1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * RTC class driver for "CMOS RTC":  PCs, ACPI, etc
   4 *
   5 * Copyright (C) 1996 Paul Gortmaker (drivers/char/rtc.c)
   6 * Copyright (C) 2006 David Brownell (convert to new framework)
   7 */
   8
   9/*
  10 * The original "cmos clock" chip was an MC146818 chip, now obsolete.
  11 * That defined the register interface now provided by all PCs, some
  12 * non-PC systems, and incorporated into ACPI.  Modern PC chipsets
  13 * integrate an MC146818 clone in their southbridge, and boards use
  14 * that instead of discrete clones like the DS12887 or M48T86.  There
  15 * are also clones that connect using the LPC bus.
  16 *
  17 * That register API is also used directly by various other drivers
  18 * (notably for integrated NVRAM), infrastructure (x86 has code to
  19 * bypass the RTC framework, directly reading the RTC during boot
  20 * and updating minutes/seconds for systems using NTP synch) and
  21 * utilities (like userspace 'hwclock', if no /dev node exists).
  22 *
  23 * So **ALL** calls to CMOS_READ and CMOS_WRITE must be done with
  24 * interrupts disabled, holding the global rtc_lock, to exclude those
  25 * other drivers and utilities on correctly configured systems.
  26 */
  27
  28#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  29
  30#include <linux/kernel.h>
  31#include <linux/module.h>
  32#include <linux/init.h>
  33#include <linux/interrupt.h>
  34#include <linux/spinlock.h>
  35#include <linux/platform_device.h>
  36#include <linux/log2.h>
  37#include <linux/pm.h>
  38#include <linux/of.h>
  39#include <linux/of_platform.h>
  40#ifdef CONFIG_X86
  41#include <asm/i8259.h>
  42#include <asm/processor.h>
  43#include <linux/dmi.h>
  44#endif
  45
  46/* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
  47#include <linux/mc146818rtc.h>
  48
  49#ifdef CONFIG_ACPI
  50/*
  51 * Use ACPI SCI to replace HPET interrupt for RTC Alarm event
  52 *
  53 * If cleared, ACPI SCI is only used to wake up the system from suspend
  54 *
  55 * If set, ACPI SCI is used to handle UIE/AIE and system wakeup
  56 */
  57
  58static bool use_acpi_alarm;
  59module_param(use_acpi_alarm, bool, 0444);
  60
  61static inline int cmos_use_acpi_alarm(void)
  62{
  63	return use_acpi_alarm;
  64}
  65#else /* !CONFIG_ACPI */
  66
  67static inline int cmos_use_acpi_alarm(void)
  68{
  69	return 0;
  70}
  71#endif
  72
  73struct cmos_rtc {
  74	struct rtc_device	*rtc;
  75	struct device		*dev;
  76	int			irq;
  77	struct resource		*iomem;
  78	time64_t		alarm_expires;
  79
  80	void			(*wake_on)(struct device *);
  81	void			(*wake_off)(struct device *);
  82
  83	u8			enabled_wake;
  84	u8			suspend_ctrl;
  85
  86	/* newer hardware extends the original register set */
  87	u8			day_alrm;
  88	u8			mon_alrm;
  89	u8			century;
  90
  91	struct rtc_wkalrm	saved_wkalrm;
  92};
  93
  94/* both platform and pnp busses use negative numbers for invalid irqs */
  95#define is_valid_irq(n)		((n) > 0)
  96
  97static const char driver_name[] = "rtc_cmos";
  98
  99/* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
 100 * always mask it against the irq enable bits in RTC_CONTROL.  Bit values
 101 * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
 102 */
 103#define	RTC_IRQMASK	(RTC_PF | RTC_AF | RTC_UF)
 104
 105static inline int is_intr(u8 rtc_intr)
 106{
 107	if (!(rtc_intr & RTC_IRQF))
 108		return 0;
 109	return rtc_intr & RTC_IRQMASK;
 110}
 111
 112/*----------------------------------------------------------------*/
 113
 114/* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
 115 * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
 116 * used in a broken "legacy replacement" mode.  The breakage includes
 117 * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
 118 * other (better) use.
 119 *
 120 * When that broken mode is in use, platform glue provides a partial
 121 * emulation of hardware RTC IRQ facilities using HPET #1.  We don't
 122 * want to use HPET for anything except those IRQs though...
 123 */
 124#ifdef CONFIG_HPET_EMULATE_RTC
 125#include <asm/hpet.h>
 126#else
 127
 128static inline int is_hpet_enabled(void)
 129{
 130	return 0;
 131}
 132
 133static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
 134{
 135	return 0;
 136}
 137
 138static inline int hpet_set_rtc_irq_bit(unsigned long mask)
 139{
 140	return 0;
 141}
 142
 143static inline int
 144hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
 145{
 146	return 0;
 147}
 148
 149static inline int hpet_set_periodic_freq(unsigned long freq)
 150{
 151	return 0;
 152}
 153
 154static inline int hpet_rtc_dropped_irq(void)
 155{
 156	return 0;
 157}
 158
 159static inline int hpet_rtc_timer_init(void)
 160{
 161	return 0;
 162}
 163
 164extern irq_handler_t hpet_rtc_interrupt;
 165
 166static inline int hpet_register_irq_handler(irq_handler_t handler)
 167{
 168	return 0;
 169}
 170
 171static inline int hpet_unregister_irq_handler(irq_handler_t handler)
 172{
 173	return 0;
 174}
 175
 176#endif
 177
 178/* Don't use HPET for RTC Alarm event if ACPI Fixed event is used */
 179static inline int use_hpet_alarm(void)
 180{
 181	return is_hpet_enabled() && !cmos_use_acpi_alarm();
 182}
 183
 184/*----------------------------------------------------------------*/
 185
 186#ifdef RTC_PORT
 187
 188/* Most newer x86 systems have two register banks, the first used
 189 * for RTC and NVRAM and the second only for NVRAM.  Caller must
 190 * own rtc_lock ... and we won't worry about access during NMI.
 191 */
 192#define can_bank2	true
 193
 194static inline unsigned char cmos_read_bank2(unsigned char addr)
 195{
 196	outb(addr, RTC_PORT(2));
 197	return inb(RTC_PORT(3));
 198}
 199
 200static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 201{
 202	outb(addr, RTC_PORT(2));
 203	outb(val, RTC_PORT(3));
 204}
 205
 206#else
 207
 208#define can_bank2	false
 209
 210static inline unsigned char cmos_read_bank2(unsigned char addr)
 211{
 212	return 0;
 213}
 214
 215static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 216{
 217}
 218
 219#endif
 220
 221/*----------------------------------------------------------------*/
 222
 223static int cmos_read_time(struct device *dev, struct rtc_time *t)
 224{
 225	/*
 226	 * If pm_trace abused the RTC for storage, set the timespec to 0,
 227	 * which tells the caller that this RTC value is unusable.
 228	 */
 229	if (!pm_trace_rtc_valid())
 230		return -EIO;
 231
 232	/* REVISIT:  if the clock has a "century" register, use
 233	 * that instead of the heuristic in mc146818_get_time().
 234	 * That'll make Y3K compatility (year > 2070) easy!
 235	 */
 236	mc146818_get_time(t);
 237	return 0;
 238}
 239
 240static int cmos_set_time(struct device *dev, struct rtc_time *t)
 241{
 242	/* REVISIT:  set the "century" register if available
 243	 *
 244	 * NOTE: this ignores the issue whereby updating the seconds
 245	 * takes effect exactly 500ms after we write the register.
 246	 * (Also queueing and other delays before we get this far.)
 247	 */
 248	return mc146818_set_time(t);
 249}
 250
 251static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 252{
 253	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
 254	unsigned char	rtc_control;
 255
 256	/* This not only a rtc_op, but also called directly */
 257	if (!is_valid_irq(cmos->irq))
 258		return -EIO;
 259
 260	/* Basic alarms only support hour, minute, and seconds fields.
 261	 * Some also support day and month, for alarms up to a year in
 262	 * the future.
 263	 */
 264
 265	spin_lock_irq(&rtc_lock);
 266	t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
 267	t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
 268	t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 269
 270	if (cmos->day_alrm) {
 271		/* ignore upper bits on readback per ACPI spec */
 272		t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
 273		if (!t->time.tm_mday)
 274			t->time.tm_mday = -1;
 275
 276		if (cmos->mon_alrm) {
 277			t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
 278			if (!t->time.tm_mon)
 279				t->time.tm_mon = -1;
 280		}
 281	}
 282
 283	rtc_control = CMOS_READ(RTC_CONTROL);
 284	spin_unlock_irq(&rtc_lock);
 285
 286	if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 287		if (((unsigned)t->time.tm_sec) < 0x60)
 288			t->time.tm_sec = bcd2bin(t->time.tm_sec);
 289		else
 290			t->time.tm_sec = -1;
 291		if (((unsigned)t->time.tm_min) < 0x60)
 292			t->time.tm_min = bcd2bin(t->time.tm_min);
 293		else
 294			t->time.tm_min = -1;
 295		if (((unsigned)t->time.tm_hour) < 0x24)
 296			t->time.tm_hour = bcd2bin(t->time.tm_hour);
 297		else
 298			t->time.tm_hour = -1;
 299
 300		if (cmos->day_alrm) {
 301			if (((unsigned)t->time.tm_mday) <= 0x31)
 302				t->time.tm_mday = bcd2bin(t->time.tm_mday);
 303			else
 304				t->time.tm_mday = -1;
 305
 306			if (cmos->mon_alrm) {
 307				if (((unsigned)t->time.tm_mon) <= 0x12)
 308					t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
 309				else
 310					t->time.tm_mon = -1;
 311			}
 312		}
 313	}
 314
 315	t->enabled = !!(rtc_control & RTC_AIE);
 316	t->pending = 0;
 317
 318	return 0;
 319}
 320
 321static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
 322{
 323	unsigned char	rtc_intr;
 324
 325	/* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
 326	 * allegedly some older rtcs need that to handle irqs properly
 327	 */
 328	rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 329
 330	if (use_hpet_alarm())
 331		return;
 332
 333	rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 334	if (is_intr(rtc_intr))
 335		rtc_update_irq(cmos->rtc, 1, rtc_intr);
 336}
 337
 338static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
 339{
 340	unsigned char	rtc_control;
 341
 342	/* flush any pending IRQ status, notably for update irqs,
 343	 * before we enable new IRQs
 344	 */
 345	rtc_control = CMOS_READ(RTC_CONTROL);
 346	cmos_checkintr(cmos, rtc_control);
 347
 348	rtc_control |= mask;
 349	CMOS_WRITE(rtc_control, RTC_CONTROL);
 350	if (use_hpet_alarm())
 351		hpet_set_rtc_irq_bit(mask);
 352
 353	if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
 354		if (cmos->wake_on)
 355			cmos->wake_on(cmos->dev);
 356	}
 357
 358	cmos_checkintr(cmos, rtc_control);
 359}
 360
 361static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
 362{
 363	unsigned char	rtc_control;
 364
 365	rtc_control = CMOS_READ(RTC_CONTROL);
 366	rtc_control &= ~mask;
 367	CMOS_WRITE(rtc_control, RTC_CONTROL);
 368	if (use_hpet_alarm())
 369		hpet_mask_rtc_irq_bit(mask);
 370
 371	if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
 372		if (cmos->wake_off)
 373			cmos->wake_off(cmos->dev);
 374	}
 375
 376	cmos_checkintr(cmos, rtc_control);
 377}
 378
 379static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t)
 380{
 381	struct cmos_rtc *cmos = dev_get_drvdata(dev);
 382	struct rtc_time now;
 383
 384	cmos_read_time(dev, &now);
 385
 386	if (!cmos->day_alrm) {
 387		time64_t t_max_date;
 388		time64_t t_alrm;
 389
 390		t_max_date = rtc_tm_to_time64(&now);
 391		t_max_date += 24 * 60 * 60 - 1;
 392		t_alrm = rtc_tm_to_time64(&t->time);
 393		if (t_alrm > t_max_date) {
 394			dev_err(dev,
 395				"Alarms can be up to one day in the future\n");
 396			return -EINVAL;
 397		}
 398	} else if (!cmos->mon_alrm) {
 399		struct rtc_time max_date = now;
 400		time64_t t_max_date;
 401		time64_t t_alrm;
 402		int max_mday;
 403
 404		if (max_date.tm_mon == 11) {
 405			max_date.tm_mon = 0;
 406			max_date.tm_year += 1;
 407		} else {
 408			max_date.tm_mon += 1;
 409		}
 410		max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 411		if (max_date.tm_mday > max_mday)
 412			max_date.tm_mday = max_mday;
 413
 414		t_max_date = rtc_tm_to_time64(&max_date);
 415		t_max_date -= 1;
 416		t_alrm = rtc_tm_to_time64(&t->time);
 417		if (t_alrm > t_max_date) {
 418			dev_err(dev,
 419				"Alarms can be up to one month in the future\n");
 420			return -EINVAL;
 421		}
 422	} else {
 423		struct rtc_time max_date = now;
 424		time64_t t_max_date;
 425		time64_t t_alrm;
 426		int max_mday;
 427
 428		max_date.tm_year += 1;
 429		max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 430		if (max_date.tm_mday > max_mday)
 431			max_date.tm_mday = max_mday;
 432
 433		t_max_date = rtc_tm_to_time64(&max_date);
 434		t_max_date -= 1;
 435		t_alrm = rtc_tm_to_time64(&t->time);
 436		if (t_alrm > t_max_date) {
 437			dev_err(dev,
 438				"Alarms can be up to one year in the future\n");
 439			return -EINVAL;
 440		}
 441	}
 442
 443	return 0;
 444}
 445
 446static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 447{
 448	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
 449	unsigned char mon, mday, hrs, min, sec, rtc_control;
 450	int ret;
 451
 452	/* This not only a rtc_op, but also called directly */
 453	if (!is_valid_irq(cmos->irq))
 454		return -EIO;
 455
 456	ret = cmos_validate_alarm(dev, t);
 457	if (ret < 0)
 458		return ret;
 459
 460	mon = t->time.tm_mon + 1;
 461	mday = t->time.tm_mday;
 462	hrs = t->time.tm_hour;
 463	min = t->time.tm_min;
 464	sec = t->time.tm_sec;
 465
 466	rtc_control = CMOS_READ(RTC_CONTROL);
 467	if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 468		/* Writing 0xff means "don't care" or "match all".  */
 469		mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
 470		mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 471		hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
 472		min = (min < 60) ? bin2bcd(min) : 0xff;
 473		sec = (sec < 60) ? bin2bcd(sec) : 0xff;
 474	}
 475
 476	spin_lock_irq(&rtc_lock);
 477
 478	/* next rtc irq must not be from previous alarm setting */
 479	cmos_irq_disable(cmos, RTC_AIE);
 480
 481	/* update alarm */
 482	CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 483	CMOS_WRITE(min, RTC_MINUTES_ALARM);
 484	CMOS_WRITE(sec, RTC_SECONDS_ALARM);
 485
 486	/* the system may support an "enhanced" alarm */
 487	if (cmos->day_alrm) {
 488		CMOS_WRITE(mday, cmos->day_alrm);
 489		if (cmos->mon_alrm)
 490			CMOS_WRITE(mon, cmos->mon_alrm);
 491	}
 492
 493	if (use_hpet_alarm()) {
 494		/*
 495		 * FIXME the HPET alarm glue currently ignores day_alrm
 496		 * and mon_alrm ...
 497		 */
 498		hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min,
 499				    t->time.tm_sec);
 500	}
 501
 502	if (t->enabled)
 503		cmos_irq_enable(cmos, RTC_AIE);
 504
 505	spin_unlock_irq(&rtc_lock);
 506
 507	cmos->alarm_expires = rtc_tm_to_time64(&t->time);
 508
 509	return 0;
 510}
 511
 512static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 513{
 514	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
 515	unsigned long	flags;
 516
 517	spin_lock_irqsave(&rtc_lock, flags);
 518
 519	if (enabled)
 520		cmos_irq_enable(cmos, RTC_AIE);
 521	else
 522		cmos_irq_disable(cmos, RTC_AIE);
 523
 524	spin_unlock_irqrestore(&rtc_lock, flags);
 525	return 0;
 526}
 527
 528#if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 529
 530static int cmos_procfs(struct device *dev, struct seq_file *seq)
 531{
 532	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
 533	unsigned char	rtc_control, valid;
 534
 535	spin_lock_irq(&rtc_lock);
 536	rtc_control = CMOS_READ(RTC_CONTROL);
 537	valid = CMOS_READ(RTC_VALID);
 538	spin_unlock_irq(&rtc_lock);
 539
 540	/* NOTE:  at least ICH6 reports battery status using a different
 541	 * (non-RTC) bit; and SQWE is ignored on many current systems.
 542	 */
 543	seq_printf(seq,
 544		   "periodic_IRQ\t: %s\n"
 545		   "update_IRQ\t: %s\n"
 546		   "HPET_emulated\t: %s\n"
 547		   // "square_wave\t: %s\n"
 548		   "BCD\t\t: %s\n"
 549		   "DST_enable\t: %s\n"
 550		   "periodic_freq\t: %d\n"
 551		   "batt_status\t: %s\n",
 552		   (rtc_control & RTC_PIE) ? "yes" : "no",
 553		   (rtc_control & RTC_UIE) ? "yes" : "no",
 554		   use_hpet_alarm() ? "yes" : "no",
 555		   // (rtc_control & RTC_SQWE) ? "yes" : "no",
 556		   (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 557		   (rtc_control & RTC_DST_EN) ? "yes" : "no",
 558		   cmos->rtc->irq_freq,
 559		   (valid & RTC_VRT) ? "okay" : "dead");
 560
 561	return 0;
 562}
 563
 564#else
 565#define	cmos_procfs	NULL
 566#endif
 567
 568static const struct rtc_class_ops cmos_rtc_ops = {
 569	.read_time		= cmos_read_time,
 570	.set_time		= cmos_set_time,
 571	.read_alarm		= cmos_read_alarm,
 572	.set_alarm		= cmos_set_alarm,
 573	.proc			= cmos_procfs,
 574	.alarm_irq_enable	= cmos_alarm_irq_enable,
 575};
 576
 577static const struct rtc_class_ops cmos_rtc_ops_no_alarm = {
 578	.read_time		= cmos_read_time,
 579	.set_time		= cmos_set_time,
 580	.proc			= cmos_procfs,
 581};
 582
 583/*----------------------------------------------------------------*/
 584
 585/*
 586 * All these chips have at least 64 bytes of address space, shared by
 587 * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 588 * by boot firmware.  Modern chips have 128 or 256 bytes.
 589 */
 590
 591#define NVRAM_OFFSET	(RTC_REG_D + 1)
 592
 593static int cmos_nvram_read(void *priv, unsigned int off, void *val,
 594			   size_t count)
 595{
 596	unsigned char *buf = val;
 597	int	retval;
 598
 599	off += NVRAM_OFFSET;
 600	spin_lock_irq(&rtc_lock);
 601	for (retval = 0; count; count--, off++, retval++) {
 602		if (off < 128)
 603			*buf++ = CMOS_READ(off);
 604		else if (can_bank2)
 605			*buf++ = cmos_read_bank2(off);
 606		else
 607			break;
 608	}
 609	spin_unlock_irq(&rtc_lock);
 610
 611	return retval;
 612}
 613
 614static int cmos_nvram_write(void *priv, unsigned int off, void *val,
 615			    size_t count)
 616{
 617	struct cmos_rtc	*cmos = priv;
 618	unsigned char	*buf = val;
 619	int		retval;
 620
 621	/* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 622	 * checksum on part of the NVRAM data.  That's currently ignored
 623	 * here.  If userspace is smart enough to know what fields of
 624	 * NVRAM to update, updating checksums is also part of its job.
 625	 */
 626	off += NVRAM_OFFSET;
 627	spin_lock_irq(&rtc_lock);
 628	for (retval = 0; count; count--, off++, retval++) {
 629		/* don't trash RTC registers */
 630		if (off == cmos->day_alrm
 631				|| off == cmos->mon_alrm
 632				|| off == cmos->century)
 633			buf++;
 634		else if (off < 128)
 635			CMOS_WRITE(*buf++, off);
 636		else if (can_bank2)
 637			cmos_write_bank2(*buf++, off);
 638		else
 639			break;
 640	}
 641	spin_unlock_irq(&rtc_lock);
 642
 643	return retval;
 644}
 645
 646/*----------------------------------------------------------------*/
 647
 648static struct cmos_rtc	cmos_rtc;
 649
 650static irqreturn_t cmos_interrupt(int irq, void *p)
 651{
 652	unsigned long	flags;
 653	u8		irqstat;
 654	u8		rtc_control;
 655
 656	spin_lock_irqsave(&rtc_lock, flags);
 657
 658	/* When the HPET interrupt handler calls us, the interrupt
 659	 * status is passed as arg1 instead of the irq number.  But
 660	 * always clear irq status, even when HPET is in the way.
 661	 *
 662	 * Note that HPET and RTC are almost certainly out of phase,
 663	 * giving different IRQ status ...
 664	 */
 665	irqstat = CMOS_READ(RTC_INTR_FLAGS);
 666	rtc_control = CMOS_READ(RTC_CONTROL);
 667	if (use_hpet_alarm())
 668		irqstat = (unsigned long)irq & 0xF0;
 669
 670	/* If we were suspended, RTC_CONTROL may not be accurate since the
 671	 * bios may have cleared it.
 672	 */
 673	if (!cmos_rtc.suspend_ctrl)
 674		irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 675	else
 676		irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 677
 678	/* All Linux RTC alarms should be treated as if they were oneshot.
 679	 * Similar code may be needed in system wakeup paths, in case the
 680	 * alarm woke the system.
 681	 */
 682	if (irqstat & RTC_AIE) {
 683		cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 684		rtc_control &= ~RTC_AIE;
 685		CMOS_WRITE(rtc_control, RTC_CONTROL);
 686		if (use_hpet_alarm())
 687			hpet_mask_rtc_irq_bit(RTC_AIE);
 688		CMOS_READ(RTC_INTR_FLAGS);
 689	}
 690	spin_unlock_irqrestore(&rtc_lock, flags);
 691
 692	if (is_intr(irqstat)) {
 693		rtc_update_irq(p, 1, irqstat);
 694		return IRQ_HANDLED;
 695	} else
 696		return IRQ_NONE;
 697}
 698
 699#ifdef	CONFIG_PNP
 700#define	INITSECTION
 701
 702#else
 703#define	INITSECTION	__init
 704#endif
 705
 706static int INITSECTION
 707cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 708{
 709	struct cmos_rtc_board_info	*info = dev_get_platdata(dev);
 710	int				retval = 0;
 711	unsigned char			rtc_control;
 712	unsigned			address_space;
 713	u32				flags = 0;
 714	struct nvmem_config nvmem_cfg = {
 715		.name = "cmos_nvram",
 716		.word_size = 1,
 717		.stride = 1,
 718		.reg_read = cmos_nvram_read,
 719		.reg_write = cmos_nvram_write,
 720		.priv = &cmos_rtc,
 721	};
 722
 723	/* there can be only one ... */
 724	if (cmos_rtc.dev)
 725		return -EBUSY;
 726
 727	if (!ports)
 728		return -ENODEV;
 729
 730	/* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 731	 *
 732	 * REVISIT non-x86 systems may instead use memory space resources
 733	 * (needing ioremap etc), not i/o space resources like this ...
 734	 */
 735	if (RTC_IOMAPPED)
 736		ports = request_region(ports->start, resource_size(ports),
 737				       driver_name);
 738	else
 739		ports = request_mem_region(ports->start, resource_size(ports),
 740					   driver_name);
 741	if (!ports) {
 742		dev_dbg(dev, "i/o registers already in use\n");
 743		return -EBUSY;
 744	}
 745
 746	cmos_rtc.irq = rtc_irq;
 747	cmos_rtc.iomem = ports;
 748
 749	/* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 750	 * driver did, but don't reject unknown configs.   Old hardware
 751	 * won't address 128 bytes.  Newer chips have multiple banks,
 752	 * though they may not be listed in one I/O resource.
 753	 */
 754#if	defined(CONFIG_ATARI)
 755	address_space = 64;
 756#elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 757			|| defined(__sparc__) || defined(__mips__) \
 758			|| defined(__powerpc__)
 759	address_space = 128;
 760#else
 761#warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 762	address_space = 128;
 763#endif
 764	if (can_bank2 && ports->end > (ports->start + 1))
 765		address_space = 256;
 766
 767	/* For ACPI systems extension info comes from the FADT.  On others,
 768	 * board specific setup provides it as appropriate.  Systems where
 769	 * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 770	 * some almost-clones) can provide hooks to make that behave.
 771	 *
 772	 * Note that ACPI doesn't preclude putting these registers into
 773	 * "extended" areas of the chip, including some that we won't yet
 774	 * expect CMOS_READ and friends to handle.
 775	 */
 776	if (info) {
 777		if (info->flags)
 778			flags = info->flags;
 779		if (info->address_space)
 780			address_space = info->address_space;
 781
 782		if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
 783			cmos_rtc.day_alrm = info->rtc_day_alarm;
 784		if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
 785			cmos_rtc.mon_alrm = info->rtc_mon_alarm;
 786		if (info->rtc_century && info->rtc_century < 128)
 787			cmos_rtc.century = info->rtc_century;
 788
 789		if (info->wake_on && info->wake_off) {
 790			cmos_rtc.wake_on = info->wake_on;
 791			cmos_rtc.wake_off = info->wake_off;
 792		}
 793	}
 794
 795	cmos_rtc.dev = dev;
 796	dev_set_drvdata(dev, &cmos_rtc);
 797
 798	cmos_rtc.rtc = devm_rtc_allocate_device(dev);
 799	if (IS_ERR(cmos_rtc.rtc)) {
 800		retval = PTR_ERR(cmos_rtc.rtc);
 801		goto cleanup0;
 802	}
 803
 804	rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 805
 806	spin_lock_irq(&rtc_lock);
 807
 
 
 
 
 
 
 
 
 808	if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
 809		/* force periodic irq to CMOS reset default of 1024Hz;
 810		 *
 811		 * REVISIT it's been reported that at least one x86_64 ALI
 812		 * mobo doesn't use 32KHz here ... for portability we might
 813		 * need to do something about other clock frequencies.
 814		 */
 815		cmos_rtc.rtc->irq_freq = 1024;
 816		if (use_hpet_alarm())
 817			hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
 818		CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
 819	}
 820
 821	/* disable irqs */
 822	if (is_valid_irq(rtc_irq))
 823		cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
 824
 825	rtc_control = CMOS_READ(RTC_CONTROL);
 826
 827	spin_unlock_irq(&rtc_lock);
 828
 829	if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
 830		dev_warn(dev, "only 24-hr supported\n");
 831		retval = -ENXIO;
 832		goto cleanup1;
 833	}
 834
 835	if (use_hpet_alarm())
 836		hpet_rtc_timer_init();
 837
 838	if (is_valid_irq(rtc_irq)) {
 839		irq_handler_t rtc_cmos_int_handler;
 840
 841		if (use_hpet_alarm()) {
 842			rtc_cmos_int_handler = hpet_rtc_interrupt;
 843			retval = hpet_register_irq_handler(cmos_interrupt);
 844			if (retval) {
 845				hpet_mask_rtc_irq_bit(RTC_IRQMASK);
 846				dev_warn(dev, "hpet_register_irq_handler "
 847						" failed in rtc_init().");
 848				goto cleanup1;
 849			}
 850		} else
 851			rtc_cmos_int_handler = cmos_interrupt;
 852
 853		retval = request_irq(rtc_irq, rtc_cmos_int_handler,
 854				0, dev_name(&cmos_rtc.rtc->dev),
 855				cmos_rtc.rtc);
 856		if (retval < 0) {
 857			dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
 858			goto cleanup1;
 859		}
 860
 861		cmos_rtc.rtc->ops = &cmos_rtc_ops;
 862	} else {
 863		cmos_rtc.rtc->ops = &cmos_rtc_ops_no_alarm;
 864	}
 865
 866	cmos_rtc.rtc->nvram_old_abi = true;
 867	retval = rtc_register_device(cmos_rtc.rtc);
 
 868	if (retval)
 869		goto cleanup2;
 870
 
 
 
 871	/* export at least the first block of NVRAM */
 872	nvmem_cfg.size = address_space - NVRAM_OFFSET;
 873	if (rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg))
 874		dev_err(dev, "nvmem registration failed\n");
 875
 876	dev_info(dev, "%s%s, %d bytes nvram%s\n",
 877		 !is_valid_irq(rtc_irq) ? "no alarms" :
 878		 cmos_rtc.mon_alrm ? "alarms up to one year" :
 879		 cmos_rtc.day_alrm ? "alarms up to one month" :
 880		 "alarms up to one day",
 881		 cmos_rtc.century ? ", y3k" : "",
 882		 nvmem_cfg.size,
 883		 use_hpet_alarm() ? ", hpet irqs" : "");
 884
 885	return 0;
 886
 887cleanup2:
 888	if (is_valid_irq(rtc_irq))
 889		free_irq(rtc_irq, cmos_rtc.rtc);
 890cleanup1:
 891	cmos_rtc.dev = NULL;
 892cleanup0:
 893	if (RTC_IOMAPPED)
 894		release_region(ports->start, resource_size(ports));
 895	else
 896		release_mem_region(ports->start, resource_size(ports));
 897	return retval;
 898}
 899
 900static void cmos_do_shutdown(int rtc_irq)
 901{
 902	spin_lock_irq(&rtc_lock);
 903	if (is_valid_irq(rtc_irq))
 904		cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
 905	spin_unlock_irq(&rtc_lock);
 906}
 907
 908static void cmos_do_remove(struct device *dev)
 909{
 910	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
 911	struct resource *ports;
 912
 913	cmos_do_shutdown(cmos->irq);
 914
 915	if (is_valid_irq(cmos->irq)) {
 916		free_irq(cmos->irq, cmos->rtc);
 917		if (use_hpet_alarm())
 918			hpet_unregister_irq_handler(cmos_interrupt);
 919	}
 920
 921	cmos->rtc = NULL;
 922
 923	ports = cmos->iomem;
 924	if (RTC_IOMAPPED)
 925		release_region(ports->start, resource_size(ports));
 926	else
 927		release_mem_region(ports->start, resource_size(ports));
 928	cmos->iomem = NULL;
 929
 930	cmos->dev = NULL;
 931}
 932
 933static int cmos_aie_poweroff(struct device *dev)
 934{
 935	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
 936	struct rtc_time now;
 937	time64_t t_now;
 938	int retval = 0;
 939	unsigned char rtc_control;
 940
 941	if (!cmos->alarm_expires)
 942		return -EINVAL;
 943
 944	spin_lock_irq(&rtc_lock);
 945	rtc_control = CMOS_READ(RTC_CONTROL);
 946	spin_unlock_irq(&rtc_lock);
 947
 948	/* We only care about the situation where AIE is disabled. */
 949	if (rtc_control & RTC_AIE)
 950		return -EBUSY;
 951
 952	cmos_read_time(dev, &now);
 953	t_now = rtc_tm_to_time64(&now);
 954
 955	/*
 956	 * When enabling "RTC wake-up" in BIOS setup, the machine reboots
 957	 * automatically right after shutdown on some buggy boxes.
 958	 * This automatic rebooting issue won't happen when the alarm
 959	 * time is larger than now+1 seconds.
 960	 *
 961	 * If the alarm time is equal to now+1 seconds, the issue can be
 962	 * prevented by cancelling the alarm.
 963	 */
 964	if (cmos->alarm_expires == t_now + 1) {
 965		struct rtc_wkalrm alarm;
 966
 967		/* Cancel the AIE timer by configuring the past time. */
 968		rtc_time64_to_tm(t_now - 1, &alarm.time);
 969		alarm.enabled = 0;
 970		retval = cmos_set_alarm(dev, &alarm);
 971	} else if (cmos->alarm_expires > t_now + 1) {
 972		retval = -EBUSY;
 973	}
 974
 975	return retval;
 976}
 977
 978static int cmos_suspend(struct device *dev)
 979{
 980	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
 981	unsigned char	tmp;
 982
 983	/* only the alarm might be a wakeup event source */
 984	spin_lock_irq(&rtc_lock);
 985	cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
 986	if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 987		unsigned char	mask;
 988
 989		if (device_may_wakeup(dev))
 990			mask = RTC_IRQMASK & ~RTC_AIE;
 991		else
 992			mask = RTC_IRQMASK;
 993		tmp &= ~mask;
 994		CMOS_WRITE(tmp, RTC_CONTROL);
 995		if (use_hpet_alarm())
 996			hpet_mask_rtc_irq_bit(mask);
 997		cmos_checkintr(cmos, tmp);
 998	}
 999	spin_unlock_irq(&rtc_lock);
1000
1001	if ((tmp & RTC_AIE) && !cmos_use_acpi_alarm()) {
1002		cmos->enabled_wake = 1;
1003		if (cmos->wake_on)
1004			cmos->wake_on(dev);
1005		else
1006			enable_irq_wake(cmos->irq);
1007	}
1008
 
1009	cmos_read_alarm(dev, &cmos->saved_wkalrm);
1010
1011	dev_dbg(dev, "suspend%s, ctrl %02x\n",
1012			(tmp & RTC_AIE) ? ", alarm may wake" : "",
1013			tmp);
1014
1015	return 0;
1016}
1017
1018/* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
1019 * after a detour through G3 "mechanical off", although the ACPI spec
1020 * says wakeup should only work from G1/S4 "hibernate".  To most users,
1021 * distinctions between S4 and S5 are pointless.  So when the hardware
1022 * allows, don't draw that distinction.
1023 */
1024static inline int cmos_poweroff(struct device *dev)
1025{
1026	if (!IS_ENABLED(CONFIG_PM))
1027		return -ENOSYS;
1028
1029	return cmos_suspend(dev);
1030}
1031
1032static void cmos_check_wkalrm(struct device *dev)
1033{
1034	struct cmos_rtc *cmos = dev_get_drvdata(dev);
1035	struct rtc_wkalrm current_alarm;
1036	time64_t t_now;
1037	time64_t t_current_expires;
1038	time64_t t_saved_expires;
1039	struct rtc_time now;
1040
1041	/* Check if we have RTC Alarm armed */
1042	if (!(cmos->suspend_ctrl & RTC_AIE))
1043		return;
1044
1045	cmos_read_time(dev, &now);
1046	t_now = rtc_tm_to_time64(&now);
1047
1048	/*
1049	 * ACPI RTC wake event is cleared after resume from STR,
1050	 * ACK the rtc irq here
1051	 */
1052	if (t_now >= cmos->alarm_expires && cmos_use_acpi_alarm()) {
 
1053		cmos_interrupt(0, (void *)cmos->rtc);
 
1054		return;
1055	}
1056
 
1057	cmos_read_alarm(dev, &current_alarm);
1058	t_current_expires = rtc_tm_to_time64(&current_alarm.time);
1059	t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
1060	if (t_current_expires != t_saved_expires ||
1061	    cmos->saved_wkalrm.enabled != current_alarm.enabled) {
1062		cmos_set_alarm(dev, &cmos->saved_wkalrm);
1063	}
1064}
1065
1066static void cmos_check_acpi_rtc_status(struct device *dev,
1067				       unsigned char *rtc_control);
1068
1069static int __maybe_unused cmos_resume(struct device *dev)
1070{
1071	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
1072	unsigned char tmp;
1073
1074	if (cmos->enabled_wake && !cmos_use_acpi_alarm()) {
1075		if (cmos->wake_off)
1076			cmos->wake_off(dev);
1077		else
1078			disable_irq_wake(cmos->irq);
1079		cmos->enabled_wake = 0;
1080	}
1081
1082	/* The BIOS might have changed the alarm, restore it */
1083	cmos_check_wkalrm(dev);
1084
1085	spin_lock_irq(&rtc_lock);
1086	tmp = cmos->suspend_ctrl;
1087	cmos->suspend_ctrl = 0;
1088	/* re-enable any irqs previously active */
1089	if (tmp & RTC_IRQMASK) {
1090		unsigned char	mask;
1091
1092		if (device_may_wakeup(dev) && use_hpet_alarm())
1093			hpet_rtc_timer_init();
1094
1095		do {
1096			CMOS_WRITE(tmp, RTC_CONTROL);
1097			if (use_hpet_alarm())
1098				hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1099
1100			mask = CMOS_READ(RTC_INTR_FLAGS);
1101			mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1102			if (!use_hpet_alarm() || !is_intr(mask))
1103				break;
1104
1105			/* force one-shot behavior if HPET blocked
1106			 * the wake alarm's irq
1107			 */
1108			rtc_update_irq(cmos->rtc, 1, mask);
1109			tmp &= ~RTC_AIE;
1110			hpet_mask_rtc_irq_bit(RTC_AIE);
1111		} while (mask & RTC_AIE);
1112
1113		if (tmp & RTC_AIE)
1114			cmos_check_acpi_rtc_status(dev, &tmp);
1115	}
1116	spin_unlock_irq(&rtc_lock);
1117
1118	dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1119
1120	return 0;
1121}
1122
1123static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1124
1125/*----------------------------------------------------------------*/
1126
1127/* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1128 * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1129 * probably list them in similar PNPBIOS tables; so PNP is more common.
1130 *
1131 * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1132 * predate even PNPBIOS should set up platform_bus devices.
1133 */
1134
1135#ifdef	CONFIG_ACPI
1136
1137#include <linux/acpi.h>
1138
1139static u32 rtc_handler(void *context)
1140{
1141	struct device *dev = context;
1142	struct cmos_rtc *cmos = dev_get_drvdata(dev);
1143	unsigned char rtc_control = 0;
1144	unsigned char rtc_intr;
1145	unsigned long flags;
1146
1147
1148	/*
1149	 * Always update rtc irq when ACPI is used as RTC Alarm.
1150	 * Or else, ACPI SCI is enabled during suspend/resume only,
1151	 * update rtc irq in that case.
1152	 */
1153	if (cmos_use_acpi_alarm())
1154		cmos_interrupt(0, (void *)cmos->rtc);
1155	else {
1156		/* Fix me: can we use cmos_interrupt() here as well? */
1157		spin_lock_irqsave(&rtc_lock, flags);
1158		if (cmos_rtc.suspend_ctrl)
1159			rtc_control = CMOS_READ(RTC_CONTROL);
1160		if (rtc_control & RTC_AIE) {
1161			cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1162			CMOS_WRITE(rtc_control, RTC_CONTROL);
1163			rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1164			rtc_update_irq(cmos->rtc, 1, rtc_intr);
1165		}
1166		spin_unlock_irqrestore(&rtc_lock, flags);
1167	}
1168
1169	pm_wakeup_hard_event(dev);
1170	acpi_clear_event(ACPI_EVENT_RTC);
1171	acpi_disable_event(ACPI_EVENT_RTC, 0);
1172	return ACPI_INTERRUPT_HANDLED;
1173}
1174
1175static inline void rtc_wake_setup(struct device *dev)
1176{
1177	acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1178	/*
1179	 * After the RTC handler is installed, the Fixed_RTC event should
1180	 * be disabled. Only when the RTC alarm is set will it be enabled.
1181	 */
1182	acpi_clear_event(ACPI_EVENT_RTC);
1183	acpi_disable_event(ACPI_EVENT_RTC, 0);
1184}
1185
1186static void rtc_wake_on(struct device *dev)
1187{
1188	acpi_clear_event(ACPI_EVENT_RTC);
1189	acpi_enable_event(ACPI_EVENT_RTC, 0);
1190}
1191
1192static void rtc_wake_off(struct device *dev)
1193{
1194	acpi_disable_event(ACPI_EVENT_RTC, 0);
1195}
1196
1197#ifdef CONFIG_X86
1198/* Enable use_acpi_alarm mode for Intel platforms no earlier than 2015 */
1199static void use_acpi_alarm_quirks(void)
1200{
1201	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
1202		return;
1203
1204	if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
1205		return;
1206
1207	if (!is_hpet_enabled())
1208		return;
1209
1210	if (dmi_get_bios_year() < 2015)
1211		return;
1212
1213	use_acpi_alarm = true;
1214}
1215#else
1216static inline void use_acpi_alarm_quirks(void) { }
1217#endif
1218
1219/* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1220 * its device node and pass extra config data.  This helps its driver use
1221 * capabilities that the now-obsolete mc146818 didn't have, and informs it
1222 * that this board's RTC is wakeup-capable (per ACPI spec).
1223 */
1224static struct cmos_rtc_board_info acpi_rtc_info;
1225
1226static void cmos_wake_setup(struct device *dev)
1227{
1228	if (acpi_disabled)
1229		return;
1230
1231	use_acpi_alarm_quirks();
1232
1233	rtc_wake_setup(dev);
1234	acpi_rtc_info.wake_on = rtc_wake_on;
1235	acpi_rtc_info.wake_off = rtc_wake_off;
1236
1237	/* workaround bug in some ACPI tables */
1238	if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1239		dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1240			acpi_gbl_FADT.month_alarm);
1241		acpi_gbl_FADT.month_alarm = 0;
1242	}
1243
1244	acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1245	acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1246	acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1247
1248	/* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1249	if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1250		dev_info(dev, "RTC can wake from S4\n");
1251
1252	dev->platform_data = &acpi_rtc_info;
1253
1254	/* RTC always wakes from S1/S2/S3, and often S4/STD */
1255	device_init_wakeup(dev, 1);
1256}
1257
1258static void cmos_check_acpi_rtc_status(struct device *dev,
1259				       unsigned char *rtc_control)
1260{
1261	struct cmos_rtc *cmos = dev_get_drvdata(dev);
1262	acpi_event_status rtc_status;
1263	acpi_status status;
1264
1265	if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1266		return;
1267
1268	status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1269	if (ACPI_FAILURE(status)) {
1270		dev_err(dev, "Could not get RTC status\n");
1271	} else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1272		unsigned char mask;
1273		*rtc_control &= ~RTC_AIE;
1274		CMOS_WRITE(*rtc_control, RTC_CONTROL);
1275		mask = CMOS_READ(RTC_INTR_FLAGS);
1276		rtc_update_irq(cmos->rtc, 1, mask);
1277	}
1278}
1279
1280#else
1281
1282static void cmos_wake_setup(struct device *dev)
1283{
1284}
1285
1286static void cmos_check_acpi_rtc_status(struct device *dev,
1287				       unsigned char *rtc_control)
1288{
1289}
1290
1291#endif
1292
1293#ifdef	CONFIG_PNP
1294
1295#include <linux/pnp.h>
1296
1297static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1298{
1299	cmos_wake_setup(&pnp->dev);
1300
1301	if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1302		unsigned int irq = 0;
1303#ifdef CONFIG_X86
1304		/* Some machines contain a PNP entry for the RTC, but
1305		 * don't define the IRQ. It should always be safe to
1306		 * hardcode it on systems with a legacy PIC.
1307		 */
1308		if (nr_legacy_irqs())
1309			irq = RTC_IRQ;
1310#endif
1311		return cmos_do_probe(&pnp->dev,
1312				pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1313	} else {
1314		return cmos_do_probe(&pnp->dev,
1315				pnp_get_resource(pnp, IORESOURCE_IO, 0),
1316				pnp_irq(pnp, 0));
1317	}
1318}
1319
1320static void cmos_pnp_remove(struct pnp_dev *pnp)
1321{
1322	cmos_do_remove(&pnp->dev);
1323}
1324
1325static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1326{
1327	struct device *dev = &pnp->dev;
1328	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
1329
1330	if (system_state == SYSTEM_POWER_OFF) {
1331		int retval = cmos_poweroff(dev);
1332
1333		if (cmos_aie_poweroff(dev) < 0 && !retval)
1334			return;
1335	}
1336
1337	cmos_do_shutdown(cmos->irq);
1338}
1339
1340static const struct pnp_device_id rtc_ids[] = {
1341	{ .id = "PNP0b00", },
1342	{ .id = "PNP0b01", },
1343	{ .id = "PNP0b02", },
1344	{ },
1345};
1346MODULE_DEVICE_TABLE(pnp, rtc_ids);
1347
1348static struct pnp_driver cmos_pnp_driver = {
1349	.name		= driver_name,
1350	.id_table	= rtc_ids,
1351	.probe		= cmos_pnp_probe,
1352	.remove		= cmos_pnp_remove,
1353	.shutdown	= cmos_pnp_shutdown,
1354
1355	/* flag ensures resume() gets called, and stops syslog spam */
1356	.flags		= PNP_DRIVER_RES_DO_NOT_CHANGE,
1357	.driver		= {
1358			.pm = &cmos_pm_ops,
1359	},
1360};
1361
1362#endif	/* CONFIG_PNP */
1363
1364#ifdef CONFIG_OF
1365static const struct of_device_id of_cmos_match[] = {
1366	{
1367		.compatible = "motorola,mc146818",
1368	},
1369	{ },
1370};
1371MODULE_DEVICE_TABLE(of, of_cmos_match);
1372
1373static __init void cmos_of_init(struct platform_device *pdev)
1374{
1375	struct device_node *node = pdev->dev.of_node;
1376	const __be32 *val;
1377
1378	if (!node)
1379		return;
1380
1381	val = of_get_property(node, "ctrl-reg", NULL);
1382	if (val)
1383		CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1384
1385	val = of_get_property(node, "freq-reg", NULL);
1386	if (val)
1387		CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1388}
1389#else
1390static inline void cmos_of_init(struct platform_device *pdev) {}
1391#endif
1392/*----------------------------------------------------------------*/
1393
1394/* Platform setup should have set up an RTC device, when PNP is
1395 * unavailable ... this could happen even on (older) PCs.
1396 */
1397
1398static int __init cmos_platform_probe(struct platform_device *pdev)
1399{
1400	struct resource *resource;
1401	int irq;
1402
1403	cmos_of_init(pdev);
1404	cmos_wake_setup(&pdev->dev);
1405
1406	if (RTC_IOMAPPED)
1407		resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1408	else
1409		resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1410	irq = platform_get_irq(pdev, 0);
1411	if (irq < 0)
1412		irq = -1;
1413
1414	return cmos_do_probe(&pdev->dev, resource, irq);
1415}
1416
1417static int cmos_platform_remove(struct platform_device *pdev)
1418{
1419	cmos_do_remove(&pdev->dev);
1420	return 0;
1421}
1422
1423static void cmos_platform_shutdown(struct platform_device *pdev)
1424{
1425	struct device *dev = &pdev->dev;
1426	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
1427
1428	if (system_state == SYSTEM_POWER_OFF) {
1429		int retval = cmos_poweroff(dev);
1430
1431		if (cmos_aie_poweroff(dev) < 0 && !retval)
1432			return;
1433	}
1434
1435	cmos_do_shutdown(cmos->irq);
1436}
1437
1438/* work with hotplug and coldplug */
1439MODULE_ALIAS("platform:rtc_cmos");
1440
1441static struct platform_driver cmos_platform_driver = {
1442	.remove		= cmos_platform_remove,
1443	.shutdown	= cmos_platform_shutdown,
1444	.driver = {
1445		.name		= driver_name,
1446		.pm		= &cmos_pm_ops,
1447		.of_match_table = of_match_ptr(of_cmos_match),
1448	}
1449};
1450
1451#ifdef CONFIG_PNP
1452static bool pnp_driver_registered;
1453#endif
1454static bool platform_driver_registered;
1455
1456static int __init cmos_init(void)
1457{
1458	int retval = 0;
1459
1460#ifdef	CONFIG_PNP
1461	retval = pnp_register_driver(&cmos_pnp_driver);
1462	if (retval == 0)
1463		pnp_driver_registered = true;
1464#endif
1465
1466	if (!cmos_rtc.dev) {
1467		retval = platform_driver_probe(&cmos_platform_driver,
1468					       cmos_platform_probe);
1469		if (retval == 0)
1470			platform_driver_registered = true;
1471	}
1472
1473	if (retval == 0)
1474		return 0;
1475
1476#ifdef	CONFIG_PNP
1477	if (pnp_driver_registered)
1478		pnp_unregister_driver(&cmos_pnp_driver);
1479#endif
1480	return retval;
1481}
1482module_init(cmos_init);
1483
1484static void __exit cmos_exit(void)
1485{
1486#ifdef	CONFIG_PNP
1487	if (pnp_driver_registered)
1488		pnp_unregister_driver(&cmos_pnp_driver);
1489#endif
1490	if (platform_driver_registered)
1491		platform_driver_unregister(&cmos_platform_driver);
1492}
1493module_exit(cmos_exit);
1494
1495
1496MODULE_AUTHOR("David Brownell");
1497MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1498MODULE_LICENSE("GPL");