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         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
 512 static 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
 530 static 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
 568 static 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
 577 static 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
 593 static 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
 614 static 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
 648 static struct cmos_rtc  cmos_rtc;
 649
 650 static 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
 706 static int INITSECTION
 707 cmos_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         /* Set the sync offset for the periodic 11min update correct */
 872         cmos_rtc.rtc->set_offset_nsec = NSEC_PER_SEC / 2;
 873
 874         /* export at least the first block of NVRAM */
 875         nvmem_cfg.size = address_space - NVRAM_OFFSET;
 876         if (rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg))
 877                 dev_err(dev, "nvmem registration failed\n");
 878
 879         dev_info(dev, "%s%s, %d bytes nvram%s\n",
 880                  !is_valid_irq(rtc_irq) ? "no alarms" :
 881                  cmos_rtc.mon_alrm ? "alarms up to one year" :
 882                  cmos_rtc.day_alrm ? "alarms up to one month" :
 883                  "alarms up to one day",
 884                  cmos_rtc.century ? ", y3k" : "",
 885                  nvmem_cfg.size,
 886                  use_hpet_alarm() ? ", hpet irqs" : "");
 887
 888         return 0;
 889
 890 cleanup2:
 891         if (is_valid_irq(rtc_irq))
 892                 free_irq(rtc_irq, cmos_rtc.rtc);
 893 cleanup1:
 894         cmos_rtc.dev = NULL;
 895 cleanup0:
 896         if (RTC_IOMAPPED)
 897                 release_region(ports->start, resource_size(ports));
 898         else
 899                 release_mem_region(ports->start, resource_size(ports));
 900         return retval;
 901 }
 902
 903 static void cmos_do_shutdown(int rtc_irq)
 904 {
 905         spin_lock_irq(&rtc_lock);
 906         if (is_valid_irq(rtc_irq))
 907                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
 908         spin_unlock_irq(&rtc_lock);
 909 }
 910
 911 static void cmos_do_remove(struct device *dev)
 912 {
 913         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 914         struct resource *ports;
 915
 916         cmos_do_shutdown(cmos->irq);
 917
 918         if (is_valid_irq(cmos->irq)) {
 919                 free_irq(cmos->irq, cmos->rtc);
 920                 if (use_hpet_alarm())
 921                         hpet_unregister_irq_handler(cmos_interrupt);
 922         }
 923
 924         cmos->rtc = NULL;
 925
 926         ports = cmos->iomem;
 927         if (RTC_IOMAPPED)
 928                 release_region(ports->start, resource_size(ports));
 929         else
 930                 release_mem_region(ports->start, resource_size(ports));
 931         cmos->iomem = NULL;
 932
 933         cmos->dev = NULL;
 934 }
 935
 936 static int cmos_aie_poweroff(struct device *dev)
 937 {
 938         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 939         struct rtc_time now;
 940         time64_t t_now;
 941         int retval = 0;
 942         unsigned char rtc_control;
 943
 944         if (!cmos->alarm_expires)
 945                 return -EINVAL;
 946
 947         spin_lock_irq(&rtc_lock);
 948         rtc_control = CMOS_READ(RTC_CONTROL);
 949         spin_unlock_irq(&rtc_lock);
 950
 951         /* We only care about the situation where AIE is disabled. */
 952         if (rtc_control & RTC_AIE)
 953                 return -EBUSY;
 954
 955         cmos_read_time(dev, &now);
 956         t_now = rtc_tm_to_time64(&now);
 957
 958         /*
 959          * When enabling "RTC wake-up" in BIOS setup, the machine reboots
 960          * automatically right after shutdown on some buggy boxes.
 961          * This automatic rebooting issue won't happen when the alarm
 962          * time is larger than now+1 seconds.
 963          *
 964          * If the alarm time is equal to now+1 seconds, the issue can be
 965          * prevented by cancelling the alarm.
 966          */
 967         if (cmos->alarm_expires == t_now + 1) {
 968                 struct rtc_wkalrm alarm;
 969
 970                 /* Cancel the AIE timer by configuring the past time. */
 971                 rtc_time64_to_tm(t_now - 1, &alarm.time);
 972                 alarm.enabled = 0;
 973                 retval = cmos_set_alarm(dev, &alarm);
 974         } else if (cmos->alarm_expires > t_now + 1) {
 975                 retval = -EBUSY;
 976         }
 977
 978         return retval;
 979 }
 980
 981 static int cmos_suspend(struct device *dev)
 982 {
 983         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 984         unsigned char   tmp;
 985
 986         /* only the alarm might be a wakeup event source */
 987         spin_lock_irq(&rtc_lock);
 988         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
 989         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 990                 unsigned char   mask;
 991
 992                 if (device_may_wakeup(dev))
 993                         mask = RTC_IRQMASK & ~RTC_AIE;
 994                 else
 995                         mask = RTC_IRQMASK;
 996                 tmp &= ~mask;
 997                 CMOS_WRITE(tmp, RTC_CONTROL);
 998                 if (use_hpet_alarm())
 999                         hpet_mask_rtc_irq_bit(mask);
1000                 cmos_checkintr(cmos, tmp);
1001         }
1002         spin_unlock_irq(&rtc_lock);
1003
1004         if ((tmp & RTC_AIE) && !cmos_use_acpi_alarm()) {
1005                 cmos->enabled_wake = 1;
1006                 if (cmos->wake_on)
1007                         cmos->wake_on(dev);
1008                 else
1009                         enable_irq_wake(cmos->irq);
1010         }
1011
1012         memset(&cmos->saved_wkalrm, 0, sizeof(struct rtc_wkalrm));
1013         cmos_read_alarm(dev, &cmos->saved_wkalrm);
1014
1015         dev_dbg(dev, "suspend%s, ctrl %02x\n",
1016                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
1017                         tmp);
1018
1019         return 0;
1020 }
1021
1022 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
1023  * after a detour through G3 "mechanical off", although the ACPI spec
1024  * says wakeup should only work from G1/S4 "hibernate".  To most users,
1025  * distinctions between S4 and S5 are pointless.  So when the hardware
1026  * allows, don't draw that distinction.
1027  */
1028 static inline int cmos_poweroff(struct device *dev)
1029 {
1030         if (!IS_ENABLED(CONFIG_PM))
1031                 return -ENOSYS;
1032
1033         return cmos_suspend(dev);
1034 }
1035
1036 static void cmos_check_wkalrm(struct device *dev)
1037 {
1038         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1039         struct rtc_wkalrm current_alarm;
1040         time64_t t_now;
1041         time64_t t_current_expires;
1042         time64_t t_saved_expires;
1043         struct rtc_time now;
1044
1045         /* Check if we have RTC Alarm armed */
1046         if (!(cmos->suspend_ctrl & RTC_AIE))
1047                 return;
1048
1049         cmos_read_time(dev, &now);
1050         t_now = rtc_tm_to_time64(&now);
1051
1052         /*
1053          * ACPI RTC wake event is cleared after resume from STR,
1054          * ACK the rtc irq here
1055          */
1056         if (t_now >= cmos->alarm_expires && cmos_use_acpi_alarm()) {
1057                 cmos_interrupt(0, (void *)cmos->rtc);
1058                 return;
1059         }
1060
1061         memset(&current_alarm, 0, sizeof(struct rtc_wkalrm));
1062         cmos_read_alarm(dev, &current_alarm);
1063         t_current_expires = rtc_tm_to_time64(&current_alarm.time);
1064         t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
1065         if (t_current_expires != t_saved_expires ||
1066             cmos->saved_wkalrm.enabled != current_alarm.enabled) {
1067                 cmos_set_alarm(dev, &cmos->saved_wkalrm);
1068         }
1069 }
1070
1071 static void cmos_check_acpi_rtc_status(struct device *dev,
1072                                        unsigned char *rtc_control);
1073
1074 static int __maybe_unused cmos_resume(struct device *dev)
1075 {
1076         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1077         unsigned char tmp;
1078
1079         if (cmos->enabled_wake && !cmos_use_acpi_alarm()) {
1080                 if (cmos->wake_off)
1081                         cmos->wake_off(dev);
1082                 else
1083                         disable_irq_wake(cmos->irq);
1084                 cmos->enabled_wake = 0;
1085         }
1086
1087         /* The BIOS might have changed the alarm, restore it */
1088         cmos_check_wkalrm(dev);
1089
1090         spin_lock_irq(&rtc_lock);
1091         tmp = cmos->suspend_ctrl;
1092         cmos->suspend_ctrl = 0;
1093         /* re-enable any irqs previously active */
1094         if (tmp & RTC_IRQMASK) {
1095                 unsigned char   mask;
1096
1097                 if (device_may_wakeup(dev) && use_hpet_alarm())
1098                         hpet_rtc_timer_init();
1099
1100                 do {
1101                         CMOS_WRITE(tmp, RTC_CONTROL);
1102                         if (use_hpet_alarm())
1103                                 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1104
1105                         mask = CMOS_READ(RTC_INTR_FLAGS);
1106                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1107                         if (!use_hpet_alarm() || !is_intr(mask))
1108                                 break;
1109
1110                         /* force one-shot behavior if HPET blocked
1111                          * the wake alarm's irq
1112                          */
1113                         rtc_update_irq(cmos->rtc, 1, mask);
1114                         tmp &= ~RTC_AIE;
1115                         hpet_mask_rtc_irq_bit(RTC_AIE);
1116                 } while (mask & RTC_AIE);
1117
1118                 if (tmp & RTC_AIE)
1119                         cmos_check_acpi_rtc_status(dev, &tmp);
1120         }
1121         spin_unlock_irq(&rtc_lock);
1122
1123         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1124
1125         return 0;
1126 }
1127
1128 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1129
1130 /*----------------------------------------------------------------*/
1131
1132 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1133  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1134  * probably list them in similar PNPBIOS tables; so PNP is more common.
1135  *
1136  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1137  * predate even PNPBIOS should set up platform_bus devices.
1138  */
1139
1140 #ifdef  CONFIG_ACPI
1141
1142 #include <linux/acpi.h>
1143
1144 static u32 rtc_handler(void *context)
1145 {
1146         struct device *dev = context;
1147         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1148         unsigned char rtc_control = 0;
1149         unsigned char rtc_intr;
1150         unsigned long flags;
1151
1152
1153         /*
1154          * Always update rtc irq when ACPI is used as RTC Alarm.
1155          * Or else, ACPI SCI is enabled during suspend/resume only,
1156          * update rtc irq in that case.
1157          */
1158         if (cmos_use_acpi_alarm())
1159                 cmos_interrupt(0, (void *)cmos->rtc);
1160         else {
1161                 /* Fix me: can we use cmos_interrupt() here as well? */
1162                 spin_lock_irqsave(&rtc_lock, flags);
1163                 if (cmos_rtc.suspend_ctrl)
1164                         rtc_control = CMOS_READ(RTC_CONTROL);
1165                 if (rtc_control & RTC_AIE) {
1166                         cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1167                         CMOS_WRITE(rtc_control, RTC_CONTROL);
1168                         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1169                         rtc_update_irq(cmos->rtc, 1, rtc_intr);
1170                 }
1171                 spin_unlock_irqrestore(&rtc_lock, flags);
1172         }
1173
1174         pm_wakeup_hard_event(dev);
1175         acpi_clear_event(ACPI_EVENT_RTC);
1176         acpi_disable_event(ACPI_EVENT_RTC, 0);
1177         return ACPI_INTERRUPT_HANDLED;
1178 }
1179
1180 static inline void rtc_wake_setup(struct device *dev)
1181 {
1182         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1183         /*
1184          * After the RTC handler is installed, the Fixed_RTC event should
1185          * be disabled. Only when the RTC alarm is set will it be enabled.
1186          */
1187         acpi_clear_event(ACPI_EVENT_RTC);
1188         acpi_disable_event(ACPI_EVENT_RTC, 0);
1189 }
1190
1191 static void rtc_wake_on(struct device *dev)
1192 {
1193         acpi_clear_event(ACPI_EVENT_RTC);
1194         acpi_enable_event(ACPI_EVENT_RTC, 0);
1195 }
1196
1197 static void rtc_wake_off(struct device *dev)
1198 {
1199         acpi_disable_event(ACPI_EVENT_RTC, 0);
1200 }
1201
1202 #ifdef CONFIG_X86
1203 /* Enable use_acpi_alarm mode for Intel platforms no earlier than 2015 */
1204 static void use_acpi_alarm_quirks(void)
1205 {
1206         if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
1207                 return;
1208
1209         if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
1210                 return;
1211
1212         if (!is_hpet_enabled())
1213                 return;
1214
1215         if (dmi_get_bios_year() < 2015)
1216                 return;
1217
1218         use_acpi_alarm = true;
1219 }
1220 #else
1221 static inline void use_acpi_alarm_quirks(void) { }
1222 #endif
1223
1224 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1225  * its device node and pass extra config data.  This helps its driver use
1226  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1227  * that this board's RTC is wakeup-capable (per ACPI spec).
1228  */
1229 static struct cmos_rtc_board_info acpi_rtc_info;
1230
1231 static void cmos_wake_setup(struct device *dev)
1232 {
1233         if (acpi_disabled)
1234                 return;
1235
1236         use_acpi_alarm_quirks();
1237
1238         rtc_wake_setup(dev);
1239         acpi_rtc_info.wake_on = rtc_wake_on;
1240         acpi_rtc_info.wake_off = rtc_wake_off;
1241
1242         /* workaround bug in some ACPI tables */
1243         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1244                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1245                         acpi_gbl_FADT.month_alarm);
1246                 acpi_gbl_FADT.month_alarm = 0;
1247         }
1248
1249         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1250         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1251         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1252
1253         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1254         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1255                 dev_info(dev, "RTC can wake from S4\n");
1256
1257         dev->platform_data = &acpi_rtc_info;
1258
1259         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1260         device_init_wakeup(dev, 1);
1261 }
1262
1263 static void cmos_check_acpi_rtc_status(struct device *dev,
1264                                        unsigned char *rtc_control)
1265 {
1266         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1267         acpi_event_status rtc_status;
1268         acpi_status status;
1269
1270         if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1271                 return;
1272
1273         status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1274         if (ACPI_FAILURE(status)) {
1275                 dev_err(dev, "Could not get RTC status\n");
1276         } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1277                 unsigned char mask;
1278                 *rtc_control &= ~RTC_AIE;
1279                 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1280                 mask = CMOS_READ(RTC_INTR_FLAGS);
1281                 rtc_update_irq(cmos->rtc, 1, mask);
1282         }
1283 }
1284
1285 #else
1286
1287 static void cmos_wake_setup(struct device *dev)
1288 {
1289 }
1290
1291 static void cmos_check_acpi_rtc_status(struct device *dev,
1292                                        unsigned char *rtc_control)
1293 {
1294 }
1295
1296 #endif
1297
1298 #ifdef  CONFIG_PNP
1299
1300 #include <linux/pnp.h>
1301
1302 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1303 {
1304         cmos_wake_setup(&pnp->dev);
1305
1306         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1307                 unsigned int irq = 0;
1308 #ifdef CONFIG_X86
1309                 /* Some machines contain a PNP entry for the RTC, but
1310                  * don't define the IRQ. It should always be safe to
1311                  * hardcode it on systems with a legacy PIC.
1312                  */
1313                 if (nr_legacy_irqs())
1314                         irq = RTC_IRQ;
1315 #endif
1316                 return cmos_do_probe(&pnp->dev,
1317                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1318         } else {
1319                 return cmos_do_probe(&pnp->dev,
1320                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1321                                 pnp_irq(pnp, 0));
1322         }
1323 }
1324
1325 static void cmos_pnp_remove(struct pnp_dev *pnp)
1326 {
1327         cmos_do_remove(&pnp->dev);
1328 }
1329
1330 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1331 {
1332         struct device *dev = &pnp->dev;
1333         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1334
1335         if (system_state == SYSTEM_POWER_OFF) {
1336                 int retval = cmos_poweroff(dev);
1337
1338                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1339                         return;
1340         }
1341
1342         cmos_do_shutdown(cmos->irq);
1343 }
1344
1345 static const struct pnp_device_id rtc_ids[] = {
1346         { .id = "PNP0b00", },
1347         { .id = "PNP0b01", },
1348         { .id = "PNP0b02", },
1349         { },
1350 };
1351 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1352
1353 static struct pnp_driver cmos_pnp_driver = {
1354         .name           = driver_name,
1355         .id_table       = rtc_ids,
1356         .probe          = cmos_pnp_probe,
1357         .remove         = cmos_pnp_remove,
1358         .shutdown       = cmos_pnp_shutdown,
1359
1360         /* flag ensures resume() gets called, and stops syslog spam */
1361         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1362         .driver         = {
1363                         .pm = &cmos_pm_ops,
1364         },
1365 };
1366
1367 #endif  /* CONFIG_PNP */
1368
1369 #ifdef CONFIG_OF
1370 static const struct of_device_id of_cmos_match[] = {
1371         {
1372                 .compatible = "motorola,mc146818",
1373         },
1374         { },
1375 };
1376 MODULE_DEVICE_TABLE(of, of_cmos_match);
1377
1378 static __init void cmos_of_init(struct platform_device *pdev)
1379 {
1380         struct device_node *node = pdev->dev.of_node;
1381         const __be32 *val;
1382
1383         if (!node)
1384                 return;
1385
1386         val = of_get_property(node, "ctrl-reg", NULL);
1387         if (val)
1388                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1389
1390         val = of_get_property(node, "freq-reg", NULL);
1391         if (val)
1392                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1393 }
1394 #else
1395 static inline void cmos_of_init(struct platform_device *pdev) {}
1396 #endif
1397 /*----------------------------------------------------------------*/
1398
1399 /* Platform setup should have set up an RTC device, when PNP is
1400  * unavailable ... this could happen even on (older) PCs.
1401  */
1402
1403 static int __init cmos_platform_probe(struct platform_device *pdev)
1404 {
1405         struct resource *resource;
1406         int irq;
1407
1408         cmos_of_init(pdev);
1409         cmos_wake_setup(&pdev->dev);
1410
1411         if (RTC_IOMAPPED)
1412                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1413         else
1414                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1415         irq = platform_get_irq(pdev, 0);
1416         if (irq < 0)
1417                 irq = -1;
1418
1419         return cmos_do_probe(&pdev->dev, resource, irq);
1420 }
1421
1422 static int cmos_platform_remove(struct platform_device *pdev)
1423 {
1424         cmos_do_remove(&pdev->dev);
1425         return 0;
1426 }
1427
1428 static void cmos_platform_shutdown(struct platform_device *pdev)
1429 {
1430         struct device *dev = &pdev->dev;
1431         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1432
1433         if (system_state == SYSTEM_POWER_OFF) {
1434                 int retval = cmos_poweroff(dev);
1435
1436                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1437                         return;
1438         }
1439
1440         cmos_do_shutdown(cmos->irq);
1441 }
1442
1443 /* work with hotplug and coldplug */
1444 MODULE_ALIAS("platform:rtc_cmos");
1445
1446 static struct platform_driver cmos_platform_driver = {
1447         .remove         = cmos_platform_remove,
1448         .shutdown       = cmos_platform_shutdown,
1449         .driver = {
1450                 .name           = driver_name,
1451                 .pm             = &cmos_pm_ops,
1452                 .of_match_table = of_match_ptr(of_cmos_match),
1453         }
1454 };
1455
1456 #ifdef CONFIG_PNP
1457 static bool pnp_driver_registered;
1458 #endif
1459 static bool platform_driver_registered;
1460
1461 static int __init cmos_init(void)
1462 {
1463         int retval = 0;
1464
1465 #ifdef  CONFIG_PNP
1466         retval = pnp_register_driver(&cmos_pnp_driver);
1467         if (retval == 0)
1468                 pnp_driver_registered = true;
1469 #endif
1470
1471         if (!cmos_rtc.dev) {
1472                 retval = platform_driver_probe(&cmos_platform_driver,
1473                                                cmos_platform_probe);
1474                 if (retval == 0)
1475                         platform_driver_registered = true;
1476         }
1477
1478         if (retval == 0)
1479                 return 0;
1480
1481 #ifdef  CONFIG_PNP
1482         if (pnp_driver_registered)
1483                 pnp_unregister_driver(&cmos_pnp_driver);
1484 #endif
1485         return retval;
1486 }
1487 module_init(cmos_init);
1488
1489 static void __exit cmos_exit(void)
1490 {
1491 #ifdef  CONFIG_PNP
1492         if (pnp_driver_registered)
1493                 pnp_unregister_driver(&cmos_pnp_driver);
1494 #endif
1495         if (platform_driver_registered)
1496                 platform_driver_unregister(&cmos_platform_driver);
1497 }
1498 module_exit(cmos_exit);
1499
1500
1501 MODULE_AUTHOR("David Brownell");
1502 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1503 MODULE_LICENSE("GPL");