diff options
| author | Lino Sanfilippo <l.sanfilippo@kunbus.com> | 2024-01-03 09:18:14 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-01-04 18:26:10 +0300 |
| commit | 4afeced55baa391490b61ed9164867e2927353ed (patch) | |
| tree | c38e5fe32a7e42c68b5293c106fd0783e22f42eb /drivers/tty | |
| parent | 1a33e33ca0e80d485458410f149265cdc0178cfa (diff) | |
| download | linux-4afeced55baa391490b61ed9164867e2927353ed.tar.xz | |
serial: core: fix sanitizing check for RTS settings
Among other things uart_sanitize_serial_rs485() tests the sanity of the RTS
settings in a RS485 configuration that has been passed by userspace.
If RTS-on-send and RTS-after-send are both set or unset the configuration
is adjusted and RTS-after-send is disabled and RTS-on-send enabled.
This however makes only sense if both RTS modes are actually supported by
the driver.
With commit be2e2cb1d281 ("serial: Sanitize rs485_struct") the code does
take the driver support into account but only checks if one of both RTS
modes are supported. This may lead to the errorneous result of RTS-on-send
being set even if only RTS-after-send is supported.
Fix this by changing the implemented logic: First clear all unsupported
flags in the RS485 configuration, then adjust an invalid RTS setting by
taking into account which RTS mode is supported.
Cc: <stable@vger.kernel.org>
Fixes: be2e2cb1d281 ("serial: Sanitize rs485_struct")
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Link: https://lore.kernel.org/r/20240103061818.564-4-l.sanfilippo@kunbus.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/serial_core.c | 28 |
1 files changed, 18 insertions, 10 deletions
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 850f24cc53e5..cd8c3a70455e 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1376,19 +1376,27 @@ static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs4 return; } + rs485->flags &= supported_flags; + /* Pick sane settings if the user hasn't */ - if ((supported_flags & (SER_RS485_RTS_ON_SEND|SER_RS485_RTS_AFTER_SEND)) && - !(rs485->flags & SER_RS485_RTS_ON_SEND) == + if (!(rs485->flags & SER_RS485_RTS_ON_SEND) == !(rs485->flags & SER_RS485_RTS_AFTER_SEND)) { - dev_warn_ratelimited(port->dev, - "%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n", - port->name, port->line); - rs485->flags |= SER_RS485_RTS_ON_SEND; - rs485->flags &= ~SER_RS485_RTS_AFTER_SEND; - supported_flags |= SER_RS485_RTS_ON_SEND|SER_RS485_RTS_AFTER_SEND; - } + if (supported_flags & SER_RS485_RTS_ON_SEND) { + rs485->flags |= SER_RS485_RTS_ON_SEND; + rs485->flags &= ~SER_RS485_RTS_AFTER_SEND; - rs485->flags &= supported_flags; + dev_warn_ratelimited(port->dev, + "%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n", + port->name, port->line); + } else { + rs485->flags |= SER_RS485_RTS_AFTER_SEND; + rs485->flags &= ~SER_RS485_RTS_ON_SEND; + + dev_warn_ratelimited(port->dev, + "%s (%d): invalid RTS setting, using RTS_AFTER_SEND instead\n", + port->name, port->line); + } + } uart_sanitize_serial_rs485_delays(port, rs485); |