linux-kernel - [PATCH 4/6] drm/msm/a6xx: Improve GMU force shutdown sequence

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Message-Id: <20230517-topic-a7xx_prep-v1-4-7a964f2e99c2@linaro.org>
Date:   Wed, 17 May 2023 18:50:11 +0200
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>
Cc:     Marijn Suijten <marijn.suijten@...ainline.org>,
        linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Konrad Dybcio <konrad.dybcio@...aro.org>
Subject: [PATCH 4/6] drm/msm/a6xx: Improve GMU force shutdown sequence

The GMU force shutdown sequence involves some additional register cleanup
which was not implemented previously. Do so.

Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
---
 drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
index ea6d671e7c6c..8004b582e45f 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
@@ -930,6 +930,13 @@ static void a6xx_gmu_force_off(struct a6xx_gmu *gmu)
 	/* Make sure there are no outstanding RPMh votes */
 	a6xx_gmu_rpmh_off(gmu);
 
+	/* Clear the WRITEDROPPED fields and put fence into allow mode */
+	gmu_write(gmu, REG_A6XX_GMU_AHB_FENCE_STATUS_CLR, 0x7);
+	gmu_write(gmu, REG_A6XX_GMU_AO_AHB_FENCE_CTRL, 0);
+
+	/* Make sure the above writes go through */
+	wmb();
+
 	/* Halt the gmu cm3 core */
 	gmu_write(gmu, REG_A6XX_GMU_CM3_SYSRESET, 1);
 

-- 
2.40.1