Annotation of prex/dev/i386/pc/rtc.c, Revision 1.1.1.1
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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