drm/amdgpu: Added a few comments for gart

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

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

@@ -259,6 +259,8 @@ int amdgpu_gart_unbind(struct amdgpu_device *adev, uint64_t offset,
  * @offset: offset into the GPU's gart aperture
  * @pages: number of pages to bind
  * @dma_addr: DMA addresses of pages
+ * @flags: page table entry flags
+ * @dst: CPU address of the gart table
  *
  * Map the dma_addresses into GART entries (all asics).
  * Returns 0 for success, -EINVAL for failure.

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

@@ -41,6 +41,7 @@ struct amdgpu_bo;
 
 struct amdgpu_gart {
 	struct amdgpu_bo		*bo;
+	/* CPU kmapped address of gart table */
 	void				*ptr;
 	unsigned			num_gpu_pages;
 	unsigned			num_cpu_pages;