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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
45/* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
46#include <asm-generic/rtc.h>
47
48struct cmos_rtc {
49 struct rtc_device *rtc;
50 struct device *dev;
51 int irq;
52 struct resource *iomem;
53 time64_t alarm_expires;
54
55 void (*wake_on)(struct device *);
56 void (*wake_off)(struct device *);
57
58 u8 enabled_wake;
59 u8 suspend_ctrl;
60
61 /* newer hardware extends the original register set */
62 u8 day_alrm;
63 u8 mon_alrm;
64 u8 century;
65};
66
67/* both platform and pnp busses use negative numbers for invalid irqs */
68#define is_valid_irq(n) ((n) > 0)
69
70static const char driver_name[] = "rtc_cmos";
71
72/* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
73 * always mask it against the irq enable bits in RTC_CONTROL. Bit values
74 * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
75 */
76#define RTC_IRQMASK (RTC_PF | RTC_AF | RTC_UF)
77
78static inline int is_intr(u8 rtc_intr)
79{
80 if (!(rtc_intr & RTC_IRQF))
81 return 0;
82 return rtc_intr & RTC_IRQMASK;
83}
84
85/*----------------------------------------------------------------*/
86
87/* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
88 * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
89 * used in a broken "legacy replacement" mode. The breakage includes
90 * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
91 * other (better) use.
92 *
93 * When that broken mode is in use, platform glue provides a partial
94 * emulation of hardware RTC IRQ facilities using HPET #1. We don't
95 * want to use HPET for anything except those IRQs though...
96 */
97#ifdef CONFIG_HPET_EMULATE_RTC
98#include <asm/hpet.h>
99#else
100
101static inline int is_hpet_enabled(void)
102{
103 return 0;
104}
105
106static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
107{
108 return 0;
109}
110
111static inline int hpet_set_rtc_irq_bit(unsigned long mask)
112{
113 return 0;
114}
115
116static inline int
117hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
118{
119 return 0;
120}
121
122static inline int hpet_set_periodic_freq(unsigned long freq)
123{
124 return 0;
125}
126
127static inline int hpet_rtc_dropped_irq(void)
128{
129 return 0;
130}
131
132static inline int hpet_rtc_timer_init(void)
133{
134 return 0;
135}
136
137extern irq_handler_t hpet_rtc_interrupt;
138
139static inline int hpet_register_irq_handler(irq_handler_t handler)
140{
141 return 0;
142}
143
144static inline int hpet_unregister_irq_handler(irq_handler_t handler)
145{
146 return 0;
147}
148
149#endif
150
151/*----------------------------------------------------------------*/
152
153#ifdef RTC_PORT
154
155/* Most newer x86 systems have two register banks, the first used
156 * for RTC and NVRAM and the second only for NVRAM. Caller must
157 * own rtc_lock ... and we won't worry about access during NMI.
158 */
159#define can_bank2 true
160
161static inline unsigned char cmos_read_bank2(unsigned char addr)
162{
163 outb(addr, RTC_PORT(2));
164 return inb(RTC_PORT(3));
165}
166
167static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
168{
169 outb(addr, RTC_PORT(2));
170 outb(val, RTC_PORT(3));
171}
172
173#else
174
175#define can_bank2 false
176
177static inline unsigned char cmos_read_bank2(unsigned char addr)
178{
179 return 0;
180}
181
182static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
183{
184}
185
186#endif
187
188/*----------------------------------------------------------------*/
189
190static int cmos_read_time(struct device *dev, struct rtc_time *t)
191{
192 /* REVISIT: if the clock has a "century" register, use
193 * that instead of the heuristic in get_rtc_time().
194 * That'll make Y3K compatility (year > 2070) easy!
195 */
196 get_rtc_time(t);
197 return 0;
198}
199
200static int cmos_set_time(struct device *dev, struct rtc_time *t)
201{
202 /* REVISIT: set the "century" register if available
203 *
204 * NOTE: this ignores the issue whereby updating the seconds
205 * takes effect exactly 500ms after we write the register.
206 * (Also queueing and other delays before we get this far.)
207 */
208 return set_rtc_time(t);
209}
210
211static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
212{
213 struct cmos_rtc *cmos = dev_get_drvdata(dev);
214 unsigned char rtc_control;
215
216 if (!is_valid_irq(cmos->irq))
217 return -EIO;
218
219 /* Basic alarms only support hour, minute, and seconds fields.
220 * Some also support day and month, for alarms up to a year in
221 * the future.
222 */
223 t->time.tm_mday = -1;
224 t->time.tm_mon = -1;
225
226 spin_lock_irq(&rtc_lock);
227 t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
228 t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
229 t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
230
231 if (cmos->day_alrm) {
232 /* ignore upper bits on readback per ACPI spec */
233 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
234 if (!t->time.tm_mday)
235 t->time.tm_mday = -1;
236
237 if (cmos->mon_alrm) {
238 t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
239 if (!t->time.tm_mon)
240 t->time.tm_mon = -1;
241 }
242 }
243
244 rtc_control = CMOS_READ(RTC_CONTROL);
245 spin_unlock_irq(&rtc_lock);
246
247 if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
248 if (((unsigned)t->time.tm_sec) < 0x60)
249 t->time.tm_sec = bcd2bin(t->time.tm_sec);
250 else
251 t->time.tm_sec = -1;
252 if (((unsigned)t->time.tm_min) < 0x60)
253 t->time.tm_min = bcd2bin(t->time.tm_min);
254 else
255 t->time.tm_min = -1;
256 if (((unsigned)t->time.tm_hour) < 0x24)
257 t->time.tm_hour = bcd2bin(t->time.tm_hour);
258 else
259 t->time.tm_hour = -1;
260
261 if (cmos->day_alrm) {
262 if (((unsigned)t->time.tm_mday) <= 0x31)
263 t->time.tm_mday = bcd2bin(t->time.tm_mday);
264 else
265 t->time.tm_mday = -1;
266
267 if (cmos->mon_alrm) {
268 if (((unsigned)t->time.tm_mon) <= 0x12)
269 t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
270 else
271 t->time.tm_mon = -1;
272 }
273 }
274 }
275 t->time.tm_year = -1;
276
277 t->enabled = !!(rtc_control & RTC_AIE);
278 t->pending = 0;
279
280 return 0;
281}
282
283static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
284{
285 unsigned char rtc_intr;
286
287 /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
288 * allegedly some older rtcs need that to handle irqs properly
289 */
290 rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
291
292 if (is_hpet_enabled())
293 return;
294
295 rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
296 if (is_intr(rtc_intr))
297 rtc_update_irq(cmos->rtc, 1, rtc_intr);
298}
299
300static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
301{
302 unsigned char rtc_control;
303
304 /* flush any pending IRQ status, notably for update irqs,
305 * before we enable new IRQs
306 */
307 rtc_control = CMOS_READ(RTC_CONTROL);
308 cmos_checkintr(cmos, rtc_control);
309
310 rtc_control |= mask;
311 CMOS_WRITE(rtc_control, RTC_CONTROL);
312 hpet_set_rtc_irq_bit(mask);
313
314 cmos_checkintr(cmos, rtc_control);
315}
316
317static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
318{
319 unsigned char rtc_control;
320
321 rtc_control = CMOS_READ(RTC_CONTROL);
322 rtc_control &= ~mask;
323 CMOS_WRITE(rtc_control, RTC_CONTROL);
324 hpet_mask_rtc_irq_bit(mask);
325
326 cmos_checkintr(cmos, rtc_control);
327}
328
329static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
330{
331 struct cmos_rtc *cmos = dev_get_drvdata(dev);
332 unsigned char mon, mday, hrs, min, sec, rtc_control;
333
334 if (!is_valid_irq(cmos->irq))
335 return -EIO;
336
337 mon = t->time.tm_mon + 1;
338 mday = t->time.tm_mday;
339 hrs = t->time.tm_hour;
340 min = t->time.tm_min;
341 sec = t->time.tm_sec;
342
343 rtc_control = CMOS_READ(RTC_CONTROL);
344 if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
345 /* Writing 0xff means "don't care" or "match all". */
346 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
347 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
348 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
349 min = (min < 60) ? bin2bcd(min) : 0xff;
350 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
351 }
352
353 spin_lock_irq(&rtc_lock);
354
355 /* next rtc irq must not be from previous alarm setting */
356 cmos_irq_disable(cmos, RTC_AIE);
357
358 /* update alarm */
359 CMOS_WRITE(hrs, RTC_HOURS_ALARM);
360 CMOS_WRITE(min, RTC_MINUTES_ALARM);
361 CMOS_WRITE(sec, RTC_SECONDS_ALARM);
362
363 /* the system may support an "enhanced" alarm */
364 if (cmos->day_alrm) {
365 CMOS_WRITE(mday, cmos->day_alrm);
366 if (cmos->mon_alrm)
367 CMOS_WRITE(mon, cmos->mon_alrm);
368 }
369
370 /* FIXME the HPET alarm glue currently ignores day_alrm
371 * and mon_alrm ...
372 */
373 hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
374
375 if (t->enabled)
376 cmos_irq_enable(cmos, RTC_AIE);
377
378 spin_unlock_irq(&rtc_lock);
379
380 cmos->alarm_expires = rtc_tm_to_time64(&t->time);
381
382 return 0;
383}
384
385static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
386{
387 struct cmos_rtc *cmos = dev_get_drvdata(dev);
388 unsigned long flags;
389
390 if (!is_valid_irq(cmos->irq))
391 return -EINVAL;
392
393 spin_lock_irqsave(&rtc_lock, flags);
394
395 if (enabled)
396 cmos_irq_enable(cmos, RTC_AIE);
397 else
398 cmos_irq_disable(cmos, RTC_AIE);
399
400 spin_unlock_irqrestore(&rtc_lock, flags);
401 return 0;
402}
403
404#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
405
406static int cmos_procfs(struct device *dev, struct seq_file *seq)
407{
408 struct cmos_rtc *cmos = dev_get_drvdata(dev);
409 unsigned char rtc_control, valid;
410
411 spin_lock_irq(&rtc_lock);
412 rtc_control = CMOS_READ(RTC_CONTROL);
413 valid = CMOS_READ(RTC_VALID);
414 spin_unlock_irq(&rtc_lock);
415
416 /* NOTE: at least ICH6 reports battery status using a different
417 * (non-RTC) bit; and SQWE is ignored on many current systems.
418 */
419 seq_printf(seq,
420 "periodic_IRQ\t: %s\n"
421 "update_IRQ\t: %s\n"
422 "HPET_emulated\t: %s\n"
423 // "square_wave\t: %s\n"
424 "BCD\t\t: %s\n"
425 "DST_enable\t: %s\n"
426 "periodic_freq\t: %d\n"
427 "batt_status\t: %s\n",
428 (rtc_control & RTC_PIE) ? "yes" : "no",
429 (rtc_control & RTC_UIE) ? "yes" : "no",
430 is_hpet_enabled() ? "yes" : "no",
431 // (rtc_control & RTC_SQWE) ? "yes" : "no",
432 (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
433 (rtc_control & RTC_DST_EN) ? "yes" : "no",
434 cmos->rtc->irq_freq,
435 (valid & RTC_VRT) ? "okay" : "dead");
436
437 return 0;
438}
439
440#else
441#define cmos_procfs NULL
442#endif
443
444static const struct rtc_class_ops cmos_rtc_ops = {
445 .read_time = cmos_read_time,
446 .set_time = cmos_set_time,
447 .read_alarm = cmos_read_alarm,
448 .set_alarm = cmos_set_alarm,
449 .proc = cmos_procfs,
450 .alarm_irq_enable = cmos_alarm_irq_enable,
451};
452
453/*----------------------------------------------------------------*/
454
455/*
456 * All these chips have at least 64 bytes of address space, shared by
457 * RTC registers and NVRAM. Most of those bytes of NVRAM are used
458 * by boot firmware. Modern chips have 128 or 256 bytes.
459 */
460
461#define NVRAM_OFFSET (RTC_REG_D + 1)
462
463static ssize_t
464cmos_nvram_read(struct file *filp, struct kobject *kobj,
465 struct bin_attribute *attr,
466 char *buf, loff_t off, size_t count)
467{
468 int retval;
469
470 off += NVRAM_OFFSET;
471 spin_lock_irq(&rtc_lock);
472 for (retval = 0; count; count--, off++, retval++) {
473 if (off < 128)
474 *buf++ = CMOS_READ(off);
475 else if (can_bank2)
476 *buf++ = cmos_read_bank2(off);
477 else
478 break;
479 }
480 spin_unlock_irq(&rtc_lock);
481
482 return retval;
483}
484
485static ssize_t
486cmos_nvram_write(struct file *filp, struct kobject *kobj,
487 struct bin_attribute *attr,
488 char *buf, loff_t off, size_t count)
489{
490 struct cmos_rtc *cmos;
491 int retval;
492
493 cmos = dev_get_drvdata(container_of(kobj, struct device, kobj));
494
495 /* NOTE: on at least PCs and Ataris, the boot firmware uses a
496 * checksum on part of the NVRAM data. That's currently ignored
497 * here. If userspace is smart enough to know what fields of
498 * NVRAM to update, updating checksums is also part of its job.
499 */
500 off += NVRAM_OFFSET;
501 spin_lock_irq(&rtc_lock);
502 for (retval = 0; count; count--, off++, retval++) {
503 /* don't trash RTC registers */
504 if (off == cmos->day_alrm
505 || off == cmos->mon_alrm
506 || off == cmos->century)
507 buf++;
508 else if (off < 128)
509 CMOS_WRITE(*buf++, off);
510 else if (can_bank2)
511 cmos_write_bank2(*buf++, off);
512 else
513 break;
514 }
515 spin_unlock_irq(&rtc_lock);
516
517 return retval;
518}
519
520static struct bin_attribute nvram = {
521 .attr = {
522 .name = "nvram",
523 .mode = S_IRUGO | S_IWUSR,
524 },
525
526 .read = cmos_nvram_read,
527 .write = cmos_nvram_write,
528 /* size gets set up later */
529};
530
531/*----------------------------------------------------------------*/
532
533static struct cmos_rtc cmos_rtc;
534
535static irqreturn_t cmos_interrupt(int irq, void *p)
536{
537 u8 irqstat;
538 u8 rtc_control;
539
540 spin_lock(&rtc_lock);
541
542 /* When the HPET interrupt handler calls us, the interrupt
543 * status is passed as arg1 instead of the irq number. But
544 * always clear irq status, even when HPET is in the way.
545 *
546 * Note that HPET and RTC are almost certainly out of phase,
547 * giving different IRQ status ...
548 */
549 irqstat = CMOS_READ(RTC_INTR_FLAGS);
550 rtc_control = CMOS_READ(RTC_CONTROL);
551 if (is_hpet_enabled())
552 irqstat = (unsigned long)irq & 0xF0;
553
554 /* If we were suspended, RTC_CONTROL may not be accurate since the
555 * bios may have cleared it.
556 */
557 if (!cmos_rtc.suspend_ctrl)
558 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
559 else
560 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
561
562 /* All Linux RTC alarms should be treated as if they were oneshot.
563 * Similar code may be needed in system wakeup paths, in case the
564 * alarm woke the system.
565 */
566 if (irqstat & RTC_AIE) {
567 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
568 rtc_control &= ~RTC_AIE;
569 CMOS_WRITE(rtc_control, RTC_CONTROL);
570 hpet_mask_rtc_irq_bit(RTC_AIE);
571 CMOS_READ(RTC_INTR_FLAGS);
572 }
573 spin_unlock(&rtc_lock);
574
575 if (is_intr(irqstat)) {
576 rtc_update_irq(p, 1, irqstat);
577 return IRQ_HANDLED;
578 } else
579 return IRQ_NONE;
580}
581
582#ifdef CONFIG_PNP
583#define INITSECTION
584
585#else
586#define INITSECTION __init
587#endif
588
589static int INITSECTION
590cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
591{
592 struct cmos_rtc_board_info *info = dev_get_platdata(dev);
593 int retval = 0;
594 unsigned char rtc_control;
595 unsigned address_space;
596 u32 flags = 0;
597
598 /* there can be only one ... */
599 if (cmos_rtc.dev)
600 return -EBUSY;
601
602 if (!ports)
603 return -ENODEV;
604
605 /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
606 *
607 * REVISIT non-x86 systems may instead use memory space resources
608 * (needing ioremap etc), not i/o space resources like this ...
609 */
610 if (RTC_IOMAPPED)
611 ports = request_region(ports->start, resource_size(ports),
612 driver_name);
613 else
614 ports = request_mem_region(ports->start, resource_size(ports),
615 driver_name);
616 if (!ports) {
617 dev_dbg(dev, "i/o registers already in use\n");
618 return -EBUSY;
619 }
620
621 cmos_rtc.irq = rtc_irq;
622 cmos_rtc.iomem = ports;
623
624 /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
625 * driver did, but don't reject unknown configs. Old hardware
626 * won't address 128 bytes. Newer chips have multiple banks,
627 * though they may not be listed in one I/O resource.
628 */
629#if defined(CONFIG_ATARI)
630 address_space = 64;
631#elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
632 || defined(__sparc__) || defined(__mips__) \
633 || defined(__powerpc__)
634 address_space = 128;
635#else
636#warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
637 address_space = 128;
638#endif
639 if (can_bank2 && ports->end > (ports->start + 1))
640 address_space = 256;
641
642 /* For ACPI systems extension info comes from the FADT. On others,
643 * board specific setup provides it as appropriate. Systems where
644 * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
645 * some almost-clones) can provide hooks to make that behave.
646 *
647 * Note that ACPI doesn't preclude putting these registers into
648 * "extended" areas of the chip, including some that we won't yet
649 * expect CMOS_READ and friends to handle.
650 */
651 if (info) {
652 if (info->flags)
653 flags = info->flags;
654 if (info->address_space)
655 address_space = info->address_space;
656
657 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
658 cmos_rtc.day_alrm = info->rtc_day_alarm;
659 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
660 cmos_rtc.mon_alrm = info->rtc_mon_alarm;
661 if (info->rtc_century && info->rtc_century < 128)
662 cmos_rtc.century = info->rtc_century;
663
664 if (info->wake_on && info->wake_off) {
665 cmos_rtc.wake_on = info->wake_on;
666 cmos_rtc.wake_off = info->wake_off;
667 }
668 }
669
670 cmos_rtc.dev = dev;
671 dev_set_drvdata(dev, &cmos_rtc);
672
673 cmos_rtc.rtc = rtc_device_register(driver_name, dev,
674 &cmos_rtc_ops, THIS_MODULE);
675 if (IS_ERR(cmos_rtc.rtc)) {
676 retval = PTR_ERR(cmos_rtc.rtc);
677 goto cleanup0;
678 }
679
680 rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
681
682 spin_lock_irq(&rtc_lock);
683
684 if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
685 /* force periodic irq to CMOS reset default of 1024Hz;
686 *
687 * REVISIT it's been reported that at least one x86_64 ALI
688 * mobo doesn't use 32KHz here ... for portability we might
689 * need to do something about other clock frequencies.
690 */
691 cmos_rtc.rtc->irq_freq = 1024;
692 hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
693 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
694 }
695
696 /* disable irqs */
697 if (is_valid_irq(rtc_irq))
698 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
699
700 rtc_control = CMOS_READ(RTC_CONTROL);
701
702 spin_unlock_irq(&rtc_lock);
703
704 /* FIXME:
705 * <asm-generic/rtc.h> doesn't know 12-hour mode either.
706 */
707 if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
708 dev_warn(dev, "only 24-hr supported\n");
709 retval = -ENXIO;
710 goto cleanup1;
711 }
712
713 if (is_valid_irq(rtc_irq)) {
714 irq_handler_t rtc_cmos_int_handler;
715
716 if (is_hpet_enabled()) {
717 rtc_cmos_int_handler = hpet_rtc_interrupt;
718 retval = hpet_register_irq_handler(cmos_interrupt);
719 if (retval) {
720 dev_warn(dev, "hpet_register_irq_handler "
721 " failed in rtc_init().");
722 goto cleanup1;
723 }
724 } else
725 rtc_cmos_int_handler = cmos_interrupt;
726
727 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
728 IRQF_SHARED, dev_name(&cmos_rtc.rtc->dev),
729 cmos_rtc.rtc);
730 if (retval < 0) {
731 dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
732 goto cleanup1;
733 }
734 }
735 hpet_rtc_timer_init();
736
737 /* export at least the first block of NVRAM */
738 nvram.size = address_space - NVRAM_OFFSET;
739 retval = sysfs_create_bin_file(&dev->kobj, &nvram);
740 if (retval < 0) {
741 dev_dbg(dev, "can't create nvram file? %d\n", retval);
742 goto cleanup2;
743 }
744
745 dev_info(dev, "%s%s, %zd bytes nvram%s\n",
746 !is_valid_irq(rtc_irq) ? "no alarms" :
747 cmos_rtc.mon_alrm ? "alarms up to one year" :
748 cmos_rtc.day_alrm ? "alarms up to one month" :
749 "alarms up to one day",
750 cmos_rtc.century ? ", y3k" : "",
751 nvram.size,
752 is_hpet_enabled() ? ", hpet irqs" : "");
753
754 return 0;
755
756cleanup2:
757 if (is_valid_irq(rtc_irq))
758 free_irq(rtc_irq, cmos_rtc.rtc);
759cleanup1:
760 cmos_rtc.dev = NULL;
761 rtc_device_unregister(cmos_rtc.rtc);
762cleanup0:
763 if (RTC_IOMAPPED)
764 release_region(ports->start, resource_size(ports));
765 else
766 release_mem_region(ports->start, resource_size(ports));
767 return retval;
768}
769
770static void cmos_do_shutdown(int rtc_irq)
771{
772 spin_lock_irq(&rtc_lock);
773 if (is_valid_irq(rtc_irq))
774 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
775 spin_unlock_irq(&rtc_lock);
776}
777
778static void __exit cmos_do_remove(struct device *dev)
779{
780 struct cmos_rtc *cmos = dev_get_drvdata(dev);
781 struct resource *ports;
782
783 cmos_do_shutdown(cmos->irq);
784
785 sysfs_remove_bin_file(&dev->kobj, &nvram);
786
787 if (is_valid_irq(cmos->irq)) {
788 free_irq(cmos->irq, cmos->rtc);
789 hpet_unregister_irq_handler(cmos_interrupt);
790 }
791
792 rtc_device_unregister(cmos->rtc);
793 cmos->rtc = NULL;
794
795 ports = cmos->iomem;
796 if (RTC_IOMAPPED)
797 release_region(ports->start, resource_size(ports));
798 else
799 release_mem_region(ports->start, resource_size(ports));
800 cmos->iomem = NULL;
801
802 cmos->dev = NULL;
803}
804
805static int cmos_aie_poweroff(struct device *dev)
806{
807 struct cmos_rtc *cmos = dev_get_drvdata(dev);
808 struct rtc_time now;
809 time64_t t_now;
810 int retval = 0;
811 unsigned char rtc_control;
812
813 if (!cmos->alarm_expires)
814 return -EINVAL;
815
816 spin_lock_irq(&rtc_lock);
817 rtc_control = CMOS_READ(RTC_CONTROL);
818 spin_unlock_irq(&rtc_lock);
819
820 /* We only care about the situation where AIE is disabled. */
821 if (rtc_control & RTC_AIE)
822 return -EBUSY;
823
824 cmos_read_time(dev, &now);
825 t_now = rtc_tm_to_time64(&now);
826
827 /*
828 * When enabling "RTC wake-up" in BIOS setup, the machine reboots
829 * automatically right after shutdown on some buggy boxes.
830 * This automatic rebooting issue won't happen when the alarm
831 * time is larger than now+1 seconds.
832 *
833 * If the alarm time is equal to now+1 seconds, the issue can be
834 * prevented by cancelling the alarm.
835 */
836 if (cmos->alarm_expires == t_now + 1) {
837 struct rtc_wkalrm alarm;
838
839 /* Cancel the AIE timer by configuring the past time. */
840 rtc_time64_to_tm(t_now - 1, &alarm.time);
841 alarm.enabled = 0;
842 retval = cmos_set_alarm(dev, &alarm);
843 } else if (cmos->alarm_expires > t_now + 1) {
844 retval = -EBUSY;
845 }
846
847 return retval;
848}
849
850#ifdef CONFIG_PM
851
852static int cmos_suspend(struct device *dev)
853{
854 struct cmos_rtc *cmos = dev_get_drvdata(dev);
855 unsigned char tmp;
856
857 /* only the alarm might be a wakeup event source */
858 spin_lock_irq(&rtc_lock);
859 cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
860 if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
861 unsigned char mask;
862
863 if (device_may_wakeup(dev))
864 mask = RTC_IRQMASK & ~RTC_AIE;
865 else
866 mask = RTC_IRQMASK;
867 tmp &= ~mask;
868 CMOS_WRITE(tmp, RTC_CONTROL);
869 hpet_mask_rtc_irq_bit(mask);
870
871 cmos_checkintr(cmos, tmp);
872 }
873 spin_unlock_irq(&rtc_lock);
874
875 if (tmp & RTC_AIE) {
876 cmos->enabled_wake = 1;
877 if (cmos->wake_on)
878 cmos->wake_on(dev);
879 else
880 enable_irq_wake(cmos->irq);
881 }
882
883 dev_dbg(dev, "suspend%s, ctrl %02x\n",
884 (tmp & RTC_AIE) ? ", alarm may wake" : "",
885 tmp);
886
887 return 0;
888}
889
890/* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
891 * after a detour through G3 "mechanical off", although the ACPI spec
892 * says wakeup should only work from G1/S4 "hibernate". To most users,
893 * distinctions between S4 and S5 are pointless. So when the hardware
894 * allows, don't draw that distinction.
895 */
896static inline int cmos_poweroff(struct device *dev)
897{
898 return cmos_suspend(dev);
899}
900
901#ifdef CONFIG_PM_SLEEP
902
903static int cmos_resume(struct device *dev)
904{
905 struct cmos_rtc *cmos = dev_get_drvdata(dev);
906 unsigned char tmp;
907
908 if (cmos->enabled_wake) {
909 if (cmos->wake_off)
910 cmos->wake_off(dev);
911 else
912 disable_irq_wake(cmos->irq);
913 cmos->enabled_wake = 0;
914 }
915
916 spin_lock_irq(&rtc_lock);
917 tmp = cmos->suspend_ctrl;
918 cmos->suspend_ctrl = 0;
919 /* re-enable any irqs previously active */
920 if (tmp & RTC_IRQMASK) {
921 unsigned char mask;
922
923 if (device_may_wakeup(dev))
924 hpet_rtc_timer_init();
925
926 do {
927 CMOS_WRITE(tmp, RTC_CONTROL);
928 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
929
930 mask = CMOS_READ(RTC_INTR_FLAGS);
931 mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
932 if (!is_hpet_enabled() || !is_intr(mask))
933 break;
934
935 /* force one-shot behavior if HPET blocked
936 * the wake alarm's irq
937 */
938 rtc_update_irq(cmos->rtc, 1, mask);
939 tmp &= ~RTC_AIE;
940 hpet_mask_rtc_irq_bit(RTC_AIE);
941 } while (mask & RTC_AIE);
942 }
943 spin_unlock_irq(&rtc_lock);
944
945 dev_dbg(dev, "resume, ctrl %02x\n", tmp);
946
947 return 0;
948}
949
950#endif
951#else
952
953static inline int cmos_poweroff(struct device *dev)
954{
955 return -ENOSYS;
956}
957
958#endif
959
960static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
961
962/*----------------------------------------------------------------*/
963
964/* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
965 * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
966 * probably list them in similar PNPBIOS tables; so PNP is more common.
967 *
968 * We don't use legacy "poke at the hardware" probing. Ancient PCs that
969 * predate even PNPBIOS should set up platform_bus devices.
970 */
971
972#ifdef CONFIG_ACPI
973
974#include <linux/acpi.h>
975
976static u32 rtc_handler(void *context)
977{
978 struct device *dev = context;
979
980 pm_wakeup_event(dev, 0);
981 acpi_clear_event(ACPI_EVENT_RTC);
982 acpi_disable_event(ACPI_EVENT_RTC, 0);
983 return ACPI_INTERRUPT_HANDLED;
984}
985
986static inline void rtc_wake_setup(struct device *dev)
987{
988 acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
989 /*
990 * After the RTC handler is installed, the Fixed_RTC event should
991 * be disabled. Only when the RTC alarm is set will it be enabled.
992 */
993 acpi_clear_event(ACPI_EVENT_RTC);
994 acpi_disable_event(ACPI_EVENT_RTC, 0);
995}
996
997static void rtc_wake_on(struct device *dev)
998{
999 acpi_clear_event(ACPI_EVENT_RTC);
1000 acpi_enable_event(ACPI_EVENT_RTC, 0);
1001}
1002
1003static void rtc_wake_off(struct device *dev)
1004{
1005 acpi_disable_event(ACPI_EVENT_RTC, 0);
1006}
1007
1008/* Every ACPI platform has a mc146818 compatible "cmos rtc". Here we find
1009 * its device node and pass extra config data. This helps its driver use
1010 * capabilities that the now-obsolete mc146818 didn't have, and informs it
1011 * that this board's RTC is wakeup-capable (per ACPI spec).
1012 */
1013static struct cmos_rtc_board_info acpi_rtc_info;
1014
1015static void cmos_wake_setup(struct device *dev)
1016{
1017 if (acpi_disabled)
1018 return;
1019
1020 rtc_wake_setup(dev);
1021 acpi_rtc_info.wake_on = rtc_wake_on;
1022 acpi_rtc_info.wake_off = rtc_wake_off;
1023
1024 /* workaround bug in some ACPI tables */
1025 if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1026 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1027 acpi_gbl_FADT.month_alarm);
1028 acpi_gbl_FADT.month_alarm = 0;
1029 }
1030
1031 acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1032 acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1033 acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1034
1035 /* NOTE: S4_RTC_WAKE is NOT currently useful to Linux */
1036 if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1037 dev_info(dev, "RTC can wake from S4\n");
1038
1039 dev->platform_data = &acpi_rtc_info;
1040
1041 /* RTC always wakes from S1/S2/S3, and often S4/STD */
1042 device_init_wakeup(dev, 1);
1043}
1044
1045#else
1046
1047static void cmos_wake_setup(struct device *dev)
1048{
1049}
1050
1051#endif
1052
1053#ifdef CONFIG_PNP
1054
1055#include <linux/pnp.h>
1056
1057static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1058{
1059 cmos_wake_setup(&pnp->dev);
1060
1061 if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0))
1062 /* Some machines contain a PNP entry for the RTC, but
1063 * don't define the IRQ. It should always be safe to
1064 * hardcode it in these cases
1065 */
1066 return cmos_do_probe(&pnp->dev,
1067 pnp_get_resource(pnp, IORESOURCE_IO, 0), 8);
1068 else
1069 return cmos_do_probe(&pnp->dev,
1070 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1071 pnp_irq(pnp, 0));
1072}
1073
1074static void __exit cmos_pnp_remove(struct pnp_dev *pnp)
1075{
1076 cmos_do_remove(&pnp->dev);
1077}
1078
1079static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1080{
1081 struct device *dev = &pnp->dev;
1082 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1083
1084 if (system_state == SYSTEM_POWER_OFF) {
1085 int retval = cmos_poweroff(dev);
1086
1087 if (cmos_aie_poweroff(dev) < 0 && !retval)
1088 return;
1089 }
1090
1091 cmos_do_shutdown(cmos->irq);
1092}
1093
1094static const struct pnp_device_id rtc_ids[] = {
1095 { .id = "PNP0b00", },
1096 { .id = "PNP0b01", },
1097 { .id = "PNP0b02", },
1098 { },
1099};
1100MODULE_DEVICE_TABLE(pnp, rtc_ids);
1101
1102static struct pnp_driver cmos_pnp_driver = {
1103 .name = (char *) driver_name,
1104 .id_table = rtc_ids,
1105 .probe = cmos_pnp_probe,
1106 .remove = __exit_p(cmos_pnp_remove),
1107 .shutdown = cmos_pnp_shutdown,
1108
1109 /* flag ensures resume() gets called, and stops syslog spam */
1110 .flags = PNP_DRIVER_RES_DO_NOT_CHANGE,
1111 .driver = {
1112 .pm = &cmos_pm_ops,
1113 },
1114};
1115
1116#endif /* CONFIG_PNP */
1117
1118#ifdef CONFIG_OF
1119static const struct of_device_id of_cmos_match[] = {
1120 {
1121 .compatible = "motorola,mc146818",
1122 },
1123 { },
1124};
1125MODULE_DEVICE_TABLE(of, of_cmos_match);
1126
1127static __init void cmos_of_init(struct platform_device *pdev)
1128{
1129 struct device_node *node = pdev->dev.of_node;
1130 struct rtc_time time;
1131 int ret;
1132 const __be32 *val;
1133
1134 if (!node)
1135 return;
1136
1137 val = of_get_property(node, "ctrl-reg", NULL);
1138 if (val)
1139 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1140
1141 val = of_get_property(node, "freq-reg", NULL);
1142 if (val)
1143 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1144
1145 get_rtc_time(&time);
1146 ret = rtc_valid_tm(&time);
1147 if (ret) {
1148 struct rtc_time def_time = {
1149 .tm_year = 1,
1150 .tm_mday = 1,
1151 };
1152 set_rtc_time(&def_time);
1153 }
1154}
1155#else
1156static inline void cmos_of_init(struct platform_device *pdev) {}
1157#endif
1158/*----------------------------------------------------------------*/
1159
1160/* Platform setup should have set up an RTC device, when PNP is
1161 * unavailable ... this could happen even on (older) PCs.
1162 */
1163
1164static int __init cmos_platform_probe(struct platform_device *pdev)
1165{
1166 struct resource *resource;
1167 int irq;
1168
1169 cmos_of_init(pdev);
1170 cmos_wake_setup(&pdev->dev);
1171
1172 if (RTC_IOMAPPED)
1173 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1174 else
1175 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1176 irq = platform_get_irq(pdev, 0);
1177 if (irq < 0)
1178 irq = -1;
1179
1180 return cmos_do_probe(&pdev->dev, resource, irq);
1181}
1182
1183static int __exit cmos_platform_remove(struct platform_device *pdev)
1184{
1185 cmos_do_remove(&pdev->dev);
1186 return 0;
1187}
1188
1189static void cmos_platform_shutdown(struct platform_device *pdev)
1190{
1191 struct device *dev = &pdev->dev;
1192 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1193
1194 if (system_state == SYSTEM_POWER_OFF) {
1195 int retval = cmos_poweroff(dev);
1196
1197 if (cmos_aie_poweroff(dev) < 0 && !retval)
1198 return;
1199 }
1200
1201 cmos_do_shutdown(cmos->irq);
1202}
1203
1204/* work with hotplug and coldplug */
1205MODULE_ALIAS("platform:rtc_cmos");
1206
1207static struct platform_driver cmos_platform_driver = {
1208 .remove = __exit_p(cmos_platform_remove),
1209 .shutdown = cmos_platform_shutdown,
1210 .driver = {
1211 .name = driver_name,
1212#ifdef CONFIG_PM
1213 .pm = &cmos_pm_ops,
1214#endif
1215 .of_match_table = of_match_ptr(of_cmos_match),
1216 }
1217};
1218
1219#ifdef CONFIG_PNP
1220static bool pnp_driver_registered;
1221#endif
1222static bool platform_driver_registered;
1223
1224static int __init cmos_init(void)
1225{
1226 int retval = 0;
1227
1228#ifdef CONFIG_PNP
1229 retval = pnp_register_driver(&cmos_pnp_driver);
1230 if (retval == 0)
1231 pnp_driver_registered = true;
1232#endif
1233
1234 if (!cmos_rtc.dev) {
1235 retval = platform_driver_probe(&cmos_platform_driver,
1236 cmos_platform_probe);
1237 if (retval == 0)
1238 platform_driver_registered = true;
1239 }
1240
1241 if (retval == 0)
1242 return 0;
1243
1244#ifdef CONFIG_PNP
1245 if (pnp_driver_registered)
1246 pnp_unregister_driver(&cmos_pnp_driver);
1247#endif
1248 return retval;
1249}
1250module_init(cmos_init);
1251
1252static void __exit cmos_exit(void)
1253{
1254#ifdef CONFIG_PNP
1255 if (pnp_driver_registered)
1256 pnp_unregister_driver(&cmos_pnp_driver);
1257#endif
1258 if (platform_driver_registered)
1259 platform_driver_unregister(&cmos_platform_driver);
1260}
1261module_exit(cmos_exit);
1262
1263
1264MODULE_AUTHOR("David Brownell");
1265MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1266MODULE_LICENSE("GPL");
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
45/* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
46#include <linux/mc146818rtc.h>
47
48struct cmos_rtc {
49 struct rtc_device *rtc;
50 struct device *dev;
51 int irq;
52 struct resource *iomem;
53 time64_t alarm_expires;
54
55 void (*wake_on)(struct device *);
56 void (*wake_off)(struct device *);
57
58 u8 enabled_wake;
59 u8 suspend_ctrl;
60
61 /* newer hardware extends the original register set */
62 u8 day_alrm;
63 u8 mon_alrm;
64 u8 century;
65
66 struct rtc_wkalrm saved_wkalrm;
67};
68
69/* both platform and pnp busses use negative numbers for invalid irqs */
70#define is_valid_irq(n) ((n) > 0)
71
72static const char driver_name[] = "rtc_cmos";
73
74/* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
75 * always mask it against the irq enable bits in RTC_CONTROL. Bit values
76 * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
77 */
78#define RTC_IRQMASK (RTC_PF | RTC_AF | RTC_UF)
79
80static inline int is_intr(u8 rtc_intr)
81{
82 if (!(rtc_intr & RTC_IRQF))
83 return 0;
84 return rtc_intr & RTC_IRQMASK;
85}
86
87/*----------------------------------------------------------------*/
88
89/* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
90 * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
91 * used in a broken "legacy replacement" mode. The breakage includes
92 * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
93 * other (better) use.
94 *
95 * When that broken mode is in use, platform glue provides a partial
96 * emulation of hardware RTC IRQ facilities using HPET #1. We don't
97 * want to use HPET for anything except those IRQs though...
98 */
99#ifdef CONFIG_HPET_EMULATE_RTC
100#include <asm/hpet.h>
101#else
102
103static inline int is_hpet_enabled(void)
104{
105 return 0;
106}
107
108static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
109{
110 return 0;
111}
112
113static inline int hpet_set_rtc_irq_bit(unsigned long mask)
114{
115 return 0;
116}
117
118static inline int
119hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
120{
121 return 0;
122}
123
124static inline int hpet_set_periodic_freq(unsigned long freq)
125{
126 return 0;
127}
128
129static inline int hpet_rtc_dropped_irq(void)
130{
131 return 0;
132}
133
134static inline int hpet_rtc_timer_init(void)
135{
136 return 0;
137}
138
139extern irq_handler_t hpet_rtc_interrupt;
140
141static inline int hpet_register_irq_handler(irq_handler_t handler)
142{
143 return 0;
144}
145
146static inline int hpet_unregister_irq_handler(irq_handler_t handler)
147{
148 return 0;
149}
150
151#endif
152
153/*----------------------------------------------------------------*/
154
155#ifdef RTC_PORT
156
157/* Most newer x86 systems have two register banks, the first used
158 * for RTC and NVRAM and the second only for NVRAM. Caller must
159 * own rtc_lock ... and we won't worry about access during NMI.
160 */
161#define can_bank2 true
162
163static inline unsigned char cmos_read_bank2(unsigned char addr)
164{
165 outb(addr, RTC_PORT(2));
166 return inb(RTC_PORT(3));
167}
168
169static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
170{
171 outb(addr, RTC_PORT(2));
172 outb(val, RTC_PORT(3));
173}
174
175#else
176
177#define can_bank2 false
178
179static inline unsigned char cmos_read_bank2(unsigned char addr)
180{
181 return 0;
182}
183
184static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
185{
186}
187
188#endif
189
190/*----------------------------------------------------------------*/
191
192static int cmos_read_time(struct device *dev, struct rtc_time *t)
193{
194 /*
195 * If pm_trace abused the RTC for storage, set the timespec to 0,
196 * which tells the caller that this RTC value is unusable.
197 */
198 if (!pm_trace_rtc_valid())
199 return -EIO;
200
201 /* REVISIT: if the clock has a "century" register, use
202 * that instead of the heuristic in mc146818_get_time().
203 * That'll make Y3K compatility (year > 2070) easy!
204 */
205 mc146818_get_time(t);
206 return 0;
207}
208
209static int cmos_set_time(struct device *dev, struct rtc_time *t)
210{
211 /* REVISIT: set the "century" register if available
212 *
213 * NOTE: this ignores the issue whereby updating the seconds
214 * takes effect exactly 500ms after we write the register.
215 * (Also queueing and other delays before we get this far.)
216 */
217 return mc146818_set_time(t);
218}
219
220static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
221{
222 struct cmos_rtc *cmos = dev_get_drvdata(dev);
223 unsigned char rtc_control;
224
225 if (!is_valid_irq(cmos->irq))
226 return -EIO;
227
228 /* Basic alarms only support hour, minute, and seconds fields.
229 * Some also support day and month, for alarms up to a year in
230 * the future.
231 */
232
233 spin_lock_irq(&rtc_lock);
234 t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
235 t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
236 t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
237
238 if (cmos->day_alrm) {
239 /* ignore upper bits on readback per ACPI spec */
240 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
241 if (!t->time.tm_mday)
242 t->time.tm_mday = -1;
243
244 if (cmos->mon_alrm) {
245 t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
246 if (!t->time.tm_mon)
247 t->time.tm_mon = -1;
248 }
249 }
250
251 rtc_control = CMOS_READ(RTC_CONTROL);
252 spin_unlock_irq(&rtc_lock);
253
254 if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
255 if (((unsigned)t->time.tm_sec) < 0x60)
256 t->time.tm_sec = bcd2bin(t->time.tm_sec);
257 else
258 t->time.tm_sec = -1;
259 if (((unsigned)t->time.tm_min) < 0x60)
260 t->time.tm_min = bcd2bin(t->time.tm_min);
261 else
262 t->time.tm_min = -1;
263 if (((unsigned)t->time.tm_hour) < 0x24)
264 t->time.tm_hour = bcd2bin(t->time.tm_hour);
265 else
266 t->time.tm_hour = -1;
267
268 if (cmos->day_alrm) {
269 if (((unsigned)t->time.tm_mday) <= 0x31)
270 t->time.tm_mday = bcd2bin(t->time.tm_mday);
271 else
272 t->time.tm_mday = -1;
273
274 if (cmos->mon_alrm) {
275 if (((unsigned)t->time.tm_mon) <= 0x12)
276 t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
277 else
278 t->time.tm_mon = -1;
279 }
280 }
281 }
282
283 t->enabled = !!(rtc_control & RTC_AIE);
284 t->pending = 0;
285
286 return 0;
287}
288
289static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
290{
291 unsigned char rtc_intr;
292
293 /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
294 * allegedly some older rtcs need that to handle irqs properly
295 */
296 rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
297
298 if (is_hpet_enabled())
299 return;
300
301 rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
302 if (is_intr(rtc_intr))
303 rtc_update_irq(cmos->rtc, 1, rtc_intr);
304}
305
306static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
307{
308 unsigned char rtc_control;
309
310 /* flush any pending IRQ status, notably for update irqs,
311 * before we enable new IRQs
312 */
313 rtc_control = CMOS_READ(RTC_CONTROL);
314 cmos_checkintr(cmos, rtc_control);
315
316 rtc_control |= mask;
317 CMOS_WRITE(rtc_control, RTC_CONTROL);
318 hpet_set_rtc_irq_bit(mask);
319
320 cmos_checkintr(cmos, rtc_control);
321}
322
323static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
324{
325 unsigned char rtc_control;
326
327 rtc_control = CMOS_READ(RTC_CONTROL);
328 rtc_control &= ~mask;
329 CMOS_WRITE(rtc_control, RTC_CONTROL);
330 hpet_mask_rtc_irq_bit(mask);
331
332 cmos_checkintr(cmos, rtc_control);
333}
334
335static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t)
336{
337 struct cmos_rtc *cmos = dev_get_drvdata(dev);
338 struct rtc_time now;
339
340 cmos_read_time(dev, &now);
341
342 if (!cmos->day_alrm) {
343 time64_t t_max_date;
344 time64_t t_alrm;
345
346 t_max_date = rtc_tm_to_time64(&now);
347 t_max_date += 24 * 60 * 60 - 1;
348 t_alrm = rtc_tm_to_time64(&t->time);
349 if (t_alrm > t_max_date) {
350 dev_err(dev,
351 "Alarms can be up to one day in the future\n");
352 return -EINVAL;
353 }
354 } else if (!cmos->mon_alrm) {
355 struct rtc_time max_date = now;
356 time64_t t_max_date;
357 time64_t t_alrm;
358 int max_mday;
359
360 if (max_date.tm_mon == 11) {
361 max_date.tm_mon = 0;
362 max_date.tm_year += 1;
363 } else {
364 max_date.tm_mon += 1;
365 }
366 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
367 if (max_date.tm_mday > max_mday)
368 max_date.tm_mday = max_mday;
369
370 t_max_date = rtc_tm_to_time64(&max_date);
371 t_max_date -= 1;
372 t_alrm = rtc_tm_to_time64(&t->time);
373 if (t_alrm > t_max_date) {
374 dev_err(dev,
375 "Alarms can be up to one month in the future\n");
376 return -EINVAL;
377 }
378 } else {
379 struct rtc_time max_date = now;
380 time64_t t_max_date;
381 time64_t t_alrm;
382 int max_mday;
383
384 max_date.tm_year += 1;
385 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
386 if (max_date.tm_mday > max_mday)
387 max_date.tm_mday = max_mday;
388
389 t_max_date = rtc_tm_to_time64(&max_date);
390 t_max_date -= 1;
391 t_alrm = rtc_tm_to_time64(&t->time);
392 if (t_alrm > t_max_date) {
393 dev_err(dev,
394 "Alarms can be up to one year in the future\n");
395 return -EINVAL;
396 }
397 }
398
399 return 0;
400}
401
402static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
403{
404 struct cmos_rtc *cmos = dev_get_drvdata(dev);
405 unsigned char mon, mday, hrs, min, sec, rtc_control;
406 int ret;
407
408 if (!is_valid_irq(cmos->irq))
409 return -EIO;
410
411 ret = cmos_validate_alarm(dev, t);
412 if (ret < 0)
413 return ret;
414
415 mon = t->time.tm_mon + 1;
416 mday = t->time.tm_mday;
417 hrs = t->time.tm_hour;
418 min = t->time.tm_min;
419 sec = t->time.tm_sec;
420
421 rtc_control = CMOS_READ(RTC_CONTROL);
422 if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
423 /* Writing 0xff means "don't care" or "match all". */
424 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
425 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
426 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
427 min = (min < 60) ? bin2bcd(min) : 0xff;
428 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
429 }
430
431 spin_lock_irq(&rtc_lock);
432
433 /* next rtc irq must not be from previous alarm setting */
434 cmos_irq_disable(cmos, RTC_AIE);
435
436 /* update alarm */
437 CMOS_WRITE(hrs, RTC_HOURS_ALARM);
438 CMOS_WRITE(min, RTC_MINUTES_ALARM);
439 CMOS_WRITE(sec, RTC_SECONDS_ALARM);
440
441 /* the system may support an "enhanced" alarm */
442 if (cmos->day_alrm) {
443 CMOS_WRITE(mday, cmos->day_alrm);
444 if (cmos->mon_alrm)
445 CMOS_WRITE(mon, cmos->mon_alrm);
446 }
447
448 /* FIXME the HPET alarm glue currently ignores day_alrm
449 * and mon_alrm ...
450 */
451 hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
452
453 if (t->enabled)
454 cmos_irq_enable(cmos, RTC_AIE);
455
456 spin_unlock_irq(&rtc_lock);
457
458 cmos->alarm_expires = rtc_tm_to_time64(&t->time);
459
460 return 0;
461}
462
463static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
464{
465 struct cmos_rtc *cmos = dev_get_drvdata(dev);
466 unsigned long flags;
467
468 if (!is_valid_irq(cmos->irq))
469 return -EINVAL;
470
471 spin_lock_irqsave(&rtc_lock, flags);
472
473 if (enabled)
474 cmos_irq_enable(cmos, RTC_AIE);
475 else
476 cmos_irq_disable(cmos, RTC_AIE);
477
478 spin_unlock_irqrestore(&rtc_lock, flags);
479 return 0;
480}
481
482#if IS_ENABLED(CONFIG_RTC_INTF_PROC)
483
484static int cmos_procfs(struct device *dev, struct seq_file *seq)
485{
486 struct cmos_rtc *cmos = dev_get_drvdata(dev);
487 unsigned char rtc_control, valid;
488
489 spin_lock_irq(&rtc_lock);
490 rtc_control = CMOS_READ(RTC_CONTROL);
491 valid = CMOS_READ(RTC_VALID);
492 spin_unlock_irq(&rtc_lock);
493
494 /* NOTE: at least ICH6 reports battery status using a different
495 * (non-RTC) bit; and SQWE is ignored on many current systems.
496 */
497 seq_printf(seq,
498 "periodic_IRQ\t: %s\n"
499 "update_IRQ\t: %s\n"
500 "HPET_emulated\t: %s\n"
501 // "square_wave\t: %s\n"
502 "BCD\t\t: %s\n"
503 "DST_enable\t: %s\n"
504 "periodic_freq\t: %d\n"
505 "batt_status\t: %s\n",
506 (rtc_control & RTC_PIE) ? "yes" : "no",
507 (rtc_control & RTC_UIE) ? "yes" : "no",
508 is_hpet_enabled() ? "yes" : "no",
509 // (rtc_control & RTC_SQWE) ? "yes" : "no",
510 (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
511 (rtc_control & RTC_DST_EN) ? "yes" : "no",
512 cmos->rtc->irq_freq,
513 (valid & RTC_VRT) ? "okay" : "dead");
514
515 return 0;
516}
517
518#else
519#define cmos_procfs NULL
520#endif
521
522static const struct rtc_class_ops cmos_rtc_ops = {
523 .read_time = cmos_read_time,
524 .set_time = cmos_set_time,
525 .read_alarm = cmos_read_alarm,
526 .set_alarm = cmos_set_alarm,
527 .proc = cmos_procfs,
528 .alarm_irq_enable = cmos_alarm_irq_enable,
529};
530
531/*----------------------------------------------------------------*/
532
533/*
534 * All these chips have at least 64 bytes of address space, shared by
535 * RTC registers and NVRAM. Most of those bytes of NVRAM are used
536 * by boot firmware. Modern chips have 128 or 256 bytes.
537 */
538
539#define NVRAM_OFFSET (RTC_REG_D + 1)
540
541static ssize_t
542cmos_nvram_read(struct file *filp, struct kobject *kobj,
543 struct bin_attribute *attr,
544 char *buf, loff_t off, size_t count)
545{
546 int retval;
547
548 off += NVRAM_OFFSET;
549 spin_lock_irq(&rtc_lock);
550 for (retval = 0; count; count--, off++, retval++) {
551 if (off < 128)
552 *buf++ = CMOS_READ(off);
553 else if (can_bank2)
554 *buf++ = cmos_read_bank2(off);
555 else
556 break;
557 }
558 spin_unlock_irq(&rtc_lock);
559
560 return retval;
561}
562
563static ssize_t
564cmos_nvram_write(struct file *filp, struct kobject *kobj,
565 struct bin_attribute *attr,
566 char *buf, loff_t off, size_t count)
567{
568 struct cmos_rtc *cmos;
569 int retval;
570
571 cmos = dev_get_drvdata(container_of(kobj, struct device, kobj));
572
573 /* NOTE: on at least PCs and Ataris, the boot firmware uses a
574 * checksum on part of the NVRAM data. That's currently ignored
575 * here. If userspace is smart enough to know what fields of
576 * NVRAM to update, updating checksums is also part of its job.
577 */
578 off += NVRAM_OFFSET;
579 spin_lock_irq(&rtc_lock);
580 for (retval = 0; count; count--, off++, retval++) {
581 /* don't trash RTC registers */
582 if (off == cmos->day_alrm
583 || off == cmos->mon_alrm
584 || off == cmos->century)
585 buf++;
586 else if (off < 128)
587 CMOS_WRITE(*buf++, off);
588 else if (can_bank2)
589 cmos_write_bank2(*buf++, off);
590 else
591 break;
592 }
593 spin_unlock_irq(&rtc_lock);
594
595 return retval;
596}
597
598static struct bin_attribute nvram = {
599 .attr = {
600 .name = "nvram",
601 .mode = S_IRUGO | S_IWUSR,
602 },
603
604 .read = cmos_nvram_read,
605 .write = cmos_nvram_write,
606 /* size gets set up later */
607};
608
609/*----------------------------------------------------------------*/
610
611static struct cmos_rtc cmos_rtc;
612
613static irqreturn_t cmos_interrupt(int irq, void *p)
614{
615 u8 irqstat;
616 u8 rtc_control;
617
618 spin_lock(&rtc_lock);
619
620 /* When the HPET interrupt handler calls us, the interrupt
621 * status is passed as arg1 instead of the irq number. But
622 * always clear irq status, even when HPET is in the way.
623 *
624 * Note that HPET and RTC are almost certainly out of phase,
625 * giving different IRQ status ...
626 */
627 irqstat = CMOS_READ(RTC_INTR_FLAGS);
628 rtc_control = CMOS_READ(RTC_CONTROL);
629 if (is_hpet_enabled())
630 irqstat = (unsigned long)irq & 0xF0;
631
632 /* If we were suspended, RTC_CONTROL may not be accurate since the
633 * bios may have cleared it.
634 */
635 if (!cmos_rtc.suspend_ctrl)
636 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
637 else
638 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
639
640 /* All Linux RTC alarms should be treated as if they were oneshot.
641 * Similar code may be needed in system wakeup paths, in case the
642 * alarm woke the system.
643 */
644 if (irqstat & RTC_AIE) {
645 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
646 rtc_control &= ~RTC_AIE;
647 CMOS_WRITE(rtc_control, RTC_CONTROL);
648 hpet_mask_rtc_irq_bit(RTC_AIE);
649 CMOS_READ(RTC_INTR_FLAGS);
650 }
651 spin_unlock(&rtc_lock);
652
653 if (is_intr(irqstat)) {
654 rtc_update_irq(p, 1, irqstat);
655 return IRQ_HANDLED;
656 } else
657 return IRQ_NONE;
658}
659
660#ifdef CONFIG_PNP
661#define INITSECTION
662
663#else
664#define INITSECTION __init
665#endif
666
667static int INITSECTION
668cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
669{
670 struct cmos_rtc_board_info *info = dev_get_platdata(dev);
671 int retval = 0;
672 unsigned char rtc_control;
673 unsigned address_space;
674 u32 flags = 0;
675
676 /* there can be only one ... */
677 if (cmos_rtc.dev)
678 return -EBUSY;
679
680 if (!ports)
681 return -ENODEV;
682
683 /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
684 *
685 * REVISIT non-x86 systems may instead use memory space resources
686 * (needing ioremap etc), not i/o space resources like this ...
687 */
688 if (RTC_IOMAPPED)
689 ports = request_region(ports->start, resource_size(ports),
690 driver_name);
691 else
692 ports = request_mem_region(ports->start, resource_size(ports),
693 driver_name);
694 if (!ports) {
695 dev_dbg(dev, "i/o registers already in use\n");
696 return -EBUSY;
697 }
698
699 cmos_rtc.irq = rtc_irq;
700 cmos_rtc.iomem = ports;
701
702 /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
703 * driver did, but don't reject unknown configs. Old hardware
704 * won't address 128 bytes. Newer chips have multiple banks,
705 * though they may not be listed in one I/O resource.
706 */
707#if defined(CONFIG_ATARI)
708 address_space = 64;
709#elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
710 || defined(__sparc__) || defined(__mips__) \
711 || defined(__powerpc__) || defined(CONFIG_MN10300)
712 address_space = 128;
713#else
714#warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
715 address_space = 128;
716#endif
717 if (can_bank2 && ports->end > (ports->start + 1))
718 address_space = 256;
719
720 /* For ACPI systems extension info comes from the FADT. On others,
721 * board specific setup provides it as appropriate. Systems where
722 * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
723 * some almost-clones) can provide hooks to make that behave.
724 *
725 * Note that ACPI doesn't preclude putting these registers into
726 * "extended" areas of the chip, including some that we won't yet
727 * expect CMOS_READ and friends to handle.
728 */
729 if (info) {
730 if (info->flags)
731 flags = info->flags;
732 if (info->address_space)
733 address_space = info->address_space;
734
735 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
736 cmos_rtc.day_alrm = info->rtc_day_alarm;
737 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
738 cmos_rtc.mon_alrm = info->rtc_mon_alarm;
739 if (info->rtc_century && info->rtc_century < 128)
740 cmos_rtc.century = info->rtc_century;
741
742 if (info->wake_on && info->wake_off) {
743 cmos_rtc.wake_on = info->wake_on;
744 cmos_rtc.wake_off = info->wake_off;
745 }
746 }
747
748 cmos_rtc.dev = dev;
749 dev_set_drvdata(dev, &cmos_rtc);
750
751 cmos_rtc.rtc = rtc_device_register(driver_name, dev,
752 &cmos_rtc_ops, THIS_MODULE);
753 if (IS_ERR(cmos_rtc.rtc)) {
754 retval = PTR_ERR(cmos_rtc.rtc);
755 goto cleanup0;
756 }
757
758 rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
759
760 spin_lock_irq(&rtc_lock);
761
762 if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
763 /* force periodic irq to CMOS reset default of 1024Hz;
764 *
765 * REVISIT it's been reported that at least one x86_64 ALI
766 * mobo doesn't use 32KHz here ... for portability we might
767 * need to do something about other clock frequencies.
768 */
769 cmos_rtc.rtc->irq_freq = 1024;
770 hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
771 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
772 }
773
774 /* disable irqs */
775 if (is_valid_irq(rtc_irq))
776 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
777
778 rtc_control = CMOS_READ(RTC_CONTROL);
779
780 spin_unlock_irq(&rtc_lock);
781
782 if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
783 dev_warn(dev, "only 24-hr supported\n");
784 retval = -ENXIO;
785 goto cleanup1;
786 }
787
788 hpet_rtc_timer_init();
789
790 if (is_valid_irq(rtc_irq)) {
791 irq_handler_t rtc_cmos_int_handler;
792
793 if (is_hpet_enabled()) {
794 rtc_cmos_int_handler = hpet_rtc_interrupt;
795 retval = hpet_register_irq_handler(cmos_interrupt);
796 if (retval) {
797 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
798 dev_warn(dev, "hpet_register_irq_handler "
799 " failed in rtc_init().");
800 goto cleanup1;
801 }
802 } else
803 rtc_cmos_int_handler = cmos_interrupt;
804
805 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
806 IRQF_SHARED, dev_name(&cmos_rtc.rtc->dev),
807 cmos_rtc.rtc);
808 if (retval < 0) {
809 dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
810 goto cleanup1;
811 }
812 }
813
814 /* export at least the first block of NVRAM */
815 nvram.size = address_space - NVRAM_OFFSET;
816 retval = sysfs_create_bin_file(&dev->kobj, &nvram);
817 if (retval < 0) {
818 dev_dbg(dev, "can't create nvram file? %d\n", retval);
819 goto cleanup2;
820 }
821
822 dev_info(dev, "%s%s, %zd bytes nvram%s\n",
823 !is_valid_irq(rtc_irq) ? "no alarms" :
824 cmos_rtc.mon_alrm ? "alarms up to one year" :
825 cmos_rtc.day_alrm ? "alarms up to one month" :
826 "alarms up to one day",
827 cmos_rtc.century ? ", y3k" : "",
828 nvram.size,
829 is_hpet_enabled() ? ", hpet irqs" : "");
830
831 return 0;
832
833cleanup2:
834 if (is_valid_irq(rtc_irq))
835 free_irq(rtc_irq, cmos_rtc.rtc);
836cleanup1:
837 cmos_rtc.dev = NULL;
838 rtc_device_unregister(cmos_rtc.rtc);
839cleanup0:
840 if (RTC_IOMAPPED)
841 release_region(ports->start, resource_size(ports));
842 else
843 release_mem_region(ports->start, resource_size(ports));
844 return retval;
845}
846
847static void cmos_do_shutdown(int rtc_irq)
848{
849 spin_lock_irq(&rtc_lock);
850 if (is_valid_irq(rtc_irq))
851 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
852 spin_unlock_irq(&rtc_lock);
853}
854
855static void cmos_do_remove(struct device *dev)
856{
857 struct cmos_rtc *cmos = dev_get_drvdata(dev);
858 struct resource *ports;
859
860 cmos_do_shutdown(cmos->irq);
861
862 sysfs_remove_bin_file(&dev->kobj, &nvram);
863
864 if (is_valid_irq(cmos->irq)) {
865 free_irq(cmos->irq, cmos->rtc);
866 hpet_unregister_irq_handler(cmos_interrupt);
867 }
868
869 rtc_device_unregister(cmos->rtc);
870 cmos->rtc = NULL;
871
872 ports = cmos->iomem;
873 if (RTC_IOMAPPED)
874 release_region(ports->start, resource_size(ports));
875 else
876 release_mem_region(ports->start, resource_size(ports));
877 cmos->iomem = NULL;
878
879 cmos->dev = NULL;
880}
881
882static int cmos_aie_poweroff(struct device *dev)
883{
884 struct cmos_rtc *cmos = dev_get_drvdata(dev);
885 struct rtc_time now;
886 time64_t t_now;
887 int retval = 0;
888 unsigned char rtc_control;
889
890 if (!cmos->alarm_expires)
891 return -EINVAL;
892
893 spin_lock_irq(&rtc_lock);
894 rtc_control = CMOS_READ(RTC_CONTROL);
895 spin_unlock_irq(&rtc_lock);
896
897 /* We only care about the situation where AIE is disabled. */
898 if (rtc_control & RTC_AIE)
899 return -EBUSY;
900
901 cmos_read_time(dev, &now);
902 t_now = rtc_tm_to_time64(&now);
903
904 /*
905 * When enabling "RTC wake-up" in BIOS setup, the machine reboots
906 * automatically right after shutdown on some buggy boxes.
907 * This automatic rebooting issue won't happen when the alarm
908 * time is larger than now+1 seconds.
909 *
910 * If the alarm time is equal to now+1 seconds, the issue can be
911 * prevented by cancelling the alarm.
912 */
913 if (cmos->alarm_expires == t_now + 1) {
914 struct rtc_wkalrm alarm;
915
916 /* Cancel the AIE timer by configuring the past time. */
917 rtc_time64_to_tm(t_now - 1, &alarm.time);
918 alarm.enabled = 0;
919 retval = cmos_set_alarm(dev, &alarm);
920 } else if (cmos->alarm_expires > t_now + 1) {
921 retval = -EBUSY;
922 }
923
924 return retval;
925}
926
927static int cmos_suspend(struct device *dev)
928{
929 struct cmos_rtc *cmos = dev_get_drvdata(dev);
930 unsigned char tmp;
931
932 /* only the alarm might be a wakeup event source */
933 spin_lock_irq(&rtc_lock);
934 cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
935 if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
936 unsigned char mask;
937
938 if (device_may_wakeup(dev))
939 mask = RTC_IRQMASK & ~RTC_AIE;
940 else
941 mask = RTC_IRQMASK;
942 tmp &= ~mask;
943 CMOS_WRITE(tmp, RTC_CONTROL);
944 hpet_mask_rtc_irq_bit(mask);
945
946 cmos_checkintr(cmos, tmp);
947 }
948 spin_unlock_irq(&rtc_lock);
949
950 if (tmp & RTC_AIE) {
951 cmos->enabled_wake = 1;
952 if (cmos->wake_on)
953 cmos->wake_on(dev);
954 else
955 enable_irq_wake(cmos->irq);
956 }
957
958 cmos_read_alarm(dev, &cmos->saved_wkalrm);
959
960 dev_dbg(dev, "suspend%s, ctrl %02x\n",
961 (tmp & RTC_AIE) ? ", alarm may wake" : "",
962 tmp);
963
964 return 0;
965}
966
967/* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
968 * after a detour through G3 "mechanical off", although the ACPI spec
969 * says wakeup should only work from G1/S4 "hibernate". To most users,
970 * distinctions between S4 and S5 are pointless. So when the hardware
971 * allows, don't draw that distinction.
972 */
973static inline int cmos_poweroff(struct device *dev)
974{
975 if (!IS_ENABLED(CONFIG_PM))
976 return -ENOSYS;
977
978 return cmos_suspend(dev);
979}
980
981static void cmos_check_wkalrm(struct device *dev)
982{
983 struct cmos_rtc *cmos = dev_get_drvdata(dev);
984 struct rtc_wkalrm current_alarm;
985 time64_t t_current_expires;
986 time64_t t_saved_expires;
987
988 cmos_read_alarm(dev, ¤t_alarm);
989 t_current_expires = rtc_tm_to_time64(¤t_alarm.time);
990 t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
991 if (t_current_expires != t_saved_expires ||
992 cmos->saved_wkalrm.enabled != current_alarm.enabled) {
993 cmos_set_alarm(dev, &cmos->saved_wkalrm);
994 }
995}
996
997static void cmos_check_acpi_rtc_status(struct device *dev,
998 unsigned char *rtc_control);
999
1000static int __maybe_unused cmos_resume(struct device *dev)
1001{
1002 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1003 unsigned char tmp;
1004
1005 if (cmos->enabled_wake) {
1006 if (cmos->wake_off)
1007 cmos->wake_off(dev);
1008 else
1009 disable_irq_wake(cmos->irq);
1010 cmos->enabled_wake = 0;
1011 }
1012
1013 /* The BIOS might have changed the alarm, restore it */
1014 cmos_check_wkalrm(dev);
1015
1016 spin_lock_irq(&rtc_lock);
1017 tmp = cmos->suspend_ctrl;
1018 cmos->suspend_ctrl = 0;
1019 /* re-enable any irqs previously active */
1020 if (tmp & RTC_IRQMASK) {
1021 unsigned char mask;
1022
1023 if (device_may_wakeup(dev))
1024 hpet_rtc_timer_init();
1025
1026 do {
1027 CMOS_WRITE(tmp, RTC_CONTROL);
1028 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1029
1030 mask = CMOS_READ(RTC_INTR_FLAGS);
1031 mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1032 if (!is_hpet_enabled() || !is_intr(mask))
1033 break;
1034
1035 /* force one-shot behavior if HPET blocked
1036 * the wake alarm's irq
1037 */
1038 rtc_update_irq(cmos->rtc, 1, mask);
1039 tmp &= ~RTC_AIE;
1040 hpet_mask_rtc_irq_bit(RTC_AIE);
1041 } while (mask & RTC_AIE);
1042
1043 if (tmp & RTC_AIE)
1044 cmos_check_acpi_rtc_status(dev, &tmp);
1045 }
1046 spin_unlock_irq(&rtc_lock);
1047
1048 dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1049
1050 return 0;
1051}
1052
1053static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1054
1055/*----------------------------------------------------------------*/
1056
1057/* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1058 * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1059 * probably list them in similar PNPBIOS tables; so PNP is more common.
1060 *
1061 * We don't use legacy "poke at the hardware" probing. Ancient PCs that
1062 * predate even PNPBIOS should set up platform_bus devices.
1063 */
1064
1065#ifdef CONFIG_ACPI
1066
1067#include <linux/acpi.h>
1068
1069static u32 rtc_handler(void *context)
1070{
1071 struct device *dev = context;
1072 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1073 unsigned char rtc_control = 0;
1074 unsigned char rtc_intr;
1075 unsigned long flags;
1076
1077 spin_lock_irqsave(&rtc_lock, flags);
1078 if (cmos_rtc.suspend_ctrl)
1079 rtc_control = CMOS_READ(RTC_CONTROL);
1080 if (rtc_control & RTC_AIE) {
1081 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1082 CMOS_WRITE(rtc_control, RTC_CONTROL);
1083 rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1084 rtc_update_irq(cmos->rtc, 1, rtc_intr);
1085 }
1086 spin_unlock_irqrestore(&rtc_lock, flags);
1087
1088 pm_wakeup_event(dev, 0);
1089 acpi_clear_event(ACPI_EVENT_RTC);
1090 acpi_disable_event(ACPI_EVENT_RTC, 0);
1091 return ACPI_INTERRUPT_HANDLED;
1092}
1093
1094static inline void rtc_wake_setup(struct device *dev)
1095{
1096 acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1097 /*
1098 * After the RTC handler is installed, the Fixed_RTC event should
1099 * be disabled. Only when the RTC alarm is set will it be enabled.
1100 */
1101 acpi_clear_event(ACPI_EVENT_RTC);
1102 acpi_disable_event(ACPI_EVENT_RTC, 0);
1103}
1104
1105static void rtc_wake_on(struct device *dev)
1106{
1107 acpi_clear_event(ACPI_EVENT_RTC);
1108 acpi_enable_event(ACPI_EVENT_RTC, 0);
1109}
1110
1111static void rtc_wake_off(struct device *dev)
1112{
1113 acpi_disable_event(ACPI_EVENT_RTC, 0);
1114}
1115
1116/* Every ACPI platform has a mc146818 compatible "cmos rtc". Here we find
1117 * its device node and pass extra config data. This helps its driver use
1118 * capabilities that the now-obsolete mc146818 didn't have, and informs it
1119 * that this board's RTC is wakeup-capable (per ACPI spec).
1120 */
1121static struct cmos_rtc_board_info acpi_rtc_info;
1122
1123static void cmos_wake_setup(struct device *dev)
1124{
1125 if (acpi_disabled)
1126 return;
1127
1128 rtc_wake_setup(dev);
1129 acpi_rtc_info.wake_on = rtc_wake_on;
1130 acpi_rtc_info.wake_off = rtc_wake_off;
1131
1132 /* workaround bug in some ACPI tables */
1133 if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1134 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1135 acpi_gbl_FADT.month_alarm);
1136 acpi_gbl_FADT.month_alarm = 0;
1137 }
1138
1139 acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1140 acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1141 acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1142
1143 /* NOTE: S4_RTC_WAKE is NOT currently useful to Linux */
1144 if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1145 dev_info(dev, "RTC can wake from S4\n");
1146
1147 dev->platform_data = &acpi_rtc_info;
1148
1149 /* RTC always wakes from S1/S2/S3, and often S4/STD */
1150 device_init_wakeup(dev, 1);
1151}
1152
1153static void cmos_check_acpi_rtc_status(struct device *dev,
1154 unsigned char *rtc_control)
1155{
1156 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1157 acpi_event_status rtc_status;
1158 acpi_status status;
1159
1160 if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1161 return;
1162
1163 status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1164 if (ACPI_FAILURE(status)) {
1165 dev_err(dev, "Could not get RTC status\n");
1166 } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1167 unsigned char mask;
1168 *rtc_control &= ~RTC_AIE;
1169 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1170 mask = CMOS_READ(RTC_INTR_FLAGS);
1171 rtc_update_irq(cmos->rtc, 1, mask);
1172 }
1173}
1174
1175#else
1176
1177static void cmos_wake_setup(struct device *dev)
1178{
1179}
1180
1181static void cmos_check_acpi_rtc_status(struct device *dev,
1182 unsigned char *rtc_control)
1183{
1184}
1185
1186#endif
1187
1188#ifdef CONFIG_PNP
1189
1190#include <linux/pnp.h>
1191
1192static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1193{
1194 cmos_wake_setup(&pnp->dev);
1195
1196 if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0))
1197 /* Some machines contain a PNP entry for the RTC, but
1198 * don't define the IRQ. It should always be safe to
1199 * hardcode it in these cases
1200 */
1201 return cmos_do_probe(&pnp->dev,
1202 pnp_get_resource(pnp, IORESOURCE_IO, 0), 8);
1203 else
1204 return cmos_do_probe(&pnp->dev,
1205 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1206 pnp_irq(pnp, 0));
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 struct rtc_time time;
1266 int ret;
1267 const __be32 *val;
1268
1269 if (!node)
1270 return;
1271
1272 val = of_get_property(node, "ctrl-reg", NULL);
1273 if (val)
1274 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1275
1276 val = of_get_property(node, "freq-reg", NULL);
1277 if (val)
1278 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1279
1280 cmos_read_time(&pdev->dev, &time);
1281 ret = rtc_valid_tm(&time);
1282 if (ret) {
1283 struct rtc_time def_time = {
1284 .tm_year = 1,
1285 .tm_mday = 1,
1286 };
1287 cmos_set_time(&pdev->dev, &def_time);
1288 }
1289}
1290#else
1291static inline void cmos_of_init(struct platform_device *pdev) {}
1292#endif
1293/*----------------------------------------------------------------*/
1294
1295/* Platform setup should have set up an RTC device, when PNP is
1296 * unavailable ... this could happen even on (older) PCs.
1297 */
1298
1299static int __init cmos_platform_probe(struct platform_device *pdev)
1300{
1301 struct resource *resource;
1302 int irq;
1303
1304 cmos_of_init(pdev);
1305 cmos_wake_setup(&pdev->dev);
1306
1307 if (RTC_IOMAPPED)
1308 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1309 else
1310 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1311 irq = platform_get_irq(pdev, 0);
1312 if (irq < 0)
1313 irq = -1;
1314
1315 return cmos_do_probe(&pdev->dev, resource, irq);
1316}
1317
1318static int cmos_platform_remove(struct platform_device *pdev)
1319{
1320 cmos_do_remove(&pdev->dev);
1321 return 0;
1322}
1323
1324static void cmos_platform_shutdown(struct platform_device *pdev)
1325{
1326 struct device *dev = &pdev->dev;
1327 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1328
1329 if (system_state == SYSTEM_POWER_OFF) {
1330 int retval = cmos_poweroff(dev);
1331
1332 if (cmos_aie_poweroff(dev) < 0 && !retval)
1333 return;
1334 }
1335
1336 cmos_do_shutdown(cmos->irq);
1337}
1338
1339/* work with hotplug and coldplug */
1340MODULE_ALIAS("platform:rtc_cmos");
1341
1342static struct platform_driver cmos_platform_driver = {
1343 .remove = cmos_platform_remove,
1344 .shutdown = cmos_platform_shutdown,
1345 .driver = {
1346 .name = driver_name,
1347 .pm = &cmos_pm_ops,
1348 .of_match_table = of_match_ptr(of_cmos_match),
1349 }
1350};
1351
1352#ifdef CONFIG_PNP
1353static bool pnp_driver_registered;
1354#endif
1355static bool platform_driver_registered;
1356
1357static int __init cmos_init(void)
1358{
1359 int retval = 0;
1360
1361#ifdef CONFIG_PNP
1362 retval = pnp_register_driver(&cmos_pnp_driver);
1363 if (retval == 0)
1364 pnp_driver_registered = true;
1365#endif
1366
1367 if (!cmos_rtc.dev) {
1368 retval = platform_driver_probe(&cmos_platform_driver,
1369 cmos_platform_probe);
1370 if (retval == 0)
1371 platform_driver_registered = true;
1372 }
1373
1374 if (retval == 0)
1375 return 0;
1376
1377#ifdef CONFIG_PNP
1378 if (pnp_driver_registered)
1379 pnp_unregister_driver(&cmos_pnp_driver);
1380#endif
1381 return retval;
1382}
1383module_init(cmos_init);
1384
1385static void __exit cmos_exit(void)
1386{
1387#ifdef CONFIG_PNP
1388 if (pnp_driver_registered)
1389 pnp_unregister_driver(&cmos_pnp_driver);
1390#endif
1391 if (platform_driver_registered)
1392 platform_driver_unregister(&cmos_platform_driver);
1393}
1394module_exit(cmos_exit);
1395
1396
1397MODULE_AUTHOR("David Brownell");
1398MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1399MODULE_LICENSE("GPL");