| /* |
| * 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); |
| |
| /* |
| * Timer interrupt |
| */ |
| int cp0_compare_irq; |
| |
| /* |
| * Performance counter IRQ or -1 if shared with timer |
| */ |
| int cp0_perfcount_irq; |
| EXPORT_SYMBOL_GPL(cp0_perfcount_irq); |
| |
| /* |
| * Possibly handle a performance counter interrupt. |
| * Return true if the timer interrupt should not be checked |
| */ |
| static inline int handle_perf_irq (int r2) |
| { |
| /* |
| * The performance counter overflow interrupt may be shared with the |
| * timer interrupt (cp0_perfcount_irq < 0). If it is and a |
| * performance counter has overflowed (perf_irq() == IRQ_HANDLED) |
| * and we can't reliably determine if a counter interrupt has also |
| * happened (!r2) then don't check for a timer interrupt. |
| */ |
| return (cp0_perfcount_irq < 0) && |
| perf_irq() == IRQ_HANDLED && |
| !r2; |
| } |
| |
| asmlinkage void ll_timer_interrupt(int irq) |
| { |
| int r2 = cpu_has_mips_r2; |
| |
| irq_enter(); |
| kstat_this_cpu.irqs[irq]++; |
| |
| if (handle_perf_irq(r2)) |
| goto out; |
| |
| if (r2 && ((read_c0_cause() & (1 << 30)) == 0)) |
| goto out; |
| |
| 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 | IRQF_PERCPU, |
| .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 = CLOCKSOURCE_MASK(32), |
| .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); |