drivers/rtc/rtc-cmos.c

   1 /*
   2  * RTC class driver for "CMOS RTC":  PCs, ACPI, etc
   3  *
   4  * Copyright (C) 1996 Paul Gortmaker (drivers/char/rtc.c)
   5  * Copyright (C) 2006 David Brownell (convert to new framework)
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the License, or (at your option) any later version.
  11  */
  12
  13 /*
  14  * The original "cmos clock" chip was an MC146818 chip, now obsolete.
  15  * That defined the register interface now provided by all PCs, some
  16  * non-PC systems, and incorporated into ACPI.  Modern PC chipsets
  17  * integrate an MC146818 clone in their southbridge, and boards use
  18  * that instead of discrete clones like the DS12887 or M48T86.  There
  19  * are also clones that connect using the LPC bus.
  20  *
  21  * That register API is also used directly by various other drivers
  22  * (notably for integrated NVRAM), infrastructure (x86 has code to
  23  * bypass the RTC framework, directly reading the RTC during boot
  24  * and updating minutes/seconds for systems using NTP synch) and
  25  * utilities (like userspace 'hwclock', if no /dev node exists).
  26  *
  27  * So **ALL** calls to CMOS_READ and CMOS_WRITE must be done with
  28  * interrupts disabled, holding the global rtc_lock, to exclude those
  29  * other drivers and utilities on correctly configured systems.
  30  */
  31
  32 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  33
  34 #include <linux/kernel.h>
  35 #include <linux/module.h>
  36 #include <linux/init.h>
  37 #include <linux/interrupt.h>
  38 #include <linux/spinlock.h>
  39 #include <linux/platform_device.h>
  40 #include <linux/log2.h>
  41 #include <linux/pm.h>
  42 #include <linux/of.h>
  43 #include <linux/of_platform.h>
  44 #ifdef CONFIG_X86
  45 #include <asm/i8259.h>
  46 #include <asm/processor.h>
  47 #include <linux/dmi.h>
  48 #endif
  49
  50 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
  51 #include <linux/mc146818rtc.h>
  52
  53 #ifdef CONFIG_ACPI
  54 /*
  55  * Use ACPI SCI to replace HPET interrupt for RTC Alarm event
  56  *
  57  * If cleared, ACPI SCI is only used to wake up the system from suspend
  58  *
  59  * If set, ACPI SCI is used to handle UIE/AIE and system wakeup
  60  */
  61
  62 static bool use_acpi_alarm;
  63 module_param(use_acpi_alarm, bool, 0444);
  64
  65 static inline int cmos_use_acpi_alarm(void)
  66 {
  67         return use_acpi_alarm;
  68 }
  69 #else /* !CONFIG_ACPI */
  70
  71 static inline int cmos_use_acpi_alarm(void)
  72 {
  73         return 0;
  74 }
  75 #endif
  76
  77 struct cmos_rtc {
  78         struct rtc_device       *rtc;
  79         struct device           *dev;
  80         int                     irq;
  81         struct resource         *iomem;
  82         time64_t                alarm_expires;
  83
  84         void                    (*wake_on)(struct device *);
  85         void                    (*wake_off)(struct device *);
  86
  87         u8                      enabled_wake;
  88         u8                      suspend_ctrl;
  89
  90         /* newer hardware extends the original register set */
  91         u8                      day_alrm;
  92         u8                      mon_alrm;
  93         u8                      century;
  94
  95         struct rtc_wkalrm       saved_wkalrm;
  96 };
  97
  98 /* both platform and pnp busses use negative numbers for invalid irqs */
  99 #define is_valid_irq(n)         ((n) > 0)
 100
 101 static const char driver_name[] = "rtc_cmos";
 102
 103 /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
 104  * always mask it against the irq enable bits in RTC_CONTROL.  Bit values
 105  * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
 106  */
 107 #define RTC_IRQMASK     (RTC_PF | RTC_AF | RTC_UF)
 108
 109 static inline int is_intr(u8 rtc_intr)
 110 {
 111         if (!(rtc_intr & RTC_IRQF))
 112                 return 0;
 113         return rtc_intr & RTC_IRQMASK;
 114 }
 115
 116 /*----------------------------------------------------------------*/
 117
 118 /* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
 119  * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
 120  * used in a broken "legacy replacement" mode.  The breakage includes
 121  * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
 122  * other (better) use.
 123  *
 124  * When that broken mode is in use, platform glue provides a partial
 125  * emulation of hardware RTC IRQ facilities using HPET #1.  We don't
 126  * want to use HPET for anything except those IRQs though...
 127  */
 128 #ifdef CONFIG_HPET_EMULATE_RTC
 129 #include <asm/hpet.h>
 130 #else
 131
 132 static inline int is_hpet_enabled(void)
 133 {
 134         return 0;
 135 }
 136
 137 static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
 138 {
 139         return 0;
 140 }
 141
 142 static inline int hpet_set_rtc_irq_bit(unsigned long mask)
 143 {
 144         return 0;
 145 }
 146
 147 static inline int
 148 hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
 149 {
 150         return 0;
 151 }
 152
 153 static inline int hpet_set_periodic_freq(unsigned long freq)
 154 {
 155         return 0;
 156 }
 157
 158 static inline int hpet_rtc_dropped_irq(void)
 159 {
 160         return 0;
 161 }
 162
 163 static inline int hpet_rtc_timer_init(void)
 164 {
 165         return 0;
 166 }
 167
 168 extern irq_handler_t hpet_rtc_interrupt;
 169
 170 static inline int hpet_register_irq_handler(irq_handler_t handler)
 171 {
 172         return 0;
 173 }
 174
 175 static inline int hpet_unregister_irq_handler(irq_handler_t handler)
 176 {
 177         return 0;
 178 }
 179
 180 #endif
 181
 182 /* Don't use HPET for RTC Alarm event if ACPI Fixed event is used */
 183 static inline int use_hpet_alarm(void)
 184 {
 185         return is_hpet_enabled() && !cmos_use_acpi_alarm();
 186 }
 187
 188 /*----------------------------------------------------------------*/
 189
 190 #ifdef RTC_PORT
 191
 192 /* Most newer x86 systems have two register banks, the first used
 193  * for RTC and NVRAM and the second only for NVRAM.  Caller must
 194  * own rtc_lock ... and we won't worry about access during NMI.
 195  */
 196 #define can_bank2       true
 197
 198 static inline unsigned char cmos_read_bank2(unsigned char addr)
 199 {
 200         outb(addr, RTC_PORT(2));
 201         return inb(RTC_PORT(3));
 202 }
 203
 204 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 205 {
 206         outb(addr, RTC_PORT(2));
 207         outb(val, RTC_PORT(3));
 208 }
 209
 210 #else
 211
 212 #define can_bank2       false
 213
 214 static inline unsigned char cmos_read_bank2(unsigned char addr)
 215 {
 216         return 0;
 217 }
 218
 219 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 220 {
 221 }
 222
 223 #endif
 224
 225 /*----------------------------------------------------------------*/
 226
 227 static int cmos_read_time(struct device *dev, struct rtc_time *t)
 228 {
 229         /*
 230          * If pm_trace abused the RTC for storage, set the timespec to 0,
 231          * which tells the caller that this RTC value is unusable.
 232          */
 233         if (!pm_trace_rtc_valid())
 234                 return -EIO;
 235
 236         /* REVISIT:  if the clock has a "century" register, use
 237          * that instead of the heuristic in mc146818_get_time().
 238          * That'll make Y3K compatility (year > 2070) easy!
 239          */
 240         mc146818_get_time(t);
 241         return 0;
 242 }
 243
 244 static int cmos_set_time(struct device *dev, struct rtc_time *t)
 245 {
 246         /* REVISIT:  set the "century" register if available
 247          *
 248          * NOTE: this ignores the issue whereby updating the seconds
 249          * takes effect exactly 500ms after we write the register.
 250          * (Also queueing and other delays before we get this far.)
 251          */
 252         return mc146818_set_time(t);
 253 }
 254
 255 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 256 {
 257         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 258         unsigned char   rtc_control;
 259
 260         /* This not only a rtc_op, but also called directly */
 261         if (!is_valid_irq(cmos->irq))
 262                 return -EIO;
 263
 264         /* Basic alarms only support hour, minute, and seconds fields.
 265          * Some also support day and month, for alarms up to a year in
 266          * the future.
 267          */
 268
 269         spin_lock_irq(&rtc_lock);
 270         t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
 271         t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
 272         t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 273
 274         if (cmos->day_alrm) {
 275                 /* ignore upper bits on readback per ACPI spec */
 276                 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
 277                 if (!t->time.tm_mday)
 278                         t->time.tm_mday = -1;
 279
 280                 if (cmos->mon_alrm) {
 281                         t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
 282                         if (!t->time.tm_mon)
 283                                 t->time.tm_mon = -1;
 284                 }
 285         }
 286
 287         rtc_control = CMOS_READ(RTC_CONTROL);
 288         spin_unlock_irq(&rtc_lock);
 289
 290         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 291                 if (((unsigned)t->time.tm_sec) < 0x60)
 292                         t->time.tm_sec = bcd2bin(t->time.tm_sec);
 293                 else
 294                         t->time.tm_sec = -1;
 295                 if (((unsigned)t->time.tm_min) < 0x60)
 296                         t->time.tm_min = bcd2bin(t->time.tm_min);
 297                 else
 298                         t->time.tm_min = -1;
 299                 if (((unsigned)t->time.tm_hour) < 0x24)
 300                         t->time.tm_hour = bcd2bin(t->time.tm_hour);
 301                 else
 302                         t->time.tm_hour = -1;
 303
 304                 if (cmos->day_alrm) {
 305                         if (((unsigned)t->time.tm_mday) <= 0x31)
 306                                 t->time.tm_mday = bcd2bin(t->time.tm_mday);
 307                         else
 308                                 t->time.tm_mday = -1;
 309
 310                         if (cmos->mon_alrm) {
 311                                 if (((unsigned)t->time.tm_mon) <= 0x12)
 312                                         t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
 313                                 else
 314                                         t->time.tm_mon = -1;
 315                         }
 316                 }
 317         }
 318
 319         t->enabled = !!(rtc_control & RTC_AIE);
 320         t->pending = 0;
 321
 322         return 0;
 323 }
 324
 325 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
 326 {
 327         unsigned char   rtc_intr;
 328
 329         /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
 330          * allegedly some older rtcs need that to handle irqs properly
 331          */
 332         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 333
 334         if (use_hpet_alarm())
 335                 return;
 336
 337         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 338         if (is_intr(rtc_intr))
 339                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
 340 }
 341
 342 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
 343 {
 344         unsigned char   rtc_control;
 345
 346         /* flush any pending IRQ status, notably for update irqs,
 347          * before we enable new IRQs
 348          */
 349         rtc_control = CMOS_READ(RTC_CONTROL);
 350         cmos_checkintr(cmos, rtc_control);
 351
 352         rtc_control |= mask;
 353         CMOS_WRITE(rtc_control, RTC_CONTROL);
 354         if (use_hpet_alarm())
 355                 hpet_set_rtc_irq_bit(mask);
 356
 357         if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
 358                 if (cmos->wake_on)
 359                         cmos->wake_on(cmos->dev);
 360         }
 361
 362         cmos_checkintr(cmos, rtc_control);
 363 }
 364
 365 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
 366 {
 367         unsigned char   rtc_control;
 368
 369         rtc_control = CMOS_READ(RTC_CONTROL);
 370         rtc_control &= ~mask;
 371         CMOS_WRITE(rtc_control, RTC_CONTROL);
 372         if (use_hpet_alarm())
 373                 hpet_mask_rtc_irq_bit(mask);
 374
 375         if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
 376                 if (cmos->wake_off)
 377                         cmos->wake_off(cmos->dev);
 378         }
 379
 380         cmos_checkintr(cmos, rtc_control);
 381 }
 382
 383 static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t)
 384 {
 385         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 386         struct rtc_time now;
 387
 388         cmos_read_time(dev, &now);
 389
 390         if (!cmos->day_alrm) {
 391                 time64_t t_max_date;
 392                 time64_t t_alrm;
 393
 394                 t_max_date = rtc_tm_to_time64(&now);
 395                 t_max_date += 24 * 60 * 60 - 1;
 396                 t_alrm = rtc_tm_to_time64(&t->time);
 397                 if (t_alrm > t_max_date) {
 398                         dev_err(dev,
 399                                 "Alarms can be up to one day in the future\n");
 400                         return -EINVAL;
 401                 }
 402         } else if (!cmos->mon_alrm) {
 403                 struct rtc_time max_date = now;
 404                 time64_t t_max_date;
 405                 time64_t t_alrm;
 406                 int max_mday;
 407
 408                 if (max_date.tm_mon == 11) {
 409                         max_date.tm_mon = 0;
 410                         max_date.tm_year += 1;
 411                 } else {
 412                         max_date.tm_mon += 1;
 413                 }
 414                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 415                 if (max_date.tm_mday > max_mday)
 416                         max_date.tm_mday = max_mday;
 417
 418                 t_max_date = rtc_tm_to_time64(&max_date);
 419                 t_max_date -= 1;
 420                 t_alrm = rtc_tm_to_time64(&t->time);
 421                 if (t_alrm > t_max_date) {
 422                         dev_err(dev,
 423                                 "Alarms can be up to one month in the future\n");
 424                         return -EINVAL;
 425                 }
 426         } else {
 427                 struct rtc_time max_date = now;
 428                 time64_t t_max_date;
 429                 time64_t t_alrm;
 430                 int max_mday;
 431
 432                 max_date.tm_year += 1;
 433                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 434                 if (max_date.tm_mday > max_mday)
 435                         max_date.tm_mday = max_mday;
 436
 437                 t_max_date = rtc_tm_to_time64(&max_date);
 438                 t_max_date -= 1;
 439                 t_alrm = rtc_tm_to_time64(&t->time);
 440                 if (t_alrm > t_max_date) {
 441                         dev_err(dev,
 442                                 "Alarms can be up to one year in the future\n");
 443                         return -EINVAL;
 444                 }
 445         }
 446
 447         return 0;
 448 }
 449
 450 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 451 {
 452         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 453         unsigned char mon, mday, hrs, min, sec, rtc_control;
 454         int ret;
 455
 456         /* This not only a rtc_op, but also called directly */
 457         if (!is_valid_irq(cmos->irq))
 458                 return -EIO;
 459
 460         ret = cmos_validate_alarm(dev, t);
 461         if (ret < 0)
 462                 return ret;
 463
 464         mon = t->time.tm_mon + 1;
 465         mday = t->time.tm_mday;
 466         hrs = t->time.tm_hour;
 467         min = t->time.tm_min;
 468         sec = t->time.tm_sec;
 469
 470         spin_lock_irq(&rtc_lock);
 471         rtc_control = CMOS_READ(RTC_CONTROL);
 472         spin_unlock_irq(&rtc_lock);
 473
 474         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 475                 /* Writing 0xff means "don't care" or "match all".  */
 476                 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
 477                 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 478                 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
 479                 min = (min < 60) ? bin2bcd(min) : 0xff;
 480                 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
 481         }
 482
 483         spin_lock_irq(&rtc_lock);
 484
 485         /* next rtc irq must not be from previous alarm setting */
 486         cmos_irq_disable(cmos, RTC_AIE);
 487
 488         /* update alarm */
 489         CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 490         CMOS_WRITE(min, RTC_MINUTES_ALARM);
 491         CMOS_WRITE(sec, RTC_SECONDS_ALARM);
 492
 493         /* the system may support an "enhanced" alarm */
 494         if (cmos->day_alrm) {
 495                 CMOS_WRITE(mday, cmos->day_alrm);
 496                 if (cmos->mon_alrm)
 497                         CMOS_WRITE(mon, cmos->mon_alrm);
 498         }
 499
 500         if (use_hpet_alarm()) {
 501                 /*
 502                  * FIXME the HPET alarm glue currently ignores day_alrm
 503                  * and mon_alrm ...
 504                  */
 505                 hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min,
 506                                     t->time.tm_sec);
 507         }
 508
 509         if (t->enabled)
 510                 cmos_irq_enable(cmos, RTC_AIE);
 511
 512         spin_unlock_irq(&rtc_lock);
 513
 514         cmos->alarm_expires = rtc_tm_to_time64(&t->time);
 515
 516         return 0;
 517 }
 518
 519 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 520 {
 521         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 522         unsigned long   flags;
 523
 524         spin_lock_irqsave(&rtc_lock, flags);
 525
 526         if (enabled)
 527                 cmos_irq_enable(cmos, RTC_AIE);
 528         else
 529                 cmos_irq_disable(cmos, RTC_AIE);
 530
 531         spin_unlock_irqrestore(&rtc_lock, flags);
 532         return 0;
 533 }
 534
 535 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 536
 537 static int cmos_procfs(struct device *dev, struct seq_file *seq)
 538 {
 539         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 540         unsigned char   rtc_control, valid;
 541
 542         spin_lock_irq(&rtc_lock);
 543         rtc_control = CMOS_READ(RTC_CONTROL);
 544         valid = CMOS_READ(RTC_VALID);
 545         spin_unlock_irq(&rtc_lock);
 546
 547         /* NOTE:  at least ICH6 reports battery status using a different
 548          * (non-RTC) bit; and SQWE is ignored on many current systems.
 549          */
 550         seq_printf(seq,
 551                    "periodic_IRQ\t: %s\n"
 552                    "update_IRQ\t: %s\n"
 553                    "HPET_emulated\t: %s\n"
 554                    // "square_wave\t: %s\n"
 555                    "BCD\t\t: %s\n"
 556                    "DST_enable\t: %s\n"
 557                    "periodic_freq\t: %d\n"
 558                    "batt_status\t: %s\n",
 559                    (rtc_control & RTC_PIE) ? "yes" : "no",
 560                    (rtc_control & RTC_UIE) ? "yes" : "no",
 561                    use_hpet_alarm() ? "yes" : "no",
 562                    // (rtc_control & RTC_SQWE) ? "yes" : "no",
 563                    (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 564                    (rtc_control & RTC_DST_EN) ? "yes" : "no",
 565                    cmos->rtc->irq_freq,
 566                    (valid & RTC_VRT) ? "okay" : "dead");
 567
 568         return 0;
 569 }
 570
 571 #else
 572 #define cmos_procfs     NULL
 573 #endif
 574
 575 static const struct rtc_class_ops cmos_rtc_ops = {
 576         .read_time              = cmos_read_time,
 577         .set_time               = cmos_set_time,
 578         .read_alarm             = cmos_read_alarm,
 579         .set_alarm              = cmos_set_alarm,
 580         .proc                   = cmos_procfs,
 581         .alarm_irq_enable       = cmos_alarm_irq_enable,
 582 };
 583
 584 static const struct rtc_class_ops cmos_rtc_ops_no_alarm = {
 585         .read_time              = cmos_read_time,
 586         .set_time               = cmos_set_time,
 587         .proc                   = cmos_procfs,
 588 };
 589
 590 /*----------------------------------------------------------------*/
 591
 592 /*
 593  * All these chips have at least 64 bytes of address space, shared by
 594  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 595  * by boot firmware.  Modern chips have 128 or 256 bytes.
 596  */
 597
 598 #define NVRAM_OFFSET    (RTC_REG_D + 1)
 599
 600 static int cmos_nvram_read(void *priv, unsigned int off, void *val,
 601                            size_t count)
 602 {
 603         unsigned char *buf = val;
 604         int     retval;
 605
 606         off += NVRAM_OFFSET;
 607         spin_lock_irq(&rtc_lock);
 608         for (retval = 0; count; count--, off++, retval++) {
 609                 if (off < 128)
 610                         *buf++ = CMOS_READ(off);
 611                 else if (can_bank2)
 612                         *buf++ = cmos_read_bank2(off);
 613                 else
 614                         break;
 615         }
 616         spin_unlock_irq(&rtc_lock);
 617
 618         return retval;
 619 }
 620
 621 static int cmos_nvram_write(void *priv, unsigned int off, void *val,
 622                             size_t count)
 623 {
 624         struct cmos_rtc *cmos = priv;
 625         unsigned char   *buf = val;
 626         int             retval;
 627
 628         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 629          * checksum on part of the NVRAM data.  That's currently ignored
 630          * here.  If userspace is smart enough to know what fields of
 631          * NVRAM to update, updating checksums is also part of its job.
 632          */
 633         off += NVRAM_OFFSET;
 634         spin_lock_irq(&rtc_lock);
 635         for (retval = 0; count; count--, off++, retval++) {
 636                 /* don't trash RTC registers */
 637                 if (off == cmos->day_alrm
 638                                 || off == cmos->mon_alrm
 639                                 || off == cmos->century)
 640                         buf++;
 641                 else if (off < 128)
 642                         CMOS_WRITE(*buf++, off);
 643                 else if (can_bank2)
 644                         cmos_write_bank2(*buf++, off);
 645                 else
 646                         break;
 647         }
 648         spin_unlock_irq(&rtc_lock);
 649
 650         return retval;
 651 }
 652
 653 /*----------------------------------------------------------------*/
 654
 655 static struct cmos_rtc  cmos_rtc;
 656
 657 static irqreturn_t cmos_interrupt(int irq, void *p)
 658 {
 659         u8              irqstat;
 660         u8              rtc_control;
 661
 662         spin_lock(&rtc_lock);
 663
 664         /* When the HPET interrupt handler calls us, the interrupt
 665          * status is passed as arg1 instead of the irq number.  But
 666          * always clear irq status, even when HPET is in the way.
 667          *
 668          * Note that HPET and RTC are almost certainly out of phase,
 669          * giving different IRQ status ...
 670          */
 671         irqstat = CMOS_READ(RTC_INTR_FLAGS);
 672         rtc_control = CMOS_READ(RTC_CONTROL);
 673         if (use_hpet_alarm())
 674                 irqstat = (unsigned long)irq & 0xF0;
 675
 676         /* If we were suspended, RTC_CONTROL may not be accurate since the
 677          * bios may have cleared it.
 678          */
 679         if (!cmos_rtc.suspend_ctrl)
 680                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 681         else
 682                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 683
 684         /* All Linux RTC alarms should be treated as if they were oneshot.
 685          * Similar code may be needed in system wakeup paths, in case the
 686          * alarm woke the system.
 687          */
 688         if (irqstat & RTC_AIE) {
 689                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 690                 rtc_control &= ~RTC_AIE;
 691                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 692                 if (use_hpet_alarm())
 693                         hpet_mask_rtc_irq_bit(RTC_AIE);
 694                 CMOS_READ(RTC_INTR_FLAGS);
 695         }
 696         spin_unlock(&rtc_lock);
 697
 698         if (is_intr(irqstat)) {
 699                 rtc_update_irq(p, 1, irqstat);
 700                 return IRQ_HANDLED;
 701         } else
 702                 return IRQ_NONE;
 703 }
 704
 705 #ifdef  CONFIG_PNP
 706 #define INITSECTION
 707
 708 #else
 709 #define INITSECTION     __init
 710 #endif
 711
 712 static int INITSECTION
 713 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 714 {
 715         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
 716         int                             retval = 0;
 717         unsigned char                   rtc_control;
 718         unsigned                        address_space;
 719         u32                             flags = 0;
 720         struct nvmem_config nvmem_cfg = {
 721                 .name = "cmos_nvram",
 722                 .word_size = 1,
 723                 .stride = 1,
 724                 .reg_read = cmos_nvram_read,
 725                 .reg_write = cmos_nvram_write,
 726                 .priv = &cmos_rtc,
 727         };
 728
 729         /* there can be only one ... */
 730         if (cmos_rtc.dev)
 731                 return -EBUSY;
 732
 733         if (!ports)
 734                 return -ENODEV;
 735
 736         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 737          *
 738          * REVISIT non-x86 systems may instead use memory space resources
 739          * (needing ioremap etc), not i/o space resources like this ...
 740          */
 741         if (RTC_IOMAPPED)
 742                 ports = request_region(ports->start, resource_size(ports),
 743                                        driver_name);
 744         else
 745                 ports = request_mem_region(ports->start, resource_size(ports),
 746                                            driver_name);
 747         if (!ports) {
 748                 dev_dbg(dev, "i/o registers already in use\n");
 749                 return -EBUSY;
 750         }
 751
 752         cmos_rtc.irq = rtc_irq;
 753         cmos_rtc.iomem = ports;
 754
 755         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 756          * driver did, but don't reject unknown configs.   Old hardware
 757          * won't address 128 bytes.  Newer chips have multiple banks,
 758          * though they may not be listed in one I/O resource.
 759          */
 760 #if     defined(CONFIG_ATARI)
 761         address_space = 64;
 762 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 763                         || defined(__sparc__) || defined(__mips__) \
 764                         || defined(__powerpc__)
 765         address_space = 128;
 766 #else
 767 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 768         address_space = 128;
 769 #endif
 770         if (can_bank2 && ports->end > (ports->start + 1))
 771                 address_space = 256;
 772
 773         /* For ACPI systems extension info comes from the FADT.  On others,
 774          * board specific setup provides it as appropriate.  Systems where
 775          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 776          * some almost-clones) can provide hooks to make that behave.
 777          *
 778          * Note that ACPI doesn't preclude putting these registers into
 779          * "extended" areas of the chip, including some that we won't yet
 780          * expect CMOS_READ and friends to handle.
 781          */
 782         if (info) {
 783                 if (info->flags)
 784                         flags = info->flags;
 785                 if (info->address_space)
 786                         address_space = info->address_space;
 787
 788                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
 789                         cmos_rtc.day_alrm = info->rtc_day_alarm;
 790                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
 791                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
 792                 if (info->rtc_century && info->rtc_century < 128)
 793                         cmos_rtc.century = info->rtc_century;
 794
 795                 if (info->wake_on && info->wake_off) {
 796                         cmos_rtc.wake_on = info->wake_on;
 797                         cmos_rtc.wake_off = info->wake_off;
 798                 }
 799         }
 800
 801         cmos_rtc.dev = dev;
 802         dev_set_drvdata(dev, &cmos_rtc);
 803
 804         cmos_rtc.rtc = devm_rtc_allocate_device(dev);
 805         if (IS_ERR(cmos_rtc.rtc)) {
 806                 retval = PTR_ERR(cmos_rtc.rtc);
 807                 goto cleanup0;
 808         }
 809
 810         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 811
 812         spin_lock_irq(&rtc_lock);
 813
 814         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
 815                 /* force periodic irq to CMOS reset default of 1024Hz;
 816                  *
 817                  * REVISIT it's been reported that at least one x86_64 ALI
 818                  * mobo doesn't use 32KHz here ... for portability we might
 819                  * need to do something about other clock frequencies.
 820                  */
 821                 cmos_rtc.rtc->irq_freq = 1024;
 822                 if (use_hpet_alarm())
 823                         hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
 824                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
 825         }
 826
 827         /* disable irqs */
 828         if (is_valid_irq(rtc_irq))
 829                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
 830
 831         rtc_control = CMOS_READ(RTC_CONTROL);
 832
 833         spin_unlock_irq(&rtc_lock);
 834
 835         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
 836                 dev_warn(dev, "only 24-hr supported\n");
 837                 retval = -ENXIO;
 838                 goto cleanup1;
 839         }
 840
 841         if (use_hpet_alarm())
 842                 hpet_rtc_timer_init();
 843
 844         if (is_valid_irq(rtc_irq)) {
 845                 irq_handler_t rtc_cmos_int_handler;
 846
 847                 if (use_hpet_alarm()) {
 848                         rtc_cmos_int_handler = hpet_rtc_interrupt;
 849                         retval = hpet_register_irq_handler(cmos_interrupt);
 850                         if (retval) {
 851                                 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
 852                                 dev_warn(dev, "hpet_register_irq_handler "
 853                                                 " failed in rtc_init().");
 854                                 goto cleanup1;
 855                         }
 856                 } else
 857                         rtc_cmos_int_handler = cmos_interrupt;
 858
 859                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
 860                                 0, dev_name(&cmos_rtc.rtc->dev),
 861                                 cmos_rtc.rtc);
 862                 if (retval < 0) {
 863                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
 864                         goto cleanup1;
 865                 }
 866
 867                 cmos_rtc.rtc->ops = &cmos_rtc_ops;
 868         } else {
 869                 cmos_rtc.rtc->ops = &cmos_rtc_ops_no_alarm;
 870         }
 871
 872         cmos_rtc.rtc->nvram_old_abi = true;
 873         retval = rtc_register_device(cmos_rtc.rtc);
 874         if (retval)
 875                 goto cleanup2;
 876
 877         /* export at least the first block of NVRAM */
 878         nvmem_cfg.size = address_space - NVRAM_OFFSET;
 879         if (rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg))
 880                 dev_err(dev, "nvmem registration failed\n");
 881
 882         dev_info(dev, "%s%s, %d bytes nvram%s\n",
 883                  !is_valid_irq(rtc_irq) ? "no alarms" :
 884                  cmos_rtc.mon_alrm ? "alarms up to one year" :
 885                  cmos_rtc.day_alrm ? "alarms up to one month" :
 886                  "alarms up to one day",
 887                  cmos_rtc.century ? ", y3k" : "",
 888                  nvmem_cfg.size,
 889                  use_hpet_alarm() ? ", hpet irqs" : "");
 890
 891         return 0;
 892
 893 cleanup2:
 894         if (is_valid_irq(rtc_irq))
 895                 free_irq(rtc_irq, cmos_rtc.rtc);
 896 cleanup1:
 897         cmos_rtc.dev = NULL;
 898 cleanup0:
 899         if (RTC_IOMAPPED)
 900                 release_region(ports->start, resource_size(ports));
 901         else
 902                 release_mem_region(ports->start, resource_size(ports));
 903         return retval;
 904 }
 905
 906 static void cmos_do_shutdown(int rtc_irq)
 907 {
 908         spin_lock_irq(&rtc_lock);
 909         if (is_valid_irq(rtc_irq))
 910                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
 911         spin_unlock_irq(&rtc_lock);
 912 }
 913
 914 static void cmos_do_remove(struct device *dev)
 915 {
 916         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 917         struct resource *ports;
 918
 919         cmos_do_shutdown(cmos->irq);
 920
 921         if (is_valid_irq(cmos->irq)) {
 922                 free_irq(cmos->irq, cmos->rtc);
 923                 if (use_hpet_alarm())
 924                         hpet_unregister_irq_handler(cmos_interrupt);
 925         }
 926
 927         cmos->rtc = NULL;
 928
 929         ports = cmos->iomem;
 930         if (RTC_IOMAPPED)
 931                 release_region(ports->start, resource_size(ports));
 932         else
 933                 release_mem_region(ports->start, resource_size(ports));
 934         cmos->iomem = NULL;
 935
 936         cmos->dev = NULL;
 937 }
 938
 939 static int cmos_aie_poweroff(struct device *dev)
 940 {
 941         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 942         struct rtc_time now;
 943         time64_t t_now;
 944         int retval = 0;
 945         unsigned char rtc_control;
 946
 947         if (!cmos->alarm_expires)
 948                 return -EINVAL;
 949
 950         spin_lock_irq(&rtc_lock);
 951         rtc_control = CMOS_READ(RTC_CONTROL);
 952         spin_unlock_irq(&rtc_lock);
 953
 954         /* We only care about the situation where AIE is disabled. */
 955         if (rtc_control & RTC_AIE)
 956                 return -EBUSY;
 957
 958         cmos_read_time(dev, &now);
 959         t_now = rtc_tm_to_time64(&now);
 960
 961         /*
 962          * When enabling "RTC wake-up" in BIOS setup, the machine reboots
 963          * automatically right after shutdown on some buggy boxes.
 964          * This automatic rebooting issue won't happen when the alarm
 965          * time is larger than now+1 seconds.
 966          *
 967          * If the alarm time is equal to now+1 seconds, the issue can be
 968          * prevented by cancelling the alarm.
 969          */
 970         if (cmos->alarm_expires == t_now + 1) {
 971                 struct rtc_wkalrm alarm;
 972
 973                 /* Cancel the AIE timer by configuring the past time. */
 974                 rtc_time64_to_tm(t_now - 1, &alarm.time);
 975                 alarm.enabled = 0;
 976                 retval = cmos_set_alarm(dev, &alarm);
 977         } else if (cmos->alarm_expires > t_now + 1) {
 978                 retval = -EBUSY;
 979         }
 980
 981         return retval;
 982 }
 983
 984 static int cmos_suspend(struct device *dev)
 985 {
 986         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 987         unsigned char   tmp;
 988
 989         /* only the alarm might be a wakeup event source */
 990         spin_lock_irq(&rtc_lock);
 991         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
 992         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 993                 unsigned char   mask;
 994
 995                 if (device_may_wakeup(dev))
 996                         mask = RTC_IRQMASK & ~RTC_AIE;
 997                 else
 998                         mask = RTC_IRQMASK;
 999                 tmp &= ~mask;
1000                 CMOS_WRITE(tmp, RTC_CONTROL);
1001                 if (use_hpet_alarm())
1002                         hpet_mask_rtc_irq_bit(mask);
1003                 cmos_checkintr(cmos, tmp);
1004         }
1005         spin_unlock_irq(&rtc_lock);
1006
1007         if ((tmp & RTC_AIE) && !cmos_use_acpi_alarm()) {
1008                 cmos->enabled_wake = 1;
1009                 if (cmos->wake_on)
1010                         cmos->wake_on(dev);
1011                 else
1012                         enable_irq_wake(cmos->irq);
1013         }
1014
1015         cmos_read_alarm(dev, &cmos->saved_wkalrm);
1016
1017         dev_dbg(dev, "suspend%s, ctrl %02x\n",
1018                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
1019                         tmp);
1020
1021         return 0;
1022 }
1023
1024 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
1025  * after a detour through G3 "mechanical off", although the ACPI spec
1026  * says wakeup should only work from G1/S4 "hibernate".  To most users,
1027  * distinctions between S4 and S5 are pointless.  So when the hardware
1028  * allows, don't draw that distinction.
1029  */
1030 static inline int cmos_poweroff(struct device *dev)
1031 {
1032         if (!IS_ENABLED(CONFIG_PM))
1033                 return -ENOSYS;
1034
1035         return cmos_suspend(dev);
1036 }
1037
1038 static void cmos_check_wkalrm(struct device *dev)
1039 {
1040         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1041         struct rtc_wkalrm current_alarm;
1042         time64_t t_now;
1043         time64_t t_current_expires;
1044         time64_t t_saved_expires;
1045         struct rtc_time now;
1046
1047         /* Check if we have RTC Alarm armed */
1048         if (!(cmos->suspend_ctrl & RTC_AIE))
1049                 return;
1050
1051         cmos_read_time(dev, &now);
1052         t_now = rtc_tm_to_time64(&now);
1053
1054         /*
1055          * ACPI RTC wake event is cleared after resume from STR,
1056          * ACK the rtc irq here
1057          */
1058         if (t_now >= cmos->alarm_expires && cmos_use_acpi_alarm()) {
1059                 cmos_interrupt(0, (void *)cmos->rtc);
1060                 return;
1061         }
1062
1063         cmos_read_alarm(dev, &current_alarm);
1064         t_current_expires = rtc_tm_to_time64(&current_alarm.time);
1065         t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
1066         if (t_current_expires != t_saved_expires ||
1067             cmos->saved_wkalrm.enabled != current_alarm.enabled) {
1068                 cmos_set_alarm(dev, &cmos->saved_wkalrm);
1069         }
1070 }
1071
1072 static void cmos_check_acpi_rtc_status(struct device *dev,
1073                                        unsigned char *rtc_control);
1074
1075 static int __maybe_unused cmos_resume(struct device *dev)
1076 {
1077         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1078         unsigned char tmp;
1079
1080         if (cmos->enabled_wake && !cmos_use_acpi_alarm()) {
1081                 if (cmos->wake_off)
1082                         cmos->wake_off(dev);
1083                 else
1084                         disable_irq_wake(cmos->irq);
1085                 cmos->enabled_wake = 0;
1086         }
1087
1088         /* The BIOS might have changed the alarm, restore it */
1089         cmos_check_wkalrm(dev);
1090
1091         spin_lock_irq(&rtc_lock);
1092         tmp = cmos->suspend_ctrl;
1093         cmos->suspend_ctrl = 0;
1094         /* re-enable any irqs previously active */
1095         if (tmp & RTC_IRQMASK) {
1096                 unsigned char   mask;
1097
1098                 if (device_may_wakeup(dev) && use_hpet_alarm())
1099                         hpet_rtc_timer_init();
1100
1101                 do {
1102                         CMOS_WRITE(tmp, RTC_CONTROL);
1103                         if (use_hpet_alarm())
1104                                 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1105
1106                         mask = CMOS_READ(RTC_INTR_FLAGS);
1107                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1108                         if (!use_hpet_alarm() || !is_intr(mask))
1109                                 break;
1110
1111                         /* force one-shot behavior if HPET blocked
1112                          * the wake alarm's irq
1113                          */
1114                         rtc_update_irq(cmos->rtc, 1, mask);
1115                         tmp &= ~RTC_AIE;
1116                         hpet_mask_rtc_irq_bit(RTC_AIE);
1117                 } while (mask & RTC_AIE);
1118
1119                 if (tmp & RTC_AIE)
1120                         cmos_check_acpi_rtc_status(dev, &tmp);
1121         }
1122         spin_unlock_irq(&rtc_lock);
1123
1124         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1125
1126         return 0;
1127 }
1128
1129 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1130
1131 /*----------------------------------------------------------------*/
1132
1133 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1134  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1135  * probably list them in similar PNPBIOS tables; so PNP is more common.
1136  *
1137  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1138  * predate even PNPBIOS should set up platform_bus devices.
1139  */
1140
1141 #ifdef  CONFIG_ACPI
1142
1143 #include <linux/acpi.h>
1144
1145 static u32 rtc_handler(void *context)
1146 {
1147         struct device *dev = context;
1148         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1149         unsigned char rtc_control = 0;
1150         unsigned char rtc_intr;
1151         unsigned long flags;
1152
1153
1154         /*
1155          * Always update rtc irq when ACPI is used as RTC Alarm.
1156          * Or else, ACPI SCI is enabled during suspend/resume only,
1157          * update rtc irq in that case.
1158          */
1159         if (cmos_use_acpi_alarm())
1160                 cmos_interrupt(0, (void *)cmos->rtc);
1161         else {
1162                 /* Fix me: can we use cmos_interrupt() here as well? */
1163                 spin_lock_irqsave(&rtc_lock, flags);
1164                 if (cmos_rtc.suspend_ctrl)
1165                         rtc_control = CMOS_READ(RTC_CONTROL);
1166                 if (rtc_control & RTC_AIE) {
1167                         cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1168                         CMOS_WRITE(rtc_control, RTC_CONTROL);
1169                         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1170                         rtc_update_irq(cmos->rtc, 1, rtc_intr);
1171                 }
1172                 spin_unlock_irqrestore(&rtc_lock, flags);
1173         }
1174
1175         pm_wakeup_hard_event(dev);
1176         acpi_clear_event(ACPI_EVENT_RTC);
1177         acpi_disable_event(ACPI_EVENT_RTC, 0);
1178         return ACPI_INTERRUPT_HANDLED;
1179 }
1180
1181 static inline void rtc_wake_setup(struct device *dev)
1182 {
1183         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1184         /*
1185          * After the RTC handler is installed, the Fixed_RTC event should
1186          * be disabled. Only when the RTC alarm is set will it be enabled.
1187          */
1188         acpi_clear_event(ACPI_EVENT_RTC);
1189         acpi_disable_event(ACPI_EVENT_RTC, 0);
1190 }
1191
1192 static void rtc_wake_on(struct device *dev)
1193 {
1194         acpi_clear_event(ACPI_EVENT_RTC);
1195         acpi_enable_event(ACPI_EVENT_RTC, 0);
1196 }
1197
1198 static void rtc_wake_off(struct device *dev)
1199 {
1200         acpi_disable_event(ACPI_EVENT_RTC, 0);
1201 }
1202
1203 #ifdef CONFIG_X86
1204 /* Enable use_acpi_alarm mode for Intel platforms no earlier than 2015 */
1205 static void use_acpi_alarm_quirks(void)
1206 {
1207         int year;
1208
1209         if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
1210                 return;
1211
1212         if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
1213                 return;
1214
1215         if (!is_hpet_enabled())
1216                 return;
1217
1218         if (dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL) && year >= 2015)
1219                 use_acpi_alarm = true;
1220 }
1221 #else
1222 static inline void use_acpi_alarm_quirks(void) { }
1223 #endif
1224
1225 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1226  * its device node and pass extra config data.  This helps its driver use
1227  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1228  * that this board's RTC is wakeup-capable (per ACPI spec).
1229  */
1230 static struct cmos_rtc_board_info acpi_rtc_info;
1231
1232 static void cmos_wake_setup(struct device *dev)
1233 {
1234         if (acpi_disabled)
1235                 return;
1236
1237         use_acpi_alarm_quirks();
1238
1239         rtc_wake_setup(dev);
1240         acpi_rtc_info.wake_on = rtc_wake_on;
1241         acpi_rtc_info.wake_off = rtc_wake_off;
1242
1243         /* workaround bug in some ACPI tables */
1244         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1245                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1246                         acpi_gbl_FADT.month_alarm);
1247                 acpi_gbl_FADT.month_alarm = 0;
1248         }
1249
1250         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1251         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1252         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1253
1254         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1255         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1256                 dev_info(dev, "RTC can wake from S4\n");
1257
1258         dev->platform_data = &acpi_rtc_info;
1259
1260         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1261         device_init_wakeup(dev, 1);
1262 }
1263
1264 static void cmos_check_acpi_rtc_status(struct device *dev,
1265                                        unsigned char *rtc_control)
1266 {
1267         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1268         acpi_event_status rtc_status;
1269         acpi_status status;
1270
1271         if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1272                 return;
1273
1274         status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1275         if (ACPI_FAILURE(status)) {
1276                 dev_err(dev, "Could not get RTC status\n");
1277         } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1278                 unsigned char mask;
1279                 *rtc_control &= ~RTC_AIE;
1280                 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1281                 mask = CMOS_READ(RTC_INTR_FLAGS);
1282                 rtc_update_irq(cmos->rtc, 1, mask);
1283         }
1284 }
1285
1286 #else
1287
1288 static void cmos_wake_setup(struct device *dev)
1289 {
1290 }
1291
1292 static void cmos_check_acpi_rtc_status(struct device *dev,
1293                                        unsigned char *rtc_control)
1294 {
1295 }
1296
1297 #endif
1298
1299 #ifdef  CONFIG_PNP
1300
1301 #include <linux/pnp.h>
1302
1303 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1304 {
1305         cmos_wake_setup(&pnp->dev);
1306
1307         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1308                 unsigned int irq = 0;
1309 #ifdef CONFIG_X86
1310                 /* Some machines contain a PNP entry for the RTC, but
1311                  * don't define the IRQ. It should always be safe to
1312                  * hardcode it on systems with a legacy PIC.
1313                  */
1314                 if (nr_legacy_irqs())
1315                         irq = 8;
1316 #endif
1317                 return cmos_do_probe(&pnp->dev,
1318                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1319         } else {
1320                 return cmos_do_probe(&pnp->dev,
1321                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1322                                 pnp_irq(pnp, 0));
1323         }
1324 }
1325
1326 static void cmos_pnp_remove(struct pnp_dev *pnp)
1327 {
1328         cmos_do_remove(&pnp->dev);
1329 }
1330
1331 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1332 {
1333         struct device *dev = &pnp->dev;
1334         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1335
1336         if (system_state == SYSTEM_POWER_OFF) {
1337                 int retval = cmos_poweroff(dev);
1338
1339                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1340                         return;
1341         }
1342
1343         cmos_do_shutdown(cmos->irq);
1344 }
1345
1346 static const struct pnp_device_id rtc_ids[] = {
1347         { .id = "PNP0b00", },
1348         { .id = "PNP0b01", },
1349         { .id = "PNP0b02", },
1350         { },
1351 };
1352 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1353
1354 static struct pnp_driver cmos_pnp_driver = {
1355         .name           = (char *) driver_name,
1356         .id_table       = rtc_ids,
1357         .probe          = cmos_pnp_probe,
1358         .remove         = cmos_pnp_remove,
1359         .shutdown       = cmos_pnp_shutdown,
1360
1361         /* flag ensures resume() gets called, and stops syslog spam */
1362         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1363         .driver         = {
1364                         .pm = &cmos_pm_ops,
1365         },
1366 };
1367
1368 #endif  /* CONFIG_PNP */
1369
1370 #ifdef CONFIG_OF
1371 static const struct of_device_id of_cmos_match[] = {
1372         {
1373                 .compatible = "motorola,mc146818",
1374         },
1375         { },
1376 };
1377 MODULE_DEVICE_TABLE(of, of_cmos_match);
1378
1379 static __init void cmos_of_init(struct platform_device *pdev)
1380 {
1381         struct device_node *node = pdev->dev.of_node;
1382         const __be32 *val;
1383
1384         if (!node)
1385                 return;
1386
1387         val = of_get_property(node, "ctrl-reg", NULL);
1388         if (val)
1389                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1390
1391         val = of_get_property(node, "freq-reg", NULL);
1392         if (val)
1393                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1394 }
1395 #else
1396 static inline void cmos_of_init(struct platform_device *pdev) {}
1397 #endif
1398 /*----------------------------------------------------------------*/
1399
1400 /* Platform setup should have set up an RTC device, when PNP is
1401  * unavailable ... this could happen even on (older) PCs.
1402  */
1403
1404 static int __init cmos_platform_probe(struct platform_device *pdev)
1405 {
1406         struct resource *resource;
1407         int irq;
1408
1409         cmos_of_init(pdev);
1410         cmos_wake_setup(&pdev->dev);
1411
1412         if (RTC_IOMAPPED)
1413                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1414         else
1415                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1416         irq = platform_get_irq(pdev, 0);
1417         if (irq < 0)
1418                 irq = -1;
1419
1420         return cmos_do_probe(&pdev->dev, resource, irq);
1421 }
1422
1423 static int cmos_platform_remove(struct platform_device *pdev)
1424 {
1425         cmos_do_remove(&pdev->dev);
1426         return 0;
1427 }
1428
1429 static void cmos_platform_shutdown(struct platform_device *pdev)
1430 {
1431         struct device *dev = &pdev->dev;
1432         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1433
1434         if (system_state == SYSTEM_POWER_OFF) {
1435                 int retval = cmos_poweroff(dev);
1436
1437                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1438                         return;
1439         }
1440
1441         cmos_do_shutdown(cmos->irq);
1442 }
1443
1444 /* work with hotplug and coldplug */
1445 MODULE_ALIAS("platform:rtc_cmos");
1446
1447 static struct platform_driver cmos_platform_driver = {
1448         .remove         = cmos_platform_remove,
1449         .shutdown       = cmos_platform_shutdown,
1450         .driver = {
1451                 .name           = driver_name,
1452                 .pm             = &cmos_pm_ops,
1453                 .of_match_table = of_match_ptr(of_cmos_match),
1454         }
1455 };
1456
1457 #ifdef CONFIG_PNP
1458 static bool pnp_driver_registered;
1459 #endif
1460 static bool platform_driver_registered;
1461
1462 static int __init cmos_init(void)
1463 {
1464         int retval = 0;
1465
1466 #ifdef  CONFIG_PNP
1467         retval = pnp_register_driver(&cmos_pnp_driver);
1468         if (retval == 0)
1469                 pnp_driver_registered = true;
1470 #endif
1471
1472         if (!cmos_rtc.dev) {
1473                 retval = platform_driver_probe(&cmos_platform_driver,
1474                                                cmos_platform_probe);
1475                 if (retval == 0)
1476                         platform_driver_registered = true;
1477         }
1478
1479         if (retval == 0)
1480                 return 0;
1481
1482 #ifdef  CONFIG_PNP
1483         if (pnp_driver_registered)
1484                 pnp_unregister_driver(&cmos_pnp_driver);
1485 #endif
1486         return retval;
1487 }
1488 module_init(cmos_init);
1489
1490 static void __exit cmos_exit(void)
1491 {
1492 #ifdef  CONFIG_PNP
1493         if (pnp_driver_registered)
1494                 pnp_unregister_driver(&cmos_pnp_driver);
1495 #endif
1496         if (platform_driver_registered)
1497                 platform_driver_unregister(&cmos_platform_driver);
1498 }
1499 module_exit(cmos_exit);
1500
1501
1502 MODULE_AUTHOR("David Brownell");
1503 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1504 MODULE_LICENSE("GPL");