user/sven/linux.git/include/linux/serial_core.h, branch v5.8

serial: core: drop redundant sysrq checks

2020-06-27T14:16:37Z

The sysrq timestamp will never be set unless port->has_sysrq is set (see uart_handle_break()) so drop the redundant checks that were added by commit 1997e9dfdc84 ("serial_core: Un-ifdef sysrq SUPPORT_SYSRQ"). Signed-off-by: Johan Hovold Reviewed-by: Andy Shevchenko Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com> Link: https://lore.kernel.org/r/20200610152232.16925-4-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

serial: core: fix sysrq overhead regression

2020-06-27T14:16:37Z

Commit 8e20fc391711 ("serial_core: Move sysrq functions from header file") converted the inline sysrq helpers to exported functions which are now called for every received character, interrupt and break signal also on systems without CONFIG_MAGIC_SYSRQ_SERIAL instead of being optimised away by the compiler. Inlining these helpers again also avoids the function call overhead when CONFIG_MAGIC_SYSRQ_SERIAL is enabled (e.g. when the port is not used as a console). Fixes: 8e20fc391711 ("serial_core: Move sysrq functions from header file") Cc: Dmitry Safonov <0x7f454c46@gmail.com> Signed-off-by: Johan Hovold Cc: stable Reviewed-by: Andy Shevchenko Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com> Link: https://lore.kernel.org/r/20200610152232.16925-3-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

Revert "serial: core: Refactor uart_unlock_and_check_sysrq()"

2020-06-27T14:16:37Z

This reverts commit da9a5aa3402db0ff3b57216d8dbf2478e1046cae. In order to ease backporting a fix for a sysrq regression, revert this rewrite which was since added on top. The other sysrq helpers now bail out early when sysrq is not enabled; it's better to keep that pattern here as well. Note that the __releases() attribute won't be needed after the follow-on fix either. Fixes: da9a5aa3402d ("serial: core: Refactor uart_unlock_and_check_sysrq()") Cc: stable Signed-off-by: Johan Hovold Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200610152232.16925-2-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

serial: 8250: Support rs485 bus termination GPIO

2020-05-29T10:42:54Z

Commit e8759ad17d41 ("serial: uapi: Add support for bus termination") introduced the ability to enable rs485 bus termination from user space. So far the feature is only used by a single driver, 8250_exar.c, using a hardcoded GPIO pin specific to Siemens IOT2040 products. Provide for a more generic solution by allowing specification of an rs485 bus termination GPIO pin in the device tree: Amend the serial core to retrieve the GPIO from the device tree (or ACPI table) and amend the default ->rs485_config() callback for 8250 drivers to change the GPIO on request from user space. Perhaps 8250_exar.c can be converted to the generic approach in a follow-up patch. Signed-off-by: Lukas Wunner Reviewed-by: Andy Shevchenko Cc: Jan Kiszka Link: https://lore.kernel.org/r/94c6c800d1ca9fa04766dd1d43a8272c5ad4bedd.1589811297.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman

serial: Allow uart_get_rs485_mode() to return errno

2020-05-15T12:47:05Z

We're about to amend uart_get_rs485_mode() to support a GPIO pin for rs485 bus termination. Retrieving the GPIO descriptor may fail, so allow uart_get_rs485_mode() to return an errno and change all callers to check for failure. The GPIO descriptor is going to be stored in struct uart_port. Pass that struct to uart_get_rs485_mode() in lieu of a struct device and struct serial_rs485, both of which are directly accessible from struct uart_port. A few drivers call uart_get_rs485_mode() before setting the struct device pointer in struct uart_port. Shuffle those calls around where necessary. [Heiko Stuebner did the ar933x_uart.c portion, hence his Signed-off-by.] Signed-off-by: Heiko Stuebner Signed-off-by: Lukas Wunner Link: https://lore.kernel.org/r/271e814af4b0db3bffbbb74abf2b46b75add4516.1589285873.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman

serial: core: Refactor uart_unlock_and_check_sysrq()

2020-03-12T16:16:42Z

Refactor uart_unlock_and_check_sysrq() to: - explicitly show that we release a port lock which makes static analyzers happy: CHECK drivers/tty/serial/serial_core.c .../serial_core.c:3290:17: warning: context imbalance in 'uart_unlock_and_check_sysrq' - unexpected unlock - use flags instead of irqflags to avoid confusion with IRQ flags - provide one return point - be more compact Signed-off-by: Andy Shevchenko Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com> Link: https://lore.kernel.org/r/20200310174337.74109-4-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial/sysrq: Add MAGIC_SYSRQ_SERIAL_SEQUENCE

2020-03-07T08:52:02Z

Many embedded boards have a disconnected TTL level serial which can generate some garbage that can lead to spurious false sysrq detects. Currently, sysrq can be either completely disabled for serial console or always disabled (with CONFIG_MAGIC_SYSRQ_SERIAL), since commit 732dbf3a6104 ("serial: do not accept sysrq characters via serial port") At Arista, we have such boards that can generate BREAK and random garbage. While disabling sysrq for serial console would solve the problem with spurious false sysrq triggers, it's also desirable to have a way to enable sysrq back. As a measure of balance between on and off options, add MAGIC_SYSRQ_SERIAL_SEQUENCE which is a string sequence that can enable sysrq if it follows BREAK on a serial line. The longer the string - the less likely it may be in the garbage. Having the way to enable sysrq was beneficial to debug lockups with a manual investigation in field and on the other side preventing false sysrq detections. Based-on-patch-by: Vasiliy Khoruzhick Signed-off-by: Dmitry Safonov Link: https://lore.kernel.org/r/20200302175135.269397-3-dima@arista.com Signed-off-by: Greg Kroah-Hartman

serial_core: Remove unused member in uart_port

2020-01-15T12:39:14Z

It should remove the align-padding before @name. [yes, there's a "hole" in the structure now, but that's fine, no one cares. If they do care, the whole thing should be restructured using pahole to find a better ordering. Removing this field is good as some drivers have been known to abuse it for other things when they shouldn't have been doing that. -- gregkh] Signed-off-by: Dmitry Safonov Link: https://lore.kernel.org/r/20200114171912.261787-4-dima@arista.com Signed-off-by: Greg Kroah-Hartman

serial_core: Move sysrq functions from header file

2020-01-10T16:48:02Z

It's not worth to have them in every serial driver and I'm about to add another helper function. Signed-off-by: Dmitry Safonov Link: https://lore.kernel.org/r/20200109215444.95995-2-dima@arista.com Signed-off-by: Greg Kroah-Hartman

serial_core: Remove SUPPORT_SYSRQ ifdeffery

2019-12-18T14:05:11Z

No one defines it anymore. Signed-off-by: Dmitry Safonov Link: https://lore.kernel.org/r/20191213000657.931618-55-dima@arista.com Signed-off-by: Greg Kroah-Hartman