Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/arch/arm26/kernel/time.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992, 1995 Linus Torvalds |
| 5 | * Modifications for ARM (C) 1994-2001 Russell King |
| 6 | * Mods for ARM26 (C) 2003 Ian Molton |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License version 2 as |
| 10 | * published by the Free Software Foundation. |
| 11 | * |
| 12 | * This file contains the ARM-specific time handling details: |
| 13 | * reading the RTC at bootup, etc... |
| 14 | * |
| 15 | * 1994-07-02 Alan Modra |
| 16 | * fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime |
| 17 | * 1998-12-20 Updated NTP code according to technical memorandum Jan '96 |
| 18 | * "A Kernel Model for Precision Timekeeping" by Dave Mills |
| 19 | */ |
| 20 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | #include <linux/module.h> |
| 22 | #include <linux/kernel.h> |
| 23 | #include <linux/interrupt.h> |
| 24 | #include <linux/time.h> |
| 25 | #include <linux/init.h> |
| 26 | #include <linux/smp.h> |
| 27 | #include <linux/timex.h> |
| 28 | #include <linux/errno.h> |
| 29 | #include <linux/profile.h> |
| 30 | |
| 31 | #include <asm/hardware.h> |
| 32 | #include <asm/io.h> |
| 33 | #include <asm/irq.h> |
| 34 | #include <asm/ioc.h> |
| 35 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | /* this needs a better home */ |
| 37 | DEFINE_SPINLOCK(rtc_lock); |
| 38 | |
| 39 | /* change this if you have some constant time drift */ |
| 40 | #define USECS_PER_JIFFY (1000000/HZ) |
| 41 | |
| 42 | static int dummy_set_rtc(void) |
| 43 | { |
| 44 | return 0; |
| 45 | } |
| 46 | |
| 47 | /* |
| 48 | * hook for setting the RTC's idea of the current time. |
| 49 | */ |
| 50 | int (*set_rtc)(void) = dummy_set_rtc; |
| 51 | |
| 52 | /* |
| 53 | * Get time offset based on IOCs timer. |
| 54 | * FIXME - if this is called with interrutps off, why the shennanigans |
| 55 | * below ? |
| 56 | */ |
| 57 | static unsigned long gettimeoffset(void) |
| 58 | { |
| 59 | unsigned int count1, count2, status; |
| 60 | long offset; |
| 61 | |
| 62 | ioc_writeb (0, IOC_T0LATCH); |
| 63 | barrier (); |
| 64 | count1 = ioc_readb(IOC_T0CNTL) | (ioc_readb(IOC_T0CNTH) << 8); |
| 65 | barrier (); |
| 66 | status = ioc_readb(IOC_IRQREQA); |
| 67 | barrier (); |
| 68 | ioc_writeb (0, IOC_T0LATCH); |
| 69 | barrier (); |
| 70 | count2 = ioc_readb(IOC_T0CNTL) | (ioc_readb(IOC_T0CNTH) << 8); |
| 71 | |
| 72 | offset = count2; |
| 73 | if (count2 < count1) { |
| 74 | /* |
| 75 | * We have not had an interrupt between reading count1 |
| 76 | * and count2. |
| 77 | */ |
| 78 | if (status & (1 << 5)) |
| 79 | offset -= LATCH; |
| 80 | } else if (count2 > count1) { |
| 81 | /* |
| 82 | * We have just had another interrupt between reading |
| 83 | * count1 and count2. |
| 84 | */ |
| 85 | offset -= LATCH; |
| 86 | } |
| 87 | |
| 88 | offset = (LATCH - offset) * (tick_nsec / 1000); |
| 89 | return (offset + LATCH/2) / LATCH; |
| 90 | } |
| 91 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 92 | static unsigned long next_rtc_update; |
| 93 | |
| 94 | /* |
| 95 | * If we have an externally synchronized linux clock, then update |
| 96 | * CMOS clock accordingly every ~11 minutes. set_rtc() has to be |
| 97 | * called as close as possible to 500 ms before the new second |
| 98 | * starts. |
| 99 | */ |
| 100 | static inline void do_set_rtc(void) |
| 101 | { |
john stultz | b149ee2 | 2005-09-06 15:17:46 -0700 | [diff] [blame] | 102 | if (!ntp_synced() || set_rtc == NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | return; |
| 104 | |
| 105 | //FIXME - timespec.tv_sec is a time_t not unsigned long |
| 106 | if (next_rtc_update && |
| 107 | time_before((unsigned long)xtime.tv_sec, next_rtc_update)) |
| 108 | return; |
| 109 | |
| 110 | if (xtime.tv_nsec < 500000000 - ((unsigned) tick_nsec >> 1) && |
| 111 | xtime.tv_nsec >= 500000000 + ((unsigned) tick_nsec >> 1)) |
| 112 | return; |
| 113 | |
| 114 | if (set_rtc()) |
| 115 | /* |
| 116 | * rtc update failed. Try again in 60s |
| 117 | */ |
| 118 | next_rtc_update = xtime.tv_sec + 60; |
| 119 | else |
| 120 | next_rtc_update = xtime.tv_sec + 660; |
| 121 | } |
| 122 | |
| 123 | #define do_leds() |
| 124 | |
| 125 | void do_gettimeofday(struct timeval *tv) |
| 126 | { |
| 127 | unsigned long flags; |
| 128 | unsigned long seq; |
Atsushi Nemoto | 8ef3860 | 2006-09-30 23:28:31 -0700 | [diff] [blame] | 129 | unsigned long usec, sec; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | |
| 131 | do { |
| 132 | seq = read_seqbegin_irqsave(&xtime_lock, flags); |
| 133 | usec = gettimeoffset(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 134 | sec = xtime.tv_sec; |
| 135 | usec += xtime.tv_nsec / 1000; |
| 136 | } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); |
| 137 | |
| 138 | /* usec may have gone up a lot: be safe */ |
| 139 | while (usec >= 1000000) { |
| 140 | usec -= 1000000; |
| 141 | sec++; |
| 142 | } |
| 143 | |
| 144 | tv->tv_sec = sec; |
| 145 | tv->tv_usec = usec; |
| 146 | } |
| 147 | |
| 148 | EXPORT_SYMBOL(do_gettimeofday); |
| 149 | |
| 150 | int do_settimeofday(struct timespec *tv) |
| 151 | { |
| 152 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) |
| 153 | return -EINVAL; |
| 154 | |
| 155 | write_seqlock_irq(&xtime_lock); |
| 156 | /* |
| 157 | * This is revolting. We need to set "xtime" correctly. However, the |
| 158 | * value in this location is the value at the most recent update of |
| 159 | * wall time. Discover what correction gettimeofday() would have |
| 160 | * done, and then undo it! |
| 161 | */ |
Atsushi Nemoto | 8ef3860 | 2006-09-30 23:28:31 -0700 | [diff] [blame] | 162 | tv->tv_nsec -= 1000 * gettimeoffset(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 163 | |
| 164 | while (tv->tv_nsec < 0) { |
| 165 | tv->tv_nsec += NSEC_PER_SEC; |
| 166 | tv->tv_sec--; |
| 167 | } |
| 168 | |
| 169 | xtime.tv_sec = tv->tv_sec; |
| 170 | xtime.tv_nsec = tv->tv_nsec; |
john stultz | b149ee2 | 2005-09-06 15:17:46 -0700 | [diff] [blame] | 171 | ntp_clear(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 172 | write_sequnlock_irq(&xtime_lock); |
| 173 | clock_was_set(); |
| 174 | return 0; |
| 175 | } |
| 176 | |
| 177 | EXPORT_SYMBOL(do_settimeofday); |
| 178 | |
| 179 | static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) |
| 180 | { |
Atsushi Nemoto | 3171a03 | 2006-09-29 02:00:32 -0700 | [diff] [blame] | 181 | do_timer(1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 182 | #ifndef CONFIG_SMP |
| 183 | update_process_times(user_mode(regs)); |
| 184 | #endif |
| 185 | do_set_rtc(); //FIME - EVERY timer IRQ? |
| 186 | profile_tick(CPU_PROFILING, regs); |
| 187 | return IRQ_HANDLED; //FIXME - is this right? |
| 188 | } |
| 189 | |
| 190 | static struct irqaction timer_irq = { |
| 191 | .name = "timer", |
Thomas Gleixner | af0f4d3 | 2006-07-01 19:29:12 -0700 | [diff] [blame] | 192 | .flags = IRQF_DISABLED, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 193 | .handler = timer_interrupt, |
| 194 | }; |
| 195 | |
| 196 | extern void ioctime_init(void); |
| 197 | |
| 198 | /* |
| 199 | * Set up timer interrupt. |
| 200 | */ |
| 201 | void __init time_init(void) |
| 202 | { |
| 203 | ioc_writeb(LATCH & 255, IOC_T0LTCHL); |
| 204 | ioc_writeb(LATCH >> 8, IOC_T0LTCHH); |
| 205 | ioc_writeb(0, IOC_T0GO); |
| 206 | |
| 207 | |
| 208 | setup_irq(IRQ_TIMER, &timer_irq); |
| 209 | } |
| 210 | |