drm/ttm: Helper function to get TTM mem limit

Add a helper function to get TTM memory limit. This is
needed by KFD to set its own internal memory limits.

Signed-off-by: Mukul Joshi <mukul.joshi@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/ttm/ttm_tt.c

@@ -450,3 +450,9 @@ ttm_kmap_iter_tt_init(struct ttm_kmap_iter_tt *iter_tt,
 	return &iter_tt->base;
 }
 EXPORT_SYMBOL(ttm_kmap_iter_tt_init);
+
+unsigned long ttm_tt_pages_limit(void)
+{
+	return ttm_pages_limit;
+}
+EXPORT_SYMBOL(ttm_tt_pages_limit);

include/drm/ttm/ttm_tt.h

@@ -222,7 +222,7 @@ void ttm_tt_mgr_init(unsigned long num_pages, unsigned long num_dma32_pages);
 
 struct ttm_kmap_iter *ttm_kmap_iter_tt_init(struct ttm_kmap_iter_tt *iter_tt,
 					    struct ttm_tt *tt);
-
+unsigned long ttm_tt_pages_limit(void);
 #if IS_ENABLED(CONFIG_AGP)
 #include <linux/agp_backend.h>