diff options
Diffstat (limited to 'arch/xtensa/kernel/time.c')
| -rw-r--r-- | arch/xtensa/kernel/time.c | 161 |
1 files changed, 105 insertions, 56 deletions
diff --git a/arch/xtensa/kernel/time.c b/arch/xtensa/kernel/time.c index 19df764f639..2a1823de69c 100644 --- a/arch/xtensa/kernel/time.c +++ b/arch/xtensa/kernel/time.c @@ -16,114 +16,163 @@ #include <linux/sched.h> #include <linux/time.h> #include <linux/clocksource.h> +#include <linux/clockchips.h> #include <linux/interrupt.h> #include <linux/module.h> #include <linux/init.h> #include <linux/irq.h> #include <linux/profile.h> #include <linux/delay.h> +#include <linux/irqdomain.h> +#include <linux/sched_clock.h> #include <asm/timex.h> #include <asm/platform.h> -#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT -unsigned long ccount_per_jiffy; /* per 1/HZ */ -unsigned long nsec_per_ccount; /* nsec per ccount increment */ -#endif +unsigned long ccount_freq; /* ccount Hz */ +EXPORT_SYMBOL(ccount_freq); -static cycle_t ccount_read(void) +static cycle_t ccount_read(struct clocksource *cs) { return (cycle_t)get_ccount(); } +static u64 notrace ccount_sched_clock_read(void) +{ + return get_ccount(); +} + static struct clocksource ccount_clocksource = { .name = "ccount", .rating = 200, .read = ccount_read, .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static int ccount_timer_set_next_event(unsigned long delta, + struct clock_event_device *dev); +static void ccount_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt); +struct ccount_timer { + struct clock_event_device evt; + int irq_enabled; + char name[24]; +}; +static DEFINE_PER_CPU(struct ccount_timer, ccount_timer); + +static int ccount_timer_set_next_event(unsigned long delta, + struct clock_event_device *dev) +{ + unsigned long flags, next; + int ret = 0; + + local_irq_save(flags); + next = get_ccount() + delta; + set_linux_timer(next); + if (next - get_ccount() > delta) + ret = -ETIME; + local_irq_restore(flags); + + return ret; +} + +static void ccount_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + struct ccount_timer *timer = + container_of(evt, struct ccount_timer, evt); + /* - * With a shift of 22 the lower limit of the cpu clock is - * 1MHz, where NSEC_PER_CCOUNT is 1000 or a bit less than - * 2^10: Since we have 32 bits and the multiplicator can - * already take up as much as 10 bits, this leaves us with - * remaining upper 22 bits. + * There is no way to disable the timer interrupt at the device level, + * only at the intenable register itself. Since enable_irq/disable_irq + * calls are nested, we need to make sure that these calls are + * balanced. */ - .shift = 22, -}; + switch (mode) { + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_UNUSED: + if (timer->irq_enabled) { + disable_irq(evt->irq); + timer->irq_enabled = 0; + } + break; + case CLOCK_EVT_MODE_RESUME: + case CLOCK_EVT_MODE_ONESHOT: + if (!timer->irq_enabled) { + enable_irq(evt->irq); + timer->irq_enabled = 1; + } + default: + break; + } +} static irqreturn_t timer_interrupt(int irq, void *dev_id); static struct irqaction timer_irqaction = { .handler = timer_interrupt, - .flags = IRQF_DISABLED, + .flags = IRQF_TIMER, .name = "timer", }; +void local_timer_setup(unsigned cpu) +{ + struct ccount_timer *timer = &per_cpu(ccount_timer, cpu); + struct clock_event_device *clockevent = &timer->evt; + + timer->irq_enabled = 1; + clockevent->name = timer->name; + snprintf(timer->name, sizeof(timer->name), "ccount_clockevent_%u", cpu); + clockevent->features = CLOCK_EVT_FEAT_ONESHOT; + clockevent->rating = 300; + clockevent->set_next_event = ccount_timer_set_next_event; + clockevent->set_mode = ccount_timer_set_mode; + clockevent->cpumask = cpumask_of(cpu); + clockevent->irq = irq_create_mapping(NULL, LINUX_TIMER_INT); + if (WARN(!clockevent->irq, "error: can't map timer irq")) + return; + clockevents_config_and_register(clockevent, ccount_freq, + 0xf, 0xffffffff); +} + void __init time_init(void) { #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT printk("Calibrating CPU frequency "); platform_calibrate_ccount(); - printk("%d.%02d MHz\n", (int)ccount_per_jiffy/(1000000/HZ), - (int)(ccount_per_jiffy/(10000/HZ))%100); + printk("%d.%02d MHz\n", (int)ccount_freq/1000000, + (int)(ccount_freq/10000)%100); +#else + ccount_freq = CONFIG_XTENSA_CPU_CLOCK*1000000UL; #endif - ccount_clocksource.mult = - clocksource_hz2mult(CCOUNT_PER_JIFFY * HZ, - ccount_clocksource.shift); - clocksource_register(&ccount_clocksource); - - /* Initialize the linux timer interrupt. */ - - setup_irq(LINUX_TIMER_INT, &timer_irqaction); - set_linux_timer(get_ccount() + CCOUNT_PER_JIFFY); + clocksource_register_hz(&ccount_clocksource, ccount_freq); + local_timer_setup(0); + setup_irq(this_cpu_ptr(&ccount_timer)->evt.irq, &timer_irqaction); + sched_clock_register(ccount_sched_clock_read, 32, ccount_freq); + clocksource_of_init(); } /* * The timer interrupt is called HZ times per second. */ -irqreturn_t timer_interrupt (int irq, void *dev_id) +irqreturn_t timer_interrupt(int irq, void *dev_id) { + struct clock_event_device *evt = &this_cpu_ptr(&ccount_timer)->evt; - unsigned long next; - - next = get_linux_timer(); - -again: - while ((signed long)(get_ccount() - next) > 0) { - - profile_tick(CPU_PROFILING); -#ifndef CONFIG_SMP - update_process_times(user_mode(get_irq_regs())); -#endif - - write_seqlock(&xtime_lock); - - do_timer(1); /* Linux handler in kernel/timer.c */ - - /* Note that writing CCOMPARE clears the interrupt. */ - - next += CCOUNT_PER_JIFFY; - set_linux_timer(next); - - write_sequnlock(&xtime_lock); - } + set_linux_timer(get_linux_timer()); + evt->event_handler(evt); /* Allow platform to do something useful (Wdog). */ - platform_heartbeat(); - /* Make sure we didn't miss any tick... */ - - if ((signed long)(get_ccount() - next) > 0) - goto again; - return IRQ_HANDLED; } #ifndef CONFIG_GENERIC_CALIBRATE_DELAY -void __cpuinit calibrate_delay(void) +void calibrate_delay(void) { - loops_per_jiffy = CCOUNT_PER_JIFFY; + loops_per_jiffy = ccount_freq / HZ; printk("Calibrating delay loop (skipped)... " "%lu.%02lu BogoMIPS preset\n", loops_per_jiffy/(1000000/HZ), |