linux-toradex.git/drivers/tty/serial/sa1100.c, branch v6.6

serial: drivers: switch ch and flag to u8

2023-07-25T17:21:04+00:00

Now that the serial layer explicitly expects 'u8' for flags and
characters, propagate this type to drivers' (RX) routines.

Note that amba-pl011's, clps711x's and st-asc's 'ch' are left unchanged
because 'ch' contains not only a character, but whole status.

Signed-off-by: Jiri Slaby (SUSE) 
Cc: Tobias Klauser 
Cc: Russell King 
Cc: Vineet Gupta 
Cc: Richard Genoud 
Cc: Nicolas Ferre 
Cc: Alexandre Belloni 
Cc: Claudiu Beznea 
Cc: Alexander Shiyan 
Cc: Baruch Siach 
Cc: "Maciej W. Rozycki" 
Cc: Taichi Sugaya 
Cc: Takao Orito 
Cc: Shawn Guo 
Cc: Sascha Hauer 
Cc: Pengutronix Kernel Team 
Cc: Fabio Estevam 
Cc: NXP Linux Team 
Cc: Kevin Cernekee 
Cc: Krzysztof Kozlowski 
Cc: Alim Akhtar 
Cc: Laxman Dewangan 
Cc: Thierry Reding 
Cc: Jonathan Hunter 
Cc: Palmer Dabbelt 
Cc: Paul Walmsley 
Cc: Orson Zhai 
Cc: Baolin Wang 
Cc: Chunyan Zhang 
Cc: Patrice Chotard 
Cc: Maxime Coquelin 
Cc: Alexandre Torgue 
Cc: Hammer Hsieh 
Acked-by: Richard GENOUD 
Acked-by: Tobias Klauser 
Acked-by: Thierry Reding 
Acked-by: Maciej W. Rozycki 
Link: https://lore.kernel.org/r/20230712081811.29004-11-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: serial: use uart_port_tx() helper

2022-11-03T02:32:40+00:00

uart_port_tx() is a new helper to send characters to the device. Use it
in these drivers.

Cc: Tobias Klauser 
Cc: Richard Genoud 
Cc: Nicolas Ferre 
Cc: Alexandre Belloni 
Cc: Claudiu Beznea 
Cc: Vladimir Zapolskiy 
Cc: Liviu Dudau 
Cc: Sudeep Holla 
Cc: Lorenzo Pieralisi 
Cc: Shawn Guo 
Cc: Sascha Hauer 
Cc: Pengutronix Kernel Team 
Cc: Fabio Estevam 
Cc: NXP Linux Team 
Cc: "Andreas Färber" 
Cc: Manivannan Sadhasivam 
Reviewed-by: Ilpo Järvinen 
Signed-off-by: Jiri Slaby (SUSE) 
Link: https://lore.kernel.org/r/20221004104927.14361-3-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

serial: Make ->set_termios() old ktermios const

2022-08-30T12:22:35+00:00

There should be no reason to adjust old ktermios which is going to get
discarded anyway.

Reviewed-by: Andy Shevchenko 
Signed-off-by: Ilpo Järvinen 
Link: https://lore.kernel.org/r/20220816115739.10928-7-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

drivers: tty: serial: Fix deadlock in sa1100_set_termios()

2022-04-22T14:23:37+00:00

There is a deadlock in sa1100_set_termios(), which is shown
below:

   (Thread 1)              |      (Thread 2)
                           | sa1100_enable_ms()
sa1100_set_termios()       |  mod_timer()
 spin_lock_irqsave() //(1) |  (wait a time)
 ...                       | sa1100_timeout()
 del_timer_sync()          |  spin_lock_irqsave() //(2)
 (wait timer to stop)      |  ...

We hold sport->port.lock in position (1) of thread 1 and
use del_timer_sync() to wait timer to stop, but timer handler
also need sport->port.lock in position (2) of thread 2. As a result,
sa1100_set_termios() will block forever.

This patch moves del_timer_sync() before spin_lock_irqsave()
in order to prevent the deadlock.

Signed-off-by: Duoming Zhou 
Link: https://lore.kernel.org/r/20220417111626.7802-1-duoming@zju.edu.cn
Signed-off-by: Greg Kroah-Hartman

serial: make uart_console_write->putchar()'s character an unsigned char

2022-03-03T14:06:31+00:00

Currently, uart_console_write->putchar's second parameter (the
character) is of type int. It makes little sense, provided uart_console_write()
accepts the input string as "const char *s" and passes its content -- the
characters -- to putchar(). So switch the character's type to unsigned
char.

We don't use char as that is signed on some platforms. That would cause
troubles for drivers which (implicitly) cast the char to u16 when
writing to the device. Sign extension would happen in that case and the
value written would be completely different to the provided char. DZ is
an example of such a driver -- on MIPS, it uses u16 for dz_out in
dz_console_putchar().

Note we do the char -> uchar conversion implicitly in
uart_console_write(). Provided we do not change size of the data type,
sign extension does not happen there, so the problem is void.

This makes the types consistent and unified with the rest of the uart
layer, which uses unsigned char in most places already. One exception is
xmit_buf, but that is going to be converted later.

Cc: Paul Cercueil 
Cc: Tobias Klauser 
Cc: Russell King 
Cc: Vineet Gupta 
Cc: Nicolas Ferre 
Cc: Alexandre Belloni 
Cc: Ludovic Desroches 
Cc: Florian Fainelli 
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: Alexander Shiyan 
Cc: Baruch Siach 
Cc: "Maciej W. Rozycki" 
Cc: Paul Walmsley 
Cc: Palmer Dabbelt 
Cc: Albert Ou 
Cc: Shawn Guo 
Cc: Sascha Hauer 
Cc: Pengutronix Kernel Team 
Cc: Fabio Estevam 
Cc: NXP Linux Team 
Cc: Karol Gugala 
Cc: Mateusz Holenko 
Cc: Vladimir Zapolskiy 
Cc: Neil Armstrong 
Cc: Kevin Hilman 
Cc: Jerome Brunet 
Cc: Martin Blumenstingl 
Cc: Taichi Sugaya 
Cc: Takao Orito 
Cc: Liviu Dudau 
Cc: Sudeep Holla 
Cc: Lorenzo Pieralisi 
Cc: "Andreas Färber" 
Cc: Manivannan Sadhasivam 
Cc: Michael Ellerman 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Andy Gross 
Cc: Bjorn Andersson 
Cc: Krzysztof Kozlowski 
Cc: Orson Zhai 
Cc: Baolin Wang 
Cc: Chunyan Zhang 
Cc: Patrice Chotard 
Cc: Maxime Coquelin 
Cc: Alexandre Torgue 
Cc: "David S. Miller" 
Cc: Peter Korsgaard 
Cc: Michal Simek 
Acked-by: Richard Genoud  [atmel_serial]
Acked-by: Uwe Kleine-König 
Acked-by: Paul Cercueil 
Acked-by: Neil Armstrong  # meson_serial
Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20220303080831.21783-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

serial: sa1100: drop low-latency workaround

2021-04-22T10:09:26+00:00

Commit 53e0e6706c76 ("tty: serial: sa1100: drop uart_port->lock before
calling tty_flip_buffer_push()") claimed to address a locking
issue but only provided a dubious lockdep splat from an unrelated
driver, which in the end turned out to be due a broken local change
carried by the author.

Unfortunately these patches were merged before the issue had been
analysed properly so the commit messages makes no sense whatsoever.

The real issue was first seen on RT which at the time effectively always
set the low_latency flag for all serial drivers by patching
tty_flip_buffer_push(). This in turn revealed that many drivers did not
handle the infamous low_latency behaviour which meant that data was
pushed immediately to the line discipline instead of being deferred to a
work queue.

Since commit a9c3f68f3cd8 ("tty: Fix low_latency BUG"),
tty_flip_buffer_push() always schedules a work item to push data to the
line discipline and there's no need to keep any low_latency hacks
around.

Link: https://lore.kernel.org/linux-serial/cover.1376923198.git.viresh.kumar@linaro.org/
Signed-off-by: Johan Hovold 
Link: https://lore.kernel.org/r/20210421095509.3024-21-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman

serial: sa1100: use platform_get_resource()

2020-08-18T13:02:06+00:00

Use platform_get_resource() to fetch the memory resource
instead of open-coded variant.

While here, fail the probe if no resource found or no port is added.

Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20200804134807.11589-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

tty/serial: Migrate sa1100 to use has_sysrq

2019-12-18T14:04:59+00:00

The SUPPORT_SYSRQ ifdeffery is not nice as:
- May create misunderstanding about sizeof(struct uart_port) between
  different objects
- Prevents moving functions from serial_core.h
- Reduces readability (well, it's ifdeffery - it's hard to follow)

In order to remove SUPPORT_SYSRQ, has_sysrq variable has been added.
Initialise it in driver's probe and remove ifdeffery.

Signed-off-by: Dmitry Safonov 
Link: https://lore.kernel.org/r/20191213000657.931618-37-dima@arista.com
Signed-off-by: Greg Kroah-Hartman

serial: sa1100: add note about modem control signals

2019-06-04T11:56:33+00:00

As suggested by Uwe, add a note indicating that the modem control
signals do not support interrupts, which precludes the driver from
using mctrl_gpio_init().

Suggested-by: Uwe Kleine-König 
Signed-off-by: Russell King

serial: sa1100: add support for mctrl gpios

2019-06-04T11:56:31+00:00

Add support for the generic mctrl gpio helper.  This will allow us to
convert several board files to use the gpiod tables to assign GPIOs to
serial ports, rather than needing to have private function callbacks.

If the generic mctrl gpio helper fails, ignore the mctrl gpios rather
than preventing the (possibly console) serial port from being created.

Acked-by: Greg Kroah-Hartman 
Acked-by: Linus Walleij 
Signed-off-by: Russell King