diff options
| -rw-r--r-- | arch/arm/Kconfig | 4 | ||||
| -rw-r--r-- | arch/arm/mach-pxa/time.c | 51 |
2 files changed, 53 insertions, 2 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 4bf0e8737e1..dc0fafc7f9b 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -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 diff --git a/arch/arm/mach-pxa/time.c b/arch/arm/mach-pxa/time.c index 6e5202154f9..72b15e9a373 100644 --- a/arch/arm/mach-pxa/time.c +++ b/arch/arm/mach-pxa/time.c @@ -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 }; |