From mboxrd@z Thu Jan 1 00:00:00 1970 From: shawn.guo@linaro.org (Shawn Guo) Date: Wed, 29 Apr 2015 14:04:58 +0800 Subject: [PATCH 05/11] ARM: imx6: set initial power mode in pm function In-Reply-To: References: <1430058672-9267-1-git-send-email-shawn.guo@linaro.org> <1430058672-9267-6-git-send-email-shawn.guo@linaro.org> Message-ID: <20150429060446.GA27573@dragon> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Kevin, On Tue, Apr 28, 2015 at 11:42:48AM -0700, Kevin Hilman wrote: > Hi Shawn, > > On Sun, Apr 26, 2015 at 7:31 AM, Shawn Guo wrote: > > Rather than setting initial low-power mode in every single i.MX6 clock > > initialization function, we should really do that in pm code. Let's > > move imx6q_set_lpm(WAIT_CLOCKED) call into imx6_pm_common_init(). > > > > While at it, let's rename the function to imx6_set_lpm() since it's > > actually common for all i.MX6 SoCs. > > > > Signed-off-by: Shawn Guo > > Some boot failures on imx6[1] (multi_v7_defconfig) were bisected down > to this patch. A simple revert doesn't build, so I was unable tot > test a direct revert. However, from the boot failures you can see > that while multi_v7_defconfig boots fail, the imx_v6_v7_defconfig > boots fine. This reminds me that cpuidle support is not turned on in imx_v6_v7_defconfig. I will send a patch to enable it for testing coverage. > Disabling CONFIG_CPU_IDLE in multi_v7_defconfig allows > this to start booting again on my wandboard quad, so I think there is > something wrong with the cpuidle changes. I just tracked down the issue, and sent a fix like below. The kernelci.org boot automation farm helps. Thanks. Shawn ----8<------------------------------- >>From 056a5da1b56a057762eccd52b5b6b920c7f56b14 Mon Sep 17 00:00:00 2001 From: Shawn Guo Date: Wed, 29 Apr 2015 13:07:03 +0800 Subject: [PATCH] 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: 4631960d26da ("ARM: imx6: set initial power mode in pm function") Signed-off-by: Shawn Guo --- arch/arm/mach-imx/common.h | 1 + arch/arm/mach-imx/mach-imx6q.c | 1 + arch/arm/mach-imx/mach-imx6sl.c | 1 + arch/arm/mach-imx/mach-imx6sx.c | 1 + arch/arm/mach-imx/pm-imx6.c | 28 ++++++++++++++++++---------- 5 files changed, 22 insertions(+), 10 deletions(-) diff --git a/arch/arm/mach-imx/common.h b/arch/arm/mach-imx/common.h index d1e2873f807e..fbd86f1b7f3b 100644 --- a/arch/arm/mach-imx/common.h +++ b/arch/arm/mach-imx/common.h @@ -123,6 +123,7 @@ static inline void v7_cpu_resume(void) {} static inline void imx6_suspend(void __iomem *ocram_vbase) {} #endif +void imx6_pm_ccm_init(const char *ccm_compat); void imx6q_pm_init(void); void imx6dl_pm_init(void); void imx6sl_pm_init(void); 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 = { diff --git a/arch/arm/mach-imx/mach-imx6sl.c b/arch/arm/mach-imx/mach-imx6sl.c index 12a1b098fc6a..300326373166 100644 --- a/arch/arm/mach-imx/mach-imx6sl.c +++ b/arch/arm/mach-imx/mach-imx6sl.c @@ -66,6 +66,7 @@ static void __init imx6sl_init_irq(void) imx_init_l2cache(); imx_src_init(); irqchip_init(); + imx6_pm_ccm_init("fsl,imx6sl-ccm"); } static const char * const imx6sl_dt_compat[] __initconst = { diff --git a/arch/arm/mach-imx/mach-imx6sx.c b/arch/arm/mach-imx/mach-imx6sx.c index f17b7004c24b..6a0b0614de29 100644 --- a/arch/arm/mach-imx/mach-imx6sx.c +++ b/arch/arm/mach-imx/mach-imx6sx.c @@ -86,6 +86,7 @@ static void __init imx6sx_init_irq(void) imx_init_l2cache(); imx_src_init(); irqchip_init(); + imx6_pm_ccm_init("fsl,imx6sx-ccm"); } static void __init imx6sx_init_late(void) 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); -- 1.9.1