Skip to content

Commit

Permalink
ARM: clean up idle handlers
Browse files Browse the repository at this point in the history
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: Nicolas Pitre <nicolas.pitre@linaro.org>
Acked-and-tested-by: Jamie Iles <jamie@jamieiles.com>
  • Loading branch information
Nicolas Pitre authored and Nicolas Pitre committed Jan 20, 2012
1 parent 3c0b2ce commit 4fa2043
Showing 2 changed files with 16 additions and 8 deletions.
1 change: 1 addition & 0 deletions arch/arm/include/asm/system.h
Original file line number Diff line number Diff line change
@@ -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)
23 changes: 15 additions & 8 deletions arch/arm/kernel/process.c
Original file line number Diff line number Diff line change
@@ -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();
}
@@ -215,26 +219,29 @@ 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();
#endif
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();

0 comments on commit 4fa2043

Please sign in to comment.