The tty core no longer provides nor uses ASYNC_CLOSING; remove from
tty_port_close_start() and tty_port_close_end() as well as tty drivers
which open-code these state changes. Unfortunately, even though the
bit is masked from userspace, its inclusion in a uapi header precludes
removing the macro.
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: linux-cris-kernel@axis.com
Cc: Samuel Ortiz <samuel@sortiz.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When throttling, time is of the essence; try RTS signalling before
soft flow control, which will take longer.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
void * promotes to any pointer type; remove type cast.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If aborting uart_open() unsuccessfully, retval is non-zero, so the
existing fall-through exit is equivalent.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The uart port may have already been removed by uart_remove_one_port();
use equivalent tty->index (which is always valid in these contexts)
instead.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
do_uart_get_info() has a single caller: uart_get_info().
Manually inline do_uart_get_info().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Expressions of the form "tty->termios.c_*flag & FLAG"
are more clearly expressed with the termios flags macros,
I_FLAG(), C_FLAG(), O_FLAG(), and L_FLAG().
Convert treewide.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, 8-bit (MMIO) and 32-bit (MMIO32) register interfaces are
supported for the 8250 console, but the 16-bit (MMIO16) is not.
The 8250 UART device on my board is connected to a 16-bit bus and
my main motivation is to use earlycon with it.
(Refer to arch/arm/boot/dts/uniphier-support-card.dtsi)
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
With the removal of tty_wait_until_sent_from_close(), tty drivers
no longer wait during open for parallel closes to complete (instead,
the tty core waits before calling the driver open() method). Thus,
the close_wait waitqueue is no longer used for waiting.
Remove struct tty_port::close_wait.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There are three natural ways in which devices may be wired to the system:
little endian (device receives correctly ordered bits of a word written
by little-endian CPU to its register, but big-endian CPU needs to swap
bytes of a word before writing it), big endian (same, but with big-endian
CPU in more favourable position) and native endian (CPU of either
endianness may do word-sized I/O without need for byteswapping).
Adding an option for native endianness allows using single kernel command
line for boards with native-endian serial ports on bi-endian
architectures. This goes in parallel with 'native-endian' DTS attribute.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial core does not use tty_port_open() or tty_port_close(); serial
core defines and extends it's own tty open() and close() methods
(uart_open() and uart_close(), respectively).
Remove the tty_port activate() and shutdown() initializations, and
the uart_port_activate() function, which is never called.
NB: uart_port_shutdown() is used by uart_close() => uart_shutdown()
call chain (but not via the tty_port methods).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
uart_close() runs in non-atomic context only; use
spin_lock/unlock_irq instead of saving the interrupt state (which
== on).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
While closing, new rx data may be received after the input buffers
have been flushed but before stop_rx() halts receiving [1]. The
new data might not be processed by flush_to_ldisc() until after
uart_shutdown() and normal input processing is re-enabled (ie.,
tty->closing = 0). The race is outlined below:
CPU 0 | CPU 1
|
uart_close() |
tty_port_close_start() |
tty->closing = 1 |
tty_ldisc_flush() |
| => IRQ
| while (LSR & data ready)
| uart_insert_char()
| tty_flip_buffer_push()
| <= EOI
stop_rx() | .
uart_shutdown() | .
free xmit.buf | .
tty_port_tty_set(NULL) | .
tty->closing = 0 | .
| flush_to_ldisc()
| n_tty_receive_buf_common()
| __receive_buf()
| ...
| commit_echoes()
| uart_flush_chars()
| __uart_start()
| ** OOPS on port.tty deref **
tty_ldisc_flush() |
Input processing must be prevented from echoing (tty->closing = 1)
until _after_ the input buffers have been flushed again at the end
of uart_close().
[1] In fact, some input may actually be buffered _after_ stop_rx()
since the rx interrupt may have already triggered but not yet been
handled when stop_rx() disables rx interrupts.
Fixes: 2e75891083 ("serial: core: Flush ldisc after dropping port
mutex in uart_close()")
Reported-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Align with coding guidelines:
Replaced a chain of "else if" by a switch case.
Signed-off-by: Joakim Nordell <joakim.nordell@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Support command line parameters of the form:
earlycon=<name>,io|mmio|mmio32|mmio32be,<addr>,<options>
This commit seem to be needed even after commit:
serial: 8250: Add support for big-endian MMIO accesses
c627f2ceb6
Signed-off-by: Noam Camus <noamc@ezchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_name no longer uses the buf parameter, so remove it along with all
the 64 byte stack buffers that used to be passed in.
Mostly generated by the coccinelle script
@depends on patch@
identifier buf;
constant C;
expression tty;
@@
- char buf[C];
<+...
- tty_name(tty, buf)
+ tty_name(tty)
...+>
allmodconfig compiles, so I'm fairly confident the stack buffers
weren't used for other purposes as well.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
'/**' is required to start a kernel-doc comment block.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
UART drivers that share ttyS namespace cannot trivially compute the
ttyS index from the port->line value since the minor_start may be
offset from minor 64. Further, to do so requires a pointer to the
uart driver since there is no back pointer from uart_port to
uart_driver.
Rather than have UART drivers computing the minor value by themselves,
encapsulate within the serial core at port registration time.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Prepare to support console-defined matching; refactor the command
line parameter string processing from parse_options() into a
new core function, uart_parse_earlycon(), which decodes command line
parameters of the form:
earlycon=<name>,io|mmio|mmio32,<addr>,<options>
console=<name>,io|mmio|mmio32,<addr>,<options>
earlycon=<name>,0x<addr>,<options>
console=<name>,0x<addr>,<options>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use helper functions to access current->state.
Direct assignments are prone to races and therefore buggy.
Thanks to Peter Zijlstra for the exact definition of the problem.
Suggested-By: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
hw-assisted flow control support was added to the serial core
in v3.8 with commits,
dba05832cb ("SERIAL: core: add hardware assisted h/w flow control support")
2cbacafd7a ("SERIAL: core: add hardware assisted s/w flow control support")
9aba8d5b01 ("SERIAL: core: add throttle/unthrottle callbacks for hardware
assisted flow control")
Since then, additional requirements for serial core support have arisen.
Specifically,
1. Separate tx and rx flow control settings for UARTs which only support
tx flow control (ie., autoCTS).
2. Disable sw-assisted CTS flow control in autoCTS mode
3. Support for RTS flow control by serial core and userspace in autoRTS mode
Distinguish mode from capability; introduce UPSTAT_AUTORTS, UPSTAT_AUTOCTS
and UPSTAT_AUTOXOFF which, when set by the uart driver, enable serial core
support for hw-assisted rx, hw-assisted tx and hw-assisted in-band/IXOFF
rx flow control, respectively. [Note: hw-assisted in-band/IXON tx flow
control does not require serial core support/intervention and can be
enabled by the uart driver when required.]
These modes must be set/reset in the driver's set_termios() method, based
on termios settings, and thus can be safely queried in any context in which
one of the port lock, port mutex or termios rwsem are held. Set these modes
in the 2 in-tree drivers, omap-serial and 8250_omap, which currently
use UPF_HARD_FLOW/UPF_SOFT_FLOW support.
Retain UPF_HARD_FLOW and UPF_SOFT_FLOW as capabilities; re-define
UPF_HARD_FLOW as both UPF_AUTO_RTS and UPF_AUTO_CTS to allow for distinct
and separate rx and tx flow control capabilities.
Disable sw-assisted CTS flow control when UPSTAT_AUTOCTS is enabled.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When the uart port being suspended is a console and consoles are
not suspending (kernel command line contains no_console_suspend),
then no action is performed for that port, and the function can
return early.
If the function has not returned early, then one of the conditions
is not true, so the expression
(console_suspend_enabled || !uart_console(uport))
must be true and can be eliminated.
Similarly, the expression
(console_suspend_enabled && uart_console(uport))
simplifies to just uart_console(uport).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is a partial revert of 2f2dafe (serial: serial_core.c: printk
replacement) which gets us booting again. The real problem seems to be
the _emit path in early boot. However, until we can root cause it, we
need at least to get boot working.
Fixes: 2f2dafe77d
Cc: stable@vger.kernel.org
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since most drivers interpret UPIO_MEM32 to mean "little-endian" and use
readl/writel to access the registers, add a parallel UPIO_MEM32BE to
request the use of big-endian MMIO accessors (ioread32be/iowrite32be).
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Introduce an homogeneous lock system between setting and using the rs485
data of the uart_port.
This patch should not be split into multiple ones in order to avoid
leaving the tree in an unstable state.
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Suggested-by: Alan Cox <alan@linux.intel.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Once there is no more handlers for TIOC[GS]RS485 there is no need to
call the driver specific ioctl when the generic implementation is
missing.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The following drivers: 8250_core, atmel_serial, max310x, mcf, omap-serial
and sci16is7xx implement code to handle RS485 ioctls.
In order to avoid code duplication, we implement a simple ioctl handler
on the serial_core layer.
This handler can be used by all the other drivers instead of duplicating
code.
Until this is the only RS485 ioctl handler, it will try first the
rs485_config callback and if it is not present it will call the driver
specific ioctl.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
UART drivers which enable modem status interrupts when switching
to N_PPS line discipline need to determine if modem status
interrupts should be disabled when switching from N_PPS.
Specifically, the set_ldisc() notification needs to evaluate
UART_ENABLE_MS() which requires termios->c_cflag.
Convert in-tree UART drivers to new interface.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Three UART drivers (8250, atmel & amba-pl010) enable modem status
interrupts if the line discipline is changed to N_PPS. However,
the uart port flags may only be safely modified while holding the
port mutex.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We need the fixes in drivers/tty/tty_io.c that were done in there for
future patches in this branch.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
A port count mismatch occurs if mutex_lock_interruptible()
exits uart_open() and the port has already been opened. This may
prematurely close a port on an open tty. Since uart_close() is _always_
called if uart_open() fails, the port count must be corrected if errors
occur.
Always increment the port count in uart_open(), regardless of errors;
always decrement the port count in uart_close(). Note that
tty_port_close_start() decrements the port count when uart_open()
was successful.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
uart_start() only claims the port->lock to call __uart_start(),
which does the actual processing. Eliminate the extra acquire/release
in uart_write(); call __uart_start() directly with port->lock already
held.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The key function of uart_add_one_port() is to cross-reference the
UART driver's port structure with the serial core's state table;
keep the assignments together and document this crucial association.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_port_init() initializes close_delay and closing_wait to these
same values; remove.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The wrapped line looks wrong and out-of-place; leave it as
>80 char line.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The low-level uart driver may modify termios settings to override
settings that are not compatible with the uart, such as CRTSCTS.
Thus, callers of the low-level uart driver's set_termios() method must
hold termios_rwsem write lock to prevent concurrent access to termios,
in case such override occurs.
The termios_rwsem lock requirement does not extend to console setup
(ie., uart_set_options), as console setup cannot race with tty
operations. Nor does this lock requirement extend to functions which
cannot be concurrent with tty ioctls (ie., uart_port_startup() and
uart_resume_port()).
Further, always claim the port mutex to protect hardware
re-reprogramming in the set_termios() uart driver method. Note this
is unnecessary for console initialization in uart_set_options()
which cannot be concurrent with other uart operations.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The tty buffers (and any line discipline buffers) must be flushed after
the UART hardware has shutdown; otherwise, a racing open on the same
tty may receive data from the previous session, which is a security
hazard. However, holding the port mutex while flushing the line
discipline buffers creates a lock inversion if the set_termios()
handler takes the port mutex (as it does in the followup patch,
'serial: Fix locking for uart driver set_termios method'.
Flush the ldisc buffers after dropping the port mutex; the tty lock
is still held which prevents a concurrent open() from advancing while
flushing. Since no new rx data is possible after uart_shutdown() until
a new open reinitializes the port, the later flush has no impact on
what data is being discarded.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In the context of the final tty & port close, flushing the tx
ring buffer after the hardware has already been shutdown and
the ring buffer freed is neither required nor desirable.
uart_flush_buffer() performs 3 operations:
1. Resets tx ring buffer indices, but the tx ring buffer has
already been freed and the indices are reset if the port is
re-opened.
2. Calls uart driver's flush_buffer() method
5 in-tree uart drivers define flush_buffer() methods:
amba-pl011, atmel-serial, imx, serial-tegra, timbuart
These have been refactored into the shutdown() method, if
required.
3. Kicks the ldisc for more writing, but this is undesirable.
The file handle is being released; any waiting writer will
will be kicked out by tty_release() with a warning. Further,
the N_TTY ldisc may generate SIGIO for a file handle which
is no longer valid.
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The struct uart_port.flags field is type upf_t, as are the matching
bit definitions. Change local mask variable to type upf_t.
Fixes sparse warnings:
drivers/tty/serial/serial_core.c:620:22: warning: invalid assignment: |=
drivers/tty/serial/serial_core.c:620:22: left side has type unsigned int
drivers/tty/serial/serial_core.c:620:22: right side has type restricted upf_t
drivers/tty/serial/serial_core.c:622:22: warning: invalid assignment: |=
drivers/tty/serial/serial_core.c:622:22: left side has type unsigned int
drivers/tty/serial/serial_core.c:622:22: right side has type restricted upf_t
drivers/tty/serial/serial_core.c:624:17: warning: restricted upf_t degrades to integer
drivers/tty/serial/serial_core.c:626:22: warning: invalid assignment: &=
drivers/tty/serial/serial_core.c:626:22: left side has type unsigned int
drivers/tty/serial/serial_core.c:626:22: right side has type restricted upf_t
drivers/tty/serial/serial_core.c:629:20: warning: restricted upf_t degrades to integer
drivers/tty/serial/serial_core.c:632:20: warning: restricted upf_t degrades to integer
drivers/tty/serial/serial_core.c:643:22: warning: invalid assignment: |=
drivers/tty/serial/serial_core.c:643:22: left side has type unsigned int
drivers/tty/serial/serial_core.c:643:22: right side has type restricted upf_t
drivers/tty/serial/serial_core.c:645:22: warning: invalid assignment: |=
drivers/tty/serial/serial_core.c:645:22: left side has type unsigned int
drivers/tty/serial/serial_core.c:645:22: right side has type restricted upf_t
drivers/tty/serial/serial_core.c:647:17: warning: restricted upf_t degrades to integer
drivers/tty/serial/serial_core.c:649:22: warning: invalid assignment: &=
drivers/tty/serial/serial_core.c:649:22: left side has type unsigned int
drivers/tty/serial/serial_core.c:649:22: right side has type restricted upf_t
drivers/tty/serial/serial_core.c:652:20: warning: restricted upf_t degrades to integer
drivers/tty/serial/serial_core.c:655:20: warning: restricted upf_t degrades to integer
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 299245a145,
serial: core: Privatize modem status enable flags, introduced
the upstat_t type and matching bit definitions. The purpose is to
produce sparse warnings if the wrong bit definitions are used
(by warning of implicit integer conversions).
Fix implicit conversion to integer return type from uart_cts_enabled()
and uart_dcd_enabled().
Fixes the following sparse warnings:
drivers/tty/serial/serial_core.c:63:30: warning: incorrect type in return expression (different base types)
drivers/tty/serial/serial_core.c:63:30: expected int
drivers/tty/serial/serial_core.c:63:30: got restricted upstat_t
include/linux/serial_core.h:364:30: warning: incorrect type in return expression (different base types)
include/linux/serial_core.h:364:30: expected bool
include/linux/serial_core.h:364:30: got restricted upstat_t
include/linux/serial_core.h:364:30: warning: incorrect type in return expression (different base types)
include/linux/serial_core.h:364:30: expected bool
include/linux/serial_core.h:364:30: got restricted upstat_t
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
uart_get_baud_rate() will return baud == 0 if the max rate is set
to the "magic" 38400 rate and the SPD_* flags are also specified.
On the first iteration, if the current baud rate is higher than the
max, the baud rate is clamped at the max (which in the degenerate
case is 38400). On the second iteration, the now-"magic" 38400 baud
rate selects the possibly higher alternate baud rate indicated by
the SPD_* flag. Since only two loop iterations are performed, the
loop is exited, a kernel WARNING is generated and a baud rate of
0 is returned.
Reproducible with:
setserial /dev/ttyS0 spd_hi base_baud 38400
Only perform the "magic" 38400 -> SPD_* baud transform on the first
loop iteration, which prevents the degenerate case from recognizing
the clamped baud rate as the "magic" 38400 value.
Reported-by: Robert Święcki <robert@swiecki.net>
Cc: <stable@vger.kernel.org> # all
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit a86713b153.
Kevin Hilman writes:
Multiple boot failures on ARM[1] were bisected down to this
patch.
How was this patch tested, and on which platforms?
Also, the changelog states that this should be done only for
UART_CAP_SLEEP, but the patch does it for every UART.
Greg, I suggest this patch be dropped from tty-next until it has
been better described and tested.
[1] http://lists.linaro.org/pipermail/kernel-build-reports/2014-October/005550.html
Reported-by: Kevin Hilman <khilman@kernel.org>
Cc: Sudhir Sreedharan <ssreedharan@mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For console devices having UART_CAP_SLEEP capability, the uart_pm_state has
to be initialized to UART_PM_STATE_ON. Otherwise the LCR regiser values
are reinitialized when uart_change_pm is called from uart_configure_port.
Signed-off-by: Sudhir Sreedharan <ssreedharan@mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
uart_set_termios() is called with interrupts enabled; no need to
save and restore the interrupt state when taking the uart port lock.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty->hw_stopped is not used by the tty core and is thread-unsafe;
hw_stopped is a member of a bitfield whose fields are updated
non-atomically and no lock is suitable for serializing updates.
Replace serial core usage of tty->hw_stopped with uport->hw_stopped.
Use int storage which works around Alpha EV4/5 non-atomic byte storage,
since uart_port uses different locks to protect certain fields within the
structure.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The serial core uses the tty port flags, ASYNC_CTS_FLOW and
ASYNC_CD_CHECK, to track whether CTS and DCD changes should be
ignored or handled. However, the tty port flags are not safe for
atomic bit operations and no lock provides serialized updates.
Introduce the struct uart_port status field to track CTS and DCD
enable states, and serialize access with uart port lock. Substitute
uart_cts_enabled() helper for tty_port_cts_enabled().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The serial core provides two helper functions, uart_handle_dcd_change()
and uart_handle_cts_change(), for UART drivers to use at interrupt
time. The serial core expects the UART driver to hold the uart port lock
when calling these helpers to prevent state corruption.
If lockdep enabled, trigger a warning if the uart port lock is not held
when calling these helper functions.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Prepare for spin lock assertion; move non-trivial assignment into
function body.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
uart_unthrottle() attempts to avoid sending START and the previous
x_char if the previous x_char has not yet been sent. However, this
optimization could leave the sender in a throttled state; for example,
if the sender is throttled and this unthrottle coincides with a manual
tcflow(TCION) from user-space, then neither START would be sent.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The UART driver is expected to clear port->x_char after
transmission while holding the port->lock. However, the serial
core fails to take the port->lock before assigning port->xchar.
This allows for the following race
CPU 0 | CPU 1
|
| serial8250_handle_irq
| ...
| serial8250_tx_chars
| if (port->x_char)
| serial_out(up, UART_TX, port->x_char)
uart_send_xchar |
port->x_char = ch |
| port->x_char = 0
port->ops->start_tx() |
|
The x_char on CPU 0 will never be sent.
Take the port->lock in uart_send_xchar() before assigning port->x_char.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 06aa82e498.
This commit purports to enable auto CTS flow control for the 8250
UART driver. However, the 8250 UART driver already supports auto
CTS flow control via UART_CAP_AFE and UART_CAP_EFR. Indeed, this
patch introduces another DT attribute for which an existing firmware
flag already exists ("auto-flow-control"). Furthermore, the use of
UPF_HARD_FLOW requires the UART driver to define .throttle and
.unthrottle methods, neither of which are defined for the 8250 UART
driver (which will result in a NULL ptr dereference). Finally, this patch
supposes to fix existing bugs in the serial core for auto CTS-enabled
hardware, but does not include the class of hardware for which these
bugs exist.
CC: Murali Karicheri <m-karicheri2@ti.com>
CC: Rob Herring <robh+dt@kernel.org>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
printk replaced with corresponding dev_* .
fixed two broken user-visible strings used by the corresponding printk.
the null check for uport->dev and port->dev is removed as dev_* will check for
null while printing.
printing of dev_name(uport->dev) and dev_name(port->dev) also removed as those
are being printed by dev_* .
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
window:
Group changes to the device tree. In preparation for adding device tree
overlay support, OF_DYNAMIC is reworked so that a set of device tree
changes can be prepared and applied to the tree all at once. OF_RECONFIG
notifiers see the most significant change here so that users always get
a consistent view of the tree. Notifiers generation is moved from before
a change to after it, and notifiers for a group of changes are emitted
after the entire block of changes have been applied
Automatic console selection from DT. Console drivers can now use
of_console_check() to see if the device node is specified as a console
device. If so then it gets added as a preferred console. UART devices
get this support automatically when uart_add_one_port() is called.
DT unit tests no longer depend on pre-loaded data in the device tree.
Data is loaded dynamically at the start of unit tests, and then unloaded
again when the tests have completed.
Also contains a few bugfixes for reserved regions and early memory setup.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1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=8IFz
-----END PGP SIGNATURE-----
Merge tag 'devicetree-for-linus' of git://git.secretlab.ca/git/linux
Pull device tree updates from Grant Likely:
"The branch contains the following device tree changes the v3.17 merge
window:
Group changes to the device tree. In preparation for adding device
tree overlay support, OF_DYNAMIC is reworked so that a set of device
tree changes can be prepared and applied to the tree all at once.
OF_RECONFIG notifiers see the most significant change here so that
users always get a consistent view of the tree. Notifiers generation
is moved from before a change to after it, and notifiers for a group
of changes are emitted after the entire block of changes have been
applied
Automatic console selection from DT. Console drivers can now use
of_console_check() to see if the device node is specified as a console
device. If so then it gets added as a preferred console. UART
devices get this support automatically when uart_add_one_port() is
called.
DT unit tests no longer depend on pre-loaded data in the device tree.
Data is loaded dynamically at the start of unit tests, and then
unloaded again when the tests have completed.
Also contains a few bugfixes for reserved regions and early memory
setup"
* tag 'devicetree-for-linus' of git://git.secretlab.ca/git/linux: (21 commits)
of: Fixing OF Selftest build error
drivers: of: add automated assignment of reserved regions to client devices
of: Use proper types for checking memory overflow
of: typo fix in __of_prop_dup()
Adding selftest testdata dynamically into live tree
of: Add todo tasklist for Devicetree
of: Transactional DT support.
of: Reorder device tree changes and notifiers
of: Move dynamic node fixups out of powerpc and into common code
of: Make sure attached nodes don't carry along extra children
of: Make devicetree sysfs update functions consistent.
of: Create unlocked versions of node and property add/remove functions
OF: Utility helper functions for dynamic nodes
of: Move CONFIG_OF_DYNAMIC code into a separate file
of: rename of_aliases_mutex to just of_mutex
of/platform: Fix of_platform_device_destroy iteration of devices
of: Migrate of_find_node_by_name() users to for_each_node_by_name()
tty: Update hypervisor tty drivers to use core stdout parsing code.
arm/versatile: Add the uart as the stdout device.
of: Enable console on serial ports specified by /chosen/stdout-path
...
Current code allocates too much data for tty_groups member of uart_port struct,
so fix it.
Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Some serial drivers (like 8250), want to add sysfs files. We need to do
so in a race-free way, so allow any port to be able to specify an
attribute group that should be added at device creation time.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Uart port drivers may reconfigure termios settings based on available
hardware support; set/clear ASYNC_CTS_FLOW and ASYNC_CHECK_CD _after_
calling the port driver's .set_termios method.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since at least before 2.6.30, it has not been possible to observe
a hung up file pointer in a tty driver's open() method unless/until
the driver open() releases the tty_lock() (eg., before blocking).
This is because tty_open() adds the file pointer while holding
the tty_lock() _and_ doesn't release the lock until after calling
the tty driver's open() method. [ Before tty_lock(), this was
lock_kernel(). ]
Since __tty_hangup() first waits on the tty_lock() before
enumerating and hanging up the open file pointers, either
__tty_hangup() will wait for the tty_lock() or tty_open() will
not yet have added the file pointer. For example,
CPU 0 | CPU 1
|
tty_open | __tty_hangup
.. | ..
tty_lock | ..
tty_reopen | tty_lock / blocks
.. |
tty_add_file(tty, filp) |
.. |
tty->ops->open(tty, filp) |
tty_port_open |
tty_port_block_til_ready |
.. |
while (1) |
.. |
tty_unlock | / unblocks
schedule | for each filp on tty->tty_files
| f_ops = tty_hung_up_fops;
| ..
| tty_unlock
tty_lock |
.. |
tty_unlock |
Note that since tty_port_block_til_ready() and similar drop
the tty_lock while blocking, when woken, the file pointer
must then be tested for having been hung up.
Also, fix bit-rotted drivers that used extra_count to track the
port->count bump.
CC: Mikael Starvik <starvik@axis.com>
CC: Samuel Ortiz <samuel@sortiz.org>
CC: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty->closing informs the line discipline that the hardware will
be shutting down imminently, and to disable further input other
than soft flow control (but to still allow additional output).
However, the tty lock is the necessary lock for preventing
concurrent changes to tty->closing. As shown by the call-tree
audit [1] of functions that modify tty->closing, the tty lock
is already held for those functions.
[1]
Call-tree audit of functions that modify tty->closing
* does not include call tree to tty_port_close(), tty_port_close_start(),
or tty_port_close_end() which is already documented in
'tty: Document locking for tty_port_close{,start,end}' that shows
callers to those 3 functions hold the tty lock
tty_release()
tty->ops->close() --+
|
__tty_hangup() |
tty->ops->close() --+
|
mp_close():drivers/staging/sb105x/sb_pci_mp.c
dngc_tty_close():drivers/staging/dgnc/dgnc_tty.c
dgap_tty_close():drivers/staging/dgap/dgap_tty.c
dgrp_tty_close():drivers/staging/dgrp/dgrp_tty.c
rp_close():drivers/tty/rocket.c
hvsi_close():drivers/tty/hvc/hvsi.c
rs_close():drivers/tty/serial/68328serial.c
rs_close():drivers/tty/serial/crisv10.c
uart_close():drivers/tty/serial/serial_core.c
isdn_tty_close():drivers/isdn/i4l/isdn_tty.c
tty3215_close():drivers/s390/char/con3215.c
tty_open()
tty_ldisc_setup() ----+
|
__tty_hangup() |
tty_ldisc_hangup() ---+
|
tty_set_ldisc() --------+
tty_ldisc_restore() --+
|
+- tty_ldisc_open()
ld->ops->open() --+
|
+- n_tty_open()
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a tty is opened for the serial console, the termios c_cflag
settings are inherited from the console line settings.
However, if the tty is subsequently closed, the termios settings
are lost. This results in a garbled console if the console is later
suspended and resumed.
Preserve the termios c_cflag for the serial console when the tty
is shutdown; this reflects the most recent line settings.
Fixes: Bugzilla #69751, 'serial console does not wake from S3'
Reported-by: Valerio Vanni <valerio.vanni@inwind.it>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch makes enable_ms() optional, so we can eliminate a lot of
empty enable_ms() implementations from driver code.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the devicetree specifies a serial port as a stdout device, then the
kernel can use it as the default console if nothing else was selected on
the command line. For any serial port that uses the uart_add_one_port()
feature, the uart_add_one_port() has all the information needed to
automatically enable the console device, which is what this patch does.
With this change applied, a device tree platform can be booted without
any console= parameters on the command line and the kernel will still be
able to determine its console.
Tested on QEMU Versatile model and i.MX
Signed-off-by: Grant Likely <grant.likely@linaro.org>
Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
8250 uart driver currently supports only software assisted hw flow
control. The software assisted hw flow control maintains a hw_stopped
flag in the tty structure to stop and start transmission and use modem
status interrupt for the event to drive the handshake signals. This is
not needed if hw has flow control capabilities. This patch adds a
DT attribute for enabling hw flow control for a uart port. Also skip
stop and start if this flag is present in flag field of the port
structure.
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
CC: Rob Herring <robh+dt@kernel.org>
CC: Pawel Moll <pawel.moll@arm.com>
CC: Mark Rutland <mark.rutland@arm.com>
CC: Ian Campbell <ijc+devicetree@hellion.org.uk>
CC: Kumar Gala <galak@codeaurora.org>
CC: Randy Dunlap <rdunlap@infradead.org>
CC: Jiri Slaby <jslaby@suse.cz>
CC: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In (efe2f29 kgdboc,kdb: Allow kdb to work on a non open console port)
support was added to directly use the "write_char" functions when
doing kdb over a non-open console port. This is great, but it ends up
bypassing the normal code in uart_console_write() that adds a carriage
return before any newlines.
There appears to have been a trend to add this support directly in
some console driver's poll_put_char() functions. This had a few side
effects, including:
- In this case we were doing LFCR, not CRLF. This was fixed in
uart_console_write() back in (d358788 [SERIAL] kernel console should
send CRLF not LFCR)
- Not all serial drivers had the LFCR code in their poll_put_char()
functions. In my case I was running serial/samsung.c which lacked
it.
I've moved the handling to uart_poll_put_char() to fix the above
problems. Now when I use kdb (and don't point console= to the same
UART) I no longer get:
[0]kdb>
[0]kdb>
[0]kdb>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
While porting a RS485 driver from 2.6.29 to 3.14, i noticed that the serial tty
driver could break it by using uart ports that it does not own :
1. uart_change_pm ist called during uart_open and calls the uart pm function
without checking for PORT_UNKNOWN.
The fix is to move uart_change_pm from uart_open to uart_port_startup.
2. The return code from the uart request_port call in uart_set_info is not
handled properly, leading to the situation that the serial driver also
thinks it owns the uart ports.
This can triggered by doing following actions :
setserial /dev/ttyS0 uart none # release the uart ports
modprobe lirc-serial # or any other device that uses the uart
setserial /dev/ttyS0 uart 16550 # gives no error and the uart tty driver
# can use the ports as well
Signed-off-by: Thomas Pfaff <tpfaff@pcs.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a serial port is closed, uart_close() takes care of shutting down the
hardware, and powering it down.
When a serial port is unbound while in use, uart_close() bypasses all of
this, as this is supposed to be done through uart_hangup() (invoked via
tty_vhangup() in uart_remove_one_port()).
However, uart_hangup() does not set the hardware's power state, leaving it
powered up. This may also lead to unbounded nesting counts in clock and
power management, depending on their internal implementation.
Make sure to power down the port in uart_hangup(), except when the port is
used as a serial console.
For serial consoles, this operation must be postponed until after the port
becomes completely unused. This case is not fixed yet, as it depends on a
(future) fix for the tty->count vs. port->count imbalance on failed
uart_open().
After this, the module clock used by the sh-sci driver is disabled on
unbind while the serial port is in use.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the serial_core ring buffer empties just as the tty layer receives
an XOFF, then start_tx will never be called when the tty layer
receives an XON as the serial_core ring buffer is empty. This will
possibly leave a few bytes trapped in the fifo for drivers that
disable the transmitter when flow controlled.
Signed-off-by: Seth Bollinger <sethb@digi.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When unbinding a serial driver that's being used as a serial console,
the kernel may crash with a NULL pointer dereference in a uart_*() function
called from uart_close () (e.g. uart_flush_buffer() or
uart_chars_in_buffer()).
To fix this, let uart_close() check for port->count == 0. If this is the
case, bail out early. Else tty_port_close_start() will make the port
counts inconsistent, printing out warnings like
tty_port_close_start: tty->count = 1 port count = 0.
and
tty_port_close_start: count = -1
and once uport == NULL, it will also crash.
Also fix the related crash in pr_debug() by checking for a non-NULL uport
first.
Detailed description:
On driver unbind, uart_remove_one_port() is called. Basically it;
- marks the port dead,
- calls tty_vhangup(),
- sets state->uart_port = NULL.
What will happen depends on whether the port is just in use by e.g. getty,
or was also opened as a console.
A. If the tty was not opened as a console:
- tty_vhangup() will (in __tty_hangup()):
- mark all file descriptors for this tty hung up by pointing them to
hung_up_tty_fops,
- call uart_hangup(), which sets port->count to 0.
- A subsequent uart_open() (this may be through /dev/ttyS*, or through
/dev/console if this is a serial console) will fail with -ENXIO as the
port was marked dead,
- uart_close() after the failed uart_open() will return early, as
tty_hung_up_p() (called from tty_port_close_start()) will notice it was
hung up.
B. If the tty was also opened as a console:
- tty_vhangup() will (in __tty_hangup()):
- mark non-console file descriptors for this tty hung up by pointing
them to hung_up_tty_fops,
- NOT call uart_hangup(), but instead call uart_close() for every
non-console file descriptor, so port->count will still have a
non-zero value afterwards.
- A subsequent uart_open() will fail with -ENXIO as the port was
marked dead,
- uart_close() after the failed uart_open() starts to misbehave:
- tty_hung_up_p() will not notice it was hung up,
- As port->count is non-zero, tty_port_close_start() will decrease
port->count, making the tty and port counts inconsistent. Later,
warnings like these will be printed:
tty_port_close_start: tty->count = 1 port count = 0.
and
tty_port_close_start: count = -1
- If all of this happens after state->uart_port was set to zero, a
NULL pointer dereference will happen.
Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the serial port being removed is used as a console, it must also be
unregistered from the console subsystem using unregister_console().
uart_ops.release_port() will release resources (e.g. iounmap() the serial
port registers), causing a crash on subsequent kernel output if the console
is still registered.
Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The uart_set_options() code unconditionally initalizes the spinlock
on the port. This can cause a deadlock in some situations.
One instance that exposed the problem, was when writing to
/sys/module/kgdboc/parameters/kgdboc to use ttyS0 when the console
is already running on ttyS0. If the spinlock is re-initialized
while the lock is held due to output to the console, there
is a deadlock.
Assume the spinlock is initialized if the port is a console.
Signed-off-by: Randy Witt <rewitt@declaratino.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Some serial ports will not use the standard base baud rate. Report
this after initialization so it might be discovered and used for early
console configuration.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Move "uart_console" definition to serial core header file, so that it can be
used by serial drivers.
Get rid of the uart_console defintion from mpc52xx_uart driver.
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Rajendra nayak <rnayak@ti.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Tested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Sourav Poddar <sourav.poddar@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull VFS updates from Al Viro,
Misc cleanups all over the place, mainly wrt /proc interfaces (switch
create_proc_entry to proc_create(), get rid of the deprecated
create_proc_read_entry() in favor of using proc_create_data() and
seq_file etc).
7kloc removed.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits)
don't bother with deferred freeing of fdtables
proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h
proc: Make the PROC_I() and PDE() macros internal to procfs
proc: Supply a function to remove a proc entry by PDE
take cgroup_open() and cpuset_open() to fs/proc/base.c
ppc: Clean up scanlog
ppc: Clean up rtas_flash driver somewhat
hostap: proc: Use remove_proc_subtree()
drm: proc: Use remove_proc_subtree()
drm: proc: Use minor->index to label things, not PDE->name
drm: Constify drm_proc_list[]
zoran: Don't print proc_dir_entry data in debug
reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show()
proc: Supply an accessor for getting the data from a PDE's parent
airo: Use remove_proc_subtree()
rtl8192u: Don't need to save device proc dir PDE
rtl8187se: Use a dir under /proc/net/r8180/
proc: Add proc_mkdir_data()
proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h}
proc: Move PDE_NET() to fs/proc/proc_net.c
...
The serial core uses device_find_child() but does not drop the reference to
the retrieved child after using it. This patch add the missing put_device().
What I have done to test this issue.
I used a machine with an AMBA PL011 serial driver. I tested the patch on
next-20120408 because the last branch [next-20120415] does not boot on this
board.
For test purpose, I added some pr_info() messages to print the refcount
after device_find_child() (lines: 1937,2009), and after put_device()
(lines: 1947, 2021).
Boot the machine *without* put_device(). Then:
echo reboot > /sys/power/disk
echo disk > /sys/power/state
[ 87.058575] uart_suspend_port:1937 refcount 4
[ 87.058582] uart_suspend_port:1947 refcount 4
[ 87.098083] uart_resume_port:2009refcount 5
[ 87.098088] uart_resume_port:2021 refcount 5
echo disk > /sys/power/state
[ 103.055574] uart_suspend_port:1937 refcount 6
[ 103.055580] uart_suspend_port:1947 refcount 6
[ 103.095322] uart_resume_port:2009 refcount 7
[ 103.095327] uart_resume_port:2021 refcount 7
echo disk > /sys/power/state
[ 252.459580] uart_suspend_port:1937 refcount 8
[ 252.459586] uart_suspend_port:1947 refcount 8
[ 252.499611] uart_resume_port:2009 refcount 9
[ 252.499616] uart_resume_port:2021 refcount 9
The refcount continuously increased.
Boot the machine *with* this patch. Then:
echo reboot > /sys/power/disk
echo disk > /sys/power/state
[ 159.333559] uart_suspend_port:1937 refcount 4
[ 159.333566] uart_suspend_port:1947 refcount 3
[ 159.372751] uart_resume_port:2009 refcount 4
[ 159.372755] uart_resume_port:2021 refcount 3
echo disk > /sys/power/state
[ 185.713614] uart_suspend_port:1937 refcount 4
[ 185.713621] uart_suspend_port:1947 refcount 3
[ 185.752935] uart_resume_port:2009 refcount 4
[ 185.752940] uart_resume_port:2021 refcount 3
echo disk > /sys/power/state
[ 207.458584] uart_suspend_port:1937 refcount 4
[ 207.458591] uart_suspend_port:1947 refcount 3
[ 207.498598] uart_resume_port:2009 refcount 4
[ 207.498605] uart_resume_port:2021 refcount 3
The refcount correctly handled.
Signed-off-by: Federico Vaga <federico.vaga@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The only part of proc_dir_entry the code outside of fs/proc
really cares about is PDE(inode)->data. Provide a helper
for that; static inline for now, eventually will be moved
to fs/proc, along with the knowledge of struct proc_dir_entry
layout.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
hardpps() functionality is provided through the N_PPS line
discipline now. The new function signature was added in commit
025b40ab (2011-01-12). There was no previous macro or
function hardpps(), at least since before the initial commit of
v2.6.12 in 2005. It's unlikely this code has been compiled since.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: George Spelvin <linux@horizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
An extension of the previous commit, there is no semantic change
here, just fewer lines of source code.
Signed-off-by: George Spelvin <linux@horizon.com>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The PPS (Pulse-Per-Second) line discipline has developed a number of
unhealthy attachments to core tty data and functions, ultimately leading
to its breakage.
The previous patches fixed the crashing. This one reduces coupling further
by eliminating the timestamp parameter from the dcd_change ldisc method.
This reduces header file linkage and makes the extension more generic,
and the timestamp read is delayed only slightly, from just before the
ldisc->ops->dcd_change method call to just after.
Fix attendant build breakage in
drivers/tty/n_tty.c
drivers/tty/tty_buffer.c
drivers/staging/speakup/selection.c
drivers/staging/dgrp/dgrp_*.c
Cc: William Hubbs <w.d.hubbs@gmail.com>
Cc: Chris Brannon <chris@the-brannons.com>
Cc: Kirk Reiser <kirk@braille.uwo.ca>
Cc: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: George Spelvin <linux@horizon.com>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
for extern function uart_remove_one_port:
need check pointer whether be NULL, before the main work.
just like what the other extern function uart_add_one_port has done.
uart_add_one_port and uart_remove_one_port are pair
information:
for the callers (such as drivers/tty/serial/jsm: jsm_tty.c, jsm_driver.c)
they realy assume that:
they still can call uart_remove_one_port, after uart_add_one_port failed
we (as an extern function), have to understand it (just like kfree).
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
One point is to have less places where we actually need tty pointer.
The other is that low_latency is bound to buffer processing and
buffers are now in tty_port. So it makes sense to move low_latency to
tty_port too.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.
tty_insert_flip_char is the next one to proceed. This one is used all
over the code, so the patch is huge.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The serial core is using power states lifted from ACPI for no
good reason. Remove this reference from the documentation and
alter all users to use an enum specific to the serial core
instead, and define it in <linux/serial_core.h>.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Alan Cox <alan@linux.intel.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull ARM OMAP serial updates from Russell King:
"This series is a major reworking of the OMAP serial driver code fixing
various bugs in the hardware-assisted flow control, extending up into
serial_core for a couple of issues. These fixes have been done as a
set of progressive changes and transformations in the hope that no new
bugs will be introduced by this series.
The problems are many-fold, from the driver not being informed about
updated settings, to the driver not knowing what the intentions of the
upper layers are.
The first four patches tackle the serial_core layer, allowing it to
provide the necessary information to drivers, and the remaining
patches allow the OMAP serial driver to take advantage of this.
This brings hardware assisted RTS/CTS and XON/OFF flow control into a
useful state.
These patches have been in linux-next for most of the last cycle;
indeed they predate the previous merge window. They've also been
posted to the OMAP people."
* 'omap-serial' of git://git.linaro.org/people/rmk/linux-arm: (21 commits)
SERIAL: omap: fix hardware assisted flow control
SERIAL: omap: simplify (2)
SERIAL: omap: move xon/xoff setting earlier
SERIAL: omap: always set TCR
SERIAL: omap: simplify
SERIAL: omap: don't read back LCR/MCR/EFR
SERIAL: omap: serial_omap_configure_xonxoff() contents into set_termios
SERIAL: omap: configure xon/xoff before setting modem control lines
SERIAL: omap: remove OMAP_UART_SYSC_RESET and OMAP_UART_FIFO_CLR
SERIAL: omap: move driver private definitions and structures to driver
SERIAL: omap: remove 'irq_pending' bitfield
SERIAL: omap: fix MCR TCRTLR bit handling
SERIAL: omap: fix set_mctrl() breakage
SERIAL: omap: no need to re-read EFR
SERIAL: omap: remove setting of EFR SCD bit
SERIAL: omap: allow hardware assisted IXANY mode to be disabled
SERIAL: omap: allow hardware assisted rts/cts modes to be disabled
SERIAL: core: add throttle/unthrottle callbacks for hardware assisted flow control
SERIAL: core: add hardware assisted h/w flow control support
SERIAL: core: add hardware assisted s/w flow control support
...
Conflicts:
drivers/tty/serial/omap-serial.c
serial_core.c usually does
if (HIGH_BITS_OFFSET)
expr-involving-HIGH_BITS_OFFSET()
at least to avoid generating useless code on 32-bit machines, where
HIGH_BITS_OFFSET is zero. Do that in uart_get_attr_port().
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
After commit "TTY: move tty buffers to tty_port", the tty buffers are
not freed in some drivers. This is because tty_port_destructor is not
called whenever a tty_port is freed. This was an assumption I counted
with but was unfortunately untrue. So fix the drivers to fulfil this
assumption.
To be sure, the TTY buffers (and later some stuff) are gone along with
the tty_port, we have to call tty_port_destroy at tear-down places.
This is mostly where the structure containing a tty_port is freed.
This patch does exactly that -- put tty_port_destroy at those places.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Without this we will shift data into oblivion and give wrong results on
some configurations
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add two callbacks for hardware assisted flow control; we need to know
when the tty layers want us to stop and restart due to their buffer
levels.
Call a driver specific throttle/unthrottle function if and only if the
driver indicates that it is using an enabled hardware assisted flow
control method, otherwise fall back to the non-hardware assisted
methods.
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Ports which are handling h/w flow control in hardware must not have
their RTS state altered depending on the tty's hardware-stopped state.
Avoid this additional logic when setting the termios state.
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Ports which are capable of handling s/w flow control in hardware to
know when the s/w flow control termios settings are changed. Add a
flag to allow the low level serial drivers to indicate that they
support this, and these changes should be propagated to them.
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
We pass both port and state because the original caller had both to hand.
With all the attribute callers this won't be true so do the conversion in
the function itself.
The current callers all do lock/query/unlock. This won't be true for future
set based cases but there are plenty of get ones that will exist so split
the code with a helper for the future cases.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The two patches needed are now in the tree. The first added the sysfs
interface and directly accesses the uartclk. The second provides a
proper interface for getting the values.
Wire them together.
This formes a basis for both get and set methods for any of the other uart
properties and we can now fill them out further.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It was noticed that polling drivers (like KGDB) are not able to use
serial ports if the ports were not previously initialized via console.
I.e. when booting with console=ttyAMA0 kgdboc=ttyAMA0, everything works
fine, but with console=ttyFOO kgdboc=ttyAMA0, the kgdboc doesn't work.
This is because we don't initialize the hardware. Calling ->startup() is
not an option, because drivers request interrupts there, and drivers
fail to handle situations when tty isn't opened with interrupts enabled.
So, we have to implement a new callback (actually, tty_ops already have
a similar callback), which does everything needed to initialize just the
hardware.
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If a serial driver is called post hangup with a second DCD event then we
will attempt to get the ldisc of NULL. Check we have a tty before trying to
do anything with it.
This is still only safe within the uart layer if the caller holds the
relevant uart locks. We could do with a version where the tty is passed for
more general use.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Added tty_device_create_release() and bound to dev->release in
tty_register_device_attr().
Added tty_port_register_device_attr() and used in uart_add_one_port()
instead of tty_register_device_attr().
Signed-off-by: Tomas Hlavacek <tmshlvck@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Added file /sys/devices/.../tty/ttySX/uartclk to allow reading
uartclk value in struct uart_port in serial_core via sysfs.
tty_register_device() has been generalized and refactored in order
to add support for setting drvdata and attribute_group to the device.
Signed-off-by: Tomas Hlavacek <tmshlvck@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sizeof when applied to a pointer typed expression gives the
size of the pointer.
Generated by: scripts/coccinelle/misc/noderef.cocci
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In most of the time, the driver needs to check if the cts flow control
is enabled. But now, the driver checks the ASYNC_CTS_FLOW flag manually,
which is not a grace way. So add a new wraper function to make the code
tidy and clean.
Signed-off-by: Huang Shijie <shijie8@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We want them split so that we can call them from setserial functionality
where we copy to/from user space and do the locking, but also from sysfs
where in future we'll want to came them within a sysfs context.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently we have no way to assign tty->port while performing tty
installation. There are two ways to provide the link tty_struct =>
tty_port. Either by calling tty_port_install from tty->ops->install or
tty_port_register_device called instead of tty_register_device when
the device is being set up after connected.
In this patch we modify most of the drivers to do the latter. When the
drivers use tty_register_device and we have tty_port already, we
switch to tty_port_register_device. So we have the tty_struct =>
tty_port link for free for those.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This will let us sort out a whole pile of tty related races. The
alternative would be to keep points and refcount the termios objects.
However
1. They are tiny anyway
2. Many devices don't use the stored copies
3. We can remove a pty special case
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, serial drivers don't report buffer overruns. When a buffer overrun
occurs, tty_insert_flip_char returns 0, and no attempt is made to insert that
same character again (i.e. it is lost). This patch reports buffer overruns via
the buf_overrun field in the port's icount structure.
Signed-off-by: Corbin Atkinson <corbin.atkinson@xxxxxx>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 642180871b.
Buffer overruns are for hardware reported overruns, not software ones,
which will only happen if we run out of memory and you will get lots of
-ENOMEM errors at the same time.
Thanks to Alan Cox for catching this.
Reported-by: Alan Cox <alan@linux.intel.com>
Cc: Corbin Atkinson <corbinat@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is legitimate but because we don't clear the drv->state pointer in the
unregister code causes a bogus BUG().
Resolves-bug: https://bugzilla.kernel.org/show_bug.cgi?id=42880
Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, serial drivers don't report buffer overruns. When a buffer overrun
occurs, tty_insert_flip_char returns 0, and no attempt is made to insert that
same character again (i.e. it is lost). This patch reports buffer overruns via
the buf_overrun field in the port's icount structure.
Signed-off-by: Corbin Atkinson <corbin.atkinson@ni.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
All num, magic and owner are set by alloc_tty_driver. No need to
re-set them on each allocation site.
pti driver sets something different to what it passes to
alloc_tty_driver. It is not a bug, since we don't use the lines
parameter in any way. Anyway this is fixed, and now we do the right
thing.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The synchronize_rcu() call resulting from making every serial driver
wake-up capable (commit b3b708fa) slows boot down on my Tegra2x system
(with CONFIG_PREEMPT disabled).
But this is avoidable since it is the device_set_wakeup_enable() and then
subsequence disable which causes the delay. We might as well just make
the device wakeup capable but not actually enable it for wakeup until
needed.
Effectively the current code does this:
device_set_wakeup_capable(dev, 1);
device_set_wakeup_enable(dev, 1);
device_set_wakeup_enable(dev, 0);
We can just drop the last two lines.
Before this change my boot log says:
[ 0.227062] Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
[ 0.702928] serial8250.0: ttyS0 at MMIO 0x70006040 (irq = 69) is a Tegra
after:
[ 0.227264] Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
[ 0.227983] serial8250.0: ttyS0 at MMIO 0x70006040 (irq = 69) is a Tegra
for saving of 450ms.
Suggested-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Extract ASYNC_INITIALIZED/TTY_IO_ERROR handling from uart_startup.
This will be useful for tty port helpers. These flags are handled
by the helpers instead.
So we create a new function uart_port_startup without touching these
flags there. And we keep uart_startup with the exact behavior as
before. We need that one because we start/stop the device from other
paths than open/close/hangup.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Let's fill the port_ops->shutdown. We will need this for hangup and
close port helpers.
We don't need to touch DTR/RTS registers in uart_port_shutdown. They
are set to off from port_close_start properly already.
Also we don't need to pin the TTY_IO_ERROR bit. This will be done in
close/hangup paths.
We leave uart_shutdown as is, because it is used (and will be) from
several paths now. Like from suspend.
The point is to not touch ASYNC_INITIALIZED bit. It will be set (and
checked) properly by the tty port helpers.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This is a preparation for the next patches which will move the stuff
from uart_open and uart_close/hangup here. Then we will use
tty_port_* helpers.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We need to expand uart_get into uart_open. We need it to move on with
conversion to use tty_port_open helper. After we do this, the code
will be much more similar to what tty_port_open does.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
It is not used at all, so no need to play any games with that.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Just put a kernel-doc comment to uart_change_pm and uart_insert_char.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
After the previous patches, the code is almost identical. There are
few differences in the helper code:
1) flush_buffer when flow_stopped
* when a user doesn't care about the data, delete it anyways
2) ASYNCB_INITIALIZED test before wait_until_sent_from
* obviously, there is nothing to wait for if the port is dead
3) drain_delay wait
* we don't set drain_delay
So we can use the helper now. It indeed removes a bunch of duplicated
code.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
As the tty_port helpers think closing_wait and close_delay are in
jiffies and we want to use the helpers (next patches), we have to
switch the closing_wait and close_delay from ms to jiffies now.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
There are some functions (uart_handle_dcd_change, _handle_cts_change,
_insert_char) which are big enough to not be inlined. So move them
from .h to .c. We need to export them so that modules can actually use
them.
They will be even bigger when we introduce tty refcounting to them.
While at it, cleanup the "Proud member of Uglyhacks'R'US". It means,
define uart_handle_sysrq_char only when SUPPORT_SYSRQ is set.
Otherwise define it as a macro. This is needed for some arm driver
where the second parameter is undefined if expanded.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (79 commits)
TTY: serial_core: Fix crash if DCD drop during suspend
tty/serial: atmel_serial: bootconsole removed from auto-enumerates
Revert "TTY: call tty_driver_lookup_tty unconditionally"
tty/serial: atmel_serial: add device tree support
tty/serial: atmel_serial: auto-enumerate ports
tty/serial: atmel_serial: whitespace and braces modifications
tty/serial: atmel_serial: change platform_data variable name
tty/serial: RS485 bindings for device tree
TTY: call tty_driver_lookup_tty unconditionally
TTY: pty, release tty in all ptmx_open fail paths
TTY: make tty_add_file non-failing
TTY: drop driver reference in tty_open fail path
8250_pci: Fix kernel panic when pch_uart is disabled
h8300: drivers/serial/Kconfig was moved
parport_pc: release IO region properly if unsupported ITE887x card is found
tty: Support compat_ioctl get/set termios_locked
hvc_console: display printk messages on console.
TTY: snyclinkmp: forever loop in tx_load_dma_buffer()
tty/n_gsm: avoid fifo overflow in gsm_dlci_data_output
tty/n_gsm: fix a bug in gsm_dlci_data_output (adaption = 2 case)
...
Fix up Conflicts in:
- drivers/tty/serial/8250_pci.c
Trivial conflict with removed duplicate device ID
- drivers/tty/serial/atmel_serial.c
Annoying silly conflict between "specify the port num via
platform_data" and other changes to atmel_console_init
This crash was showing up 100% of the time on Tegra CPUs when an
agetty was running on the serial port and the console was not running
on the serial port. The reason the Tegra saw it so reliably is that
the Tegra CPU internally ties DTR to DCD/DSR. That means when we
dropped DTR during suspend we would get always get an immediate DCD
drop.
The specific order of operations that were running:
* uart_suspend_port() would be called to put the uart in suspend mode
* we'd drop DTR (ops->set_mctrl(uport, 0)).
* the DTR drop would be looped back in the CPU to be a DCD drop.
* the DCD drop would look to the serial driver as a hangup
* the hangup would call uart_shutdown()
* ... suspend / resume happens ...
* uart_resume_port() would be called and run the code in the
(port->flags & ASYNC_SUSPENDED) block, which would startup the port
(and enable tx again).
* Since the UART would be available for tx, we'd immediately get
an interrupt, eventually calling transmit_chars()
* The transmit_chars() function would crash. The first crash would
be a dereference of a NULL tty member, but since the port has been
shutdown that was just a symptom.
I have proposed a patch that would fix the Tegra CPUs here (see
https://lkml.org/lkml/2011/10/11/444 - tty/serial: Prevent drop of DCD
on suspend for Tegra UARTs). However, even with that fix it is still
possible for systems that have an externally visible DCD line to see a
crash if the DCD drops at just the right time during suspend: thus
this patch is still useful.
Signed-off-by: Doug Anderson <dianders@chromium.org>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The following patch removed uart_change_pm() in uart_resume_port():
commit 5933a161ab
Author: Yin Kangkai <kangkai.yin@linux.intel.com>
serial-core: reset the console speed on resume
It will break the pxa serial driver when the system resumes from suspend mode
as it will try to set baud rate divider register in set_termios but with
clock off. The register value can not be set correctly on some platform if
the clock is disabled. The pxa driver will check the value and report the
following warning:
------------[ cut here ]------------
WARNING: at drivers/tty/serial/pxa.c:545 serial_pxa_set_termios+0x1dc/0x250()
Modules linked in:
[<c0281f30>] (unwind_backtrace+0x0/0xf0) from [<c029341c>] (warn_slowpath_common+0x4c/0x64)
[<c029341c>] (warn_slowpath_common+0x4c/0x64) from [<c029344c>] (warn_slowpath_null+0x18/0x1c)
[<c029344c>] (warn_slowpath_null+0x18/0x1c) from [<c044b1e4>] (serial_pxa_set_termios+0x1dc/0x250)
[<c044b1e4>] (serial_pxa_set_termios+0x1dc/0x250) from [<c044a840>] (uart_resume_port+0x128/0x2dc)
[<c044a840>] (uart_resume_port+0x128/0x2dc) from [<c044bbe0>] (serial_pxa_resume+0x18/0x24)
[<c044bbe0>] (serial_pxa_resume+0x18/0x24) from [<c0454d34>] (platform_pm_resume+0x40/0x4c)
[<c0454d34>] (platform_pm_resume+0x40/0x4c) from [<c0457ebc>] (pm_op+0x68/0xb4)
[<c0457ebc>] (pm_op+0x68/0xb4) from [<c0458368>] (device_resume+0xb0/0xec)
[<c0458368>] (device_resume+0xb0/0xec) from [<c04584c8>] (dpm_resume+0xe0/0x194)
[<c04584c8>] (dpm_resume+0xe0/0x194) from [<c0458588>] (dpm_resume_end+0xc/0x18)
[<c0458588>] (dpm_resume_end+0xc/0x18) from [<c02c518c>] (suspend_devices_and_enter+0x16c/0x1ac)
[<c02c518c>] (suspend_devices_and_enter+0x16c/0x1ac) from [<c02c5278>] (enter_state+0xac/0xdc)
[<c02c5278>] (enter_state+0xac/0xdc) from [<c02c48ec>] (state_store+0xa0/0xbc)
[<c02c48ec>] (state_store+0xa0/0xbc) from [<c0408f7c>] (kobj_attr_store+0x18/0x1c)
[<c0408f7c>] (kobj_attr_store+0x18/0x1c) from [<c034a6a4>] (sysfs_write_file+0x108/0x140)
[<c034a6a4>] (sysfs_write_file+0x108/0x140) from [<c02fb798>] (vfs_write+0xac/0x134)
[<c02fb798>] (vfs_write+0xac/0x134) from [<c02fb8cc>] (sys_write+0x3c/0x68)
[<c02fb8cc>] (sys_write+0x3c/0x68) from [<c027c700>] (ret_fast_syscall+0x0/0x2c)
---[ end trace 88289eceb4675b04 ]---
This patch fix the problem by adding the power on opertion back for uart
console when console_suspend_enabled is true.
Signed-off-by: Ning Jiang <ning.jiang@marvell.com>
Tested-by: Mayank Rana <mrana@codeaurora.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Let's use the newly added helper to avoid stalls in drivers which are
not yet ported to tty_port helpers.
Those which are broken (call tty_wait_until_sent with irqs disabled)
are left untouched. They are in a deeper trouble than we are trying to
solve here. This includes amiserial, 68328serial, 68360serial and
crisv10.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
So now, when we handle CLOSING flag, there is no point to hold
port->mutex over the start of uart_close.
Yes, there are still several things to reason about:
* port->count etc is and always was protected by a spinlock
* ->stop_rx is protected by a spinlock. Otherwise it would
race with interrupts.
* uart_wait_until_sent -- that one is already called without
port->mutex from set_termios and tty_set_ldisc. Should anything
be protected there, it would be tx_empty. And by a spinlock.
8250 does this internally...
This step is needed to fix system stalls. To not create an AB-BA lock
dependency (see next patches).
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We need to move port->mutex locking after wait_until_sent in
uart_close (for rationale see next patches). But if we did it now, we
would introduce a race between close and open. This is exactly why
port->mutex is locked at the top of uart_close.
To avoid the race, we add ASYNCB_CLOSING to uart_close. Like every
other sane TTY driver. Thanks to tty_port_block_til_ready used in
uart_open we will have this for free. Then we can move the port->mutex
lock.
Also note that this will make the conversion to tty_port helpers
easier. They are currently handling ASYNC_CLOSING flag correctly.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Now that platforms can override the port IRQ handler and the only user
of these UPIO modes has been converted over, kill off UPIO_DWAPB and
UPIO_DWAPB32.
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We used it really only serial and ami_serial. The rest of the
callsites were BUG/WARN_ONs to check if BTM is held. Now that we
pruned tty_locked from both of the real users, we can get rid of
tty_lock along with __big_tty_mutex_owner.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
tty_wakeup can be called from any context. So there is no need to have
an extra tasklet for calling that. Hence save some space and remove
the tasklet completely.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
During the BKL removal process, the BKL was switched to tty_lock
(BTM). Now we should start pruning the BTM further. Let's start with
wait_until_sent of the serial layer. This will allow us to switch to
the tty port helpers and thus clean it up much.
In wait_until_sent there are some uport members accessed, but neither
of them is protected by BTM at the location they are set ('=>' means
function call):
* uport->fifosize (set in tty_ioctl => uart_ioctl => uart_set_info)
* uport->type (set in add_one_port prior to tty_register_device)
* uport->timeout (set usually in tty_ioctl => tty_mode_ioctl =>
tty_set_termios => uart_set_termios => uart_change_speed =>
uport->ops->set_termios => uart_update_timeout)
* call to uport->ops->tx_empty()
If the tx_empty hook needs some lock to protect accesses to registers,
it should take &uport->lock spinlock like 8250 does. Otherwise there
still might be races e.g. with ISRs.
This should also fix the issue Andreas is seeing (BTM in comparison to
BKL doesn't have any hidden functionality like unlocking during
sleeping).
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
References: https://lkml.org/lkml/2011/5/25/562
Cc: Alan Cox <alan@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andreas Bombe <aeb@debian.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When a user has SYS_ADMIN capabilities and uart->ops->startup returns
an error in uart_startup, we silently drop the error. We then return 0
and behave as if it didn't fail. (Not quite, since we set TTY_IO_ERROR
bit and leave ASYNC_INITIALIZED bit cleared.)
This all is to allow setserial to work with improperly configured or
unconfigured ports. User can thus set port properties and reconfigure
properly.
This patch only documents this behavior.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Russel King <linux@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
msleep* is guaranteed to return with TASK_RUNNING task state. And
since there is no other set_task_state in the paths of
uart_wait_until_sent, we need not to set_task_state to TASK_RUNNING.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
tty->index (named here as line) is set up in initialize_tty_struct.
The value is checked in get_tty_driver for the found driver as:
if (device < base || device >= base + p->num)
continue;
*index = device - base;
So index/line can never be more than driver->num. Hence remove this
test from uart_open.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
remove invalid location line in each file header after location
moved from driver/char to driver/tty
Signed-off-by: Jovi Zhang <bookjovi@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Now, uart_update_termios is empty, so it's time to remove it. We no
longer need a live tty in .dtr_rts. So this should prune all the bugs
where tty is zeroed in port->tty during tty_port_block_til_ready.
There is one thing to note. We don't set ASYNC_NORMAL_ACTIVE now. It's
because this is done already in tty_port_block_til_ready.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
In .dtr_rts we do:
uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS)
and call uart_update_termios. It does:
uart_set_mctrl(port, TIOCM_DTR | TIOCM_RTS)
once again. As the only callsite of uart_update_termios is .dtr_rts,
remove the uart_set_mctrl from uart_update_termios to not set it twice.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We should not fiddle with speed and cflags in .dtr_rts hook. Actually
we might not have tty at that moment already.
So move the console cflag copy and speed setup into uart_startup.
Actually the speed setup is already there, but we need to call it
unconditionally (uart_startup is called from uart_open with hw_init =
0).
This means we move uart_change_speed before dtr/rts setup in .dtr_rts.
But this should not matter as the setup should be called after
uart_change_speed anyway.
Before: After:
dtr/rts setup (dtr_rts) uart_change_speed (startup)
uart_change_speed (update_termios) dtr/rts setup (dtr_rts)
dtr/rts setup (update_termios) dtr/rts setup (update_termios)
The second setup will dismiss with the next patch.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Only oddities here are a couple of drivers that bogusly called the ldisc
helpers instead of returning -ENOIOCTLCMD. Fix the bug and the rest goes
away.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Doing tiocmget was such fun we should do tiocmset as well for the same
reasons
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We don't actually need this and it causes problems for internal use of
this functionality. Currently there is a single use of the FILE * pointer.
That is the serial core which uses it to check tty_hung_up_p. However if
that is true then IO_ERROR is also already set so the check may be removed.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Peter Hurley