From 2ea83398b75309d8fdc999c4bb252e72d7e4fd9d Mon Sep 17 00:00:00 2001
From: Russell King <rmk@dyn-67.arm.linux.org.uk>
Date: Mon, 27 Jun 2005 14:04:05 +0100
Subject: [PATCH] [PATCH] ARM: Add VST idle loop call
This call allows the dynamic tick support to reprogram the timer
immediately before the CPU idles.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
arch/arm/kernel/process.c | 5 ++++-
arch/arm/kernel/time.c | 10 +++++++---
include/asm-arm/mach/time.h | 2 ++
3 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 8f146a4b4752..bbea636ff687 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -32,6 +32,7 @@
#include <asm/leds.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
+#include <asm/mach/time.h>
extern const char *processor_modes[];
extern void setup_mm_for_reboot(char mode);
@@ -85,8 +86,10 @@ EXPORT_SYMBOL(pm_power_off);
void default_idle(void)
{
local_irq_disable();
- if (!need_resched() && !hlt_counter)
+ if (!need_resched() && !hlt_counter) {
+ timer_dyn_reprogram();
arch_idle();
+ }
local_irq_enable();
}
diff --git a/arch/arm/kernel/time.c b/arch/arm/kernel/time.c
index 06054c9ba074..1b7fcd50c3e2 100644
--- a/arch/arm/kernel/time.c
+++ b/arch/arm/kernel/time.c
@@ -424,15 +424,19 @@ static int timer_dyn_tick_disable(void)
return ret;
}
+/*
+ * Reprogram the system timer for at least the calculated time interval.
+ * This function should be called from the idle thread with IRQs disabled,
+ * immediately before sleeping.
+ */
void timer_dyn_reprogram(void)
{
struct dyn_tick_timer *dyn_tick = system_timer->dyn_tick;
- unsigned long flags;
- write_seqlock_irqsave(&xtime_lock, flags);
+ write_seqlock(&xtime_lock);
if (dyn_tick->state & DYN_TICK_ENABLED)
dyn_tick->reprogram(next_timer_interrupt() - jiffies);
- write_sequnlock_irqrestore(&xtime_lock, flags);
+ write_sequnlock(&xtime_lock);
}
static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
diff --git a/include/asm-arm/mach/time.h b/include/asm-arm/mach/time.h
index 047980ad18d1..2cf279a44017 100644
--- a/include/asm-arm/mach/time.h
+++ b/include/asm-arm/mach/time.h
@@ -60,6 +60,8 @@ struct dyn_tick_timer {
};
void timer_dyn_reprogram(void);
+#else
+#define timer_dyn_reprogram() do { } while (0)
#endif
extern struct sys_timer *system_timer;