[PATCH v2 3/3] drm/xe: Change return type of detect_bar2_dgfx() from s64 to u64

[Shuicheng Lin <shuicheng.lin@intel.com>]

The function never returns a negative value, and the return value is
assigned to a u64 variable. Use u64 for better type correctness
and clarity.

v2: add assert to catch theoretical negative or zero stolen size. (Rodrigo)

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Shuicheng Lin <shuicheng.lin@intel.com>
---
 drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c b/drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c
index 9b00bdc8ef1a..e368b2a36bac 100644
--- a/drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c
+++ b/drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c
@@ -81,7 +81,7 @@ static u32 get_wopcm_size(struct xe_device *xe)
 	return wopcm_size;
 }
 
-static s64 detect_bar2_dgfx(struct xe_device *xe, struct xe_ttm_stolen_mgr *mgr)
+static u64 detect_bar2_dgfx(struct xe_device *xe, struct xe_ttm_stolen_mgr *mgr)
 {
 	struct xe_vram_region *tile_vram = xe_device_get_root_tile(xe)->mem.vram;
 	resource_size_t tile_io_start = xe_vram_region_io_start(tile_vram);
@@ -105,6 +105,8 @@ static s64 detect_bar2_dgfx(struct xe_device *xe, struct xe_ttm_stolen_mgr *mgr)
 		return 0;
 
 	stolen_size = tile_size - mgr->stolen_base;
+
+	xe_assert(xe, stolen_size > wopcm_size);
 	stolen_size -= wopcm_size;
 
 	/* Verify usage fits in the actual resource available */
-- 
2.49.0