block/ps3: fix slow VRAM IO
The current PS3 VRAM driver uses msleep() to wait for completion of RSX
DMA transfers between system memory and VRAM. Depending on the system
timing, the processing delay and overhead of this msleep() call can
significantly impact VRAM driver IO.
To avoid the condition, add a short duration (200 usec max) udelay()
polling loop before entering the msleep() polling loop.
Signed-off-by: Hideyuki Sasaki <xhide@rd.scei.sony.co.jp>
Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
Acked-by: Jim Paris <jim@jtan.com>
Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/block/ps3vram.c b/drivers/block/ps3vram.c
index 3bb7c47..1fb6c31 100644
--- a/drivers/block/ps3vram.c
+++ b/drivers/block/ps3vram.c
@@ -123,7 +123,15 @@
{
struct ps3vram_priv *priv = ps3_system_bus_get_drvdata(dev);
u32 *notify = ps3vram_get_notifier(priv->reports, NOTIFIER);
- unsigned long timeout = jiffies + msecs_to_jiffies(timeout_ms);
+ unsigned long timeout;
+
+ for (timeout = 20; timeout; timeout--) {
+ if (!notify[3])
+ return 0;
+ udelay(10);
+ }
+
+ timeout = jiffies + msecs_to_jiffies(timeout_ms);
do {
if (!notify[3])