[PATCH 19/20] drm/amdgpu:use nop to clear ring buffer

[Monk Liu]

this is for a fine GPU reset/resume, which should
use nop clear ringbuffer prior to kickoff engine.

and also use the same clear macro in ring_init.

Change-Id: I7693891fd4431d64c025d052f1dd0ba797f2f0b7
Signed-off-by: Monk Liu <Monk.Liu at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c | 2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h | 7 +++++++
 drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c    | 1 +
 drivers/gpu/drm/amd/amdgpu/sdma_v3_0.c   | 1 +
 4 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
index 7bacf3c..37d8422 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
@@ -230,7 +230,7 @@ int amdgpu_ring_init(struct amdgpu_device *adev, struct amdgpu_ring *ring,
 			dev_err(adev->dev, "(%d) ring create failed\n", r);
 			return r;
 		}
-		memset((void *)ring->ring, 0, ring->ring_size);
+		amdgpu_ring_clear_ring(ring);
 	}
 	ring->ptr_mask = (ring->ring_size / 4) - 1;
 	ring->max_dw = max_dw;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
index 0e57b04..3fd4ce8 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
@@ -186,5 +186,12 @@ int amdgpu_ring_init(struct amdgpu_device *adev, struct amdgpu_ring *ring,
 		     unsigned ring_size, struct amdgpu_irq_src *irq_src,
 		     unsigned irq_type);
 void amdgpu_ring_fini(struct amdgpu_ring *ring);
+static inline void amdgpu_ring_clear_ring(struct amdgpu_ring *ring)
+{
+	int i = 0;
+	while (i <= ring->ptr_mask)
+		ring->ring[i++] = ring->funcs->nop;
+
+}
 
 #endif
diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
index 5f688d4..0ce00ff 100644
--- a/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
@@ -4509,6 +4509,7 @@ static int gfx_v8_0_cp_gfx_resume(struct amdgpu_device *adev)
 	}
 
 	/* start the ring */
+	amdgpu_ring_clear_ring(ring);
 	gfx_v8_0_cp_gfx_start(adev);
 	ring->ready = true;
 	r = amdgpu_ring_test_ring(ring);
diff --git a/drivers/gpu/drm/amd/amdgpu/sdma_v3_0.c b/drivers/gpu/drm/amd/amdgpu/sdma_v3_0.c
index 9394ca6..d5206f5 100644
--- a/drivers/gpu/drm/amd/amdgpu/sdma_v3_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/sdma_v3_0.c
@@ -615,6 +615,7 @@ static int sdma_v3_0_gfx_resume(struct amdgpu_device *adev)
 
 	for (i = 0; i < adev->sdma.num_instances; i++) {
 		ring = &adev->sdma.instance[i].ring;
+		amdgpu_ring_clear_ring(ring);
 		wb_offset = (ring->rptr_offs * 4);
 
 		mutex_lock(&adev->srbm_mutex);
-- 
2.7.4