FreeBSD/Linux Kernel Cross Reference
sys/dev/ic/mm58167.c
1 /* $NetBSD: mm58167.c,v 1.5 2005/02/27 00:27:02 perry 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 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the NetBSD
21 * Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 * contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38
39 /*
40 * National Semiconductor MM58167 time-of-day chip subroutines.
41 */
42
43 #include <sys/cdefs.h>
44 __KERNEL_RCSID(0, "$NetBSD: mm58167.c,v 1.5 2005/02/27 00:27:02 perry Exp $");
45
46 #include <sys/param.h>
47 #include <sys/malloc.h>
48 #include <sys/systm.h>
49 #include <sys/errno.h>
50 #include <sys/device.h>
51
52 #include <machine/bus.h>
53 #include <dev/clock_subr.h>
54 #include <dev/ic/mm58167var.h>
55
56 int mm58167_gettime(todr_chip_handle_t, struct timeval *);
57 int mm58167_settime(todr_chip_handle_t, struct timeval *);
58 int mm58167_getcal(todr_chip_handle_t, int *);
59 int mm58167_setcal(todr_chip_handle_t, int);
60
61 /*
62 * To quote SunOS's todreg.h:
63 * "This brain damaged chip insists on keeping the time in
64 * MM/DD HH:MM:SS format, even though it doesn't know about
65 * leap years and Feb. 29, thus making it nearly worthless."
66 */
67 #define mm58167_read(sc, r) bus_space_read_1(sc->mm58167_regt, sc->mm58167_regh, sc-> r)
68 #define mm58167_write(sc, r, v) bus_space_write_1(sc->mm58167_regt, sc->mm58167_regh, sc-> r, v)
69
70 todr_chip_handle_t
71 mm58167_attach(sc)
72 struct mm58167_softc *sc;
73 {
74 struct todr_chip_handle *handle;
75
76 printf(": mm58167");
77
78 handle = &sc->_mm58167_todr_handle;
79 memset(handle, 0, sizeof(handle));
80 handle->cookie = sc;
81 handle->todr_gettime = mm58167_gettime;
82 handle->todr_settime = mm58167_settime;
83 handle->todr_getcal = mm58167_getcal;
84 handle->todr_setcal = mm58167_setcal;
85 return (handle);
86 }
87
88 /*
89 * Set up the system's time, given a `reasonable' time value.
90 */
91 int
92 mm58167_gettime(handle, tv)
93 todr_chip_handle_t handle;
94 struct timeval *tv;
95 {
96 struct mm58167_softc *sc = handle->cookie;
97 struct clock_ymdhms dt_hardware;
98 struct clock_ymdhms dt_reasonable;
99 int s;
100 u_int8_t byte_value;
101 int leap_year, had_leap_day;
102
103 /* First, read the date out of the chip. */
104
105 /* No interrupts while we're in the chip. */
106 s = splhigh();
107
108 /* Reset the status bit: */
109 byte_value = mm58167_read(sc, mm58167_status);
110
111 /*
112 * Read the date values until we get a coherent read (one
113 * where the status stays zero, indicating no increment was
114 * rippling through while we were reading).
115 */
116 do {
117 #define _MM58167_GET(dt_f, mm_f) byte_value = mm58167_read(sc, mm_f); dt_hardware.dt_f = FROMBCD(byte_value)
118 _MM58167_GET(dt_mon, mm58167_mon);
119 _MM58167_GET(dt_day, mm58167_day);
120 _MM58167_GET(dt_hour, mm58167_hour);
121 _MM58167_GET(dt_min, mm58167_min);
122 _MM58167_GET(dt_sec, mm58167_sec);
123 #undef _MM58167_GET
124 } while ((mm58167_read(sc, mm58167_status) & 1) == 0);
125
126 splx(s);
127
128 /* Convert the reasonable time into a date: */
129 clock_secs_to_ymdhms(tv->tv_sec, &dt_reasonable);
130
131 /*
132 * We need to fake a hardware year. if the hardware MM/DD
133 * HH:MM:SS date is less than the reasonable MM/DD
134 * HH:MM:SS, call it the reasonable year plus one, else call
135 * it the reasonable year.
136 */
137 if (dt_hardware.dt_mon < dt_reasonable.dt_mon ||
138 (dt_hardware.dt_mon == dt_reasonable.dt_mon &&
139 (dt_hardware.dt_day < dt_reasonable.dt_day ||
140 (dt_hardware.dt_day == dt_reasonable.dt_day &&
141 (dt_hardware.dt_hour < dt_reasonable.dt_hour ||
142 (dt_hardware.dt_hour == dt_reasonable.dt_hour &&
143 (dt_hardware.dt_min < dt_reasonable.dt_min ||
144 (dt_hardware.dt_min == dt_reasonable.dt_min &&
145 (dt_hardware.dt_sec < dt_reasonable.dt_sec))))))))) {
146 dt_hardware.dt_year = dt_reasonable.dt_year + 1;
147 } else {
148 dt_hardware.dt_year = dt_reasonable.dt_year;
149 }
150
151 /* convert the hardware date into a time: */
152 tv->tv_sec = clock_ymdhms_to_secs(&dt_hardware);
153 tv->tv_usec = 0;
154
155 /*
156 * Make a reasonable effort to see if a leap day has passed
157 * that we need to account for. This does the right thing
158 * only when the system was shut down before a leap day, and
159 * it is now after that leap day. It doesn't do the right
160 * thing when a leap day happened while the machine was last
161 * up. When that happens, the hardware clock becomes
162 * instantly wrong forever, until it gets fixed for some
163 * reason. Use NTP to deal.
164 */
165
166 /*
167 * This may have happened if the hardware says we're into
168 * March in the following year. Check that following year for
169 * a leap day.
170 */
171 if (dt_hardware.dt_year > dt_reasonable.dt_year &&
172 dt_hardware.dt_mon >= 3) {
173 leap_year = dt_hardware.dt_year;
174 }
175
176 /*
177 * This may have happened if the hardware says we're in the
178 * following year, and the system was shut down before March
179 * the previous year. check that previous year for a leap
180 * day.
181 */
182 else if (dt_hardware.dt_year > dt_reasonable.dt_year &&
183 dt_reasonable.dt_mon < 3) {
184 leap_year = dt_reasonable.dt_year;
185 }
186
187 /*
188 * This may have happened if the hardware says we're in the
189 * same year, but we weren't to March before, and we're in or
190 * past March now. Check this year for a leap day.
191 */
192 else if (dt_hardware.dt_year == dt_reasonable.dt_year
193 && dt_reasonable.dt_mon < 3
194 && dt_hardware.dt_mon >= 3) {
195 leap_year = dt_reasonable.dt_year;
196 }
197
198 /*
199 * Otherwise, no leap year to check.
200 */
201 else {
202 leap_year = 0;
203 }
204
205 /* Do the real leap day check. */
206 had_leap_day = 0;
207 if (leap_year > 0) {
208 if ((leap_year & 3) == 0) {
209 had_leap_day = 1;
210 if ((leap_year % 100) == 0) {
211 had_leap_day = 0;
212 if ((leap_year % 400) == 0)
213 had_leap_day = 1;
214 }
215 }
216 }
217
218 /*
219 * If we had a leap day, adjust the value we will return, and
220 * also update the hardware clock.
221 */
222 /*
223 * XXX - Since this update just writes back a corrected
224 * version of what we read out above, we lose whatever
225 * amount of time the clock has advanced since that read.
226 * Use NTP to deal.
227 */
228 if (had_leap_day) {
229 tv->tv_sec += SECDAY;
230 todr_settime(handle, tv);
231 }
232
233 return (0);
234 }
235
236 int
237 mm58167_settime(handle, tv)
238 todr_chip_handle_t handle;
239 struct timeval *tv;
240 {
241 struct mm58167_softc *sc = handle->cookie;
242 struct clock_ymdhms dt_hardware;
243 int s;
244 u_int8_t byte_value;
245
246 /* Convert the seconds into ymdhms. */
247 clock_secs_to_ymdhms(tv->tv_sec, &dt_hardware);
248
249 /* No interrupts while we're in the chip. */
250 s = splhigh();
251
252 /*
253 * Issue a GO command to reset everything less significant
254 * than the minutes to zero.
255 */
256 mm58167_write(sc, mm58167_go, 0xFF);
257
258 /* Load everything. */
259 #define _MM58167_PUT(dt_f, mm_f) byte_value = TOBCD(dt_hardware.dt_f); mm58167_write(sc, mm_f, byte_value)
260 _MM58167_PUT(dt_mon, mm58167_mon);
261 _MM58167_PUT(dt_day, mm58167_day);
262 _MM58167_PUT(dt_hour, mm58167_hour);
263 _MM58167_PUT(dt_min, mm58167_min);
264 _MM58167_PUT(dt_sec, mm58167_sec);
265 #undef _MM58167_PUT
266
267 splx(s);
268 return (0);
269 }
270
271 int
272 mm58167_getcal(handle, vp)
273 todr_chip_handle_t handle;
274 int *vp;
275 {
276 return (EOPNOTSUPP);
277 }
278
279 int
280 mm58167_setcal(handle, v)
281 todr_chip_handle_t handle;
282 int v;
283 {
284 return (EOPNOTSUPP);
285 }
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