[PATCH 04/14] drm/msm/a6xx: Remove both GBIF and RBBM GBIF halt on hw init

[Konrad Dybcio]

Currently we're only deasserting REG_A6XX_RBBM_GBIF_HALT, but we also
need REG_A6XX_GBIF_HALT to be set to 0. For GMU-equipped GPUs this is
done in a6xx_bus_clear_pending_transactions(), but for the GMU-less
ones we have to do it *somewhere*. Unhalting both side by side sounds
like a good plan and it won't cause any issues if it's unnecessary.

Also, add a memory barrier to ensure it's gone through.

Signed-off-by: Konrad Dybcio <konrad.dybcio at linaro.org>
---
 drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index 22dac65cfa8c..158d6453cf3e 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -1004,8 +1004,12 @@ static int hw_init(struct msm_gpu *gpu)
 	}
 
 	/* Clear GBIF halt in case GX domain was not collapsed */
-	if (a6xx_has_gbif(adreno_gpu))
+	if (a6xx_has_gbif(adreno_gpu)) {
+		gpu_write(gpu, REG_A6XX_GBIF_HALT, 0);
 		gpu_write(gpu, REG_A6XX_RBBM_GBIF_HALT, 0);
+		/* Let's make extra sure that the GPU can access the memory.. */
+		mb();
+	}
 
 	gpu_write(gpu, REG_A6XX_RBBM_SECVID_TSB_CNTL, 0);
 
-- 
2.39.1