drm/radeon: update rptr saving logic for memory buffers

Add support for using memory buffers rather than
scratch registers.  Some rings may not be able to
write to scratch registers.

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

1 files changed, 29 insertions, 2 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_ring.c b/drivers/gpu/drm/radeon/radeon_ring.c
index c5828b90902..c1efde6d53d 100644
--- a/drivers/gpu/drm/radeon/radeon_ring.c
+++ b/drivers/gpu/drm/radeon/radeon_ring.c
@@ -207,6 +207,19 @@ void radeon_ring_write(struct radeon_ring *ring, uint32_t v)
         ring->ring_free_dw--;
 }
 
+bool radeon_ring_supports_scratch_reg(struct radeon_device *rdev,
+                                      struct radeon_ring *ring)
+{
+        switch (ring->idx) {
+        case RADEON_RING_TYPE_GFX_INDEX:
+        case CAYMAN_RING_TYPE_CP1_INDEX:
+        case CAYMAN_RING_TYPE_CP2_INDEX:
+                return true;
+        default:
+                return false;
+        }
+}
+
 void radeon_ring_free_size(struct radeon_device *rdev, struct radeon_ring *ring)
 {
         u32 rptr;
@@ -372,7 +385,7 @@ unsigned radeon_ring_backup(struct radeon_device *rdev, struct radeon_ring *ring
         mutex_lock(&rdev->ring_lock);
         *data = NULL;
 
-        if (ring->ring_obj == NULL || !ring->rptr_save_reg) {
+        if (ring->ring_obj == NULL) {
                 mutex_unlock(&rdev->ring_lock);
                 return 0;
         }
@@ -384,7 +397,16 @@ unsigned radeon_ring_backup(struct radeon_device *rdev, struct radeon_ring *ring
         }
 
         /* calculate the number of dw on the ring */
-        ptr = RREG32(ring->rptr_save_reg);
+        if (ring->rptr_save_reg)
+                ptr = RREG32(ring->rptr_save_reg);
+        else if (rdev->wb.enabled)
+                ptr = le32_to_cpu(*ring->next_rptr_cpu_addr);
+        else {
+                /* no way to read back the next rptr */
+                mutex_unlock(&rdev->ring_lock);
+                return 0;
+        }
+
         size = ring->wptr + (ring->ring_size / 4);
         size -= ptr;
         size &= ring->ptr_mask;
@@ -478,6 +500,11 @@ int radeon_ring_init(struct radeon_device *rdev, struct radeon_ring *ring, unsig
         }
         ring->ptr_mask = (ring->ring_size / 4) - 1;
         ring->ring_free_dw = ring->ring_size / 4;
+        if (rdev->wb.enabled) {
+                u32 index = RADEON_WB_RING0_NEXT_RPTR + (ring->idx * 4);
+                ring->next_rptr_gpu_addr = rdev->wb.gpu_addr + index;
+                ring->next_rptr_cpu_addr = &rdev->wb.wb[index/4];
+        }
         if (radeon_debugfs_ring_init(rdev, ring)) {
                 DRM_ERROR("Failed to register debugfs file for rings !\n");
         }