1/* 2 * linux/arch/m32r/kernel/time.c 3 * 4 * Copyright (c) 2001, 2002 Hiroyuki Kondo, Hirokazu Takata, 5 * Hitoshi Yamamoto 6 * Taken from i386 version. 7 * Copyright (C) 1991, 1992, 1995 Linus Torvalds 8 * Copyright (C) 1996, 1997, 1998 Ralf Baechle 9 * 10 * This file contains the time handling details for PC-style clocks as 11 * found in some MIPS systems. 12 * 13 * Some code taken from sh version. 14 * Copyright (C) 1999 Tetsuya Okada & Niibe Yutaka 15 * Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org> 16 */ 17 18#undef DEBUG_TIMER 19 20#include <linux/errno.h> 21#include <linux/init.h> 22#include <linux/module.h> 23#include <linux/sched.h> 24#include <linux/kernel.h> 25#include <linux/param.h> 26#include <linux/string.h> 27#include <linux/mm.h> 28#include <linux/interrupt.h> 29#include <linux/profile.h> 30 31#include <asm/io.h> 32#include <asm/m32r.h> 33 34#include <asm/hw_irq.h> 35 36#ifdef CONFIG_SMP 37extern void send_IPI_allbutself(int, int); 38extern void smp_local_timer_interrupt(void); 39#endif 40 41#define TICK_SIZE (tick_nsec / 1000) 42 43/* 44 * Change this if you have some constant time drift 45 */ 46 47/* This is for machines which generate the exact clock. */ 48#define USECS_PER_JIFFY (1000000/HZ) 49 50static unsigned long latch; 51 52static unsigned long do_gettimeoffset(void) 53{ 54 unsigned long elapsed_time = 0; /* [us] */ 55 56#if defined(CONFIG_CHIP_M32102) || defined(CONFIG_CHIP_XNUX2) || \ 57 defined(CONFIG_CHIP_VDEC2) || defined(CONFIG_CHIP_M32700) || defined(CONFIG_CHIP_OPSP) \ 58 || defined(CONFIG_CHIP_M32104) 59#ifndef CONFIG_SMP 60 61 unsigned long count; 62 63 /* timer count may underflow right here */ 64 count = inl(M32R_MFT2CUT_PORTL); 65 66 if (inl(M32R_ICU_CR18_PORTL) & 0x00000100) /* underflow check */ 67 count = 0; 68 69 count = (latch - count) * TICK_SIZE; 70 elapsed_time = (count + latch / 2) / latch; 71 /* NOTE: LATCH is equal to the "interval" value (= reload count). */ 72 73#else /* CONFIG_SMP */ 74 unsigned long count; 75 static unsigned long p_jiffies = -1; 76 static unsigned long p_count = 0; 77 78 /* timer count may underflow right here */ 79 count = inl(M32R_MFT2CUT_PORTL); 80 81 if (jiffies == p_jiffies && count > p_count) 82 count = 0; 83 84 p_jiffies = jiffies; 85 p_count = count; 86 87 count = (latch - count) * TICK_SIZE; 88 elapsed_time = (count + latch / 2) / latch; 89 /* NOTE: LATCH is equal to the "interval" value (= reload count). */ 90#endif /* CONFIG_SMP */ 91#elif defined(CONFIG_CHIP_M32310) 92#warning do_gettimeoffse not implemented 93#else 94#error no chip configuration 95#endif 96 97 return elapsed_time; 98} 99 100/* 101 * This version of gettimeofday has near microsecond resolution. 102 */ 103void do_gettimeofday(struct timeval *tv) 104{ 105 unsigned long seq; 106 unsigned long usec, sec; 107 unsigned long max_ntp_tick = tick_usec - tickadj; 108 109 do { 110 seq = read_seqbegin(&xtime_lock); 111 112 usec = do_gettimeoffset(); 113 114 /* 115 * If time_adjust is negative then NTP is slowing the clock 116 * so make sure not to go into next possible interval. 117 * Better to lose some accuracy than have time go backwards.. 118 */ 119 if (unlikely(time_adjust < 0)) 120 usec = min(usec, max_ntp_tick); 121 122 sec = xtime.tv_sec; 123 usec += (xtime.tv_nsec / 1000); 124 } while (read_seqretry(&xtime_lock, seq)); 125 126 while (usec >= 1000000) { 127 usec -= 1000000; 128 sec++; 129 } 130 131 tv->tv_sec = sec; 132 tv->tv_usec = usec; 133} 134 135EXPORT_SYMBOL(do_gettimeofday); 136 137int do_settimeofday(struct timespec *tv) 138{ 139 time_t wtm_sec, sec = tv->tv_sec; 140 long wtm_nsec, nsec = tv->tv_nsec; 141 142 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) 143 return -EINVAL; 144 145 write_seqlock_irq(&xtime_lock); 146 /* 147 * This is revolting. We need to set "xtime" correctly. However, the 148 * value in this location is the value at the most recent update of 149 * wall time. Discover what correction gettimeofday() would have 150 * made, and then undo it! 151 */ 152 nsec -= do_gettimeoffset() * NSEC_PER_USEC; 153 154 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); 155 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); 156 157 set_normalized_timespec(&xtime, sec, nsec); 158 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); 159 160 ntp_clear(); 161 write_sequnlock_irq(&xtime_lock); 162 clock_was_set(); 163 164 return 0; 165} 166 167EXPORT_SYMBOL(do_settimeofday); 168 169/* 170 * In order to set the CMOS clock precisely, set_rtc_mmss has to be 171 * called 500 ms after the second nowtime has started, because when 172 * nowtime is written into the registers of the CMOS clock, it will 173 * jump to the next second precisely 500 ms later. Check the Motorola 174 * MC146818A or Dallas DS12887 data sheet for details. 175 * 176 * BUG: This routine does not handle hour overflow properly; it just 177 * sets the minutes. Usually you won't notice until after reboot! 178 */ 179static inline int set_rtc_mmss(unsigned long nowtime) 180{ 181 return 0; 182} 183 184/* last time the cmos clock got updated */ 185static long last_rtc_update = 0; 186 187/* 188 * timer_interrupt() needs to keep up the real-time clock, 189 * as well as call the "do_timer()" routine every clocktick 190 */ 191irqreturn_t timer_interrupt(int irq, void *dev_id) 192{ 193#ifndef CONFIG_SMP 194 profile_tick(CPU_PROFILING); 195#endif 196 do_timer(1); 197 198#ifndef CONFIG_SMP 199 update_process_times(user_mode(get_irq_regs())); 200#endif 201 /* 202 * If we have an externally synchronized Linux clock, then update 203 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be 204 * called as close as possible to 500 ms before the new second starts. 205 */ 206 write_seqlock(&xtime_lock); 207 if (ntp_synced() 208 && xtime.tv_sec > last_rtc_update + 660 209 && (xtime.tv_nsec / 1000) >= 500000 - ((unsigned)TICK_SIZE) / 2 210 && (xtime.tv_nsec / 1000) <= 500000 + ((unsigned)TICK_SIZE) / 2) 211 { 212 if (set_rtc_mmss(xtime.tv_sec) == 0) 213 last_rtc_update = xtime.tv_sec; 214 else /* do it again in 60 s */ 215 last_rtc_update = xtime.tv_sec - 600; 216 } 217 write_sequnlock(&xtime_lock); 218 /* As we return to user mode fire off the other CPU schedulers.. 219 this is basically because we don't yet share IRQ's around. 220 This message is rigged to be safe on the 386 - basically it's 221 a hack, so don't look closely for now.. */ 222 223#ifdef CONFIG_SMP 224 smp_local_timer_interrupt(); 225 smp_send_timer(); 226#endif 227 228 return IRQ_HANDLED; 229} 230 231struct irqaction irq0 = { timer_interrupt, IRQF_DISABLED, CPU_MASK_NONE, 232 "MFT2", NULL, NULL }; 233 234void __init time_init(void) 235{ 236 unsigned int epoch, year, mon, day, hour, min, sec; 237 238 sec = min = hour = day = mon = year = 0; 239 epoch = 0; 240 241 year = 23; 242 mon = 4; 243 day = 17; 244 245 /* Attempt to guess the epoch. This is the same heuristic as in rtc.c 246 so no stupid things will happen to timekeeping. Who knows, maybe 247 Ultrix also uses 1952 as epoch ... */ 248 if (year > 10 && year < 44) 249 epoch = 1980; 250 else if (year < 96) 251 epoch = 1952; 252 year += epoch; 253 254 xtime.tv_sec = mktime(year, mon, day, hour, min, sec); 255 xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ); 256 set_normalized_timespec(&wall_to_monotonic, 257 -xtime.tv_sec, -xtime.tv_nsec); 258 259#if defined(CONFIG_CHIP_M32102) || defined(CONFIG_CHIP_XNUX2) || \ 260 defined(CONFIG_CHIP_VDEC2) || defined(CONFIG_CHIP_M32700) || defined(CONFIG_CHIP_OPSP) \ 261 || defined(CONFIG_CHIP_M32104) 262 263 /* M32102 MFT setup */ 264 setup_irq(M32R_IRQ_MFT2, &irq0); 265 { 266 unsigned long bus_clock; 267 unsigned short divide; 268 269 bus_clock = boot_cpu_data.bus_clock; 270 divide = boot_cpu_data.timer_divide; 271 latch = (bus_clock/divide + HZ / 2) / HZ; 272 273 printk("Timer start : latch = %ld\n", latch); 274 275 outl((M32R_MFTMOD_CC_MASK | M32R_MFTMOD_TCCR \ 276 |M32R_MFTMOD_CSSEL011), M32R_MFT2MOD_PORTL); 277 outl(latch, M32R_MFT2RLD_PORTL); 278 outl(latch, M32R_MFT2CUT_PORTL); 279 outl(0, M32R_MFT2CMPRLD_PORTL); 280 outl((M32R_MFTCR_MFT2MSK|M32R_MFTCR_MFT2EN), M32R_MFTCR_PORTL); 281 } 282 283#elif defined(CONFIG_CHIP_M32310) 284#warning time_init not implemented 285#else 286#error no chip configuration 287#endif 288} 289