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1/*
2 * RTC class driver for "CMOS RTC": PCs, ACPI, etc
3 *
4 * Copyright (C) 1996 Paul Gortmaker (drivers/char/rtc.c)
5 * Copyright (C) 2006 David Brownell (convert to new framework)
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 */
12
13/*
14 * The original "cmos clock" chip was an MC146818 chip, now obsolete.
15 * That defined the register interface now provided by all PCs, some
16 * non-PC systems, and incorporated into ACPI. Modern PC chipsets
17 * integrate an MC146818 clone in their southbridge, and boards use
18 * that instead of discrete clones like the DS12887 or M48T86. There
19 * are also clones that connect using the LPC bus.
20 *
21 * That register API is also used directly by various other drivers
22 * (notably for integrated NVRAM), infrastructure (x86 has code to
23 * bypass the RTC framework, directly reading the RTC during boot
24 * and updating minutes/seconds for systems using NTP synch) and
25 * utilities (like userspace 'hwclock', if no /dev node exists).
26 *
27 * So **ALL** calls to CMOS_READ and CMOS_WRITE must be done with
28 * interrupts disabled, holding the global rtc_lock, to exclude those
29 * other drivers and utilities on correctly configured systems.
30 */
31
32#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33
34#include <linux/kernel.h>
35#include <linux/module.h>
36#include <linux/init.h>
37#include <linux/interrupt.h>
38#include <linux/spinlock.h>
39#include <linux/platform_device.h>
40#include <linux/log2.h>
41#include <linux/pm.h>
42#include <linux/of.h>
43#include <linux/of_platform.h>
44#ifdef CONFIG_X86
45#include <asm/i8259.h>
46#endif
47
48/* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
49#include <linux/mc146818rtc.h>
50
51struct cmos_rtc {
52 struct rtc_device *rtc;
53 struct device *dev;
54 int irq;
55 struct resource *iomem;
56 time64_t alarm_expires;
57
58 void (*wake_on)(struct device *);
59 void (*wake_off)(struct device *);
60
61 u8 enabled_wake;
62 u8 suspend_ctrl;
63
64 /* newer hardware extends the original register set */
65 u8 day_alrm;
66 u8 mon_alrm;
67 u8 century;
68
69 struct rtc_wkalrm saved_wkalrm;
70};
71
72/* both platform and pnp busses use negative numbers for invalid irqs */
73#define is_valid_irq(n) ((n) > 0)
74
75static const char driver_name[] = "rtc_cmos";
76
77/* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
78 * always mask it against the irq enable bits in RTC_CONTROL. Bit values
79 * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
80 */
81#define RTC_IRQMASK (RTC_PF | RTC_AF | RTC_UF)
82
83static inline int is_intr(u8 rtc_intr)
84{
85 if (!(rtc_intr & RTC_IRQF))
86 return 0;
87 return rtc_intr & RTC_IRQMASK;
88}
89
90/*----------------------------------------------------------------*/
91
92/* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
93 * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
94 * used in a broken "legacy replacement" mode. The breakage includes
95 * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
96 * other (better) use.
97 *
98 * When that broken mode is in use, platform glue provides a partial
99 * emulation of hardware RTC IRQ facilities using HPET #1. We don't
100 * want to use HPET for anything except those IRQs though...
101 */
102#ifdef CONFIG_HPET_EMULATE_RTC
103#include <asm/hpet.h>
104#else
105
106static inline int is_hpet_enabled(void)
107{
108 return 0;
109}
110
111static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
112{
113 return 0;
114}
115
116static inline int hpet_set_rtc_irq_bit(unsigned long mask)
117{
118 return 0;
119}
120
121static inline int
122hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
123{
124 return 0;
125}
126
127static inline int hpet_set_periodic_freq(unsigned long freq)
128{
129 return 0;
130}
131
132static inline int hpet_rtc_dropped_irq(void)
133{
134 return 0;
135}
136
137static inline int hpet_rtc_timer_init(void)
138{
139 return 0;
140}
141
142extern irq_handler_t hpet_rtc_interrupt;
143
144static inline int hpet_register_irq_handler(irq_handler_t handler)
145{
146 return 0;
147}
148
149static inline int hpet_unregister_irq_handler(irq_handler_t handler)
150{
151 return 0;
152}
153
154#endif
155
156/*----------------------------------------------------------------*/
157
158#ifdef RTC_PORT
159
160/* Most newer x86 systems have two register banks, the first used
161 * for RTC and NVRAM and the second only for NVRAM. Caller must
162 * own rtc_lock ... and we won't worry about access during NMI.
163 */
164#define can_bank2 true
165
166static inline unsigned char cmos_read_bank2(unsigned char addr)
167{
168 outb(addr, RTC_PORT(2));
169 return inb(RTC_PORT(3));
170}
171
172static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
173{
174 outb(addr, RTC_PORT(2));
175 outb(val, RTC_PORT(3));
176}
177
178#else
179
180#define can_bank2 false
181
182static inline unsigned char cmos_read_bank2(unsigned char addr)
183{
184 return 0;
185}
186
187static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
188{
189}
190
191#endif
192
193/*----------------------------------------------------------------*/
194
195static int cmos_read_time(struct device *dev, struct rtc_time *t)
196{
197 /*
198 * If pm_trace abused the RTC for storage, set the timespec to 0,
199 * which tells the caller that this RTC value is unusable.
200 */
201 if (!pm_trace_rtc_valid())
202 return -EIO;
203
204 /* REVISIT: if the clock has a "century" register, use
205 * that instead of the heuristic in mc146818_get_time().
206 * That'll make Y3K compatility (year > 2070) easy!
207 */
208 mc146818_get_time(t);
209 return 0;
210}
211
212static int cmos_set_time(struct device *dev, struct rtc_time *t)
213{
214 /* REVISIT: set the "century" register if available
215 *
216 * NOTE: this ignores the issue whereby updating the seconds
217 * takes effect exactly 500ms after we write the register.
218 * (Also queueing and other delays before we get this far.)
219 */
220 return mc146818_set_time(t);
221}
222
223static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
224{
225 struct cmos_rtc *cmos = dev_get_drvdata(dev);
226 unsigned char rtc_control;
227
228 if (!is_valid_irq(cmos->irq))
229 return -EIO;
230
231 /* Basic alarms only support hour, minute, and seconds fields.
232 * Some also support day and month, for alarms up to a year in
233 * the future.
234 */
235
236 spin_lock_irq(&rtc_lock);
237 t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
238 t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
239 t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
240
241 if (cmos->day_alrm) {
242 /* ignore upper bits on readback per ACPI spec */
243 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
244 if (!t->time.tm_mday)
245 t->time.tm_mday = -1;
246
247 if (cmos->mon_alrm) {
248 t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
249 if (!t->time.tm_mon)
250 t->time.tm_mon = -1;
251 }
252 }
253
254 rtc_control = CMOS_READ(RTC_CONTROL);
255 spin_unlock_irq(&rtc_lock);
256
257 if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
258 if (((unsigned)t->time.tm_sec) < 0x60)
259 t->time.tm_sec = bcd2bin(t->time.tm_sec);
260 else
261 t->time.tm_sec = -1;
262 if (((unsigned)t->time.tm_min) < 0x60)
263 t->time.tm_min = bcd2bin(t->time.tm_min);
264 else
265 t->time.tm_min = -1;
266 if (((unsigned)t->time.tm_hour) < 0x24)
267 t->time.tm_hour = bcd2bin(t->time.tm_hour);
268 else
269 t->time.tm_hour = -1;
270
271 if (cmos->day_alrm) {
272 if (((unsigned)t->time.tm_mday) <= 0x31)
273 t->time.tm_mday = bcd2bin(t->time.tm_mday);
274 else
275 t->time.tm_mday = -1;
276
277 if (cmos->mon_alrm) {
278 if (((unsigned)t->time.tm_mon) <= 0x12)
279 t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
280 else
281 t->time.tm_mon = -1;
282 }
283 }
284 }
285
286 t->enabled = !!(rtc_control & RTC_AIE);
287 t->pending = 0;
288
289 return 0;
290}
291
292static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
293{
294 unsigned char rtc_intr;
295
296 /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
297 * allegedly some older rtcs need that to handle irqs properly
298 */
299 rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
300
301 if (is_hpet_enabled())
302 return;
303
304 rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
305 if (is_intr(rtc_intr))
306 rtc_update_irq(cmos->rtc, 1, rtc_intr);
307}
308
309static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
310{
311 unsigned char rtc_control;
312
313 /* flush any pending IRQ status, notably for update irqs,
314 * before we enable new IRQs
315 */
316 rtc_control = CMOS_READ(RTC_CONTROL);
317 cmos_checkintr(cmos, rtc_control);
318
319 rtc_control |= mask;
320 CMOS_WRITE(rtc_control, RTC_CONTROL);
321 hpet_set_rtc_irq_bit(mask);
322
323 cmos_checkintr(cmos, rtc_control);
324}
325
326static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
327{
328 unsigned char rtc_control;
329
330 rtc_control = CMOS_READ(RTC_CONTROL);
331 rtc_control &= ~mask;
332 CMOS_WRITE(rtc_control, RTC_CONTROL);
333 hpet_mask_rtc_irq_bit(mask);
334
335 cmos_checkintr(cmos, rtc_control);
336}
337
338static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t)
339{
340 struct cmos_rtc *cmos = dev_get_drvdata(dev);
341 struct rtc_time now;
342
343 cmos_read_time(dev, &now);
344
345 if (!cmos->day_alrm) {
346 time64_t t_max_date;
347 time64_t t_alrm;
348
349 t_max_date = rtc_tm_to_time64(&now);
350 t_max_date += 24 * 60 * 60 - 1;
351 t_alrm = rtc_tm_to_time64(&t->time);
352 if (t_alrm > t_max_date) {
353 dev_err(dev,
354 "Alarms can be up to one day in the future\n");
355 return -EINVAL;
356 }
357 } else if (!cmos->mon_alrm) {
358 struct rtc_time max_date = now;
359 time64_t t_max_date;
360 time64_t t_alrm;
361 int max_mday;
362
363 if (max_date.tm_mon == 11) {
364 max_date.tm_mon = 0;
365 max_date.tm_year += 1;
366 } else {
367 max_date.tm_mon += 1;
368 }
369 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
370 if (max_date.tm_mday > max_mday)
371 max_date.tm_mday = max_mday;
372
373 t_max_date = rtc_tm_to_time64(&max_date);
374 t_max_date -= 1;
375 t_alrm = rtc_tm_to_time64(&t->time);
376 if (t_alrm > t_max_date) {
377 dev_err(dev,
378 "Alarms can be up to one month in the future\n");
379 return -EINVAL;
380 }
381 } else {
382 struct rtc_time max_date = now;
383 time64_t t_max_date;
384 time64_t t_alrm;
385 int max_mday;
386
387 max_date.tm_year += 1;
388 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
389 if (max_date.tm_mday > max_mday)
390 max_date.tm_mday = max_mday;
391
392 t_max_date = rtc_tm_to_time64(&max_date);
393 t_max_date -= 1;
394 t_alrm = rtc_tm_to_time64(&t->time);
395 if (t_alrm > t_max_date) {
396 dev_err(dev,
397 "Alarms can be up to one year in the future\n");
398 return -EINVAL;
399 }
400 }
401
402 return 0;
403}
404
405static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
406{
407 struct cmos_rtc *cmos = dev_get_drvdata(dev);
408 unsigned char mon, mday, hrs, min, sec, rtc_control;
409 int ret;
410
411 if (!is_valid_irq(cmos->irq))
412 return -EIO;
413
414 ret = cmos_validate_alarm(dev, t);
415 if (ret < 0)
416 return ret;
417
418 mon = t->time.tm_mon + 1;
419 mday = t->time.tm_mday;
420 hrs = t->time.tm_hour;
421 min = t->time.tm_min;
422 sec = t->time.tm_sec;
423
424 rtc_control = CMOS_READ(RTC_CONTROL);
425 if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
426 /* Writing 0xff means "don't care" or "match all". */
427 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
428 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
429 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
430 min = (min < 60) ? bin2bcd(min) : 0xff;
431 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
432 }
433
434 spin_lock_irq(&rtc_lock);
435
436 /* next rtc irq must not be from previous alarm setting */
437 cmos_irq_disable(cmos, RTC_AIE);
438
439 /* update alarm */
440 CMOS_WRITE(hrs, RTC_HOURS_ALARM);
441 CMOS_WRITE(min, RTC_MINUTES_ALARM);
442 CMOS_WRITE(sec, RTC_SECONDS_ALARM);
443
444 /* the system may support an "enhanced" alarm */
445 if (cmos->day_alrm) {
446 CMOS_WRITE(mday, cmos->day_alrm);
447 if (cmos->mon_alrm)
448 CMOS_WRITE(mon, cmos->mon_alrm);
449 }
450
451 /* FIXME the HPET alarm glue currently ignores day_alrm
452 * and mon_alrm ...
453 */
454 hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
455
456 if (t->enabled)
457 cmos_irq_enable(cmos, RTC_AIE);
458
459 spin_unlock_irq(&rtc_lock);
460
461 cmos->alarm_expires = rtc_tm_to_time64(&t->time);
462
463 return 0;
464}
465
466static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
467{
468 struct cmos_rtc *cmos = dev_get_drvdata(dev);
469 unsigned long flags;
470
471 if (!is_valid_irq(cmos->irq))
472 return -EINVAL;
473
474 spin_lock_irqsave(&rtc_lock, flags);
475
476 if (enabled)
477 cmos_irq_enable(cmos, RTC_AIE);
478 else
479 cmos_irq_disable(cmos, RTC_AIE);
480
481 spin_unlock_irqrestore(&rtc_lock, flags);
482 return 0;
483}
484
485#if IS_ENABLED(CONFIG_RTC_INTF_PROC)
486
487static int cmos_procfs(struct device *dev, struct seq_file *seq)
488{
489 struct cmos_rtc *cmos = dev_get_drvdata(dev);
490 unsigned char rtc_control, valid;
491
492 spin_lock_irq(&rtc_lock);
493 rtc_control = CMOS_READ(RTC_CONTROL);
494 valid = CMOS_READ(RTC_VALID);
495 spin_unlock_irq(&rtc_lock);
496
497 /* NOTE: at least ICH6 reports battery status using a different
498 * (non-RTC) bit; and SQWE is ignored on many current systems.
499 */
500 seq_printf(seq,
501 "periodic_IRQ\t: %s\n"
502 "update_IRQ\t: %s\n"
503 "HPET_emulated\t: %s\n"
504 // "square_wave\t: %s\n"
505 "BCD\t\t: %s\n"
506 "DST_enable\t: %s\n"
507 "periodic_freq\t: %d\n"
508 "batt_status\t: %s\n",
509 (rtc_control & RTC_PIE) ? "yes" : "no",
510 (rtc_control & RTC_UIE) ? "yes" : "no",
511 is_hpet_enabled() ? "yes" : "no",
512 // (rtc_control & RTC_SQWE) ? "yes" : "no",
513 (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
514 (rtc_control & RTC_DST_EN) ? "yes" : "no",
515 cmos->rtc->irq_freq,
516 (valid & RTC_VRT) ? "okay" : "dead");
517
518 return 0;
519}
520
521#else
522#define cmos_procfs NULL
523#endif
524
525static const struct rtc_class_ops cmos_rtc_ops = {
526 .read_time = cmos_read_time,
527 .set_time = cmos_set_time,
528 .read_alarm = cmos_read_alarm,
529 .set_alarm = cmos_set_alarm,
530 .proc = cmos_procfs,
531 .alarm_irq_enable = cmos_alarm_irq_enable,
532};
533
534/*----------------------------------------------------------------*/
535
536/*
537 * All these chips have at least 64 bytes of address space, shared by
538 * RTC registers and NVRAM. Most of those bytes of NVRAM are used
539 * by boot firmware. Modern chips have 128 or 256 bytes.
540 */
541
542#define NVRAM_OFFSET (RTC_REG_D + 1)
543
544static int cmos_nvram_read(void *priv, unsigned int off, void *val,
545 size_t count)
546{
547 unsigned char *buf = val;
548 int retval;
549
550 off += NVRAM_OFFSET;
551 spin_lock_irq(&rtc_lock);
552 for (retval = 0; count; count--, off++, retval++) {
553 if (off < 128)
554 *buf++ = CMOS_READ(off);
555 else if (can_bank2)
556 *buf++ = cmos_read_bank2(off);
557 else
558 break;
559 }
560 spin_unlock_irq(&rtc_lock);
561
562 return retval;
563}
564
565static int cmos_nvram_write(void *priv, unsigned int off, void *val,
566 size_t count)
567{
568 struct cmos_rtc *cmos = priv;
569 unsigned char *buf = val;
570 int retval;
571
572 /* NOTE: on at least PCs and Ataris, the boot firmware uses a
573 * checksum on part of the NVRAM data. That's currently ignored
574 * here. If userspace is smart enough to know what fields of
575 * NVRAM to update, updating checksums is also part of its job.
576 */
577 off += NVRAM_OFFSET;
578 spin_lock_irq(&rtc_lock);
579 for (retval = 0; count; count--, off++, retval++) {
580 /* don't trash RTC registers */
581 if (off == cmos->day_alrm
582 || off == cmos->mon_alrm
583 || off == cmos->century)
584 buf++;
585 else if (off < 128)
586 CMOS_WRITE(*buf++, off);
587 else if (can_bank2)
588 cmos_write_bank2(*buf++, off);
589 else
590 break;
591 }
592 spin_unlock_irq(&rtc_lock);
593
594 return retval;
595}
596
597/*----------------------------------------------------------------*/
598
599static struct cmos_rtc cmos_rtc;
600
601static irqreturn_t cmos_interrupt(int irq, void *p)
602{
603 u8 irqstat;
604 u8 rtc_control;
605
606 spin_lock(&rtc_lock);
607
608 /* When the HPET interrupt handler calls us, the interrupt
609 * status is passed as arg1 instead of the irq number. But
610 * always clear irq status, even when HPET is in the way.
611 *
612 * Note that HPET and RTC are almost certainly out of phase,
613 * giving different IRQ status ...
614 */
615 irqstat = CMOS_READ(RTC_INTR_FLAGS);
616 rtc_control = CMOS_READ(RTC_CONTROL);
617 if (is_hpet_enabled())
618 irqstat = (unsigned long)irq & 0xF0;
619
620 /* If we were suspended, RTC_CONTROL may not be accurate since the
621 * bios may have cleared it.
622 */
623 if (!cmos_rtc.suspend_ctrl)
624 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
625 else
626 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
627
628 /* All Linux RTC alarms should be treated as if they were oneshot.
629 * Similar code may be needed in system wakeup paths, in case the
630 * alarm woke the system.
631 */
632 if (irqstat & RTC_AIE) {
633 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
634 rtc_control &= ~RTC_AIE;
635 CMOS_WRITE(rtc_control, RTC_CONTROL);
636 hpet_mask_rtc_irq_bit(RTC_AIE);
637 CMOS_READ(RTC_INTR_FLAGS);
638 }
639 spin_unlock(&rtc_lock);
640
641 if (is_intr(irqstat)) {
642 rtc_update_irq(p, 1, irqstat);
643 return IRQ_HANDLED;
644 } else
645 return IRQ_NONE;
646}
647
648#ifdef CONFIG_PNP
649#define INITSECTION
650
651#else
652#define INITSECTION __init
653#endif
654
655static int INITSECTION
656cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
657{
658 struct cmos_rtc_board_info *info = dev_get_platdata(dev);
659 int retval = 0;
660 unsigned char rtc_control;
661 unsigned address_space;
662 u32 flags = 0;
663 struct nvmem_config nvmem_cfg = {
664 .name = "cmos_nvram",
665 .word_size = 1,
666 .stride = 1,
667 .reg_read = cmos_nvram_read,
668 .reg_write = cmos_nvram_write,
669 .priv = &cmos_rtc,
670 };
671
672 /* there can be only one ... */
673 if (cmos_rtc.dev)
674 return -EBUSY;
675
676 if (!ports)
677 return -ENODEV;
678
679 /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
680 *
681 * REVISIT non-x86 systems may instead use memory space resources
682 * (needing ioremap etc), not i/o space resources like this ...
683 */
684 if (RTC_IOMAPPED)
685 ports = request_region(ports->start, resource_size(ports),
686 driver_name);
687 else
688 ports = request_mem_region(ports->start, resource_size(ports),
689 driver_name);
690 if (!ports) {
691 dev_dbg(dev, "i/o registers already in use\n");
692 return -EBUSY;
693 }
694
695 cmos_rtc.irq = rtc_irq;
696 cmos_rtc.iomem = ports;
697
698 /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
699 * driver did, but don't reject unknown configs. Old hardware
700 * won't address 128 bytes. Newer chips have multiple banks,
701 * though they may not be listed in one I/O resource.
702 */
703#if defined(CONFIG_ATARI)
704 address_space = 64;
705#elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
706 || defined(__sparc__) || defined(__mips__) \
707 || defined(__powerpc__)
708 address_space = 128;
709#else
710#warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
711 address_space = 128;
712#endif
713 if (can_bank2 && ports->end > (ports->start + 1))
714 address_space = 256;
715
716 /* For ACPI systems extension info comes from the FADT. On others,
717 * board specific setup provides it as appropriate. Systems where
718 * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
719 * some almost-clones) can provide hooks to make that behave.
720 *
721 * Note that ACPI doesn't preclude putting these registers into
722 * "extended" areas of the chip, including some that we won't yet
723 * expect CMOS_READ and friends to handle.
724 */
725 if (info) {
726 if (info->flags)
727 flags = info->flags;
728 if (info->address_space)
729 address_space = info->address_space;
730
731 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
732 cmos_rtc.day_alrm = info->rtc_day_alarm;
733 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
734 cmos_rtc.mon_alrm = info->rtc_mon_alarm;
735 if (info->rtc_century && info->rtc_century < 128)
736 cmos_rtc.century = info->rtc_century;
737
738 if (info->wake_on && info->wake_off) {
739 cmos_rtc.wake_on = info->wake_on;
740 cmos_rtc.wake_off = info->wake_off;
741 }
742 }
743
744 cmos_rtc.dev = dev;
745 dev_set_drvdata(dev, &cmos_rtc);
746
747 cmos_rtc.rtc = devm_rtc_allocate_device(dev);
748 if (IS_ERR(cmos_rtc.rtc)) {
749 retval = PTR_ERR(cmos_rtc.rtc);
750 goto cleanup0;
751 }
752
753 rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
754
755 spin_lock_irq(&rtc_lock);
756
757 if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
758 /* force periodic irq to CMOS reset default of 1024Hz;
759 *
760 * REVISIT it's been reported that at least one x86_64 ALI
761 * mobo doesn't use 32KHz here ... for portability we might
762 * need to do something about other clock frequencies.
763 */
764 cmos_rtc.rtc->irq_freq = 1024;
765 hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
766 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
767 }
768
769 /* disable irqs */
770 if (is_valid_irq(rtc_irq))
771 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
772
773 rtc_control = CMOS_READ(RTC_CONTROL);
774
775 spin_unlock_irq(&rtc_lock);
776
777 if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
778 dev_warn(dev, "only 24-hr supported\n");
779 retval = -ENXIO;
780 goto cleanup1;
781 }
782
783 hpet_rtc_timer_init();
784
785 if (is_valid_irq(rtc_irq)) {
786 irq_handler_t rtc_cmos_int_handler;
787
788 if (is_hpet_enabled()) {
789 rtc_cmos_int_handler = hpet_rtc_interrupt;
790 retval = hpet_register_irq_handler(cmos_interrupt);
791 if (retval) {
792 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
793 dev_warn(dev, "hpet_register_irq_handler "
794 " failed in rtc_init().");
795 goto cleanup1;
796 }
797 } else
798 rtc_cmos_int_handler = cmos_interrupt;
799
800 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
801 IRQF_SHARED, dev_name(&cmos_rtc.rtc->dev),
802 cmos_rtc.rtc);
803 if (retval < 0) {
804 dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
805 goto cleanup1;
806 }
807 }
808
809 cmos_rtc.rtc->ops = &cmos_rtc_ops;
810 cmos_rtc.rtc->nvram_old_abi = true;
811 retval = rtc_register_device(cmos_rtc.rtc);
812 if (retval)
813 goto cleanup2;
814
815 /* export at least the first block of NVRAM */
816 nvmem_cfg.size = address_space - NVRAM_OFFSET;
817 if (rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg))
818 dev_err(dev, "nvmem registration failed\n");
819
820 dev_info(dev, "%s%s, %d bytes nvram%s\n",
821 !is_valid_irq(rtc_irq) ? "no alarms" :
822 cmos_rtc.mon_alrm ? "alarms up to one year" :
823 cmos_rtc.day_alrm ? "alarms up to one month" :
824 "alarms up to one day",
825 cmos_rtc.century ? ", y3k" : "",
826 nvmem_cfg.size,
827 is_hpet_enabled() ? ", hpet irqs" : "");
828
829 return 0;
830
831cleanup2:
832 if (is_valid_irq(rtc_irq))
833 free_irq(rtc_irq, cmos_rtc.rtc);
834cleanup1:
835 cmos_rtc.dev = NULL;
836cleanup0:
837 if (RTC_IOMAPPED)
838 release_region(ports->start, resource_size(ports));
839 else
840 release_mem_region(ports->start, resource_size(ports));
841 return retval;
842}
843
844static void cmos_do_shutdown(int rtc_irq)
845{
846 spin_lock_irq(&rtc_lock);
847 if (is_valid_irq(rtc_irq))
848 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
849 spin_unlock_irq(&rtc_lock);
850}
851
852static void cmos_do_remove(struct device *dev)
853{
854 struct cmos_rtc *cmos = dev_get_drvdata(dev);
855 struct resource *ports;
856
857 cmos_do_shutdown(cmos->irq);
858
859 if (is_valid_irq(cmos->irq)) {
860 free_irq(cmos->irq, cmos->rtc);
861 hpet_unregister_irq_handler(cmos_interrupt);
862 }
863
864 cmos->rtc = NULL;
865
866 ports = cmos->iomem;
867 if (RTC_IOMAPPED)
868 release_region(ports->start, resource_size(ports));
869 else
870 release_mem_region(ports->start, resource_size(ports));
871 cmos->iomem = NULL;
872
873 cmos->dev = NULL;
874}
875
876static int cmos_aie_poweroff(struct device *dev)
877{
878 struct cmos_rtc *cmos = dev_get_drvdata(dev);
879 struct rtc_time now;
880 time64_t t_now;
881 int retval = 0;
882 unsigned char rtc_control;
883
884 if (!cmos->alarm_expires)
885 return -EINVAL;
886
887 spin_lock_irq(&rtc_lock);
888 rtc_control = CMOS_READ(RTC_CONTROL);
889 spin_unlock_irq(&rtc_lock);
890
891 /* We only care about the situation where AIE is disabled. */
892 if (rtc_control & RTC_AIE)
893 return -EBUSY;
894
895 cmos_read_time(dev, &now);
896 t_now = rtc_tm_to_time64(&now);
897
898 /*
899 * When enabling "RTC wake-up" in BIOS setup, the machine reboots
900 * automatically right after shutdown on some buggy boxes.
901 * This automatic rebooting issue won't happen when the alarm
902 * time is larger than now+1 seconds.
903 *
904 * If the alarm time is equal to now+1 seconds, the issue can be
905 * prevented by cancelling the alarm.
906 */
907 if (cmos->alarm_expires == t_now + 1) {
908 struct rtc_wkalrm alarm;
909
910 /* Cancel the AIE timer by configuring the past time. */
911 rtc_time64_to_tm(t_now - 1, &alarm.time);
912 alarm.enabled = 0;
913 retval = cmos_set_alarm(dev, &alarm);
914 } else if (cmos->alarm_expires > t_now + 1) {
915 retval = -EBUSY;
916 }
917
918 return retval;
919}
920
921static int cmos_suspend(struct device *dev)
922{
923 struct cmos_rtc *cmos = dev_get_drvdata(dev);
924 unsigned char tmp;
925
926 /* only the alarm might be a wakeup event source */
927 spin_lock_irq(&rtc_lock);
928 cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
929 if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
930 unsigned char mask;
931
932 if (device_may_wakeup(dev))
933 mask = RTC_IRQMASK & ~RTC_AIE;
934 else
935 mask = RTC_IRQMASK;
936 tmp &= ~mask;
937 CMOS_WRITE(tmp, RTC_CONTROL);
938 hpet_mask_rtc_irq_bit(mask);
939
940 cmos_checkintr(cmos, tmp);
941 }
942 spin_unlock_irq(&rtc_lock);
943
944 if (tmp & RTC_AIE) {
945 cmos->enabled_wake = 1;
946 if (cmos->wake_on)
947 cmos->wake_on(dev);
948 else
949 enable_irq_wake(cmos->irq);
950 }
951
952 cmos_read_alarm(dev, &cmos->saved_wkalrm);
953
954 dev_dbg(dev, "suspend%s, ctrl %02x\n",
955 (tmp & RTC_AIE) ? ", alarm may wake" : "",
956 tmp);
957
958 return 0;
959}
960
961/* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
962 * after a detour through G3 "mechanical off", although the ACPI spec
963 * says wakeup should only work from G1/S4 "hibernate". To most users,
964 * distinctions between S4 and S5 are pointless. So when the hardware
965 * allows, don't draw that distinction.
966 */
967static inline int cmos_poweroff(struct device *dev)
968{
969 if (!IS_ENABLED(CONFIG_PM))
970 return -ENOSYS;
971
972 return cmos_suspend(dev);
973}
974
975static void cmos_check_wkalrm(struct device *dev)
976{
977 struct cmos_rtc *cmos = dev_get_drvdata(dev);
978 struct rtc_wkalrm current_alarm;
979 time64_t t_current_expires;
980 time64_t t_saved_expires;
981
982 cmos_read_alarm(dev, ¤t_alarm);
983 t_current_expires = rtc_tm_to_time64(¤t_alarm.time);
984 t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
985 if (t_current_expires != t_saved_expires ||
986 cmos->saved_wkalrm.enabled != current_alarm.enabled) {
987 cmos_set_alarm(dev, &cmos->saved_wkalrm);
988 }
989}
990
991static void cmos_check_acpi_rtc_status(struct device *dev,
992 unsigned char *rtc_control);
993
994static int __maybe_unused cmos_resume(struct device *dev)
995{
996 struct cmos_rtc *cmos = dev_get_drvdata(dev);
997 unsigned char tmp;
998
999 if (cmos->enabled_wake) {
1000 if (cmos->wake_off)
1001 cmos->wake_off(dev);
1002 else
1003 disable_irq_wake(cmos->irq);
1004 cmos->enabled_wake = 0;
1005 }
1006
1007 /* The BIOS might have changed the alarm, restore it */
1008 cmos_check_wkalrm(dev);
1009
1010 spin_lock_irq(&rtc_lock);
1011 tmp = cmos->suspend_ctrl;
1012 cmos->suspend_ctrl = 0;
1013 /* re-enable any irqs previously active */
1014 if (tmp & RTC_IRQMASK) {
1015 unsigned char mask;
1016
1017 if (device_may_wakeup(dev))
1018 hpet_rtc_timer_init();
1019
1020 do {
1021 CMOS_WRITE(tmp, RTC_CONTROL);
1022 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1023
1024 mask = CMOS_READ(RTC_INTR_FLAGS);
1025 mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1026 if (!is_hpet_enabled() || !is_intr(mask))
1027 break;
1028
1029 /* force one-shot behavior if HPET blocked
1030 * the wake alarm's irq
1031 */
1032 rtc_update_irq(cmos->rtc, 1, mask);
1033 tmp &= ~RTC_AIE;
1034 hpet_mask_rtc_irq_bit(RTC_AIE);
1035 } while (mask & RTC_AIE);
1036
1037 if (tmp & RTC_AIE)
1038 cmos_check_acpi_rtc_status(dev, &tmp);
1039 }
1040 spin_unlock_irq(&rtc_lock);
1041
1042 dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1043
1044 return 0;
1045}
1046
1047static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1048
1049/*----------------------------------------------------------------*/
1050
1051/* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1052 * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1053 * probably list them in similar PNPBIOS tables; so PNP is more common.
1054 *
1055 * We don't use legacy "poke at the hardware" probing. Ancient PCs that
1056 * predate even PNPBIOS should set up platform_bus devices.
1057 */
1058
1059#ifdef CONFIG_ACPI
1060
1061#include <linux/acpi.h>
1062
1063static u32 rtc_handler(void *context)
1064{
1065 struct device *dev = context;
1066 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1067 unsigned char rtc_control = 0;
1068 unsigned char rtc_intr;
1069 unsigned long flags;
1070
1071 spin_lock_irqsave(&rtc_lock, flags);
1072 if (cmos_rtc.suspend_ctrl)
1073 rtc_control = CMOS_READ(RTC_CONTROL);
1074 if (rtc_control & RTC_AIE) {
1075 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1076 CMOS_WRITE(rtc_control, RTC_CONTROL);
1077 rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1078 rtc_update_irq(cmos->rtc, 1, rtc_intr);
1079 }
1080 spin_unlock_irqrestore(&rtc_lock, flags);
1081
1082 pm_wakeup_hard_event(dev);
1083 acpi_clear_event(ACPI_EVENT_RTC);
1084 acpi_disable_event(ACPI_EVENT_RTC, 0);
1085 return ACPI_INTERRUPT_HANDLED;
1086}
1087
1088static inline void rtc_wake_setup(struct device *dev)
1089{
1090 acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1091 /*
1092 * After the RTC handler is installed, the Fixed_RTC event should
1093 * be disabled. Only when the RTC alarm is set will it be enabled.
1094 */
1095 acpi_clear_event(ACPI_EVENT_RTC);
1096 acpi_disable_event(ACPI_EVENT_RTC, 0);
1097}
1098
1099static void rtc_wake_on(struct device *dev)
1100{
1101 acpi_clear_event(ACPI_EVENT_RTC);
1102 acpi_enable_event(ACPI_EVENT_RTC, 0);
1103}
1104
1105static void rtc_wake_off(struct device *dev)
1106{
1107 acpi_disable_event(ACPI_EVENT_RTC, 0);
1108}
1109
1110/* Every ACPI platform has a mc146818 compatible "cmos rtc". Here we find
1111 * its device node and pass extra config data. This helps its driver use
1112 * capabilities that the now-obsolete mc146818 didn't have, and informs it
1113 * that this board's RTC is wakeup-capable (per ACPI spec).
1114 */
1115static struct cmos_rtc_board_info acpi_rtc_info;
1116
1117static void cmos_wake_setup(struct device *dev)
1118{
1119 if (acpi_disabled)
1120 return;
1121
1122 rtc_wake_setup(dev);
1123 acpi_rtc_info.wake_on = rtc_wake_on;
1124 acpi_rtc_info.wake_off = rtc_wake_off;
1125
1126 /* workaround bug in some ACPI tables */
1127 if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1128 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1129 acpi_gbl_FADT.month_alarm);
1130 acpi_gbl_FADT.month_alarm = 0;
1131 }
1132
1133 acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1134 acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1135 acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1136
1137 /* NOTE: S4_RTC_WAKE is NOT currently useful to Linux */
1138 if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1139 dev_info(dev, "RTC can wake from S4\n");
1140
1141 dev->platform_data = &acpi_rtc_info;
1142
1143 /* RTC always wakes from S1/S2/S3, and often S4/STD */
1144 device_init_wakeup(dev, 1);
1145}
1146
1147static void cmos_check_acpi_rtc_status(struct device *dev,
1148 unsigned char *rtc_control)
1149{
1150 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1151 acpi_event_status rtc_status;
1152 acpi_status status;
1153
1154 if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1155 return;
1156
1157 status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1158 if (ACPI_FAILURE(status)) {
1159 dev_err(dev, "Could not get RTC status\n");
1160 } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1161 unsigned char mask;
1162 *rtc_control &= ~RTC_AIE;
1163 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1164 mask = CMOS_READ(RTC_INTR_FLAGS);
1165 rtc_update_irq(cmos->rtc, 1, mask);
1166 }
1167}
1168
1169#else
1170
1171static void cmos_wake_setup(struct device *dev)
1172{
1173}
1174
1175static void cmos_check_acpi_rtc_status(struct device *dev,
1176 unsigned char *rtc_control)
1177{
1178}
1179
1180#endif
1181
1182#ifdef CONFIG_PNP
1183
1184#include <linux/pnp.h>
1185
1186static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1187{
1188 cmos_wake_setup(&pnp->dev);
1189
1190 if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1191 unsigned int irq = 0;
1192#ifdef CONFIG_X86
1193 /* Some machines contain a PNP entry for the RTC, but
1194 * don't define the IRQ. It should always be safe to
1195 * hardcode it on systems with a legacy PIC.
1196 */
1197 if (nr_legacy_irqs())
1198 irq = 8;
1199#endif
1200 return cmos_do_probe(&pnp->dev,
1201 pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1202 } else {
1203 return cmos_do_probe(&pnp->dev,
1204 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1205 pnp_irq(pnp, 0));
1206 }
1207}
1208
1209static void cmos_pnp_remove(struct pnp_dev *pnp)
1210{
1211 cmos_do_remove(&pnp->dev);
1212}
1213
1214static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1215{
1216 struct device *dev = &pnp->dev;
1217 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1218
1219 if (system_state == SYSTEM_POWER_OFF) {
1220 int retval = cmos_poweroff(dev);
1221
1222 if (cmos_aie_poweroff(dev) < 0 && !retval)
1223 return;
1224 }
1225
1226 cmos_do_shutdown(cmos->irq);
1227}
1228
1229static const struct pnp_device_id rtc_ids[] = {
1230 { .id = "PNP0b00", },
1231 { .id = "PNP0b01", },
1232 { .id = "PNP0b02", },
1233 { },
1234};
1235MODULE_DEVICE_TABLE(pnp, rtc_ids);
1236
1237static struct pnp_driver cmos_pnp_driver = {
1238 .name = (char *) driver_name,
1239 .id_table = rtc_ids,
1240 .probe = cmos_pnp_probe,
1241 .remove = cmos_pnp_remove,
1242 .shutdown = cmos_pnp_shutdown,
1243
1244 /* flag ensures resume() gets called, and stops syslog spam */
1245 .flags = PNP_DRIVER_RES_DO_NOT_CHANGE,
1246 .driver = {
1247 .pm = &cmos_pm_ops,
1248 },
1249};
1250
1251#endif /* CONFIG_PNP */
1252
1253#ifdef CONFIG_OF
1254static const struct of_device_id of_cmos_match[] = {
1255 {
1256 .compatible = "motorola,mc146818",
1257 },
1258 { },
1259};
1260MODULE_DEVICE_TABLE(of, of_cmos_match);
1261
1262static __init void cmos_of_init(struct platform_device *pdev)
1263{
1264 struct device_node *node = pdev->dev.of_node;
1265 const __be32 *val;
1266
1267 if (!node)
1268 return;
1269
1270 val = of_get_property(node, "ctrl-reg", NULL);
1271 if (val)
1272 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1273
1274 val = of_get_property(node, "freq-reg", NULL);
1275 if (val)
1276 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1277}
1278#else
1279static inline void cmos_of_init(struct platform_device *pdev) {}
1280#endif
1281/*----------------------------------------------------------------*/
1282
1283/* Platform setup should have set up an RTC device, when PNP is
1284 * unavailable ... this could happen even on (older) PCs.
1285 */
1286
1287static int __init cmos_platform_probe(struct platform_device *pdev)
1288{
1289 struct resource *resource;
1290 int irq;
1291
1292 cmos_of_init(pdev);
1293 cmos_wake_setup(&pdev->dev);
1294
1295 if (RTC_IOMAPPED)
1296 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1297 else
1298 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1299 irq = platform_get_irq(pdev, 0);
1300 if (irq < 0)
1301 irq = -1;
1302
1303 return cmos_do_probe(&pdev->dev, resource, irq);
1304}
1305
1306static int cmos_platform_remove(struct platform_device *pdev)
1307{
1308 cmos_do_remove(&pdev->dev);
1309 return 0;
1310}
1311
1312static void cmos_platform_shutdown(struct platform_device *pdev)
1313{
1314 struct device *dev = &pdev->dev;
1315 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1316
1317 if (system_state == SYSTEM_POWER_OFF) {
1318 int retval = cmos_poweroff(dev);
1319
1320 if (cmos_aie_poweroff(dev) < 0 && !retval)
1321 return;
1322 }
1323
1324 cmos_do_shutdown(cmos->irq);
1325}
1326
1327/* work with hotplug and coldplug */
1328MODULE_ALIAS("platform:rtc_cmos");
1329
1330static struct platform_driver cmos_platform_driver = {
1331 .remove = cmos_platform_remove,
1332 .shutdown = cmos_platform_shutdown,
1333 .driver = {
1334 .name = driver_name,
1335 .pm = &cmos_pm_ops,
1336 .of_match_table = of_match_ptr(of_cmos_match),
1337 }
1338};
1339
1340#ifdef CONFIG_PNP
1341static bool pnp_driver_registered;
1342#endif
1343static bool platform_driver_registered;
1344
1345static int __init cmos_init(void)
1346{
1347 int retval = 0;
1348
1349#ifdef CONFIG_PNP
1350 retval = pnp_register_driver(&cmos_pnp_driver);
1351 if (retval == 0)
1352 pnp_driver_registered = true;
1353#endif
1354
1355 if (!cmos_rtc.dev) {
1356 retval = platform_driver_probe(&cmos_platform_driver,
1357 cmos_platform_probe);
1358 if (retval == 0)
1359 platform_driver_registered = true;
1360 }
1361
1362 if (retval == 0)
1363 return 0;
1364
1365#ifdef CONFIG_PNP
1366 if (pnp_driver_registered)
1367 pnp_unregister_driver(&cmos_pnp_driver);
1368#endif
1369 return retval;
1370}
1371module_init(cmos_init);
1372
1373static void __exit cmos_exit(void)
1374{
1375#ifdef CONFIG_PNP
1376 if (pnp_driver_registered)
1377 pnp_unregister_driver(&cmos_pnp_driver);
1378#endif
1379 if (platform_driver_registered)
1380 platform_driver_unregister(&cmos_platform_driver);
1381}
1382module_exit(cmos_exit);
1383
1384
1385MODULE_AUTHOR("David Brownell");
1386MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1387MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * RTC class driver for "CMOS RTC": PCs, ACPI, etc
4 *
5 * Copyright (C) 1996 Paul Gortmaker (drivers/char/rtc.c)
6 * Copyright (C) 2006 David Brownell (convert to new framework)
7 */
8
9/*
10 * The original "cmos clock" chip was an MC146818 chip, now obsolete.
11 * That defined the register interface now provided by all PCs, some
12 * non-PC systems, and incorporated into ACPI. Modern PC chipsets
13 * integrate an MC146818 clone in their southbridge, and boards use
14 * that instead of discrete clones like the DS12887 or M48T86. There
15 * are also clones that connect using the LPC bus.
16 *
17 * That register API is also used directly by various other drivers
18 * (notably for integrated NVRAM), infrastructure (x86 has code to
19 * bypass the RTC framework, directly reading the RTC during boot
20 * and updating minutes/seconds for systems using NTP synch) and
21 * utilities (like userspace 'hwclock', if no /dev node exists).
22 *
23 * So **ALL** calls to CMOS_READ and CMOS_WRITE must be done with
24 * interrupts disabled, holding the global rtc_lock, to exclude those
25 * other drivers and utilities on correctly configured systems.
26 */
27
28#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
29
30#include <linux/kernel.h>
31#include <linux/module.h>
32#include <linux/init.h>
33#include <linux/interrupt.h>
34#include <linux/spinlock.h>
35#include <linux/platform_device.h>
36#include <linux/log2.h>
37#include <linux/pm.h>
38#include <linux/of.h>
39#include <linux/of_platform.h>
40#ifdef CONFIG_X86
41#include <asm/i8259.h>
42#include <asm/processor.h>
43#include <linux/dmi.h>
44#endif
45
46/* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
47#include <linux/mc146818rtc.h>
48
49#ifdef CONFIG_ACPI
50/*
51 * Use ACPI SCI to replace HPET interrupt for RTC Alarm event
52 *
53 * If cleared, ACPI SCI is only used to wake up the system from suspend
54 *
55 * If set, ACPI SCI is used to handle UIE/AIE and system wakeup
56 */
57
58static bool use_acpi_alarm;
59module_param(use_acpi_alarm, bool, 0444);
60
61static inline int cmos_use_acpi_alarm(void)
62{
63 return use_acpi_alarm;
64}
65#else /* !CONFIG_ACPI */
66
67static inline int cmos_use_acpi_alarm(void)
68{
69 return 0;
70}
71#endif
72
73struct cmos_rtc {
74 struct rtc_device *rtc;
75 struct device *dev;
76 int irq;
77 struct resource *iomem;
78 time64_t alarm_expires;
79
80 void (*wake_on)(struct device *);
81 void (*wake_off)(struct device *);
82
83 u8 enabled_wake;
84 u8 suspend_ctrl;
85
86 /* newer hardware extends the original register set */
87 u8 day_alrm;
88 u8 mon_alrm;
89 u8 century;
90
91 struct rtc_wkalrm saved_wkalrm;
92};
93
94/* both platform and pnp busses use negative numbers for invalid irqs */
95#define is_valid_irq(n) ((n) > 0)
96
97static const char driver_name[] = "rtc_cmos";
98
99/* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
100 * always mask it against the irq enable bits in RTC_CONTROL. Bit values
101 * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
102 */
103#define RTC_IRQMASK (RTC_PF | RTC_AF | RTC_UF)
104
105static inline int is_intr(u8 rtc_intr)
106{
107 if (!(rtc_intr & RTC_IRQF))
108 return 0;
109 return rtc_intr & RTC_IRQMASK;
110}
111
112/*----------------------------------------------------------------*/
113
114/* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
115 * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
116 * used in a broken "legacy replacement" mode. The breakage includes
117 * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
118 * other (better) use.
119 *
120 * When that broken mode is in use, platform glue provides a partial
121 * emulation of hardware RTC IRQ facilities using HPET #1. We don't
122 * want to use HPET for anything except those IRQs though...
123 */
124#ifdef CONFIG_HPET_EMULATE_RTC
125#include <asm/hpet.h>
126#else
127
128static inline int is_hpet_enabled(void)
129{
130 return 0;
131}
132
133static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
134{
135 return 0;
136}
137
138static inline int hpet_set_rtc_irq_bit(unsigned long mask)
139{
140 return 0;
141}
142
143static inline int
144hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
145{
146 return 0;
147}
148
149static inline int hpet_set_periodic_freq(unsigned long freq)
150{
151 return 0;
152}
153
154static inline int hpet_rtc_dropped_irq(void)
155{
156 return 0;
157}
158
159static inline int hpet_rtc_timer_init(void)
160{
161 return 0;
162}
163
164extern irq_handler_t hpet_rtc_interrupt;
165
166static inline int hpet_register_irq_handler(irq_handler_t handler)
167{
168 return 0;
169}
170
171static inline int hpet_unregister_irq_handler(irq_handler_t handler)
172{
173 return 0;
174}
175
176#endif
177
178/* Don't use HPET for RTC Alarm event if ACPI Fixed event is used */
179static inline int use_hpet_alarm(void)
180{
181 return is_hpet_enabled() && !cmos_use_acpi_alarm();
182}
183
184/*----------------------------------------------------------------*/
185
186#ifdef RTC_PORT
187
188/* Most newer x86 systems have two register banks, the first used
189 * for RTC and NVRAM and the second only for NVRAM. Caller must
190 * own rtc_lock ... and we won't worry about access during NMI.
191 */
192#define can_bank2 true
193
194static inline unsigned char cmos_read_bank2(unsigned char addr)
195{
196 outb(addr, RTC_PORT(2));
197 return inb(RTC_PORT(3));
198}
199
200static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
201{
202 outb(addr, RTC_PORT(2));
203 outb(val, RTC_PORT(3));
204}
205
206#else
207
208#define can_bank2 false
209
210static inline unsigned char cmos_read_bank2(unsigned char addr)
211{
212 return 0;
213}
214
215static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
216{
217}
218
219#endif
220
221/*----------------------------------------------------------------*/
222
223static int cmos_read_time(struct device *dev, struct rtc_time *t)
224{
225 /*
226 * If pm_trace abused the RTC for storage, set the timespec to 0,
227 * which tells the caller that this RTC value is unusable.
228 */
229 if (!pm_trace_rtc_valid())
230 return -EIO;
231
232 /* REVISIT: if the clock has a "century" register, use
233 * that instead of the heuristic in mc146818_get_time().
234 * That'll make Y3K compatility (year > 2070) easy!
235 */
236 mc146818_get_time(t);
237 return 0;
238}
239
240static int cmos_set_time(struct device *dev, struct rtc_time *t)
241{
242 /* REVISIT: set the "century" register if available
243 *
244 * NOTE: this ignores the issue whereby updating the seconds
245 * takes effect exactly 500ms after we write the register.
246 * (Also queueing and other delays before we get this far.)
247 */
248 return mc146818_set_time(t);
249}
250
251static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
252{
253 struct cmos_rtc *cmos = dev_get_drvdata(dev);
254 unsigned char rtc_control;
255
256 /* This not only a rtc_op, but also called directly */
257 if (!is_valid_irq(cmos->irq))
258 return -EIO;
259
260 /* Basic alarms only support hour, minute, and seconds fields.
261 * Some also support day and month, for alarms up to a year in
262 * the future.
263 */
264
265 spin_lock_irq(&rtc_lock);
266 t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
267 t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
268 t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
269
270 if (cmos->day_alrm) {
271 /* ignore upper bits on readback per ACPI spec */
272 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
273 if (!t->time.tm_mday)
274 t->time.tm_mday = -1;
275
276 if (cmos->mon_alrm) {
277 t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
278 if (!t->time.tm_mon)
279 t->time.tm_mon = -1;
280 }
281 }
282
283 rtc_control = CMOS_READ(RTC_CONTROL);
284 spin_unlock_irq(&rtc_lock);
285
286 if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
287 if (((unsigned)t->time.tm_sec) < 0x60)
288 t->time.tm_sec = bcd2bin(t->time.tm_sec);
289 else
290 t->time.tm_sec = -1;
291 if (((unsigned)t->time.tm_min) < 0x60)
292 t->time.tm_min = bcd2bin(t->time.tm_min);
293 else
294 t->time.tm_min = -1;
295 if (((unsigned)t->time.tm_hour) < 0x24)
296 t->time.tm_hour = bcd2bin(t->time.tm_hour);
297 else
298 t->time.tm_hour = -1;
299
300 if (cmos->day_alrm) {
301 if (((unsigned)t->time.tm_mday) <= 0x31)
302 t->time.tm_mday = bcd2bin(t->time.tm_mday);
303 else
304 t->time.tm_mday = -1;
305
306 if (cmos->mon_alrm) {
307 if (((unsigned)t->time.tm_mon) <= 0x12)
308 t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
309 else
310 t->time.tm_mon = -1;
311 }
312 }
313 }
314
315 t->enabled = !!(rtc_control & RTC_AIE);
316 t->pending = 0;
317
318 return 0;
319}
320
321static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
322{
323 unsigned char rtc_intr;
324
325 /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
326 * allegedly some older rtcs need that to handle irqs properly
327 */
328 rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
329
330 if (use_hpet_alarm())
331 return;
332
333 rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
334 if (is_intr(rtc_intr))
335 rtc_update_irq(cmos->rtc, 1, rtc_intr);
336}
337
338static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
339{
340 unsigned char rtc_control;
341
342 /* flush any pending IRQ status, notably for update irqs,
343 * before we enable new IRQs
344 */
345 rtc_control = CMOS_READ(RTC_CONTROL);
346 cmos_checkintr(cmos, rtc_control);
347
348 rtc_control |= mask;
349 CMOS_WRITE(rtc_control, RTC_CONTROL);
350 if (use_hpet_alarm())
351 hpet_set_rtc_irq_bit(mask);
352
353 if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
354 if (cmos->wake_on)
355 cmos->wake_on(cmos->dev);
356 }
357
358 cmos_checkintr(cmos, rtc_control);
359}
360
361static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
362{
363 unsigned char rtc_control;
364
365 rtc_control = CMOS_READ(RTC_CONTROL);
366 rtc_control &= ~mask;
367 CMOS_WRITE(rtc_control, RTC_CONTROL);
368 if (use_hpet_alarm())
369 hpet_mask_rtc_irq_bit(mask);
370
371 if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
372 if (cmos->wake_off)
373 cmos->wake_off(cmos->dev);
374 }
375
376 cmos_checkintr(cmos, rtc_control);
377}
378
379static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t)
380{
381 struct cmos_rtc *cmos = dev_get_drvdata(dev);
382 struct rtc_time now;
383
384 cmos_read_time(dev, &now);
385
386 if (!cmos->day_alrm) {
387 time64_t t_max_date;
388 time64_t t_alrm;
389
390 t_max_date = rtc_tm_to_time64(&now);
391 t_max_date += 24 * 60 * 60 - 1;
392 t_alrm = rtc_tm_to_time64(&t->time);
393 if (t_alrm > t_max_date) {
394 dev_err(dev,
395 "Alarms can be up to one day in the future\n");
396 return -EINVAL;
397 }
398 } else if (!cmos->mon_alrm) {
399 struct rtc_time max_date = now;
400 time64_t t_max_date;
401 time64_t t_alrm;
402 int max_mday;
403
404 if (max_date.tm_mon == 11) {
405 max_date.tm_mon = 0;
406 max_date.tm_year += 1;
407 } else {
408 max_date.tm_mon += 1;
409 }
410 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
411 if (max_date.tm_mday > max_mday)
412 max_date.tm_mday = max_mday;
413
414 t_max_date = rtc_tm_to_time64(&max_date);
415 t_max_date -= 1;
416 t_alrm = rtc_tm_to_time64(&t->time);
417 if (t_alrm > t_max_date) {
418 dev_err(dev,
419 "Alarms can be up to one month in the future\n");
420 return -EINVAL;
421 }
422 } else {
423 struct rtc_time max_date = now;
424 time64_t t_max_date;
425 time64_t t_alrm;
426 int max_mday;
427
428 max_date.tm_year += 1;
429 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
430 if (max_date.tm_mday > max_mday)
431 max_date.tm_mday = max_mday;
432
433 t_max_date = rtc_tm_to_time64(&max_date);
434 t_max_date -= 1;
435 t_alrm = rtc_tm_to_time64(&t->time);
436 if (t_alrm > t_max_date) {
437 dev_err(dev,
438 "Alarms can be up to one year in the future\n");
439 return -EINVAL;
440 }
441 }
442
443 return 0;
444}
445
446static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
447{
448 struct cmos_rtc *cmos = dev_get_drvdata(dev);
449 unsigned char mon, mday, hrs, min, sec, rtc_control;
450 int ret;
451
452 /* This not only a rtc_op, but also called directly */
453 if (!is_valid_irq(cmos->irq))
454 return -EIO;
455
456 ret = cmos_validate_alarm(dev, t);
457 if (ret < 0)
458 return ret;
459
460 mon = t->time.tm_mon + 1;
461 mday = t->time.tm_mday;
462 hrs = t->time.tm_hour;
463 min = t->time.tm_min;
464 sec = t->time.tm_sec;
465
466 rtc_control = CMOS_READ(RTC_CONTROL);
467 if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
468 /* Writing 0xff means "don't care" or "match all". */
469 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
470 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
471 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
472 min = (min < 60) ? bin2bcd(min) : 0xff;
473 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
474 }
475
476 spin_lock_irq(&rtc_lock);
477
478 /* next rtc irq must not be from previous alarm setting */
479 cmos_irq_disable(cmos, RTC_AIE);
480
481 /* update alarm */
482 CMOS_WRITE(hrs, RTC_HOURS_ALARM);
483 CMOS_WRITE(min, RTC_MINUTES_ALARM);
484 CMOS_WRITE(sec, RTC_SECONDS_ALARM);
485
486 /* the system may support an "enhanced" alarm */
487 if (cmos->day_alrm) {
488 CMOS_WRITE(mday, cmos->day_alrm);
489 if (cmos->mon_alrm)
490 CMOS_WRITE(mon, cmos->mon_alrm);
491 }
492
493 if (use_hpet_alarm()) {
494 /*
495 * FIXME the HPET alarm glue currently ignores day_alrm
496 * and mon_alrm ...
497 */
498 hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min,
499 t->time.tm_sec);
500 }
501
502 if (t->enabled)
503 cmos_irq_enable(cmos, RTC_AIE);
504
505 spin_unlock_irq(&rtc_lock);
506
507 cmos->alarm_expires = rtc_tm_to_time64(&t->time);
508
509 return 0;
510}
511
512static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
513{
514 struct cmos_rtc *cmos = dev_get_drvdata(dev);
515 unsigned long flags;
516
517 spin_lock_irqsave(&rtc_lock, flags);
518
519 if (enabled)
520 cmos_irq_enable(cmos, RTC_AIE);
521 else
522 cmos_irq_disable(cmos, RTC_AIE);
523
524 spin_unlock_irqrestore(&rtc_lock, flags);
525 return 0;
526}
527
528#if IS_ENABLED(CONFIG_RTC_INTF_PROC)
529
530static int cmos_procfs(struct device *dev, struct seq_file *seq)
531{
532 struct cmos_rtc *cmos = dev_get_drvdata(dev);
533 unsigned char rtc_control, valid;
534
535 spin_lock_irq(&rtc_lock);
536 rtc_control = CMOS_READ(RTC_CONTROL);
537 valid = CMOS_READ(RTC_VALID);
538 spin_unlock_irq(&rtc_lock);
539
540 /* NOTE: at least ICH6 reports battery status using a different
541 * (non-RTC) bit; and SQWE is ignored on many current systems.
542 */
543 seq_printf(seq,
544 "periodic_IRQ\t: %s\n"
545 "update_IRQ\t: %s\n"
546 "HPET_emulated\t: %s\n"
547 // "square_wave\t: %s\n"
548 "BCD\t\t: %s\n"
549 "DST_enable\t: %s\n"
550 "periodic_freq\t: %d\n"
551 "batt_status\t: %s\n",
552 (rtc_control & RTC_PIE) ? "yes" : "no",
553 (rtc_control & RTC_UIE) ? "yes" : "no",
554 use_hpet_alarm() ? "yes" : "no",
555 // (rtc_control & RTC_SQWE) ? "yes" : "no",
556 (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
557 (rtc_control & RTC_DST_EN) ? "yes" : "no",
558 cmos->rtc->irq_freq,
559 (valid & RTC_VRT) ? "okay" : "dead");
560
561 return 0;
562}
563
564#else
565#define cmos_procfs NULL
566#endif
567
568static const struct rtc_class_ops cmos_rtc_ops = {
569 .read_time = cmos_read_time,
570 .set_time = cmos_set_time,
571 .read_alarm = cmos_read_alarm,
572 .set_alarm = cmos_set_alarm,
573 .proc = cmos_procfs,
574 .alarm_irq_enable = cmos_alarm_irq_enable,
575};
576
577/*----------------------------------------------------------------*/
578
579/*
580 * All these chips have at least 64 bytes of address space, shared by
581 * RTC registers and NVRAM. Most of those bytes of NVRAM are used
582 * by boot firmware. Modern chips have 128 or 256 bytes.
583 */
584
585#define NVRAM_OFFSET (RTC_REG_D + 1)
586
587static int cmos_nvram_read(void *priv, unsigned int off, void *val,
588 size_t count)
589{
590 unsigned char *buf = val;
591 int retval;
592
593 off += NVRAM_OFFSET;
594 spin_lock_irq(&rtc_lock);
595 for (retval = 0; count; count--, off++, retval++) {
596 if (off < 128)
597 *buf++ = CMOS_READ(off);
598 else if (can_bank2)
599 *buf++ = cmos_read_bank2(off);
600 else
601 break;
602 }
603 spin_unlock_irq(&rtc_lock);
604
605 return retval;
606}
607
608static int cmos_nvram_write(void *priv, unsigned int off, void *val,
609 size_t count)
610{
611 struct cmos_rtc *cmos = priv;
612 unsigned char *buf = val;
613 int retval;
614
615 /* NOTE: on at least PCs and Ataris, the boot firmware uses a
616 * checksum on part of the NVRAM data. That's currently ignored
617 * here. If userspace is smart enough to know what fields of
618 * NVRAM to update, updating checksums is also part of its job.
619 */
620 off += NVRAM_OFFSET;
621 spin_lock_irq(&rtc_lock);
622 for (retval = 0; count; count--, off++, retval++) {
623 /* don't trash RTC registers */
624 if (off == cmos->day_alrm
625 || off == cmos->mon_alrm
626 || off == cmos->century)
627 buf++;
628 else if (off < 128)
629 CMOS_WRITE(*buf++, off);
630 else if (can_bank2)
631 cmos_write_bank2(*buf++, off);
632 else
633 break;
634 }
635 spin_unlock_irq(&rtc_lock);
636
637 return retval;
638}
639
640/*----------------------------------------------------------------*/
641
642static struct cmos_rtc cmos_rtc;
643
644static irqreturn_t cmos_interrupt(int irq, void *p)
645{
646 u8 irqstat;
647 u8 rtc_control;
648
649 spin_lock(&rtc_lock);
650
651 /* When the HPET interrupt handler calls us, the interrupt
652 * status is passed as arg1 instead of the irq number. But
653 * always clear irq status, even when HPET is in the way.
654 *
655 * Note that HPET and RTC are almost certainly out of phase,
656 * giving different IRQ status ...
657 */
658 irqstat = CMOS_READ(RTC_INTR_FLAGS);
659 rtc_control = CMOS_READ(RTC_CONTROL);
660 if (use_hpet_alarm())
661 irqstat = (unsigned long)irq & 0xF0;
662
663 /* If we were suspended, RTC_CONTROL may not be accurate since the
664 * bios may have cleared it.
665 */
666 if (!cmos_rtc.suspend_ctrl)
667 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
668 else
669 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
670
671 /* All Linux RTC alarms should be treated as if they were oneshot.
672 * Similar code may be needed in system wakeup paths, in case the
673 * alarm woke the system.
674 */
675 if (irqstat & RTC_AIE) {
676 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
677 rtc_control &= ~RTC_AIE;
678 CMOS_WRITE(rtc_control, RTC_CONTROL);
679 if (use_hpet_alarm())
680 hpet_mask_rtc_irq_bit(RTC_AIE);
681 CMOS_READ(RTC_INTR_FLAGS);
682 }
683 spin_unlock(&rtc_lock);
684
685 if (is_intr(irqstat)) {
686 rtc_update_irq(p, 1, irqstat);
687 return IRQ_HANDLED;
688 } else
689 return IRQ_NONE;
690}
691
692#ifdef CONFIG_PNP
693#define INITSECTION
694
695#else
696#define INITSECTION __init
697#endif
698
699static int INITSECTION
700cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
701{
702 struct cmos_rtc_board_info *info = dev_get_platdata(dev);
703 int retval = 0;
704 unsigned char rtc_control;
705 unsigned address_space;
706 u32 flags = 0;
707 struct nvmem_config nvmem_cfg = {
708 .name = "cmos_nvram",
709 .word_size = 1,
710 .stride = 1,
711 .reg_read = cmos_nvram_read,
712 .reg_write = cmos_nvram_write,
713 .priv = &cmos_rtc,
714 };
715
716 /* there can be only one ... */
717 if (cmos_rtc.dev)
718 return -EBUSY;
719
720 if (!ports)
721 return -ENODEV;
722
723 /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
724 *
725 * REVISIT non-x86 systems may instead use memory space resources
726 * (needing ioremap etc), not i/o space resources like this ...
727 */
728 if (RTC_IOMAPPED)
729 ports = request_region(ports->start, resource_size(ports),
730 driver_name);
731 else
732 ports = request_mem_region(ports->start, resource_size(ports),
733 driver_name);
734 if (!ports) {
735 dev_dbg(dev, "i/o registers already in use\n");
736 return -EBUSY;
737 }
738
739 cmos_rtc.irq = rtc_irq;
740 cmos_rtc.iomem = ports;
741
742 /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
743 * driver did, but don't reject unknown configs. Old hardware
744 * won't address 128 bytes. Newer chips have multiple banks,
745 * though they may not be listed in one I/O resource.
746 */
747#if defined(CONFIG_ATARI)
748 address_space = 64;
749#elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
750 || defined(__sparc__) || defined(__mips__) \
751 || defined(__powerpc__)
752 address_space = 128;
753#else
754#warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
755 address_space = 128;
756#endif
757 if (can_bank2 && ports->end > (ports->start + 1))
758 address_space = 256;
759
760 /* For ACPI systems extension info comes from the FADT. On others,
761 * board specific setup provides it as appropriate. Systems where
762 * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
763 * some almost-clones) can provide hooks to make that behave.
764 *
765 * Note that ACPI doesn't preclude putting these registers into
766 * "extended" areas of the chip, including some that we won't yet
767 * expect CMOS_READ and friends to handle.
768 */
769 if (info) {
770 if (info->flags)
771 flags = info->flags;
772 if (info->address_space)
773 address_space = info->address_space;
774
775 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
776 cmos_rtc.day_alrm = info->rtc_day_alarm;
777 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
778 cmos_rtc.mon_alrm = info->rtc_mon_alarm;
779 if (info->rtc_century && info->rtc_century < 128)
780 cmos_rtc.century = info->rtc_century;
781
782 if (info->wake_on && info->wake_off) {
783 cmos_rtc.wake_on = info->wake_on;
784 cmos_rtc.wake_off = info->wake_off;
785 }
786 }
787
788 cmos_rtc.dev = dev;
789 dev_set_drvdata(dev, &cmos_rtc);
790
791 cmos_rtc.rtc = devm_rtc_allocate_device(dev);
792 if (IS_ERR(cmos_rtc.rtc)) {
793 retval = PTR_ERR(cmos_rtc.rtc);
794 goto cleanup0;
795 }
796
797 rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
798
799 spin_lock_irq(&rtc_lock);
800
801 /* Ensure that the RTC is accessible. Bit 6 must be 0! */
802 if ((CMOS_READ(RTC_VALID) & 0x40) != 0) {
803 spin_unlock_irq(&rtc_lock);
804 dev_warn(dev, "not accessible\n");
805 retval = -ENXIO;
806 goto cleanup1;
807 }
808
809 if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
810 /* force periodic irq to CMOS reset default of 1024Hz;
811 *
812 * REVISIT it's been reported that at least one x86_64 ALI
813 * mobo doesn't use 32KHz here ... for portability we might
814 * need to do something about other clock frequencies.
815 */
816 cmos_rtc.rtc->irq_freq = 1024;
817 if (use_hpet_alarm())
818 hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
819 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
820 }
821
822 /* disable irqs */
823 if (is_valid_irq(rtc_irq))
824 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
825
826 rtc_control = CMOS_READ(RTC_CONTROL);
827
828 spin_unlock_irq(&rtc_lock);
829
830 if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
831 dev_warn(dev, "only 24-hr supported\n");
832 retval = -ENXIO;
833 goto cleanup1;
834 }
835
836 if (use_hpet_alarm())
837 hpet_rtc_timer_init();
838
839 if (is_valid_irq(rtc_irq)) {
840 irq_handler_t rtc_cmos_int_handler;
841
842 if (use_hpet_alarm()) {
843 rtc_cmos_int_handler = hpet_rtc_interrupt;
844 retval = hpet_register_irq_handler(cmos_interrupt);
845 if (retval) {
846 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
847 dev_warn(dev, "hpet_register_irq_handler "
848 " failed in rtc_init().");
849 goto cleanup1;
850 }
851 } else
852 rtc_cmos_int_handler = cmos_interrupt;
853
854 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
855 0, dev_name(&cmos_rtc.rtc->dev),
856 cmos_rtc.rtc);
857 if (retval < 0) {
858 dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
859 goto cleanup1;
860 }
861 } else {
862 clear_bit(RTC_FEATURE_ALARM, cmos_rtc.rtc->features);
863 }
864
865 cmos_rtc.rtc->ops = &cmos_rtc_ops;
866
867 retval = devm_rtc_register_device(cmos_rtc.rtc);
868 if (retval)
869 goto cleanup2;
870
871 /* Set the sync offset for the periodic 11min update correct */
872 cmos_rtc.rtc->set_offset_nsec = NSEC_PER_SEC / 2;
873
874 /* export at least the first block of NVRAM */
875 nvmem_cfg.size = address_space - NVRAM_OFFSET;
876 devm_rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg);
877
878 dev_info(dev, "%s%s, %d bytes nvram%s\n",
879 !is_valid_irq(rtc_irq) ? "no alarms" :
880 cmos_rtc.mon_alrm ? "alarms up to one year" :
881 cmos_rtc.day_alrm ? "alarms up to one month" :
882 "alarms up to one day",
883 cmos_rtc.century ? ", y3k" : "",
884 nvmem_cfg.size,
885 use_hpet_alarm() ? ", hpet irqs" : "");
886
887 return 0;
888
889cleanup2:
890 if (is_valid_irq(rtc_irq))
891 free_irq(rtc_irq, cmos_rtc.rtc);
892cleanup1:
893 cmos_rtc.dev = NULL;
894cleanup0:
895 if (RTC_IOMAPPED)
896 release_region(ports->start, resource_size(ports));
897 else
898 release_mem_region(ports->start, resource_size(ports));
899 return retval;
900}
901
902static void cmos_do_shutdown(int rtc_irq)
903{
904 spin_lock_irq(&rtc_lock);
905 if (is_valid_irq(rtc_irq))
906 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
907 spin_unlock_irq(&rtc_lock);
908}
909
910static void cmos_do_remove(struct device *dev)
911{
912 struct cmos_rtc *cmos = dev_get_drvdata(dev);
913 struct resource *ports;
914
915 cmos_do_shutdown(cmos->irq);
916
917 if (is_valid_irq(cmos->irq)) {
918 free_irq(cmos->irq, cmos->rtc);
919 if (use_hpet_alarm())
920 hpet_unregister_irq_handler(cmos_interrupt);
921 }
922
923 cmos->rtc = NULL;
924
925 ports = cmos->iomem;
926 if (RTC_IOMAPPED)
927 release_region(ports->start, resource_size(ports));
928 else
929 release_mem_region(ports->start, resource_size(ports));
930 cmos->iomem = NULL;
931
932 cmos->dev = NULL;
933}
934
935static int cmos_aie_poweroff(struct device *dev)
936{
937 struct cmos_rtc *cmos = dev_get_drvdata(dev);
938 struct rtc_time now;
939 time64_t t_now;
940 int retval = 0;
941 unsigned char rtc_control;
942
943 if (!cmos->alarm_expires)
944 return -EINVAL;
945
946 spin_lock_irq(&rtc_lock);
947 rtc_control = CMOS_READ(RTC_CONTROL);
948 spin_unlock_irq(&rtc_lock);
949
950 /* We only care about the situation where AIE is disabled. */
951 if (rtc_control & RTC_AIE)
952 return -EBUSY;
953
954 cmos_read_time(dev, &now);
955 t_now = rtc_tm_to_time64(&now);
956
957 /*
958 * When enabling "RTC wake-up" in BIOS setup, the machine reboots
959 * automatically right after shutdown on some buggy boxes.
960 * This automatic rebooting issue won't happen when the alarm
961 * time is larger than now+1 seconds.
962 *
963 * If the alarm time is equal to now+1 seconds, the issue can be
964 * prevented by cancelling the alarm.
965 */
966 if (cmos->alarm_expires == t_now + 1) {
967 struct rtc_wkalrm alarm;
968
969 /* Cancel the AIE timer by configuring the past time. */
970 rtc_time64_to_tm(t_now - 1, &alarm.time);
971 alarm.enabled = 0;
972 retval = cmos_set_alarm(dev, &alarm);
973 } else if (cmos->alarm_expires > t_now + 1) {
974 retval = -EBUSY;
975 }
976
977 return retval;
978}
979
980static int cmos_suspend(struct device *dev)
981{
982 struct cmos_rtc *cmos = dev_get_drvdata(dev);
983 unsigned char tmp;
984
985 /* only the alarm might be a wakeup event source */
986 spin_lock_irq(&rtc_lock);
987 cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
988 if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
989 unsigned char mask;
990
991 if (device_may_wakeup(dev))
992 mask = RTC_IRQMASK & ~RTC_AIE;
993 else
994 mask = RTC_IRQMASK;
995 tmp &= ~mask;
996 CMOS_WRITE(tmp, RTC_CONTROL);
997 if (use_hpet_alarm())
998 hpet_mask_rtc_irq_bit(mask);
999 cmos_checkintr(cmos, tmp);
1000 }
1001 spin_unlock_irq(&rtc_lock);
1002
1003 if ((tmp & RTC_AIE) && !cmos_use_acpi_alarm()) {
1004 cmos->enabled_wake = 1;
1005 if (cmos->wake_on)
1006 cmos->wake_on(dev);
1007 else
1008 enable_irq_wake(cmos->irq);
1009 }
1010
1011 memset(&cmos->saved_wkalrm, 0, sizeof(struct rtc_wkalrm));
1012 cmos_read_alarm(dev, &cmos->saved_wkalrm);
1013
1014 dev_dbg(dev, "suspend%s, ctrl %02x\n",
1015 (tmp & RTC_AIE) ? ", alarm may wake" : "",
1016 tmp);
1017
1018 return 0;
1019}
1020
1021/* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
1022 * after a detour through G3 "mechanical off", although the ACPI spec
1023 * says wakeup should only work from G1/S4 "hibernate". To most users,
1024 * distinctions between S4 and S5 are pointless. So when the hardware
1025 * allows, don't draw that distinction.
1026 */
1027static inline int cmos_poweroff(struct device *dev)
1028{
1029 if (!IS_ENABLED(CONFIG_PM))
1030 return -ENOSYS;
1031
1032 return cmos_suspend(dev);
1033}
1034
1035static void cmos_check_wkalrm(struct device *dev)
1036{
1037 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1038 struct rtc_wkalrm current_alarm;
1039 time64_t t_now;
1040 time64_t t_current_expires;
1041 time64_t t_saved_expires;
1042 struct rtc_time now;
1043
1044 /* Check if we have RTC Alarm armed */
1045 if (!(cmos->suspend_ctrl & RTC_AIE))
1046 return;
1047
1048 cmos_read_time(dev, &now);
1049 t_now = rtc_tm_to_time64(&now);
1050
1051 /*
1052 * ACPI RTC wake event is cleared after resume from STR,
1053 * ACK the rtc irq here
1054 */
1055 if (t_now >= cmos->alarm_expires && cmos_use_acpi_alarm()) {
1056 local_irq_disable();
1057 cmos_interrupt(0, (void *)cmos->rtc);
1058 local_irq_enable();
1059 return;
1060 }
1061
1062 memset(¤t_alarm, 0, sizeof(struct rtc_wkalrm));
1063 cmos_read_alarm(dev, ¤t_alarm);
1064 t_current_expires = rtc_tm_to_time64(¤t_alarm.time);
1065 t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
1066 if (t_current_expires != t_saved_expires ||
1067 cmos->saved_wkalrm.enabled != current_alarm.enabled) {
1068 cmos_set_alarm(dev, &cmos->saved_wkalrm);
1069 }
1070}
1071
1072static void cmos_check_acpi_rtc_status(struct device *dev,
1073 unsigned char *rtc_control);
1074
1075static int __maybe_unused cmos_resume(struct device *dev)
1076{
1077 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1078 unsigned char tmp;
1079
1080 if (cmos->enabled_wake && !cmos_use_acpi_alarm()) {
1081 if (cmos->wake_off)
1082 cmos->wake_off(dev);
1083 else
1084 disable_irq_wake(cmos->irq);
1085 cmos->enabled_wake = 0;
1086 }
1087
1088 /* The BIOS might have changed the alarm, restore it */
1089 cmos_check_wkalrm(dev);
1090
1091 spin_lock_irq(&rtc_lock);
1092 tmp = cmos->suspend_ctrl;
1093 cmos->suspend_ctrl = 0;
1094 /* re-enable any irqs previously active */
1095 if (tmp & RTC_IRQMASK) {
1096 unsigned char mask;
1097
1098 if (device_may_wakeup(dev) && use_hpet_alarm())
1099 hpet_rtc_timer_init();
1100
1101 do {
1102 CMOS_WRITE(tmp, RTC_CONTROL);
1103 if (use_hpet_alarm())
1104 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1105
1106 mask = CMOS_READ(RTC_INTR_FLAGS);
1107 mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1108 if (!use_hpet_alarm() || !is_intr(mask))
1109 break;
1110
1111 /* force one-shot behavior if HPET blocked
1112 * the wake alarm's irq
1113 */
1114 rtc_update_irq(cmos->rtc, 1, mask);
1115 tmp &= ~RTC_AIE;
1116 hpet_mask_rtc_irq_bit(RTC_AIE);
1117 } while (mask & RTC_AIE);
1118
1119 if (tmp & RTC_AIE)
1120 cmos_check_acpi_rtc_status(dev, &tmp);
1121 }
1122 spin_unlock_irq(&rtc_lock);
1123
1124 dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1125
1126 return 0;
1127}
1128
1129static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1130
1131/*----------------------------------------------------------------*/
1132
1133/* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1134 * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1135 * probably list them in similar PNPBIOS tables; so PNP is more common.
1136 *
1137 * We don't use legacy "poke at the hardware" probing. Ancient PCs that
1138 * predate even PNPBIOS should set up platform_bus devices.
1139 */
1140
1141#ifdef CONFIG_ACPI
1142
1143#include <linux/acpi.h>
1144
1145static u32 rtc_handler(void *context)
1146{
1147 struct device *dev = context;
1148 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1149 unsigned char rtc_control = 0;
1150 unsigned char rtc_intr;
1151 unsigned long flags;
1152
1153
1154 /*
1155 * Always update rtc irq when ACPI is used as RTC Alarm.
1156 * Or else, ACPI SCI is enabled during suspend/resume only,
1157 * update rtc irq in that case.
1158 */
1159 if (cmos_use_acpi_alarm())
1160 cmos_interrupt(0, (void *)cmos->rtc);
1161 else {
1162 /* Fix me: can we use cmos_interrupt() here as well? */
1163 spin_lock_irqsave(&rtc_lock, flags);
1164 if (cmos_rtc.suspend_ctrl)
1165 rtc_control = CMOS_READ(RTC_CONTROL);
1166 if (rtc_control & RTC_AIE) {
1167 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1168 CMOS_WRITE(rtc_control, RTC_CONTROL);
1169 rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1170 rtc_update_irq(cmos->rtc, 1, rtc_intr);
1171 }
1172 spin_unlock_irqrestore(&rtc_lock, flags);
1173 }
1174
1175 pm_wakeup_hard_event(dev);
1176 acpi_clear_event(ACPI_EVENT_RTC);
1177 acpi_disable_event(ACPI_EVENT_RTC, 0);
1178 return ACPI_INTERRUPT_HANDLED;
1179}
1180
1181static inline void rtc_wake_setup(struct device *dev)
1182{
1183 acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1184 /*
1185 * After the RTC handler is installed, the Fixed_RTC event should
1186 * be disabled. Only when the RTC alarm is set will it be enabled.
1187 */
1188 acpi_clear_event(ACPI_EVENT_RTC);
1189 acpi_disable_event(ACPI_EVENT_RTC, 0);
1190}
1191
1192static void rtc_wake_on(struct device *dev)
1193{
1194 acpi_clear_event(ACPI_EVENT_RTC);
1195 acpi_enable_event(ACPI_EVENT_RTC, 0);
1196}
1197
1198static void rtc_wake_off(struct device *dev)
1199{
1200 acpi_disable_event(ACPI_EVENT_RTC, 0);
1201}
1202
1203#ifdef CONFIG_X86
1204/* Enable use_acpi_alarm mode for Intel platforms no earlier than 2015 */
1205static void use_acpi_alarm_quirks(void)
1206{
1207 if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
1208 return;
1209
1210 if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
1211 return;
1212
1213 if (!is_hpet_enabled())
1214 return;
1215
1216 if (dmi_get_bios_year() < 2015)
1217 return;
1218
1219 use_acpi_alarm = true;
1220}
1221#else
1222static inline void use_acpi_alarm_quirks(void) { }
1223#endif
1224
1225/* Every ACPI platform has a mc146818 compatible "cmos rtc". Here we find
1226 * its device node and pass extra config data. This helps its driver use
1227 * capabilities that the now-obsolete mc146818 didn't have, and informs it
1228 * that this board's RTC is wakeup-capable (per ACPI spec).
1229 */
1230static struct cmos_rtc_board_info acpi_rtc_info;
1231
1232static void cmos_wake_setup(struct device *dev)
1233{
1234 if (acpi_disabled)
1235 return;
1236
1237 use_acpi_alarm_quirks();
1238
1239 rtc_wake_setup(dev);
1240 acpi_rtc_info.wake_on = rtc_wake_on;
1241 acpi_rtc_info.wake_off = rtc_wake_off;
1242
1243 /* workaround bug in some ACPI tables */
1244 if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1245 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1246 acpi_gbl_FADT.month_alarm);
1247 acpi_gbl_FADT.month_alarm = 0;
1248 }
1249
1250 acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1251 acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1252 acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1253
1254 /* NOTE: S4_RTC_WAKE is NOT currently useful to Linux */
1255 if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1256 dev_info(dev, "RTC can wake from S4\n");
1257
1258 dev->platform_data = &acpi_rtc_info;
1259
1260 /* RTC always wakes from S1/S2/S3, and often S4/STD */
1261 device_init_wakeup(dev, 1);
1262}
1263
1264static void cmos_check_acpi_rtc_status(struct device *dev,
1265 unsigned char *rtc_control)
1266{
1267 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1268 acpi_event_status rtc_status;
1269 acpi_status status;
1270
1271 if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1272 return;
1273
1274 status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1275 if (ACPI_FAILURE(status)) {
1276 dev_err(dev, "Could not get RTC status\n");
1277 } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1278 unsigned char mask;
1279 *rtc_control &= ~RTC_AIE;
1280 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1281 mask = CMOS_READ(RTC_INTR_FLAGS);
1282 rtc_update_irq(cmos->rtc, 1, mask);
1283 }
1284}
1285
1286#else
1287
1288static void cmos_wake_setup(struct device *dev)
1289{
1290}
1291
1292static void cmos_check_acpi_rtc_status(struct device *dev,
1293 unsigned char *rtc_control)
1294{
1295}
1296
1297#endif
1298
1299#ifdef CONFIG_PNP
1300
1301#include <linux/pnp.h>
1302
1303static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1304{
1305 cmos_wake_setup(&pnp->dev);
1306
1307 if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1308 unsigned int irq = 0;
1309#ifdef CONFIG_X86
1310 /* Some machines contain a PNP entry for the RTC, but
1311 * don't define the IRQ. It should always be safe to
1312 * hardcode it on systems with a legacy PIC.
1313 */
1314 if (nr_legacy_irqs())
1315 irq = RTC_IRQ;
1316#endif
1317 return cmos_do_probe(&pnp->dev,
1318 pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1319 } else {
1320 return cmos_do_probe(&pnp->dev,
1321 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1322 pnp_irq(pnp, 0));
1323 }
1324}
1325
1326static void cmos_pnp_remove(struct pnp_dev *pnp)
1327{
1328 cmos_do_remove(&pnp->dev);
1329}
1330
1331static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1332{
1333 struct device *dev = &pnp->dev;
1334 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1335
1336 if (system_state == SYSTEM_POWER_OFF) {
1337 int retval = cmos_poweroff(dev);
1338
1339 if (cmos_aie_poweroff(dev) < 0 && !retval)
1340 return;
1341 }
1342
1343 cmos_do_shutdown(cmos->irq);
1344}
1345
1346static const struct pnp_device_id rtc_ids[] = {
1347 { .id = "PNP0b00", },
1348 { .id = "PNP0b01", },
1349 { .id = "PNP0b02", },
1350 { },
1351};
1352MODULE_DEVICE_TABLE(pnp, rtc_ids);
1353
1354static struct pnp_driver cmos_pnp_driver = {
1355 .name = driver_name,
1356 .id_table = rtc_ids,
1357 .probe = cmos_pnp_probe,
1358 .remove = cmos_pnp_remove,
1359 .shutdown = cmos_pnp_shutdown,
1360
1361 /* flag ensures resume() gets called, and stops syslog spam */
1362 .flags = PNP_DRIVER_RES_DO_NOT_CHANGE,
1363 .driver = {
1364 .pm = &cmos_pm_ops,
1365 },
1366};
1367
1368#endif /* CONFIG_PNP */
1369
1370#ifdef CONFIG_OF
1371static const struct of_device_id of_cmos_match[] = {
1372 {
1373 .compatible = "motorola,mc146818",
1374 },
1375 { },
1376};
1377MODULE_DEVICE_TABLE(of, of_cmos_match);
1378
1379static __init void cmos_of_init(struct platform_device *pdev)
1380{
1381 struct device_node *node = pdev->dev.of_node;
1382 const __be32 *val;
1383
1384 if (!node)
1385 return;
1386
1387 val = of_get_property(node, "ctrl-reg", NULL);
1388 if (val)
1389 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1390
1391 val = of_get_property(node, "freq-reg", NULL);
1392 if (val)
1393 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1394}
1395#else
1396static inline void cmos_of_init(struct platform_device *pdev) {}
1397#endif
1398/*----------------------------------------------------------------*/
1399
1400/* Platform setup should have set up an RTC device, when PNP is
1401 * unavailable ... this could happen even on (older) PCs.
1402 */
1403
1404static int __init cmos_platform_probe(struct platform_device *pdev)
1405{
1406 struct resource *resource;
1407 int irq;
1408
1409 cmos_of_init(pdev);
1410 cmos_wake_setup(&pdev->dev);
1411
1412 if (RTC_IOMAPPED)
1413 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1414 else
1415 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1416 irq = platform_get_irq(pdev, 0);
1417 if (irq < 0)
1418 irq = -1;
1419
1420 return cmos_do_probe(&pdev->dev, resource, irq);
1421}
1422
1423static int cmos_platform_remove(struct platform_device *pdev)
1424{
1425 cmos_do_remove(&pdev->dev);
1426 return 0;
1427}
1428
1429static void cmos_platform_shutdown(struct platform_device *pdev)
1430{
1431 struct device *dev = &pdev->dev;
1432 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1433
1434 if (system_state == SYSTEM_POWER_OFF) {
1435 int retval = cmos_poweroff(dev);
1436
1437 if (cmos_aie_poweroff(dev) < 0 && !retval)
1438 return;
1439 }
1440
1441 cmos_do_shutdown(cmos->irq);
1442}
1443
1444/* work with hotplug and coldplug */
1445MODULE_ALIAS("platform:rtc_cmos");
1446
1447static struct platform_driver cmos_platform_driver = {
1448 .remove = cmos_platform_remove,
1449 .shutdown = cmos_platform_shutdown,
1450 .driver = {
1451 .name = driver_name,
1452 .pm = &cmos_pm_ops,
1453 .of_match_table = of_match_ptr(of_cmos_match),
1454 }
1455};
1456
1457#ifdef CONFIG_PNP
1458static bool pnp_driver_registered;
1459#endif
1460static bool platform_driver_registered;
1461
1462static int __init cmos_init(void)
1463{
1464 int retval = 0;
1465
1466#ifdef CONFIG_PNP
1467 retval = pnp_register_driver(&cmos_pnp_driver);
1468 if (retval == 0)
1469 pnp_driver_registered = true;
1470#endif
1471
1472 if (!cmos_rtc.dev) {
1473 retval = platform_driver_probe(&cmos_platform_driver,
1474 cmos_platform_probe);
1475 if (retval == 0)
1476 platform_driver_registered = true;
1477 }
1478
1479 if (retval == 0)
1480 return 0;
1481
1482#ifdef CONFIG_PNP
1483 if (pnp_driver_registered)
1484 pnp_unregister_driver(&cmos_pnp_driver);
1485#endif
1486 return retval;
1487}
1488module_init(cmos_init);
1489
1490static void __exit cmos_exit(void)
1491{
1492#ifdef CONFIG_PNP
1493 if (pnp_driver_registered)
1494 pnp_unregister_driver(&cmos_pnp_driver);
1495#endif
1496 if (platform_driver_registered)
1497 platform_driver_unregister(&cmos_platform_driver);
1498}
1499module_exit(cmos_exit);
1500
1501
1502MODULE_AUTHOR("David Brownell");
1503MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1504MODULE_LICENSE("GPL");