xref: /netbsd-src/sys/arch/x86/isa/rtc.c (revision 28b4250d7a034804d3ae4cd23d9a4546c63d4afe)
1 /*	$NetBSD: rtc.c,v 1.3 2025/01/07 22:37:13 jakllsch Exp $	*/
2 
3 /*-
4  * Copyright (c) 1990 The Regents of the University of California.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * William Jolitz and Don Ahn.
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. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *	@(#)clock.c	7.2 (Berkeley) 5/12/91
35  */
36 /*-
37  * Copyright (c) 1993, 1994 Charles M. Hannum.
38  *
39  * This code is derived from software contributed to Berkeley by
40  * William Jolitz and Don Ahn.
41  *
42  * Redistribution and use in source and binary forms, with or without
43  * modification, are permitted provided that the following conditions
44  * are met:
45  * 1. Redistributions of source code must retain the above copyright
46  *    notice, this list of conditions and the following disclaimer.
47  * 2. Redistributions in binary form must reproduce the above copyright
48  *    notice, this list of conditions and the following disclaimer in the
49  *    documentation and/or other materials provided with the distribution.
50  * 3. All advertising materials mentioning features or use of this software
51  *    must display the following acknowledgement:
52  *	This product includes software developed by the University of
53  *	California, Berkeley and its contributors.
54  * 4. Neither the name of the University nor the names of its contributors
55  *    may be used to endorse or promote products derived from this software
56  *    without specific prior written permission.
57  *
58  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
59  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
60  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
61  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
62  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
63  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
64  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
65  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
66  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
67  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
68  * SUCH DAMAGE.
69  *
70  *	@(#)clock.c	7.2 (Berkeley) 5/12/91
71  */
72 /*
73  * Mach Operating System
74  * Copyright (c) 1991,1990,1989 Carnegie Mellon University
75  * All Rights Reserved.
76  *
77  * Permission to use, copy, modify and distribute this software and its
78  * documentation is hereby granted, provided that both the copyright
79  * notice and this permission notice appear in all copies of the
80  * software, derivative works or modified versions, and any portions
81  * thereof, and that both notices appear in supporting documentation.
82  *
83  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
84  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
85  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
86  *
87  * Carnegie Mellon requests users of this software to return to
88  *
89  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
90  *  School of Computer Science
91  *  Carnegie Mellon University
92  *  Pittsburgh PA 15213-3890
93  *
94  * any improvements or extensions that they make and grant Carnegie Mellon
95  * the rights to redistribute these changes.
96  */
97 /*
98   Copyright 1988, 1989 by Intel Corporation, Santa Clara, California.
99 
100 		All Rights Reserved
101 
102 Permission to use, copy, modify, and distribute this software and
103 its documentation for any purpose and without fee is hereby
104 granted, provided that the above copyright notice appears in all
105 copies and that both the copyright notice and this permission notice
106 appear in supporting documentation, and that the name of Intel
107 not be used in advertising or publicity pertaining to distribution
108 of the software without specific, written prior permission.
109 
110 INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
111 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
112 IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
113 CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
114 LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
115 NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
116 WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
117 */
118 
119 /*
120  * Primitive RTC chip routines.
121  */
122 
123 #include <sys/cdefs.h>
124 __KERNEL_RCSID(0, "$NetBSD: rtc.c,v 1.3 2025/01/07 22:37:13 jakllsch Exp $");
125 
126 #include <sys/param.h>
127 #include <sys/systm.h>
128 #include <sys/time.h>
129 #include <sys/timetc.h>
130 #include <sys/kernel.h>
131 
132 #include <dev/isa/isareg.h>
133 #include <dev/isa/isavar.h>
134 #include <i386/isa/nvram.h>
135 
136 #include <machine/pio.h>
137 
138 #include <dev/ic/mc146818reg.h>
139 #include <x86/rtc.h>
140 
141 #ifndef __x86_64__
142 #include "mca.h"
143 #endif
144 #if NMCA > 0
145 #include <machine/mca_machdep.h>	/* for MCA_system */
146 #endif
147 
148 #include "acpica.h"
149 #if NACPICA > 0
150 #include <dev/acpi/acpivar.h>
151 #endif
152 
153 static void	rtcinit(void);
154 static int	rtcget(mc_todregs *);
155 static void	rtcput(mc_todregs *);
156 static int	cmoscheck(void);
157 static int	clock_expandyear(int);
158 
159 /* XXX use sc? */
160 u_int
161 mc146818_read(void *sc, u_int reg)
162 {
163 
164 	outb(IO_RTC, reg);
165 	return (inb(IO_RTC+1));
166 }
167 
168 void
169 mc146818_write(void *sc, u_int reg, u_int datum)
170 {
171 
172 	outb(IO_RTC, reg);
173 	outb(IO_RTC+1, datum);
174 }
175 
176 static void
177 rtcinit(void)
178 {
179 	static int first_rtcopen_ever = 1;
180 
181 	if (!first_rtcopen_ever)
182 		return;
183 	first_rtcopen_ever = 0;
184 
185 	mc146818_write(NULL, MC_REGA,			/* XXX softc */
186 	    MC_BASE_32_KHz | MC_RATE_1024_Hz);
187 	mc146818_write(NULL, MC_REGB, MC_REGB_24HR);	/* XXX softc */
188 }
189 
190 static int
191 rtcget(mc_todregs *regs)
192 {
193 
194 	rtcinit();
195 	if ((mc146818_read(NULL, MC_REGD) & MC_REGD_VRT) == 0) /* XXX softc */
196 		return (-1);
197 	MC146818_GETTOD(NULL, regs);			/* XXX softc */
198 	return (0);
199 }
200 
201 static void
202 rtcput(mc_todregs *regs)
203 {
204 
205 	rtcinit();
206 	MC146818_PUTTOD(NULL, regs);			/* XXX softc */
207 }
208 
209 /*
210  * check whether the CMOS layout is "standard"-like (ie, not PS/2-like),
211  * to be called at splclock()
212  */
213 static int
214 cmoscheck(void)
215 {
216 	int i;
217 	unsigned short cksum = 0;
218 
219 	for (i = 0x10; i <= 0x2d; i++)
220 		cksum += mc146818_read(NULL, i); /* XXX softc */
221 
222 	return (cksum == (mc146818_read(NULL, 0x2e) << 8)
223 			  + mc146818_read(NULL, 0x2f));
224 }
225 
226 #if NMCA > 0
227 /*
228  * Check whether the CMOS layout is PS/2 like, to be called at splclock().
229  */
230 static int cmoscheckps2(void);
231 static int
232 cmoscheckps2(void)
233 {
234 #if 0
235 	/* Disabled until I find out the CRC checksum algorithm IBM uses */
236 	int i;
237 	unsigned short cksum = 0;
238 
239 	for (i = 0x10; i <= 0x31; i++)
240 		cksum += mc146818_read(NULL, i); /* XXX softc */
241 
242 	return (cksum == (mc146818_read(NULL, 0x32) << 8)
243 			  + mc146818_read(NULL, 0x33));
244 #else
245 	/* Check 'incorrect checksum' bit of IBM PS/2 Diagnostic Status Byte */
246 	return ((mc146818_read(NULL, NVRAM_DIAG) & (1<<6)) == 0);
247 #endif
248 }
249 #endif /* NMCA > 0 */
250 
251 /*
252  * patchable to control century byte handling:
253  * 1: always update
254  * -1: never touch
255  * 0: try to figure out itself
256  */
257 int rtc_update_century = 0;
258 
259 /*
260  * Expand a two-digit year as read from the clock chip
261  * into full width.
262  * Being here, deal with the CMOS century byte.
263  */
264 static int centb = NVRAM_CENTURY;
265 static int
266 clock_expandyear(int clockyear)
267 {
268 	int s, clockcentury, cmoscentury;
269 
270 	clockcentury = (clockyear < 70) ? 20 : 19;
271 	clockyear += 100 * clockcentury;
272 
273 	if (rtc_update_century < 0)
274 		return (clockyear);
275 
276 	s = splclock();
277 #if NACPICA > 0
278 	if (acpi_active && AcpiGbl_FADT.Century >= MC_NVRAM_START &&
279 	    AcpiGbl_FADT.Century < (MC_NVRAM_START + MC_NVRAM_SIZE))
280 		cmoscentury = mc146818_read(NULL,
281 		    (centb = AcpiGbl_FADT.Century));
282 	else
283 #endif
284 	if (cmoscheck())
285 		cmoscentury = mc146818_read(NULL, NVRAM_CENTURY);
286 #if NMCA > 0
287 	else if (MCA_system && cmoscheckps2())
288 		cmoscentury = mc146818_read(NULL, (centb = 0x37));
289 #endif
290 	else
291 		cmoscentury = 0;
292 	splx(s);
293 	if (!cmoscentury) {
294 #ifdef DIAGNOSTIC
295 		printf("clock: unknown CMOS layout\n");
296 #endif
297 		return (clockyear);
298 	}
299 	cmoscentury = bcdtobin(cmoscentury);
300 
301 	if (cmoscentury != clockcentury) {
302 		/* XXX note: saying "century is 20" might confuse the naive. */
303 		printf("WARNING: NVRAM century is %d but RTC year is %d\n",
304 		       cmoscentury, clockyear);
305 
306 		/* Kludge to roll over century. */
307 		if ((rtc_update_century > 0) ||
308 		    ((cmoscentury == 19) && (clockcentury == 20) &&
309 		     (clockyear == 2000))) {
310 			printf("WARNING: Setting NVRAM century to %d\n",
311 			       clockcentury);
312 			s = splclock();
313 			mc146818_write(NULL, centb, bintobcd(clockcentury));
314 			splx(s);
315 		}
316 	} else if (cmoscentury == 19 && rtc_update_century == 0)
317 		rtc_update_century = 1; /* will update later in resettodr() */
318 
319 	return (clockyear);
320 }
321 
322 int
323 rtc_get_ymdhms(todr_chip_handle_t tch, struct clock_ymdhms *dt)
324 {
325 	int s;
326 	mc_todregs rtclk;
327 
328 	s = splclock();
329 	if (rtcget(&rtclk)) {
330 		splx(s);
331 		return -1;
332 	}
333 	splx(s);
334 
335 	dt->dt_sec = bcdtobin(rtclk[MC_SEC]);
336 	dt->dt_min = bcdtobin(rtclk[MC_MIN]);
337 	dt->dt_hour = bcdtobin(rtclk[MC_HOUR]);
338 	dt->dt_day = bcdtobin(rtclk[MC_DOM]);
339 	dt->dt_mon = bcdtobin(rtclk[MC_MONTH]);
340 	dt->dt_year = clock_expandyear(bcdtobin(rtclk[MC_YEAR]));
341 
342 	return 0;
343 }
344 
345 int
346 rtc_set_ymdhms(todr_chip_handle_t tch, struct clock_ymdhms *dt)
347 {
348 	mc_todregs rtclk;
349 	int century;
350 	int s;
351 
352 	s = splclock();
353 	if (rtcget(&rtclk))
354 		memset(&rtclk, 0, sizeof(rtclk));
355 	splx(s);
356 
357 	rtclk[MC_SEC] = bintobcd(dt->dt_sec);
358 	rtclk[MC_MIN] = bintobcd(dt->dt_min);
359 	rtclk[MC_HOUR] = bintobcd(dt->dt_hour);
360 	rtclk[MC_DOW] = dt->dt_wday + 1;
361 	rtclk[MC_YEAR] = bintobcd(dt->dt_year % 100);
362 	rtclk[MC_MONTH] = bintobcd(dt->dt_mon);
363 	rtclk[MC_DOM] = bintobcd(dt->dt_day);
364 
365 #ifdef DEBUG_CLOCK
366 	printf("setclock: %x/%x/%x %x:%x:%x\n", rtclk[MC_YEAR], rtclk[MC_MONTH],
367 	   rtclk[MC_DOM], rtclk[MC_HOUR], rtclk[MC_MIN], rtclk[MC_SEC]);
368 #endif
369 	s = splclock();
370 	rtcput(&rtclk);
371 	if (rtc_update_century > 0) {
372 		century = bintobcd(dt->dt_year / 100);
373 		mc146818_write(NULL, centb, century); /* XXX softc */
374 	}
375 	splx(s);
376 	return 0;
377 
378 }
379 
380 void
381 rtc_register(void)
382 {
383 	static struct todr_chip_handle	tch;
384 	tch.todr_gettime_ymdhms = rtc_get_ymdhms;
385 	tch.todr_settime_ymdhms = rtc_set_ymdhms;
386 	tch.todr_setwen = NULL;
387 
388 	todr_attach(&tch);
389 }
390 
391