On Tue, 6 Feb 2024 16:42:07 -0500
Hugo Villeneuve <hugo@xxxxxxxxxxx> wrote:
> From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
>
> Before, sc16is7xx_lines was checked for a free (zero) bit first, and then
> later it was set only if UART port registration succeeded.
>
> Now that sc16is7xx_lines is shared for the I2C and SPI drivers, make sure
> it is reserved and modified atomically, and use a new variable to hold the
> status of UART port regisration.
>
> Remove need to check for previous port registration in sc16is7xx_remove(),
> because if sc16is7xx_probe() succeeded, we are guaranteed to have
> successfully registered both ports.
>
> Signed-off-by: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
> ---
> drivers/tty/serial/sc16is7xx.c | 19 ++++++++++++-------
> 1 file changed, 12 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
> index 5b53c88b7133..5073ebfc45bf 100644
> --- a/drivers/tty/serial/sc16is7xx.c
> +++ b/drivers/tty/serial/sc16is7xx.c
> @@ -1468,6 +1468,7 @@ int sc16is7xx_probe(struct device *dev, const struct sc16is7xx_devtype *devtype,
> u32 uartclk = 0;
> int i, ret;
> struct sc16is7xx_port *s;
> + bool port_registered[SC16IS7XX_MAX_PORTS];
>
> for (i = 0; i < devtype->nr_uart; i++)
> if (IS_ERR(regmaps[i]))
> @@ -1533,8 +1534,10 @@ int sc16is7xx_probe(struct device *dev, const struct sc16is7xx_devtype *devtype,
> SC16IS7XX_IOCONTROL_SRESET_BIT);
>
> for (i = 0; i < devtype->nr_uart; ++i) {
> - s->p[i].port.line = find_first_zero_bit(sc16is7xx_lines,
> - SC16IS7XX_MAX_DEVS);
> + port_registered[i] = false;
I just realised that this will not work. All port_registered[]
members need to be initialized before entering the loop.
I will add this (for V2) before the loop:
memset(port_registered, 0, sizeof(port_registered));
Hugo Villeneuve
> +
> + s->p[i].port.line = find_and_set_bit(sc16is7xx_lines,
> + SC16IS7XX_MAX_DEVS);
> if (s->p[i].port.line >= SC16IS7XX_MAX_DEVS) {
> ret = -ERANGE;
> goto out_ports;
> @@ -1584,7 +1587,7 @@ int sc16is7xx_probe(struct device *dev, const struct sc16is7xx_devtype *devtype,
> if (ret)
> goto out_ports;
>
> - set_bit(s->p[i].port.line, sc16is7xx_lines);
> + port_registered[i] = true;
>
> /* Enable EFR */
> sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_LCR_REG,
> @@ -1642,9 +1645,11 @@ int sc16is7xx_probe(struct device *dev, const struct sc16is7xx_devtype *devtype,
> #endif
>
> out_ports:
> - for (i = 0; i < devtype->nr_uart; i++)
> - if (test_and_clear_bit(s->p[i].port.line, sc16is7xx_lines))
> + for (i = 0; i < devtype->nr_uart; i++) {
> + clear_bit(s->p[i].port.line, sc16is7xx_lines);
> + if (port_registered[i])
> uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
> + }
>
> kthread_stop(s->kworker_task);
>
> @@ -1667,8 +1672,8 @@ void sc16is7xx_remove(struct device *dev)
>
> for (i = 0; i < s->devtype->nr_uart; i++) {
> kthread_cancel_delayed_work_sync(&s->p[i].ms_work);
> - if (test_and_clear_bit(s->p[i].port.line, sc16is7xx_lines))
> - uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
> + clear_bit(s->p[i].port.line, sc16is7xx_lines);
> + uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
> sc16is7xx_power(&s->p[i].port, 0);
> }
>
> --
> 2.39.2
>
>
