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From:   Konrad Dybcio <konrad.dybcio@linaro.org>
Date:   Wed, 17 May 2023 18:50:09 +0200
Subject: [PATCH 2/6] drm/msm/a6xx: Skip empty protection ranges entries
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Message-Id: <20230517-topic-a7xx_prep-v1-2-7a964f2e99c2@linaro.org>
References: <20230517-topic-a7xx_prep-v1-0-7a964f2e99c2@linaro.org>
In-Reply-To: <20230517-topic-a7xx_prep-v1-0-7a964f2e99c2@linaro.org>
To:     Rob Clark <robdclark@gmail.com>,
        Abhinav Kumar <quic_abhinavk@quicinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Sean Paul <sean@poorly.run>, David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>
Cc:     Marijn Suijten <marijn.suijten@somainline.org>,
        linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
        freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        Konrad Dybcio <konrad.dybcio@linaro.org>
Precedence: bulk

Some specific SKUs leave certain protection range registers empty.
Allow for that behavior.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
 drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index deed42675fe2..8707e8b6ac7e 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -778,8 +778,11 @@ static void a6xx_set_cp_protect(struct msm_gpu *gpu)
 	 */
 	gpu_write(gpu, REG_A6XX_CP_PROTECT_CNTL, BIT(0) | BIT(1) | BIT(3));
 
-	for (i = 0; i < count - 1; i++)
-		gpu_write(gpu, REG_A6XX_CP_PROTECT(i), regs[i]);
+	for (i = 0; i < count - 1; i++) {
+		/* Intentionally skip writing to some registers */
+		if (regs[i])
+			gpu_write(gpu, REG_A6XX_CP_PROTECT(i), regs[i]);
+	}
 	/* last CP_PROTECT to have "infinite" length on the last entry */
 	gpu_write(gpu, REG_A6XX_CP_PROTECT(count_max - 1), regs[i]);
 }

-- 
2.40.1