Re: [PATCH 1/6] drm/msm/a6xx: Add support for Adreno 612

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

On 10/24/25 3:16 PM, Rob Clark wrote:
> On Fri, Oct 24, 2025 at 12:55 AM Konrad Dybcio
> <konrad.dybcio@oss.qualcomm.com> wrote:
>>
>> On 10/24/25 12:57 AM, Akhil P Oommen wrote:
>>> On 10/22/2025 8:43 PM, Konrad Dybcio wrote:
>>>> On 10/17/25 7:08 PM, Akhil P Oommen wrote:
>>>>> From: Jie Zhang <quic_jiezh@quicinc.com>
>>>>>
>>>>> Add support for Adreno 612 GPU found in SM6150/QCS615 chipsets.
>>>>> A612 falls under ADRENO_6XX_GEN1 family and is a cut down version
>>>>> of A615 GPU.
>>>>>
>>>>> A612 has a new IP called Reduced Graphics Management Unit or RGMU
>>>>> which is a small state machine which helps to toggle GX GDSC
>>>>> (connected to CX rail) to implement IFPC feature. It doesn't support
>>>>> any other features of a full fledged GMU like clock control, resource
>>>>> voting to rpmh etc. So we need linux clock driver support like other
>>>>> gmu-wrapper implementations to control gpu core clock and gpu GX gdsc.
>>>>> This patch skips RGMU core initialization and act more like a
>>>>> gmu-wrapper case.
>>>>>
>>>>> Co-developed-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
>>>>> Signed-off-by: Jie Zhang <quic_jiezh@quicinc.com>
>>>>> Signed-off-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
>>>>> ---
>>>>
>>>> [...]
>>>>
>>>>> @@ -350,12 +350,18 @@ static const struct a6xx_gmu_oob_bits a6xx_gmu_oob_bits[] = {
>>>>>  /* Trigger a OOB (out of band) request to the GMU */
>>>>>  int a6xx_gmu_set_oob(struct a6xx_gmu *gmu, enum a6xx_gmu_oob_state state)
>>>>>  {
>>>>> +   struct a6xx_gpu *a6xx_gpu = container_of(gmu, struct a6xx_gpu, gmu);
>>>>> +   struct adreno_gpu *adreno_gpu = &a6xx_gpu->base;
>>>>>     int ret;
>>>>>     u32 val;
>>>>>     int request, ack;
>>>>>
>>>>>     WARN_ON_ONCE(!mutex_is_locked(&gmu->lock));
>>>>>
>>>>> +   /* Skip OOB calls since RGMU is not enabled */
>>>>
>>>> "RGMU doesn't handle OOB calls"
>>>
>>> Technically RGMU can handle OOB calls. But we are not initializing rgmu.
>>
>> Oh, I glossed over that..
>>
>> IIRC the reason we delayed 612 support in the past was to make sure
>> that the RGMU FW is consumed, so that runtime requirements don't
>> suddenly change one day.
>>
>> If you have no interest/way in getting it wholly supported right now,
>> can you at least make sure that the driver requests the firmware and
>> exits if it's absent?
> 
> adreno_load_gpu() calls adreno_load_fw() first thing, and will bail if
> gmu fw is missing.  (zap fw is a bit more awkward since that could
> come from dt or device table.)

Indeed you're right

Konrad