mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity

serial: Do not hold the port lock when setting rx-during-tx GPIO 

Both the imx and stm32 driver set the rx-during-tx GPIO in rs485_config().
Since this function is called with the port lock held, this can be a
problem in case that setting the GPIO line can sleep (e.g. if a GPIO
expander is used which is connected via SPI or I2C).

Avoid this issue by moving the GPIO setting outside of the port lock into
the serial core and thus making it a generic feature.

Also with commit c54d485436 ("serial: stm32: Add support for rs485
RX_DURING_TX output GPIO") the SER_RS485_RX_DURING_TX flag is only set if a
rx-during-tx GPIO is _not_ available, which is wrong. Fix this, too.

Furthermore reset old GPIO settings in case that changing the RS485
configuration failed.

Fixes: c54d485436 ("serial: stm32: Add support for rs485 RX_DURING_TX output GPIO")
Fixes: ca530cfa96 ("serial: imx: Add support for RS485 RX_DURING_TX output GPIO")
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc:  <stable@vger.kernel.org>
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Link: https://lore.kernel.org/r/20240103061818.564-2-l.sanfilippo@kunbus.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Lino Sanfilippo 2024-01-03 07:18:12 +01:00 committed by Greg Kroah-Hartman
parent da680c045f
commit 07c30ea586
3 changed files with 26 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/tty/serial/imx.c
View File

@ -1948,10 +1948,6 @@ static int imx_uart_rs485_config(struct uart_port *port, struct ktermios *termio
rs485conf->flags & SER_RS485_RX_DURING_TX)
imx_uart_start_rx(port);
if (port->rs485_rx_during_tx_gpio)
gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
!!(rs485conf->flags & SER_RS485_RX_DURING_TX));
return 0;
}

26
drivers/tty/serial/serial_core.c
View File

@ -1407,6 +1407,16 @@ static void uart_set_rs485_termination(struct uart_port *port,
!!(rs485->flags & SER_RS485_TERMINATE_BUS));
}
static void uart_set_rs485_rx_during_tx(struct uart_port *port,
const struct serial_rs485 *rs485)
{
if (!(rs485->flags & SER_RS485_ENABLED))
return;
gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
!!(rs485->flags & SER_RS485_RX_DURING_TX));
}
static int uart_rs485_config(struct uart_port *port)
{
struct serial_rs485 *rs485 = &port->rs485;
@ -1418,12 +1428,17 @@ static int uart_rs485_config(struct uart_port *port)
uart_sanitize_serial_rs485(port, rs485);
uart_set_rs485_termination(port, rs485);
uart_set_rs485_rx_during_tx(port, rs485);
uart_port_lock_irqsave(port, &flags);
ret = port->rs485_config(port, NULL, rs485);
uart_port_unlock_irqrestore(port, flags);
if (ret)
if (ret) {
memset(rs485, 0, sizeof(*rs485));
/* unset GPIOs */
gpiod_set_value_cansleep(port->rs485_term_gpio, 0);
gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio, 0);
}
return ret;
}
@ -1462,6 +1477,7 @@ static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
return ret;
uart_sanitize_serial_rs485(port, &rs485);
uart_set_rs485_termination(port, &rs485);
uart_set_rs485_rx_during_tx(port, &rs485);
uart_port_lock_irqsave(port, &flags);
ret = port->rs485_config(port, &tty->termios, &rs485);
@ -1473,8 +1489,14 @@ static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
port->ops->set_mctrl(port, port->mctrl);
}
uart_port_unlock_irqrestore(port, flags);
if (ret)
if (ret) {
/* restore old GPIO settings */
gpiod_set_value_cansleep(port->rs485_term_gpio,
!!(port->rs485.flags & SER_RS485_TERMINATE_BUS));
gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
!!(port->rs485.flags & SER_RS485_RX_DURING_TX));
return ret;
}
if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
return -EFAULT;

8
drivers/tty/serial/stm32-usart.c
View File

@ -226,12 +226,6 @@ static int stm32_usart_config_rs485(struct uart_port *port, struct ktermios *ter
stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
if (port->rs485_rx_during_tx_gpio)
gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
!!(rs485conf->flags & SER_RS485_RX_DURING_TX));
else
rs485conf->flags |= SER_RS485_RX_DURING_TX;
if (rs485conf->flags & SER_RS485_ENABLED) {
cr1 = readl_relaxed(port->membase + ofs->cr1);
cr3 = readl_relaxed(port->membase + ofs->cr3);
@ -256,6 +250,8 @@ static int stm32_usart_config_rs485(struct uart_port *port, struct ktermios *ter
writel_relaxed(cr3, port->membase + ofs->cr3);
writel_relaxed(cr1, port->membase + ofs->cr1);
rs485conf->flags |= SER_RS485_RX_DURING_TX;
} else {
stm32_usart_clr_bits(port, ofs->cr3,
USART_CR3_DEM | USART_CR3_DEP);