From 9ccdac3662dbf3c75e8f8851a214bdf7d365a4bd Mon Sep 17 00:00:00 2001 From: Russell King Date: Mon, 22 Jun 2009 22:34:55 +0100 Subject: [PATCH] [ARM] idle: clean up pm_idle calling, obey hlt_counter pm_idle is used by infrastructure (eg, cpuidle) which expects architectures to call it in a certain way. Arrange for ARM to follow x86's lead on this and call pm_idle() with interrupts already disabled. However, we expect pm_idle() to enable interrupts before it returns. Also, OMAP wants to be able to disable hlt-ing, so allow hlt_counter to prevent all calls to pm_idle. Signed-off-by: Russell King --- arch/arm/kernel/process.c | 58 +++++++++++++++++++++------------------ 1 file changed, 32 insertions(+), 26 deletions(-) diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 56820cce91a..39196dff478 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -114,9 +114,6 @@ void arm_machine_restart(char mode, const char *cmd) /* * Function pointers to optional machine specific functions */ -void (*pm_idle)(void); -EXPORT_SYMBOL(pm_idle); - void (*pm_power_off)(void); EXPORT_SYMBOL(pm_power_off); @@ -130,20 +127,19 @@ EXPORT_SYMBOL_GPL(arm_pm_restart); */ static void default_idle(void) { - if (hlt_counter) - cpu_relax(); - else { - local_irq_disable(); - if (!need_resched()) - arch_idle(); - local_irq_enable(); - } + if (!need_resched()) + arch_idle(); + local_irq_enable(); } +void (*pm_idle)(void) = default_idle; +EXPORT_SYMBOL(pm_idle); + /* - * The idle thread. We try to conserve power, while trying to keep - * overall latency low. The architecture specific idle is passed - * a value to indicate the level of "idleness" of the system. + * The idle thread, has rather strange semantics for calling pm_idle, + * but this is what x86 does and we need to do the same, so that + * things like cpuidle get called in the same way. The only difference + * is that we always respect 'hlt_counter' to prevent low power idle. */ void cpu_idle(void) { @@ -151,21 +147,31 @@ void cpu_idle(void) /* endless idle loop with no priority at all */ while (1) { - void (*idle)(void) = pm_idle; - + tick_nohz_stop_sched_tick(1); + leds_event(led_idle_start); + while (!need_resched()) { #ifdef CONFIG_HOTPLUG_CPU - if (cpu_is_offline(smp_processor_id())) { - leds_event(led_idle_start); - cpu_die(); - } + if (cpu_is_offline(smp_processor_id())) + cpu_die(); #endif - if (!idle) - idle = default_idle; - leds_event(led_idle_start); - tick_nohz_stop_sched_tick(1); - while (!need_resched()) - idle(); + local_irq_disable(); + if (hlt_counter) { + local_irq_enable(); + cpu_relax(); + } else { + stop_critical_timings(); + pm_idle(); + start_critical_timings(); + /* + * This will eventually be removed - pm_idle + * functions should always return with IRQs + * enabled. + */ + WARN_ON(irqs_disabled()); + local_irq_enable(); + } + } leds_event(led_idle_end); tick_nohz_restart_sched_tick(); preempt_enable_no_resched(); -- 2.41.0