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Message-ID: <6aea55e7-2ca6-444c-b111-e3cc45bd28a5@linaro.org>
Date: Thu, 15 Feb 2024 09:58:52 +0100
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From: neil.armstrong@linaro.org
Reply-To: neil.armstrong@linaro.org
Subject: Re: [PATCH 3/5] drm: msm: add support for A750 GPU
To: Konrad Dybcio <konrad.dybcio@linaro.org>, Rob Clark
 <robdclark@gmail.com>, Abhinav Kumar <quic_abhinavk@quicinc.com>,
 Dmitry Baryshkov <dmitry.baryshkov@linaro.org>, Sean Paul <sean@poorly.run>,
 Marijn Suijten <marijn.suijten@somainline.org>,
 David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
 Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
 Maxime Ripard <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>,
 Rob Herring <robh@kernel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
 Conor Dooley <conor+dt@kernel.org>, Will Deacon <will@kernel.org>,
 Robin Murphy <robin.murphy@arm.com>, Joerg Roedel <joro@8bytes.org>,
 Bjorn Andersson <andersson@kernel.org>
Cc: linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
 freedreno@lists.freedesktop.org, devicetree@vger.kernel.org,
 linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
 iommu@lists.linux.dev
References: <20240212-topic-sm8650-gpu-v1-0-708a40b747b5@linaro.org>
 <20240212-topic-sm8650-gpu-v1-3-708a40b747b5@linaro.org>
 <b5d76a25-045a-4acd-ad20-d28855b40222@linaro.org>
 <bcad544c-7ca2-4b4f-805b-4ccaedbd091c@linaro.org>
 <13d65685-b306-43ad-b9ca-a799f2cf73e5@linaro.org>
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On 14/02/2024 22:43, Konrad Dybcio wrote:
> On 12.02.2024 15:45, Neil Armstrong wrote:
>> On 12/02/2024 11:46, Konrad Dybcio wrote:
>>> On 12.02.2024 11:37, Neil Armstrong wrote:
>>>> Add support for the A750 GPU found on the SM8650 platform
>>>>
>>>> Unlike the the very close A740 GPU on the SM8550 SoC, the A750 GPU
>>>> doesn't have an HWCFG block but a separate register set.
>>>>
>>>> The missing registers are added in the a6xx.xml.h file that would
>>>> require a subsequent sync and the non-existent hwcfg is handled
>>>> in a6xx_set_hwcg().
>>>
>>> These should also be submitted to mesa to make sure the next header sync
>>> doesn't wipe them
>>
>> Ack submitting them right now: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27576
> 
> Thanks
> 
>>
>>>
>>> [...]
>>>
>>>> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
>>>> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
>>>> @@ -958,10 +958,11 @@ static void a6xx_set_hwcg(struct msm_gpu *gpu, bool state)
>>>>        struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
>>>>        struct a6xx_gmu *gmu = &a6xx_gpu->gmu;
>>>>        const struct adreno_reglist *reg;
>>>> +    bool skip_programming = !(adreno_gpu->info->hwcg || adreno_is_a7xx(adreno_gpu));
>>>
>>> is_a750?
>>
>> OK right, I was thinking of the next gpu which will probably also miss an hwcfg
>>
>>>
>>>>        unsigned int i;
>>>>        u32 val, clock_cntl_on, cgc_mode;
>>>>    -    if (!adreno_gpu->info->hwcg)
>>>> +    if (skip_programming)
>>>>            return;
>>>>          if (adreno_is_a630(adreno_gpu))
>>>> @@ -982,6 +983,25 @@ static void a6xx_set_hwcg(struct msm_gpu *gpu, bool state)
>>>>                  state ? 0x5555 : 0);
>>>>        }
>>>>    +    if (!adreno_gpu->info->hwcg) {
>>>
>>> I don't think this block of code is reachable now, no?
>>
>> It is because we didn't skip when adreno_is_a7xx(adreno_gpu)
> 
> Ahh I misread the brackets within the assignment
> 
>>
>>>
>>> Maybe remove the skip_programming and if_a750 here?
>> This would require:
>>>> -    if (!adreno_gpu->info->hwcg || )
>>>> +    if (!(adreno_gpu->info->hwcg || adreno_is_a750(adreno_gpu)))
>>
>> and:
>>
>>>> +    if (adreno_is_a750(adreno_gpu)) {
>>
>> But if the next gpu also doesn't have an hwcfg, we will need to use
>> the current design...
>>
>> I just tried with:
>> ====================><===============================
>> @@ -961,7 +961,7 @@ static void a6xx_set_hwcg(struct msm_gpu *gpu, bool state)
>>          unsigned int i;
>>          u32 val, clock_cntl_on, cgc_mode;
>>
>> -       if (!adreno_gpu->info->hwcg)
>> +       if (!(adreno_gpu->info->hwcg || adreno_is_a750(adreno_gpu)))
>>                  return;
>>
>>          if (adreno_is_a630(adreno_gpu))
>> @@ -982,6 +982,25 @@ static void a6xx_set_hwcg(struct msm_gpu *gpu, bool state)
>>                            state ? 0x5555 : 0);
>>          }
>>
>> +       if (adreno_is_a750(adreno_gpu)) {
>> +               gpu_write(gpu, REG_A7XX_RBBM_CLOCK_CNTL_GLOBAL, 1);
>> +               gpu_write(gpu, REG_A7XX_RBBM_CGC_GLOBAL_LOAD_CMD, state ? 1 : 0);
>> +
>> +               if (state) {
>> +                       gpu_write(gpu, REG_A7XX_RBBM_CGC_P2S_TRIG_CMD, 1);
>> +
>> +                       if (gpu_poll_timeout(gpu, REG_A7XX_RBBM_CGC_P2S_STATUS, val,
>> +                                            val & A7XX_RBBM_CGC_P2S_STATUS_TXDONE, 1, 10)) {
>> +                               dev_err(&gpu->pdev->dev, "RBBM_CGC_P2S_STATUS TXDONE Poll failed\n");
>> +                               return;
>> +                       }
>> +
>> +                       gpu_write(gpu, REG_A7XX_RBBM_CLOCK_CNTL_GLOBAL, 0);
>> +               }
>> +
>> +               return;
>> +       }
>> +
>>          val = gpu_read(gpu, REG_A6XX_RBBM_CLOCK_CNTL);
>>
>>          /* Don't re-program the registers if they are already correct */
>> ====================><===============================
>>
>> And it works fine, does it work it for you ?
> 
> Let's keep it as-is in the original submission, as I've mentioned, I had
> misread the code

Ack thanks

Neil

> 
> Konrad
> 
>>
>>>
>>>> +        gpu_write(gpu, REG_A7XX_RBBM_CLOCK_CNTL_GLOBAL, 1);
>>>> +        gpu_write(gpu, REG_A7XX_RBBM_CGC_GLOBAL_LOAD_CMD, state ? 1 : 0);
>>>> +
>>>> +        if (state) {
>>>> +            gpu_write(gpu, REG_A7XX_RBBM_CGC_P2S_TRIG_CMD, 1);
>>>> +
>>>> +            if (gpu_poll_timeout(gpu, REG_A7XX_RBBM_CGC_P2S_STATUS, val,
>>>> +                         val & BIT(0), 1, 10)) {
>>>
>>> We should define that bit name (the err suggests it's
>>> REG_A7XX_RBBM_GCC_P2S_STATUS_TXDONE or so)
>>>
>>> [...]
>>>
>>>> +static inline int adreno_is_a750(struct adreno_gpu *gpu)
>>>> +{
>>>> +    return gpu->info->chip_ids[0] == 0x43051401;
>>>> +}
>>>> +
>>>>    /* Placeholder to make future diffs smaller */
>>>
>>> Please also remove this comment now that it's invalid
>>
>> Ack
>>
>>>
>>> Konrad
>>
>> Thanks,
>> Neil
>>