drm/amdgpu: fix broken debug sdma vram access function

Debug VRAM access through SDMA has several broken parts resulting in
silent MMIO fallback.

BO kernel creation takes the location of the cpu addr pointer, not
the pointer itself for address kmap.

drm_dev_enter return true on success so change access check.

The source BO is reserved but not pinned so find the address using the
cursor offset relative to its memory domain start.
Signed-off-by: Jonathan Kim <jonathan.kim@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1406,6 +1406,7 @@ static int amdgpu_ttm_access_memory_sdma(struct ttm_buffer_object *bo,
 {
 	struct amdgpu_bo *abo = ttm_to_amdgpu_bo(bo);
 	struct amdgpu_device *adev = amdgpu_ttm_adev(abo->tbo.bdev);
+	struct amdgpu_res_cursor src_mm;
 	struct amdgpu_job *job;
 	struct dma_fence *fence;
 	uint64_t src_addr, dst_addr;
@@ -1418,9 +1419,8 @@ static int amdgpu_ttm_access_memory_sdma(struct ttm_buffer_object *bo,
 	if (!adev->mman.sdma_access_ptr)
 		return -EACCES;
 
-	r = drm_dev_enter(adev_to_drm(adev), &idx);
-	if (r)
-		return r;
+	if (!drm_dev_enter(adev_to_drm(adev), &idx))
+		return -ENODEV;
 
 	if (write)
 		memcpy(adev->mman.sdma_access_ptr, buf, len);
@@ -1430,7 +1430,8 @@ static int amdgpu_ttm_access_memory_sdma(struct ttm_buffer_object *bo,
 	if (r)
 		goto out;
 
-	src_addr = amdgpu_bo_gpu_offset(abo);
+	amdgpu_res_first(abo->tbo.resource, offset, len, &src_mm);
+	src_addr = amdgpu_ttm_domain_start(adev, bo->resource->mem_type) + src_mm.start;
 	dst_addr = amdgpu_bo_gpu_offset(adev->mman.sdma_access_bo);
 	if (write)
 		swap(src_addr, dst_addr);
@@ -1828,7 +1829,7 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
 	if (amdgpu_bo_create_kernel(adev, PAGE_SIZE, PAGE_SIZE,
 				AMDGPU_GEM_DOMAIN_GTT,
 				&adev->mman.sdma_access_bo, NULL,
-				adev->mman.sdma_access_ptr))
+				&adev->mman.sdma_access_ptr))
 		DRM_WARN("Debug VRAM access will use slowpath MM access\n");
 
 	return 0;
@@ -1852,6 +1853,8 @@ void amdgpu_ttm_fini(struct amdgpu_device *adev)
 	if (adev->mman.stolen_reserved_size)
 		amdgpu_bo_free_kernel(&adev->mman.stolen_reserved_memory,
 				      NULL, NULL);
+	amdgpu_bo_free_kernel(&adev->mman.sdma_access_bo, NULL,
+					&adev->mman.sdma_access_ptr);
 	amdgpu_ttm_fw_reserve_vram_fini(adev);
 
 	if (drm_dev_enter(adev_to_drm(adev), &idx)) {
@@ -1871,8 +1874,6 @@ void amdgpu_ttm_fini(struct amdgpu_device *adev)
 	ttm_range_man_fini(&adev->mman.bdev, AMDGPU_PL_OA);
 	ttm_device_fini(&adev->mman.bdev);
 	adev->mman.initialized = false;
-	amdgpu_bo_free_kernel(&adev->mman.sdma_access_bo, NULL,
-					&adev->mman.sdma_access_ptr);
 	DRM_INFO("amdgpu: ttm finalized\n");
 }