/* * Copyright 2001 MontaVista Software Inc. * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net * Copyright (c) 2003, 2004 Maciej W. Rozycki * * Common time service routines for MIPS machines. See * Documentation/mips/time.README. * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2 of the License, or (at your * option) any later version. */ #include <linux/types.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/sched.h> #include <linux/param.h> #include <linux/time.h> #include <linux/timex.h> #include <linux/smp.h> #include <linux/kernel_stat.h> #include <linux/spinlock.h> #include <linux/interrupt.h> #include <linux/module.h> #include <asm/bootinfo.h> #include <asm/cache.h> #include <asm/compiler.h> #include <asm/cpu.h> #include <asm/cpu-features.h> #include <asm/div64.h> #include <asm/sections.h> #include <asm/time.h> /* * The integer part of the number of usecs per jiffy is taken from tick, * but the fractional part is not recorded, so we calculate it using the * initial value of HZ. This aids systems where tick isn't really an * integer (e.g. for HZ = 128). */ #define USECS_PER_JIFFY TICK_SIZE #define USECS_PER_JIFFY_FRAC ((unsigned long)(u32)((1000000ULL << 32) / HZ)) #define TICK_SIZE (tick_nsec / 1000) /* * forward reference */ DEFINE_SPINLOCK(rtc_lock); /* * By default we provide the null RTC ops */ static unsigned long null_rtc_get_time(void) { return mktime(2000, 1, 1, 0, 0, 0); } static int null_rtc_set_time(unsigned long sec) { return 0; } unsigned long (*rtc_mips_get_time)(void) = null_rtc_get_time; int (*rtc_mips_set_time)(unsigned long) = null_rtc_set_time; int (*rtc_mips_set_mmss)(unsigned long); /* how many counter cycles in a jiffy */ static unsigned long cycles_per_jiffy __read_mostly; /* expirelo is the count value for next CPU timer interrupt */ static unsigned int expirelo; /* * Null timer ack for systems not needing one (e.g. i8254). */ static void null_timer_ack(void) { /* nothing */ } /* * Null high precision timer functions for systems lacking one. */ static cycle_t null_hpt_read(void) { return 0; } /* * Timer ack for an R4k-compatible timer of a known frequency. */ static void c0_timer_ack(void) { unsigned int count; /* Ack this timer interrupt and set the next one. */ expirelo += cycles_per_jiffy; write_c0_compare(expirelo); /* Check to see if we have missed any timer interrupts. */ while (((count = read_c0_count()) - expirelo) < 0x7fffffff) { /* missed_timer_count++; */ expirelo = count + cycles_per_jiffy; write_c0_compare(expirelo); } } /* * High precision timer functions for a R4k-compatible timer. */ static cycle_t c0_hpt_read(void) { return read_c0_count(); } /* For use both as a high precision timer and an interrupt source. */ static void __init c0_hpt_timer_init(void) { expirelo = read_c0_count() + cycles_per_jiffy; write_c0_compare(expirelo); } int (*mips_timer_state)(void); void (*mips_timer_ack)(void); /* last time when xtime and rtc are sync'ed up */ static long last_rtc_update; /* * local_timer_interrupt() does profiling and process accounting * on a per-CPU basis. * * In UP mode, it is invoked from the (global) timer_interrupt. * * In SMP mode, it might invoked by per-CPU timer interrupt, or * a broadcasted inter-processor interrupt which itself is triggered * by the global timer interrupt. */ void local_timer_interrupt(int irq, void *dev_id) { profile_tick(CPU_PROFILING); update_process_times(user_mode(get_irq_regs())); } /* * High-level timer interrupt service routines. This function * is set as irqaction->handler and is invoked through do_IRQ. */ irqreturn_t timer_interrupt(int irq, void *dev_id) { write_seqlock(&xtime_lock); mips_timer_ack(); /* * call the generic timer interrupt handling */ do_timer(1); /* * If we have an externally synchronized Linux clock, then update * CMOS clock accordingly every ~11 minutes. rtc_mips_set_time() has to be * called as close as possible to 500 ms before the new second starts. */ if (ntp_synced() && xtime.tv_sec > last_rtc_update + 660 && (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 && (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) { if (rtc_mips_set_mmss(xtime.tv_sec) == 0) { last_rtc_update = xtime.tv_sec; } else { /* do it again in 60 s */ last_rtc_update = xtime.tv_sec - 600; } } write_sequnlock(&xtime_lock); /* * In UP mode, we call local_timer_interrupt() to do profiling * and process accouting. * * In SMP mode, local_timer_interrupt() is invoked by appropriate * low-level local timer interrupt handler. */ local_timer_interrupt(irq, dev_id); return IRQ_HANDLED; } int null_perf_irq(void) { return 0; } int (*perf_irq)(void) = null_perf_irq; EXPORT_SYMBOL(null_perf_irq); EXPORT_SYMBOL(perf_irq); asmlinkage void ll_timer_interrupt(int irq) { int r2 = cpu_has_mips_r2; irq_enter(); kstat_this_cpu.irqs[irq]++; /* * Suckage alert: * Before R2 of the architecture there was no way to see if a * performance counter interrupt was pending, so we have to run the * performance counter interrupt handler anyway. */ if (!r2 || (read_c0_cause() & (1 << 26))) if (perf_irq()) goto out; /* we keep interrupt disabled all the time */ if (!r2 || (read_c0_cause() & (1 << 30))) timer_interrupt(irq, NULL); out: irq_exit(); } asmlinkage void ll_local_timer_interrupt(int irq) { irq_enter(); if (smp_processor_id() != 0) kstat_this_cpu.irqs[irq]++; /* we keep interrupt disabled all the time */ local_timer_interrupt(irq, NULL); irq_exit(); } /* * time_init() - it does the following things. * * 1) board_time_init() - * a) (optional) set up RTC routines, * b) (optional) calibrate and set the mips_hpt_frequency * (only needed if you intended to use cpu counter as timer interrupt * source) * 2) setup xtime based on rtc_mips_get_time(). * 3) calculate a couple of cached variables for later usage * 4) plat_timer_setup() - * a) (optional) over-write any choices made above by time_init(). * b) machine specific code should setup the timer irqaction. * c) enable the timer interrupt */ void (*board_time_init)(void); unsigned int mips_hpt_frequency; static struct irqaction timer_irqaction = { .handler = timer_interrupt, .flags = IRQF_DISABLED, .name = "timer", }; static unsigned int __init calibrate_hpt(void) { cycle_t frequency, hpt_start, hpt_end, hpt_count, hz; const int loops = HZ / 10; int log_2_loops = 0; int i; /* * We want to calibrate for 0.1s, but to avoid a 64-bit * division we round the number of loops up to the nearest * power of 2. */ while (loops > 1 << log_2_loops) log_2_loops++; i = 1 << log_2_loops; /* * Wait for a rising edge of the timer interrupt. */ while (mips_timer_state()); while (!mips_timer_state()); /* * Now see how many high precision timer ticks happen * during the calculated number of periods between timer * interrupts. */ hpt_start = clocksource_mips.read(); do { while (mips_timer_state()); while (!mips_timer_state()); } while (--i); hpt_end = clocksource_mips.read(); hpt_count = (hpt_end - hpt_start) & clocksource_mips.mask; hz = HZ; frequency = hpt_count * hz; return frequency >> log_2_loops; } struct clocksource clocksource_mips = { .name = "MIPS", .mask = 0xffffffff, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; static void __init init_mips_clocksource(void) { u64 temp; u32 shift; if (!mips_hpt_frequency || clocksource_mips.read == null_hpt_read) return; /* Calclate a somewhat reasonable rating value */ clocksource_mips.rating = 200 + mips_hpt_frequency / 10000000; /* Find a shift value */ for (shift = 32; shift > 0; shift--) { temp = (u64) NSEC_PER_SEC << shift; do_div(temp, mips_hpt_frequency); if ((temp >> 32) == 0) break; } clocksource_mips.shift = shift; clocksource_mips.mult = (u32)temp; clocksource_register(&clocksource_mips); } void __init time_init(void) { if (board_time_init) board_time_init(); if (!rtc_mips_set_mmss) rtc_mips_set_mmss = rtc_mips_set_time; xtime.tv_sec = rtc_mips_get_time(); xtime.tv_nsec = 0; set_normalized_timespec(&wall_to_monotonic, -xtime.tv_sec, -xtime.tv_nsec); /* Choose appropriate high precision timer routines. */ if (!cpu_has_counter && !clocksource_mips.read) /* No high precision timer -- sorry. */ clocksource_mips.read = null_hpt_read; else if (!mips_hpt_frequency && !mips_timer_state) { /* A high precision timer of unknown frequency. */ if (!clocksource_mips.read) /* No external high precision timer -- use R4k. */ clocksource_mips.read = c0_hpt_read; } else { /* We know counter frequency. Or we can get it. */ if (!clocksource_mips.read) { /* No external high precision timer -- use R4k. */ clocksource_mips.read = c0_hpt_read; if (!mips_timer_state) { /* No external timer interrupt -- use R4k. */ mips_timer_ack = c0_timer_ack; /* Calculate cache parameters. */ cycles_per_jiffy = (mips_hpt_frequency + HZ / 2) / HZ; /* * This sets up the high precision * timer for the first interrupt. */ c0_hpt_timer_init(); } } if (!mips_hpt_frequency) mips_hpt_frequency = calibrate_hpt(); /* Report the high precision timer rate for a reference. */ printk("Using %u.%03u MHz high precision timer.\n", ((mips_hpt_frequency + 500) / 1000) / 1000, ((mips_hpt_frequency + 500) / 1000) % 1000); } if (!mips_timer_ack) /* No timer interrupt ack (e.g. i8254). */ mips_timer_ack = null_timer_ack; /* * Call board specific timer interrupt setup. * * this pointer must be setup in machine setup routine. * * Even if a machine chooses to use a low-level timer interrupt, * it still needs to setup the timer_irqaction. * In that case, it might be better to set timer_irqaction.handler * to be NULL function so that we are sure the high-level code * is not invoked accidentally. */ plat_timer_setup(&timer_irqaction); init_mips_clocksource(); } #define FEBRUARY 2 #define STARTOFTIME 1970 #define SECDAY 86400L #define SECYR (SECDAY * 365) #define leapyear(y) ((!((y) % 4) && ((y) % 100)) || !((y) % 400)) #define days_in_year(y) (leapyear(y) ? 366 : 365) #define days_in_month(m) (month_days[(m) - 1]) static int month_days[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; void to_tm(unsigned long tim, struct rtc_time *tm) { long hms, day, gday; int i; gday = day = tim / SECDAY; hms = tim % SECDAY; /* Hours, minutes, seconds are easy */ tm->tm_hour = hms / 3600; tm->tm_min = (hms % 3600) / 60; tm->tm_sec = (hms % 3600) % 60; /* Number of years in days */ for (i = STARTOFTIME; day >= days_in_year(i); i++) day -= days_in_year(i); tm->tm_year = i; /* Number of months in days left */ if (leapyear(tm->tm_year)) days_in_month(FEBRUARY) = 29; for (i = 1; day >= days_in_month(i); i++) day -= days_in_month(i); days_in_month(FEBRUARY) = 28; tm->tm_mon = i - 1; /* tm_mon starts from 0 to 11 */ /* Days are what is left over (+1) from all that. */ tm->tm_mday = day + 1; /* * Determine the day of week */ tm->tm_wday = (gday + 4) % 7; /* 1970/1/1 was Thursday */ } EXPORT_SYMBOL(rtc_lock); EXPORT_SYMBOL(to_tm); EXPORT_SYMBOL(rtc_mips_set_time); EXPORT_SYMBOL(rtc_mips_get_time);