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If a PCC responder channel has a pending interrupt when > the controller starts up, enabling the IRQ line without first clearing > the condition can lead to a spurious interrupt which could disrupt other > transmissions if the IRQ is shared. > > Explicitly clear any pending responder interrupt before enabling the IRQ > to ensure a clean start. Acknowledge the responder channel via > pcc_chan_acknowledge() in startup before requesting/enablement of the > IRQ. This ensures a clean baseline for the first transfer/receiption > of the notification/response. > > Signed-off-by: Sudeep Holla > --- > drivers/mailbox/pcc.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c > index 2829ec51b47f..418007020439 100644 > --- a/drivers/mailbox/pcc.c > +++ b/drivers/mailbox/pcc.c > @@ -468,6 +468,12 @@ static int pcc_startup(struct mbox_chan *chan) > unsigned long irqflags; > int rc; > > + /* > + * Clear and acknowledge any pending interrupts on responder channel > + * before enabling the interrupt > + */ > + pcc_chan_acknowledge(pchan); > + > if (pchan->plat_irq > 0) { > irqflags = pcc_chan_plat_irq_can_be_shared(pchan) ? > IRQF_SHARED | IRQF_ONESHOT : 0; >