OMAP: DSS2: OMAPFB: Add locking for memory regions

Add locking to the memory regions to make sure the memory region size
won't be changed while some other piece of code is performing some
checks or setup based on that information.

Signed-off-by: Ville Syrjälä <ville.syrjala@nokia.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>
diff --git a/drivers/video/omap2/omapfb/omapfb.h b/drivers/video/omap2/omapfb/omapfb.h
index 02f1ba9..db3aef5 100644
--- a/drivers/video/omap2/omapfb/omapfb.h
+++ b/drivers/video/omap2/omapfb/omapfb.h
@@ -52,6 +52,8 @@
 	u8		type;		/* OMAPFB_PLANE_MEM_* */
 	bool		alloc;		/* allocated by the driver */
 	bool		map;		/* kernel mapped by the driver */
+	struct mutex    mtx;
+	unsigned int    ref;
 	atomic_t	map_count;
 };
 
@@ -159,4 +161,20 @@
 	return ovl->set_overlay_info(ovl, &info);
 }
 
+static inline struct omapfb2_mem_region *
+omapfb_get_mem_region(struct omapfb2_mem_region *rg)
+{
+	mutex_lock(&rg->mtx);
+	rg->ref++;
+	mutex_unlock(&rg->mtx);
+	return rg;
+}
+
+static inline void omapfb_put_mem_region(struct omapfb2_mem_region *rg)
+{
+	mutex_lock(&rg->mtx);
+	rg->ref--;
+	mutex_unlock(&rg->mtx);
+}
+
 #endif