[PATCH v2 4/7] drm/msm: Ensure cx gdsc collapse during recovery

[Akhil P Oommen <quic_akhilpo@xxxxxxxxxxx>]

To improve our chance of a successful recovery, we should ensure that
cx headswitch collapses. Cx headswitch might be kept enabled through a
vote from another driver like iommu or even another hardware subsystem.
So, poll the cx gdscr register to ensure that it collapses during
recovery.

Signed-off-by: Akhil P Oommen <quic_akhilpo@xxxxxxxxxxx>
---

(no changes since v1)

 drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 13 ++++++++++++-
 drivers/gpu/drm/msm/msm_gpu.c         |  4 ++++
 drivers/gpu/drm/msm/msm_gpu.h         |  1 +
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index 7ed347c..9aaa469 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -1257,11 +1257,15 @@ static void a6xx_dump(struct msm_gpu *gpu)
 #define VBIF_RESET_ACK_TIMEOUT	100
 #define VBIF_RESET_ACK_MASK	0x00f0
 
+#define CX_GDSCR_OFFSET	0x106c
+#define CX_GDSC_ON_MASK	BIT(31)
+
 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, ret;
+	u32 val;
 
 	adreno_dump_info(gpu);
 
@@ -1288,6 +1292,13 @@ static void a6xx_recover(struct msm_gpu *gpu)
 	/* And the final one from recover worker */
 	pm_runtime_put_sync(&gpu->pdev->dev);
 
+	if (gpu->gpucc_io) {
+		ret = readl_poll_timeout(gpu->gpucc_io + CX_GDSCR_OFFSET, val,
+			!(val & CX_GDSC_ON_MASK), 100, 500000);
+		if (ret)
+			DRM_DEV_INFO(&gpu->pdev->dev, "cx gdsc didn't collapse\n");
+	}
+
 	for (i = gpu->active_submits; i > 0; i--)
 		pm_runtime_get(&gpu->pdev->dev);
 
diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index aa6f34f..7ada0785 100644
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -865,6 +865,10 @@ int msm_gpu_init(struct drm_device *drm, struct platform_device *pdev,
 		goto fail;
 	}
 
+	gpu->gpucc_io = msm_ioremap(pdev, "gpucc");
+	if (IS_ERR(gpu->gpucc_io))
+		gpu->gpucc_io = NULL;
+
 	/* Get Interrupt: */
 	gpu->irq = platform_get_irq(pdev, 0);
 	if (gpu->irq < 0) {
diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h
index 4d935fe..1fe498f 100644
--- a/drivers/gpu/drm/msm/msm_gpu.h
+++ b/drivers/gpu/drm/msm/msm_gpu.h
@@ -226,6 +226,7 @@ struct msm_gpu {
 	int global_faults;
 
 	void __iomem *mmio;
+	void __iomem *gpucc_io;
 	int irq;
 
 	struct msm_gem_address_space *aspace;
-- 
2.7.4