FreeBSD/Linux Kernel Cross Reference
sys/dev/ic/mm58167.c
1 /* $NetBSD: mm58167.c,v 1.8 2006/09/04 23:45:30 gdamore 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 1.8 2006/09/04 23:45:30 gdamore 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, volatile struct timeval *);
57 int mm58167_settime(todr_chip_handle_t, volatile struct timeval *);
58
59 /*
60 * To quote SunOS's todreg.h:
61 * "This brain damaged chip insists on keeping the time in
62 * MM/DD HH:MM:SS format, even though it doesn't know about
63 * leap years and Feb. 29, thus making it nearly worthless."
64 */
65 #define mm58167_read(sc, r) bus_space_read_1(sc->mm58167_regt, sc->mm58167_regh, sc-> r)
66 #define mm58167_write(sc, r, v) bus_space_write_1(sc->mm58167_regt, sc->mm58167_regh, sc-> r, v)
67
68 todr_chip_handle_t
69 mm58167_attach(sc)
70 struct mm58167_softc *sc;
71 {
72 struct todr_chip_handle *handle;
73
74 printf(": mm58167");
75
76 handle = &sc->_mm58167_todr_handle;
77 memset(handle, 0, sizeof(handle));
78 handle->cookie = sc;
79 handle->todr_gettime = mm58167_gettime;
80 handle->todr_settime = mm58167_settime;
81 return (handle);
82 }
83
84 /*
85 * Set up the system's time, given a `reasonable' time value.
86 */
87 int
88 mm58167_gettime(handle, tv)
89 todr_chip_handle_t handle;
90 volatile struct timeval *tv;
91 {
92 struct mm58167_softc *sc = handle->cookie;
93 struct clock_ymdhms dt_hardware;
94 struct clock_ymdhms dt_reasonable;
95 int s;
96 u_int8_t byte_value;
97 int leap_year, had_leap_day;
98
99 /* First, read the date out of the chip. */
100
101 /* No interrupts while we're in the chip. */
102 s = splhigh();
103
104 /* Reset the status bit: */
105 byte_value = mm58167_read(sc, mm58167_status);
106
107 /*
108 * Read the date values until we get a coherent read (one
109 * where the status stays zero, indicating no increment was
110 * rippling through while we were reading).
111 */
112 do {
113 #define _MM58167_GET(dt_f, mm_f) byte_value = mm58167_read(sc, mm_f); dt_hardware.dt_f = FROMBCD(byte_value)
114 _MM58167_GET(dt_mon, mm58167_mon);
115 _MM58167_GET(dt_day, mm58167_day);
116 _MM58167_GET(dt_hour, mm58167_hour);
117 _MM58167_GET(dt_min, mm58167_min);
118 _MM58167_GET(dt_sec, mm58167_sec);
119 #undef _MM58167_GET
120 } while ((mm58167_read(sc, mm58167_status) & 1) == 0);
121
122 splx(s);
123
124 /* Convert the reasonable time into a date: */
125 clock_secs_to_ymdhms(tv->tv_sec, &dt_reasonable);
126
127 /*
128 * We need to fake a hardware year. if the hardware MM/DD
129 * HH:MM:SS date is less than the reasonable MM/DD
130 * HH:MM:SS, call it the reasonable year plus one, else call
131 * it the reasonable year.
132 */
133 if (dt_hardware.dt_mon < dt_reasonable.dt_mon ||
134 (dt_hardware.dt_mon == dt_reasonable.dt_mon &&
135 (dt_hardware.dt_day < dt_reasonable.dt_day ||
136 (dt_hardware.dt_day == dt_reasonable.dt_day &&
137 (dt_hardware.dt_hour < dt_reasonable.dt_hour ||
138 (dt_hardware.dt_hour == dt_reasonable.dt_hour &&
139 (dt_hardware.dt_min < dt_reasonable.dt_min ||
140 (dt_hardware.dt_min == dt_reasonable.dt_min &&
141 (dt_hardware.dt_sec < dt_reasonable.dt_sec))))))))) {
142 dt_hardware.dt_year = dt_reasonable.dt_year + 1;
143 } else {
144 dt_hardware.dt_year = dt_reasonable.dt_year;
145 }
146
147 /* convert the hardware date into a time: */
148 tv->tv_sec = clock_ymdhms_to_secs(&dt_hardware);
149 tv->tv_usec = 0;
150
151 /*
152 * Make a reasonable effort to see if a leap day has passed
153 * that we need to account for. This does the right thing
154 * only when the system was shut down before a leap day, and
155 * it is now after that leap day. It doesn't do the right
156 * thing when a leap day happened while the machine was last
157 * up. When that happens, the hardware clock becomes
158 * instantly wrong forever, until it gets fixed for some
159 * reason. Use NTP to deal.
160 */
161
162 /*
163 * This may have happened if the hardware says we're into
164 * March in the following year. Check that following year for
165 * a leap day.
166 */
167 if (dt_hardware.dt_year > dt_reasonable.dt_year &&
168 dt_hardware.dt_mon >= 3) {
169 leap_year = dt_hardware.dt_year;
170 }
171
172 /*
173 * This may have happened if the hardware says we're in the
174 * following year, and the system was shut down before March
175 * the previous year. check that previous year for a leap
176 * day.
177 */
178 else if (dt_hardware.dt_year > dt_reasonable.dt_year &&
179 dt_reasonable.dt_mon < 3) {
180 leap_year = dt_reasonable.dt_year;
181 }
182
183 /*
184 * This may have happened if the hardware says we're in the
185 * same year, but we weren't to March before, and we're in or
186 * past March now. Check this year for a leap day.
187 */
188 else if (dt_hardware.dt_year == dt_reasonable.dt_year
189 && dt_reasonable.dt_mon < 3
190 && dt_hardware.dt_mon >= 3) {
191 leap_year = dt_reasonable.dt_year;
192 }
193
194 /*
195 * Otherwise, no leap year to check.
196 */
197 else {
198 leap_year = 0;
199 }
200
201 /* Do the real leap day check. */
202 had_leap_day = 0;
203 if (leap_year > 0) {
204 if ((leap_year & 3) == 0) {
205 had_leap_day = 1;
206 if ((leap_year % 100) == 0) {
207 had_leap_day = 0;
208 if ((leap_year % 400) == 0)
209 had_leap_day = 1;
210 }
211 }
212 }
213
214 /*
215 * If we had a leap day, adjust the value we will return, and
216 * also update the hardware clock.
217 */
218 /*
219 * XXX - Since this update just writes back a corrected
220 * version of what we read out above, we lose whatever
221 * amount of time the clock has advanced since that read.
222 * Use NTP to deal.
223 */
224 if (had_leap_day) {
225 tv->tv_sec += SECDAY;
226 todr_settime(handle, tv);
227 }
228
229 return (0);
230 }
231
232 int
233 mm58167_settime(handle, tv)
234 todr_chip_handle_t handle;
235 volatile struct timeval *tv;
236 {
237 struct mm58167_softc *sc = handle->cookie;
238 struct clock_ymdhms dt_hardware;
239 int s;
240 u_int8_t byte_value;
241
242 /* Convert the seconds into ymdhms. */
243 clock_secs_to_ymdhms(tv->tv_sec, &dt_hardware);
244
245 /* No interrupts while we're in the chip. */
246 s = splhigh();
247
248 /*
249 * Issue a GO command to reset everything less significant
250 * than the minutes to zero.
251 */
252 mm58167_write(sc, mm58167_go, 0xFF);
253
254 /* Load everything. */
255 #define _MM58167_PUT(dt_f, mm_f) byte_value = TOBCD(dt_hardware.dt_f); mm58167_write(sc, mm_f, byte_value)
256 _MM58167_PUT(dt_mon, mm58167_mon);
257 _MM58167_PUT(dt_day, mm58167_day);
258 _MM58167_PUT(dt_hour, mm58167_hour);
259 _MM58167_PUT(dt_min, mm58167_min);
260 _MM58167_PUT(dt_sec, mm58167_sec);
261 #undef _MM58167_PUT
262
263 splx(s);
264 return (0);
265 }
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