diff mbox series

[v5,10/14] serial: liteuart: separate rx loop from poll timer

Message ID 20221118145512.509950-11-gsomlo@gmail.com
State New
Headers
Series serial: liteuart: add IRQ support |

Commit Message

Gabriel L. Somlo Nov. 18, 2022, 2:55 p.m. UTC 
  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@gmail.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 drivers/tty/serial/liteuart.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

Comments

Geert Uytterhoeven Nov. 21, 2022, 10:16 a.m. UTC | #1 
Hi Gabriel,

On Fri, Nov 18, 2022 at 3:57 PM Gabriel Somlo <gsomlo@gmail.com> 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@gmail.com>
> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

Thanks for your patch!

Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>

> --- 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...


>  {
> -       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@linux-m68k.org

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
Gabriel L. Somlo Nov. 21, 2022, 4:44 p.m. UTC | #2 
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@gmail.com> 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@gmail.com>
> > Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> 
> Thanks for your patch!
> 
> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
> 
> > --- 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@linux-m68k.org
> 
> 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
diff mbox series

Patch

diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c
index 42ac9aee050a..76f8a09b82cd 100644
--- 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)
 {
-	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));
 }