linux-kernel - Re: [PATCH V2 1/2] ACPI: PCC: add check for platform interrupt

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Date:   Sat, 12 Nov 2022 09:27:20 +0800
From:   "lihuisong (C)" <lihuisong@...wei.com>
To:     Sudeep Holla <sudeep.holla@....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: [PATCH V2 1/2] ACPI: PCC: add check for platform interrupt


在 2022/11/11 22:26, Sudeep Holla 写道:
> Change $subject to:
> "ACPI: PCC: Setup PCC Opregion handler only if platform interrupt is available"
>
> On Fri, Nov 11, 2022 at 10:44:47AM +0800, Huisong Li wrote:
>> Currently, PCC Operation Region driver senses the completion of command by
>> interrupt way. If platform can not generate an interrupt when a command
>> complete, the caller never gets the desired result. So let's reject the
>> setup of the PCC address space on platform that do not support interrupt
>> mode.
>>
> Please reword something like below:
>
> "Currently, PCC OpRegion handler depends on the availability of platform
> interrupt to be functional currently. If it is not available, the OpRegion
> can't be executed successfully or the desired outcome won't be possible.
> So let's reject setting up the PCC OpRegion handler on the platform if
> it doesn't support or have platform interrupt available"
>
>> Signed-off-by: Huisong Li <lihuisong@...wei.com>
>> ---
>>   drivers/acpi/acpi_pcc.c | 47 +++++++++++++++++++++++++----------------
>>   1 file changed, 29 insertions(+), 18 deletions(-)
>>
>> diff --git a/drivers/acpi/acpi_pcc.c b/drivers/acpi/acpi_pcc.c
>> index 3e252be047b8..8efd08e469aa 100644
>> --- a/drivers/acpi/acpi_pcc.c
>> +++ b/drivers/acpi/acpi_pcc.c
>> @@ -53,6 +53,7 @@ acpi_pcc_address_space_setup(acpi_handle region_handle, u32 function,
>>   	struct pcc_data *data;
>>   	struct acpi_pcc_info *ctx = handler_context;
>>   	struct pcc_mbox_chan *pcc_chan;
>> +	static acpi_status ret;
>>   
>>   	data = kzalloc(sizeof(*data), GFP_KERNEL);
>>   	if (!data)
>> @@ -69,23 +70,35 @@ acpi_pcc_address_space_setup(acpi_handle region_handle, u32 function,
>>   	if (IS_ERR(data->pcc_chan)) {
>>   		pr_err("Failed to find PCC channel for subspace %d\n",
>>   		       ctx->subspace_id);
>> -		kfree(data);
>> -		return AE_NOT_FOUND;
>> +		ret = AE_NOT_FOUND;
>> +		goto request_channel_fail;
> The labels are confusing IMO. I would do 's/request_channel_fail/err_free_data/'
> to indicate what is exactly done there rather than just describing what
> failed.
Good idea. Ack.
>
>>   	}
>>   
>>   	pcc_chan = data->pcc_chan;
>> +	if (!pcc_chan->mchan->mbox->txdone_irq) {
>> +		pr_err("This channel-%d does not support interrupt.\n",
>> +		       ctx->subspace_id);
>> +		ret = AE_SUPPORT;
>> +		goto request_channel_fail;
> This is wrong, you must goto "ioremap_fail" as you have been successful in
> opening the channel and now need to free the same.
Sorry, I will fix it in v3.
>
>> +	}
>>   	data->pcc_comm_addr = acpi_os_ioremap(pcc_chan->shmem_base_addr,
>>   					      pcc_chan->shmem_size);
>>   	if (!data->pcc_comm_addr) {
>>   		pr_err("Failed to ioremap PCC comm region mem for %d\n",
>>   		       ctx->subspace_id);
>> -		pcc_mbox_free_channel(data->pcc_chan);
>> -		kfree(data);
>> -		return AE_NO_MEMORY;
>> +		ret = AE_NO_MEMORY;
>> +		goto ioremap_fail;
> Again I prefer 's/ioremap_fail/err_free_channel/' or something similar.
>
> With all the above comments incorporated, you can add:
> Reviewed-by: Sudeep Holla <sudeep.holla@....com>
>