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_timer_init(void)
 155 {
 156         return 0;
 157 }
 158
 159 extern irq_handler_t hpet_rtc_interrupt;
 160
 161 static inline int hpet_register_irq_handler(irq_handler_t handler)
 162 {
 163         return 0;
 164 }
 165
 166 static inline int hpet_unregister_irq_handler(irq_handler_t handler)
 167 {
 168         return 0;
 169 }
 170
 171 #endif
 172
 173 /* Don't use HPET for RTC Alarm event if ACPI Fixed event is used */
 174 static inline int use_hpet_alarm(void)
 175 {
 176         return is_hpet_enabled() && !cmos_use_acpi_alarm();
 177 }
 178
 179 /*----------------------------------------------------------------*/
 180
 181 #ifdef RTC_PORT
 182
 183 /* Most newer x86 systems have two register banks, the first used
 184  * for RTC and NVRAM and the second only for NVRAM.  Caller must
 185  * own rtc_lock ... and we won't worry about access during NMI.
 186  */
 187 #define can_bank2       true
 188
 189 static inline unsigned char cmos_read_bank2(unsigned char addr)
 190 {
 191         outb(addr, RTC_PORT(2));
 192         return inb(RTC_PORT(3));
 193 }
 194
 195 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 196 {
 197         outb(addr, RTC_PORT(2));
 198         outb(val, RTC_PORT(3));
 199 }
 200
 201 #else
 202
 203 #define can_bank2       false
 204
 205 static inline unsigned char cmos_read_bank2(unsigned char addr)
 206 {
 207         return 0;
 208 }
 209
 210 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 211 {
 212 }
 213
 214 #endif
 215
 216 /*----------------------------------------------------------------*/
 217
 218 static int cmos_read_time(struct device *dev, struct rtc_time *t)
 219 {
 220         int ret;
 221
 222         /*
 223          * If pm_trace abused the RTC for storage, set the timespec to 0,
 224          * which tells the caller that this RTC value is unusable.
 225          */
 226         if (!pm_trace_rtc_valid())
 227                 return -EIO;
 228
 229         ret = mc146818_get_time(t, 1000);
 230         if (ret < 0) {
 231                 dev_err_ratelimited(dev, "unable to read current time\n");
 232                 return ret;
 233         }
 234
 235         return 0;
 236 }
 237
 238 static int cmos_set_time(struct device *dev, struct rtc_time *t)
 239 {
 240         /* NOTE: this ignores the issue whereby updating the seconds
 241          * takes effect exactly 500ms after we write the register.
 242          * (Also queueing and other delays before we get this far.)
 243          */
 244         return mc146818_set_time(t);
 245 }
 246
 247 struct cmos_read_alarm_callback_param {
 248         struct cmos_rtc *cmos;
 249         struct rtc_time *time;
 250         unsigned char   rtc_control;
 251 };
 252
 253 static void cmos_read_alarm_callback(unsigned char __always_unused seconds,
 254                                      void *param_in)
 255 {
 256         struct cmos_read_alarm_callback_param *p =
 257                 (struct cmos_read_alarm_callback_param *)param_in;
 258         struct rtc_time *time = p->time;
 259
 260         time->tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
 261         time->tm_min = CMOS_READ(RTC_MINUTES_ALARM);
 262         time->tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 263
 264         if (p->cmos->day_alrm) {
 265                 /* ignore upper bits on readback per ACPI spec */
 266                 time->tm_mday = CMOS_READ(p->cmos->day_alrm) & 0x3f;
 267                 if (!time->tm_mday)
 268                         time->tm_mday = -1;
 269
 270                 if (p->cmos->mon_alrm) {
 271                         time->tm_mon = CMOS_READ(p->cmos->mon_alrm);
 272                         if (!time->tm_mon)
 273                                 time->tm_mon = -1;
 274                 }
 275         }
 276
 277         p->rtc_control = CMOS_READ(RTC_CONTROL);
 278 }
 279
 280 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 281 {
 282         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 283         struct cmos_read_alarm_callback_param p = {
 284                 .cmos = cmos,
 285                 .time = &t->time,
 286         };
 287
 288         /* This not only a rtc_op, but also called directly */
 289         if (!is_valid_irq(cmos->irq))
 290                 return -ETIMEDOUT;
 291
 292         /* Basic alarms only support hour, minute, and seconds fields.
 293          * Some also support day and month, for alarms up to a year in
 294          * the future.
 295          */
 296
 297         /* Some Intel chipsets disconnect the alarm registers when the clock
 298          * update is in progress - during this time reads return bogus values
 299          * and writes may fail silently. See for example "7th Generation Intel®
 300          * Processor Family I/O for U/Y Platforms [...] Datasheet", section
 301          * 27.7.1
 302          *
 303          * Use the mc146818_avoid_UIP() function to avoid this.
 304          */
 305         if (!mc146818_avoid_UIP(cmos_read_alarm_callback, 10, &p))
 306                 return -EIO;
 307
 308         if (!(p.rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 309                 if (((unsigned)t->time.tm_sec) < 0x60)
 310                         t->time.tm_sec = bcd2bin(t->time.tm_sec);
 311                 else
 312                         t->time.tm_sec = -1;
 313                 if (((unsigned)t->time.tm_min) < 0x60)
 314                         t->time.tm_min = bcd2bin(t->time.tm_min);
 315                 else
 316                         t->time.tm_min = -1;
 317                 if (((unsigned)t->time.tm_hour) < 0x24)
 318                         t->time.tm_hour = bcd2bin(t->time.tm_hour);
 319                 else
 320                         t->time.tm_hour = -1;
 321
 322                 if (cmos->day_alrm) {
 323                         if (((unsigned)t->time.tm_mday) <= 0x31)
 324                                 t->time.tm_mday = bcd2bin(t->time.tm_mday);
 325                         else
 326                                 t->time.tm_mday = -1;
 327
 328                         if (cmos->mon_alrm) {
 329                                 if (((unsigned)t->time.tm_mon) <= 0x12)
 330                                         t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
 331                                 else
 332                                         t->time.tm_mon = -1;
 333                         }
 334                 }
 335         }
 336
 337         t->enabled = !!(p.rtc_control & RTC_AIE);
 338         t->pending = 0;
 339
 340         return 0;
 341 }
 342
 343 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
 344 {
 345         unsigned char   rtc_intr;
 346
 347         /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
 348          * allegedly some older rtcs need that to handle irqs properly
 349          */
 350         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 351
 352         if (use_hpet_alarm())
 353                 return;
 354
 355         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 356         if (is_intr(rtc_intr))
 357                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
 358 }
 359
 360 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
 361 {
 362         unsigned char   rtc_control;
 363
 364         /* flush any pending IRQ status, notably for update irqs,
 365          * before we enable new IRQs
 366          */
 367         rtc_control = CMOS_READ(RTC_CONTROL);
 368         cmos_checkintr(cmos, rtc_control);
 369
 370         rtc_control |= mask;
 371         CMOS_WRITE(rtc_control, RTC_CONTROL);
 372         if (use_hpet_alarm())
 373                 hpet_set_rtc_irq_bit(mask);
 374
 375         if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
 376                 if (cmos->wake_on)
 377                         cmos->wake_on(cmos->dev);
 378         }
 379
 380         cmos_checkintr(cmos, rtc_control);
 381 }
 382
 383 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
 384 {
 385         unsigned char   rtc_control;
 386
 387         rtc_control = CMOS_READ(RTC_CONTROL);
 388         rtc_control &= ~mask;
 389         CMOS_WRITE(rtc_control, RTC_CONTROL);
 390         if (use_hpet_alarm())
 391                 hpet_mask_rtc_irq_bit(mask);
 392
 393         if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
 394                 if (cmos->wake_off)
 395                         cmos->wake_off(cmos->dev);
 396         }
 397
 398         cmos_checkintr(cmos, rtc_control);
 399 }
 400
 401 static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t)
 402 {
 403         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 404         struct rtc_time now;
 405
 406         cmos_read_time(dev, &now);
 407
 408         if (!cmos->day_alrm) {
 409                 time64_t t_max_date;
 410                 time64_t t_alrm;
 411
 412                 t_max_date = rtc_tm_to_time64(&now);
 413                 t_max_date += 24 * 60 * 60 - 1;
 414                 t_alrm = rtc_tm_to_time64(&t->time);
 415                 if (t_alrm > t_max_date) {
 416                         dev_err(dev,
 417                                 "Alarms can be up to one day in the future\n");
 418                         return -EINVAL;
 419                 }
 420         } else if (!cmos->mon_alrm) {
 421                 struct rtc_time max_date = now;
 422                 time64_t t_max_date;
 423                 time64_t t_alrm;
 424                 int max_mday;
 425
 426                 if (max_date.tm_mon == 11) {
 427                         max_date.tm_mon = 0;
 428                         max_date.tm_year += 1;
 429                 } else {
 430                         max_date.tm_mon += 1;
 431                 }
 432                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 433                 if (max_date.tm_mday > max_mday)
 434                         max_date.tm_mday = max_mday;
 435
 436                 t_max_date = rtc_tm_to_time64(&max_date);
 437                 t_max_date -= 1;
 438                 t_alrm = rtc_tm_to_time64(&t->time);
 439                 if (t_alrm > t_max_date) {
 440                         dev_err(dev,
 441                                 "Alarms can be up to one month in the future\n");
 442                         return -EINVAL;
 443                 }
 444         } else {
 445                 struct rtc_time max_date = now;
 446                 time64_t t_max_date;
 447                 time64_t t_alrm;
 448                 int max_mday;
 449
 450                 max_date.tm_year += 1;
 451                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 452                 if (max_date.tm_mday > max_mday)
 453                         max_date.tm_mday = max_mday;
 454
 455                 t_max_date = rtc_tm_to_time64(&max_date);
 456                 t_max_date -= 1;
 457                 t_alrm = rtc_tm_to_time64(&t->time);
 458                 if (t_alrm > t_max_date) {
 459                         dev_err(dev,
 460                                 "Alarms can be up to one year in the future\n");
 461                         return -EINVAL;
 462                 }
 463         }
 464
 465         return 0;
 466 }
 467
 468 struct cmos_set_alarm_callback_param {
 469         struct cmos_rtc *cmos;
 470         unsigned char mon, mday, hrs, min, sec;
 471         struct rtc_wkalrm *t;
 472 };
 473
 474 /* Note: this function may be executed by mc146818_avoid_UIP() more then
 475  *       once
 476  */
 477 static void cmos_set_alarm_callback(unsigned char __always_unused seconds,
 478                                     void *param_in)
 479 {
 480         struct cmos_set_alarm_callback_param *p =
 481                 (struct cmos_set_alarm_callback_param *)param_in;
 482
 483         /* next rtc irq must not be from previous alarm setting */
 484         cmos_irq_disable(p->cmos, RTC_AIE);
 485
 486         /* update alarm */
 487         CMOS_WRITE(p->hrs, RTC_HOURS_ALARM);
 488         CMOS_WRITE(p->min, RTC_MINUTES_ALARM);
 489         CMOS_WRITE(p->sec, RTC_SECONDS_ALARM);
 490
 491         /* the system may support an "enhanced" alarm */
 492         if (p->cmos->day_alrm) {
 493                 CMOS_WRITE(p->mday, p->cmos->day_alrm);
 494                 if (p->cmos->mon_alrm)
 495                         CMOS_WRITE(p->mon, p->cmos->mon_alrm);
 496         }
 497
 498         if (use_hpet_alarm()) {
 499                 /*
 500                  * FIXME the HPET alarm glue currently ignores day_alrm
 501                  * and mon_alrm ...
 502                  */
 503                 hpet_set_alarm_time(p->t->time.tm_hour, p->t->time.tm_min,
 504                                     p->t->time.tm_sec);
 505         }
 506
 507         if (p->t->enabled)
 508                 cmos_irq_enable(p->cmos, RTC_AIE);
 509 }
 510
 511 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 512 {
 513         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 514         struct cmos_set_alarm_callback_param p = {
 515                 .cmos = cmos,
 516                 .t = t
 517         };
 518         unsigned char rtc_control;
 519         int ret;
 520
 521         /* This not only a rtc_op, but also called directly */
 522         if (!is_valid_irq(cmos->irq))
 523                 return -EIO;
 524
 525         ret = cmos_validate_alarm(dev, t);
 526         if (ret < 0)
 527                 return ret;
 528
 529         p.mon = t->time.tm_mon + 1;
 530         p.mday = t->time.tm_mday;
 531         p.hrs = t->time.tm_hour;
 532         p.min = t->time.tm_min;
 533         p.sec = t->time.tm_sec;
 534
 535         spin_lock_irq(&rtc_lock);
 536         rtc_control = CMOS_READ(RTC_CONTROL);
 537         spin_unlock_irq(&rtc_lock);
 538
 539         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 540                 /* Writing 0xff means "don't care" or "match all".  */
 541                 p.mon = (p.mon <= 12) ? bin2bcd(p.mon) : 0xff;
 542                 p.mday = (p.mday >= 1 && p.mday <= 31) ? bin2bcd(p.mday) : 0xff;
 543                 p.hrs = (p.hrs < 24) ? bin2bcd(p.hrs) : 0xff;
 544                 p.min = (p.min < 60) ? bin2bcd(p.min) : 0xff;
 545                 p.sec = (p.sec < 60) ? bin2bcd(p.sec) : 0xff;
 546         }
 547
 548         /*
 549          * Some Intel chipsets disconnect the alarm registers when the clock
 550          * update is in progress - during this time writes fail silently.
 551          *
 552          * Use mc146818_avoid_UIP() to avoid this.
 553          */
 554         if (!mc146818_avoid_UIP(cmos_set_alarm_callback, 10, &p))
 555                 return -ETIMEDOUT;
 556
 557         cmos->alarm_expires = rtc_tm_to_time64(&t->time);
 558
 559         return 0;
 560 }
 561
 562 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 563 {
 564         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 565         unsigned long   flags;
 566
 567         spin_lock_irqsave(&rtc_lock, flags);
 568
 569         if (enabled)
 570                 cmos_irq_enable(cmos, RTC_AIE);
 571         else
 572                 cmos_irq_disable(cmos, RTC_AIE);
 573
 574         spin_unlock_irqrestore(&rtc_lock, flags);
 575         return 0;
 576 }
 577
 578 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 579
 580 static int cmos_procfs(struct device *dev, struct seq_file *seq)
 581 {
 582         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 583         unsigned char   rtc_control, valid;
 584
 585         spin_lock_irq(&rtc_lock);
 586         rtc_control = CMOS_READ(RTC_CONTROL);
 587         valid = CMOS_READ(RTC_VALID);
 588         spin_unlock_irq(&rtc_lock);
 589
 590         /* NOTE:  at least ICH6 reports battery status using a different
 591          * (non-RTC) bit; and SQWE is ignored on many current systems.
 592          */
 593         seq_printf(seq,
 594                    "periodic_IRQ\t: %s\n"
 595                    "update_IRQ\t: %s\n"
 596                    "HPET_emulated\t: %s\n"
 597                    // "square_wave\t: %s\n"
 598                    "BCD\t\t: %s\n"
 599                    "DST_enable\t: %s\n"
 600                    "periodic_freq\t: %d\n"
 601                    "batt_status\t: %s\n",
 602                    (rtc_control & RTC_PIE) ? "yes" : "no",
 603                    (rtc_control & RTC_UIE) ? "yes" : "no",
 604                    use_hpet_alarm() ? "yes" : "no",
 605                    // (rtc_control & RTC_SQWE) ? "yes" : "no",
 606                    (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 607                    (rtc_control & RTC_DST_EN) ? "yes" : "no",
 608                    cmos->rtc->irq_freq,
 609                    (valid & RTC_VRT) ? "okay" : "dead");
 610
 611         return 0;
 612 }
 613
 614 #else
 615 #define cmos_procfs     NULL
 616 #endif
 617
 618 static const struct rtc_class_ops cmos_rtc_ops = {
 619         .read_time              = cmos_read_time,
 620         .set_time               = cmos_set_time,
 621         .read_alarm             = cmos_read_alarm,
 622         .set_alarm              = cmos_set_alarm,
 623         .proc                   = cmos_procfs,
 624         .alarm_irq_enable       = cmos_alarm_irq_enable,
 625 };
 626
 627 /*----------------------------------------------------------------*/
 628
 629 /*
 630  * All these chips have at least 64 bytes of address space, shared by
 631  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 632  * by boot firmware.  Modern chips have 128 or 256 bytes.
 633  */
 634
 635 #define NVRAM_OFFSET    (RTC_REG_D + 1)
 636
 637 static int cmos_nvram_read(void *priv, unsigned int off, void *val,
 638                            size_t count)
 639 {
 640         unsigned char *buf = val;
 641
 642         off += NVRAM_OFFSET;
 643         for (; count; count--, off++, buf++) {
 644                 guard(spinlock_irq)(&rtc_lock);
 645                 if (off < 128)
 646                         *buf = CMOS_READ(off);
 647                 else if (can_bank2)
 648                         *buf = cmos_read_bank2(off);
 649                 else
 650                         return -EIO;
 651         }
 652
 653         return 0;
 654 }
 655
 656 static int cmos_nvram_write(void *priv, unsigned int off, void *val,
 657                             size_t count)
 658 {
 659         struct cmos_rtc *cmos = priv;
 660         unsigned char   *buf = val;
 661
 662         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 663          * checksum on part of the NVRAM data.  That's currently ignored
 664          * here.  If userspace is smart enough to know what fields of
 665          * NVRAM to update, updating checksums is also part of its job.
 666          */
 667         off += NVRAM_OFFSET;
 668         for (; count; count--, off++, buf++) {
 669                 /* don't trash RTC registers */
 670                 if (off == cmos->day_alrm
 671                                 || off == cmos->mon_alrm
 672                                 || off == cmos->century)
 673                         continue;
 674
 675                 guard(spinlock_irq)(&rtc_lock);
 676                 if (off < 128)
 677                         CMOS_WRITE(*buf, off);
 678                 else if (can_bank2)
 679                         cmos_write_bank2(*buf, off);
 680                 else
 681                         return -EIO;
 682         }
 683
 684         return 0;
 685 }
 686
 687 /*----------------------------------------------------------------*/
 688
 689 static struct cmos_rtc  cmos_rtc;
 690
 691 static irqreturn_t cmos_interrupt(int irq, void *p)
 692 {
 693         u8              irqstat;
 694         u8              rtc_control;
 695         unsigned long   flags;
 696
 697         /* We cannot use spin_lock() here, as cmos_interrupt() is also called
 698          * in a non-irq context.
 699          */
 700         spin_lock_irqsave(&rtc_lock, flags);
 701
 702         /* When the HPET interrupt handler calls us, the interrupt
 703          * status is passed as arg1 instead of the irq number.  But
 704          * always clear irq status, even when HPET is in the way.
 705          *
 706          * Note that HPET and RTC are almost certainly out of phase,
 707          * giving different IRQ status ...
 708          */
 709         irqstat = CMOS_READ(RTC_INTR_FLAGS);
 710         rtc_control = CMOS_READ(RTC_CONTROL);
 711         if (use_hpet_alarm())
 712                 irqstat = (unsigned long)irq & 0xF0;
 713
 714         /* If we were suspended, RTC_CONTROL may not be accurate since the
 715          * bios may have cleared it.
 716          */
 717         if (!cmos_rtc.suspend_ctrl)
 718                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 719         else
 720                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 721
 722         /* All Linux RTC alarms should be treated as if they were oneshot.
 723          * Similar code may be needed in system wakeup paths, in case the
 724          * alarm woke the system.
 725          */
 726         if (irqstat & RTC_AIE) {
 727                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 728                 rtc_control &= ~RTC_AIE;
 729                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 730                 if (use_hpet_alarm())
 731                         hpet_mask_rtc_irq_bit(RTC_AIE);
 732                 CMOS_READ(RTC_INTR_FLAGS);
 733         }
 734         spin_unlock_irqrestore(&rtc_lock, flags);
 735
 736         if (is_intr(irqstat)) {
 737                 rtc_update_irq(p, 1, irqstat);
 738                 return IRQ_HANDLED;
 739         } else
 740                 return IRQ_NONE;
 741 }
 742
 743 #ifdef  CONFIG_ACPI
 744
 745 #include <linux/acpi.h>
 746
 747 static u32 rtc_handler(void *context)
 748 {
 749         struct device *dev = context;
 750         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 751         unsigned char rtc_control = 0;
 752         unsigned char rtc_intr;
 753         unsigned long flags;
 754
 755
 756         /*
 757          * Always update rtc irq when ACPI is used as RTC Alarm.
 758          * Or else, ACPI SCI is enabled during suspend/resume only,
 759          * update rtc irq in that case.
 760          */
 761         if (cmos_use_acpi_alarm())
 762                 cmos_interrupt(0, (void *)cmos->rtc);
 763         else {
 764                 /* Fix me: can we use cmos_interrupt() here as well? */
 765                 spin_lock_irqsave(&rtc_lock, flags);
 766                 if (cmos_rtc.suspend_ctrl)
 767                         rtc_control = CMOS_READ(RTC_CONTROL);
 768                 if (rtc_control & RTC_AIE) {
 769                         cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 770                         CMOS_WRITE(rtc_control, RTC_CONTROL);
 771                         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 772                         rtc_update_irq(cmos->rtc, 1, rtc_intr);
 773                 }
 774                 spin_unlock_irqrestore(&rtc_lock, flags);
 775         }
 776
 777         pm_wakeup_hard_event(dev);
 778         acpi_clear_event(ACPI_EVENT_RTC);
 779         acpi_disable_event(ACPI_EVENT_RTC, 0);
 780         return ACPI_INTERRUPT_HANDLED;
 781 }
 782
 783 static void acpi_rtc_event_setup(struct device *dev)
 784 {
 785         if (acpi_disabled)
 786                 return;
 787
 788         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
 789         /*
 790          * After the RTC handler is installed, the Fixed_RTC event should
 791          * be disabled. Only when the RTC alarm is set will it be enabled.
 792          */
 793         acpi_clear_event(ACPI_EVENT_RTC);
 794         acpi_disable_event(ACPI_EVENT_RTC, 0);
 795 }
 796
 797 static void acpi_rtc_event_cleanup(void)
 798 {
 799         if (acpi_disabled)
 800                 return;
 801
 802         acpi_remove_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler);
 803 }
 804
 805 static void rtc_wake_on(struct device *dev)
 806 {
 807         acpi_clear_event(ACPI_EVENT_RTC);
 808         acpi_enable_event(ACPI_EVENT_RTC, 0);
 809 }
 810
 811 static void rtc_wake_off(struct device *dev)
 812 {
 813         acpi_disable_event(ACPI_EVENT_RTC, 0);
 814 }
 815
 816 #ifdef CONFIG_X86
 817 static void use_acpi_alarm_quirks(void)
 818 {
 819         switch (boot_cpu_data.x86_vendor) {
 820         case X86_VENDOR_INTEL:
 821                 if (dmi_get_bios_year() < 2015)
 822                         return;
 823                 break;
 824         case X86_VENDOR_AMD:
 825         case X86_VENDOR_HYGON:
 826                 if (dmi_get_bios_year() < 2021)
 827                         return;
 828                 break;
 829         default:
 830                 return;
 831         }
 832         if (!is_hpet_enabled())
 833                 return;
 834
 835         use_acpi_alarm = true;
 836 }
 837 #else
 838 static inline void use_acpi_alarm_quirks(void) { }
 839 #endif
 840
 841 static void acpi_cmos_wake_setup(struct device *dev)
 842 {
 843         if (acpi_disabled)
 844                 return;
 845
 846         use_acpi_alarm_quirks();
 847
 848         cmos_rtc.wake_on = rtc_wake_on;
 849         cmos_rtc.wake_off = rtc_wake_off;
 850
 851         /* ACPI tables bug workaround. */
 852         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
 853                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
 854                         acpi_gbl_FADT.month_alarm);
 855                 acpi_gbl_FADT.month_alarm = 0;
 856         }
 857
 858         cmos_rtc.day_alrm = acpi_gbl_FADT.day_alarm;
 859         cmos_rtc.mon_alrm = acpi_gbl_FADT.month_alarm;
 860         cmos_rtc.century = acpi_gbl_FADT.century;
 861
 862         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
 863                 dev_info(dev, "RTC can wake from S4\n");
 864
 865         /* RTC always wakes from S1/S2/S3, and often S4/STD */
 866         device_init_wakeup(dev, true);
 867 }
 868
 869 static void cmos_check_acpi_rtc_status(struct device *dev,
 870                                               unsigned char *rtc_control)
 871 {
 872         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 873         acpi_event_status rtc_status;
 874         acpi_status status;
 875
 876         if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
 877                 return;
 878
 879         status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
 880         if (ACPI_FAILURE(status)) {
 881                 dev_err(dev, "Could not get RTC status\n");
 882         } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
 883                 unsigned char mask;
 884                 *rtc_control &= ~RTC_AIE;
 885                 CMOS_WRITE(*rtc_control, RTC_CONTROL);
 886                 mask = CMOS_READ(RTC_INTR_FLAGS);
 887                 rtc_update_irq(cmos->rtc, 1, mask);
 888         }
 889 }
 890
 891 #else /* !CONFIG_ACPI */
 892
 893 static inline void acpi_rtc_event_setup(struct device *dev)
 894 {
 895 }
 896
 897 static inline void acpi_rtc_event_cleanup(void)
 898 {
 899 }
 900
 901 static inline void acpi_cmos_wake_setup(struct device *dev)
 902 {
 903 }
 904
 905 static inline void cmos_check_acpi_rtc_status(struct device *dev,
 906                                               unsigned char *rtc_control)
 907 {
 908 }
 909 #endif /* CONFIG_ACPI */
 910
 911 #ifdef  CONFIG_PNP
 912 #define INITSECTION
 913
 914 #else
 915 #define INITSECTION     __init
 916 #endif
 917
 918 #define SECS_PER_DAY    (24 * 60 * 60)
 919 #define SECS_PER_MONTH  (28 * SECS_PER_DAY)
 920 #define SECS_PER_YEAR   (365 * SECS_PER_DAY)
 921
 922 static int INITSECTION
 923 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 924 {
 925         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
 926         int                             retval = 0;
 927         unsigned char                   rtc_control;
 928         unsigned                        address_space;
 929         u32                             flags = 0;
 930         struct nvmem_config nvmem_cfg = {
 931                 .name = "cmos_nvram",
 932                 .word_size = 1,
 933                 .stride = 1,
 934                 .reg_read = cmos_nvram_read,
 935                 .reg_write = cmos_nvram_write,
 936                 .priv = &cmos_rtc,
 937         };
 938
 939         /* there can be only one ... */
 940         if (cmos_rtc.dev)
 941                 return -EBUSY;
 942
 943         if (!ports)
 944                 return -ENODEV;
 945
 946         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 947          *
 948          * REVISIT non-x86 systems may instead use memory space resources
 949          * (needing ioremap etc), not i/o space resources like this ...
 950          */
 951         if (RTC_IOMAPPED)
 952                 ports = request_region(ports->start, resource_size(ports),
 953                                        driver_name);
 954         else
 955                 ports = request_mem_region(ports->start, resource_size(ports),
 956                                            driver_name);
 957         if (!ports) {
 958                 dev_dbg(dev, "i/o registers already in use\n");
 959                 return -EBUSY;
 960         }
 961
 962         cmos_rtc.irq = rtc_irq;
 963         cmos_rtc.iomem = ports;
 964
 965         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 966          * driver did, but don't reject unknown configs.   Old hardware
 967          * won't address 128 bytes.  Newer chips have multiple banks,
 968          * though they may not be listed in one I/O resource.
 969          */
 970 #if     defined(CONFIG_ATARI)
 971         address_space = 64;
 972 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 973                         || defined(__sparc__) || defined(__mips__) \
 974                         || defined(__powerpc__)
 975         address_space = 128;
 976 #else
 977 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 978         address_space = 128;
 979 #endif
 980         if (can_bank2 && ports->end > (ports->start + 1))
 981                 address_space = 256;
 982
 983         /* For ACPI systems extension info comes from the FADT.  On others,
 984          * board specific setup provides it as appropriate.  Systems where
 985          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 986          * some almost-clones) can provide hooks to make that behave.
 987          *
 988          * Note that ACPI doesn't preclude putting these registers into
 989          * "extended" areas of the chip, including some that we won't yet
 990          * expect CMOS_READ and friends to handle.
 991          */
 992         if (info) {
 993                 if (info->flags)
 994                         flags = info->flags;
 995                 if (info->address_space)
 996                         address_space = info->address_space;
 997
 998                 cmos_rtc.day_alrm = info->rtc_day_alarm;
 999                 cmos_rtc.mon_alrm = info->rtc_mon_alarm;
1000                 cmos_rtc.century = info->rtc_century;
1001
1002                 if (info->wake_on && info->wake_off) {
1003                         cmos_rtc.wake_on = info->wake_on;
1004                         cmos_rtc.wake_off = info->wake_off;
1005                 }
1006         } else {
1007                 acpi_cmos_wake_setup(dev);
1008         }
1009
1010         if (cmos_rtc.day_alrm >= 128)
1011                 cmos_rtc.day_alrm = 0;
1012
1013         if (cmos_rtc.mon_alrm >= 128)
1014                 cmos_rtc.mon_alrm = 0;
1015
1016         if (cmos_rtc.century >= 128)
1017                 cmos_rtc.century = 0;
1018
1019         cmos_rtc.dev = dev;
1020         dev_set_drvdata(dev, &cmos_rtc);
1021
1022         cmos_rtc.rtc = devm_rtc_allocate_device(dev);
1023         if (IS_ERR(cmos_rtc.rtc)) {
1024                 retval = PTR_ERR(cmos_rtc.rtc);
1025                 goto cleanup0;
1026         }
1027
1028         if (cmos_rtc.mon_alrm)
1029                 cmos_rtc.rtc->alarm_offset_max = SECS_PER_YEAR - 1;
1030         else if (cmos_rtc.day_alrm)
1031                 cmos_rtc.rtc->alarm_offset_max = SECS_PER_MONTH - 1;
1032         else
1033                 cmos_rtc.rtc->alarm_offset_max = SECS_PER_DAY - 1;
1034
1035         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
1036
1037         if (!mc146818_does_rtc_work()) {
1038                 dev_warn(dev, "broken or not accessible\n");
1039                 retval = -ENXIO;
1040                 goto cleanup1;
1041         }
1042
1043         spin_lock_irq(&rtc_lock);
1044
1045         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
1046                 /* force periodic irq to CMOS reset default of 1024Hz;
1047                  *
1048                  * REVISIT it's been reported that at least one x86_64 ALI
1049                  * mobo doesn't use 32KHz here ... for portability we might
1050                  * need to do something about other clock frequencies.
1051                  */
1052                 cmos_rtc.rtc->irq_freq = 1024;
1053                 if (use_hpet_alarm())
1054                         hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
1055                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
1056         }
1057
1058         /* disable irqs */
1059         if (is_valid_irq(rtc_irq))
1060                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
1061
1062         rtc_control = CMOS_READ(RTC_CONTROL);
1063
1064         spin_unlock_irq(&rtc_lock);
1065
1066         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
1067                 dev_warn(dev, "only 24-hr supported\n");
1068                 retval = -ENXIO;
1069                 goto cleanup1;
1070         }
1071
1072         if (use_hpet_alarm())
1073                 hpet_rtc_timer_init();
1074
1075         if (is_valid_irq(rtc_irq)) {
1076                 irq_handler_t rtc_cmos_int_handler;
1077
1078                 if (use_hpet_alarm()) {
1079                         rtc_cmos_int_handler = hpet_rtc_interrupt;
1080                         retval = hpet_register_irq_handler(cmos_interrupt);
1081                         if (retval) {
1082                                 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
1083                                 dev_warn(dev, "hpet_register_irq_handler "
1084                                                 " failed in rtc_init().");
1085                                 goto cleanup1;
1086                         }
1087                 } else
1088                         rtc_cmos_int_handler = cmos_interrupt;
1089
1090                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
1091                                 0, dev_name(&cmos_rtc.rtc->dev),
1092                                 cmos_rtc.rtc);
1093                 if (retval < 0) {
1094                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
1095                         goto cleanup1;
1096                 }
1097         } else {
1098                 clear_bit(RTC_FEATURE_ALARM, cmos_rtc.rtc->features);
1099         }
1100
1101         cmos_rtc.rtc->ops = &cmos_rtc_ops;
1102
1103         retval = devm_rtc_register_device(cmos_rtc.rtc);
1104         if (retval)
1105                 goto cleanup2;
1106
1107         /* Set the sync offset for the periodic 11min update correct */
1108         cmos_rtc.rtc->set_offset_nsec = NSEC_PER_SEC / 2;
1109
1110         /* export at least the first block of NVRAM */
1111         nvmem_cfg.size = address_space - NVRAM_OFFSET;
1112         devm_rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg);
1113
1114         /*
1115          * Everything has gone well so far, so by default register a handler for
1116          * the ACPI RTC fixed event.
1117          */
1118         if (!info)
1119                 acpi_rtc_event_setup(dev);
1120
1121         dev_info(dev, "%s%s, %d bytes nvram%s\n",
1122                  !is_valid_irq(rtc_irq) ? "no alarms" :
1123                  cmos_rtc.mon_alrm ? "alarms up to one year" :
1124                  cmos_rtc.day_alrm ? "alarms up to one month" :
1125                  "alarms up to one day",
1126                  cmos_rtc.century ? ", y3k" : "",
1127                  nvmem_cfg.size,
1128                  use_hpet_alarm() ? ", hpet irqs" : "");
1129
1130         return 0;
1131
1132 cleanup2:
1133         if (is_valid_irq(rtc_irq))
1134                 free_irq(rtc_irq, cmos_rtc.rtc);
1135 cleanup1:
1136         cmos_rtc.dev = NULL;
1137 cleanup0:
1138         if (RTC_IOMAPPED)
1139                 release_region(ports->start, resource_size(ports));
1140         else
1141                 release_mem_region(ports->start, resource_size(ports));
1142         return retval;
1143 }
1144
1145 static void cmos_do_shutdown(int rtc_irq)
1146 {
1147         spin_lock_irq(&rtc_lock);
1148         if (is_valid_irq(rtc_irq))
1149                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
1150         spin_unlock_irq(&rtc_lock);
1151 }
1152
1153 static void cmos_do_remove(struct device *dev)
1154 {
1155         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1156         struct resource *ports;
1157
1158         cmos_do_shutdown(cmos->irq);
1159
1160         if (is_valid_irq(cmos->irq)) {
1161                 free_irq(cmos->irq, cmos->rtc);
1162                 if (use_hpet_alarm())
1163                         hpet_unregister_irq_handler(cmos_interrupt);
1164         }
1165
1166         if (!dev_get_platdata(dev))
1167                 acpi_rtc_event_cleanup();
1168
1169         cmos->rtc = NULL;
1170
1171         ports = cmos->iomem;
1172         if (RTC_IOMAPPED)
1173                 release_region(ports->start, resource_size(ports));
1174         else
1175                 release_mem_region(ports->start, resource_size(ports));
1176         cmos->iomem = NULL;
1177
1178         cmos->dev = NULL;
1179 }
1180
1181 static int cmos_aie_poweroff(struct device *dev)
1182 {
1183         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1184         struct rtc_time now;
1185         time64_t t_now;
1186         int retval = 0;
1187         unsigned char rtc_control;
1188
1189         if (!cmos->alarm_expires)
1190                 return -EINVAL;
1191
1192         spin_lock_irq(&rtc_lock);
1193         rtc_control = CMOS_READ(RTC_CONTROL);
1194         spin_unlock_irq(&rtc_lock);
1195
1196         /* We only care about the situation where AIE is disabled. */
1197         if (rtc_control & RTC_AIE)
1198                 return -EBUSY;
1199
1200         cmos_read_time(dev, &now);
1201         t_now = rtc_tm_to_time64(&now);
1202
1203         /*
1204          * When enabling "RTC wake-up" in BIOS setup, the machine reboots
1205          * automatically right after shutdown on some buggy boxes.
1206          * This automatic rebooting issue won't happen when the alarm
1207          * time is larger than now+1 seconds.
1208          *
1209          * If the alarm time is equal to now+1 seconds, the issue can be
1210          * prevented by cancelling the alarm.
1211          */
1212         if (cmos->alarm_expires == t_now + 1) {
1213                 struct rtc_wkalrm alarm;
1214
1215                 /* Cancel the AIE timer by configuring the past time. */
1216                 rtc_time64_to_tm(t_now - 1, &alarm.time);
1217                 alarm.enabled = 0;
1218                 retval = cmos_set_alarm(dev, &alarm);
1219         } else if (cmos->alarm_expires > t_now + 1) {
1220                 retval = -EBUSY;
1221         }
1222
1223         return retval;
1224 }
1225
1226 static int cmos_suspend(struct device *dev)
1227 {
1228         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1229         unsigned char   tmp;
1230
1231         /* only the alarm might be a wakeup event source */
1232         spin_lock_irq(&rtc_lock);
1233         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
1234         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
1235                 unsigned char   mask;
1236
1237                 if (device_may_wakeup(dev))
1238                         mask = RTC_IRQMASK & ~RTC_AIE;
1239                 else
1240                         mask = RTC_IRQMASK;
1241                 tmp &= ~mask;
1242                 CMOS_WRITE(tmp, RTC_CONTROL);
1243                 if (use_hpet_alarm())
1244                         hpet_mask_rtc_irq_bit(mask);
1245                 cmos_checkintr(cmos, tmp);
1246         }
1247         spin_unlock_irq(&rtc_lock);
1248
1249         if ((tmp & RTC_AIE) && !cmos_use_acpi_alarm()) {
1250                 cmos->enabled_wake = 1;
1251                 if (cmos->wake_on)
1252                         cmos->wake_on(dev);
1253                 else
1254                         enable_irq_wake(cmos->irq);
1255         }
1256
1257         memset(&cmos->saved_wkalrm, 0, sizeof(struct rtc_wkalrm));
1258         cmos_read_alarm(dev, &cmos->saved_wkalrm);
1259
1260         dev_dbg(dev, "suspend%s, ctrl %02x\n",
1261                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
1262                         tmp);
1263
1264         return 0;
1265 }
1266
1267 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
1268  * after a detour through G3 "mechanical off", although the ACPI spec
1269  * says wakeup should only work from G1/S4 "hibernate".  To most users,
1270  * distinctions between S4 and S5 are pointless.  So when the hardware
1271  * allows, don't draw that distinction.
1272  */
1273 static inline int cmos_poweroff(struct device *dev)
1274 {
1275         if (!IS_ENABLED(CONFIG_PM))
1276                 return -ENOSYS;
1277
1278         return cmos_suspend(dev);
1279 }
1280
1281 static void cmos_check_wkalrm(struct device *dev)
1282 {
1283         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1284         struct rtc_wkalrm current_alarm;
1285         time64_t t_now;
1286         time64_t t_current_expires;
1287         time64_t t_saved_expires;
1288         struct rtc_time now;
1289
1290         /* Check if we have RTC Alarm armed */
1291         if (!(cmos->suspend_ctrl & RTC_AIE))
1292                 return;
1293
1294         cmos_read_time(dev, &now);
1295         t_now = rtc_tm_to_time64(&now);
1296
1297         /*
1298          * ACPI RTC wake event is cleared after resume from STR,
1299          * ACK the rtc irq here
1300          */
1301         if (t_now >= cmos->alarm_expires && cmos_use_acpi_alarm()) {
1302                 cmos_interrupt(0, (void *)cmos->rtc);
1303                 return;
1304         }
1305
1306         memset(&current_alarm, 0, sizeof(struct rtc_wkalrm));
1307         cmos_read_alarm(dev, &current_alarm);
1308         t_current_expires = rtc_tm_to_time64(&current_alarm.time);
1309         t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
1310         if (t_current_expires != t_saved_expires ||
1311             cmos->saved_wkalrm.enabled != current_alarm.enabled) {
1312                 cmos_set_alarm(dev, &cmos->saved_wkalrm);
1313         }
1314 }
1315
1316 static int __maybe_unused cmos_resume(struct device *dev)
1317 {
1318         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1319         unsigned char tmp;
1320
1321         if (cmos->enabled_wake && !cmos_use_acpi_alarm()) {
1322                 if (cmos->wake_off)
1323                         cmos->wake_off(dev);
1324                 else
1325                         disable_irq_wake(cmos->irq);
1326                 cmos->enabled_wake = 0;
1327         }
1328
1329         /* The BIOS might have changed the alarm, restore it */
1330         cmos_check_wkalrm(dev);
1331
1332         spin_lock_irq(&rtc_lock);
1333         tmp = cmos->suspend_ctrl;
1334         cmos->suspend_ctrl = 0;
1335         /* re-enable any irqs previously active */
1336         if (tmp & RTC_IRQMASK) {
1337                 unsigned char   mask;
1338
1339                 if (device_may_wakeup(dev) && use_hpet_alarm())
1340                         hpet_rtc_timer_init();
1341
1342                 do {
1343                         CMOS_WRITE(tmp, RTC_CONTROL);
1344                         if (use_hpet_alarm())
1345                                 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1346
1347                         mask = CMOS_READ(RTC_INTR_FLAGS);
1348                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1349                         if (!use_hpet_alarm() || !is_intr(mask))
1350                                 break;
1351
1352                         /* force one-shot behavior if HPET blocked
1353                          * the wake alarm's irq
1354                          */
1355                         rtc_update_irq(cmos->rtc, 1, mask);
1356                         tmp &= ~RTC_AIE;
1357                         hpet_mask_rtc_irq_bit(RTC_AIE);
1358                 } while (mask & RTC_AIE);
1359
1360                 if (tmp & RTC_AIE)
1361                         cmos_check_acpi_rtc_status(dev, &tmp);
1362         }
1363         spin_unlock_irq(&rtc_lock);
1364
1365         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1366
1367         return 0;
1368 }
1369
1370 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1371
1372 /*----------------------------------------------------------------*/
1373
1374 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1375  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1376  * probably list them in similar PNPBIOS tables; so PNP is more common.
1377  *
1378  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1379  * predate even PNPBIOS should set up platform_bus devices.
1380  */
1381
1382 #ifdef  CONFIG_PNP
1383
1384 #include <linux/pnp.h>
1385
1386 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1387 {
1388         int irq;
1389
1390         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1391                 irq = 0;
1392 #ifdef CONFIG_X86
1393                 /* Some machines contain a PNP entry for the RTC, but
1394                  * don't define the IRQ. It should always be safe to
1395                  * hardcode it on systems with a legacy PIC.
1396                  */
1397                 if (nr_legacy_irqs())
1398                         irq = RTC_IRQ;
1399 #endif
1400         } else {
1401                 irq = pnp_irq(pnp, 0);
1402         }
1403
1404         return cmos_do_probe(&pnp->dev, pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1405 }
1406
1407 static void cmos_pnp_remove(struct pnp_dev *pnp)
1408 {
1409         cmos_do_remove(&pnp->dev);
1410 }
1411
1412 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1413 {
1414         struct device *dev = &pnp->dev;
1415         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1416
1417         if (system_state == SYSTEM_POWER_OFF) {
1418                 int retval = cmos_poweroff(dev);
1419
1420                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1421                         return;
1422         }
1423
1424         cmos_do_shutdown(cmos->irq);
1425 }
1426
1427 static const struct pnp_device_id rtc_ids[] = {
1428         { .id = "PNP0b00", },
1429         { .id = "PNP0b01", },
1430         { .id = "PNP0b02", },
1431         { },
1432 };
1433 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1434
1435 static struct pnp_driver cmos_pnp_driver = {
1436         .name           = driver_name,
1437         .id_table       = rtc_ids,
1438         .probe          = cmos_pnp_probe,
1439         .remove         = cmos_pnp_remove,
1440         .shutdown       = cmos_pnp_shutdown,
1441
1442         /* flag ensures resume() gets called, and stops syslog spam */
1443         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1444         .driver         = {
1445                         .pm = &cmos_pm_ops,
1446         },
1447 };
1448
1449 #endif  /* CONFIG_PNP */
1450
1451 #ifdef CONFIG_OF
1452 static const struct of_device_id of_cmos_match[] = {
1453         {
1454                 .compatible = "motorola,mc146818",
1455         },
1456         { },
1457 };
1458 MODULE_DEVICE_TABLE(of, of_cmos_match);
1459
1460 static __init void cmos_of_init(struct platform_device *pdev)
1461 {
1462         struct device_node *node = pdev->dev.of_node;
1463         const __be32 *val;
1464
1465         if (!node)
1466                 return;
1467
1468         val = of_get_property(node, "ctrl-reg", NULL);
1469         if (val)
1470                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1471
1472         val = of_get_property(node, "freq-reg", NULL);
1473         if (val)
1474                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1475 }
1476 #else
1477 static inline void cmos_of_init(struct platform_device *pdev) {}
1478 #endif
1479 /*----------------------------------------------------------------*/
1480
1481 /* Platform setup should have set up an RTC device, when PNP is
1482  * unavailable ... this could happen even on (older) PCs.
1483  */
1484
1485 static int __init cmos_platform_probe(struct platform_device *pdev)
1486 {
1487         struct resource *resource;
1488         int irq;
1489
1490         cmos_of_init(pdev);
1491
1492         if (RTC_IOMAPPED)
1493                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1494         else
1495                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1496         irq = platform_get_irq(pdev, 0);
1497         if (irq < 0)
1498                 irq = -1;
1499
1500         return cmos_do_probe(&pdev->dev, resource, irq);
1501 }
1502
1503 static void cmos_platform_remove(struct platform_device *pdev)
1504 {
1505         cmos_do_remove(&pdev->dev);
1506 }
1507
1508 static void cmos_platform_shutdown(struct platform_device *pdev)
1509 {
1510         struct device *dev = &pdev->dev;
1511         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1512
1513         if (system_state == SYSTEM_POWER_OFF) {
1514                 int retval = cmos_poweroff(dev);
1515
1516                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1517                         return;
1518         }
1519
1520         cmos_do_shutdown(cmos->irq);
1521 }
1522
1523 /* work with hotplug and coldplug */
1524 MODULE_ALIAS("platform:rtc_cmos");
1525
1526 static struct platform_driver cmos_platform_driver = {
1527         .remove         = cmos_platform_remove,
1528         .shutdown       = cmos_platform_shutdown,
1529         .driver = {
1530                 .name           = driver_name,
1531                 .pm             = &cmos_pm_ops,
1532                 .of_match_table = of_match_ptr(of_cmos_match),
1533         }
1534 };
1535
1536 #ifdef CONFIG_PNP
1537 static bool pnp_driver_registered;
1538 #endif
1539 static bool platform_driver_registered;
1540
1541 static int __init cmos_init(void)
1542 {
1543         int retval = 0;
1544
1545 #ifdef  CONFIG_PNP
1546         retval = pnp_register_driver(&cmos_pnp_driver);
1547         if (retval == 0)
1548                 pnp_driver_registered = true;
1549 #endif
1550
1551         if (!cmos_rtc.dev) {
1552                 retval = platform_driver_probe(&cmos_platform_driver,
1553                                                cmos_platform_probe);
1554                 if (retval == 0)
1555                         platform_driver_registered = true;
1556         }
1557
1558         if (retval == 0)
1559                 return 0;
1560
1561 #ifdef  CONFIG_PNP
1562         if (pnp_driver_registered)
1563                 pnp_unregister_driver(&cmos_pnp_driver);
1564 #endif
1565         return retval;
1566 }
1567 module_init(cmos_init);
1568
1569 static void __exit cmos_exit(void)
1570 {
1571 #ifdef  CONFIG_PNP
1572         if (pnp_driver_registered)
1573                 pnp_unregister_driver(&cmos_pnp_driver);
1574 #endif
1575         if (platform_driver_registered)
1576                 platform_driver_unregister(&cmos_platform_driver);
1577 }
1578 module_exit(cmos_exit);
1579
1580
1581 MODULE_AUTHOR("David Brownell");
1582 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1583 MODULE_LICENSE("GPL");