1 /* 2 * arch/sh/kernel/time.c 3 * 4 * Copyright (C) 1999 Tetsuya Okada & Niibe Yutaka 5 * Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org> 6 * Copyright (C) 2002, 2003, 2004, 2005 Paul Mundt 7 * Copyright (C) 2002 M. R. Brown <mrbrown@linux-sh.org> 8 * 9 * Some code taken from i386 version. 10 * Copyright (C) 1991, 1992, 1995 Linus Torvalds 11 */ 12 13 #include <linux/config.h> 14 #include <linux/kernel.h> 15 #include <linux/module.h> 16 #include <linux/init.h> 17 #include <linux/profile.h> 18 #include <asm/clock.h> 19 #include <asm/rtc.h> 20 #include <asm/timer.h> 21 #include <asm/kgdb.h> 22 23 extern unsigned long wall_jiffies; 24 struct sys_timer *sys_timer; 25 26 /* Move this somewhere more sensible.. */ 27 DEFINE_SPINLOCK(rtc_lock); 28 EXPORT_SYMBOL(rtc_lock); 29 30 /* XXX: Can we initialize this in a routine somewhere? Dreamcast doesn't want 31 * these routines anywhere... */ 32 #ifdef CONFIG_SH_RTC 33 void (*rtc_get_time)(struct timespec *) = sh_rtc_gettimeofday; 34 int (*rtc_set_time)(const time_t) = sh_rtc_settimeofday; 35 #else 36 void (*rtc_get_time)(struct timespec *); 37 int (*rtc_set_time)(const time_t); 38 #endif 39 40 /* 41 * Scheduler clock - returns current time in nanosec units. 42 */ 43 unsigned long long __attribute__ ((weak)) sched_clock(void) 44 { 45 return (unsigned long long)jiffies * (1000000000 / HZ); 46 } 47 48 void do_gettimeofday(struct timeval *tv) 49 { 50 unsigned long seq; 51 unsigned long usec, sec; 52 unsigned long lost; 53 54 do { 55 seq = read_seqbegin(&xtime_lock); 56 usec = get_timer_offset(); 57 58 lost = jiffies - wall_jiffies; 59 if (lost) 60 usec += lost * (1000000 / HZ); 61 62 sec = xtime.tv_sec; 63 usec += xtime.tv_nsec / 1000; 64 } while (read_seqretry(&xtime_lock, seq)); 65 66 while (usec >= 1000000) { 67 usec -= 1000000; 68 sec++; 69 } 70 71 tv->tv_sec = sec; 72 tv->tv_usec = usec; 73 } 74 75 EXPORT_SYMBOL(do_gettimeofday); 76 77 int do_settimeofday(struct timespec *tv) 78 { 79 time_t wtm_sec, sec = tv->tv_sec; 80 long wtm_nsec, nsec = tv->tv_nsec; 81 82 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) 83 return -EINVAL; 84 85 write_seqlock_irq(&xtime_lock); 86 /* 87 * This is revolting. We need to set "xtime" correctly. However, the 88 * value in this location is the value at the most recent update of 89 * wall time. Discover what correction gettimeofday() would have 90 * made, and then undo it! 91 */ 92 nsec -= 1000 * (get_timer_offset() + 93 (jiffies - wall_jiffies) * (1000000 / HZ)); 94 95 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); 96 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); 97 98 set_normalized_timespec(&xtime, sec, nsec); 99 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); 100 101 ntp_clear(); 102 write_sequnlock_irq(&xtime_lock); 103 clock_was_set(); 104 105 return 0; 106 } 107 108 EXPORT_SYMBOL(do_settimeofday); 109 110 /* last time the RTC clock got updated */ 111 static long last_rtc_update; 112 113 /* 114 * handle_timer_tick() needs to keep up the real-time clock, 115 * as well as call the "do_timer()" routine every clocktick 116 */ 117 void handle_timer_tick(struct pt_regs *regs) 118 { 119 do_timer(regs); 120 #ifndef CONFIG_SMP 121 update_process_times(user_mode(regs)); 122 #endif 123 profile_tick(CPU_PROFILING, regs); 124 125 #ifdef CONFIG_HEARTBEAT 126 if (sh_mv.mv_heartbeat != NULL) 127 sh_mv.mv_heartbeat(); 128 #endif 129 130 /* 131 * If we have an externally synchronized Linux clock, then update 132 * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be 133 * called as close as possible to 500 ms before the new second starts. 134 */ 135 if (ntp_synced() && 136 xtime.tv_sec > last_rtc_update + 660 && 137 (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 && 138 (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) { 139 if (rtc_set_time(xtime.tv_sec) == 0) 140 last_rtc_update = xtime.tv_sec; 141 else 142 /* do it again in 60s */ 143 last_rtc_update = xtime.tv_sec - 600; 144 } 145 } 146 147 static struct sysdev_class timer_sysclass = { 148 set_kset_name("timer"), 149 }; 150 151 static int __init timer_init_sysfs(void) 152 { 153 int ret = sysdev_class_register(&timer_sysclass); 154 if (ret != 0) 155 return ret; 156 157 sys_timer->dev.cls = &timer_sysclass; 158 return sysdev_register(&sys_timer->dev); 159 } 160 161 device_initcall(timer_init_sysfs); 162 163 void (*board_time_init)(void); 164 165 void __init time_init(void) 166 { 167 if (board_time_init) 168 board_time_init(); 169 170 clk_init(); 171 172 if (rtc_get_time) { 173 rtc_get_time(&xtime); 174 } else { 175 xtime.tv_sec = mktime(2000, 1, 1, 0, 0, 0); 176 xtime.tv_nsec = 0; 177 } 178 179 set_normalized_timespec(&wall_to_monotonic, 180 -xtime.tv_sec, -xtime.tv_nsec); 181 182 /* 183 * Find the timer to use as the system timer, it will be 184 * initialized for us. 185 */ 186 sys_timer = get_sys_timer(); 187 printk(KERN_INFO "Using %s for system timer\n", sys_timer->name); 188 189 #if defined(CONFIG_SH_KGDB) 190 /* 191 * Set up kgdb as requested. We do it here because the serial 192 * init uses the timer vars we just set up for figuring baud. 193 */ 194 kgdb_init(); 195 #endif 196 } 197