On Mon, 7 Nov 2022 at 17:15, Gabriel Somlo <gsomlo@xxxxxxxxx> wrote:
>
> Move the character-receive (RX) loop to its own dedicated function,
> and (for now) call that from the poll timer, liteuart_timer().
>
> This is in preparation for adding IRQ support to the receive path.
>
> Signed-off-by: Gabriel Somlo <gsomlo@xxxxxxxxx>
> ---
> drivers/tty/serial/liteuart.c | 25 +++++++++++++++----------
> 1 file changed, 15 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c
> index 4b9cca249828..90a29ed79bff 100644
> --- a/drivers/tty/serial/liteuart.c
> +++ b/drivers/tty/serial/liteuart.c
> @@ -69,29 +69,34 @@ static struct uart_driver liteuart_driver = {
> #endif
> };
>
> -static void liteuart_timer(struct timer_list *t)
> +static void liteuart_rx_chars(struct uart_port *port)
> {
> - struct liteuart_port *uart = from_timer(uart, t, timer);
> - struct uart_port *port = &uart->port;
> unsigned char __iomem *membase = port->membase;
> - unsigned int flg = TTY_NORMAL;
> - int ch;
> - unsigned long status;
> + unsigned int status;
> + unsigned char ch;
u32, u8, void __iomem * would be better kernel types to use here.
You've also changed ch from a signed 32 to an unsigned 8.
>
> while ((status = !litex_read8(membase + OFF_RXEMPTY)) == 1) {
> ch = litex_read8(membase + OFF_RXTX);
> port->icount.rx++;
>
> /* necessary for RXEMPTY to refresh its value */
> - litex_write8(membase + OFF_EV_PENDING, EV_TX | EV_RX);
> + litex_write8(membase + OFF_EV_PENDING, EV_RX);
You're no longer clearing EV_TX, but don't mention why (I understand
why with the context of the other changes, so perhaps add something to
this commit message).
>
> /* no overflow bits in status */
> if (!(uart_handle_sysrq_char(port, ch)))
> - uart_insert_char(port, status, 0, ch, flg);
> -
> - tty_flip_buffer_push(&port->state->port);
> + uart_insert_char(port, status, 0, ch, TTY_NORMAL);
> }
>
> + tty_flip_buffer_push(&port->state->port);
> +}
> +
> +static void liteuart_timer(struct timer_list *t)
> +{
> + struct liteuart_port *uart = from_timer(uart, t, timer);
> + struct uart_port *port = &uart->port;
> +
> + liteuart_rx_chars(port);
> +
> mod_timer(&uart->timer, jiffies + uart_poll_timeout(port));
> }
>
> --
> 2.37.3
>
