diff options
Diffstat (limited to 'arch/arm/mach-pxa/time.c')
| -rw-r--r-- | arch/arm/mach-pxa/time.c | 79 |
1 files changed, 68 insertions, 11 deletions
diff --git a/arch/arm/mach-pxa/time.c b/arch/arm/mach-pxa/time.c index 98d27e646b0..fbfa1920353 100644 --- a/arch/arm/mach-pxa/time.c +++ b/arch/arm/mach-pxa/time.c @@ -16,10 +16,48 @@ #include <linux/init.h> #include <linux/interrupt.h> #include <linux/clockchips.h> +#include <linux/sched.h> +#include <asm/div64.h> +#include <asm/cnt32_to_63.h> #include <asm/mach/irq.h> #include <asm/mach/time.h> #include <asm/arch/pxa-regs.h> +#include <asm/mach-types.h> + +/* + * This is PXA's sched_clock implementation. This has a resolution + * of at least 308 ns and a maximum value of 208 days. + * + * The return value is guaranteed to be monotonic in that range as + * long as there is always less than 582 seconds between successive + * calls to sched_clock() which should always be the case in practice. + */ + +#define OSCR2NS_SCALE_FACTOR 10 + +static unsigned long oscr2ns_scale; + +static void __init set_oscr2ns_scale(unsigned long oscr_rate) +{ + unsigned long long v = 1000000000ULL << OSCR2NS_SCALE_FACTOR; + do_div(v, oscr_rate); + oscr2ns_scale = v; + /* + * We want an even value to automatically clear the top bit + * returned by cnt32_to_63() without an additional run time + * instruction. So if the LSB is 1 then round it up. + */ + if (oscr2ns_scale & 1) + oscr2ns_scale++; +} + +unsigned long long sched_clock(void) +{ + unsigned long long v = cnt32_to_63(OSCR); + return (v * oscr2ns_scale) >> OSCR2NS_SCALE_FACTOR; +} + static irqreturn_t pxa_ost0_interrupt(int irq, void *dev_id) @@ -30,6 +68,7 @@ pxa_ost0_interrupt(int irq, void *dev_id) if (c->mode == CLOCK_EVT_MODE_ONESHOT) { /* Disarm the compare/match, signal the event. */ OIER &= ~OIER_E0; + OSSR = OSSR_M0; c->event_handler(c); } else if (c->mode == CLOCK_EVT_MODE_PERIODIC) { /* Call the event handler as many times as necessary @@ -62,9 +101,9 @@ pxa_ost0_interrupt(int irq, void *dev_id) * anything that might put us "very close". */ #define MIN_OSCR_DELTA 16 - do { + do { OSSR = OSSR_M0; - next_match = (OSMR0 += LATCH); + next_match = (OSMR0 += LATCH); c->event_handler(c); } while (((signed long)(next_match - OSCR) <= MIN_OSCR_DELTA) && (c->mode == CLOCK_EVT_MODE_PERIODIC)); @@ -76,14 +115,16 @@ pxa_ost0_interrupt(int irq, void *dev_id) static int pxa_osmr0_set_next_event(unsigned long delta, struct clock_event_device *dev) { - unsigned long irqflags; + unsigned long flags, next, oscr; - raw_local_irq_save(irqflags); - OSMR0 = OSCR + delta; - OSSR = OSSR_M0; + raw_local_irq_save(flags); OIER |= OIER_E0; - raw_local_irq_restore(irqflags); - return 0; + next = OSCR + delta; + OSMR0 = next; + oscr = OSCR; + raw_local_irq_restore(flags); + + return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0; } static void @@ -94,15 +135,16 @@ pxa_osmr0_set_mode(enum clock_event_mode mode, struct clock_event_device *dev) switch (mode) { case CLOCK_EVT_MODE_PERIODIC: raw_local_irq_save(irqflags); - OSMR0 = OSCR + LATCH; OSSR = OSSR_M0; OIER |= OIER_E0; + OSMR0 = OSCR + LATCH; raw_local_irq_restore(irqflags); break; case CLOCK_EVT_MODE_ONESHOT: raw_local_irq_save(irqflags); OIER &= ~OIER_E0; + OSSR = OSSR_M0; raw_local_irq_restore(irqflags); break; @@ -111,8 +153,12 @@ pxa_osmr0_set_mode(enum clock_event_mode mode, struct clock_event_device *dev) /* initializing, released, or preparing for suspend */ raw_local_irq_save(irqflags); OIER &= ~OIER_E0; + OSSR = OSSR_M0; raw_local_irq_restore(irqflags); break; + + case CLOCK_EVT_MODE_RESUME: + break; } } @@ -149,18 +195,29 @@ static struct irqaction pxa_ost0_irq = { static void __init pxa_timer_init(void) { + unsigned long clock_tick_rate; + OIER = 0; OSSR = OSSR_M0 | OSSR_M1 | OSSR_M2 | OSSR_M3; + if (cpu_is_pxa21x() || cpu_is_pxa25x()) + clock_tick_rate = 3686400; + else if (machine_is_mainstone()) + clock_tick_rate = 3249600; + else + clock_tick_rate = 3250000; + + set_oscr2ns_scale(clock_tick_rate); + ckevt_pxa_osmr0.mult = - div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC, ckevt_pxa_osmr0.shift); + div_sc(clock_tick_rate, NSEC_PER_SEC, ckevt_pxa_osmr0.shift); ckevt_pxa_osmr0.max_delta_ns = clockevent_delta2ns(0x7fffffff, &ckevt_pxa_osmr0); ckevt_pxa_osmr0.min_delta_ns = clockevent_delta2ns(MIN_OSCR_DELTA, &ckevt_pxa_osmr0) + 1; cksrc_pxa_oscr0.mult = - clocksource_hz2mult(CLOCK_TICK_RATE, cksrc_pxa_oscr0.shift); + clocksource_hz2mult(clock_tick_rate, cksrc_pxa_oscr0.shift); setup_irq(IRQ_OST0, &pxa_ost0_irq); |