OMAP: DSS2: OMAPFB: Add some locking debug checks

Trigger WARN_ON() messages from various places in the code in case the
memory region is not currently locked.
Signed-off-by: Ville Syrjälä <ville.syrjala@nokia.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>

drivers/video/omap2/omapfb/omapfb-ioctl.c

@@ -222,6 +222,7 @@ static int omapfb_setup_mem(struct fb_info *fbi, struct omapfb_mem_info *mi)
 	rg = ofbi->region;
 
 	down_write_nested(&rg->lock, rg->id);
+	atomic_inc(&rg->lock_count);
 
 	if (atomic_read(&rg->map_count)) {
 		r = -EBUSY;
@@ -252,6 +253,7 @@ static int omapfb_setup_mem(struct fb_info *fbi, struct omapfb_mem_info *mi)
 	}
 
  out:
+	atomic_dec(&rg->lock_count);
 	up_write(&rg->lock);
 
 	return r;

drivers/video/omap2/omapfb/omapfb-main.c

@@ -668,6 +668,8 @@ int check_fb_var(struct fb_info *fbi, struct fb_var_screeninfo *var)
 
 	DBG("check_fb_var %d\n", ofbi->id);
 
+	WARN_ON(!atomic_read(&ofbi->region->lock_count));
+
 	r = fb_mode_to_dss_mode(var, &mode);
 	if (r) {
 		DBG("cannot convert var to omap dss mode\n");
@@ -873,6 +875,8 @@ int omapfb_setup_overlay(struct fb_info *fbi, struct omap_overlay *ovl,
 	int rotation = var->rotate;
 	int i;
 
+	WARN_ON(!atomic_read(&ofbi->region->lock_count));
+
 	for (i = 0; i < ofbi->num_overlays; i++) {
 		if (ovl != ofbi->overlays[i])
 			continue;
@@ -966,6 +970,8 @@ int omapfb_apply_changes(struct fb_info *fbi, int init)
 		fill_fb(fbi);
 #endif
 
+	WARN_ON(!atomic_read(&ofbi->region->lock_count));
+
 	for (i = 0; i < ofbi->num_overlays; i++) {
 		ovl = ofbi->overlays[i];
 

drivers/video/omap2/omapfb/omapfb-sysfs.c

@@ -453,6 +453,7 @@ static ssize_t store_size(struct device *dev, struct device_attribute *attr,
 	rg = ofbi->region;
 
 	down_write_nested(&rg->lock, rg->id);
+	atomic_inc(&rg->lock_count);
 
 	if (atomic_read(&rg->map_count)) {
 		r = -EBUSY;
@@ -484,6 +485,7 @@ static ssize_t store_size(struct device *dev, struct device_attribute *attr,
 
 	r = count;
 out:
+	atomic_dec(&rg->lock_count);
 	up_write(&rg->lock);
 
 	unlock_fb_info(fbi);

drivers/video/omap2/omapfb/omapfb.h

@@ -56,6 +56,7 @@ struct omapfb2_mem_region {
 	bool		map;		/* kernel mapped by the driver */
 	atomic_t	map_count;
 	struct rw_semaphore lock;
+	atomic_t	lock_count;
 };
 
 /* appended to fb_info */
@@ -166,11 +167,13 @@ static inline struct omapfb2_mem_region *
 omapfb_get_mem_region(struct omapfb2_mem_region *rg)
 {
 	down_read_nested(&rg->lock, rg->id);
+	atomic_inc(&rg->lock_count);
 	return rg;
 }
 
 static inline void omapfb_put_mem_region(struct omapfb2_mem_region *rg)
 {
+	atomic_dec(&rg->lock_count);
 	up_read(&rg->lock);
 }