Tested-by: Adam Young <admiyo@os.amperecomputing.com>
On 10/16/25 15:08, Sudeep Holla wrote:
> The PCC controller currently enables txdone via IRQ if the PCCT exposes
> platform capability to generate command completion interrupt, but it
> leaves txdone_poll unchanged. Make the behaviour explicit:
>
> - If ACPI_PCCT_DOORBELL is present, use txdone_irq and disable polling.
> - Otherwise, disable txdone_irq and fall back to txdone_poll.
>
> Configure the PCC mailbox to use interrupt-based completion for PCC types
> that signal completion via IRQ using TXDONE_BY_IRQ, and fall back to
> polling for others using TXDONE_BY_POLL.
>
> This ensures the PCC driver uses the appropriate completion mechanism
> according to the PCCT table definition and makes the completion mode
> unambiguous avoiding mixed signalling when the platform lacks a doorbell
> flag set.
>
> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> ---
> drivers/mailbox/pcc.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
> index 2b690c268cf0..327e022973db 100644
> --- a/drivers/mailbox/pcc.c
> +++ b/drivers/mailbox/pcc.c
> @@ -791,8 +791,13 @@ static int pcc_mbox_probe(struct platform_device *pdev)
> (unsigned long) pcct_tbl + sizeof(struct acpi_table_pcct));
>
> acpi_pcct_tbl = (struct acpi_table_pcct *) pcct_tbl;
> - if (acpi_pcct_tbl->flags & ACPI_PCCT_DOORBELL)
> + if (acpi_pcct_tbl->flags & ACPI_PCCT_DOORBELL) {
> pcc_mbox_ctrl->txdone_irq = true;
> + pcc_mbox_ctrl->txdone_poll = false;
> + } else {
> + pcc_mbox_ctrl->txdone_irq = false;
> + pcc_mbox_ctrl->txdone_poll = true;
> + }
>
> for (i = 0; i < count; i++) {
> struct pcc_chan_info *pchan = chan_info + i;
>