drivers/rtc/rtc-cmos.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * RTC class driver for "CMOS RTC":  PCs, ACPI, etc
   4  *
   5  * Copyright (C) 1996 Paul Gortmaker (drivers/char/rtc.c)
   6  * Copyright (C) 2006 David Brownell (convert to new framework)
   7  */
   8
   9 /*
  10  * The original "cmos clock" chip was an MC146818 chip, now obsolete.
  11  * That defined the register interface now provided by all PCs, some
  12  * non-PC systems, and incorporated into ACPI.  Modern PC chipsets
  13  * integrate an MC146818 clone in their southbridge, and boards use
  14  * that instead of discrete clones like the DS12887 or M48T86.  There
  15  * are also clones that connect using the LPC bus.
  16  *
  17  * That register API is also used directly by various other drivers
  18  * (notably for integrated NVRAM), infrastructure (x86 has code to
  19  * bypass the RTC framework, directly reading the RTC during boot
  20  * and updating minutes/seconds for systems using NTP synch) and
  21  * utilities (like userspace 'hwclock', if no /dev node exists).
  22  *
  23  * So **ALL** calls to CMOS_READ and CMOS_WRITE must be done with
  24  * interrupts disabled, holding the global rtc_lock, to exclude those
  25  * other drivers and utilities on correctly configured systems.
  26  */
  27
  28 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  29
  30 #include <linux/kernel.h>
  31 #include <linux/module.h>
  32 #include <linux/init.h>
  33 #include <linux/interrupt.h>
  34 #include <linux/spinlock.h>
  35 #include <linux/platform_device.h>
  36 #include <linux/log2.h>
  37 #include <linux/pm.h>
  38 #include <linux/of.h>
  39 #include <linux/of_platform.h>
  40 #ifdef CONFIG_X86
  41 #include <asm/i8259.h>
  42 #include <asm/processor.h>
  43 #include <linux/dmi.h>
  44 #endif
  45
  46 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
  47 #include <linux/mc146818rtc.h>
  48
  49 #ifdef CONFIG_ACPI
  50 /*
  51  * Use ACPI SCI to replace HPET interrupt for RTC Alarm event
  52  *
  53  * If cleared, ACPI SCI is only used to wake up the system from suspend
  54  *
  55  * If set, ACPI SCI is used to handle UIE/AIE and system wakeup
  56  */
  57
  58 static bool use_acpi_alarm;
  59 module_param(use_acpi_alarm, bool, 0444);
  60
  61 static inline int cmos_use_acpi_alarm(void)
  62 {
  63         return use_acpi_alarm;
  64 }
  65 #else /* !CONFIG_ACPI */
  66
  67 static inline int cmos_use_acpi_alarm(void)
  68 {
  69         return 0;
  70 }
  71 #endif
  72
  73 struct cmos_rtc {
  74         struct rtc_device       *rtc;
  75         struct device           *dev;
  76         int                     irq;
  77         struct resource         *iomem;
  78         time64_t                alarm_expires;
  79
  80         void                    (*wake_on)(struct device *);
  81         void                    (*wake_off)(struct device *);
  82
  83         u8                      enabled_wake;
  84         u8                      suspend_ctrl;
  85
  86         /* newer hardware extends the original register set */
  87         u8                      day_alrm;
  88         u8                      mon_alrm;
  89         u8                      century;
  90
  91         struct rtc_wkalrm       saved_wkalrm;
  92 };
  93
  94 /* both platform and pnp busses use negative numbers for invalid irqs */
  95 #define is_valid_irq(n)         ((n) > 0)
  96
  97 static const char driver_name[] = "rtc_cmos";
  98
  99 /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
 100  * always mask it against the irq enable bits in RTC_CONTROL.  Bit values
 101  * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
 102  */
 103 #define RTC_IRQMASK     (RTC_PF | RTC_AF | RTC_UF)
 104
 105 static inline int is_intr(u8 rtc_intr)
 106 {
 107         if (!(rtc_intr & RTC_IRQF))
 108                 return 0;
 109         return rtc_intr & RTC_IRQMASK;
 110 }
 111
 112 /*----------------------------------------------------------------*/
 113
 114 /* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
 115  * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
 116  * used in a broken "legacy replacement" mode.  The breakage includes
 117  * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
 118  * other (better) use.
 119  *
 120  * When that broken mode is in use, platform glue provides a partial
 121  * emulation of hardware RTC IRQ facilities using HPET #1.  We don't
 122  * want to use HPET for anything except those IRQs though...
 123  */
 124 #ifdef CONFIG_HPET_EMULATE_RTC
 125 #include <asm/hpet.h>
 126 #else
 127
 128 static inline int is_hpet_enabled(void)
 129 {
 130         return 0;
 131 }
 132
 133 static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
 134 {
 135         return 0;
 136 }
 137
 138 static inline int hpet_set_rtc_irq_bit(unsigned long mask)
 139 {
 140         return 0;
 141 }
 142
 143 static inline int
 144 hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
 145 {
 146         return 0;
 147 }
 148
 149 static inline int hpet_set_periodic_freq(unsigned long freq)
 150 {
 151         return 0;
 152 }
 153
 154 static inline int hpet_rtc_dropped_irq(void)
 155 {
 156         return 0;
 157 }
 158
 159 static inline int hpet_rtc_timer_init(void)
 160 {
 161         return 0;
 162 }
 163
 164 extern irq_handler_t hpet_rtc_interrupt;
 165
 166 static inline int hpet_register_irq_handler(irq_handler_t handler)
 167 {
 168         return 0;
 169 }
 170
 171 static inline int hpet_unregister_irq_handler(irq_handler_t handler)
 172 {
 173         return 0;
 174 }
 175
 176 #endif
 177
 178 /* Don't use HPET for RTC Alarm event if ACPI Fixed event is used */
 179 static inline int use_hpet_alarm(void)
 180 {
 181         return is_hpet_enabled() && !cmos_use_acpi_alarm();
 182 }
 183
 184 /*----------------------------------------------------------------*/
 185
 186 #ifdef RTC_PORT
 187
 188 /* Most newer x86 systems have two register banks, the first used
 189  * for RTC and NVRAM and the second only for NVRAM.  Caller must
 190  * own rtc_lock ... and we won't worry about access during NMI.
 191  */
 192 #define can_bank2       true
 193
 194 static inline unsigned char cmos_read_bank2(unsigned char addr)
 195 {
 196         outb(addr, RTC_PORT(2));
 197         return inb(RTC_PORT(3));
 198 }
 199
 200 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 201 {
 202         outb(addr, RTC_PORT(2));
 203         outb(val, RTC_PORT(3));
 204 }
 205
 206 #else
 207
 208 #define can_bank2       false
 209
 210 static inline unsigned char cmos_read_bank2(unsigned char addr)
 211 {
 212         return 0;
 213 }
 214
 215 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 216 {
 217 }
 218
 219 #endif
 220
 221 /*----------------------------------------------------------------*/
 222
 223 static int cmos_read_time(struct device *dev, struct rtc_time *t)
 224 {
 225         int ret;
 226
 227         /*
 228          * If pm_trace abused the RTC for storage, set the timespec to 0,
 229          * which tells the caller that this RTC value is unusable.
 230          */
 231         if (!pm_trace_rtc_valid())
 232                 return -EIO;
 233
 234         ret = mc146818_get_time(t);
 235         if (ret < 0) {
 236                 dev_err_ratelimited(dev, "unable to read current time\n");
 237                 return ret;
 238         }
 239
 240         return 0;
 241 }
 242
 243 static int cmos_set_time(struct device *dev, struct rtc_time *t)
 244 {
 245         /* NOTE: this ignores the issue whereby updating the seconds
 246          * takes effect exactly 500ms after we write the register.
 247          * (Also queueing and other delays before we get this far.)
 248          */
 249         return mc146818_set_time(t);
 250 }
 251
 252 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 253 {
 254         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 255         unsigned char   rtc_control;
 256
 257         /* This not only a rtc_op, but also called directly */
 258         if (!is_valid_irq(cmos->irq))
 259                 return -EIO;
 260
 261         /* Basic alarms only support hour, minute, and seconds fields.
 262          * Some also support day and month, for alarms up to a year in
 263          * the future.
 264          */
 265
 266         spin_lock_irq(&rtc_lock);
 267         t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
 268         t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
 269         t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 270
 271         if (cmos->day_alrm) {
 272                 /* ignore upper bits on readback per ACPI spec */
 273                 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
 274                 if (!t->time.tm_mday)
 275                         t->time.tm_mday = -1;
 276
 277                 if (cmos->mon_alrm) {
 278                         t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
 279                         if (!t->time.tm_mon)
 280                                 t->time.tm_mon = -1;
 281                 }
 282         }
 283
 284         rtc_control = CMOS_READ(RTC_CONTROL);
 285         spin_unlock_irq(&rtc_lock);
 286
 287         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 288                 if (((unsigned)t->time.tm_sec) < 0x60)
 289                         t->time.tm_sec = bcd2bin(t->time.tm_sec);
 290                 else
 291                         t->time.tm_sec = -1;
 292                 if (((unsigned)t->time.tm_min) < 0x60)
 293                         t->time.tm_min = bcd2bin(t->time.tm_min);
 294                 else
 295                         t->time.tm_min = -1;
 296                 if (((unsigned)t->time.tm_hour) < 0x24)
 297                         t->time.tm_hour = bcd2bin(t->time.tm_hour);
 298                 else
 299                         t->time.tm_hour = -1;
 300
 301                 if (cmos->day_alrm) {
 302                         if (((unsigned)t->time.tm_mday) <= 0x31)
 303                                 t->time.tm_mday = bcd2bin(t->time.tm_mday);
 304                         else
 305                                 t->time.tm_mday = -1;
 306
 307                         if (cmos->mon_alrm) {
 308                                 if (((unsigned)t->time.tm_mon) <= 0x12)
 309                                         t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
 310                                 else
 311                                         t->time.tm_mon = -1;
 312                         }
 313                 }
 314         }
 315
 316         t->enabled = !!(rtc_control & RTC_AIE);
 317         t->pending = 0;
 318
 319         return 0;
 320 }
 321
 322 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
 323 {
 324         unsigned char   rtc_intr;
 325
 326         /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
 327          * allegedly some older rtcs need that to handle irqs properly
 328          */
 329         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 330
 331         if (use_hpet_alarm())
 332                 return;
 333
 334         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 335         if (is_intr(rtc_intr))
 336                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
 337 }
 338
 339 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
 340 {
 341         unsigned char   rtc_control;
 342
 343         /* flush any pending IRQ status, notably for update irqs,
 344          * before we enable new IRQs
 345          */
 346         rtc_control = CMOS_READ(RTC_CONTROL);
 347         cmos_checkintr(cmos, rtc_control);
 348
 349         rtc_control |= mask;
 350         CMOS_WRITE(rtc_control, RTC_CONTROL);
 351         if (use_hpet_alarm())
 352                 hpet_set_rtc_irq_bit(mask);
 353
 354         if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
 355                 if (cmos->wake_on)
 356                         cmos->wake_on(cmos->dev);
 357         }
 358
 359         cmos_checkintr(cmos, rtc_control);
 360 }
 361
 362 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
 363 {
 364         unsigned char   rtc_control;
 365
 366         rtc_control = CMOS_READ(RTC_CONTROL);
 367         rtc_control &= ~mask;
 368         CMOS_WRITE(rtc_control, RTC_CONTROL);
 369         if (use_hpet_alarm())
 370                 hpet_mask_rtc_irq_bit(mask);
 371
 372         if ((mask & RTC_AIE) && cmos_use_acpi_alarm()) {
 373                 if (cmos->wake_off)
 374                         cmos->wake_off(cmos->dev);
 375         }
 376
 377         cmos_checkintr(cmos, rtc_control);
 378 }
 379
 380 static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t)
 381 {
 382         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 383         struct rtc_time now;
 384
 385         cmos_read_time(dev, &now);
 386
 387         if (!cmos->day_alrm) {
 388                 time64_t t_max_date;
 389                 time64_t t_alrm;
 390
 391                 t_max_date = rtc_tm_to_time64(&now);
 392                 t_max_date += 24 * 60 * 60 - 1;
 393                 t_alrm = rtc_tm_to_time64(&t->time);
 394                 if (t_alrm > t_max_date) {
 395                         dev_err(dev,
 396                                 "Alarms can be up to one day in the future\n");
 397                         return -EINVAL;
 398                 }
 399         } else if (!cmos->mon_alrm) {
 400                 struct rtc_time max_date = now;
 401                 time64_t t_max_date;
 402                 time64_t t_alrm;
 403                 int max_mday;
 404
 405                 if (max_date.tm_mon == 11) {
 406                         max_date.tm_mon = 0;
 407                         max_date.tm_year += 1;
 408                 } else {
 409                         max_date.tm_mon += 1;
 410                 }
 411                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 412                 if (max_date.tm_mday > max_mday)
 413                         max_date.tm_mday = max_mday;
 414
 415                 t_max_date = rtc_tm_to_time64(&max_date);
 416                 t_max_date -= 1;
 417                 t_alrm = rtc_tm_to_time64(&t->time);
 418                 if (t_alrm > t_max_date) {
 419                         dev_err(dev,
 420                                 "Alarms can be up to one month in the future\n");
 421                         return -EINVAL;
 422                 }
 423         } else {
 424                 struct rtc_time max_date = now;
 425                 time64_t t_max_date;
 426                 time64_t t_alrm;
 427                 int max_mday;
 428
 429                 max_date.tm_year += 1;
 430                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 431                 if (max_date.tm_mday > max_mday)
 432                         max_date.tm_mday = max_mday;
 433
 434                 t_max_date = rtc_tm_to_time64(&max_date);
 435                 t_max_date -= 1;
 436                 t_alrm = rtc_tm_to_time64(&t->time);
 437                 if (t_alrm > t_max_date) {
 438                         dev_err(dev,
 439                                 "Alarms can be up to one year in the future\n");
 440                         return -EINVAL;
 441                 }
 442         }
 443
 444         return 0;
 445 }
 446
 447 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 448 {
 449         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 450         unsigned char mon, mday, hrs, min, sec, rtc_control;
 451         int ret;
 452
 453         /* This not only a rtc_op, but also called directly */
 454         if (!is_valid_irq(cmos->irq))
 455                 return -EIO;
 456
 457         ret = cmos_validate_alarm(dev, t);
 458         if (ret < 0)
 459                 return ret;
 460
 461         mon = t->time.tm_mon + 1;
 462         mday = t->time.tm_mday;
 463         hrs = t->time.tm_hour;
 464         min = t->time.tm_min;
 465         sec = t->time.tm_sec;
 466
 467         spin_lock_irq(&rtc_lock);
 468         rtc_control = CMOS_READ(RTC_CONTROL);
 469         spin_unlock_irq(&rtc_lock);
 470
 471         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 472                 /* Writing 0xff means "don't care" or "match all".  */
 473                 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
 474                 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 475                 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
 476                 min = (min < 60) ? bin2bcd(min) : 0xff;
 477                 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
 478         }
 479
 480         spin_lock_irq(&rtc_lock);
 481
 482         /* next rtc irq must not be from previous alarm setting */
 483         cmos_irq_disable(cmos, RTC_AIE);
 484
 485         /* update alarm */
 486         CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 487         CMOS_WRITE(min, RTC_MINUTES_ALARM);
 488         CMOS_WRITE(sec, RTC_SECONDS_ALARM);
 489
 490         /* the system may support an "enhanced" alarm */
 491         if (cmos->day_alrm) {
 492                 CMOS_WRITE(mday, cmos->day_alrm);
 493                 if (cmos->mon_alrm)
 494                         CMOS_WRITE(mon, cmos->mon_alrm);
 495         }
 496
 497         if (use_hpet_alarm()) {
 498                 /*
 499                  * FIXME the HPET alarm glue currently ignores day_alrm
 500                  * and mon_alrm ...
 501                  */
 502                 hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min,
 503                                     t->time.tm_sec);
 504         }
 505
 506         if (t->enabled)
 507                 cmos_irq_enable(cmos, RTC_AIE);
 508
 509         spin_unlock_irq(&rtc_lock);
 510
 511         cmos->alarm_expires = rtc_tm_to_time64(&t->time);
 512
 513         return 0;
 514 }
 515
 516 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 517 {
 518         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 519         unsigned long   flags;
 520
 521         spin_lock_irqsave(&rtc_lock, flags);
 522
 523         if (enabled)
 524                 cmos_irq_enable(cmos, RTC_AIE);
 525         else
 526                 cmos_irq_disable(cmos, RTC_AIE);
 527
 528         spin_unlock_irqrestore(&rtc_lock, flags);
 529         return 0;
 530 }
 531
 532 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 533
 534 static int cmos_procfs(struct device *dev, struct seq_file *seq)
 535 {
 536         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 537         unsigned char   rtc_control, valid;
 538
 539         spin_lock_irq(&rtc_lock);
 540         rtc_control = CMOS_READ(RTC_CONTROL);
 541         valid = CMOS_READ(RTC_VALID);
 542         spin_unlock_irq(&rtc_lock);
 543
 544         /* NOTE:  at least ICH6 reports battery status using a different
 545          * (non-RTC) bit; and SQWE is ignored on many current systems.
 546          */
 547         seq_printf(seq,
 548                    "periodic_IRQ\t: %s\n"
 549                    "update_IRQ\t: %s\n"
 550                    "HPET_emulated\t: %s\n"
 551                    // "square_wave\t: %s\n"
 552                    "BCD\t\t: %s\n"
 553                    "DST_enable\t: %s\n"
 554                    "periodic_freq\t: %d\n"
 555                    "batt_status\t: %s\n",
 556                    (rtc_control & RTC_PIE) ? "yes" : "no",
 557                    (rtc_control & RTC_UIE) ? "yes" : "no",
 558                    use_hpet_alarm() ? "yes" : "no",
 559                    // (rtc_control & RTC_SQWE) ? "yes" : "no",
 560                    (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 561                    (rtc_control & RTC_DST_EN) ? "yes" : "no",
 562                    cmos->rtc->irq_freq,
 563                    (valid & RTC_VRT) ? "okay" : "dead");
 564
 565         return 0;
 566 }
 567
 568 #else
 569 #define cmos_procfs     NULL
 570 #endif
 571
 572 static const struct rtc_class_ops cmos_rtc_ops = {
 573         .read_time              = cmos_read_time,
 574         .set_time               = cmos_set_time,
 575         .read_alarm             = cmos_read_alarm,
 576         .set_alarm              = cmos_set_alarm,
 577         .proc                   = cmos_procfs,
 578         .alarm_irq_enable       = cmos_alarm_irq_enable,
 579 };
 580
 581 /*----------------------------------------------------------------*/
 582
 583 /*
 584  * All these chips have at least 64 bytes of address space, shared by
 585  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 586  * by boot firmware.  Modern chips have 128 or 256 bytes.
 587  */
 588
 589 #define NVRAM_OFFSET    (RTC_REG_D + 1)
 590
 591 static int cmos_nvram_read(void *priv, unsigned int off, void *val,
 592                            size_t count)
 593 {
 594         unsigned char *buf = val;
 595         int     retval;
 596
 597         off += NVRAM_OFFSET;
 598         spin_lock_irq(&rtc_lock);
 599         for (retval = 0; count; count--, off++, retval++) {
 600                 if (off < 128)
 601                         *buf++ = CMOS_READ(off);
 602                 else if (can_bank2)
 603                         *buf++ = cmos_read_bank2(off);
 604                 else
 605                         break;
 606         }
 607         spin_unlock_irq(&rtc_lock);
 608
 609         return retval;
 610 }
 611
 612 static int cmos_nvram_write(void *priv, unsigned int off, void *val,
 613                             size_t count)
 614 {
 615         struct cmos_rtc *cmos = priv;
 616         unsigned char   *buf = val;
 617         int             retval;
 618
 619         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 620          * checksum on part of the NVRAM data.  That's currently ignored
 621          * here.  If userspace is smart enough to know what fields of
 622          * NVRAM to update, updating checksums is also part of its job.
 623          */
 624         off += NVRAM_OFFSET;
 625         spin_lock_irq(&rtc_lock);
 626         for (retval = 0; count; count--, off++, retval++) {
 627                 /* don't trash RTC registers */
 628                 if (off == cmos->day_alrm
 629                                 || off == cmos->mon_alrm
 630                                 || off == cmos->century)
 631                         buf++;
 632                 else if (off < 128)
 633                         CMOS_WRITE(*buf++, off);
 634                 else if (can_bank2)
 635                         cmos_write_bank2(*buf++, off);
 636                 else
 637                         break;
 638         }
 639         spin_unlock_irq(&rtc_lock);
 640
 641         return retval;
 642 }
 643
 644 /*----------------------------------------------------------------*/
 645
 646 static struct cmos_rtc  cmos_rtc;
 647
 648 static irqreturn_t cmos_interrupt(int irq, void *p)
 649 {
 650         u8              irqstat;
 651         u8              rtc_control;
 652
 653         spin_lock(&rtc_lock);
 654
 655         /* When the HPET interrupt handler calls us, the interrupt
 656          * status is passed as arg1 instead of the irq number.  But
 657          * always clear irq status, even when HPET is in the way.
 658          *
 659          * Note that HPET and RTC are almost certainly out of phase,
 660          * giving different IRQ status ...
 661          */
 662         irqstat = CMOS_READ(RTC_INTR_FLAGS);
 663         rtc_control = CMOS_READ(RTC_CONTROL);
 664         if (use_hpet_alarm())
 665                 irqstat = (unsigned long)irq & 0xF0;
 666
 667         /* If we were suspended, RTC_CONTROL may not be accurate since the
 668          * bios may have cleared it.
 669          */
 670         if (!cmos_rtc.suspend_ctrl)
 671                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 672         else
 673                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 674
 675         /* All Linux RTC alarms should be treated as if they were oneshot.
 676          * Similar code may be needed in system wakeup paths, in case the
 677          * alarm woke the system.
 678          */
 679         if (irqstat & RTC_AIE) {
 680                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 681                 rtc_control &= ~RTC_AIE;
 682                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 683                 if (use_hpet_alarm())
 684                         hpet_mask_rtc_irq_bit(RTC_AIE);
 685                 CMOS_READ(RTC_INTR_FLAGS);
 686         }
 687         spin_unlock(&rtc_lock);
 688
 689         if (is_intr(irqstat)) {
 690                 rtc_update_irq(p, 1, irqstat);
 691                 return IRQ_HANDLED;
 692         } else
 693                 return IRQ_NONE;
 694 }
 695
 696 #ifdef  CONFIG_PNP
 697 #define INITSECTION
 698
 699 #else
 700 #define INITSECTION     __init
 701 #endif
 702
 703 static int INITSECTION
 704 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 705 {
 706         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
 707         int                             retval = 0;
 708         unsigned char                   rtc_control;
 709         unsigned                        address_space;
 710         u32                             flags = 0;
 711         struct nvmem_config nvmem_cfg = {
 712                 .name = "cmos_nvram",
 713                 .word_size = 1,
 714                 .stride = 1,
 715                 .reg_read = cmos_nvram_read,
 716                 .reg_write = cmos_nvram_write,
 717                 .priv = &cmos_rtc,
 718         };
 719
 720         /* there can be only one ... */
 721         if (cmos_rtc.dev)
 722                 return -EBUSY;
 723
 724         if (!ports)
 725                 return -ENODEV;
 726
 727         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 728          *
 729          * REVISIT non-x86 systems may instead use memory space resources
 730          * (needing ioremap etc), not i/o space resources like this ...
 731          */
 732         if (RTC_IOMAPPED)
 733                 ports = request_region(ports->start, resource_size(ports),
 734                                        driver_name);
 735         else
 736                 ports = request_mem_region(ports->start, resource_size(ports),
 737                                            driver_name);
 738         if (!ports) {
 739                 dev_dbg(dev, "i/o registers already in use\n");
 740                 return -EBUSY;
 741         }
 742
 743         cmos_rtc.irq = rtc_irq;
 744         cmos_rtc.iomem = ports;
 745
 746         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 747          * driver did, but don't reject unknown configs.   Old hardware
 748          * won't address 128 bytes.  Newer chips have multiple banks,
 749          * though they may not be listed in one I/O resource.
 750          */
 751 #if     defined(CONFIG_ATARI)
 752         address_space = 64;
 753 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 754                         || defined(__sparc__) || defined(__mips__) \
 755                         || defined(__powerpc__)
 756         address_space = 128;
 757 #else
 758 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 759         address_space = 128;
 760 #endif
 761         if (can_bank2 && ports->end > (ports->start + 1))
 762                 address_space = 256;
 763
 764         /* For ACPI systems extension info comes from the FADT.  On others,
 765          * board specific setup provides it as appropriate.  Systems where
 766          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 767          * some almost-clones) can provide hooks to make that behave.
 768          *
 769          * Note that ACPI doesn't preclude putting these registers into
 770          * "extended" areas of the chip, including some that we won't yet
 771          * expect CMOS_READ and friends to handle.
 772          */
 773         if (info) {
 774                 if (info->flags)
 775                         flags = info->flags;
 776                 if (info->address_space)
 777                         address_space = info->address_space;
 778
 779                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
 780                         cmos_rtc.day_alrm = info->rtc_day_alarm;
 781                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
 782                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
 783                 if (info->rtc_century && info->rtc_century < 128)
 784                         cmos_rtc.century = info->rtc_century;
 785
 786                 if (info->wake_on && info->wake_off) {
 787                         cmos_rtc.wake_on = info->wake_on;
 788                         cmos_rtc.wake_off = info->wake_off;
 789                 }
 790         }
 791
 792         cmos_rtc.dev = dev;
 793         dev_set_drvdata(dev, &cmos_rtc);
 794
 795         cmos_rtc.rtc = devm_rtc_allocate_device(dev);
 796         if (IS_ERR(cmos_rtc.rtc)) {
 797                 retval = PTR_ERR(cmos_rtc.rtc);
 798                 goto cleanup0;
 799         }
 800
 801         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 802
 803         spin_lock_irq(&rtc_lock);
 804
 805         /* Ensure that the RTC is accessible. Bit 6 must be 0! */
 806         if ((CMOS_READ(RTC_VALID) & 0x40) != 0) {
 807                 spin_unlock_irq(&rtc_lock);
 808                 dev_warn(dev, "not accessible\n");
 809                 retval = -ENXIO;
 810                 goto cleanup1;
 811         }
 812
 813         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
 814                 /* force periodic irq to CMOS reset default of 1024Hz;
 815                  *
 816                  * REVISIT it's been reported that at least one x86_64 ALI
 817                  * mobo doesn't use 32KHz here ... for portability we might
 818                  * need to do something about other clock frequencies.
 819                  */
 820                 cmos_rtc.rtc->irq_freq = 1024;
 821                 if (use_hpet_alarm())
 822                         hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
 823                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
 824         }
 825
 826         /* disable irqs */
 827         if (is_valid_irq(rtc_irq))
 828                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
 829
 830         rtc_control = CMOS_READ(RTC_CONTROL);
 831
 832         spin_unlock_irq(&rtc_lock);
 833
 834         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
 835                 dev_warn(dev, "only 24-hr supported\n");
 836                 retval = -ENXIO;
 837                 goto cleanup1;
 838         }
 839
 840         if (use_hpet_alarm())
 841                 hpet_rtc_timer_init();
 842
 843         if (is_valid_irq(rtc_irq)) {
 844                 irq_handler_t rtc_cmos_int_handler;
 845
 846                 if (use_hpet_alarm()) {
 847                         rtc_cmos_int_handler = hpet_rtc_interrupt;
 848                         retval = hpet_register_irq_handler(cmos_interrupt);
 849                         if (retval) {
 850                                 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
 851                                 dev_warn(dev, "hpet_register_irq_handler "
 852                                                 " failed in rtc_init().");
 853                                 goto cleanup1;
 854                         }
 855                 } else
 856                         rtc_cmos_int_handler = cmos_interrupt;
 857
 858                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
 859                                 0, dev_name(&cmos_rtc.rtc->dev),
 860                                 cmos_rtc.rtc);
 861                 if (retval < 0) {
 862                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
 863                         goto cleanup1;
 864                 }
 865         } else {
 866                 clear_bit(RTC_FEATURE_ALARM, cmos_rtc.rtc->features);
 867         }
 868
 869         cmos_rtc.rtc->ops = &cmos_rtc_ops;
 870
 871         retval = devm_rtc_register_device(cmos_rtc.rtc);
 872         if (retval)
 873                 goto cleanup2;
 874
 875         /* Set the sync offset for the periodic 11min update correct */
 876         cmos_rtc.rtc->set_offset_nsec = NSEC_PER_SEC / 2;
 877
 878         /* export at least the first block of NVRAM */
 879         nvmem_cfg.size = address_space - NVRAM_OFFSET;
 880         devm_rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg);
 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         memset(&cmos->saved_wkalrm, 0, sizeof(struct rtc_wkalrm));
1016         cmos_read_alarm(dev, &cmos->saved_wkalrm);
1017
1018         dev_dbg(dev, "suspend%s, ctrl %02x\n",
1019                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
1020                         tmp);
1021
1022         return 0;
1023 }
1024
1025 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
1026  * after a detour through G3 "mechanical off", although the ACPI spec
1027  * says wakeup should only work from G1/S4 "hibernate".  To most users,
1028  * distinctions between S4 and S5 are pointless.  So when the hardware
1029  * allows, don't draw that distinction.
1030  */
1031 static inline int cmos_poweroff(struct device *dev)
1032 {
1033         if (!IS_ENABLED(CONFIG_PM))
1034                 return -ENOSYS;
1035
1036         return cmos_suspend(dev);
1037 }
1038
1039 static void cmos_check_wkalrm(struct device *dev)
1040 {
1041         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1042         struct rtc_wkalrm current_alarm;
1043         time64_t t_now;
1044         time64_t t_current_expires;
1045         time64_t t_saved_expires;
1046         struct rtc_time now;
1047
1048         /* Check if we have RTC Alarm armed */
1049         if (!(cmos->suspend_ctrl & RTC_AIE))
1050                 return;
1051
1052         cmos_read_time(dev, &now);
1053         t_now = rtc_tm_to_time64(&now);
1054
1055         /*
1056          * ACPI RTC wake event is cleared after resume from STR,
1057          * ACK the rtc irq here
1058          */
1059         if (t_now >= cmos->alarm_expires && cmos_use_acpi_alarm()) {
1060                 local_irq_disable();
1061                 cmos_interrupt(0, (void *)cmos->rtc);
1062                 local_irq_enable();
1063                 return;
1064         }
1065
1066         memset(&current_alarm, 0, sizeof(struct rtc_wkalrm));
1067         cmos_read_alarm(dev, &current_alarm);
1068         t_current_expires = rtc_tm_to_time64(&current_alarm.time);
1069         t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
1070         if (t_current_expires != t_saved_expires ||
1071             cmos->saved_wkalrm.enabled != current_alarm.enabled) {
1072                 cmos_set_alarm(dev, &cmos->saved_wkalrm);
1073         }
1074 }
1075
1076 static void cmos_check_acpi_rtc_status(struct device *dev,
1077                                        unsigned char *rtc_control);
1078
1079 static int __maybe_unused cmos_resume(struct device *dev)
1080 {
1081         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1082         unsigned char tmp;
1083
1084         if (cmos->enabled_wake && !cmos_use_acpi_alarm()) {
1085                 if (cmos->wake_off)
1086                         cmos->wake_off(dev);
1087                 else
1088                         disable_irq_wake(cmos->irq);
1089                 cmos->enabled_wake = 0;
1090         }
1091
1092         /* The BIOS might have changed the alarm, restore it */
1093         cmos_check_wkalrm(dev);
1094
1095         spin_lock_irq(&rtc_lock);
1096         tmp = cmos->suspend_ctrl;
1097         cmos->suspend_ctrl = 0;
1098         /* re-enable any irqs previously active */
1099         if (tmp & RTC_IRQMASK) {
1100                 unsigned char   mask;
1101
1102                 if (device_may_wakeup(dev) && use_hpet_alarm())
1103                         hpet_rtc_timer_init();
1104
1105                 do {
1106                         CMOS_WRITE(tmp, RTC_CONTROL);
1107                         if (use_hpet_alarm())
1108                                 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1109
1110                         mask = CMOS_READ(RTC_INTR_FLAGS);
1111                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1112                         if (!use_hpet_alarm() || !is_intr(mask))
1113                                 break;
1114
1115                         /* force one-shot behavior if HPET blocked
1116                          * the wake alarm's irq
1117                          */
1118                         rtc_update_irq(cmos->rtc, 1, mask);
1119                         tmp &= ~RTC_AIE;
1120                         hpet_mask_rtc_irq_bit(RTC_AIE);
1121                 } while (mask & RTC_AIE);
1122
1123                 if (tmp & RTC_AIE)
1124                         cmos_check_acpi_rtc_status(dev, &tmp);
1125         }
1126         spin_unlock_irq(&rtc_lock);
1127
1128         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1129
1130         return 0;
1131 }
1132
1133 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1134
1135 /*----------------------------------------------------------------*/
1136
1137 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1138  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1139  * probably list them in similar PNPBIOS tables; so PNP is more common.
1140  *
1141  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1142  * predate even PNPBIOS should set up platform_bus devices.
1143  */
1144
1145 #ifdef  CONFIG_ACPI
1146
1147 #include <linux/acpi.h>
1148
1149 static u32 rtc_handler(void *context)
1150 {
1151         struct device *dev = context;
1152         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1153         unsigned char rtc_control = 0;
1154         unsigned char rtc_intr;
1155         unsigned long flags;
1156
1157
1158         /*
1159          * Always update rtc irq when ACPI is used as RTC Alarm.
1160          * Or else, ACPI SCI is enabled during suspend/resume only,
1161          * update rtc irq in that case.
1162          */
1163         if (cmos_use_acpi_alarm())
1164                 cmos_interrupt(0, (void *)cmos->rtc);
1165         else {
1166                 /* Fix me: can we use cmos_interrupt() here as well? */
1167                 spin_lock_irqsave(&rtc_lock, flags);
1168                 if (cmos_rtc.suspend_ctrl)
1169                         rtc_control = CMOS_READ(RTC_CONTROL);
1170                 if (rtc_control & RTC_AIE) {
1171                         cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1172                         CMOS_WRITE(rtc_control, RTC_CONTROL);
1173                         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1174                         rtc_update_irq(cmos->rtc, 1, rtc_intr);
1175                 }
1176                 spin_unlock_irqrestore(&rtc_lock, flags);
1177         }
1178
1179         pm_wakeup_hard_event(dev);
1180         acpi_clear_event(ACPI_EVENT_RTC);
1181         acpi_disable_event(ACPI_EVENT_RTC, 0);
1182         return ACPI_INTERRUPT_HANDLED;
1183 }
1184
1185 static inline void rtc_wake_setup(struct device *dev)
1186 {
1187         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1188         /*
1189          * After the RTC handler is installed, the Fixed_RTC event should
1190          * be disabled. Only when the RTC alarm is set will it be enabled.
1191          */
1192         acpi_clear_event(ACPI_EVENT_RTC);
1193         acpi_disable_event(ACPI_EVENT_RTC, 0);
1194 }
1195
1196 static void rtc_wake_on(struct device *dev)
1197 {
1198         acpi_clear_event(ACPI_EVENT_RTC);
1199         acpi_enable_event(ACPI_EVENT_RTC, 0);
1200 }
1201
1202 static void rtc_wake_off(struct device *dev)
1203 {
1204         acpi_disable_event(ACPI_EVENT_RTC, 0);
1205 }
1206
1207 #ifdef CONFIG_X86
1208 /* Enable use_acpi_alarm mode for Intel platforms no earlier than 2015 */
1209 static void use_acpi_alarm_quirks(void)
1210 {
1211         if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
1212                 return;
1213
1214         if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
1215                 return;
1216
1217         if (!is_hpet_enabled())
1218                 return;
1219
1220         if (dmi_get_bios_year() < 2015)
1221                 return;
1222
1223         use_acpi_alarm = true;
1224 }
1225 #else
1226 static inline void use_acpi_alarm_quirks(void) { }
1227 #endif
1228
1229 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1230  * its device node and pass extra config data.  This helps its driver use
1231  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1232  * that this board's RTC is wakeup-capable (per ACPI spec).
1233  */
1234 static struct cmos_rtc_board_info acpi_rtc_info;
1235
1236 static void cmos_wake_setup(struct device *dev)
1237 {
1238         if (acpi_disabled)
1239                 return;
1240
1241         use_acpi_alarm_quirks();
1242
1243         rtc_wake_setup(dev);
1244         acpi_rtc_info.wake_on = rtc_wake_on;
1245         acpi_rtc_info.wake_off = rtc_wake_off;
1246
1247         /* workaround bug in some ACPI tables */
1248         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1249                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1250                         acpi_gbl_FADT.month_alarm);
1251                 acpi_gbl_FADT.month_alarm = 0;
1252         }
1253
1254         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1255         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1256         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1257
1258         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1259         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1260                 dev_info(dev, "RTC can wake from S4\n");
1261
1262         dev->platform_data = &acpi_rtc_info;
1263
1264         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1265         device_init_wakeup(dev, 1);
1266 }
1267
1268 static void cmos_check_acpi_rtc_status(struct device *dev,
1269                                        unsigned char *rtc_control)
1270 {
1271         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1272         acpi_event_status rtc_status;
1273         acpi_status status;
1274
1275         if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1276                 return;
1277
1278         status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1279         if (ACPI_FAILURE(status)) {
1280                 dev_err(dev, "Could not get RTC status\n");
1281         } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1282                 unsigned char mask;
1283                 *rtc_control &= ~RTC_AIE;
1284                 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1285                 mask = CMOS_READ(RTC_INTR_FLAGS);
1286                 rtc_update_irq(cmos->rtc, 1, mask);
1287         }
1288 }
1289
1290 #else
1291
1292 static void cmos_wake_setup(struct device *dev)
1293 {
1294 }
1295
1296 static void cmos_check_acpi_rtc_status(struct device *dev,
1297                                        unsigned char *rtc_control)
1298 {
1299 }
1300
1301 #endif
1302
1303 #ifdef  CONFIG_PNP
1304
1305 #include <linux/pnp.h>
1306
1307 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1308 {
1309         cmos_wake_setup(&pnp->dev);
1310
1311         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1312                 unsigned int irq = 0;
1313 #ifdef CONFIG_X86
1314                 /* Some machines contain a PNP entry for the RTC, but
1315                  * don't define the IRQ. It should always be safe to
1316                  * hardcode it on systems with a legacy PIC.
1317                  */
1318                 if (nr_legacy_irqs())
1319                         irq = RTC_IRQ;
1320 #endif
1321                 return cmos_do_probe(&pnp->dev,
1322                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1323         } else {
1324                 return cmos_do_probe(&pnp->dev,
1325                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1326                                 pnp_irq(pnp, 0));
1327         }
1328 }
1329
1330 static void cmos_pnp_remove(struct pnp_dev *pnp)
1331 {
1332         cmos_do_remove(&pnp->dev);
1333 }
1334
1335 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1336 {
1337         struct device *dev = &pnp->dev;
1338         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1339
1340         if (system_state == SYSTEM_POWER_OFF) {
1341                 int retval = cmos_poweroff(dev);
1342
1343                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1344                         return;
1345         }
1346
1347         cmos_do_shutdown(cmos->irq);
1348 }
1349
1350 static const struct pnp_device_id rtc_ids[] = {
1351         { .id = "PNP0b00", },
1352         { .id = "PNP0b01", },
1353         { .id = "PNP0b02", },
1354         { },
1355 };
1356 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1357
1358 static struct pnp_driver cmos_pnp_driver = {
1359         .name           = driver_name,
1360         .id_table       = rtc_ids,
1361         .probe          = cmos_pnp_probe,
1362         .remove         = cmos_pnp_remove,
1363         .shutdown       = cmos_pnp_shutdown,
1364
1365         /* flag ensures resume() gets called, and stops syslog spam */
1366         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1367         .driver         = {
1368                         .pm = &cmos_pm_ops,
1369         },
1370 };
1371
1372 #endif  /* CONFIG_PNP */
1373
1374 #ifdef CONFIG_OF
1375 static const struct of_device_id of_cmos_match[] = {
1376         {
1377                 .compatible = "motorola,mc146818",
1378         },
1379         { },
1380 };
1381 MODULE_DEVICE_TABLE(of, of_cmos_match);
1382
1383 static __init void cmos_of_init(struct platform_device *pdev)
1384 {
1385         struct device_node *node = pdev->dev.of_node;
1386         const __be32 *val;
1387
1388         if (!node)
1389                 return;
1390
1391         val = of_get_property(node, "ctrl-reg", NULL);
1392         if (val)
1393                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1394
1395         val = of_get_property(node, "freq-reg", NULL);
1396         if (val)
1397                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1398 }
1399 #else
1400 static inline void cmos_of_init(struct platform_device *pdev) {}
1401 #endif
1402 /*----------------------------------------------------------------*/
1403
1404 /* Platform setup should have set up an RTC device, when PNP is
1405  * unavailable ... this could happen even on (older) PCs.
1406  */
1407
1408 static int __init cmos_platform_probe(struct platform_device *pdev)
1409 {
1410         struct resource *resource;
1411         int irq;
1412
1413         cmos_of_init(pdev);
1414         cmos_wake_setup(&pdev->dev);
1415
1416         if (RTC_IOMAPPED)
1417                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1418         else
1419                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1420         irq = platform_get_irq(pdev, 0);
1421         if (irq < 0)
1422                 irq = -1;
1423
1424         return cmos_do_probe(&pdev->dev, resource, irq);
1425 }
1426
1427 static int cmos_platform_remove(struct platform_device *pdev)
1428 {
1429         cmos_do_remove(&pdev->dev);
1430         return 0;
1431 }
1432
1433 static void cmos_platform_shutdown(struct platform_device *pdev)
1434 {
1435         struct device *dev = &pdev->dev;
1436         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1437
1438         if (system_state == SYSTEM_POWER_OFF) {
1439                 int retval = cmos_poweroff(dev);
1440
1441                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1442                         return;
1443         }
1444
1445         cmos_do_shutdown(cmos->irq);
1446 }
1447
1448 /* work with hotplug and coldplug */
1449 MODULE_ALIAS("platform:rtc_cmos");
1450
1451 static struct platform_driver cmos_platform_driver = {
1452         .remove         = cmos_platform_remove,
1453         .shutdown       = cmos_platform_shutdown,
1454         .driver = {
1455                 .name           = driver_name,
1456                 .pm             = &cmos_pm_ops,
1457                 .of_match_table = of_match_ptr(of_cmos_match),
1458         }
1459 };
1460
1461 #ifdef CONFIG_PNP
1462 static bool pnp_driver_registered;
1463 #endif
1464 static bool platform_driver_registered;
1465
1466 static int __init cmos_init(void)
1467 {
1468         int retval = 0;
1469
1470 #ifdef  CONFIG_PNP
1471         retval = pnp_register_driver(&cmos_pnp_driver);
1472         if (retval == 0)
1473                 pnp_driver_registered = true;
1474 #endif
1475
1476         if (!cmos_rtc.dev) {
1477                 retval = platform_driver_probe(&cmos_platform_driver,
1478                                                cmos_platform_probe);
1479                 if (retval == 0)
1480                         platform_driver_registered = true;
1481         }
1482
1483         if (retval == 0)
1484                 return 0;
1485
1486 #ifdef  CONFIG_PNP
1487         if (pnp_driver_registered)
1488                 pnp_unregister_driver(&cmos_pnp_driver);
1489 #endif
1490         return retval;
1491 }
1492 module_init(cmos_init);
1493
1494 static void __exit cmos_exit(void)
1495 {
1496 #ifdef  CONFIG_PNP
1497         if (pnp_driver_registered)
1498                 pnp_unregister_driver(&cmos_pnp_driver);
1499 #endif
1500         if (platform_driver_registered)
1501                 platform_driver_unregister(&cmos_platform_driver);
1502 }
1503 module_exit(cmos_exit);
1504
1505
1506 MODULE_AUTHOR("David Brownell");
1507 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1508 MODULE_LICENSE("GPL");