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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#include <linux/kernel.h>
32#include <linux/module.h>
33#include <linux/init.h>
34#include <linux/interrupt.h>
35#include <linux/spinlock.h>
36#include <linux/platform_device.h>
37#include <linux/log2.h>
38#include <linux/pm.h>
39#include <linux/of.h>
40#include <linux/of_platform.h>
41#include <linux/dmi.h>
42
43/* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
44#include <asm-generic/rtc.h>
45
46struct cmos_rtc {
47 struct rtc_device *rtc;
48 struct device *dev;
49 int irq;
50 struct resource *iomem;
51
52 void (*wake_on)(struct device *);
53 void (*wake_off)(struct device *);
54
55 u8 enabled_wake;
56 u8 suspend_ctrl;
57
58 /* newer hardware extends the original register set */
59 u8 day_alrm;
60 u8 mon_alrm;
61 u8 century;
62};
63
64/* both platform and pnp busses use negative numbers for invalid irqs */
65#define is_valid_irq(n) ((n) > 0)
66
67static const char driver_name[] = "rtc_cmos";
68
69/* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
70 * always mask it against the irq enable bits in RTC_CONTROL. Bit values
71 * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
72 */
73#define RTC_IRQMASK (RTC_PF | RTC_AF | RTC_UF)
74
75static inline int is_intr(u8 rtc_intr)
76{
77 if (!(rtc_intr & RTC_IRQF))
78 return 0;
79 return rtc_intr & RTC_IRQMASK;
80}
81
82/*----------------------------------------------------------------*/
83
84/* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
85 * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
86 * used in a broken "legacy replacement" mode. The breakage includes
87 * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
88 * other (better) use.
89 *
90 * When that broken mode is in use, platform glue provides a partial
91 * emulation of hardware RTC IRQ facilities using HPET #1. We don't
92 * want to use HPET for anything except those IRQs though...
93 */
94#ifdef CONFIG_HPET_EMULATE_RTC
95#include <asm/hpet.h>
96#else
97
98static inline int is_hpet_enabled(void)
99{
100 return 0;
101}
102
103static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
104{
105 return 0;
106}
107
108static inline int hpet_set_rtc_irq_bit(unsigned long mask)
109{
110 return 0;
111}
112
113static inline int
114hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
115{
116 return 0;
117}
118
119static inline int hpet_set_periodic_freq(unsigned long freq)
120{
121 return 0;
122}
123
124static inline int hpet_rtc_dropped_irq(void)
125{
126 return 0;
127}
128
129static inline int hpet_rtc_timer_init(void)
130{
131 return 0;
132}
133
134extern irq_handler_t hpet_rtc_interrupt;
135
136static inline int hpet_register_irq_handler(irq_handler_t handler)
137{
138 return 0;
139}
140
141static inline int hpet_unregister_irq_handler(irq_handler_t handler)
142{
143 return 0;
144}
145
146#endif
147
148/*----------------------------------------------------------------*/
149
150#ifdef RTC_PORT
151
152/* Most newer x86 systems have two register banks, the first used
153 * for RTC and NVRAM and the second only for NVRAM. Caller must
154 * own rtc_lock ... and we won't worry about access during NMI.
155 */
156#define can_bank2 true
157
158static inline unsigned char cmos_read_bank2(unsigned char addr)
159{
160 outb(addr, RTC_PORT(2));
161 return inb(RTC_PORT(3));
162}
163
164static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
165{
166 outb(addr, RTC_PORT(2));
167 outb(val, RTC_PORT(3));
168}
169
170#else
171
172#define can_bank2 false
173
174static inline unsigned char cmos_read_bank2(unsigned char addr)
175{
176 return 0;
177}
178
179static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
180{
181}
182
183#endif
184
185/*----------------------------------------------------------------*/
186
187static int cmos_read_time(struct device *dev, struct rtc_time *t)
188{
189 /* REVISIT: if the clock has a "century" register, use
190 * that instead of the heuristic in get_rtc_time().
191 * That'll make Y3K compatility (year > 2070) easy!
192 */
193 get_rtc_time(t);
194 return 0;
195}
196
197static int cmos_set_time(struct device *dev, struct rtc_time *t)
198{
199 /* REVISIT: set the "century" register if available
200 *
201 * NOTE: this ignores the issue whereby updating the seconds
202 * takes effect exactly 500ms after we write the register.
203 * (Also queueing and other delays before we get this far.)
204 */
205 return set_rtc_time(t);
206}
207
208static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
209{
210 struct cmos_rtc *cmos = dev_get_drvdata(dev);
211 unsigned char rtc_control;
212
213 if (!is_valid_irq(cmos->irq))
214 return -EIO;
215
216 /* Basic alarms only support hour, minute, and seconds fields.
217 * Some also support day and month, for alarms up to a year in
218 * the future.
219 */
220 t->time.tm_mday = -1;
221 t->time.tm_mon = -1;
222
223 spin_lock_irq(&rtc_lock);
224 t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
225 t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
226 t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
227
228 if (cmos->day_alrm) {
229 /* ignore upper bits on readback per ACPI spec */
230 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
231 if (!t->time.tm_mday)
232 t->time.tm_mday = -1;
233
234 if (cmos->mon_alrm) {
235 t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
236 if (!t->time.tm_mon)
237 t->time.tm_mon = -1;
238 }
239 }
240
241 rtc_control = CMOS_READ(RTC_CONTROL);
242 spin_unlock_irq(&rtc_lock);
243
244 if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
245 if (((unsigned)t->time.tm_sec) < 0x60)
246 t->time.tm_sec = bcd2bin(t->time.tm_sec);
247 else
248 t->time.tm_sec = -1;
249 if (((unsigned)t->time.tm_min) < 0x60)
250 t->time.tm_min = bcd2bin(t->time.tm_min);
251 else
252 t->time.tm_min = -1;
253 if (((unsigned)t->time.tm_hour) < 0x24)
254 t->time.tm_hour = bcd2bin(t->time.tm_hour);
255 else
256 t->time.tm_hour = -1;
257
258 if (cmos->day_alrm) {
259 if (((unsigned)t->time.tm_mday) <= 0x31)
260 t->time.tm_mday = bcd2bin(t->time.tm_mday);
261 else
262 t->time.tm_mday = -1;
263
264 if (cmos->mon_alrm) {
265 if (((unsigned)t->time.tm_mon) <= 0x12)
266 t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
267 else
268 t->time.tm_mon = -1;
269 }
270 }
271 }
272 t->time.tm_year = -1;
273
274 t->enabled = !!(rtc_control & RTC_AIE);
275 t->pending = 0;
276
277 return 0;
278}
279
280static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
281{
282 unsigned char rtc_intr;
283
284 /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
285 * allegedly some older rtcs need that to handle irqs properly
286 */
287 rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
288
289 if (is_hpet_enabled())
290 return;
291
292 rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
293 if (is_intr(rtc_intr))
294 rtc_update_irq(cmos->rtc, 1, rtc_intr);
295}
296
297static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
298{
299 unsigned char rtc_control;
300
301 /* flush any pending IRQ status, notably for update irqs,
302 * before we enable new IRQs
303 */
304 rtc_control = CMOS_READ(RTC_CONTROL);
305 cmos_checkintr(cmos, rtc_control);
306
307 rtc_control |= mask;
308 CMOS_WRITE(rtc_control, RTC_CONTROL);
309 hpet_set_rtc_irq_bit(mask);
310
311 cmos_checkintr(cmos, rtc_control);
312}
313
314static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
315{
316 unsigned char rtc_control;
317
318 rtc_control = CMOS_READ(RTC_CONTROL);
319 rtc_control &= ~mask;
320 CMOS_WRITE(rtc_control, RTC_CONTROL);
321 hpet_mask_rtc_irq_bit(mask);
322
323 cmos_checkintr(cmos, rtc_control);
324}
325
326static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
327{
328 struct cmos_rtc *cmos = dev_get_drvdata(dev);
329 unsigned char mon, mday, hrs, min, sec, rtc_control;
330
331 if (!is_valid_irq(cmos->irq))
332 return -EIO;
333
334 mon = t->time.tm_mon + 1;
335 mday = t->time.tm_mday;
336 hrs = t->time.tm_hour;
337 min = t->time.tm_min;
338 sec = t->time.tm_sec;
339
340 rtc_control = CMOS_READ(RTC_CONTROL);
341 if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
342 /* Writing 0xff means "don't care" or "match all". */
343 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
344 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
345 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
346 min = (min < 60) ? bin2bcd(min) : 0xff;
347 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
348 }
349
350 spin_lock_irq(&rtc_lock);
351
352 /* next rtc irq must not be from previous alarm setting */
353 cmos_irq_disable(cmos, RTC_AIE);
354
355 /* update alarm */
356 CMOS_WRITE(hrs, RTC_HOURS_ALARM);
357 CMOS_WRITE(min, RTC_MINUTES_ALARM);
358 CMOS_WRITE(sec, RTC_SECONDS_ALARM);
359
360 /* the system may support an "enhanced" alarm */
361 if (cmos->day_alrm) {
362 CMOS_WRITE(mday, cmos->day_alrm);
363 if (cmos->mon_alrm)
364 CMOS_WRITE(mon, cmos->mon_alrm);
365 }
366
367 /* FIXME the HPET alarm glue currently ignores day_alrm
368 * and mon_alrm ...
369 */
370 hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
371
372 if (t->enabled)
373 cmos_irq_enable(cmos, RTC_AIE);
374
375 spin_unlock_irq(&rtc_lock);
376
377 return 0;
378}
379
380/*
381 * Do not disable RTC alarm on shutdown - workaround for b0rked BIOSes.
382 */
383static bool alarm_disable_quirk;
384
385static int __init set_alarm_disable_quirk(const struct dmi_system_id *id)
386{
387 alarm_disable_quirk = true;
388 pr_info("rtc-cmos: BIOS has alarm-disable quirk. ");
389 pr_info("RTC alarms disabled\n");
390 return 0;
391}
392
393static const struct dmi_system_id rtc_quirks[] __initconst = {
394 /* https://bugzilla.novell.com/show_bug.cgi?id=805740 */
395 {
396 .callback = set_alarm_disable_quirk,
397 .ident = "IBM Truman",
398 .matches = {
399 DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
400 DMI_MATCH(DMI_PRODUCT_NAME, "4852570"),
401 },
402 },
403 /* https://bugzilla.novell.com/show_bug.cgi?id=812592 */
404 {
405 .callback = set_alarm_disable_quirk,
406 .ident = "Gigabyte GA-990XA-UD3",
407 .matches = {
408 DMI_MATCH(DMI_SYS_VENDOR,
409 "Gigabyte Technology Co., Ltd."),
410 DMI_MATCH(DMI_PRODUCT_NAME, "GA-990XA-UD3"),
411 },
412 },
413 /* http://permalink.gmane.org/gmane.linux.kernel/1604474 */
414 {
415 .callback = set_alarm_disable_quirk,
416 .ident = "Toshiba Satellite L300",
417 .matches = {
418 DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
419 DMI_MATCH(DMI_PRODUCT_NAME, "Satellite L300"),
420 },
421 },
422 {}
423};
424
425static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
426{
427 struct cmos_rtc *cmos = dev_get_drvdata(dev);
428 unsigned long flags;
429
430 if (!is_valid_irq(cmos->irq))
431 return -EINVAL;
432
433 if (alarm_disable_quirk)
434 return 0;
435
436 spin_lock_irqsave(&rtc_lock, flags);
437
438 if (enabled)
439 cmos_irq_enable(cmos, RTC_AIE);
440 else
441 cmos_irq_disable(cmos, RTC_AIE);
442
443 spin_unlock_irqrestore(&rtc_lock, flags);
444 return 0;
445}
446
447#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
448
449static int cmos_procfs(struct device *dev, struct seq_file *seq)
450{
451 struct cmos_rtc *cmos = dev_get_drvdata(dev);
452 unsigned char rtc_control, valid;
453
454 spin_lock_irq(&rtc_lock);
455 rtc_control = CMOS_READ(RTC_CONTROL);
456 valid = CMOS_READ(RTC_VALID);
457 spin_unlock_irq(&rtc_lock);
458
459 /* NOTE: at least ICH6 reports battery status using a different
460 * (non-RTC) bit; and SQWE is ignored on many current systems.
461 */
462 return seq_printf(seq,
463 "periodic_IRQ\t: %s\n"
464 "update_IRQ\t: %s\n"
465 "HPET_emulated\t: %s\n"
466 // "square_wave\t: %s\n"
467 "BCD\t\t: %s\n"
468 "DST_enable\t: %s\n"
469 "periodic_freq\t: %d\n"
470 "batt_status\t: %s\n",
471 (rtc_control & RTC_PIE) ? "yes" : "no",
472 (rtc_control & RTC_UIE) ? "yes" : "no",
473 is_hpet_enabled() ? "yes" : "no",
474 // (rtc_control & RTC_SQWE) ? "yes" : "no",
475 (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
476 (rtc_control & RTC_DST_EN) ? "yes" : "no",
477 cmos->rtc->irq_freq,
478 (valid & RTC_VRT) ? "okay" : "dead");
479}
480
481#else
482#define cmos_procfs NULL
483#endif
484
485static const struct rtc_class_ops cmos_rtc_ops = {
486 .read_time = cmos_read_time,
487 .set_time = cmos_set_time,
488 .read_alarm = cmos_read_alarm,
489 .set_alarm = cmos_set_alarm,
490 .proc = cmos_procfs,
491 .alarm_irq_enable = cmos_alarm_irq_enable,
492};
493
494/*----------------------------------------------------------------*/
495
496/*
497 * All these chips have at least 64 bytes of address space, shared by
498 * RTC registers and NVRAM. Most of those bytes of NVRAM are used
499 * by boot firmware. Modern chips have 128 or 256 bytes.
500 */
501
502#define NVRAM_OFFSET (RTC_REG_D + 1)
503
504static ssize_t
505cmos_nvram_read(struct file *filp, struct kobject *kobj,
506 struct bin_attribute *attr,
507 char *buf, loff_t off, size_t count)
508{
509 int retval;
510
511 if (unlikely(off >= attr->size))
512 return 0;
513 if (unlikely(off < 0))
514 return -EINVAL;
515 if ((off + count) > attr->size)
516 count = attr->size - off;
517
518 off += NVRAM_OFFSET;
519 spin_lock_irq(&rtc_lock);
520 for (retval = 0; count; count--, off++, retval++) {
521 if (off < 128)
522 *buf++ = CMOS_READ(off);
523 else if (can_bank2)
524 *buf++ = cmos_read_bank2(off);
525 else
526 break;
527 }
528 spin_unlock_irq(&rtc_lock);
529
530 return retval;
531}
532
533static ssize_t
534cmos_nvram_write(struct file *filp, struct kobject *kobj,
535 struct bin_attribute *attr,
536 char *buf, loff_t off, size_t count)
537{
538 struct cmos_rtc *cmos;
539 int retval;
540
541 cmos = dev_get_drvdata(container_of(kobj, struct device, kobj));
542 if (unlikely(off >= attr->size))
543 return -EFBIG;
544 if (unlikely(off < 0))
545 return -EINVAL;
546 if ((off + count) > attr->size)
547 count = attr->size - off;
548
549 /* NOTE: on at least PCs and Ataris, the boot firmware uses a
550 * checksum on part of the NVRAM data. That's currently ignored
551 * here. If userspace is smart enough to know what fields of
552 * NVRAM to update, updating checksums is also part of its job.
553 */
554 off += NVRAM_OFFSET;
555 spin_lock_irq(&rtc_lock);
556 for (retval = 0; count; count--, off++, retval++) {
557 /* don't trash RTC registers */
558 if (off == cmos->day_alrm
559 || off == cmos->mon_alrm
560 || off == cmos->century)
561 buf++;
562 else if (off < 128)
563 CMOS_WRITE(*buf++, off);
564 else if (can_bank2)
565 cmos_write_bank2(*buf++, off);
566 else
567 break;
568 }
569 spin_unlock_irq(&rtc_lock);
570
571 return retval;
572}
573
574static struct bin_attribute nvram = {
575 .attr = {
576 .name = "nvram",
577 .mode = S_IRUGO | S_IWUSR,
578 },
579
580 .read = cmos_nvram_read,
581 .write = cmos_nvram_write,
582 /* size gets set up later */
583};
584
585/*----------------------------------------------------------------*/
586
587static struct cmos_rtc cmos_rtc;
588
589static irqreturn_t cmos_interrupt(int irq, void *p)
590{
591 u8 irqstat;
592 u8 rtc_control;
593
594 spin_lock(&rtc_lock);
595
596 /* When the HPET interrupt handler calls us, the interrupt
597 * status is passed as arg1 instead of the irq number. But
598 * always clear irq status, even when HPET is in the way.
599 *
600 * Note that HPET and RTC are almost certainly out of phase,
601 * giving different IRQ status ...
602 */
603 irqstat = CMOS_READ(RTC_INTR_FLAGS);
604 rtc_control = CMOS_READ(RTC_CONTROL);
605 if (is_hpet_enabled())
606 irqstat = (unsigned long)irq & 0xF0;
607
608 /* If we were suspended, RTC_CONTROL may not be accurate since the
609 * bios may have cleared it.
610 */
611 if (!cmos_rtc.suspend_ctrl)
612 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
613 else
614 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
615
616 /* All Linux RTC alarms should be treated as if they were oneshot.
617 * Similar code may be needed in system wakeup paths, in case the
618 * alarm woke the system.
619 */
620 if (irqstat & RTC_AIE) {
621 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
622 rtc_control &= ~RTC_AIE;
623 CMOS_WRITE(rtc_control, RTC_CONTROL);
624 hpet_mask_rtc_irq_bit(RTC_AIE);
625 CMOS_READ(RTC_INTR_FLAGS);
626 }
627 spin_unlock(&rtc_lock);
628
629 if (is_intr(irqstat)) {
630 rtc_update_irq(p, 1, irqstat);
631 return IRQ_HANDLED;
632 } else
633 return IRQ_NONE;
634}
635
636#ifdef CONFIG_PNP
637#define INITSECTION
638
639#else
640#define INITSECTION __init
641#endif
642
643static int INITSECTION
644cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
645{
646 struct cmos_rtc_board_info *info = dev_get_platdata(dev);
647 int retval = 0;
648 unsigned char rtc_control;
649 unsigned address_space;
650
651 /* there can be only one ... */
652 if (cmos_rtc.dev)
653 return -EBUSY;
654
655 if (!ports)
656 return -ENODEV;
657
658 /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
659 *
660 * REVISIT non-x86 systems may instead use memory space resources
661 * (needing ioremap etc), not i/o space resources like this ...
662 */
663 ports = request_region(ports->start,
664 resource_size(ports),
665 driver_name);
666 if (!ports) {
667 dev_dbg(dev, "i/o registers already in use\n");
668 return -EBUSY;
669 }
670
671 cmos_rtc.irq = rtc_irq;
672 cmos_rtc.iomem = ports;
673
674 /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
675 * driver did, but don't reject unknown configs. Old hardware
676 * won't address 128 bytes. Newer chips have multiple banks,
677 * though they may not be listed in one I/O resource.
678 */
679#if defined(CONFIG_ATARI)
680 address_space = 64;
681#elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
682 || defined(__sparc__) || defined(__mips__) \
683 || defined(__powerpc__)
684 address_space = 128;
685#else
686#warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
687 address_space = 128;
688#endif
689 if (can_bank2 && ports->end > (ports->start + 1))
690 address_space = 256;
691
692 /* For ACPI systems extension info comes from the FADT. On others,
693 * board specific setup provides it as appropriate. Systems where
694 * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
695 * some almost-clones) can provide hooks to make that behave.
696 *
697 * Note that ACPI doesn't preclude putting these registers into
698 * "extended" areas of the chip, including some that we won't yet
699 * expect CMOS_READ and friends to handle.
700 */
701 if (info) {
702 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
703 cmos_rtc.day_alrm = info->rtc_day_alarm;
704 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
705 cmos_rtc.mon_alrm = info->rtc_mon_alarm;
706 if (info->rtc_century && info->rtc_century < 128)
707 cmos_rtc.century = info->rtc_century;
708
709 if (info->wake_on && info->wake_off) {
710 cmos_rtc.wake_on = info->wake_on;
711 cmos_rtc.wake_off = info->wake_off;
712 }
713 }
714
715 cmos_rtc.dev = dev;
716 dev_set_drvdata(dev, &cmos_rtc);
717
718 cmos_rtc.rtc = rtc_device_register(driver_name, dev,
719 &cmos_rtc_ops, THIS_MODULE);
720 if (IS_ERR(cmos_rtc.rtc)) {
721 retval = PTR_ERR(cmos_rtc.rtc);
722 goto cleanup0;
723 }
724
725 rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
726
727 spin_lock_irq(&rtc_lock);
728
729 /* force periodic irq to CMOS reset default of 1024Hz;
730 *
731 * REVISIT it's been reported that at least one x86_64 ALI mobo
732 * doesn't use 32KHz here ... for portability we might need to
733 * do something about other clock frequencies.
734 */
735 cmos_rtc.rtc->irq_freq = 1024;
736 hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
737 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
738
739 /* disable irqs */
740 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
741
742 rtc_control = CMOS_READ(RTC_CONTROL);
743
744 spin_unlock_irq(&rtc_lock);
745
746 /* FIXME:
747 * <asm-generic/rtc.h> doesn't know 12-hour mode either.
748 */
749 if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
750 dev_warn(dev, "only 24-hr supported\n");
751 retval = -ENXIO;
752 goto cleanup1;
753 }
754
755 if (is_valid_irq(rtc_irq)) {
756 irq_handler_t rtc_cmos_int_handler;
757
758 if (is_hpet_enabled()) {
759 rtc_cmos_int_handler = hpet_rtc_interrupt;
760 retval = hpet_register_irq_handler(cmos_interrupt);
761 if (retval) {
762 dev_warn(dev, "hpet_register_irq_handler "
763 " failed in rtc_init().");
764 goto cleanup1;
765 }
766 } else
767 rtc_cmos_int_handler = cmos_interrupt;
768
769 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
770 0, dev_name(&cmos_rtc.rtc->dev),
771 cmos_rtc.rtc);
772 if (retval < 0) {
773 dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
774 goto cleanup1;
775 }
776 }
777 hpet_rtc_timer_init();
778
779 /* export at least the first block of NVRAM */
780 nvram.size = address_space - NVRAM_OFFSET;
781 retval = sysfs_create_bin_file(&dev->kobj, &nvram);
782 if (retval < 0) {
783 dev_dbg(dev, "can't create nvram file? %d\n", retval);
784 goto cleanup2;
785 }
786
787 dev_info(dev, "%s%s, %zd bytes nvram%s\n",
788 !is_valid_irq(rtc_irq) ? "no alarms" :
789 cmos_rtc.mon_alrm ? "alarms up to one year" :
790 cmos_rtc.day_alrm ? "alarms up to one month" :
791 "alarms up to one day",
792 cmos_rtc.century ? ", y3k" : "",
793 nvram.size,
794 is_hpet_enabled() ? ", hpet irqs" : "");
795
796 return 0;
797
798cleanup2:
799 if (is_valid_irq(rtc_irq))
800 free_irq(rtc_irq, cmos_rtc.rtc);
801cleanup1:
802 cmos_rtc.dev = NULL;
803 rtc_device_unregister(cmos_rtc.rtc);
804cleanup0:
805 release_region(ports->start, resource_size(ports));
806 return retval;
807}
808
809static void cmos_do_shutdown(void)
810{
811 spin_lock_irq(&rtc_lock);
812 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
813 spin_unlock_irq(&rtc_lock);
814}
815
816static void __exit cmos_do_remove(struct device *dev)
817{
818 struct cmos_rtc *cmos = dev_get_drvdata(dev);
819 struct resource *ports;
820
821 cmos_do_shutdown();
822
823 sysfs_remove_bin_file(&dev->kobj, &nvram);
824
825 if (is_valid_irq(cmos->irq)) {
826 free_irq(cmos->irq, cmos->rtc);
827 hpet_unregister_irq_handler(cmos_interrupt);
828 }
829
830 rtc_device_unregister(cmos->rtc);
831 cmos->rtc = NULL;
832
833 ports = cmos->iomem;
834 release_region(ports->start, resource_size(ports));
835 cmos->iomem = NULL;
836
837 cmos->dev = NULL;
838}
839
840#ifdef CONFIG_PM_SLEEP
841
842static int cmos_suspend(struct device *dev)
843{
844 struct cmos_rtc *cmos = dev_get_drvdata(dev);
845 unsigned char tmp;
846
847 /* only the alarm might be a wakeup event source */
848 spin_lock_irq(&rtc_lock);
849 cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
850 if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
851 unsigned char mask;
852
853 if (device_may_wakeup(dev))
854 mask = RTC_IRQMASK & ~RTC_AIE;
855 else
856 mask = RTC_IRQMASK;
857 tmp &= ~mask;
858 CMOS_WRITE(tmp, RTC_CONTROL);
859 hpet_mask_rtc_irq_bit(mask);
860
861 cmos_checkintr(cmos, tmp);
862 }
863 spin_unlock_irq(&rtc_lock);
864
865 if (tmp & RTC_AIE) {
866 cmos->enabled_wake = 1;
867 if (cmos->wake_on)
868 cmos->wake_on(dev);
869 else
870 enable_irq_wake(cmos->irq);
871 }
872
873 dev_dbg(dev, "suspend%s, ctrl %02x\n",
874 (tmp & RTC_AIE) ? ", alarm may wake" : "",
875 tmp);
876
877 return 0;
878}
879
880/* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
881 * after a detour through G3 "mechanical off", although the ACPI spec
882 * says wakeup should only work from G1/S4 "hibernate". To most users,
883 * distinctions between S4 and S5 are pointless. So when the hardware
884 * allows, don't draw that distinction.
885 */
886static inline int cmos_poweroff(struct device *dev)
887{
888 return cmos_suspend(dev);
889}
890
891static int cmos_resume(struct device *dev)
892{
893 struct cmos_rtc *cmos = dev_get_drvdata(dev);
894 unsigned char tmp;
895
896 if (cmos->enabled_wake) {
897 if (cmos->wake_off)
898 cmos->wake_off(dev);
899 else
900 disable_irq_wake(cmos->irq);
901 cmos->enabled_wake = 0;
902 }
903
904 spin_lock_irq(&rtc_lock);
905 tmp = cmos->suspend_ctrl;
906 cmos->suspend_ctrl = 0;
907 /* re-enable any irqs previously active */
908 if (tmp & RTC_IRQMASK) {
909 unsigned char mask;
910
911 if (device_may_wakeup(dev))
912 hpet_rtc_timer_init();
913
914 do {
915 CMOS_WRITE(tmp, RTC_CONTROL);
916 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
917
918 mask = CMOS_READ(RTC_INTR_FLAGS);
919 mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
920 if (!is_hpet_enabled() || !is_intr(mask))
921 break;
922
923 /* force one-shot behavior if HPET blocked
924 * the wake alarm's irq
925 */
926 rtc_update_irq(cmos->rtc, 1, mask);
927 tmp &= ~RTC_AIE;
928 hpet_mask_rtc_irq_bit(RTC_AIE);
929 } while (mask & RTC_AIE);
930 }
931 spin_unlock_irq(&rtc_lock);
932
933 dev_dbg(dev, "resume, ctrl %02x\n", tmp);
934
935 return 0;
936}
937
938#else
939
940static inline int cmos_poweroff(struct device *dev)
941{
942 return -ENOSYS;
943}
944
945#endif
946
947static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
948
949/*----------------------------------------------------------------*/
950
951/* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
952 * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
953 * probably list them in similar PNPBIOS tables; so PNP is more common.
954 *
955 * We don't use legacy "poke at the hardware" probing. Ancient PCs that
956 * predate even PNPBIOS should set up platform_bus devices.
957 */
958
959#ifdef CONFIG_ACPI
960
961#include <linux/acpi.h>
962
963static u32 rtc_handler(void *context)
964{
965 struct device *dev = context;
966
967 pm_wakeup_event(dev, 0);
968 acpi_clear_event(ACPI_EVENT_RTC);
969 acpi_disable_event(ACPI_EVENT_RTC, 0);
970 return ACPI_INTERRUPT_HANDLED;
971}
972
973static inline void rtc_wake_setup(struct device *dev)
974{
975 acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
976 /*
977 * After the RTC handler is installed, the Fixed_RTC event should
978 * be disabled. Only when the RTC alarm is set will it be enabled.
979 */
980 acpi_clear_event(ACPI_EVENT_RTC);
981 acpi_disable_event(ACPI_EVENT_RTC, 0);
982}
983
984static void rtc_wake_on(struct device *dev)
985{
986 acpi_clear_event(ACPI_EVENT_RTC);
987 acpi_enable_event(ACPI_EVENT_RTC, 0);
988}
989
990static void rtc_wake_off(struct device *dev)
991{
992 acpi_disable_event(ACPI_EVENT_RTC, 0);
993}
994
995/* Every ACPI platform has a mc146818 compatible "cmos rtc". Here we find
996 * its device node and pass extra config data. This helps its driver use
997 * capabilities that the now-obsolete mc146818 didn't have, and informs it
998 * that this board's RTC is wakeup-capable (per ACPI spec).
999 */
1000static struct cmos_rtc_board_info acpi_rtc_info;
1001
1002static void cmos_wake_setup(struct device *dev)
1003{
1004 if (acpi_disabled)
1005 return;
1006
1007 rtc_wake_setup(dev);
1008 acpi_rtc_info.wake_on = rtc_wake_on;
1009 acpi_rtc_info.wake_off = rtc_wake_off;
1010
1011 /* workaround bug in some ACPI tables */
1012 if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1013 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1014 acpi_gbl_FADT.month_alarm);
1015 acpi_gbl_FADT.month_alarm = 0;
1016 }
1017
1018 acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1019 acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1020 acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1021
1022 /* NOTE: S4_RTC_WAKE is NOT currently useful to Linux */
1023 if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1024 dev_info(dev, "RTC can wake from S4\n");
1025
1026 dev->platform_data = &acpi_rtc_info;
1027
1028 /* RTC always wakes from S1/S2/S3, and often S4/STD */
1029 device_init_wakeup(dev, 1);
1030}
1031
1032#else
1033
1034static void cmos_wake_setup(struct device *dev)
1035{
1036}
1037
1038#endif
1039
1040#ifdef CONFIG_PNP
1041
1042#include <linux/pnp.h>
1043
1044static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1045{
1046 cmos_wake_setup(&pnp->dev);
1047
1048 if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0))
1049 /* Some machines contain a PNP entry for the RTC, but
1050 * don't define the IRQ. It should always be safe to
1051 * hardcode it in these cases
1052 */
1053 return cmos_do_probe(&pnp->dev,
1054 pnp_get_resource(pnp, IORESOURCE_IO, 0), 8);
1055 else
1056 return cmos_do_probe(&pnp->dev,
1057 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1058 pnp_irq(pnp, 0));
1059}
1060
1061static void __exit cmos_pnp_remove(struct pnp_dev *pnp)
1062{
1063 cmos_do_remove(&pnp->dev);
1064}
1065
1066static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1067{
1068 if (system_state == SYSTEM_POWER_OFF && !cmos_poweroff(&pnp->dev))
1069 return;
1070
1071 cmos_do_shutdown();
1072}
1073
1074static const struct pnp_device_id rtc_ids[] = {
1075 { .id = "PNP0b00", },
1076 { .id = "PNP0b01", },
1077 { .id = "PNP0b02", },
1078 { },
1079};
1080MODULE_DEVICE_TABLE(pnp, rtc_ids);
1081
1082static struct pnp_driver cmos_pnp_driver = {
1083 .name = (char *) driver_name,
1084 .id_table = rtc_ids,
1085 .probe = cmos_pnp_probe,
1086 .remove = __exit_p(cmos_pnp_remove),
1087 .shutdown = cmos_pnp_shutdown,
1088
1089 /* flag ensures resume() gets called, and stops syslog spam */
1090 .flags = PNP_DRIVER_RES_DO_NOT_CHANGE,
1091 .driver = {
1092 .pm = &cmos_pm_ops,
1093 },
1094};
1095
1096#endif /* CONFIG_PNP */
1097
1098#ifdef CONFIG_OF
1099static const struct of_device_id of_cmos_match[] = {
1100 {
1101 .compatible = "motorola,mc146818",
1102 },
1103 { },
1104};
1105MODULE_DEVICE_TABLE(of, of_cmos_match);
1106
1107static __init void cmos_of_init(struct platform_device *pdev)
1108{
1109 struct device_node *node = pdev->dev.of_node;
1110 struct rtc_time time;
1111 int ret;
1112 const __be32 *val;
1113
1114 if (!node)
1115 return;
1116
1117 val = of_get_property(node, "ctrl-reg", NULL);
1118 if (val)
1119 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1120
1121 val = of_get_property(node, "freq-reg", NULL);
1122 if (val)
1123 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1124
1125 get_rtc_time(&time);
1126 ret = rtc_valid_tm(&time);
1127 if (ret) {
1128 struct rtc_time def_time = {
1129 .tm_year = 1,
1130 .tm_mday = 1,
1131 };
1132 set_rtc_time(&def_time);
1133 }
1134}
1135#else
1136static inline void cmos_of_init(struct platform_device *pdev) {}
1137#endif
1138/*----------------------------------------------------------------*/
1139
1140/* Platform setup should have set up an RTC device, when PNP is
1141 * unavailable ... this could happen even on (older) PCs.
1142 */
1143
1144static int __init cmos_platform_probe(struct platform_device *pdev)
1145{
1146 cmos_of_init(pdev);
1147 cmos_wake_setup(&pdev->dev);
1148 return cmos_do_probe(&pdev->dev,
1149 platform_get_resource(pdev, IORESOURCE_IO, 0),
1150 platform_get_irq(pdev, 0));
1151}
1152
1153static int __exit cmos_platform_remove(struct platform_device *pdev)
1154{
1155 cmos_do_remove(&pdev->dev);
1156 return 0;
1157}
1158
1159static void cmos_platform_shutdown(struct platform_device *pdev)
1160{
1161 if (system_state == SYSTEM_POWER_OFF && !cmos_poweroff(&pdev->dev))
1162 return;
1163
1164 cmos_do_shutdown();
1165}
1166
1167/* work with hotplug and coldplug */
1168MODULE_ALIAS("platform:rtc_cmos");
1169
1170static struct platform_driver cmos_platform_driver = {
1171 .remove = __exit_p(cmos_platform_remove),
1172 .shutdown = cmos_platform_shutdown,
1173 .driver = {
1174 .name = driver_name,
1175#ifdef CONFIG_PM
1176 .pm = &cmos_pm_ops,
1177#endif
1178 .of_match_table = of_match_ptr(of_cmos_match),
1179 }
1180};
1181
1182#ifdef CONFIG_PNP
1183static bool pnp_driver_registered;
1184#endif
1185static bool platform_driver_registered;
1186
1187static int __init cmos_init(void)
1188{
1189 int retval = 0;
1190
1191#ifdef CONFIG_PNP
1192 retval = pnp_register_driver(&cmos_pnp_driver);
1193 if (retval == 0)
1194 pnp_driver_registered = true;
1195#endif
1196
1197 if (!cmos_rtc.dev) {
1198 retval = platform_driver_probe(&cmos_platform_driver,
1199 cmos_platform_probe);
1200 if (retval == 0)
1201 platform_driver_registered = true;
1202 }
1203
1204 dmi_check_system(rtc_quirks);
1205
1206 if (retval == 0)
1207 return 0;
1208
1209#ifdef CONFIG_PNP
1210 if (pnp_driver_registered)
1211 pnp_unregister_driver(&cmos_pnp_driver);
1212#endif
1213 return retval;
1214}
1215module_init(cmos_init);
1216
1217static void __exit cmos_exit(void)
1218{
1219#ifdef CONFIG_PNP
1220 if (pnp_driver_registered)
1221 pnp_unregister_driver(&cmos_pnp_driver);
1222#endif
1223 if (platform_driver_registered)
1224 platform_driver_unregister(&cmos_platform_driver);
1225}
1226module_exit(cmos_exit);
1227
1228
1229MODULE_AUTHOR("David Brownell");
1230MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1231MODULE_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");