Re: [PATCH v2 08/13] mailbox: pcc: Refactor and simplify check_and_ack()

lihuisong (C)
2025-03-11T11:47:45Z

在 2025/3/6 0:38, Sudeep Holla 写道:
> The existing check_and_ack() function had unnecessary complexity. The
> logic could be streamlined to improve code readability and maintainability.
>
> The command update register needs to be updated in order to acknowledge
> the platform notification through type 4 channel. So it can be done
> unconditionally. Currently it is complicated just to make use of
> pcc_send_data() which also executes the same updation.
>
> In order to simplify, let us just ring the doorbell directly from
> check_and_ack() instead of calling into pcc_send_data(). While at it,
> rename it into pcc_chan_check_and_ack() to maintain consistency in the
> driver.
LGTM except for some trivial,
Acked-by: Huisong Li <lihuisong@huawei.com>
>
> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> ---
> drivers/mailbox/pcc.c | 37 +++++++++++++------------------------
> 1 file changed, 13 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
> index b3d133170aac7f8acfd1999564c69b7fe4f6d582..90d6f5e24df7e796f8c29705808eb6df2806c1f2 100644
> --- a/drivers/mailbox/pcc.c
> +++ b/drivers/mailbox/pcc.c
> @@ -117,8 +117,6 @@ struct pcc_chan_info {
> static struct pcc_chan_info *chan_info;
> static int pcc_chan_count;
>
> -static int pcc_send_data(struct mbox_chan *chan, void *data);
> -
> /*
> * PCC can be used with perf critical drivers such as CPPC
> * So it makes sense to locally cache the virtual address and
> @@ -288,33 +286,24 @@ static int pcc_mbox_error_check_and_clear(struct pcc_chan_info *pchan)
> return 0;
> }
>
> -static void check_and_ack(struct pcc_chan_info *pchan, struct mbox_chan *chan)
> +static void pcc_chan_check_and_ack(struct pcc_chan_info *pchan)
How about use pcc_chan_ack?
> {
> - struct acpi_pcct_ext_pcc_shared_memory pcc_hdr;
> + struct acpi_pcct_ext_pcc_shared_memory __iomem *pcc_hdr;
>
> if (pchan->type != ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
> return;
> - /* If the memory region has not been mapped, we cannot
> - * determine if we need to send the message, but we still
> - * need to set the cmd_update flag before returning.
> - */
> - if (pchan->chan.shmem == NULL) {
> - pcc_chan_reg_read_modify_write(&pchan->cmd_update);
> - return;
> - }
> - memcpy_fromio(&pcc_hdr, pchan->chan.shmem,
> - sizeof(struct acpi_pcct_ext_pcc_shared_memory));
> +
> + pcc_chan_reg_read_modify_write(&pchan->cmd_update);
> +
> + pcc_hdr = pchan->chan.shmem;

Should use the original code?

memcpy_fromio(&pcc_hdr, pchan->chan.shmem,
sizeof(struct acpi_pcct_ext_pcc_shared_memory));

> +
> /*
> - * The PCC slave subspace channel needs to set the command complete bit
> - * after processing message. If the PCC_ACK_FLAG is set, it should also
> - * ring the doorbell.
> - *
> - * The PCC master subspace channel clears chan_in_use to free channel.
> + * The PCC slave subspace channel needs to set the command
> + * complete bit after processing message. If the PCC_ACK_FLAG
> + * is set, it should also ring the doorbell.
> */
> - if (pcc_hdr.flags & PCC_CMD_COMPLETION_NOTIFY)
> - pcc_send_data(chan, NULL);
> - else
> - pcc_chan_reg_read_modify_write(&pchan->cmd_update);
> + if (ioread32(&pcc_hdr->flags) & PCC_CMD_COMPLETION_NOTIFY)
> + pcc_chan_reg_read_modify_write(&pchan->db);
> }
>
> /**
> @@ -352,7 +341,7 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p)
> pchan->chan_in_use = false;
> mbox_chan_received_data(chan, NULL);
>
> - check_and_ack(pchan, chan);
> + pcc_chan_check_and_ack(pchan);
>
> return IRQ_HANDLED;
> }
>