per CodingStyle we should have those braces, no
functional changes.
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 0324a82102.
That commit tried to fix a deadlock problem when using
hci_ldisc, but it turns out the bug was in hci_ldsic
all along where it was calling ->write() from within
->write_wakeup() callback.
The problem is that ->write_wakeup() was called with
port lock held and ->write() tried to grab the same
port lock.
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The lack of pm_runtime_resume handling for the device state leads into
device wake-up interrupts not working after a while for runtime PM.
Also, serial-omap is confused about the use of device_may_wakeup.
The checks for device_may_wakeup should only be done for suspend and
resume, not for pm_runtime_suspend and pm_runtime_resume. The wake-up
events for PM runtime should always be enabled.
The lack of pm_runtime_resume handling leads into device wake-up
interrupts not working after a while for runtime PM.
Rather than try to patch over the issue of adding complex tests to
the pm_runtime_resume, let's fix the issues properly:
1. Make serial_omap_enable_wakeup deal with all internal PM state
handling so we don't need to test for up->wakeups_enabled elsewhere.
Later on once omap3 boots in device tree only mode we can also
remove the up->wakeups_enabled flag and rely on the wake-up
interrupt enable/disable state alone.
2. Do the device_may_wakeup checks in suspend and resume only,
for runtime PM the wake-up events need to be always enabled.
3. Finally just call serial_omap_enable_wakeup and make sure we
call it also in pm_runtime_resume.
4. Note that we also have to use disable_irq_nosync as serial_omap_irq
calls pm_runtime_get_sync.
Fixes: 2a0b965cfb (serial: omap: Add support for optional wake-up)
Cc: stable@vger.kernel.org # v3.13+
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Provided that the SER_RS485_RX_DURING_TX flag is not set, empty the
RX FIFO to prevent reading back the transmitted data.
Signed-off-by: Dimitris Lampridis <dlampridis@logikonlabs.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Make sure that serial_omap_stop_rx() also disables RDI (Receiver Data Interrupt),
otherwise the interrupt handler will call serial_omap_rdi() to read the new data,
resulting in the transmission being echoed back.
When the half-duplex transmission is complete, in order to reverse the effects of
serial_omap_stop_rx(), we should re-enable:
* the RX interrupts _without_ overwriting up->ier
* the UART_LSR_DR bit of the up->port.read_status_mask
Signed-off-by: Dimitris Lampridis <dlampridis@logikonlabs.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the gpio is not yet available we better also
defer the probing in the rs485 case.
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently the info message about a missing wakeirq for uart is printed
every time the serial driver's startup function is called. This happens
multiple times and not just once.
This can cause lots of extra messages at boot time, slowing things down. It is
caused by commit 2a0b965cfb (serial: omap: Add support for optional wake-up)
which was applied for v3.13-rc1.
This patch moves the infomessage to the probe function to display it
only once.
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: stable <stable@vger.kernel.org> # 3.13
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If RS-485 is enabled, make the OMAP UART fire THR interrupts when both
TX FIFO and TX shift register are empty instead of polling the
equivalent status bit. This removes the burst of interrupt requests
seen at every end of transmission.
Also: the comment said that the TX FIFO trigger level was set at 16
characters when it's 32 in reality.
Signed-off-by: Philippe Proulx <philippe.proulx@savoirfairelinux.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
With the recent pinctrl-single changes, omaps can treat
wake-up events from deeper idle states as interrupts.
There's a separate "io chain" controller on most omaps
that stays enabled when the device hits off-idle and the
regular interrupt controller is powered off.
Let's add support for the optional second interrupt for
wake-up events. And then serial-omap can manage the
wake-up interrupt from it's runtime PM calls to avoid
spurious interrupts during runtime.
Note that the wake interrupt is board specific as it
uses the UART RX pin, and for omap3, there are six pin
options for UART3 RX pin.
Also Note that the legacy platform based booting handles
the wake-ups in the legacy mux driver and does not need to
pass the wake-up interrupt to the driver.
And finally, to pass the wake-up interrupt in the dts file,
either interrupt-map or the pending interrupts-extended
property needs to be passed. It's probably best to use
interrupts-extended when it's available.
Cc: Felipe Balbi <balbi@ti.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Reviewed-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This callback is unused by the serial core since pre-git days
and is not coming back. Delete it. Enabling wakeup on the
OMAP serial driver is done through other runpaths these days.
Cc: Tony Lindgren <tony@atomide.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Make Mode16 more preferred than Mode13, to match TRM baudrates table.
Signed-off-by: Alexey Pelykh <alexey.pelykh@gmail.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit c441508421.
Kevin writes:
Hmm, another OMAP serial patch that wasn't Cc'd to linux-omap
where OMAP users might have seen it. :(
I just bisected a strange problem in linux-next on OMAP3 down to
this patch. Reverting it fixes the problem.
On OMAP3530 Beagle and Overo, after boot, doing a 'cat
/proc/cpuinfo' was not returning to a prompt, suggesting
something strange with the FIFO. Hitting return gets me back to
a prompt.
Greg, this one should also be dropped from tty-next until it can
be further investgated and the problem solved.
Reported-by: Kevin Hilman <khilman@linaro.org>
Cc: Dmitry Fink <finik@ti.com>
Cc: Alexander Savchenko <oleksandr.savchenko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 908fd7e566.
Kevin writes:
Greg, without a better justification in the changelog, I think
this patch should be dropped from tty-next.
Reported-by: Kevin Hilman <khilman@linaro.org>
Cc: Ruchika Kharwar <ruchika@ti.com>
Cc: Alexander Savchenko <oleksandr.savchenko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The recent patch to add RS485 contained a bug whereby the IER
interrupt was cleared down incorrectly.
This patch fixes the problem.
Signed-off-by: Mark Jackson <mpfj@newflow.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch adds RS485 support to the OMAP serial driver, as
defined in:-
Documentation/devicetree/bindings/serial/rs485.txt
When a UART transmitter is connected to (eg) a RS485 driver, it is
necessary to turn the driver on/off as quickly as possible. This is
best achieved in the serial driver itself (rather than in userspace
where the latency can be quite large).
This patch allows a GPIO pin to be defined (via DT) that controls
the enabling of the driver at the start of a message, and disables
the driver when the message has been completed.
When RS485 is disabled, the RTS pin is set to on.
Signed-off-by: Mark Jackson <mpfj@newflow.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If earlyprintk is enabled and current UART is console port the platform
code can mark it as RPM_ACTIVE to sync real IP state with PM Runtime and
avoid resuming of already active device, but now, driver initialization
will be performed in the wrong way:
pm_runtime_enable(&pdev->dev);
<-- PM runtime alowed (device state RPM_ACTIVE)
if (omap_up_info->autosuspend_timeout == 0)
omap_up_info->autosuspend_timeout = -1;
device_init_wakeup(up->dev, true);
pm_runtime_use_autosuspend(&pdev->dev);
<-- update_autosuspend() will be called and it will disable device
(device state RPM_SUSPENDED)
pm_runtime_set_autosuspend_delay(&pdev->dev,
omap_up_info->autosuspend_timeout);
<-- update_autosuspend() will be called which will re-enable device
(device state RPM_ACTIVE), because autosuspend_timeout < 0
pm_runtime_irq_safe(&pdev->dev);
pm_runtime_get_sync(&pdev->dev);
<-- will do nothing
Such behavior isn't expected by OMAP serial drivers and causes
unpredictable calls of serial_omap_runtime_suspend() and
serial_omap_runtime_resume().
Hence, fix it by allowing PM runtime only after all its parameters are
configured.
CC: Tony Lindgren <tony@atomide.com>
CC: Rajendra Nayak <rnayak@ti.com>
CC: Felipe Balbi <balbi@ti.com>
CC: Kevin Hilman <khilman@linaro.org>
Tested-by: Mark Jackson <mpfj-list@newflow.co.uk>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Otherwise serial driver would crash accessing platform_data that was
not initialized in functions like:
serial_omap_pm(...)
...
if (!state && pdata->enable_wakeup)
^^^^^^^
...
Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
Signed-off-by: Alexander Savchenko <oleksandr.savchenko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The revision register is a 32 bit register. The serial_in() function reads
only the lower 16 bits of the register. This leads to an incorrect computation
of the Module revision.
Signed-off-by: Ruchika Kharwar <ruchika@ti.com>
[oleksandr.savchenko@ti.com: add some whitespaces]
Signed-off-by: Alexander Savchenko <oleksandr.savchenko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Current logic results in interrupt storm since the fifo
is constantly below the threshold level. Change the logic
to fill all the available spaces in the fifo as long as
we have data to minimize the possibilty of underflow and
elimiate excessive interrupts.
Signed-off-by: Dmitry Fink <finik@ti.com>
Signed-off-by: Alexander Savchenko <oleksandr.savchenko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
wer has TX wakeup bit available enable the same
by populating the necessary tx wakeup flag for the
applicable module ip blocks and use the same
while configuaring wer reg.
Also wer is not context restored, restore wer when
context is lost.
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Kevin Hilman <kevin.hilman@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(for drivers/tty changes)
Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since commit ab78029 (drivers/pinctrl: grab default handles from device core),
we can rely on device core for setting the default pins. Compile tested only.
Acked-by: Linus Walleij <linus.walleij@linaro.org> (personally at LCE13)
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In the runtime_suspend function pdata is not being used, and
also blocks the function in device tree based booting. Fix it
by removing the unused pdata from the runtime_suspend function.
Further, context loss count is not being passed in pdata, so
let's just reinitialize the port every time for those case.
This can be further optimized later on for the device tree
case by adding detection for the hardware state and possibly
by adding a driver specific autosuspend timeout.
And doing this, we can then make the related dev_err into a
dev_dbg message instead of an error.
In order for the wake-up events to work, we also need to set
autosuspend_timeout to -1 if 0, and also device_init_wakeup()
as that's not being done by the platform init code for the
device tree case.
Note that this does not affect legacy booting, and in fact
might make it work for the cases where the context loss info
is not being passed in pdata.
Thanks to Kevin Hilman <khilman@linaro.org> for debugging
and suggesting fixes for the autosuspend_timeout and
device_init_wakeup() related initializiation.
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Tested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The dereference to 'up' should be moved below the NULL test.
Introduced by commit ddd85e225c
(serial: omap: prevent runtime PM for "no_console_suspend")
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
A recent bug fix in 3.10, ddd85e225c "serial: omap: prevent runtime PM for
"no_console_suspend"", introduced a regression from an obvious typo:
drivers/tty/serial/omap-serial.c:1677:14: error: 'serial_omap_complete'
undeclared here (not in a function)
This changes the incorrectly added macro to the one that we need instead.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Bin Liu <b-liu@ti.com>
Acked-by: Sourav Poddar<sourav.poddar@ti.com>
Tested-by: Sourav Poddar<sourav.poddar@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The driver manages "no_console_suspend" by preventing runtime PM
during the suspend path, which forces the console UART to stay awake.
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>
UART IP slave idle handling now taken care by runtime pm backend(hwmod layer)
so remove the hackery from the driver.
As discussed on the list, in future if dma mode needs to be brought
back to this driver, UART sysc handling needs to be updated in
framework such a way that no-idle/force idle profile can be supported.
Given the broken dma mode for OMAP uarts, its very unlikely.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tested-by: Vaibhav Bedia <vaibhav.bedia@ti.com>
Tested-by: Sourav Poddar <sourav.poddar@ti.com>
Signed-off-by: Rajendra nayak <rnayak@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Tested-by: Kevin Hilman <khilman@linaro.org> # OMAP4/Panda
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Partially reverts 1776fd059c
that introduced regression reported by Paul Walmsley.
This commit restores setting granularity in SCR register
and adds note about comments below being inconsistent with
actual code.
Signed-off-by: Alexey Pelykh <alexey.pelykh@gmail.com>
Tested-by: Paul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Original configuration of Rx FIFO threshold contained an error
that resulted Rx threshold to be effectively set to 1 character
instead of 16 characters, as noted in comments.
Checking LSR to contain UART_LSR_THRE bit set caused issue when
not all UART_IER_THRI interrupts have been properly handled.
This caused gap in Tx data, visible on high baud rates using
oscilloscope.
Setting OMAP_UART_SCR_TX_EMPTY bit in SCR caused UART_IER_THRI
interrupt to be raised only when Tx FIFO and Tx shift registers
are empty.
Signed-off-by: Alexey Pelykh <alexey.pelykh@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Original table in OMAP TRM named "UART Mode Baud Rates, Divisor
Values, and Error Rates" determines modes not for all common baud
rates. E.g. for 1000000 baud rate mode should be 16x, but according to
that table it's determined as 13x. According to current implementation
of mode divisor selection, after requesting 1000000 baudrate from
driver, later one will configure chip to use MODE13 divisor. Assuming
48Mhz as common UART clock speed, MODE13 divisor will effectively give
1230769 baudrate, what is quite far from desired 1000000 baudrate.
While with MODE16 divisor, chip will produce exact 1000000 baudrate.
In old driver that served UART devices (8250.c and serial_core.c) this
divisor could have been configured by user-space program, but in
omap_serial.c driver implementation this ability was not implemented
(afaik, by design) thus disallowing proper usage of MODE16-compatible
baudrates.
Signed-off-by: Alexey Pelykh <alexey.pelykh@gmail.com>
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.
Now, the one where most of tty_port_tty_get gets removed:
tty_flip_buffer_push.
IOW we also closed all the races in drivers not using tty_port_tty_get
at all yet.
Also we move tty_flip_buffer_push declaration from include/linux/tty.h
to include/linux/tty_flip.h to all others while we are changing it
anyway.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Some systems require the additional communication functionality of a
9-bit UART. For that we could use the "stick" (mark/space) parity
bit supported on omap serial device. When is set, if PARODD is set the
parity bit is always 1; if PARODD is not set, then the parity bit is
always 0.
Signed-off-by: Enric Balletbo i Serra <eballetbo@iseebcn.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We need to move this file to allow ARM multiplatform configurations
to build for omap2+. This can now be done as this file now only
contains platform_data.
cc: Russell King <linux@arm.linux.org.uk>
cc: Alan Cox <alan@linux.intel.com>
cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cc: Govindraj.R <govindraj.raja@ti.com>
cc: Kevin Hilman <khilman@ti.com>
cc: linux-serial@vger.kernel.org
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
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
CONFIG_HOTPLUG is going away as an option so __devexit is no
longer needed.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
Cc: Lucas Tavares <lucaskt@linux.vnet.ibm.com>
Cc: Daniel Walker <dwalker@fifo99.com>
Cc: Bryan Huntsman <bryanh@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Tony Prisk <linux@prisktech.co.nz>
Acked-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CONFIG_HOTPLUG is going away as an option so __devinit is no longer
needed.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Lucas Tavares <lucaskt@linux.vnet.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Tony Prisk <linux@prisktech.co.nz>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CONFIG_HOTPLUG is going away as an option so __devexit_p is no longer
needed.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Lucas Tavares <lucaskt@linux.vnet.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Tony Prisk <linux@prisktech.co.nz>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When the UART device has hardware flow control enabled, it ignores the
MCR RTS bit in the MCR register, and keeps RTS asserted as long as we
continue to read characters from the UART receiver FIFO. This means
that when the TTY buffers become full, the UART doesn't tell the remote
end to stop sending, which causes the TTY layer to start dropping
characters.
A similar problem exists with software flow control. We need the FIFO
register to fill when software flow control is enabled to provoke the
UART to send the XOFF character.
Fix this by implementing the throttle/unthrottle callbacks, and use
these to disable receiver interrupts. This in turn means that the UART
FIFO will fill, which will then cause the UART's hardware to deassert
the RTS signal and/or send the XOFF character, stopping the remote end.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Simplify:
- set ECB
...
- LCR mode A
- clear TCRTLR
- LCR mode B
- clear ECB
- set ECB and update other bits
- LCR mode A
- update XONANY
to:
- set ECB
...
- LCR mode B
- set ECB and update other bits
- LCR mode A
- update XONANY and clear TCRTLR
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Take advantage of the switch to mode B for accessing the TCR register,
and move the xon/xoff configuration there. This allows further
simplication of this sequence.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
We always setup the TCR register in the software flow control path,
and when hardware flow control is enabled. Remove this redundant
setup, and place it before we setup any hardware flow control.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
We have the sequence:
- LCR mode B
- write EFR with ECB clear
- LCR mode normal
- if s/w flow
- LCR mode B
- write EFR with ECB clear
...
- LCR mode B
- write EFR with ECB clear
- LCR mode normal
This can be simplified to:
- if s/w flow
- LCR mode B
- write EFR with ECB clear
...
- LCR mode B
- write EFR with ECB clear
- LCR mode normal
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
There's really no reason to read back these registers while setting
the termios modes, provided we keep our cached copies up to date.
Remove these readbacks.
This has the benefit that we know that the EFR_ECB and MCR_TCRTLR
bits will always be clear, so we don't need to keep masking these
bits throughout the code.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Felipe Balbi