[PATCH V7 4/9] drm/amdgpu: Introduce cached_rptr and is_guilty callback in amdgpu_ring

[jesse.zhang at amd.com]

From: "Jesse.zhang at amd.com" <Jesse.zhang at amd.com>

This patch introduces the following changes:
- Add `cached_rptr` to the `amdgpu_ring` structure to store the read pointer before a reset.
- Add `is_guilty` callback to the `amdgpu_ring_funcs` structure to check if a ring is guilty of causing a timeout.

Suggested-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Jesse Zhang <jesse.zhang at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c | 2 ++
 drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
index a6e28fe3f8d6..20cd21df38ba 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
@@ -342,6 +342,8 @@ int amdgpu_ring_init(struct amdgpu_device *adev, struct amdgpu_ring *ring,
 	ring->buf_mask = (ring->ring_size / 4) - 1;
 	ring->ptr_mask = ring->funcs->support_64bit_ptrs ?
 		0xffffffffffffffff : ring->buf_mask;
+	/*  Initialize cached_rptr to 0 */
+	ring->cached_rptr = 0;
 
 	/* Allocate ring buffer */
 	if (ring->is_mes_queue) {
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
index 04af26536f97..182aa535d395 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
@@ -237,6 +237,7 @@ struct amdgpu_ring_funcs {
 	void (*patch_de)(struct amdgpu_ring *ring, unsigned offset);
 	int (*reset)(struct amdgpu_ring *ring, unsigned int vmid);
 	void (*emit_cleaner_shader)(struct amdgpu_ring *ring);
+	bool (*is_guilty)(struct amdgpu_ring *ring);
 };
 
 struct amdgpu_ring {
@@ -306,6 +307,8 @@ struct amdgpu_ring {
 
 	bool            is_sw_ring;
 	unsigned int    entry_index;
+	/* store the cached rptr to restore after reset */
+	uint64_t cached_rptr;
 
 };
 
-- 
2.25.1