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Re: [Qemu-trivial] [PATCH] cadence_uart: Check if receiver timeout count
From: |
Edgar E. Iglesias |
Subject: |
Re: [Qemu-trivial] [PATCH] cadence_uart: Check if receiver timeout counter is disabled |
Date: |
Thu, 8 Dec 2016 11:42:52 +0100 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
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 <address@hidden>
> > ---
> > 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 <address@hidden>
Best regards,
Edgar