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

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Date:   Tue, 7 Feb 2023 10:27:31 +0800
From:   "lihuisong (C)" <lihuisong@...wei.com>
To:     Sudeep Holla <sudeep.holla@....com>,
        Robbie King <robbiek@...ghtlabs.com>
CC:     <linux-acpi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <rafael@...nel.org>, <rafael.j.wysocki@...el.com>,
        <wanghuiqiang@...wei.com>, <zhangzekun11@...wei.com>,
        <wangxiongfeng2@...wei.com>, <tanxiaofei@...wei.com>,
        <guohanjun@...wei.com>, <xiexiuqi@...wei.com>,
        <wangkefeng.wang@...wei.com>, <huangdaode@...wei.com>
Subject: Re: [RFC-V3 1/2] mailbox: pcc: Add processing platform notification
 for slave subspaces


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@...wei.com>
>> ---
>>   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