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         mc146818_get_time(t);
 233         return 0;
 234 }
 235
 236 static int cmos_set_time(struct device *dev, struct rtc_time *t)
 237 {
 238         /* NOTE: this ignores the issue whereby updating the seconds
 239          * takes effect exactly 500ms after we write the register.
 240          * (Also queueing and other delays before we get this far.)
 241          */
 242         return mc146818_set_time(t);
 243 }
 244
 245 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 246 {
 247         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 248         unsigned char   rtc_control;
 249
 250         /* This not only a rtc_op, but also called directly */
 251         if (!is_valid_irq(cmos->irq))
 252                 return -EIO;
 253
 254         /* Basic alarms only support hour, minute, and seconds fields.
 255          * Some also support day and month, for alarms up to a year in
 256          * the future.
 257          */
 258
 259         spin_lock_irq(&rtc_lock);
 260         t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
 261         t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
 262         t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 263
 264         if (cmos->day_alrm) {
 265                 /* ignore upper bits on readback per ACPI spec */
 266                 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
 267                 if (!t->time.tm_mday)
 268                         t->time.tm_mday = -1;
 269
 270                 if (cmos->mon_alrm) {
 271                         t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
 272                         if (!t->time.tm_mon)
 273                                 t->time.tm_mon = -1;
 274                 }
 275         }
 276
 277         rtc_control = CMOS_READ(RTC_CONTROL);
 278         spin_unlock_irq(&rtc_lock);
 279
 280         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 281                 if (((unsigned)t->time.tm_sec) < 0x60)
 282                         t->time.tm_sec = bcd2bin(t->time.tm_sec);
 283                 else
 284                         t->time.tm_sec = -1;
 285                 if (((unsigned)t->time.tm_min) < 0x60)
 286                         t->time.tm_min = bcd2bin(t->time.tm_min);
 287                 else
 288                         t->time.tm_min = -1;
 289                 if (((unsigned)t->time.tm_hour) < 0x24)
 290                         t->time.tm_hour = bcd2bin(t->time.tm_hour);
 291                 else
 292                         t->time.tm_hour = -1;
 293
 294                 if (cmos->day_alrm) {
 295                         if (((unsigned)t->time.tm_mday) <= 0x31)
 296                                 t->time.tm_mday = bcd2bin(t->time.tm_mday);
 297                         else
 298                                 t->time.tm_mday = -1;
 299
 300                         if (cmos->mon_alrm) {
 301                                 if (((unsigned)t->time.tm_mon) <= 0x12)
 302                                         t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
 303                                 else
 304                                         t->time.tm_mon = -1;
 305                         }
 306                 }
 307         }
 308
 309         t->enabled = !!(rtc_control & RTC_AIE);
 310         t->pending = 0;
 311
 312         return 0;
 313 }
 314
 315 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
 316 {
 317         unsigned char   rtc_intr;
 318
 319         /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
 320          * allegedly some older rtcs need that to handle irqs properly
 321          */
 322         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 323
 324         if (use_hpet_alarm())
 325                 return;
 326
 327         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 328         if (is_intr(rtc_intr))
 329                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
 330 }
 331
 332 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
 333 {
 334         unsigned char   rtc_control;
 335
 336         /* flush any pending IRQ status, notably for update irqs,
 337          * before we enable new IRQs
 338          */
 339         rtc_control = CMOS_READ(RTC_CONTROL);
 340         cmos_checkintr(cmos, rtc_control);
 341
 342         rtc_control |= mask;
 343         CMOS_WRITE(rtc_control, RTC_CONTROL);
 344         if (use_hpet_alarm())
 345                 hpet_set_rtc_irq_bit(mask);
 346
 347         if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
 348                 if (cmos->wake_on)
 349                         cmos->wake_on(cmos->dev);
 350         }
 351
 352         cmos_checkintr(cmos, rtc_control);
 353 }
 354
 355 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
 356 {
 357         unsigned char   rtc_control;
 358
 359         rtc_control = CMOS_READ(RTC_CONTROL);
 360         rtc_control &= ~mask;
 361         CMOS_WRITE(rtc_control, RTC_CONTROL);
 362         if (use_hpet_alarm())
 363                 hpet_mask_rtc_irq_bit(mask);
 364
 365         if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
 366                 if (cmos->wake_off)
 367                         cmos->wake_off(cmos->dev);
 368         }
 369
 370         cmos_checkintr(cmos, rtc_control);
 371 }
 372
 373 static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t)
 374 {
 375         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 376         struct rtc_time now;
 377
 378         cmos_read_time(dev, &now);
 379
 380         if (!cmos->day_alrm) {
 381                 time64_t t_max_date;
 382                 time64_t t_alrm;
 383
 384                 t_max_date = rtc_tm_to_time64(&now);
 385                 t_max_date += 24 * 60 * 60 - 1;
 386                 t_alrm = rtc_tm_to_time64(&t->time);
 387                 if (t_alrm > t_max_date) {
 388                         dev_err(dev,
 389                                 "Alarms can be up to one day in the future\n");
 390                         return -EINVAL;
 391                 }
 392         } else if (!cmos->mon_alrm) {
 393                 struct rtc_time max_date = now;
 394                 time64_t t_max_date;
 395                 time64_t t_alrm;
 396                 int max_mday;
 397
 398                 if (max_date.tm_mon == 11) {
 399                         max_date.tm_mon = 0;
 400                         max_date.tm_year += 1;
 401                 } else {
 402                         max_date.tm_mon += 1;
 403                 }
 404                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 405                 if (max_date.tm_mday > max_mday)
 406                         max_date.tm_mday = max_mday;
 407
 408                 t_max_date = rtc_tm_to_time64(&max_date);
 409                 t_max_date -= 1;
 410                 t_alrm = rtc_tm_to_time64(&t->time);
 411                 if (t_alrm > t_max_date) {
 412                         dev_err(dev,
 413                                 "Alarms can be up to one month in the future\n");
 414                         return -EINVAL;
 415                 }
 416         } else {
 417                 struct rtc_time max_date = now;
 418                 time64_t t_max_date;
 419                 time64_t t_alrm;
 420                 int max_mday;
 421
 422                 max_date.tm_year += 1;
 423                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 424                 if (max_date.tm_mday > max_mday)
 425                         max_date.tm_mday = max_mday;
 426
 427                 t_max_date = rtc_tm_to_time64(&max_date);
 428                 t_max_date -= 1;
 429                 t_alrm = rtc_tm_to_time64(&t->time);
 430                 if (t_alrm > t_max_date) {
 431                         dev_err(dev,
 432                                 "Alarms can be up to one year in the future\n");
 433                         return -EINVAL;
 434                 }
 435         }
 436
 437         return 0;
 438 }
 439
 440 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 441 {
 442         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 443         unsigned char mon, mday, hrs, min, sec, rtc_control;
 444         int ret;
 445
 446         /* This not only a rtc_op, but also called directly */
 447         if (!is_valid_irq(cmos->irq))
 448                 return -EIO;
 449
 450         ret = cmos_validate_alarm(dev, t);
 451         if (ret < 0)
 452                 return ret;
 453
 454         mon = t->time.tm_mon + 1;
 455         mday = t->time.tm_mday;
 456         hrs = t->time.tm_hour;
 457         min = t->time.tm_min;
 458         sec = t->time.tm_sec;
 459
 460         spin_lock_irq(&rtc_lock);
 461         rtc_control = CMOS_READ(RTC_CONTROL);
 462         spin_unlock_irq(&rtc_lock);
 463
 464         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 465                 /* Writing 0xff means "don't care" or "match all".  */
 466                 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
 467                 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 468                 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
 469                 min = (min < 60) ? bin2bcd(min) : 0xff;
 470                 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
 471         }
 472
 473         spin_lock_irq(&rtc_lock);
 474
 475         /* next rtc irq must not be from previous alarm setting */
 476         cmos_irq_disable(cmos, RTC_AIE);
 477
 478         /* update alarm */
 479         CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 480         CMOS_WRITE(min, RTC_MINUTES_ALARM);
 481         CMOS_WRITE(sec, RTC_SECONDS_ALARM);
 482
 483         /* the system may support an "enhanced" alarm */
 484         if (cmos->day_alrm) {
 485                 CMOS_WRITE(mday, cmos->day_alrm);
 486                 if (cmos->mon_alrm)
 487                         CMOS_WRITE(mon, cmos->mon_alrm);
 488         }
 489
 490         if (use_hpet_alarm()) {
 491                 /*
 492                  * FIXME the HPET alarm glue currently ignores day_alrm
 493                  * and mon_alrm ...
 494                  */
 495                 hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min,
 496                                     t->time.tm_sec);
 497         }
 498
 499         if (t->enabled)
 500                 cmos_irq_enable(cmos, RTC_AIE);
 501
 502         spin_unlock_irq(&rtc_lock);
 503
 504         cmos->alarm_expires = rtc_tm_to_time64(&t->time);
 505
 506         return 0;
 507 }
 508
 509 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 510 {
 511         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 512         unsigned long   flags;
 513
 514         spin_lock_irqsave(&rtc_lock, flags);
 515
 516         if (enabled)
 517                 cmos_irq_enable(cmos, RTC_AIE);
 518         else
 519                 cmos_irq_disable(cmos, RTC_AIE);
 520
 521         spin_unlock_irqrestore(&rtc_lock, flags);
 522         return 0;
 523 }
 524
 525 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 526
 527 static int cmos_procfs(struct device *dev, struct seq_file *seq)
 528 {
 529         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 530         unsigned char   rtc_control, valid;
 531
 532         spin_lock_irq(&rtc_lock);
 533         rtc_control = CMOS_READ(RTC_CONTROL);
 534         valid = CMOS_READ(RTC_VALID);
 535         spin_unlock_irq(&rtc_lock);
 536
 537         /* NOTE:  at least ICH6 reports battery status using a different
 538          * (non-RTC) bit; and SQWE is ignored on many current systems.
 539          */
 540         seq_printf(seq,
 541                    "periodic_IRQ\t: %s\n"
 542                    "update_IRQ\t: %s\n"
 543                    "HPET_emulated\t: %s\n"
 544                    // "square_wave\t: %s\n"
 545                    "BCD\t\t: %s\n"
 546                    "DST_enable\t: %s\n"
 547                    "periodic_freq\t: %d\n"
 548                    "batt_status\t: %s\n",
 549                    (rtc_control & RTC_PIE) ? "yes" : "no",
 550                    (rtc_control & RTC_UIE) ? "yes" : "no",
 551                    use_hpet_alarm() ? "yes" : "no",
 552                    // (rtc_control & RTC_SQWE) ? "yes" : "no",
 553                    (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 554                    (rtc_control & RTC_DST_EN) ? "yes" : "no",
 555                    cmos->rtc->irq_freq,
 556                    (valid & RTC_VRT) ? "okay" : "dead");
 557
 558         return 0;
 559 }
 560
 561 #else
 562 #define cmos_procfs     NULL
 563 #endif
 564
 565 static const struct rtc_class_ops cmos_rtc_ops = {
 566         .read_time              = cmos_read_time,
 567         .set_time               = cmos_set_time,
 568         .read_alarm             = cmos_read_alarm,
 569         .set_alarm              = cmos_set_alarm,
 570         .proc                   = cmos_procfs,
 571         .alarm_irq_enable       = cmos_alarm_irq_enable,
 572 };
 573
 574 /*----------------------------------------------------------------*/
 575
 576 /*
 577  * All these chips have at least 64 bytes of address space, shared by
 578  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 579  * by boot firmware.  Modern chips have 128 or 256 bytes.
 580  */
 581
 582 #define NVRAM_OFFSET    (RTC_REG_D + 1)
 583
 584 static int cmos_nvram_read(void *priv, unsigned int off, void *val,
 585                            size_t count)
 586 {
 587         unsigned char *buf = val;
 588         int     retval;
 589
 590         off += NVRAM_OFFSET;
 591         spin_lock_irq(&rtc_lock);
 592         for (retval = 0; count; count--, off++, retval++) {
 593                 if (off < 128)
 594                         *buf++ = CMOS_READ(off);
 595                 else if (can_bank2)
 596                         *buf++ = cmos_read_bank2(off);
 597                 else
 598                         break;
 599         }
 600         spin_unlock_irq(&rtc_lock);
 601
 602         return retval;
 603 }
 604
 605 static int cmos_nvram_write(void *priv, unsigned int off, void *val,
 606                             size_t count)
 607 {
 608         struct cmos_rtc *cmos = priv;
 609         unsigned char   *buf = val;
 610         int             retval;
 611
 612         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 613          * checksum on part of the NVRAM data.  That's currently ignored
 614          * here.  If userspace is smart enough to know what fields of
 615          * NVRAM to update, updating checksums is also part of its job.
 616          */
 617         off += NVRAM_OFFSET;
 618         spin_lock_irq(&rtc_lock);
 619         for (retval = 0; count; count--, off++, retval++) {
 620                 /* don't trash RTC registers */
 621                 if (off == cmos->day_alrm
 622                                 || off == cmos->mon_alrm
 623                                 || off == cmos->century)
 624                         buf++;
 625                 else if (off < 128)
 626                         CMOS_WRITE(*buf++, off);
 627                 else if (can_bank2)
 628                         cmos_write_bank2(*buf++, off);
 629                 else
 630                         break;
 631         }
 632         spin_unlock_irq(&rtc_lock);
 633
 634         return retval;
 635 }
 636
 637 /*----------------------------------------------------------------*/
 638
 639 static struct cmos_rtc  cmos_rtc;
 640
 641 static irqreturn_t cmos_interrupt(int irq, void *p)
 642 {
 643         u8              irqstat;
 644         u8              rtc_control;
 645
 646         spin_lock(&rtc_lock);
 647
 648         /* When the HPET interrupt handler calls us, the interrupt
 649          * status is passed as arg1 instead of the irq number.  But
 650          * always clear irq status, even when HPET is in the way.
 651          *
 652          * Note that HPET and RTC are almost certainly out of phase,
 653          * giving different IRQ status ...
 654          */
 655         irqstat = CMOS_READ(RTC_INTR_FLAGS);
 656         rtc_control = CMOS_READ(RTC_CONTROL);
 657         if (use_hpet_alarm())
 658                 irqstat = (unsigned long)irq & 0xF0;
 659
 660         /* If we were suspended, RTC_CONTROL may not be accurate since the
 661          * bios may have cleared it.
 662          */
 663         if (!cmos_rtc.suspend_ctrl)
 664                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 665         else
 666                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 667
 668         /* All Linux RTC alarms should be treated as if they were oneshot.
 669          * Similar code may be needed in system wakeup paths, in case the
 670          * alarm woke the system.
 671          */
 672         if (irqstat & RTC_AIE) {
 673                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 674                 rtc_control &= ~RTC_AIE;
 675                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 676                 if (use_hpet_alarm())
 677                         hpet_mask_rtc_irq_bit(RTC_AIE);
 678                 CMOS_READ(RTC_INTR_FLAGS);
 679         }
 680         spin_unlock(&rtc_lock);
 681
 682         if (is_intr(irqstat)) {
 683                 rtc_update_irq(p, 1, irqstat);
 684                 return IRQ_HANDLED;
 685         } else
 686                 return IRQ_NONE;
 687 }
 688
 689 #ifdef  CONFIG_PNP
 690 #define INITSECTION
 691
 692 #else
 693 #define INITSECTION     __init
 694 #endif
 695
 696 static int INITSECTION
 697 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 698 {
 699         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
 700         int                             retval = 0;
 701         unsigned char                   rtc_control;
 702         unsigned                        address_space;
 703         u32                             flags = 0;
 704         struct nvmem_config nvmem_cfg = {
 705                 .name = "cmos_nvram",
 706                 .word_size = 1,
 707                 .stride = 1,
 708                 .reg_read = cmos_nvram_read,
 709                 .reg_write = cmos_nvram_write,
 710                 .priv = &cmos_rtc,
 711         };
 712
 713         /* there can be only one ... */
 714         if (cmos_rtc.dev)
 715                 return -EBUSY;
 716
 717         if (!ports)
 718                 return -ENODEV;
 719
 720         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 721          *
 722          * REVISIT non-x86 systems may instead use memory space resources
 723          * (needing ioremap etc), not i/o space resources like this ...
 724          */
 725         if (RTC_IOMAPPED)
 726                 ports = request_region(ports->start, resource_size(ports),
 727                                        driver_name);
 728         else
 729                 ports = request_mem_region(ports->start, resource_size(ports),
 730                                            driver_name);
 731         if (!ports) {
 732                 dev_dbg(dev, "i/o registers already in use\n");
 733                 return -EBUSY;
 734         }
 735
 736         cmos_rtc.irq = rtc_irq;
 737         cmos_rtc.iomem = ports;
 738
 739         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 740          * driver did, but don't reject unknown configs.   Old hardware
 741          * won't address 128 bytes.  Newer chips have multiple banks,
 742          * though they may not be listed in one I/O resource.
 743          */
 744 #if     defined(CONFIG_ATARI)
 745         address_space = 64;
 746 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 747                         || defined(__sparc__) || defined(__mips__) \
 748                         || defined(__powerpc__)
 749         address_space = 128;
 750 #else
 751 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 752         address_space = 128;
 753 #endif
 754         if (can_bank2 && ports->end > (ports->start + 1))
 755                 address_space = 256;
 756
 757         /* For ACPI systems extension info comes from the FADT.  On others,
 758          * board specific setup provides it as appropriate.  Systems where
 759          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 760          * some almost-clones) can provide hooks to make that behave.
 761          *
 762          * Note that ACPI doesn't preclude putting these registers into
 763          * "extended" areas of the chip, including some that we won't yet
 764          * expect CMOS_READ and friends to handle.
 765          */
 766         if (info) {
 767                 if (info->flags)
 768                         flags = info->flags;
 769                 if (info->address_space)
 770                         address_space = info->address_space;
 771
 772                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
 773                         cmos_rtc.day_alrm = info->rtc_day_alarm;
 774                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
 775                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
 776                 if (info->rtc_century && info->rtc_century < 128)
 777                         cmos_rtc.century = info->rtc_century;
 778
 779                 if (info->wake_on && info->wake_off) {
 780                         cmos_rtc.wake_on = info->wake_on;
 781                         cmos_rtc.wake_off = info->wake_off;
 782                 }
 783         }
 784
 785         cmos_rtc.dev = dev;
 786         dev_set_drvdata(dev, &cmos_rtc);
 787
 788         cmos_rtc.rtc = devm_rtc_allocate_device(dev);
 789         if (IS_ERR(cmos_rtc.rtc)) {
 790                 retval = PTR_ERR(cmos_rtc.rtc);
 791                 goto cleanup0;
 792         }
 793
 794         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 795
 796         spin_lock_irq(&rtc_lock);
 797
 798         /* Ensure that the RTC is accessible. Bit 6 must be 0! */
 799         if ((CMOS_READ(RTC_VALID) & 0x40) != 0) {
 800                 spin_unlock_irq(&rtc_lock);
 801                 dev_warn(dev, "not accessible\n");
 802                 retval = -ENXIO;
 803                 goto cleanup1;
 804         }
 805
 806         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
 807                 /* force periodic irq to CMOS reset default of 1024Hz;
 808                  *
 809                  * REVISIT it's been reported that at least one x86_64 ALI
 810                  * mobo doesn't use 32KHz here ... for portability we might
 811                  * need to do something about other clock frequencies.
 812                  */
 813                 cmos_rtc.rtc->irq_freq = 1024;
 814                 if (use_hpet_alarm())
 815                         hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
 816                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
 817         }
 818
 819         /* disable irqs */
 820         if (is_valid_irq(rtc_irq))
 821                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
 822
 823         rtc_control = CMOS_READ(RTC_CONTROL);
 824
 825         spin_unlock_irq(&rtc_lock);
 826
 827         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
 828                 dev_warn(dev, "only 24-hr supported\n");
 829                 retval = -ENXIO;
 830                 goto cleanup1;
 831         }
 832
 833         if (use_hpet_alarm())
 834                 hpet_rtc_timer_init();
 835
 836         if (is_valid_irq(rtc_irq)) {
 837                 irq_handler_t rtc_cmos_int_handler;
 838
 839                 if (use_hpet_alarm()) {
 840                         rtc_cmos_int_handler = hpet_rtc_interrupt;
 841                         retval = hpet_register_irq_handler(cmos_interrupt);
 842                         if (retval) {
 843                                 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
 844                                 dev_warn(dev, "hpet_register_irq_handler "
 845                                                 " failed in rtc_init().");
 846                                 goto cleanup1;
 847                         }
 848                 } else
 849                         rtc_cmos_int_handler = cmos_interrupt;
 850
 851                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
 852                                 0, dev_name(&cmos_rtc.rtc->dev),
 853                                 cmos_rtc.rtc);
 854                 if (retval < 0) {
 855                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
 856                         goto cleanup1;
 857                 }
 858         } else {
 859                 clear_bit(RTC_FEATURE_ALARM, cmos_rtc.rtc->features);
 860         }
 861
 862         cmos_rtc.rtc->ops = &cmos_rtc_ops;
 863
 864         retval = devm_rtc_register_device(cmos_rtc.rtc);
 865         if (retval)
 866                 goto cleanup2;
 867
 868         /* Set the sync offset for the periodic 11min update correct */
 869         cmos_rtc.rtc->set_offset_nsec = NSEC_PER_SEC / 2;
 870
 871         /* export at least the first block of NVRAM */
 872         nvmem_cfg.size = address_space - NVRAM_OFFSET;
 873         devm_rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg);
 874
 875         dev_info(dev, "%s%s, %d bytes nvram%s\n",
 876                  !is_valid_irq(rtc_irq) ? "no alarms" :
 877                  cmos_rtc.mon_alrm ? "alarms up to one year" :
 878                  cmos_rtc.day_alrm ? "alarms up to one month" :
 879                  "alarms up to one day",
 880                  cmos_rtc.century ? ", y3k" : "",
 881                  nvmem_cfg.size,
 882                  use_hpet_alarm() ? ", hpet irqs" : "");
 883
 884         return 0;
 885
 886 cleanup2:
 887         if (is_valid_irq(rtc_irq))
 888                 free_irq(rtc_irq, cmos_rtc.rtc);
 889 cleanup1:
 890         cmos_rtc.dev = NULL;
 891 cleanup0:
 892         if (RTC_IOMAPPED)
 893                 release_region(ports->start, resource_size(ports));
 894         else
 895                 release_mem_region(ports->start, resource_size(ports));
 896         return retval;
 897 }
 898
 899 static void cmos_do_shutdown(int rtc_irq)
 900 {
 901         spin_lock_irq(&rtc_lock);
 902         if (is_valid_irq(rtc_irq))
 903                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
 904         spin_unlock_irq(&rtc_lock);
 905 }
 906
 907 static void cmos_do_remove(struct device *dev)
 908 {
 909         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 910         struct resource *ports;
 911
 912         cmos_do_shutdown(cmos->irq);
 913
 914         if (is_valid_irq(cmos->irq)) {
 915                 free_irq(cmos->irq, cmos->rtc);
 916                 if (use_hpet_alarm())
 917                         hpet_unregister_irq_handler(cmos_interrupt);
 918         }
 919
 920         cmos->rtc = NULL;
 921
 922         ports = cmos->iomem;
 923         if (RTC_IOMAPPED)
 924                 release_region(ports->start, resource_size(ports));
 925         else
 926                 release_mem_region(ports->start, resource_size(ports));
 927         cmos->iomem = NULL;
 928
 929         cmos->dev = NULL;
 930 }
 931
 932 static int cmos_aie_poweroff(struct device *dev)
 933 {
 934         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 935         struct rtc_time now;
 936         time64_t t_now;
 937         int retval = 0;
 938         unsigned char rtc_control;
 939
 940         if (!cmos->alarm_expires)
 941                 return -EINVAL;
 942
 943         spin_lock_irq(&rtc_lock);
 944         rtc_control = CMOS_READ(RTC_CONTROL);
 945         spin_unlock_irq(&rtc_lock);
 946
 947         /* We only care about the situation where AIE is disabled. */
 948         if (rtc_control & RTC_AIE)
 949                 return -EBUSY;
 950
 951         cmos_read_time(dev, &now);
 952         t_now = rtc_tm_to_time64(&now);
 953
 954         /*
 955          * When enabling "RTC wake-up" in BIOS setup, the machine reboots
 956          * automatically right after shutdown on some buggy boxes.
 957          * This automatic rebooting issue won't happen when the alarm
 958          * time is larger than now+1 seconds.
 959          *
 960          * If the alarm time is equal to now+1 seconds, the issue can be
 961          * prevented by cancelling the alarm.
 962          */
 963         if (cmos->alarm_expires == t_now + 1) {
 964                 struct rtc_wkalrm alarm;
 965
 966                 /* Cancel the AIE timer by configuring the past time. */
 967                 rtc_time64_to_tm(t_now - 1, &alarm.time);
 968                 alarm.enabled = 0;
 969                 retval = cmos_set_alarm(dev, &alarm);
 970         } else if (cmos->alarm_expires > t_now + 1) {
 971                 retval = -EBUSY;
 972         }
 973
 974         return retval;
 975 }
 976
 977 static int cmos_suspend(struct device *dev)
 978 {
 979         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 980         unsigned char   tmp;
 981
 982         /* only the alarm might be a wakeup event source */
 983         spin_lock_irq(&rtc_lock);
 984         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
 985         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 986                 unsigned char   mask;
 987
 988                 if (device_may_wakeup(dev))
 989                         mask = RTC_IRQMASK & ~RTC_AIE;
 990                 else
 991                         mask = RTC_IRQMASK;
 992                 tmp &= ~mask;
 993                 CMOS_WRITE(tmp, RTC_CONTROL);
 994                 if (use_hpet_alarm())
 995                         hpet_mask_rtc_irq_bit(mask);
 996                 cmos_checkintr(cmos, tmp);
 997         }
 998         spin_unlock_irq(&rtc_lock);
 999
1000         if ((tmp & RTC_AIE) && !cmos_use_acpi_alarm()) {
1001                 cmos->enabled_wake = 1;
1002                 if (cmos->wake_on)
1003                         cmos->wake_on(dev);
1004                 else
1005                         enable_irq_wake(cmos->irq);
1006         }
1007
1008         memset(&cmos->saved_wkalrm, 0, sizeof(struct rtc_wkalrm));
1009         cmos_read_alarm(dev, &cmos->saved_wkalrm);
1010
1011         dev_dbg(dev, "suspend%s, ctrl %02x\n",
1012                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
1013                         tmp);
1014
1015         return 0;
1016 }
1017
1018 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
1019  * after a detour through G3 "mechanical off", although the ACPI spec
1020  * says wakeup should only work from G1/S4 "hibernate".  To most users,
1021  * distinctions between S4 and S5 are pointless.  So when the hardware
1022  * allows, don't draw that distinction.
1023  */
1024 static inline int cmos_poweroff(struct device *dev)
1025 {
1026         if (!IS_ENABLED(CONFIG_PM))
1027                 return -ENOSYS;
1028
1029         return cmos_suspend(dev);
1030 }
1031
1032 static void cmos_check_wkalrm(struct device *dev)
1033 {
1034         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1035         struct rtc_wkalrm current_alarm;
1036         time64_t t_now;
1037         time64_t t_current_expires;
1038         time64_t t_saved_expires;
1039         struct rtc_time now;
1040
1041         /* Check if we have RTC Alarm armed */
1042         if (!(cmos->suspend_ctrl & RTC_AIE))
1043                 return;
1044
1045         cmos_read_time(dev, &now);
1046         t_now = rtc_tm_to_time64(&now);
1047
1048         /*
1049          * ACPI RTC wake event is cleared after resume from STR,
1050          * ACK the rtc irq here
1051          */
1052         if (t_now >= cmos->alarm_expires && cmos_use_acpi_alarm()) {
1053                 local_irq_disable();
1054                 cmos_interrupt(0, (void *)cmos->rtc);
1055                 local_irq_enable();
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");