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ARM: imx: clk-pllv3: improve the timeout waiting method

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There are two improvements for this commit:

- Add comparing pll lock condition after while loop. It can
fix potential fake timeout problem caused by the code is just
scheduled out before compare the timeout, and the time of
scheduling out are more than one jiffies.

- Move timeout assignment more close to compare the timeout.
It can reduce the possibility the code is scheduled out, and
the timeout can be more precise.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
This commit is contained in:
Peter Chen 2013-07-16 10:23:20 +08:00 committed by Shawn Guo
parent dfd871442e
commit 0a03638852
1 changed files with 11 additions and 4 deletions
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15
arch/arm/mach-imx/clk-pllv3.c
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@ -48,7 +48,7 @@ struct clk_pllv3 {
static int clk_pllv3_prepare(struct clk_hw *hw)
{
struct clk_pllv3 *pll = to_clk_pllv3(hw);
unsigned long timeout = jiffies + msecs_to_jiffies(10);
unsigned long timeout;
u32 val;
val = readl_relaxed(pll->base);
@ -59,12 +59,19 @@ static int clk_pllv3_prepare(struct clk_hw *hw)
val &= ~BM_PLL_POWER;
writel_relaxed(val, pll->base);
timeout = jiffies + msecs_to_jiffies(10);
/* Wait for PLL to lock */
while (!(readl_relaxed(pll->base) & BM_PLL_LOCK))
do {
if (readl_relaxed(pll->base) & BM_PLL_LOCK)
break;
if (time_after(jiffies, timeout))
return -ETIMEDOUT;
break;
} while (1);
return 0;
if (readl_relaxed(pll->base) & BM_PLL_LOCK)
return 0;
else
return -ETIMEDOUT;
}
static void clk_pllv3_unprepare(struct clk_hw *hw)