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         int ret;
 226
 227         /*
 228          * If pm_trace abused the RTC for storage, set the timespec to 0,
 229          * which tells the caller that this RTC value is unusable.
 230          */
 231         if (!pm_trace_rtc_valid())
 232                 return -EIO;
 233
 234         ret = mc146818_get_time(t);
 235         if (ret < 0) {
 236                 dev_err_ratelimited(dev, "unable to read current time\n");
 237                 return ret;
 238         }
 239
 240         return 0;
 241 }
 242
 243 static int cmos_set_time(struct device *dev, struct rtc_time *t)
 244 {
 245         /* NOTE: this ignores the issue whereby updating the seconds
 246          * takes effect exactly 500ms after we write the register.
 247          * (Also queueing and other delays before we get this far.)
 248          */
 249         return mc146818_set_time(t);
 250 }
 251
 252 struct cmos_read_alarm_callback_param {
 253         struct cmos_rtc *cmos;
 254         struct rtc_time *time;
 255         unsigned char   rtc_control;
 256 };
 257
 258 static void cmos_read_alarm_callback(unsigned char __always_unused seconds,
 259                                      void *param_in)
 260 {
 261         struct cmos_read_alarm_callback_param *p =
 262                 (struct cmos_read_alarm_callback_param *)param_in;
 263         struct rtc_time *time = p->time;
 264
 265         time->tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
 266         time->tm_min = CMOS_READ(RTC_MINUTES_ALARM);
 267         time->tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 268
 269         if (p->cmos->day_alrm) {
 270                 /* ignore upper bits on readback per ACPI spec */
 271                 time->tm_mday = CMOS_READ(p->cmos->day_alrm) & 0x3f;
 272                 if (!time->tm_mday)
 273                         time->tm_mday = -1;
 274
 275                 if (p->cmos->mon_alrm) {
 276                         time->tm_mon = CMOS_READ(p->cmos->mon_alrm);
 277                         if (!time->tm_mon)
 278                                 time->tm_mon = -1;
 279                 }
 280         }
 281
 282         p->rtc_control = CMOS_READ(RTC_CONTROL);
 283 }
 284
 285 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 286 {
 287         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 288         struct cmos_read_alarm_callback_param p = {
 289                 .cmos = cmos,
 290                 .time = &t->time,
 291         };
 292
 293         /* This not only a rtc_op, but also called directly */
 294         if (!is_valid_irq(cmos->irq))
 295                 return -EIO;
 296
 297         /* Basic alarms only support hour, minute, and seconds fields.
 298          * Some also support day and month, for alarms up to a year in
 299          * the future.
 300          */
 301
 302         /* Some Intel chipsets disconnect the alarm registers when the clock
 303          * update is in progress - during this time reads return bogus values
 304          * and writes may fail silently. See for example "7th Generation Intel®
 305          * Processor Family I/O for U/Y Platforms [...] Datasheet", section
 306          * 27.7.1
 307          *
 308          * Use the mc146818_avoid_UIP() function to avoid this.
 309          */
 310         if (!mc146818_avoid_UIP(cmos_read_alarm_callback, &p))
 311                 return -EIO;
 312
 313         if (!(p.rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 314                 if (((unsigned)t->time.tm_sec) < 0x60)
 315                         t->time.tm_sec = bcd2bin(t->time.tm_sec);
 316                 else
 317                         t->time.tm_sec = -1;
 318                 if (((unsigned)t->time.tm_min) < 0x60)
 319                         t->time.tm_min = bcd2bin(t->time.tm_min);
 320                 else
 321                         t->time.tm_min = -1;
 322                 if (((unsigned)t->time.tm_hour) < 0x24)
 323                         t->time.tm_hour = bcd2bin(t->time.tm_hour);
 324                 else
 325                         t->time.tm_hour = -1;
 326
 327                 if (cmos->day_alrm) {
 328                         if (((unsigned)t->time.tm_mday) <= 0x31)
 329                                 t->time.tm_mday = bcd2bin(t->time.tm_mday);
 330                         else
 331                                 t->time.tm_mday = -1;
 332
 333                         if (cmos->mon_alrm) {
 334                                 if (((unsigned)t->time.tm_mon) <= 0x12)
 335                                         t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
 336                                 else
 337                                         t->time.tm_mon = -1;
 338                         }
 339                 }
 340         }
 341
 342         t->enabled = !!(p.rtc_control & RTC_AIE);
 343         t->pending = 0;
 344
 345         return 0;
 346 }
 347
 348 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
 349 {
 350         unsigned char   rtc_intr;
 351
 352         /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
 353          * allegedly some older rtcs need that to handle irqs properly
 354          */
 355         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 356
 357         if (use_hpet_alarm())
 358                 return;
 359
 360         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 361         if (is_intr(rtc_intr))
 362                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
 363 }
 364
 365 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
 366 {
 367         unsigned char   rtc_control;
 368
 369         /* flush any pending IRQ status, notably for update irqs,
 370          * before we enable new IRQs
 371          */
 372         rtc_control = CMOS_READ(RTC_CONTROL);
 373         cmos_checkintr(cmos, rtc_control);
 374
 375         rtc_control |= mask;
 376         CMOS_WRITE(rtc_control, RTC_CONTROL);
 377         if (use_hpet_alarm())
 378                 hpet_set_rtc_irq_bit(mask);
 379
 380         if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
 381                 if (cmos->wake_on)
 382                         cmos->wake_on(cmos->dev);
 383         }
 384
 385         cmos_checkintr(cmos, rtc_control);
 386 }
 387
 388 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
 389 {
 390         unsigned char   rtc_control;
 391
 392         rtc_control = CMOS_READ(RTC_CONTROL);
 393         rtc_control &= ~mask;
 394         CMOS_WRITE(rtc_control, RTC_CONTROL);
 395         if (use_hpet_alarm())
 396                 hpet_mask_rtc_irq_bit(mask);
 397
 398         if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
 399                 if (cmos->wake_off)
 400                         cmos->wake_off(cmos->dev);
 401         }
 402
 403         cmos_checkintr(cmos, rtc_control);
 404 }
 405
 406 static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t)
 407 {
 408         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 409         struct rtc_time now;
 410
 411         cmos_read_time(dev, &now);
 412
 413         if (!cmos->day_alrm) {
 414                 time64_t t_max_date;
 415                 time64_t t_alrm;
 416
 417                 t_max_date = rtc_tm_to_time64(&now);
 418                 t_max_date += 24 * 60 * 60 - 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 day in the future\n");
 423                         return -EINVAL;
 424                 }
 425         } else if (!cmos->mon_alrm) {
 426                 struct rtc_time max_date = now;
 427                 time64_t t_max_date;
 428                 time64_t t_alrm;
 429                 int max_mday;
 430
 431                 if (max_date.tm_mon == 11) {
 432                         max_date.tm_mon = 0;
 433                         max_date.tm_year += 1;
 434                 } else {
 435                         max_date.tm_mon += 1;
 436                 }
 437                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 438                 if (max_date.tm_mday > max_mday)
 439                         max_date.tm_mday = max_mday;
 440
 441                 t_max_date = rtc_tm_to_time64(&max_date);
 442                 t_max_date -= 1;
 443                 t_alrm = rtc_tm_to_time64(&t->time);
 444                 if (t_alrm > t_max_date) {
 445                         dev_err(dev,
 446                                 "Alarms can be up to one month in the future\n");
 447                         return -EINVAL;
 448                 }
 449         } else {
 450                 struct rtc_time max_date = now;
 451                 time64_t t_max_date;
 452                 time64_t t_alrm;
 453                 int max_mday;
 454
 455                 max_date.tm_year += 1;
 456                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 457                 if (max_date.tm_mday > max_mday)
 458                         max_date.tm_mday = max_mday;
 459
 460                 t_max_date = rtc_tm_to_time64(&max_date);
 461                 t_max_date -= 1;
 462                 t_alrm = rtc_tm_to_time64(&t->time);
 463                 if (t_alrm > t_max_date) {
 464                         dev_err(dev,
 465                                 "Alarms can be up to one year in the future\n");
 466                         return -EINVAL;
 467                 }
 468         }
 469
 470         return 0;
 471 }
 472
 473 struct cmos_set_alarm_callback_param {
 474         struct cmos_rtc *cmos;
 475         unsigned char mon, mday, hrs, min, sec;
 476         struct rtc_wkalrm *t;
 477 };
 478
 479 /* Note: this function may be executed by mc146818_avoid_UIP() more then
 480  *       once
 481  */
 482 static void cmos_set_alarm_callback(unsigned char __always_unused seconds,
 483                                     void *param_in)
 484 {
 485         struct cmos_set_alarm_callback_param *p =
 486                 (struct cmos_set_alarm_callback_param *)param_in;
 487
 488         /* next rtc irq must not be from previous alarm setting */
 489         cmos_irq_disable(p->cmos, RTC_AIE);
 490
 491         /* update alarm */
 492         CMOS_WRITE(p->hrs, RTC_HOURS_ALARM);
 493         CMOS_WRITE(p->min, RTC_MINUTES_ALARM);
 494         CMOS_WRITE(p->sec, RTC_SECONDS_ALARM);
 495
 496         /* the system may support an "enhanced" alarm */
 497         if (p->cmos->day_alrm) {
 498                 CMOS_WRITE(p->mday, p->cmos->day_alrm);
 499                 if (p->cmos->mon_alrm)
 500                         CMOS_WRITE(p->mon, p->cmos->mon_alrm);
 501         }
 502
 503         if (use_hpet_alarm()) {
 504                 /*
 505                  * FIXME the HPET alarm glue currently ignores day_alrm
 506                  * and mon_alrm ...
 507                  */
 508                 hpet_set_alarm_time(p->t->time.tm_hour, p->t->time.tm_min,
 509                                     p->t->time.tm_sec);
 510         }
 511
 512         if (p->t->enabled)
 513                 cmos_irq_enable(p->cmos, RTC_AIE);
 514 }
 515
 516 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 517 {
 518         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 519         struct cmos_set_alarm_callback_param p = {
 520                 .cmos = cmos,
 521                 .t = t
 522         };
 523         unsigned char rtc_control;
 524         int ret;
 525
 526         /* This not only a rtc_op, but also called directly */
 527         if (!is_valid_irq(cmos->irq))
 528                 return -EIO;
 529
 530         ret = cmos_validate_alarm(dev, t);
 531         if (ret < 0)
 532                 return ret;
 533
 534         p.mon = t->time.tm_mon + 1;
 535         p.mday = t->time.tm_mday;
 536         p.hrs = t->time.tm_hour;
 537         p.min = t->time.tm_min;
 538         p.sec = t->time.tm_sec;
 539
 540         spin_lock_irq(&rtc_lock);
 541         rtc_control = CMOS_READ(RTC_CONTROL);
 542         spin_unlock_irq(&rtc_lock);
 543
 544         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 545                 /* Writing 0xff means "don't care" or "match all".  */
 546                 p.mon = (p.mon <= 12) ? bin2bcd(p.mon) : 0xff;
 547                 p.mday = (p.mday >= 1 && p.mday <= 31) ? bin2bcd(p.mday) : 0xff;
 548                 p.hrs = (p.hrs < 24) ? bin2bcd(p.hrs) : 0xff;
 549                 p.min = (p.min < 60) ? bin2bcd(p.min) : 0xff;
 550                 p.sec = (p.sec < 60) ? bin2bcd(p.sec) : 0xff;
 551         }
 552
 553         /*
 554          * Some Intel chipsets disconnect the alarm registers when the clock
 555          * update is in progress - during this time writes fail silently.
 556          *
 557          * Use mc146818_avoid_UIP() to avoid this.
 558          */
 559         if (!mc146818_avoid_UIP(cmos_set_alarm_callback, &p))
 560                 return -EIO;
 561
 562         cmos->alarm_expires = rtc_tm_to_time64(&t->time);
 563
 564         return 0;
 565 }
 566
 567 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 568 {
 569         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 570         unsigned long   flags;
 571
 572         spin_lock_irqsave(&rtc_lock, flags);
 573
 574         if (enabled)
 575                 cmos_irq_enable(cmos, RTC_AIE);
 576         else
 577                 cmos_irq_disable(cmos, RTC_AIE);
 578
 579         spin_unlock_irqrestore(&rtc_lock, flags);
 580         return 0;
 581 }
 582
 583 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 584
 585 static int cmos_procfs(struct device *dev, struct seq_file *seq)
 586 {
 587         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 588         unsigned char   rtc_control, valid;
 589
 590         spin_lock_irq(&rtc_lock);
 591         rtc_control = CMOS_READ(RTC_CONTROL);
 592         valid = CMOS_READ(RTC_VALID);
 593         spin_unlock_irq(&rtc_lock);
 594
 595         /* NOTE:  at least ICH6 reports battery status using a different
 596          * (non-RTC) bit; and SQWE is ignored on many current systems.
 597          */
 598         seq_printf(seq,
 599                    "periodic_IRQ\t: %s\n"
 600                    "update_IRQ\t: %s\n"
 601                    "HPET_emulated\t: %s\n"
 602                    // "square_wave\t: %s\n"
 603                    "BCD\t\t: %s\n"
 604                    "DST_enable\t: %s\n"
 605                    "periodic_freq\t: %d\n"
 606                    "batt_status\t: %s\n",
 607                    (rtc_control & RTC_PIE) ? "yes" : "no",
 608                    (rtc_control & RTC_UIE) ? "yes" : "no",
 609                    use_hpet_alarm() ? "yes" : "no",
 610                    // (rtc_control & RTC_SQWE) ? "yes" : "no",
 611                    (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 612                    (rtc_control & RTC_DST_EN) ? "yes" : "no",
 613                    cmos->rtc->irq_freq,
 614                    (valid & RTC_VRT) ? "okay" : "dead");
 615
 616         return 0;
 617 }
 618
 619 #else
 620 #define cmos_procfs     NULL
 621 #endif
 622
 623 static const struct rtc_class_ops cmos_rtc_ops = {
 624         .read_time              = cmos_read_time,
 625         .set_time               = cmos_set_time,
 626         .read_alarm             = cmos_read_alarm,
 627         .set_alarm              = cmos_set_alarm,
 628         .proc                   = cmos_procfs,
 629         .alarm_irq_enable       = cmos_alarm_irq_enable,
 630 };
 631
 632 /*----------------------------------------------------------------*/
 633
 634 /*
 635  * All these chips have at least 64 bytes of address space, shared by
 636  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 637  * by boot firmware.  Modern chips have 128 or 256 bytes.
 638  */
 639
 640 #define NVRAM_OFFSET    (RTC_REG_D + 1)
 641
 642 static int cmos_nvram_read(void *priv, unsigned int off, void *val,
 643                            size_t count)
 644 {
 645         unsigned char *buf = val;
 646         int     retval;
 647
 648         off += NVRAM_OFFSET;
 649         spin_lock_irq(&rtc_lock);
 650         for (retval = 0; count; count--, off++, retval++) {
 651                 if (off < 128)
 652                         *buf++ = CMOS_READ(off);
 653                 else if (can_bank2)
 654                         *buf++ = cmos_read_bank2(off);
 655                 else
 656                         break;
 657         }
 658         spin_unlock_irq(&rtc_lock);
 659
 660         return retval;
 661 }
 662
 663 static int cmos_nvram_write(void *priv, unsigned int off, void *val,
 664                             size_t count)
 665 {
 666         struct cmos_rtc *cmos = priv;
 667         unsigned char   *buf = val;
 668         int             retval;
 669
 670         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 671          * checksum on part of the NVRAM data.  That's currently ignored
 672          * here.  If userspace is smart enough to know what fields of
 673          * NVRAM to update, updating checksums is also part of its job.
 674          */
 675         off += NVRAM_OFFSET;
 676         spin_lock_irq(&rtc_lock);
 677         for (retval = 0; count; count--, off++, retval++) {
 678                 /* don't trash RTC registers */
 679                 if (off == cmos->day_alrm
 680                                 || off == cmos->mon_alrm
 681                                 || off == cmos->century)
 682                         buf++;
 683                 else if (off < 128)
 684                         CMOS_WRITE(*buf++, off);
 685                 else if (can_bank2)
 686                         cmos_write_bank2(*buf++, off);
 687                 else
 688                         break;
 689         }
 690         spin_unlock_irq(&rtc_lock);
 691
 692         return retval;
 693 }
 694
 695 /*----------------------------------------------------------------*/
 696
 697 static struct cmos_rtc  cmos_rtc;
 698
 699 static irqreturn_t cmos_interrupt(int irq, void *p)
 700 {
 701         u8              irqstat;
 702         u8              rtc_control;
 703
 704         spin_lock(&rtc_lock);
 705
 706         /* When the HPET interrupt handler calls us, the interrupt
 707          * status is passed as arg1 instead of the irq number.  But
 708          * always clear irq status, even when HPET is in the way.
 709          *
 710          * Note that HPET and RTC are almost certainly out of phase,
 711          * giving different IRQ status ...
 712          */
 713         irqstat = CMOS_READ(RTC_INTR_FLAGS);
 714         rtc_control = CMOS_READ(RTC_CONTROL);
 715         if (use_hpet_alarm())
 716                 irqstat = (unsigned long)irq & 0xF0;
 717
 718         /* If we were suspended, RTC_CONTROL may not be accurate since the
 719          * bios may have cleared it.
 720          */
 721         if (!cmos_rtc.suspend_ctrl)
 722                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 723         else
 724                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 725
 726         /* All Linux RTC alarms should be treated as if they were oneshot.
 727          * Similar code may be needed in system wakeup paths, in case the
 728          * alarm woke the system.
 729          */
 730         if (irqstat & RTC_AIE) {
 731                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 732                 rtc_control &= ~RTC_AIE;
 733                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 734                 if (use_hpet_alarm())
 735                         hpet_mask_rtc_irq_bit(RTC_AIE);
 736                 CMOS_READ(RTC_INTR_FLAGS);
 737         }
 738         spin_unlock(&rtc_lock);
 739
 740         if (is_intr(irqstat)) {
 741                 rtc_update_irq(p, 1, irqstat);
 742                 return IRQ_HANDLED;
 743         } else
 744                 return IRQ_NONE;
 745 }
 746
 747 #ifdef  CONFIG_PNP
 748 #define INITSECTION
 749
 750 #else
 751 #define INITSECTION     __init
 752 #endif
 753
 754 static int INITSECTION
 755 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 756 {
 757         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
 758         int                             retval = 0;
 759         unsigned char                   rtc_control;
 760         unsigned                        address_space;
 761         u32                             flags = 0;
 762         struct nvmem_config nvmem_cfg = {
 763                 .name = "cmos_nvram",
 764                 .word_size = 1,
 765                 .stride = 1,
 766                 .reg_read = cmos_nvram_read,
 767                 .reg_write = cmos_nvram_write,
 768                 .priv = &cmos_rtc,
 769         };
 770
 771         /* there can be only one ... */
 772         if (cmos_rtc.dev)
 773                 return -EBUSY;
 774
 775         if (!ports)
 776                 return -ENODEV;
 777
 778         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 779          *
 780          * REVISIT non-x86 systems may instead use memory space resources
 781          * (needing ioremap etc), not i/o space resources like this ...
 782          */
 783         if (RTC_IOMAPPED)
 784                 ports = request_region(ports->start, resource_size(ports),
 785                                        driver_name);
 786         else
 787                 ports = request_mem_region(ports->start, resource_size(ports),
 788                                            driver_name);
 789         if (!ports) {
 790                 dev_dbg(dev, "i/o registers already in use\n");
 791                 return -EBUSY;
 792         }
 793
 794         cmos_rtc.irq = rtc_irq;
 795         cmos_rtc.iomem = ports;
 796
 797         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 798          * driver did, but don't reject unknown configs.   Old hardware
 799          * won't address 128 bytes.  Newer chips have multiple banks,
 800          * though they may not be listed in one I/O resource.
 801          */
 802 #if     defined(CONFIG_ATARI)
 803         address_space = 64;
 804 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 805                         || defined(__sparc__) || defined(__mips__) \
 806                         || defined(__powerpc__)
 807         address_space = 128;
 808 #else
 809 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 810         address_space = 128;
 811 #endif
 812         if (can_bank2 && ports->end > (ports->start + 1))
 813                 address_space = 256;
 814
 815         /* For ACPI systems extension info comes from the FADT.  On others,
 816          * board specific setup provides it as appropriate.  Systems where
 817          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 818          * some almost-clones) can provide hooks to make that behave.
 819          *
 820          * Note that ACPI doesn't preclude putting these registers into
 821          * "extended" areas of the chip, including some that we won't yet
 822          * expect CMOS_READ and friends to handle.
 823          */
 824         if (info) {
 825                 if (info->flags)
 826                         flags = info->flags;
 827                 if (info->address_space)
 828                         address_space = info->address_space;
 829
 830                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
 831                         cmos_rtc.day_alrm = info->rtc_day_alarm;
 832                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
 833                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
 834                 if (info->rtc_century && info->rtc_century < 128)
 835                         cmos_rtc.century = info->rtc_century;
 836
 837                 if (info->wake_on && info->wake_off) {
 838                         cmos_rtc.wake_on = info->wake_on;
 839                         cmos_rtc.wake_off = info->wake_off;
 840                 }
 841         }
 842
 843         cmos_rtc.dev = dev;
 844         dev_set_drvdata(dev, &cmos_rtc);
 845
 846         cmos_rtc.rtc = devm_rtc_allocate_device(dev);
 847         if (IS_ERR(cmos_rtc.rtc)) {
 848                 retval = PTR_ERR(cmos_rtc.rtc);
 849                 goto cleanup0;
 850         }
 851
 852         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 853
 854         if (!mc146818_does_rtc_work()) {
 855                 dev_warn(dev, "broken or not accessible\n");
 856                 retval = -ENXIO;
 857                 goto cleanup1;
 858         }
 859
 860         spin_lock_irq(&rtc_lock);
 861
 862         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
 863                 /* force periodic irq to CMOS reset default of 1024Hz;
 864                  *
 865                  * REVISIT it's been reported that at least one x86_64 ALI
 866                  * mobo doesn't use 32KHz here ... for portability we might
 867                  * need to do something about other clock frequencies.
 868                  */
 869                 cmos_rtc.rtc->irq_freq = 1024;
 870                 if (use_hpet_alarm())
 871                         hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
 872                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
 873         }
 874
 875         /* disable irqs */
 876         if (is_valid_irq(rtc_irq))
 877                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
 878
 879         rtc_control = CMOS_READ(RTC_CONTROL);
 880
 881         spin_unlock_irq(&rtc_lock);
 882
 883         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
 884                 dev_warn(dev, "only 24-hr supported\n");
 885                 retval = -ENXIO;
 886                 goto cleanup1;
 887         }
 888
 889         if (use_hpet_alarm())
 890                 hpet_rtc_timer_init();
 891
 892         if (is_valid_irq(rtc_irq)) {
 893                 irq_handler_t rtc_cmos_int_handler;
 894
 895                 if (use_hpet_alarm()) {
 896                         rtc_cmos_int_handler = hpet_rtc_interrupt;
 897                         retval = hpet_register_irq_handler(cmos_interrupt);
 898                         if (retval) {
 899                                 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
 900                                 dev_warn(dev, "hpet_register_irq_handler "
 901                                                 " failed in rtc_init().");
 902                                 goto cleanup1;
 903                         }
 904                 } else
 905                         rtc_cmos_int_handler = cmos_interrupt;
 906
 907                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
 908                                 0, dev_name(&cmos_rtc.rtc->dev),
 909                                 cmos_rtc.rtc);
 910                 if (retval < 0) {
 911                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
 912                         goto cleanup1;
 913                 }
 914         } else {
 915                 clear_bit(RTC_FEATURE_ALARM, cmos_rtc.rtc->features);
 916         }
 917
 918         cmos_rtc.rtc->ops = &cmos_rtc_ops;
 919
 920         retval = devm_rtc_register_device(cmos_rtc.rtc);
 921         if (retval)
 922                 goto cleanup2;
 923
 924         /* Set the sync offset for the periodic 11min update correct */
 925         cmos_rtc.rtc->set_offset_nsec = NSEC_PER_SEC / 2;
 926
 927         /* export at least the first block of NVRAM */
 928         nvmem_cfg.size = address_space - NVRAM_OFFSET;
 929         devm_rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg);
 930
 931         dev_info(dev, "%s%s, %d bytes nvram%s\n",
 932                  !is_valid_irq(rtc_irq) ? "no alarms" :
 933                  cmos_rtc.mon_alrm ? "alarms up to one year" :
 934                  cmos_rtc.day_alrm ? "alarms up to one month" :
 935                  "alarms up to one day",
 936                  cmos_rtc.century ? ", y3k" : "",
 937                  nvmem_cfg.size,
 938                  use_hpet_alarm() ? ", hpet irqs" : "");
 939
 940         return 0;
 941
 942 cleanup2:
 943         if (is_valid_irq(rtc_irq))
 944                 free_irq(rtc_irq, cmos_rtc.rtc);
 945 cleanup1:
 946         cmos_rtc.dev = NULL;
 947 cleanup0:
 948         if (RTC_IOMAPPED)
 949                 release_region(ports->start, resource_size(ports));
 950         else
 951                 release_mem_region(ports->start, resource_size(ports));
 952         return retval;
 953 }
 954
 955 static void cmos_do_shutdown(int rtc_irq)
 956 {
 957         spin_lock_irq(&rtc_lock);
 958         if (is_valid_irq(rtc_irq))
 959                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
 960         spin_unlock_irq(&rtc_lock);
 961 }
 962
 963 static void cmos_do_remove(struct device *dev)
 964 {
 965         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 966         struct resource *ports;
 967
 968         cmos_do_shutdown(cmos->irq);
 969
 970         if (is_valid_irq(cmos->irq)) {
 971                 free_irq(cmos->irq, cmos->rtc);
 972                 if (use_hpet_alarm())
 973                         hpet_unregister_irq_handler(cmos_interrupt);
 974         }
 975
 976         cmos->rtc = NULL;
 977
 978         ports = cmos->iomem;
 979         if (RTC_IOMAPPED)
 980                 release_region(ports->start, resource_size(ports));
 981         else
 982                 release_mem_region(ports->start, resource_size(ports));
 983         cmos->iomem = NULL;
 984
 985         cmos->dev = NULL;
 986 }
 987
 988 static int cmos_aie_poweroff(struct device *dev)
 989 {
 990         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 991         struct rtc_time now;
 992         time64_t t_now;
 993         int retval = 0;
 994         unsigned char rtc_control;
 995
 996         if (!cmos->alarm_expires)
 997                 return -EINVAL;
 998
 999         spin_lock_irq(&rtc_lock);
1000         rtc_control = CMOS_READ(RTC_CONTROL);
1001         spin_unlock_irq(&rtc_lock);
1002
1003         /* We only care about the situation where AIE is disabled. */
1004         if (rtc_control & RTC_AIE)
1005                 return -EBUSY;
1006
1007         cmos_read_time(dev, &now);
1008         t_now = rtc_tm_to_time64(&now);
1009
1010         /*
1011          * When enabling "RTC wake-up" in BIOS setup, the machine reboots
1012          * automatically right after shutdown on some buggy boxes.
1013          * This automatic rebooting issue won't happen when the alarm
1014          * time is larger than now+1 seconds.
1015          *
1016          * If the alarm time is equal to now+1 seconds, the issue can be
1017          * prevented by cancelling the alarm.
1018          */
1019         if (cmos->alarm_expires == t_now + 1) {
1020                 struct rtc_wkalrm alarm;
1021
1022                 /* Cancel the AIE timer by configuring the past time. */
1023                 rtc_time64_to_tm(t_now - 1, &alarm.time);
1024                 alarm.enabled = 0;
1025                 retval = cmos_set_alarm(dev, &alarm);
1026         } else if (cmos->alarm_expires > t_now + 1) {
1027                 retval = -EBUSY;
1028         }
1029
1030         return retval;
1031 }
1032
1033 static int cmos_suspend(struct device *dev)
1034 {
1035         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1036         unsigned char   tmp;
1037
1038         /* only the alarm might be a wakeup event source */
1039         spin_lock_irq(&rtc_lock);
1040         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
1041         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
1042                 unsigned char   mask;
1043
1044                 if (device_may_wakeup(dev))
1045                         mask = RTC_IRQMASK & ~RTC_AIE;
1046                 else
1047                         mask = RTC_IRQMASK;
1048                 tmp &= ~mask;
1049                 CMOS_WRITE(tmp, RTC_CONTROL);
1050                 if (use_hpet_alarm())
1051                         hpet_mask_rtc_irq_bit(mask);
1052                 cmos_checkintr(cmos, tmp);
1053         }
1054         spin_unlock_irq(&rtc_lock);
1055
1056         if ((tmp & RTC_AIE) && !cmos_use_acpi_alarm()) {
1057                 cmos->enabled_wake = 1;
1058                 if (cmos->wake_on)
1059                         cmos->wake_on(dev);
1060                 else
1061                         enable_irq_wake(cmos->irq);
1062         }
1063
1064         memset(&cmos->saved_wkalrm, 0, sizeof(struct rtc_wkalrm));
1065         cmos_read_alarm(dev, &cmos->saved_wkalrm);
1066
1067         dev_dbg(dev, "suspend%s, ctrl %02x\n",
1068                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
1069                         tmp);
1070
1071         return 0;
1072 }
1073
1074 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
1075  * after a detour through G3 "mechanical off", although the ACPI spec
1076  * says wakeup should only work from G1/S4 "hibernate".  To most users,
1077  * distinctions between S4 and S5 are pointless.  So when the hardware
1078  * allows, don't draw that distinction.
1079  */
1080 static inline int cmos_poweroff(struct device *dev)
1081 {
1082         if (!IS_ENABLED(CONFIG_PM))
1083                 return -ENOSYS;
1084
1085         return cmos_suspend(dev);
1086 }
1087
1088 static void cmos_check_wkalrm(struct device *dev)
1089 {
1090         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1091         struct rtc_wkalrm current_alarm;
1092         time64_t t_now;
1093         time64_t t_current_expires;
1094         time64_t t_saved_expires;
1095         struct rtc_time now;
1096
1097         /* Check if we have RTC Alarm armed */
1098         if (!(cmos->suspend_ctrl & RTC_AIE))
1099                 return;
1100
1101         cmos_read_time(dev, &now);
1102         t_now = rtc_tm_to_time64(&now);
1103
1104         /*
1105          * ACPI RTC wake event is cleared after resume from STR,
1106          * ACK the rtc irq here
1107          */
1108         if (t_now >= cmos->alarm_expires && cmos_use_acpi_alarm()) {
1109                 local_irq_disable();
1110                 cmos_interrupt(0, (void *)cmos->rtc);
1111                 local_irq_enable();
1112                 return;
1113         }
1114
1115         memset(&current_alarm, 0, sizeof(struct rtc_wkalrm));
1116         cmos_read_alarm(dev, &current_alarm);
1117         t_current_expires = rtc_tm_to_time64(&current_alarm.time);
1118         t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
1119         if (t_current_expires != t_saved_expires ||
1120             cmos->saved_wkalrm.enabled != current_alarm.enabled) {
1121                 cmos_set_alarm(dev, &cmos->saved_wkalrm);
1122         }
1123 }
1124
1125 static void cmos_check_acpi_rtc_status(struct device *dev,
1126                                        unsigned char *rtc_control);
1127
1128 static int __maybe_unused cmos_resume(struct device *dev)
1129 {
1130         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1131         unsigned char tmp;
1132
1133         if (cmos->enabled_wake && !cmos_use_acpi_alarm()) {
1134                 if (cmos->wake_off)
1135                         cmos->wake_off(dev);
1136                 else
1137                         disable_irq_wake(cmos->irq);
1138                 cmos->enabled_wake = 0;
1139         }
1140
1141         /* The BIOS might have changed the alarm, restore it */
1142         cmos_check_wkalrm(dev);
1143
1144         spin_lock_irq(&rtc_lock);
1145         tmp = cmos->suspend_ctrl;
1146         cmos->suspend_ctrl = 0;
1147         /* re-enable any irqs previously active */
1148         if (tmp & RTC_IRQMASK) {
1149                 unsigned char   mask;
1150
1151                 if (device_may_wakeup(dev) && use_hpet_alarm())
1152                         hpet_rtc_timer_init();
1153
1154                 do {
1155                         CMOS_WRITE(tmp, RTC_CONTROL);
1156                         if (use_hpet_alarm())
1157                                 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1158
1159                         mask = CMOS_READ(RTC_INTR_FLAGS);
1160                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1161                         if (!use_hpet_alarm() || !is_intr(mask))
1162                                 break;
1163
1164                         /* force one-shot behavior if HPET blocked
1165                          * the wake alarm's irq
1166                          */
1167                         rtc_update_irq(cmos->rtc, 1, mask);
1168                         tmp &= ~RTC_AIE;
1169                         hpet_mask_rtc_irq_bit(RTC_AIE);
1170                 } while (mask & RTC_AIE);
1171
1172                 if (tmp & RTC_AIE)
1173                         cmos_check_acpi_rtc_status(dev, &tmp);
1174         }
1175         spin_unlock_irq(&rtc_lock);
1176
1177         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1178
1179         return 0;
1180 }
1181
1182 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1183
1184 /*----------------------------------------------------------------*/
1185
1186 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1187  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1188  * probably list them in similar PNPBIOS tables; so PNP is more common.
1189  *
1190  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1191  * predate even PNPBIOS should set up platform_bus devices.
1192  */
1193
1194 #ifdef  CONFIG_ACPI
1195
1196 #include <linux/acpi.h>
1197
1198 static u32 rtc_handler(void *context)
1199 {
1200         struct device *dev = context;
1201         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1202         unsigned char rtc_control = 0;
1203         unsigned char rtc_intr;
1204         unsigned long flags;
1205
1206
1207         /*
1208          * Always update rtc irq when ACPI is used as RTC Alarm.
1209          * Or else, ACPI SCI is enabled during suspend/resume only,
1210          * update rtc irq in that case.
1211          */
1212         if (cmos_use_acpi_alarm())
1213                 cmos_interrupt(0, (void *)cmos->rtc);
1214         else {
1215                 /* Fix me: can we use cmos_interrupt() here as well? */
1216                 spin_lock_irqsave(&rtc_lock, flags);
1217                 if (cmos_rtc.suspend_ctrl)
1218                         rtc_control = CMOS_READ(RTC_CONTROL);
1219                 if (rtc_control & RTC_AIE) {
1220                         cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1221                         CMOS_WRITE(rtc_control, RTC_CONTROL);
1222                         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1223                         rtc_update_irq(cmos->rtc, 1, rtc_intr);
1224                 }
1225                 spin_unlock_irqrestore(&rtc_lock, flags);
1226         }
1227
1228         pm_wakeup_hard_event(dev);
1229         acpi_clear_event(ACPI_EVENT_RTC);
1230         acpi_disable_event(ACPI_EVENT_RTC, 0);
1231         return ACPI_INTERRUPT_HANDLED;
1232 }
1233
1234 static inline void rtc_wake_setup(struct device *dev)
1235 {
1236         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1237         /*
1238          * After the RTC handler is installed, the Fixed_RTC event should
1239          * be disabled. Only when the RTC alarm is set will it be enabled.
1240          */
1241         acpi_clear_event(ACPI_EVENT_RTC);
1242         acpi_disable_event(ACPI_EVENT_RTC, 0);
1243 }
1244
1245 static void rtc_wake_on(struct device *dev)
1246 {
1247         acpi_clear_event(ACPI_EVENT_RTC);
1248         acpi_enable_event(ACPI_EVENT_RTC, 0);
1249 }
1250
1251 static void rtc_wake_off(struct device *dev)
1252 {
1253         acpi_disable_event(ACPI_EVENT_RTC, 0);
1254 }
1255
1256 #ifdef CONFIG_X86
1257 /* Enable use_acpi_alarm mode for Intel platforms no earlier than 2015 */
1258 static void use_acpi_alarm_quirks(void)
1259 {
1260         if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
1261                 return;
1262
1263         if (!is_hpet_enabled())
1264                 return;
1265
1266         if (dmi_get_bios_year() < 2015)
1267                 return;
1268
1269         use_acpi_alarm = true;
1270 }
1271 #else
1272 static inline void use_acpi_alarm_quirks(void) { }
1273 #endif
1274
1275 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1276  * its device node and pass extra config data.  This helps its driver use
1277  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1278  * that this board's RTC is wakeup-capable (per ACPI spec).
1279  */
1280 static struct cmos_rtc_board_info acpi_rtc_info;
1281
1282 static void cmos_wake_setup(struct device *dev)
1283 {
1284         if (acpi_disabled)
1285                 return;
1286
1287         use_acpi_alarm_quirks();
1288
1289         rtc_wake_setup(dev);
1290         acpi_rtc_info.wake_on = rtc_wake_on;
1291         acpi_rtc_info.wake_off = rtc_wake_off;
1292
1293         /* workaround bug in some ACPI tables */
1294         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1295                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1296                         acpi_gbl_FADT.month_alarm);
1297                 acpi_gbl_FADT.month_alarm = 0;
1298         }
1299
1300         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1301         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1302         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1303
1304         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1305         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1306                 dev_info(dev, "RTC can wake from S4\n");
1307
1308         dev->platform_data = &acpi_rtc_info;
1309
1310         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1311         device_init_wakeup(dev, 1);
1312 }
1313
1314 static void cmos_check_acpi_rtc_status(struct device *dev,
1315                                        unsigned char *rtc_control)
1316 {
1317         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1318         acpi_event_status rtc_status;
1319         acpi_status status;
1320
1321         if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1322                 return;
1323
1324         status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1325         if (ACPI_FAILURE(status)) {
1326                 dev_err(dev, "Could not get RTC status\n");
1327         } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1328                 unsigned char mask;
1329                 *rtc_control &= ~RTC_AIE;
1330                 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1331                 mask = CMOS_READ(RTC_INTR_FLAGS);
1332                 rtc_update_irq(cmos->rtc, 1, mask);
1333         }
1334 }
1335
1336 #else
1337
1338 static void cmos_wake_setup(struct device *dev)
1339 {
1340 }
1341
1342 static void cmos_check_acpi_rtc_status(struct device *dev,
1343                                        unsigned char *rtc_control)
1344 {
1345 }
1346
1347 #endif
1348
1349 #ifdef  CONFIG_PNP
1350
1351 #include <linux/pnp.h>
1352
1353 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1354 {
1355         cmos_wake_setup(&pnp->dev);
1356
1357         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1358                 unsigned int irq = 0;
1359 #ifdef CONFIG_X86
1360                 /* Some machines contain a PNP entry for the RTC, but
1361                  * don't define the IRQ. It should always be safe to
1362                  * hardcode it on systems with a legacy PIC.
1363                  */
1364                 if (nr_legacy_irqs())
1365                         irq = RTC_IRQ;
1366 #endif
1367                 return cmos_do_probe(&pnp->dev,
1368                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1369         } else {
1370                 return cmos_do_probe(&pnp->dev,
1371                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1372                                 pnp_irq(pnp, 0));
1373         }
1374 }
1375
1376 static void cmos_pnp_remove(struct pnp_dev *pnp)
1377 {
1378         cmos_do_remove(&pnp->dev);
1379 }
1380
1381 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1382 {
1383         struct device *dev = &pnp->dev;
1384         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1385
1386         if (system_state == SYSTEM_POWER_OFF) {
1387                 int retval = cmos_poweroff(dev);
1388
1389                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1390                         return;
1391         }
1392
1393         cmos_do_shutdown(cmos->irq);
1394 }
1395
1396 static const struct pnp_device_id rtc_ids[] = {
1397         { .id = "PNP0b00", },
1398         { .id = "PNP0b01", },
1399         { .id = "PNP0b02", },
1400         { },
1401 };
1402 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1403
1404 static struct pnp_driver cmos_pnp_driver = {
1405         .name           = driver_name,
1406         .id_table       = rtc_ids,
1407         .probe          = cmos_pnp_probe,
1408         .remove         = cmos_pnp_remove,
1409         .shutdown       = cmos_pnp_shutdown,
1410
1411         /* flag ensures resume() gets called, and stops syslog spam */
1412         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1413         .driver         = {
1414                         .pm = &cmos_pm_ops,
1415         },
1416 };
1417
1418 #endif  /* CONFIG_PNP */
1419
1420 #ifdef CONFIG_OF
1421 static const struct of_device_id of_cmos_match[] = {
1422         {
1423                 .compatible = "motorola,mc146818",
1424         },
1425         { },
1426 };
1427 MODULE_DEVICE_TABLE(of, of_cmos_match);
1428
1429 static __init void cmos_of_init(struct platform_device *pdev)
1430 {
1431         struct device_node *node = pdev->dev.of_node;
1432         const __be32 *val;
1433
1434         if (!node)
1435                 return;
1436
1437         val = of_get_property(node, "ctrl-reg", NULL);
1438         if (val)
1439                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1440
1441         val = of_get_property(node, "freq-reg", NULL);
1442         if (val)
1443                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1444 }
1445 #else
1446 static inline void cmos_of_init(struct platform_device *pdev) {}
1447 #endif
1448 /*----------------------------------------------------------------*/
1449
1450 /* Platform setup should have set up an RTC device, when PNP is
1451  * unavailable ... this could happen even on (older) PCs.
1452  */
1453
1454 static int __init cmos_platform_probe(struct platform_device *pdev)
1455 {
1456         struct resource *resource;
1457         int irq;
1458
1459         cmos_of_init(pdev);
1460         cmos_wake_setup(&pdev->dev);
1461
1462         if (RTC_IOMAPPED)
1463                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1464         else
1465                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1466         irq = platform_get_irq(pdev, 0);
1467         if (irq < 0)
1468                 irq = -1;
1469
1470         return cmos_do_probe(&pdev->dev, resource, irq);
1471 }
1472
1473 static int cmos_platform_remove(struct platform_device *pdev)
1474 {
1475         cmos_do_remove(&pdev->dev);
1476         return 0;
1477 }
1478
1479 static void cmos_platform_shutdown(struct platform_device *pdev)
1480 {
1481         struct device *dev = &pdev->dev;
1482         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1483
1484         if (system_state == SYSTEM_POWER_OFF) {
1485                 int retval = cmos_poweroff(dev);
1486
1487                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1488                         return;
1489         }
1490
1491         cmos_do_shutdown(cmos->irq);
1492 }
1493
1494 /* work with hotplug and coldplug */
1495 MODULE_ALIAS("platform:rtc_cmos");
1496
1497 static struct platform_driver cmos_platform_driver = {
1498         .remove         = cmos_platform_remove,
1499         .shutdown       = cmos_platform_shutdown,
1500         .driver = {
1501                 .name           = driver_name,
1502                 .pm             = &cmos_pm_ops,
1503                 .of_match_table = of_match_ptr(of_cmos_match),
1504         }
1505 };
1506
1507 #ifdef CONFIG_PNP
1508 static bool pnp_driver_registered;
1509 #endif
1510 static bool platform_driver_registered;
1511
1512 static int __init cmos_init(void)
1513 {
1514         int retval = 0;
1515
1516 #ifdef  CONFIG_PNP
1517         retval = pnp_register_driver(&cmos_pnp_driver);
1518         if (retval == 0)
1519                 pnp_driver_registered = true;
1520 #endif
1521
1522         if (!cmos_rtc.dev) {
1523                 retval = platform_driver_probe(&cmos_platform_driver,
1524                                                cmos_platform_probe);
1525                 if (retval == 0)
1526                         platform_driver_registered = true;
1527         }
1528
1529         if (retval == 0)
1530                 return 0;
1531
1532 #ifdef  CONFIG_PNP
1533         if (pnp_driver_registered)
1534                 pnp_unregister_driver(&cmos_pnp_driver);
1535 #endif
1536         return retval;
1537 }
1538 module_init(cmos_init);
1539
1540 static void __exit cmos_exit(void)
1541 {
1542 #ifdef  CONFIG_PNP
1543         if (pnp_driver_registered)
1544                 pnp_unregister_driver(&cmos_pnp_driver);
1545 #endif
1546         if (platform_driver_registered)
1547                 platform_driver_unregister(&cmos_platform_driver);
1548 }
1549 module_exit(cmos_exit);
1550
1551
1552 MODULE_AUTHOR("David Brownell");
1553 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1554 MODULE_LICENSE("GPL");