2 * RTC class driver for "CMOS RTC": PCs, ACPI, etc
4 * Copyright (C) 1996 Paul Gortmaker (drivers/char/rtc.c)
5 * Copyright (C) 2006 David Brownell (convert to new framework)
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.
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.
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).
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.
32 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
43 #include <linux/of_platform.h>
45 #include <asm/i8259.h>
46 #include <asm/processor.h>
47 #include <linux/dmi.h>
50 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
51 #include <linux/mc146818rtc.h>
55 * Use ACPI SCI to replace HPET interrupt for RTC Alarm event
57 * If cleared, ACPI SCI is only used to wake up the system from suspend
59 * If set, ACPI SCI is used to handle UIE/AIE and system wakeup
62 static bool use_acpi_alarm;
63 module_param(use_acpi_alarm, bool, 0444);
65 static inline int cmos_use_acpi_alarm(void)
67 return use_acpi_alarm;
69 #else /* !CONFIG_ACPI */
71 static inline int cmos_use_acpi_alarm(void)
78 struct rtc_device *rtc;
81 struct resource *iomem;
82 time64_t alarm_expires;
84 void (*wake_on)(struct device *);
85 void (*wake_off)(struct device *);
90 /* newer hardware extends the original register set */
95 struct rtc_wkalrm saved_wkalrm;
98 /* both platform and pnp busses use negative numbers for invalid irqs */
99 #define is_valid_irq(n) ((n) > 0)
101 static const char driver_name[] = "rtc_cmos";
103 /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
104 * always mask it against the irq enable bits in RTC_CONTROL. Bit values
105 * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
107 #define RTC_IRQMASK (RTC_PF | RTC_AF | RTC_UF)
109 static inline int is_intr(u8 rtc_intr)
111 if (!(rtc_intr & RTC_IRQF))
113 return rtc_intr & RTC_IRQMASK;
116 /*----------------------------------------------------------------*/
118 /* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
119 * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
120 * used in a broken "legacy replacement" mode. The breakage includes
121 * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
122 * other (better) use.
124 * When that broken mode is in use, platform glue provides a partial
125 * emulation of hardware RTC IRQ facilities using HPET #1. We don't
126 * want to use HPET for anything except those IRQs though...
128 #ifdef CONFIG_HPET_EMULATE_RTC
129 #include <asm/hpet.h>
132 static inline int is_hpet_enabled(void)
137 static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
142 static inline int hpet_set_rtc_irq_bit(unsigned long mask)
148 hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
153 static inline int hpet_set_periodic_freq(unsigned long freq)
158 static inline int hpet_rtc_dropped_irq(void)
163 static inline int hpet_rtc_timer_init(void)
168 extern irq_handler_t hpet_rtc_interrupt;
170 static inline int hpet_register_irq_handler(irq_handler_t handler)
175 static inline int hpet_unregister_irq_handler(irq_handler_t handler)
182 /* Don't use HPET for RTC Alarm event if ACPI Fixed event is used */
183 static inline int use_hpet_alarm(void)
185 return is_hpet_enabled() && !cmos_use_acpi_alarm();
188 /*----------------------------------------------------------------*/
192 /* Most newer x86 systems have two register banks, the first used
193 * for RTC and NVRAM and the second only for NVRAM. Caller must
194 * own rtc_lock ... and we won't worry about access during NMI.
196 #define can_bank2 true
198 static inline unsigned char cmos_read_bank2(unsigned char addr)
200 outb(addr, RTC_PORT(2));
201 return inb(RTC_PORT(3));
204 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
206 outb(addr, RTC_PORT(2));
207 outb(val, RTC_PORT(3));
212 #define can_bank2 false
214 static inline unsigned char cmos_read_bank2(unsigned char addr)
219 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
225 /*----------------------------------------------------------------*/
227 static int cmos_read_time(struct device *dev, struct rtc_time *t)
230 * If pm_trace abused the RTC for storage, set the timespec to 0,
231 * which tells the caller that this RTC value is unusable.
233 if (!pm_trace_rtc_valid())
236 /* REVISIT: if the clock has a "century" register, use
237 * that instead of the heuristic in mc146818_get_time().
238 * That'll make Y3K compatility (year > 2070) easy!
240 mc146818_get_time(t);
244 static int cmos_set_time(struct device *dev, struct rtc_time *t)
246 /* REVISIT: set the "century" register if available
248 * NOTE: this ignores the issue whereby updating the seconds
249 * takes effect exactly 500ms after we write the register.
250 * (Also queueing and other delays before we get this far.)
252 return mc146818_set_time(t);
255 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
257 struct cmos_rtc *cmos = dev_get_drvdata(dev);
258 unsigned char rtc_control;
260 if (!is_valid_irq(cmos->irq))
263 /* Basic alarms only support hour, minute, and seconds fields.
264 * Some also support day and month, for alarms up to a year in
268 spin_lock_irq(&rtc_lock);
269 t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
270 t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
271 t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
273 if (cmos->day_alrm) {
274 /* ignore upper bits on readback per ACPI spec */
275 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
276 if (!t->time.tm_mday)
277 t->time.tm_mday = -1;
279 if (cmos->mon_alrm) {
280 t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
286 rtc_control = CMOS_READ(RTC_CONTROL);
287 spin_unlock_irq(&rtc_lock);
289 if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
290 if (((unsigned)t->time.tm_sec) < 0x60)
291 t->time.tm_sec = bcd2bin(t->time.tm_sec);
294 if (((unsigned)t->time.tm_min) < 0x60)
295 t->time.tm_min = bcd2bin(t->time.tm_min);
298 if (((unsigned)t->time.tm_hour) < 0x24)
299 t->time.tm_hour = bcd2bin(t->time.tm_hour);
301 t->time.tm_hour = -1;
303 if (cmos->day_alrm) {
304 if (((unsigned)t->time.tm_mday) <= 0x31)
305 t->time.tm_mday = bcd2bin(t->time.tm_mday);
307 t->time.tm_mday = -1;
309 if (cmos->mon_alrm) {
310 if (((unsigned)t->time.tm_mon) <= 0x12)
311 t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
318 t->enabled = !!(rtc_control & RTC_AIE);
324 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
326 unsigned char rtc_intr;
328 /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
329 * allegedly some older rtcs need that to handle irqs properly
331 rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
333 if (use_hpet_alarm())
336 rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
337 if (is_intr(rtc_intr))
338 rtc_update_irq(cmos->rtc, 1, rtc_intr);
341 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
343 unsigned char rtc_control;
345 /* flush any pending IRQ status, notably for update irqs,
346 * before we enable new IRQs
348 rtc_control = CMOS_READ(RTC_CONTROL);
349 cmos_checkintr(cmos, rtc_control);
352 CMOS_WRITE(rtc_control, RTC_CONTROL);
353 if (use_hpet_alarm())
354 hpet_set_rtc_irq_bit(mask);
356 if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
358 cmos->wake_on(cmos->dev);
361 cmos_checkintr(cmos, rtc_control);
364 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
366 unsigned char rtc_control;
368 rtc_control = CMOS_READ(RTC_CONTROL);
369 rtc_control &= ~mask;
370 CMOS_WRITE(rtc_control, RTC_CONTROL);
371 if (use_hpet_alarm())
372 hpet_mask_rtc_irq_bit(mask);
374 if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
376 cmos->wake_off(cmos->dev);
379 cmos_checkintr(cmos, rtc_control);
382 static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t)
384 struct cmos_rtc *cmos = dev_get_drvdata(dev);
387 cmos_read_time(dev, &now);
389 if (!cmos->day_alrm) {
393 t_max_date = rtc_tm_to_time64(&now);
394 t_max_date += 24 * 60 * 60 - 1;
395 t_alrm = rtc_tm_to_time64(&t->time);
396 if (t_alrm > t_max_date) {
398 "Alarms can be up to one day in the future\n");
401 } else if (!cmos->mon_alrm) {
402 struct rtc_time max_date = now;
407 if (max_date.tm_mon == 11) {
409 max_date.tm_year += 1;
411 max_date.tm_mon += 1;
413 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
414 if (max_date.tm_mday > max_mday)
415 max_date.tm_mday = max_mday;
417 t_max_date = rtc_tm_to_time64(&max_date);
419 t_alrm = rtc_tm_to_time64(&t->time);
420 if (t_alrm > t_max_date) {
422 "Alarms can be up to one month in the future\n");
426 struct rtc_time max_date = now;
431 max_date.tm_year += 1;
432 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
433 if (max_date.tm_mday > max_mday)
434 max_date.tm_mday = max_mday;
436 t_max_date = rtc_tm_to_time64(&max_date);
438 t_alrm = rtc_tm_to_time64(&t->time);
439 if (t_alrm > t_max_date) {
441 "Alarms can be up to one year in the future\n");
449 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
451 struct cmos_rtc *cmos = dev_get_drvdata(dev);
452 unsigned char mon, mday, hrs, min, sec, rtc_control;
455 if (!is_valid_irq(cmos->irq))
458 ret = cmos_validate_alarm(dev, t);
462 mon = t->time.tm_mon + 1;
463 mday = t->time.tm_mday;
464 hrs = t->time.tm_hour;
465 min = t->time.tm_min;
466 sec = t->time.tm_sec;
468 rtc_control = CMOS_READ(RTC_CONTROL);
469 if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
470 /* Writing 0xff means "don't care" or "match all". */
471 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
472 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
473 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
474 min = (min < 60) ? bin2bcd(min) : 0xff;
475 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
478 spin_lock_irq(&rtc_lock);
480 /* next rtc irq must not be from previous alarm setting */
481 cmos_irq_disable(cmos, RTC_AIE);
484 CMOS_WRITE(hrs, RTC_HOURS_ALARM);
485 CMOS_WRITE(min, RTC_MINUTES_ALARM);
486 CMOS_WRITE(sec, RTC_SECONDS_ALARM);
488 /* the system may support an "enhanced" alarm */
489 if (cmos->day_alrm) {
490 CMOS_WRITE(mday, cmos->day_alrm);
492 CMOS_WRITE(mon, cmos->mon_alrm);
495 if (use_hpet_alarm()) {
497 * FIXME the HPET alarm glue currently ignores day_alrm
500 hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min,
505 cmos_irq_enable(cmos, RTC_AIE);
507 spin_unlock_irq(&rtc_lock);
509 cmos->alarm_expires = rtc_tm_to_time64(&t->time);
514 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
516 struct cmos_rtc *cmos = dev_get_drvdata(dev);
519 if (!is_valid_irq(cmos->irq))
522 spin_lock_irqsave(&rtc_lock, flags);
525 cmos_irq_enable(cmos, RTC_AIE);
527 cmos_irq_disable(cmos, RTC_AIE);
529 spin_unlock_irqrestore(&rtc_lock, flags);
533 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
535 static int cmos_procfs(struct device *dev, struct seq_file *seq)
537 struct cmos_rtc *cmos = dev_get_drvdata(dev);
538 unsigned char rtc_control, valid;
540 spin_lock_irq(&rtc_lock);
541 rtc_control = CMOS_READ(RTC_CONTROL);
542 valid = CMOS_READ(RTC_VALID);
543 spin_unlock_irq(&rtc_lock);
545 /* NOTE: at least ICH6 reports battery status using a different
546 * (non-RTC) bit; and SQWE is ignored on many current systems.
549 "periodic_IRQ\t: %s\n"
551 "HPET_emulated\t: %s\n"
552 // "square_wave\t: %s\n"
555 "periodic_freq\t: %d\n"
556 "batt_status\t: %s\n",
557 (rtc_control & RTC_PIE) ? "yes" : "no",
558 (rtc_control & RTC_UIE) ? "yes" : "no",
559 use_hpet_alarm() ? "yes" : "no",
560 // (rtc_control & RTC_SQWE) ? "yes" : "no",
561 (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
562 (rtc_control & RTC_DST_EN) ? "yes" : "no",
564 (valid & RTC_VRT) ? "okay" : "dead");
570 #define cmos_procfs NULL
573 static const struct rtc_class_ops cmos_rtc_ops = {
574 .read_time = cmos_read_time,
575 .set_time = cmos_set_time,
576 .read_alarm = cmos_read_alarm,
577 .set_alarm = cmos_set_alarm,
579 .alarm_irq_enable = cmos_alarm_irq_enable,
582 /*----------------------------------------------------------------*/
585 * All these chips have at least 64 bytes of address space, shared by
586 * RTC registers and NVRAM. Most of those bytes of NVRAM are used
587 * by boot firmware. Modern chips have 128 or 256 bytes.
590 #define NVRAM_OFFSET (RTC_REG_D + 1)
592 static int cmos_nvram_read(void *priv, unsigned int off, void *val,
595 unsigned char *buf = val;
599 spin_lock_irq(&rtc_lock);
600 for (retval = 0; count; count--, off++, retval++) {
602 *buf++ = CMOS_READ(off);
604 *buf++ = cmos_read_bank2(off);
608 spin_unlock_irq(&rtc_lock);
613 static int cmos_nvram_write(void *priv, unsigned int off, void *val,
616 struct cmos_rtc *cmos = priv;
617 unsigned char *buf = val;
620 /* NOTE: on at least PCs and Ataris, the boot firmware uses a
621 * checksum on part of the NVRAM data. That's currently ignored
622 * here. If userspace is smart enough to know what fields of
623 * NVRAM to update, updating checksums is also part of its job.
626 spin_lock_irq(&rtc_lock);
627 for (retval = 0; count; count--, off++, retval++) {
628 /* don't trash RTC registers */
629 if (off == cmos->day_alrm
630 || off == cmos->mon_alrm
631 || off == cmos->century)
634 CMOS_WRITE(*buf++, off);
636 cmos_write_bank2(*buf++, off);
640 spin_unlock_irq(&rtc_lock);
645 /*----------------------------------------------------------------*/
647 static struct cmos_rtc cmos_rtc;
649 static irqreturn_t cmos_interrupt(int irq, void *p)
654 spin_lock(&rtc_lock);
656 /* When the HPET interrupt handler calls us, the interrupt
657 * status is passed as arg1 instead of the irq number. But
658 * always clear irq status, even when HPET is in the way.
660 * Note that HPET and RTC are almost certainly out of phase,
661 * giving different IRQ status ...
663 irqstat = CMOS_READ(RTC_INTR_FLAGS);
664 rtc_control = CMOS_READ(RTC_CONTROL);
665 if (use_hpet_alarm())
666 irqstat = (unsigned long)irq & 0xF0;
668 /* If we were suspended, RTC_CONTROL may not be accurate since the
669 * bios may have cleared it.
671 if (!cmos_rtc.suspend_ctrl)
672 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
674 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
676 /* All Linux RTC alarms should be treated as if they were oneshot.
677 * Similar code may be needed in system wakeup paths, in case the
678 * alarm woke the system.
680 if (irqstat & RTC_AIE) {
681 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
682 rtc_control &= ~RTC_AIE;
683 CMOS_WRITE(rtc_control, RTC_CONTROL);
684 if (use_hpet_alarm())
685 hpet_mask_rtc_irq_bit(RTC_AIE);
686 CMOS_READ(RTC_INTR_FLAGS);
688 spin_unlock(&rtc_lock);
690 if (is_intr(irqstat)) {
691 rtc_update_irq(p, 1, irqstat);
701 #define INITSECTION __init
704 static int INITSECTION
705 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
707 struct cmos_rtc_board_info *info = dev_get_platdata(dev);
709 unsigned char rtc_control;
710 unsigned address_space;
712 struct nvmem_config nvmem_cfg = {
713 .name = "cmos_nvram",
716 .reg_read = cmos_nvram_read,
717 .reg_write = cmos_nvram_write,
721 /* there can be only one ... */
728 /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
730 * REVISIT non-x86 systems may instead use memory space resources
731 * (needing ioremap etc), not i/o space resources like this ...
734 ports = request_region(ports->start, resource_size(ports),
737 ports = request_mem_region(ports->start, resource_size(ports),
740 dev_dbg(dev, "i/o registers already in use\n");
744 cmos_rtc.irq = rtc_irq;
745 cmos_rtc.iomem = ports;
747 /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
748 * driver did, but don't reject unknown configs. Old hardware
749 * won't address 128 bytes. Newer chips have multiple banks,
750 * though they may not be listed in one I/O resource.
752 #if defined(CONFIG_ATARI)
754 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
755 || defined(__sparc__) || defined(__mips__) \
756 || defined(__powerpc__)
759 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
762 if (can_bank2 && ports->end > (ports->start + 1))
765 /* For ACPI systems extension info comes from the FADT. On others,
766 * board specific setup provides it as appropriate. Systems where
767 * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
768 * some almost-clones) can provide hooks to make that behave.
770 * Note that ACPI doesn't preclude putting these registers into
771 * "extended" areas of the chip, including some that we won't yet
772 * expect CMOS_READ and friends to handle.
777 if (info->address_space)
778 address_space = info->address_space;
780 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
781 cmos_rtc.day_alrm = info->rtc_day_alarm;
782 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
783 cmos_rtc.mon_alrm = info->rtc_mon_alarm;
784 if (info->rtc_century && info->rtc_century < 128)
785 cmos_rtc.century = info->rtc_century;
787 if (info->wake_on && info->wake_off) {
788 cmos_rtc.wake_on = info->wake_on;
789 cmos_rtc.wake_off = info->wake_off;
794 dev_set_drvdata(dev, &cmos_rtc);
796 cmos_rtc.rtc = devm_rtc_allocate_device(dev);
797 if (IS_ERR(cmos_rtc.rtc)) {
798 retval = PTR_ERR(cmos_rtc.rtc);
802 rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
804 spin_lock_irq(&rtc_lock);
806 if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
807 /* force periodic irq to CMOS reset default of 1024Hz;
809 * REVISIT it's been reported that at least one x86_64 ALI
810 * mobo doesn't use 32KHz here ... for portability we might
811 * need to do something about other clock frequencies.
813 cmos_rtc.rtc->irq_freq = 1024;
814 if (use_hpet_alarm())
815 hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
816 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
820 if (is_valid_irq(rtc_irq))
821 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
823 rtc_control = CMOS_READ(RTC_CONTROL);
825 spin_unlock_irq(&rtc_lock);
827 if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
828 dev_warn(dev, "only 24-hr supported\n");
833 if (use_hpet_alarm())
834 hpet_rtc_timer_init();
836 if (is_valid_irq(rtc_irq)) {
837 irq_handler_t rtc_cmos_int_handler;
839 if (use_hpet_alarm()) {
840 rtc_cmos_int_handler = hpet_rtc_interrupt;
841 retval = hpet_register_irq_handler(cmos_interrupt);
843 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
844 dev_warn(dev, "hpet_register_irq_handler "
845 " failed in rtc_init().");
849 rtc_cmos_int_handler = cmos_interrupt;
851 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
852 IRQF_SHARED, dev_name(&cmos_rtc.rtc->dev),
855 dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
860 cmos_rtc.rtc->ops = &cmos_rtc_ops;
861 cmos_rtc.rtc->nvram_old_abi = true;
862 retval = rtc_register_device(cmos_rtc.rtc);
866 /* export at least the first block of NVRAM */
867 nvmem_cfg.size = address_space - NVRAM_OFFSET;
868 if (rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg))
869 dev_err(dev, "nvmem registration failed\n");
871 dev_info(dev, "%s%s, %d bytes nvram%s\n",
872 !is_valid_irq(rtc_irq) ? "no alarms" :
873 cmos_rtc.mon_alrm ? "alarms up to one year" :
874 cmos_rtc.day_alrm ? "alarms up to one month" :
875 "alarms up to one day",
876 cmos_rtc.century ? ", y3k" : "",
878 use_hpet_alarm() ? ", hpet irqs" : "");
883 if (is_valid_irq(rtc_irq))
884 free_irq(rtc_irq, cmos_rtc.rtc);
889 release_region(ports->start, resource_size(ports));
891 release_mem_region(ports->start, resource_size(ports));
895 static void cmos_do_shutdown(int rtc_irq)
897 spin_lock_irq(&rtc_lock);
898 if (is_valid_irq(rtc_irq))
899 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
900 spin_unlock_irq(&rtc_lock);
903 static void cmos_do_remove(struct device *dev)
905 struct cmos_rtc *cmos = dev_get_drvdata(dev);
906 struct resource *ports;
908 cmos_do_shutdown(cmos->irq);
910 if (is_valid_irq(cmos->irq)) {
911 free_irq(cmos->irq, cmos->rtc);
912 if (use_hpet_alarm())
913 hpet_unregister_irq_handler(cmos_interrupt);
920 release_region(ports->start, resource_size(ports));
922 release_mem_region(ports->start, resource_size(ports));
928 static int cmos_aie_poweroff(struct device *dev)
930 struct cmos_rtc *cmos = dev_get_drvdata(dev);
934 unsigned char rtc_control;
936 if (!cmos->alarm_expires)
939 spin_lock_irq(&rtc_lock);
940 rtc_control = CMOS_READ(RTC_CONTROL);
941 spin_unlock_irq(&rtc_lock);
943 /* We only care about the situation where AIE is disabled. */
944 if (rtc_control & RTC_AIE)
947 cmos_read_time(dev, &now);
948 t_now = rtc_tm_to_time64(&now);
951 * When enabling "RTC wake-up" in BIOS setup, the machine reboots
952 * automatically right after shutdown on some buggy boxes.
953 * This automatic rebooting issue won't happen when the alarm
954 * time is larger than now+1 seconds.
956 * If the alarm time is equal to now+1 seconds, the issue can be
957 * prevented by cancelling the alarm.
959 if (cmos->alarm_expires == t_now + 1) {
960 struct rtc_wkalrm alarm;
962 /* Cancel the AIE timer by configuring the past time. */
963 rtc_time64_to_tm(t_now - 1, &alarm.time);
965 retval = cmos_set_alarm(dev, &alarm);
966 } else if (cmos->alarm_expires > t_now + 1) {
973 static int cmos_suspend(struct device *dev)
975 struct cmos_rtc *cmos = dev_get_drvdata(dev);
978 /* only the alarm might be a wakeup event source */
979 spin_lock_irq(&rtc_lock);
980 cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
981 if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
984 if (device_may_wakeup(dev))
985 mask = RTC_IRQMASK & ~RTC_AIE;
989 CMOS_WRITE(tmp, RTC_CONTROL);
990 if (use_hpet_alarm())
991 hpet_mask_rtc_irq_bit(mask);
992 cmos_checkintr(cmos, tmp);
994 spin_unlock_irq(&rtc_lock);
996 if ((tmp & RTC_AIE) && !cmos_use_acpi_alarm()) {
997 cmos->enabled_wake = 1;
1001 enable_irq_wake(cmos->irq);
1004 cmos_read_alarm(dev, &cmos->saved_wkalrm);
1006 dev_dbg(dev, "suspend%s, ctrl %02x\n",
1007 (tmp & RTC_AIE) ? ", alarm may wake" : "",
1013 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
1014 * after a detour through G3 "mechanical off", although the ACPI spec
1015 * says wakeup should only work from G1/S4 "hibernate". To most users,
1016 * distinctions between S4 and S5 are pointless. So when the hardware
1017 * allows, don't draw that distinction.
1019 static inline int cmos_poweroff(struct device *dev)
1021 if (!IS_ENABLED(CONFIG_PM))
1024 return cmos_suspend(dev);
1027 static void cmos_check_wkalrm(struct device *dev)
1029 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1030 struct rtc_wkalrm current_alarm;
1032 time64_t t_current_expires;
1033 time64_t t_saved_expires;
1034 struct rtc_time now;
1036 /* Check if we have RTC Alarm armed */
1037 if (!(cmos->suspend_ctrl & RTC_AIE))
1040 cmos_read_time(dev, &now);
1041 t_now = rtc_tm_to_time64(&now);
1044 * ACPI RTC wake event is cleared after resume from STR,
1045 * ACK the rtc irq here
1047 if (t_now >= cmos->alarm_expires && cmos_use_acpi_alarm()) {
1048 cmos_interrupt(0, (void *)cmos->rtc);
1052 cmos_read_alarm(dev, ¤t_alarm);
1053 t_current_expires = rtc_tm_to_time64(¤t_alarm.time);
1054 t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
1055 if (t_current_expires != t_saved_expires ||
1056 cmos->saved_wkalrm.enabled != current_alarm.enabled) {
1057 cmos_set_alarm(dev, &cmos->saved_wkalrm);
1061 static void cmos_check_acpi_rtc_status(struct device *dev,
1062 unsigned char *rtc_control);
1064 static int __maybe_unused cmos_resume(struct device *dev)
1066 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1069 if (cmos->enabled_wake && !cmos_use_acpi_alarm()) {
1071 cmos->wake_off(dev);
1073 disable_irq_wake(cmos->irq);
1074 cmos->enabled_wake = 0;
1077 /* The BIOS might have changed the alarm, restore it */
1078 cmos_check_wkalrm(dev);
1080 spin_lock_irq(&rtc_lock);
1081 tmp = cmos->suspend_ctrl;
1082 cmos->suspend_ctrl = 0;
1083 /* re-enable any irqs previously active */
1084 if (tmp & RTC_IRQMASK) {
1087 if (device_may_wakeup(dev) && use_hpet_alarm())
1088 hpet_rtc_timer_init();
1091 CMOS_WRITE(tmp, RTC_CONTROL);
1092 if (use_hpet_alarm())
1093 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1095 mask = CMOS_READ(RTC_INTR_FLAGS);
1096 mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1097 if (!use_hpet_alarm() || !is_intr(mask))
1100 /* force one-shot behavior if HPET blocked
1101 * the wake alarm's irq
1103 rtc_update_irq(cmos->rtc, 1, mask);
1105 hpet_mask_rtc_irq_bit(RTC_AIE);
1106 } while (mask & RTC_AIE);
1109 cmos_check_acpi_rtc_status(dev, &tmp);
1111 spin_unlock_irq(&rtc_lock);
1113 dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1118 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1120 /*----------------------------------------------------------------*/
1122 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1123 * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1124 * probably list them in similar PNPBIOS tables; so PNP is more common.
1126 * We don't use legacy "poke at the hardware" probing. Ancient PCs that
1127 * predate even PNPBIOS should set up platform_bus devices.
1132 #include <linux/acpi.h>
1134 static u32 rtc_handler(void *context)
1136 struct device *dev = context;
1137 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1138 unsigned char rtc_control = 0;
1139 unsigned char rtc_intr;
1140 unsigned long flags;
1144 * Always update rtc irq when ACPI is used as RTC Alarm.
1145 * Or else, ACPI SCI is enabled during suspend/resume only,
1146 * update rtc irq in that case.
1148 if (cmos_use_acpi_alarm())
1149 cmos_interrupt(0, (void *)cmos->rtc);
1151 /* Fix me: can we use cmos_interrupt() here as well? */
1152 spin_lock_irqsave(&rtc_lock, flags);
1153 if (cmos_rtc.suspend_ctrl)
1154 rtc_control = CMOS_READ(RTC_CONTROL);
1155 if (rtc_control & RTC_AIE) {
1156 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1157 CMOS_WRITE(rtc_control, RTC_CONTROL);
1158 rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1159 rtc_update_irq(cmos->rtc, 1, rtc_intr);
1161 spin_unlock_irqrestore(&rtc_lock, flags);
1164 pm_wakeup_hard_event(dev);
1165 acpi_clear_event(ACPI_EVENT_RTC);
1166 acpi_disable_event(ACPI_EVENT_RTC, 0);
1167 return ACPI_INTERRUPT_HANDLED;
1170 static inline void rtc_wake_setup(struct device *dev)
1172 acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1174 * After the RTC handler is installed, the Fixed_RTC event should
1175 * be disabled. Only when the RTC alarm is set will it be enabled.
1177 acpi_clear_event(ACPI_EVENT_RTC);
1178 acpi_disable_event(ACPI_EVENT_RTC, 0);
1181 static void rtc_wake_on(struct device *dev)
1183 acpi_clear_event(ACPI_EVENT_RTC);
1184 acpi_enable_event(ACPI_EVENT_RTC, 0);
1187 static void rtc_wake_off(struct device *dev)
1189 acpi_disable_event(ACPI_EVENT_RTC, 0);
1193 /* Enable use_acpi_alarm mode for Intel platforms no earlier than 2015 */
1194 static void use_acpi_alarm_quirks(void)
1198 if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
1201 if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
1204 if (!is_hpet_enabled())
1207 if (dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL) && year >= 2015)
1208 use_acpi_alarm = true;
1211 static inline void use_acpi_alarm_quirks(void) { }
1214 /* Every ACPI platform has a mc146818 compatible "cmos rtc". Here we find
1215 * its device node and pass extra config data. This helps its driver use
1216 * capabilities that the now-obsolete mc146818 didn't have, and informs it
1217 * that this board's RTC is wakeup-capable (per ACPI spec).
1219 static struct cmos_rtc_board_info acpi_rtc_info;
1221 static void cmos_wake_setup(struct device *dev)
1226 use_acpi_alarm_quirks();
1228 rtc_wake_setup(dev);
1229 acpi_rtc_info.wake_on = rtc_wake_on;
1230 acpi_rtc_info.wake_off = rtc_wake_off;
1232 /* workaround bug in some ACPI tables */
1233 if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1234 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1235 acpi_gbl_FADT.month_alarm);
1236 acpi_gbl_FADT.month_alarm = 0;
1239 acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1240 acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1241 acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1243 /* NOTE: S4_RTC_WAKE is NOT currently useful to Linux */
1244 if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1245 dev_info(dev, "RTC can wake from S4\n");
1247 dev->platform_data = &acpi_rtc_info;
1249 /* RTC always wakes from S1/S2/S3, and often S4/STD */
1250 device_init_wakeup(dev, 1);
1253 static void cmos_check_acpi_rtc_status(struct device *dev,
1254 unsigned char *rtc_control)
1256 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1257 acpi_event_status rtc_status;
1260 if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1263 status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1264 if (ACPI_FAILURE(status)) {
1265 dev_err(dev, "Could not get RTC status\n");
1266 } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1268 *rtc_control &= ~RTC_AIE;
1269 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1270 mask = CMOS_READ(RTC_INTR_FLAGS);
1271 rtc_update_irq(cmos->rtc, 1, mask);
1277 static void cmos_wake_setup(struct device *dev)
1281 static void cmos_check_acpi_rtc_status(struct device *dev,
1282 unsigned char *rtc_control)
1290 #include <linux/pnp.h>
1292 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1294 cmos_wake_setup(&pnp->dev);
1296 if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1297 unsigned int irq = 0;
1299 /* Some machines contain a PNP entry for the RTC, but
1300 * don't define the IRQ. It should always be safe to
1301 * hardcode it on systems with a legacy PIC.
1303 if (nr_legacy_irqs())
1306 return cmos_do_probe(&pnp->dev,
1307 pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1309 return cmos_do_probe(&pnp->dev,
1310 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1315 static void cmos_pnp_remove(struct pnp_dev *pnp)
1317 cmos_do_remove(&pnp->dev);
1320 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1322 struct device *dev = &pnp->dev;
1323 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1325 if (system_state == SYSTEM_POWER_OFF) {
1326 int retval = cmos_poweroff(dev);
1328 if (cmos_aie_poweroff(dev) < 0 && !retval)
1332 cmos_do_shutdown(cmos->irq);
1335 static const struct pnp_device_id rtc_ids[] = {
1336 { .id = "PNP0b00", },
1337 { .id = "PNP0b01", },
1338 { .id = "PNP0b02", },
1341 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1343 static struct pnp_driver cmos_pnp_driver = {
1344 .name = (char *) driver_name,
1345 .id_table = rtc_ids,
1346 .probe = cmos_pnp_probe,
1347 .remove = cmos_pnp_remove,
1348 .shutdown = cmos_pnp_shutdown,
1350 /* flag ensures resume() gets called, and stops syslog spam */
1351 .flags = PNP_DRIVER_RES_DO_NOT_CHANGE,
1357 #endif /* CONFIG_PNP */
1360 static const struct of_device_id of_cmos_match[] = {
1362 .compatible = "motorola,mc146818",
1366 MODULE_DEVICE_TABLE(of, of_cmos_match);
1368 static __init void cmos_of_init(struct platform_device *pdev)
1370 struct device_node *node = pdev->dev.of_node;
1376 val = of_get_property(node, "ctrl-reg", NULL);
1378 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1380 val = of_get_property(node, "freq-reg", NULL);
1382 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1385 static inline void cmos_of_init(struct platform_device *pdev) {}
1387 /*----------------------------------------------------------------*/
1389 /* Platform setup should have set up an RTC device, when PNP is
1390 * unavailable ... this could happen even on (older) PCs.
1393 static int __init cmos_platform_probe(struct platform_device *pdev)
1395 struct resource *resource;
1399 cmos_wake_setup(&pdev->dev);
1402 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1404 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1405 irq = platform_get_irq(pdev, 0);
1409 return cmos_do_probe(&pdev->dev, resource, irq);
1412 static int cmos_platform_remove(struct platform_device *pdev)
1414 cmos_do_remove(&pdev->dev);
1418 static void cmos_platform_shutdown(struct platform_device *pdev)
1420 struct device *dev = &pdev->dev;
1421 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1423 if (system_state == SYSTEM_POWER_OFF) {
1424 int retval = cmos_poweroff(dev);
1426 if (cmos_aie_poweroff(dev) < 0 && !retval)
1430 cmos_do_shutdown(cmos->irq);
1433 /* work with hotplug and coldplug */
1434 MODULE_ALIAS("platform:rtc_cmos");
1436 static struct platform_driver cmos_platform_driver = {
1437 .remove = cmos_platform_remove,
1438 .shutdown = cmos_platform_shutdown,
1440 .name = driver_name,
1442 .of_match_table = of_match_ptr(of_cmos_match),
1447 static bool pnp_driver_registered;
1449 static bool platform_driver_registered;
1451 static int __init cmos_init(void)
1456 retval = pnp_register_driver(&cmos_pnp_driver);
1458 pnp_driver_registered = true;
1461 if (!cmos_rtc.dev) {
1462 retval = platform_driver_probe(&cmos_platform_driver,
1463 cmos_platform_probe);
1465 platform_driver_registered = true;
1472 if (pnp_driver_registered)
1473 pnp_unregister_driver(&cmos_pnp_driver);
1477 module_init(cmos_init);
1479 static void __exit cmos_exit(void)
1482 if (pnp_driver_registered)
1483 pnp_unregister_driver(&cmos_pnp_driver);
1485 if (platform_driver_registered)
1486 platform_driver_unregister(&cmos_platform_driver);
1488 module_exit(cmos_exit);
1491 MODULE_AUTHOR("David Brownell");
1492 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1493 MODULE_LICENSE("GPL");