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mailbox: pcc: Clear any pending responder interrupts before enabling it

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Some platforms may leave a responder interrupt pending from earlier
transactions. 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 <sudeep.holla@arm.com>
Tested-by: Adam Young <admiyo@os.amperecomputing.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
This commit is contained in:
Sudeep Holla 2025-10-16 20:08:20 +01:00 • committed by Jassi Brar
parent 9f3bbbb72a
commit c2b69f71ff
1 changed files with 6 additions and 0 deletions
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6
drivers/mailbox/pcc.c
View file

@ -467,6 +467,12 @@ 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;