Re: [RFC-V3 1/2] mailbox: pcc: Add processing platform notification for slave subspaces

[lihuisong (C)]

在 2023/2/6 23:39, Sudeep Holla 写道:
> Hi Huisong,
>
> Apologies for such a long delay.
>
> Also I would like to hear from Robbie King who I know is playing around
> with this these days 😄. At minimum if this logic works for him as well.

@Robbie King,
Do you use this patchset to test your requirements?
Any other problems? Can you tell us your result?

> On Sat, Dec 03, 2022 at 05:51:49PM +0800, Huisong Li wrote:
> > Currently, PCC driver doesn't support the processing of platform
> > notification for slave PCC subspaces because of the incomplete
> > communication flow.
> >
> > According to ACPI specification, if platform sends a notification
> > to OSPM, it must clear the command complete bit and trigger platform
> > interrupt. OSPM needs to check whether the command complete bit is
> > cleared, clear platform interrupt, process command, and then set the
> > command complete and ring doorbell to Platform. But the current judgment
> > on the command complete is not applicable to type4 in pcc_mbox_irq().
> >
> > This patch introduces a communication flow direction field to detect
> > whether the interrupt belongs to the master or slave subspace channel.
> > And PCC driver needs to add the phase of setting the command complete
> > and ring doorbell in pcc_mbox_irq() to complete type4 communication
> > flow after processing command from Platform.
> >
> > Signed-off-by: Huisong Li <lihuisong@xxxxxxxxxx>
> > ---
> >   drivers/mailbox/pcc.c | 77 +++++++++++++++++++++++++++++++++++++++----
> >   1 file changed, 71 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
> > index 105d46c9801b..ad6d0b7d50fc 100644
> > --- a/drivers/mailbox/pcc.c
> > +++ b/drivers/mailbox/pcc.c
> > @@ -80,6 +80,13 @@ struct pcc_chan_reg {
> >   	u64 status_mask;
> >   };
> >   
> > +enum pcc_chan_comm_flow_dir_type {
> > +	PCC_ONLY_OSPM_TO_PLATFORM,
> > +	PCC_ONLY_PLATFORM_TO_OSPM,
> > +	PCC_BIDIRECTIONAL,
> > +	PCC_DIR_UNKNOWN,
> > +};
> > +
> >   /**
> >    * struct pcc_chan_info - PCC channel specific information
> >    *
> > @@ -91,6 +98,7 @@ struct pcc_chan_reg {
> >    * @cmd_update: PCC register bundle for the command complete update register
> >    * @error: PCC register bundle for the error status register
> >    * @plat_irq: platform interrupt
> > + * @comm_flow_dir: direction of communication flow supported by the channel
> >    */
> >   struct pcc_chan_info {
> >   	struct pcc_mbox_chan chan;
> > @@ -100,12 +108,15 @@ struct pcc_chan_info {
> >   	struct pcc_chan_reg cmd_update;
> >   	struct pcc_chan_reg error;
> >   	int plat_irq;
> > +	u8 comm_flow_dir;
> I would rather just save the 'type' as read from the PCCT. We don't know
> what future types might be and just identifying them by the direction of
> flow of the data, it restricts the usage of this.
Ack.
> >   };
> >   
> >   #define to_pcc_chan_info(c) container_of(c, struct pcc_chan_info, chan)
> >   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
> > @@ -221,6 +232,43 @@ static int pcc_map_interrupt(u32 interrupt, u32 flags)
> >   	return acpi_register_gsi(NULL, interrupt, trigger, polarity);
> >   }
> >   
> > +static bool pcc_chan_need_rsp_irq(struct pcc_chan_info *pchan,
> > +				  u64 cmd_complete_reg_val)
> Probably rename this as pcc_chan_command_complete or something similar.
Ack
> > +{
> > +	bool need_rsp;
> > +
> > +	if (!pchan->cmd_complete.gas)
> > +		return true;
> > +
> > +	cmd_complete_reg_val &= pchan->cmd_complete.status_mask;
> > +
> > +	switch (pchan->comm_flow_dir) {
> Use the channel type instead here.
Ack