mm58167.c revision 1.9.20.1 1 /* $NetBSD: mm58167.c,v 1.9.20.1 2008/05/16 02:24:05 yamt Exp $ */
2
3 /*
4 * Copyright (c) 2001 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Matthew Fredette.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 /*
33 * National Semiconductor MM58167 time-of-day chip subroutines.
34 */
35
36 #include <sys/cdefs.h>
37 __KERNEL_RCSID(0, "$NetBSD: mm58167.c,v 1.9.20.1 2008/05/16 02:24:05 yamt Exp $");
38
39 #include <sys/param.h>
40 #include <sys/malloc.h>
41 #include <sys/systm.h>
42 #include <sys/errno.h>
43 #include <sys/device.h>
44
45 #include <sys/bus.h>
46 #include <dev/clock_subr.h>
47 #include <dev/ic/mm58167var.h>
48
49 int mm58167_gettime(todr_chip_handle_t, volatile struct timeval *);
50 int mm58167_settime(todr_chip_handle_t, volatile struct timeval *);
51
52 /*
53 * To quote SunOS's todreg.h:
54 * "This brain damaged chip insists on keeping the time in
55 * MM/DD HH:MM:SS format, even though it doesn't know about
56 * leap years and Feb. 29, thus making it nearly worthless."
57 */
58 #define mm58167_read(sc, r) bus_space_read_1(sc->mm58167_regt, sc->mm58167_regh, sc-> r)
59 #define mm58167_write(sc, r, v) bus_space_write_1(sc->mm58167_regt, sc->mm58167_regh, sc-> r, v)
60
61 todr_chip_handle_t
62 mm58167_attach(sc)
63 struct mm58167_softc *sc;
64 {
65 struct todr_chip_handle *handle;
66
67 printf(": mm58167");
68
69 handle = &sc->_mm58167_todr_handle;
70 memset(handle, 0, sizeof(handle));
71 handle->cookie = sc;
72 handle->todr_gettime = mm58167_gettime;
73 handle->todr_settime = mm58167_settime;
74 return (handle);
75 }
76
77 /*
78 * Set up the system's time, given a `reasonable' time value.
79 */
80 int
81 mm58167_gettime(handle, tv)
82 todr_chip_handle_t handle;
83 volatile struct timeval *tv;
84 {
85 struct mm58167_softc *sc = handle->cookie;
86 struct clock_ymdhms dt_hardware;
87 struct clock_ymdhms dt_reasonable;
88 int s;
89 u_int8_t byte_value;
90 int leap_year, had_leap_day;
91
92 /* First, read the date out of the chip. */
93
94 /* No interrupts while we're in the chip. */
95 s = splhigh();
96
97 /* Reset the status bit: */
98 byte_value = mm58167_read(sc, mm58167_status);
99
100 /*
101 * Read the date values until we get a coherent read (one
102 * where the status stays zero, indicating no increment was
103 * rippling through while we were reading).
104 */
105 do {
106 #define _MM58167_GET(dt_f, mm_f) byte_value = mm58167_read(sc, mm_f); dt_hardware.dt_f = FROMBCD(byte_value)
107 _MM58167_GET(dt_mon, mm58167_mon);
108 _MM58167_GET(dt_day, mm58167_day);
109 _MM58167_GET(dt_hour, mm58167_hour);
110 _MM58167_GET(dt_min, mm58167_min);
111 _MM58167_GET(dt_sec, mm58167_sec);
112 #undef _MM58167_GET
113 } while ((mm58167_read(sc, mm58167_status) & 1) == 0);
114
115 splx(s);
116
117 /* Convert the reasonable time into a date: */
118 clock_secs_to_ymdhms(tv->tv_sec, &dt_reasonable);
119
120 /*
121 * We need to fake a hardware year. if the hardware MM/DD
122 * HH:MM:SS date is less than the reasonable MM/DD
123 * HH:MM:SS, call it the reasonable year plus one, else call
124 * it the reasonable year.
125 */
126 if (dt_hardware.dt_mon < dt_reasonable.dt_mon ||
127 (dt_hardware.dt_mon == dt_reasonable.dt_mon &&
128 (dt_hardware.dt_day < dt_reasonable.dt_day ||
129 (dt_hardware.dt_day == dt_reasonable.dt_day &&
130 (dt_hardware.dt_hour < dt_reasonable.dt_hour ||
131 (dt_hardware.dt_hour == dt_reasonable.dt_hour &&
132 (dt_hardware.dt_min < dt_reasonable.dt_min ||
133 (dt_hardware.dt_min == dt_reasonable.dt_min &&
134 (dt_hardware.dt_sec < dt_reasonable.dt_sec))))))))) {
135 dt_hardware.dt_year = dt_reasonable.dt_year + 1;
136 } else {
137 dt_hardware.dt_year = dt_reasonable.dt_year;
138 }
139
140 /* convert the hardware date into a time: */
141 tv->tv_sec = clock_ymdhms_to_secs(&dt_hardware);
142 tv->tv_usec = 0;
143
144 /*
145 * Make a reasonable effort to see if a leap day has passed
146 * that we need to account for. This does the right thing
147 * only when the system was shut down before a leap day, and
148 * it is now after that leap day. It doesn't do the right
149 * thing when a leap day happened while the machine was last
150 * up. When that happens, the hardware clock becomes
151 * instantly wrong forever, until it gets fixed for some
152 * reason. Use NTP to deal.
153 */
154
155 /*
156 * This may have happened if the hardware says we're into
157 * March in the following year. Check that following year for
158 * a leap day.
159 */
160 if (dt_hardware.dt_year > dt_reasonable.dt_year &&
161 dt_hardware.dt_mon >= 3) {
162 leap_year = dt_hardware.dt_year;
163 }
164
165 /*
166 * This may have happened if the hardware says we're in the
167 * following year, and the system was shut down before March
168 * the previous year. check that previous year for a leap
169 * day.
170 */
171 else if (dt_hardware.dt_year > dt_reasonable.dt_year &&
172 dt_reasonable.dt_mon < 3) {
173 leap_year = dt_reasonable.dt_year;
174 }
175
176 /*
177 * This may have happened if the hardware says we're in the
178 * same year, but we weren't to March before, and we're in or
179 * past March now. Check this year for a leap day.
180 */
181 else if (dt_hardware.dt_year == dt_reasonable.dt_year
182 && dt_reasonable.dt_mon < 3
183 && dt_hardware.dt_mon >= 3) {
184 leap_year = dt_reasonable.dt_year;
185 }
186
187 /*
188 * Otherwise, no leap year to check.
189 */
190 else {
191 leap_year = 0;
192 }
193
194 /* Do the real leap day check. */
195 had_leap_day = 0;
196 if (leap_year > 0) {
197 if ((leap_year & 3) == 0) {
198 had_leap_day = 1;
199 if ((leap_year % 100) == 0) {
200 had_leap_day = 0;
201 if ((leap_year % 400) == 0)
202 had_leap_day = 1;
203 }
204 }
205 }
206
207 /*
208 * If we had a leap day, adjust the value we will return, and
209 * also update the hardware clock.
210 */
211 /*
212 * XXX - Since this update just writes back a corrected
213 * version of what we read out above, we lose whatever
214 * amount of time the clock has advanced since that read.
215 * Use NTP to deal.
216 */
217 if (had_leap_day) {
218 tv->tv_sec += SECDAY;
219 todr_settime(handle, tv);
220 }
221
222 return (0);
223 }
224
225 int
226 mm58167_settime(handle, tv)
227 todr_chip_handle_t handle;
228 volatile struct timeval *tv;
229 {
230 struct mm58167_softc *sc = handle->cookie;
231 struct clock_ymdhms dt_hardware;
232 int s;
233 u_int8_t byte_value;
234
235 /* Convert the seconds into ymdhms. */
236 clock_secs_to_ymdhms(tv->tv_sec, &dt_hardware);
237
238 /* No interrupts while we're in the chip. */
239 s = splhigh();
240
241 /*
242 * Issue a GO command to reset everything less significant
243 * than the minutes to zero.
244 */
245 mm58167_write(sc, mm58167_go, 0xFF);
246
247 /* Load everything. */
248 #define _MM58167_PUT(dt_f, mm_f) byte_value = TOBCD(dt_hardware.dt_f); mm58167_write(sc, mm_f, byte_value)
249 _MM58167_PUT(dt_mon, mm58167_mon);
250 _MM58167_PUT(dt_day, mm58167_day);
251 _MM58167_PUT(dt_hour, mm58167_hour);
252 _MM58167_PUT(dt_min, mm58167_min);
253 _MM58167_PUT(dt_sec, mm58167_sec);
254 #undef _MM58167_PUT
255
256 splx(s);
257 return (0);
258 }
259