On Monday 05 September 2022 19:24:17 Michael Nazzareno Trimarchi wrote: > Hi > > Il lun 5 set 2022, 11:32 Pali Rohár <p...@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?
Yes, for tty devices it is drain. But for C stdio.h it is (f)flush. Hence I used more generic name flush() as it is not only for serial devices, but for any U-Boot stdio device. E.g. sandbox os use real fflush function. But feel free to choose any other name of function. I do not care a much about it. > Michael > > > > Signed-off-by: Pali Rohár <p...@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 > > > >