On Mon, Nov 21, 2022 at 11:16:14AM +0100, Geert Uytterhoeven wrote:
> Hi Gabriel,
>
> On Fri, Nov 18, 2022 at 3:57 PM Gabriel Somlo <gsomlo@xxxxxxxxx> wrote:
> > Convert the rx loop into its own dedicated function, and (for now)
> > call it from the poll timer. This is in preparation for adding irq
> > support to the receive path.
> >
> > Signed-off-by: Gabriel Somlo <gsomlo@xxxxxxxxx>
> > Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
>
> Thanks for your patch!
>
> Reviewed-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
>
> > --- a/drivers/tty/serial/liteuart.c
> > +++ b/drivers/tty/serial/liteuart.c
> > @@ -68,10 +68,8 @@ static struct uart_driver liteuart_driver = {
> > #endif
> > };
> >
> > -static void liteuart_timer(struct timer_list *t)
> > +static void liteuart_rx_chars(struct uart_port *port)
>
> So first you spin this off into a separate function, so it can be
> called from both the interrupt and polling paths.
> Later, in "[PATCH v5 12/14] serial: liteuart: add IRQ support for the
> RX path", you remove the call from the polling path...
That's right -- the polling path now calls the IRQ handler,
which, in turn, calls `liteuart_rx_chars()` (and later `*_tx_chars()`
as well).
The polling timer becomes just an alternative way to invoke the irq
handler, giving it a chance to take care of any pending transfers in
either/both directions.
Thanks,
--Gabriel
> > {
> > - struct liteuart_port *uart = from_timer(uart, t, timer);
> > - struct uart_port *port = &uart->port;
> > unsigned char __iomem *membase = port->membase;
> > unsigned int status, ch;
> >
> > @@ -88,6 +86,14 @@ static void liteuart_timer(struct timer_list *t)
> > }
> >
> > 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));
> > }
>
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
> -- Linus Torvalds
