From: Russell King - ARM Linux Date: Mon, 3 Jan 2011 22:36:29 +0000 (+0000) Subject: ARM: PL08x: ensure loops use cpu_relax() X-Git-Tag: MMI-PSA29.97-13-9~20995^2~11^2~29 X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=19386b3234fdbe4d33492574d83e63a8dace18d3;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git ARM: PL08x: ensure loops use cpu_relax() Tight loops should use cpu_relax() to allow CPUs to reduce power consumption while waiting for events. Signed-off-by: Russell King Acked-by: Linus Walleij Signed-off-by: Dan Williams --- diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c index e8967ff44fc2..78c84b3f903d 100644 --- a/drivers/dma/amba-pl08x.c +++ b/drivers/dma/amba-pl08x.c @@ -191,7 +191,7 @@ static void pl08x_set_cregs(struct pl08x_driver_data *pl08x, { /* Wait for channel inactive */ while (pl08x_phy_channel_busy(ch)) - ; + cpu_relax(); dev_vdbg(&pl08x->adev->dev, "WRITE channel %d: csrc=0x%08x, cdst=0x%08x, " @@ -255,7 +255,7 @@ static void pl08x_enable_phy_chan(struct pl08x_driver_data *pl08x, * Do not access config register until channel shows as disabled */ while (readl(pl08x->base + PL080_EN_CHAN) & (1 << ch->id)) - ; + cpu_relax(); /* * Do not access config register until channel shows as inactive @@ -288,7 +288,7 @@ static void pl08x_pause_phy_chan(struct pl08x_phy_chan *ch) /* Wait for channel inactive */ while (pl08x_phy_channel_busy(ch)) - ; + cpu_relax(); } static void pl08x_resume_phy_chan(struct pl08x_phy_chan *ch)