Tree description for the same device. This is also one of the reasons that
ACPI can be useful -- the driver takes into account that it may have less
detailed information about the device and uses sensible defaults instead.
If done properly in the driver, the hardware can change and improve over
time without the driver having to change at all.
Clocks provide an excellent example. In DT, clocks need to be specified
and the drivers need to take them into account. In ACPI, the assumption
is that UEFI will leave the device in a reasonable default state, including
any clock settings. If for some reason the driver needs to change a clock
value, this can be done in an ACPI method; all the driver needs to do is
invoke the method and not concern itself with what the method needs to do
to change the clock. Changing the hardware can then take place over time
by changing what the ACPI method does, and not the driver.
In DT, the parameters needed by the driver to set up clocks as in the example
above are known as "bindings"; in ACPI, these are known as "Device Properties"
and provided to a driver via the _DSD object.
ACPI tables are described with a formal language called ASL, the ACPI
Source Language (section 19 of the specification). This means that there
are always multiple ways to describe the same thing -- including device
properties. For example, device properties could use an ASL construct
that looks like this: Name(KEY0, "value0"). An ACPI device driver would
then retrieve the value of the property by evaluating the KEY0 object.
However, using Name() this way has multiple problems: (1) ACPI limits
names ("KEY0") to four characters unlike DT; (2) there is no industry
wide registry that maintains a list of names, minimzing re-use; (3)
there is also no registry for the definition of property values ("value0"),
again making re-use difficult; and (4) how does one maintain backward
compatibility as new hardware comes out? The _DSD method was created
to solve precisely these sorts of problems; Linux drivers should ALWAYS
use the _DSD method for device properties and nothing else.
The _DSM object (ACPI Section 9.14.1) could also be used for conveying
device properties to a driver. Linux drivers should only expect it to
be used if _DSD cannot represent the data required, and there is no way
to create a new UUID for the _DSD object. Note that there is even less
regulation of the use of _DSM than there is of _DSD. Drivers that depend
on the contents of _DSM objects will be more difficult to maintain over
time because of this; as of this writing, the use of _DSM is the cause
of quite a few firmware problems and is not recommended.
Drivers should look for device properties in the _DSD object ONLY; the _DSD
object is described in the ACPI specification section 6.2.5, but this only
describes how to define the structure of an object returned via _DSD, and
how specific data structures are defined by specific UUIDs. Linux should
only use the _DSD Device Properties UUID [5]:
-- UUID: daffd814-6eba-4d8c-8a91-bc9bbf4aa301
-- http://www.uefi.org/sites/default/files/resources/_DSD-device-properties-UUID.pdf
The UEFI Forum provides a mechanism for registering device properties [4]
so that they may be used across all operating systems supporting ACPI.
Device properties that have not been registered with the UEFI Forum should
not be used.
Before creating new device properties, check to be sure that they have not
been defined before and either registered in the Linux kernel documentation
as DT bindings, or the UEFI Forum as device properties. While we do not want
to simply move all DT bindings into ACPI device properties, we can learn from
what has been previously defined.
If it is necessary to define a new device property, or if it makes sense to
synthesize the definition of a binding so it can be used in any firmware,
both DT bindings and ACPI device properties for device drivers have review
processes. Use them both. When the driver itself is submitted for review
to the Linux mailing lists, the device property definitions needed must be
submitted at the same time. A driver that supports ACPI and uses device
properties will not be considered complete without their definitions. Once
the device property has been accepted by the Linux community, it must be
registered with the UEFI Forum [4], which will review it again for consistency
within the registry. This may require iteration. The UEFI Forum, though,
will always be the canonical site for device property definitions.
It may make sense to provide notice to the UEFI Forum that there is the
intent to register a previously unused device property name as a means of
reserving the name for later use. Other operating system vendors will
also be submitting registration requests and this may help smooth the
process.
Once registration and review have been completed, the kernel provides an
interface for looking up device properties in a manner independent of
whether DT or ACPI is being used. This API should be used [6]; it can
eliminate some duplication of code paths in driver probing functions and
discourage divergence between DT bindings and ACPI device properties.
Programmable Power Control Resources
------------------------------------
Programmable power control resources include such resources as voltage/current
providers (regulators) and clock sources.
With ACPI, the kernel clock and regulator framework is not expected to be used
at all.
The kernel assumes that power control of these resources is represented with
Power Resource Objects (ACPI section 7.1). The ACPI core will then handle
correctly enabling and disabling resources as they are needed. In order to
get that to work, ACPI assumes each device has defined D-states and that these
can be controlled through the optional ACPI methods _PS0, _PS1, _PS2, and _PS3;
in ACPI, _PS0 is the method to invoke to turn a device full on, and _PS3 is for
turning a device full off.
There are two options for using those Power Resources. They can:
-- be managed in a _PSx method which gets called on entry to power
state Dx.
-- be declared separately as power resources with their own _ON and _OFF
methods. They are then tied back to D-states for a particular device
via _PRx which specifies which power resources a device needs to be on
while in Dx. Kernel then tracks number of devices using a power resource
and calls _ON/_OFF as needed.
The kernel ACPI code will also assume that the _PSx methods follow the normal
ACPI rules for such methods:
-- If either _PS0 or _PS3 is implemented, then the other method must also
be implemented.
-- If a device requires usage or setup of a power resource when on, the ASL
should organize that it is allocated/enabled using the _PS0 method.
-- Resources allocated or enabled in the _PS0 method should be disabled
or de-allocated in the _PS3 method.
-- Firmware will leave the resources in a reasonable state before handing
over control to the kernel.
Such code in _PSx methods will of course be very platform specific. But,
this allows the driver to abstract out the interface for operating the device
and avoid having to read special non-standard values from ACPI tables. Further,
abstracting the use of these resources allows the hardware to change over time
without requiring updates to the driver.
Clocks
------
ACPI makes the assumption that clocks are initialized by the firmware --
UEFI, in this case -- to some working value before control is handed over
to the kernel. This has implications for devices such as UARTs, or SoC-driven
LCD displays, for example.
When the kernel boots, the clocks are assumed to be set to reasonable
working values. If for some reason the frequency needs to change -- e.g.,
throttling for power management -- the device driver should expect that
process to be abstracted out into some ACPI method that can be invoked
(please see the ACPI specification for further recommendations on standard
methods to be expected). The only exceptions to this are CPU clocks where
CPPC provides a much richer interface than ACPI methods. If the clocks
are not set, there is no direct way for Linux to control them.
If an SoC vendor wants to provide fine-grained control of the system clocks,
they could do so by providing ACPI methods that could be invoked by Linux
drivers. However, this is NOT recommended and Linux drivers should NOT use
such methods, even if they are provided. Such methods are not currently
standardized in the ACPI specification, and using them could tie a kernel
to a very specific SoC, or tie an SoC to a very specific version of the
kernel, both of which we are trying to avoid.
Driver Recommendations
----------------------
DO NOT remove any DT handling when adding ACPI support for a driver. The
same device may be used on many different systems.
DO try to structure the driver so that it is data-driven. That is, set up
a struct containing internal per-device state based on defaults and whatever
else must be discovered by the driver probe function. Then, have the rest
of the driver operate off of the contents of that struct. Doing so should
allow most divergence between ACPI and DT functionality to be kept local to
the probe function instead of being scattered throughout the driver. For
example:
static int device_probe_dt(struct platform_device *pdev)
{
/* DT specific functionality */
...
}
static int device_probe_acpi(struct platform_device *pdev)
{
/* ACPI specific functionality */
...
}
static int device_probe(struct platform_device *pdev)
{
...
struct device_node node = pdev->dev.of_node;
...
if (node)
ret = device_probe_dt(pdev);
else if (ACPI_HANDLE(&pdev->dev))
ret = device_probe_acpi(pdev);
else
/* other initialization */
...
/* Continue with any generic probe operations */
...
}
DO keep the MODULE_DEVICE_TABLE entries together in the driver to make it
clear the different names the driver is probed for, both from DT and from
ACPI:
static struct of_device_id virtio_mmio_match[] = {
{ .compatible = "virtio,mmio", },
{ }
};
MODULE_DEVICE_TABLE(of, virtio_mmio_match);
static const struct acpi_device_id virtio_mmio_acpi_match[] = {
{ "LNRO0005", },
{ }
};
MODULE_DEVICE_TABLE(acpi, virtio_mmio_acpi_match);
ASWG
----
The ACPI specification changes regularly. During the year 2014, for instance,
version 5.1 was released and version 6.0 substantially completed, with most of
the changes being driven by ARM-specific requirements. Proposed changes are
presented and discussed in the ASWG (ACPI Specification Working Group) which
is a part of the UEFI Forum.
Participation in this group is open to all UEFI members. Please see
http://www.uefi.org/workinggroup for details on group membership.
It is the intent of the ARMv8 ACPI kernel code to follow the ACPI specification
as closely as possible, and to only implement functionality that complies with
the released standards from UEFI ASWG. As a practical matter, there will be
vendors that provide bad ACPI tables or violate the standards in some way.
If this is because of errors, quirks and fixups may be necessary, but will
be avoided if possible. If there are features missing from ACPI that preclude
it from being used on a platform, ECRs (Engineering Change Requests) should be
submitted to ASWG and go through the normal approval process; for those that
are not UEFI members, many other members of the Linux community are and would
likely be willing to assist in submitting ECRs.
Linux Code
----------
Individual items specific to Linux on ARM, contained in the the Linux
source code, are in the list that follows:
ACPI_OS_NAME This macro defines the string to be returned when
an ACPI method invokes the _OS method. On ARM64
systems, this macro will be "Linux" by default.
The command line parameter acpi_os=<string>
can be used to set it to some other value. The
default value for other architectures is "Microsoft
Windows NT", for example.
ACPI Objects
------------
Detailed expectations for ACPI tables and object are listed in the file
Documentation/arm64/acpi_object_usage.txt.
References
----------
[0] http://silver.arm.com -- document ARM-DEN-0029, or newer
"Server Base System Architecture", version 2.3, dated 27 Mar 2014
[1] http://infocenter.arm.com/help/topic/com.arm.doc.den0044a/Server_Base_Boot_Requirements.pdf
Document ARM-DEN-0044A, or newer: "Server Base Boot Requirements, System
Software on ARM Platforms", dated 16 Aug 2014
[2] http://www.secretlab.ca/archives/151, 10 Jan 2015, Copyright (c) 2015,
Linaro Ltd., written by Grant Likely. A copy of the verbatim text (apart
from formatting) is also in Documentation/arm64/why_use_acpi.txt.
[3] AMD ACPI for Seattle platform documentation:
http://amd-dev.wpengine.netdna-cdn.com/wordpress/media/2012/10/Seattle_ACPI_Guide.pdf
[4] http://www.uefi.org/acpi -- please see the link for the "ACPI _DSD Device
Property Registry Instructions"
[5] http://www.uefi.org/acpi -- please see the link for the "_DSD (Device
Specific Data) Implementation Guide"
[6] Kernel code for the unified device property interface can be found in
include/linux/property.h and drivers/base/property.c.
Authors
-------
Al Stone <al.stone@linaro.org>
Graeme Gregory <graeme.gregory@linaro.org>
Hanjun Guo <hanjun.guo@linaro.org>
Grant Likely <grant.likely@linaro.org>, for the "Why ACPI on ARM?" section

45
Documentation/atomic_ops.txt
View File

@ -201,11 +201,11 @@ These routines add 1 and subtract 1, respectively, from the given
atomic_t and return the new counter value after the operation is
performed.
Unlike the above routines, it is required that explicit memory
barriers are performed before and after the operation. It must be
done such that all memory operations before and after the atomic
operation calls are strongly ordered with respect to the atomic
operation itself.
Unlike the above routines, it is required that these primitives
include explicit memory barriers that are performed before and after
the operation. It must be done such that all memory operations before
and after the atomic operation calls are strongly ordered with respect
to the atomic operation itself.
For example, it should behave as if a smp_mb() call existed both
before and after the atomic operation.
@ -233,21 +233,21 @@ These two routines increment and decrement by 1, respectively, the
given atomic counter. They return a boolean indicating whether the
resulting counter value was zero or not.
It requires explicit memory barrier semantics around the operation as
above.
Again, these primitives provide explicit memory barrier semantics around
the atomic operation.
int atomic_sub_and_test(int i, atomic_t *v);
This is identical to atomic_dec_and_test() except that an explicit
decrement is given instead of the implicit "1". It requires explicit
memory barrier semantics around the operation.
decrement is given instead of the implicit "1". This primitive must
provide explicit memory barrier semantics around the operation.
int atomic_add_negative(int i, atomic_t *v);
The given increment is added to the given atomic counter value. A
boolean is return which indicates whether the resulting counter value
is negative. It requires explicit memory barrier semantics around the
operation.
The given increment is added to the given atomic counter value. A boolean
is return which indicates whether the resulting counter value is negative.
This primitive must provide explicit memory barrier semantics around
the operation.
Then:
@ -257,7 +257,7 @@ This performs an atomic exchange operation on the atomic variable v, setting
the given new value. It returns the old value that the atomic variable v had
just before the operation.
atomic_xchg requires explicit memory barriers around the operation.
atomic_xchg must provide explicit memory barriers around the operation.
int atomic_cmpxchg(atomic_t *v, int old, int new);
@ -266,7 +266,7 @@ with the given old and new values. Like all atomic_xxx operations,
atomic_cmpxchg will only satisfy its atomicity semantics as long as all
other accesses of *v are performed through atomic_xxx operations.
atomic_cmpxchg requires explicit memory barriers around the operation.
atomic_cmpxchg must provide explicit memory barriers around the operation.
The semantics for atomic_cmpxchg are the same as those defined for 'cas'
below.
@ -279,8 +279,8 @@ If the atomic value v is not equal to u, this function adds a to v, and
returns non zero. If v is equal to u then it returns zero. This is done as
an atomic operation.
atomic_add_unless requires explicit memory barriers around the operation
unless it fails (returns 0).
atomic_add_unless must provide explicit memory barriers around the
operation unless it fails (returns 0).
atomic_inc_not_zero, equivalent to atomic_add_unless(v, 1, 0)
@ -460,9 +460,9 @@ the return value into an int. There are other places where things
like this occur as well.
These routines, like the atomic_t counter operations returning values,
require explicit memory barrier semantics around their execution. All
memory operations before the atomic bit operation call must be made
visible globally before the atomic bit operation is made visible.
must provide explicit memory barrier semantics around their execution.
All memory operations before the atomic bit operation call must be
made visible globally before the atomic bit operation is made visible.
Likewise, the atomic bit operation must be visible globally before any
subsequent memory operation is made visible. For example:
@ -536,8 +536,9 @@ except that two underscores are prefixed to the interface name.
These non-atomic variants also do not require any special memory
barrier semantics.
The routines xchg() and cmpxchg() need the same exact memory barriers
as the atomic and bit operations returning values.
The routines xchg() and cmpxchg() must provide the same exact
memory-barrier semantics as the atomic and bit operations returning
values.
Spinlocks and rwlocks have memory barrier expectations as well.
The rule to follow is simple:

2
Documentation/blackfin/Makefile
View File

@ -1,5 +1,5 @@
ifneq ($(CONFIG_BLACKFIN),)
ifneq ($(CONFIG_BFIN_GPTIMERS,)
ifneq ($(CONFIG_BFIN_GPTIMERS),)
obj-m := gptimers-example.o
endif
endif

34
Documentation/block/biodoc.txt
View File

@ -48,8 +48,7 @@ Description of Contents:
- Highmem I/O support
- I/O scheduler modularization
1.2 Tuning based on high level requirements/capabilities
1.2.1 I/O Barriers
1.2.2 Request Priority/Latency
1.2.1 Request Priority/Latency
1.3 Direct access/bypass to lower layers for diagnostics and special
device operations
1.3.1 Pre-built commands
@ -255,29 +254,12 @@ some control over i/o ordering.
What kind of support exists at the generic block layer for this ?
The flags and rw fields in the bio structure can be used for some tuning
from above e.g indicating that an i/o is just a readahead request, or for
marking barrier requests (discussed next), or priority settings (currently
unused). As far as user applications are concerned they would need an
additional mechanism either via open flags or ioctls, or some other upper
level mechanism to communicate such settings to block.
from above e.g indicating that an i/o is just a readahead request, or priority
settings (currently unused). As far as user applications are concerned they
would need an additional mechanism either via open flags or ioctls, or some
other upper level mechanism to communicate such settings to block.
1.2.1 I/O Barriers
There is a way to enforce strict ordering for i/os through barriers.
All requests before a barrier point must be serviced before the barrier
request and any other requests arriving after the barrier will not be
serviced until after the barrier has completed. This is useful for higher
level control on write ordering, e.g flushing a log of committed updates
to disk before the corresponding updates themselves.
A flag in the bio structure, BIO_BARRIER is used to identify a barrier i/o.
The generic i/o scheduler would make sure that it places the barrier request and
all other requests coming after it after all the previous requests in the
queue. Barriers may be implemented in different ways depending on the
driver. For more details regarding I/O barriers, please read barrier.txt
in this directory.
1.2.2 Request Priority/Latency
1.2.1 Request Priority/Latency
Todo/Under discussion:
Arjan's proposed request priority scheme allows higher levels some broad
@ -906,8 +888,8 @@ queue and specific I/O schedulers. Unless stated otherwise, elevator is used
to refer to both parts and I/O scheduler to specific I/O schedulers.
Block layer implements generic dispatch queue in block/*.c.
The generic dispatch queue is responsible for properly ordering barrier
requests, requeueing, handling non-fs requests and all other subtleties.
The generic dispatch queue is responsible for requeueing, handling non-fs
requests and all other subtleties.
Specific I/O schedulers are responsible for ordering normal filesystem
requests. They can also choose to delay certain requests to improve

44
Documentation/blockdev/nbd.txt
View File

@ -1,17 +1,31 @@
Network Block Device (TCP version)
What is it: With this compiled in the kernel (or as a module), Linux
can use a remote server as one of its block devices. So every time
the client computer wants to read, e.g., /dev/nb0, it sends a
request over TCP to the server, which will reply with the data read.
This can be used for stations with low disk space (or even diskless)
to borrow disk space from another computer.
Unlike NFS, it is possible to put any filesystem on it, etc.
Network Block Device (TCP version)
==================================
For more information, or to download the nbd-client and nbd-server
tools, go to http://nbd.sf.net/.
1) Overview
-----------
What is it: With this compiled in the kernel (or as a module), Linux
can use a remote server as one of its block devices. So every time
the client computer wants to read, e.g., /dev/nb0, it sends a
request over TCP to the server, which will reply with the data read.
This can be used for stations with low disk space (or even diskless)
to borrow disk space from another computer.
Unlike NFS, it is possible to put any filesystem on it, etc.
For more information, or to download the nbd-client and nbd-server
tools, go to http://nbd.sf.net/.
The nbd kernel module need only be installed on the client
system, as the nbd-server is completely in userspace. In fact,
the nbd-server has been successfully ported to other operating
systems, including Windows.
A) NBD parameters
-----------------
max_part
Number of partitions per device (default: 0).
nbds_max
Number of block devices that should be initialized (default: 16).
The nbd kernel module need only be installed on the client
system, as the nbd-server is completely in userspace. In fact,
the nbd-server has been successfully ported to other operating
systems, including Windows.

87
Documentation/blockdev/zram.txt
View File

@ -98,20 +98,79 @@ size of the disk when not in use so a huge zram is wasteful.
mount /dev/zram1 /tmp
7) Stats:
Per-device statistics are exported as various nodes under
/sys/block/zram<id>/
disksize
num_reads
num_writes
failed_reads
failed_writes
invalid_io
notify_free
zero_pages
orig_data_size
compr_data_size
mem_used_total
mem_used_max
Per-device statistics are exported as various nodes under /sys/block/zram<id>/
A brief description of exported device attritbutes. For more details please
read Documentation/ABI/testing/sysfs-block-zram.
Name access description
---- ------ -----------
disksize RW show and set the device's disk size
initstate RO shows the initialization state of the device
reset WO trigger device reset
num_reads RO the number of reads
failed_reads RO the number of failed reads
num_write RO the number of writes
failed_writes RO the number of failed writes
invalid_io RO the number of non-page-size-aligned I/O requests
max_comp_streams RW the number of possible concurrent compress operations
comp_algorithm RW show and change the compression algorithm
notify_free RO the number of notifications to free pages (either
slot free notifications or REQ_DISCARD requests)
zero_pages RO the number of zero filled pages written to this disk
orig_data_size RO uncompressed size of data stored in this disk
compr_data_size RO compressed size of data stored in this disk
mem_used_total RO the amount of memory allocated for this disk
mem_used_max RW the maximum amount memory zram have consumed to
store compressed data
mem_limit RW the maximum amount of memory ZRAM can use to store
the compressed data
num_migrated RO the number of objects migrated migrated by compaction
WARNING
=======
per-stat sysfs attributes are considered to be deprecated.
The basic strategy is:
-- the existing RW nodes will be downgraded to WO nodes (in linux 4.11)
-- deprecated RO sysfs nodes will eventually be removed (in linux 4.11)
The list of deprecated attributes can be found here:
Documentation/ABI/obsolete/sysfs-block-zram
Basically, every attribute that has its own read accessible sysfs node
(e.g. num_reads) *AND* is accessible via one of the stat files (zram<id>/stat
or zram<id>/io_stat or zram<id>/mm_stat) is considered to be deprecated.
User space is advised to use the following files to read the device statistics.
File /sys/block/zram<id>/stat
Represents block layer statistics. Read Documentation/block/stat.txt for
details.
File /sys/block/zram<id>/io_stat
The stat file represents device's I/O statistics not accounted by block
layer and, thus, not available in zram<id>/stat file. It consists of a
single line of text and contains the following stats separated by
whitespace:
failed_reads
failed_writes
invalid_io
notify_free
File /sys/block/zram<id>/mm_stat
The stat file represents device's mm statistics. It consists of a single
line of text and contains the following stats separated by whitespace:
orig_data_size
compr_data_size
mem_used_total
mem_limit
mem_used_max
zero_pages
num_migrated
8) Deactivate:
swapoff /dev/zram0

8
Documentation/cgroups/memory.txt
View File

@ -275,11 +275,6 @@ When oom event notifier is registered, event will be delivered.
2.7 Kernel Memory Extension (CONFIG_MEMCG_KMEM)
WARNING: Current implementation lacks reclaim support. That means allocation
attempts will fail when close to the limit even if there are plenty of
kmem available for reclaim. That makes this option unusable in real
life so DO NOT SELECT IT unless for development purposes.
With the Kernel memory extension, the Memory Controller is able to limit
the amount of kernel memory used by the system. Kernel memory is fundamentally
different than user memory, since it can't be swapped out, which makes it
@ -345,6 +340,9 @@ set:
In this case, the admin could set up K so that the sum of all groups is
never greater than the total memory, and freely set U at the cost of his
QoS.
WARNING: In the current implementation, memory reclaim will NOT be
triggered for a cgroup when it hits K while staying below U, which makes
this setup impractical.
U != 0, K >= U:
Since kmem charges will also be fed to the user counter and reclaim will be

21
Documentation/cma/debugfs.txt 100644
View File

@ -0,0 +1,21 @@
The CMA debugfs interface is useful to retrieve basic information out of the
different CMA areas and to test allocation/release in each of the areas.
Each CMA zone represents a directory under <debugfs>/cma/, indexed by the
kernel's CMA index. So the first CMA zone would be:
<debugfs>/cma/cma-0
The structure of the files created under that directory is as follows:
- [RO] base_pfn: The base PFN (Page Frame Number) of the zone.
- [RO] count: Amount of memory in the CMA area.
- [RO] order_per_bit: Order of pages represented by one bit.
- [RO] bitmap: The bitmap of page states in the zone.
- [WO] alloc: Allocate N pages from that CMA area. For example:
echo 5 > <debugfs>/cma/cma-2/alloc
would try to allocate 5 pages from the cma-2 area.
- [WO] free: Free N pages from that CMA area, similar to the above.

2
Documentation/cpu-hotplug.txt
View File

@ -108,7 +108,7 @@ Never use anything other than cpumask_t to represent bitmap of CPUs.
for_each_possible_cpu - Iterate over cpu_possible_mask
for_each_online_cpu - Iterate over cpu_online_mask
for_each_present_cpu - Iterate over cpu_present_mask
for_each_cpu_mask(x,mask) - Iterate over some random collection of cpu mask.
for_each_cpu(x,mask) - Iterate over some random collection of cpu mask.
#include <linux/cpu.h>
get_online_cpus() and put_online_cpus():

205
Documentation/crypto/crypto-API-userspace.txt
View File

@ -1,205 +0,0 @@
Introduction
============
The concepts of the kernel crypto API visible to kernel space is fully
applicable to the user space interface as well. Therefore, the kernel crypto API
high level discussion for the in-kernel use cases applies here as well.
The major difference, however, is that user space can only act as a consumer
and never as a provider of a transformation or cipher algorithm.
The following covers the user space interface exported by the kernel crypto
API. A working example of this description is libkcapi that can be obtained from
[1]. That library can be used by user space applications that require
cryptographic services from the kernel.
Some details of the in-kernel kernel crypto API aspects do not
apply to user space, however. This includes the difference between synchronous
and asynchronous invocations. The user space API call is fully synchronous.
In addition, only a subset of all cipher types are available as documented
below.
User space API general remarks
==============================
The kernel crypto API is accessible from user space. Currently, the following
ciphers are accessible:
* Message digest including keyed message digest (HMAC, CMAC)
* Symmetric ciphers
Note, AEAD ciphers are currently not supported via the symmetric cipher
interface.
The interface is provided via Netlink using the type AF_ALG. In addition, the
setsockopt option type is SOL_ALG. In case the user space header files do not
export these flags yet, use the following macros:
#ifndef AF_ALG
#define AF_ALG 38
#endif
#ifndef SOL_ALG
#define SOL_ALG 279
#endif
A cipher is accessed with the same name as done for the in-kernel API calls.
This includes the generic vs. unique naming schema for ciphers as well as the
enforcement of priorities for generic names.
To interact with the kernel crypto API, a Netlink socket must be created by
the user space application. User space invokes the cipher operation with the
send/write system call family. The result of the cipher operation is obtained
with the read/recv system call family.
The following API calls assume that the Netlink socket descriptor is already
opened by the user space application and discusses only the kernel crypto API
specific invocations.
To initialize a Netlink interface, the following sequence has to be performed
by the consumer:
1. Create a socket of type AF_ALG with the struct sockaddr_alg parameter
specified below for the different cipher types.
2. Invoke bind with the socket descriptor
3. Invoke accept with the socket descriptor. The accept system call
returns a new file descriptor that is to be used to interact with
the particular cipher instance. When invoking send/write or recv/read
system calls to send data to the kernel or obtain data from the
kernel, the file descriptor returned by accept must be used.
In-place cipher operation
=========================
Just like the in-kernel operation of the kernel crypto API, the user space
interface allows the cipher operation in-place. That means that the input buffer
used for the send/write system call and the output buffer used by the read/recv
system call may be one and the same. This is of particular interest for
symmetric cipher operations where a copying of the output data to its final
destination can be avoided.
If a consumer on the other hand wants to maintain the plaintext and the
ciphertext in different memory locations, all a consumer needs to do is to
provide different memory pointers for the encryption and decryption operation.
Message digest API
==================
The message digest type to be used for the cipher operation is selected when
invoking the bind syscall. bind requires the caller to provide a filled
struct sockaddr data structure. This data structure must be filled as follows:
struct sockaddr_alg sa = {
.salg_family = AF_ALG,
.salg_type = "hash", /* this selects the hash logic in the kernel */
.salg_name = "sha1" /* this is the cipher name */
};
The salg_type value "hash" applies to message digests and keyed message digests.
Though, a keyed message digest is referenced by the appropriate salg_name.
Please see below for the setsockopt interface that explains how the key can be
set for a keyed message digest.
Using the send() system call, the application provides the data that should be
processed with the message digest. The send system call allows the following
flags to be specified:
* MSG_MORE: If this flag is set, the send system call acts like a
message digest update function where the final hash is not
yet calculated. If the flag is not set, the send system call
calculates the final message digest immediately.
With the recv() system call, the application can read the message digest from
the kernel crypto API. If the buffer is too small for the message digest, the
flag MSG_TRUNC is set by the kernel.
In order to set a message digest key, the calling application must use the
setsockopt() option of ALG_SET_KEY. If the key is not set the HMAC operation is
performed without the initial HMAC state change caused by the key.
Symmetric cipher API
====================
The operation is very similar to the message digest discussion. During
initialization, the struct sockaddr data structure must be filled as follows:
struct sockaddr_alg sa = {
.salg_family = AF_ALG,
.salg_type = "skcipher", /* this selects the symmetric cipher */
.salg_name = "cbc(aes)" /* this is the cipher name */
};
Before data can be sent to the kernel using the write/send system call family,
the consumer must set the key. The key setting is described with the setsockopt
invocation below.
Using the sendmsg() system call, the application provides the data that should
be processed for encryption or decryption. In addition, the IV is specified
with the data structure provided by the sendmsg() system call.
The sendmsg system call parameter of struct msghdr is embedded into the
struct cmsghdr data structure. See recv(2) and cmsg(3) for more information
on how the cmsghdr data structure is used together with the send/recv system
call family. That cmsghdr data structure holds the following information
specified with a separate header instances:
* specification of the cipher operation type with one of these flags:
ALG_OP_ENCRYPT - encryption of data
ALG_OP_DECRYPT - decryption of data
* specification of the IV information marked with the flag ALG_SET_IV
The send system call family allows the following flag to be specified:
* MSG_MORE: If this flag is set, the send system call acts like a
cipher update function where more input data is expected
with a subsequent invocation of the send system call.
Note: The kernel reports -EINVAL for any unexpected data. The caller must
make sure that all data matches the constraints given in /proc/crypto for the
selected cipher.
With the recv() system call, the application can read the result of the
cipher operation from the kernel crypto API. The output buffer must be at least
as large as to hold all blocks of the encrypted or decrypted data. If the output
data size is smaller, only as many blocks are returned that fit into that
output buffer size.
Setsockopt interface
====================
In addition to the read/recv and send/write system call handling to send and
retrieve data subject to the cipher operation, a consumer also needs to set
the additional information for the cipher operation. This additional information
is set using the setsockopt system call that must be invoked with the file
descriptor of the open cipher (i.e. the file descriptor returned by the
accept system call).
Each setsockopt invocation must use the level SOL_ALG.
The setsockopt interface allows setting the following data using the mentioned
optname:
* ALG_SET_KEY -- Setting the key. Key setting is applicable to:
- the skcipher cipher type (symmetric ciphers)
- the hash cipher type (keyed message digests)
User space API example
======================
Please see [1] for libkcapi which provides an easy-to-use wrapper around the
aforementioned Netlink kernel interface. [1] also contains a test application
that invokes all libkcapi API calls.
[1] http://www.chronox.de/libkcapi.html
Author
======
Stephan Mueller <smueller@chronox.de>

4
Documentation/device-mapper/dm-crypt.txt
View File

@ -5,7 +5,7 @@ Device-Mapper's "crypt" target provides transparent encryption of block devices
using the kernel crypto API.
For a more detailed description of supported parameters see:
http://code.google.com/p/cryptsetup/wiki/DMCrypt
https://gitlab.com/cryptsetup/cryptsetup/wikis/DMCrypt
Parameters: <cipher> <key> <iv_offset> <device path> \
<offset> [<#opt_params> <opt_params>]
@ -80,7 +80,7 @@ Example scripts
===============
LUKS (Linux Unified Key Setup) is now the preferred way to set up disk
encryption with dm-crypt using the 'cryptsetup' utility, see
http://code.google.com/p/cryptsetup/
https://gitlab.com/cryptsetup/cryptsetup
[[
#!/bin/sh

140
Documentation/device-mapper/log-writes.txt 100644
View File

@ -0,0 +1,140 @@
dm-log-writes
=============
This target takes 2 devices, one to pass all IO to normally, and one to log all
of the write operations to. This is intended for file system developers wishing
to verify the integrity of metadata or data as the file system is written to.
There is a log_write_entry written for every WRITE request and the target is
able to take arbitrary data from userspace to insert into the log. The data
that is in the WRITE requests is copied into the log to make the replay happen
exactly as it happened originally.
Log Ordering
============
We log things in order of completion once we are sure the write is no longer in
cache. This means that normal WRITE requests are not actually logged until the
next REQ_FLUSH request. This is to make it easier for userspace to replay the
log in a way that correlates to what is on disk and not what is in cache, to
make it easier to detect improper waiting/flushing.
This works by attaching all WRITE requests to a list once the write completes.
Once we see a REQ_FLUSH request we splice this list onto the request and once
the FLUSH request completes we log all of the WRITEs and then the FLUSH. Only
completed WRITEs, at the time the REQ_FLUSH is issued, are added in order to
simulate the worst case scenario with regard to power failures. Consider the
following example (W means write, C means complete):
W1,W2,W3,C3,C2,Wflush,C1,Cflush
The log would show the following
W3,W2,flush,W1....
Again this is to simulate what is actually on disk, this allows us to detect
cases where a power failure at a particular point in time would create an
inconsistent file system.
Any REQ_FUA requests bypass this flushing mechanism and are logged as soon as
they complete as those requests will obviously bypass the device cache.
Any REQ_DISCARD requests are treated like WRITE requests. Otherwise we would
have all the DISCARD requests, and then the WRITE requests and then the FLUSH
request. Consider the following example:
WRITE block 1, DISCARD block 1, FLUSH
If we logged DISCARD when it completed, the replay would look like this
DISCARD 1, WRITE 1, FLUSH
which isn't quite what happened and wouldn't be caught during the log replay.
Target interface
================
i) Constructor
log-writes <dev_path> <log_dev_path>
dev_path : Device that all of the IO will go to normally.
log_dev_path : Device where the log entries are written to.
ii) Status
<#logged entries> <highest allocated sector>
#logged entries : Number of logged entries
highest allocated sector : Highest allocated sector
iii) Messages
mark <description>
You can use a dmsetup message to set an arbitrary mark in a log.
For example say you want to fsck a file system after every
write, but first you need to replay up to the mkfs to make sure
we're fsck'ing something reasonable, you would do something like
this:
mkfs.btrfs -f /dev/mapper/log
dmsetup message log 0 mark mkfs
<run test>
This would allow you to replay the log up to the mkfs mark and
then replay from that point on doing the fsck check in the
interval that you want.
Every log has a mark at the end labeled "dm-log-writes-end".
Userspace component
===================
There is a userspace tool that will replay the log for you in various ways.
It can be found here: https://github.com/josefbacik/log-writes
Example usage
=============
Say you want to test fsync on your file system. You would do something like
this:
TABLE="0 $(blockdev --getsz /dev/sdb) log-writes /dev/sdb /dev/sdc"
dmsetup create log --table "$TABLE"
mkfs.btrfs -f /dev/mapper/log
dmsetup message log 0 mark mkfs
mount /dev/mapper/log /mnt/btrfs-test
<some test that does fsync at the end>
dmsetup message log 0 mark fsync
md5sum /mnt/btrfs-test/foo
umount /mnt/btrfs-test
dmsetup remove log
replay-log --log /dev/sdc --replay /dev/sdb --end-mark fsync
mount /dev/sdb /mnt/btrfs-test
md5sum /mnt/btrfs-test/foo
<verify md5sum's are correct>
Another option is to do a complicated file system operation and verify the file
system is consistent during the entire operation. You could do this with:
TABLE="0 $(blockdev --getsz /dev/sdb) log-writes /dev/sdb /dev/sdc"
dmsetup create log --table "$TABLE"
mkfs.btrfs -f /dev/mapper/log
dmsetup message log 0 mark mkfs
mount /dev/mapper/log /mnt/btrfs-test
<fsstress to dirty the fs>
btrfs filesystem balance /mnt/btrfs-test
umount /mnt/btrfs-test
dmsetup remove log
replay-log --log /dev/sdc --replay /dev/sdb --end-mark mkfs
btrfsck /dev/sdb
replay-log --log /dev/sdc --replay /dev/sdb --start-mark mkfs \
--fsck "btrfsck /dev/sdb" --check fua
And that will replay the log until it sees a FUA request, run the fsck command
and if the fsck passes it will replay to the next FUA, until it is completed or
the fsck command exists abnormally.

4
Documentation/device-mapper/switch.txt
View File

@ -47,8 +47,8 @@ consume far too much memory.
Using this device-mapper switch target we can now build a two-layer
device hierarchy:
Upper Tier – Determine which array member the I/O should be sent to.
Lower Tier – Load balance amongst paths to a particular member.
Upper Tier - Determine which array member the I/O should be sent to.
Lower Tier - Load balance amongst paths to a particular member.
The lower tier consists of a single dm multipath device for each member.
Each of these multipath devices contains the set of paths directly to

3
Documentation/device-mapper/thin-provisioning.txt
View File

@ -380,9 +380,6 @@ then you'll have no access to blocks mapped beyond the end. If you
load a target that is bigger than before, then extra blocks will be
provisioned as and when needed.
If you wish to reduce the size of your thin device and potentially
regain some space then send the 'trim' message to the pool.
ii) Status
<nr mapped sectors> <highest mapped sector>

21
Documentation/device-mapper/verity.txt
View File

@ -11,6 +11,7 @@ Construction Parameters
<data_block_size> <hash_block_size>
<num_data_blocks> <hash_start_block>
<algorithm> <digest> <salt>
[<#opt_params> <opt_params>]
<version>
This is the type of the on-disk hash format.
@ -62,6 +63,22 @@ Construction Parameters
<salt>
The hexadecimal encoding of the salt value.
<#opt_params>
Number of optional parameters. If there are no optional parameters,
the optional paramaters section can be skipped or #opt_params can be zero.
Otherwise #opt_params is the number of following arguments.
Example of optional parameters section:
1 ignore_corruption
ignore_corruption
Log corrupted blocks, but allow read operations to proceed normally.
restart_on_corruption
Restart the system when a corrupted block is discovered. This option is
not compatible with ignore_corruption and requires user space support to
avoid restart loops.
Theory of operation
===================
@ -125,7 +142,7 @@ block boundary) are the hash blocks which are stored a depth at a time
The full specification of kernel parameters and on-disk metadata format
is available at the cryptsetup project's wiki page
http://code.google.com/p/cryptsetup/wiki/DMVerity
https://gitlab.com/cryptsetup/cryptsetup/wikis/DMVerity
Status
======
@ -142,7 +159,7 @@ Set up a device:
A command line tool veritysetup is available to compute or verify
the hash tree or activate the kernel device. This is available from
the cryptsetup upstream repository http://code.google.com/p/cryptsetup/
the cryptsetup upstream repository https://gitlab.com/cryptsetup/cryptsetup/
(as a libcryptsetup extension).
Create hash on the device:

20
Documentation/devicetree/bindings/arc/pct.txt 100644
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@ -0,0 +1,20 @@
* ARC Performance Counters
The ARC700 can be configured with a pipeline performance monitor for counting
CPU and cache events like cache misses and hits. Like conventional PCT there
are 100+ hardware conditions dynamically mapped to upto 32 counters
Note that:
* The ARC 700 PCT does not support interrupts; although HW events may be
counted, the HW events themselves cannot serve as a trigger for a sample.
Required properties:
- compatible : should contain
"snps,arc700-pct"
Example:
pmu {
compatible = "snps,arc700-pct";
};

24
Documentation/devicetree/bindings/arc/pmu.txt
View File

@ -1,24 +0,0 @@
* ARC Performance Monitor Unit
The ARC 700 can be configured with a pipeline performance monitor for counting
CPU and cache events like cache misses and hits.
Note that:
* ARC 700 refers to a family of ARC processor cores;
- There is only one type of PMU available for the whole family;
- The PMU may support different sets of events; supported events are probed
at boot time, as required by the reference manual.
* The ARC 700 PMU does not support interrupts; although HW events may be
counted, the HW events themselves cannot serve as a trigger for a sample.
Required properties:
- compatible : should contain
"snps,arc700-pmu"
Example:
pmu {
compatible = "snps,arc700-pmu";
};

88
Documentation/devicetree/bindings/arm/al,alpine.txt 100644
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@ -0,0 +1,88 @@
Annapurna Labs Alpine Platform Device Tree Bindings
---------------------------------------------------------------
Boards in the Alpine family shall have the following properties:
* Required root node properties:
compatible: must contain "al,alpine"
* Example:
/ {
model = "Annapurna Labs Alpine Dev Board";
compatible = "al,alpine";
...
}
* CPU node:
The Alpine platform includes cortex-a15 cores.
enable-method: must be "al,alpine-smp" to allow smp [1]
Example:
cpus {
#address-cells = <1>;
#size-cells = <0>;
enable-method = "al,alpine-smp";
cpu@0 {
compatible = "arm,cortex-a15";
device_type = "cpu";
reg = <0>;
};
cpu@1 {
compatible = "arm,cortex-a15";
device_type = "cpu";
reg = <1>;
};
cpu@2 {
compatible = "arm,cortex-a15";
device_type = "cpu";
reg = <2>;
};
cpu@3 {
compatible = "arm,cortex-a15";
device_type = "cpu";
reg = <3>;
};
};
* Alpine CPU resume registers
The CPU resume register are used to define required resume address after
reset.
Properties:
- compatible : Should contain "al,alpine-cpu-resume".
- reg : Offset and length of the register set for the device
Example:
cpu_resume {
compatible = "al,alpine-cpu-resume";
reg = <0xfbff5ed0 0x30>;
};
* Alpine System-Fabric Service Registers
The System-Fabric Service Registers allow various operation on CPU and
system fabric, like powering CPUs off.
Properties:
- compatible : Should contain "al,alpine-sysfabric-service" and "syscon".
- reg : Offset and length of the register set for the device
Example:
nb_service {
compatible = "al,alpine-sysfabric-service", "syscon";
reg = <0xfb070000 0x10000>;
};
[1] arm/cpu-enable-method/al,alpine-smp

14
Documentation/devicetree/bindings/arm/altera.txt 100644
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@ -0,0 +1,14 @@
Altera's SoCFPGA platform device tree bindings
---------------------------------------------
Boards with Cyclone 5 SoC:
Required root node properties:
compatible = "altr,socfpga-cyclone5", "altr,socfpga";
Boards with Arria 5 SoC:
Required root node properties:
compatible = "altr,socfpga-arria5", "altr,socfpga";
Boards with Arria 10 SoC:
Required root node properties:
compatible = "altr,socfpga-arria10", "altr,socfpga";

4
Documentation/devicetree/bindings/arm/amlogic.txt
View File

@ -8,3 +8,7 @@ Boards with the Amlogic Meson6 SoC shall have the following properties:
Boards with the Amlogic Meson8 SoC shall have the following properties:
Required root node property:
compatible: "amlogic,meson8";
Board compatible values:
- "geniatech,atv1200"
- "minix,neo-x8"

8
Documentation/devicetree/bindings/arm/arch_timer.txt
View File

@ -17,7 +17,10 @@ to deliver its interrupts via SPIs.
- interrupts : Interrupt list for secure, non-secure, virtual and
hypervisor timers, in that order.
- clock-frequency : The frequency of the main counter, in Hz. Optional.
- clock-frequency : The frequency of the main counter, in Hz. Should be present
only where necessary to work around broken firmware which does not configure
CNTFRQ on all CPUs to a uniform correct value. Use of this property is
strongly discouraged; fix your firmware unless absolutely impossible.
- always-on : a boolean property. If present, the timer is powered through an
always-on power domain, therefore it never loses context.
@ -46,7 +49,8 @@ Example:
- compatible : Should at least contain "arm,armv7-timer-mem".
- clock-frequency : The frequency of the main counter, in Hz. Optional.
- clock-frequency : The frequency of the main counter, in Hz. Should be present
only when firmware has not configured the MMIO CNTFRQ registers.
- reg : The control frame base address.

20
Documentation/devicetree/bindings/arm/armada-39x.txt 100644
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@ -0,0 +1,20 @@
Marvell Armada 39x Platforms Device Tree Bindings
-------------------------------------------------
Boards with a SoC of the Marvell Armada 39x family shall have the
following property:
Required root node property:
- compatible: must contain "marvell,armada390"
In addition, boards using the Marvell Armada 398 SoC shall have the
following property before the previous one:
Required root node property:
compatible: must contain "marvell,armada398"
Example:
compatible = "marvell,a398-db", "marvell,armada398", "marvell,armada390";

4
Documentation/devicetree/bindings/arm/atmel-at91.txt
View File

@ -46,10 +46,12 @@ PIT Timer required properties:
shared across all System Controller members.
System Timer (ST) required properties:
- compatible: Should be "atmel,at91rm9200-st"
- compatible: Should be "atmel,at91rm9200-st", "syscon", "simple-mfd"
- reg: Should contain registers location and length
- interrupts: Should contain interrupt for the ST which is the IRQ line
shared across all System Controller members.
Its subnodes can be:
- watchdog: compatible should be "atmel,at91rm9200-wdt"
TC/TCLIB Timer required properties:
- compatible: Should be "atmel,<chip>-tcb".

0
Documentation/devicetree/bindings/arm/bcm/brcm,bcm11351-cpu-method → Documentation/devicetree/bindings/arm/bcm/brcm,bcm11351-cpu-method.txt
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0
Documentation/devicetree/bindings/arm/bcm/bcm11351.txt → Documentation/devicetree/bindings/arm/bcm/brcm,bcm11351.txt
View File

0
Documentation/devicetree/bindings/arm/bcm/bcm21664.txt → Documentation/devicetree/bindings/arm/bcm/brcm,bcm21664.txt
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0
Documentation/devicetree/bindings/arm/bcm2835.txt → Documentation/devicetree/bindings/arm/bcm/brcm,bcm2835.txt
View File

0
Documentation/devicetree/bindings/arm/bcm4708.txt → Documentation/devicetree/bindings/arm/bcm/brcm,bcm4708.txt
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0
Documentation/devicetree/bindings/arm/bcm/bcm63138.txt → Documentation/devicetree/bindings/arm/bcm/brcm,bcm63138.txt
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0
Documentation/devicetree/bindings/arm/brcm-brcmstb.txt → Documentation/devicetree/bindings/arm/bcm/brcm,brcmstb.txt
View File

0
Documentation/devicetree/bindings/arm/bcm/cygnus.txt → Documentation/devicetree/bindings/arm/bcm/brcm,cygnus.txt
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7
Documentation/devicetree/bindings/arm/cci.txt
View File

@ -94,8 +94,11 @@ specific to ARM.
- compatible
Usage: required
Value type: <string>
Definition: must be "arm,cci-400-pmu"
Definition: Must contain one of:
"arm,cci-400-pmu,r0"
"arm,cci-400-pmu,r1"
"arm,cci-400-pmu" - DEPRECATED, permitted only where OS has
secure acces to CCI registers
- reg:
Usage: required
Value type: Integer cells. A register entry, expressed

1
Documentation/devicetree/bindings/arm/coresight.txt
View File

@ -61,7 +61,6 @@ Example:
compatible = "arm,coresight-etb10", "arm,primecell";
reg = <0 0x20010000 0 0x1000>;
coresight-default-sink;
clocks = <&oscclk6a>;
clock-names = "apb_pclk";
port {

52
Documentation/devicetree/bindings/arm/cpu-enable-method/al,alpine-smp 100644
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@ -0,0 +1,52 @@
========================================================
Secondary CPU enable-method "al,alpine-smp" binding
========================================================
This document describes the "al,alpine-smp" method for
enabling secondary CPUs. To apply to all CPUs, a single
"al,alpine-smp" enable method should be defined in the
"cpus" node.
Enable method name: "al,alpine-smp"
Compatible machines: "al,alpine"
Compatible CPUs: "arm,cortex-a15"
Related properties: (none)
Note:
This enable method requires valid nodes compatible with
"al,alpine-cpu-resume" and "al,alpine-nb-service"[1].
Example:
cpus {
#address-cells = <1>;
#size-cells = <0>;
enable-method = "al,alpine-smp";
cpu@0 {
compatible = "arm,cortex-a15";
device_type = "cpu";
reg = <0>;
};
cpu@1 {
compatible = "arm,cortex-a15";
device_type = "cpu";
reg = <1>;
};
cpu@2 {
compatible = "arm,cortex-a15";
device_type = "cpu";
reg = <2>;
};
cpu@3 {
compatible = "arm,cortex-a15";
device_type = "cpu";
reg = <3>;
};
};
--
[1] arm/al,alpine.txt

1
Documentation/devicetree/bindings/arm/cpus.txt
View File

@ -192,6 +192,7 @@ nodes to be present and contain the properties described below.
"brcm,brahma-b15"
"marvell,armada-375-smp"
"marvell,armada-380-smp"
"marvell,armada-390-smp"
"marvell,armada-xp-smp"
"qcom,gcc-msm8660"
"qcom,kpss-acc-v1"

3
Documentation/devicetree/bindings/arm/exynos/power_domain.txt
View File

@ -22,6 +22,9 @@ Optional Properties:
- pclkN, clkN: Pairs of parent of input clock and input clock to the
devices in this power domain. Maximum of 4 pairs (N = 0 to 3)
are supported currently.
- asbN: Clocks required by asynchronous bridges (ASB) present in
the power domain. These clock should be enabled during power
domain on/off operations.
- power-domains: phandle pointing to the parent power domain, for more details
see Documentation/devicetree/bindings/power/power_domain.txt

5
Documentation/devicetree/bindings/arm/geniatech.txt
View File

@ -1,5 +0,0 @@
Geniatech platforms device tree bindings
-------------------------------------------
Geniatech ATV1200
- compatible = "geniatech,atv1200"

2
Documentation/devicetree/bindings/arm/gic.txt
View File

@ -18,6 +18,8 @@ Main node required properties:
"arm,arm11mp-gic"
"brcm,brahma-b15-gic"
"arm,arm1176jzf-devchip-gic"
"qcom,msm-8660-qgic"
"qcom,msm-qgic2"
- interrupt-controller : Identifies the node as an interrupt controller
- #interrupt-cells : Specifies the number of cells needed to encode an
interrupt source. The type shall be a <u32> and the value shall be 3.

1
Documentation/devicetree/bindings/arm/marvell,kirkwood.txt
View File

@ -42,6 +42,7 @@ board. Currently known boards are:
"lacie,cloudbox"
"lacie,inetspace_v2"
"lacie,laplug"
"lacie,nas2big"
"lacie,netspace_lite_v2"
"lacie,netspace_max_v2"
"lacie,netspace_mini_v2"

84
Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt 100644
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@ -0,0 +1,84 @@
QCOM Idle States for cpuidle driver
ARM provides idle-state node to define the cpuidle states, as defined in [1].
cpuidle-qcom is the cpuidle driver for Qualcomm SoCs and uses these idle
states. Idle states have different enter/exit latency and residency values.
The idle states supported by the QCOM SoC are defined as -
* Standby
* Retention
* Standalone Power Collapse (Standalone PC or SPC)
* Power Collapse (PC)
Standby: Standby does a little more in addition to architectural clock gating.
When the WFI instruction is executed the ARM core would gate its internal
clocks. In addition to gating the clocks, QCOM cpus use this instruction as a
trigger to execute the SPM state machine. The SPM state machine waits for the
interrupt to trigger the core back in to active. This triggers the cache
hierarchy to enter standby states, when all cpus are idle. An interrupt brings
the SPM state machine out of its wait, the next step is to ensure that the
cache hierarchy is also out of standby, and then the cpu is allowed to resume
execution. This state is defined as a generic ARM WFI state by the ARM cpuidle
driver and is not defined in the DT. The SPM state machine should be
configured to execute this state by default and after executing every other
state below.
Retention: Retention is a low power state where the core is clock gated and
the memory and the registers associated with the core are retained. The
voltage may be reduced to the minimum value needed to keep the processor
registers active. The SPM should be configured to execute the retention
sequence and would wait for interrupt, before restoring the cpu to execution
state. Retention may have a slightly higher latency than Standby.
Standalone PC: A cpu can power down and warmboot if there is a sufficient time
between the time it enters idle and the next known wake up. SPC mode is used
to indicate a core entering a power down state without consulting any other
cpu or the system resources. This helps save power only on that core. The SPM
sequence for this idle state is programmed to power down the supply to the
core, wait for the interrupt, restore power to the core, and ensure the
system state including cache hierarchy is ready before allowing core to
resume. Applying power and resetting the core causes the core to warmboot
back into Elevation Level (EL) which trampolines the control back to the
kernel. Entering a power down state for the cpu, needs to be done by trapping
into a EL. Failing to do so, would result in a crash enforced by the warm boot
code in the EL for the SoC. On SoCs with write-back L1 cache, the cache has to
be flushed in s/w, before powering down the core.
Power Collapse: This state is similar to the SPC mode, but distinguishes
itself in that the cpu acknowledges and permits the SoC to enter deeper sleep
modes. In a hierarchical power domain SoC, this means L2 and other caches can
be flushed, system bus, clocks - lowered, and SoC main XO clock gated and
voltages reduced, provided all cpus enter this state. Since the span of low
power modes possible at this state is vast, the exit latency and the residency
of this low power mode would be considered high even though at a cpu level,
this essentially is cpu power down. The SPM in this state also may handshake
with the Resource power manager (RPM) processor in the SoC to indicate a
complete application processor subsystem shut down.
The idle-state for QCOM SoCs are distinguished by the compatible property of
the idle-states device node.
The devicetree representation of the idle state should be -
Required properties:
- compatible: Must be one of -
"qcom,idle-state-ret",
"qcom,idle-state-spc",
"qcom,idle-state-pc",
and "arm,idle-state".
Other required and optional properties are specified in [1].
Example:
idle-states {
CPU_SPC: spc {
compatible = "qcom,idle-state-spc", "arm,idle-state";
entry-latency-us = <150>;
exit-latency-us = <200>;
min-residency-us = <2000>;
};
};
[1]. Documentation/devicetree/bindings/arm/idle-states.txt

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