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yaml
---
r: 6805
b: refs/heads/master
c: 5c53ff0
h: refs/heads/master
i:
  6803: dcfc543
v: v3
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Nicolas Pitre authored and Russell King committed Sep 1, 2005
1 parent 942dd4e commit 5ba1964
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Showing 3 changed files with 54 additions and 3 deletions.
2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 68d9102f76de7a923fb81c8b6de4764f8f50ed17
refs/heads/master: 5c53ff088cb76dca52bdf2ef36ea63147763f9ea
4 changes: 2 additions & 2 deletions trunk/arch/arm/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -365,8 +365,8 @@ config NO_IDLE_HZ

Please note that dynamic tick may affect the accuracy of
timekeeping on some platforms depending on the implementation.
Currently at least OMAP platform is known to have accurate
timekeeping with dynamic tick.
Currently at least OMAP and PXA2xx platforms are known to have
accurate timekeeping with dynamic tick.

config ARCH_DISCONTIGMEM_ENABLE
bool
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51 changes: 51 additions & 0 deletions trunk/arch/arm/mach-pxa/time.c
Original file line number Diff line number Diff line change
Expand Up @@ -70,13 +70,25 @@ 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)
{
int next_match;

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
Expand Down Expand Up @@ -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;

Expand Down Expand Up @@ -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
};

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