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 #include <linux/kernel.h>
  32 #include <linux/module.h>
  33 #include <linux/init.h>
  34 #include <linux/interrupt.h>
  35 #include <linux/spinlock.h>
  36 #include <linux/platform_device.h>
  37 #include <linux/log2.h>
  38 #include <linux/pm.h>
  39 #include <linux/of.h>
  40 #include <linux/of_platform.h>
  41 #include <linux/dmi.h>
  42
  43 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
  44 #include <asm-generic/rtc.h>
  45
  46 struct cmos_rtc {
  47         struct rtc_device       *rtc;
  48         struct device           *dev;
  49         int                     irq;
  50         struct resource         *iomem;
  51
  52         void                    (*wake_on)(struct device *);
  53         void                    (*wake_off)(struct device *);
  54
  55         u8                      enabled_wake;
  56         u8                      suspend_ctrl;
  57
  58         /* newer hardware extends the original register set */
  59         u8                      day_alrm;
  60         u8                      mon_alrm;
  61         u8                      century;
  62 };
  63
  64 /* both platform and pnp busses use negative numbers for invalid irqs */
  65 #define is_valid_irq(n)         ((n) > 0)
  66
  67 static const char driver_name[] = "rtc_cmos";
  68
  69 /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
  70  * always mask it against the irq enable bits in RTC_CONTROL.  Bit values
  71  * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
  72  */
  73 #define RTC_IRQMASK     (RTC_PF | RTC_AF | RTC_UF)
  74
  75 static inline int is_intr(u8 rtc_intr)
  76 {
  77         if (!(rtc_intr & RTC_IRQF))
  78                 return 0;
  79         return rtc_intr & RTC_IRQMASK;
  80 }
  81
  82 /*----------------------------------------------------------------*/
  83
  84 /* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
  85  * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
  86  * used in a broken "legacy replacement" mode.  The breakage includes
  87  * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
  88  * other (better) use.
  89  *
  90  * When that broken mode is in use, platform glue provides a partial
  91  * emulation of hardware RTC IRQ facilities using HPET #1.  We don't
  92  * want to use HPET for anything except those IRQs though...
  93  */
  94 #ifdef CONFIG_HPET_EMULATE_RTC
  95 #include <asm/hpet.h>
  96 #else
  97
  98 static inline int is_hpet_enabled(void)
  99 {
 100         return 0;
 101 }
 102
 103 static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
 104 {
 105         return 0;
 106 }
 107
 108 static inline int hpet_set_rtc_irq_bit(unsigned long mask)
 109 {
 110         return 0;
 111 }
 112
 113 static inline int
 114 hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
 115 {
 116         return 0;
 117 }
 118
 119 static inline int hpet_set_periodic_freq(unsigned long freq)
 120 {
 121         return 0;
 122 }
 123
 124 static inline int hpet_rtc_dropped_irq(void)
 125 {
 126         return 0;
 127 }
 128
 129 static inline int hpet_rtc_timer_init(void)
 130 {
 131         return 0;
 132 }
 133
 134 extern irq_handler_t hpet_rtc_interrupt;
 135
 136 static inline int hpet_register_irq_handler(irq_handler_t handler)
 137 {
 138         return 0;
 139 }
 140
 141 static inline int hpet_unregister_irq_handler(irq_handler_t handler)
 142 {
 143         return 0;
 144 }
 145
 146 #endif
 147
 148 /*----------------------------------------------------------------*/
 149
 150 #ifdef RTC_PORT
 151
 152 /* Most newer x86 systems have two register banks, the first used
 153  * for RTC and NVRAM and the second only for NVRAM.  Caller must
 154  * own rtc_lock ... and we won't worry about access during NMI.
 155  */
 156 #define can_bank2       true
 157
 158 static inline unsigned char cmos_read_bank2(unsigned char addr)
 159 {
 160         outb(addr, RTC_PORT(2));
 161         return inb(RTC_PORT(3));
 162 }
 163
 164 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 165 {
 166         outb(addr, RTC_PORT(2));
 167         outb(val, RTC_PORT(3));
 168 }
 169
 170 #else
 171
 172 #define can_bank2       false
 173
 174 static inline unsigned char cmos_read_bank2(unsigned char addr)
 175 {
 176         return 0;
 177 }
 178
 179 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 180 {
 181 }
 182
 183 #endif
 184
 185 /*----------------------------------------------------------------*/
 186
 187 static int cmos_read_time(struct device *dev, struct rtc_time *t)
 188 {
 189         /* REVISIT:  if the clock has a "century" register, use
 190          * that instead of the heuristic in get_rtc_time().
 191          * That'll make Y3K compatility (year > 2070) easy!
 192          */
 193         get_rtc_time(t);
 194         return 0;
 195 }
 196
 197 static int cmos_set_time(struct device *dev, struct rtc_time *t)
 198 {
 199         /* REVISIT:  set the "century" register if available
 200          *
 201          * NOTE: this ignores the issue whereby updating the seconds
 202          * takes effect exactly 500ms after we write the register.
 203          * (Also queueing and other delays before we get this far.)
 204          */
 205         return set_rtc_time(t);
 206 }
 207
 208 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 209 {
 210         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 211         unsigned char   rtc_control;
 212
 213         if (!is_valid_irq(cmos->irq))
 214                 return -EIO;
 215
 216         /* Basic alarms only support hour, minute, and seconds fields.
 217          * Some also support day and month, for alarms up to a year in
 218          * the future.
 219          */
 220         t->time.tm_mday = -1;
 221         t->time.tm_mon = -1;
 222
 223         spin_lock_irq(&rtc_lock);
 224         t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
 225         t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
 226         t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 227
 228         if (cmos->day_alrm) {
 229                 /* ignore upper bits on readback per ACPI spec */
 230                 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
 231                 if (!t->time.tm_mday)
 232                         t->time.tm_mday = -1;
 233
 234                 if (cmos->mon_alrm) {
 235                         t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
 236                         if (!t->time.tm_mon)
 237                                 t->time.tm_mon = -1;
 238                 }
 239         }
 240
 241         rtc_control = CMOS_READ(RTC_CONTROL);
 242         spin_unlock_irq(&rtc_lock);
 243
 244         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 245                 if (((unsigned)t->time.tm_sec) < 0x60)
 246                         t->time.tm_sec = bcd2bin(t->time.tm_sec);
 247                 else
 248                         t->time.tm_sec = -1;
 249                 if (((unsigned)t->time.tm_min) < 0x60)
 250                         t->time.tm_min = bcd2bin(t->time.tm_min);
 251                 else
 252                         t->time.tm_min = -1;
 253                 if (((unsigned)t->time.tm_hour) < 0x24)
 254                         t->time.tm_hour = bcd2bin(t->time.tm_hour);
 255                 else
 256                         t->time.tm_hour = -1;
 257
 258                 if (cmos->day_alrm) {
 259                         if (((unsigned)t->time.tm_mday) <= 0x31)
 260                                 t->time.tm_mday = bcd2bin(t->time.tm_mday);
 261                         else
 262                                 t->time.tm_mday = -1;
 263
 264                         if (cmos->mon_alrm) {
 265                                 if (((unsigned)t->time.tm_mon) <= 0x12)
 266                                         t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
 267                                 else
 268                                         t->time.tm_mon = -1;
 269                         }
 270                 }
 271         }
 272         t->time.tm_year = -1;
 273
 274         t->enabled = !!(rtc_control & RTC_AIE);
 275         t->pending = 0;
 276
 277         return 0;
 278 }
 279
 280 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
 281 {
 282         unsigned char   rtc_intr;
 283
 284         /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
 285          * allegedly some older rtcs need that to handle irqs properly
 286          */
 287         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 288
 289         if (is_hpet_enabled())
 290                 return;
 291
 292         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 293         if (is_intr(rtc_intr))
 294                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
 295 }
 296
 297 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
 298 {
 299         unsigned char   rtc_control;
 300
 301         /* flush any pending IRQ status, notably for update irqs,
 302          * before we enable new IRQs
 303          */
 304         rtc_control = CMOS_READ(RTC_CONTROL);
 305         cmos_checkintr(cmos, rtc_control);
 306
 307         rtc_control |= mask;
 308         CMOS_WRITE(rtc_control, RTC_CONTROL);
 309         hpet_set_rtc_irq_bit(mask);
 310
 311         cmos_checkintr(cmos, rtc_control);
 312 }
 313
 314 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
 315 {
 316         unsigned char   rtc_control;
 317
 318         rtc_control = CMOS_READ(RTC_CONTROL);
 319         rtc_control &= ~mask;
 320         CMOS_WRITE(rtc_control, RTC_CONTROL);
 321         hpet_mask_rtc_irq_bit(mask);
 322
 323         cmos_checkintr(cmos, rtc_control);
 324 }
 325
 326 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 327 {
 328         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 329         unsigned char mon, mday, hrs, min, sec, rtc_control;
 330
 331         if (!is_valid_irq(cmos->irq))
 332                 return -EIO;
 333
 334         mon = t->time.tm_mon + 1;
 335         mday = t->time.tm_mday;
 336         hrs = t->time.tm_hour;
 337         min = t->time.tm_min;
 338         sec = t->time.tm_sec;
 339
 340         rtc_control = CMOS_READ(RTC_CONTROL);
 341         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 342                 /* Writing 0xff means "don't care" or "match all".  */
 343                 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
 344                 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 345                 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
 346                 min = (min < 60) ? bin2bcd(min) : 0xff;
 347                 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
 348         }
 349
 350         spin_lock_irq(&rtc_lock);
 351
 352         /* next rtc irq must not be from previous alarm setting */
 353         cmos_irq_disable(cmos, RTC_AIE);
 354
 355         /* update alarm */
 356         CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 357         CMOS_WRITE(min, RTC_MINUTES_ALARM);
 358         CMOS_WRITE(sec, RTC_SECONDS_ALARM);
 359
 360         /* the system may support an "enhanced" alarm */
 361         if (cmos->day_alrm) {
 362                 CMOS_WRITE(mday, cmos->day_alrm);
 363                 if (cmos->mon_alrm)
 364                         CMOS_WRITE(mon, cmos->mon_alrm);
 365         }
 366
 367         /* FIXME the HPET alarm glue currently ignores day_alrm
 368          * and mon_alrm ...
 369          */
 370         hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
 371
 372         if (t->enabled)
 373                 cmos_irq_enable(cmos, RTC_AIE);
 374
 375         spin_unlock_irq(&rtc_lock);
 376
 377         return 0;
 378 }
 379
 380 /*
 381  * Do not disable RTC alarm on shutdown - workaround for b0rked BIOSes.
 382  */
 383 static bool alarm_disable_quirk;
 384
 385 static int __init set_alarm_disable_quirk(const struct dmi_system_id *id)
 386 {
 387         alarm_disable_quirk = true;
 388         pr_info("rtc-cmos: BIOS has alarm-disable quirk. ");
 389         pr_info("RTC alarms disabled\n");
 390         return 0;
 391 }
 392
 393 static const struct dmi_system_id rtc_quirks[] __initconst = {
 394         /* https://bugzilla.novell.com/show_bug.cgi?id=805740 */
 395         {
 396                 .callback = set_alarm_disable_quirk,
 397                 .ident    = "IBM Truman",
 398                 .matches  = {
 399                         DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
 400                         DMI_MATCH(DMI_PRODUCT_NAME, "4852570"),
 401                 },
 402         },
 403         /* https://bugzilla.novell.com/show_bug.cgi?id=812592 */
 404         {
 405                 .callback = set_alarm_disable_quirk,
 406                 .ident    = "Gigabyte GA-990XA-UD3",
 407                 .matches  = {
 408                         DMI_MATCH(DMI_SYS_VENDOR,
 409                                         "Gigabyte Technology Co., Ltd."),
 410                         DMI_MATCH(DMI_PRODUCT_NAME, "GA-990XA-UD3"),
 411                 },
 412         },
 413         /* http://permalink.gmane.org/gmane.linux.kernel/1604474 */
 414         {
 415                 .callback = set_alarm_disable_quirk,
 416                 .ident    = "Toshiba Satellite L300",
 417                 .matches  = {
 418                         DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
 419                         DMI_MATCH(DMI_PRODUCT_NAME, "Satellite L300"),
 420                 },
 421         },
 422         {}
 423 };
 424
 425 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 426 {
 427         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 428         unsigned long   flags;
 429
 430         if (!is_valid_irq(cmos->irq))
 431                 return -EINVAL;
 432
 433         if (alarm_disable_quirk)
 434                 return 0;
 435
 436         spin_lock_irqsave(&rtc_lock, flags);
 437
 438         if (enabled)
 439                 cmos_irq_enable(cmos, RTC_AIE);
 440         else
 441                 cmos_irq_disable(cmos, RTC_AIE);
 442
 443         spin_unlock_irqrestore(&rtc_lock, flags);
 444         return 0;
 445 }
 446
 447 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
 448
 449 static int cmos_procfs(struct device *dev, struct seq_file *seq)
 450 {
 451         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 452         unsigned char   rtc_control, valid;
 453
 454         spin_lock_irq(&rtc_lock);
 455         rtc_control = CMOS_READ(RTC_CONTROL);
 456         valid = CMOS_READ(RTC_VALID);
 457         spin_unlock_irq(&rtc_lock);
 458
 459         /* NOTE:  at least ICH6 reports battery status using a different
 460          * (non-RTC) bit; and SQWE is ignored on many current systems.
 461          */
 462         seq_printf(seq,
 463                    "periodic_IRQ\t: %s\n"
 464                    "update_IRQ\t: %s\n"
 465                    "HPET_emulated\t: %s\n"
 466                    // "square_wave\t: %s\n"
 467                    "BCD\t\t: %s\n"
 468                    "DST_enable\t: %s\n"
 469                    "periodic_freq\t: %d\n"
 470                    "batt_status\t: %s\n",
 471                    (rtc_control & RTC_PIE) ? "yes" : "no",
 472                    (rtc_control & RTC_UIE) ? "yes" : "no",
 473                    is_hpet_enabled() ? "yes" : "no",
 474                    // (rtc_control & RTC_SQWE) ? "yes" : "no",
 475                    (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 476                    (rtc_control & RTC_DST_EN) ? "yes" : "no",
 477                    cmos->rtc->irq_freq,
 478                    (valid & RTC_VRT) ? "okay" : "dead");
 479
 480         return 0;
 481 }
 482
 483 #else
 484 #define cmos_procfs     NULL
 485 #endif
 486
 487 static const struct rtc_class_ops cmos_rtc_ops = {
 488         .read_time              = cmos_read_time,
 489         .set_time               = cmos_set_time,
 490         .read_alarm             = cmos_read_alarm,
 491         .set_alarm              = cmos_set_alarm,
 492         .proc                   = cmos_procfs,
 493         .alarm_irq_enable       = cmos_alarm_irq_enable,
 494 };
 495
 496 /*----------------------------------------------------------------*/
 497
 498 /*
 499  * All these chips have at least 64 bytes of address space, shared by
 500  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 501  * by boot firmware.  Modern chips have 128 or 256 bytes.
 502  */
 503
 504 #define NVRAM_OFFSET    (RTC_REG_D + 1)
 505
 506 static ssize_t
 507 cmos_nvram_read(struct file *filp, struct kobject *kobj,
 508                 struct bin_attribute *attr,
 509                 char *buf, loff_t off, size_t count)
 510 {
 511         int     retval;
 512
 513         if (unlikely(off >= attr->size))
 514                 return 0;
 515         if (unlikely(off < 0))
 516                 return -EINVAL;
 517         if ((off + count) > attr->size)
 518                 count = attr->size - off;
 519
 520         off += NVRAM_OFFSET;
 521         spin_lock_irq(&rtc_lock);
 522         for (retval = 0; count; count--, off++, retval++) {
 523                 if (off < 128)
 524                         *buf++ = CMOS_READ(off);
 525                 else if (can_bank2)
 526                         *buf++ = cmos_read_bank2(off);
 527                 else
 528                         break;
 529         }
 530         spin_unlock_irq(&rtc_lock);
 531
 532         return retval;
 533 }
 534
 535 static ssize_t
 536 cmos_nvram_write(struct file *filp, struct kobject *kobj,
 537                 struct bin_attribute *attr,
 538                 char *buf, loff_t off, size_t count)
 539 {
 540         struct cmos_rtc *cmos;
 541         int             retval;
 542
 543         cmos = dev_get_drvdata(container_of(kobj, struct device, kobj));
 544         if (unlikely(off >= attr->size))
 545                 return -EFBIG;
 546         if (unlikely(off < 0))
 547                 return -EINVAL;
 548         if ((off + count) > attr->size)
 549                 count = attr->size - off;
 550
 551         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 552          * checksum on part of the NVRAM data.  That's currently ignored
 553          * here.  If userspace is smart enough to know what fields of
 554          * NVRAM to update, updating checksums is also part of its job.
 555          */
 556         off += NVRAM_OFFSET;
 557         spin_lock_irq(&rtc_lock);
 558         for (retval = 0; count; count--, off++, retval++) {
 559                 /* don't trash RTC registers */
 560                 if (off == cmos->day_alrm
 561                                 || off == cmos->mon_alrm
 562                                 || off == cmos->century)
 563                         buf++;
 564                 else if (off < 128)
 565                         CMOS_WRITE(*buf++, off);
 566                 else if (can_bank2)
 567                         cmos_write_bank2(*buf++, off);
 568                 else
 569                         break;
 570         }
 571         spin_unlock_irq(&rtc_lock);
 572
 573         return retval;
 574 }
 575
 576 static struct bin_attribute nvram = {
 577         .attr = {
 578                 .name   = "nvram",
 579                 .mode   = S_IRUGO | S_IWUSR,
 580         },
 581
 582         .read   = cmos_nvram_read,
 583         .write  = cmos_nvram_write,
 584         /* size gets set up later */
 585 };
 586
 587 /*----------------------------------------------------------------*/
 588
 589 static struct cmos_rtc  cmos_rtc;
 590
 591 static irqreturn_t cmos_interrupt(int irq, void *p)
 592 {
 593         u8              irqstat;
 594         u8              rtc_control;
 595
 596         spin_lock(&rtc_lock);
 597
 598         /* When the HPET interrupt handler calls us, the interrupt
 599          * status is passed as arg1 instead of the irq number.  But
 600          * always clear irq status, even when HPET is in the way.
 601          *
 602          * Note that HPET and RTC are almost certainly out of phase,
 603          * giving different IRQ status ...
 604          */
 605         irqstat = CMOS_READ(RTC_INTR_FLAGS);
 606         rtc_control = CMOS_READ(RTC_CONTROL);
 607         if (is_hpet_enabled())
 608                 irqstat = (unsigned long)irq & 0xF0;
 609
 610         /* If we were suspended, RTC_CONTROL may not be accurate since the
 611          * bios may have cleared it.
 612          */
 613         if (!cmos_rtc.suspend_ctrl)
 614                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 615         else
 616                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 617
 618         /* All Linux RTC alarms should be treated as if they were oneshot.
 619          * Similar code may be needed in system wakeup paths, in case the
 620          * alarm woke the system.
 621          */
 622         if (irqstat & RTC_AIE) {
 623                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 624                 rtc_control &= ~RTC_AIE;
 625                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 626                 hpet_mask_rtc_irq_bit(RTC_AIE);
 627                 CMOS_READ(RTC_INTR_FLAGS);
 628         }
 629         spin_unlock(&rtc_lock);
 630
 631         if (is_intr(irqstat)) {
 632                 rtc_update_irq(p, 1, irqstat);
 633                 return IRQ_HANDLED;
 634         } else
 635                 return IRQ_NONE;
 636 }
 637
 638 #ifdef  CONFIG_PNP
 639 #define INITSECTION
 640
 641 #else
 642 #define INITSECTION     __init
 643 #endif
 644
 645 static int INITSECTION
 646 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 647 {
 648         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
 649         int                             retval = 0;
 650         unsigned char                   rtc_control;
 651         unsigned                        address_space;
 652         u32                             flags = 0;
 653
 654         /* there can be only one ... */
 655         if (cmos_rtc.dev)
 656                 return -EBUSY;
 657
 658         if (!ports)
 659                 return -ENODEV;
 660
 661         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 662          *
 663          * REVISIT non-x86 systems may instead use memory space resources
 664          * (needing ioremap etc), not i/o space resources like this ...
 665          */
 666         if (RTC_IOMAPPED)
 667                 ports = request_region(ports->start, resource_size(ports),
 668                                        driver_name);
 669         else
 670                 ports = request_mem_region(ports->start, resource_size(ports),
 671                                            driver_name);
 672         if (!ports) {
 673                 dev_dbg(dev, "i/o registers already in use\n");
 674                 return -EBUSY;
 675         }
 676
 677         cmos_rtc.irq = rtc_irq;
 678         cmos_rtc.iomem = ports;
 679
 680         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 681          * driver did, but don't reject unknown configs.   Old hardware
 682          * won't address 128 bytes.  Newer chips have multiple banks,
 683          * though they may not be listed in one I/O resource.
 684          */
 685 #if     defined(CONFIG_ATARI)
 686         address_space = 64;
 687 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 688                         || defined(__sparc__) || defined(__mips__) \
 689                         || defined(__powerpc__)
 690         address_space = 128;
 691 #else
 692 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 693         address_space = 128;
 694 #endif
 695         if (can_bank2 && ports->end > (ports->start + 1))
 696                 address_space = 256;
 697
 698         /* For ACPI systems extension info comes from the FADT.  On others,
 699          * board specific setup provides it as appropriate.  Systems where
 700          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 701          * some almost-clones) can provide hooks to make that behave.
 702          *
 703          * Note that ACPI doesn't preclude putting these registers into
 704          * "extended" areas of the chip, including some that we won't yet
 705          * expect CMOS_READ and friends to handle.
 706          */
 707         if (info) {
 708                 if (info->flags)
 709                         flags = info->flags;
 710                 if (info->address_space)
 711                         address_space = info->address_space;
 712
 713                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
 714                         cmos_rtc.day_alrm = info->rtc_day_alarm;
 715                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
 716                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
 717                 if (info->rtc_century && info->rtc_century < 128)
 718                         cmos_rtc.century = info->rtc_century;
 719
 720                 if (info->wake_on && info->wake_off) {
 721                         cmos_rtc.wake_on = info->wake_on;
 722                         cmos_rtc.wake_off = info->wake_off;
 723                 }
 724         }
 725
 726         cmos_rtc.dev = dev;
 727         dev_set_drvdata(dev, &cmos_rtc);
 728
 729         cmos_rtc.rtc = rtc_device_register(driver_name, dev,
 730                                 &cmos_rtc_ops, THIS_MODULE);
 731         if (IS_ERR(cmos_rtc.rtc)) {
 732                 retval = PTR_ERR(cmos_rtc.rtc);
 733                 goto cleanup0;
 734         }
 735
 736         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 737
 738         spin_lock_irq(&rtc_lock);
 739
 740         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
 741                 /* force periodic irq to CMOS reset default of 1024Hz;
 742                  *
 743                  * REVISIT it's been reported that at least one x86_64 ALI
 744                  * mobo doesn't use 32KHz here ... for portability we might
 745                  * need to do something about other clock frequencies.
 746                  */
 747                 cmos_rtc.rtc->irq_freq = 1024;
 748                 hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
 749                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
 750         }
 751
 752         /* disable irqs */
 753         if (is_valid_irq(rtc_irq))
 754                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
 755
 756         rtc_control = CMOS_READ(RTC_CONTROL);
 757
 758         spin_unlock_irq(&rtc_lock);
 759
 760         /* FIXME:
 761          * <asm-generic/rtc.h> doesn't know 12-hour mode either.
 762          */
 763         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
 764                 dev_warn(dev, "only 24-hr supported\n");
 765                 retval = -ENXIO;
 766                 goto cleanup1;
 767         }
 768
 769         if (is_valid_irq(rtc_irq)) {
 770                 irq_handler_t rtc_cmos_int_handler;
 771
 772                 if (is_hpet_enabled()) {
 773                         rtc_cmos_int_handler = hpet_rtc_interrupt;
 774                         retval = hpet_register_irq_handler(cmos_interrupt);
 775                         if (retval) {
 776                                 dev_warn(dev, "hpet_register_irq_handler "
 777                                                 " failed in rtc_init().");
 778                                 goto cleanup1;
 779                         }
 780                 } else
 781                         rtc_cmos_int_handler = cmos_interrupt;
 782
 783                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
 784                                 0, dev_name(&cmos_rtc.rtc->dev),
 785                                 cmos_rtc.rtc);
 786                 if (retval < 0) {
 787                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
 788                         goto cleanup1;
 789                 }
 790         }
 791         hpet_rtc_timer_init();
 792
 793         /* export at least the first block of NVRAM */
 794         nvram.size = address_space - NVRAM_OFFSET;
 795         retval = sysfs_create_bin_file(&dev->kobj, &nvram);
 796         if (retval < 0) {
 797                 dev_dbg(dev, "can't create nvram file? %d\n", retval);
 798                 goto cleanup2;
 799         }
 800
 801         dev_info(dev, "%s%s, %zd bytes nvram%s\n",
 802                 !is_valid_irq(rtc_irq) ? "no alarms" :
 803                         cmos_rtc.mon_alrm ? "alarms up to one year" :
 804                         cmos_rtc.day_alrm ? "alarms up to one month" :
 805                         "alarms up to one day",
 806                 cmos_rtc.century ? ", y3k" : "",
 807                 nvram.size,
 808                 is_hpet_enabled() ? ", hpet irqs" : "");
 809
 810         return 0;
 811
 812 cleanup2:
 813         if (is_valid_irq(rtc_irq))
 814                 free_irq(rtc_irq, cmos_rtc.rtc);
 815 cleanup1:
 816         cmos_rtc.dev = NULL;
 817         rtc_device_unregister(cmos_rtc.rtc);
 818 cleanup0:
 819         if (RTC_IOMAPPED)
 820                 release_region(ports->start, resource_size(ports));
 821         else
 822                 release_mem_region(ports->start, resource_size(ports));
 823         return retval;
 824 }
 825
 826 static void cmos_do_shutdown(int rtc_irq)
 827 {
 828         spin_lock_irq(&rtc_lock);
 829         if (is_valid_irq(rtc_irq))
 830                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
 831         spin_unlock_irq(&rtc_lock);
 832 }
 833
 834 static void __exit cmos_do_remove(struct device *dev)
 835 {
 836         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 837         struct resource *ports;
 838
 839         cmos_do_shutdown(cmos->irq);
 840
 841         sysfs_remove_bin_file(&dev->kobj, &nvram);
 842
 843         if (is_valid_irq(cmos->irq)) {
 844                 free_irq(cmos->irq, cmos->rtc);
 845                 hpet_unregister_irq_handler(cmos_interrupt);
 846         }
 847
 848         rtc_device_unregister(cmos->rtc);
 849         cmos->rtc = NULL;
 850
 851         ports = cmos->iomem;
 852         if (RTC_IOMAPPED)
 853                 release_region(ports->start, resource_size(ports));
 854         else
 855                 release_mem_region(ports->start, resource_size(ports));
 856         cmos->iomem = NULL;
 857
 858         cmos->dev = NULL;
 859 }
 860
 861 #ifdef CONFIG_PM
 862
 863 static int cmos_suspend(struct device *dev)
 864 {
 865         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 866         unsigned char   tmp;
 867
 868         /* only the alarm might be a wakeup event source */
 869         spin_lock_irq(&rtc_lock);
 870         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
 871         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 872                 unsigned char   mask;
 873
 874                 if (device_may_wakeup(dev))
 875                         mask = RTC_IRQMASK & ~RTC_AIE;
 876                 else
 877                         mask = RTC_IRQMASK;
 878                 tmp &= ~mask;
 879                 CMOS_WRITE(tmp, RTC_CONTROL);
 880                 hpet_mask_rtc_irq_bit(mask);
 881
 882                 cmos_checkintr(cmos, tmp);
 883         }
 884         spin_unlock_irq(&rtc_lock);
 885
 886         if (tmp & RTC_AIE) {
 887                 cmos->enabled_wake = 1;
 888                 if (cmos->wake_on)
 889                         cmos->wake_on(dev);
 890                 else
 891                         enable_irq_wake(cmos->irq);
 892         }
 893
 894         dev_dbg(dev, "suspend%s, ctrl %02x\n",
 895                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
 896                         tmp);
 897
 898         return 0;
 899 }
 900
 901 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
 902  * after a detour through G3 "mechanical off", although the ACPI spec
 903  * says wakeup should only work from G1/S4 "hibernate".  To most users,
 904  * distinctions between S4 and S5 are pointless.  So when the hardware
 905  * allows, don't draw that distinction.
 906  */
 907 static inline int cmos_poweroff(struct device *dev)
 908 {
 909         return cmos_suspend(dev);
 910 }
 911
 912 #ifdef  CONFIG_PM_SLEEP
 913
 914 static int cmos_resume(struct device *dev)
 915 {
 916         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 917         unsigned char tmp;
 918
 919         if (cmos->enabled_wake) {
 920                 if (cmos->wake_off)
 921                         cmos->wake_off(dev);
 922                 else
 923                         disable_irq_wake(cmos->irq);
 924                 cmos->enabled_wake = 0;
 925         }
 926
 927         spin_lock_irq(&rtc_lock);
 928         tmp = cmos->suspend_ctrl;
 929         cmos->suspend_ctrl = 0;
 930         /* re-enable any irqs previously active */
 931         if (tmp & RTC_IRQMASK) {
 932                 unsigned char   mask;
 933
 934                 if (device_may_wakeup(dev))
 935                         hpet_rtc_timer_init();
 936
 937                 do {
 938                         CMOS_WRITE(tmp, RTC_CONTROL);
 939                         hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
 940
 941                         mask = CMOS_READ(RTC_INTR_FLAGS);
 942                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
 943                         if (!is_hpet_enabled() || !is_intr(mask))
 944                                 break;
 945
 946                         /* force one-shot behavior if HPET blocked
 947                          * the wake alarm's irq
 948                          */
 949                         rtc_update_irq(cmos->rtc, 1, mask);
 950                         tmp &= ~RTC_AIE;
 951                         hpet_mask_rtc_irq_bit(RTC_AIE);
 952                 } while (mask & RTC_AIE);
 953         }
 954         spin_unlock_irq(&rtc_lock);
 955
 956         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
 957
 958         return 0;
 959 }
 960
 961 #endif
 962 #else
 963
 964 static inline int cmos_poweroff(struct device *dev)
 965 {
 966         return -ENOSYS;
 967 }
 968
 969 #endif
 970
 971 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
 972
 973 /*----------------------------------------------------------------*/
 974
 975 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
 976  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
 977  * probably list them in similar PNPBIOS tables; so PNP is more common.
 978  *
 979  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
 980  * predate even PNPBIOS should set up platform_bus devices.
 981  */
 982
 983 #ifdef  CONFIG_ACPI
 984
 985 #include <linux/acpi.h>
 986
 987 static u32 rtc_handler(void *context)
 988 {
 989         struct device *dev = context;
 990
 991         pm_wakeup_event(dev, 0);
 992         acpi_clear_event(ACPI_EVENT_RTC);
 993         acpi_disable_event(ACPI_EVENT_RTC, 0);
 994         return ACPI_INTERRUPT_HANDLED;
 995 }
 996
 997 static inline void rtc_wake_setup(struct device *dev)
 998 {
 999         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1000         /*
1001          * After the RTC handler is installed, the Fixed_RTC event should
1002          * be disabled. Only when the RTC alarm is set will it be enabled.
1003          */
1004         acpi_clear_event(ACPI_EVENT_RTC);
1005         acpi_disable_event(ACPI_EVENT_RTC, 0);
1006 }
1007
1008 static void rtc_wake_on(struct device *dev)
1009 {
1010         acpi_clear_event(ACPI_EVENT_RTC);
1011         acpi_enable_event(ACPI_EVENT_RTC, 0);
1012 }
1013
1014 static void rtc_wake_off(struct device *dev)
1015 {
1016         acpi_disable_event(ACPI_EVENT_RTC, 0);
1017 }
1018
1019 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1020  * its device node and pass extra config data.  This helps its driver use
1021  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1022  * that this board's RTC is wakeup-capable (per ACPI spec).
1023  */
1024 static struct cmos_rtc_board_info acpi_rtc_info;
1025
1026 static void cmos_wake_setup(struct device *dev)
1027 {
1028         if (acpi_disabled)
1029                 return;
1030
1031         rtc_wake_setup(dev);
1032         acpi_rtc_info.wake_on = rtc_wake_on;
1033         acpi_rtc_info.wake_off = rtc_wake_off;
1034
1035         /* workaround bug in some ACPI tables */
1036         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1037                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1038                         acpi_gbl_FADT.month_alarm);
1039                 acpi_gbl_FADT.month_alarm = 0;
1040         }
1041
1042         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1043         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1044         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1045
1046         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1047         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1048                 dev_info(dev, "RTC can wake from S4\n");
1049
1050         dev->platform_data = &acpi_rtc_info;
1051
1052         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1053         device_init_wakeup(dev, 1);
1054 }
1055
1056 #else
1057
1058 static void cmos_wake_setup(struct device *dev)
1059 {
1060 }
1061
1062 #endif
1063
1064 #ifdef  CONFIG_PNP
1065
1066 #include <linux/pnp.h>
1067
1068 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1069 {
1070         cmos_wake_setup(&pnp->dev);
1071
1072         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0))
1073                 /* Some machines contain a PNP entry for the RTC, but
1074                  * don't define the IRQ. It should always be safe to
1075                  * hardcode it in these cases
1076                  */
1077                 return cmos_do_probe(&pnp->dev,
1078                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), 8);
1079         else
1080                 return cmos_do_probe(&pnp->dev,
1081                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1082                                 pnp_irq(pnp, 0));
1083 }
1084
1085 static void __exit cmos_pnp_remove(struct pnp_dev *pnp)
1086 {
1087         cmos_do_remove(&pnp->dev);
1088 }
1089
1090 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1091 {
1092         struct device *dev = &pnp->dev;
1093         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1094
1095         if (system_state == SYSTEM_POWER_OFF && !cmos_poweroff(dev))
1096                 return;
1097
1098         cmos_do_shutdown(cmos->irq);
1099 }
1100
1101 static const struct pnp_device_id rtc_ids[] = {
1102         { .id = "PNP0b00", },
1103         { .id = "PNP0b01", },
1104         { .id = "PNP0b02", },
1105         { },
1106 };
1107 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1108
1109 static struct pnp_driver cmos_pnp_driver = {
1110         .name           = (char *) driver_name,
1111         .id_table       = rtc_ids,
1112         .probe          = cmos_pnp_probe,
1113         .remove         = __exit_p(cmos_pnp_remove),
1114         .shutdown       = cmos_pnp_shutdown,
1115
1116         /* flag ensures resume() gets called, and stops syslog spam */
1117         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1118         .driver         = {
1119                         .pm = &cmos_pm_ops,
1120         },
1121 };
1122
1123 #endif  /* CONFIG_PNP */
1124
1125 #ifdef CONFIG_OF
1126 static const struct of_device_id of_cmos_match[] = {
1127         {
1128                 .compatible = "motorola,mc146818",
1129         },
1130         { },
1131 };
1132 MODULE_DEVICE_TABLE(of, of_cmos_match);
1133
1134 static __init void cmos_of_init(struct platform_device *pdev)
1135 {
1136         struct device_node *node = pdev->dev.of_node;
1137         struct rtc_time time;
1138         int ret;
1139         const __be32 *val;
1140
1141         if (!node)
1142                 return;
1143
1144         val = of_get_property(node, "ctrl-reg", NULL);
1145         if (val)
1146                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1147
1148         val = of_get_property(node, "freq-reg", NULL);
1149         if (val)
1150                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1151
1152         get_rtc_time(&time);
1153         ret = rtc_valid_tm(&time);
1154         if (ret) {
1155                 struct rtc_time def_time = {
1156                         .tm_year = 1,
1157                         .tm_mday = 1,
1158                 };
1159                 set_rtc_time(&def_time);
1160         }
1161 }
1162 #else
1163 static inline void cmos_of_init(struct platform_device *pdev) {}
1164 #endif
1165 /*----------------------------------------------------------------*/
1166
1167 /* Platform setup should have set up an RTC device, when PNP is
1168  * unavailable ... this could happen even on (older) PCs.
1169  */
1170
1171 static int __init cmos_platform_probe(struct platform_device *pdev)
1172 {
1173         struct resource *resource;
1174         int irq;
1175
1176         cmos_of_init(pdev);
1177         cmos_wake_setup(&pdev->dev);
1178
1179         if (RTC_IOMAPPED)
1180                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1181         else
1182                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1183         irq = platform_get_irq(pdev, 0);
1184         if (irq < 0)
1185                 irq = -1;
1186
1187         return cmos_do_probe(&pdev->dev, resource, irq);
1188 }
1189
1190 static int __exit cmos_platform_remove(struct platform_device *pdev)
1191 {
1192         cmos_do_remove(&pdev->dev);
1193         return 0;
1194 }
1195
1196 static void cmos_platform_shutdown(struct platform_device *pdev)
1197 {
1198         struct device *dev = &pdev->dev;
1199         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1200
1201         if (system_state == SYSTEM_POWER_OFF && !cmos_poweroff(dev))
1202                 return;
1203
1204         cmos_do_shutdown(cmos->irq);
1205 }
1206
1207 /* work with hotplug and coldplug */
1208 MODULE_ALIAS("platform:rtc_cmos");
1209
1210 static struct platform_driver cmos_platform_driver = {
1211         .remove         = __exit_p(cmos_platform_remove),
1212         .shutdown       = cmos_platform_shutdown,
1213         .driver = {
1214                 .name           = driver_name,
1215 #ifdef CONFIG_PM
1216                 .pm             = &cmos_pm_ops,
1217 #endif
1218                 .of_match_table = of_match_ptr(of_cmos_match),
1219         }
1220 };
1221
1222 #ifdef CONFIG_PNP
1223 static bool pnp_driver_registered;
1224 #endif
1225 static bool platform_driver_registered;
1226
1227 static int __init cmos_init(void)
1228 {
1229         int retval = 0;
1230
1231 #ifdef  CONFIG_PNP
1232         retval = pnp_register_driver(&cmos_pnp_driver);
1233         if (retval == 0)
1234                 pnp_driver_registered = true;
1235 #endif
1236
1237         if (!cmos_rtc.dev) {
1238                 retval = platform_driver_probe(&cmos_platform_driver,
1239                                                cmos_platform_probe);
1240                 if (retval == 0)
1241                         platform_driver_registered = true;
1242         }
1243
1244         dmi_check_system(rtc_quirks);
1245
1246         if (retval == 0)
1247                 return 0;
1248
1249 #ifdef  CONFIG_PNP
1250         if (pnp_driver_registered)
1251                 pnp_unregister_driver(&cmos_pnp_driver);
1252 #endif
1253         return retval;
1254 }
1255 module_init(cmos_init);
1256
1257 static void __exit cmos_exit(void)
1258 {
1259 #ifdef  CONFIG_PNP
1260         if (pnp_driver_registered)
1261                 pnp_unregister_driver(&cmos_pnp_driver);
1262 #endif
1263         if (platform_driver_registered)
1264                 platform_driver_unregister(&cmos_platform_driver);
1265 }
1266 module_exit(cmos_exit);
1267
1268
1269 MODULE_AUTHOR("David Brownell");
1270 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1271 MODULE_LICENSE("GPL");