drm/msm: export hangcheck_period in debugfs

While keeping the previous default value for hangcheck period,
we allow now the possibility of configuring its value via
debugfs.
Signed-off-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Link: https://lore.kernel.org/r/20210607104441.184700-1-siglesias@igalia.comSigned-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/msm_debugfs.c

@@ -226,6 +226,9 @@ void msm_debugfs_init(struct drm_minor *minor)
 	debugfs_create_file("gpu", S_IRUSR, minor->debugfs_root,
 		dev, &msm_gpu_fops);
 
+	debugfs_create_u32("hangcheck_period_ms", 0600, minor->debugfs_root,
+		&priv->hangcheck_period);
+
 	if (priv->kms && priv->kms->funcs->debugfs_init)
 		priv->kms->funcs->debugfs_init(priv->kms, minor);
 }

drivers/gpu/drm/msm/msm_drv.c

@@ -459,6 +459,7 @@ static int msm_drm_init(struct device *dev, const struct drm_driver *drv)
 	mdss = priv->mdss;
 
 	priv->wq = alloc_ordered_workqueue("msm", 0);
+	priv->hangcheck_period = DRM_MSM_HANGCHECK_DEFAULT_PERIOD;
 
 	INIT_LIST_HEAD(&priv->objects);
 	mutex_init(&priv->obj_lock);

drivers/gpu/drm/msm/msm_drv.h

@@ -244,6 +244,9 @@ struct msm_drm_private {
 	struct shrinker shrinker;
 
 	struct drm_atomic_state *pm_state;
+
+	/* For hang detection, in ms */
+	unsigned int hangcheck_period;
 };
 
 struct msm_format {

drivers/gpu/drm/msm/msm_gpu.c

@@ -561,8 +561,9 @@ static void recover_worker(struct kthread_work *work)
 
 static void hangcheck_timer_reset(struct msm_gpu *gpu)
 {
+	struct msm_drm_private *priv = gpu->dev->dev_private;
 	mod_timer(&gpu->hangcheck_timer,
-			round_jiffies_up(jiffies + DRM_MSM_HANGCHECK_JIFFIES));
+			round_jiffies_up(jiffies + msecs_to_jiffies(priv->hangcheck_period)));
 }
 
 static void hangcheck_handler(struct timer_list *t)

drivers/gpu/drm/msm/msm_gpu.h

@@ -122,8 +122,7 @@ struct msm_gpu {
 	 */
 #define DRM_MSM_INACTIVE_PERIOD   66 /* in ms (roughly four frames) */
 
-#define DRM_MSM_HANGCHECK_PERIOD 500 /* in ms */
-#define DRM_MSM_HANGCHECK_JIFFIES msecs_to_jiffies(DRM_MSM_HANGCHECK_PERIOD)
+#define DRM_MSM_HANGCHECK_DEFAULT_PERIOD 500 /* in ms */
 	struct timer_list hangcheck_timer;
 
 	/* work for handling GPU recovery: */