linux-kernel - Re: [PATCH v4 1/6] ACPI: CPPC: Add IS_OPTIONAL_CPC

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Message-ID: <c021a12a-ce3c-4266-8bc1-dc8b20525b9a@huawei.com>
Date: Wed, 15 Jan 2025 15:52:05 +0800
From: "zhenglifeng (A)" <zhenglifeng1@...wei.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>
CC: <lenb@...nel.org>, <robert.moore@...el.com>, <viresh.kumar@...aro.org>,
	<mario.limonciello@....com>, <gautham.shenoy@....com>, <ray.huang@....com>,
	<pierre.gondois@....com>, <acpica-devel@...ts.linux.dev>,
	<linux-acpi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-pm@...r.kernel.org>, <linuxarm@...wei.com>,
	<jonathan.cameron@...wei.com>, <zhanjie9@...ilicon.com>,
	<lihuisong@...wei.com>, <hepeng68@...wei.com>, <fanghao11@...wei.com>
Subject: Re: [PATCH v4 1/6] ACPI: CPPC: Add IS_OPTIONAL_CPC_REG macro

On 2025/1/14 21:27, Rafael J. Wysocki wrote:

> On Mon, Jan 13, 2025 at 1:21 PM Lifeng Zheng <zhenglifeng1@...wei.com> wrote:
>>
>> Add IS_OPTIONAL_CPC_REG macro to judge if a cpc_reg is an optional one.
> 
> This requires a bit more explanation, especially what's the purpose of
> it (ie. the "why").

Will add more explanation. Thanks.

> 
>> Signed-off-by: Lifeng Zheng <zhenglifeng1@...wei.com>
>> ---
>>  drivers/acpi/cppc_acpi.c | 6 ++++++
>>  1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
>> index f193e713825a..6454b469338f 100644
>> --- a/drivers/acpi/cppc_acpi.c
>> +++ b/drivers/acpi/cppc_acpi.c
>> @@ -129,6 +129,12 @@ static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr);
>>  #define CPC_SUPPORTED(cpc) ((cpc)->type == ACPI_TYPE_INTEGER ?         \
>>                                 !!(cpc)->cpc_entry.int_value :          \
>>                                 !IS_NULL_REG(&(cpc)->cpc_entry.reg))
>> +
>> +/* These indicate optional of the per-cpu cpc_regs[]. */
> 
> Again, you need to say more here, like how this is supposed to work.

Will add it. Thanks.

> 
>> +#define REG_OPTIONAL (0b111111100011111010000)
> 
> A hex literal would work too AFAICS.

Will change it. Thanks.

> 
>> +
>> +#define IS_OPTIONAL_CPC_REG(reg_idx) (REG_OPTIONAL & (1U << (reg_idx)))
> 
> You need to explain what reg_idx is.

Will add more annotations. Thanks.

> 
>> +
>>  /*
>>   * Arbitrary Retries in case the remote processor is slow to respond
>>   * to PCC commands. Keeping it high enough to cover emulators where
>> --