drivers/rtc/rtc-cmos.c

   1 /*
   2  * RTC class driver for "CMOS RTC":  PCs, ACPI, etc
   3  *
   4  * Copyright (C) 1996 Paul Gortmaker (drivers/char/rtc.c)
   5  * Copyright (C) 2006 David Brownell (convert to new framework)
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the License, or (at your option) any later version.
  11  */
  12
  13 /*
  14  * The original "cmos clock" chip was an MC146818 chip, now obsolete.
  15  * That defined the register interface now provided by all PCs, some
  16  * non-PC systems, and incorporated into ACPI.  Modern PC chipsets
  17  * integrate an MC146818 clone in their southbridge, and boards use
  18  * that instead of discrete clones like the DS12887 or M48T86.  There
  19  * are also clones that connect using the LPC bus.
  20  *
  21  * That register API is also used directly by various other drivers
  22  * (notably for integrated NVRAM), infrastructure (x86 has code to
  23  * bypass the RTC framework, directly reading the RTC during boot
  24  * and updating minutes/seconds for systems using NTP synch) and
  25  * utilities (like userspace 'hwclock', if no /dev node exists).
  26  *
  27  * So **ALL** calls to CMOS_READ and CMOS_WRITE must be done with
  28  * interrupts disabled, holding the global rtc_lock, to exclude those
  29  * other drivers and utilities on correctly configured systems.
  30  */
  31
  32 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  33
  34 #include <linux/kernel.h>
  35 #include <linux/module.h>
  36 #include <linux/init.h>
  37 #include <linux/interrupt.h>
  38 #include <linux/spinlock.h>
  39 #include <linux/platform_device.h>
  40 #include <linux/log2.h>
  41 #include <linux/pm.h>
  42 #include <linux/of.h>
  43 #include <linux/of_platform.h>
  44 #ifdef CONFIG_X86
  45 #include <asm/i8259.h>
  46 #include <asm/processor.h>
  47 #include <linux/dmi.h>
  48 #endif
  49
  50 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
  51 #include <linux/mc146818rtc.h>
  52
  53 #ifdef CONFIG_ACPI
  54 /*
  55  * Use ACPI SCI to replace HPET interrupt for RTC Alarm event
  56  *
  57  * If cleared, ACPI SCI is only used to wake up the system from suspend
  58  *
  59  * If set, ACPI SCI is used to handle UIE/AIE and system wakeup
  60  */
  61
  62 static bool use_acpi_alarm;
  63 module_param(use_acpi_alarm, bool, 0444);
  64
  65 static inline int cmos_use_acpi_alarm(void)
  66 {
  67         return use_acpi_alarm;
  68 }
  69 #else /* !CONFIG_ACPI */
  70
  71 static inline int cmos_use_acpi_alarm(void)
  72 {
  73         return 0;
  74 }
  75 #endif
  76
  77 struct cmos_rtc {
  78         struct rtc_device       *rtc;
  79         struct device           *dev;
  80         int                     irq;
  81         struct resource         *iomem;
  82         time64_t                alarm_expires;
  83
  84         void                    (*wake_on)(struct device *);
  85         void                    (*wake_off)(struct device *);
  86
  87         u8                      enabled_wake;
  88         u8                      suspend_ctrl;
  89
  90         /* newer hardware extends the original register set */
  91         u8                      day_alrm;
  92         u8                      mon_alrm;
  93         u8                      century;
  94
  95         struct rtc_wkalrm       saved_wkalrm;
  96 };
  97
  98 /* both platform and pnp busses use negative numbers for invalid irqs */
  99 #define is_valid_irq(n)         ((n) > 0)
 100
 101 static const char driver_name[] = "rtc_cmos";
 102
 103 /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
 104  * always mask it against the irq enable bits in RTC_CONTROL.  Bit values
 105  * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
 106  */
 107 #define RTC_IRQMASK     (RTC_PF | RTC_AF | RTC_UF)
 108
 109 static inline int is_intr(u8 rtc_intr)
 110 {
 111         if (!(rtc_intr & RTC_IRQF))
 112                 return 0;
 113         return rtc_intr & RTC_IRQMASK;
 114 }
 115
 116 /*----------------------------------------------------------------*/
 117
 118 /* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
 119  * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
 120  * used in a broken "legacy replacement" mode.  The breakage includes
 121  * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
 122  * other (better) use.
 123  *
 124  * When that broken mode is in use, platform glue provides a partial
 125  * emulation of hardware RTC IRQ facilities using HPET #1.  We don't
 126  * want to use HPET for anything except those IRQs though...
 127  */
 128 #ifdef CONFIG_HPET_EMULATE_RTC
 129 #include <asm/hpet.h>
 130 #else
 131
 132 static inline int is_hpet_enabled(void)
 133 {
 134         return 0;
 135 }
 136
 137 static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
 138 {
 139         return 0;
 140 }
 141
 142 static inline int hpet_set_rtc_irq_bit(unsigned long mask)
 143 {
 144         return 0;
 145 }
 146
 147 static inline int
 148 hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
 149 {
 150         return 0;
 151 }
 152
 153 static inline int hpet_set_periodic_freq(unsigned long freq)
 154 {
 155         return 0;
 156 }
 157
 158 static inline int hpet_rtc_dropped_irq(void)
 159 {
 160         return 0;
 161 }
 162
 163 static inline int hpet_rtc_timer_init(void)
 164 {
 165         return 0;
 166 }
 167
 168 extern irq_handler_t hpet_rtc_interrupt;
 169
 170 static inline int hpet_register_irq_handler(irq_handler_t handler)
 171 {
 172         return 0;
 173 }
 174
 175 static inline int hpet_unregister_irq_handler(irq_handler_t handler)
 176 {
 177         return 0;
 178 }
 179
 180 #endif
 181
 182 /* Don't use HPET for RTC Alarm event if ACPI Fixed event is used */
 183 static inline int use_hpet_alarm(void)
 184 {
 185         return is_hpet_enabled() && !cmos_use_acpi_alarm();
 186 }
 187
 188 /*----------------------------------------------------------------*/
 189
 190 #ifdef RTC_PORT
 191
 192 /* Most newer x86 systems have two register banks, the first used
 193  * for RTC and NVRAM and the second only for NVRAM.  Caller must
 194  * own rtc_lock ... and we won't worry about access during NMI.
 195  */
 196 #define can_bank2       true
 197
 198 static inline unsigned char cmos_read_bank2(unsigned char addr)
 199 {
 200         outb(addr, RTC_PORT(2));
 201         return inb(RTC_PORT(3));
 202 }
 203
 204 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 205 {
 206         outb(addr, RTC_PORT(2));
 207         outb(val, RTC_PORT(3));
 208 }
 209
 210 #else
 211
 212 #define can_bank2       false
 213
 214 static inline unsigned char cmos_read_bank2(unsigned char addr)
 215 {
 216         return 0;
 217 }
 218
 219 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 220 {
 221 }
 222
 223 #endif
 224
 225 /*----------------------------------------------------------------*/
 226
 227 static int cmos_read_time(struct device *dev, struct rtc_time *t)
 228 {
 229         /*
 230          * If pm_trace abused the RTC for storage, set the timespec to 0,
 231          * which tells the caller that this RTC value is unusable.
 232          */
 233         if (!pm_trace_rtc_valid())
 234                 return -EIO;
 235
 236         /* REVISIT:  if the clock has a "century" register, use
 237          * that instead of the heuristic in mc146818_get_time().
 238          * That'll make Y3K compatility (year > 2070) easy!
 239          */
 240         mc146818_get_time(t);
 241         return 0;
 242 }
 243
 244 static int cmos_set_time(struct device *dev, struct rtc_time *t)
 245 {
 246         /* REVISIT:  set the "century" register if available
 247          *
 248          * NOTE: this ignores the issue whereby updating the seconds
 249          * takes effect exactly 500ms after we write the register.
 250          * (Also queueing and other delays before we get this far.)
 251          */
 252         return mc146818_set_time(t);
 253 }
 254
 255 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 256 {
 257         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 258         unsigned char   rtc_control;
 259
 260         if (!is_valid_irq(cmos->irq))
 261                 return -EIO;
 262
 263         /* Basic alarms only support hour, minute, and seconds fields.
 264          * Some also support day and month, for alarms up to a year in
 265          * the future.
 266          */
 267
 268         spin_lock_irq(&rtc_lock);
 269         t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
 270         t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
 271         t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 272
 273         if (cmos->day_alrm) {
 274                 /* ignore upper bits on readback per ACPI spec */
 275                 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
 276                 if (!t->time.tm_mday)
 277                         t->time.tm_mday = -1;
 278
 279                 if (cmos->mon_alrm) {
 280                         t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
 281                         if (!t->time.tm_mon)
 282                                 t->time.tm_mon = -1;
 283                 }
 284         }
 285
 286         rtc_control = CMOS_READ(RTC_CONTROL);
 287         spin_unlock_irq(&rtc_lock);
 288
 289         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 290                 if (((unsigned)t->time.tm_sec) < 0x60)
 291                         t->time.tm_sec = bcd2bin(t->time.tm_sec);
 292                 else
 293                         t->time.tm_sec = -1;
 294                 if (((unsigned)t->time.tm_min) < 0x60)
 295                         t->time.tm_min = bcd2bin(t->time.tm_min);
 296                 else
 297                         t->time.tm_min = -1;
 298                 if (((unsigned)t->time.tm_hour) < 0x24)
 299                         t->time.tm_hour = bcd2bin(t->time.tm_hour);
 300                 else
 301                         t->time.tm_hour = -1;
 302
 303                 if (cmos->day_alrm) {
 304                         if (((unsigned)t->time.tm_mday) <= 0x31)
 305                                 t->time.tm_mday = bcd2bin(t->time.tm_mday);
 306                         else
 307                                 t->time.tm_mday = -1;
 308
 309                         if (cmos->mon_alrm) {
 310                                 if (((unsigned)t->time.tm_mon) <= 0x12)
 311                                         t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
 312                                 else
 313                                         t->time.tm_mon = -1;
 314                         }
 315                 }
 316         }
 317
 318         t->enabled = !!(rtc_control & RTC_AIE);
 319         t->pending = 0;
 320
 321         return 0;
 322 }
 323
 324 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
 325 {
 326         unsigned char   rtc_intr;
 327
 328         /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
 329          * allegedly some older rtcs need that to handle irqs properly
 330          */
 331         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 332
 333         if (use_hpet_alarm())
 334                 return;
 335
 336         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 337         if (is_intr(rtc_intr))
 338                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
 339 }
 340
 341 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
 342 {
 343         unsigned char   rtc_control;
 344
 345         /* flush any pending IRQ status, notably for update irqs,
 346          * before we enable new IRQs
 347          */
 348         rtc_control = CMOS_READ(RTC_CONTROL);
 349         cmos_checkintr(cmos, rtc_control);
 350
 351         rtc_control |= mask;
 352         CMOS_WRITE(rtc_control, RTC_CONTROL);
 353         if (use_hpet_alarm())
 354                 hpet_set_rtc_irq_bit(mask);
 355
 356         if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
 357                 if (cmos->wake_on)
 358                         cmos->wake_on(cmos->dev);
 359         }
 360
 361         cmos_checkintr(cmos, rtc_control);
 362 }
 363
 364 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
 365 {
 366         unsigned char   rtc_control;
 367
 368         rtc_control = CMOS_READ(RTC_CONTROL);
 369         rtc_control &= ~mask;
 370         CMOS_WRITE(rtc_control, RTC_CONTROL);
 371         if (use_hpet_alarm())
 372                 hpet_mask_rtc_irq_bit(mask);
 373
 374         if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
 375                 if (cmos->wake_off)
 376                         cmos->wake_off(cmos->dev);
 377         }
 378
 379         cmos_checkintr(cmos, rtc_control);
 380 }
 381
 382 static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t)
 383 {
 384         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 385         struct rtc_time now;
 386
 387         cmos_read_time(dev, &now);
 388
 389         if (!cmos->day_alrm) {
 390                 time64_t t_max_date;
 391                 time64_t t_alrm;
 392
 393                 t_max_date = rtc_tm_to_time64(&now);
 394                 t_max_date += 24 * 60 * 60 - 1;
 395                 t_alrm = rtc_tm_to_time64(&t->time);
 396                 if (t_alrm > t_max_date) {
 397                         dev_err(dev,
 398                                 "Alarms can be up to one day in the future\n");
 399                         return -EINVAL;
 400                 }
 401         } else if (!cmos->mon_alrm) {
 402                 struct rtc_time max_date = now;
 403                 time64_t t_max_date;
 404                 time64_t t_alrm;
 405                 int max_mday;
 406
 407                 if (max_date.tm_mon == 11) {
 408                         max_date.tm_mon = 0;
 409                         max_date.tm_year += 1;
 410                 } else {
 411                         max_date.tm_mon += 1;
 412                 }
 413                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 414                 if (max_date.tm_mday > max_mday)
 415                         max_date.tm_mday = max_mday;
 416
 417                 t_max_date = rtc_tm_to_time64(&max_date);
 418                 t_max_date -= 1;
 419                 t_alrm = rtc_tm_to_time64(&t->time);
 420                 if (t_alrm > t_max_date) {
 421                         dev_err(dev,
 422                                 "Alarms can be up to one month in the future\n");
 423                         return -EINVAL;
 424                 }
 425         } else {
 426                 struct rtc_time max_date = now;
 427                 time64_t t_max_date;
 428                 time64_t t_alrm;
 429                 int max_mday;
 430
 431                 max_date.tm_year += 1;
 432                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 433                 if (max_date.tm_mday > max_mday)
 434                         max_date.tm_mday = max_mday;
 435
 436                 t_max_date = rtc_tm_to_time64(&max_date);
 437                 t_max_date -= 1;
 438                 t_alrm = rtc_tm_to_time64(&t->time);
 439                 if (t_alrm > t_max_date) {
 440                         dev_err(dev,
 441                                 "Alarms can be up to one year in the future\n");
 442                         return -EINVAL;
 443                 }
 444         }
 445
 446         return 0;
 447 }
 448
 449 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 450 {
 451         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 452         unsigned char mon, mday, hrs, min, sec, rtc_control;
 453         int ret;
 454
 455         if (!is_valid_irq(cmos->irq))
 456                 return -EIO;
 457
 458         ret = cmos_validate_alarm(dev, t);
 459         if (ret < 0)
 460                 return ret;
 461
 462         mon = t->time.tm_mon + 1;
 463         mday = t->time.tm_mday;
 464         hrs = t->time.tm_hour;
 465         min = t->time.tm_min;
 466         sec = t->time.tm_sec;
 467
 468         rtc_control = CMOS_READ(RTC_CONTROL);
 469         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 470                 /* Writing 0xff means "don't care" or "match all".  */
 471                 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
 472                 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 473                 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
 474                 min = (min < 60) ? bin2bcd(min) : 0xff;
 475                 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
 476         }
 477
 478         spin_lock_irq(&rtc_lock);
 479
 480         /* next rtc irq must not be from previous alarm setting */
 481         cmos_irq_disable(cmos, RTC_AIE);
 482
 483         /* update alarm */
 484         CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 485         CMOS_WRITE(min, RTC_MINUTES_ALARM);
 486         CMOS_WRITE(sec, RTC_SECONDS_ALARM);
 487
 488         /* the system may support an "enhanced" alarm */
 489         if (cmos->day_alrm) {
 490                 CMOS_WRITE(mday, cmos->day_alrm);
 491                 if (cmos->mon_alrm)
 492                         CMOS_WRITE(mon, cmos->mon_alrm);
 493         }
 494
 495         if (use_hpet_alarm()) {
 496                 /*
 497                  * FIXME the HPET alarm glue currently ignores day_alrm
 498                  * and mon_alrm ...
 499                  */
 500                 hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min,
 501                                     t->time.tm_sec);
 502         }
 503
 504         if (t->enabled)
 505                 cmos_irq_enable(cmos, RTC_AIE);
 506
 507         spin_unlock_irq(&rtc_lock);
 508
 509         cmos->alarm_expires = rtc_tm_to_time64(&t->time);
 510
 511         return 0;
 512 }
 513
 514 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 515 {
 516         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 517         unsigned long   flags;
 518
 519         if (!is_valid_irq(cmos->irq))
 520                 return -EINVAL;
 521
 522         spin_lock_irqsave(&rtc_lock, flags);
 523
 524         if (enabled)
 525                 cmos_irq_enable(cmos, RTC_AIE);
 526         else
 527                 cmos_irq_disable(cmos, RTC_AIE);
 528
 529         spin_unlock_irqrestore(&rtc_lock, flags);
 530         return 0;
 531 }
 532
 533 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 534
 535 static int cmos_procfs(struct device *dev, struct seq_file *seq)
 536 {
 537         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 538         unsigned char   rtc_control, valid;
 539
 540         spin_lock_irq(&rtc_lock);
 541         rtc_control = CMOS_READ(RTC_CONTROL);
 542         valid = CMOS_READ(RTC_VALID);
 543         spin_unlock_irq(&rtc_lock);
 544
 545         /* NOTE:  at least ICH6 reports battery status using a different
 546          * (non-RTC) bit; and SQWE is ignored on many current systems.
 547          */
 548         seq_printf(seq,
 549                    "periodic_IRQ\t: %s\n"
 550                    "update_IRQ\t: %s\n"
 551                    "HPET_emulated\t: %s\n"
 552                    // "square_wave\t: %s\n"
 553                    "BCD\t\t: %s\n"
 554                    "DST_enable\t: %s\n"
 555                    "periodic_freq\t: %d\n"
 556                    "batt_status\t: %s\n",
 557                    (rtc_control & RTC_PIE) ? "yes" : "no",
 558                    (rtc_control & RTC_UIE) ? "yes" : "no",
 559                    use_hpet_alarm() ? "yes" : "no",
 560                    // (rtc_control & RTC_SQWE) ? "yes" : "no",
 561                    (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 562                    (rtc_control & RTC_DST_EN) ? "yes" : "no",
 563                    cmos->rtc->irq_freq,
 564                    (valid & RTC_VRT) ? "okay" : "dead");
 565
 566         return 0;
 567 }
 568
 569 #else
 570 #define cmos_procfs     NULL
 571 #endif
 572
 573 static const struct rtc_class_ops cmos_rtc_ops = {
 574         .read_time              = cmos_read_time,
 575         .set_time               = cmos_set_time,
 576         .read_alarm             = cmos_read_alarm,
 577         .set_alarm              = cmos_set_alarm,
 578         .proc                   = cmos_procfs,
 579         .alarm_irq_enable       = cmos_alarm_irq_enable,
 580 };
 581
 582 /*----------------------------------------------------------------*/
 583
 584 /*
 585  * All these chips have at least 64 bytes of address space, shared by
 586  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 587  * by boot firmware.  Modern chips have 128 or 256 bytes.
 588  */
 589
 590 #define NVRAM_OFFSET    (RTC_REG_D + 1)
 591
 592 static int cmos_nvram_read(void *priv, unsigned int off, void *val,
 593                            size_t count)
 594 {
 595         unsigned char *buf = val;
 596         int     retval;
 597
 598         off += NVRAM_OFFSET;
 599         spin_lock_irq(&rtc_lock);
 600         for (retval = 0; count; count--, off++, retval++) {
 601                 if (off < 128)
 602                         *buf++ = CMOS_READ(off);
 603                 else if (can_bank2)
 604                         *buf++ = cmos_read_bank2(off);
 605                 else
 606                         break;
 607         }
 608         spin_unlock_irq(&rtc_lock);
 609
 610         return retval;
 611 }
 612
 613 static int cmos_nvram_write(void *priv, unsigned int off, void *val,
 614                             size_t count)
 615 {
 616         struct cmos_rtc *cmos = priv;
 617         unsigned char   *buf = val;
 618         int             retval;
 619
 620         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 621          * checksum on part of the NVRAM data.  That's currently ignored
 622          * here.  If userspace is smart enough to know what fields of
 623          * NVRAM to update, updating checksums is also part of its job.
 624          */
 625         off += NVRAM_OFFSET;
 626         spin_lock_irq(&rtc_lock);
 627         for (retval = 0; count; count--, off++, retval++) {
 628                 /* don't trash RTC registers */
 629                 if (off == cmos->day_alrm
 630                                 || off == cmos->mon_alrm
 631                                 || off == cmos->century)
 632                         buf++;
 633                 else if (off < 128)
 634                         CMOS_WRITE(*buf++, off);
 635                 else if (can_bank2)
 636                         cmos_write_bank2(*buf++, off);
 637                 else
 638                         break;
 639         }
 640         spin_unlock_irq(&rtc_lock);
 641
 642         return retval;
 643 }
 644
 645 /*----------------------------------------------------------------*/
 646
 647 static struct cmos_rtc  cmos_rtc;
 648
 649 static irqreturn_t cmos_interrupt(int irq, void *p)
 650 {
 651         u8              irqstat;
 652         u8              rtc_control;
 653
 654         spin_lock(&rtc_lock);
 655
 656         /* When the HPET interrupt handler calls us, the interrupt
 657          * status is passed as arg1 instead of the irq number.  But
 658          * always clear irq status, even when HPET is in the way.
 659          *
 660          * Note that HPET and RTC are almost certainly out of phase,
 661          * giving different IRQ status ...
 662          */
 663         irqstat = CMOS_READ(RTC_INTR_FLAGS);
 664         rtc_control = CMOS_READ(RTC_CONTROL);
 665         if (use_hpet_alarm())
 666                 irqstat = (unsigned long)irq & 0xF0;
 667
 668         /* If we were suspended, RTC_CONTROL may not be accurate since the
 669          * bios may have cleared it.
 670          */
 671         if (!cmos_rtc.suspend_ctrl)
 672                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 673         else
 674                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 675
 676         /* All Linux RTC alarms should be treated as if they were oneshot.
 677          * Similar code may be needed in system wakeup paths, in case the
 678          * alarm woke the system.
 679          */
 680         if (irqstat & RTC_AIE) {
 681                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 682                 rtc_control &= ~RTC_AIE;
 683                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 684                 if (use_hpet_alarm())
 685                         hpet_mask_rtc_irq_bit(RTC_AIE);
 686                 CMOS_READ(RTC_INTR_FLAGS);
 687         }
 688         spin_unlock(&rtc_lock);
 689
 690         if (is_intr(irqstat)) {
 691                 rtc_update_irq(p, 1, irqstat);
 692                 return IRQ_HANDLED;
 693         } else
 694                 return IRQ_NONE;
 695 }
 696
 697 #ifdef  CONFIG_PNP
 698 #define INITSECTION
 699
 700 #else
 701 #define INITSECTION     __init
 702 #endif
 703
 704 static int INITSECTION
 705 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 706 {
 707         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
 708         int                             retval = 0;
 709         unsigned char                   rtc_control;
 710         unsigned                        address_space;
 711         u32                             flags = 0;
 712         struct nvmem_config nvmem_cfg = {
 713                 .name = "cmos_nvram",
 714                 .word_size = 1,
 715                 .stride = 1,
 716                 .reg_read = cmos_nvram_read,
 717                 .reg_write = cmos_nvram_write,
 718                 .priv = &cmos_rtc,
 719         };
 720
 721         /* there can be only one ... */
 722         if (cmos_rtc.dev)
 723                 return -EBUSY;
 724
 725         if (!ports)
 726                 return -ENODEV;
 727
 728         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 729          *
 730          * REVISIT non-x86 systems may instead use memory space resources
 731          * (needing ioremap etc), not i/o space resources like this ...
 732          */
 733         if (RTC_IOMAPPED)
 734                 ports = request_region(ports->start, resource_size(ports),
 735                                        driver_name);
 736         else
 737                 ports = request_mem_region(ports->start, resource_size(ports),
 738                                            driver_name);
 739         if (!ports) {
 740                 dev_dbg(dev, "i/o registers already in use\n");
 741                 return -EBUSY;
 742         }
 743
 744         cmos_rtc.irq = rtc_irq;
 745         cmos_rtc.iomem = ports;
 746
 747         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 748          * driver did, but don't reject unknown configs.   Old hardware
 749          * won't address 128 bytes.  Newer chips have multiple banks,
 750          * though they may not be listed in one I/O resource.
 751          */
 752 #if     defined(CONFIG_ATARI)
 753         address_space = 64;
 754 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 755                         || defined(__sparc__) || defined(__mips__) \
 756                         || defined(__powerpc__)
 757         address_space = 128;
 758 #else
 759 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 760         address_space = 128;
 761 #endif
 762         if (can_bank2 && ports->end > (ports->start + 1))
 763                 address_space = 256;
 764
 765         /* For ACPI systems extension info comes from the FADT.  On others,
 766          * board specific setup provides it as appropriate.  Systems where
 767          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 768          * some almost-clones) can provide hooks to make that behave.
 769          *
 770          * Note that ACPI doesn't preclude putting these registers into
 771          * "extended" areas of the chip, including some that we won't yet
 772          * expect CMOS_READ and friends to handle.
 773          */
 774         if (info) {
 775                 if (info->flags)
 776                         flags = info->flags;
 777                 if (info->address_space)
 778                         address_space = info->address_space;
 779
 780                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
 781                         cmos_rtc.day_alrm = info->rtc_day_alarm;
 782                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
 783                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
 784                 if (info->rtc_century && info->rtc_century < 128)
 785                         cmos_rtc.century = info->rtc_century;
 786
 787                 if (info->wake_on && info->wake_off) {
 788                         cmos_rtc.wake_on = info->wake_on;
 789                         cmos_rtc.wake_off = info->wake_off;
 790                 }
 791         }
 792
 793         cmos_rtc.dev = dev;
 794         dev_set_drvdata(dev, &cmos_rtc);
 795
 796         cmos_rtc.rtc = devm_rtc_allocate_device(dev);
 797         if (IS_ERR(cmos_rtc.rtc)) {
 798                 retval = PTR_ERR(cmos_rtc.rtc);
 799                 goto cleanup0;
 800         }
 801
 802         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 803
 804         spin_lock_irq(&rtc_lock);
 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                                 IRQF_SHARED, 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         }
 859
 860         cmos_rtc.rtc->ops = &cmos_rtc_ops;
 861         cmos_rtc.rtc->nvram_old_abi = true;
 862         retval = rtc_register_device(cmos_rtc.rtc);
 863         if (retval)
 864                 goto cleanup2;
 865
 866         /* export at least the first block of NVRAM */
 867         nvmem_cfg.size = address_space - NVRAM_OFFSET;
 868         if (rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg))
 869                 dev_err(dev, "nvmem registration failed\n");
 870
 871         dev_info(dev, "%s%s, %d bytes nvram%s\n",
 872                  !is_valid_irq(rtc_irq) ? "no alarms" :
 873                  cmos_rtc.mon_alrm ? "alarms up to one year" :
 874                  cmos_rtc.day_alrm ? "alarms up to one month" :
 875                  "alarms up to one day",
 876                  cmos_rtc.century ? ", y3k" : "",
 877                  nvmem_cfg.size,
 878                  use_hpet_alarm() ? ", hpet irqs" : "");
 879
 880         return 0;
 881
 882 cleanup2:
 883         if (is_valid_irq(rtc_irq))
 884                 free_irq(rtc_irq, cmos_rtc.rtc);
 885 cleanup1:
 886         cmos_rtc.dev = NULL;
 887 cleanup0:
 888         if (RTC_IOMAPPED)
 889                 release_region(ports->start, resource_size(ports));
 890         else
 891                 release_mem_region(ports->start, resource_size(ports));
 892         return retval;
 893 }
 894
 895 static void cmos_do_shutdown(int rtc_irq)
 896 {
 897         spin_lock_irq(&rtc_lock);
 898         if (is_valid_irq(rtc_irq))
 899                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
 900         spin_unlock_irq(&rtc_lock);
 901 }
 902
 903 static void cmos_do_remove(struct device *dev)
 904 {
 905         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 906         struct resource *ports;
 907
 908         cmos_do_shutdown(cmos->irq);
 909
 910         if (is_valid_irq(cmos->irq)) {
 911                 free_irq(cmos->irq, cmos->rtc);
 912                 if (use_hpet_alarm())
 913                         hpet_unregister_irq_handler(cmos_interrupt);
 914         }
 915
 916         cmos->rtc = NULL;
 917
 918         ports = cmos->iomem;
 919         if (RTC_IOMAPPED)
 920                 release_region(ports->start, resource_size(ports));
 921         else
 922                 release_mem_region(ports->start, resource_size(ports));
 923         cmos->iomem = NULL;
 924
 925         cmos->dev = NULL;
 926 }
 927
 928 static int cmos_aie_poweroff(struct device *dev)
 929 {
 930         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 931         struct rtc_time now;
 932         time64_t t_now;
 933         int retval = 0;
 934         unsigned char rtc_control;
 935
 936         if (!cmos->alarm_expires)
 937                 return -EINVAL;
 938
 939         spin_lock_irq(&rtc_lock);
 940         rtc_control = CMOS_READ(RTC_CONTROL);
 941         spin_unlock_irq(&rtc_lock);
 942
 943         /* We only care about the situation where AIE is disabled. */
 944         if (rtc_control & RTC_AIE)
 945                 return -EBUSY;
 946
 947         cmos_read_time(dev, &now);
 948         t_now = rtc_tm_to_time64(&now);
 949
 950         /*
 951          * When enabling "RTC wake-up" in BIOS setup, the machine reboots
 952          * automatically right after shutdown on some buggy boxes.
 953          * This automatic rebooting issue won't happen when the alarm
 954          * time is larger than now+1 seconds.
 955          *
 956          * If the alarm time is equal to now+1 seconds, the issue can be
 957          * prevented by cancelling the alarm.
 958          */
 959         if (cmos->alarm_expires == t_now + 1) {
 960                 struct rtc_wkalrm alarm;
 961
 962                 /* Cancel the AIE timer by configuring the past time. */
 963                 rtc_time64_to_tm(t_now - 1, &alarm.time);
 964                 alarm.enabled = 0;
 965                 retval = cmos_set_alarm(dev, &alarm);
 966         } else if (cmos->alarm_expires > t_now + 1) {
 967                 retval = -EBUSY;
 968         }
 969
 970         return retval;
 971 }
 972
 973 static int cmos_suspend(struct device *dev)
 974 {
 975         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 976         unsigned char   tmp;
 977
 978         /* only the alarm might be a wakeup event source */
 979         spin_lock_irq(&rtc_lock);
 980         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
 981         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 982                 unsigned char   mask;
 983
 984                 if (device_may_wakeup(dev))
 985                         mask = RTC_IRQMASK & ~RTC_AIE;
 986                 else
 987                         mask = RTC_IRQMASK;
 988                 tmp &= ~mask;
 989                 CMOS_WRITE(tmp, RTC_CONTROL);
 990                 if (use_hpet_alarm())
 991                         hpet_mask_rtc_irq_bit(mask);
 992                 cmos_checkintr(cmos, tmp);
 993         }
 994         spin_unlock_irq(&rtc_lock);
 995
 996         if ((tmp & RTC_AIE) && !cmos_use_acpi_alarm()) {
 997                 cmos->enabled_wake = 1;
 998                 if (cmos->wake_on)
 999                         cmos->wake_on(dev);
1000                 else
1001                         enable_irq_wake(cmos->irq);
1002         }
1003
1004         cmos_read_alarm(dev, &cmos->saved_wkalrm);
1005
1006         dev_dbg(dev, "suspend%s, ctrl %02x\n",
1007                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
1008                         tmp);
1009
1010         return 0;
1011 }
1012
1013 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
1014  * after a detour through G3 "mechanical off", although the ACPI spec
1015  * says wakeup should only work from G1/S4 "hibernate".  To most users,
1016  * distinctions between S4 and S5 are pointless.  So when the hardware
1017  * allows, don't draw that distinction.
1018  */
1019 static inline int cmos_poweroff(struct device *dev)
1020 {
1021         if (!IS_ENABLED(CONFIG_PM))
1022                 return -ENOSYS;
1023
1024         return cmos_suspend(dev);
1025 }
1026
1027 static void cmos_check_wkalrm(struct device *dev)
1028 {
1029         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1030         struct rtc_wkalrm current_alarm;
1031         time64_t t_now;
1032         time64_t t_current_expires;
1033         time64_t t_saved_expires;
1034         struct rtc_time now;
1035
1036         /* Check if we have RTC Alarm armed */
1037         if (!(cmos->suspend_ctrl & RTC_AIE))
1038                 return;
1039
1040         cmos_read_time(dev, &now);
1041         t_now = rtc_tm_to_time64(&now);
1042
1043         /*
1044          * ACPI RTC wake event is cleared after resume from STR,
1045          * ACK the rtc irq here
1046          */
1047         if (t_now >= cmos->alarm_expires && cmos_use_acpi_alarm()) {
1048                 cmos_interrupt(0, (void *)cmos->rtc);
1049                 return;
1050         }
1051
1052         cmos_read_alarm(dev, &current_alarm);
1053         t_current_expires = rtc_tm_to_time64(&current_alarm.time);
1054         t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
1055         if (t_current_expires != t_saved_expires ||
1056             cmos->saved_wkalrm.enabled != current_alarm.enabled) {
1057                 cmos_set_alarm(dev, &cmos->saved_wkalrm);
1058         }
1059 }
1060
1061 static void cmos_check_acpi_rtc_status(struct device *dev,
1062                                        unsigned char *rtc_control);
1063
1064 static int __maybe_unused cmos_resume(struct device *dev)
1065 {
1066         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1067         unsigned char tmp;
1068
1069         if (cmos->enabled_wake && !cmos_use_acpi_alarm()) {
1070                 if (cmos->wake_off)
1071                         cmos->wake_off(dev);
1072                 else
1073                         disable_irq_wake(cmos->irq);
1074                 cmos->enabled_wake = 0;
1075         }
1076
1077         /* The BIOS might have changed the alarm, restore it */
1078         cmos_check_wkalrm(dev);
1079
1080         spin_lock_irq(&rtc_lock);
1081         tmp = cmos->suspend_ctrl;
1082         cmos->suspend_ctrl = 0;
1083         /* re-enable any irqs previously active */
1084         if (tmp & RTC_IRQMASK) {
1085                 unsigned char   mask;
1086
1087                 if (device_may_wakeup(dev) && use_hpet_alarm())
1088                         hpet_rtc_timer_init();
1089
1090                 do {
1091                         CMOS_WRITE(tmp, RTC_CONTROL);
1092                         if (use_hpet_alarm())
1093                                 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1094
1095                         mask = CMOS_READ(RTC_INTR_FLAGS);
1096                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1097                         if (!use_hpet_alarm() || !is_intr(mask))
1098                                 break;
1099
1100                         /* force one-shot behavior if HPET blocked
1101                          * the wake alarm's irq
1102                          */
1103                         rtc_update_irq(cmos->rtc, 1, mask);
1104                         tmp &= ~RTC_AIE;
1105                         hpet_mask_rtc_irq_bit(RTC_AIE);
1106                 } while (mask & RTC_AIE);
1107
1108                 if (tmp & RTC_AIE)
1109                         cmos_check_acpi_rtc_status(dev, &tmp);
1110         }
1111         spin_unlock_irq(&rtc_lock);
1112
1113         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1114
1115         return 0;
1116 }
1117
1118 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1119
1120 /*----------------------------------------------------------------*/
1121
1122 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1123  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1124  * probably list them in similar PNPBIOS tables; so PNP is more common.
1125  *
1126  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1127  * predate even PNPBIOS should set up platform_bus devices.
1128  */
1129
1130 #ifdef  CONFIG_ACPI
1131
1132 #include <linux/acpi.h>
1133
1134 static u32 rtc_handler(void *context)
1135 {
1136         struct device *dev = context;
1137         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1138         unsigned char rtc_control = 0;
1139         unsigned char rtc_intr;
1140         unsigned long flags;
1141
1142
1143         /*
1144          * Always update rtc irq when ACPI is used as RTC Alarm.
1145          * Or else, ACPI SCI is enabled during suspend/resume only,
1146          * update rtc irq in that case.
1147          */
1148         if (cmos_use_acpi_alarm())
1149                 cmos_interrupt(0, (void *)cmos->rtc);
1150         else {
1151                 /* Fix me: can we use cmos_interrupt() here as well? */
1152                 spin_lock_irqsave(&rtc_lock, flags);
1153                 if (cmos_rtc.suspend_ctrl)
1154                         rtc_control = CMOS_READ(RTC_CONTROL);
1155                 if (rtc_control & RTC_AIE) {
1156                         cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1157                         CMOS_WRITE(rtc_control, RTC_CONTROL);
1158                         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1159                         rtc_update_irq(cmos->rtc, 1, rtc_intr);
1160                 }
1161                 spin_unlock_irqrestore(&rtc_lock, flags);
1162         }
1163
1164         pm_wakeup_hard_event(dev);
1165         acpi_clear_event(ACPI_EVENT_RTC);
1166         acpi_disable_event(ACPI_EVENT_RTC, 0);
1167         return ACPI_INTERRUPT_HANDLED;
1168 }
1169
1170 static inline void rtc_wake_setup(struct device *dev)
1171 {
1172         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1173         /*
1174          * After the RTC handler is installed, the Fixed_RTC event should
1175          * be disabled. Only when the RTC alarm is set will it be enabled.
1176          */
1177         acpi_clear_event(ACPI_EVENT_RTC);
1178         acpi_disable_event(ACPI_EVENT_RTC, 0);
1179 }
1180
1181 static void rtc_wake_on(struct device *dev)
1182 {
1183         acpi_clear_event(ACPI_EVENT_RTC);
1184         acpi_enable_event(ACPI_EVENT_RTC, 0);
1185 }
1186
1187 static void rtc_wake_off(struct device *dev)
1188 {
1189         acpi_disable_event(ACPI_EVENT_RTC, 0);
1190 }
1191
1192 #ifdef CONFIG_X86
1193 /* Enable use_acpi_alarm mode for Intel platforms no earlier than 2015 */
1194 static void use_acpi_alarm_quirks(void)
1195 {
1196         int year;
1197
1198         if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
1199                 return;
1200
1201         if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
1202                 return;
1203
1204         if (!is_hpet_enabled())
1205                 return;
1206
1207         if (dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL) && year >= 2015)
1208                 use_acpi_alarm = true;
1209 }
1210 #else
1211 static inline void use_acpi_alarm_quirks(void) { }
1212 #endif
1213
1214 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1215  * its device node and pass extra config data.  This helps its driver use
1216  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1217  * that this board's RTC is wakeup-capable (per ACPI spec).
1218  */
1219 static struct cmos_rtc_board_info acpi_rtc_info;
1220
1221 static void cmos_wake_setup(struct device *dev)
1222 {
1223         if (acpi_disabled)
1224                 return;
1225
1226         use_acpi_alarm_quirks();
1227
1228         rtc_wake_setup(dev);
1229         acpi_rtc_info.wake_on = rtc_wake_on;
1230         acpi_rtc_info.wake_off = rtc_wake_off;
1231
1232         /* workaround bug in some ACPI tables */
1233         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1234                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1235                         acpi_gbl_FADT.month_alarm);
1236                 acpi_gbl_FADT.month_alarm = 0;
1237         }
1238
1239         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1240         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1241         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1242
1243         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1244         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1245                 dev_info(dev, "RTC can wake from S4\n");
1246
1247         dev->platform_data = &acpi_rtc_info;
1248
1249         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1250         device_init_wakeup(dev, 1);
1251 }
1252
1253 static void cmos_check_acpi_rtc_status(struct device *dev,
1254                                        unsigned char *rtc_control)
1255 {
1256         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1257         acpi_event_status rtc_status;
1258         acpi_status status;
1259
1260         if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1261                 return;
1262
1263         status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1264         if (ACPI_FAILURE(status)) {
1265                 dev_err(dev, "Could not get RTC status\n");
1266         } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1267                 unsigned char mask;
1268                 *rtc_control &= ~RTC_AIE;
1269                 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1270                 mask = CMOS_READ(RTC_INTR_FLAGS);
1271                 rtc_update_irq(cmos->rtc, 1, mask);
1272         }
1273 }
1274
1275 #else
1276
1277 static void cmos_wake_setup(struct device *dev)
1278 {
1279 }
1280
1281 static void cmos_check_acpi_rtc_status(struct device *dev,
1282                                        unsigned char *rtc_control)
1283 {
1284 }
1285
1286 #endif
1287
1288 #ifdef  CONFIG_PNP
1289
1290 #include <linux/pnp.h>
1291
1292 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1293 {
1294         cmos_wake_setup(&pnp->dev);
1295
1296         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1297                 unsigned int irq = 0;
1298 #ifdef CONFIG_X86
1299                 /* Some machines contain a PNP entry for the RTC, but
1300                  * don't define the IRQ. It should always be safe to
1301                  * hardcode it on systems with a legacy PIC.
1302                  */
1303                 if (nr_legacy_irqs())
1304                         irq = 8;
1305 #endif
1306                 return cmos_do_probe(&pnp->dev,
1307                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1308         } else {
1309                 return cmos_do_probe(&pnp->dev,
1310                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1311                                 pnp_irq(pnp, 0));
1312         }
1313 }
1314
1315 static void cmos_pnp_remove(struct pnp_dev *pnp)
1316 {
1317         cmos_do_remove(&pnp->dev);
1318 }
1319
1320 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1321 {
1322         struct device *dev = &pnp->dev;
1323         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1324
1325         if (system_state == SYSTEM_POWER_OFF) {
1326                 int retval = cmos_poweroff(dev);
1327
1328                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1329                         return;
1330         }
1331
1332         cmos_do_shutdown(cmos->irq);
1333 }
1334
1335 static const struct pnp_device_id rtc_ids[] = {
1336         { .id = "PNP0b00", },
1337         { .id = "PNP0b01", },
1338         { .id = "PNP0b02", },
1339         { },
1340 };
1341 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1342
1343 static struct pnp_driver cmos_pnp_driver = {
1344         .name           = (char *) driver_name,
1345         .id_table       = rtc_ids,
1346         .probe          = cmos_pnp_probe,
1347         .remove         = cmos_pnp_remove,
1348         .shutdown       = cmos_pnp_shutdown,
1349
1350         /* flag ensures resume() gets called, and stops syslog spam */
1351         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1352         .driver         = {
1353                         .pm = &cmos_pm_ops,
1354         },
1355 };
1356
1357 #endif  /* CONFIG_PNP */
1358
1359 #ifdef CONFIG_OF
1360 static const struct of_device_id of_cmos_match[] = {
1361         {
1362                 .compatible = "motorola,mc146818",
1363         },
1364         { },
1365 };
1366 MODULE_DEVICE_TABLE(of, of_cmos_match);
1367
1368 static __init void cmos_of_init(struct platform_device *pdev)
1369 {
1370         struct device_node *node = pdev->dev.of_node;
1371         const __be32 *val;
1372
1373         if (!node)
1374                 return;
1375
1376         val = of_get_property(node, "ctrl-reg", NULL);
1377         if (val)
1378                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1379
1380         val = of_get_property(node, "freq-reg", NULL);
1381         if (val)
1382                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1383 }
1384 #else
1385 static inline void cmos_of_init(struct platform_device *pdev) {}
1386 #endif
1387 /*----------------------------------------------------------------*/
1388
1389 /* Platform setup should have set up an RTC device, when PNP is
1390  * unavailable ... this could happen even on (older) PCs.
1391  */
1392
1393 static int __init cmos_platform_probe(struct platform_device *pdev)
1394 {
1395         struct resource *resource;
1396         int irq;
1397
1398         cmos_of_init(pdev);
1399         cmos_wake_setup(&pdev->dev);
1400
1401         if (RTC_IOMAPPED)
1402                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1403         else
1404                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1405         irq = platform_get_irq(pdev, 0);
1406         if (irq < 0)
1407                 irq = -1;
1408
1409         return cmos_do_probe(&pdev->dev, resource, irq);
1410 }
1411
1412 static int cmos_platform_remove(struct platform_device *pdev)
1413 {
1414         cmos_do_remove(&pdev->dev);
1415         return 0;
1416 }
1417
1418 static void cmos_platform_shutdown(struct platform_device *pdev)
1419 {
1420         struct device *dev = &pdev->dev;
1421         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1422
1423         if (system_state == SYSTEM_POWER_OFF) {
1424                 int retval = cmos_poweroff(dev);
1425
1426                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1427                         return;
1428         }
1429
1430         cmos_do_shutdown(cmos->irq);
1431 }
1432
1433 /* work with hotplug and coldplug */
1434 MODULE_ALIAS("platform:rtc_cmos");
1435
1436 static struct platform_driver cmos_platform_driver = {
1437         .remove         = cmos_platform_remove,
1438         .shutdown       = cmos_platform_shutdown,
1439         .driver = {
1440                 .name           = driver_name,
1441                 .pm             = &cmos_pm_ops,
1442                 .of_match_table = of_match_ptr(of_cmos_match),
1443         }
1444 };
1445
1446 #ifdef CONFIG_PNP
1447 static bool pnp_driver_registered;
1448 #endif
1449 static bool platform_driver_registered;
1450
1451 static int __init cmos_init(void)
1452 {
1453         int retval = 0;
1454
1455 #ifdef  CONFIG_PNP
1456         retval = pnp_register_driver(&cmos_pnp_driver);
1457         if (retval == 0)
1458                 pnp_driver_registered = true;
1459 #endif
1460
1461         if (!cmos_rtc.dev) {
1462                 retval = platform_driver_probe(&cmos_platform_driver,
1463                                                cmos_platform_probe);
1464                 if (retval == 0)
1465                         platform_driver_registered = true;
1466         }
1467
1468         if (retval == 0)
1469                 return 0;
1470
1471 #ifdef  CONFIG_PNP
1472         if (pnp_driver_registered)
1473                 pnp_unregister_driver(&cmos_pnp_driver);
1474 #endif
1475         return retval;
1476 }
1477 module_init(cmos_init);
1478
1479 static void __exit cmos_exit(void)
1480 {
1481 #ifdef  CONFIG_PNP
1482         if (pnp_driver_registered)
1483                 pnp_unregister_driver(&cmos_pnp_driver);
1484 #endif
1485         if (platform_driver_registered)
1486                 platform_driver_unregister(&cmos_platform_driver);
1487 }
1488 module_exit(cmos_exit);
1489
1490
1491 MODULE_AUTHOR("David Brownell");
1492 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1493 MODULE_LICENSE("GPL");