Re: [PATCH v7 2/6] serial: 8250: create lsr_save_mask

Andy Shevchenko
2022-06-15T14:02:10Z

On Wed, Jun 15, 2022 at 03:48:25PM +0300, Ilpo Järvinen wrote:
> Allow drivers to alter LSR save mask.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> ---
> drivers/tty/serial/8250/8250.h | 2 +-
> drivers/tty/serial/8250/8250_core.c | 4 ++++
> drivers/tty/serial/8250/8250_dw.c | 2 +-
> include/linux/serial_8250.h | 1 +
> 4 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
> index 0ff5688ba90c..5cc967fe3b59 100644
> --- a/drivers/tty/serial/8250/8250.h
> +++ b/drivers/tty/serial/8250/8250.h
> @@ -138,7 +138,7 @@ static inline u16 serial_lsr_in(struct uart_8250_port *up)
> u16 lsr = up->lsr_saved_flags;
>
> lsr |= serial_in(up, UART_LSR);
> - up->lsr_saved_flags = lsr & LSR_SAVE_FLAGS;
> + up->lsr_saved_flags = lsr & up->lsr_save_mask;
>
> return lsr;
> }
> diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
> index 90ddc8924811..57e86133af4f 100644
> --- a/drivers/tty/serial/8250/8250_core.c
> +++ b/drivers/tty/serial/8250/8250_core.c
> @@ -1007,6 +1007,7 @@ int serial8250_register_8250_port(const struct uart_8250_port *up)
> uart->port.rs485 = up->port.rs485;
> uart->rs485_start_tx = up->rs485_start_tx;
> uart->rs485_stop_tx = up->rs485_stop_tx;
> + uart->lsr_save_mask = up->lsr_save_mask;
> uart->dma = up->dma;
>
> /* Take tx_loadsz from fifosize if it wasn't set separately */
> @@ -1094,6 +1095,9 @@ int serial8250_register_8250_port(const struct uart_8250_port *up)
> ret = 0;
> }
>
> + if (!uart->lsr_save_mask)
> + uart->lsr_save_mask = LSR_SAVE_FLAGS; /* Use default LSR mask */
> +
> /* Initialise interrupt backoff work if required */
> if (up->overrun_backoff_time_ms > 0) {
> uart->overrun_backoff_time_ms =
> diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
> index 4cc69bb612ab..167a691c7b19 100644
> --- a/drivers/tty/serial/8250/8250_dw.c
> +++ b/drivers/tty/serial/8250/8250_dw.c
> @@ -129,7 +129,7 @@ static void dw8250_tx_wait_empty(struct uart_port *p)
>
> while (tries--) {
> lsr = readb (p->membase + (UART_LSR << p->regshift));
> - up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
> + up->lsr_saved_flags |= lsr & up->lsr_save_mask;
>
> if (lsr & UART_LSR_TEMT)
> break;
> diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
> index 4565f25ba9a2..8c7b793aa4d7 100644
> --- a/include/linux/serial_8250.h
> +++ b/include/linux/serial_8250.h
> @@ -120,6 +120,7 @@ struct uart_8250_port {
> */
> #define LSR_SAVE_FLAGS UART_LSR_BRK_ERROR_BITS
> u16 lsr_saved_flags;
> + u16 lsr_save_mask;
> #define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA
> unsigned char msr_saved_flags;
>
> --
> 2.30.2
>

--
With Best Regards,
Andy Shevchenko