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