[PATCH v3 3/6] serial: Implement flush callback

[Michael Nazzareno Trimarchi]

Hi

Il lun 5 set 2022, 11:32 Pali Rohár <pali at kernel.org> ha scritto:

> UART drivers have putc/puts functions which just put characters into HW
> transmit queue and do not wait until all data are transmitted.
>
> Implement flush callback via serial driver's pending(false) callback which
> waits until HW transmit all characters from the queue.
>

This is a drain if you want to wait. Is not the right terminology?

Michael


> Signed-off-by: Pali Rohár <pali at kernel.org>
> ---
>  drivers/serial/serial-uclass.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
>
> diff --git a/drivers/serial/serial-uclass.c
> b/drivers/serial/serial-uclass.c
> index 30650e37b0d7..be6502f3d24c 100644
> --- a/drivers/serial/serial-uclass.c
> +++ b/drivers/serial/serial-uclass.c
> @@ -238,6 +238,18 @@ static void _serial_puts(struct udevice *dev, const
> char *str)
>         } while (*str);
>  }
>
> +#ifdef CONFIG_CONSOLE_FLUSH_SUPPORT
> +static void _serial_flush(struct udevice *dev)
> +{
> +       struct dm_serial_ops *ops = serial_get_ops(dev);
> +
> +       if (!ops->pending)
> +               return;
> +       while (ops->pending(dev, false) > 0)
> +               ;
> +}
> +#endif
> +
>  static int __serial_getc(struct udevice *dev)
>  {
>         struct dm_serial_ops *ops = serial_get_ops(dev);
> @@ -398,6 +410,13 @@ static void serial_stub_puts(struct stdio_dev *sdev,
> const char *str)
>         _serial_puts(sdev->priv, str);
>  }
>
> +#ifdef CONFIG_CONSOLE_FLUSH_SUPPORT
> +static void serial_stub_flush(struct stdio_dev *sdev)
> +{
> +       _serial_flush(sdev->priv);
> +}
> +#endif
> +
>  static int serial_stub_getc(struct stdio_dev *sdev)
>  {
>         return _serial_getc(sdev->priv);
> @@ -520,6 +539,7 @@ static int serial_post_probe(struct udevice *dev)
>         sdev.priv = dev;
>         sdev.putc = serial_stub_putc;
>         sdev.puts = serial_stub_puts;
> +       STDIO_DEV_ASSIGN_FLUSH(&sdev, serial_stub_flush);
>         sdev.getc = serial_stub_getc;
>         sdev.tstc = serial_stub_tstc;
>
> --
> 2.20.1
>
>