drivers/rtc/rtc-cmos.c

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