Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 | /* * BK Id: SCCS/s.chrp_time.c 1.7 05/17/01 18:14:21 cort */ /* * linux/arch/i386/kernel/time.c * * Copyright (C) 1991, 1992, 1995 Linus Torvalds * * Adapted for PowerPC (PreP) by Gary Thomas * Modified by Cort Dougan (cort@cs.nmt.edu) * copied and modified from intel version * */ #include <linux/errno.h> #include <linux/sched.h> #include <linux/kernel.h> #include <linux/param.h> #include <linux/string.h> #include <linux/mm.h> #include <linux/interrupt.h> #include <linux/time.h> #include <linux/timex.h> #include <linux/kernel_stat.h> #include <linux/mc146818rtc.h> #include <linux/init.h> #include <asm/segment.h> #include <asm/io.h> #include <asm/processor.h> #include <asm/nvram.h> #include <asm/prom.h> #include <asm/init.h> #include <asm/time.h> extern spinlock_t rtc_lock; static int nvram_as1 = NVRAM_AS1; static int nvram_as0 = NVRAM_AS0; static int nvram_data = NVRAM_DATA; long __init chrp_time_init(void) { struct device_node *rtcs; int base; rtcs = find_compatible_devices("rtc", "pnpPNP,b00"); if (rtcs == NULL || rtcs->addrs == NULL) return 0; base = rtcs->addrs[0].address; nvram_as1 = 0; nvram_as0 = base; nvram_data = base + 1; return 0; } int __chrp chrp_cmos_clock_read(int addr) { if (nvram_as1 != 0) outb(addr>>8, nvram_as1); outb(addr, nvram_as0); return (inb(nvram_data)); } void __chrp chrp_cmos_clock_write(unsigned long val, int addr) { if (nvram_as1 != 0) outb(addr>>8, nvram_as1); outb(addr, nvram_as0); outb(val, nvram_data); return; } /* * Set the hardware clock. -- Cort */ int __chrp chrp_set_rtc_time(unsigned long nowtime) { unsigned char save_control, save_freq_select; struct rtc_time tm; spin_lock(&rtc_lock); to_tm(nowtime, &tm); save_control = chrp_cmos_clock_read(RTC_CONTROL); /* tell the clock it's being set */ chrp_cmos_clock_write((save_control|RTC_SET), RTC_CONTROL); save_freq_select = chrp_cmos_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */ chrp_cmos_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT); tm.tm_year -= 1900; if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { BIN_TO_BCD(tm.tm_sec); BIN_TO_BCD(tm.tm_min); BIN_TO_BCD(tm.tm_hour); BIN_TO_BCD(tm.tm_mon); BIN_TO_BCD(tm.tm_mday); BIN_TO_BCD(tm.tm_year); } chrp_cmos_clock_write(tm.tm_sec,RTC_SECONDS); chrp_cmos_clock_write(tm.tm_min,RTC_MINUTES); chrp_cmos_clock_write(tm.tm_hour,RTC_HOURS); chrp_cmos_clock_write(tm.tm_mon,RTC_MONTH); chrp_cmos_clock_write(tm.tm_mday,RTC_DAY_OF_MONTH); chrp_cmos_clock_write(tm.tm_year,RTC_YEAR); /* The following flags have to be released exactly in this order, * otherwise the DS12887 (popular MC146818A clone with integrated * battery and quartz) will not reset the oscillator and will not * update precisely 500 ms later. You won't find this mentioned in * the Dallas Semiconductor data sheets, but who believes data * sheets anyway ... -- Markus Kuhn */ chrp_cmos_clock_write(save_control, RTC_CONTROL); chrp_cmos_clock_write(save_freq_select, RTC_FREQ_SELECT); if ( (time_state == TIME_ERROR) || (time_state == TIME_BAD) ) time_state = TIME_OK; spin_unlock(&rtc_lock); return 0; } unsigned long __chrp chrp_get_rtc_time(void) { unsigned int year, mon, day, hour, min, sec; int uip, i; /* The Linux interpretation of the CMOS clock register contents: * When the Update-In-Progress (UIP) flag goes from 1 to 0, the * RTC registers show the second which has precisely just started. * Let's hope other operating systems interpret the RTC the same way. */ /* Since the UIP flag is set for about 2.2 ms and the clock * is typically written with a precision of 1 jiffy, trying * to obtain a precision better than a few milliseconds is * an illusion. Only consistency is interesting, this also * allows to use the routine for /dev/rtc without a potential * 1 second kernel busy loop triggered by any reader of /dev/rtc. */ for ( i = 0; i<1000000; i++) { uip = chrp_cmos_clock_read(RTC_FREQ_SELECT); sec = chrp_cmos_clock_read(RTC_SECONDS); min = chrp_cmos_clock_read(RTC_MINUTES); hour = chrp_cmos_clock_read(RTC_HOURS); day = chrp_cmos_clock_read(RTC_DAY_OF_MONTH); mon = chrp_cmos_clock_read(RTC_MONTH); year = chrp_cmos_clock_read(RTC_YEAR); uip |= chrp_cmos_clock_read(RTC_FREQ_SELECT); if ((uip & RTC_UIP)==0) break; } if (!(chrp_cmos_clock_read(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { BCD_TO_BIN(sec); BCD_TO_BIN(min); BCD_TO_BIN(hour); BCD_TO_BIN(day); BCD_TO_BIN(mon); BCD_TO_BIN(year); } if ((year += 1900) < 1970) year += 100; return mktime(year, mon, day, hour, min, sec); } void __init chrp_calibrate_decr(void) { struct device_node *cpu; unsigned int freq, *fp; if (via_calibrate_decr()) return; /* * The cpu node should have a timebase-frequency property * to tell us the rate at which the decrementer counts. */ freq = 16666000; /* hardcoded default */ cpu = find_type_devices("cpu"); if (cpu != 0) { fp = (unsigned int *) get_property(cpu, "timebase-frequency", NULL); if (fp != 0) freq = *fp; } printk("time_init: decrementer frequency = %u.%.6u MHz\n", freq/1000000, freq%1000000); tb_ticks_per_jiffy = freq / HZ; tb_to_us = mulhwu_scale_factor(freq, 1000000); } |