drivers/char/rtc.c

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This source file includes following definitions.
hpet_rtc_interrupt
set_rtc_irq_bit
mask_rtc_irq_bit
rtc_is_updating
rtc_interrupt
init_sysctl
cleanup_sysctl
rtc_read
rtc_do_ioctl
rtc_ioctl
rtc_open
rtc_fasync
rtc_release
rtc_poll
rtc_request_region
rtc_release_region
rtc_init
rtc_exit
rtc_dropped_irq
rtc_proc_show
rtc_get_rtc_time
get_rtc_alm_time
mask_rtc_irq_bit_locked
set_rtc_irq_bit_locked
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      Real Time Clock interface for Linux
   4  *
   5  *      Copyright (C) 1996 Paul Gortmaker
   6  *
   7  *      This driver allows use of the real time clock (built into
   8  *      nearly all computers) from user space. It exports the /dev/rtc
   9  *      interface supporting various ioctl() and also the
  10  *      /proc/driver/rtc pseudo-file for status information.
  11  *
  12  *      The ioctls can be used to set the interrupt behaviour and
  13  *      generation rate from the RTC via IRQ 8. Then the /dev/rtc
  14  *      interface can be used to make use of these timer interrupts,
  15  *      be they interval or alarm based.
  16  *
  17  *      The /dev/rtc interface will block on reads until an interrupt
  18  *      has been received. If a RTC interrupt has already happened,
  19  *      it will output an unsigned long and then block. The output value
  20  *      contains the interrupt status in the low byte and the number of
  21  *      interrupts since the last read in the remaining high bytes. The
  22  *      /dev/rtc interface can also be used with the select(2) call.
  23  *
  24  *      Based on other minimal char device drivers, like Alan's
  25  *      watchdog, Ted's random, etc. etc.
  26  *
  27  *      1.07    Paul Gortmaker.
  28  *      1.08    Miquel van Smoorenburg: disallow certain things on the
  29  *              DEC Alpha as the CMOS clock is also used for other things.
  30  *      1.09    Nikita Schmidt: epoch support and some Alpha cleanup.
  31  *      1.09a   Pete Zaitcev: Sun SPARC
  32  *      1.09b   Jeff Garzik: Modularize, init cleanup
  33  *      1.09c   Jeff Garzik: SMP cleanup
  34  *      1.10    Paul Barton-Davis: add support for async I/O
  35  *      1.10a   Andrea Arcangeli: Alpha updates
  36  *      1.10b   Andrew Morton: SMP lock fix
  37  *      1.10c   Cesar Barros: SMP locking fixes and cleanup
  38  *      1.10d   Paul Gortmaker: delete paranoia check in rtc_exit
  39  *      1.10e   Maciej W. Rozycki: Handle DECstation's year weirdness.
  40  *      1.11    Takashi Iwai: Kernel access functions
  41  *                            rtc_register/rtc_unregister/rtc_control
  42  *      1.11a   Daniele Bellucci: Audit create_proc_read_entry in rtc_init
  43  *      1.12    Venkatesh Pallipadi: Hooks for emulating rtc on HPET base-timer
  44  *              CONFIG_HPET_EMULATE_RTC
  45  *      1.12a   Maciej W. Rozycki: Handle memory-mapped chips properly.
  46  *      1.12ac  Alan Cox: Allow read access to the day of week register
  47  *      1.12b   David John: Remove calls to the BKL.
  48  */
  49 
  50 #define RTC_VERSION             "1.12b"
  51 
  52 /*
  53  *      Note that *all* calls to CMOS_READ and CMOS_WRITE are done with
  54  *      interrupts disabled. Due to the index-port/data-port (0x70/0x71)
  55  *      design of the RTC, we don't want two different things trying to
  56  *      get to it at once. (e.g. the periodic 11 min sync from
  57  *      kernel/time/ntp.c vs. this driver.)
  58  */
  59 
  60 #include <linux/interrupt.h>
  61 #include <linux/module.h>
  62 #include <linux/kernel.h>
  63 #include <linux/types.h>
  64 #include <linux/miscdevice.h>
  65 #include <linux/ioport.h>
  66 #include <linux/fcntl.h>
  67 #include <linux/mc146818rtc.h>
  68 #include <linux/init.h>
  69 #include <linux/poll.h>
  70 #include <linux/proc_fs.h>
  71 #include <linux/seq_file.h>
  72 #include <linux/spinlock.h>
  73 #include <linux/sched/signal.h>
  74 #include <linux/sysctl.h>
  75 #include <linux/wait.h>
  76 #include <linux/bcd.h>
  77 #include <linux/delay.h>
  78 #include <linux/uaccess.h>
  79 #include <linux/ratelimit.h>
  80 
  81 #include <asm/current.h>
  82 
  83 #ifdef CONFIG_X86
  84 #include <asm/hpet.h>
  85 #endif
  86 
  87 #ifdef CONFIG_SPARC32
  88 #include <linux/of.h>
  89 #include <linux/of_device.h>
  90 #include <asm/io.h>
  91 
  92 static unsigned long rtc_port;
  93 static int rtc_irq;
  94 #endif
  95 
  96 #ifdef  CONFIG_HPET_EMULATE_RTC
  97 #undef  RTC_IRQ
  98 #endif
  99 
 100 #ifdef RTC_IRQ
 101 static int rtc_has_irq = 1;
 102 #endif
 103 
 104 #ifndef CONFIG_HPET_EMULATE_RTC
 105 #define is_hpet_enabled()                       0
 106 #define hpet_set_alarm_time(hrs, min, sec)      0
 107 #define hpet_set_periodic_freq(arg)             0
 108 #define hpet_mask_rtc_irq_bit(arg)              0
 109 #define hpet_set_rtc_irq_bit(arg)               0
 110 #define hpet_rtc_timer_init()                   do { } while (0)
 111 #define hpet_rtc_dropped_irq()                  0
 112 #define hpet_register_irq_handler(h)            ({ 0; })
 113 #define hpet_unregister_irq_handler(h)          ({ 0; })
 114 #ifdef RTC_IRQ
 115 static irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
 116 {
 117         return 0;
 118 }
 119 #endif
 120 #endif
 121 
 122 /*
 123  *      We sponge a minor off of the misc major. No need slurping
 124  *      up another valuable major dev number for this. If you add
 125  *      an ioctl, make sure you don't conflict with SPARC's RTC
 126  *      ioctls.
 127  */
 128 
 129 static struct fasync_struct *rtc_async_queue;
 130 
 131 static DECLARE_WAIT_QUEUE_HEAD(rtc_wait);
 132 
 133 #ifdef RTC_IRQ
 134 static void rtc_dropped_irq(struct timer_list *unused);
 135 
 136 static DEFINE_TIMER(rtc_irq_timer, rtc_dropped_irq);
 137 #endif
 138 
 139 static ssize_t rtc_read(struct file *file, char __user *buf,
 140                         size_t count, loff_t *ppos);
 141 
 142 static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 143 static void rtc_get_rtc_time(struct rtc_time *rtc_tm);
 144 
 145 #ifdef RTC_IRQ
 146 static __poll_t rtc_poll(struct file *file, poll_table *wait);
 147 #endif
 148 
 149 static void get_rtc_alm_time(struct rtc_time *alm_tm);
 150 #ifdef RTC_IRQ
 151 static void set_rtc_irq_bit_locked(unsigned char bit);
 152 static void mask_rtc_irq_bit_locked(unsigned char bit);
 153 
 154 static inline void set_rtc_irq_bit(unsigned char bit)
 155 {
 156         spin_lock_irq(&rtc_lock);
 157         set_rtc_irq_bit_locked(bit);
 158         spin_unlock_irq(&rtc_lock);
 159 }
 160 
 161 static void mask_rtc_irq_bit(unsigned char bit)
 162 {
 163         spin_lock_irq(&rtc_lock);
 164         mask_rtc_irq_bit_locked(bit);
 165         spin_unlock_irq(&rtc_lock);
 166 }
 167 #endif
 168 
 169 #ifdef CONFIG_PROC_FS
 170 static int rtc_proc_show(struct seq_file *seq, void *v);
 171 #endif
 172 
 173 /*
 174  *      Bits in rtc_status. (6 bits of room for future expansion)
 175  */
 176 
 177 #define RTC_IS_OPEN             0x01    /* means /dev/rtc is in use     */
 178 #define RTC_TIMER_ON            0x02    /* missed irq timer active      */
 179 
 180 /*
 181  * rtc_status is never changed by rtc_interrupt, and ioctl/open/close is
 182  * protected by the spin lock rtc_lock. However, ioctl can still disable the
 183  * timer in rtc_status and then with del_timer after the interrupt has read
 184  * rtc_status but before mod_timer is called, which would then reenable the
 185  * timer (but you would need to have an awful timing before you'd trip on it)
 186  */
 187 static unsigned long rtc_status;        /* bitmapped status byte.       */
 188 static unsigned long rtc_freq;          /* Current periodic IRQ rate    */
 189 static unsigned long rtc_irq_data;      /* our output to the world      */
 190 static unsigned long rtc_max_user_freq = 64; /* > this, need CAP_SYS_RESOURCE */
 191 
 192 /*
 193  *      If this driver ever becomes modularised, it will be really nice
 194  *      to make the epoch retain its value across module reload...
 195  */
 196 
 197 static unsigned long epoch = 1900;      /* year corresponding to 0x00   */
 198 
 199 static const unsigned char days_in_mo[] =
 200 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
 201 
 202 /*
 203  * Returns true if a clock update is in progress
 204  */
 205 static inline unsigned char rtc_is_updating(void)
 206 {
 207         unsigned long flags;
 208         unsigned char uip;
 209 
 210         spin_lock_irqsave(&rtc_lock, flags);
 211         uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
 212         spin_unlock_irqrestore(&rtc_lock, flags);
 213         return uip;
 214 }
 215 
 216 #ifdef RTC_IRQ
 217 /*
 218  *      A very tiny interrupt handler. It runs with interrupts disabled,
 219  *      but there is possibility of conflicting with the set_rtc_mmss()
 220  *      call (the rtc irq and the timer irq can easily run at the same
 221  *      time in two different CPUs). So we need to serialize
 222  *      accesses to the chip with the rtc_lock spinlock that each
 223  *      architecture should implement in the timer code.
 224  *      (See ./arch/XXXX/kernel/time.c for the set_rtc_mmss() function.)
 225  */
 226 
 227 static irqreturn_t rtc_interrupt(int irq, void *dev_id)
 228 {
 229         /*
 230          *      Can be an alarm interrupt, update complete interrupt,
 231          *      or a periodic interrupt. We store the status in the
 232          *      low byte and the number of interrupts received since
 233          *      the last read in the remainder of rtc_irq_data.
 234          */
 235 
 236         spin_lock(&rtc_lock);
 237         rtc_irq_data += 0x100;
 238         rtc_irq_data &= ~0xff;
 239         if (is_hpet_enabled()) {
 240                 /*
 241                  * In this case it is HPET RTC interrupt handler
 242                  * calling us, with the interrupt information
 243                  * passed as arg1, instead of irq.
 244                  */
 245                 rtc_irq_data |= (unsigned long)irq & 0xF0;
 246         } else {
 247                 rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0);
 248         }
 249 
 250         if (rtc_status & RTC_TIMER_ON)
 251                 mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);
 252 
 253         spin_unlock(&rtc_lock);
 254 
 255         wake_up_interruptible(&rtc_wait);
 256 
 257         kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);
 258 
 259         return IRQ_HANDLED;
 260 }
 261 #endif
 262 
 263 /*
 264  * sysctl-tuning infrastructure.
 265  */
 266 static struct ctl_table rtc_table[] = {
 267         {
 268                 .procname       = "max-user-freq",
 269                 .data           = &rtc_max_user_freq,
 270                 .maxlen         = sizeof(int),
 271                 .mode           = 0644,
 272                 .proc_handler   = proc_dointvec,
 273         },
 274         { }
 275 };
 276 
 277 static struct ctl_table rtc_root[] = {
 278         {
 279                 .procname       = "rtc",
 280                 .mode           = 0555,
 281                 .child          = rtc_table,
 282         },
 283         { }
 284 };
 285 
 286 static struct ctl_table dev_root[] = {
 287         {
 288                 .procname       = "dev",
 289                 .mode           = 0555,
 290                 .child          = rtc_root,
 291         },
 292         { }
 293 };
 294 
 295 static struct ctl_table_header *sysctl_header;
 296 
 297 static int __init init_sysctl(void)
 298 {
 299     sysctl_header = register_sysctl_table(dev_root);
 300     return 0;
 301 }
 302 
 303 static void __exit cleanup_sysctl(void)
 304 {
 305     unregister_sysctl_table(sysctl_header);
 306 }
 307 
 308 /*
 309  *      Now all the various file operations that we export.
 310  */
 311 
 312 static ssize_t rtc_read(struct file *file, char __user *buf,
 313                         size_t count, loff_t *ppos)
 314 {
 315 #ifndef RTC_IRQ
 316         return -EIO;
 317 #else
 318         DECLARE_WAITQUEUE(wait, current);
 319         unsigned long data;
 320         ssize_t retval;
 321 
 322         if (rtc_has_irq == 0)
 323                 return -EIO;
 324 
 325         /*
 326          * Historically this function used to assume that sizeof(unsigned long)
 327          * is the same in userspace and kernelspace.  This lead to problems
 328          * for configurations with multiple ABIs such a the MIPS o32 and 64
 329          * ABIs supported on the same kernel.  So now we support read of both
 330          * 4 and 8 bytes and assume that's the sizeof(unsigned long) in the
 331          * userspace ABI.
 332          */
 333         if (count != sizeof(unsigned int) && count !=  sizeof(unsigned long))
 334                 return -EINVAL;
 335 
 336         add_wait_queue(&rtc_wait, &wait);
 337 
 338         do {
 339                 /* First make it right. Then make it fast. Putting this whole
 340                  * block within the parentheses of a while would be too
 341                  * confusing. And no, xchg() is not the answer. */
 342 
 343                 __set_current_state(TASK_INTERRUPTIBLE);
 344 
 345                 spin_lock_irq(&rtc_lock);
 346                 data = rtc_irq_data;
 347                 rtc_irq_data = 0;
 348                 spin_unlock_irq(&rtc_lock);
 349 
 350                 if (data != 0)
 351                         break;
 352 
 353                 if (file->f_flags & O_NONBLOCK) {
 354                         retval = -EAGAIN;
 355                         goto out;
 356                 }
 357                 if (signal_pending(current)) {
 358                         retval = -ERESTARTSYS;
 359                         goto out;
 360                 }
 361                 schedule();
 362         } while (1);
 363 
 364         if (count == sizeof(unsigned int)) {
 365                 retval = put_user(data,
 366                                   (unsigned int __user *)buf) ?: sizeof(int);
 367         } else {
 368                 retval = put_user(data,
 369                                   (unsigned long __user *)buf) ?: sizeof(long);
 370         }
 371         if (!retval)
 372                 retval = count;
 373  out:
 374         __set_current_state(TASK_RUNNING);
 375         remove_wait_queue(&rtc_wait, &wait);
 376 
 377         return retval;
 378 #endif
 379 }
 380 
 381 static int rtc_do_ioctl(unsigned int cmd, unsigned long arg, int kernel)
 382 {
 383         struct rtc_time wtime;
 384 
 385 #ifdef RTC_IRQ
 386         if (rtc_has_irq == 0) {
 387                 switch (cmd) {
 388                 case RTC_AIE_OFF:
 389                 case RTC_AIE_ON:
 390                 case RTC_PIE_OFF:
 391                 case RTC_PIE_ON:
 392                 case RTC_UIE_OFF:
 393                 case RTC_UIE_ON:
 394                 case RTC_IRQP_READ:
 395                 case RTC_IRQP_SET:
 396                         return -EINVAL;
 397                 }
 398         }
 399 #endif
 400 
 401         switch (cmd) {
 402 #ifdef RTC_IRQ
 403         case RTC_AIE_OFF:       /* Mask alarm int. enab. bit    */
 404         {
 405                 mask_rtc_irq_bit(RTC_AIE);
 406                 return 0;
 407         }
 408         case RTC_AIE_ON:        /* Allow alarm interrupts.      */
 409         {
 410                 set_rtc_irq_bit(RTC_AIE);
 411                 return 0;
 412         }
 413         case RTC_PIE_OFF:       /* Mask periodic int. enab. bit */
 414         {
 415                 /* can be called from isr via rtc_control() */
 416                 unsigned long flags;
 417 
 418                 spin_lock_irqsave(&rtc_lock, flags);
 419                 mask_rtc_irq_bit_locked(RTC_PIE);
 420                 if (rtc_status & RTC_TIMER_ON) {
 421                         rtc_status &= ~RTC_TIMER_ON;
 422                         del_timer(&rtc_irq_timer);
 423                 }
 424                 spin_unlock_irqrestore(&rtc_lock, flags);
 425 
 426                 return 0;
 427         }
 428         case RTC_PIE_ON:        /* Allow periodic ints          */
 429         {
 430                 /* can be called from isr via rtc_control() */
 431                 unsigned long flags;
 432 
 433                 /*
 434                  * We don't really want Joe User enabling more
 435                  * than 64Hz of interrupts on a multi-user machine.
 436                  */
 437                 if (!kernel && (rtc_freq > rtc_max_user_freq) &&
 438                                                 (!capable(CAP_SYS_RESOURCE)))
 439                         return -EACCES;
 440 
 441                 spin_lock_irqsave(&rtc_lock, flags);
 442                 if (!(rtc_status & RTC_TIMER_ON)) {
 443                         mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq +
 444                                         2*HZ/100);
 445                         rtc_status |= RTC_TIMER_ON;
 446                 }
 447                 set_rtc_irq_bit_locked(RTC_PIE);
 448                 spin_unlock_irqrestore(&rtc_lock, flags);
 449 
 450                 return 0;
 451         }
 452         case RTC_UIE_OFF:       /* Mask ints from RTC updates.  */
 453         {
 454                 mask_rtc_irq_bit(RTC_UIE);
 455                 return 0;
 456         }
 457         case RTC_UIE_ON:        /* Allow ints for RTC updates.  */
 458         {
 459                 set_rtc_irq_bit(RTC_UIE);
 460                 return 0;
 461         }
 462 #endif
 463         case RTC_ALM_READ:      /* Read the present alarm time */
 464         {
 465                 /*
 466                  * This returns a struct rtc_time. Reading >= 0xc0
 467                  * means "don't care" or "match all". Only the tm_hour,
 468                  * tm_min, and tm_sec values are filled in.
 469                  */
 470                 memset(&wtime, 0, sizeof(struct rtc_time));
 471                 get_rtc_alm_time(&wtime);
 472                 break;
 473         }
 474         case RTC_ALM_SET:       /* Store a time into the alarm */
 475         {
 476                 /*
 477                  * This expects a struct rtc_time. Writing 0xff means
 478                  * "don't care" or "match all". Only the tm_hour,
 479                  * tm_min and tm_sec are used.
 480                  */
 481                 unsigned char hrs, min, sec;
 482                 struct rtc_time alm_tm;
 483 
 484                 if (copy_from_user(&alm_tm, (struct rtc_time __user *)arg,
 485                                    sizeof(struct rtc_time)))
 486                         return -EFAULT;
 487 
 488                 hrs = alm_tm.tm_hour;
 489                 min = alm_tm.tm_min;
 490                 sec = alm_tm.tm_sec;
 491 
 492                 spin_lock_irq(&rtc_lock);
 493                 if (hpet_set_alarm_time(hrs, min, sec)) {
 494                         /*
 495                          * Fallthru and set alarm time in CMOS too,
 496                          * so that we will get proper value in RTC_ALM_READ
 497                          */
 498                 }
 499                 if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) ||
 500                                                         RTC_ALWAYS_BCD) {
 501                         if (sec < 60)
 502                                 sec = bin2bcd(sec);
 503                         else
 504                                 sec = 0xff;
 505 
 506                         if (min < 60)
 507                                 min = bin2bcd(min);
 508                         else
 509                                 min = 0xff;
 510 
 511                         if (hrs < 24)
 512                                 hrs = bin2bcd(hrs);
 513                         else
 514                                 hrs = 0xff;
 515                 }
 516                 CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 517                 CMOS_WRITE(min, RTC_MINUTES_ALARM);
 518                 CMOS_WRITE(sec, RTC_SECONDS_ALARM);
 519                 spin_unlock_irq(&rtc_lock);
 520 
 521                 return 0;
 522         }
 523         case RTC_RD_TIME:       /* Read the time/date from RTC  */
 524         {
 525                 memset(&wtime, 0, sizeof(struct rtc_time));
 526                 rtc_get_rtc_time(&wtime);
 527                 break;
 528         }
 529         case RTC_SET_TIME:      /* Set the RTC */
 530         {
 531                 struct rtc_time rtc_tm;
 532                 unsigned char mon, day, hrs, min, sec, leap_yr;
 533                 unsigned char save_control, save_freq_select;
 534                 unsigned int yrs;
 535 #ifdef CONFIG_MACH_DECSTATION
 536                 unsigned int real_yrs;
 537 #endif
 538 
 539                 if (!capable(CAP_SYS_TIME))
 540                         return -EACCES;
 541 
 542                 if (copy_from_user(&rtc_tm, (struct rtc_time __user *)arg,
 543                                    sizeof(struct rtc_time)))
 544                         return -EFAULT;
 545 
 546                 yrs = rtc_tm.tm_year + 1900;
 547                 mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
 548                 day = rtc_tm.tm_mday;
 549                 hrs = rtc_tm.tm_hour;
 550                 min = rtc_tm.tm_min;
 551                 sec = rtc_tm.tm_sec;
 552 
 553                 if (yrs < 1970)
 554                         return -EINVAL;
 555 
 556                 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
 557 
 558                 if ((mon > 12) || (day == 0))
 559                         return -EINVAL;
 560 
 561                 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
 562                         return -EINVAL;
 563 
 564                 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
 565                         return -EINVAL;
 566 
 567                 yrs -= epoch;
 568                 if (yrs > 255)          /* They are unsigned */
 569                         return -EINVAL;
 570 
 571                 spin_lock_irq(&rtc_lock);
 572 #ifdef CONFIG_MACH_DECSTATION
 573                 real_yrs = yrs;
 574                 yrs = 72;
 575 
 576                 /*
 577                  * We want to keep the year set to 73 until March
 578                  * for non-leap years, so that Feb, 29th is handled
 579                  * correctly.
 580                  */
 581                 if (!leap_yr && mon < 3) {
 582                         real_yrs--;
 583                         yrs = 73;
 584                 }
 585 #endif
 586                 /* These limits and adjustments are independent of
 587                  * whether the chip is in binary mode or not.
 588                  */
 589                 if (yrs > 169) {
 590                         spin_unlock_irq(&rtc_lock);
 591                         return -EINVAL;
 592                 }
 593                 if (yrs >= 100)
 594                         yrs -= 100;
 595 
 596                 if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
 597                     || RTC_ALWAYS_BCD) {
 598                         sec = bin2bcd(sec);
 599                         min = bin2bcd(min);
 600                         hrs = bin2bcd(hrs);
 601                         day = bin2bcd(day);
 602                         mon = bin2bcd(mon);
 603                         yrs = bin2bcd(yrs);
 604                 }
 605 
 606                 save_control = CMOS_READ(RTC_CONTROL);
 607                 CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
 608                 save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
 609                 CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
 610 
 611 #ifdef CONFIG_MACH_DECSTATION
 612                 CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
 613 #endif
 614                 CMOS_WRITE(yrs, RTC_YEAR);
 615                 CMOS_WRITE(mon, RTC_MONTH);
 616                 CMOS_WRITE(day, RTC_DAY_OF_MONTH);
 617                 CMOS_WRITE(hrs, RTC_HOURS);
 618                 CMOS_WRITE(min, RTC_MINUTES);
 619                 CMOS_WRITE(sec, RTC_SECONDS);
 620 
 621                 CMOS_WRITE(save_control, RTC_CONTROL);
 622                 CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
 623 
 624                 spin_unlock_irq(&rtc_lock);
 625                 return 0;
 626         }
 627 #ifdef RTC_IRQ
 628         case RTC_IRQP_READ:     /* Read the periodic IRQ rate.  */
 629         {
 630                 return put_user(rtc_freq, (unsigned long __user *)arg);
 631         }
 632         case RTC_IRQP_SET:      /* Set periodic IRQ rate.       */
 633         {
 634                 int tmp = 0;
 635                 unsigned char val;
 636                 /* can be called from isr via rtc_control() */
 637                 unsigned long flags;
 638 
 639                 /*
 640                  * The max we can do is 8192Hz.
 641                  */
 642                 if ((arg < 2) || (arg > 8192))
 643                         return -EINVAL;
 644                 /*
 645                  * We don't really want Joe User generating more
 646                  * than 64Hz of interrupts on a multi-user machine.
 647                  */
 648                 if (!kernel && (arg > rtc_max_user_freq) &&
 649                                         !capable(CAP_SYS_RESOURCE))
 650                         return -EACCES;
 651 
 652                 while (arg > (1<<tmp))
 653                         tmp++;
 654 
 655                 /*
 656                  * Check that the input was really a power of 2.
 657                  */
 658                 if (arg != (1<<tmp))
 659                         return -EINVAL;
 660 
 661                 rtc_freq = arg;
 662 
 663                 spin_lock_irqsave(&rtc_lock, flags);
 664                 if (hpet_set_periodic_freq(arg)) {
 665                         spin_unlock_irqrestore(&rtc_lock, flags);
 666                         return 0;
 667                 }
 668 
 669                 val = CMOS_READ(RTC_FREQ_SELECT) & 0xf0;
 670                 val |= (16 - tmp);
 671                 CMOS_WRITE(val, RTC_FREQ_SELECT);
 672                 spin_unlock_irqrestore(&rtc_lock, flags);
 673                 return 0;
 674         }
 675 #endif
 676         case RTC_EPOCH_READ:    /* Read the epoch.      */
 677         {
 678                 return put_user(epoch, (unsigned long __user *)arg);
 679         }
 680         case RTC_EPOCH_SET:     /* Set the epoch.       */
 681         {
 682                 /*
 683                  * There were no RTC clocks before 1900.
 684                  */
 685                 if (arg < 1900)
 686                         return -EINVAL;
 687 
 688                 if (!capable(CAP_SYS_TIME))
 689                         return -EACCES;
 690 
 691                 epoch = arg;
 692                 return 0;
 693         }
 694         default:
 695                 return -ENOTTY;
 696         }
 697         return copy_to_user((void __user *)arg,
 698                             &wtime, sizeof wtime) ? -EFAULT : 0;
 699 }
 700 
 701 static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 702 {
 703         long ret;
 704         ret = rtc_do_ioctl(cmd, arg, 0);
 705         return ret;
 706 }
 707 
 708 /*
 709  *      We enforce only one user at a time here with the open/close.
 710  *      Also clear the previous interrupt data on an open, and clean
 711  *      up things on a close.
 712  */
 713 static int rtc_open(struct inode *inode, struct file *file)
 714 {
 715         spin_lock_irq(&rtc_lock);
 716 
 717         if (rtc_status & RTC_IS_OPEN)
 718                 goto out_busy;
 719 
 720         rtc_status |= RTC_IS_OPEN;
 721 
 722         rtc_irq_data = 0;
 723         spin_unlock_irq(&rtc_lock);
 724         return 0;
 725 
 726 out_busy:
 727         spin_unlock_irq(&rtc_lock);
 728         return -EBUSY;
 729 }
 730 
 731 static int rtc_fasync(int fd, struct file *filp, int on)
 732 {
 733         return fasync_helper(fd, filp, on, &rtc_async_queue);
 734 }
 735 
 736 static int rtc_release(struct inode *inode, struct file *file)
 737 {
 738 #ifdef RTC_IRQ
 739         unsigned char tmp;
 740 
 741         if (rtc_has_irq == 0)
 742                 goto no_irq;
 743 
 744         /*
 745          * Turn off all interrupts once the device is no longer
 746          * in use, and clear the data.
 747          */
 748 
 749         spin_lock_irq(&rtc_lock);
 750         if (!hpet_mask_rtc_irq_bit(RTC_PIE | RTC_AIE | RTC_UIE)) {
 751                 tmp = CMOS_READ(RTC_CONTROL);
 752                 tmp &=  ~RTC_PIE;
 753                 tmp &=  ~RTC_AIE;
 754                 tmp &=  ~RTC_UIE;
 755                 CMOS_WRITE(tmp, RTC_CONTROL);
 756                 CMOS_READ(RTC_INTR_FLAGS);
 757         }
 758         if (rtc_status & RTC_TIMER_ON) {
 759                 rtc_status &= ~RTC_TIMER_ON;
 760                 del_timer(&rtc_irq_timer);
 761         }
 762         spin_unlock_irq(&rtc_lock);
 763 
 764 no_irq:
 765 #endif
 766 
 767         spin_lock_irq(&rtc_lock);
 768         rtc_irq_data = 0;
 769         rtc_status &= ~RTC_IS_OPEN;
 770         spin_unlock_irq(&rtc_lock);
 771 
 772         return 0;
 773 }
 774 
 775 #ifdef RTC_IRQ
 776 static __poll_t rtc_poll(struct file *file, poll_table *wait)
 777 {
 778         unsigned long l;
 779 
 780         if (rtc_has_irq == 0)
 781                 return 0;
 782 
 783         poll_wait(file, &rtc_wait, wait);
 784 
 785         spin_lock_irq(&rtc_lock);
 786         l = rtc_irq_data;
 787         spin_unlock_irq(&rtc_lock);
 788 
 789         if (l != 0)
 790                 return EPOLLIN | EPOLLRDNORM;
 791         return 0;
 792 }
 793 #endif
 794 
 795 /*
 796  *      The various file operations we support.
 797  */
 798 
 799 static const struct file_operations rtc_fops = {
 800         .owner          = THIS_MODULE,
 801         .llseek         = no_llseek,
 802         .read           = rtc_read,
 803 #ifdef RTC_IRQ
 804         .poll           = rtc_poll,
 805 #endif
 806         .unlocked_ioctl = rtc_ioctl,
 807         .open           = rtc_open,
 808         .release        = rtc_release,
 809         .fasync         = rtc_fasync,
 810 };
 811 
 812 static struct miscdevice rtc_dev = {
 813         .minor          = RTC_MINOR,
 814         .name           = "rtc",
 815         .fops           = &rtc_fops,
 816 };
 817 
 818 static resource_size_t rtc_size;
 819 
 820 static struct resource * __init rtc_request_region(resource_size_t size)
 821 {
 822         struct resource *r;
 823 
 824         if (RTC_IOMAPPED)
 825                 r = request_region(RTC_PORT(0), size, "rtc");
 826         else
 827                 r = request_mem_region(RTC_PORT(0), size, "rtc");
 828 
 829         if (r)
 830                 rtc_size = size;
 831 
 832         return r;
 833 }
 834 
 835 static void rtc_release_region(void)
 836 {
 837         if (RTC_IOMAPPED)
 838                 release_region(RTC_PORT(0), rtc_size);
 839         else
 840                 release_mem_region(RTC_PORT(0), rtc_size);
 841 }
 842 
 843 static int __init rtc_init(void)
 844 {
 845 #ifdef CONFIG_PROC_FS
 846         struct proc_dir_entry *ent;
 847 #endif
 848 #if defined(__alpha__) || defined(__mips__)
 849         unsigned int year, ctrl;
 850         char *guess = NULL;
 851 #endif
 852 #ifdef CONFIG_SPARC32
 853         struct device_node *ebus_dp;
 854         struct platform_device *op;
 855 #else
 856         void *r;
 857 #ifdef RTC_IRQ
 858         irq_handler_t rtc_int_handler_ptr;
 859 #endif
 860 #endif
 861 
 862 #ifdef CONFIG_SPARC32
 863         for_each_node_by_name(ebus_dp, "ebus") {
 864                 struct device_node *dp;
 865                 for_each_child_of_node(ebus_dp, dp) {
 866                         if (of_node_name_eq(dp, "rtc")) {
 867                                 op = of_find_device_by_node(dp);
 868                                 if (op) {
 869                                         rtc_port = op->resource[0].start;
 870                                         rtc_irq = op->irqs[0];
 871                                         goto found;
 872                                 }
 873                         }
 874                 }
 875         }
 876         rtc_has_irq = 0;
 877         printk(KERN_ERR "rtc_init: no PC rtc found\n");
 878         return -EIO;
 879 
 880 found:
 881         if (!rtc_irq) {
 882                 rtc_has_irq = 0;
 883                 goto no_irq;
 884         }
 885 
 886         /*
 887          * XXX Interrupt pin #7 in Espresso is shared between RTC and
 888          * PCI Slot 2 INTA# (and some INTx# in Slot 1).
 889          */
 890         if (request_irq(rtc_irq, rtc_interrupt, IRQF_SHARED, "rtc",
 891                         (void *)&rtc_port)) {
 892                 rtc_has_irq = 0;
 893                 printk(KERN_ERR "rtc: cannot register IRQ %d\n", rtc_irq);
 894                 return -EIO;
 895         }
 896 no_irq:
 897 #else
 898         r = rtc_request_region(RTC_IO_EXTENT);
 899 
 900         /*
 901          * If we've already requested a smaller range (for example, because
 902          * PNPBIOS or ACPI told us how the device is configured), the request
 903          * above might fail because it's too big.
 904          *
 905          * If so, request just the range we actually use.
 906          */
 907         if (!r)
 908                 r = rtc_request_region(RTC_IO_EXTENT_USED);
 909         if (!r) {
 910 #ifdef RTC_IRQ
 911                 rtc_has_irq = 0;
 912 #endif
 913                 printk(KERN_ERR "rtc: I/O resource %lx is not free.\n",
 914                        (long)(RTC_PORT(0)));
 915                 return -EIO;
 916         }
 917 
 918 #ifdef RTC_IRQ
 919         if (is_hpet_enabled()) {
 920                 int err;
 921 
 922                 rtc_int_handler_ptr = hpet_rtc_interrupt;
 923                 err = hpet_register_irq_handler(rtc_interrupt);
 924                 if (err != 0) {
 925                         printk(KERN_WARNING "hpet_register_irq_handler failed "
 926                                         "in rtc_init().");
 927                         return err;
 928                 }
 929         } else {
 930                 rtc_int_handler_ptr = rtc_interrupt;
 931         }
 932 
 933         if (request_irq(RTC_IRQ, rtc_int_handler_ptr, 0, "rtc", NULL)) {
 934                 /* Yeah right, seeing as irq 8 doesn't even hit the bus. */
 935                 rtc_has_irq = 0;
 936                 printk(KERN_ERR "rtc: IRQ %d is not free.\n", RTC_IRQ);
 937                 rtc_release_region();
 938 
 939                 return -EIO;
 940         }
 941         hpet_rtc_timer_init();
 942 
 943 #endif
 944 
 945 #endif /* CONFIG_SPARC32 vs. others */
 946 
 947         if (misc_register(&rtc_dev)) {
 948 #ifdef RTC_IRQ
 949                 free_irq(RTC_IRQ, NULL);
 950                 hpet_unregister_irq_handler(rtc_interrupt);
 951                 rtc_has_irq = 0;
 952 #endif
 953                 rtc_release_region();
 954                 return -ENODEV;
 955         }
 956 
 957 #ifdef CONFIG_PROC_FS
 958         ent = proc_create_single("driver/rtc", 0, NULL, rtc_proc_show);
 959         if (!ent)
 960                 printk(KERN_WARNING "rtc: Failed to register with procfs.\n");
 961 #endif
 962 
 963 #if defined(__alpha__) || defined(__mips__)
 964         rtc_freq = HZ;
 965 
 966         /* Each operating system on an Alpha uses its own epoch.
 967            Let's try to guess which one we are using now. */
 968 
 969         if (rtc_is_updating() != 0)
 970                 msleep(20);
 971 
 972         spin_lock_irq(&rtc_lock);
 973         year = CMOS_READ(RTC_YEAR);
 974         ctrl = CMOS_READ(RTC_CONTROL);
 975         spin_unlock_irq(&rtc_lock);
 976 
 977         if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
 978                 year = bcd2bin(year);       /* This should never happen... */
 979 
 980         if (year < 20) {
 981                 epoch = 2000;
 982                 guess = "SRM (post-2000)";
 983         } else if (year >= 20 && year < 48) {
 984                 epoch = 1980;
 985                 guess = "ARC console";
 986         } else if (year >= 48 && year < 72) {
 987                 epoch = 1952;
 988                 guess = "Digital UNIX";
 989 #if defined(__mips__)
 990         } else if (year >= 72 && year < 74) {
 991                 epoch = 2000;
 992                 guess = "Digital DECstation";
 993 #else
 994         } else if (year >= 70) {
 995                 epoch = 1900;
 996                 guess = "Standard PC (1900)";
 997 #endif
 998         }
 999         if (guess)
1000                 printk(KERN_INFO "rtc: %s epoch (%lu) detected\n",
1001                         guess, epoch);
1002 #endif
1003 #ifdef RTC_IRQ
1004         if (rtc_has_irq == 0)
1005                 goto no_irq2;
1006 
1007         spin_lock_irq(&rtc_lock);
1008         rtc_freq = 1024;
1009         if (!hpet_set_periodic_freq(rtc_freq)) {
1010                 /*
1011                  * Initialize periodic frequency to CMOS reset default,
1012                  * which is 1024Hz
1013                  */
1014                 CMOS_WRITE(((CMOS_READ(RTC_FREQ_SELECT) & 0xF0) | 0x06),
1015                            RTC_FREQ_SELECT);
1016         }
1017         spin_unlock_irq(&rtc_lock);
1018 no_irq2:
1019 #endif
1020 
1021         (void) init_sysctl();
1022 
1023         printk(KERN_INFO "Real Time Clock Driver v" RTC_VERSION "\n");
1024 
1025         return 0;
1026 }
1027 
1028 static void __exit rtc_exit(void)
1029 {
1030         cleanup_sysctl();
1031         remove_proc_entry("driver/rtc", NULL);
1032         misc_deregister(&rtc_dev);
1033 
1034 #ifdef CONFIG_SPARC32
1035         if (rtc_has_irq)
1036                 free_irq(rtc_irq, &rtc_port);
1037 #else
1038         rtc_release_region();
1039 #ifdef RTC_IRQ
1040         if (rtc_has_irq) {
1041                 free_irq(RTC_IRQ, NULL);
1042                 hpet_unregister_irq_handler(hpet_rtc_interrupt);
1043         }
1044 #endif
1045 #endif /* CONFIG_SPARC32 */
1046 }
1047 
1048 module_init(rtc_init);
1049 module_exit(rtc_exit);
1050 
1051 #ifdef RTC_IRQ
1052 /*
1053  *      At IRQ rates >= 4096Hz, an interrupt may get lost altogether.
1054  *      (usually during an IDE disk interrupt, with IRQ unmasking off)
1055  *      Since the interrupt handler doesn't get called, the IRQ status
1056  *      byte doesn't get read, and the RTC stops generating interrupts.
1057  *      A timer is set, and will call this function if/when that happens.
1058  *      To get it out of this stalled state, we just read the status.
1059  *      At least a jiffy of interrupts (rtc_freq/HZ) will have been lost.
1060  *      (You *really* shouldn't be trying to use a non-realtime system
1061  *      for something that requires a steady > 1KHz signal anyways.)
1062  */
1063 
1064 static void rtc_dropped_irq(struct timer_list *unused)
1065 {
1066         unsigned long freq;
1067 
1068         spin_lock_irq(&rtc_lock);
1069 
1070         if (hpet_rtc_dropped_irq()) {
1071                 spin_unlock_irq(&rtc_lock);
1072                 return;
1073         }
1074 
1075         /* Just in case someone disabled the timer from behind our back... */
1076         if (rtc_status & RTC_TIMER_ON)
1077                 mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);
1078 
1079         rtc_irq_data += ((rtc_freq/HZ)<<8);
1080         rtc_irq_data &= ~0xff;
1081         rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0);     /* restart */
1082 
1083         freq = rtc_freq;
1084 
1085         spin_unlock_irq(&rtc_lock);
1086 
1087         printk_ratelimited(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n",
1088                            freq);
1089 
1090         /* Now we have new data */
1091         wake_up_interruptible(&rtc_wait);
1092 
1093         kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);
1094 }
1095 #endif
1096 
1097 #ifdef CONFIG_PROC_FS
1098 /*
1099  *      Info exported via "/proc/driver/rtc".
1100  */
1101 
1102 static int rtc_proc_show(struct seq_file *seq, void *v)
1103 {
1104 #define YN(bit) ((ctrl & bit) ? "yes" : "no")
1105 #define NY(bit) ((ctrl & bit) ? "no" : "yes")
1106         struct rtc_time tm;
1107         unsigned char batt, ctrl;
1108         unsigned long freq;
1109 
1110         spin_lock_irq(&rtc_lock);
1111         batt = CMOS_READ(RTC_VALID) & RTC_VRT;
1112         ctrl = CMOS_READ(RTC_CONTROL);
1113         freq = rtc_freq;
1114         spin_unlock_irq(&rtc_lock);
1115 
1116 
1117         rtc_get_rtc_time(&tm);
1118 
1119         /*
1120          * There is no way to tell if the luser has the RTC set for local
1121          * time or for Universal Standard Time (GMT). Probably local though.
1122          */
1123         seq_printf(seq,
1124                    "rtc_time\t: %ptRt\n"
1125                    "rtc_date\t: %ptRd\n"
1126                    "rtc_epoch\t: %04lu\n",
1127                    &tm, &tm, epoch);
1128 
1129         get_rtc_alm_time(&tm);
1130 
1131         /*
1132          * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will
1133          * match any value for that particular field. Values that are
1134          * greater than a valid time, but less than 0xc0 shouldn't appear.
1135          */
1136         seq_puts(seq, "alarm\t\t: ");
1137         if (tm.tm_hour <= 24)
1138                 seq_printf(seq, "%02d:", tm.tm_hour);
1139         else
1140                 seq_puts(seq, "**:");
1141 
1142         if (tm.tm_min <= 59)
1143                 seq_printf(seq, "%02d:", tm.tm_min);
1144         else
1145                 seq_puts(seq, "**:");
1146 
1147         if (tm.tm_sec <= 59)
1148                 seq_printf(seq, "%02d\n", tm.tm_sec);
1149         else
1150                 seq_puts(seq, "**\n");
1151 
1152         seq_printf(seq,
1153                    "DST_enable\t: %s\n"
1154                    "BCD\t\t: %s\n"
1155                    "24hr\t\t: %s\n"
1156                    "square_wave\t: %s\n"
1157                    "alarm_IRQ\t: %s\n"
1158                    "update_IRQ\t: %s\n"
1159                    "periodic_IRQ\t: %s\n"
1160                    "periodic_freq\t: %ld\n"
1161                    "batt_status\t: %s\n",
1162                    YN(RTC_DST_EN),
1163                    NY(RTC_DM_BINARY),
1164                    YN(RTC_24H),
1165                    YN(RTC_SQWE),
1166                    YN(RTC_AIE),
1167                    YN(RTC_UIE),
1168                    YN(RTC_PIE),
1169                    freq,
1170                    batt ? "okay" : "dead");
1171 
1172         return  0;
1173 #undef YN
1174 #undef NY
1175 }
1176 #endif
1177 
1178 static void rtc_get_rtc_time(struct rtc_time *rtc_tm)
1179 {
1180         unsigned long uip_watchdog = jiffies, flags;
1181         unsigned char ctrl;
1182 #ifdef CONFIG_MACH_DECSTATION
1183         unsigned int real_year;
1184 #endif
1185 
1186         /*
1187          * read RTC once any update in progress is done. The update
1188          * can take just over 2ms. We wait 20ms. There is no need to
1189          * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
1190          * If you need to know *exactly* when a second has started, enable
1191          * periodic update complete interrupts, (via ioctl) and then
1192          * immediately read /dev/rtc which will block until you get the IRQ.
1193          * Once the read clears, read the RTC time (again via ioctl). Easy.
1194          */
1195 
1196         while (rtc_is_updating() != 0 &&
1197                time_before(jiffies, uip_watchdog + 2*HZ/100))
1198                 cpu_relax();
1199 
1200         /*
1201          * Only the values that we read from the RTC are set. We leave
1202          * tm_wday, tm_yday and tm_isdst untouched. Note that while the
1203          * RTC has RTC_DAY_OF_WEEK, we should usually ignore it, as it is
1204          * only updated by the RTC when initially set to a non-zero value.
1205          */
1206         spin_lock_irqsave(&rtc_lock, flags);
1207         rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
1208         rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
1209         rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
1210         rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
1211         rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
1212         rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
1213         /* Only set from 2.6.16 onwards */
1214         rtc_tm->tm_wday = CMOS_READ(RTC_DAY_OF_WEEK);
1215 
1216 #ifdef CONFIG_MACH_DECSTATION
1217         real_year = CMOS_READ(RTC_DEC_YEAR);
1218 #endif
1219         ctrl = CMOS_READ(RTC_CONTROL);
1220         spin_unlock_irqrestore(&rtc_lock, flags);
1221 
1222         if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
1223                 rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
1224                 rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
1225                 rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
1226                 rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
1227                 rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
1228                 rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
1229                 rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday);
1230         }
1231 
1232 #ifdef CONFIG_MACH_DECSTATION
1233         rtc_tm->tm_year += real_year - 72;
1234 #endif
1235 
1236         /*
1237          * Account for differences between how the RTC uses the values
1238          * and how they are defined in a struct rtc_time;
1239          */
1240         rtc_tm->tm_year += epoch - 1900;
1241         if (rtc_tm->tm_year <= 69)
1242                 rtc_tm->tm_year += 100;
1243 
1244         rtc_tm->tm_mon--;
1245 }
1246 
1247 static void get_rtc_alm_time(struct rtc_time *alm_tm)
1248 {
1249         unsigned char ctrl;
1250 
1251         /*
1252          * Only the values that we read from the RTC are set. That
1253          * means only tm_hour, tm_min, and tm_sec.
1254          */
1255         spin_lock_irq(&rtc_lock);
1256         alm_tm->tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
1257         alm_tm->tm_min = CMOS_READ(RTC_MINUTES_ALARM);
1258         alm_tm->tm_hour = CMOS_READ(RTC_HOURS_ALARM);
1259         ctrl = CMOS_READ(RTC_CONTROL);
1260         spin_unlock_irq(&rtc_lock);
1261 
1262         if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
1263                 alm_tm->tm_sec = bcd2bin(alm_tm->tm_sec);
1264                 alm_tm->tm_min = bcd2bin(alm_tm->tm_min);
1265                 alm_tm->tm_hour = bcd2bin(alm_tm->tm_hour);
1266         }
1267 }
1268 
1269 #ifdef RTC_IRQ
1270 /*
1271  * Used to disable/enable interrupts for any one of UIE, AIE, PIE.
1272  * Rumour has it that if you frob the interrupt enable/disable
1273  * bits in RTC_CONTROL, you should read RTC_INTR_FLAGS, to
1274  * ensure you actually start getting interrupts. Probably for
1275  * compatibility with older/broken chipset RTC implementations.
1276  * We also clear out any old irq data after an ioctl() that
1277  * meddles with the interrupt enable/disable bits.
1278  */
1279 
1280 static void mask_rtc_irq_bit_locked(unsigned char bit)
1281 {
1282         unsigned char val;
1283 
1284         if (hpet_mask_rtc_irq_bit(bit))
1285                 return;
1286         val = CMOS_READ(RTC_CONTROL);
1287         val &=  ~bit;
1288         CMOS_WRITE(val, RTC_CONTROL);
1289         CMOS_READ(RTC_INTR_FLAGS);
1290 
1291         rtc_irq_data = 0;
1292 }
1293 
1294 static void set_rtc_irq_bit_locked(unsigned char bit)
1295 {
1296         unsigned char val;
1297 
1298         if (hpet_set_rtc_irq_bit(bit))
1299                 return;
1300         val = CMOS_READ(RTC_CONTROL);
1301         val |= bit;
1302         CMOS_WRITE(val, RTC_CONTROL);
1303         CMOS_READ(RTC_INTR_FLAGS);
1304 
1305         rtc_irq_data = 0;
1306 }
1307 #endif
1308 
1309 MODULE_AUTHOR("Paul Gortmaker");
1310 MODULE_LICENSE("GPL");
1311 MODULE_ALIAS_MISCDEV(RTC_MINOR);
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/char/rtc.c

DEFINITIONS
