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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 <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Russell King - ARM Linux 2011-01-03 22:36:29 +00:00 committed by Dan Williams
parent 8c8cc2b104
commit 19386b3234
1 changed files with 3 additions and 3 deletions
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6
drivers/dma/amba-pl08x.c
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@ -191,7 +191,7 @@ static void pl08x_set_cregs(struct pl08x_driver_data *pl08x,
{ {
/* Wait for channel inactive */ /* Wait for channel inactive */
while (pl08x_phy_channel_busy(ch)) while (pl08x_phy_channel_busy(ch))
; cpu_relax();
dev_vdbg(&pl08x->adev->dev, dev_vdbg(&pl08x->adev->dev,
"WRITE channel %d: csrc=0x%08x, cdst=0x%08x, " "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 * Do not access config register until channel shows as disabled
*/ */
while (readl(pl08x->base + PL080_EN_CHAN) & (1 << ch->id)) while (readl(pl08x->base + PL080_EN_CHAN) & (1 << ch->id))
; cpu_relax();
/* /*
* Do not access config register until channel shows as inactive * 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 */ /* Wait for channel inactive */
while (pl08x_phy_channel_busy(ch)) while (pl08x_phy_channel_busy(ch))
; cpu_relax();
} }
static void pl08x_resume_phy_chan(struct pl08x_phy_chan *ch) static void pl08x_resume_phy_chan(struct pl08x_phy_chan *ch)