Annotation of prex/dev/i386/pc/rtc.c, Revision 1.1
1.1 ! nbrk 1: /*-
! 2: * Copyright (c) 2005, Kohsuke Ohtani
! 3: * All rights reserved.
! 4: *
! 5: * Redistribution and use in source and binary forms, with or without
! 6: * modification, are permitted provided that the following conditions
! 7: * are met:
! 8: * 1. Redistributions of source code must retain the above copyright
! 9: * notice, this list of conditions and the following disclaimer.
! 10: * 2. Redistributions in binary form must reproduce the above copyright
! 11: * notice, this list of conditions and the following disclaimer in the
! 12: * documentation and/or other materials provided with the distribution.
! 13: * 3. Neither the name of the author nor the names of any co-contributors
! 14: * may be used to endorse or promote products derived from this software
! 15: * without specific prior written permission.
! 16: *
! 17: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
! 18: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 19: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 20: * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
! 21: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 22: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 23: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 24: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 25: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 26: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 27: * SUCH DAMAGE.
! 28: */
! 29:
! 30: /*
! 31: * rtc.c - Real time clock driver
! 32: */
! 33:
! 34: #include <sys/time.h>
! 35: #include <sys/ioctl.h>
! 36:
! 37: #include <driver.h>
! 38: #include <cpufunc.h>
! 39:
! 40: /* Cmos */
! 41: #define CMOS_INDEX 0x70
! 42: #define CMOS_DATA 0x71
! 43:
! 44: /* CMOS address */
! 45: #define CMOS_SEC 0x00
! 46: #define CMOS_MIN 0x02
! 47: #define CMOS_HOUR 0x04
! 48: #define CMOS_DAY 0x07
! 49: #define CMOS_MON 0x08
! 50: #define CMOS_YEAR 0x09
! 51: #define CMOS_STS_A 0x0a
! 52: #define CMOS_UIP 0x80
! 53: #define CMOS_STS_B 0x0b
! 54: #define CMOS_BCD 0x04
! 55:
! 56:
! 57: #define DAYSPERYEAR (31+28+31+30+31+30+31+31+30+31+30+31)
! 58:
! 59: static int rtc_read(device_t dev, char *buf, size_t *nbyte, int blkno);
! 60: static int rtc_ioctl(device_t dev, u_long cmd, void *arg);
! 61: static int rtc_init(void);
! 62:
! 63: /*
! 64: * Driver structure
! 65: */
! 66: struct driver rtc_drv = {
! 67: /* name */ "Realtime Clock",
! 68: /* order */ 4,
! 69: /* init */ rtc_init,
! 70: };
! 71:
! 72: /*
! 73: * Device I/O table
! 74: */
! 75: static struct devio rtc_io = {
! 76: /* open */ NULL,
! 77: /* close */ NULL,
! 78: /* read */ rtc_read,
! 79: /* write */ NULL,
! 80: /* ioctl */ rtc_ioctl,
! 81: /* event */ NULL,
! 82: };
! 83:
! 84: static const int daysinmonth[] =
! 85: { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
! 86:
! 87: static device_t rtc_dev; /* Device object */
! 88: static u_long boot_sec; /* Time (sec) at system boot */
! 89: static u_long boot_ticks; /* Time (ticks) at system boot */
! 90:
! 91:
! 92: static u_int
! 93: cmos_read(int index)
! 94: {
! 95: u_int value;
! 96:
! 97: irq_lock();
! 98: outb(index, CMOS_INDEX);
! 99: value = inb(CMOS_DATA);
! 100: irq_unlock();
! 101: return value;
! 102: }
! 103:
! 104: /*
! 105: static void
! 106: cmos_write(int index, int value)
! 107: {
! 108: irq_lock();
! 109: outb(index, CMOS_INDEX);
! 110: outb(value, CMOS_DATA);
! 111: irq_unlock();
! 112: }
! 113: */
! 114:
! 115: static u_int
! 116: bcd2bin(u_int bcd)
! 117: {
! 118:
! 119: return (bcd & 0x0f) + ((bcd >> 4) & 0xf) * 10;
! 120: }
! 121:
! 122: /*
! 123: static int bin2bcd(int bin)
! 124: {
! 125: return ((bin / 10) << 4) + (bin % 10);
! 126: }
! 127: */
! 128:
! 129: static int
! 130: is_leap(u_int year)
! 131: {
! 132:
! 133: if ((year % 4 == 0) && (year % 100 != 0))
! 134: return 1;
! 135: if (year % 400 == 0)
! 136: return 1;
! 137: return 0;
! 138: }
! 139:
! 140: /*
! 141: * Return current seconds (seconds since Epoch 1970/1/1 0:0:0)
! 142: */
! 143: static u_long
! 144: cmos_gettime(void)
! 145: {
! 146: u_int sec, min, hour, day, mon, year;
! 147: u_int i;
! 148: u_int days;
! 149:
! 150: /* Wait until data ready */
! 151: for (i = 0; i < 1000000; i++)
! 152: if (!(cmos_read(CMOS_STS_A) & CMOS_UIP))
! 153: break;
! 154:
! 155: sec = cmos_read(CMOS_SEC);
! 156: min = cmos_read(CMOS_MIN);
! 157: hour = cmos_read(CMOS_HOUR);
! 158: day = cmos_read(CMOS_DAY);
! 159: mon = cmos_read(CMOS_MON);
! 160: year = cmos_read(CMOS_YEAR);
! 161:
! 162: if (!(cmos_read(CMOS_STS_B) & CMOS_BCD)) {
! 163: sec = bcd2bin(sec);
! 164: min = bcd2bin(min);
! 165: hour = bcd2bin(hour);
! 166: day = bcd2bin(day);
! 167: mon = bcd2bin(mon);
! 168: year = bcd2bin(year);
! 169: }
! 170: if (year < 80)
! 171: year += 2000;
! 172: else
! 173: year += 1900;
! 174: #ifdef DEBUG
! 175: printf("rtc: system time was %d/%d/%d %d:%d:%d\n",
! 176: year, mon, day, hour, min, sec);
! 177: #endif
! 178:
! 179: days = 0;
! 180: for (i = 1970; i < year; i++)
! 181: days += DAYSPERYEAR + is_leap(i);
! 182: for (i = 1; i < mon; i++)
! 183: days += daysinmonth[i - 1];
! 184: if ((mon > 2) && is_leap(year))
! 185: days++;
! 186: days += day - 1;
! 187:
! 188: sec = (((days * 24 + hour) * 60) + min) * 60 + sec;
! 189: return sec;
! 190: }
! 191:
! 192: static int
! 193: rtc_read(device_t dev, char *buf, size_t *nbyte, int blkno)
! 194: {
! 195: u_long time;
! 196:
! 197: if (*nbyte < sizeof(u_long))
! 198: return 0;
! 199:
! 200: time = cmos_gettime();
! 201: if (umem_copyout(&time, buf, sizeof(u_long)))
! 202: return EFAULT;
! 203: *nbyte = sizeof(u_long);
! 204: return 0;
! 205: }
! 206:
! 207: static int
! 208: rtc_ioctl(device_t dev, u_long cmd, void *arg)
! 209: {
! 210: struct timeval tv;
! 211: int err = 0;
! 212: u_long msec;
! 213:
! 214: switch (cmd) {
! 215: case RTCIOC_GET_TIME:
! 216: /*
! 217: * Calculate current time (sec/usec) from
! 218: * boot time and current tick count.
! 219: */
! 220: msec = tick_to_msec(timer_count() - boot_ticks);
! 221: tv.tv_sec = (long)(boot_sec + (msec / 1000));
! 222: tv.tv_usec = (long)((msec * 1000) % 1000000);
! 223: if (umem_copyout(&tv, arg, sizeof(tv)))
! 224: return EFAULT;
! 225: break;
! 226: case RTCIOC_SET_TIME:
! 227: err = EINVAL;
! 228: break;
! 229: default:
! 230: return EINVAL;
! 231: }
! 232: return err;
! 233: }
! 234:
! 235: /*
! 236: * Initialize
! 237: */
! 238: static int
! 239: rtc_init(void)
! 240: {
! 241:
! 242: /* Create device object */
! 243: rtc_dev = device_create(&rtc_io, "rtc", DF_CHR);
! 244: ASSERT(rtc_dev);
! 245: boot_sec = cmos_gettime();
! 246: boot_ticks = timer_count();
! 247: return 0;
! 248: }
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