From ab0e08f15d23628dd8d50bf6ce1a935a8840c7dc Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 18 May 2011 21:33:43 +0000 Subject: [PATCH] x86: hpet: Cleanup the clockevents init and register code No need to recalculate the frequency and the conversion factors over and over. Calculate the frequency once and use the new config/register interface and let the core code do the math. Signed-off-by: Thomas Gleixner Cc: John Stultz Reviewed-by: Ingo Molnar Link: http://lkml.kernel.org/r/%3C20110518210136.646482357%40linutronix.de%3E --- arch/x86/kernel/hpet.c | 72 ++++++++++-------------------------------- 1 file changed, 16 insertions(+), 56 deletions(-) diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c index bfe8f729e086..6781765b3a0d 100644 --- a/arch/x86/kernel/hpet.c +++ b/arch/x86/kernel/hpet.c @@ -217,7 +217,7 @@ static void hpet_reserve_platform_timers(unsigned int id) { } /* * Common hpet info */ -static unsigned long hpet_period; +static unsigned long hpet_freq; static void hpet_legacy_set_mode(enum clock_event_mode mode, struct clock_event_device *evt); @@ -232,7 +232,6 @@ static struct clock_event_device hpet_clockevent = { .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, .set_mode = hpet_legacy_set_mode, .set_next_event = hpet_legacy_next_event, - .shift = 32, .irq = 0, .rating = 50, }; @@ -289,29 +288,13 @@ static void hpet_legacy_clockevent_register(void) /* Start HPET legacy interrupts */ hpet_enable_legacy_int(); - /* - * The mult factor is defined as (include/linux/clockchips.h) - * mult/2^shift = cyc/ns (in contrast to ns/cyc in clocksource.h) - * hpet_period is in units of femtoseconds (per cycle), so - * mult/2^shift = cyc/ns = 10^6/hpet_period - * mult = (10^6 * 2^shift)/hpet_period - * mult = (FSEC_PER_NSEC << hpet_clockevent.shift)/hpet_period - */ - hpet_clockevent.mult = div_sc((unsigned long) FSEC_PER_NSEC, - hpet_period, hpet_clockevent.shift); - /* Calculate the min / max delta */ - hpet_clockevent.max_delta_ns = clockevent_delta2ns(0x7FFFFFFF, - &hpet_clockevent); - /* Setup minimum reprogramming delta. */ - hpet_clockevent.min_delta_ns = clockevent_delta2ns(HPET_MIN_PROG_DELTA, - &hpet_clockevent); - /* * Start hpet with the boot cpu mask and make it * global after the IO_APIC has been initialized. */ hpet_clockevent.cpumask = cpumask_of(smp_processor_id()); - clockevents_register_device(&hpet_clockevent); + clockevents_config_and_register(&hpet_clockevent, hpet_freq, + HPET_MIN_PROG_DELTA, 0x7FFFFFFF); global_clock_event = &hpet_clockevent; printk(KERN_DEBUG "hpet clockevent registered\n"); } @@ -549,7 +532,6 @@ static int hpet_setup_irq(struct hpet_dev *dev) static void init_one_hpet_msi_clockevent(struct hpet_dev *hdev, int cpu) { struct clock_event_device *evt = &hdev->evt; - uint64_t hpet_freq; WARN_ON(cpu != smp_processor_id()); if (!(hdev->flags & HPET_DEV_VALID)) @@ -571,24 +553,10 @@ static void init_one_hpet_msi_clockevent(struct hpet_dev *hdev, int cpu) evt->set_mode = hpet_msi_set_mode; evt->set_next_event = hpet_msi_next_event; - evt->shift = 32; - - /* - * The period is a femto seconds value. We need to calculate the - * scaled math multiplication factor for nanosecond to hpet tick - * conversion. - */ - hpet_freq = FSEC_PER_SEC; - do_div(hpet_freq, hpet_period); - evt->mult = div_sc((unsigned long) hpet_freq, - NSEC_PER_SEC, evt->shift); - /* Calculate the max delta */ - evt->max_delta_ns = clockevent_delta2ns(0x7FFFFFFF, evt); - /* 5 usec minimum reprogramming delta. */ - evt->min_delta_ns = 5000; - evt->cpumask = cpumask_of(hdev->cpu); - clockevents_register_device(evt); + + clockevents_config_and_register(evt, hpet_freq, HPET_MIN_PROG_DELTA, + 0x7FFFFFFF); } #ifdef CONFIG_HPET @@ -792,7 +760,6 @@ static struct clocksource clocksource_hpet = { static int hpet_clocksource_register(void) { u64 start, now; - u64 hpet_freq; cycle_t t1; /* Start the counter */ @@ -819,24 +786,7 @@ static int hpet_clocksource_register(void) return -ENODEV; } - /* - * The definition of mult is (include/linux/clocksource.h) - * mult/2^shift = ns/cyc and hpet_period is in units of fsec/cyc - * so we first need to convert hpet_period to ns/cyc units: - * mult/2^shift = ns/cyc = hpet_period/10^6 - * mult = (hpet_period * 2^shift)/10^6 - * mult = (hpet_period << shift)/FSEC_PER_NSEC - */ - - /* Need to convert hpet_period (fsec/cyc) to cyc/sec: - * - * cyc/sec = FSEC_PER_SEC/hpet_period(fsec/cyc) - * cyc/sec = (FSEC_PER_NSEC * NSEC_PER_SEC)/hpet_period - */ - hpet_freq = FSEC_PER_SEC; - do_div(hpet_freq, hpet_period); clocksource_register_hz(&clocksource_hpet, (u32)hpet_freq); - return 0; } @@ -845,7 +795,9 @@ static int hpet_clocksource_register(void) */ int __init hpet_enable(void) { + unsigned long hpet_period; unsigned int id; + u64 freq; int i; if (!is_hpet_capable()) @@ -883,6 +835,14 @@ int __init hpet_enable(void) if (hpet_period < HPET_MIN_PERIOD || hpet_period > HPET_MAX_PERIOD) goto out_nohpet; + /* + * The period is a femto seconds value. Convert it to a + * frequency. + */ + freq = FSEC_PER_SEC; + do_div(freq, hpet_period); + hpet_freq = freq; + /* * Read the HPET ID register to retrieve the IRQ routing * information and the number of channels -- 2.20.1