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/mod_devicetable.h>
  38
  39 #ifdef CONFIG_HPET_EMULATE_RTC
  40 #include <asm/hpet.h>
  41 #endif
  42
  43 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
  44 #include <asm-generic/rtc.h>
  45
  46 #ifndef CONFIG_HPET_EMULATE_RTC
  47 #define is_hpet_enabled()                       0
  48 #define hpet_set_alarm_time(hrs, min, sec)      do { } while (0)
  49 #define hpet_set_periodic_freq(arg)             0
  50 #define hpet_mask_rtc_irq_bit(arg)              do { } while (0)
  51 #define hpet_set_rtc_irq_bit(arg)               do { } while (0)
  52 #define hpet_rtc_timer_init()                   do { } while (0)
  53 #define hpet_register_irq_handler(h)            0
  54 #define hpet_unregister_irq_handler(h)          do { } while (0)
  55 extern irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id);
  56 #endif
  57
  58 struct cmos_rtc {
  59         struct rtc_device       *rtc;
  60         struct device           *dev;
  61         int                     irq;
  62         struct resource         *iomem;
  63
  64         void                    (*wake_on)(struct device *);
  65         void                    (*wake_off)(struct device *);
  66
  67         u8                      enabled_wake;
  68         u8                      suspend_ctrl;
  69
  70         /* newer hardware extends the original register set */
  71         u8                      day_alrm;
  72         u8                      mon_alrm;
  73         u8                      century;
  74 };
  75
  76 /* both platform and pnp busses use negative numbers for invalid irqs */
  77 #define is_valid_irq(n)         ((n) >= 0)
  78
  79 static const char driver_name[] = "rtc_cmos";
  80
  81 /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
  82  * always mask it against the irq enable bits in RTC_CONTROL.  Bit values
  83  * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
  84  */
  85 #define RTC_IRQMASK     (RTC_PF | RTC_AF | RTC_UF)
  86
  87 static inline int is_intr(u8 rtc_intr)
  88 {
  89         if (!(rtc_intr & RTC_IRQF))
  90                 return 0;
  91         return rtc_intr & RTC_IRQMASK;
  92 }
  93
  94 /*----------------------------------------------------------------*/
  95
  96 static int cmos_read_time(struct device *dev, struct rtc_time *t)
  97 {
  98         /* REVISIT:  if the clock has a "century" register, use
  99          * that instead of the heuristic in get_rtc_time().
 100          * That'll make Y3K compatility (year > 2070) easy!
 101          */
 102         get_rtc_time(t);
 103         return 0;
 104 }
 105
 106 static int cmos_set_time(struct device *dev, struct rtc_time *t)
 107 {
 108         /* REVISIT:  set the "century" register if available
 109          *
 110          * NOTE: this ignores the issue whereby updating the seconds
 111          * takes effect exactly 500ms after we write the register.
 112          * (Also queueing and other delays before we get this far.)
 113          */
 114         return set_rtc_time(t);
 115 }
 116
 117 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 118 {
 119         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 120         unsigned char   rtc_control;
 121
 122         if (!is_valid_irq(cmos->irq))
 123                 return -EIO;
 124
 125         /* Basic alarms only support hour, minute, and seconds fields.
 126          * Some also support day and month, for alarms up to a year in
 127          * the future.
 128          */
 129         t->time.tm_mday = -1;
 130         t->time.tm_mon = -1;
 131
 132         spin_lock_irq(&rtc_lock);
 133         t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
 134         t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
 135         t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 136
 137         if (cmos->day_alrm) {
 138                 /* ignore upper bits on readback per ACPI spec */
 139                 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
 140                 if (!t->time.tm_mday)
 141                         t->time.tm_mday = -1;
 142
 143                 if (cmos->mon_alrm) {
 144                         t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
 145                         if (!t->time.tm_mon)
 146                                 t->time.tm_mon = -1;
 147                 }
 148         }
 149
 150         rtc_control = CMOS_READ(RTC_CONTROL);
 151         spin_unlock_irq(&rtc_lock);
 152
 153         /* REVISIT this assumes PC style usage:  always BCD */
 154
 155         if (((unsigned)t->time.tm_sec) < 0x60)
 156                 t->time.tm_sec = BCD2BIN(t->time.tm_sec);
 157         else
 158                 t->time.tm_sec = -1;
 159         if (((unsigned)t->time.tm_min) < 0x60)
 160                 t->time.tm_min = BCD2BIN(t->time.tm_min);
 161         else
 162                 t->time.tm_min = -1;
 163         if (((unsigned)t->time.tm_hour) < 0x24)
 164                 t->time.tm_hour = BCD2BIN(t->time.tm_hour);
 165         else
 166                 t->time.tm_hour = -1;
 167
 168         if (cmos->day_alrm) {
 169                 if (((unsigned)t->time.tm_mday) <= 0x31)
 170                         t->time.tm_mday = BCD2BIN(t->time.tm_mday);
 171                 else
 172                         t->time.tm_mday = -1;
 173                 if (cmos->mon_alrm) {
 174                         if (((unsigned)t->time.tm_mon) <= 0x12)
 175                                 t->time.tm_mon = BCD2BIN(t->time.tm_mon) - 1;
 176                         else
 177                                 t->time.tm_mon = -1;
 178                 }
 179         }
 180         t->time.tm_year = -1;
 181
 182         t->enabled = !!(rtc_control & RTC_AIE);
 183         t->pending = 0;
 184
 185         return 0;
 186 }
 187
 188 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 189 {
 190         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 191         unsigned char   mon, mday, hrs, min, sec;
 192         unsigned char   rtc_control, rtc_intr;
 193
 194         if (!is_valid_irq(cmos->irq))
 195                 return -EIO;
 196
 197         /* REVISIT this assumes PC style usage:  always BCD */
 198
 199         /* Writing 0xff means "don't care" or "match all".  */
 200
 201         mon = t->time.tm_mon;
 202         mon = (mon < 12) ? BIN2BCD(mon) : 0xff;
 203         mon++;
 204
 205         mday = t->time.tm_mday;
 206         mday = (mday >= 1 && mday <= 31) ? BIN2BCD(mday) : 0xff;
 207
 208         hrs = t->time.tm_hour;
 209         hrs = (hrs < 24) ? BIN2BCD(hrs) : 0xff;
 210
 211         min = t->time.tm_min;
 212         min = (min < 60) ? BIN2BCD(min) : 0xff;
 213
 214         sec = t->time.tm_sec;
 215         sec = (sec < 60) ? BIN2BCD(sec) : 0xff;
 216
 217         hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
 218         spin_lock_irq(&rtc_lock);
 219
 220         /* next rtc irq must not be from previous alarm setting */
 221         rtc_control = CMOS_READ(RTC_CONTROL);
 222         rtc_control &= ~RTC_AIE;
 223         CMOS_WRITE(rtc_control, RTC_CONTROL);
 224         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 225         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 226         if (is_intr(rtc_intr))
 227                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
 228
 229         /* update alarm */
 230         CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 231         CMOS_WRITE(min, RTC_MINUTES_ALARM);
 232         CMOS_WRITE(sec, RTC_SECONDS_ALARM);
 233
 234         /* the system may support an "enhanced" alarm */
 235         if (cmos->day_alrm) {
 236                 CMOS_WRITE(mday, cmos->day_alrm);
 237                 if (cmos->mon_alrm)
 238                         CMOS_WRITE(mon, cmos->mon_alrm);
 239         }
 240
 241         if (t->enabled) {
 242                 rtc_control |= RTC_AIE;
 243                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 244                 rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 245                 rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 246                 if (is_intr(rtc_intr))
 247                         rtc_update_irq(cmos->rtc, 1, rtc_intr);
 248         }
 249
 250         spin_unlock_irq(&rtc_lock);
 251
 252         return 0;
 253 }
 254
 255 static int cmos_irq_set_freq(struct device *dev, int freq)
 256 {
 257         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 258         int             f;
 259         unsigned long   flags;
 260
 261         if (!is_valid_irq(cmos->irq))
 262                 return -ENXIO;
 263
 264         /* 0 = no irqs; 1 = 2^15 Hz ... 15 = 2^0 Hz */
 265         f = ffs(freq);
 266         if (f-- > 16)
 267                 return -EINVAL;
 268         f = 16 - f;
 269
 270         spin_lock_irqsave(&rtc_lock, flags);
 271         if (!hpet_set_periodic_freq(freq))
 272                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | f, RTC_FREQ_SELECT);
 273         spin_unlock_irqrestore(&rtc_lock, flags);
 274
 275         return 0;
 276 }
 277
 278 static int cmos_irq_set_state(struct device *dev, int enabled)
 279 {
 280         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 281         unsigned char   rtc_control, rtc_intr;
 282         unsigned long   flags;
 283
 284         if (!is_valid_irq(cmos->irq))
 285                 return -ENXIO;
 286
 287         spin_lock_irqsave(&rtc_lock, flags);
 288         rtc_control = CMOS_READ(RTC_CONTROL);
 289
 290         if (enabled)
 291                 rtc_control |= RTC_PIE;
 292         else
 293                 rtc_control &= ~RTC_PIE;
 294
 295         CMOS_WRITE(rtc_control, RTC_CONTROL);
 296
 297         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 298         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 299         if (is_intr(rtc_intr))
 300                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
 301
 302         spin_unlock_irqrestore(&rtc_lock, flags);
 303         return 0;
 304 }
 305
 306 #if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)
 307
 308 static int
 309 cmos_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 310 {
 311         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 312         unsigned char   rtc_control, rtc_intr;
 313         unsigned long   flags;
 314
 315         switch (cmd) {
 316         case RTC_AIE_OFF:
 317         case RTC_AIE_ON:
 318         case RTC_UIE_OFF:
 319         case RTC_UIE_ON:
 320         case RTC_PIE_OFF:
 321         case RTC_PIE_ON:
 322                 if (!is_valid_irq(cmos->irq))
 323                         return -EINVAL;
 324                 break;
 325         default:
 326                 return -ENOIOCTLCMD;
 327         }
 328
 329         spin_lock_irqsave(&rtc_lock, flags);
 330         rtc_control = CMOS_READ(RTC_CONTROL);
 331         switch (cmd) {
 332         case RTC_AIE_OFF:       /* alarm off */
 333                 rtc_control &= ~RTC_AIE;
 334                 hpet_mask_rtc_irq_bit(RTC_AIE);
 335                 break;
 336         case RTC_AIE_ON:        /* alarm on */
 337                 rtc_control |= RTC_AIE;
 338                 hpet_set_rtc_irq_bit(RTC_AIE);
 339                 break;
 340         case RTC_UIE_OFF:       /* update off */
 341                 rtc_control &= ~RTC_UIE;
 342                 hpet_mask_rtc_irq_bit(RTC_UIE);
 343                 break;
 344         case RTC_UIE_ON:        /* update on */
 345                 rtc_control |= RTC_UIE;
 346                 hpet_set_rtc_irq_bit(RTC_UIE);
 347                 break;
 348         case RTC_PIE_OFF:       /* periodic off */
 349                 rtc_control &= ~RTC_PIE;
 350                 hpet_mask_rtc_irq_bit(RTC_PIE);
 351                 break;
 352         case RTC_PIE_ON:        /* periodic on */
 353                 rtc_control |= RTC_PIE;
 354                 hpet_set_rtc_irq_bit(RTC_PIE);
 355                 break;
 356         }
 357         if (!is_hpet_enabled())
 358                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 359
 360         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 361         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 362         if (is_intr(rtc_intr))
 363                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
 364
 365         spin_unlock_irqrestore(&rtc_lock, flags);
 366         return 0;
 367 }
 368
 369 #else
 370 #define cmos_rtc_ioctl  NULL
 371 #endif
 372
 373 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
 374
 375 static int cmos_procfs(struct device *dev, struct seq_file *seq)
 376 {
 377         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 378         unsigned char   rtc_control, valid;
 379
 380         spin_lock_irq(&rtc_lock);
 381         rtc_control = CMOS_READ(RTC_CONTROL);
 382         valid = CMOS_READ(RTC_VALID);
 383         spin_unlock_irq(&rtc_lock);
 384
 385         /* NOTE:  at least ICH6 reports battery status using a different
 386          * (non-RTC) bit; and SQWE is ignored on many current systems.
 387          */
 388         return seq_printf(seq,
 389                         "periodic_IRQ\t: %s\n"
 390                         "update_IRQ\t: %s\n"
 391 <<<<<<< HEAD:drivers/rtc/rtc-cmos.c
 392 =======
 393                         "HPET_emulated\t: %s\n"
 394 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/rtc/rtc-cmos.c
 395                         // "square_wave\t: %s\n"
 396                         // "BCD\t\t: %s\n"
 397                         "DST_enable\t: %s\n"
 398                         "periodic_freq\t: %d\n"
 399                         "batt_status\t: %s\n",
 400                         (rtc_control & RTC_PIE) ? "yes" : "no",
 401                         (rtc_control & RTC_UIE) ? "yes" : "no",
 402 <<<<<<< HEAD:drivers/rtc/rtc-cmos.c
 403 =======
 404                         is_hpet_enabled() ? "yes" : "no",
 405 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/rtc/rtc-cmos.c
 406                         // (rtc_control & RTC_SQWE) ? "yes" : "no",
 407                         // (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 408                         (rtc_control & RTC_DST_EN) ? "yes" : "no",
 409                         cmos->rtc->irq_freq,
 410                         (valid & RTC_VRT) ? "okay" : "dead");
 411 }
 412
 413 #else
 414 #define cmos_procfs     NULL
 415 #endif
 416
 417 static const struct rtc_class_ops cmos_rtc_ops = {
 418         .ioctl          = cmos_rtc_ioctl,
 419         .read_time      = cmos_read_time,
 420         .set_time       = cmos_set_time,
 421         .read_alarm     = cmos_read_alarm,
 422         .set_alarm      = cmos_set_alarm,
 423         .proc           = cmos_procfs,
 424         .irq_set_freq   = cmos_irq_set_freq,
 425         .irq_set_state  = cmos_irq_set_state,
 426 };
 427
 428 /*----------------------------------------------------------------*/
 429
 430 /*
 431  * All these chips have at least 64 bytes of address space, shared by
 432  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 433  * by boot firmware.  Modern chips have 128 or 256 bytes.
 434  */
 435
 436 #define NVRAM_OFFSET    (RTC_REG_D + 1)
 437
 438 static ssize_t
 439 cmos_nvram_read(struct kobject *kobj, struct bin_attribute *attr,
 440                 char *buf, loff_t off, size_t count)
 441 {
 442         int     retval;
 443
 444         if (unlikely(off >= attr->size))
 445                 return 0;
 446         if ((off + count) > attr->size)
 447                 count = attr->size - off;
 448
 449         spin_lock_irq(&rtc_lock);
 450         for (retval = 0, off += NVRAM_OFFSET; count--; retval++, off++)
 451                 *buf++ = CMOS_READ(off);
 452         spin_unlock_irq(&rtc_lock);
 453
 454         return retval;
 455 }
 456
 457 static ssize_t
 458 cmos_nvram_write(struct kobject *kobj, struct bin_attribute *attr,
 459                 char *buf, loff_t off, size_t count)
 460 {
 461         struct cmos_rtc *cmos;
 462         int             retval;
 463
 464         cmos = dev_get_drvdata(container_of(kobj, struct device, kobj));
 465         if (unlikely(off >= attr->size))
 466                 return -EFBIG;
 467         if ((off + count) > attr->size)
 468                 count = attr->size - off;
 469
 470         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 471          * checksum on part of the NVRAM data.  That's currently ignored
 472          * here.  If userspace is smart enough to know what fields of
 473          * NVRAM to update, updating checksums is also part of its job.
 474          */
 475         spin_lock_irq(&rtc_lock);
 476         for (retval = 0, off += NVRAM_OFFSET; count--; retval++, off++) {
 477                 /* don't trash RTC registers */
 478                 if (off == cmos->day_alrm
 479                                 || off == cmos->mon_alrm
 480                                 || off == cmos->century)
 481                         buf++;
 482                 else
 483                         CMOS_WRITE(*buf++, off);
 484         }
 485         spin_unlock_irq(&rtc_lock);
 486
 487         return retval;
 488 }
 489
 490 static struct bin_attribute nvram = {
 491         .attr = {
 492                 .name   = "nvram",
 493                 .mode   = S_IRUGO | S_IWUSR,
 494                 .owner  = THIS_MODULE,
 495         },
 496
 497         .read   = cmos_nvram_read,
 498         .write  = cmos_nvram_write,
 499         /* size gets set up later */
 500 };
 501
 502 /*----------------------------------------------------------------*/
 503
 504 static struct cmos_rtc  cmos_rtc;
 505
 506 static irqreturn_t cmos_interrupt(int irq, void *p)
 507 {
 508         u8              irqstat;
 509         u8              rtc_control;
 510
 511         spin_lock(&rtc_lock);
 512         /*
 513          * In this case it is HPET RTC interrupt handler
 514          * calling us, with the interrupt information
 515          * passed as arg1, instead of irq.
 516          */
 517         if (is_hpet_enabled())
 518                 irqstat = (unsigned long)irq & 0xF0;
 519         else {
 520                 irqstat = CMOS_READ(RTC_INTR_FLAGS);
 521                 rtc_control = CMOS_READ(RTC_CONTROL);
 522                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 523         }
 524
 525         /* All Linux RTC alarms should be treated as if they were oneshot.
 526          * Similar code may be needed in system wakeup paths, in case the
 527          * alarm woke the system.
 528          */
 529         if (irqstat & RTC_AIE) {
 530                 rtc_control = CMOS_READ(RTC_CONTROL);
 531                 rtc_control &= ~RTC_AIE;
 532                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 533                 CMOS_READ(RTC_INTR_FLAGS);
 534         }
 535         spin_unlock(&rtc_lock);
 536
 537         if (is_intr(irqstat)) {
 538                 rtc_update_irq(p, 1, irqstat);
 539                 return IRQ_HANDLED;
 540         } else
 541                 return IRQ_NONE;
 542 }
 543
 544 #ifdef  CONFIG_PNP
 545 #define INITSECTION
 546
 547 #else
 548 #define INITSECTION     __init
 549 #endif
 550
 551 static int INITSECTION
 552 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 553 {
 554         struct cmos_rtc_board_info      *info = dev->platform_data;
 555         int                             retval = 0;
 556         unsigned char                   rtc_control;
 557         unsigned                        address_space;
 558
 559         /* there can be only one ... */
 560         if (cmos_rtc.dev)
 561                 return -EBUSY;
 562
 563         if (!ports)
 564                 return -ENODEV;
 565
 566         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 567          *
 568          * REVISIT non-x86 systems may instead use memory space resources
 569          * (needing ioremap etc), not i/o space resources like this ...
 570          */
 571         ports = request_region(ports->start,
 572                         ports->end + 1 - ports->start,
 573                         driver_name);
 574         if (!ports) {
 575                 dev_dbg(dev, "i/o registers already in use\n");
 576                 return -EBUSY;
 577         }
 578
 579         cmos_rtc.irq = rtc_irq;
 580         cmos_rtc.iomem = ports;
 581
 582         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 583          * driver did, but don't reject unknown configs.   Old hardware
 584          * won't address 128 bytes, and for now we ignore the way newer
 585          * chips can address 256 bytes (using two more i/o ports).
 586          */
 587 #if     defined(CONFIG_ATARI)
 588         address_space = 64;
 589 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__)
 590         address_space = 128;
 591 #else
 592 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 593         address_space = 128;
 594 #endif
 595
 596         /* For ACPI systems extension info comes from the FADT.  On others,
 597          * board specific setup provides it as appropriate.  Systems where
 598          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 599          * some almost-clones) can provide hooks to make that behave.
 600          *
 601          * Note that ACPI doesn't preclude putting these registers into
 602          * "extended" areas of the chip, including some that we won't yet
 603          * expect CMOS_READ and friends to handle.
 604          */
 605         if (info) {
 606                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
 607                         cmos_rtc.day_alrm = info->rtc_day_alarm;
 608                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
 609                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
 610                 if (info->rtc_century && info->rtc_century < 128)
 611                         cmos_rtc.century = info->rtc_century;
 612
 613                 if (info->wake_on && info->wake_off) {
 614                         cmos_rtc.wake_on = info->wake_on;
 615                         cmos_rtc.wake_off = info->wake_off;
 616                 }
 617         }
 618
 619         cmos_rtc.rtc = rtc_device_register(driver_name, dev,
 620                                 &cmos_rtc_ops, THIS_MODULE);
 621         if (IS_ERR(cmos_rtc.rtc)) {
 622                 retval = PTR_ERR(cmos_rtc.rtc);
 623                 goto cleanup0;
 624         }
 625
 626         cmos_rtc.dev = dev;
 627         dev_set_drvdata(dev, &cmos_rtc);
 628         rename_region(ports, cmos_rtc.rtc->dev.bus_id);
 629
 630         spin_lock_irq(&rtc_lock);
 631
 632         /* force periodic irq to CMOS reset default of 1024Hz;
 633          *
 634          * REVISIT it's been reported that at least one x86_64 ALI mobo
 635          * doesn't use 32KHz here ... for portability we might need to
 636          * do something about other clock frequencies.
 637          */
 638         cmos_rtc.rtc->irq_freq = 1024;
 639         if (!hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq))
 640                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
 641
 642         /* disable irqs.
 643          *
 644          * NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
 645          * allegedly some older rtcs need that to handle irqs properly
 646          */
 647         rtc_control = CMOS_READ(RTC_CONTROL);
 648         rtc_control &= ~(RTC_PIE | RTC_AIE | RTC_UIE);
 649         CMOS_WRITE(rtc_control, RTC_CONTROL);
 650         CMOS_READ(RTC_INTR_FLAGS);
 651
 652         spin_unlock_irq(&rtc_lock);
 653
 654         /* FIXME teach the alarm code how to handle binary mode;
 655          * <asm-generic/rtc.h> doesn't know 12-hour mode either.
 656          */
 657         if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY))) {
 658                 dev_dbg(dev, "only 24-hr BCD mode supported\n");
 659                 retval = -ENXIO;
 660                 goto cleanup1;
 661         }
 662
 663         if (is_valid_irq(rtc_irq)) {
 664                 irq_handler_t rtc_cmos_int_handler;
 665
 666                 if (is_hpet_enabled()) {
 667                         int err;
 668
 669                         rtc_cmos_int_handler = hpet_rtc_interrupt;
 670                         err = hpet_register_irq_handler(cmos_interrupt);
 671                         if (err != 0) {
 672                                 printk(KERN_WARNING "hpet_register_irq_handler "
 673                                                 " failed in rtc_init().");
 674                                 goto cleanup1;
 675                         }
 676                 } else
 677                         rtc_cmos_int_handler = cmos_interrupt;
 678
 679                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
 680                                 IRQF_DISABLED, cmos_rtc.rtc->dev.bus_id,
 681                                 cmos_rtc.rtc);
 682                 if (retval < 0) {
 683                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
 684                         goto cleanup1;
 685                 }
 686         }
 687         hpet_rtc_timer_init();
 688
 689         /* export at least the first block of NVRAM */
 690         nvram.size = address_space - NVRAM_OFFSET;
 691         retval = sysfs_create_bin_file(&dev->kobj, &nvram);
 692         if (retval < 0) {
 693                 dev_dbg(dev, "can't create nvram file? %d\n", retval);
 694                 goto cleanup2;
 695         }
 696
 697         pr_info("%s: alarms up to one %s%s\n",
 698                         cmos_rtc.rtc->dev.bus_id,
 699                         is_valid_irq(rtc_irq)
 700                                 ?  (cmos_rtc.mon_alrm
 701                                         ? "year"
 702                                         : (cmos_rtc.day_alrm
 703                                                 ? "month" : "day"))
 704                                 : "no",
 705                         cmos_rtc.century ? ", y3k" : ""
 706                         );
 707
 708         return 0;
 709
 710 cleanup2:
 711         if (is_valid_irq(rtc_irq))
 712                 free_irq(rtc_irq, cmos_rtc.rtc);
 713 cleanup1:
 714         cmos_rtc.dev = NULL;
 715         rtc_device_unregister(cmos_rtc.rtc);
 716 cleanup0:
 717         release_region(ports->start, ports->end + 1 - ports->start);
 718         return retval;
 719 }
 720
 721 static void cmos_do_shutdown(void)
 722 {
 723         unsigned char   rtc_control;
 724
 725         spin_lock_irq(&rtc_lock);
 726         rtc_control = CMOS_READ(RTC_CONTROL);
 727         rtc_control &= ~(RTC_PIE|RTC_AIE|RTC_UIE);
 728         CMOS_WRITE(rtc_control, RTC_CONTROL);
 729         CMOS_READ(RTC_INTR_FLAGS);
 730         spin_unlock_irq(&rtc_lock);
 731 }
 732
 733 static void __exit cmos_do_remove(struct device *dev)
 734 {
 735         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 736         struct resource *ports;
 737
 738         cmos_do_shutdown();
 739
 740         sysfs_remove_bin_file(&dev->kobj, &nvram);
 741
 742         if (is_valid_irq(cmos->irq)) {
 743                 free_irq(cmos->irq, cmos->rtc);
 744                 hpet_unregister_irq_handler(cmos_interrupt);
 745         }
 746
 747         rtc_device_unregister(cmos->rtc);
 748         cmos->rtc = NULL;
 749
 750         ports = cmos->iomem;
 751         release_region(ports->start, ports->end + 1 - ports->start);
 752         cmos->iomem = NULL;
 753
 754         cmos->dev = NULL;
 755         dev_set_drvdata(dev, NULL);
 756 }
 757
 758 #ifdef  CONFIG_PM
 759
 760 static int cmos_suspend(struct device *dev, pm_message_t mesg)
 761 {
 762         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 763         int             do_wake = device_may_wakeup(dev);
 764         unsigned char   tmp;
 765
 766         /* only the alarm might be a wakeup event source */
 767         spin_lock_irq(&rtc_lock);
 768         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
 769         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 770                 unsigned char   irqstat;
 771
 772                 if (do_wake)
 773                         tmp &= ~(RTC_PIE|RTC_UIE);
 774                 else
 775                         tmp &= ~(RTC_PIE|RTC_AIE|RTC_UIE);
 776                 CMOS_WRITE(tmp, RTC_CONTROL);
 777                 irqstat = CMOS_READ(RTC_INTR_FLAGS);
 778                 irqstat &= (tmp & RTC_IRQMASK) | RTC_IRQF;
 779                 if (is_intr(irqstat))
 780                         rtc_update_irq(cmos->rtc, 1, irqstat);
 781         }
 782         spin_unlock_irq(&rtc_lock);
 783
 784         if (tmp & RTC_AIE) {
 785                 cmos->enabled_wake = 1;
 786                 if (cmos->wake_on)
 787                         cmos->wake_on(dev);
 788                 else
 789                         enable_irq_wake(cmos->irq);
 790         }
 791
 792         pr_debug("%s: suspend%s, ctrl %02x\n",
 793                         cmos_rtc.rtc->dev.bus_id,
 794                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
 795                         tmp);
 796
 797         return 0;
 798 }
 799
 800 static int cmos_resume(struct device *dev)
 801 {
 802         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 803         unsigned char   tmp = cmos->suspend_ctrl;
 804
 805         /* re-enable any irqs previously active */
 806         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 807
 808                 if (cmos->enabled_wake) {
 809                         if (cmos->wake_off)
 810                                 cmos->wake_off(dev);
 811                         else
 812                                 disable_irq_wake(cmos->irq);
 813                         cmos->enabled_wake = 0;
 814                 }
 815
 816                 spin_lock_irq(&rtc_lock);
 817                 CMOS_WRITE(tmp, RTC_CONTROL);
 818                 tmp = CMOS_READ(RTC_INTR_FLAGS);
 819                 tmp &= (cmos->suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 820                 if (is_intr(tmp))
 821                         rtc_update_irq(cmos->rtc, 1, tmp);
 822                 spin_unlock_irq(&rtc_lock);
 823         }
 824
 825         pr_debug("%s: resume, ctrl %02x\n",
 826                         cmos_rtc.rtc->dev.bus_id,
 827                         cmos->suspend_ctrl);
 828
 829
 830         return 0;
 831 }
 832
 833 #else
 834 #define cmos_suspend    NULL
 835 #define cmos_resume     NULL
 836 #endif
 837
 838 /*----------------------------------------------------------------*/
 839
 840 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
 841  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
 842  * probably list them in similar PNPBIOS tables; so PNP is more common.
 843  *
 844  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
 845  * predate even PNPBIOS should set up platform_bus devices.
 846  */
 847
 848 #ifdef  CONFIG_PNP
 849
 850 #include <linux/pnp.h>
 851
 852 static int __devinit
 853 cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
 854 {
 855         /* REVISIT paranoia argues for a shutdown notifier, since PNP
 856          * drivers can't provide shutdown() methods to disable IRQs.
 857          * Or better yet, fix PNP to allow those methods...
 858          */
 859         if (pnp_port_start(pnp,0) == 0x70 && !pnp_irq_valid(pnp,0))
 860                 /* Some machines contain a PNP entry for the RTC, but
 861                  * don't define the IRQ. It should always be safe to
 862                  * hardcode it in these cases
 863                  */
 864                 return cmos_do_probe(&pnp->dev, &pnp->res.port_resource[0], 8);
 865         else
 866                 return cmos_do_probe(&pnp->dev,
 867                                      &pnp->res.port_resource[0],
 868                                      pnp->res.irq_resource[0].start);
 869 }
 870
 871 static void __exit cmos_pnp_remove(struct pnp_dev *pnp)
 872 {
 873         cmos_do_remove(&pnp->dev);
 874 }
 875
 876 #ifdef  CONFIG_PM
 877
 878 static int cmos_pnp_suspend(struct pnp_dev *pnp, pm_message_t mesg)
 879 {
 880         return cmos_suspend(&pnp->dev, mesg);
 881 }
 882
 883 static int cmos_pnp_resume(struct pnp_dev *pnp)
 884 {
 885         return cmos_resume(&pnp->dev);
 886 }
 887
 888 #else
 889 #define cmos_pnp_suspend        NULL
 890 #define cmos_pnp_resume         NULL
 891 #endif
 892
 893
 894 static const struct pnp_device_id rtc_ids[] = {
 895         { .id = "PNP0b00", },
 896         { .id = "PNP0b01", },
 897         { .id = "PNP0b02", },
 898         { },
 899 };
 900 MODULE_DEVICE_TABLE(pnp, rtc_ids);
 901
 902 static struct pnp_driver cmos_pnp_driver = {
 903         .name           = (char *) driver_name,
 904         .id_table       = rtc_ids,
 905         .probe          = cmos_pnp_probe,
 906         .remove         = __exit_p(cmos_pnp_remove),
 907
 908         /* flag ensures resume() gets called, and stops syslog spam */
 909         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
 910         .suspend        = cmos_pnp_suspend,
 911         .resume         = cmos_pnp_resume,
 912 };
 913
 914 static int __init cmos_init(void)
 915 {
 916         return pnp_register_driver(&cmos_pnp_driver);
 917 }
 918 module_init(cmos_init);
 919
 920 static void __exit cmos_exit(void)
 921 {
 922         pnp_unregister_driver(&cmos_pnp_driver);
 923 }
 924 module_exit(cmos_exit);
 925
 926 #else   /* no PNP */
 927
 928 /*----------------------------------------------------------------*/
 929
 930 /* Platform setup should have set up an RTC device, when PNP is
 931  * unavailable ... this could happen even on (older) PCs.
 932  */
 933
 934 static int __init cmos_platform_probe(struct platform_device *pdev)
 935 {
 936         return cmos_do_probe(&pdev->dev,
 937                         platform_get_resource(pdev, IORESOURCE_IO, 0),
 938                         platform_get_irq(pdev, 0));
 939 }
 940
 941 static int __exit cmos_platform_remove(struct platform_device *pdev)
 942 {
 943         cmos_do_remove(&pdev->dev);
 944         return 0;
 945 }
 946
 947 static void cmos_platform_shutdown(struct platform_device *pdev)
 948 {
 949         cmos_do_shutdown();
 950 }
 951
 952 static struct platform_driver cmos_platform_driver = {
 953         .remove         = __exit_p(cmos_platform_remove),
 954         .shutdown       = cmos_platform_shutdown,
 955         .driver = {
 956                 .name           = (char *) driver_name,
 957                 .suspend        = cmos_suspend,
 958                 .resume         = cmos_resume,
 959         }
 960 };
 961
 962 static int __init cmos_init(void)
 963 {
 964         return platform_driver_probe(&cmos_platform_driver,
 965                         cmos_platform_probe);
 966 }
 967 module_init(cmos_init);
 968
 969 static void __exit cmos_exit(void)
 970 {
 971         platform_driver_unregister(&cmos_platform_driver);
 972 }
 973 module_exit(cmos_exit);
 974
 975
 976 #endif  /* !PNP */
 977
 978 MODULE_AUTHOR("David Brownell");
 979 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
 980 MODULE_LICENSE("GPL");