drm/msm: deprecate MSM_BO_UNCACHED (map as writecombine instead)

There shouldn't be any reason to ever use uncached over writecombine,
so just use writecombine for MSM_BO_UNCACHED.

Note: userspace never used MSM_BO_UNCACHED anyway
Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Acked-by: Jordan Crouse <jordan@cosmicpenguin.net>
Link: https://lore.kernel.org/r/20210423190833.25319-6-jonathan@marek.caSigned-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/msm_gem.c

@@ -213,10 +213,8 @@ void msm_gem_put_pages(struct drm_gem_object *obj)
 
 static pgprot_t msm_gem_pgprot(struct msm_gem_object *msm_obj, pgprot_t prot)
 {
-	if (msm_obj->flags & MSM_BO_WC)
+	if (msm_obj->flags & (MSM_BO_WC|MSM_BO_UNCACHED))
 		return pgprot_writecombine(prot);
-	if (msm_obj->flags & MSM_BO_UNCACHED)
-		return pgprot_noncached(prot);
 	return prot;
 }
 

include/uapi/drm/msm_drm.h

@@ -94,7 +94,7 @@ struct drm_msm_param {
 /* cache modes */
 #define MSM_BO_CACHED        0x00010000
 #define MSM_BO_WC            0x00020000
-#define MSM_BO_UNCACHED      0x00040000
+#define MSM_BO_UNCACHED      0x00040000 /* deprecated, use MSM_BO_WC */
 #define MSM_BO_CACHED_COHERENT 0x080000
 
 #define MSM_BO_FLAGS         (MSM_BO_SCANOUT | \