[FIX][RESEND PATCH v3] ARM: EXYNOS: Fix suspend/resume sequences
Bartlomiej Zolnierkiewicz
b.zolnierkie at samsung.com
Fri Aug 1 04:01:18 PDT 2014
Hi,
On Friday, August 01, 2014 10:51:37 AM Tomasz Figa wrote:
> From: Tomasz Figa <t.figa at samsung.com>
>
> Due to recent consolidation of Exynos suspend and cpuidle code, some
> parts of suspend and resume sequences are executed two times, once from
> exynos_pm_syscore_ops and then from exynos_cpu_pm_notifier() and thus it
> breaks suspend, at least on Exynos4-based boards. In addition, simple
> core power down from a cpuidle driver could, in case of CPU 0 could
> result in calling functions that are specific to suspend and deeper idle
> states.
>
> This patch fixes the issue by moving those operations outside the CPU PM
> notifier into suspend and AFTR code paths. This leads to a bit of code
> duplication, but allows additional code simplification, so in the end
> more code is removed than added.
>
> Fixes: 85f9f90808b4 ("ARM: EXYNOS: Use the cpu_pm notifier for pm")
> Cc: Kukjin Kim <kgene.kim at samsung.com>
> Cc: Arnd Bergmann <arnd at arndb.de>
> Cc: Olof Johansson <olof at lixom.net>
> Cc: arm at kernel.org
> Signed-off-by: Tomasz Figa <t.figa at samsung.com>
> ---
> arch/arm/mach-exynos/pm.c | 164 ++++++++++++++++++---------------------
> drivers/cpuidle/cpuidle-exynos.c | 25 +-----
> 2 files changed, 80 insertions(+), 109 deletions(-)
>
> This is resend of a regression fix sent more than two weeks ago (July, 15;
> [1]), without any response from respective maintainers. It fixes
> a significant regression breaking suspend/resume on Exynos4-based systems.
>
> I know we already have -rc7, but this patch in its first iteration was
> sent more than a month ago (June, 24; [2]) and it changed only for
> convenience of authors of further patches, to either avoid conflicts ([3])
> or reduce the need of changes to support more functionality later (as
> discussed in [4]). However it should have had priority over clean-up or
> functional patches, which was apparently not the case.
This is not quite right, your initial version needed to be changed also
because of potential problems (https://lkml.org/lkml/2014/7/15/206).
However the current version (from two weeks ago) is fine and IMO still
should be merged as a _regression_ fix for v3.16 (despite not being
a tiny patch).
Also FWIW:
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie at samsung.com>
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
> [1] https://lkml.org/lkml/2014/7/15/319
> [2] https://lkml.org/lkml/2014/6/24/290
> [3] https://lkml.org/lkml/2014/6/24/351
> [4] http://thread.gmane.org/gmane.linux.kernel.samsung-soc/29085/focus=33975
>
> diff --git a/arch/arm/mach-exynos/pm.c b/arch/arm/mach-exynos/pm.c
> index 202ca73e49c4..e3b04b45f39b 100644
> --- a/arch/arm/mach-exynos/pm.c
> +++ b/arch/arm/mach-exynos/pm.c
> @@ -176,26 +176,6 @@ int exynos_cluster_power_state(int cluster)
> #define S5P_CHECK_AFTR 0xFCBA0D10
> #define S5P_CHECK_SLEEP 0x00000BAD
>
> -/* Ext-GIC nIRQ/nFIQ is the only wakeup source in AFTR */
> -static void exynos_set_wakeupmask(long mask)
> -{
> - __raw_writel(mask, S5P_WAKEUP_MASK);
> -}
> -
> -static void exynos_cpu_set_boot_vector(long flags)
> -{
> - __raw_writel(virt_to_phys(exynos_cpu_resume), EXYNOS_BOOT_VECTOR_ADDR);
> - __raw_writel(flags, EXYNOS_BOOT_VECTOR_FLAG);
> -}
> -
> -void exynos_enter_aftr(void)
> -{
> - exynos_set_wakeupmask(0x0000ff3e);
> - exynos_cpu_set_boot_vector(S5P_CHECK_AFTR);
> - /* Set value of power down register for aftr mode */
> - exynos_sys_powerdown_conf(SYS_AFTR);
> -}
> -
> /* For Cortex-A9 Diagnostic and Power control register */
> static unsigned int save_arm_register[2];
>
> @@ -235,6 +215,82 @@ static void exynos_cpu_restore_register(void)
> : "cc");
> }
>
> +static void exynos_pm_central_suspend(void)
> +{
> + unsigned long tmp;
> +
> + /* Setting Central Sequence Register for power down mode */
> + tmp = __raw_readl(S5P_CENTRAL_SEQ_CONFIGURATION);
> + tmp &= ~S5P_CENTRAL_LOWPWR_CFG;
> + __raw_writel(tmp, S5P_CENTRAL_SEQ_CONFIGURATION);
> +}
> +
> +static int exynos_pm_central_resume(void)
> +{
> + unsigned long tmp;
> +
> + /*
> + * If PMU failed while entering sleep mode, WFI will be
> + * ignored by PMU and then exiting cpu_do_idle().
> + * S5P_CENTRAL_LOWPWR_CFG bit will not be set automatically
> + * in this situation.
> + */
> + tmp = __raw_readl(S5P_CENTRAL_SEQ_CONFIGURATION);
> + if (!(tmp & S5P_CENTRAL_LOWPWR_CFG)) {
> + tmp |= S5P_CENTRAL_LOWPWR_CFG;
> + __raw_writel(tmp, S5P_CENTRAL_SEQ_CONFIGURATION);
> + /* clear the wakeup state register */
> + __raw_writel(0x0, S5P_WAKEUP_STAT);
> + /* No need to perform below restore code */
> + return -1;
> + }
> +
> + return 0;
> +}
> +
> +/* Ext-GIC nIRQ/nFIQ is the only wakeup source in AFTR */
> +static void exynos_set_wakeupmask(long mask)
> +{
> + __raw_writel(mask, S5P_WAKEUP_MASK);
> +}
> +
> +static void exynos_cpu_set_boot_vector(long flags)
> +{
> + __raw_writel(virt_to_phys(exynos_cpu_resume), EXYNOS_BOOT_VECTOR_ADDR);
> + __raw_writel(flags, EXYNOS_BOOT_VECTOR_FLAG);
> +}
> +
> +static int exynos_aftr_finisher(unsigned long flags)
> +{
> + exynos_set_wakeupmask(0x0000ff3e);
> + exynos_cpu_set_boot_vector(S5P_CHECK_AFTR);
> + /* Set value of power down register for aftr mode */
> + exynos_sys_powerdown_conf(SYS_AFTR);
> + cpu_do_idle();
> +
> + return 0;
> +}
> +
> +void exynos_enter_aftr(void)
> +{
> + cpu_pm_enter();
> +
> + exynos_pm_central_suspend();
> + if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9)
> + exynos_cpu_save_register();
> +
> + cpu_suspend(0, exynos_aftr_finisher);
> +
> + if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9) {
> + scu_enable(S5P_VA_SCU);
> + exynos_cpu_restore_register();
> + }
> +
> + exynos_pm_central_resume();
> +
> + cpu_pm_exit();
> +}
> +
> static int exynos_cpu_suspend(unsigned long arg)
> {
> #ifdef CONFIG_CACHE_L2X0
> @@ -279,16 +335,6 @@ static void exynos_pm_prepare(void)
> __raw_writel(virt_to_phys(exynos_cpu_resume), S5P_INFORM0);
> }
>
> -static void exynos_pm_central_suspend(void)
> -{
> - unsigned long tmp;
> -
> - /* Setting Central Sequence Register for power down mode */
> - tmp = __raw_readl(S5P_CENTRAL_SEQ_CONFIGURATION);
> - tmp &= ~S5P_CENTRAL_LOWPWR_CFG;
> - __raw_writel(tmp, S5P_CENTRAL_SEQ_CONFIGURATION);
> -}
> -
> static int exynos_pm_suspend(void)
> {
> unsigned long tmp;
> @@ -306,29 +352,6 @@ static int exynos_pm_suspend(void)
> return 0;
> }
>
> -static int exynos_pm_central_resume(void)
> -{
> - unsigned long tmp;
> -
> - /*
> - * If PMU failed while entering sleep mode, WFI will be
> - * ignored by PMU and then exiting cpu_do_idle().
> - * S5P_CENTRAL_LOWPWR_CFG bit will not be set automatically
> - * in this situation.
> - */
> - tmp = __raw_readl(S5P_CENTRAL_SEQ_CONFIGURATION);
> - if (!(tmp & S5P_CENTRAL_LOWPWR_CFG)) {
> - tmp |= S5P_CENTRAL_LOWPWR_CFG;
> - __raw_writel(tmp, S5P_CENTRAL_SEQ_CONFIGURATION);
> - /* clear the wakeup state register */
> - __raw_writel(0x0, S5P_WAKEUP_STAT);
> - /* No need to perform below restore code */
> - return -1;
> - }
> -
> - return 0;
> -}
> -
> static void exynos_pm_resume(void)
> {
> if (exynos_pm_central_resume())
> @@ -431,45 +454,10 @@ static const struct platform_suspend_ops exynos_suspend_ops = {
> .valid = suspend_valid_only_mem,
> };
>
> -static int exynos_cpu_pm_notifier(struct notifier_block *self,
> - unsigned long cmd, void *v)
> -{
> - int cpu = smp_processor_id();
> -
> - switch (cmd) {
> - case CPU_PM_ENTER:
> - if (cpu == 0) {
> - exynos_pm_central_suspend();
> - if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9)
> - exynos_cpu_save_register();
> - }
> - break;
> -
> - case CPU_PM_EXIT:
> - if (cpu == 0) {
> - if (read_cpuid_part_number() ==
> - ARM_CPU_PART_CORTEX_A9) {
> - scu_enable(S5P_VA_SCU);
> - exynos_cpu_restore_register();
> - }
> - exynos_pm_central_resume();
> - }
> - break;
> - }
> -
> - return NOTIFY_OK;
> -}
> -
> -static struct notifier_block exynos_cpu_pm_notifier_block = {
> - .notifier_call = exynos_cpu_pm_notifier,
> -};
> -
> void __init exynos_pm_init(void)
> {
> u32 tmp;
>
> - cpu_pm_register_notifier(&exynos_cpu_pm_notifier_block);
> -
> /* Platform-specific GIC callback */
> gic_arch_extn.irq_set_wake = exynos_irq_set_wake;
>
> diff --git a/drivers/cpuidle/cpuidle-exynos.c b/drivers/cpuidle/cpuidle-exynos.c
> index 7c0151263828..ba9b34b579f3 100644
> --- a/drivers/cpuidle/cpuidle-exynos.c
> +++ b/drivers/cpuidle/cpuidle-exynos.c
> @@ -20,25 +20,6 @@
>
> static void (*exynos_enter_aftr)(void);
>
> -static int idle_finisher(unsigned long flags)
> -{
> - exynos_enter_aftr();
> - cpu_do_idle();
> -
> - return 1;
> -}
> -
> -static int exynos_enter_core0_aftr(struct cpuidle_device *dev,
> - struct cpuidle_driver *drv,
> - int index)
> -{
> - cpu_pm_enter();
> - cpu_suspend(0, idle_finisher);
> - cpu_pm_exit();
> -
> - return index;
> -}
> -
> static int exynos_enter_lowpower(struct cpuidle_device *dev,
> struct cpuidle_driver *drv,
> int index)
> @@ -51,8 +32,10 @@ static int exynos_enter_lowpower(struct cpuidle_device *dev,
>
> if (new_index == 0)
> return arm_cpuidle_simple_enter(dev, drv, new_index);
> - else
> - return exynos_enter_core0_aftr(dev, drv, new_index);
> +
> + exynos_enter_aftr();
> +
> + return new_index;
> }
>
> static struct cpuidle_driver exynos_idle_driver = {
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