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	int ret;
 226
 227	/*
 228	 * If pm_trace abused the RTC for storage, set the timespec to 0,
 229	 * which tells the caller that this RTC value is unusable.
 230	 */
 231	if (!pm_trace_rtc_valid())
 232		return -EIO;
 233
 234	ret = mc146818_get_time(t, 1000);
 235	if (ret < 0) {
 236		dev_err_ratelimited(dev, "unable to read current time\n");
 237		return ret;
 238	}
 239
 240	return 0;
 241}
 242
 243static int cmos_set_time(struct device *dev, struct rtc_time *t)
 244{
 245	/* NOTE: this ignores the issue whereby updating the seconds
 246	 * takes effect exactly 500ms after we write the register.
 247	 * (Also queueing and other delays before we get this far.)
 248	 */
 249	return mc146818_set_time(t);
 250}
 251
 252struct cmos_read_alarm_callback_param {
 253	struct cmos_rtc *cmos;
 254	struct rtc_time *time;
 255	unsigned char	rtc_control;
 256};
 257
 258static void cmos_read_alarm_callback(unsigned char __always_unused seconds,
 259				     void *param_in)
 260{
 261	struct cmos_read_alarm_callback_param *p =
 262		(struct cmos_read_alarm_callback_param *)param_in;
 263	struct rtc_time *time = p->time;
 264
 265	time->tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
 266	time->tm_min = CMOS_READ(RTC_MINUTES_ALARM);
 267	time->tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 268
 269	if (p->cmos->day_alrm) {
 270		/* ignore upper bits on readback per ACPI spec */
 271		time->tm_mday = CMOS_READ(p->cmos->day_alrm) & 0x3f;
 272		if (!time->tm_mday)
 273			time->tm_mday = -1;
 274
 275		if (p->cmos->mon_alrm) {
 276			time->tm_mon = CMOS_READ(p->cmos->mon_alrm);
 277			if (!time->tm_mon)
 278				time->tm_mon = -1;
 279		}
 280	}
 281
 282	p->rtc_control = CMOS_READ(RTC_CONTROL);
 283}
 284
 285static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 286{
 287	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
 288	struct cmos_read_alarm_callback_param p = {
 289		.cmos = cmos,
 290		.time = &t->time,
 291	};
 292
 293	/* This not only a rtc_op, but also called directly */
 294	if (!is_valid_irq(cmos->irq))
 295		return -ETIMEDOUT;
 296
 297	/* Basic alarms only support hour, minute, and seconds fields.
 298	 * Some also support day and month, for alarms up to a year in
 299	 * the future.
 300	 */
 301
 302	/* Some Intel chipsets disconnect the alarm registers when the clock
 303	 * update is in progress - during this time reads return bogus values
 304	 * and writes may fail silently. See for example "7th Generation Intel®
 305	 * Processor Family I/O for U/Y Platforms [...] Datasheet", section
 306	 * 27.7.1
 307	 *
 308	 * Use the mc146818_avoid_UIP() function to avoid this.
 309	 */
 310	if (!mc146818_avoid_UIP(cmos_read_alarm_callback, 10, &p))
 311		return -EIO;
 312
 313	if (!(p.rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 314		if (((unsigned)t->time.tm_sec) < 0x60)
 315			t->time.tm_sec = bcd2bin(t->time.tm_sec);
 316		else
 317			t->time.tm_sec = -1;
 318		if (((unsigned)t->time.tm_min) < 0x60)
 319			t->time.tm_min = bcd2bin(t->time.tm_min);
 320		else
 321			t->time.tm_min = -1;
 322		if (((unsigned)t->time.tm_hour) < 0x24)
 323			t->time.tm_hour = bcd2bin(t->time.tm_hour);
 324		else
 325			t->time.tm_hour = -1;
 326
 327		if (cmos->day_alrm) {
 328			if (((unsigned)t->time.tm_mday) <= 0x31)
 329				t->time.tm_mday = bcd2bin(t->time.tm_mday);
 330			else
 331				t->time.tm_mday = -1;
 332
 333			if (cmos->mon_alrm) {
 334				if (((unsigned)t->time.tm_mon) <= 0x12)
 335					t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
 336				else
 337					t->time.tm_mon = -1;
 338			}
 339		}
 340	}
 341
 342	t->enabled = !!(p.rtc_control & RTC_AIE);
 343	t->pending = 0;
 344
 345	return 0;
 346}
 347
 348static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
 349{
 350	unsigned char	rtc_intr;
 351
 352	/* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
 353	 * allegedly some older rtcs need that to handle irqs properly
 354	 */
 355	rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 356
 357	if (use_hpet_alarm())
 358		return;
 359
 360	rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 361	if (is_intr(rtc_intr))
 362		rtc_update_irq(cmos->rtc, 1, rtc_intr);
 363}
 364
 365static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
 366{
 367	unsigned char	rtc_control;
 368
 369	/* flush any pending IRQ status, notably for update irqs,
 370	 * before we enable new IRQs
 371	 */
 372	rtc_control = CMOS_READ(RTC_CONTROL);
 373	cmos_checkintr(cmos, rtc_control);
 374
 375	rtc_control |= mask;
 376	CMOS_WRITE(rtc_control, RTC_CONTROL);
 377	if (use_hpet_alarm())
 378		hpet_set_rtc_irq_bit(mask);
 379
 380	if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
 381		if (cmos->wake_on)
 382			cmos->wake_on(cmos->dev);
 383	}
 384
 385	cmos_checkintr(cmos, rtc_control);
 386}
 387
 388static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
 389{
 390	unsigned char	rtc_control;
 391
 392	rtc_control = CMOS_READ(RTC_CONTROL);
 393	rtc_control &= ~mask;
 394	CMOS_WRITE(rtc_control, RTC_CONTROL);
 395	if (use_hpet_alarm())
 396		hpet_mask_rtc_irq_bit(mask);
 397
 398	if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
 399		if (cmos->wake_off)
 400			cmos->wake_off(cmos->dev);
 401	}
 402
 403	cmos_checkintr(cmos, rtc_control);
 404}
 405
 406static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t)
 407{
 408	struct cmos_rtc *cmos = dev_get_drvdata(dev);
 409	struct rtc_time now;
 410
 411	cmos_read_time(dev, &now);
 412
 413	if (!cmos->day_alrm) {
 414		time64_t t_max_date;
 415		time64_t t_alrm;
 416
 417		t_max_date = rtc_tm_to_time64(&now);
 418		t_max_date += 24 * 60 * 60 - 1;
 419		t_alrm = rtc_tm_to_time64(&t->time);
 420		if (t_alrm > t_max_date) {
 421			dev_err(dev,
 422				"Alarms can be up to one day in the future\n");
 423			return -EINVAL;
 424		}
 425	} else if (!cmos->mon_alrm) {
 426		struct rtc_time max_date = now;
 427		time64_t t_max_date;
 428		time64_t t_alrm;
 429		int max_mday;
 430
 431		if (max_date.tm_mon == 11) {
 432			max_date.tm_mon = 0;
 433			max_date.tm_year += 1;
 434		} else {
 435			max_date.tm_mon += 1;
 436		}
 437		max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 438		if (max_date.tm_mday > max_mday)
 439			max_date.tm_mday = max_mday;
 440
 441		t_max_date = rtc_tm_to_time64(&max_date);
 442		t_max_date -= 1;
 443		t_alrm = rtc_tm_to_time64(&t->time);
 444		if (t_alrm > t_max_date) {
 445			dev_err(dev,
 446				"Alarms can be up to one month in the future\n");
 447			return -EINVAL;
 448		}
 449	} else {
 450		struct rtc_time max_date = now;
 451		time64_t t_max_date;
 452		time64_t t_alrm;
 453		int max_mday;
 454
 455		max_date.tm_year += 1;
 456		max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 457		if (max_date.tm_mday > max_mday)
 458			max_date.tm_mday = max_mday;
 459
 460		t_max_date = rtc_tm_to_time64(&max_date);
 461		t_max_date -= 1;
 462		t_alrm = rtc_tm_to_time64(&t->time);
 463		if (t_alrm > t_max_date) {
 464			dev_err(dev,
 465				"Alarms can be up to one year in the future\n");
 466			return -EINVAL;
 467		}
 468	}
 469
 470	return 0;
 471}
 472
 473struct cmos_set_alarm_callback_param {
 474	struct cmos_rtc *cmos;
 475	unsigned char mon, mday, hrs, min, sec;
 476	struct rtc_wkalrm *t;
 477};
 478
 479/* Note: this function may be executed by mc146818_avoid_UIP() more then
 480 *	 once
 481 */
 482static void cmos_set_alarm_callback(unsigned char __always_unused seconds,
 483				    void *param_in)
 484{
 485	struct cmos_set_alarm_callback_param *p =
 486		(struct cmos_set_alarm_callback_param *)param_in;
 487
 488	/* next rtc irq must not be from previous alarm setting */
 489	cmos_irq_disable(p->cmos, RTC_AIE);
 490
 491	/* update alarm */
 492	CMOS_WRITE(p->hrs, RTC_HOURS_ALARM);
 493	CMOS_WRITE(p->min, RTC_MINUTES_ALARM);
 494	CMOS_WRITE(p->sec, RTC_SECONDS_ALARM);
 495
 496	/* the system may support an "enhanced" alarm */
 497	if (p->cmos->day_alrm) {
 498		CMOS_WRITE(p->mday, p->cmos->day_alrm);
 499		if (p->cmos->mon_alrm)
 500			CMOS_WRITE(p->mon, p->cmos->mon_alrm);
 501	}
 502
 503	if (use_hpet_alarm()) {
 504		/*
 505		 * FIXME the HPET alarm glue currently ignores day_alrm
 506		 * and mon_alrm ...
 507		 */
 508		hpet_set_alarm_time(p->t->time.tm_hour, p->t->time.tm_min,
 509				    p->t->time.tm_sec);
 510	}
 511
 512	if (p->t->enabled)
 513		cmos_irq_enable(p->cmos, RTC_AIE);
 514}
 515
 516static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 517{
 518	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
 519	struct cmos_set_alarm_callback_param p = {
 520		.cmos = cmos,
 521		.t = t
 522	};
 523	unsigned char rtc_control;
 524	int ret;
 525
 526	/* This not only a rtc_op, but also called directly */
 527	if (!is_valid_irq(cmos->irq))
 528		return -EIO;
 529
 530	ret = cmos_validate_alarm(dev, t);
 531	if (ret < 0)
 532		return ret;
 533
 534	p.mon = t->time.tm_mon + 1;
 535	p.mday = t->time.tm_mday;
 536	p.hrs = t->time.tm_hour;
 537	p.min = t->time.tm_min;
 538	p.sec = t->time.tm_sec;
 539
 540	spin_lock_irq(&rtc_lock);
 541	rtc_control = CMOS_READ(RTC_CONTROL);
 542	spin_unlock_irq(&rtc_lock);
 543
 544	if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 545		/* Writing 0xff means "don't care" or "match all".  */
 546		p.mon = (p.mon <= 12) ? bin2bcd(p.mon) : 0xff;
 547		p.mday = (p.mday >= 1 && p.mday <= 31) ? bin2bcd(p.mday) : 0xff;
 548		p.hrs = (p.hrs < 24) ? bin2bcd(p.hrs) : 0xff;
 549		p.min = (p.min < 60) ? bin2bcd(p.min) : 0xff;
 550		p.sec = (p.sec < 60) ? bin2bcd(p.sec) : 0xff;
 551	}
 552
 553	/*
 554	 * Some Intel chipsets disconnect the alarm registers when the clock
 555	 * update is in progress - during this time writes fail silently.
 556	 *
 557	 * Use mc146818_avoid_UIP() to avoid this.
 558	 */
 559	if (!mc146818_avoid_UIP(cmos_set_alarm_callback, 10, &p))
 560		return -ETIMEDOUT;
 561
 562	cmos->alarm_expires = rtc_tm_to_time64(&t->time);
 563
 564	return 0;
 565}
 566
 567static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 568{
 569	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
 570	unsigned long	flags;
 571
 572	spin_lock_irqsave(&rtc_lock, flags);
 573
 574	if (enabled)
 575		cmos_irq_enable(cmos, RTC_AIE);
 576	else
 577		cmos_irq_disable(cmos, RTC_AIE);
 578
 579	spin_unlock_irqrestore(&rtc_lock, flags);
 580	return 0;
 581}
 582
 583#if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 584
 585static int cmos_procfs(struct device *dev, struct seq_file *seq)
 586{
 587	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
 588	unsigned char	rtc_control, valid;
 589
 590	spin_lock_irq(&rtc_lock);
 591	rtc_control = CMOS_READ(RTC_CONTROL);
 592	valid = CMOS_READ(RTC_VALID);
 593	spin_unlock_irq(&rtc_lock);
 594
 595	/* NOTE:  at least ICH6 reports battery status using a different
 596	 * (non-RTC) bit; and SQWE is ignored on many current systems.
 597	 */
 598	seq_printf(seq,
 599		   "periodic_IRQ\t: %s\n"
 600		   "update_IRQ\t: %s\n"
 601		   "HPET_emulated\t: %s\n"
 602		   // "square_wave\t: %s\n"
 603		   "BCD\t\t: %s\n"
 604		   "DST_enable\t: %s\n"
 605		   "periodic_freq\t: %d\n"
 606		   "batt_status\t: %s\n",
 607		   (rtc_control & RTC_PIE) ? "yes" : "no",
 608		   (rtc_control & RTC_UIE) ? "yes" : "no",
 609		   use_hpet_alarm() ? "yes" : "no",
 610		   // (rtc_control & RTC_SQWE) ? "yes" : "no",
 611		   (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 612		   (rtc_control & RTC_DST_EN) ? "yes" : "no",
 613		   cmos->rtc->irq_freq,
 614		   (valid & RTC_VRT) ? "okay" : "dead");
 615
 616	return 0;
 617}
 618
 619#else
 620#define	cmos_procfs	NULL
 621#endif
 622
 623static const struct rtc_class_ops cmos_rtc_ops = {
 624	.read_time		= cmos_read_time,
 625	.set_time		= cmos_set_time,
 626	.read_alarm		= cmos_read_alarm,
 627	.set_alarm		= cmos_set_alarm,
 628	.proc			= cmos_procfs,
 629	.alarm_irq_enable	= cmos_alarm_irq_enable,
 630};
 631
 632/*----------------------------------------------------------------*/
 633
 634/*
 635 * All these chips have at least 64 bytes of address space, shared by
 636 * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 637 * by boot firmware.  Modern chips have 128 or 256 bytes.
 638 */
 639
 640#define NVRAM_OFFSET	(RTC_REG_D + 1)
 641
 642static int cmos_nvram_read(void *priv, unsigned int off, void *val,
 643			   size_t count)
 644{
 645	unsigned char *buf = val;
 
 646
 647	off += NVRAM_OFFSET;
 648	for (; count; count--, off++, buf++) {
 649		guard(spinlock_irq)(&rtc_lock);
 650		if (off < 128)
 651			*buf = CMOS_READ(off);
 652		else if (can_bank2)
 653			*buf = cmos_read_bank2(off);
 654		else
 655			return -EIO;
 656	}
 
 657
 658	return 0;
 659}
 660
 661static int cmos_nvram_write(void *priv, unsigned int off, void *val,
 662			    size_t count)
 663{
 664	struct cmos_rtc	*cmos = priv;
 665	unsigned char	*buf = val;
 
 666
 667	/* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 668	 * checksum on part of the NVRAM data.  That's currently ignored
 669	 * here.  If userspace is smart enough to know what fields of
 670	 * NVRAM to update, updating checksums is also part of its job.
 671	 */
 672	off += NVRAM_OFFSET;
 673	for (; count; count--, off++, buf++) {
 
 674		/* don't trash RTC registers */
 675		if (off == cmos->day_alrm
 676				|| off == cmos->mon_alrm
 677				|| off == cmos->century)
 678			continue;
 679
 680		guard(spinlock_irq)(&rtc_lock);
 681		if (off < 128)
 682			CMOS_WRITE(*buf, off);
 683		else if (can_bank2)
 684			cmos_write_bank2(*buf, off);
 685		else
 686			return -EIO;
 687	}
 
 688
 689	return 0;
 690}
 691
 692/*----------------------------------------------------------------*/
 693
 694static struct cmos_rtc	cmos_rtc;
 695
 696static irqreturn_t cmos_interrupt(int irq, void *p)
 697{
 698	u8		irqstat;
 699	u8		rtc_control;
 700
 701	spin_lock(&rtc_lock);
 702
 703	/* When the HPET interrupt handler calls us, the interrupt
 704	 * status is passed as arg1 instead of the irq number.  But
 705	 * always clear irq status, even when HPET is in the way.
 706	 *
 707	 * Note that HPET and RTC are almost certainly out of phase,
 708	 * giving different IRQ status ...
 709	 */
 710	irqstat = CMOS_READ(RTC_INTR_FLAGS);
 711	rtc_control = CMOS_READ(RTC_CONTROL);
 712	if (use_hpet_alarm())
 713		irqstat = (unsigned long)irq & 0xF0;
 714
 715	/* If we were suspended, RTC_CONTROL may not be accurate since the
 716	 * bios may have cleared it.
 717	 */
 718	if (!cmos_rtc.suspend_ctrl)
 719		irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 720	else
 721		irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 722
 723	/* All Linux RTC alarms should be treated as if they were oneshot.
 724	 * Similar code may be needed in system wakeup paths, in case the
 725	 * alarm woke the system.
 726	 */
 727	if (irqstat & RTC_AIE) {
 728		cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 729		rtc_control &= ~RTC_AIE;
 730		CMOS_WRITE(rtc_control, RTC_CONTROL);
 731		if (use_hpet_alarm())
 732			hpet_mask_rtc_irq_bit(RTC_AIE);
 733		CMOS_READ(RTC_INTR_FLAGS);
 734	}
 735	spin_unlock(&rtc_lock);
 736
 737	if (is_intr(irqstat)) {
 738		rtc_update_irq(p, 1, irqstat);
 739		return IRQ_HANDLED;
 740	} else
 741		return IRQ_NONE;
 742}
 743
 744#ifdef	CONFIG_ACPI
 745
 746#include <linux/acpi.h>
 747
 748static u32 rtc_handler(void *context)
 749{
 750	struct device *dev = context;
 751	struct cmos_rtc *cmos = dev_get_drvdata(dev);
 752	unsigned char rtc_control = 0;
 753	unsigned char rtc_intr;
 754	unsigned long flags;
 755
 756
 757	/*
 758	 * Always update rtc irq when ACPI is used as RTC Alarm.
 759	 * Or else, ACPI SCI is enabled during suspend/resume only,
 760	 * update rtc irq in that case.
 761	 */
 762	if (cmos_use_acpi_alarm())
 763		cmos_interrupt(0, (void *)cmos->rtc);
 764	else {
 765		/* Fix me: can we use cmos_interrupt() here as well? */
 766		spin_lock_irqsave(&rtc_lock, flags);
 767		if (cmos_rtc.suspend_ctrl)
 768			rtc_control = CMOS_READ(RTC_CONTROL);
 769		if (rtc_control & RTC_AIE) {
 770			cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 771			CMOS_WRITE(rtc_control, RTC_CONTROL);
 772			rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 773			rtc_update_irq(cmos->rtc, 1, rtc_intr);
 774		}
 775		spin_unlock_irqrestore(&rtc_lock, flags);
 776	}
 777
 778	pm_wakeup_hard_event(dev);
 779	acpi_clear_event(ACPI_EVENT_RTC);
 780	acpi_disable_event(ACPI_EVENT_RTC, 0);
 781	return ACPI_INTERRUPT_HANDLED;
 782}
 783
 784static void acpi_rtc_event_setup(struct device *dev)
 785{
 786	if (acpi_disabled)
 787		return;
 788
 789	acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
 790	/*
 791	 * After the RTC handler is installed, the Fixed_RTC event should
 792	 * be disabled. Only when the RTC alarm is set will it be enabled.
 793	 */
 794	acpi_clear_event(ACPI_EVENT_RTC);
 795	acpi_disable_event(ACPI_EVENT_RTC, 0);
 796}
 797
 798static void acpi_rtc_event_cleanup(void)
 799{
 800	if (acpi_disabled)
 801		return;
 802
 803	acpi_remove_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler);
 804}
 805
 806static void rtc_wake_on(struct device *dev)
 807{
 808	acpi_clear_event(ACPI_EVENT_RTC);
 809	acpi_enable_event(ACPI_EVENT_RTC, 0);
 810}
 811
 812static void rtc_wake_off(struct device *dev)
 813{
 814	acpi_disable_event(ACPI_EVENT_RTC, 0);
 815}
 816
 817#ifdef CONFIG_X86
 
 818static void use_acpi_alarm_quirks(void)
 819{
 820	switch (boot_cpu_data.x86_vendor) {
 821	case X86_VENDOR_INTEL:
 822		if (dmi_get_bios_year() < 2015)
 823			return;
 824		break;
 825	case X86_VENDOR_AMD:
 826	case X86_VENDOR_HYGON:
 827		if (dmi_get_bios_year() < 2021)
 828			return;
 829		break;
 830	default:
 831		return;
 832	}
 833	if (!is_hpet_enabled())
 834		return;
 835
 
 
 
 836	use_acpi_alarm = true;
 837}
 838#else
 839static inline void use_acpi_alarm_quirks(void) { }
 840#endif
 841
 842static void acpi_cmos_wake_setup(struct device *dev)
 843{
 844	if (acpi_disabled)
 845		return;
 846
 847	use_acpi_alarm_quirks();
 848
 849	cmos_rtc.wake_on = rtc_wake_on;
 850	cmos_rtc.wake_off = rtc_wake_off;
 851
 852	/* ACPI tables bug workaround. */
 853	if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
 854		dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
 855			acpi_gbl_FADT.month_alarm);
 856		acpi_gbl_FADT.month_alarm = 0;
 857	}
 858
 859	cmos_rtc.day_alrm = acpi_gbl_FADT.day_alarm;
 860	cmos_rtc.mon_alrm = acpi_gbl_FADT.month_alarm;
 861	cmos_rtc.century = acpi_gbl_FADT.century;
 862
 863	if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
 864		dev_info(dev, "RTC can wake from S4\n");
 865
 866	/* RTC always wakes from S1/S2/S3, and often S4/STD */
 867	device_init_wakeup(dev, 1);
 868}
 869
 870static void cmos_check_acpi_rtc_status(struct device *dev,
 871					      unsigned char *rtc_control)
 872{
 873	struct cmos_rtc *cmos = dev_get_drvdata(dev);
 874	acpi_event_status rtc_status;
 875	acpi_status status;
 876
 877	if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
 878		return;
 879
 880	status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
 881	if (ACPI_FAILURE(status)) {
 882		dev_err(dev, "Could not get RTC status\n");
 883	} else if (rtc_status & ACPI_EVENT_FLAG_SET) {
 884		unsigned char mask;
 885		*rtc_control &= ~RTC_AIE;
 886		CMOS_WRITE(*rtc_control, RTC_CONTROL);
 887		mask = CMOS_READ(RTC_INTR_FLAGS);
 888		rtc_update_irq(cmos->rtc, 1, mask);
 889	}
 890}
 891
 892#else /* !CONFIG_ACPI */
 893
 894static inline void acpi_rtc_event_setup(struct device *dev)
 895{
 896}
 897
 898static inline void acpi_rtc_event_cleanup(void)
 899{
 900}
 901
 902static inline void acpi_cmos_wake_setup(struct device *dev)
 903{
 904}
 905
 906static inline void cmos_check_acpi_rtc_status(struct device *dev,
 907					      unsigned char *rtc_control)
 908{
 909}
 910#endif /* CONFIG_ACPI */
 911
 912#ifdef	CONFIG_PNP
 913#define	INITSECTION
 914
 915#else
 916#define	INITSECTION	__init
 917#endif
 918
 919#define SECS_PER_DAY	(24 * 60 * 60)
 920#define SECS_PER_MONTH	(28 * SECS_PER_DAY)
 921#define SECS_PER_YEAR	(365 * SECS_PER_DAY)
 922
 923static int INITSECTION
 924cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 925{
 926	struct cmos_rtc_board_info	*info = dev_get_platdata(dev);
 927	int				retval = 0;
 928	unsigned char			rtc_control;
 929	unsigned			address_space;
 930	u32				flags = 0;
 931	struct nvmem_config nvmem_cfg = {
 932		.name = "cmos_nvram",
 933		.word_size = 1,
 934		.stride = 1,
 935		.reg_read = cmos_nvram_read,
 936		.reg_write = cmos_nvram_write,
 937		.priv = &cmos_rtc,
 938	};
 939
 940	/* there can be only one ... */
 941	if (cmos_rtc.dev)
 942		return -EBUSY;
 943
 944	if (!ports)
 945		return -ENODEV;
 946
 947	/* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 948	 *
 949	 * REVISIT non-x86 systems may instead use memory space resources
 950	 * (needing ioremap etc), not i/o space resources like this ...
 951	 */
 952	if (RTC_IOMAPPED)
 953		ports = request_region(ports->start, resource_size(ports),
 954				       driver_name);
 955	else
 956		ports = request_mem_region(ports->start, resource_size(ports),
 957					   driver_name);
 958	if (!ports) {
 959		dev_dbg(dev, "i/o registers already in use\n");
 960		return -EBUSY;
 961	}
 962
 963	cmos_rtc.irq = rtc_irq;
 964	cmos_rtc.iomem = ports;
 965
 966	/* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 967	 * driver did, but don't reject unknown configs.   Old hardware
 968	 * won't address 128 bytes.  Newer chips have multiple banks,
 969	 * though they may not be listed in one I/O resource.
 970	 */
 971#if	defined(CONFIG_ATARI)
 972	address_space = 64;
 973#elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 974			|| defined(__sparc__) || defined(__mips__) \
 975			|| defined(__powerpc__)
 976	address_space = 128;
 977#else
 978#warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 979	address_space = 128;
 980#endif
 981	if (can_bank2 && ports->end > (ports->start + 1))
 982		address_space = 256;
 983
 984	/* For ACPI systems extension info comes from the FADT.  On others,
 985	 * board specific setup provides it as appropriate.  Systems where
 986	 * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 987	 * some almost-clones) can provide hooks to make that behave.
 988	 *
 989	 * Note that ACPI doesn't preclude putting these registers into
 990	 * "extended" areas of the chip, including some that we won't yet
 991	 * expect CMOS_READ and friends to handle.
 992	 */
 993	if (info) {
 994		if (info->flags)
 995			flags = info->flags;
 996		if (info->address_space)
 997			address_space = info->address_space;
 998
 999		cmos_rtc.day_alrm = info->rtc_day_alarm;
1000		cmos_rtc.mon_alrm = info->rtc_mon_alarm;
1001		cmos_rtc.century = info->rtc_century;
1002
1003		if (info->wake_on && info->wake_off) {
1004			cmos_rtc.wake_on = info->wake_on;
1005			cmos_rtc.wake_off = info->wake_off;
1006		}
1007	} else {
1008		acpi_cmos_wake_setup(dev);
1009	}
1010
1011	if (cmos_rtc.day_alrm >= 128)
1012		cmos_rtc.day_alrm = 0;
1013
1014	if (cmos_rtc.mon_alrm >= 128)
1015		cmos_rtc.mon_alrm = 0;
1016
1017	if (cmos_rtc.century >= 128)
1018		cmos_rtc.century = 0;
1019
1020	cmos_rtc.dev = dev;
1021	dev_set_drvdata(dev, &cmos_rtc);
1022
1023	cmos_rtc.rtc = devm_rtc_allocate_device(dev);
1024	if (IS_ERR(cmos_rtc.rtc)) {
1025		retval = PTR_ERR(cmos_rtc.rtc);
1026		goto cleanup0;
1027	}
1028
1029	if (cmos_rtc.mon_alrm)
1030		cmos_rtc.rtc->alarm_offset_max = SECS_PER_YEAR - 1;
1031	else if (cmos_rtc.day_alrm)
1032		cmos_rtc.rtc->alarm_offset_max = SECS_PER_MONTH - 1;
1033	else
1034		cmos_rtc.rtc->alarm_offset_max = SECS_PER_DAY - 1;
1035
1036	rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
1037
1038	if (!mc146818_does_rtc_work()) {
1039		dev_warn(dev, "broken or not accessible\n");
1040		retval = -ENXIO;
1041		goto cleanup1;
1042	}
1043
1044	spin_lock_irq(&rtc_lock);
1045
1046	if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
1047		/* force periodic irq to CMOS reset default of 1024Hz;
1048		 *
1049		 * REVISIT it's been reported that at least one x86_64 ALI
1050		 * mobo doesn't use 32KHz here ... for portability we might
1051		 * need to do something about other clock frequencies.
1052		 */
1053		cmos_rtc.rtc->irq_freq = 1024;
1054		if (use_hpet_alarm())
1055			hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
1056		CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
1057	}
1058
1059	/* disable irqs */
1060	if (is_valid_irq(rtc_irq))
1061		cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
1062
1063	rtc_control = CMOS_READ(RTC_CONTROL);
1064
1065	spin_unlock_irq(&rtc_lock);
1066
1067	if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
1068		dev_warn(dev, "only 24-hr supported\n");
1069		retval = -ENXIO;
1070		goto cleanup1;
1071	}
1072
1073	if (use_hpet_alarm())
1074		hpet_rtc_timer_init();
1075
1076	if (is_valid_irq(rtc_irq)) {
1077		irq_handler_t rtc_cmos_int_handler;
1078
1079		if (use_hpet_alarm()) {
1080			rtc_cmos_int_handler = hpet_rtc_interrupt;
1081			retval = hpet_register_irq_handler(cmos_interrupt);
1082			if (retval) {
1083				hpet_mask_rtc_irq_bit(RTC_IRQMASK);
1084				dev_warn(dev, "hpet_register_irq_handler "
1085						" failed in rtc_init().");
1086				goto cleanup1;
1087			}
1088		} else
1089			rtc_cmos_int_handler = cmos_interrupt;
1090
1091		retval = request_irq(rtc_irq, rtc_cmos_int_handler,
1092				0, dev_name(&cmos_rtc.rtc->dev),
1093				cmos_rtc.rtc);
1094		if (retval < 0) {
1095			dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
1096			goto cleanup1;
1097		}
1098	} else {
1099		clear_bit(RTC_FEATURE_ALARM, cmos_rtc.rtc->features);
1100	}
1101
1102	cmos_rtc.rtc->ops = &cmos_rtc_ops;
1103
1104	retval = devm_rtc_register_device(cmos_rtc.rtc);
1105	if (retval)
1106		goto cleanup2;
1107
1108	/* Set the sync offset for the periodic 11min update correct */
1109	cmos_rtc.rtc->set_offset_nsec = NSEC_PER_SEC / 2;
1110
1111	/* export at least the first block of NVRAM */
1112	nvmem_cfg.size = address_space - NVRAM_OFFSET;
1113	devm_rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg);
1114
1115	/*
1116	 * Everything has gone well so far, so by default register a handler for
1117	 * the ACPI RTC fixed event.
1118	 */
1119	if (!info)
1120		acpi_rtc_event_setup(dev);
1121
1122	dev_info(dev, "%s%s, %d bytes nvram%s\n",
1123		 !is_valid_irq(rtc_irq) ? "no alarms" :
1124		 cmos_rtc.mon_alrm ? "alarms up to one year" :
1125		 cmos_rtc.day_alrm ? "alarms up to one month" :
1126		 "alarms up to one day",
1127		 cmos_rtc.century ? ", y3k" : "",
1128		 nvmem_cfg.size,
1129		 use_hpet_alarm() ? ", hpet irqs" : "");
1130
1131	return 0;
1132
1133cleanup2:
1134	if (is_valid_irq(rtc_irq))
1135		free_irq(rtc_irq, cmos_rtc.rtc);
1136cleanup1:
1137	cmos_rtc.dev = NULL;
1138cleanup0:
1139	if (RTC_IOMAPPED)
1140		release_region(ports->start, resource_size(ports));
1141	else
1142		release_mem_region(ports->start, resource_size(ports));
1143	return retval;
1144}
1145
1146static void cmos_do_shutdown(int rtc_irq)
1147{
1148	spin_lock_irq(&rtc_lock);
1149	if (is_valid_irq(rtc_irq))
1150		cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
1151	spin_unlock_irq(&rtc_lock);
1152}
1153
1154static void cmos_do_remove(struct device *dev)
1155{
1156	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
1157	struct resource *ports;
1158
1159	cmos_do_shutdown(cmos->irq);
1160
1161	if (is_valid_irq(cmos->irq)) {
1162		free_irq(cmos->irq, cmos->rtc);
1163		if (use_hpet_alarm())
1164			hpet_unregister_irq_handler(cmos_interrupt);
1165	}
1166
1167	if (!dev_get_platdata(dev))
1168		acpi_rtc_event_cleanup();
1169
1170	cmos->rtc = NULL;
1171
1172	ports = cmos->iomem;
1173	if (RTC_IOMAPPED)
1174		release_region(ports->start, resource_size(ports));
1175	else
1176		release_mem_region(ports->start, resource_size(ports));
1177	cmos->iomem = NULL;
1178
1179	cmos->dev = NULL;
1180}
1181
1182static int cmos_aie_poweroff(struct device *dev)
1183{
1184	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
1185	struct rtc_time now;
1186	time64_t t_now;
1187	int retval = 0;
1188	unsigned char rtc_control;
1189
1190	if (!cmos->alarm_expires)
1191		return -EINVAL;
1192
1193	spin_lock_irq(&rtc_lock);
1194	rtc_control = CMOS_READ(RTC_CONTROL);
1195	spin_unlock_irq(&rtc_lock);
1196
1197	/* We only care about the situation where AIE is disabled. */
1198	if (rtc_control & RTC_AIE)
1199		return -EBUSY;
1200
1201	cmos_read_time(dev, &now);
1202	t_now = rtc_tm_to_time64(&now);
1203
1204	/*
1205	 * When enabling "RTC wake-up" in BIOS setup, the machine reboots
1206	 * automatically right after shutdown on some buggy boxes.
1207	 * This automatic rebooting issue won't happen when the alarm
1208	 * time is larger than now+1 seconds.
1209	 *
1210	 * If the alarm time is equal to now+1 seconds, the issue can be
1211	 * prevented by cancelling the alarm.
1212	 */
1213	if (cmos->alarm_expires == t_now + 1) {
1214		struct rtc_wkalrm alarm;
1215
1216		/* Cancel the AIE timer by configuring the past time. */
1217		rtc_time64_to_tm(t_now - 1, &alarm.time);
1218		alarm.enabled = 0;
1219		retval = cmos_set_alarm(dev, &alarm);
1220	} else if (cmos->alarm_expires > t_now + 1) {
1221		retval = -EBUSY;
1222	}
1223
1224	return retval;
1225}
1226
1227static int cmos_suspend(struct device *dev)
1228{
1229	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
1230	unsigned char	tmp;
1231
1232	/* only the alarm might be a wakeup event source */
1233	spin_lock_irq(&rtc_lock);
1234	cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
1235	if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
1236		unsigned char	mask;
1237
1238		if (device_may_wakeup(dev))
1239			mask = RTC_IRQMASK & ~RTC_AIE;
1240		else
1241			mask = RTC_IRQMASK;
1242		tmp &= ~mask;
1243		CMOS_WRITE(tmp, RTC_CONTROL);
1244		if (use_hpet_alarm())
1245			hpet_mask_rtc_irq_bit(mask);
1246		cmos_checkintr(cmos, tmp);
1247	}
1248	spin_unlock_irq(&rtc_lock);
1249
1250	if ((tmp & RTC_AIE) && !cmos_use_acpi_alarm()) {
1251		cmos->enabled_wake = 1;
1252		if (cmos->wake_on)
1253			cmos->wake_on(dev);
1254		else
1255			enable_irq_wake(cmos->irq);
1256	}
1257
1258	memset(&cmos->saved_wkalrm, 0, sizeof(struct rtc_wkalrm));
1259	cmos_read_alarm(dev, &cmos->saved_wkalrm);
1260
1261	dev_dbg(dev, "suspend%s, ctrl %02x\n",
1262			(tmp & RTC_AIE) ? ", alarm may wake" : "",
1263			tmp);
1264
1265	return 0;
1266}
1267
1268/* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
1269 * after a detour through G3 "mechanical off", although the ACPI spec
1270 * says wakeup should only work from G1/S4 "hibernate".  To most users,
1271 * distinctions between S4 and S5 are pointless.  So when the hardware
1272 * allows, don't draw that distinction.
1273 */
1274static inline int cmos_poweroff(struct device *dev)
1275{
1276	if (!IS_ENABLED(CONFIG_PM))
1277		return -ENOSYS;
1278
1279	return cmos_suspend(dev);
1280}
1281
1282static void cmos_check_wkalrm(struct device *dev)
1283{
1284	struct cmos_rtc *cmos = dev_get_drvdata(dev);
1285	struct rtc_wkalrm current_alarm;
1286	time64_t t_now;
1287	time64_t t_current_expires;
1288	time64_t t_saved_expires;
1289	struct rtc_time now;
1290
1291	/* Check if we have RTC Alarm armed */
1292	if (!(cmos->suspend_ctrl & RTC_AIE))
1293		return;
1294
1295	cmos_read_time(dev, &now);
1296	t_now = rtc_tm_to_time64(&now);
1297
1298	/*
1299	 * ACPI RTC wake event is cleared after resume from STR,
1300	 * ACK the rtc irq here
1301	 */
1302	if (t_now >= cmos->alarm_expires && cmos_use_acpi_alarm()) {
1303		local_irq_disable();
1304		cmos_interrupt(0, (void *)cmos->rtc);
1305		local_irq_enable();
1306		return;
1307	}
1308
1309	memset(&current_alarm, 0, sizeof(struct rtc_wkalrm));
1310	cmos_read_alarm(dev, &current_alarm);
1311	t_current_expires = rtc_tm_to_time64(&current_alarm.time);
1312	t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
1313	if (t_current_expires != t_saved_expires ||
1314	    cmos->saved_wkalrm.enabled != current_alarm.enabled) {
1315		cmos_set_alarm(dev, &cmos->saved_wkalrm);
1316	}
1317}
1318
1319static int __maybe_unused cmos_resume(struct device *dev)
1320{
1321	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
1322	unsigned char tmp;
1323
1324	if (cmos->enabled_wake && !cmos_use_acpi_alarm()) {
1325		if (cmos->wake_off)
1326			cmos->wake_off(dev);
1327		else
1328			disable_irq_wake(cmos->irq);
1329		cmos->enabled_wake = 0;
1330	}
1331
1332	/* The BIOS might have changed the alarm, restore it */
1333	cmos_check_wkalrm(dev);
1334
1335	spin_lock_irq(&rtc_lock);
1336	tmp = cmos->suspend_ctrl;
1337	cmos->suspend_ctrl = 0;
1338	/* re-enable any irqs previously active */
1339	if (tmp & RTC_IRQMASK) {
1340		unsigned char	mask;
1341
1342		if (device_may_wakeup(dev) && use_hpet_alarm())
1343			hpet_rtc_timer_init();
1344
1345		do {
1346			CMOS_WRITE(tmp, RTC_CONTROL);
1347			if (use_hpet_alarm())
1348				hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1349
1350			mask = CMOS_READ(RTC_INTR_FLAGS);
1351			mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1352			if (!use_hpet_alarm() || !is_intr(mask))
1353				break;
1354
1355			/* force one-shot behavior if HPET blocked
1356			 * the wake alarm's irq
1357			 */
1358			rtc_update_irq(cmos->rtc, 1, mask);
1359			tmp &= ~RTC_AIE;
1360			hpet_mask_rtc_irq_bit(RTC_AIE);
1361		} while (mask & RTC_AIE);
1362
1363		if (tmp & RTC_AIE)
1364			cmos_check_acpi_rtc_status(dev, &tmp);
1365	}
1366	spin_unlock_irq(&rtc_lock);
1367
1368	dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1369
1370	return 0;
1371}
1372
1373static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1374
1375/*----------------------------------------------------------------*/
1376
1377/* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1378 * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1379 * probably list them in similar PNPBIOS tables; so PNP is more common.
1380 *
1381 * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1382 * predate even PNPBIOS should set up platform_bus devices.
1383 */
1384
1385#ifdef	CONFIG_PNP
1386
1387#include <linux/pnp.h>
1388
1389static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1390{
1391	int irq;
1392
1393	if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1394		irq = 0;
1395#ifdef CONFIG_X86
1396		/* Some machines contain a PNP entry for the RTC, but
1397		 * don't define the IRQ. It should always be safe to
1398		 * hardcode it on systems with a legacy PIC.
1399		 */
1400		if (nr_legacy_irqs())
1401			irq = RTC_IRQ;
1402#endif
1403	} else {
1404		irq = pnp_irq(pnp, 0);
1405	}
1406
1407	return cmos_do_probe(&pnp->dev, pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1408}
1409
1410static void cmos_pnp_remove(struct pnp_dev *pnp)
1411{
1412	cmos_do_remove(&pnp->dev);
1413}
1414
1415static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1416{
1417	struct device *dev = &pnp->dev;
1418	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
1419
1420	if (system_state == SYSTEM_POWER_OFF) {
1421		int retval = cmos_poweroff(dev);
1422
1423		if (cmos_aie_poweroff(dev) < 0 && !retval)
1424			return;
1425	}
1426
1427	cmos_do_shutdown(cmos->irq);
1428}
1429
1430static const struct pnp_device_id rtc_ids[] = {
1431	{ .id = "PNP0b00", },
1432	{ .id = "PNP0b01", },
1433	{ .id = "PNP0b02", },
1434	{ },
1435};
1436MODULE_DEVICE_TABLE(pnp, rtc_ids);
1437
1438static struct pnp_driver cmos_pnp_driver = {
1439	.name		= driver_name,
1440	.id_table	= rtc_ids,
1441	.probe		= cmos_pnp_probe,
1442	.remove		= cmos_pnp_remove,
1443	.shutdown	= cmos_pnp_shutdown,
1444
1445	/* flag ensures resume() gets called, and stops syslog spam */
1446	.flags		= PNP_DRIVER_RES_DO_NOT_CHANGE,
1447	.driver		= {
1448			.pm = &cmos_pm_ops,
1449	},
1450};
1451
1452#endif	/* CONFIG_PNP */
1453
1454#ifdef CONFIG_OF
1455static const struct of_device_id of_cmos_match[] = {
1456	{
1457		.compatible = "motorola,mc146818",
1458	},
1459	{ },
1460};
1461MODULE_DEVICE_TABLE(of, of_cmos_match);
1462
1463static __init void cmos_of_init(struct platform_device *pdev)
1464{
1465	struct device_node *node = pdev->dev.of_node;
1466	const __be32 *val;
1467
1468	if (!node)
1469		return;
1470
1471	val = of_get_property(node, "ctrl-reg", NULL);
1472	if (val)
1473		CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1474
1475	val = of_get_property(node, "freq-reg", NULL);
1476	if (val)
1477		CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1478}
1479#else
1480static inline void cmos_of_init(struct platform_device *pdev) {}
1481#endif
1482/*----------------------------------------------------------------*/
1483
1484/* Platform setup should have set up an RTC device, when PNP is
1485 * unavailable ... this could happen even on (older) PCs.
1486 */
1487
1488static int __init cmos_platform_probe(struct platform_device *pdev)
1489{
1490	struct resource *resource;
1491	int irq;
1492
1493	cmos_of_init(pdev);
1494
1495	if (RTC_IOMAPPED)
1496		resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1497	else
1498		resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1499	irq = platform_get_irq(pdev, 0);
1500	if (irq < 0)
1501		irq = -1;
1502
1503	return cmos_do_probe(&pdev->dev, resource, irq);
1504}
1505
1506static void cmos_platform_remove(struct platform_device *pdev)
1507{
1508	cmos_do_remove(&pdev->dev);
 
1509}
1510
1511static void cmos_platform_shutdown(struct platform_device *pdev)
1512{
1513	struct device *dev = &pdev->dev;
1514	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
1515
1516	if (system_state == SYSTEM_POWER_OFF) {
1517		int retval = cmos_poweroff(dev);
1518
1519		if (cmos_aie_poweroff(dev) < 0 && !retval)
1520			return;
1521	}
1522
1523	cmos_do_shutdown(cmos->irq);
1524}
1525
1526/* work with hotplug and coldplug */
1527MODULE_ALIAS("platform:rtc_cmos");
1528
1529static struct platform_driver cmos_platform_driver = {
1530	.remove		= cmos_platform_remove,
1531	.shutdown	= cmos_platform_shutdown,
1532	.driver = {
1533		.name		= driver_name,
1534		.pm		= &cmos_pm_ops,
1535		.of_match_table = of_match_ptr(of_cmos_match),
1536	}
1537};
1538
1539#ifdef CONFIG_PNP
1540static bool pnp_driver_registered;
1541#endif
1542static bool platform_driver_registered;
1543
1544static int __init cmos_init(void)
1545{
1546	int retval = 0;
1547
1548#ifdef	CONFIG_PNP
1549	retval = pnp_register_driver(&cmos_pnp_driver);
1550	if (retval == 0)
1551		pnp_driver_registered = true;
1552#endif
1553
1554	if (!cmos_rtc.dev) {
1555		retval = platform_driver_probe(&cmos_platform_driver,
1556					       cmos_platform_probe);
1557		if (retval == 0)
1558			platform_driver_registered = true;
1559	}
1560
1561	if (retval == 0)
1562		return 0;
1563
1564#ifdef	CONFIG_PNP
1565	if (pnp_driver_registered)
1566		pnp_unregister_driver(&cmos_pnp_driver);
1567#endif
1568	return retval;
1569}
1570module_init(cmos_init);
1571
1572static void __exit cmos_exit(void)
1573{
1574#ifdef	CONFIG_PNP
1575	if (pnp_driver_registered)
1576		pnp_unregister_driver(&cmos_pnp_driver);
1577#endif
1578	if (platform_driver_registered)
1579		platform_driver_unregister(&cmos_platform_driver);
1580}
1581module_exit(cmos_exit);
1582
1583
1584MODULE_AUTHOR("David Brownell");
1585MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1586MODULE_LICENSE("GPL");