kernel/linux.git/drivers/tty/serial/mcf.c, branch v6.7

serial: mcf: Use port lock wrappers

2023-09-18T09:18:12+00:00

When a serial port is used for kernel console output, then all modifications to the UART registers which are done from other contexts, e.g. getty, termios, are interference points for the kernel console. So far this has been ignored and the printk output is based on the principle of hope. The rework of the console infrastructure which aims to support threaded and atomic consoles, requires to mark sections which modify the UART registers as unsafe. This allows the atomic write function to make informed decisions and eventually to restore operational state. It also allows to prevent the regular UART code from modifying UART registers while printk output is in progress. All modifications of UART registers are guarded by the UART port lock, which provides an obvious synchronization point with the console infrastructure. To avoid adding this functionality to all UART drivers, wrap the spin_[un]lock*() invocations for uart_port::lock into helper functions which just contain the spin_[un]lock*() invocations for now. In a subsequent step these helpers will gain the console synchronization mechanisms. Converted with coccinelle. No functional change. Signed-off-by: Thomas Gleixner Signed-off-by: John Ogness Link: https://lore.kernel.org/r/20230914183831.587273-36-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman

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

serial: Embed rs485_supported to uart_port

2022-07-08T13:14:09+00:00

Embed rs485_supported to uart_port to allow serial core to tweak it as needed. Reviewed-by: Lino Sanfilippo Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20220704094515.6831-2-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: take termios_rwsem for ->rs485_config() & pass termios as param

2022-06-27T12:44:20+00:00

To be able to alter ADDRB within ->rs485_config(), take termios_rwsem before calling ->rs485_config() and pass termios. Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20220624204210.11112-5-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: mcf: Remove serial_rs485 assignment

2022-06-10T11:49:58+00:00

Serial core handles serial_rs485 assignment. Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20220606100433.13793-35-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: mcf: Fill in rs485_supported

2022-06-10T11:49:56+00:00

Add information on supported serial_rs485 features. Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20220606100433.13793-19-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: mcf: use helpers in mcf_tx_chars()

2022-01-26T13:55:14+00:00

Use uart_circ_empty() instead of open-coding it via xmit->head & tail. Use preexisting mcf_stop_tx() to avoid stop-tx code duplication. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20220124071430.14907-12-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

serial: mcf: drop low-latency workaround

2021-04-22T10:09:25+00:00

Commit 5275ad70fed3 ("tty: serial: mcf: 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/20210421095509.3024-14-johan@kernel.org Signed-off-by: Greg Kroah-Hartman