powerpc/ps3: Replace the flip_ctl logic in ps3av and ps3fb by a mutex

Introduce ps3_gpu_mutex to synchronizes GPU-related operations, like:
  - invoking the L1GPU_CONTEXT_ATTRIBUTE_FB_BLIT command using the
    lv1_gpu_context_attribute() hypervisor call,
  - handling the PS3AV_CID_AVB_PARAM packet in the PS3 A/V Settings driver.

Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/drivers/ps3/ps3av.c b/drivers/ps3/ps3av.c
index 06848b2..5324978 100644
--- a/drivers/ps3/ps3av.c
+++ b/drivers/ps3/ps3av.c
@@ -59,8 +59,6 @@
 		struct ps3av_reply_hdr reply_hdr;
 		u8 raw[PS3AV_BUF_SIZE];
 	} recv_buf;
-	void (*flip_ctl)(int on, void *data);
-	void *flip_data;
 } *ps3av;
 
 /* color space */
@@ -939,24 +937,6 @@
 
 EXPORT_SYMBOL_GPL(ps3av_audio_mute);
 
-void ps3av_register_flip_ctl(void (*flip_ctl)(int on, void *data),
-			     void *flip_data)
-{
-	mutex_lock(&ps3av->mutex);
-	ps3av->flip_ctl = flip_ctl;
-	ps3av->flip_data = flip_data;
-	mutex_unlock(&ps3av->mutex);
-}
-EXPORT_SYMBOL_GPL(ps3av_register_flip_ctl);
-
-void ps3av_flip_ctl(int on)
-{
-	mutex_lock(&ps3av->mutex);
-	if (ps3av->flip_ctl)
-		ps3av->flip_ctl(on, ps3av->flip_data);
-	mutex_unlock(&ps3av->mutex);
-}
-
 static int ps3av_probe(struct ps3_system_bus_device *dev)
 {
 	int res;
diff --git a/drivers/ps3/ps3av_cmd.c b/drivers/ps3/ps3av_cmd.c
index 11eb503..716596e 100644
--- a/drivers/ps3/ps3av_cmd.c
+++ b/drivers/ps3/ps3av_cmd.c
@@ -864,7 +864,7 @@
 {
 	int res;
 
-	ps3av_flip_ctl(0);	/* flip off */
+	mutex_lock(&ps3_gpu_mutex);
 
 	/* avb packet */
 	res = ps3av_do_pkt(PS3AV_CID_AVB_PARAM, send_len, sizeof(*avb),
@@ -878,7 +878,7 @@
 			 res);
 
       out:
-	ps3av_flip_ctl(1);	/* flip on */
+	mutex_unlock(&ps3_gpu_mutex);
 	return res;
 }