kernel/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 #include <linux/dmi.h>
  45
  46 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
  47 #include <asm-generic/rtc.h>
  48
  49 struct cmos_rtc {
  50         struct rtc_device       *rtc;
  51         struct device           *dev;
  52         int                     irq;
  53         struct resource         *iomem;
  54
  55         void                    (*wake_on)(struct device *);
  56         void                    (*wake_off)(struct device *);
  57
  58         u8                      enabled_wake;
  59         u8                      suspend_ctrl;
  60
  61         /* newer hardware extends the original register set */
  62         u8                      day_alrm;
  63         u8                      mon_alrm;
  64         u8                      century;
  65 };
  66
  67 /* both platform and pnp busses use negative numbers for invalid irqs */
  68 #define is_valid_irq(n)         ((n) > 0)
  69
  70 static const char driver_name[] = "rtc_cmos";
  71
  72 /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
  73  * always mask it against the irq enable bits in RTC_CONTROL.  Bit values
  74  * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
  75  */
  76 #define RTC_IRQMASK     (RTC_PF | RTC_AF | RTC_UF)
  77
  78 static inline int is_intr(u8 rtc_intr)
  79 {
  80         if (!(rtc_intr & RTC_IRQF))
  81                 return 0;
  82         return rtc_intr & RTC_IRQMASK;
  83 }
  84
  85 /*----------------------------------------------------------------*/
  86
  87 /* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
  88  * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
  89  * used in a broken "legacy replacement" mode.  The breakage includes
  90  * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
  91  * other (better) use.
  92  *
  93  * When that broken mode is in use, platform glue provides a partial
  94  * emulation of hardware RTC IRQ facilities using HPET #1.  We don't
  95  * want to use HPET for anything except those IRQs though...
  96  */
  97 #ifdef CONFIG_HPET_EMULATE_RTC
  98 #include <asm/hpet.h>
  99 #else
 100
 101 static inline int is_hpet_enabled(void)
 102 {
 103         return 0;
 104 }
 105
 106 static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
 107 {
 108         return 0;
 109 }
 110
 111 static inline int hpet_set_rtc_irq_bit(unsigned long mask)
 112 {
 113         return 0;
 114 }
 115
 116 static inline int
 117 hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
 118 {
 119         return 0;
 120 }
 121
 122 static inline int hpet_set_periodic_freq(unsigned long freq)
 123 {
 124         return 0;
 125 }
 126
 127 static inline int hpet_rtc_dropped_irq(void)
 128 {
 129         return 0;
 130 }
 131
 132 static inline int hpet_rtc_timer_init(void)
 133 {
 134         return 0;
 135 }
 136
 137 extern irq_handler_t hpet_rtc_interrupt;
 138
 139 static inline int hpet_register_irq_handler(irq_handler_t handler)
 140 {
 141         return 0;
 142 }
 143
 144 static inline int hpet_unregister_irq_handler(irq_handler_t handler)
 145 {
 146         return 0;
 147 }
 148
 149 #endif
 150
 151 /*----------------------------------------------------------------*/
 152
 153 #ifdef RTC_PORT
 154
 155 /* Most newer x86 systems have two register banks, the first used
 156  * for RTC and NVRAM and the second only for NVRAM.  Caller must
 157  * own rtc_lock ... and we won't worry about access during NMI.
 158  */
 159 #define can_bank2       true
 160
 161 static inline unsigned char cmos_read_bank2(unsigned char addr)
 162 {
 163         outb(addr, RTC_PORT(2));
 164         return inb(RTC_PORT(3));
 165 }
 166
 167 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 168 {
 169         outb(addr, RTC_PORT(2));
 170         outb(val, RTC_PORT(3));
 171 }
 172
 173 #else
 174
 175 #define can_bank2       false
 176
 177 static inline unsigned char cmos_read_bank2(unsigned char addr)
 178 {
 179         return 0;
 180 }
 181
 182 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 183 {
 184 }
 185
 186 #endif
 187
 188 /*----------------------------------------------------------------*/
 189
 190 static int cmos_read_time(struct device *dev, struct rtc_time *t)
 191 {
 192         /* REVISIT:  if the clock has a "century" register, use
 193          * that instead of the heuristic in get_rtc_time().
 194          * That'll make Y3K compatility (year > 2070) easy!
 195          */
 196         get_rtc_time(t);
 197         return 0;
 198 }
 199
 200 static int cmos_set_time(struct device *dev, struct rtc_time *t)
 201 {
 202         /* REVISIT:  set the "century" register if available
 203          *
 204          * NOTE: this ignores the issue whereby updating the seconds
 205          * takes effect exactly 500ms after we write the register.
 206          * (Also queueing and other delays before we get this far.)
 207          */
 208         return set_rtc_time(t);
 209 }
 210
 211 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 212 {
 213         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 214         unsigned char   rtc_control;
 215
 216         if (!is_valid_irq(cmos->irq))
 217                 return -EIO;
 218
 219         /* Basic alarms only support hour, minute, and seconds fields.
 220          * Some also support day and month, for alarms up to a year in
 221          * the future.
 222          */
 223         t->time.tm_mday = -1;
 224         t->time.tm_mon = -1;
 225
 226         spin_lock_irq(&rtc_lock);
 227         t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
 228         t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
 229         t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 230
 231         if (cmos->day_alrm) {
 232                 /* ignore upper bits on readback per ACPI spec */
 233                 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
 234                 if (!t->time.tm_mday)
 235                         t->time.tm_mday = -1;
 236
 237                 if (cmos->mon_alrm) {
 238                         t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
 239                         if (!t->time.tm_mon)
 240                                 t->time.tm_mon = -1;
 241                 }
 242         }
 243
 244         rtc_control = CMOS_READ(RTC_CONTROL);
 245         spin_unlock_irq(&rtc_lock);
 246
 247         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 248                 if (((unsigned)t->time.tm_sec) < 0x60)
 249                         t->time.tm_sec = bcd2bin(t->time.tm_sec);
 250                 else
 251                         t->time.tm_sec = -1;
 252                 if (((unsigned)t->time.tm_min) < 0x60)
 253                         t->time.tm_min = bcd2bin(t->time.tm_min);
 254                 else
 255                         t->time.tm_min = -1;
 256                 if (((unsigned)t->time.tm_hour) < 0x24)
 257                         t->time.tm_hour = bcd2bin(t->time.tm_hour);
 258                 else
 259                         t->time.tm_hour = -1;
 260
 261                 if (cmos->day_alrm) {
 262                         if (((unsigned)t->time.tm_mday) <= 0x31)
 263                                 t->time.tm_mday = bcd2bin(t->time.tm_mday);
 264                         else
 265                                 t->time.tm_mday = -1;
 266
 267                         if (cmos->mon_alrm) {
 268                                 if (((unsigned)t->time.tm_mon) <= 0x12)
 269                                         t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
 270                                 else
 271                                         t->time.tm_mon = -1;
 272                         }
 273                 }
 274         }
 275         t->time.tm_year = -1;
 276
 277         t->enabled = !!(rtc_control & RTC_AIE);
 278         t->pending = 0;
 279
 280         return 0;
 281 }
 282
 283 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
 284 {
 285         unsigned char   rtc_intr;
 286
 287         /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
 288          * allegedly some older rtcs need that to handle irqs properly
 289          */
 290         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 291
 292         if (is_hpet_enabled())
 293                 return;
 294
 295         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 296         if (is_intr(rtc_intr))
 297                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
 298 }
 299
 300 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
 301 {
 302         unsigned char   rtc_control;
 303
 304         /* flush any pending IRQ status, notably for update irqs,
 305          * before we enable new IRQs
 306          */
 307         rtc_control = CMOS_READ(RTC_CONTROL);
 308         cmos_checkintr(cmos, rtc_control);
 309
 310         rtc_control |= mask;
 311         CMOS_WRITE(rtc_control, RTC_CONTROL);
 312         hpet_set_rtc_irq_bit(mask);
 313
 314         cmos_checkintr(cmos, rtc_control);
 315 }
 316
 317 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
 318 {
 319         unsigned char   rtc_control;
 320
 321         rtc_control = CMOS_READ(RTC_CONTROL);
 322         rtc_control &= ~mask;
 323         CMOS_WRITE(rtc_control, RTC_CONTROL);
 324         hpet_mask_rtc_irq_bit(mask);
 325
 326         cmos_checkintr(cmos, rtc_control);
 327 }
 328
 329 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 330 {
 331         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 332         unsigned char mon, mday, hrs, min, sec, rtc_control;
 333
 334         if (!is_valid_irq(cmos->irq))
 335                 return -EIO;
 336
 337         mon = t->time.tm_mon + 1;
 338         mday = t->time.tm_mday;
 339         hrs = t->time.tm_hour;
 340         min = t->time.tm_min;
 341         sec = t->time.tm_sec;
 342
 343         rtc_control = CMOS_READ(RTC_CONTROL);
 344         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 345                 /* Writing 0xff means "don't care" or "match all".  */
 346                 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
 347                 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 348                 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
 349                 min = (min < 60) ? bin2bcd(min) : 0xff;
 350                 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
 351         }
 352
 353         spin_lock_irq(&rtc_lock);
 354
 355         /* next rtc irq must not be from previous alarm setting */
 356         cmos_irq_disable(cmos, RTC_AIE);
 357
 358         /* update alarm */
 359         CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 360         CMOS_WRITE(min, RTC_MINUTES_ALARM);
 361         CMOS_WRITE(sec, RTC_SECONDS_ALARM);
 362
 363         /* the system may support an "enhanced" alarm */
 364         if (cmos->day_alrm) {
 365                 CMOS_WRITE(mday, cmos->day_alrm);
 366                 if (cmos->mon_alrm)
 367                         CMOS_WRITE(mon, cmos->mon_alrm);
 368         }
 369
 370         /* FIXME the HPET alarm glue currently ignores day_alrm
 371          * and mon_alrm ...
 372          */
 373         hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
 374
 375         if (t->enabled)
 376                 cmos_irq_enable(cmos, RTC_AIE);
 377
 378         spin_unlock_irq(&rtc_lock);
 379
 380         return 0;
 381 }
 382
 383 /*
 384  * Do not disable RTC alarm on shutdown - workaround for b0rked BIOSes.
 385  */
 386 static bool alarm_disable_quirk;
 387
 388 static int __init set_alarm_disable_quirk(const struct dmi_system_id *id)
 389 {
 390         alarm_disable_quirk = true;
 391         pr_info("BIOS has alarm-disable quirk - RTC alarms disabled\n");
 392         return 0;
 393 }
 394
 395 static const struct dmi_system_id rtc_quirks[] __initconst = {
 396         /* https://bugzilla.novell.com/show_bug.cgi?id=805740 */
 397         {
 398                 .callback = set_alarm_disable_quirk,
 399                 .ident    = "IBM Truman",
 400                 .matches  = {
 401                         DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
 402                         DMI_MATCH(DMI_PRODUCT_NAME, "4852570"),
 403                 },
 404         },
 405         /* https://bugzilla.novell.com/show_bug.cgi?id=812592 */
 406         {
 407                 .callback = set_alarm_disable_quirk,
 408                 .ident    = "Gigabyte GA-990XA-UD3",
 409                 .matches  = {
 410                         DMI_MATCH(DMI_SYS_VENDOR,
 411                                         "Gigabyte Technology Co., Ltd."),
 412                         DMI_MATCH(DMI_PRODUCT_NAME, "GA-990XA-UD3"),
 413                 },
 414         },
 415         /* http://permalink.gmane.org/gmane.linux.kernel/1604474 */
 416         {
 417                 .callback = set_alarm_disable_quirk,
 418                 .ident    = "Toshiba Satellite L300",
 419                 .matches  = {
 420                         DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
 421                         DMI_MATCH(DMI_PRODUCT_NAME, "Satellite L300"),
 422                 },
 423         },
 424         {}
 425 };
 426
 427 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 428 {
 429         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 430         unsigned long   flags;
 431
 432         if (!is_valid_irq(cmos->irq))
 433                 return -EINVAL;
 434
 435         if (alarm_disable_quirk)
 436                 return 0;
 437
 438         spin_lock_irqsave(&rtc_lock, flags);
 439
 440         if (enabled)
 441                 cmos_irq_enable(cmos, RTC_AIE);
 442         else
 443                 cmos_irq_disable(cmos, RTC_AIE);
 444
 445         spin_unlock_irqrestore(&rtc_lock, flags);
 446         return 0;
 447 }
 448
 449 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
 450
 451 static int cmos_procfs(struct device *dev, struct seq_file *seq)
 452 {
 453         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 454         unsigned char   rtc_control, valid;
 455
 456         spin_lock_irq(&rtc_lock);
 457         rtc_control = CMOS_READ(RTC_CONTROL);
 458         valid = CMOS_READ(RTC_VALID);
 459         spin_unlock_irq(&rtc_lock);
 460
 461         /* NOTE:  at least ICH6 reports battery status using a different
 462          * (non-RTC) bit; and SQWE is ignored on many current systems.
 463          */
 464         seq_printf(seq,
 465                    "periodic_IRQ\t: %s\n"
 466                    "update_IRQ\t: %s\n"
 467                    "HPET_emulated\t: %s\n"
 468                    // "square_wave\t: %s\n"
 469                    "BCD\t\t: %s\n"
 470                    "DST_enable\t: %s\n"
 471                    "periodic_freq\t: %d\n"
 472                    "batt_status\t: %s\n",
 473                    (rtc_control & RTC_PIE) ? "yes" : "no",
 474                    (rtc_control & RTC_UIE) ? "yes" : "no",
 475                    is_hpet_enabled() ? "yes" : "no",
 476                    // (rtc_control & RTC_SQWE) ? "yes" : "no",
 477                    (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 478                    (rtc_control & RTC_DST_EN) ? "yes" : "no",
 479                    cmos->rtc->irq_freq,
 480                    (valid & RTC_VRT) ? "okay" : "dead");
 481
 482         return 0;
 483 }
 484
 485 #else
 486 #define cmos_procfs     NULL
 487 #endif
 488
 489 static const struct rtc_class_ops cmos_rtc_ops = {
 490         .read_time              = cmos_read_time,
 491         .set_time               = cmos_set_time,
 492         .read_alarm             = cmos_read_alarm,
 493         .set_alarm              = cmos_set_alarm,
 494         .proc                   = cmos_procfs,
 495         .alarm_irq_enable       = cmos_alarm_irq_enable,
 496 };
 497
 498 /*----------------------------------------------------------------*/
 499
 500 /*
 501  * All these chips have at least 64 bytes of address space, shared by
 502  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 503  * by boot firmware.  Modern chips have 128 or 256 bytes.
 504  */
 505
 506 #define NVRAM_OFFSET    (RTC_REG_D + 1)
 507
 508 static ssize_t
 509 cmos_nvram_read(struct file *filp, struct kobject *kobj,
 510                 struct bin_attribute *attr,
 511                 char *buf, loff_t off, size_t count)
 512 {
 513         int     retval;
 514
 515         if (unlikely(off >= attr->size))
 516                 return 0;
 517         if (unlikely(off < 0))
 518                 return -EINVAL;
 519         if ((off + count) > attr->size)
 520                 count = attr->size - off;
 521
 522         off += NVRAM_OFFSET;
 523         spin_lock_irq(&rtc_lock);
 524         for (retval = 0; count; count--, off++, retval++) {
 525                 if (off < 128)
 526                         *buf++ = CMOS_READ(off);
 527                 else if (can_bank2)
 528                         *buf++ = cmos_read_bank2(off);
 529                 else
 530                         break;
 531         }
 532         spin_unlock_irq(&rtc_lock);
 533
 534         return retval;
 535 }
 536
 537 static ssize_t
 538 cmos_nvram_write(struct file *filp, struct kobject *kobj,
 539                 struct bin_attribute *attr,
 540                 char *buf, loff_t off, size_t count)
 541 {
 542         struct cmos_rtc *cmos;
 543         int             retval;
 544
 545         cmos = dev_get_drvdata(container_of(kobj, struct device, kobj));
 546         if (unlikely(off >= attr->size))
 547                 return -EFBIG;
 548         if (unlikely(off < 0))
 549                 return -EINVAL;
 550         if ((off + count) > attr->size)
 551                 count = attr->size - off;
 552
 553         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 554          * checksum on part of the NVRAM data.  That's currently ignored
 555          * here.  If userspace is smart enough to know what fields of
 556          * NVRAM to update, updating checksums is also part of its job.
 557          */
 558         off += NVRAM_OFFSET;
 559         spin_lock_irq(&rtc_lock);
 560         for (retval = 0; count; count--, off++, retval++) {
 561                 /* don't trash RTC registers */
 562                 if (off == cmos->day_alrm
 563                                 || off == cmos->mon_alrm
 564                                 || off == cmos->century)
 565                         buf++;
 566                 else if (off < 128)
 567                         CMOS_WRITE(*buf++, off);
 568                 else if (can_bank2)
 569                         cmos_write_bank2(*buf++, off);
 570                 else
 571                         break;
 572         }
 573         spin_unlock_irq(&rtc_lock);
 574
 575         return retval;
 576 }
 577
 578 static struct bin_attribute nvram = {
 579         .attr = {
 580                 .name   = "nvram",
 581                 .mode   = S_IRUGO | S_IWUSR,
 582         },
 583
 584         .read   = cmos_nvram_read,
 585         .write  = cmos_nvram_write,
 586         /* size gets set up later */
 587 };
 588
 589 /*----------------------------------------------------------------*/
 590
 591 static struct cmos_rtc  cmos_rtc;
 592
 593 static irqreturn_t cmos_interrupt(int irq, void *p)
 594 {
 595         u8              irqstat;
 596         u8              rtc_control;
 597
 598         spin_lock(&rtc_lock);
 599
 600         /* When the HPET interrupt handler calls us, the interrupt
 601          * status is passed as arg1 instead of the irq number.  But
 602          * always clear irq status, even when HPET is in the way.
 603          *
 604          * Note that HPET and RTC are almost certainly out of phase,
 605          * giving different IRQ status ...
 606          */
 607         irqstat = CMOS_READ(RTC_INTR_FLAGS);
 608         rtc_control = CMOS_READ(RTC_CONTROL);
 609         if (is_hpet_enabled())
 610                 irqstat = (unsigned long)irq & 0xF0;
 611
 612         /* If we were suspended, RTC_CONTROL may not be accurate since the
 613          * bios may have cleared it.
 614          */
 615         if (!cmos_rtc.suspend_ctrl)
 616                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 617         else
 618                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 619
 620         /* All Linux RTC alarms should be treated as if they were oneshot.
 621          * Similar code may be needed in system wakeup paths, in case the
 622          * alarm woke the system.
 623          */
 624         if (irqstat & RTC_AIE) {
 625                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 626                 rtc_control &= ~RTC_AIE;
 627                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 628                 hpet_mask_rtc_irq_bit(RTC_AIE);
 629                 CMOS_READ(RTC_INTR_FLAGS);
 630         }
 631         spin_unlock(&rtc_lock);
 632
 633         if (is_intr(irqstat)) {
 634                 rtc_update_irq(p, 1, irqstat);
 635                 return IRQ_HANDLED;
 636         } else
 637                 return IRQ_NONE;
 638 }
 639
 640 #ifdef  CONFIG_PNP
 641 #define INITSECTION
 642
 643 #else
 644 #define INITSECTION     __init
 645 #endif
 646
 647 static int INITSECTION
 648 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 649 {
 650         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
 651         int                             retval = 0;
 652         unsigned char                   rtc_control;
 653         unsigned                        address_space;
 654         u32                             flags = 0;
 655
 656         /* there can be only one ... */
 657         if (cmos_rtc.dev)
 658                 return -EBUSY;
 659
 660         if (!ports)
 661                 return -ENODEV;
 662
 663         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 664          *
 665          * REVISIT non-x86 systems may instead use memory space resources
 666          * (needing ioremap etc), not i/o space resources like this ...
 667          */
 668         if (RTC_IOMAPPED)
 669                 ports = request_region(ports->start, resource_size(ports),
 670                                        driver_name);
 671         else
 672                 ports = request_mem_region(ports->start, resource_size(ports),
 673                                            driver_name);
 674         if (!ports) {
 675                 dev_dbg(dev, "i/o registers already in use\n");
 676                 return -EBUSY;
 677         }
 678
 679         cmos_rtc.irq = rtc_irq;
 680         cmos_rtc.iomem = ports;
 681
 682         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 683          * driver did, but don't reject unknown configs.   Old hardware
 684          * won't address 128 bytes.  Newer chips have multiple banks,
 685          * though they may not be listed in one I/O resource.
 686          */
 687 #if     defined(CONFIG_ATARI)
 688         address_space = 64;
 689 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 690                         || defined(__sparc__) || defined(__mips__) \
 691                         || defined(__powerpc__)
 692         address_space = 128;
 693 #else
 694 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 695         address_space = 128;
 696 #endif
 697         if (can_bank2 && ports->end > (ports->start + 1))
 698                 address_space = 256;
 699
 700         /* For ACPI systems extension info comes from the FADT.  On others,
 701          * board specific setup provides it as appropriate.  Systems where
 702          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 703          * some almost-clones) can provide hooks to make that behave.
 704          *
 705          * Note that ACPI doesn't preclude putting these registers into
 706          * "extended" areas of the chip, including some that we won't yet
 707          * expect CMOS_READ and friends to handle.
 708          */
 709         if (info) {
 710                 if (info->flags)
 711                         flags = info->flags;
 712                 if (info->address_space)
 713                         address_space = info->address_space;
 714
 715                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
 716                         cmos_rtc.day_alrm = info->rtc_day_alarm;
 717                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
 718                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
 719                 if (info->rtc_century && info->rtc_century < 128)
 720                         cmos_rtc.century = info->rtc_century;
 721
 722                 if (info->wake_on && info->wake_off) {
 723                         cmos_rtc.wake_on = info->wake_on;
 724                         cmos_rtc.wake_off = info->wake_off;
 725                 }
 726         }
 727
 728         cmos_rtc.dev = dev;
 729         dev_set_drvdata(dev, &cmos_rtc);
 730
 731         cmos_rtc.rtc = rtc_device_register(driver_name, dev,
 732                                 &cmos_rtc_ops, THIS_MODULE);
 733         if (IS_ERR(cmos_rtc.rtc)) {
 734                 retval = PTR_ERR(cmos_rtc.rtc);
 735                 goto cleanup0;
 736         }
 737
 738         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 739
 740         spin_lock_irq(&rtc_lock);
 741
 742         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
 743                 /* force periodic irq to CMOS reset default of 1024Hz;
 744                  *
 745                  * REVISIT it's been reported that at least one x86_64 ALI
 746                  * mobo doesn't use 32KHz here ... for portability we might
 747                  * need to do something about other clock frequencies.
 748                  */
 749                 cmos_rtc.rtc->irq_freq = 1024;
 750                 hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
 751                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
 752         }
 753
 754         /* disable irqs */
 755         if (is_valid_irq(rtc_irq))
 756                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
 757
 758         rtc_control = CMOS_READ(RTC_CONTROL);
 759
 760         spin_unlock_irq(&rtc_lock);
 761
 762         /* FIXME:
 763          * <asm-generic/rtc.h> doesn't know 12-hour mode either.
 764          */
 765         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
 766                 dev_warn(dev, "only 24-hr supported\n");
 767                 retval = -ENXIO;
 768                 goto cleanup1;
 769         }
 770
 771         if (is_valid_irq(rtc_irq)) {
 772                 irq_handler_t rtc_cmos_int_handler;
 773
 774                 if (is_hpet_enabled()) {
 775                         rtc_cmos_int_handler = hpet_rtc_interrupt;
 776                         retval = hpet_register_irq_handler(cmos_interrupt);
 777                         if (retval) {
 778                                 dev_warn(dev, "hpet_register_irq_handler "
 779                                                 " failed in rtc_init().");
 780                                 goto cleanup1;
 781                         }
 782                 } else
 783                         rtc_cmos_int_handler = cmos_interrupt;
 784
 785                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
 786                                 0, dev_name(&cmos_rtc.rtc->dev),
 787                                 cmos_rtc.rtc);
 788                 if (retval < 0) {
 789                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
 790                         goto cleanup1;
 791                 }
 792         }
 793         hpet_rtc_timer_init();
 794
 795         /* export at least the first block of NVRAM */
 796         nvram.size = address_space - NVRAM_OFFSET;
 797         retval = sysfs_create_bin_file(&dev->kobj, &nvram);
 798         if (retval < 0) {
 799                 dev_dbg(dev, "can't create nvram file? %d\n", retval);
 800                 goto cleanup2;
 801         }
 802
 803         dev_info(dev, "%s%s, %zd bytes nvram%s\n",
 804                 !is_valid_irq(rtc_irq) ? "no alarms" :
 805                         cmos_rtc.mon_alrm ? "alarms up to one year" :
 806                         cmos_rtc.day_alrm ? "alarms up to one month" :
 807                         "alarms up to one day",
 808                 cmos_rtc.century ? ", y3k" : "",
 809                 nvram.size,
 810                 is_hpet_enabled() ? ", hpet irqs" : "");
 811
 812         return 0;
 813
 814 cleanup2:
 815         if (is_valid_irq(rtc_irq))
 816                 free_irq(rtc_irq, cmos_rtc.rtc);
 817 cleanup1:
 818         cmos_rtc.dev = NULL;
 819         rtc_device_unregister(cmos_rtc.rtc);
 820 cleanup0:
 821         if (RTC_IOMAPPED)
 822                 release_region(ports->start, resource_size(ports));
 823         else
 824                 release_mem_region(ports->start, resource_size(ports));
 825         return retval;
 826 }
 827
 828 static void cmos_do_shutdown(int rtc_irq)
 829 {
 830         spin_lock_irq(&rtc_lock);
 831         if (is_valid_irq(rtc_irq))
 832                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
 833         spin_unlock_irq(&rtc_lock);
 834 }
 835
 836 static void __exit cmos_do_remove(struct device *dev)
 837 {
 838         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 839         struct resource *ports;
 840
 841         cmos_do_shutdown(cmos->irq);
 842
 843         sysfs_remove_bin_file(&dev->kobj, &nvram);
 844
 845         if (is_valid_irq(cmos->irq)) {
 846                 free_irq(cmos->irq, cmos->rtc);
 847                 hpet_unregister_irq_handler(cmos_interrupt);
 848         }
 849
 850         rtc_device_unregister(cmos->rtc);
 851         cmos->rtc = NULL;
 852
 853         ports = cmos->iomem;
 854         if (RTC_IOMAPPED)
 855                 release_region(ports->start, resource_size(ports));
 856         else
 857                 release_mem_region(ports->start, resource_size(ports));
 858         cmos->iomem = NULL;
 859
 860         cmos->dev = NULL;
 861 }
 862
 863 #ifdef CONFIG_PM
 864
 865 static int cmos_suspend(struct device *dev)
 866 {
 867         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 868         unsigned char   tmp;
 869
 870         /* only the alarm might be a wakeup event source */
 871         spin_lock_irq(&rtc_lock);
 872         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
 873         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 874                 unsigned char   mask;
 875
 876                 if (device_may_wakeup(dev))
 877                         mask = RTC_IRQMASK & ~RTC_AIE;
 878                 else
 879                         mask = RTC_IRQMASK;
 880                 tmp &= ~mask;
 881                 CMOS_WRITE(tmp, RTC_CONTROL);
 882                 hpet_mask_rtc_irq_bit(mask);
 883
 884                 cmos_checkintr(cmos, tmp);
 885         }
 886         spin_unlock_irq(&rtc_lock);
 887
 888         if (tmp & RTC_AIE) {
 889                 cmos->enabled_wake = 1;
 890                 if (cmos->wake_on)
 891                         cmos->wake_on(dev);
 892                 else
 893                         enable_irq_wake(cmos->irq);
 894         }
 895
 896         dev_dbg(dev, "suspend%s, ctrl %02x\n",
 897                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
 898                         tmp);
 899
 900         return 0;
 901 }
 902
 903 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
 904  * after a detour through G3 "mechanical off", although the ACPI spec
 905  * says wakeup should only work from G1/S4 "hibernate".  To most users,
 906  * distinctions between S4 and S5 are pointless.  So when the hardware
 907  * allows, don't draw that distinction.
 908  */
 909 static inline int cmos_poweroff(struct device *dev)
 910 {
 911         return cmos_suspend(dev);
 912 }
 913
 914 #ifdef  CONFIG_PM_SLEEP
 915
 916 static int cmos_resume(struct device *dev)
 917 {
 918         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 919         unsigned char tmp;
 920
 921         if (cmos->enabled_wake) {
 922                 if (cmos->wake_off)
 923                         cmos->wake_off(dev);
 924                 else
 925                         disable_irq_wake(cmos->irq);
 926                 cmos->enabled_wake = 0;
 927         }
 928
 929         spin_lock_irq(&rtc_lock);
 930         tmp = cmos->suspend_ctrl;
 931         cmos->suspend_ctrl = 0;
 932         /* re-enable any irqs previously active */
 933         if (tmp & RTC_IRQMASK) {
 934                 unsigned char   mask;
 935
 936                 if (device_may_wakeup(dev))
 937                         hpet_rtc_timer_init();
 938
 939                 do {
 940                         CMOS_WRITE(tmp, RTC_CONTROL);
 941                         hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
 942
 943                         mask = CMOS_READ(RTC_INTR_FLAGS);
 944                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
 945                         if (!is_hpet_enabled() || !is_intr(mask))
 946                                 break;
 947
 948                         /* force one-shot behavior if HPET blocked
 949                          * the wake alarm's irq
 950                          */
 951                         rtc_update_irq(cmos->rtc, 1, mask);
 952                         tmp &= ~RTC_AIE;
 953                         hpet_mask_rtc_irq_bit(RTC_AIE);
 954                 } while (mask & RTC_AIE);
 955         }
 956         spin_unlock_irq(&rtc_lock);
 957
 958         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
 959
 960         return 0;
 961 }
 962
 963 #endif
 964 #else
 965
 966 static inline int cmos_poweroff(struct device *dev)
 967 {
 968         return -ENOSYS;
 969 }
 970
 971 #endif
 972
 973 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
 974
 975 /*----------------------------------------------------------------*/
 976
 977 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
 978  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
 979  * probably list them in similar PNPBIOS tables; so PNP is more common.
 980  *
 981  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
 982  * predate even PNPBIOS should set up platform_bus devices.
 983  */
 984
 985 #ifdef  CONFIG_ACPI
 986
 987 #include <linux/acpi.h>
 988
 989 static u32 rtc_handler(void *context)
 990 {
 991         struct device *dev = context;
 992
 993         pm_wakeup_event(dev, 0);
 994         acpi_clear_event(ACPI_EVENT_RTC);
 995         acpi_disable_event(ACPI_EVENT_RTC, 0);
 996         return ACPI_INTERRUPT_HANDLED;
 997 }
 998
 999 static inline void rtc_wake_setup(struct device *dev)
1000 {
1001         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1002         /*
1003          * After the RTC handler is installed, the Fixed_RTC event should
1004          * be disabled. Only when the RTC alarm is set will it be enabled.
1005          */
1006         acpi_clear_event(ACPI_EVENT_RTC);
1007         acpi_disable_event(ACPI_EVENT_RTC, 0);
1008 }
1009
1010 static void rtc_wake_on(struct device *dev)
1011 {
1012         acpi_clear_event(ACPI_EVENT_RTC);
1013         acpi_enable_event(ACPI_EVENT_RTC, 0);
1014 }
1015
1016 static void rtc_wake_off(struct device *dev)
1017 {
1018         acpi_disable_event(ACPI_EVENT_RTC, 0);
1019 }
1020
1021 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1022  * its device node and pass extra config data.  This helps its driver use
1023  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1024  * that this board's RTC is wakeup-capable (per ACPI spec).
1025  */
1026 static struct cmos_rtc_board_info acpi_rtc_info;
1027
1028 static void cmos_wake_setup(struct device *dev)
1029 {
1030         if (acpi_disabled)
1031                 return;
1032
1033         rtc_wake_setup(dev);
1034         acpi_rtc_info.wake_on = rtc_wake_on;
1035         acpi_rtc_info.wake_off = rtc_wake_off;
1036
1037         /* workaround bug in some ACPI tables */
1038         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1039                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1040                         acpi_gbl_FADT.month_alarm);
1041                 acpi_gbl_FADT.month_alarm = 0;
1042         }
1043
1044         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1045         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1046         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1047
1048         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1049         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1050                 dev_info(dev, "RTC can wake from S4\n");
1051
1052         dev->platform_data = &acpi_rtc_info;
1053
1054         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1055         device_init_wakeup(dev, 1);
1056 }
1057
1058 #else
1059
1060 static void cmos_wake_setup(struct device *dev)
1061 {
1062 }
1063
1064 #endif
1065
1066 #ifdef  CONFIG_PNP
1067
1068 #include <linux/pnp.h>
1069
1070 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1071 {
1072         cmos_wake_setup(&pnp->dev);
1073
1074         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0))
1075                 /* Some machines contain a PNP entry for the RTC, but
1076                  * don't define the IRQ. It should always be safe to
1077                  * hardcode it in these cases
1078                  */
1079                 return cmos_do_probe(&pnp->dev,
1080                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), 8);
1081         else
1082                 return cmos_do_probe(&pnp->dev,
1083                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1084                                 pnp_irq(pnp, 0));
1085 }
1086
1087 static void __exit cmos_pnp_remove(struct pnp_dev *pnp)
1088 {
1089         cmos_do_remove(&pnp->dev);
1090 }
1091
1092 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1093 {
1094         struct device *dev = &pnp->dev;
1095         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1096
1097         if (system_state == SYSTEM_POWER_OFF && !cmos_poweroff(dev))
1098                 return;
1099
1100         cmos_do_shutdown(cmos->irq);
1101 }
1102
1103 static const struct pnp_device_id rtc_ids[] = {
1104         { .id = "PNP0b00", },
1105         { .id = "PNP0b01", },
1106         { .id = "PNP0b02", },
1107         { },
1108 };
1109 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1110
1111 static struct pnp_driver cmos_pnp_driver = {
1112         .name           = (char *) driver_name,
1113         .id_table       = rtc_ids,
1114         .probe          = cmos_pnp_probe,
1115         .remove         = __exit_p(cmos_pnp_remove),
1116         .shutdown       = cmos_pnp_shutdown,
1117
1118         /* flag ensures resume() gets called, and stops syslog spam */
1119         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1120         .driver         = {
1121                         .pm = &cmos_pm_ops,
1122         },
1123 };
1124
1125 #endif  /* CONFIG_PNP */
1126
1127 #ifdef CONFIG_OF
1128 static const struct of_device_id of_cmos_match[] = {
1129         {
1130                 .compatible = "motorola,mc146818",
1131         },
1132         { },
1133 };
1134 MODULE_DEVICE_TABLE(of, of_cmos_match);
1135
1136 static __init void cmos_of_init(struct platform_device *pdev)
1137 {
1138         struct device_node *node = pdev->dev.of_node;
1139         struct rtc_time time;
1140         int ret;
1141         const __be32 *val;
1142
1143         if (!node)
1144                 return;
1145
1146         val = of_get_property(node, "ctrl-reg", NULL);
1147         if (val)
1148                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1149
1150         val = of_get_property(node, "freq-reg", NULL);
1151         if (val)
1152                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1153
1154         get_rtc_time(&time);
1155         ret = rtc_valid_tm(&time);
1156         if (ret) {
1157                 struct rtc_time def_time = {
1158                         .tm_year = 1,
1159                         .tm_mday = 1,
1160                 };
1161                 set_rtc_time(&def_time);
1162         }
1163 }
1164 #else
1165 static inline void cmos_of_init(struct platform_device *pdev) {}
1166 #endif
1167 /*----------------------------------------------------------------*/
1168
1169 /* Platform setup should have set up an RTC device, when PNP is
1170  * unavailable ... this could happen even on (older) PCs.
1171  */
1172
1173 static int __init cmos_platform_probe(struct platform_device *pdev)
1174 {
1175         struct resource *resource;
1176         int irq;
1177
1178         cmos_of_init(pdev);
1179         cmos_wake_setup(&pdev->dev);
1180
1181         if (RTC_IOMAPPED)
1182                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1183         else
1184                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1185         irq = platform_get_irq(pdev, 0);
1186         if (irq < 0)
1187                 irq = -1;
1188
1189         return cmos_do_probe(&pdev->dev, resource, irq);
1190 }
1191
1192 static int __exit cmos_platform_remove(struct platform_device *pdev)
1193 {
1194         cmos_do_remove(&pdev->dev);
1195         return 0;
1196 }
1197
1198 static void cmos_platform_shutdown(struct platform_device *pdev)
1199 {
1200         struct device *dev = &pdev->dev;
1201         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1202
1203         if (system_state == SYSTEM_POWER_OFF && !cmos_poweroff(dev))
1204                 return;
1205
1206         cmos_do_shutdown(cmos->irq);
1207 }
1208
1209 /* work with hotplug and coldplug */
1210 MODULE_ALIAS("platform:rtc_cmos");
1211
1212 static struct platform_driver cmos_platform_driver = {
1213         .remove         = __exit_p(cmos_platform_remove),
1214         .shutdown       = cmos_platform_shutdown,
1215         .driver = {
1216                 .name           = driver_name,
1217 #ifdef CONFIG_PM
1218                 .pm             = &cmos_pm_ops,
1219 #endif
1220                 .of_match_table = of_match_ptr(of_cmos_match),
1221         }
1222 };
1223
1224 #ifdef CONFIG_PNP
1225 static bool pnp_driver_registered;
1226 #endif
1227 static bool platform_driver_registered;
1228
1229 static int __init cmos_init(void)
1230 {
1231         int retval = 0;
1232
1233 #ifdef  CONFIG_PNP
1234         retval = pnp_register_driver(&cmos_pnp_driver);
1235         if (retval == 0)
1236                 pnp_driver_registered = true;
1237 #endif
1238
1239         if (!cmos_rtc.dev) {
1240                 retval = platform_driver_probe(&cmos_platform_driver,
1241                                                cmos_platform_probe);
1242                 if (retval == 0)
1243                         platform_driver_registered = true;
1244         }
1245
1246         dmi_check_system(rtc_quirks);
1247
1248         if (retval == 0)
1249                 return 0;
1250
1251 #ifdef  CONFIG_PNP
1252         if (pnp_driver_registered)
1253                 pnp_unregister_driver(&cmos_pnp_driver);
1254 #endif
1255         return retval;
1256 }
1257 module_init(cmos_init);
1258
1259 static void __exit cmos_exit(void)
1260 {
1261 #ifdef  CONFIG_PNP
1262         if (pnp_driver_registered)
1263                 pnp_unregister_driver(&cmos_pnp_driver);
1264 #endif
1265         if (platform_driver_registered)
1266                 platform_driver_unregister(&cmos_platform_driver);
1267 }
1268 module_exit(cmos_exit);
1269
1270
1271 MODULE_AUTHOR("David Brownell");
1272 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1273 MODULE_LICENSE("GPL");