linux-kernel - Re: [PATCH v2 2/7] soc: qcom: smem: Add a feature code getter

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Date: Thu, 18 Apr 2024 11:53:31 +0200
From: Konrad Dybcio <konrad.dybcio@...aro.org>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc: Bjorn Andersson <andersson@...nel.org>, Rob Clark <robdclark@...il.com>,
 Abhinav Kumar <quic_abhinavk@...cinc.com>, Sean Paul <sean@...rly.run>,
 Marijn Suijten <marijn.suijten@...ainline.org>,
 David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>,
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>, linux-arm-msm@...r.kernel.org,
 linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
 freedreno@...ts.freedesktop.org, devicetree@...r.kernel.org,
 Neil Armstrong <neil.armstrong@...aro.org>
Subject: Re: [PATCH v2 2/7] soc: qcom: smem: Add a feature code getter

On 18.04.2024 1:39 AM, Dmitry Baryshkov wrote:
> On Wed, Apr 17, 2024 at 10:02:54PM +0200, Konrad Dybcio wrote:
>> Recent (SM8550+ ish) Qualcomm SoCs have a new mechanism for precisely
>> identifying the specific SKU and the precise speed bin (in the general
>> meaning of this word, anyway): a pair of values called Product Code
>> and Feature Code.
>>
>> Based on this information, we can deduce the available frequencies for
>> things such as Adreno. In the case of Adreno specifically, Pcode is
>> useless for non-prototype SoCs.
>>
>> Introduce a getter for the feature code and export it.
>>
>> Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
>> ---

[...]

>> +/* Internal feature codes */
>> +/* Valid values: 0 <= n <= 0xf */
>> +#define SOCINFO_FC_Yn(n)		(0xf1 + n)
>> +#define SOCINFO_FC_INT_MAX		SOCINFO_FC_Yn(0x10)
> 
> This is 0x101 rather than 0x100 or 0xff. Is that expected?

Yes, this is "the first invalid one", similar to ENUMNAME_NUM

> 
>> +
>> +/* Product codes */
>> +#define SOCINFO_PC_UNKNOWN		0
>> +#define SOCINFO_PCn(n)			(n + 1)
>> +#define SOCINFO_PC_RESERVE		(BIT(31) - 1)
> 
> This patch works on fcodes, why do we have PCode defines here?

I decided they're useful to keep.. Didn't want to split them to a separate
patch for no reason.

Konrad