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phy: rockchip-emmc: Wait even longer for the DLL to lock

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Two times out of 2000 reboots I ran into the error message
"rockchip_emmc_phy_power: dllrdy timeout".  Presumably there is some
corner case where the DLL just takes a little longer to timeout.  Let's
give it even more time to handle these corner cases.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Douglas Anderson 2016-06-27 10:39:27 -07:00 committed by Ulf Hansson
parent 4e2ea67086
commit 95cc46fee6
1 changed files with 11 additions and 1 deletions
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12
drivers/phy/phy-rockchip-emmc.c
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@ -206,8 +206,18 @@ static int rockchip_emmc_phy_power(struct phy *phy, bool on_off)
* per the math: 10.2 us * (50000000 Hz / 100000 Hz) => 5.1 ms
* Hopefully we won't be running at 100 kHz, but we should still make
* sure we wait long enough.
*
* NOTE: There appear to be corner cases where the DLL seems to take
* extra long to lock for reasons that aren't understood. In some
* extreme cases we've seen it take up to over 10ms (!). We'll be
* generous and give it 50ms. We still busy wait here because:
* - In most cases it should be super fast.
* - This is not called lots during normal operation so it shouldn't
* be a power or performance problem to busy wait. We expect it
* only at boot / resume. In both cases, eMMC is probably on the
* critical path so busy waiting a little extra time should be OK.
*/
timeout = jiffies + msecs_to_jiffies(10);
timeout = jiffies + msecs_to_jiffies(50);
do {
udelay(1);