drm/msm: Fix cx collapse issue during recovery

There are some hardware logic under CX domain. For a successful
recovery, we should ensure cx headswitch collapses to ensure all the
stale states are cleard out. This is especially true to for a6xx family
where we can GMU co-processor.

Currently, cx doesn't collapse due to a devlink between gpu and its
smmu. So the *struct gpu device* needs to be runtime suspended to ensure
that the iommu driver removes its vote on cx gdsc.
Signed-off-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/498398/
Link: https://lore.kernel.org/r/20220819015030.v5.4.I4ac27a0b34ea796ce0f938bb509e257516bc6f57@changeidSigned-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/adreno/a6xx_gpu.c

@@ -1261,7 +1261,7 @@ static void a6xx_recover(struct msm_gpu *gpu)
 {
 	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
 	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
-	int i;
+	int i, active_submits;
 
 	adreno_dump_info(gpu);
 
@@ -1278,8 +1278,34 @@ static void a6xx_recover(struct msm_gpu *gpu)
 	 */
 	gmu_write(&a6xx_gpu->gmu, REG_A6XX_GMU_GMU_PWR_COL_KEEPALIVE, 0);
 
-	gpu->funcs->pm_suspend(gpu);
-	gpu->funcs->pm_resume(gpu);
+	pm_runtime_dont_use_autosuspend(&gpu->pdev->dev);
+
+	/* active_submit won't change until we make a submission */
+	mutex_lock(&gpu->active_lock);
+	active_submits = gpu->active_submits;
+
+	/*
+	 * Temporarily clear active_submits count to silence a WARN() in the
+	 * runtime suspend cb
+	 */
+	gpu->active_submits = 0;
+
+	/* Drop the rpm refcount from active submits */
+	if (active_submits)
+		pm_runtime_put(&gpu->pdev->dev);
+
+	/* And the final one from recover worker */
+	pm_runtime_put_sync(&gpu->pdev->dev);
+
+	pm_runtime_use_autosuspend(&gpu->pdev->dev);
+
+	if (active_submits)
+		pm_runtime_get(&gpu->pdev->dev);
+
+	pm_runtime_get_sync(&gpu->pdev->dev);
+
+	gpu->active_submits = active_submits;
+	mutex_unlock(&gpu->active_lock);
 
 	msm_gpu_hw_init(gpu);
 }

drivers/gpu/drm/msm/msm_gpu.c

@@ -422,9 +422,7 @@ static void recover_worker(struct kthread_work *work)
 		/* retire completed submits, plus the one that hung: */
 		retire_submits(gpu);
 
-		pm_runtime_get_sync(&gpu->pdev->dev);
 		gpu->funcs->recover(gpu);
-		pm_runtime_put_sync(&gpu->pdev->dev);
 
 		/*
 		 * Replay all remaining submits starting with highest priority
@@ -441,7 +439,7 @@ static void recover_worker(struct kthread_work *work)
 		}
 	}
 
-	pm_runtime_put_sync(&gpu->pdev->dev);
+	pm_runtime_put(&gpu->pdev->dev);
 
 	mutex_unlock(&gpu->lock);