Re: [PATCH v2 6/7] serial: liteuart: separate RX loop from poll timer

[Ilpo Järvinen]

On Wed, 9 Nov 2022, Gabriel Somlo 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 047d5ad32e13..aa7052280197 100644
> --- a/drivers/tty/serial/liteuart.c
> +++ b/drivers/tty/serial/liteuart.c
> @@ -67,29 +67,34 @@ 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;
>  
>  	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);
>  
>  		/* 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);

This change is doing extra stuff besides moving rx to a dedicated 
function.

I see no reason why those other changes couldn't be put into an entirely 
separate patch. Also, please described those changes properly in the 
commit message (answer the why? question).

-- 
 i.

> +}
> +
> +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));
>  }
>  
>