Commit 4fa20439 authored by Nicolas Pitre's avatar Nicolas Pitre Committed by Nicolas Pitre
Browse files

ARM: clean up idle handlers 



Let's factor out the need_resched() check instead of having it duplicated
in every pm_idle implementations to avoid inconsistencies (omap2_pm_idle
is missing it already).

The forceful re-enablement of IRQs after pm_idle has returned can go.
The warning certainly doesn't trigger for existing users.

To get rid of the pm_idle calling convention oddity, let's introduce
arm_pm_idle() allowing for the local_irq_enable() to be factored out
from SOC specific implementations. The default pm_idle function becomes
a wrapper for arm_pm_idle and it takes care of enabling IRQs closer to
where they are initially disabled.

And finally move the comment explaining the reason for that turning off
of IRQs to a more proper location.

Signed-off-by: default avatarNicolas Pitre <nicolas.pitre@linaro.org>
Acked-and-tested-by: default avatarJamie Iles <jamie@jamieiles.com>
parent 3c0b2cef

arch/arm/include/asm/system.h

+1 −0
Original line number Diff line number Diff line
@@ -110,6 +110,7 @@ extern void cpu_init(void); 


void soft_restart(unsigned long);

extern void (*arm_pm_restart)(char str, const char *cmd);

extern void (*arm_pm_idle)(void);



#define UDBG_UNDEFINED	(1 << 0)

#define UDBG_SYSCALL	(1 << 1)

arch/arm/kernel/process.c

+15 −8
Original line number Diff line number Diff line
@@ -181,12 +181,16 @@ void cpu_idle_wait(void) 
EXPORT_SYMBOL_GPL(cpu_idle_wait);



/*

 * This is our default idle handler.  We need to disable

 * interrupts here to ensure we don't miss a wakeup call.

 * This is our default idle handler.

 */



void (*arm_pm_idle)(void);



static void default_idle(void)

{

	if (!need_resched())

	if (arm_pm_idle)

		arm_pm_idle();

	else

		arch_idle();

	local_irq_enable();

}
@@ -215,6 +219,10 @@ void cpu_idle(void) 
				cpu_die();

#endif



			/*

			 * We need to disable interrupts here

			 * to ensure we don't miss a wakeup call.

			 */

			local_irq_disable();

#ifdef CONFIG_PL310_ERRATA_769419

			wmb();
@@ -222,20 +230,19 @@ void cpu_idle(void) 
			if (hlt_counter) {

				local_irq_enable();

				cpu_relax();

			} else {

			} else if (!need_resched()) {

				stop_critical_timings();

				if (cpuidle_idle_call())

					pm_idle();

				start_critical_timings();

				/*

				 * This will eventually be removed - pm_idle

				 * functions should always return with IRQs

				 * enabled.

				 * pm_idle functions must always

				 * return with IRQs enabled.

				 */

				WARN_ON(irqs_disabled());

			} else

				local_irq_enable();

		}

		}

		leds_event(led_idle_end);

		rcu_idle_exit();

		tick_nohz_idle_exit();

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