From 35e2916f70e3be767c5c8ef6cc80bc5398b8914c Mon Sep 17 00:00:00 2001 From: Shawn Guo Date: Wed, 29 Apr 2015 13:07:03 +0800 Subject: 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 Fixes: 8fb76a07e2cb ("ARM: imx6: set initial power mode in pm function") Tested-by: Kevin Hilman Tested-by: Tyler Baker Signed-off-by: Shawn Guo --- arch/arm/mach-imx/pm-imx6.c | 28 ++++++++++++++++++---------- 1 file changed, 18 insertions(+), 10 deletions(-) (limited to 'arch/arm/mach-imx/pm-imx6.c') diff --git a/arch/arm/mach-imx/pm-imx6.c b/arch/arm/mach-imx/pm-imx6.c index 27bc80dab2d8..b01650d94f91 100644 --- a/arch/arm/mach-imx/pm-imx6.c +++ b/arch/arm/mach-imx/pm-imx6.c @@ -89,7 +89,6 @@ struct imx6_pm_base { struct imx6_pm_socdata { u32 ddr_type; - const char *ccm_compat; const char *mmdc_compat; const char *src_compat; const char *iomuxc_compat; @@ -139,7 +138,6 @@ static const u32 imx6sx_mmdc_io_offset[] __initconst = { }; static const struct imx6_pm_socdata imx6q_pm_data __initconst = { - .ccm_compat = "fsl,imx6q-ccm", .mmdc_compat = "fsl,imx6q-mmdc", .src_compat = "fsl,imx6q-src", .iomuxc_compat = "fsl,imx6q-iomuxc", @@ -149,7 +147,6 @@ static const struct imx6_pm_socdata imx6q_pm_data __initconst = { }; static const struct imx6_pm_socdata imx6dl_pm_data __initconst = { - .ccm_compat = "fsl,imx6q-ccm", .mmdc_compat = "fsl,imx6q-mmdc", .src_compat = "fsl,imx6q-src", .iomuxc_compat = "fsl,imx6dl-iomuxc", @@ -159,7 +156,6 @@ static const struct imx6_pm_socdata imx6dl_pm_data __initconst = { }; static const struct imx6_pm_socdata imx6sl_pm_data __initconst = { - .ccm_compat = "fsl,imx6sl-ccm", .mmdc_compat = "fsl,imx6sl-mmdc", .src_compat = "fsl,imx6sl-src", .iomuxc_compat = "fsl,imx6sl-iomuxc", @@ -169,7 +165,6 @@ static const struct imx6_pm_socdata imx6sl_pm_data __initconst = { }; static const struct imx6_pm_socdata imx6sx_pm_data __initconst = { - .ccm_compat = "fsl,imx6sx-ccm", .mmdc_compat = "fsl,imx6sx-mmdc", .src_compat = "fsl,imx6sx-src", .iomuxc_compat = "fsl,imx6sx-iomuxc", @@ -553,16 +548,11 @@ put_node: static void __init imx6_pm_common_init(const struct imx6_pm_socdata *socdata) { - struct device_node *np; struct regmap *gpr; int ret; - np = of_find_compatible_node(NULL, NULL, socdata->ccm_compat); - ccm_base = of_iomap(np, 0); WARN_ON(!ccm_base); - imx6_set_lpm(WAIT_CLOCKED); - if (IS_ENABLED(CONFIG_SUSPEND)) { ret = imx6q_suspend_init(socdata); if (ret) @@ -583,6 +573,24 @@ static void __init imx6_pm_common_init(const struct imx6_pm_socdata IMX6Q_GPR1_GINT); } +void __init imx6_pm_ccm_init(const char *ccm_compat) +{ + struct device_node *np; + u32 val; + + np = of_find_compatible_node(NULL, NULL, ccm_compat); + ccm_base = of_iomap(np, 0); + BUG_ON(!ccm_base); + + /* + * Initialize CCM_CLPCR_LPM into RUN mode to avoid ARM core + * clock being shut down unexpectedly by WAIT mode. + */ + val = readl_relaxed(ccm_base + CLPCR); + val &= ~BM_CLPCR_LPM; + writel_relaxed(val, ccm_base + CLPCR); +} + void __init imx6q_pm_init(void) { imx6_pm_common_init(&imx6q_pm_data); -- cgit v1.2.3