Re: [Qemu-devel] [Qemu-trivial] [PATCH] cadence_uart: Check if receiver timeout counter is disabled

["Edgar E. Iglesias" <edgar.iglesias@gmail.com>]

On Thu, Dec 08, 2016 at 08:50:40AM +0100, Laurent Vivier wrote:
> I CC: Xilinx Zynq Maintainers.
> 
> Laurent

Thanks

> 
> On 07/12/2016 22:12, Andrew Gacek wrote:
> > When register Rcvr_timeout_reg0 (R_RTOR in cadence_uart.c) is set to
> > 0, the receiver timeout counter should be disabled. See page 1801 of
> > "Zynq-7000 AP SoC Technical Reference Manual". This commit adds a
> > such a check before setting the receive timeout interrupt.

We could also try to disable the timer when rtor is zero but I think
that exposes a bunch of corner cases that would complicate the model a bit.
So IMO, this patch is good.


> > Signed-off-by: Andrew Gacek <andrew.gacek@gmail.com>
> > ---
> >  hw/char/cadence_uart.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/hw/char/cadence_uart.c b/hw/char/cadence_uart.c
> > index 0215d65..54194b1 100644
> > --- a/hw/char/cadence_uart.c
> > +++ b/hw/char/cadence_uart.c
> > @@ -138,7 +138,9 @@ static void fifo_trigger_update(void *opaque)
> >  {
> >      CadenceUARTState *s = opaque;
> > 
> > -    s->r[R_CISR] |= UART_INTR_TIMEOUT;
> > +    if (s->r[R_RTOR]) {
> > +        s->r[R_CISR] |= UART_INTR_TIMEOUT;
> > +    }
> > 
> >      uart_update_status(s);

Since you are not modifying the IRQ state when the timeout is disabled, you can avoid calling uart_update_status too (because it will only end up recomputing the same state).

With that fix:
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>

Best regards,
Edgar