Re: [PATCH 1/3] mailbox: pcc: Notify clients on polled completion

[Sudeep Holla]

On Thu, Jul 23, 2026 at 12:03:45PM -0400, Adam Young wrote:
> 
> On 7/17/26 03:56, Sudeep Holla wrote:
> > PCC channels without a platform interrupt rely on the mailbox
> > polling path to detect command completion.
> > 
> > That path currently only reports transmit completion to the mailbox
> > core, so clients that wait for their receive callback do not get
> > notified when the command completes.
> > 
> > Call mbox_chan_received_data() when polling observes completion on a
> > channel without a platform IRQ, matching the interrupt-driven
> > completion path.
> > 
> > Reported-by: Cristian Marussi <cristian.marussi@xxxxxxx>
> > Acked-by: Huisong Li <lihuisong@xxxxxxxxxx>
> > Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxxxxx>
> > ---
> >   drivers/mailbox/pcc.c | 10 +++++++++-
> >   1 file changed, 9 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
> > index 636879ae1db7..d96b8b54e77e 100644
> > --- a/drivers/mailbox/pcc.c
> > +++ b/drivers/mailbox/pcc.c
> > @@ -449,7 +449,15 @@ static bool pcc_last_tx_done(struct mbox_chan *chan)
> >   {
> >   	struct pcc_chan_info *pchan = chan->con_priv;
> > -	return pcc_mbox_cmd_complete_check(pchan);
> > +	if (!(chan->txdone_method & MBOX_TXDONE_BY_POLL))
> > +		return false;
> > +
> > +	if (!pcc_mbox_cmd_complete_check(pchan))
> > +		return false;
> > +
> > +	mbox_chan_received_data(chan, NULL);
> > +
> > +	return true;
> >   }
> >   /**
> 
> My code doesn't poll, so I cannot really claim to have tested it, but it
> does not break the existing IRQ based driver mechanism.
> 

Thanks for testing IRQ mode.

> I can claim to have read through the code and confirm that it is comparable
> to what happens on the IRQ case:   It clears the cmd_complete field and
> calls mbox_chan_received_data.

Thanks for taking a look and reviewing it.

> However, it does not clear pchan->chan_in_use
> = false; (Which should now be a WRITE_ONCE) and I would like to confirm that
> is not an oversight before providing a reviewed-by tag.
> 

IIRC I think we set the flag only when irq > 0, no ?

-- 
Regards,
Sudeep