drm/amdgpu: Respect placement requirements in amdgpu_gtt_mgr functions

When testing intersection and compatibility, respect
the actual placement requirements. This is a pre-requisite
for ensuring that UVD CS BOs do not cross 256M segments.

Fixes: ded910f368 ("drm/amdgpu: Implement intersect/compatible functions")
Suggested-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -272,7 +272,20 @@ static bool amdgpu_gtt_mgr_intersects(struct ttm_resource_manager *man,
 				      const struct ttm_place *place,
 				      size_t size)
 {
-	return !place->lpfn || amdgpu_gtt_mgr_has_gart_addr(res);
+	const struct drm_mm_node *const node = &to_ttm_range_mgr_node(res)->mm_nodes[0];
+	const u32 num_pages = PFN_UP(size);
+
+	if (!place->lpfn)
+		return true;
+
+	if (!amdgpu_gtt_mgr_has_gart_addr(res))
+		return false;
+
+	if (place->fpfn >= (node->start + num_pages) ||
+	    (place->lpfn && place->lpfn <= node->start))
+		return false;
+
+	return true;
 }
 
 /**
@@ -290,7 +303,20 @@ static bool amdgpu_gtt_mgr_compatible(struct ttm_resource_manager *man,
 				      const struct ttm_place *place,
 				      size_t size)
 {
-	return !place->lpfn || amdgpu_gtt_mgr_has_gart_addr(res);
+	const struct drm_mm_node *const node = &to_ttm_range_mgr_node(res)->mm_nodes[0];
+	const u32 num_pages = PFN_UP(size);
+
+	if (!place->lpfn)
+		return true;
+
+	if (!amdgpu_gtt_mgr_has_gart_addr(res))
+		return false;
+
+	if (node->start < place->fpfn ||
+	    (place->lpfn && (node->start + num_pages) > place->lpfn))
+		return false;
+
+	return true;
 }
 
 /**