Re: [PATCH v5 1/5] drm/msm/adreno: Implement SMEM-based speed bin

[Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>]

On 7/15/24 10:04 PM, Akhil P Oommen wrote:
> On Tue, Jul 09, 2024 at 12:45:29PM +0200, Konrad Dybcio wrote:
>> On recent (SM8550+) Snapdragon platforms, the GPU speed bin data is
>> abstracted through SMEM, instead of being directly available in a fuse.
>>
>> Add support for SMEM-based speed binning, which includes getting
>> "feature code" and "product code" from said source and parsing them
>> to form something that lets us match OPPs against.
>>
>> Due to the product code being ignored in the context of Adreno on
>> production parts (as of SM8650), hardcode it to SOCINFO_PC_UNKNOWN.
>>
>> Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
>> ---

[...]

>>  
>>  int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
>> @@ -1102,9 +1136,9 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
>>  			devm_pm_opp_set_clkname(dev, "core");
>>  	}
>>  
>> -	if (adreno_read_speedbin(dev, &speedbin) || !speedbin)
>> +	if (adreno_read_speedbin(adreno_gpu, dev, &speedbin) || !speedbin)
>>  		speedbin = 0xffff;
>> -	adreno_gpu->speedbin = (uint16_t) (0xffff & speedbin);
>> +	adreno_gpu->speedbin = speedbin;
> 
> There are some chipsets which uses both Speedbin and Socinfo data for
> SKU detection [1]. We don't need to worry about that logic for now. But
> I am worried about mixing Speedbin and SKU_ID in the UABI with this patch.
> It will be difficult when we have to expose both to userspace.
> 
> I think we can use a separate bitfield to expose FCODE/PCODE. Currently,
> the lower 32 bit is reserved for chipid and 33-48 is reserved for speedbin,
> so I think we can use the rest of the 16 bits for SKU_ID. And within that
> 16bits, 12 bits should be sufficient for FCODE and the rest 8 bits
> reserved for future PCODE.

So I revisited this patchset and had another thought - maybe we could just
extend the speedbin bitfield to cover [63:32] and worry about filling these
higher bits in the future, when adding the platforms you mentioned?

Do we still have plans to use *both* SMEM and fuse encoding on them?

Konrad