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| author | Shawn Guo <shawn.guo@linaro.org> | 2015-04-29 13:07:03 +0800 |
|---|---|---|
| committer | Shawn Guo <shawn.guo@linaro.org> | 2015-06-03 14:49:18 +0800 |
| commit | 35e2916f70e3be767c5c8ef6cc80bc5398b8914c (patch) | |
| tree | 9168d5d7f16b86fb402f3d521adf1efd770f04c9 /arch/arm/mach-imx/mach-imx6q.c | |
| parent | de8e434d09f253369621e994da1833703c5c51d6 (diff) | |
| download | linux-35e2916f70e3be767c5c8ef6cc80bc5398b8914c.tar.bz2 | |
ARM: imx6: initialize CCM_CLPCR_LPM into RUN mode earlier
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:
cpuidle_register_governor()
cpuidle_switch_governor()
cpuidle_uninstall_idle_handler()
synchronize_sched()
wait_rcu_gp()
wait_for_completion()
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: Kevin Hilman <khilman@kernel.org>
Fixes: 8fb76a07e2cb ("ARM: imx6: set initial power mode in pm function")
Tested-by: Kevin Hilman <khilman@linaro.org>
Tested-by: Tyler Baker <tyler.baker@linaro.org>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Diffstat (limited to 'arch/arm/mach-imx/mach-imx6q.c')
| -rw-r--r-- | arch/arm/mach-imx/mach-imx6q.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/arm/mach-imx/mach-imx6q.c b/arch/arm/mach-imx/mach-imx6q.c index 3ab61549ce0f..9602cc12d2f1 100644 --- a/arch/arm/mach-imx/mach-imx6q.c +++ b/arch/arm/mach-imx/mach-imx6q.c @@ -393,6 +393,7 @@ static void __init imx6q_init_irq(void) imx_init_l2cache(); imx_src_init(); irqchip_init(); + imx6_pm_ccm_init("fsl,imx6q-ccm"); } static const char * const imx6q_dt_compat[] __initconst = { |