This function is added to map the ring to sdma instance
Signed-off-by: Jammy Zhou <Jammy.Zhou@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
        ring->ring_free_dw--;
 }
 
+static inline struct amdgpu_sdma * amdgpu_get_sdma_instance(struct amdgpu_ring *ring)
+{
+       struct amdgpu_device *adev = ring->adev;
+       int i;
+
+       for (i = 0; i < AMDGPU_MAX_SDMA_INSTANCES; i++)
+               if (&adev->sdma[i].ring == ring)
+                       break;
+
+       if (i < AMDGPU_MAX_SDMA_INSTANCES)
+               return &adev->sdma[i];
+       else
+               return NULL;
+}
+
 /*
  * ASICs macro.
  */