drm/amdgpu: add begin/end_use ring callbacks

For manual UVD/VCE power and clock gating.

Signed-off-by: Christian König <[e-mail]>
Reviewed-by: Edward O'Callaghan <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdgpu/amdgpu.h

···
 	void (*pad_ib)(struct amdgpu_ring *ring, struct amdgpu_ib *ib);
 	unsigned (*init_cond_exec)(struct amdgpu_ring *ring);
 	void (*patch_cond_exec)(struct amdgpu_ring *ring, unsigned offset);
+	/* note usage for clock and power gating */
+	void (*begin_use)(struct amdgpu_ring *ring);
+	void (*end_use)(struct amdgpu_ring *ring);
 };
 
 /*

drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c

···
 
 	ring->count_dw = ndw;
 	ring->wptr_old = ring->wptr;
+
+	if (ring->funcs->begin_use)
+		ring->funcs->begin_use(ring);
+
 	return 0;
 }
 
···
 
 	mb();
 	amdgpu_ring_set_wptr(ring);
+
+	if (ring->funcs->end_use)
+		ring->funcs->end_use(ring);
 }
 
 /**
···
 void amdgpu_ring_undo(struct amdgpu_ring *ring)
 {
 	ring->wptr = ring->wptr_old;
+
+	if (ring->funcs->end_use)
+		ring->funcs->end_use(ring);
 }
 
 /**