X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=arch%2Fmips%2Fkernel%2Ftime.c;h=fb749740551090577c8a7e044275640763ed5e74;hb=3bfe68580a9d2a25465fc004986acd7991d700d1;hp=fbc153c8f833a8c6f793a871eb3f7110a7a7e4b7;hpb=ec74e361f1e71a2498e48b62abdc4bd8d2423354;p=safe%2Fjmp%2Flinux-2.6 diff --git a/arch/mips/kernel/time.c b/arch/mips/kernel/time.c index fbc153c..fb74974 100644 --- a/arch/mips/kernel/time.c +++ b/arch/mips/kernel/time.c @@ -3,14 +3,15 @@ * 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. + * Common time service routines for MIPS machines. * * 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 +#include #include #include #include @@ -19,737 +20,107 @@ #include #include #include -#include #include -#include #include -#include -#include -#include -#include #include #include -#include +#include #include /* - * 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) - -u64 jiffies_64 = INITIAL_JIFFIES; - -EXPORT_SYMBOL(jiffies_64); - -/* * forward reference */ -extern volatile unsigned long wall_jiffies; - DEFINE_SPINLOCK(rtc_lock); +EXPORT_SYMBOL(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_get_time)(void) = null_rtc_get_time; -int (*rtc_set_time)(unsigned long) = null_rtc_set_time; -int (*rtc_set_mmss)(unsigned long); - - -/* usecs per counter cycle, shifted to left by 32 bits */ -static unsigned int sll32_usecs_per_cycle; - -/* how many counter cycles in a jiffy */ -static unsigned long cycles_per_jiffy __read_mostly; - -/* Cycle counter value at the previous timer interrupt.. */ -static unsigned int timerhi, timerlo; - -/* 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 unsigned int null_hpt_read(void) +int __weak rtc_mips_set_time(unsigned long sec) { return 0; } -static void null_hpt_init(unsigned int count) +int __weak rtc_mips_set_mmss(unsigned long nowtime) { - /* nothing */ + return rtc_mips_set_time(nowtime); } - -/* - * Timer ack for an R4k-compatible timer of a known frequency. - */ -static void c0_timer_ack(void) +int update_persistent_clock(struct timespec now) { - 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. */ - count = read_c0_count(); - if ((count - expirelo) < 0x7fffffff) { - /* missed_timer_count++; */ - expirelo = count + cycles_per_jiffy; - write_c0_compare(expirelo); - } + return rtc_mips_set_mmss(now.tv_sec); } -/* - * High precision timer functions for a R4k-compatible timer. - */ -static unsigned int c0_hpt_read(void) -{ - return read_c0_count(); -} - -/* For use solely as a high precision timer. */ -static void c0_hpt_init(unsigned int count) -{ - write_c0_count(read_c0_count() - count); -} - -/* For use both as a high precision timer and an interrupt source. */ -static void c0_hpt_timer_init(unsigned int count) -{ - count = read_c0_count() - count; - expirelo = (count / cycles_per_jiffy + 1) * cycles_per_jiffy; - write_c0_count(expirelo - cycles_per_jiffy); - write_c0_compare(expirelo); - write_c0_count(count); -} - -int (*mips_timer_state)(void); -void (*mips_timer_ack)(void); -unsigned int (*mips_hpt_read)(void); -void (*mips_hpt_init)(unsigned int); - - -/* - * This version of gettimeofday has microsecond resolution and better than - * microsecond precision on fast machines with cycle counter. - */ -void do_gettimeofday(struct timeval *tv) +static int null_perf_irq(void) { - unsigned long seq; - unsigned long lost; - unsigned long usec, sec; - unsigned long max_ntp_tick = tick_usec - tickadj; - - do { - seq = read_seqbegin(&xtime_lock); - - usec = do_gettimeoffset(); - - lost = jiffies - wall_jiffies; - - /* - * If time_adjust is negative then NTP is slowing the clock - * so make sure not to go into next possible interval. - * Better to lose some accuracy than have time go backwards.. - */ - if (unlikely(time_adjust < 0)) { - usec = min(usec, max_ntp_tick); - - if (lost) - usec += lost * max_ntp_tick; - } else if (unlikely(lost)) - usec += lost * tick_usec; - - sec = xtime.tv_sec; - usec += (xtime.tv_nsec / 1000); - - } while (read_seqretry(&xtime_lock, seq)); - - while (usec >= 1000000) { - usec -= 1000000; - sec++; - } - - tv->tv_sec = sec; - tv->tv_usec = usec; -} - -EXPORT_SYMBOL(do_gettimeofday); - -int do_settimeofday(struct timespec *tv) -{ - time_t wtm_sec, sec = tv->tv_sec; - long wtm_nsec, nsec = tv->tv_nsec; - - if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) - return -EINVAL; - - write_seqlock_irq(&xtime_lock); - - /* - * This is revolting. We need to set "xtime" correctly. However, - * the value in this location is the value at the most recent update - * of wall time. Discover what correction gettimeofday() would have - * made, and then undo it! - */ - nsec -= do_gettimeoffset() * NSEC_PER_USEC; - nsec -= (jiffies - wall_jiffies) * tick_nsec; - - wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); - wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); - - set_normalized_timespec(&xtime, sec, nsec); - set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); - - ntp_clear(); - write_sequnlock_irq(&xtime_lock); - clock_was_set(); return 0; } -EXPORT_SYMBOL(do_settimeofday); - -/* - * Gettimeoffset routines. These routines returns the time duration - * since last timer interrupt in usecs. - * - * If the exact CPU counter frequency is known, use fixed_rate_gettimeoffset. - * Otherwise use calibrate_gettimeoffset() - * - * If the CPU does not have the counter register, you can either supply - * your own gettimeoffset() routine, or use null_gettimeoffset(), which - * gives the same resolution as HZ. - */ - -static unsigned long null_gettimeoffset(void) -{ - return 0; -} - - -/* The function pointer to one of the gettimeoffset funcs. */ -unsigned long (*do_gettimeoffset)(void) = null_gettimeoffset; - - -static unsigned long fixed_rate_gettimeoffset(void) -{ - u32 count; - unsigned long res; - - /* Get last timer tick in absolute kernel time */ - count = mips_hpt_read(); - - /* .. relative to previous jiffy (32 bits is enough) */ - count -= timerlo; - - __asm__("multu %1,%2" - : "=h" (res) - : "r" (count), "r" (sll32_usecs_per_cycle) - : "lo", GCC_REG_ACCUM); - - /* - * Due to possible jiffies inconsistencies, we need to check - * the result so that we'll get a timer that is monotonic. - */ - if (res >= USECS_PER_JIFFY) - res = USECS_PER_JIFFY - 1; - - return res; -} - - -/* - * Cached "1/(clocks per usec) * 2^32" value. - * It has to be recalculated once each jiffy. - */ -static unsigned long cached_quotient; - -/* Last jiffy when calibrate_divXX_gettimeoffset() was called. */ -static unsigned long last_jiffies; - -/* - * This is moved from dec/time.c:do_ioasic_gettimeoffset() by Maciej. - */ -static unsigned long calibrate_div32_gettimeoffset(void) -{ - u32 count; - unsigned long res, tmp; - unsigned long quotient; - - tmp = jiffies; - - quotient = cached_quotient; - - if (last_jiffies != tmp) { - last_jiffies = tmp; - if (last_jiffies != 0) { - unsigned long r0; - do_div64_32(r0, timerhi, timerlo, tmp); - do_div64_32(quotient, USECS_PER_JIFFY, - USECS_PER_JIFFY_FRAC, r0); - cached_quotient = quotient; - } - } - - /* Get last timer tick in absolute kernel time */ - count = mips_hpt_read(); - - /* .. relative to previous jiffy (32 bits is enough) */ - count -= timerlo; - - __asm__("multu %1,%2" - : "=h" (res) - : "r" (count), "r" (quotient) - : "lo", GCC_REG_ACCUM); - - /* - * Due to possible jiffies inconsistencies, we need to check - * the result so that we'll get a timer that is monotonic. - */ - if (res >= USECS_PER_JIFFY) - res = USECS_PER_JIFFY - 1; - - return res; -} - -static unsigned long calibrate_div64_gettimeoffset(void) -{ - u32 count; - unsigned long res, tmp; - unsigned long quotient; - - tmp = jiffies; - - quotient = cached_quotient; - - if (last_jiffies != tmp) { - last_jiffies = tmp; - if (last_jiffies) { - unsigned long r0; - __asm__(".set push\n\t" - ".set mips3\n\t" - "lwu %0,%3\n\t" - "dsll32 %1,%2,0\n\t" - "or %1,%1,%0\n\t" - "ddivu $0,%1,%4\n\t" - "mflo %1\n\t" - "dsll32 %0,%5,0\n\t" - "or %0,%0,%6\n\t" - "ddivu $0,%0,%1\n\t" - "mflo %0\n\t" - ".set pop" - : "=&r" (quotient), "=&r" (r0) - : "r" (timerhi), "m" (timerlo), - "r" (tmp), "r" (USECS_PER_JIFFY), - "r" (USECS_PER_JIFFY_FRAC) - : "hi", "lo", GCC_REG_ACCUM); - cached_quotient = quotient; - } - } - - /* Get last timer tick in absolute kernel time */ - count = mips_hpt_read(); - - /* .. relative to previous jiffy (32 bits is enough) */ - count -= timerlo; - - __asm__("multu %1,%2" - : "=h" (res) - : "r" (count), "r" (quotient) - : "lo", GCC_REG_ACCUM); - - /* - * Due to possible jiffies inconsistencies, we need to check - * the result so that we'll get a timer that is monotonic. - */ - if (res >= USECS_PER_JIFFY) - res = USECS_PER_JIFFY - 1; - - return res; -} - +int (*perf_irq)(void) = null_perf_irq; -/* 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, struct pt_regs *regs) -{ - if (current->pid) - profile_tick(CPU_PROFILING, regs); - update_process_times(user_mode(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, struct pt_regs *regs) -{ - unsigned long j; - unsigned int count; - - count = mips_hpt_read(); - mips_timer_ack(); - - /* Update timerhi/timerlo for intra-jiffy calibration. */ - timerhi += count < timerlo; /* Wrap around */ - timerlo = count; - - /* - * call the generic timer interrupt handling - */ - do_timer(regs); - - /* - * If we have an externally synchronized Linux clock, then update - * CMOS clock accordingly every ~11 minutes. rtc_set_time() has to be - * called as close as possible to 500 ms before the new second starts. - */ - write_seqlock(&xtime_lock); - 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_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); - - /* - * If jiffies has overflown in this timer_interrupt, we must - * update the timer[hi]/[lo] to make fast gettimeoffset funcs - * quotient calc still valid. -arca - * - * The first timer interrupt comes late as interrupts are - * enabled long after timers are initialized. Therefore the - * high precision timer is fast, leading to wrong gettimeoffset() - * calculations. We deal with it by setting it based on the - * number of its ticks between the second and the third interrupt. - * That is still somewhat imprecise, but it's a good estimate. - * --macro - */ - j = jiffies; - if (j < 4) { - static unsigned int prev_count; - static int hpt_initialized; - - switch (j) { - case 0: - timerhi = timerlo = 0; - mips_hpt_init(count); - break; - case 2: - prev_count = count; - break; - case 3: - if (!hpt_initialized) { - unsigned int c3 = 3 * (count - prev_count); - - timerhi = 0; - timerlo = c3; - mips_hpt_init(count - c3); - hpt_initialized = 1; - } - break; - default: - break; - } - } - - /* - * 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, regs); - - return IRQ_HANDLED; -} - -asmlinkage void ll_timer_interrupt(int irq, struct pt_regs *regs) -{ - irq_enter(); - kstat_this_cpu.irqs[irq]++; - - /* we keep interrupt disabled all the time */ - timer_interrupt(irq, NULL, regs); - - irq_exit(); -} - -asmlinkage void ll_local_timer_interrupt(int irq, struct pt_regs *regs) -{ - irq_enter(); - if (smp_processor_id() != 0) - kstat_this_cpu.irqs[irq]++; - - /* we keep interrupt disabled all the time */ - local_timer_interrupt(irq, NULL, regs); - - irq_exit(); -} +EXPORT_SYMBOL(perf_irq); /* * time_init() - it does the following things. * - * 1) board_time_init() - + * 1) plat_time_init() - * a) (optional) set up RTC routines, * b) (optional) calibrate and set the mips_hpt_frequency - * (only needed if you intended to use fixed_rate_gettimeoffset - * or use cpu counter as timer interrupt source) - * 2) setup xtime based on rtc_get_time(). - * 3) choose a appropriate gettimeoffset routine. - * 4) calculate a couple of cached variables for later usage - * 5) board_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 + * (only needed if you intended to use cpu counter as timer interrupt + * source) + * 2) calculate a couple of cached variables for later usage */ -void (*board_time_init)(void); -void (*board_timer_setup)(struct irqaction *irq); - unsigned int mips_hpt_frequency; -static struct irqaction timer_irqaction = { - .handler = timer_interrupt, - .flags = SA_INTERRUPT, - .name = "timer", -}; - -static unsigned int __init calibrate_hpt(void) +/* + * This function exists in order to cause an error due to a duplicate + * definition if platform code should have its own implementation. The hook + * to use instead is plat_time_init. plat_time_init does not receive the + * irqaction pointer argument anymore. This is because any function which + * initializes an interrupt timer now takes care of its own request_irq rsp. + * setup_irq calls and each clock_event_device should use its own + * struct irqrequest. + */ +void __init plat_timer_setup(void) { - u64 frequency; - u32 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 = mips_hpt_read(); - do { - while (mips_timer_state()); - while (!mips_timer_state()); - } while (--i); - hpt_end = mips_hpt_read(); - - hpt_count = hpt_end - hpt_start; - hz = HZ; - frequency = (u64)hpt_count * (u64)hz; - - return frequency >> log_2_loops; + BUG(); } -void __init time_init(void) +static __init int cpu_has_mfc0_count_bug(void) { - if (board_time_init) - board_time_init(); - - if (!rtc_set_mmss) - rtc_set_mmss = rtc_set_time; - - xtime.tv_sec = rtc_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 && !mips_hpt_read) { - /* No high precision timer -- sorry. */ - mips_hpt_read = null_hpt_read; - mips_hpt_init = null_hpt_init; - } else if (!mips_hpt_frequency && !mips_timer_state) { - /* A high precision timer of unknown frequency. */ - if (!mips_hpt_read) { - /* No external high precision timer -- use R4k. */ - mips_hpt_read = c0_hpt_read; - mips_hpt_init = c0_hpt_init; - } - - if ((current_cpu_data.isa_level == MIPS_CPU_ISA_M32) || - (current_cpu_data.isa_level == MIPS_CPU_ISA_I) || - (current_cpu_data.isa_level == MIPS_CPU_ISA_II)) - /* - * We need to calibrate the counter but we don't have - * 64-bit division. - */ - do_gettimeoffset = calibrate_div32_gettimeoffset; - else - /* - * We need to calibrate the counter but we *do* have - * 64-bit division. - */ - do_gettimeoffset = calibrate_div64_gettimeoffset; - } else { - /* We know counter frequency. Or we can get it. */ - if (!mips_hpt_read) { - /* No external high precision timer -- use R4k. */ - mips_hpt_read = c0_hpt_read; - - if (mips_timer_state) - mips_hpt_init = c0_hpt_init; - else { - /* No external timer interrupt -- use R4k. */ - mips_hpt_init = c0_hpt_timer_init; - mips_timer_ack = c0_timer_ack; - } - } - if (!mips_hpt_frequency) - mips_hpt_frequency = calibrate_hpt(); - - do_gettimeoffset = fixed_rate_gettimeoffset; - - /* Calculate cache parameters. */ - cycles_per_jiffy = (mips_hpt_frequency + HZ / 2) / HZ; + switch (current_cpu_type()) { + case CPU_R4000PC: + case CPU_R4000SC: + case CPU_R4000MC: + /* + * V3.0 is documented as suffering from the mfc0 from count bug. + * Afaik this is the last version of the R4000. Later versions + * were marketed as R4400. + */ + return 1; - /* sll32_usecs_per_cycle = 10^6 * 2^32 / mips_counter_freq */ - do_div64_32(sll32_usecs_per_cycle, - 1000000, mips_hpt_frequency / 2, - mips_hpt_frequency); + case CPU_R4400PC: + case CPU_R4400SC: + case CPU_R4400MC: + /* + * The published errata for the R4400 upto 3.0 say the CPU + * has the mfc0 from count bug. + */ + if ((current_cpu_data.processor_id & 0xff) <= 0x30) + return 1; - /* 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); + /* + * we assume newer revisions are ok + */ + return 0; } - if (!mips_timer_ack) - /* No timer interrupt ack (e.g. i8254). */ - mips_timer_ack = null_timer_ack; - - /* This sets up the high precision timer for the first interrupt. */ - mips_hpt_init(mips_hpt_read()); - - /* - * 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. - */ - board_timer_setup(&timer_irqaction); + return 0; } -#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) +void __init time_init(void) { - 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 */ + plat_time_init(); - /* 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_set_time); -EXPORT_SYMBOL(rtc_get_time); - -unsigned long long sched_clock(void) -{ - return (unsigned long long)jiffies*(1000000000/HZ); + if (!mips_clockevent_init() || !cpu_has_mfc0_count_bug()) + init_mips_clocksource(); }