linux-kernel - Re: [PATCH v2 1/2] mailbox: pcc: Add support for platform notification handling

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Date:   Mon, 27 Mar 2023 20:25:04 +0800
From:   "lihuisong (C)" <lihuisong@...wei.com>
To:     Sudeep Holla <sudeep.holla@....com>
CC:     <robbiek@...ghtlabs.com>, <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: [PATCH v2 1/2] mailbox: pcc: Add support for platform
 notification handling


在 2023/3/27 19:30, Sudeep Holla 写道:
> On Tue, Mar 14, 2023 at 07:11:34PM +0800, Huisong Li wrote:
>> Currently, PCC driver doesn't support the processing of platform
>> notification for type 4 PCC subspaces.
>>
>> 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 the Platform.
>>
>> Let us stash the value of the pcc type and use the same while processing
>> the interrupt of the channel. We also need to set the command complete
>> bit and ring doorbell in the interrupt handler for the type 4 channel to
>> complete the communication flow after processing the notification from
>> the Platform.
>>
>> Signed-off-by: Huisong Li <lihuisong@...wei.com>
>> ---
>>   drivers/mailbox/pcc.c | 50 +++++++++++++++++++++++++++++++++++--------
>>   1 file changed, 41 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
>> index 105d46c9801b..a0a87c480d8b 100644
>> --- a/drivers/mailbox/pcc.c
>> +++ b/drivers/mailbox/pcc.c
>> @@ -91,6 +91,7 @@ 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
>> + * @type: PCC subspace type
>>    */
>>   struct pcc_chan_info {
>>   	struct pcc_mbox_chan chan;
>> @@ -100,12 +101,15 @@ struct pcc_chan_info {
>>   	struct pcc_chan_reg cmd_update;
>>   	struct pcc_chan_reg error;
>>   	int plat_irq;
>> +	u8 type;
>>   };
>>   
>>   #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 +225,34 @@ static int pcc_map_interrupt(u32 interrupt, u32 flags)
>>   	return acpi_register_gsi(NULL, interrupt, trigger, polarity);
>>   }
>>   
>> +static bool pcc_mbox_cmd_complete_check(struct pcc_chan_info *pchan)
>> +{
>> +	u64 val;
>> +	int ret;
>> +
>> +	ret = pcc_chan_reg_read(&pchan->cmd_complete, &val);
>> +	if (ret)
>> +		return false;
>> +
>> +	if (!pchan->cmd_complete.gas)
>> +		return true;
>> +
>> +	/*
>> +	 * Judge if the channel respond the interrupt based on the value of
>> +	 * command complete.
>> +	 */
>> +	val &= pchan->cmd_complete.status_mask;
> [super nit] Would prefer an blank line here.
>
Yeah, it would be better if there is an blank line here.
Is it necessary to send v3 for this?