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, 1000);
 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 -ETIMEDOUT;
 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, 10, &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, 10, &p))
 560                 return -ETIMEDOUT;
 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
 647         off += NVRAM_OFFSET;
 648         for (; count; count--, off++, buf++) {
 649                 guard(spinlock_irq)(&rtc_lock);
 650                 if (off < 128)
 651                         *buf = CMOS_READ(off);
 652                 else if (can_bank2)
 653                         *buf = cmos_read_bank2(off);
 654                 else
 655                         return -EIO;
 656         }
 657
 658         return 0;
 659 }
 660
 661 static int cmos_nvram_write(void *priv, unsigned int off, void *val,
 662                             size_t count)
 663 {
 664         struct cmos_rtc *cmos = priv;
 665         unsigned char   *buf = val;
 666
 667         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 668          * checksum on part of the NVRAM data.  That's currently ignored
 669          * here.  If userspace is smart enough to know what fields of
 670          * NVRAM to update, updating checksums is also part of its job.
 671          */
 672         off += NVRAM_OFFSET;
 673         for (; count; count--, off++, buf++) {
 674                 /* don't trash RTC registers */
 675                 if (off == cmos->day_alrm
 676                                 || off == cmos->mon_alrm
 677                                 || off == cmos->century)
 678                         continue;
 679
 680                 guard(spinlock_irq)(&rtc_lock);
 681                 if (off < 128)
 682                         CMOS_WRITE(*buf, off);
 683                 else if (can_bank2)
 684                         cmos_write_bank2(*buf, off);
 685                 else
 686                         return -EIO;
 687         }
 688
 689         return 0;
 690 }
 691
 692 /*----------------------------------------------------------------*/
 693
 694 static struct cmos_rtc  cmos_rtc;
 695
 696 static irqreturn_t cmos_interrupt(int irq, void *p)
 697 {
 698         u8              irqstat;
 699         u8              rtc_control;
 700
 701         spin_lock(&rtc_lock);
 702
 703         /* When the HPET interrupt handler calls us, the interrupt
 704          * status is passed as arg1 instead of the irq number.  But
 705          * always clear irq status, even when HPET is in the way.
 706          *
 707          * Note that HPET and RTC are almost certainly out of phase,
 708          * giving different IRQ status ...
 709          */
 710         irqstat = CMOS_READ(RTC_INTR_FLAGS);
 711         rtc_control = CMOS_READ(RTC_CONTROL);
 712         if (use_hpet_alarm())
 713                 irqstat = (unsigned long)irq & 0xF0;
 714
 715         /* If we were suspended, RTC_CONTROL may not be accurate since the
 716          * bios may have cleared it.
 717          */
 718         if (!cmos_rtc.suspend_ctrl)
 719                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 720         else
 721                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 722
 723         /* All Linux RTC alarms should be treated as if they were oneshot.
 724          * Similar code may be needed in system wakeup paths, in case the
 725          * alarm woke the system.
 726          */
 727         if (irqstat & RTC_AIE) {
 728                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 729                 rtc_control &= ~RTC_AIE;
 730                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 731                 if (use_hpet_alarm())
 732                         hpet_mask_rtc_irq_bit(RTC_AIE);
 733                 CMOS_READ(RTC_INTR_FLAGS);
 734         }
 735         spin_unlock(&rtc_lock);
 736
 737         if (is_intr(irqstat)) {
 738                 rtc_update_irq(p, 1, irqstat);
 739                 return IRQ_HANDLED;
 740         } else
 741                 return IRQ_NONE;
 742 }
 743
 744 #ifdef  CONFIG_ACPI
 745
 746 #include <linux/acpi.h>
 747
 748 static u32 rtc_handler(void *context)
 749 {
 750         struct device *dev = context;
 751         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 752         unsigned char rtc_control = 0;
 753         unsigned char rtc_intr;
 754         unsigned long flags;
 755
 756
 757         /*
 758          * Always update rtc irq when ACPI is used as RTC Alarm.
 759          * Or else, ACPI SCI is enabled during suspend/resume only,
 760          * update rtc irq in that case.
 761          */
 762         if (cmos_use_acpi_alarm())
 763                 cmos_interrupt(0, (void *)cmos->rtc);
 764         else {
 765                 /* Fix me: can we use cmos_interrupt() here as well? */
 766                 spin_lock_irqsave(&rtc_lock, flags);
 767                 if (cmos_rtc.suspend_ctrl)
 768                         rtc_control = CMOS_READ(RTC_CONTROL);
 769                 if (rtc_control & RTC_AIE) {
 770                         cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 771                         CMOS_WRITE(rtc_control, RTC_CONTROL);
 772                         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 773                         rtc_update_irq(cmos->rtc, 1, rtc_intr);
 774                 }
 775                 spin_unlock_irqrestore(&rtc_lock, flags);
 776         }
 777
 778         pm_wakeup_hard_event(dev);
 779         acpi_clear_event(ACPI_EVENT_RTC);
 780         acpi_disable_event(ACPI_EVENT_RTC, 0);
 781         return ACPI_INTERRUPT_HANDLED;
 782 }
 783
 784 static void acpi_rtc_event_setup(struct device *dev)
 785 {
 786         if (acpi_disabled)
 787                 return;
 788
 789         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
 790         /*
 791          * After the RTC handler is installed, the Fixed_RTC event should
 792          * be disabled. Only when the RTC alarm is set will it be enabled.
 793          */
 794         acpi_clear_event(ACPI_EVENT_RTC);
 795         acpi_disable_event(ACPI_EVENT_RTC, 0);
 796 }
 797
 798 static void acpi_rtc_event_cleanup(void)
 799 {
 800         if (acpi_disabled)
 801                 return;
 802
 803         acpi_remove_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler);
 804 }
 805
 806 static void rtc_wake_on(struct device *dev)
 807 {
 808         acpi_clear_event(ACPI_EVENT_RTC);
 809         acpi_enable_event(ACPI_EVENT_RTC, 0);
 810 }
 811
 812 static void rtc_wake_off(struct device *dev)
 813 {
 814         acpi_disable_event(ACPI_EVENT_RTC, 0);
 815 }
 816
 817 #ifdef CONFIG_X86
 818 static void use_acpi_alarm_quirks(void)
 819 {
 820         switch (boot_cpu_data.x86_vendor) {
 821         case X86_VENDOR_INTEL:
 822                 if (dmi_get_bios_year() < 2015)
 823                         return;
 824                 break;
 825         case X86_VENDOR_AMD:
 826         case X86_VENDOR_HYGON:
 827                 if (dmi_get_bios_year() < 2021)
 828                         return;
 829                 break;
 830         default:
 831                 return;
 832         }
 833         if (!is_hpet_enabled())
 834                 return;
 835
 836         use_acpi_alarm = true;
 837 }
 838 #else
 839 static inline void use_acpi_alarm_quirks(void) { }
 840 #endif
 841
 842 static void acpi_cmos_wake_setup(struct device *dev)
 843 {
 844         if (acpi_disabled)
 845                 return;
 846
 847         use_acpi_alarm_quirks();
 848
 849         cmos_rtc.wake_on = rtc_wake_on;
 850         cmos_rtc.wake_off = rtc_wake_off;
 851
 852         /* ACPI tables bug workaround. */
 853         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
 854                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
 855                         acpi_gbl_FADT.month_alarm);
 856                 acpi_gbl_FADT.month_alarm = 0;
 857         }
 858
 859         cmos_rtc.day_alrm = acpi_gbl_FADT.day_alarm;
 860         cmos_rtc.mon_alrm = acpi_gbl_FADT.month_alarm;
 861         cmos_rtc.century = acpi_gbl_FADT.century;
 862
 863         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
 864                 dev_info(dev, "RTC can wake from S4\n");
 865
 866         /* RTC always wakes from S1/S2/S3, and often S4/STD */
 867         device_init_wakeup(dev, 1);
 868 }
 869
 870 static void cmos_check_acpi_rtc_status(struct device *dev,
 871                                               unsigned char *rtc_control)
 872 {
 873         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 874         acpi_event_status rtc_status;
 875         acpi_status status;
 876
 877         if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
 878                 return;
 879
 880         status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
 881         if (ACPI_FAILURE(status)) {
 882                 dev_err(dev, "Could not get RTC status\n");
 883         } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
 884                 unsigned char mask;
 885                 *rtc_control &= ~RTC_AIE;
 886                 CMOS_WRITE(*rtc_control, RTC_CONTROL);
 887                 mask = CMOS_READ(RTC_INTR_FLAGS);
 888                 rtc_update_irq(cmos->rtc, 1, mask);
 889         }
 890 }
 891
 892 #else /* !CONFIG_ACPI */
 893
 894 static inline void acpi_rtc_event_setup(struct device *dev)
 895 {
 896 }
 897
 898 static inline void acpi_rtc_event_cleanup(void)
 899 {
 900 }
 901
 902 static inline void acpi_cmos_wake_setup(struct device *dev)
 903 {
 904 }
 905
 906 static inline void cmos_check_acpi_rtc_status(struct device *dev,
 907                                               unsigned char *rtc_control)
 908 {
 909 }
 910 #endif /* CONFIG_ACPI */
 911
 912 #ifdef  CONFIG_PNP
 913 #define INITSECTION
 914
 915 #else
 916 #define INITSECTION     __init
 917 #endif
 918
 919 #define SECS_PER_DAY    (24 * 60 * 60)
 920 #define SECS_PER_MONTH  (28 * SECS_PER_DAY)
 921 #define SECS_PER_YEAR   (365 * SECS_PER_DAY)
 922
 923 static int INITSECTION
 924 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 925 {
 926         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
 927         int                             retval = 0;
 928         unsigned char                   rtc_control;
 929         unsigned                        address_space;
 930         u32                             flags = 0;
 931         struct nvmem_config nvmem_cfg = {
 932                 .name = "cmos_nvram",
 933                 .word_size = 1,
 934                 .stride = 1,
 935                 .reg_read = cmos_nvram_read,
 936                 .reg_write = cmos_nvram_write,
 937                 .priv = &cmos_rtc,
 938         };
 939
 940         /* there can be only one ... */
 941         if (cmos_rtc.dev)
 942                 return -EBUSY;
 943
 944         if (!ports)
 945                 return -ENODEV;
 946
 947         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 948          *
 949          * REVISIT non-x86 systems may instead use memory space resources
 950          * (needing ioremap etc), not i/o space resources like this ...
 951          */
 952         if (RTC_IOMAPPED)
 953                 ports = request_region(ports->start, resource_size(ports),
 954                                        driver_name);
 955         else
 956                 ports = request_mem_region(ports->start, resource_size(ports),
 957                                            driver_name);
 958         if (!ports) {
 959                 dev_dbg(dev, "i/o registers already in use\n");
 960                 return -EBUSY;
 961         }
 962
 963         cmos_rtc.irq = rtc_irq;
 964         cmos_rtc.iomem = ports;
 965
 966         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 967          * driver did, but don't reject unknown configs.   Old hardware
 968          * won't address 128 bytes.  Newer chips have multiple banks,
 969          * though they may not be listed in one I/O resource.
 970          */
 971 #if     defined(CONFIG_ATARI)
 972         address_space = 64;
 973 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 974                         || defined(__sparc__) || defined(__mips__) \
 975                         || defined(__powerpc__)
 976         address_space = 128;
 977 #else
 978 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 979         address_space = 128;
 980 #endif
 981         if (can_bank2 && ports->end > (ports->start + 1))
 982                 address_space = 256;
 983
 984         /* For ACPI systems extension info comes from the FADT.  On others,
 985          * board specific setup provides it as appropriate.  Systems where
 986          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 987          * some almost-clones) can provide hooks to make that behave.
 988          *
 989          * Note that ACPI doesn't preclude putting these registers into
 990          * "extended" areas of the chip, including some that we won't yet
 991          * expect CMOS_READ and friends to handle.
 992          */
 993         if (info) {
 994                 if (info->flags)
 995                         flags = info->flags;
 996                 if (info->address_space)
 997                         address_space = info->address_space;
 998
 999                 cmos_rtc.day_alrm = info->rtc_day_alarm;
1000                 cmos_rtc.mon_alrm = info->rtc_mon_alarm;
1001                 cmos_rtc.century = info->rtc_century;
1002
1003                 if (info->wake_on && info->wake_off) {
1004                         cmos_rtc.wake_on = info->wake_on;
1005                         cmos_rtc.wake_off = info->wake_off;
1006                 }
1007         } else {
1008                 acpi_cmos_wake_setup(dev);
1009         }
1010
1011         if (cmos_rtc.day_alrm >= 128)
1012                 cmos_rtc.day_alrm = 0;
1013
1014         if (cmos_rtc.mon_alrm >= 128)
1015                 cmos_rtc.mon_alrm = 0;
1016
1017         if (cmos_rtc.century >= 128)
1018                 cmos_rtc.century = 0;
1019
1020         cmos_rtc.dev = dev;
1021         dev_set_drvdata(dev, &cmos_rtc);
1022
1023         cmos_rtc.rtc = devm_rtc_allocate_device(dev);
1024         if (IS_ERR(cmos_rtc.rtc)) {
1025                 retval = PTR_ERR(cmos_rtc.rtc);
1026                 goto cleanup0;
1027         }
1028
1029         if (cmos_rtc.mon_alrm)
1030                 cmos_rtc.rtc->alarm_offset_max = SECS_PER_YEAR - 1;
1031         else if (cmos_rtc.day_alrm)
1032                 cmos_rtc.rtc->alarm_offset_max = SECS_PER_MONTH - 1;
1033         else
1034                 cmos_rtc.rtc->alarm_offset_max = SECS_PER_DAY - 1;
1035
1036         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
1037
1038         if (!mc146818_does_rtc_work()) {
1039                 dev_warn(dev, "broken or not accessible\n");
1040                 retval = -ENXIO;
1041                 goto cleanup1;
1042         }
1043
1044         spin_lock_irq(&rtc_lock);
1045
1046         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
1047                 /* force periodic irq to CMOS reset default of 1024Hz;
1048                  *
1049                  * REVISIT it's been reported that at least one x86_64 ALI
1050                  * mobo doesn't use 32KHz here ... for portability we might
1051                  * need to do something about other clock frequencies.
1052                  */
1053                 cmos_rtc.rtc->irq_freq = 1024;
1054                 if (use_hpet_alarm())
1055                         hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
1056                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
1057         }
1058
1059         /* disable irqs */
1060         if (is_valid_irq(rtc_irq))
1061                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
1062
1063         rtc_control = CMOS_READ(RTC_CONTROL);
1064
1065         spin_unlock_irq(&rtc_lock);
1066
1067         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
1068                 dev_warn(dev, "only 24-hr supported\n");
1069                 retval = -ENXIO;
1070                 goto cleanup1;
1071         }
1072
1073         if (use_hpet_alarm())
1074                 hpet_rtc_timer_init();
1075
1076         if (is_valid_irq(rtc_irq)) {
1077                 irq_handler_t rtc_cmos_int_handler;
1078
1079                 if (use_hpet_alarm()) {
1080                         rtc_cmos_int_handler = hpet_rtc_interrupt;
1081                         retval = hpet_register_irq_handler(cmos_interrupt);
1082                         if (retval) {
1083                                 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
1084                                 dev_warn(dev, "hpet_register_irq_handler "
1085                                                 " failed in rtc_init().");
1086                                 goto cleanup1;
1087                         }
1088                 } else
1089                         rtc_cmos_int_handler = cmos_interrupt;
1090
1091                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
1092                                 0, dev_name(&cmos_rtc.rtc->dev),
1093                                 cmos_rtc.rtc);
1094                 if (retval < 0) {
1095                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
1096                         goto cleanup1;
1097                 }
1098         } else {
1099                 clear_bit(RTC_FEATURE_ALARM, cmos_rtc.rtc->features);
1100         }
1101
1102         cmos_rtc.rtc->ops = &cmos_rtc_ops;
1103
1104         retval = devm_rtc_register_device(cmos_rtc.rtc);
1105         if (retval)
1106                 goto cleanup2;
1107
1108         /* Set the sync offset for the periodic 11min update correct */
1109         cmos_rtc.rtc->set_offset_nsec = NSEC_PER_SEC / 2;
1110
1111         /* export at least the first block of NVRAM */
1112         nvmem_cfg.size = address_space - NVRAM_OFFSET;
1113         devm_rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg);
1114
1115         /*
1116          * Everything has gone well so far, so by default register a handler for
1117          * the ACPI RTC fixed event.
1118          */
1119         if (!info)
1120                 acpi_rtc_event_setup(dev);
1121
1122         dev_info(dev, "%s%s, %d bytes nvram%s\n",
1123                  !is_valid_irq(rtc_irq) ? "no alarms" :
1124                  cmos_rtc.mon_alrm ? "alarms up to one year" :
1125                  cmos_rtc.day_alrm ? "alarms up to one month" :
1126                  "alarms up to one day",
1127                  cmos_rtc.century ? ", y3k" : "",
1128                  nvmem_cfg.size,
1129                  use_hpet_alarm() ? ", hpet irqs" : "");
1130
1131         return 0;
1132
1133 cleanup2:
1134         if (is_valid_irq(rtc_irq))
1135                 free_irq(rtc_irq, cmos_rtc.rtc);
1136 cleanup1:
1137         cmos_rtc.dev = NULL;
1138 cleanup0:
1139         if (RTC_IOMAPPED)
1140                 release_region(ports->start, resource_size(ports));
1141         else
1142                 release_mem_region(ports->start, resource_size(ports));
1143         return retval;
1144 }
1145
1146 static void cmos_do_shutdown(int rtc_irq)
1147 {
1148         spin_lock_irq(&rtc_lock);
1149         if (is_valid_irq(rtc_irq))
1150                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
1151         spin_unlock_irq(&rtc_lock);
1152 }
1153
1154 static void cmos_do_remove(struct device *dev)
1155 {
1156         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1157         struct resource *ports;
1158
1159         cmos_do_shutdown(cmos->irq);
1160
1161         if (is_valid_irq(cmos->irq)) {
1162                 free_irq(cmos->irq, cmos->rtc);
1163                 if (use_hpet_alarm())
1164                         hpet_unregister_irq_handler(cmos_interrupt);
1165         }
1166
1167         if (!dev_get_platdata(dev))
1168                 acpi_rtc_event_cleanup();
1169
1170         cmos->rtc = NULL;
1171
1172         ports = cmos->iomem;
1173         if (RTC_IOMAPPED)
1174                 release_region(ports->start, resource_size(ports));
1175         else
1176                 release_mem_region(ports->start, resource_size(ports));
1177         cmos->iomem = NULL;
1178
1179         cmos->dev = NULL;
1180 }
1181
1182 static int cmos_aie_poweroff(struct device *dev)
1183 {
1184         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1185         struct rtc_time now;
1186         time64_t t_now;
1187         int retval = 0;
1188         unsigned char rtc_control;
1189
1190         if (!cmos->alarm_expires)
1191                 return -EINVAL;
1192
1193         spin_lock_irq(&rtc_lock);
1194         rtc_control = CMOS_READ(RTC_CONTROL);
1195         spin_unlock_irq(&rtc_lock);
1196
1197         /* We only care about the situation where AIE is disabled. */
1198         if (rtc_control & RTC_AIE)
1199                 return -EBUSY;
1200
1201         cmos_read_time(dev, &now);
1202         t_now = rtc_tm_to_time64(&now);
1203
1204         /*
1205          * When enabling "RTC wake-up" in BIOS setup, the machine reboots
1206          * automatically right after shutdown on some buggy boxes.
1207          * This automatic rebooting issue won't happen when the alarm
1208          * time is larger than now+1 seconds.
1209          *
1210          * If the alarm time is equal to now+1 seconds, the issue can be
1211          * prevented by cancelling the alarm.
1212          */
1213         if (cmos->alarm_expires == t_now + 1) {
1214                 struct rtc_wkalrm alarm;
1215
1216                 /* Cancel the AIE timer by configuring the past time. */
1217                 rtc_time64_to_tm(t_now - 1, &alarm.time);
1218                 alarm.enabled = 0;
1219                 retval = cmos_set_alarm(dev, &alarm);
1220         } else if (cmos->alarm_expires > t_now + 1) {
1221                 retval = -EBUSY;
1222         }
1223
1224         return retval;
1225 }
1226
1227 static int cmos_suspend(struct device *dev)
1228 {
1229         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1230         unsigned char   tmp;
1231
1232         /* only the alarm might be a wakeup event source */
1233         spin_lock_irq(&rtc_lock);
1234         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
1235         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
1236                 unsigned char   mask;
1237
1238                 if (device_may_wakeup(dev))
1239                         mask = RTC_IRQMASK & ~RTC_AIE;
1240                 else
1241                         mask = RTC_IRQMASK;
1242                 tmp &= ~mask;
1243                 CMOS_WRITE(tmp, RTC_CONTROL);
1244                 if (use_hpet_alarm())
1245                         hpet_mask_rtc_irq_bit(mask);
1246                 cmos_checkintr(cmos, tmp);
1247         }
1248         spin_unlock_irq(&rtc_lock);
1249
1250         if ((tmp & RTC_AIE) && !cmos_use_acpi_alarm()) {
1251                 cmos->enabled_wake = 1;
1252                 if (cmos->wake_on)
1253                         cmos->wake_on(dev);
1254                 else
1255                         enable_irq_wake(cmos->irq);
1256         }
1257
1258         memset(&cmos->saved_wkalrm, 0, sizeof(struct rtc_wkalrm));
1259         cmos_read_alarm(dev, &cmos->saved_wkalrm);
1260
1261         dev_dbg(dev, "suspend%s, ctrl %02x\n",
1262                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
1263                         tmp);
1264
1265         return 0;
1266 }
1267
1268 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
1269  * after a detour through G3 "mechanical off", although the ACPI spec
1270  * says wakeup should only work from G1/S4 "hibernate".  To most users,
1271  * distinctions between S4 and S5 are pointless.  So when the hardware
1272  * allows, don't draw that distinction.
1273  */
1274 static inline int cmos_poweroff(struct device *dev)
1275 {
1276         if (!IS_ENABLED(CONFIG_PM))
1277                 return -ENOSYS;
1278
1279         return cmos_suspend(dev);
1280 }
1281
1282 static void cmos_check_wkalrm(struct device *dev)
1283 {
1284         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1285         struct rtc_wkalrm current_alarm;
1286         time64_t t_now;
1287         time64_t t_current_expires;
1288         time64_t t_saved_expires;
1289         struct rtc_time now;
1290
1291         /* Check if we have RTC Alarm armed */
1292         if (!(cmos->suspend_ctrl & RTC_AIE))
1293                 return;
1294
1295         cmos_read_time(dev, &now);
1296         t_now = rtc_tm_to_time64(&now);
1297
1298         /*
1299          * ACPI RTC wake event is cleared after resume from STR,
1300          * ACK the rtc irq here
1301          */
1302         if (t_now >= cmos->alarm_expires && cmos_use_acpi_alarm()) {
1303                 local_irq_disable();
1304                 cmos_interrupt(0, (void *)cmos->rtc);
1305                 local_irq_enable();
1306                 return;
1307         }
1308
1309         memset(&current_alarm, 0, sizeof(struct rtc_wkalrm));
1310         cmos_read_alarm(dev, &current_alarm);
1311         t_current_expires = rtc_tm_to_time64(&current_alarm.time);
1312         t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
1313         if (t_current_expires != t_saved_expires ||
1314             cmos->saved_wkalrm.enabled != current_alarm.enabled) {
1315                 cmos_set_alarm(dev, &cmos->saved_wkalrm);
1316         }
1317 }
1318
1319 static int __maybe_unused cmos_resume(struct device *dev)
1320 {
1321         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1322         unsigned char tmp;
1323
1324         if (cmos->enabled_wake && !cmos_use_acpi_alarm()) {
1325                 if (cmos->wake_off)
1326                         cmos->wake_off(dev);
1327                 else
1328                         disable_irq_wake(cmos->irq);
1329                 cmos->enabled_wake = 0;
1330         }
1331
1332         /* The BIOS might have changed the alarm, restore it */
1333         cmos_check_wkalrm(dev);
1334
1335         spin_lock_irq(&rtc_lock);
1336         tmp = cmos->suspend_ctrl;
1337         cmos->suspend_ctrl = 0;
1338         /* re-enable any irqs previously active */
1339         if (tmp & RTC_IRQMASK) {
1340                 unsigned char   mask;
1341
1342                 if (device_may_wakeup(dev) && use_hpet_alarm())
1343                         hpet_rtc_timer_init();
1344
1345                 do {
1346                         CMOS_WRITE(tmp, RTC_CONTROL);
1347                         if (use_hpet_alarm())
1348                                 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1349
1350                         mask = CMOS_READ(RTC_INTR_FLAGS);
1351                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1352                         if (!use_hpet_alarm() || !is_intr(mask))
1353                                 break;
1354
1355                         /* force one-shot behavior if HPET blocked
1356                          * the wake alarm's irq
1357                          */
1358                         rtc_update_irq(cmos->rtc, 1, mask);
1359                         tmp &= ~RTC_AIE;
1360                         hpet_mask_rtc_irq_bit(RTC_AIE);
1361                 } while (mask & RTC_AIE);
1362
1363                 if (tmp & RTC_AIE)
1364                         cmos_check_acpi_rtc_status(dev, &tmp);
1365         }
1366         spin_unlock_irq(&rtc_lock);
1367
1368         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1369
1370         return 0;
1371 }
1372
1373 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1374
1375 /*----------------------------------------------------------------*/
1376
1377 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1378  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1379  * probably list them in similar PNPBIOS tables; so PNP is more common.
1380  *
1381  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1382  * predate even PNPBIOS should set up platform_bus devices.
1383  */
1384
1385 #ifdef  CONFIG_PNP
1386
1387 #include <linux/pnp.h>
1388
1389 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1390 {
1391         int irq;
1392
1393         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1394                 irq = 0;
1395 #ifdef CONFIG_X86
1396                 /* Some machines contain a PNP entry for the RTC, but
1397                  * don't define the IRQ. It should always be safe to
1398                  * hardcode it on systems with a legacy PIC.
1399                  */
1400                 if (nr_legacy_irqs())
1401                         irq = RTC_IRQ;
1402 #endif
1403         } else {
1404                 irq = pnp_irq(pnp, 0);
1405         }
1406
1407         return cmos_do_probe(&pnp->dev, pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1408 }
1409
1410 static void cmos_pnp_remove(struct pnp_dev *pnp)
1411 {
1412         cmos_do_remove(&pnp->dev);
1413 }
1414
1415 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1416 {
1417         struct device *dev = &pnp->dev;
1418         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1419
1420         if (system_state == SYSTEM_POWER_OFF) {
1421                 int retval = cmos_poweroff(dev);
1422
1423                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1424                         return;
1425         }
1426
1427         cmos_do_shutdown(cmos->irq);
1428 }
1429
1430 static const struct pnp_device_id rtc_ids[] = {
1431         { .id = "PNP0b00", },
1432         { .id = "PNP0b01", },
1433         { .id = "PNP0b02", },
1434         { },
1435 };
1436 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1437
1438 static struct pnp_driver cmos_pnp_driver = {
1439         .name           = driver_name,
1440         .id_table       = rtc_ids,
1441         .probe          = cmos_pnp_probe,
1442         .remove         = cmos_pnp_remove,
1443         .shutdown       = cmos_pnp_shutdown,
1444
1445         /* flag ensures resume() gets called, and stops syslog spam */
1446         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1447         .driver         = {
1448                         .pm = &cmos_pm_ops,
1449         },
1450 };
1451
1452 #endif  /* CONFIG_PNP */
1453
1454 #ifdef CONFIG_OF
1455 static const struct of_device_id of_cmos_match[] = {
1456         {
1457                 .compatible = "motorola,mc146818",
1458         },
1459         { },
1460 };
1461 MODULE_DEVICE_TABLE(of, of_cmos_match);
1462
1463 static __init void cmos_of_init(struct platform_device *pdev)
1464 {
1465         struct device_node *node = pdev->dev.of_node;
1466         const __be32 *val;
1467
1468         if (!node)
1469                 return;
1470
1471         val = of_get_property(node, "ctrl-reg", NULL);
1472         if (val)
1473                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1474
1475         val = of_get_property(node, "freq-reg", NULL);
1476         if (val)
1477                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1478 }
1479 #else
1480 static inline void cmos_of_init(struct platform_device *pdev) {}
1481 #endif
1482 /*----------------------------------------------------------------*/
1483
1484 /* Platform setup should have set up an RTC device, when PNP is
1485  * unavailable ... this could happen even on (older) PCs.
1486  */
1487
1488 static int __init cmos_platform_probe(struct platform_device *pdev)
1489 {
1490         struct resource *resource;
1491         int irq;
1492
1493         cmos_of_init(pdev);
1494
1495         if (RTC_IOMAPPED)
1496                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1497         else
1498                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1499         irq = platform_get_irq(pdev, 0);
1500         if (irq < 0)
1501                 irq = -1;
1502
1503         return cmos_do_probe(&pdev->dev, resource, irq);
1504 }
1505
1506 static void cmos_platform_remove(struct platform_device *pdev)
1507 {
1508         cmos_do_remove(&pdev->dev);
1509 }
1510
1511 static void cmos_platform_shutdown(struct platform_device *pdev)
1512 {
1513         struct device *dev = &pdev->dev;
1514         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1515
1516         if (system_state == SYSTEM_POWER_OFF) {
1517                 int retval = cmos_poweroff(dev);
1518
1519                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1520                         return;
1521         }
1522
1523         cmos_do_shutdown(cmos->irq);
1524 }
1525
1526 /* work with hotplug and coldplug */
1527 MODULE_ALIAS("platform:rtc_cmos");
1528
1529 static struct platform_driver cmos_platform_driver = {
1530         .remove         = cmos_platform_remove,
1531         .shutdown       = cmos_platform_shutdown,
1532         .driver = {
1533                 .name           = driver_name,
1534                 .pm             = &cmos_pm_ops,
1535                 .of_match_table = of_match_ptr(of_cmos_match),
1536         }
1537 };
1538
1539 #ifdef CONFIG_PNP
1540 static bool pnp_driver_registered;
1541 #endif
1542 static bool platform_driver_registered;
1543
1544 static int __init cmos_init(void)
1545 {
1546         int retval = 0;
1547
1548 #ifdef  CONFIG_PNP
1549         retval = pnp_register_driver(&cmos_pnp_driver);
1550         if (retval == 0)
1551                 pnp_driver_registered = true;
1552 #endif
1553
1554         if (!cmos_rtc.dev) {
1555                 retval = platform_driver_probe(&cmos_platform_driver,
1556                                                cmos_platform_probe);
1557                 if (retval == 0)
1558                         platform_driver_registered = true;
1559         }
1560
1561         if (retval == 0)
1562                 return 0;
1563
1564 #ifdef  CONFIG_PNP
1565         if (pnp_driver_registered)
1566                 pnp_unregister_driver(&cmos_pnp_driver);
1567 #endif
1568         return retval;
1569 }
1570 module_init(cmos_init);
1571
1572 static void __exit cmos_exit(void)
1573 {
1574 #ifdef  CONFIG_PNP
1575         if (pnp_driver_registered)
1576                 pnp_unregister_driver(&cmos_pnp_driver);
1577 #endif
1578         if (platform_driver_registered)
1579                 platform_driver_unregister(&cmos_platform_driver);
1580 }
1581 module_exit(cmos_exit);
1582
1583
1584 MODULE_AUTHOR("David Brownell");
1585 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1586 MODULE_LICENSE("GPL");