linux-kernel - Re: [PATCH v2 10/21] drm/msm/a8xx: Add support for A8x GMU

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Message-ID: <fcd703e5-d483-4369-8149-a25cc733bc2e@oss.qualcomm.com>
Date: Fri, 14 Nov 2025 01:30:01 +0530
From: Akhil P Oommen <akhilpo@....qualcomm.com>
To: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
Cc: Rob Clark <robin.clark@....qualcomm.com>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>, Sean Paul <sean@...rly.run>,
        Dmitry Baryshkov <lumag@...nel.org>,
        Abhinav Kumar
 <abhinav.kumar@...ux.dev>,
        Jessica Zhang <jesszhan0024@...il.com>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        Jonathan Marek <jonathan@...ek.ca>,
        Jordan Crouse
 <jordan@...micpenguin.net>,
        Will Deacon <will@...nel.org>, Robin Murphy <robin.murphy@....com>,
        Joerg Roedel <joro@...tes.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Connor Abbott <cwabbott0@...il.com>, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-arm-kernel@...ts.infradead.org,
        iommu@...ts.linux.dev, devicetree@...r.kernel.org
Subject: Re: [PATCH v2 10/21] drm/msm/a8xx: Add support for A8x GMU

On 11/13/2025 6:40 PM, Konrad Dybcio wrote:
> On 11/10/25 5:37 PM, Akhil P Oommen wrote:
>> A8x GMU configuration are very similar to A7x. Unfortunately, there are
>> minor shuffling in the register offsets in the GMU CX register region.
>> Apart from that, there is a new HFI message support to pass table like
>> data. This patch adds support for  perf table using this new HFI
>> message.
>>
>> Apart from that, there is a minor rework in a6xx_gmu_rpmh_arc_votes_init()
>> to simplify handling of MxG to MxA fallback along with the additional
>> calculations for the new dependency vote.
>>
>> Signed-off-by: Akhil P Oommen <akhilpo@....qualcomm.com>
>> ---
> 
> [...]
> 
>>  	/* Make sure there are no outstanding RPMh votes */
>> @@ -990,7 +1022,8 @@ static void a6xx_gmu_rpmh_off(struct a6xx_gmu *gmu)
>>  	gmu_poll_timeout_rscc(gmu, REG_A6XX_RSCC_TCS3_DRV0_STATUS + seqmem_off,
>>  		val, (val & 1), 100, 1000);
>>  
>> -	if (!adreno_is_a740_family(adreno_gpu))
>> +
>> +	if (!adreno_is_a740_family(adreno_gpu) && !adreno_is_a8xx(adreno_gpu))
> 
> stray double \n above

Ack

> 
> [...]
> 
>>  	/* Check to see if we are doing a cold or warm boot */
>> -	if (adreno_is_a7xx(adreno_gpu)) {
>> +	if (adreno_is_a7xx(adreno_gpu) || adreno_is_a8xx(adreno_gpu)) {
>>  		status = a6xx_llc_read(a6xx_gpu, REG_A7XX_CX_MISC_TCM_RET_CNTL) == 1 ?
> 
> You skipped writing to this register above - can we count on it
> always being in the right state?

Warmboot is done differently in A8x. We can explore that later. This
fine for now.

> 
> Do we need to map VRB, or is that a topic for the future?

Yes.

-Akhil

> 
> Konrad