1/*	$OpenBSD: time.c,v 1.19 2014/09/23 17:59:25 brad Exp $	*/
2
3/*
4 * Copyright (c) 1997 Michael Shalayeff
5 * Copyright (c) 1997 Tobias Weingartner
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS 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#include <sys/time.h>
32#include <machine/biosvar.h>
33#include <machine/pio.h>
34#include "libsa.h"
35#include "biosdev.h"
36
37#define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
38
39/*
40 * Convert from bcd (packed) to int
41 */
42static __inline u_int8_t
43bcdtoint(u_int8_t c)
44{
45	return ((c & 0xf0) / 8) * 5 + (c & 0x0f);
46}
47
48/*
49 * Quick compute of time in seconds since the Epoch
50 */
51const u_short monthcount[] = {
52	0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365
53};
54
55static __inline time_t
56compute(int year, u_int8_t month, u_int8_t day, u_int8_t hour,
57    u_int8_t min, u_int8_t sec)
58{
59	/* Number of days per month */
60	register time_t tt;
61
62	/* Compute days */
63	tt = (year - 1970) * 365 + monthcount[month] + day - 1;
64
65	/* Compute for leap year */
66	for (month <= 2 ? year-- : 0; year >= 1970; year--)
67		if (isleap(year))
68			tt++;
69
70	/* Plus the time */
71	tt = sec + 60 * (min + 60 * (tt * 24 + hour));
72
73	return tt;
74}
75
76static int
77bios_time_date(int f, u_int8_t *b)
78{
79	__asm volatile(DOINT(0x1a) "\n\t"
80	    "setc %b0\n\t"
81	    "movb %%ch, 0(%2)\n\t"
82	    "movb %%cl, 1(%2)\n\t"
83	    "movb %%dh, 2(%2)\n\t"
84	    "movb %%dl, 3(%2)\n\t"
85	    : "=a" (f)
86	    : "0" (f), "r" (b) : "%ecx", "%edx", "cc");
87
88	if (f & 0xff)
89		return -1;
90	else {
91		b[0] = bcdtoint(b[0]);
92		b[1] = bcdtoint(b[1]);
93		b[2] = bcdtoint(b[2]);
94		b[3] = bcdtoint(b[3]);
95		return 0;
96	}
97}
98
99static __inline int
100biosdate(u_int8_t *b)
101{
102	return bios_time_date(4 << 8, b);
103}
104
105static __inline int
106biostime(u_int8_t *b)
107{
108	return bios_time_date(2 << 8, b);
109}
110
111/*
112 * Return time since epoch
113 */
114time_t
115getsecs(void)
116{
117	u_int8_t timebuf[4], datebuf[4];
118
119	/* Query BIOS for time & date */
120	if (!biostime(timebuf) && !biosdate(datebuf)) {
121#ifdef notdef
122		int dst;
123
124		dst = timebuf[3];
125#endif
126		/* Convert to seconds since Epoch */
127		return compute(datebuf[0] * 100 + datebuf[1], datebuf[2],
128		    datebuf[3], timebuf[0], timebuf[1], timebuf[2]);
129	} else
130		errno = EIO;
131
132	return 1;
133}
134
135u_int
136sleep(u_int i)
137{
138	register time_t t;
139
140	/*
141	 * Loop for the requested number of seconds, polling BIOS,
142	 * so that it may handle interrupts.
143	 */
144	for (t = getsecs() + i; getsecs() < t; cnischar())
145		;
146
147	return 0;
148}
149