drm/radeon: improve ring lockup detection code v2

Use atomics and jiffies_64, so that we don't need to have the
ring mutex locked any more and avoid wrap arounds.

v2: fix some checkpatch warnings

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

2 files changed, 12 insertions, 15 deletions

diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 4581df193932..e98fe5c7f77b 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -805,8 +805,8 @@ struct radeon_ring {
         unsigned                ring_size;
         unsigned                ring_free_dw;
         int                     count_dw;
-        unsigned long           last_activity;
-        unsigned                last_rptr;
+        atomic_t                last_rptr;
+        atomic64_t              last_activity;
         uint64_t                gpu_addr;
         uint32_t                align_mask;
         uint32_t                ptr_mask;
diff --git a/drivers/gpu/drm/radeon/radeon_ring.c b/drivers/gpu/drm/radeon/radeon_ring.c
index b14c86d57607..4c4810272371 100644
--- a/drivers/gpu/drm/radeon/radeon_ring.c
+++ b/drivers/gpu/drm/radeon/radeon_ring.c
@@ -485,8 +485,8 @@ void radeon_ring_unlock_undo(struct radeon_device *rdev, struct radeon_ring *rin
 void radeon_ring_lockup_update(struct radeon_device *rdev,
                                struct radeon_ring *ring)
 {
-        ring->last_rptr = radeon_ring_get_rptr(rdev, ring);
-        ring->last_activity = jiffies;
+        atomic_set(&ring->last_rptr, radeon_ring_get_rptr(rdev, ring));
+        atomic64_set(&ring->last_activity, jiffies_64);
 }
 
 /**
@@ -498,22 +498,19 @@ void radeon_ring_lockup_update(struct radeon_device *rdev,
 bool radeon_ring_test_lockup(struct radeon_device *rdev, struct radeon_ring *ring)
 {
         uint32_t rptr = radeon_ring_get_rptr(rdev, ring);
-        unsigned long cjiffies, elapsed;
+        uint64_t last = atomic64_read(&ring->last_activity);
+        uint64_t elapsed;
 
-        cjiffies = jiffies;
-        if (!time_after(cjiffies, ring->last_activity)) {
-                /* likely a wrap around */
+        if (rptr != atomic_read(&ring->last_rptr)) {
+                /* ring is still working, no lockup */
                 radeon_ring_lockup_update(rdev, ring);
                 return false;
         }
-        if (rptr != ring->last_rptr) {
-                /* CP is still working no lockup */
-                radeon_ring_lockup_update(rdev, ring);
-                return false;
-        }
-        elapsed = jiffies_to_msecs(cjiffies - ring->last_activity);
+
+        elapsed = jiffies_to_msecs(jiffies_64 - last);
         if (radeon_lockup_timeout && elapsed >= radeon_lockup_timeout) {
-                dev_err(rdev->dev, "GPU lockup CP stall for more than %lumsec\n", elapsed);
+                dev_err(rdev->dev, "ring %d stalled for more than %llumsec\n",
+                        ring->idx, elapsed);
                 return true;
         }
         /* give a chance to the GPU ... */