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         rtc_control = CMOS_READ(RTC_CONTROL);
 461         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 462                 /* Writing 0xff means "don't care" or "match all".  */
 463                 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
 464                 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 465                 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
 466                 min = (min < 60) ? bin2bcd(min) : 0xff;
 467                 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
 468         }
 469
 470         spin_lock_irq(&rtc_lock);
 471
 472         /* next rtc irq must not be from previous alarm setting */
 473         cmos_irq_disable(cmos, RTC_AIE);
 474
 475         /* update alarm */
 476         CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 477         CMOS_WRITE(min, RTC_MINUTES_ALARM);
 478         CMOS_WRITE(sec, RTC_SECONDS_ALARM);
 479
 480         /* the system may support an "enhanced" alarm */
 481         if (cmos->day_alrm) {
 482                 CMOS_WRITE(mday, cmos->day_alrm);
 483                 if (cmos->mon_alrm)
 484                         CMOS_WRITE(mon, cmos->mon_alrm);
 485         }
 486
 487         if (use_hpet_alarm()) {
 488                 /*
 489                  * FIXME the HPET alarm glue currently ignores day_alrm
 490                  * and mon_alrm ...
 491                  */
 492                 hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min,
 493                                     t->time.tm_sec);
 494         }
 495
 496         if (t->enabled)
 497                 cmos_irq_enable(cmos, RTC_AIE);
 498
 499         spin_unlock_irq(&rtc_lock);
 500
 501         cmos->alarm_expires = rtc_tm_to_time64(&t->time);
 502
 503         return 0;
 504 }
 505
 506 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 507 {
 508         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 509         unsigned long   flags;
 510
 511         spin_lock_irqsave(&rtc_lock, flags);
 512
 513         if (enabled)
 514                 cmos_irq_enable(cmos, RTC_AIE);
 515         else
 516                 cmos_irq_disable(cmos, RTC_AIE);
 517
 518         spin_unlock_irqrestore(&rtc_lock, flags);
 519         return 0;
 520 }
 521
 522 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 523
 524 static int cmos_procfs(struct device *dev, struct seq_file *seq)
 525 {
 526         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 527         unsigned char   rtc_control, valid;
 528
 529         spin_lock_irq(&rtc_lock);
 530         rtc_control = CMOS_READ(RTC_CONTROL);
 531         valid = CMOS_READ(RTC_VALID);
 532         spin_unlock_irq(&rtc_lock);
 533
 534         /* NOTE:  at least ICH6 reports battery status using a different
 535          * (non-RTC) bit; and SQWE is ignored on many current systems.
 536          */
 537         seq_printf(seq,
 538                    "periodic_IRQ\t: %s\n"
 539                    "update_IRQ\t: %s\n"
 540                    "HPET_emulated\t: %s\n"
 541                    // "square_wave\t: %s\n"
 542                    "BCD\t\t: %s\n"
 543                    "DST_enable\t: %s\n"
 544                    "periodic_freq\t: %d\n"
 545                    "batt_status\t: %s\n",
 546                    (rtc_control & RTC_PIE) ? "yes" : "no",
 547                    (rtc_control & RTC_UIE) ? "yes" : "no",
 548                    use_hpet_alarm() ? "yes" : "no",
 549                    // (rtc_control & RTC_SQWE) ? "yes" : "no",
 550                    (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 551                    (rtc_control & RTC_DST_EN) ? "yes" : "no",
 552                    cmos->rtc->irq_freq,
 553                    (valid & RTC_VRT) ? "okay" : "dead");
 554
 555         return 0;
 556 }
 557
 558 #else
 559 #define cmos_procfs     NULL
 560 #endif
 561
 562 static const struct rtc_class_ops cmos_rtc_ops = {
 563         .read_time              = cmos_read_time,
 564         .set_time               = cmos_set_time,
 565         .read_alarm             = cmos_read_alarm,
 566         .set_alarm              = cmos_set_alarm,
 567         .proc                   = cmos_procfs,
 568         .alarm_irq_enable       = cmos_alarm_irq_enable,
 569 };
 570
 571 /*----------------------------------------------------------------*/
 572
 573 /*
 574  * All these chips have at least 64 bytes of address space, shared by
 575  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 576  * by boot firmware.  Modern chips have 128 or 256 bytes.
 577  */
 578
 579 #define NVRAM_OFFSET    (RTC_REG_D + 1)
 580
 581 static int cmos_nvram_read(void *priv, unsigned int off, void *val,
 582                            size_t count)
 583 {
 584         unsigned char *buf = val;
 585         int     retval;
 586
 587         off += NVRAM_OFFSET;
 588         spin_lock_irq(&rtc_lock);
 589         for (retval = 0; count; count--, off++, retval++) {
 590                 if (off < 128)
 591                         *buf++ = CMOS_READ(off);
 592                 else if (can_bank2)
 593                         *buf++ = cmos_read_bank2(off);
 594                 else
 595                         break;
 596         }
 597         spin_unlock_irq(&rtc_lock);
 598
 599         return retval;
 600 }
 601
 602 static int cmos_nvram_write(void *priv, unsigned int off, void *val,
 603                             size_t count)
 604 {
 605         struct cmos_rtc *cmos = priv;
 606         unsigned char   *buf = val;
 607         int             retval;
 608
 609         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 610          * checksum on part of the NVRAM data.  That's currently ignored
 611          * here.  If userspace is smart enough to know what fields of
 612          * NVRAM to update, updating checksums is also part of its job.
 613          */
 614         off += NVRAM_OFFSET;
 615         spin_lock_irq(&rtc_lock);
 616         for (retval = 0; count; count--, off++, retval++) {
 617                 /* don't trash RTC registers */
 618                 if (off == cmos->day_alrm
 619                                 || off == cmos->mon_alrm
 620                                 || off == cmos->century)
 621                         buf++;
 622                 else if (off < 128)
 623                         CMOS_WRITE(*buf++, off);
 624                 else if (can_bank2)
 625                         cmos_write_bank2(*buf++, off);
 626                 else
 627                         break;
 628         }
 629         spin_unlock_irq(&rtc_lock);
 630
 631         return retval;
 632 }
 633
 634 /*----------------------------------------------------------------*/
 635
 636 static struct cmos_rtc  cmos_rtc;
 637
 638 static irqreturn_t cmos_interrupt(int irq, void *p)
 639 {
 640         u8              irqstat;
 641         u8              rtc_control;
 642
 643         spin_lock(&rtc_lock);
 644
 645         /* When the HPET interrupt handler calls us, the interrupt
 646          * status is passed as arg1 instead of the irq number.  But
 647          * always clear irq status, even when HPET is in the way.
 648          *
 649          * Note that HPET and RTC are almost certainly out of phase,
 650          * giving different IRQ status ...
 651          */
 652         irqstat = CMOS_READ(RTC_INTR_FLAGS);
 653         rtc_control = CMOS_READ(RTC_CONTROL);
 654         if (use_hpet_alarm())
 655                 irqstat = (unsigned long)irq & 0xF0;
 656
 657         /* If we were suspended, RTC_CONTROL may not be accurate since the
 658          * bios may have cleared it.
 659          */
 660         if (!cmos_rtc.suspend_ctrl)
 661                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 662         else
 663                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 664
 665         /* All Linux RTC alarms should be treated as if they were oneshot.
 666          * Similar code may be needed in system wakeup paths, in case the
 667          * alarm woke the system.
 668          */
 669         if (irqstat & RTC_AIE) {
 670                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 671                 rtc_control &= ~RTC_AIE;
 672                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 673                 if (use_hpet_alarm())
 674                         hpet_mask_rtc_irq_bit(RTC_AIE);
 675                 CMOS_READ(RTC_INTR_FLAGS);
 676         }
 677         spin_unlock(&rtc_lock);
 678
 679         if (is_intr(irqstat)) {
 680                 rtc_update_irq(p, 1, irqstat);
 681                 return IRQ_HANDLED;
 682         } else
 683                 return IRQ_NONE;
 684 }
 685
 686 #ifdef  CONFIG_PNP
 687 #define INITSECTION
 688
 689 #else
 690 #define INITSECTION     __init
 691 #endif
 692
 693 static int INITSECTION
 694 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 695 {
 696         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
 697         int                             retval = 0;
 698         unsigned char                   rtc_control;
 699         unsigned                        address_space;
 700         u32                             flags = 0;
 701         struct nvmem_config nvmem_cfg = {
 702                 .name = "cmos_nvram",
 703                 .word_size = 1,
 704                 .stride = 1,
 705                 .reg_read = cmos_nvram_read,
 706                 .reg_write = cmos_nvram_write,
 707                 .priv = &cmos_rtc,
 708         };
 709
 710         /* there can be only one ... */
 711         if (cmos_rtc.dev)
 712                 return -EBUSY;
 713
 714         if (!ports)
 715                 return -ENODEV;
 716
 717         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 718          *
 719          * REVISIT non-x86 systems may instead use memory space resources
 720          * (needing ioremap etc), not i/o space resources like this ...
 721          */
 722         if (RTC_IOMAPPED)
 723                 ports = request_region(ports->start, resource_size(ports),
 724                                        driver_name);
 725         else
 726                 ports = request_mem_region(ports->start, resource_size(ports),
 727                                            driver_name);
 728         if (!ports) {
 729                 dev_dbg(dev, "i/o registers already in use\n");
 730                 return -EBUSY;
 731         }
 732
 733         cmos_rtc.irq = rtc_irq;
 734         cmos_rtc.iomem = ports;
 735
 736         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 737          * driver did, but don't reject unknown configs.   Old hardware
 738          * won't address 128 bytes.  Newer chips have multiple banks,
 739          * though they may not be listed in one I/O resource.
 740          */
 741 #if     defined(CONFIG_ATARI)
 742         address_space = 64;
 743 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 744                         || defined(__sparc__) || defined(__mips__) \
 745                         || defined(__powerpc__)
 746         address_space = 128;
 747 #else
 748 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 749         address_space = 128;
 750 #endif
 751         if (can_bank2 && ports->end > (ports->start + 1))
 752                 address_space = 256;
 753
 754         /* For ACPI systems extension info comes from the FADT.  On others,
 755          * board specific setup provides it as appropriate.  Systems where
 756          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 757          * some almost-clones) can provide hooks to make that behave.
 758          *
 759          * Note that ACPI doesn't preclude putting these registers into
 760          * "extended" areas of the chip, including some that we won't yet
 761          * expect CMOS_READ and friends to handle.
 762          */
 763         if (info) {
 764                 if (info->flags)
 765                         flags = info->flags;
 766                 if (info->address_space)
 767                         address_space = info->address_space;
 768
 769                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
 770                         cmos_rtc.day_alrm = info->rtc_day_alarm;
 771                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
 772                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
 773                 if (info->rtc_century && info->rtc_century < 128)
 774                         cmos_rtc.century = info->rtc_century;
 775
 776                 if (info->wake_on && info->wake_off) {
 777                         cmos_rtc.wake_on = info->wake_on;
 778                         cmos_rtc.wake_off = info->wake_off;
 779                 }
 780         }
 781
 782         cmos_rtc.dev = dev;
 783         dev_set_drvdata(dev, &cmos_rtc);
 784
 785         cmos_rtc.rtc = devm_rtc_allocate_device(dev);
 786         if (IS_ERR(cmos_rtc.rtc)) {
 787                 retval = PTR_ERR(cmos_rtc.rtc);
 788                 goto cleanup0;
 789         }
 790
 791         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 792
 793         spin_lock_irq(&rtc_lock);
 794
 795         /* Ensure that the RTC is accessible. Bit 6 must be 0! */
 796         if ((CMOS_READ(RTC_VALID) & 0x40) != 0) {
 797                 spin_unlock_irq(&rtc_lock);
 798                 dev_warn(dev, "not accessible\n");
 799                 retval = -ENXIO;
 800                 goto cleanup1;
 801         }
 802
 803         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
 804                 /* force periodic irq to CMOS reset default of 1024Hz;
 805                  *
 806                  * REVISIT it's been reported that at least one x86_64 ALI
 807                  * mobo doesn't use 32KHz here ... for portability we might
 808                  * need to do something about other clock frequencies.
 809                  */
 810                 cmos_rtc.rtc->irq_freq = 1024;
 811                 if (use_hpet_alarm())
 812                         hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
 813                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
 814         }
 815
 816         /* disable irqs */
 817         if (is_valid_irq(rtc_irq))
 818                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
 819
 820         rtc_control = CMOS_READ(RTC_CONTROL);
 821
 822         spin_unlock_irq(&rtc_lock);
 823
 824         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
 825                 dev_warn(dev, "only 24-hr supported\n");
 826                 retval = -ENXIO;
 827                 goto cleanup1;
 828         }
 829
 830         if (use_hpet_alarm())
 831                 hpet_rtc_timer_init();
 832
 833         if (is_valid_irq(rtc_irq)) {
 834                 irq_handler_t rtc_cmos_int_handler;
 835
 836                 if (use_hpet_alarm()) {
 837                         rtc_cmos_int_handler = hpet_rtc_interrupt;
 838                         retval = hpet_register_irq_handler(cmos_interrupt);
 839                         if (retval) {
 840                                 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
 841                                 dev_warn(dev, "hpet_register_irq_handler "
 842                                                 " failed in rtc_init().");
 843                                 goto cleanup1;
 844                         }
 845                 } else
 846                         rtc_cmos_int_handler = cmos_interrupt;
 847
 848                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
 849                                 0, dev_name(&cmos_rtc.rtc->dev),
 850                                 cmos_rtc.rtc);
 851                 if (retval < 0) {
 852                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
 853                         goto cleanup1;
 854                 }
 855         } else {
 856                 clear_bit(RTC_FEATURE_ALARM, cmos_rtc.rtc->features);
 857         }
 858
 859         cmos_rtc.rtc->ops = &cmos_rtc_ops;
 860
 861         retval = devm_rtc_register_device(cmos_rtc.rtc);
 862         if (retval)
 863                 goto cleanup2;
 864
 865         /* Set the sync offset for the periodic 11min update correct */
 866         cmos_rtc.rtc->set_offset_nsec = NSEC_PER_SEC / 2;
 867
 868         /* export at least the first block of NVRAM */
 869         nvmem_cfg.size = address_space - NVRAM_OFFSET;
 870         devm_rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg);
 871
 872         dev_info(dev, "%s%s, %d bytes nvram%s\n",
 873                  !is_valid_irq(rtc_irq) ? "no alarms" :
 874                  cmos_rtc.mon_alrm ? "alarms up to one year" :
 875                  cmos_rtc.day_alrm ? "alarms up to one month" :
 876                  "alarms up to one day",
 877                  cmos_rtc.century ? ", y3k" : "",
 878                  nvmem_cfg.size,
 879                  use_hpet_alarm() ? ", hpet irqs" : "");
 880
 881         return 0;
 882
 883 cleanup2:
 884         if (is_valid_irq(rtc_irq))
 885                 free_irq(rtc_irq, cmos_rtc.rtc);
 886 cleanup1:
 887         cmos_rtc.dev = NULL;
 888 cleanup0:
 889         if (RTC_IOMAPPED)
 890                 release_region(ports->start, resource_size(ports));
 891         else
 892                 release_mem_region(ports->start, resource_size(ports));
 893         return retval;
 894 }
 895
 896 static void cmos_do_shutdown(int rtc_irq)
 897 {
 898         spin_lock_irq(&rtc_lock);
 899         if (is_valid_irq(rtc_irq))
 900                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
 901         spin_unlock_irq(&rtc_lock);
 902 }
 903
 904 static void cmos_do_remove(struct device *dev)
 905 {
 906         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 907         struct resource *ports;
 908
 909         cmos_do_shutdown(cmos->irq);
 910
 911         if (is_valid_irq(cmos->irq)) {
 912                 free_irq(cmos->irq, cmos->rtc);
 913                 if (use_hpet_alarm())
 914                         hpet_unregister_irq_handler(cmos_interrupt);
 915         }
 916
 917         cmos->rtc = NULL;
 918
 919         ports = cmos->iomem;
 920         if (RTC_IOMAPPED)
 921                 release_region(ports->start, resource_size(ports));
 922         else
 923                 release_mem_region(ports->start, resource_size(ports));
 924         cmos->iomem = NULL;
 925
 926         cmos->dev = NULL;
 927 }
 928
 929 static int cmos_aie_poweroff(struct device *dev)
 930 {
 931         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 932         struct rtc_time now;
 933         time64_t t_now;
 934         int retval = 0;
 935         unsigned char rtc_control;
 936
 937         if (!cmos->alarm_expires)
 938                 return -EINVAL;
 939
 940         spin_lock_irq(&rtc_lock);
 941         rtc_control = CMOS_READ(RTC_CONTROL);
 942         spin_unlock_irq(&rtc_lock);
 943
 944         /* We only care about the situation where AIE is disabled. */
 945         if (rtc_control & RTC_AIE)
 946                 return -EBUSY;
 947
 948         cmos_read_time(dev, &now);
 949         t_now = rtc_tm_to_time64(&now);
 950
 951         /*
 952          * When enabling "RTC wake-up" in BIOS setup, the machine reboots
 953          * automatically right after shutdown on some buggy boxes.
 954          * This automatic rebooting issue won't happen when the alarm
 955          * time is larger than now+1 seconds.
 956          *
 957          * If the alarm time is equal to now+1 seconds, the issue can be
 958          * prevented by cancelling the alarm.
 959          */
 960         if (cmos->alarm_expires == t_now + 1) {
 961                 struct rtc_wkalrm alarm;
 962
 963                 /* Cancel the AIE timer by configuring the past time. */
 964                 rtc_time64_to_tm(t_now - 1, &alarm.time);
 965                 alarm.enabled = 0;
 966                 retval = cmos_set_alarm(dev, &alarm);
 967         } else if (cmos->alarm_expires > t_now + 1) {
 968                 retval = -EBUSY;
 969         }
 970
 971         return retval;
 972 }
 973
 974 static int cmos_suspend(struct device *dev)
 975 {
 976         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 977         unsigned char   tmp;
 978
 979         /* only the alarm might be a wakeup event source */
 980         spin_lock_irq(&rtc_lock);
 981         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
 982         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 983                 unsigned char   mask;
 984
 985                 if (device_may_wakeup(dev))
 986                         mask = RTC_IRQMASK & ~RTC_AIE;
 987                 else
 988                         mask = RTC_IRQMASK;
 989                 tmp &= ~mask;
 990                 CMOS_WRITE(tmp, RTC_CONTROL);
 991                 if (use_hpet_alarm())
 992                         hpet_mask_rtc_irq_bit(mask);
 993                 cmos_checkintr(cmos, tmp);
 994         }
 995         spin_unlock_irq(&rtc_lock);
 996
 997         if ((tmp & RTC_AIE) && !cmos_use_acpi_alarm()) {
 998                 cmos->enabled_wake = 1;
 999                 if (cmos->wake_on)
1000                         cmos->wake_on(dev);
1001                 else
1002                         enable_irq_wake(cmos->irq);
1003         }
1004
1005         memset(&cmos->saved_wkalrm, 0, sizeof(struct rtc_wkalrm));
1006         cmos_read_alarm(dev, &cmos->saved_wkalrm);
1007
1008         dev_dbg(dev, "suspend%s, ctrl %02x\n",
1009                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
1010                         tmp);
1011
1012         return 0;
1013 }
1014
1015 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
1016  * after a detour through G3 "mechanical off", although the ACPI spec
1017  * says wakeup should only work from G1/S4 "hibernate".  To most users,
1018  * distinctions between S4 and S5 are pointless.  So when the hardware
1019  * allows, don't draw that distinction.
1020  */
1021 static inline int cmos_poweroff(struct device *dev)
1022 {
1023         if (!IS_ENABLED(CONFIG_PM))
1024                 return -ENOSYS;
1025
1026         return cmos_suspend(dev);
1027 }
1028
1029 static void cmos_check_wkalrm(struct device *dev)
1030 {
1031         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1032         struct rtc_wkalrm current_alarm;
1033         time64_t t_now;
1034         time64_t t_current_expires;
1035         time64_t t_saved_expires;
1036         struct rtc_time now;
1037
1038         /* Check if we have RTC Alarm armed */
1039         if (!(cmos->suspend_ctrl & RTC_AIE))
1040                 return;
1041
1042         cmos_read_time(dev, &now);
1043         t_now = rtc_tm_to_time64(&now);
1044
1045         /*
1046          * ACPI RTC wake event is cleared after resume from STR,
1047          * ACK the rtc irq here
1048          */
1049         if (t_now >= cmos->alarm_expires && cmos_use_acpi_alarm()) {
1050                 cmos_interrupt(0, (void *)cmos->rtc);
1051                 return;
1052         }
1053
1054         memset(&current_alarm, 0, sizeof(struct rtc_wkalrm));
1055         cmos_read_alarm(dev, &current_alarm);
1056         t_current_expires = rtc_tm_to_time64(&current_alarm.time);
1057         t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
1058         if (t_current_expires != t_saved_expires ||
1059             cmos->saved_wkalrm.enabled != current_alarm.enabled) {
1060                 cmos_set_alarm(dev, &cmos->saved_wkalrm);
1061         }
1062 }
1063
1064 static void cmos_check_acpi_rtc_status(struct device *dev,
1065                                        unsigned char *rtc_control);
1066
1067 static int __maybe_unused cmos_resume(struct device *dev)
1068 {
1069         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1070         unsigned char tmp;
1071
1072         if (cmos->enabled_wake && !cmos_use_acpi_alarm()) {
1073                 if (cmos->wake_off)
1074                         cmos->wake_off(dev);
1075                 else
1076                         disable_irq_wake(cmos->irq);
1077                 cmos->enabled_wake = 0;
1078         }
1079
1080         /* The BIOS might have changed the alarm, restore it */
1081         cmos_check_wkalrm(dev);
1082
1083         spin_lock_irq(&rtc_lock);
1084         tmp = cmos->suspend_ctrl;
1085         cmos->suspend_ctrl = 0;
1086         /* re-enable any irqs previously active */
1087         if (tmp & RTC_IRQMASK) {
1088                 unsigned char   mask;
1089
1090                 if (device_may_wakeup(dev) && use_hpet_alarm())
1091                         hpet_rtc_timer_init();
1092
1093                 do {
1094                         CMOS_WRITE(tmp, RTC_CONTROL);
1095                         if (use_hpet_alarm())
1096                                 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1097
1098                         mask = CMOS_READ(RTC_INTR_FLAGS);
1099                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1100                         if (!use_hpet_alarm() || !is_intr(mask))
1101                                 break;
1102
1103                         /* force one-shot behavior if HPET blocked
1104                          * the wake alarm's irq
1105                          */
1106                         rtc_update_irq(cmos->rtc, 1, mask);
1107                         tmp &= ~RTC_AIE;
1108                         hpet_mask_rtc_irq_bit(RTC_AIE);
1109                 } while (mask & RTC_AIE);
1110
1111                 if (tmp & RTC_AIE)
1112                         cmos_check_acpi_rtc_status(dev, &tmp);
1113         }
1114         spin_unlock_irq(&rtc_lock);
1115
1116         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1117
1118         return 0;
1119 }
1120
1121 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1122
1123 /*----------------------------------------------------------------*/
1124
1125 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1126  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1127  * probably list them in similar PNPBIOS tables; so PNP is more common.
1128  *
1129  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1130  * predate even PNPBIOS should set up platform_bus devices.
1131  */
1132
1133 #ifdef  CONFIG_ACPI
1134
1135 #include <linux/acpi.h>
1136
1137 static u32 rtc_handler(void *context)
1138 {
1139         struct device *dev = context;
1140         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1141         unsigned char rtc_control = 0;
1142         unsigned char rtc_intr;
1143         unsigned long flags;
1144
1145
1146         /*
1147          * Always update rtc irq when ACPI is used as RTC Alarm.
1148          * Or else, ACPI SCI is enabled during suspend/resume only,
1149          * update rtc irq in that case.
1150          */
1151         if (cmos_use_acpi_alarm())
1152                 cmos_interrupt(0, (void *)cmos->rtc);
1153         else {
1154                 /* Fix me: can we use cmos_interrupt() here as well? */
1155                 spin_lock_irqsave(&rtc_lock, flags);
1156                 if (cmos_rtc.suspend_ctrl)
1157                         rtc_control = CMOS_READ(RTC_CONTROL);
1158                 if (rtc_control & RTC_AIE) {
1159                         cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1160                         CMOS_WRITE(rtc_control, RTC_CONTROL);
1161                         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1162                         rtc_update_irq(cmos->rtc, 1, rtc_intr);
1163                 }
1164                 spin_unlock_irqrestore(&rtc_lock, flags);
1165         }
1166
1167         pm_wakeup_hard_event(dev);
1168         acpi_clear_event(ACPI_EVENT_RTC);
1169         acpi_disable_event(ACPI_EVENT_RTC, 0);
1170         return ACPI_INTERRUPT_HANDLED;
1171 }
1172
1173 static inline void rtc_wake_setup(struct device *dev)
1174 {
1175         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1176         /*
1177          * After the RTC handler is installed, the Fixed_RTC event should
1178          * be disabled. Only when the RTC alarm is set will it be enabled.
1179          */
1180         acpi_clear_event(ACPI_EVENT_RTC);
1181         acpi_disable_event(ACPI_EVENT_RTC, 0);
1182 }
1183
1184 static void rtc_wake_on(struct device *dev)
1185 {
1186         acpi_clear_event(ACPI_EVENT_RTC);
1187         acpi_enable_event(ACPI_EVENT_RTC, 0);
1188 }
1189
1190 static void rtc_wake_off(struct device *dev)
1191 {
1192         acpi_disable_event(ACPI_EVENT_RTC, 0);
1193 }
1194
1195 #ifdef CONFIG_X86
1196 /* Enable use_acpi_alarm mode for Intel platforms no earlier than 2015 */
1197 static void use_acpi_alarm_quirks(void)
1198 {
1199         if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
1200                 return;
1201
1202         if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
1203                 return;
1204
1205         if (!is_hpet_enabled())
1206                 return;
1207
1208         if (dmi_get_bios_year() < 2015)
1209                 return;
1210
1211         use_acpi_alarm = true;
1212 }
1213 #else
1214 static inline void use_acpi_alarm_quirks(void) { }
1215 #endif
1216
1217 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1218  * its device node and pass extra config data.  This helps its driver use
1219  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1220  * that this board's RTC is wakeup-capable (per ACPI spec).
1221  */
1222 static struct cmos_rtc_board_info acpi_rtc_info;
1223
1224 static void cmos_wake_setup(struct device *dev)
1225 {
1226         if (acpi_disabled)
1227                 return;
1228
1229         use_acpi_alarm_quirks();
1230
1231         rtc_wake_setup(dev);
1232         acpi_rtc_info.wake_on = rtc_wake_on;
1233         acpi_rtc_info.wake_off = rtc_wake_off;
1234
1235         /* workaround bug in some ACPI tables */
1236         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1237                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1238                         acpi_gbl_FADT.month_alarm);
1239                 acpi_gbl_FADT.month_alarm = 0;
1240         }
1241
1242         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1243         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1244         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1245
1246         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1247         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1248                 dev_info(dev, "RTC can wake from S4\n");
1249
1250         dev->platform_data = &acpi_rtc_info;
1251
1252         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1253         device_init_wakeup(dev, 1);
1254 }
1255
1256 static void cmos_check_acpi_rtc_status(struct device *dev,
1257                                        unsigned char *rtc_control)
1258 {
1259         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1260         acpi_event_status rtc_status;
1261         acpi_status status;
1262
1263         if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1264                 return;
1265
1266         status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1267         if (ACPI_FAILURE(status)) {
1268                 dev_err(dev, "Could not get RTC status\n");
1269         } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1270                 unsigned char mask;
1271                 *rtc_control &= ~RTC_AIE;
1272                 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1273                 mask = CMOS_READ(RTC_INTR_FLAGS);
1274                 rtc_update_irq(cmos->rtc, 1, mask);
1275         }
1276 }
1277
1278 #else
1279
1280 static void cmos_wake_setup(struct device *dev)
1281 {
1282 }
1283
1284 static void cmos_check_acpi_rtc_status(struct device *dev,
1285                                        unsigned char *rtc_control)
1286 {
1287 }
1288
1289 #endif
1290
1291 #ifdef  CONFIG_PNP
1292
1293 #include <linux/pnp.h>
1294
1295 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1296 {
1297         cmos_wake_setup(&pnp->dev);
1298
1299         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1300                 unsigned int irq = 0;
1301 #ifdef CONFIG_X86
1302                 /* Some machines contain a PNP entry for the RTC, but
1303                  * don't define the IRQ. It should always be safe to
1304                  * hardcode it on systems with a legacy PIC.
1305                  */
1306                 if (nr_legacy_irqs())
1307                         irq = RTC_IRQ;
1308 #endif
1309                 return cmos_do_probe(&pnp->dev,
1310                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1311         } else {
1312                 return cmos_do_probe(&pnp->dev,
1313                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1314                                 pnp_irq(pnp, 0));
1315         }
1316 }
1317
1318 static void cmos_pnp_remove(struct pnp_dev *pnp)
1319 {
1320         cmos_do_remove(&pnp->dev);
1321 }
1322
1323 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1324 {
1325         struct device *dev = &pnp->dev;
1326         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1327
1328         if (system_state == SYSTEM_POWER_OFF) {
1329                 int retval = cmos_poweroff(dev);
1330
1331                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1332                         return;
1333         }
1334
1335         cmos_do_shutdown(cmos->irq);
1336 }
1337
1338 static const struct pnp_device_id rtc_ids[] = {
1339         { .id = "PNP0b00", },
1340         { .id = "PNP0b01", },
1341         { .id = "PNP0b02", },
1342         { },
1343 };
1344 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1345
1346 static struct pnp_driver cmos_pnp_driver = {
1347         .name           = driver_name,
1348         .id_table       = rtc_ids,
1349         .probe          = cmos_pnp_probe,
1350         .remove         = cmos_pnp_remove,
1351         .shutdown       = cmos_pnp_shutdown,
1352
1353         /* flag ensures resume() gets called, and stops syslog spam */
1354         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1355         .driver         = {
1356                         .pm = &cmos_pm_ops,
1357         },
1358 };
1359
1360 #endif  /* CONFIG_PNP */
1361
1362 #ifdef CONFIG_OF
1363 static const struct of_device_id of_cmos_match[] = {
1364         {
1365                 .compatible = "motorola,mc146818",
1366         },
1367         { },
1368 };
1369 MODULE_DEVICE_TABLE(of, of_cmos_match);
1370
1371 static __init void cmos_of_init(struct platform_device *pdev)
1372 {
1373         struct device_node *node = pdev->dev.of_node;
1374         const __be32 *val;
1375
1376         if (!node)
1377                 return;
1378
1379         val = of_get_property(node, "ctrl-reg", NULL);
1380         if (val)
1381                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1382
1383         val = of_get_property(node, "freq-reg", NULL);
1384         if (val)
1385                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1386 }
1387 #else
1388 static inline void cmos_of_init(struct platform_device *pdev) {}
1389 #endif
1390 /*----------------------------------------------------------------*/
1391
1392 /* Platform setup should have set up an RTC device, when PNP is
1393  * unavailable ... this could happen even on (older) PCs.
1394  */
1395
1396 static int __init cmos_platform_probe(struct platform_device *pdev)
1397 {
1398         struct resource *resource;
1399         int irq;
1400
1401         cmos_of_init(pdev);
1402         cmos_wake_setup(&pdev->dev);
1403
1404         if (RTC_IOMAPPED)
1405                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1406         else
1407                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1408         irq = platform_get_irq(pdev, 0);
1409         if (irq < 0)
1410                 irq = -1;
1411
1412         return cmos_do_probe(&pdev->dev, resource, irq);
1413 }
1414
1415 static int cmos_platform_remove(struct platform_device *pdev)
1416 {
1417         cmos_do_remove(&pdev->dev);
1418         return 0;
1419 }
1420
1421 static void cmos_platform_shutdown(struct platform_device *pdev)
1422 {
1423         struct device *dev = &pdev->dev;
1424         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1425
1426         if (system_state == SYSTEM_POWER_OFF) {
1427                 int retval = cmos_poweroff(dev);
1428
1429                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1430                         return;
1431         }
1432
1433         cmos_do_shutdown(cmos->irq);
1434 }
1435
1436 /* work with hotplug and coldplug */
1437 MODULE_ALIAS("platform:rtc_cmos");
1438
1439 static struct platform_driver cmos_platform_driver = {
1440         .remove         = cmos_platform_remove,
1441         .shutdown       = cmos_platform_shutdown,
1442         .driver = {
1443                 .name           = driver_name,
1444                 .pm             = &cmos_pm_ops,
1445                 .of_match_table = of_match_ptr(of_cmos_match),
1446         }
1447 };
1448
1449 #ifdef CONFIG_PNP
1450 static bool pnp_driver_registered;
1451 #endif
1452 static bool platform_driver_registered;
1453
1454 static int __init cmos_init(void)
1455 {
1456         int retval = 0;
1457
1458 #ifdef  CONFIG_PNP
1459         retval = pnp_register_driver(&cmos_pnp_driver);
1460         if (retval == 0)
1461                 pnp_driver_registered = true;
1462 #endif
1463
1464         if (!cmos_rtc.dev) {
1465                 retval = platform_driver_probe(&cmos_platform_driver,
1466                                                cmos_platform_probe);
1467                 if (retval == 0)
1468                         platform_driver_registered = true;
1469         }
1470
1471         if (retval == 0)
1472                 return 0;
1473
1474 #ifdef  CONFIG_PNP
1475         if (pnp_driver_registered)
1476                 pnp_unregister_driver(&cmos_pnp_driver);
1477 #endif
1478         return retval;
1479 }
1480 module_init(cmos_init);
1481
1482 static void __exit cmos_exit(void)
1483 {
1484 #ifdef  CONFIG_PNP
1485         if (pnp_driver_registered)
1486                 pnp_unregister_driver(&cmos_pnp_driver);
1487 #endif
1488         if (platform_driver_registered)
1489                 platform_driver_unregister(&cmos_platform_driver);
1490 }
1491 module_exit(cmos_exit);
1492
1493
1494 MODULE_AUTHOR("David Brownell");
1495 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1496 MODULE_LICENSE("GPL");