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