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 /*----------------------------------------------------------------*/
 578
 579 /*
 580  * All these chips have at least 64 bytes of address space, shared by
 581  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 582  * by boot firmware.  Modern chips have 128 or 256 bytes.
 583  */
 584
 585 #define NVRAM_OFFSET    (RTC_REG_D + 1)
 586
 587 static int cmos_nvram_read(void *priv, unsigned int off, void *val,
 588                            size_t count)
 589 {
 590         unsigned char *buf = val;
 591         int     retval;
 592
 593         off += NVRAM_OFFSET;
 594         spin_lock_irq(&rtc_lock);
 595         for (retval = 0; count; count--, off++, retval++) {
 596                 if (off < 128)
 597                         *buf++ = CMOS_READ(off);
 598                 else if (can_bank2)
 599                         *buf++ = cmos_read_bank2(off);
 600                 else
 601                         break;
 602         }
 603         spin_unlock_irq(&rtc_lock);
 604
 605         return retval;
 606 }
 607
 608 static int cmos_nvram_write(void *priv, unsigned int off, void *val,
 609                             size_t count)
 610 {
 611         struct cmos_rtc *cmos = priv;
 612         unsigned char   *buf = val;
 613         int             retval;
 614
 615         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 616          * checksum on part of the NVRAM data.  That's currently ignored
 617          * here.  If userspace is smart enough to know what fields of
 618          * NVRAM to update, updating checksums is also part of its job.
 619          */
 620         off += NVRAM_OFFSET;
 621         spin_lock_irq(&rtc_lock);
 622         for (retval = 0; count; count--, off++, retval++) {
 623                 /* don't trash RTC registers */
 624                 if (off == cmos->day_alrm
 625                                 || off == cmos->mon_alrm
 626                                 || off == cmos->century)
 627                         buf++;
 628                 else if (off < 128)
 629                         CMOS_WRITE(*buf++, off);
 630                 else if (can_bank2)
 631                         cmos_write_bank2(*buf++, off);
 632                 else
 633                         break;
 634         }
 635         spin_unlock_irq(&rtc_lock);
 636
 637         return retval;
 638 }
 639
 640 /*----------------------------------------------------------------*/
 641
 642 static struct cmos_rtc  cmos_rtc;
 643
 644 static irqreturn_t cmos_interrupt(int irq, void *p)
 645 {
 646         u8              irqstat;
 647         u8              rtc_control;
 648
 649         spin_lock(&rtc_lock);
 650
 651         /* When the HPET interrupt handler calls us, the interrupt
 652          * status is passed as arg1 instead of the irq number.  But
 653          * always clear irq status, even when HPET is in the way.
 654          *
 655          * Note that HPET and RTC are almost certainly out of phase,
 656          * giving different IRQ status ...
 657          */
 658         irqstat = CMOS_READ(RTC_INTR_FLAGS);
 659         rtc_control = CMOS_READ(RTC_CONTROL);
 660         if (use_hpet_alarm())
 661                 irqstat = (unsigned long)irq & 0xF0;
 662
 663         /* If we were suspended, RTC_CONTROL may not be accurate since the
 664          * bios may have cleared it.
 665          */
 666         if (!cmos_rtc.suspend_ctrl)
 667                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 668         else
 669                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 670
 671         /* All Linux RTC alarms should be treated as if they were oneshot.
 672          * Similar code may be needed in system wakeup paths, in case the
 673          * alarm woke the system.
 674          */
 675         if (irqstat & RTC_AIE) {
 676                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 677                 rtc_control &= ~RTC_AIE;
 678                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 679                 if (use_hpet_alarm())
 680                         hpet_mask_rtc_irq_bit(RTC_AIE);
 681                 CMOS_READ(RTC_INTR_FLAGS);
 682         }
 683         spin_unlock(&rtc_lock);
 684
 685         if (is_intr(irqstat)) {
 686                 rtc_update_irq(p, 1, irqstat);
 687                 return IRQ_HANDLED;
 688         } else
 689                 return IRQ_NONE;
 690 }
 691
 692 #ifdef  CONFIG_PNP
 693 #define INITSECTION
 694
 695 #else
 696 #define INITSECTION     __init
 697 #endif
 698
 699 static int INITSECTION
 700 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 701 {
 702         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
 703         int                             retval = 0;
 704         unsigned char                   rtc_control;
 705         unsigned                        address_space;
 706         u32                             flags = 0;
 707         struct nvmem_config nvmem_cfg = {
 708                 .name = "cmos_nvram",
 709                 .word_size = 1,
 710                 .stride = 1,
 711                 .reg_read = cmos_nvram_read,
 712                 .reg_write = cmos_nvram_write,
 713                 .priv = &cmos_rtc,
 714         };
 715
 716         /* there can be only one ... */
 717         if (cmos_rtc.dev)
 718                 return -EBUSY;
 719
 720         if (!ports)
 721                 return -ENODEV;
 722
 723         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 724          *
 725          * REVISIT non-x86 systems may instead use memory space resources
 726          * (needing ioremap etc), not i/o space resources like this ...
 727          */
 728         if (RTC_IOMAPPED)
 729                 ports = request_region(ports->start, resource_size(ports),
 730                                        driver_name);
 731         else
 732                 ports = request_mem_region(ports->start, resource_size(ports),
 733                                            driver_name);
 734         if (!ports) {
 735                 dev_dbg(dev, "i/o registers already in use\n");
 736                 return -EBUSY;
 737         }
 738
 739         cmos_rtc.irq = rtc_irq;
 740         cmos_rtc.iomem = ports;
 741
 742         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 743          * driver did, but don't reject unknown configs.   Old hardware
 744          * won't address 128 bytes.  Newer chips have multiple banks,
 745          * though they may not be listed in one I/O resource.
 746          */
 747 #if     defined(CONFIG_ATARI)
 748         address_space = 64;
 749 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 750                         || defined(__sparc__) || defined(__mips__) \
 751                         || defined(__powerpc__)
 752         address_space = 128;
 753 #else
 754 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 755         address_space = 128;
 756 #endif
 757         if (can_bank2 && ports->end > (ports->start + 1))
 758                 address_space = 256;
 759
 760         /* For ACPI systems extension info comes from the FADT.  On others,
 761          * board specific setup provides it as appropriate.  Systems where
 762          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 763          * some almost-clones) can provide hooks to make that behave.
 764          *
 765          * Note that ACPI doesn't preclude putting these registers into
 766          * "extended" areas of the chip, including some that we won't yet
 767          * expect CMOS_READ and friends to handle.
 768          */
 769         if (info) {
 770                 if (info->flags)
 771                         flags = info->flags;
 772                 if (info->address_space)
 773                         address_space = info->address_space;
 774
 775                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
 776                         cmos_rtc.day_alrm = info->rtc_day_alarm;
 777                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
 778                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
 779                 if (info->rtc_century && info->rtc_century < 128)
 780                         cmos_rtc.century = info->rtc_century;
 781
 782                 if (info->wake_on && info->wake_off) {
 783                         cmos_rtc.wake_on = info->wake_on;
 784                         cmos_rtc.wake_off = info->wake_off;
 785                 }
 786         }
 787
 788         cmos_rtc.dev = dev;
 789         dev_set_drvdata(dev, &cmos_rtc);
 790
 791         cmos_rtc.rtc = devm_rtc_allocate_device(dev);
 792         if (IS_ERR(cmos_rtc.rtc)) {
 793                 retval = PTR_ERR(cmos_rtc.rtc);
 794                 goto cleanup0;
 795         }
 796
 797         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 798
 799         spin_lock_irq(&rtc_lock);
 800
 801         /* Ensure that the RTC is accessible. Bit 6 must be 0! */
 802         if ((CMOS_READ(RTC_VALID) & 0x40) != 0) {
 803                 spin_unlock_irq(&rtc_lock);
 804                 dev_warn(dev, "not accessible\n");
 805                 retval = -ENXIO;
 806                 goto cleanup1;
 807         }
 808
 809         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
 810                 /* force periodic irq to CMOS reset default of 1024Hz;
 811                  *
 812                  * REVISIT it's been reported that at least one x86_64 ALI
 813                  * mobo doesn't use 32KHz here ... for portability we might
 814                  * need to do something about other clock frequencies.
 815                  */
 816                 cmos_rtc.rtc->irq_freq = 1024;
 817                 if (use_hpet_alarm())
 818                         hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
 819                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
 820         }
 821
 822         /* disable irqs */
 823         if (is_valid_irq(rtc_irq))
 824                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
 825
 826         rtc_control = CMOS_READ(RTC_CONTROL);
 827
 828         spin_unlock_irq(&rtc_lock);
 829
 830         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
 831                 dev_warn(dev, "only 24-hr supported\n");
 832                 retval = -ENXIO;
 833                 goto cleanup1;
 834         }
 835
 836         if (use_hpet_alarm())
 837                 hpet_rtc_timer_init();
 838
 839         if (is_valid_irq(rtc_irq)) {
 840                 irq_handler_t rtc_cmos_int_handler;
 841
 842                 if (use_hpet_alarm()) {
 843                         rtc_cmos_int_handler = hpet_rtc_interrupt;
 844                         retval = hpet_register_irq_handler(cmos_interrupt);
 845                         if (retval) {
 846                                 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
 847                                 dev_warn(dev, "hpet_register_irq_handler "
 848                                                 " failed in rtc_init().");
 849                                 goto cleanup1;
 850                         }
 851                 } else
 852                         rtc_cmos_int_handler = cmos_interrupt;
 853
 854                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
 855                                 0, dev_name(&cmos_rtc.rtc->dev),
 856                                 cmos_rtc.rtc);
 857                 if (retval < 0) {
 858                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
 859                         goto cleanup1;
 860                 }
 861         } else {
 862                 clear_bit(RTC_FEATURE_ALARM, cmos_rtc.rtc->features);
 863         }
 864
 865         cmos_rtc.rtc->ops = &cmos_rtc_ops;
 866
 867         retval = devm_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         devm_rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg);
 877
 878         dev_info(dev, "%s%s, %d bytes nvram%s\n",
 879                  !is_valid_irq(rtc_irq) ? "no alarms" :
 880                  cmos_rtc.mon_alrm ? "alarms up to one year" :
 881                  cmos_rtc.day_alrm ? "alarms up to one month" :
 882                  "alarms up to one day",
 883                  cmos_rtc.century ? ", y3k" : "",
 884                  nvmem_cfg.size,
 885                  use_hpet_alarm() ? ", hpet irqs" : "");
 886
 887         return 0;
 888
 889 cleanup2:
 890         if (is_valid_irq(rtc_irq))
 891                 free_irq(rtc_irq, cmos_rtc.rtc);
 892 cleanup1:
 893         cmos_rtc.dev = NULL;
 894 cleanup0:
 895         if (RTC_IOMAPPED)
 896                 release_region(ports->start, resource_size(ports));
 897         else
 898                 release_mem_region(ports->start, resource_size(ports));
 899         return retval;
 900 }
 901
 902 static void cmos_do_shutdown(int rtc_irq)
 903 {
 904         spin_lock_irq(&rtc_lock);
 905         if (is_valid_irq(rtc_irq))
 906                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
 907         spin_unlock_irq(&rtc_lock);
 908 }
 909
 910 static void cmos_do_remove(struct device *dev)
 911 {
 912         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 913         struct resource *ports;
 914
 915         cmos_do_shutdown(cmos->irq);
 916
 917         if (is_valid_irq(cmos->irq)) {
 918                 free_irq(cmos->irq, cmos->rtc);
 919                 if (use_hpet_alarm())
 920                         hpet_unregister_irq_handler(cmos_interrupt);
 921         }
 922
 923         cmos->rtc = NULL;
 924
 925         ports = cmos->iomem;
 926         if (RTC_IOMAPPED)
 927                 release_region(ports->start, resource_size(ports));
 928         else
 929                 release_mem_region(ports->start, resource_size(ports));
 930         cmos->iomem = NULL;
 931
 932         cmos->dev = NULL;
 933 }
 934
 935 static int cmos_aie_poweroff(struct device *dev)
 936 {
 937         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 938         struct rtc_time now;
 939         time64_t t_now;
 940         int retval = 0;
 941         unsigned char rtc_control;
 942
 943         if (!cmos->alarm_expires)
 944                 return -EINVAL;
 945
 946         spin_lock_irq(&rtc_lock);
 947         rtc_control = CMOS_READ(RTC_CONTROL);
 948         spin_unlock_irq(&rtc_lock);
 949
 950         /* We only care about the situation where AIE is disabled. */
 951         if (rtc_control & RTC_AIE)
 952                 return -EBUSY;
 953
 954         cmos_read_time(dev, &now);
 955         t_now = rtc_tm_to_time64(&now);
 956
 957         /*
 958          * When enabling "RTC wake-up" in BIOS setup, the machine reboots
 959          * automatically right after shutdown on some buggy boxes.
 960          * This automatic rebooting issue won't happen when the alarm
 961          * time is larger than now+1 seconds.
 962          *
 963          * If the alarm time is equal to now+1 seconds, the issue can be
 964          * prevented by cancelling the alarm.
 965          */
 966         if (cmos->alarm_expires == t_now + 1) {
 967                 struct rtc_wkalrm alarm;
 968
 969                 /* Cancel the AIE timer by configuring the past time. */
 970                 rtc_time64_to_tm(t_now - 1, &alarm.time);
 971                 alarm.enabled = 0;
 972                 retval = cmos_set_alarm(dev, &alarm);
 973         } else if (cmos->alarm_expires > t_now + 1) {
 974                 retval = -EBUSY;
 975         }
 976
 977         return retval;
 978 }
 979
 980 static int cmos_suspend(struct device *dev)
 981 {
 982         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 983         unsigned char   tmp;
 984
 985         /* only the alarm might be a wakeup event source */
 986         spin_lock_irq(&rtc_lock);
 987         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
 988         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 989                 unsigned char   mask;
 990
 991                 if (device_may_wakeup(dev))
 992                         mask = RTC_IRQMASK & ~RTC_AIE;
 993                 else
 994                         mask = RTC_IRQMASK;
 995                 tmp &= ~mask;
 996                 CMOS_WRITE(tmp, RTC_CONTROL);
 997                 if (use_hpet_alarm())
 998                         hpet_mask_rtc_irq_bit(mask);
 999                 cmos_checkintr(cmos, tmp);
1000         }
1001         spin_unlock_irq(&rtc_lock);
1002
1003         if ((tmp & RTC_AIE) && !cmos_use_acpi_alarm()) {
1004                 cmos->enabled_wake = 1;
1005                 if (cmos->wake_on)
1006                         cmos->wake_on(dev);
1007                 else
1008                         enable_irq_wake(cmos->irq);
1009         }
1010
1011         memset(&cmos->saved_wkalrm, 0, sizeof(struct rtc_wkalrm));
1012         cmos_read_alarm(dev, &cmos->saved_wkalrm);
1013
1014         dev_dbg(dev, "suspend%s, ctrl %02x\n",
1015                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
1016                         tmp);
1017
1018         return 0;
1019 }
1020
1021 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
1022  * after a detour through G3 "mechanical off", although the ACPI spec
1023  * says wakeup should only work from G1/S4 "hibernate".  To most users,
1024  * distinctions between S4 and S5 are pointless.  So when the hardware
1025  * allows, don't draw that distinction.
1026  */
1027 static inline int cmos_poweroff(struct device *dev)
1028 {
1029         if (!IS_ENABLED(CONFIG_PM))
1030                 return -ENOSYS;
1031
1032         return cmos_suspend(dev);
1033 }
1034
1035 static void cmos_check_wkalrm(struct device *dev)
1036 {
1037         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1038         struct rtc_wkalrm current_alarm;
1039         time64_t t_now;
1040         time64_t t_current_expires;
1041         time64_t t_saved_expires;
1042         struct rtc_time now;
1043
1044         /* Check if we have RTC Alarm armed */
1045         if (!(cmos->suspend_ctrl & RTC_AIE))
1046                 return;
1047
1048         cmos_read_time(dev, &now);
1049         t_now = rtc_tm_to_time64(&now);
1050
1051         /*
1052          * ACPI RTC wake event is cleared after resume from STR,
1053          * ACK the rtc irq here
1054          */
1055         if (t_now >= cmos->alarm_expires && cmos_use_acpi_alarm()) {
1056                 cmos_interrupt(0, (void *)cmos->rtc);
1057                 return;
1058         }
1059
1060         memset(&current_alarm, 0, sizeof(struct rtc_wkalrm));
1061         cmos_read_alarm(dev, &current_alarm);
1062         t_current_expires = rtc_tm_to_time64(&current_alarm.time);
1063         t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
1064         if (t_current_expires != t_saved_expires ||
1065             cmos->saved_wkalrm.enabled != current_alarm.enabled) {
1066                 cmos_set_alarm(dev, &cmos->saved_wkalrm);
1067         }
1068 }
1069
1070 static void cmos_check_acpi_rtc_status(struct device *dev,
1071                                        unsigned char *rtc_control);
1072
1073 static int __maybe_unused cmos_resume(struct device *dev)
1074 {
1075         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1076         unsigned char tmp;
1077
1078         if (cmos->enabled_wake && !cmos_use_acpi_alarm()) {
1079                 if (cmos->wake_off)
1080                         cmos->wake_off(dev);
1081                 else
1082                         disable_irq_wake(cmos->irq);
1083                 cmos->enabled_wake = 0;
1084         }
1085
1086         /* The BIOS might have changed the alarm, restore it */
1087         cmos_check_wkalrm(dev);
1088
1089         spin_lock_irq(&rtc_lock);
1090         tmp = cmos->suspend_ctrl;
1091         cmos->suspend_ctrl = 0;
1092         /* re-enable any irqs previously active */
1093         if (tmp & RTC_IRQMASK) {
1094                 unsigned char   mask;
1095
1096                 if (device_may_wakeup(dev) && use_hpet_alarm())
1097                         hpet_rtc_timer_init();
1098
1099                 do {
1100                         CMOS_WRITE(tmp, RTC_CONTROL);
1101                         if (use_hpet_alarm())
1102                                 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1103
1104                         mask = CMOS_READ(RTC_INTR_FLAGS);
1105                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1106                         if (!use_hpet_alarm() || !is_intr(mask))
1107                                 break;
1108
1109                         /* force one-shot behavior if HPET blocked
1110                          * the wake alarm's irq
1111                          */
1112                         rtc_update_irq(cmos->rtc, 1, mask);
1113                         tmp &= ~RTC_AIE;
1114                         hpet_mask_rtc_irq_bit(RTC_AIE);
1115                 } while (mask & RTC_AIE);
1116
1117                 if (tmp & RTC_AIE)
1118                         cmos_check_acpi_rtc_status(dev, &tmp);
1119         }
1120         spin_unlock_irq(&rtc_lock);
1121
1122         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1123
1124         return 0;
1125 }
1126
1127 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1128
1129 /*----------------------------------------------------------------*/
1130
1131 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1132  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1133  * probably list them in similar PNPBIOS tables; so PNP is more common.
1134  *
1135  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1136  * predate even PNPBIOS should set up platform_bus devices.
1137  */
1138
1139 #ifdef  CONFIG_ACPI
1140
1141 #include <linux/acpi.h>
1142
1143 static u32 rtc_handler(void *context)
1144 {
1145         struct device *dev = context;
1146         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1147         unsigned char rtc_control = 0;
1148         unsigned char rtc_intr;
1149         unsigned long flags;
1150
1151
1152         /*
1153          * Always update rtc irq when ACPI is used as RTC Alarm.
1154          * Or else, ACPI SCI is enabled during suspend/resume only,
1155          * update rtc irq in that case.
1156          */
1157         if (cmos_use_acpi_alarm())
1158                 cmos_interrupt(0, (void *)cmos->rtc);
1159         else {
1160                 /* Fix me: can we use cmos_interrupt() here as well? */
1161                 spin_lock_irqsave(&rtc_lock, flags);
1162                 if (cmos_rtc.suspend_ctrl)
1163                         rtc_control = CMOS_READ(RTC_CONTROL);
1164                 if (rtc_control & RTC_AIE) {
1165                         cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1166                         CMOS_WRITE(rtc_control, RTC_CONTROL);
1167                         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1168                         rtc_update_irq(cmos->rtc, 1, rtc_intr);
1169                 }
1170                 spin_unlock_irqrestore(&rtc_lock, flags);
1171         }
1172
1173         pm_wakeup_hard_event(dev);
1174         acpi_clear_event(ACPI_EVENT_RTC);
1175         acpi_disable_event(ACPI_EVENT_RTC, 0);
1176         return ACPI_INTERRUPT_HANDLED;
1177 }
1178
1179 static inline void rtc_wake_setup(struct device *dev)
1180 {
1181         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1182         /*
1183          * After the RTC handler is installed, the Fixed_RTC event should
1184          * be disabled. Only when the RTC alarm is set will it be enabled.
1185          */
1186         acpi_clear_event(ACPI_EVENT_RTC);
1187         acpi_disable_event(ACPI_EVENT_RTC, 0);
1188 }
1189
1190 static void rtc_wake_on(struct device *dev)
1191 {
1192         acpi_clear_event(ACPI_EVENT_RTC);
1193         acpi_enable_event(ACPI_EVENT_RTC, 0);
1194 }
1195
1196 static void rtc_wake_off(struct device *dev)
1197 {
1198         acpi_disable_event(ACPI_EVENT_RTC, 0);
1199 }
1200
1201 #ifdef CONFIG_X86
1202 /* Enable use_acpi_alarm mode for Intel platforms no earlier than 2015 */
1203 static void use_acpi_alarm_quirks(void)
1204 {
1205         if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
1206                 return;
1207
1208         if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
1209                 return;
1210
1211         if (!is_hpet_enabled())
1212                 return;
1213
1214         if (dmi_get_bios_year() < 2015)
1215                 return;
1216
1217         use_acpi_alarm = true;
1218 }
1219 #else
1220 static inline void use_acpi_alarm_quirks(void) { }
1221 #endif
1222
1223 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1224  * its device node and pass extra config data.  This helps its driver use
1225  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1226  * that this board's RTC is wakeup-capable (per ACPI spec).
1227  */
1228 static struct cmos_rtc_board_info acpi_rtc_info;
1229
1230 static void cmos_wake_setup(struct device *dev)
1231 {
1232         if (acpi_disabled)
1233                 return;
1234
1235         use_acpi_alarm_quirks();
1236
1237         rtc_wake_setup(dev);
1238         acpi_rtc_info.wake_on = rtc_wake_on;
1239         acpi_rtc_info.wake_off = rtc_wake_off;
1240
1241         /* workaround bug in some ACPI tables */
1242         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1243                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1244                         acpi_gbl_FADT.month_alarm);
1245                 acpi_gbl_FADT.month_alarm = 0;
1246         }
1247
1248         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1249         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1250         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1251
1252         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1253         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1254                 dev_info(dev, "RTC can wake from S4\n");
1255
1256         dev->platform_data = &acpi_rtc_info;
1257
1258         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1259         device_init_wakeup(dev, 1);
1260 }
1261
1262 static void cmos_check_acpi_rtc_status(struct device *dev,
1263                                        unsigned char *rtc_control)
1264 {
1265         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1266         acpi_event_status rtc_status;
1267         acpi_status status;
1268
1269         if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1270                 return;
1271
1272         status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1273         if (ACPI_FAILURE(status)) {
1274                 dev_err(dev, "Could not get RTC status\n");
1275         } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1276                 unsigned char mask;
1277                 *rtc_control &= ~RTC_AIE;
1278                 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1279                 mask = CMOS_READ(RTC_INTR_FLAGS);
1280                 rtc_update_irq(cmos->rtc, 1, mask);
1281         }
1282 }
1283
1284 #else
1285
1286 static void cmos_wake_setup(struct device *dev)
1287 {
1288 }
1289
1290 static void cmos_check_acpi_rtc_status(struct device *dev,
1291                                        unsigned char *rtc_control)
1292 {
1293 }
1294
1295 #endif
1296
1297 #ifdef  CONFIG_PNP
1298
1299 #include <linux/pnp.h>
1300
1301 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1302 {
1303         cmos_wake_setup(&pnp->dev);
1304
1305         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1306                 unsigned int irq = 0;
1307 #ifdef CONFIG_X86
1308                 /* Some machines contain a PNP entry for the RTC, but
1309                  * don't define the IRQ. It should always be safe to
1310                  * hardcode it on systems with a legacy PIC.
1311                  */
1312                 if (nr_legacy_irqs())
1313                         irq = RTC_IRQ;
1314 #endif
1315                 return cmos_do_probe(&pnp->dev,
1316                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1317         } else {
1318                 return cmos_do_probe(&pnp->dev,
1319                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1320                                 pnp_irq(pnp, 0));
1321         }
1322 }
1323
1324 static void cmos_pnp_remove(struct pnp_dev *pnp)
1325 {
1326         cmos_do_remove(&pnp->dev);
1327 }
1328
1329 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1330 {
1331         struct device *dev = &pnp->dev;
1332         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1333
1334         if (system_state == SYSTEM_POWER_OFF) {
1335                 int retval = cmos_poweroff(dev);
1336
1337                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1338                         return;
1339         }
1340
1341         cmos_do_shutdown(cmos->irq);
1342 }
1343
1344 static const struct pnp_device_id rtc_ids[] = {
1345         { .id = "PNP0b00", },
1346         { .id = "PNP0b01", },
1347         { .id = "PNP0b02", },
1348         { },
1349 };
1350 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1351
1352 static struct pnp_driver cmos_pnp_driver = {
1353         .name           = driver_name,
1354         .id_table       = rtc_ids,
1355         .probe          = cmos_pnp_probe,
1356         .remove         = cmos_pnp_remove,
1357         .shutdown       = cmos_pnp_shutdown,
1358
1359         /* flag ensures resume() gets called, and stops syslog spam */
1360         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1361         .driver         = {
1362                         .pm = &cmos_pm_ops,
1363         },
1364 };
1365
1366 #endif  /* CONFIG_PNP */
1367
1368 #ifdef CONFIG_OF
1369 static const struct of_device_id of_cmos_match[] = {
1370         {
1371                 .compatible = "motorola,mc146818",
1372         },
1373         { },
1374 };
1375 MODULE_DEVICE_TABLE(of, of_cmos_match);
1376
1377 static __init void cmos_of_init(struct platform_device *pdev)
1378 {
1379         struct device_node *node = pdev->dev.of_node;
1380         const __be32 *val;
1381
1382         if (!node)
1383                 return;
1384
1385         val = of_get_property(node, "ctrl-reg", NULL);
1386         if (val)
1387                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1388
1389         val = of_get_property(node, "freq-reg", NULL);
1390         if (val)
1391                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1392 }
1393 #else
1394 static inline void cmos_of_init(struct platform_device *pdev) {}
1395 #endif
1396 /*----------------------------------------------------------------*/
1397
1398 /* Platform setup should have set up an RTC device, when PNP is
1399  * unavailable ... this could happen even on (older) PCs.
1400  */
1401
1402 static int __init cmos_platform_probe(struct platform_device *pdev)
1403 {
1404         struct resource *resource;
1405         int irq;
1406
1407         cmos_of_init(pdev);
1408         cmos_wake_setup(&pdev->dev);
1409
1410         if (RTC_IOMAPPED)
1411                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1412         else
1413                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1414         irq = platform_get_irq(pdev, 0);
1415         if (irq < 0)
1416                 irq = -1;
1417
1418         return cmos_do_probe(&pdev->dev, resource, irq);
1419 }
1420
1421 static int cmos_platform_remove(struct platform_device *pdev)
1422 {
1423         cmos_do_remove(&pdev->dev);
1424         return 0;
1425 }
1426
1427 static void cmos_platform_shutdown(struct platform_device *pdev)
1428 {
1429         struct device *dev = &pdev->dev;
1430         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1431
1432         if (system_state == SYSTEM_POWER_OFF) {
1433                 int retval = cmos_poweroff(dev);
1434
1435                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1436                         return;
1437         }
1438
1439         cmos_do_shutdown(cmos->irq);
1440 }
1441
1442 /* work with hotplug and coldplug */
1443 MODULE_ALIAS("platform:rtc_cmos");
1444
1445 static struct platform_driver cmos_platform_driver = {
1446         .remove         = cmos_platform_remove,
1447         .shutdown       = cmos_platform_shutdown,
1448         .driver = {
1449                 .name           = driver_name,
1450                 .pm             = &cmos_pm_ops,
1451                 .of_match_table = of_match_ptr(of_cmos_match),
1452         }
1453 };
1454
1455 #ifdef CONFIG_PNP
1456 static bool pnp_driver_registered;
1457 #endif
1458 static bool platform_driver_registered;
1459
1460 static int __init cmos_init(void)
1461 {
1462         int retval = 0;
1463
1464 #ifdef  CONFIG_PNP
1465         retval = pnp_register_driver(&cmos_pnp_driver);
1466         if (retval == 0)
1467                 pnp_driver_registered = true;
1468 #endif
1469
1470         if (!cmos_rtc.dev) {
1471                 retval = platform_driver_probe(&cmos_platform_driver,
1472                                                cmos_platform_probe);
1473                 if (retval == 0)
1474                         platform_driver_registered = true;
1475         }
1476
1477         if (retval == 0)
1478                 return 0;
1479
1480 #ifdef  CONFIG_PNP
1481         if (pnp_driver_registered)
1482                 pnp_unregister_driver(&cmos_pnp_driver);
1483 #endif
1484         return retval;
1485 }
1486 module_init(cmos_init);
1487
1488 static void __exit cmos_exit(void)
1489 {
1490 #ifdef  CONFIG_PNP
1491         if (pnp_driver_registered)
1492                 pnp_unregister_driver(&cmos_pnp_driver);
1493 #endif
1494         if (platform_driver_registered)
1495                 platform_driver_unregister(&cmos_platform_driver);
1496 }
1497 module_exit(cmos_exit);
1498
1499
1500 MODULE_AUTHOR("David Brownell");
1501 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1502 MODULE_LICENSE("GPL");