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         retval = devm_rtc_register_device(cmos_rtc.rtc);
 867         if (retval)
 868                 goto cleanup2;
 869
 870         /* Set the sync offset for the periodic 11min update correct */
 871         cmos_rtc.rtc->set_offset_nsec = NSEC_PER_SEC / 2;
 872
 873         /* export at least the first block of NVRAM */
 874         nvmem_cfg.size = address_space - NVRAM_OFFSET;
 875         devm_rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg);
 876
 877         dev_info(dev, "%s%s, %d bytes nvram%s\n",
 878                  !is_valid_irq(rtc_irq) ? "no alarms" :
 879                  cmos_rtc.mon_alrm ? "alarms up to one year" :
 880                  cmos_rtc.day_alrm ? "alarms up to one month" :
 881                  "alarms up to one day",
 882                  cmos_rtc.century ? ", y3k" : "",
 883                  nvmem_cfg.size,
 884                  use_hpet_alarm() ? ", hpet irqs" : "");
 885
 886         return 0;
 887
 888 cleanup2:
 889         if (is_valid_irq(rtc_irq))
 890                 free_irq(rtc_irq, cmos_rtc.rtc);
 891 cleanup1:
 892         cmos_rtc.dev = NULL;
 893 cleanup0:
 894         if (RTC_IOMAPPED)
 895                 release_region(ports->start, resource_size(ports));
 896         else
 897                 release_mem_region(ports->start, resource_size(ports));
 898         return retval;
 899 }
 900
 901 static void cmos_do_shutdown(int rtc_irq)
 902 {
 903         spin_lock_irq(&rtc_lock);
 904         if (is_valid_irq(rtc_irq))
 905                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
 906         spin_unlock_irq(&rtc_lock);
 907 }
 908
 909 static void cmos_do_remove(struct device *dev)
 910 {
 911         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 912         struct resource *ports;
 913
 914         cmos_do_shutdown(cmos->irq);
 915
 916         if (is_valid_irq(cmos->irq)) {
 917                 free_irq(cmos->irq, cmos->rtc);
 918                 if (use_hpet_alarm())
 919                         hpet_unregister_irq_handler(cmos_interrupt);
 920         }
 921
 922         cmos->rtc = NULL;
 923
 924         ports = cmos->iomem;
 925         if (RTC_IOMAPPED)
 926                 release_region(ports->start, resource_size(ports));
 927         else
 928                 release_mem_region(ports->start, resource_size(ports));
 929         cmos->iomem = NULL;
 930
 931         cmos->dev = NULL;
 932 }
 933
 934 static int cmos_aie_poweroff(struct device *dev)
 935 {
 936         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 937         struct rtc_time now;
 938         time64_t t_now;
 939         int retval = 0;
 940         unsigned char rtc_control;
 941
 942         if (!cmos->alarm_expires)
 943                 return -EINVAL;
 944
 945         spin_lock_irq(&rtc_lock);
 946         rtc_control = CMOS_READ(RTC_CONTROL);
 947         spin_unlock_irq(&rtc_lock);
 948
 949         /* We only care about the situation where AIE is disabled. */
 950         if (rtc_control & RTC_AIE)
 951                 return -EBUSY;
 952
 953         cmos_read_time(dev, &now);
 954         t_now = rtc_tm_to_time64(&now);
 955
 956         /*
 957          * When enabling "RTC wake-up" in BIOS setup, the machine reboots
 958          * automatically right after shutdown on some buggy boxes.
 959          * This automatic rebooting issue won't happen when the alarm
 960          * time is larger than now+1 seconds.
 961          *
 962          * If the alarm time is equal to now+1 seconds, the issue can be
 963          * prevented by cancelling the alarm.
 964          */
 965         if (cmos->alarm_expires == t_now + 1) {
 966                 struct rtc_wkalrm alarm;
 967
 968                 /* Cancel the AIE timer by configuring the past time. */
 969                 rtc_time64_to_tm(t_now - 1, &alarm.time);
 970                 alarm.enabled = 0;
 971                 retval = cmos_set_alarm(dev, &alarm);
 972         } else if (cmos->alarm_expires > t_now + 1) {
 973                 retval = -EBUSY;
 974         }
 975
 976         return retval;
 977 }
 978
 979 static int cmos_suspend(struct device *dev)
 980 {
 981         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 982         unsigned char   tmp;
 983
 984         /* only the alarm might be a wakeup event source */
 985         spin_lock_irq(&rtc_lock);
 986         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
 987         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 988                 unsigned char   mask;
 989
 990                 if (device_may_wakeup(dev))
 991                         mask = RTC_IRQMASK & ~RTC_AIE;
 992                 else
 993                         mask = RTC_IRQMASK;
 994                 tmp &= ~mask;
 995                 CMOS_WRITE(tmp, RTC_CONTROL);
 996                 if (use_hpet_alarm())
 997                         hpet_mask_rtc_irq_bit(mask);
 998                 cmos_checkintr(cmos, tmp);
 999         }
1000         spin_unlock_irq(&rtc_lock);
1001
1002         if ((tmp & RTC_AIE) && !cmos_use_acpi_alarm()) {
1003                 cmos->enabled_wake = 1;
1004                 if (cmos->wake_on)
1005                         cmos->wake_on(dev);
1006                 else
1007                         enable_irq_wake(cmos->irq);
1008         }
1009
1010         memset(&cmos->saved_wkalrm, 0, sizeof(struct rtc_wkalrm));
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         memset(&current_alarm, 0, sizeof(struct rtc_wkalrm));
1060         cmos_read_alarm(dev, &current_alarm);
1061         t_current_expires = rtc_tm_to_time64(&current_alarm.time);
1062         t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
1063         if (t_current_expires != t_saved_expires ||
1064             cmos->saved_wkalrm.enabled != current_alarm.enabled) {
1065                 cmos_set_alarm(dev, &cmos->saved_wkalrm);
1066         }
1067 }
1068
1069 static void cmos_check_acpi_rtc_status(struct device *dev,
1070                                        unsigned char *rtc_control);
1071
1072 static int __maybe_unused cmos_resume(struct device *dev)
1073 {
1074         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1075         unsigned char tmp;
1076
1077         if (cmos->enabled_wake && !cmos_use_acpi_alarm()) {
1078                 if (cmos->wake_off)
1079                         cmos->wake_off(dev);
1080                 else
1081                         disable_irq_wake(cmos->irq);
1082                 cmos->enabled_wake = 0;
1083         }
1084
1085         /* The BIOS might have changed the alarm, restore it */
1086         cmos_check_wkalrm(dev);
1087
1088         spin_lock_irq(&rtc_lock);
1089         tmp = cmos->suspend_ctrl;
1090         cmos->suspend_ctrl = 0;
1091         /* re-enable any irqs previously active */
1092         if (tmp & RTC_IRQMASK) {
1093                 unsigned char   mask;
1094
1095                 if (device_may_wakeup(dev) && use_hpet_alarm())
1096                         hpet_rtc_timer_init();
1097
1098                 do {
1099                         CMOS_WRITE(tmp, RTC_CONTROL);
1100                         if (use_hpet_alarm())
1101                                 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1102
1103                         mask = CMOS_READ(RTC_INTR_FLAGS);
1104                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1105                         if (!use_hpet_alarm() || !is_intr(mask))
1106                                 break;
1107
1108                         /* force one-shot behavior if HPET blocked
1109                          * the wake alarm's irq
1110                          */
1111                         rtc_update_irq(cmos->rtc, 1, mask);
1112                         tmp &= ~RTC_AIE;
1113                         hpet_mask_rtc_irq_bit(RTC_AIE);
1114                 } while (mask & RTC_AIE);
1115
1116                 if (tmp & RTC_AIE)
1117                         cmos_check_acpi_rtc_status(dev, &tmp);
1118         }
1119         spin_unlock_irq(&rtc_lock);
1120
1121         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1122
1123         return 0;
1124 }
1125
1126 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1127
1128 /*----------------------------------------------------------------*/
1129
1130 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1131  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1132  * probably list them in similar PNPBIOS tables; so PNP is more common.
1133  *
1134  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1135  * predate even PNPBIOS should set up platform_bus devices.
1136  */
1137
1138 #ifdef  CONFIG_ACPI
1139
1140 #include <linux/acpi.h>
1141
1142 static u32 rtc_handler(void *context)
1143 {
1144         struct device *dev = context;
1145         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1146         unsigned char rtc_control = 0;
1147         unsigned char rtc_intr;
1148         unsigned long flags;
1149
1150
1151         /*
1152          * Always update rtc irq when ACPI is used as RTC Alarm.
1153          * Or else, ACPI SCI is enabled during suspend/resume only,
1154          * update rtc irq in that case.
1155          */
1156         if (cmos_use_acpi_alarm())
1157                 cmos_interrupt(0, (void *)cmos->rtc);
1158         else {
1159                 /* Fix me: can we use cmos_interrupt() here as well? */
1160                 spin_lock_irqsave(&rtc_lock, flags);
1161                 if (cmos_rtc.suspend_ctrl)
1162                         rtc_control = CMOS_READ(RTC_CONTROL);
1163                 if (rtc_control & RTC_AIE) {
1164                         cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1165                         CMOS_WRITE(rtc_control, RTC_CONTROL);
1166                         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1167                         rtc_update_irq(cmos->rtc, 1, rtc_intr);
1168                 }
1169                 spin_unlock_irqrestore(&rtc_lock, flags);
1170         }
1171
1172         pm_wakeup_hard_event(dev);
1173         acpi_clear_event(ACPI_EVENT_RTC);
1174         acpi_disable_event(ACPI_EVENT_RTC, 0);
1175         return ACPI_INTERRUPT_HANDLED;
1176 }
1177
1178 static inline void rtc_wake_setup(struct device *dev)
1179 {
1180         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1181         /*
1182          * After the RTC handler is installed, the Fixed_RTC event should
1183          * be disabled. Only when the RTC alarm is set will it be enabled.
1184          */
1185         acpi_clear_event(ACPI_EVENT_RTC);
1186         acpi_disable_event(ACPI_EVENT_RTC, 0);
1187 }
1188
1189 static void rtc_wake_on(struct device *dev)
1190 {
1191         acpi_clear_event(ACPI_EVENT_RTC);
1192         acpi_enable_event(ACPI_EVENT_RTC, 0);
1193 }
1194
1195 static void rtc_wake_off(struct device *dev)
1196 {
1197         acpi_disable_event(ACPI_EVENT_RTC, 0);
1198 }
1199
1200 #ifdef CONFIG_X86
1201 /* Enable use_acpi_alarm mode for Intel platforms no earlier than 2015 */
1202 static void use_acpi_alarm_quirks(void)
1203 {
1204         if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
1205                 return;
1206
1207         if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
1208                 return;
1209
1210         if (!is_hpet_enabled())
1211                 return;
1212
1213         if (dmi_get_bios_year() < 2015)
1214                 return;
1215
1216         use_acpi_alarm = true;
1217 }
1218 #else
1219 static inline void use_acpi_alarm_quirks(void) { }
1220 #endif
1221
1222 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1223  * its device node and pass extra config data.  This helps its driver use
1224  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1225  * that this board's RTC is wakeup-capable (per ACPI spec).
1226  */
1227 static struct cmos_rtc_board_info acpi_rtc_info;
1228
1229 static void cmos_wake_setup(struct device *dev)
1230 {
1231         if (acpi_disabled)
1232                 return;
1233
1234         use_acpi_alarm_quirks();
1235
1236         rtc_wake_setup(dev);
1237         acpi_rtc_info.wake_on = rtc_wake_on;
1238         acpi_rtc_info.wake_off = rtc_wake_off;
1239
1240         /* workaround bug in some ACPI tables */
1241         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1242                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1243                         acpi_gbl_FADT.month_alarm);
1244                 acpi_gbl_FADT.month_alarm = 0;
1245         }
1246
1247         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1248         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1249         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1250
1251         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1252         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1253                 dev_info(dev, "RTC can wake from S4\n");
1254
1255         dev->platform_data = &acpi_rtc_info;
1256
1257         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1258         device_init_wakeup(dev, 1);
1259 }
1260
1261 static void cmos_check_acpi_rtc_status(struct device *dev,
1262                                        unsigned char *rtc_control)
1263 {
1264         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1265         acpi_event_status rtc_status;
1266         acpi_status status;
1267
1268         if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1269                 return;
1270
1271         status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1272         if (ACPI_FAILURE(status)) {
1273                 dev_err(dev, "Could not get RTC status\n");
1274         } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1275                 unsigned char mask;
1276                 *rtc_control &= ~RTC_AIE;
1277                 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1278                 mask = CMOS_READ(RTC_INTR_FLAGS);
1279                 rtc_update_irq(cmos->rtc, 1, mask);
1280         }
1281 }
1282
1283 #else
1284
1285 static void cmos_wake_setup(struct device *dev)
1286 {
1287 }
1288
1289 static void cmos_check_acpi_rtc_status(struct device *dev,
1290                                        unsigned char *rtc_control)
1291 {
1292 }
1293
1294 #endif
1295
1296 #ifdef  CONFIG_PNP
1297
1298 #include <linux/pnp.h>
1299
1300 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1301 {
1302         cmos_wake_setup(&pnp->dev);
1303
1304         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1305                 unsigned int irq = 0;
1306 #ifdef CONFIG_X86
1307                 /* Some machines contain a PNP entry for the RTC, but
1308                  * don't define the IRQ. It should always be safe to
1309                  * hardcode it on systems with a legacy PIC.
1310                  */
1311                 if (nr_legacy_irqs())
1312                         irq = RTC_IRQ;
1313 #endif
1314                 return cmos_do_probe(&pnp->dev,
1315                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1316         } else {
1317                 return cmos_do_probe(&pnp->dev,
1318                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1319                                 pnp_irq(pnp, 0));
1320         }
1321 }
1322
1323 static void cmos_pnp_remove(struct pnp_dev *pnp)
1324 {
1325         cmos_do_remove(&pnp->dev);
1326 }
1327
1328 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1329 {
1330         struct device *dev = &pnp->dev;
1331         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1332
1333         if (system_state == SYSTEM_POWER_OFF) {
1334                 int retval = cmos_poweroff(dev);
1335
1336                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1337                         return;
1338         }
1339
1340         cmos_do_shutdown(cmos->irq);
1341 }
1342
1343 static const struct pnp_device_id rtc_ids[] = {
1344         { .id = "PNP0b00", },
1345         { .id = "PNP0b01", },
1346         { .id = "PNP0b02", },
1347         { },
1348 };
1349 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1350
1351 static struct pnp_driver cmos_pnp_driver = {
1352         .name           = driver_name,
1353         .id_table       = rtc_ids,
1354         .probe          = cmos_pnp_probe,
1355         .remove         = cmos_pnp_remove,
1356         .shutdown       = cmos_pnp_shutdown,
1357
1358         /* flag ensures resume() gets called, and stops syslog spam */
1359         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1360         .driver         = {
1361                         .pm = &cmos_pm_ops,
1362         },
1363 };
1364
1365 #endif  /* CONFIG_PNP */
1366
1367 #ifdef CONFIG_OF
1368 static const struct of_device_id of_cmos_match[] = {
1369         {
1370                 .compatible = "motorola,mc146818",
1371         },
1372         { },
1373 };
1374 MODULE_DEVICE_TABLE(of, of_cmos_match);
1375
1376 static __init void cmos_of_init(struct platform_device *pdev)
1377 {
1378         struct device_node *node = pdev->dev.of_node;
1379         const __be32 *val;
1380
1381         if (!node)
1382                 return;
1383
1384         val = of_get_property(node, "ctrl-reg", NULL);
1385         if (val)
1386                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1387
1388         val = of_get_property(node, "freq-reg", NULL);
1389         if (val)
1390                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1391 }
1392 #else
1393 static inline void cmos_of_init(struct platform_device *pdev) {}
1394 #endif
1395 /*----------------------------------------------------------------*/
1396
1397 /* Platform setup should have set up an RTC device, when PNP is
1398  * unavailable ... this could happen even on (older) PCs.
1399  */
1400
1401 static int __init cmos_platform_probe(struct platform_device *pdev)
1402 {
1403         struct resource *resource;
1404         int irq;
1405
1406         cmos_of_init(pdev);
1407         cmos_wake_setup(&pdev->dev);
1408
1409         if (RTC_IOMAPPED)
1410                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1411         else
1412                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1413         irq = platform_get_irq(pdev, 0);
1414         if (irq < 0)
1415                 irq = -1;
1416
1417         return cmos_do_probe(&pdev->dev, resource, irq);
1418 }
1419
1420 static int cmos_platform_remove(struct platform_device *pdev)
1421 {
1422         cmos_do_remove(&pdev->dev);
1423         return 0;
1424 }
1425
1426 static void cmos_platform_shutdown(struct platform_device *pdev)
1427 {
1428         struct device *dev = &pdev->dev;
1429         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1430
1431         if (system_state == SYSTEM_POWER_OFF) {
1432                 int retval = cmos_poweroff(dev);
1433
1434                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1435                         return;
1436         }
1437
1438         cmos_do_shutdown(cmos->irq);
1439 }
1440
1441 /* work with hotplug and coldplug */
1442 MODULE_ALIAS("platform:rtc_cmos");
1443
1444 static struct platform_driver cmos_platform_driver = {
1445         .remove         = cmos_platform_remove,
1446         .shutdown       = cmos_platform_shutdown,
1447         .driver = {
1448                 .name           = driver_name,
1449                 .pm             = &cmos_pm_ops,
1450                 .of_match_table = of_match_ptr(of_cmos_match),
1451         }
1452 };
1453
1454 #ifdef CONFIG_PNP
1455 static bool pnp_driver_registered;
1456 #endif
1457 static bool platform_driver_registered;
1458
1459 static int __init cmos_init(void)
1460 {
1461         int retval = 0;
1462
1463 #ifdef  CONFIG_PNP
1464         retval = pnp_register_driver(&cmos_pnp_driver);
1465         if (retval == 0)
1466                 pnp_driver_registered = true;
1467 #endif
1468
1469         if (!cmos_rtc.dev) {
1470                 retval = platform_driver_probe(&cmos_platform_driver,
1471                                                cmos_platform_probe);
1472                 if (retval == 0)
1473                         platform_driver_registered = true;
1474         }
1475
1476         if (retval == 0)
1477                 return 0;
1478
1479 #ifdef  CONFIG_PNP
1480         if (pnp_driver_registered)
1481                 pnp_unregister_driver(&cmos_pnp_driver);
1482 #endif
1483         return retval;
1484 }
1485 module_init(cmos_init);
1486
1487 static void __exit cmos_exit(void)
1488 {
1489 #ifdef  CONFIG_PNP
1490         if (pnp_driver_registered)
1491                 pnp_unregister_driver(&cmos_pnp_driver);
1492 #endif
1493         if (platform_driver_registered)
1494                 platform_driver_unregister(&cmos_platform_driver);
1495 }
1496 module_exit(cmos_exit);
1497
1498
1499 MODULE_AUTHOR("David Brownell");
1500 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1501 MODULE_LICENSE("GPL");