drm/ttm: make eviction decision a driver callback v2

This way the driver can decide if it is valuable to evict a BO or not.

The current implementation is added as default to all existing drivers.

v2: fix some typos found during internal testing

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
index 9eb940d..bb6a335 100644
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -47,6 +47,8 @@ struct drm_mm_node;
 
 struct ttm_placement;
 
+struct ttm_place;
+
 /**
  * struct ttm_bus_placement
  *
@@ -396,6 +398,17 @@ extern void ttm_bo_unlock_delayed_workqueue(struct ttm_bo_device *bdev,
 					    int resched);
 
 /**
+ * ttm_bo_eviction_valuable
+ *
+ * @bo: The buffer object to evict
+ * @place: the placement we need to make room for
+ *
+ * Check if it is valuable to evict the BO to make room for the given placement.
+ */
+bool ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
+			      const struct ttm_place *place);
+
+/**
  * ttm_bo_synccpu_write_grab
  *
  * @bo: The buffer object: