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.
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>
40 #include <linux/of_platform.h>
41 #include <linux/dmi.h>
43 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
44 #include <asm-generic/rtc.h>
47 struct rtc_device
*rtc
;
50 struct resource
*iomem
;
52 void (*wake_on
)(struct device
*);
53 void (*wake_off
)(struct device
*);
58 /* newer hardware extends the original register set */
64 /* both platform and pnp busses use negative numbers for invalid irqs */
65 #define is_valid_irq(n) ((n) > 0)
67 static const char driver_name
[] = "rtc_cmos";
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.
73 #define RTC_IRQMASK (RTC_PF | RTC_AF | RTC_UF)
75 static inline int is_intr(u8 rtc_intr
)
77 if (!(rtc_intr
& RTC_IRQF
))
79 return rtc_intr
& RTC_IRQMASK
;
82 /*----------------------------------------------------------------*/
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
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...
94 #ifdef CONFIG_HPET_EMULATE_RTC
98 static inline int is_hpet_enabled(void)
103 static inline int hpet_mask_rtc_irq_bit(unsigned long mask
)
108 static inline int hpet_set_rtc_irq_bit(unsigned long mask
)
114 hpet_set_alarm_time(unsigned char hrs
, unsigned char min
, unsigned char sec
)
119 static inline int hpet_set_periodic_freq(unsigned long freq
)
124 static inline int hpet_rtc_dropped_irq(void)
129 static inline int hpet_rtc_timer_init(void)
134 extern irq_handler_t hpet_rtc_interrupt
;
136 static inline int hpet_register_irq_handler(irq_handler_t handler
)
141 static inline int hpet_unregister_irq_handler(irq_handler_t handler
)
148 /*----------------------------------------------------------------*/
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.
156 #define can_bank2 true
158 static inline unsigned char cmos_read_bank2(unsigned char addr
)
160 outb(addr
, RTC_PORT(2));
161 return inb(RTC_PORT(3));
164 static inline void cmos_write_bank2(unsigned char val
, unsigned char addr
)
166 outb(addr
, RTC_PORT(2));
167 outb(val
, RTC_PORT(3));
172 #define can_bank2 false
174 static inline unsigned char cmos_read_bank2(unsigned char addr
)
179 static inline void cmos_write_bank2(unsigned char val
, unsigned char addr
)
185 /*----------------------------------------------------------------*/
187 static int cmos_read_time(struct device
*dev
, struct rtc_time
*t
)
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!
197 static int cmos_set_time(struct device
*dev
, struct rtc_time
*t
)
199 /* REVISIT: set the "century" register if available
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.)
205 return set_rtc_time(t
);
208 static int cmos_read_alarm(struct device
*dev
, struct rtc_wkalrm
*t
)
210 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
211 unsigned char rtc_control
;
213 if (!is_valid_irq(cmos
->irq
))
216 /* Basic alarms only support hour, minute, and seconds fields.
217 * Some also support day and month, for alarms up to a year in
220 t
->time
.tm_mday
= -1;
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
);
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;
234 if (cmos
->mon_alrm
) {
235 t
->time
.tm_mon
= CMOS_READ(cmos
->mon_alrm
);
241 rtc_control
= CMOS_READ(RTC_CONTROL
);
242 spin_unlock_irq(&rtc_lock
);
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
);
249 if (((unsigned)t
->time
.tm_min
) < 0x60)
250 t
->time
.tm_min
= bcd2bin(t
->time
.tm_min
);
253 if (((unsigned)t
->time
.tm_hour
) < 0x24)
254 t
->time
.tm_hour
= bcd2bin(t
->time
.tm_hour
);
256 t
->time
.tm_hour
= -1;
258 if (cmos
->day_alrm
) {
259 if (((unsigned)t
->time
.tm_mday
) <= 0x31)
260 t
->time
.tm_mday
= bcd2bin(t
->time
.tm_mday
);
262 t
->time
.tm_mday
= -1;
264 if (cmos
->mon_alrm
) {
265 if (((unsigned)t
->time
.tm_mon
) <= 0x12)
266 t
->time
.tm_mon
= bcd2bin(t
->time
.tm_mon
)-1;
272 t
->time
.tm_year
= -1;
274 t
->enabled
= !!(rtc_control
& RTC_AIE
);
280 static void cmos_checkintr(struct cmos_rtc
*cmos
, unsigned char rtc_control
)
282 unsigned char rtc_intr
;
284 /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
285 * allegedly some older rtcs need that to handle irqs properly
287 rtc_intr
= CMOS_READ(RTC_INTR_FLAGS
);
289 if (is_hpet_enabled())
292 rtc_intr
&= (rtc_control
& RTC_IRQMASK
) | RTC_IRQF
;
293 if (is_intr(rtc_intr
))
294 rtc_update_irq(cmos
->rtc
, 1, rtc_intr
);
297 static void cmos_irq_enable(struct cmos_rtc
*cmos
, unsigned char mask
)
299 unsigned char rtc_control
;
301 /* flush any pending IRQ status, notably for update irqs,
302 * before we enable new IRQs
304 rtc_control
= CMOS_READ(RTC_CONTROL
);
305 cmos_checkintr(cmos
, rtc_control
);
308 CMOS_WRITE(rtc_control
, RTC_CONTROL
);
309 hpet_set_rtc_irq_bit(mask
);
311 cmos_checkintr(cmos
, rtc_control
);
314 static void cmos_irq_disable(struct cmos_rtc
*cmos
, unsigned char mask
)
316 unsigned char rtc_control
;
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
);
323 cmos_checkintr(cmos
, rtc_control
);
326 static int cmos_set_alarm(struct device
*dev
, struct rtc_wkalrm
*t
)
328 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
329 unsigned char mon
, mday
, hrs
, min
, sec
, rtc_control
;
331 if (!is_valid_irq(cmos
->irq
))
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
;
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;
350 spin_lock_irq(&rtc_lock
);
352 /* next rtc irq must not be from previous alarm setting */
353 cmos_irq_disable(cmos
, RTC_AIE
);
356 CMOS_WRITE(hrs
, RTC_HOURS_ALARM
);
357 CMOS_WRITE(min
, RTC_MINUTES_ALARM
);
358 CMOS_WRITE(sec
, RTC_SECONDS_ALARM
);
360 /* the system may support an "enhanced" alarm */
361 if (cmos
->day_alrm
) {
362 CMOS_WRITE(mday
, cmos
->day_alrm
);
364 CMOS_WRITE(mon
, cmos
->mon_alrm
);
367 /* FIXME the HPET alarm glue currently ignores day_alrm
370 hpet_set_alarm_time(t
->time
.tm_hour
, t
->time
.tm_min
, t
->time
.tm_sec
);
373 cmos_irq_enable(cmos
, RTC_AIE
);
375 spin_unlock_irq(&rtc_lock
);
381 * Do not disable RTC alarm on shutdown - workaround for b0rked BIOSes.
383 static bool alarm_disable_quirk
;
385 static int __init
set_alarm_disable_quirk(const struct dmi_system_id
*id
)
387 alarm_disable_quirk
= true;
388 pr_info("rtc-cmos: BIOS has alarm-disable quirk. ");
389 pr_info("RTC alarms disabled\n");
393 static const struct dmi_system_id rtc_quirks
[] __initconst
= {
394 /* https://bugzilla.novell.com/show_bug.cgi?id=805740 */
396 .callback
= set_alarm_disable_quirk
,
397 .ident
= "IBM Truman",
399 DMI_MATCH(DMI_SYS_VENDOR
, "TOSHIBA"),
400 DMI_MATCH(DMI_PRODUCT_NAME
, "4852570"),
403 /* https://bugzilla.novell.com/show_bug.cgi?id=812592 */
405 .callback
= set_alarm_disable_quirk
,
406 .ident
= "Gigabyte GA-990XA-UD3",
408 DMI_MATCH(DMI_SYS_VENDOR
,
409 "Gigabyte Technology Co., Ltd."),
410 DMI_MATCH(DMI_PRODUCT_NAME
, "GA-990XA-UD3"),
413 /* http://permalink.gmane.org/gmane.linux.kernel/1604474 */
415 .callback
= set_alarm_disable_quirk
,
416 .ident
= "Toshiba Satellite L300",
418 DMI_MATCH(DMI_SYS_VENDOR
, "TOSHIBA"),
419 DMI_MATCH(DMI_PRODUCT_NAME
, "Satellite L300"),
425 static int cmos_alarm_irq_enable(struct device
*dev
, unsigned int enabled
)
427 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
430 if (!is_valid_irq(cmos
->irq
))
433 if (alarm_disable_quirk
)
436 spin_lock_irqsave(&rtc_lock
, flags
);
439 cmos_irq_enable(cmos
, RTC_AIE
);
441 cmos_irq_disable(cmos
, RTC_AIE
);
443 spin_unlock_irqrestore(&rtc_lock
, flags
);
447 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
449 static int cmos_procfs(struct device
*dev
, struct seq_file
*seq
)
451 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
452 unsigned char rtc_control
, valid
;
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
);
459 /* NOTE: at least ICH6 reports battery status using a different
460 * (non-RTC) bit; and SQWE is ignored on many current systems.
463 "periodic_IRQ\t: %s\n"
465 "HPET_emulated\t: %s\n"
466 // "square_wave\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",
478 (valid
& RTC_VRT
) ? "okay" : "dead");
484 #define cmos_procfs NULL
487 static const struct rtc_class_ops cmos_rtc_ops
= {
488 .read_time
= cmos_read_time
,
489 .set_time
= cmos_set_time
,
490 .read_alarm
= cmos_read_alarm
,
491 .set_alarm
= cmos_set_alarm
,
493 .alarm_irq_enable
= cmos_alarm_irq_enable
,
496 /*----------------------------------------------------------------*/
499 * All these chips have at least 64 bytes of address space, shared by
500 * RTC registers and NVRAM. Most of those bytes of NVRAM are used
501 * by boot firmware. Modern chips have 128 or 256 bytes.
504 #define NVRAM_OFFSET (RTC_REG_D + 1)
507 cmos_nvram_read(struct file
*filp
, struct kobject
*kobj
,
508 struct bin_attribute
*attr
,
509 char *buf
, loff_t off
, size_t count
)
513 if (unlikely(off
>= attr
->size
))
515 if (unlikely(off
< 0))
517 if ((off
+ count
) > attr
->size
)
518 count
= attr
->size
- off
;
521 spin_lock_irq(&rtc_lock
);
522 for (retval
= 0; count
; count
--, off
++, retval
++) {
524 *buf
++ = CMOS_READ(off
);
526 *buf
++ = cmos_read_bank2(off
);
530 spin_unlock_irq(&rtc_lock
);
536 cmos_nvram_write(struct file
*filp
, struct kobject
*kobj
,
537 struct bin_attribute
*attr
,
538 char *buf
, loff_t off
, size_t count
)
540 struct cmos_rtc
*cmos
;
543 cmos
= dev_get_drvdata(container_of(kobj
, struct device
, kobj
));
544 if (unlikely(off
>= attr
->size
))
546 if (unlikely(off
< 0))
548 if ((off
+ count
) > attr
->size
)
549 count
= attr
->size
- off
;
551 /* NOTE: on at least PCs and Ataris, the boot firmware uses a
552 * checksum on part of the NVRAM data. That's currently ignored
553 * here. If userspace is smart enough to know what fields of
554 * NVRAM to update, updating checksums is also part of its job.
557 spin_lock_irq(&rtc_lock
);
558 for (retval
= 0; count
; count
--, off
++, retval
++) {
559 /* don't trash RTC registers */
560 if (off
== cmos
->day_alrm
561 || off
== cmos
->mon_alrm
562 || off
== cmos
->century
)
565 CMOS_WRITE(*buf
++, off
);
567 cmos_write_bank2(*buf
++, off
);
571 spin_unlock_irq(&rtc_lock
);
576 static struct bin_attribute nvram
= {
579 .mode
= S_IRUGO
| S_IWUSR
,
582 .read
= cmos_nvram_read
,
583 .write
= cmos_nvram_write
,
584 /* size gets set up later */
587 /*----------------------------------------------------------------*/
589 static struct cmos_rtc cmos_rtc
;
591 static irqreturn_t
cmos_interrupt(int irq
, void *p
)
596 spin_lock(&rtc_lock
);
598 /* When the HPET interrupt handler calls us, the interrupt
599 * status is passed as arg1 instead of the irq number. But
600 * always clear irq status, even when HPET is in the way.
602 * Note that HPET and RTC are almost certainly out of phase,
603 * giving different IRQ status ...
605 irqstat
= CMOS_READ(RTC_INTR_FLAGS
);
606 rtc_control
= CMOS_READ(RTC_CONTROL
);
607 if (is_hpet_enabled())
608 irqstat
= (unsigned long)irq
& 0xF0;
610 /* If we were suspended, RTC_CONTROL may not be accurate since the
611 * bios may have cleared it.
613 if (!cmos_rtc
.suspend_ctrl
)
614 irqstat
&= (rtc_control
& RTC_IRQMASK
) | RTC_IRQF
;
616 irqstat
&= (cmos_rtc
.suspend_ctrl
& RTC_IRQMASK
) | RTC_IRQF
;
618 /* All Linux RTC alarms should be treated as if they were oneshot.
619 * Similar code may be needed in system wakeup paths, in case the
620 * alarm woke the system.
622 if (irqstat
& RTC_AIE
) {
623 cmos_rtc
.suspend_ctrl
&= ~RTC_AIE
;
624 rtc_control
&= ~RTC_AIE
;
625 CMOS_WRITE(rtc_control
, RTC_CONTROL
);
626 hpet_mask_rtc_irq_bit(RTC_AIE
);
627 CMOS_READ(RTC_INTR_FLAGS
);
629 spin_unlock(&rtc_lock
);
631 if (is_intr(irqstat
)) {
632 rtc_update_irq(p
, 1, irqstat
);
642 #define INITSECTION __init
645 static int INITSECTION
646 cmos_do_probe(struct device
*dev
, struct resource
*ports
, int rtc_irq
)
648 struct cmos_rtc_board_info
*info
= dev_get_platdata(dev
);
650 unsigned char rtc_control
;
651 unsigned address_space
;
654 /* there can be only one ... */
661 /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
663 * REVISIT non-x86 systems may instead use memory space resources
664 * (needing ioremap etc), not i/o space resources like this ...
667 ports
= request_region(ports
->start
, resource_size(ports
),
670 ports
= request_mem_region(ports
->start
, resource_size(ports
),
673 dev_dbg(dev
, "i/o registers already in use\n");
677 cmos_rtc
.irq
= rtc_irq
;
678 cmos_rtc
.iomem
= ports
;
680 /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
681 * driver did, but don't reject unknown configs. Old hardware
682 * won't address 128 bytes. Newer chips have multiple banks,
683 * though they may not be listed in one I/O resource.
685 #if defined(CONFIG_ATARI)
687 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
688 || defined(__sparc__) || defined(__mips__) \
689 || defined(__powerpc__)
692 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
695 if (can_bank2
&& ports
->end
> (ports
->start
+ 1))
698 /* For ACPI systems extension info comes from the FADT. On others,
699 * board specific setup provides it as appropriate. Systems where
700 * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
701 * some almost-clones) can provide hooks to make that behave.
703 * Note that ACPI doesn't preclude putting these registers into
704 * "extended" areas of the chip, including some that we won't yet
705 * expect CMOS_READ and friends to handle.
710 if (info
->address_space
)
711 address_space
= info
->address_space
;
713 if (info
->rtc_day_alarm
&& info
->rtc_day_alarm
< 128)
714 cmos_rtc
.day_alrm
= info
->rtc_day_alarm
;
715 if (info
->rtc_mon_alarm
&& info
->rtc_mon_alarm
< 128)
716 cmos_rtc
.mon_alrm
= info
->rtc_mon_alarm
;
717 if (info
->rtc_century
&& info
->rtc_century
< 128)
718 cmos_rtc
.century
= info
->rtc_century
;
720 if (info
->wake_on
&& info
->wake_off
) {
721 cmos_rtc
.wake_on
= info
->wake_on
;
722 cmos_rtc
.wake_off
= info
->wake_off
;
727 dev_set_drvdata(dev
, &cmos_rtc
);
729 cmos_rtc
.rtc
= rtc_device_register(driver_name
, dev
,
730 &cmos_rtc_ops
, THIS_MODULE
);
731 if (IS_ERR(cmos_rtc
.rtc
)) {
732 retval
= PTR_ERR(cmos_rtc
.rtc
);
736 rename_region(ports
, dev_name(&cmos_rtc
.rtc
->dev
));
738 spin_lock_irq(&rtc_lock
);
740 if (!(flags
& CMOS_RTC_FLAGS_NOFREQ
)) {
741 /* force periodic irq to CMOS reset default of 1024Hz;
743 * REVISIT it's been reported that at least one x86_64 ALI
744 * mobo doesn't use 32KHz here ... for portability we might
745 * need to do something about other clock frequencies.
747 cmos_rtc
.rtc
->irq_freq
= 1024;
748 hpet_set_periodic_freq(cmos_rtc
.rtc
->irq_freq
);
749 CMOS_WRITE(RTC_REF_CLCK_32KHZ
| 0x06, RTC_FREQ_SELECT
);
753 if (is_valid_irq(rtc_irq
))
754 cmos_irq_disable(&cmos_rtc
, RTC_PIE
| RTC_AIE
| RTC_UIE
);
756 rtc_control
= CMOS_READ(RTC_CONTROL
);
758 spin_unlock_irq(&rtc_lock
);
761 * <asm-generic/rtc.h> doesn't know 12-hour mode either.
763 if (is_valid_irq(rtc_irq
) && !(rtc_control
& RTC_24H
)) {
764 dev_warn(dev
, "only 24-hr supported\n");
769 if (is_valid_irq(rtc_irq
)) {
770 irq_handler_t rtc_cmos_int_handler
;
772 if (is_hpet_enabled()) {
773 rtc_cmos_int_handler
= hpet_rtc_interrupt
;
774 retval
= hpet_register_irq_handler(cmos_interrupt
);
776 dev_warn(dev
, "hpet_register_irq_handler "
777 " failed in rtc_init().");
781 rtc_cmos_int_handler
= cmos_interrupt
;
783 retval
= request_irq(rtc_irq
, rtc_cmos_int_handler
,
784 0, dev_name(&cmos_rtc
.rtc
->dev
),
787 dev_dbg(dev
, "IRQ %d is already in use\n", rtc_irq
);
791 hpet_rtc_timer_init();
793 /* export at least the first block of NVRAM */
794 nvram
.size
= address_space
- NVRAM_OFFSET
;
795 retval
= sysfs_create_bin_file(&dev
->kobj
, &nvram
);
797 dev_dbg(dev
, "can't create nvram file? %d\n", retval
);
801 dev_info(dev
, "%s%s, %zd bytes nvram%s\n",
802 !is_valid_irq(rtc_irq
) ? "no alarms" :
803 cmos_rtc
.mon_alrm
? "alarms up to one year" :
804 cmos_rtc
.day_alrm
? "alarms up to one month" :
805 "alarms up to one day",
806 cmos_rtc
.century
? ", y3k" : "",
808 is_hpet_enabled() ? ", hpet irqs" : "");
813 if (is_valid_irq(rtc_irq
))
814 free_irq(rtc_irq
, cmos_rtc
.rtc
);
817 rtc_device_unregister(cmos_rtc
.rtc
);
820 release_region(ports
->start
, resource_size(ports
));
822 release_mem_region(ports
->start
, resource_size(ports
));
826 static void cmos_do_shutdown(int rtc_irq
)
828 spin_lock_irq(&rtc_lock
);
829 if (is_valid_irq(rtc_irq
))
830 cmos_irq_disable(&cmos_rtc
, RTC_IRQMASK
);
831 spin_unlock_irq(&rtc_lock
);
834 static void __exit
cmos_do_remove(struct device
*dev
)
836 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
837 struct resource
*ports
;
839 cmos_do_shutdown(cmos
->irq
);
841 sysfs_remove_bin_file(&dev
->kobj
, &nvram
);
843 if (is_valid_irq(cmos
->irq
)) {
844 free_irq(cmos
->irq
, cmos
->rtc
);
845 hpet_unregister_irq_handler(cmos_interrupt
);
848 rtc_device_unregister(cmos
->rtc
);
853 release_region(ports
->start
, resource_size(ports
));
855 release_mem_region(ports
->start
, resource_size(ports
));
863 static int cmos_suspend(struct device
*dev
)
865 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
868 /* only the alarm might be a wakeup event source */
869 spin_lock_irq(&rtc_lock
);
870 cmos
->suspend_ctrl
= tmp
= CMOS_READ(RTC_CONTROL
);
871 if (tmp
& (RTC_PIE
|RTC_AIE
|RTC_UIE
)) {
874 if (device_may_wakeup(dev
))
875 mask
= RTC_IRQMASK
& ~RTC_AIE
;
879 CMOS_WRITE(tmp
, RTC_CONTROL
);
880 hpet_mask_rtc_irq_bit(mask
);
882 cmos_checkintr(cmos
, tmp
);
884 spin_unlock_irq(&rtc_lock
);
887 cmos
->enabled_wake
= 1;
891 enable_irq_wake(cmos
->irq
);
894 dev_dbg(dev
, "suspend%s, ctrl %02x\n",
895 (tmp
& RTC_AIE
) ? ", alarm may wake" : "",
901 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
902 * after a detour through G3 "mechanical off", although the ACPI spec
903 * says wakeup should only work from G1/S4 "hibernate". To most users,
904 * distinctions between S4 and S5 are pointless. So when the hardware
905 * allows, don't draw that distinction.
907 static inline int cmos_poweroff(struct device
*dev
)
909 return cmos_suspend(dev
);
912 #ifdef CONFIG_PM_SLEEP
914 static int cmos_resume(struct device
*dev
)
916 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
919 if (cmos
->enabled_wake
) {
923 disable_irq_wake(cmos
->irq
);
924 cmos
->enabled_wake
= 0;
927 spin_lock_irq(&rtc_lock
);
928 tmp
= cmos
->suspend_ctrl
;
929 cmos
->suspend_ctrl
= 0;
930 /* re-enable any irqs previously active */
931 if (tmp
& RTC_IRQMASK
) {
934 if (device_may_wakeup(dev
))
935 hpet_rtc_timer_init();
938 CMOS_WRITE(tmp
, RTC_CONTROL
);
939 hpet_set_rtc_irq_bit(tmp
& RTC_IRQMASK
);
941 mask
= CMOS_READ(RTC_INTR_FLAGS
);
942 mask
&= (tmp
& RTC_IRQMASK
) | RTC_IRQF
;
943 if (!is_hpet_enabled() || !is_intr(mask
))
946 /* force one-shot behavior if HPET blocked
947 * the wake alarm's irq
949 rtc_update_irq(cmos
->rtc
, 1, mask
);
951 hpet_mask_rtc_irq_bit(RTC_AIE
);
952 } while (mask
& RTC_AIE
);
954 spin_unlock_irq(&rtc_lock
);
956 dev_dbg(dev
, "resume, ctrl %02x\n", tmp
);
964 static inline int cmos_poweroff(struct device
*dev
)
971 static SIMPLE_DEV_PM_OPS(cmos_pm_ops
, cmos_suspend
, cmos_resume
);
973 /*----------------------------------------------------------------*/
975 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
976 * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
977 * probably list them in similar PNPBIOS tables; so PNP is more common.
979 * We don't use legacy "poke at the hardware" probing. Ancient PCs that
980 * predate even PNPBIOS should set up platform_bus devices.
985 #include <linux/acpi.h>
987 static u32
rtc_handler(void *context
)
989 struct device
*dev
= context
;
991 pm_wakeup_event(dev
, 0);
992 acpi_clear_event(ACPI_EVENT_RTC
);
993 acpi_disable_event(ACPI_EVENT_RTC
, 0);
994 return ACPI_INTERRUPT_HANDLED
;
997 static inline void rtc_wake_setup(struct device
*dev
)
999 acpi_install_fixed_event_handler(ACPI_EVENT_RTC
, rtc_handler
, dev
);
1001 * After the RTC handler is installed, the Fixed_RTC event should
1002 * be disabled. Only when the RTC alarm is set will it be enabled.
1004 acpi_clear_event(ACPI_EVENT_RTC
);
1005 acpi_disable_event(ACPI_EVENT_RTC
, 0);
1008 static void rtc_wake_on(struct device
*dev
)
1010 acpi_clear_event(ACPI_EVENT_RTC
);
1011 acpi_enable_event(ACPI_EVENT_RTC
, 0);
1014 static void rtc_wake_off(struct device
*dev
)
1016 acpi_disable_event(ACPI_EVENT_RTC
, 0);
1019 /* Every ACPI platform has a mc146818 compatible "cmos rtc". Here we find
1020 * its device node and pass extra config data. This helps its driver use
1021 * capabilities that the now-obsolete mc146818 didn't have, and informs it
1022 * that this board's RTC is wakeup-capable (per ACPI spec).
1024 static struct cmos_rtc_board_info acpi_rtc_info
;
1026 static void cmos_wake_setup(struct device
*dev
)
1031 rtc_wake_setup(dev
);
1032 acpi_rtc_info
.wake_on
= rtc_wake_on
;
1033 acpi_rtc_info
.wake_off
= rtc_wake_off
;
1035 /* workaround bug in some ACPI tables */
1036 if (acpi_gbl_FADT
.month_alarm
&& !acpi_gbl_FADT
.day_alarm
) {
1037 dev_dbg(dev
, "bogus FADT month_alarm (%d)\n",
1038 acpi_gbl_FADT
.month_alarm
);
1039 acpi_gbl_FADT
.month_alarm
= 0;
1042 acpi_rtc_info
.rtc_day_alarm
= acpi_gbl_FADT
.day_alarm
;
1043 acpi_rtc_info
.rtc_mon_alarm
= acpi_gbl_FADT
.month_alarm
;
1044 acpi_rtc_info
.rtc_century
= acpi_gbl_FADT
.century
;
1046 /* NOTE: S4_RTC_WAKE is NOT currently useful to Linux */
1047 if (acpi_gbl_FADT
.flags
& ACPI_FADT_S4_RTC_WAKE
)
1048 dev_info(dev
, "RTC can wake from S4\n");
1050 dev
->platform_data
= &acpi_rtc_info
;
1052 /* RTC always wakes from S1/S2/S3, and often S4/STD */
1053 device_init_wakeup(dev
, 1);
1058 static void cmos_wake_setup(struct device
*dev
)
1066 #include <linux/pnp.h>
1068 static int cmos_pnp_probe(struct pnp_dev
*pnp
, const struct pnp_device_id
*id
)
1070 cmos_wake_setup(&pnp
->dev
);
1072 if (pnp_port_start(pnp
, 0) == 0x70 && !pnp_irq_valid(pnp
, 0))
1073 /* Some machines contain a PNP entry for the RTC, but
1074 * don't define the IRQ. It should always be safe to
1075 * hardcode it in these cases
1077 return cmos_do_probe(&pnp
->dev
,
1078 pnp_get_resource(pnp
, IORESOURCE_IO
, 0), 8);
1080 return cmos_do_probe(&pnp
->dev
,
1081 pnp_get_resource(pnp
, IORESOURCE_IO
, 0),
1085 static void __exit
cmos_pnp_remove(struct pnp_dev
*pnp
)
1087 cmos_do_remove(&pnp
->dev
);
1090 static void cmos_pnp_shutdown(struct pnp_dev
*pnp
)
1092 struct device
*dev
= &pnp
->dev
;
1093 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
1095 if (system_state
== SYSTEM_POWER_OFF
&& !cmos_poweroff(dev
))
1098 cmos_do_shutdown(cmos
->irq
);
1101 static const struct pnp_device_id rtc_ids
[] = {
1102 { .id
= "PNP0b00", },
1103 { .id
= "PNP0b01", },
1104 { .id
= "PNP0b02", },
1107 MODULE_DEVICE_TABLE(pnp
, rtc_ids
);
1109 static struct pnp_driver cmos_pnp_driver
= {
1110 .name
= (char *) driver_name
,
1111 .id_table
= rtc_ids
,
1112 .probe
= cmos_pnp_probe
,
1113 .remove
= __exit_p(cmos_pnp_remove
),
1114 .shutdown
= cmos_pnp_shutdown
,
1116 /* flag ensures resume() gets called, and stops syslog spam */
1117 .flags
= PNP_DRIVER_RES_DO_NOT_CHANGE
,
1123 #endif /* CONFIG_PNP */
1126 static const struct of_device_id of_cmos_match
[] = {
1128 .compatible
= "motorola,mc146818",
1132 MODULE_DEVICE_TABLE(of
, of_cmos_match
);
1134 static __init
void cmos_of_init(struct platform_device
*pdev
)
1136 struct device_node
*node
= pdev
->dev
.of_node
;
1137 struct rtc_time time
;
1144 val
= of_get_property(node
, "ctrl-reg", NULL
);
1146 CMOS_WRITE(be32_to_cpup(val
), RTC_CONTROL
);
1148 val
= of_get_property(node
, "freq-reg", NULL
);
1150 CMOS_WRITE(be32_to_cpup(val
), RTC_FREQ_SELECT
);
1152 get_rtc_time(&time
);
1153 ret
= rtc_valid_tm(&time
);
1155 struct rtc_time def_time
= {
1159 set_rtc_time(&def_time
);
1163 static inline void cmos_of_init(struct platform_device
*pdev
) {}
1165 /*----------------------------------------------------------------*/
1167 /* Platform setup should have set up an RTC device, when PNP is
1168 * unavailable ... this could happen even on (older) PCs.
1171 static int __init
cmos_platform_probe(struct platform_device
*pdev
)
1173 struct resource
*resource
;
1177 cmos_wake_setup(&pdev
->dev
);
1180 resource
= platform_get_resource(pdev
, IORESOURCE_IO
, 0);
1182 resource
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
1183 irq
= platform_get_irq(pdev
, 0);
1187 return cmos_do_probe(&pdev
->dev
, resource
, irq
);
1190 static int __exit
cmos_platform_remove(struct platform_device
*pdev
)
1192 cmos_do_remove(&pdev
->dev
);
1196 static void cmos_platform_shutdown(struct platform_device
*pdev
)
1198 struct device
*dev
= &pdev
->dev
;
1199 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
1201 if (system_state
== SYSTEM_POWER_OFF
&& !cmos_poweroff(dev
))
1204 cmos_do_shutdown(cmos
->irq
);
1207 /* work with hotplug and coldplug */
1208 MODULE_ALIAS("platform:rtc_cmos");
1210 static struct platform_driver cmos_platform_driver
= {
1211 .remove
= __exit_p(cmos_platform_remove
),
1212 .shutdown
= cmos_platform_shutdown
,
1214 .name
= driver_name
,
1218 .of_match_table
= of_match_ptr(of_cmos_match
),
1223 static bool pnp_driver_registered
;
1225 static bool platform_driver_registered
;
1227 static int __init
cmos_init(void)
1232 retval
= pnp_register_driver(&cmos_pnp_driver
);
1234 pnp_driver_registered
= true;
1237 if (!cmos_rtc
.dev
) {
1238 retval
= platform_driver_probe(&cmos_platform_driver
,
1239 cmos_platform_probe
);
1241 platform_driver_registered
= true;
1244 dmi_check_system(rtc_quirks
);
1250 if (pnp_driver_registered
)
1251 pnp_unregister_driver(&cmos_pnp_driver
);
1255 module_init(cmos_init
);
1257 static void __exit
cmos_exit(void)
1260 if (pnp_driver_registered
)
1261 pnp_unregister_driver(&cmos_pnp_driver
);
1263 if (platform_driver_registered
)
1264 platform_driver_unregister(&cmos_platform_driver
);
1266 module_exit(cmos_exit
);
1269 MODULE_AUTHOR("David Brownell");
1270 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1271 MODULE_LICENSE("GPL");