diff options
Diffstat (limited to 'arch/x86_64/kernel/time.c')
| -rw-r--r-- | arch/x86_64/kernel/time.c | 664 |
1 files changed, 4 insertions, 660 deletions
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c index 76857add2f51..216fc9d74247 100644 --- a/arch/x86_64/kernel/time.c +++ b/arch/x86_64/kernel/time.c @@ -42,9 +42,10 @@ #include <linux/cpufreq.h> #include <linux/hpet.h> #include <asm/apic.h> +#include <asm/hpet.h> #ifdef CONFIG_CPU_FREQ -static void cpufreq_delayed_get(void); +extern void cpufreq_delayed_get(void); #endif extern void i8254_timer_resume(void); extern int using_apic_timer; @@ -55,22 +56,6 @@ DEFINE_SPINLOCK(rtc_lock); EXPORT_SYMBOL(rtc_lock); DEFINE_SPINLOCK(i8253_lock); -int nohpet __initdata = 0; -static int notsc __initdata = 0; - -#define USEC_PER_TICK (USEC_PER_SEC / HZ) -#define NSEC_PER_TICK (NSEC_PER_SEC / HZ) -#define FSEC_PER_TICK (FSEC_PER_SEC / HZ) - -#define NS_SCALE 10 /* 2^10, carefully chosen */ -#define US_SCALE 32 /* 2^32, arbitralrily chosen */ - -unsigned int cpu_khz; /* TSC clocks / usec, not used here */ -EXPORT_SYMBOL(cpu_khz); -unsigned long hpet_address; -static unsigned long hpet_period; /* fsecs / HPET clock */ -unsigned long hpet_tick; /* HPET clocks / interrupt */ -int hpet_use_timer; /* Use counter of hpet for time keeping, otherwise PIT */ unsigned long vxtime_hz = PIT_TICK_RATE; int report_lost_ticks; /* command line option */ unsigned long long monotonic_base; @@ -81,34 +66,6 @@ volatile unsigned long __jiffies __section_jiffies = INITIAL_JIFFIES; struct timespec __xtime __section_xtime; struct timezone __sys_tz __section_sys_tz; -/* - * do_gettimeoffset() returns microseconds since last timer interrupt was - * triggered by hardware. A memory read of HPET is slower than a register read - * of TSC, but much more reliable. It's also synchronized to the timer - * interrupt. Note that do_gettimeoffset() may return more than hpet_tick, if a - * timer interrupt has happened already, but vxtime.trigger wasn't updated yet. - * This is not a problem, because jiffies hasn't updated either. They are bound - * together by xtime_lock. - */ - -static inline unsigned int do_gettimeoffset_tsc(void) -{ - unsigned long t; - unsigned long x; - t = get_cycles_sync(); - if (t < vxtime.last_tsc) - t = vxtime.last_tsc; /* hack */ - x = ((t - vxtime.last_tsc) * vxtime.tsc_quot) >> US_SCALE; - return x; -} - -static inline unsigned int do_gettimeoffset_hpet(void) -{ - /* cap counter read to one tick to avoid inconsistencies */ - unsigned long counter = hpet_readl(HPET_COUNTER) - vxtime.last; - return (min(counter,hpet_tick) * vxtime.quot) >> US_SCALE; -} - unsigned int (*do_gettimeoffset)(void) = do_gettimeoffset_tsc; /* @@ -272,7 +229,7 @@ static void set_rtc_mmss(unsigned long nowtime) * Note: This function is required to return accurate * time even in the absence of multiple timer ticks. */ -static inline unsigned long long cycles_2_ns(unsigned long long cyc); +extern unsigned long long cycles_2_ns(unsigned long long cyc); unsigned long long monotonic_clock(void) { unsigned long seq; @@ -462,40 +419,6 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id) return IRQ_HANDLED; } -static unsigned int cyc2ns_scale __read_mostly; - -static inline void set_cyc2ns_scale(unsigned long cpu_khz) -{ - cyc2ns_scale = (NSEC_PER_MSEC << NS_SCALE) / cpu_khz; -} - -static inline unsigned long long cycles_2_ns(unsigned long long cyc) -{ - return (cyc * cyc2ns_scale) >> NS_SCALE; -} - -unsigned long long sched_clock(void) -{ - unsigned long a = 0; - -#if 0 - /* Don't do a HPET read here. Using TSC always is much faster - and HPET may not be mapped yet when the scheduler first runs. - Disadvantage is a small drift between CPUs in some configurations, - but that should be tolerable. */ - if (__vxtime.mode == VXTIME_HPET) - return (hpet_readl(HPET_COUNTER) * vxtime.quot) >> US_SCALE; -#endif - - /* Could do CPU core sync here. Opteron can execute rdtsc speculatively, - which means it is not completely exact and may not be monotonous between - CPUs. But the errors should be too small to matter for scheduling - purposes. */ - - rdtscll(a); - return cycles_2_ns(a); -} - static unsigned long get_cmos_time(void) { unsigned int year, mon, day, hour, min, sec; @@ -547,164 +470,6 @@ static unsigned long get_cmos_time(void) return mktime(year, mon, day, hour, min, sec); } -#ifdef CONFIG_CPU_FREQ - -/* Frequency scaling support. Adjust the TSC based timer when the cpu frequency - changes. - - RED-PEN: On SMP we assume all CPUs run with the same frequency. It's - not that important because current Opteron setups do not support - scaling on SMP anyroads. - - Should fix up last_tsc too. Currently gettimeofday in the - first tick after the change will be slightly wrong. */ - -#include <linux/workqueue.h> - -static unsigned int cpufreq_delayed_issched = 0; -static unsigned int cpufreq_init = 0; -static struct work_struct cpufreq_delayed_get_work; - -static void handle_cpufreq_delayed_get(struct work_struct *v) -{ - unsigned int cpu; - for_each_online_cpu(cpu) { - cpufreq_get(cpu); - } - cpufreq_delayed_issched = 0; -} - -/* if we notice lost ticks, schedule a call to cpufreq_get() as it tries - * to verify the CPU frequency the timing core thinks the CPU is running - * at is still correct. - */ -static void cpufreq_delayed_get(void) -{ - static int warned; - if (cpufreq_init && !cpufreq_delayed_issched) { - cpufreq_delayed_issched = 1; - if (!warned) { - warned = 1; - printk(KERN_DEBUG - "Losing some ticks... checking if CPU frequency changed.\n"); - } - schedule_work(&cpufreq_delayed_get_work); - } -} - -static unsigned int ref_freq = 0; -static unsigned long loops_per_jiffy_ref = 0; - -static unsigned long cpu_khz_ref = 0; - -static int time_cpufreq_notifier(struct notifier_block *nb, unsigned long val, - void *data) -{ - struct cpufreq_freqs *freq = data; - unsigned long *lpj, dummy; - - if (cpu_has(&cpu_data[freq->cpu], X86_FEATURE_CONSTANT_TSC)) - return 0; - - lpj = &dummy; - if (!(freq->flags & CPUFREQ_CONST_LOOPS)) -#ifdef CONFIG_SMP - lpj = &cpu_data[freq->cpu].loops_per_jiffy; -#else - lpj = &boot_cpu_data.loops_per_jiffy; -#endif - - if (!ref_freq) { - ref_freq = freq->old; - loops_per_jiffy_ref = *lpj; - cpu_khz_ref = cpu_khz; - } - if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) || - (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) || - (val == CPUFREQ_RESUMECHANGE)) { - *lpj = - cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new); - - cpu_khz = cpufreq_scale(cpu_khz_ref, ref_freq, freq->new); - if (!(freq->flags & CPUFREQ_CONST_LOOPS)) - vxtime.tsc_quot = (USEC_PER_MSEC << US_SCALE) / cpu_khz; - } - - set_cyc2ns_scale(cpu_khz_ref); - - return 0; -} - -static struct notifier_block time_cpufreq_notifier_block = { - .notifier_call = time_cpufreq_notifier -}; - -static int __init cpufreq_tsc(void) -{ - INIT_WORK(&cpufreq_delayed_get_work, handle_cpufreq_delayed_get); - if (!cpufreq_register_notifier(&time_cpufreq_notifier_block, - CPUFREQ_TRANSITION_NOTIFIER)) - cpufreq_init = 1; - return 0; -} - -core_initcall(cpufreq_tsc); - -#endif - -/* - * calibrate_tsc() calibrates the processor TSC in a very simple way, comparing - * it to the HPET timer of known frequency. - */ - -#define TICK_COUNT 100000000 -#define TICK_MIN 5000 -#define MAX_READ_RETRIES 5 - -/* - * Some platforms take periodic SMI interrupts with 5ms duration. Make sure none - * occurs between the reads of the hpet & TSC. - */ -static void __init read_hpet_tsc(int *hpet, int *tsc) -{ - int tsc1, tsc2, hpet1, retries = 0; - static int msg; - - do { - tsc1 = get_cycles_sync(); - hpet1 = hpet_readl(HPET_COUNTER); - tsc2 = get_cycles_sync(); - } while (tsc2 - tsc1 > TICK_MIN && retries++ < MAX_READ_RETRIES); - if (retries >= MAX_READ_RETRIES && !msg++) - printk(KERN_WARNING - "hpet.c: exceeded max retries to read HPET & TSC\n"); - *hpet = hpet1; - *tsc = tsc2; -} - - -static unsigned int __init hpet_calibrate_tsc(void) -{ - int tsc_start, hpet_start; - int tsc_now, hpet_now; - unsigned long flags; - - local_irq_save(flags); - local_irq_disable(); - - read_hpet_tsc(&hpet_start, &tsc_start); - - do { - local_irq_disable(); - read_hpet_tsc(&hpet_now, &tsc_now); - local_irq_restore(flags); - } while ((tsc_now - tsc_start) < TICK_COUNT && - (hpet_now - hpet_start) < TICK_COUNT); - - return (tsc_now - tsc_start) * 1000000000L - / ((hpet_now - hpet_start) * hpet_period / 1000); -} - /* * pit_calibrate_tsc() uses the speaker output (channel 2) of @@ -735,124 +500,6 @@ static unsigned int __init pit_calibrate_tsc(void) return (end - start) / 50; } -#ifdef CONFIG_HPET -static __init int late_hpet_init(void) -{ - struct hpet_data hd; - unsigned int ntimer; - - if (!hpet_address) - return 0; - - memset(&hd, 0, sizeof (hd)); - - ntimer = hpet_readl(HPET_ID); - ntimer = (ntimer & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT; - ntimer++; - - /* - * Register with driver. - * Timer0 and Timer1 is used by platform. - */ - hd.hd_phys_address = hpet_address; - hd.hd_address = (void __iomem *)fix_to_virt(FIX_HPET_BASE); - hd.hd_nirqs = ntimer; - hd.hd_flags = HPET_DATA_PLATFORM; - hpet_reserve_timer(&hd, 0); -#ifdef CONFIG_HPET_EMULATE_RTC - hpet_reserve_timer(&hd, 1); -#endif - hd.hd_irq[0] = HPET_LEGACY_8254; - hd.hd_irq[1] = HPET_LEGACY_RTC; - if (ntimer > 2) { - struct hpet *hpet; - struct hpet_timer *timer; - int i; - - hpet = (struct hpet *) fix_to_virt(FIX_HPET_BASE); - timer = &hpet->hpet_timers[2]; - for (i = 2; i < ntimer; timer++, i++) - hd.hd_irq[i] = (timer->hpet_config & - Tn_INT_ROUTE_CNF_MASK) >> - Tn_INT_ROUTE_CNF_SHIFT; - - } - - hpet_alloc(&hd); - return 0; -} -fs_initcall(late_hpet_init); -#endif - -static int hpet_timer_stop_set_go(unsigned long tick) -{ - unsigned int cfg; - -/* - * Stop the timers and reset the main counter. - */ - - cfg = hpet_readl(HPET_CFG); - cfg &= ~(HPET_CFG_ENABLE | HPET_CFG_LEGACY); - hpet_writel(cfg, HPET_CFG); - hpet_writel(0, HPET_COUNTER); - hpet_writel(0, HPET_COUNTER + 4); - -/* - * Set up timer 0, as periodic with first interrupt to happen at hpet_tick, - * and period also hpet_tick. - */ - if (hpet_use_timer) { - hpet_writel(HPET_TN_ENABLE | HPET_TN_PERIODIC | HPET_TN_SETVAL | - HPET_TN_32BIT, HPET_T0_CFG); - hpet_writel(hpet_tick, HPET_T0_CMP); /* next interrupt */ - hpet_writel(hpet_tick, HPET_T0_CMP); /* period */ - cfg |= HPET_CFG_LEGACY; - } -/* - * Go! - */ - - cfg |= HPET_CFG_ENABLE; - hpet_writel(cfg, HPET_CFG); - - return 0; -} - -static int hpet_init(void) -{ - unsigned int id; - - if (!hpet_address) - return -1; - set_fixmap_nocache(FIX_HPET_BASE, hpet_address); - __set_fixmap(VSYSCALL_HPET, hpet_address, PAGE_KERNEL_VSYSCALL_NOCACHE); - -/* - * Read the period, compute tick and quotient. - */ - - id = hpet_readl(HPET_ID); - - if (!(id & HPET_ID_VENDOR) || !(id & HPET_ID_NUMBER)) - return -1; - - hpet_period = hpet_readl(HPET_PERIOD); - if (hpet_period < 100000 || hpet_period > 100000000) - return -1; - - hpet_tick = (FSEC_PER_TICK + hpet_period / 2) / hpet_period; - - hpet_use_timer = (id & HPET_ID_LEGSUP); - - return hpet_timer_stop_set_go(hpet_tick); -} - -static int hpet_reenable(void) -{ - return hpet_timer_stop_set_go(hpet_tick); -} - #define PIT_MODE 0x43 #define PIT_CH0 0x40 @@ -910,7 +557,7 @@ void __init time_init(void) set_normalized_timespec(&wall_to_monotonic, -xtime.tv_sec, -xtime.tv_nsec); - if (!hpet_init()) + if (!hpet_arch_init()) vxtime_hz = (FSEC_PER_SEC + hpet_period / 2) / hpet_period; else hpet_address = 0; @@ -945,42 +592,6 @@ void __init time_init(void) #endif } -static int tsc_unstable = 0; - -void mark_tsc_unstable(void) -{ - tsc_unstable = 1; -} -EXPORT_SYMBOL_GPL(mark_tsc_unstable); - -/* - * Make an educated guess if the TSC is trustworthy and synchronized - * over all CPUs. - */ -__cpuinit int unsynchronized_tsc(void) -{ - if (tsc_unstable) - return 1; - -#ifdef CONFIG_SMP - if (apic_is_clustered_box()) - return 1; -#endif - /* Most intel systems have synchronized TSCs except for - multi node systems */ - if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) { -#ifdef CONFIG_ACPI - /* But TSC doesn't tick in C3 so don't use it there */ - if (acpi_gbl_FADT.header.length > 0 && acpi_gbl_FADT.C3latency < 1000) - return 1; -#endif - return 0; - } - - /* Assume multi socket systems are not synchronized */ - return num_present_cpus() > 1; -} - /* * Decide what mode gettimeofday should use. */ @@ -1116,270 +727,3 @@ static int time_init_device(void) } device_initcall(time_init_device); - -#ifdef CONFIG_HPET_EMULATE_RTC -/* HPET in LegacyReplacement Mode eats up RTC interrupt line. When, HPET - * is enabled, we support RTC interrupt functionality in software. - * RTC has 3 kinds of interrupts: - * 1) Update Interrupt - generate an interrupt, every sec, when RTC clock - * is updated - * 2) Alarm Interrupt - generate an interrupt at a specific time of day - * 3) Periodic Interrupt - generate periodic interrupt, with frequencies - * 2Hz-8192Hz (2Hz-64Hz for non-root user) (all freqs in powers of 2) - * (1) and (2) above are implemented using polling at a frequency of - * 64 Hz. The exact frequency is a tradeoff between accuracy and interrupt - * overhead. (DEFAULT_RTC_INT_FREQ) - * For (3), we use interrupts at 64Hz or user specified periodic - * frequency, whichever is higher. - */ -#include <linux/rtc.h> - -#define DEFAULT_RTC_INT_FREQ 64 -#define RTC_NUM_INTS 1 - -static unsigned long UIE_on; -static unsigned long prev_update_sec; - -static unsigned long AIE_on; -static struct rtc_time alarm_time; - -static unsigned long PIE_on; -static unsigned long PIE_freq = DEFAULT_RTC_INT_FREQ; -static unsigned long PIE_count; - -static unsigned long hpet_rtc_int_freq; /* RTC interrupt frequency */ -static unsigned int hpet_t1_cmp; /* cached comparator register */ - -int is_hpet_enabled(void) -{ - return hpet_address != 0; -} - -/* - * Timer 1 for RTC, we do not use periodic interrupt feature, - * even if HPET supports periodic interrupts on Timer 1. - * The reason being, to set up a periodic interrupt in HPET, we need to - * stop the main counter. And if we do that everytime someone diables/enables - * RTC, we will have adverse effect on main kernel timer running on Timer 0. - * So, for the time being, simulate the periodic interrupt in software. - * - * hpet_rtc_timer_init() is called for the first time and during subsequent - * interuppts reinit happens through hpet_rtc_timer_reinit(). - */ -int hpet_rtc_timer_init(void) -{ - unsigned int cfg, cnt; - unsigned long flags; - - if (!is_hpet_enabled()) - return 0; - /* - * Set the counter 1 and enable the interrupts. - */ - if (PIE_on && (PIE_freq > DEFAULT_RTC_INT_FREQ)) - hpet_rtc_int_freq = PIE_freq; - else - hpet_rtc_int_freq = DEFAULT_RTC_INT_FREQ; - - local_irq_save(flags); - - cnt = hpet_readl(HPET_COUNTER); - cnt += ((hpet_tick*HZ)/hpet_rtc_int_freq); - hpet_writel(cnt, HPET_T1_CMP); - hpet_t1_cmp = cnt; - - cfg = hpet_readl(HPET_T1_CFG); - cfg &= ~HPET_TN_PERIODIC; - cfg |= HPET_TN_ENABLE | HPET_TN_32BIT; - hpet_writel(cfg, HPET_T1_CFG); - - local_irq_restore(flags); - - return 1; -} - -static void hpet_rtc_timer_reinit(void) -{ - unsigned int cfg, cnt, ticks_per_int, lost_ints; - - if (unlikely(!(PIE_on | AIE_on | UIE_on))) { - cfg = hpet_readl(HPET_T1_CFG); - cfg &= ~HPET_TN_ENABLE; - hpet_writel(cfg, HPET_T1_CFG); - return; - } - - if (PIE_on && (PIE_freq > DEFAULT_RTC_INT_FREQ)) - hpet_rtc_int_freq = PIE_freq; - else - hpet_rtc_int_freq = DEFAULT_RTC_INT_FREQ; - - /* It is more accurate to use the comparator value than current count.*/ - ticks_per_int = hpet_tick * HZ / hpet_rtc_int_freq; - hpet_t1_cmp += ticks_per_int; - hpet_writel(hpet_t1_cmp, HPET_T1_CMP); - - /* - * If the interrupt handler was delayed too long, the write above tries - * to schedule the next interrupt in the past and the hardware would - * not interrupt until the counter had wrapped around. - * So we have to check that the comparator wasn't set to a past time. - */ - cnt = hpet_readl(HPET_COUNTER); - if (unlikely((int)(cnt - hpet_t1_cmp) > 0)) { - lost_ints = (cnt - hpet_t1_cmp) / ticks_per_int + 1; - /* Make sure that, even with the time needed to execute - * this code, the next scheduled interrupt has been moved - * back to the future: */ - lost_ints++; - - hpet_t1_cmp += lost_ints * ticks_per_int; - hpet_writel(hpet_t1_cmp, HPET_T1_CMP); - - if (PIE_on) - PIE_count += lost_ints; - - if (printk_ratelimit()) - printk(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n", - hpet_rtc_int_freq); - } -} - -/* - * The functions below are called from rtc driver. - * Return 0 if HPET is not being used. - * Otherwise do the necessary changes and return 1. - */ -int hpet_mask_rtc_irq_bit(unsigned long bit_mask) -{ - if (!is_hpet_enabled()) - return 0; - - if (bit_mask & RTC_UIE) - UIE_on = 0; - if (bit_mask & RTC_PIE) - PIE_on = 0; - if (bit_mask & RTC_AIE) - AIE_on = 0; - - return 1; -} - -int hpet_set_rtc_irq_bit(unsigned long bit_mask) -{ - int timer_init_reqd = 0; - - if (!is_hpet_enabled()) - return 0; - - if (!(PIE_on | AIE_on | UIE_on)) - timer_init_reqd = 1; - - if (bit_mask & RTC_UIE) { - UIE_on = 1; - } - if (bit_mask & RTC_PIE) { - PIE_on = 1; - PIE_count = 0; - } - if (bit_mask & RTC_AIE) { - AIE_on = 1; - } - - if (timer_init_reqd) - hpet_rtc_timer_init(); - - return 1; -} - -int hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec) -{ - if (!is_hpet_enabled()) - return 0; - - alarm_time.tm_hour = hrs; - alarm_time.tm_min = min; - alarm_time.tm_sec = sec; - - return 1; -} - -int hpet_set_periodic_freq(unsigned long freq) -{ - if (!is_hpet_enabled()) - return 0; - - PIE_freq = freq; - PIE_count = 0; - - return 1; -} - -int hpet_rtc_dropped_irq(void) -{ - if (!is_hpet_enabled()) - return 0; - - return 1; -} - -irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs) -{ - struct rtc_time curr_time; - unsigned long rtc_int_flag = 0; - int call_rtc_interrupt = 0; - - hpet_rtc_timer_reinit(); - - if (UIE_on | AIE_on) { - rtc_get_rtc_time(&curr_time); - } - if (UIE_on) { - if (curr_time.tm_sec != prev_update_sec) { - /* Set update int info, call real rtc int routine */ - call_rtc_interrupt = 1; - rtc_int_flag = RTC_UF; - prev_update_sec = curr_time.tm_sec; - } - } - if (PIE_on) { - PIE_count++; - if (PIE_count >= hpet_rtc_int_freq/PIE_freq) { - /* Set periodic int info, call real rtc int routine */ - call_rtc_interrupt = 1; - rtc_int_flag |= RTC_PF; - PIE_count = 0; - } - } - if (AIE_on) { - if ((curr_time.tm_sec == alarm_time.tm_sec) && - (curr_time.tm_min == alarm_time.tm_min) && - (curr_time.tm_hour == alarm_time.tm_hour)) { - /* Set alarm int info, call real rtc int routine */ - call_rtc_interrupt = 1; - rtc_int_flag |= RTC_AF; - } - } - if (call_rtc_interrupt) { - rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8)); - rtc_interrupt(rtc_int_flag, dev_id); - } - return IRQ_HANDLED; -} -#endif - -static int __init nohpet_setup(char *s) -{ - nohpet = 1; - return 1; -} - -__setup("nohpet", nohpet_setup); - -int __init notsc_setup(char *s) -{ - notsc = 1; - return 1; -} - -__setup("notsc", notsc_setup); |
