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

["lihuisong (C)" <lihuisong@huawei.com>]

Hi Sudeep,

On 6/13/2026 1:02 AM, 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@arm.com>
> Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>
> ---
>   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 636879ae1db7..7c9451ab4527 100644
> --- a/drivers/mailbox/pcc.c
> +++ b/drivers/mailbox/pcc.c
> @@ -447,9 +447,14 @@ static int pcc_send_data(struct mbox_chan *chan, void *data)
>   
>   static bool pcc_last_tx_done(struct mbox_chan *chan)
>   {
> +	bool ret;
>   	struct pcc_chan_info *pchan = chan->con_priv;
>   
> -	return pcc_mbox_cmd_complete_check(pchan);
> +	ret = pcc_mbox_cmd_complete_check(pchan);
> +	if (ret && !pchan->plat_irq)
> +		mbox_chan_received_data(chan, NULL);
> +
> +	return ret;
>   }
The mailbox_controller.h said that .last_tx_done() is used only if 
txdone_poll:=true && txdone_irq:=false.
How about add a verification at the begining of this function? like "if 
(chan->txdone_method != MBOX_TXDONE_BY_POLL) return false;"
And then call mbox_chan_received_data() directly if command completed.

This patch is ok to me if has above changes.
Acked-by: lihuisong@huawei.com


But pcc mbox controller can no longer work in MBOX_TXDONE_BY_ACK after 
your commit:
3349f800609e (mailbox: pcc: Set txdone_irq/txdone_poll based on PCCT flags).
This may lead to above client drivers fail to send mailbox command, like 
cppc_acpi,hisi_uncore_freq and kunpeng_hccs.
Because these client driver knows tx_done(knows_txdone: true), work on 
this mode and need to call mbox_client_txdone.
Do you have some idea for this?
>   
>   /**