linux/drivers/char/rtc.c
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   1/*
   2 *      Real Time Clock interface for Linux
   3 *
   4 *      Copyright (C) 1996 Paul Gortmaker
   5 *
   6 *      This driver allows use of the real time clock (built into
   7 *      nearly all computers) from user space. It exports the /dev/rtc
   8 *      interface supporting various ioctl() and also the
   9 *      /proc/driver/rtc pseudo-file for status information.
  10 *
  11 *      The ioctls can be used to set the interrupt behaviour and
  12 *      generation rate from the RTC via IRQ 8. Then the /dev/rtc
  13 *      interface can be used to make use of these timer interrupts,
  14 *      be they interval or alarm based.
  15 *
  16 *      The /dev/rtc interface will block on reads until an interrupt
  17 *      has been received. If a RTC interrupt has already happened,
  18 *      it will output an unsigned long and then block. The output value
  19 *      contains the interrupt status in the low byte and the number of
  20 *      interrupts since the last read in the remaining high bytes. The
  21 *      /dev/rtc interface can also be used with the select(2) call.
  22 *
  23 *      This program is free software; you can redistribute it and/or
  24 *      modify it under the terms of the GNU General Public License
  25 *      as published by the Free Software Foundation; either version
  26 *      2 of the License, or (at your option) any later version.
  27 *
  28 *      Based on other minimal char device drivers, like Alan's
  29 *      watchdog, Ted's random, etc. etc.
  30 *
  31 *      1.07    Paul Gortmaker.
  32 *      1.08    Miquel van Smoorenburg: disallow certain things on the
  33 *              DEC Alpha as the CMOS clock is also used for other things.
  34 *      1.09    Nikita Schmidt: epoch support and some Alpha cleanup.
  35 *      1.09a   Pete Zaitcev: Sun SPARC
  36 *      1.09b   Jeff Garzik: Modularize, init cleanup
  37 *      1.09c   Jeff Garzik: SMP cleanup
  38 *      1.10    Paul Barton-Davis: add support for async I/O
  39 *      1.10a   Andrea Arcangeli: Alpha updates
  40 *      1.10b   Andrew Morton: SMP lock fix
  41 *      1.10c   Cesar Barros: SMP locking fixes and cleanup
  42 *      1.10d   Paul Gortmaker: delete paranoia check in rtc_exit
  43 *      1.10e   Maciej W. Rozycki: Handle DECstation's year weirdness.
  44 *      1.11    Takashi Iwai: Kernel access functions
  45 *                            rtc_register/rtc_unregister/rtc_control
  46 *      1.11a   Daniele Bellucci: Audit create_proc_read_entry in rtc_init
  47 *      1.12    Venkatesh Pallipadi: Hooks for emulating rtc on HPET base-timer
  48 *              CONFIG_HPET_EMULATE_RTC
  49 *      1.12a   Maciej W. Rozycki: Handle memory-mapped chips properly.
  50 *      1.12ac  Alan Cox: Allow read access to the day of week register
  51 *      1.12b   David John: Remove calls to the BKL.
  52 */
  53
  54#define RTC_VERSION             "1.12b"
  55
  56/*
  57 *      Note that *all* calls to CMOS_READ and CMOS_WRITE are done with
  58 *      interrupts disabled. Due to the index-port/data-port (0x70/0x71)
  59 *      design of the RTC, we don't want two different things trying to
  60 *      get to it at once. (e.g. the periodic 11 min sync from
  61 *      kernel/time/ntp.c vs. this driver.)
  62 */
  63
  64#include <linux/interrupt.h>
  65#include <linux/module.h>
  66#include <linux/kernel.h>
  67#include <linux/types.h>
  68#include <linux/miscdevice.h>
  69#include <linux/ioport.h>
  70#include <linux/fcntl.h>
  71#include <linux/mc146818rtc.h>
  72#include <linux/init.h>
  73#include <linux/poll.h>
  74#include <linux/proc_fs.h>
  75#include <linux/seq_file.h>
  76#include <linux/spinlock.h>
  77#include <linux/sched.h>
  78#include <linux/sysctl.h>
  79#include <linux/wait.h>
  80#include <linux/bcd.h>
  81#include <linux/delay.h>
  82#include <linux/uaccess.h>
  83#include <linux/ratelimit.h>
  84
  85#include <asm/current.h>
  86
  87#ifdef CONFIG_X86
  88#include <asm/hpet.h>
  89#endif
  90
  91#ifdef CONFIG_SPARC32
  92#include <linux/of.h>
  93#include <linux/of_device.h>
  94#include <asm/io.h>
  95
  96static unsigned long rtc_port;
  97static int rtc_irq;
  98#endif
  99
 100#ifdef  CONFIG_HPET_EMULATE_RTC
 101#undef  RTC_IRQ
 102#endif
 103
 104#ifdef RTC_IRQ
 105static int rtc_has_irq = 1;
 106#endif
 107
 108#ifndef CONFIG_HPET_EMULATE_RTC
 109#define is_hpet_enabled()                       0
 110#define hpet_set_alarm_time(hrs, min, sec)      0
 111#define hpet_set_periodic_freq(arg)             0
 112#define hpet_mask_rtc_irq_bit(arg)              0
 113#define hpet_set_rtc_irq_bit(arg)               0
 114#define hpet_rtc_timer_init()                   do { } while (0)
 115#define hpet_rtc_dropped_irq()                  0
 116#define hpet_register_irq_handler(h)            ({ 0; })
 117#define hpet_unregister_irq_handler(h)          ({ 0; })
 118#ifdef RTC_IRQ
 119static irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
 120{
 121        return 0;
 122}
 123#endif
 124#endif
 125
 126/*
 127 *      We sponge a minor off of the misc major. No need slurping
 128 *      up another valuable major dev number for this. If you add
 129 *      an ioctl, make sure you don't conflict with SPARC's RTC
 130 *      ioctls.
 131 */
 132
 133static struct fasync_struct *rtc_async_queue;
 134
 135static DECLARE_WAIT_QUEUE_HEAD(rtc_wait);
 136
 137#ifdef RTC_IRQ
 138static void rtc_dropped_irq(unsigned long data);
 139
 140static DEFINE_TIMER(rtc_irq_timer, rtc_dropped_irq, 0, 0);
 141#endif
 142
 143static ssize_t rtc_read(struct file *file, char __user *buf,
 144                        size_t count, loff_t *ppos);
 145
 146static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 147static void rtc_get_rtc_time(struct rtc_time *rtc_tm);
 148
 149#ifdef RTC_IRQ
 150static unsigned int rtc_poll(struct file *file, poll_table *wait);
 151#endif
 152
 153static void get_rtc_alm_time(struct rtc_time *alm_tm);
 154#ifdef RTC_IRQ
 155static void set_rtc_irq_bit_locked(unsigned char bit);
 156static void mask_rtc_irq_bit_locked(unsigned char bit);
 157
 158static inline void set_rtc_irq_bit(unsigned char bit)
 159{
 160        spin_lock_irq(&rtc_lock);
 161        set_rtc_irq_bit_locked(bit);
 162        spin_unlock_irq(&rtc_lock);
 163}
 164
 165static void mask_rtc_irq_bit(unsigned char bit)
 166{
 167        spin_lock_irq(&rtc_lock);
 168        mask_rtc_irq_bit_locked(bit);
 169        spin_unlock_irq(&rtc_lock);
 170}
 171#endif
 172
 173#ifdef CONFIG_PROC_FS
 174static int rtc_proc_open(struct inode *inode, struct file *file);
 175#endif
 176
 177/*
 178 *      Bits in rtc_status. (6 bits of room for future expansion)
 179 */
 180
 181#define RTC_IS_OPEN             0x01    /* means /dev/rtc is in use     */
 182#define RTC_TIMER_ON            0x02    /* missed irq timer active      */
 183
 184/*
 185 * rtc_status is never changed by rtc_interrupt, and ioctl/open/close is
 186 * protected by the spin lock rtc_lock. However, ioctl can still disable the
 187 * timer in rtc_status and then with del_timer after the interrupt has read
 188 * rtc_status but before mod_timer is called, which would then reenable the
 189 * timer (but you would need to have an awful timing before you'd trip on it)
 190 */
 191static unsigned long rtc_status;        /* bitmapped status byte.       */
 192static unsigned long rtc_freq;          /* Current periodic IRQ rate    */
 193static unsigned long rtc_irq_data;      /* our output to the world      */
 194static unsigned long rtc_max_user_freq = 64; /* > this, need CAP_SYS_RESOURCE */
 195
 196#ifdef RTC_IRQ
 197/*
 198 * rtc_task_lock nests inside rtc_lock.
 199 */
 200static DEFINE_SPINLOCK(rtc_task_lock);
 201static rtc_task_t *rtc_callback;
 202#endif
 203
 204/*
 205 *      If this driver ever becomes modularised, it will be really nice
 206 *      to make the epoch retain its value across module reload...
 207 */
 208
 209static unsigned long epoch = 1900;      /* year corresponding to 0x00   */
 210
 211static const unsigned char days_in_mo[] =
 212{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
 213
 214/*
 215 * Returns true if a clock update is in progress
 216 */
 217static inline unsigned char rtc_is_updating(void)
 218{
 219        unsigned long flags;
 220        unsigned char uip;
 221
 222        spin_lock_irqsave(&rtc_lock, flags);
 223        uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
 224        spin_unlock_irqrestore(&rtc_lock, flags);
 225        return uip;
 226}
 227
 228#ifdef RTC_IRQ
 229/*
 230 *      A very tiny interrupt handler. It runs with IRQF_DISABLED set,
 231 *      but there is possibility of conflicting with the set_rtc_mmss()
 232 *      call (the rtc irq and the timer irq can easily run at the same
 233 *      time in two different CPUs). So we need to serialize
 234 *      accesses to the chip with the rtc_lock spinlock that each
 235 *      architecture should implement in the timer code.
 236 *      (See ./arch/XXXX/kernel/time.c for the set_rtc_mmss() function.)
 237 */
 238
 239static irqreturn_t rtc_interrupt(int irq, void *dev_id)
 240{
 241        /*
 242         *      Can be an alarm interrupt, update complete interrupt,
 243         *      or a periodic interrupt. We store the status in the
 244         *      low byte and the number of interrupts received since
 245         *      the last read in the remainder of rtc_irq_data.
 246         */
 247
 248        spin_lock(&rtc_lock);
 249        rtc_irq_data += 0x100;
 250        rtc_irq_data &= ~0xff;
 251        if (is_hpet_enabled()) {
 252                /*
 253                 * In this case it is HPET RTC interrupt handler
 254                 * calling us, with the interrupt information
 255                 * passed as arg1, instead of irq.
 256                 */
 257                rtc_irq_data |= (unsigned long)irq & 0xF0;
 258        } else {
 259                rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0);
 260        }
 261
 262        if (rtc_status & RTC_TIMER_ON)
 263                mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);
 264
 265        spin_unlock(&rtc_lock);
 266
 267        /* Now do the rest of the actions */
 268        spin_lock(&rtc_task_lock);
 269        if (rtc_callback)
 270                rtc_callback->func(rtc_callback->private_data);
 271        spin_unlock(&rtc_task_lock);
 272        wake_up_interruptible(&rtc_wait);
 273
 274        kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);
 275
 276        return IRQ_HANDLED;
 277}
 278#endif
 279
 280/*
 281 * sysctl-tuning infrastructure.
 282 */
 283static ctl_table rtc_table[] = {
 284        {
 285                .procname       = "max-user-freq",
 286                .data           = &rtc_max_user_freq,
 287                .maxlen         = sizeof(int),
 288                .mode           = 0644,
 289                .proc_handler   = proc_dointvec,
 290        },
 291        { }
 292};
 293
 294static ctl_table rtc_root[] = {
 295        {
 296                .procname       = "rtc",
 297                .mode           = 0555,
 298                .child          = rtc_table,
 299        },
 300        { }
 301};
 302
 303static ctl_table dev_root[] = {
 304        {
 305                .procname       = "dev",
 306                .mode           = 0555,
 307                .child          = rtc_root,
 308        },
 309        { }
 310};
 311
 312static struct ctl_table_header *sysctl_header;
 313
 314static int __init init_sysctl(void)
 315{
 316    sysctl_header = register_sysctl_table(dev_root);
 317    return 0;
 318}
 319
 320static void __exit cleanup_sysctl(void)
 321{
 322    unregister_sysctl_table(sysctl_header);
 323}
 324
 325/*
 326 *      Now all the various file operations that we export.
 327 */
 328
 329static ssize_t rtc_read(struct file *file, char __user *buf,
 330                        size_t count, loff_t *ppos)
 331{
 332#ifndef RTC_IRQ
 333        return -EIO;
 334#else
 335        DECLARE_WAITQUEUE(wait, current);
 336        unsigned long data;
 337        ssize_t retval;
 338
 339        if (rtc_has_irq == 0)
 340                return -EIO;
 341
 342        /*
 343         * Historically this function used to assume that sizeof(unsigned long)
 344         * is the same in userspace and kernelspace.  This lead to problems
 345         * for configurations with multiple ABIs such a the MIPS o32 and 64
 346         * ABIs supported on the same kernel.  So now we support read of both
 347         * 4 and 8 bytes and assume that's the sizeof(unsigned long) in the
 348         * userspace ABI.
 349         */
 350        if (count != sizeof(unsigned int) && count !=  sizeof(unsigned long))
 351                return -EINVAL;
 352
 353        add_wait_queue(&rtc_wait, &wait);
 354
 355        do {
 356                /* First make it right. Then make it fast. Putting this whole
 357                 * block within the parentheses of a while would be too
 358                 * confusing. And no, xchg() is not the answer. */
 359
 360                __set_current_state(TASK_INTERRUPTIBLE);
 361
 362                spin_lock_irq(&rtc_lock);
 363                data = rtc_irq_data;
 364                rtc_irq_data = 0;
 365                spin_unlock_irq(&rtc_lock);
 366
 367                if (data != 0)
 368                        break;
 369
 370                if (file->f_flags & O_NONBLOCK) {
 371                        retval = -EAGAIN;
 372                        goto out;
 373                }
 374                if (signal_pending(current)) {
 375                        retval = -ERESTARTSYS;
 376                        goto out;
 377                }
 378                schedule();
 379        } while (1);
 380
 381        if (count == sizeof(unsigned int)) {
 382                retval = put_user(data,
 383                                  (unsigned int __user *)buf) ?: sizeof(int);
 384        } else {
 385                retval = put_user(data,
 386                                  (unsigned long __user *)buf) ?: sizeof(long);
 387        }
 388        if (!retval)
 389                retval = count;
 390 out:
 391        __set_current_state(TASK_RUNNING);
 392        remove_wait_queue(&rtc_wait, &wait);
 393
 394        return retval;
 395#endif
 396}
 397
 398static int rtc_do_ioctl(unsigned int cmd, unsigned long arg, int kernel)
 399{
 400        struct rtc_time wtime;
 401
 402#ifdef RTC_IRQ
 403        if (rtc_has_irq == 0) {
 404                switch (cmd) {
 405                case RTC_AIE_OFF:
 406                case RTC_AIE_ON:
 407                case RTC_PIE_OFF:
 408                case RTC_PIE_ON:
 409                case RTC_UIE_OFF:
 410                case RTC_UIE_ON:
 411                case RTC_IRQP_READ:
 412                case RTC_IRQP_SET:
 413                        return -EINVAL;
 414                };
 415        }
 416#endif
 417
 418        switch (cmd) {
 419#ifdef RTC_IRQ
 420        case RTC_AIE_OFF:       /* Mask alarm int. enab. bit    */
 421        {
 422                mask_rtc_irq_bit(RTC_AIE);
 423                return 0;
 424        }
 425        case RTC_AIE_ON:        /* Allow alarm interrupts.      */
 426        {
 427                set_rtc_irq_bit(RTC_AIE);
 428                return 0;
 429        }
 430        case RTC_PIE_OFF:       /* Mask periodic int. enab. bit */
 431        {
 432                /* can be called from isr via rtc_control() */
 433                unsigned long flags;
 434
 435                spin_lock_irqsave(&rtc_lock, flags);
 436                mask_rtc_irq_bit_locked(RTC_PIE);
 437                if (rtc_status & RTC_TIMER_ON) {
 438                        rtc_status &= ~RTC_TIMER_ON;
 439                        del_timer(&rtc_irq_timer);
 440                }
 441                spin_unlock_irqrestore(&rtc_lock, flags);
 442
 443                return 0;
 444        }
 445        case RTC_PIE_ON:        /* Allow periodic ints          */
 446        {
 447                /* can be called from isr via rtc_control() */
 448                unsigned long flags;
 449
 450                /*
 451                 * We don't really want Joe User enabling more
 452                 * than 64Hz of interrupts on a multi-user machine.
 453                 */
 454                if (!kernel && (rtc_freq > rtc_max_user_freq) &&
 455                                                (!capable(CAP_SYS_RESOURCE)))
 456                        return -EACCES;
 457
 458                spin_lock_irqsave(&rtc_lock, flags);
 459                if (!(rtc_status & RTC_TIMER_ON)) {
 460                        mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq +
 461                                        2*HZ/100);
 462                        rtc_status |= RTC_TIMER_ON;
 463                }
 464                set_rtc_irq_bit_locked(RTC_PIE);
 465                spin_unlock_irqrestore(&rtc_lock, flags);
 466
 467                return 0;
 468        }
 469        case RTC_UIE_OFF:       /* Mask ints from RTC updates.  */
 470        {
 471                mask_rtc_irq_bit(RTC_UIE);
 472                return 0;
 473        }
 474        case RTC_UIE_ON:        /* Allow ints for RTC updates.  */
 475        {
 476                set_rtc_irq_bit(RTC_UIE);
 477                return 0;
 478        }
 479#endif
 480        case RTC_ALM_READ:      /* Read the present alarm time */
 481        {
 482                /*
 483                 * This returns a struct rtc_time. Reading >= 0xc0
 484                 * means "don't care" or "match all". Only the tm_hour,
 485                 * tm_min, and tm_sec values are filled in.
 486                 */
 487                memset(&wtime, 0, sizeof(struct rtc_time));
 488                get_rtc_alm_time(&wtime);
 489                break;
 490        }
 491        case RTC_ALM_SET:       /* Store a time into the alarm */
 492        {
 493                /*
 494                 * This expects a struct rtc_time. Writing 0xff means
 495                 * "don't care" or "match all". Only the tm_hour,
 496                 * tm_min and tm_sec are used.
 497                 */
 498                unsigned char hrs, min, sec;
 499                struct rtc_time alm_tm;
 500
 501                if (copy_from_user(&alm_tm, (struct rtc_time __user *)arg,
 502                                   sizeof(struct rtc_time)))
 503                        return -EFAULT;
 504
 505                hrs = alm_tm.tm_hour;
 506                min = alm_tm.tm_min;
 507                sec = alm_tm.tm_sec;
 508
 509                spin_lock_irq(&rtc_lock);
 510                if (hpet_set_alarm_time(hrs, min, sec)) {
 511                        /*
 512                         * Fallthru and set alarm time in CMOS too,
 513                         * so that we will get proper value in RTC_ALM_READ
 514                         */
 515                }
 516                if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) ||
 517                                                        RTC_ALWAYS_BCD) {
 518                        if (sec < 60)
 519                                sec = bin2bcd(sec);
 520                        else
 521                                sec = 0xff;
 522
 523                        if (min < 60)
 524                                min = bin2bcd(min);
 525                        else
 526                                min = 0xff;
 527
 528                        if (hrs < 24)
 529                                hrs = bin2bcd(hrs);
 530                        else
 531                                hrs = 0xff;
 532                }
 533                CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 534                CMOS_WRITE(min, RTC_MINUTES_ALARM);
 535                CMOS_WRITE(sec, RTC_SECONDS_ALARM);
 536                spin_unlock_irq(&rtc_lock);
 537
 538                return 0;
 539        }
 540        case RTC_RD_TIME:       /* Read the time/date from RTC  */
 541        {
 542                memset(&wtime, 0, sizeof(struct rtc_time));
 543                rtc_get_rtc_time(&wtime);
 544                break;
 545        }
 546        case RTC_SET_TIME:      /* Set the RTC */
 547        {
 548                struct rtc_time rtc_tm;
 549                unsigned char mon, day, hrs, min, sec, leap_yr;
 550                unsigned char save_control, save_freq_select;
 551                unsigned int yrs;
 552#ifdef CONFIG_MACH_DECSTATION
 553                unsigned int real_yrs;
 554#endif
 555
 556                if (!capable(CAP_SYS_TIME))
 557                        return -EACCES;
 558
 559                if (copy_from_user(&rtc_tm, (struct rtc_time __user *)arg,
 560                                   sizeof(struct rtc_time)))
 561                        return -EFAULT;
 562
 563                yrs = rtc_tm.tm_year + 1900;
 564                mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
 565                day = rtc_tm.tm_mday;
 566                hrs = rtc_tm.tm_hour;
 567                min = rtc_tm.tm_min;
 568                sec = rtc_tm.tm_sec;
 569
 570                if (yrs < 1970)
 571                        return -EINVAL;
 572
 573                leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
 574
 575                if ((mon > 12) || (day == 0))
 576                        return -EINVAL;
 577
 578                if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
 579                        return -EINVAL;
 580
 581                if ((hrs >= 24) || (min >= 60) || (sec >= 60))
 582                        return -EINVAL;
 583
 584                yrs -= epoch;
 585                if (yrs > 255)          /* They are unsigned */
 586                        return -EINVAL;
 587
 588                spin_lock_irq(&rtc_lock);
 589#ifdef CONFIG_MACH_DECSTATION
 590                real_yrs = yrs;
 591                yrs = 72;
 592
 593                /*
 594                 * We want to keep the year set to 73 until March
 595                 * for non-leap years, so that Feb, 29th is handled
 596                 * correctly.
 597                 */
 598                if (!leap_yr && mon < 3) {
 599                        real_yrs--;
 600                        yrs = 73;
 601                }
 602#endif
 603                /* These limits and adjustments are independent of
 604                 * whether the chip is in binary mode or not.
 605                 */
 606                if (yrs > 169) {
 607                        spin_unlock_irq(&rtc_lock);
 608                        return -EINVAL;
 609                }
 610                if (yrs >= 100)
 611                        yrs -= 100;
 612
 613                if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
 614                    || RTC_ALWAYS_BCD) {
 615                        sec = bin2bcd(sec);
 616                        min = bin2bcd(min);
 617                        hrs = bin2bcd(hrs);
 618                        day = bin2bcd(day);
 619                        mon = bin2bcd(mon);
 620                        yrs = bin2bcd(yrs);
 621                }
 622
 623                save_control = CMOS_READ(RTC_CONTROL);
 624                CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
 625                save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
 626                CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
 627
 628#ifdef CONFIG_MACH_DECSTATION
 629                CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
 630#endif
 631                CMOS_WRITE(yrs, RTC_YEAR);
 632                CMOS_WRITE(mon, RTC_MONTH);
 633                CMOS_WRITE(day, RTC_DAY_OF_MONTH);
 634                CMOS_WRITE(hrs, RTC_HOURS);
 635                CMOS_WRITE(min, RTC_MINUTES);
 636                CMOS_WRITE(sec, RTC_SECONDS);
 637
 638                CMOS_WRITE(save_control, RTC_CONTROL);
 639                CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
 640
 641                spin_unlock_irq(&rtc_lock);
 642                return 0;
 643        }
 644#ifdef RTC_IRQ
 645        case RTC_IRQP_READ:     /* Read the periodic IRQ rate.  */
 646        {
 647                return put_user(rtc_freq, (unsigned long __user *)arg);
 648        }
 649        case RTC_IRQP_SET:      /* Set periodic IRQ rate.       */
 650        {
 651                int tmp = 0;
 652                unsigned char val;
 653                /* can be called from isr via rtc_control() */
 654                unsigned long flags;
 655
 656                /*
 657                 * The max we can do is 8192Hz.
 658                 */
 659                if ((arg < 2) || (arg > 8192))
 660                        return -EINVAL;
 661                /*
 662                 * We don't really want Joe User generating more
 663                 * than 64Hz of interrupts on a multi-user machine.
 664                 */
 665                if (!kernel && (arg > rtc_max_user_freq) &&
 666                                        !capable(CAP_SYS_RESOURCE))
 667                        return -EACCES;
 668
 669                while (arg > (1<<tmp))
 670                        tmp++;
 671
 672                /*
 673                 * Check that the input was really a power of 2.
 674                 */
 675                if (arg != (1<<tmp))
 676                        return -EINVAL;
 677
 678                rtc_freq = arg;
 679
 680                spin_lock_irqsave(&rtc_lock, flags);
 681                if (hpet_set_periodic_freq(arg)) {
 682                        spin_unlock_irqrestore(&rtc_lock, flags);
 683                        return 0;
 684                }
 685
 686                val = CMOS_READ(RTC_FREQ_SELECT) & 0xf0;
 687                val |= (16 - tmp);
 688                CMOS_WRITE(val, RTC_FREQ_SELECT);
 689                spin_unlock_irqrestore(&rtc_lock, flags);
 690                return 0;
 691        }
 692#endif
 693        case RTC_EPOCH_READ:    /* Read the epoch.      */
 694        {
 695                return put_user(epoch, (unsigned long __user *)arg);
 696        }
 697        case RTC_EPOCH_SET:     /* Set the epoch.       */
 698        {
 699                /*
 700                 * There were no RTC clocks before 1900.
 701                 */
 702                if (arg < 1900)
 703                        return -EINVAL;
 704
 705                if (!capable(CAP_SYS_TIME))
 706                        return -EACCES;
 707
 708                epoch = arg;
 709                return 0;
 710        }
 711        default:
 712                return -ENOTTY;
 713        }
 714        return copy_to_user((void __user *)arg,
 715                            &wtime, sizeof wtime) ? -EFAULT : 0;
 716}
 717
 718static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 719{
 720        long ret;
 721        ret = rtc_do_ioctl(cmd, arg, 0);
 722        return ret;
 723}
 724
 725/*
 726 *      We enforce only one user at a time here with the open/close.
 727 *      Also clear the previous interrupt data on an open, and clean
 728 *      up things on a close.
 729 */
 730static int rtc_open(struct inode *inode, struct file *file)
 731{
 732        spin_lock_irq(&rtc_lock);
 733
 734        if (rtc_status & RTC_IS_OPEN)
 735                goto out_busy;
 736
 737        rtc_status |= RTC_IS_OPEN;
 738
 739        rtc_irq_data = 0;
 740        spin_unlock_irq(&rtc_lock);
 741        return 0;
 742
 743out_busy:
 744        spin_unlock_irq(&rtc_lock);
 745        return -EBUSY;
 746}
 747
 748static int rtc_fasync(int fd, struct file *filp, int on)
 749{
 750        return fasync_helper(fd, filp, on, &rtc_async_queue);
 751}
 752
 753static int rtc_release(struct inode *inode, struct file *file)
 754{
 755#ifdef RTC_IRQ
 756        unsigned char tmp;
 757
 758        if (rtc_has_irq == 0)
 759                goto no_irq;
 760
 761        /*
 762         * Turn off all interrupts once the device is no longer
 763         * in use, and clear the data.
 764         */
 765
 766        spin_lock_irq(&rtc_lock);
 767        if (!hpet_mask_rtc_irq_bit(RTC_PIE | RTC_AIE | RTC_UIE)) {
 768                tmp = CMOS_READ(RTC_CONTROL);
 769                tmp &=  ~RTC_PIE;
 770                tmp &=  ~RTC_AIE;
 771                tmp &=  ~RTC_UIE;
 772                CMOS_WRITE(tmp, RTC_CONTROL);
 773                CMOS_READ(RTC_INTR_FLAGS);
 774        }
 775        if (rtc_status & RTC_TIMER_ON) {
 776                rtc_status &= ~RTC_TIMER_ON;
 777                del_timer(&rtc_irq_timer);
 778        }
 779        spin_unlock_irq(&rtc_lock);
 780
 781no_irq:
 782#endif
 783
 784        spin_lock_irq(&rtc_lock);
 785        rtc_irq_data = 0;
 786        rtc_status &= ~RTC_IS_OPEN;
 787        spin_unlock_irq(&rtc_lock);
 788
 789        return 0;
 790}
 791
 792#ifdef RTC_IRQ
 793static unsigned int rtc_poll(struct file *file, poll_table *wait)
 794{
 795        unsigned long l;
 796
 797        if (rtc_has_irq == 0)
 798                return 0;
 799
 800        poll_wait(file, &rtc_wait, wait);
 801
 802        spin_lock_irq(&rtc_lock);
 803        l = rtc_irq_data;
 804        spin_unlock_irq(&rtc_lock);
 805
 806        if (l != 0)
 807                return POLLIN | POLLRDNORM;
 808        return 0;
 809}
 810#endif
 811
 812int rtc_register(rtc_task_t *task)
 813{
 814#ifndef RTC_IRQ
 815        return -EIO;
 816#else
 817        if (task == NULL || task->func == NULL)
 818                return -EINVAL;
 819        spin_lock_irq(&rtc_lock);
 820        if (rtc_status & RTC_IS_OPEN) {
 821                spin_unlock_irq(&rtc_lock);
 822                return -EBUSY;
 823        }
 824        spin_lock(&rtc_task_lock);
 825        if (rtc_callback) {
 826                spin_unlock(&rtc_task_lock);
 827                spin_unlock_irq(&rtc_lock);
 828                return -EBUSY;
 829        }
 830        rtc_status |= RTC_IS_OPEN;
 831        rtc_callback = task;
 832        spin_unlock(&rtc_task_lock);
 833        spin_unlock_irq(&rtc_lock);
 834        return 0;
 835#endif
 836}
 837EXPORT_SYMBOL(rtc_register);
 838
 839int rtc_unregister(rtc_task_t *task)
 840{
 841#ifndef RTC_IRQ
 842        return -EIO;
 843#else
 844        unsigned char tmp;
 845
 846        spin_lock_irq(&rtc_lock);
 847        spin_lock(&rtc_task_lock);
 848        if (rtc_callback != task) {
 849                spin_unlock(&rtc_task_lock);
 850                spin_unlock_irq(&rtc_lock);
 851                return -ENXIO;
 852        }
 853        rtc_callback = NULL;
 854
 855        /* disable controls */
 856        if (!hpet_mask_rtc_irq_bit(RTC_PIE | RTC_AIE | RTC_UIE)) {
 857                tmp = CMOS_READ(RTC_CONTROL);
 858                tmp &= ~RTC_PIE;
 859                tmp &= ~RTC_AIE;
 860                tmp &= ~RTC_UIE;
 861                CMOS_WRITE(tmp, RTC_CONTROL);
 862                CMOS_READ(RTC_INTR_FLAGS);
 863        }
 864        if (rtc_status & RTC_TIMER_ON) {
 865                rtc_status &= ~RTC_TIMER_ON;
 866                del_timer(&rtc_irq_timer);
 867        }
 868        rtc_status &= ~RTC_IS_OPEN;
 869        spin_unlock(&rtc_task_lock);
 870        spin_unlock_irq(&rtc_lock);
 871        return 0;
 872#endif
 873}
 874EXPORT_SYMBOL(rtc_unregister);
 875
 876int rtc_control(rtc_task_t *task, unsigned int cmd, unsigned long arg)
 877{
 878#ifndef RTC_IRQ
 879        return -EIO;
 880#else
 881        unsigned long flags;
 882        if (cmd != RTC_PIE_ON && cmd != RTC_PIE_OFF && cmd != RTC_IRQP_SET)
 883                return -EINVAL;
 884        spin_lock_irqsave(&rtc_task_lock, flags);
 885        if (rtc_callback != task) {
 886                spin_unlock_irqrestore(&rtc_task_lock, flags);
 887                return -ENXIO;
 888        }
 889        spin_unlock_irqrestore(&rtc_task_lock, flags);
 890        return rtc_do_ioctl(cmd, arg, 1);
 891#endif
 892}
 893EXPORT_SYMBOL(rtc_control);
 894
 895/*
 896 *      The various file operations we support.
 897 */
 898
 899static const struct file_operations rtc_fops = {
 900        .owner          = THIS_MODULE,
 901        .llseek         = no_llseek,
 902        .read           = rtc_read,
 903#ifdef RTC_IRQ
 904        .poll           = rtc_poll,
 905#endif
 906        .unlocked_ioctl = rtc_ioctl,
 907        .open           = rtc_open,
 908        .release        = rtc_release,
 909        .fasync         = rtc_fasync,
 910};
 911
 912static struct miscdevice rtc_dev = {
 913        .minor          = RTC_MINOR,
 914        .name           = "rtc",
 915        .fops           = &rtc_fops,
 916};
 917
 918#ifdef CONFIG_PROC_FS
 919static const struct file_operations rtc_proc_fops = {
 920        .owner          = THIS_MODULE,
 921        .open           = rtc_proc_open,
 922        .read           = seq_read,
 923        .llseek         = seq_lseek,
 924        .release        = single_release,
 925};
 926#endif
 927
 928static resource_size_t rtc_size;
 929
 930static struct resource * __init rtc_request_region(resource_size_t size)
 931{
 932        struct resource *r;
 933
 934        if (RTC_IOMAPPED)
 935                r = request_region(RTC_PORT(0), size, "rtc");
 936        else
 937                r = request_mem_region(RTC_PORT(0), size, "rtc");
 938
 939        if (r)
 940                rtc_size = size;
 941
 942        return r;
 943}
 944
 945static void rtc_release_region(void)
 946{
 947        if (RTC_IOMAPPED)
 948                release_region(RTC_PORT(0), rtc_size);
 949        else
 950                release_mem_region(RTC_PORT(0), rtc_size);
 951}
 952
 953static int __init rtc_init(void)
 954{
 955#ifdef CONFIG_PROC_FS
 956        struct proc_dir_entry *ent;
 957#endif
 958#if defined(__alpha__) || defined(__mips__)
 959        unsigned int year, ctrl;
 960        char *guess = NULL;
 961#endif
 962#ifdef CONFIG_SPARC32
 963        struct device_node *ebus_dp;
 964        struct platform_device *op;
 965#else
 966        void *r;
 967#ifdef RTC_IRQ
 968        irq_handler_t rtc_int_handler_ptr;
 969#endif
 970#endif
 971
 972#ifdef CONFIG_SPARC32
 973        for_each_node_by_name(ebus_dp, "ebus") {
 974                struct device_node *dp;
 975                for (dp = ebus_dp; dp; dp = dp->sibling) {
 976                        if (!strcmp(dp->name, "rtc")) {
 977                                op = of_find_device_by_node(dp);
 978                                if (op) {
 979                                        rtc_port = op->resource[0].start;
 980                                        rtc_irq = op->irqs[0];
 981                                        goto found;
 982                                }
 983                        }
 984                }
 985        }
 986        rtc_has_irq = 0;
 987        printk(KERN_ERR "rtc_init: no PC rtc found\n");
 988        return -EIO;
 989
 990found:
 991        if (!rtc_irq) {
 992                rtc_has_irq = 0;
 993                goto no_irq;
 994        }
 995
 996        /*
 997         * XXX Interrupt pin #7 in Espresso is shared between RTC and
 998         * PCI Slot 2 INTA# (and some INTx# in Slot 1).
 999         */
1000        if (request_irq(rtc_irq, rtc_interrupt, IRQF_SHARED, "rtc",
1001                        (void *)&rtc_port)) {
1002                rtc_has_irq = 0;
1003                printk(KERN_ERR "rtc: cannot register IRQ %d\n", rtc_irq);
1004                return -EIO;
1005        }
1006no_irq:
1007#else
1008        r = rtc_request_region(RTC_IO_EXTENT);
1009
1010        /*
1011         * If we've already requested a smaller range (for example, because
1012         * PNPBIOS or ACPI told us how the device is configured), the request
1013         * above might fail because it's too big.
1014         *
1015         * If so, request just the range we actually use.
1016         */
1017        if (!r)
1018                r = rtc_request_region(RTC_IO_EXTENT_USED);
1019        if (!r) {
1020#ifdef RTC_IRQ
1021                rtc_has_irq = 0;
1022#endif
1023                printk(KERN_ERR "rtc: I/O resource %lx is not free.\n",
1024                       (long)(RTC_PORT(0)));
1025                return -EIO;
1026        }
1027
1028#ifdef RTC_IRQ
1029        if (is_hpet_enabled()) {
1030                int err;
1031
1032                rtc_int_handler_ptr = hpet_rtc_interrupt;
1033                err = hpet_register_irq_handler(rtc_interrupt);
1034                if (err != 0) {
1035                        printk(KERN_WARNING "hpet_register_irq_handler failed "
1036                                        "in rtc_init().");
1037                        return err;
1038                }
1039        } else {
1040                rtc_int_handler_ptr = rtc_interrupt;
1041        }
1042
1043        if (request_irq(RTC_IRQ, rtc_int_handler_ptr, IRQF_DISABLED,
1044                        "rtc", NULL)) {
1045                /* Yeah right, seeing as irq 8 doesn't even hit the bus. */
1046                rtc_has_irq = 0;
1047                printk(KERN_ERR "rtc: IRQ %d is not free.\n", RTC_IRQ);
1048                rtc_release_region();
1049
1050                return -EIO;
1051        }
1052        hpet_rtc_timer_init();
1053
1054#endif
1055
1056#endif /* CONFIG_SPARC32 vs. others */
1057
1058        if (misc_register(&rtc_dev)) {
1059#ifdef RTC_IRQ
1060                free_irq(RTC_IRQ, NULL);
1061                hpet_unregister_irq_handler(rtc_interrupt);
1062                rtc_has_irq = 0;
1063#endif
1064                rtc_release_region();
1065                return -ENODEV;
1066        }
1067
1068#ifdef CONFIG_PROC_FS
1069        ent = proc_create("driver/rtc", 0, NULL, &rtc_proc_fops);
1070        if (!ent)
1071                printk(KERN_WARNING "rtc: Failed to register with procfs.\n");
1072#endif
1073
1074#if defined(__alpha__) || defined(__mips__)
1075        rtc_freq = HZ;
1076
1077        /* Each operating system on an Alpha uses its own epoch.
1078           Let's try to guess which one we are using now. */
1079
1080        if (rtc_is_updating() != 0)
1081                msleep(20);
1082
1083        spin_lock_irq(&rtc_lock);
1084        year = CMOS_READ(RTC_YEAR);
1085        ctrl = CMOS_READ(RTC_CONTROL);
1086        spin_unlock_irq(&rtc_lock);
1087
1088        if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
1089                year = bcd2bin(year);       /* This should never happen... */
1090
1091        if (year < 20) {
1092                epoch = 2000;
1093                guess = "SRM (post-2000)";
1094        } else if (year >= 20 && year < 48) {
1095                epoch = 1980;
1096                guess = "ARC console";
1097        } else if (year >= 48 && year < 72) {
1098                epoch = 1952;
1099                guess = "Digital UNIX";
1100#if defined(__mips__)
1101        } else if (year >= 72 && year < 74) {
1102                epoch = 2000;
1103                guess = "Digital DECstation";
1104#else
1105        } else if (year >= 70) {
1106                epoch = 1900;
1107                guess = "Standard PC (1900)";
1108#endif
1109        }
1110        if (guess)
1111                printk(KERN_INFO "rtc: %s epoch (%lu) detected\n",
1112                        guess, epoch);
1113#endif
1114#ifdef RTC_IRQ
1115        if (rtc_has_irq == 0)
1116                goto no_irq2;
1117
1118        spin_lock_irq(&rtc_lock);
1119        rtc_freq = 1024;
1120        if (!hpet_set_periodic_freq(rtc_freq)) {
1121                /*
1122                 * Initialize periodic frequency to CMOS reset default,
1123                 * which is 1024Hz
1124                 */
1125                CMOS_WRITE(((CMOS_READ(RTC_FREQ_SELECT) & 0xF0) | 0x06),
1126                           RTC_FREQ_SELECT);
1127        }
1128        spin_unlock_irq(&rtc_lock);
1129no_irq2:
1130#endif
1131
1132        (void) init_sysctl();
1133
1134        printk(KERN_INFO "Real Time Clock Driver v" RTC_VERSION "\n");
1135
1136        return 0;
1137}
1138
1139static void __exit rtc_exit(void)
1140{
1141        cleanup_sysctl();
1142        remove_proc_entry("driver/rtc", NULL);
1143        misc_deregister(&rtc_dev);
1144
1145#ifdef CONFIG_SPARC32
1146        if (rtc_has_irq)
1147                free_irq(rtc_irq, &rtc_port);
1148#else
1149        rtc_release_region();
1150#ifdef RTC_IRQ
1151        if (rtc_has_irq) {
1152                free_irq(RTC_IRQ, NULL);
1153                hpet_unregister_irq_handler(hpet_rtc_interrupt);
1154        }
1155#endif
1156#endif /* CONFIG_SPARC32 */
1157}
1158
1159module_init(rtc_init);
1160module_exit(rtc_exit);
1161
1162#ifdef RTC_IRQ
1163/*
1164 *      At IRQ rates >= 4096Hz, an interrupt may get lost altogether.
1165 *      (usually during an IDE disk interrupt, with IRQ unmasking off)
1166 *      Since the interrupt handler doesn't get called, the IRQ status
1167 *      byte doesn't get read, and the RTC stops generating interrupts.
1168 *      A timer is set, and will call this function if/when that happens.
1169 *      To get it out of this stalled state, we just read the status.
1170 *      At least a jiffy of interrupts (rtc_freq/HZ) will have been lost.
1171 *      (You *really* shouldn't be trying to use a non-realtime system
1172 *      for something that requires a steady > 1KHz signal anyways.)
1173 */
1174
1175static void rtc_dropped_irq(unsigned long data)
1176{
1177        unsigned long freq;
1178
1179        spin_lock_irq(&rtc_lock);
1180
1181        if (hpet_rtc_dropped_irq()) {
1182                spin_unlock_irq(&rtc_lock);
1183                return;
1184        }
1185
1186        /* Just in case someone disabled the timer from behind our back... */
1187        if (rtc_status & RTC_TIMER_ON)
1188                mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);
1189
1190        rtc_irq_data += ((rtc_freq/HZ)<<8);
1191        rtc_irq_data &= ~0xff;
1192        rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0);     /* restart */
1193
1194        freq = rtc_freq;
1195
1196        spin_unlock_irq(&rtc_lock);
1197
1198        printk_ratelimited(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n",
1199                           freq);
1200
1201        /* Now we have new data */
1202        wake_up_interruptible(&rtc_wait);
1203
1204        kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);
1205}
1206#endif
1207
1208#ifdef CONFIG_PROC_FS
1209/*
1210 *      Info exported via "/proc/driver/rtc".
1211 */
1212
1213static int rtc_proc_show(struct seq_file *seq, void *v)
1214{
1215#define YN(bit) ((ctrl & bit) ? "yes" : "no")
1216#define NY(bit) ((ctrl & bit) ? "no" : "yes")
1217        struct rtc_time tm;
1218        unsigned char batt, ctrl;
1219        unsigned long freq;
1220
1221        spin_lock_irq(&rtc_lock);
1222        batt = CMOS_READ(RTC_VALID) & RTC_VRT;
1223        ctrl = CMOS_READ(RTC_CONTROL);
1224        freq = rtc_freq;
1225        spin_unlock_irq(&rtc_lock);
1226
1227
1228        rtc_get_rtc_time(&tm);
1229
1230        /*
1231         * There is no way to tell if the luser has the RTC set for local
1232         * time or for Universal Standard Time (GMT). Probably local though.
1233         */
1234        seq_printf(seq,
1235                   "rtc_time\t: %02d:%02d:%02d\n"
1236                   "rtc_date\t: %04d-%02d-%02d\n"
1237                   "rtc_epoch\t: %04lu\n",
1238                   tm.tm_hour, tm.tm_min, tm.tm_sec,
1239                   tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);
1240
1241        get_rtc_alm_time(&tm);
1242
1243        /*
1244         * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will
1245         * match any value for that particular field. Values that are
1246         * greater than a valid time, but less than 0xc0 shouldn't appear.
1247         */
1248        seq_puts(seq, "alarm\t\t: ");
1249        if (tm.tm_hour <= 24)
1250                seq_printf(seq, "%02d:", tm.tm_hour);
1251        else
1252                seq_puts(seq, "**:");
1253
1254        if (tm.tm_min <= 59)
1255                seq_printf(seq, "%02d:", tm.tm_min);
1256        else
1257                seq_puts(seq, "**:");
1258
1259        if (tm.tm_sec <= 59)
1260                seq_printf(seq, "%02d\n", tm.tm_sec);
1261        else
1262                seq_puts(seq, "**\n");
1263
1264        seq_printf(seq,
1265                   "DST_enable\t: %s\n"
1266                   "BCD\t\t: %s\n"
1267                   "24hr\t\t: %s\n"
1268                   "square_wave\t: %s\n"
1269                   "alarm_IRQ\t: %s\n"
1270                   "update_IRQ\t: %s\n"
1271                   "periodic_IRQ\t: %s\n"
1272                   "periodic_freq\t: %ld\n"
1273                   "batt_status\t: %s\n",
1274                   YN(RTC_DST_EN),
1275                   NY(RTC_DM_BINARY),
1276                   YN(RTC_24H),
1277                   YN(RTC_SQWE),
1278                   YN(RTC_AIE),
1279                   YN(RTC_UIE),
1280                   YN(RTC_PIE),
1281                   freq,
1282                   batt ? "okay" : "dead");
1283
1284        return  0;
1285#undef YN
1286#undef NY
1287}
1288
1289static int rtc_proc_open(struct inode *inode, struct file *file)
1290{
1291        return single_open(file, rtc_proc_show, NULL);
1292}
1293#endif
1294
1295static void rtc_get_rtc_time(struct rtc_time *rtc_tm)
1296{
1297        unsigned long uip_watchdog = jiffies, flags;
1298        unsigned char ctrl;
1299#ifdef CONFIG_MACH_DECSTATION
1300        unsigned int real_year;
1301#endif
1302
1303        /*
1304         * read RTC once any update in progress is done. The update
1305         * can take just over 2ms. We wait 20ms. There is no need to
1306         * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
1307         * If you need to know *exactly* when a second has started, enable
1308         * periodic update complete interrupts, (via ioctl) and then
1309         * immediately read /dev/rtc which will block until you get the IRQ.
1310         * Once the read clears, read the RTC time (again via ioctl). Easy.
1311         */
1312
1313        while (rtc_is_updating() != 0 &&
1314               time_before(jiffies, uip_watchdog + 2*HZ/100))
1315                cpu_relax();
1316
1317        /*
1318         * Only the values that we read from the RTC are set. We leave
1319         * tm_wday, tm_yday and tm_isdst untouched. Note that while the
1320         * RTC has RTC_DAY_OF_WEEK, we should usually ignore it, as it is
1321         * only updated by the RTC when initially set to a non-zero value.
1322         */
1323        spin_lock_irqsave(&rtc_lock, flags);
1324        rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
1325        rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
1326        rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
1327        rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
1328        rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
1329        rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
1330        /* Only set from 2.6.16 onwards */
1331        rtc_tm->tm_wday = CMOS_READ(RTC_DAY_OF_WEEK);
1332
1333#ifdef CONFIG_MACH_DECSTATION
1334        real_year = CMOS_READ(RTC_DEC_YEAR);
1335#endif
1336        ctrl = CMOS_READ(RTC_CONTROL);
1337        spin_unlock_irqrestore(&rtc_lock, flags);
1338
1339        if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
1340                rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
1341                rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
1342                rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
1343                rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
1344                rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
1345                rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
1346                rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday);
1347        }
1348
1349#ifdef CONFIG_MACH_DECSTATION
1350        rtc_tm->tm_year += real_year - 72;
1351#endif
1352
1353        /*
1354         * Account for differences between how the RTC uses the values
1355         * and how they are defined in a struct rtc_time;
1356         */
1357        rtc_tm->tm_year += epoch - 1900;
1358        if (rtc_tm->tm_year <= 69)
1359                rtc_tm->tm_year += 100;
1360
1361        rtc_tm->tm_mon--;
1362}
1363
1364static void get_rtc_alm_time(struct rtc_time *alm_tm)
1365{
1366        unsigned char ctrl;
1367
1368        /*
1369         * Only the values that we read from the RTC are set. That
1370         * means only tm_hour, tm_min, and tm_sec.
1371         */
1372        spin_lock_irq(&rtc_lock);
1373        alm_tm->tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
1374        alm_tm->tm_min = CMOS_READ(RTC_MINUTES_ALARM);
1375        alm_tm->tm_hour = CMOS_READ(RTC_HOURS_ALARM);
1376        ctrl = CMOS_READ(RTC_CONTROL);
1377        spin_unlock_irq(&rtc_lock);
1378
1379        if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
1380                alm_tm->tm_sec = bcd2bin(alm_tm->tm_sec);
1381                alm_tm->tm_min = bcd2bin(alm_tm->tm_min);
1382                alm_tm->tm_hour = bcd2bin(alm_tm->tm_hour);
1383        }
1384}
1385
1386#ifdef RTC_IRQ
1387/*
1388 * Used to disable/enable interrupts for any one of UIE, AIE, PIE.
1389 * Rumour has it that if you frob the interrupt enable/disable
1390 * bits in RTC_CONTROL, you should read RTC_INTR_FLAGS, to
1391 * ensure you actually start getting interrupts. Probably for
1392 * compatibility with older/broken chipset RTC implementations.
1393 * We also clear out any old irq data after an ioctl() that
1394 * meddles with the interrupt enable/disable bits.
1395 */
1396
1397static void mask_rtc_irq_bit_locked(unsigned char bit)
1398{
1399        unsigned char val;
1400
1401        if (hpet_mask_rtc_irq_bit(bit))
1402                return;
1403        val = CMOS_READ(RTC_CONTROL);
1404        val &=  ~bit;
1405        CMOS_WRITE(val, RTC_CONTROL);
1406        CMOS_READ(RTC_INTR_FLAGS);
1407
1408        rtc_irq_data = 0;
1409}
1410
1411static void set_rtc_irq_bit_locked(unsigned char bit)
1412{
1413        unsigned char val;
1414
1415        if (hpet_set_rtc_irq_bit(bit))
1416                return;
1417        val = CMOS_READ(RTC_CONTROL);
1418        val |= bit;
1419        CMOS_WRITE(val, RTC_CONTROL);
1420        CMOS_READ(RTC_INTR_FLAGS);
1421
1422        rtc_irq_data = 0;
1423}
1424#endif
1425
1426MODULE_AUTHOR("Paul Gortmaker");
1427MODULE_LICENSE("GPL");
1428MODULE_ALIAS_MISCDEV(RTC_MINOR);
1429
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