• Shawn Guo's avatar
    ARM: imx6: initialize CCM_CLPCR_LPM into RUN mode earlier · 35e2916f
    Shawn Guo authored
    Commit 4631960d26da ("ARM: imx6: set initial power mode in pm function")
    moves imx6_set_lpm() from clock init function into
    imx6_pm_common_init().  This causes a hang when cpuidle support is
    enabled.  The reason for that is ARM core clock is shut down
    unexpectedly by WAIT mode.  It happens with the following call stack:
    When wait_for_completion() is called as above, all cores are idle/WFI.
    Hence, the reset value of CCM_CLPCR_LPM - WAIT mode, will trigger a
    hardware shutdown of the ARM core clock.
    To fix the regression, we need to ensure that CCM_CLPCR_LPM is
    initialized into RUN mode earlier than cpuidle governor registration,
    which is a postcore_initcall.  This patch creates function
    imx6_pm_ccm_init() to map CCM block and initialize CCM_CLPCR_LPM into
    RUN mode, and have the function called from machine .init_irq hook,
    which should be early enough.
    Reported-by: default avatarKevin Hilman <khilman@kernel.org>
    Fixes: 8fb76a07
     ("ARM: imx6: set initial power mode in pm function")
    Tested-by: default avatarKevin Hilman <khilman@linaro.org>
    Tested-by: default avatarTyler Baker <tyler.baker@linaro.org>
    Signed-off-by: default avatarShawn Guo <shawn.guo@linaro.org>