video: tegra: host: Force DC reset on stuck DISP syncpt

Call tegra_dc_schedule_reset when DISP syncpoint is stuck for >=
STUCK_FIXUP_COUNT (currently 5) iterations in syncpt_wait_timeout.
This causes display to blank off briefly, but subsequently recovers.

Bug 834337

Change-Id: I564a34e238f5c954f62ecde902af9de22a4cb32f
Reviewed-on: http://git-master/r/42416
Reviewed-by: Niket Sirsi <nsirsi@nvidia.com>
Tested-by: Niket Sirsi <nsirsi@nvidia.com>

3 files changed, 44 insertions, 3 deletions

diff --git a/drivers/video/tegra/dc/dc.c b/drivers/video/tegra/dc/dc.c
index 4e15e0a5d662..05760fe8d4ca 100644
--- a/drivers/video/tegra/dc/dc.c
+++ b/drivers/video/tegra/dc/dc.c
@@ -1731,6 +1731,16 @@ void tegra_dc_disable(struct tegra_dc *dc)
 	mutex_unlock(&dc->lock);
 }
 
+void tegra_dc_schedule_reset(int dc_id)
+{
+	if (dc_id < TEGRA_MAX_DC) {
+		dev_warn(&tegra_dcs[dc_id]->ndev->dev,
+			"%s(%d)\n", __FUNCTION__, dc_id);
+		dump_regs(tegra_dcs[dc_id]);
+		schedule_work(&tegra_dcs[dc_id]->reset_work);
+	}
+}
+
 static void tegra_dc_reset_worker(struct work_struct *work)
 {
 	struct tegra_dc *dc =
diff --git a/drivers/video/tegra/dc/dc_priv.h b/drivers/video/tegra/dc/dc_priv.h
index 7ee19f69c05b..c5d77b338230 100644
--- a/drivers/video/tegra/dc/dc_priv.h
+++ b/drivers/video/tegra/dc/dc_priv.h
@@ -182,4 +182,5 @@ extern struct tegra_dc_out_ops tegra_dc_rgb_ops;
 extern struct tegra_dc_out_ops tegra_dc_hdmi_ops;
 extern struct tegra_dc_out_ops tegra_dc_dsi_ops;
 
+void tegra_dc_schedule_reset(int dc_id);
 #endif
diff --git a/drivers/video/tegra/host/nvhost_syncpt.c b/drivers/video/tegra/host/nvhost_syncpt.c
index c99960381c63..5ec3f09fffc0 100644
--- a/drivers/video/tegra/host/nvhost_syncpt.c
+++ b/drivers/video/tegra/host/nvhost_syncpt.c
@@ -157,6 +157,15 @@ void nvhost_syncpt_incr(struct nvhost_syncpt *sp, u32 id)
 	nvhost_module_idle(&syncpt_to_dev(sp)->mod);
 }
 
+#define MAX_STUCK_CHECK_COUNT	15 /* Maximum number of loops to check for stuck
+				    * syncpoint (this is also affected by the
+				    * wait timeout defined) */
+#define STUCK_FIXUP_COUNT	5  /* Number of stuck syncpoint loops to wait before
+				    * attempting to reset module (if such support
+				    * exists; for now, only DC can be reset) */
+void tegra_dc_schedule_reset(int dc_id);
+
+static u32 nvhost_syncpt_last_min[NV_HOST1X_SYNCPT_NB_PTS];
 /**
  * Main entrypoint for syncpoint value waits.
  */
@@ -165,7 +174,7 @@ int nvhost_syncpt_wait_timeout(struct nvhost_syncpt *sp, u32 id,
 {
 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
 	void *ref;
-	int err = 0;
+	int err = 0, debug_done = 0;
 
 	if (value)
 		*value = 0;
@@ -196,7 +205,6 @@ int nvhost_syncpt_wait_timeout(struct nvhost_syncpt *sp, u32 id,
 		err = -EAGAIN;
 		goto done;
 	}
-
 	/* schedule a wakeup when the syncpoint value is reached */
 	err = nvhost_intr_add_action(&(syncpt_to_dev(sp)->intr), id, thresh,
 				NVHOST_INTR_ACTION_WAKEUP_INTERRUPTIBLE, &wq, &ref);
@@ -223,10 +231,31 @@ int nvhost_syncpt_wait_timeout(struct nvhost_syncpt *sp, u32 id,
 		if (timeout != NVHOST_NO_TIMEOUT)
 			timeout -= check;
 		if (timeout) {
+			u32 min, dc_id;
 			dev_warn(&syncpt_to_dev(sp)->pdev->dev,
 				"syncpoint id %d (%s) stuck waiting %d\n",
 				id, nvhost_syncpt_name(id), thresh);
+			if (debug_done >= STUCK_FIXUP_COUNT) {
+				switch (id) {
+				case NVSYNCPT_DISP0:
+				case NVSYNCPT_DISP1:
+					min = nvhost_syncpt_update_min(sp, id);
+					if (nvhost_syncpt_last_min[id] != 0 &&
+					    nvhost_syncpt_last_min[id] == min) {
+						dc_id = (id == NVSYNCPT_DISP0) ? 0 : 1;
+						/* Seems stuck; it probably hasn't
+						   incremented in prior loops, either */
+						tegra_dc_schedule_reset(dc_id);
+					}
+					break;
+				}
+			}
 			nvhost_syncpt_debug(sp);
+			if (debug_done > MAX_STUCK_CHECK_COUNT) {
+				nvhost_debug_dump();
+				BUG_ON(1);
+			}
+			debug_done++;
 		}
 	};
 	nvhost_intr_put_ref(&(syncpt_to_dev(sp)->intr), ref);
@@ -258,10 +287,11 @@ void nvhost_syncpt_debug(struct nvhost_syncpt *sp)
 		u32 max = nvhost_syncpt_read_max(sp, i);
 		if (!max)
 			continue;
+		nvhost_syncpt_last_min[i] = nvhost_syncpt_update_min(sp, i);
 		dev_info(&syncpt_to_dev(sp)->pdev->dev,
 			"id %d (%s) min %d max %d\n",
 			i, nvhost_syncpt_name(i),
-			nvhost_syncpt_update_min(sp, i), max);
+			nvhost_syncpt_last_min[i], max);
 
 	}
 }