drivers/rtc/rtc-cmos.c

   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
  58 static bool use_acpi_alarm;
  59 module_param(use_acpi_alarm, bool, 0444);
  60
  61 static inline int cmos_use_acpi_alarm(void)
  62 {
  63         return use_acpi_alarm;
  64 }
  65 #else /* !CONFIG_ACPI */
  66
  67 static inline int cmos_use_acpi_alarm(void)
  68 {
  69         return 0;
  70 }
  71 #endif
  72
  73 struct 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
  97 static 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
 105 static 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
 128 static inline int is_hpet_enabled(void)
 129 {
 130         return 0;
 131 }
 132
 133 static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
 134 {
 135         return 0;
 136 }
 137
 138 static inline int hpet_set_rtc_irq_bit(unsigned long mask)
 139 {
 140         return 0;
 141 }
 142
 143 static inline int
 144 hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
 145 {
 146         return 0;
 147 }
 148
 149 static inline int hpet_set_periodic_freq(unsigned long freq)
 150 {
 151         return 0;
 152 }
 153
 154 static inline int hpet_rtc_dropped_irq(void)
 155 {
 156         return 0;
 157 }
 158
 159 static inline int hpet_rtc_timer_init(void)
 160 {
 161         return 0;
 162 }
 163
 164 extern irq_handler_t hpet_rtc_interrupt;
 165
 166 static inline int hpet_register_irq_handler(irq_handler_t handler)
 167 {
 168         return 0;
 169 }
 170
 171 static 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 */
 179 static 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
 194 static inline unsigned char cmos_read_bank2(unsigned char addr)
 195 {
 196         outb(addr, RTC_PORT(2));
 197         return inb(RTC_PORT(3));
 198 }
 199
 200 static 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
 210 static inline unsigned char cmos_read_bank2(unsigned char addr)
 211 {
 212         return 0;
 213 }
 214
 215 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 216 {
 217 }
 218
 219 #endif
 220
 221 /*----------------------------------------------------------------*/
 222
 223 static 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
 240 static 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
 251 static 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
 321 static 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
 338 static 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
 361 static 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
 379 static 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
 446 static 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         spin_lock_irq(&rtc_lock);
 467         rtc_control = CMOS_READ(RTC_CONTROL);
 468         spin_unlock_irq(&rtc_lock);
 469
 470         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 471                 /* Writing 0xff means "don't care" or "match all".  */
 472                 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
 473                 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 474                 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
 475                 min = (min < 60) ? bin2bcd(min) : 0xff;
 476                 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
 477         }
 478
 479         spin_lock_irq(&rtc_lock);
 480
 481         /* next rtc irq must not be from previous alarm setting */
 482         cmos_irq_disable(cmos, RTC_AIE);
 483
 484         /* update alarm */
 485         CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 486         CMOS_WRITE(min, RTC_MINUTES_ALARM);
 487         CMOS_WRITE(sec, RTC_SECONDS_ALARM);
 488
 489         /* the system may support an "enhanced" alarm */
 490         if (cmos->day_alrm) {
 491                 CMOS_WRITE(mday, cmos->day_alrm);
 492                 if (cmos->mon_alrm)
 493                         CMOS_WRITE(mon, cmos->mon_alrm);
 494         }
 495
 496         if (use_hpet_alarm()) {
 497                 /*
 498                  * FIXME the HPET alarm glue currently ignores day_alrm
 499                  * and mon_alrm ...
 500                  */
 501                 hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min,
 502                                     t->time.tm_sec);
 503         }
 504
 505         if (t->enabled)
 506                 cmos_irq_enable(cmos, RTC_AIE);
 507
 508         spin_unlock_irq(&rtc_lock);
 509
 510         cmos->alarm_expires = rtc_tm_to_time64(&t->time);
 511
 512         return 0;
 513 }
 514
 515 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 516 {
 517         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 518         unsigned long   flags;
 519
 520         spin_lock_irqsave(&rtc_lock, flags);
 521
 522         if (enabled)
 523                 cmos_irq_enable(cmos, RTC_AIE);
 524         else
 525                 cmos_irq_disable(cmos, RTC_AIE);
 526
 527         spin_unlock_irqrestore(&rtc_lock, flags);
 528         return 0;
 529 }
 530
 531 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 532
 533 static int cmos_procfs(struct device *dev, struct seq_file *seq)
 534 {
 535         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 536         unsigned char   rtc_control, valid;
 537
 538         spin_lock_irq(&rtc_lock);
 539         rtc_control = CMOS_READ(RTC_CONTROL);
 540         valid = CMOS_READ(RTC_VALID);
 541         spin_unlock_irq(&rtc_lock);
 542
 543         /* NOTE:  at least ICH6 reports battery status using a different
 544          * (non-RTC) bit; and SQWE is ignored on many current systems.
 545          */
 546         seq_printf(seq,
 547                    "periodic_IRQ\t: %s\n"
 548                    "update_IRQ\t: %s\n"
 549                    "HPET_emulated\t: %s\n"
 550                    // "square_wave\t: %s\n"
 551                    "BCD\t\t: %s\n"
 552                    "DST_enable\t: %s\n"
 553                    "periodic_freq\t: %d\n"
 554                    "batt_status\t: %s\n",
 555                    (rtc_control & RTC_PIE) ? "yes" : "no",
 556                    (rtc_control & RTC_UIE) ? "yes" : "no",
 557                    use_hpet_alarm() ? "yes" : "no",
 558                    // (rtc_control & RTC_SQWE) ? "yes" : "no",
 559                    (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 560                    (rtc_control & RTC_DST_EN) ? "yes" : "no",
 561                    cmos->rtc->irq_freq,
 562                    (valid & RTC_VRT) ? "okay" : "dead");
 563
 564         return 0;
 565 }
 566
 567 #else
 568 #define cmos_procfs     NULL
 569 #endif
 570
 571 static const struct rtc_class_ops cmos_rtc_ops = {
 572         .read_time              = cmos_read_time,
 573         .set_time               = cmos_set_time,
 574         .read_alarm             = cmos_read_alarm,
 575         .set_alarm              = cmos_set_alarm,
 576         .proc                   = cmos_procfs,
 577         .alarm_irq_enable       = cmos_alarm_irq_enable,
 578 };
 579
 580 static const struct rtc_class_ops cmos_rtc_ops_no_alarm = {
 581         .read_time              = cmos_read_time,
 582         .set_time               = cmos_set_time,
 583         .proc                   = cmos_procfs,
 584 };
 585
 586 /*----------------------------------------------------------------*/
 587
 588 /*
 589  * All these chips have at least 64 bytes of address space, shared by
 590  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 591  * by boot firmware.  Modern chips have 128 or 256 bytes.
 592  */
 593
 594 #define NVRAM_OFFSET    (RTC_REG_D + 1)
 595
 596 static int cmos_nvram_read(void *priv, unsigned int off, void *val,
 597                            size_t count)
 598 {
 599         unsigned char *buf = val;
 600         int     retval;
 601
 602         off += NVRAM_OFFSET;
 603         spin_lock_irq(&rtc_lock);
 604         for (retval = 0; count; count--, off++, retval++) {
 605                 if (off < 128)
 606                         *buf++ = CMOS_READ(off);
 607                 else if (can_bank2)
 608                         *buf++ = cmos_read_bank2(off);
 609                 else
 610                         break;
 611         }
 612         spin_unlock_irq(&rtc_lock);
 613
 614         return retval;
 615 }
 616
 617 static int cmos_nvram_write(void *priv, unsigned int off, void *val,
 618                             size_t count)
 619 {
 620         struct cmos_rtc *cmos = priv;
 621         unsigned char   *buf = val;
 622         int             retval;
 623
 624         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 625          * checksum on part of the NVRAM data.  That's currently ignored
 626          * here.  If userspace is smart enough to know what fields of
 627          * NVRAM to update, updating checksums is also part of its job.
 628          */
 629         off += NVRAM_OFFSET;
 630         spin_lock_irq(&rtc_lock);
 631         for (retval = 0; count; count--, off++, retval++) {
 632                 /* don't trash RTC registers */
 633                 if (off == cmos->day_alrm
 634                                 || off == cmos->mon_alrm
 635                                 || off == cmos->century)
 636                         buf++;
 637                 else if (off < 128)
 638                         CMOS_WRITE(*buf++, off);
 639                 else if (can_bank2)
 640                         cmos_write_bank2(*buf++, off);
 641                 else
 642                         break;
 643         }
 644         spin_unlock_irq(&rtc_lock);
 645
 646         return retval;
 647 }
 648
 649 /*----------------------------------------------------------------*/
 650
 651 static struct cmos_rtc  cmos_rtc;
 652
 653 static irqreturn_t cmos_interrupt(int irq, void *p)
 654 {
 655         u8              irqstat;
 656         u8              rtc_control;
 657
 658         spin_lock(&rtc_lock);
 659
 660         /* When the HPET interrupt handler calls us, the interrupt
 661          * status is passed as arg1 instead of the irq number.  But
 662          * always clear irq status, even when HPET is in the way.
 663          *
 664          * Note that HPET and RTC are almost certainly out of phase,
 665          * giving different IRQ status ...
 666          */
 667         irqstat = CMOS_READ(RTC_INTR_FLAGS);
 668         rtc_control = CMOS_READ(RTC_CONTROL);
 669         if (use_hpet_alarm())
 670                 irqstat = (unsigned long)irq & 0xF0;
 671
 672         /* If we were suspended, RTC_CONTROL may not be accurate since the
 673          * bios may have cleared it.
 674          */
 675         if (!cmos_rtc.suspend_ctrl)
 676                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 677         else
 678                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 679
 680         /* All Linux RTC alarms should be treated as if they were oneshot.
 681          * Similar code may be needed in system wakeup paths, in case the
 682          * alarm woke the system.
 683          */
 684         if (irqstat & RTC_AIE) {
 685                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 686                 rtc_control &= ~RTC_AIE;
 687                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 688                 if (use_hpet_alarm())
 689                         hpet_mask_rtc_irq_bit(RTC_AIE);
 690                 CMOS_READ(RTC_INTR_FLAGS);
 691         }
 692         spin_unlock(&rtc_lock);
 693
 694         if (is_intr(irqstat)) {
 695                 rtc_update_irq(p, 1, irqstat);
 696                 return IRQ_HANDLED;
 697         } else
 698                 return IRQ_NONE;
 699 }
 700
 701 #ifdef  CONFIG_PNP
 702 #define INITSECTION
 703
 704 #else
 705 #define INITSECTION     __init
 706 #endif
 707
 708 static int INITSECTION
 709 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 710 {
 711         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
 712         int                             retval = 0;
 713         unsigned char                   rtc_control;
 714         unsigned                        address_space;
 715         u32                             flags = 0;
 716         struct nvmem_config nvmem_cfg = {
 717                 .name = "cmos_nvram",
 718                 .word_size = 1,
 719                 .stride = 1,
 720                 .reg_read = cmos_nvram_read,
 721                 .reg_write = cmos_nvram_write,
 722                 .priv = &cmos_rtc,
 723         };
 724
 725         /* there can be only one ... */
 726         if (cmos_rtc.dev)
 727                 return -EBUSY;
 728
 729         if (!ports)
 730                 return -ENODEV;
 731
 732         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 733          *
 734          * REVISIT non-x86 systems may instead use memory space resources
 735          * (needing ioremap etc), not i/o space resources like this ...
 736          */
 737         if (RTC_IOMAPPED)
 738                 ports = request_region(ports->start, resource_size(ports),
 739                                        driver_name);
 740         else
 741                 ports = request_mem_region(ports->start, resource_size(ports),
 742                                            driver_name);
 743         if (!ports) {
 744                 dev_dbg(dev, "i/o registers already in use\n");
 745                 return -EBUSY;
 746         }
 747
 748         cmos_rtc.irq = rtc_irq;
 749         cmos_rtc.iomem = ports;
 750
 751         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 752          * driver did, but don't reject unknown configs.   Old hardware
 753          * won't address 128 bytes.  Newer chips have multiple banks,
 754          * though they may not be listed in one I/O resource.
 755          */
 756 #if     defined(CONFIG_ATARI)
 757         address_space = 64;
 758 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 759                         || defined(__sparc__) || defined(__mips__) \
 760                         || defined(__powerpc__)
 761         address_space = 128;
 762 #else
 763 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 764         address_space = 128;
 765 #endif
 766         if (can_bank2 && ports->end > (ports->start + 1))
 767                 address_space = 256;
 768
 769         /* For ACPI systems extension info comes from the FADT.  On others,
 770          * board specific setup provides it as appropriate.  Systems where
 771          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 772          * some almost-clones) can provide hooks to make that behave.
 773          *
 774          * Note that ACPI doesn't preclude putting these registers into
 775          * "extended" areas of the chip, including some that we won't yet
 776          * expect CMOS_READ and friends to handle.
 777          */
 778         if (info) {
 779                 if (info->flags)
 780                         flags = info->flags;
 781                 if (info->address_space)
 782                         address_space = info->address_space;
 783
 784                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
 785                         cmos_rtc.day_alrm = info->rtc_day_alarm;
 786                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
 787                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
 788                 if (info->rtc_century && info->rtc_century < 128)
 789                         cmos_rtc.century = info->rtc_century;
 790
 791                 if (info->wake_on && info->wake_off) {
 792                         cmos_rtc.wake_on = info->wake_on;
 793                         cmos_rtc.wake_off = info->wake_off;
 794                 }
 795         }
 796
 797         cmos_rtc.dev = dev;
 798         dev_set_drvdata(dev, &cmos_rtc);
 799
 800         cmos_rtc.rtc = devm_rtc_allocate_device(dev);
 801         if (IS_ERR(cmos_rtc.rtc)) {
 802                 retval = PTR_ERR(cmos_rtc.rtc);
 803                 goto cleanup0;
 804         }
 805
 806         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 807
 808         spin_lock_irq(&rtc_lock);
 809
 810         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
 811                 /* force periodic irq to CMOS reset default of 1024Hz;
 812                  *
 813                  * REVISIT it's been reported that at least one x86_64 ALI
 814                  * mobo doesn't use 32KHz here ... for portability we might
 815                  * need to do something about other clock frequencies.
 816                  */
 817                 cmos_rtc.rtc->irq_freq = 1024;
 818                 if (use_hpet_alarm())
 819                         hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
 820                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
 821         }
 822
 823         /* disable irqs */
 824         if (is_valid_irq(rtc_irq))
 825                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
 826
 827         rtc_control = CMOS_READ(RTC_CONTROL);
 828
 829         spin_unlock_irq(&rtc_lock);
 830
 831         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
 832                 dev_warn(dev, "only 24-hr supported\n");
 833                 retval = -ENXIO;
 834                 goto cleanup1;
 835         }
 836
 837         if (use_hpet_alarm())
 838                 hpet_rtc_timer_init();
 839
 840         if (is_valid_irq(rtc_irq)) {
 841                 irq_handler_t rtc_cmos_int_handler;
 842
 843                 if (use_hpet_alarm()) {
 844                         rtc_cmos_int_handler = hpet_rtc_interrupt;
 845                         retval = hpet_register_irq_handler(cmos_interrupt);
 846                         if (retval) {
 847                                 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
 848                                 dev_warn(dev, "hpet_register_irq_handler "
 849                                                 " failed in rtc_init().");
 850                                 goto cleanup1;
 851                         }
 852                 } else
 853                         rtc_cmos_int_handler = cmos_interrupt;
 854
 855                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
 856                                 0, dev_name(&cmos_rtc.rtc->dev),
 857                                 cmos_rtc.rtc);
 858                 if (retval < 0) {
 859                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
 860                         goto cleanup1;
 861                 }
 862
 863                 cmos_rtc.rtc->ops = &cmos_rtc_ops;
 864         } else {
 865                 cmos_rtc.rtc->ops = &cmos_rtc_ops_no_alarm;
 866         }
 867
 868         cmos_rtc.rtc->nvram_old_abi = true;
 869         retval = rtc_register_device(cmos_rtc.rtc);
 870         if (retval)
 871                 goto cleanup2;
 872
 873         /* export at least the first block of NVRAM */
 874         nvmem_cfg.size = address_space - NVRAM_OFFSET;
 875         if (rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg))
 876                 dev_err(dev, "nvmem registration failed\n");
 877
 878         dev_info(dev, "%s%s, %d bytes nvram%s\n",
 879                  !is_valid_irq(rtc_irq) ? "no alarms" :
 880                  cmos_rtc.mon_alrm ? "alarms up to one year" :
 881                  cmos_rtc.day_alrm ? "alarms up to one month" :
 882                  "alarms up to one day",
 883                  cmos_rtc.century ? ", y3k" : "",
 884                  nvmem_cfg.size,
 885                  use_hpet_alarm() ? ", hpet irqs" : "");
 886
 887         return 0;
 888
 889 cleanup2:
 890         if (is_valid_irq(rtc_irq))
 891                 free_irq(rtc_irq, cmos_rtc.rtc);
 892 cleanup1:
 893         cmos_rtc.dev = NULL;
 894 cleanup0:
 895         if (RTC_IOMAPPED)
 896                 release_region(ports->start, resource_size(ports));
 897         else
 898                 release_mem_region(ports->start, resource_size(ports));
 899         return retval;
 900 }
 901
 902 static void cmos_do_shutdown(int rtc_irq)
 903 {
 904         spin_lock_irq(&rtc_lock);
 905         if (is_valid_irq(rtc_irq))
 906                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
 907         spin_unlock_irq(&rtc_lock);
 908 }
 909
 910 static void cmos_do_remove(struct device *dev)
 911 {
 912         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 913         struct resource *ports;
 914
 915         cmos_do_shutdown(cmos->irq);
 916
 917         if (is_valid_irq(cmos->irq)) {
 918                 free_irq(cmos->irq, cmos->rtc);
 919                 if (use_hpet_alarm())
 920                         hpet_unregister_irq_handler(cmos_interrupt);
 921         }
 922
 923         cmos->rtc = NULL;
 924
 925         ports = cmos->iomem;
 926         if (RTC_IOMAPPED)
 927                 release_region(ports->start, resource_size(ports));
 928         else
 929                 release_mem_region(ports->start, resource_size(ports));
 930         cmos->iomem = NULL;
 931
 932         cmos->dev = NULL;
 933 }
 934
 935 static int cmos_aie_poweroff(struct device *dev)
 936 {
 937         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 938         struct rtc_time now;
 939         time64_t t_now;
 940         int retval = 0;
 941         unsigned char rtc_control;
 942
 943         if (!cmos->alarm_expires)
 944                 return -EINVAL;
 945
 946         spin_lock_irq(&rtc_lock);
 947         rtc_control = CMOS_READ(RTC_CONTROL);
 948         spin_unlock_irq(&rtc_lock);
 949
 950         /* We only care about the situation where AIE is disabled. */
 951         if (rtc_control & RTC_AIE)
 952                 return -EBUSY;
 953
 954         cmos_read_time(dev, &now);
 955         t_now = rtc_tm_to_time64(&now);
 956
 957         /*
 958          * When enabling "RTC wake-up" in BIOS setup, the machine reboots
 959          * automatically right after shutdown on some buggy boxes.
 960          * This automatic rebooting issue won't happen when the alarm
 961          * time is larger than now+1 seconds.
 962          *
 963          * If the alarm time is equal to now+1 seconds, the issue can be
 964          * prevented by cancelling the alarm.
 965          */
 966         if (cmos->alarm_expires == t_now + 1) {
 967                 struct rtc_wkalrm alarm;
 968
 969                 /* Cancel the AIE timer by configuring the past time. */
 970                 rtc_time64_to_tm(t_now - 1, &alarm.time);
 971                 alarm.enabled = 0;
 972                 retval = cmos_set_alarm(dev, &alarm);
 973         } else if (cmos->alarm_expires > t_now + 1) {
 974                 retval = -EBUSY;
 975         }
 976
 977         return retval;
 978 }
 979
 980 static int cmos_suspend(struct device *dev)
 981 {
 982         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 983         unsigned char   tmp;
 984
 985         /* only the alarm might be a wakeup event source */
 986         spin_lock_irq(&rtc_lock);
 987         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
 988         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 989                 unsigned char   mask;
 990
 991                 if (device_may_wakeup(dev))
 992                         mask = RTC_IRQMASK & ~RTC_AIE;
 993                 else
 994                         mask = RTC_IRQMASK;
 995                 tmp &= ~mask;
 996                 CMOS_WRITE(tmp, RTC_CONTROL);
 997                 if (use_hpet_alarm())
 998                         hpet_mask_rtc_irq_bit(mask);
 999                 cmos_checkintr(cmos, tmp);
1000         }
1001         spin_unlock_irq(&rtc_lock);
1002
1003         if ((tmp & RTC_AIE) && !cmos_use_acpi_alarm()) {
1004                 cmos->enabled_wake = 1;
1005                 if (cmos->wake_on)
1006                         cmos->wake_on(dev);
1007                 else
1008                         enable_irq_wake(cmos->irq);
1009         }
1010
1011         cmos_read_alarm(dev, &cmos->saved_wkalrm);
1012
1013         dev_dbg(dev, "suspend%s, ctrl %02x\n",
1014                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
1015                         tmp);
1016
1017         return 0;
1018 }
1019
1020 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
1021  * after a detour through G3 "mechanical off", although the ACPI spec
1022  * says wakeup should only work from G1/S4 "hibernate".  To most users,
1023  * distinctions between S4 and S5 are pointless.  So when the hardware
1024  * allows, don't draw that distinction.
1025  */
1026 static inline int cmos_poweroff(struct device *dev)
1027 {
1028         if (!IS_ENABLED(CONFIG_PM))
1029                 return -ENOSYS;
1030
1031         return cmos_suspend(dev);
1032 }
1033
1034 static void cmos_check_wkalrm(struct device *dev)
1035 {
1036         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1037         struct rtc_wkalrm current_alarm;
1038         time64_t t_now;
1039         time64_t t_current_expires;
1040         time64_t t_saved_expires;
1041         struct rtc_time now;
1042
1043         /* Check if we have RTC Alarm armed */
1044         if (!(cmos->suspend_ctrl & RTC_AIE))
1045                 return;
1046
1047         cmos_read_time(dev, &now);
1048         t_now = rtc_tm_to_time64(&now);
1049
1050         /*
1051          * ACPI RTC wake event is cleared after resume from STR,
1052          * ACK the rtc irq here
1053          */
1054         if (t_now >= cmos->alarm_expires && cmos_use_acpi_alarm()) {
1055                 cmos_interrupt(0, (void *)cmos->rtc);
1056                 return;
1057         }
1058
1059         cmos_read_alarm(dev, &current_alarm);
1060         t_current_expires = rtc_tm_to_time64(&current_alarm.time);
1061         t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
1062         if (t_current_expires != t_saved_expires ||
1063             cmos->saved_wkalrm.enabled != current_alarm.enabled) {
1064                 cmos_set_alarm(dev, &cmos->saved_wkalrm);
1065         }
1066 }
1067
1068 static void cmos_check_acpi_rtc_status(struct device *dev,
1069                                        unsigned char *rtc_control);
1070
1071 static int __maybe_unused cmos_resume(struct device *dev)
1072 {
1073         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1074         unsigned char tmp;
1075
1076         if (cmos->enabled_wake && !cmos_use_acpi_alarm()) {
1077                 if (cmos->wake_off)
1078                         cmos->wake_off(dev);
1079                 else
1080                         disable_irq_wake(cmos->irq);
1081                 cmos->enabled_wake = 0;
1082         }
1083
1084         /* The BIOS might have changed the alarm, restore it */
1085         cmos_check_wkalrm(dev);
1086
1087         spin_lock_irq(&rtc_lock);
1088         tmp = cmos->suspend_ctrl;
1089         cmos->suspend_ctrl = 0;
1090         /* re-enable any irqs previously active */
1091         if (tmp & RTC_IRQMASK) {
1092                 unsigned char   mask;
1093
1094                 if (device_may_wakeup(dev) && use_hpet_alarm())
1095                         hpet_rtc_timer_init();
1096
1097                 do {
1098                         CMOS_WRITE(tmp, RTC_CONTROL);
1099                         if (use_hpet_alarm())
1100                                 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1101
1102                         mask = CMOS_READ(RTC_INTR_FLAGS);
1103                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1104                         if (!use_hpet_alarm() || !is_intr(mask))
1105                                 break;
1106
1107                         /* force one-shot behavior if HPET blocked
1108                          * the wake alarm's irq
1109                          */
1110                         rtc_update_irq(cmos->rtc, 1, mask);
1111                         tmp &= ~RTC_AIE;
1112                         hpet_mask_rtc_irq_bit(RTC_AIE);
1113                 } while (mask & RTC_AIE);
1114
1115                 if (tmp & RTC_AIE)
1116                         cmos_check_acpi_rtc_status(dev, &tmp);
1117         }
1118         spin_unlock_irq(&rtc_lock);
1119
1120         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1121
1122         return 0;
1123 }
1124
1125 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1126
1127 /*----------------------------------------------------------------*/
1128
1129 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1130  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1131  * probably list them in similar PNPBIOS tables; so PNP is more common.
1132  *
1133  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1134  * predate even PNPBIOS should set up platform_bus devices.
1135  */
1136
1137 #ifdef  CONFIG_ACPI
1138
1139 #include <linux/acpi.h>
1140
1141 static u32 rtc_handler(void *context)
1142 {
1143         struct device *dev = context;
1144         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1145         unsigned char rtc_control = 0;
1146         unsigned char rtc_intr;
1147         unsigned long flags;
1148
1149
1150         /*
1151          * Always update rtc irq when ACPI is used as RTC Alarm.
1152          * Or else, ACPI SCI is enabled during suspend/resume only,
1153          * update rtc irq in that case.
1154          */
1155         if (cmos_use_acpi_alarm())
1156                 cmos_interrupt(0, (void *)cmos->rtc);
1157         else {
1158                 /* Fix me: can we use cmos_interrupt() here as well? */
1159                 spin_lock_irqsave(&rtc_lock, flags);
1160                 if (cmos_rtc.suspend_ctrl)
1161                         rtc_control = CMOS_READ(RTC_CONTROL);
1162                 if (rtc_control & RTC_AIE) {
1163                         cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1164                         CMOS_WRITE(rtc_control, RTC_CONTROL);
1165                         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1166                         rtc_update_irq(cmos->rtc, 1, rtc_intr);
1167                 }
1168                 spin_unlock_irqrestore(&rtc_lock, flags);
1169         }
1170
1171         pm_wakeup_hard_event(dev);
1172         acpi_clear_event(ACPI_EVENT_RTC);
1173         acpi_disable_event(ACPI_EVENT_RTC, 0);
1174         return ACPI_INTERRUPT_HANDLED;
1175 }
1176
1177 static inline void rtc_wake_setup(struct device *dev)
1178 {
1179         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1180         /*
1181          * After the RTC handler is installed, the Fixed_RTC event should
1182          * be disabled. Only when the RTC alarm is set will it be enabled.
1183          */
1184         acpi_clear_event(ACPI_EVENT_RTC);
1185         acpi_disable_event(ACPI_EVENT_RTC, 0);
1186 }
1187
1188 static void rtc_wake_on(struct device *dev)
1189 {
1190         acpi_clear_event(ACPI_EVENT_RTC);
1191         acpi_enable_event(ACPI_EVENT_RTC, 0);
1192 }
1193
1194 static void rtc_wake_off(struct device *dev)
1195 {
1196         acpi_disable_event(ACPI_EVENT_RTC, 0);
1197 }
1198
1199 #ifdef CONFIG_X86
1200 /* Enable use_acpi_alarm mode for Intel platforms no earlier than 2015 */
1201 static void use_acpi_alarm_quirks(void)
1202 {
1203         int year;
1204
1205         if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
1206                 return;
1207
1208         if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
1209                 return;
1210
1211         if (!is_hpet_enabled())
1212                 return;
1213
1214         if (dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL) && year >= 2015)
1215                 use_acpi_alarm = true;
1216 }
1217 #else
1218 static inline void use_acpi_alarm_quirks(void) { }
1219 #endif
1220
1221 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1222  * its device node and pass extra config data.  This helps its driver use
1223  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1224  * that this board's RTC is wakeup-capable (per ACPI spec).
1225  */
1226 static struct cmos_rtc_board_info acpi_rtc_info;
1227
1228 static void cmos_wake_setup(struct device *dev)
1229 {
1230         if (acpi_disabled)
1231                 return;
1232
1233         use_acpi_alarm_quirks();
1234
1235         rtc_wake_setup(dev);
1236         acpi_rtc_info.wake_on = rtc_wake_on;
1237         acpi_rtc_info.wake_off = rtc_wake_off;
1238
1239         /* workaround bug in some ACPI tables */
1240         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1241                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1242                         acpi_gbl_FADT.month_alarm);
1243                 acpi_gbl_FADT.month_alarm = 0;
1244         }
1245
1246         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1247         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1248         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1249
1250         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1251         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1252                 dev_info(dev, "RTC can wake from S4\n");
1253
1254         dev->platform_data = &acpi_rtc_info;
1255
1256         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1257         device_init_wakeup(dev, 1);
1258 }
1259
1260 static void cmos_check_acpi_rtc_status(struct device *dev,
1261                                        unsigned char *rtc_control)
1262 {
1263         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1264         acpi_event_status rtc_status;
1265         acpi_status status;
1266
1267         if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1268                 return;
1269
1270         status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1271         if (ACPI_FAILURE(status)) {
1272                 dev_err(dev, "Could not get RTC status\n");
1273         } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1274                 unsigned char mask;
1275                 *rtc_control &= ~RTC_AIE;
1276                 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1277                 mask = CMOS_READ(RTC_INTR_FLAGS);
1278                 rtc_update_irq(cmos->rtc, 1, mask);
1279         }
1280 }
1281
1282 #else
1283
1284 static void cmos_wake_setup(struct device *dev)
1285 {
1286 }
1287
1288 static void cmos_check_acpi_rtc_status(struct device *dev,
1289                                        unsigned char *rtc_control)
1290 {
1291 }
1292
1293 #endif
1294
1295 #ifdef  CONFIG_PNP
1296
1297 #include <linux/pnp.h>
1298
1299 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1300 {
1301         cmos_wake_setup(&pnp->dev);
1302
1303         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1304                 unsigned int irq = 0;
1305 #ifdef CONFIG_X86
1306                 /* Some machines contain a PNP entry for the RTC, but
1307                  * don't define the IRQ. It should always be safe to
1308                  * hardcode it on systems with a legacy PIC.
1309                  */
1310                 if (nr_legacy_irqs())
1311                         irq = 8;
1312 #endif
1313                 return cmos_do_probe(&pnp->dev,
1314                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1315         } else {
1316                 return cmos_do_probe(&pnp->dev,
1317                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1318                                 pnp_irq(pnp, 0));
1319         }
1320 }
1321
1322 static void cmos_pnp_remove(struct pnp_dev *pnp)
1323 {
1324         cmos_do_remove(&pnp->dev);
1325 }
1326
1327 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1328 {
1329         struct device *dev = &pnp->dev;
1330         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1331
1332         if (system_state == SYSTEM_POWER_OFF) {
1333                 int retval = cmos_poweroff(dev);
1334
1335                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1336                         return;
1337         }
1338
1339         cmos_do_shutdown(cmos->irq);
1340 }
1341
1342 static const struct pnp_device_id rtc_ids[] = {
1343         { .id = "PNP0b00", },
1344         { .id = "PNP0b01", },
1345         { .id = "PNP0b02", },
1346         { },
1347 };
1348 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1349
1350 static struct pnp_driver cmos_pnp_driver = {
1351         .name           = (char *) driver_name,
1352         .id_table       = rtc_ids,
1353         .probe          = cmos_pnp_probe,
1354         .remove         = cmos_pnp_remove,
1355         .shutdown       = cmos_pnp_shutdown,
1356
1357         /* flag ensures resume() gets called, and stops syslog spam */
1358         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1359         .driver         = {
1360                         .pm = &cmos_pm_ops,
1361         },
1362 };
1363
1364 #endif  /* CONFIG_PNP */
1365
1366 #ifdef CONFIG_OF
1367 static const struct of_device_id of_cmos_match[] = {
1368         {
1369                 .compatible = "motorola,mc146818",
1370         },
1371         { },
1372 };
1373 MODULE_DEVICE_TABLE(of, of_cmos_match);
1374
1375 static __init void cmos_of_init(struct platform_device *pdev)
1376 {
1377         struct device_node *node = pdev->dev.of_node;
1378         const __be32 *val;
1379
1380         if (!node)
1381                 return;
1382
1383         val = of_get_property(node, "ctrl-reg", NULL);
1384         if (val)
1385                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1386
1387         val = of_get_property(node, "freq-reg", NULL);
1388         if (val)
1389                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1390 }
1391 #else
1392 static inline void cmos_of_init(struct platform_device *pdev) {}
1393 #endif
1394 /*----------------------------------------------------------------*/
1395
1396 /* Platform setup should have set up an RTC device, when PNP is
1397  * unavailable ... this could happen even on (older) PCs.
1398  */
1399
1400 static int __init cmos_platform_probe(struct platform_device *pdev)
1401 {
1402         struct resource *resource;
1403         int irq;
1404
1405         cmos_of_init(pdev);
1406         cmos_wake_setup(&pdev->dev);
1407
1408         if (RTC_IOMAPPED)
1409                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1410         else
1411                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1412         irq = platform_get_irq(pdev, 0);
1413         if (irq < 0)
1414                 irq = -1;
1415
1416         return cmos_do_probe(&pdev->dev, resource, irq);
1417 }
1418
1419 static int cmos_platform_remove(struct platform_device *pdev)
1420 {
1421         cmos_do_remove(&pdev->dev);
1422         return 0;
1423 }
1424
1425 static void cmos_platform_shutdown(struct platform_device *pdev)
1426 {
1427         struct device *dev = &pdev->dev;
1428         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1429
1430         if (system_state == SYSTEM_POWER_OFF) {
1431                 int retval = cmos_poweroff(dev);
1432
1433                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1434                         return;
1435         }
1436
1437         cmos_do_shutdown(cmos->irq);
1438 }
1439
1440 /* work with hotplug and coldplug */
1441 MODULE_ALIAS("platform:rtc_cmos");
1442
1443 static struct platform_driver cmos_platform_driver = {
1444         .remove         = cmos_platform_remove,
1445         .shutdown       = cmos_platform_shutdown,
1446         .driver = {
1447                 .name           = driver_name,
1448                 .pm             = &cmos_pm_ops,
1449                 .of_match_table = of_match_ptr(of_cmos_match),
1450         }
1451 };
1452
1453 #ifdef CONFIG_PNP
1454 static bool pnp_driver_registered;
1455 #endif
1456 static bool platform_driver_registered;
1457
1458 static int __init cmos_init(void)
1459 {
1460         int retval = 0;
1461
1462 #ifdef  CONFIG_PNP
1463         retval = pnp_register_driver(&cmos_pnp_driver);
1464         if (retval == 0)
1465                 pnp_driver_registered = true;
1466 #endif
1467
1468         if (!cmos_rtc.dev) {
1469                 retval = platform_driver_probe(&cmos_platform_driver,
1470                                                cmos_platform_probe);
1471                 if (retval == 0)
1472                         platform_driver_registered = true;
1473         }
1474
1475         if (retval == 0)
1476                 return 0;
1477
1478 #ifdef  CONFIG_PNP
1479         if (pnp_driver_registered)
1480                 pnp_unregister_driver(&cmos_pnp_driver);
1481 #endif
1482         return retval;
1483 }
1484 module_init(cmos_init);
1485
1486 static void __exit cmos_exit(void)
1487 {
1488 #ifdef  CONFIG_PNP
1489         if (pnp_driver_registered)
1490                 pnp_unregister_driver(&cmos_pnp_driver);
1491 #endif
1492         if (platform_driver_registered)
1493                 platform_driver_unregister(&cmos_platform_driver);
1494 }
1495 module_exit(cmos_exit);
1496
1497
1498 MODULE_AUTHOR("David Brownell");
1499 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1500 MODULE_LICENSE("GPL");