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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 | /* * 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/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 "time.h" static int nvram_as1 = NVRAM_AS1; static int nvram_as0 = NVRAM_AS0; static int nvram_data = NVRAM_DATA; __initfunc(void chrp_time_init(void)) { struct device_node *rtcs; int base; rtcs = find_compatible_devices("rtc", "pnpPNP,b00"); if (rtcs == NULL || rtcs->addrs == NULL) return; base = rtcs->addrs[0].address; nvram_as1 = 0; nvram_as0 = base; nvram_data = base + 1; } int 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_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_set_rtc_time(unsigned long nowtime) { unsigned char save_control, save_freq_select; struct rtc_time tm; 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; return 0; } unsigned long chrp_get_rtc_time(void) { unsigned int year, mon, day, hour, min, sec; int 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. */ /* read RTC exactly on falling edge of update flag */ for (i = 0 ; i < 1000000 ; i++) /* may take up to 1 second... */ if (chrp_cmos_clock_read(RTC_FREQ_SELECT) & RTC_UIP) break; for (i = 0 ; i < 1000000 ; i++) /* must try at least 2.228 ms */ if (!(chrp_cmos_clock_read(RTC_FREQ_SELECT) & RTC_UIP)) break; do { /* Isn't this overkill ? UIP above should guarantee consistency */ 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); } while (sec != chrp_cmos_clock_read(RTC_SECONDS)); 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); } __initfunc(void chrp_calibrate_decr(void)) { struct device_node *cpu; int freq, *fp, divisor; 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 = (int *) get_property(cpu, "timebase-frequency", NULL); if (fp != 0) freq = *fp; } freq *= 60; /* try to make freq/1e6 an integer */ divisor = 60; printk("time_init: decrementer frequency = %d/%d\n", freq, divisor); decrementer_count = freq / HZ / divisor; count_period_num = divisor; count_period_den = freq / 1000000; } |