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[ARM] 2862/1: VST aka CONFIG_NO_IDLE_HZ support for PXA2xx

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Patch from Nicolas Pitre

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Nicolas Pitre
2005-09-01 12:48:40 +01:00
committed by Russell King
parent 68d9102f76
commit 5c53ff088c
2 changed files with 53 additions and 2 deletions
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51
arch/arm/mach-pxa/time.c
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@@ -70,6 +70,11 @@ static unsigned long pxa_gettimeoffset (void)
return usec;
}
#ifdef CONFIG_NO_IDLE_HZ
static unsigned long initial_match;
static int match_posponed;
#endif
static irqreturn_t
pxa_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
@@ -77,6 +82,13 @@ pxa_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
write_seqlock(&xtime_lock);
#ifdef CONFIG_NO_IDLE_HZ
if (match_posponed) {
match_posponed = 0;
OSMR0 = initial_match;
}
#endif
/* Loop until we get ahead of the free running timer.
* This ensures an exact clock tick count and time accuracy.
* IRQs are disabled inside the loop to ensure coherence between
@@ -126,6 +138,42 @@ static void __init pxa_timer_init(void)
OSCR = 0; /* initialize free-running timer, force first match */
}
#ifdef CONFIG_NO_IDLE_HZ
static int pxa_dyn_tick_enable_disable(void)
{
/* nothing to do */
return 0;
}
static void pxa_dyn_tick_reprogram(unsigned long ticks)
{
if (ticks > 1) {
initial_match = OSMR0;
OSMR0 = initial_match + ticks * LATCH;
match_posponed = 1;
}
}
static irqreturn_t
pxa_dyn_tick_handler(int irq, void *dev_id, struct pt_regs *regs)
{
if (match_posponed) {
match_posponed = 0;
OSMR0 = initial_match;
if ( (signed long)(initial_match - OSCR) <= 8 )
return pxa_timer_interrupt(irq, dev_id, regs);
}
return IRQ_NONE;
}
static struct dyn_tick_timer pxa_dyn_tick = {
.enable = pxa_dyn_tick_enable_disable,
.disable = pxa_dyn_tick_enable_disable,
.reprogram = pxa_dyn_tick_reprogram,
.handler = pxa_dyn_tick_handler,
};
#endif
#ifdef CONFIG_PM
static unsigned long osmr[4], oier;
@@ -161,4 +209,7 @@ struct sys_timer pxa_timer = {
.suspend = pxa_timer_suspend,
.resume = pxa_timer_resume,
.offset = pxa_gettimeoffset,
#ifdef CONFIG_NO_IDLE_HZ
.dyn_tick = &pxa_dyn_tick,
#endif
};