rtc.c revision 5fd1fe9c582e00ca0a98f852cd693dc3caf607a0
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 */ 52 53#define RTC_VERSION "1.12ac" 54 55/* 56 * Note that *all* calls to CMOS_READ and CMOS_WRITE are done with 57 * interrupts disabled. Due to the index-port/data-port (0x70/0x71) 58 * design of the RTC, we don't want two different things trying to 59 * get to it at once. (e.g. the periodic 11 min sync from time.c vs. 60 * this driver.) 61 */ 62 63#include <linux/interrupt.h> 64#include <linux/module.h> 65#include <linux/kernel.h> 66#include <linux/types.h> 67#include <linux/miscdevice.h> 68#include <linux/ioport.h> 69#include <linux/fcntl.h> 70#include <linux/mc146818rtc.h> 71#include <linux/init.h> 72#include <linux/poll.h> 73#include <linux/proc_fs.h> 74#include <linux/seq_file.h> 75#include <linux/spinlock.h> 76#include <linux/sysctl.h> 77#include <linux/wait.h> 78#include <linux/bcd.h> 79#include <linux/delay.h> 80 81#include <asm/current.h> 82#include <asm/uaccess.h> 83#include <asm/system.h> 84 85#ifdef CONFIG_X86 86#include <asm/hpet.h> 87#endif 88 89#ifdef CONFIG_SPARC32 90#include <linux/pci.h> 91#include <asm/ebus.h> 92 93static unsigned long rtc_port; 94static int rtc_irq = PCI_IRQ_NONE; 95#endif 96 97#ifdef CONFIG_HPET_RTC_IRQ 98#undef RTC_IRQ 99#endif 100 101#ifdef RTC_IRQ 102static int rtc_has_irq = 1; 103#endif 104 105#ifndef CONFIG_HPET_EMULATE_RTC 106#define is_hpet_enabled() 0 107#define hpet_set_alarm_time(hrs, min, sec) 0 108#define hpet_set_periodic_freq(arg) 0 109#define hpet_mask_rtc_irq_bit(arg) 0 110#define hpet_set_rtc_irq_bit(arg) 0 111#define hpet_rtc_timer_init() do { } while (0) 112#define hpet_rtc_dropped_irq() 0 113#ifdef RTC_IRQ 114static irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id) 115{ 116 return 0; 117} 118#endif 119#else 120extern irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id); 121#endif 122 123/* 124 * We sponge a minor off of the misc major. No need slurping 125 * up another valuable major dev number for this. If you add 126 * an ioctl, make sure you don't conflict with SPARC's RTC 127 * ioctls. 128 */ 129 130static struct fasync_struct *rtc_async_queue; 131 132static DECLARE_WAIT_QUEUE_HEAD(rtc_wait); 133 134#ifdef RTC_IRQ 135static void rtc_dropped_irq(unsigned long data); 136 137static DEFINE_TIMER(rtc_irq_timer, rtc_dropped_irq, 0, 0); 138#endif 139 140static ssize_t rtc_read(struct file *file, char __user *buf, 141 size_t count, loff_t *ppos); 142 143static int rtc_ioctl(struct inode *inode, struct file *file, 144 unsigned int cmd, unsigned long arg); 145 146#ifdef RTC_IRQ 147static unsigned int rtc_poll(struct file *file, poll_table *wait); 148#endif 149 150static void get_rtc_alm_time(struct rtc_time *alm_tm); 151#ifdef RTC_IRQ 152static void set_rtc_irq_bit_locked(unsigned char bit); 153static void mask_rtc_irq_bit_locked(unsigned char bit); 154 155static inline void set_rtc_irq_bit(unsigned char bit) 156{ 157 spin_lock_irq(&rtc_lock); 158 set_rtc_irq_bit_locked(bit); 159 spin_unlock_irq(&rtc_lock); 160} 161 162static void mask_rtc_irq_bit(unsigned char bit) 163{ 164 spin_lock_irq(&rtc_lock); 165 mask_rtc_irq_bit_locked(bit); 166 spin_unlock_irq(&rtc_lock); 167} 168#endif 169 170#ifdef CONFIG_PROC_FS 171static int rtc_proc_open(struct inode *inode, struct file *file); 172#endif 173 174/* 175 * Bits in rtc_status. (6 bits of room for future expansion) 176 */ 177 178#define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */ 179#define RTC_TIMER_ON 0x02 /* missed irq timer active */ 180 181/* 182 * rtc_status is never changed by rtc_interrupt, and ioctl/open/close is 183 * protected by the big kernel lock. However, ioctl can still disable the timer 184 * in rtc_status and then with del_timer after the interrupt has read 185 * rtc_status but before mod_timer is called, which would then reenable the 186 * timer (but you would need to have an awful timing before you'd trip on it) 187 */ 188static unsigned long rtc_status; /* bitmapped status byte. */ 189static unsigned long rtc_freq; /* Current periodic IRQ rate */ 190static unsigned long rtc_irq_data; /* our output to the world */ 191static unsigned long rtc_max_user_freq = 64; /* > this, need CAP_SYS_RESOURCE */ 192 193#ifdef RTC_IRQ 194/* 195 * rtc_task_lock nests inside rtc_lock. 196 */ 197static DEFINE_SPINLOCK(rtc_task_lock); 198static rtc_task_t *rtc_callback; 199#endif 200 201/* 202 * If this driver ever becomes modularised, it will be really nice 203 * to make the epoch retain its value across module reload... 204 */ 205 206static unsigned long epoch = 1900; /* year corresponding to 0x00 */ 207 208static const unsigned char days_in_mo[] = 209{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; 210 211/* 212 * Returns true if a clock update is in progress 213 */ 214static inline unsigned char rtc_is_updating(void) 215{ 216 unsigned long flags; 217 unsigned char uip; 218 219 spin_lock_irqsave(&rtc_lock, flags); 220 uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP); 221 spin_unlock_irqrestore(&rtc_lock, flags); 222 return uip; 223} 224 225#ifdef RTC_IRQ 226/* 227 * A very tiny interrupt handler. It runs with IRQF_DISABLED set, 228 * but there is possibility of conflicting with the set_rtc_mmss() 229 * call (the rtc irq and the timer irq can easily run at the same 230 * time in two different CPUs). So we need to serialize 231 * accesses to the chip with the rtc_lock spinlock that each 232 * architecture should implement in the timer code. 233 * (See ./arch/XXXX/kernel/time.c for the set_rtc_mmss() function.) 234 */ 235 236irqreturn_t rtc_interrupt(int irq, void *dev_id) 237{ 238 /* 239 * Can be an alarm interrupt, update complete interrupt, 240 * or a periodic interrupt. We store the status in the 241 * low byte and the number of interrupts received since 242 * the last read in the remainder of rtc_irq_data. 243 */ 244 245 spin_lock(&rtc_lock); 246 rtc_irq_data += 0x100; 247 rtc_irq_data &= ~0xff; 248 if (is_hpet_enabled()) { 249 /* 250 * In this case it is HPET RTC interrupt handler 251 * calling us, with the interrupt information 252 * passed as arg1, instead of irq. 253 */ 254 rtc_irq_data |= (unsigned long)irq & 0xF0; 255 } else { 256 rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0); 257 } 258 259 if (rtc_status & RTC_TIMER_ON) 260 mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100); 261 262 spin_unlock(&rtc_lock); 263 264 /* Now do the rest of the actions */ 265 spin_lock(&rtc_task_lock); 266 if (rtc_callback) 267 rtc_callback->func(rtc_callback->private_data); 268 spin_unlock(&rtc_task_lock); 269 wake_up_interruptible(&rtc_wait); 270 271 kill_fasync(&rtc_async_queue, SIGIO, POLL_IN); 272 273 return IRQ_HANDLED; 274} 275#endif 276 277/* 278 * sysctl-tuning infrastructure. 279 */ 280static ctl_table rtc_table[] = { 281 { 282 .ctl_name = CTL_UNNUMBERED, 283 .procname = "max-user-freq", 284 .data = &rtc_max_user_freq, 285 .maxlen = sizeof(int), 286 .mode = 0644, 287 .proc_handler = &proc_dointvec, 288 }, 289 { .ctl_name = 0 } 290}; 291 292static ctl_table rtc_root[] = { 293 { 294 .ctl_name = CTL_UNNUMBERED, 295 .procname = "rtc", 296 .mode = 0555, 297 .child = rtc_table, 298 }, 299 { .ctl_name = 0 } 300}; 301 302static ctl_table dev_root[] = { 303 { 304 .ctl_name = CTL_DEV, 305 .procname = "dev", 306 .mode = 0555, 307 .child = rtc_root, 308 }, 309 { .ctl_name = 0 } 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 BIN_TO_BCD(sec); 520 else 521 sec = 0xff; 522 523 if (min < 60) 524 BIN_TO_BCD(min); 525 else 526 min = 0xff; 527 528 if (hrs < 24) 529 BIN_TO_BCD(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 BIN_TO_BCD(sec); 616 BIN_TO_BCD(min); 617 BIN_TO_BCD(hrs); 618 BIN_TO_BCD(day); 619 BIN_TO_BCD(mon); 620 BIN_TO_BCD(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 spin_lock_irqsave(&rtc_lock, flags); 679 if (hpet_set_periodic_freq(arg)) { 680 spin_unlock_irqrestore(&rtc_lock, flags); 681 return 0; 682 } 683 rtc_freq = arg; 684 685 val = CMOS_READ(RTC_FREQ_SELECT) & 0xf0; 686 val |= (16 - tmp); 687 CMOS_WRITE(val, RTC_FREQ_SELECT); 688 spin_unlock_irqrestore(&rtc_lock, flags); 689 return 0; 690 } 691#endif 692 case RTC_EPOCH_READ: /* Read the epoch. */ 693 { 694 return put_user(epoch, (unsigned long __user *)arg); 695 } 696 case RTC_EPOCH_SET: /* Set the epoch. */ 697 { 698 /* 699 * There were no RTC clocks before 1900. 700 */ 701 if (arg < 1900) 702 return -EINVAL; 703 704 if (!capable(CAP_SYS_TIME)) 705 return -EACCES; 706 707 epoch = arg; 708 return 0; 709 } 710 default: 711 return -ENOTTY; 712 } 713 return copy_to_user((void __user *)arg, 714 &wtime, sizeof wtime) ? -EFAULT : 0; 715} 716 717static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, 718 unsigned long arg) 719{ 720 return rtc_do_ioctl(cmd, arg, 0); 721} 722 723/* 724 * We enforce only one user at a time here with the open/close. 725 * Also clear the previous interrupt data on an open, and clean 726 * up things on a close. 727 */ 728 729/* We use rtc_lock to protect against concurrent opens. So the BKL is not 730 * needed here. Or anywhere else in this driver. */ 731static int rtc_open(struct inode *inode, struct file *file) 732{ 733 spin_lock_irq(&rtc_lock); 734 735 if (rtc_status & RTC_IS_OPEN) 736 goto out_busy; 737 738 rtc_status |= RTC_IS_OPEN; 739 740 rtc_irq_data = 0; 741 spin_unlock_irq(&rtc_lock); 742 return 0; 743 744out_busy: 745 spin_unlock_irq(&rtc_lock); 746 return -EBUSY; 747} 748 749static int rtc_fasync(int fd, struct file *filp, int on) 750{ 751 return fasync_helper(fd, filp, on, &rtc_async_queue); 752} 753 754static int rtc_release(struct inode *inode, struct file *file) 755{ 756#ifdef RTC_IRQ 757 unsigned char tmp; 758 759 if (rtc_has_irq == 0) 760 goto no_irq; 761 762 /* 763 * Turn off all interrupts once the device is no longer 764 * in use, and clear the data. 765 */ 766 767 spin_lock_irq(&rtc_lock); 768 if (!hpet_mask_rtc_irq_bit(RTC_PIE | RTC_AIE | RTC_UIE)) { 769 tmp = CMOS_READ(RTC_CONTROL); 770 tmp &= ~RTC_PIE; 771 tmp &= ~RTC_AIE; 772 tmp &= ~RTC_UIE; 773 CMOS_WRITE(tmp, RTC_CONTROL); 774 CMOS_READ(RTC_INTR_FLAGS); 775 } 776 if (rtc_status & RTC_TIMER_ON) { 777 rtc_status &= ~RTC_TIMER_ON; 778 del_timer(&rtc_irq_timer); 779 } 780 spin_unlock_irq(&rtc_lock); 781 782 if (file->f_flags & FASYNC) 783 rtc_fasync(-1, file, 0); 784no_irq: 785#endif 786 787 spin_lock_irq(&rtc_lock); 788 rtc_irq_data = 0; 789 rtc_status &= ~RTC_IS_OPEN; 790 spin_unlock_irq(&rtc_lock); 791 792 return 0; 793} 794 795#ifdef RTC_IRQ 796/* Called without the kernel lock - fine */ 797static unsigned int rtc_poll(struct file *file, poll_table *wait) 798{ 799 unsigned long l; 800 801 if (rtc_has_irq == 0) 802 return 0; 803 804 poll_wait(file, &rtc_wait, wait); 805 806 spin_lock_irq(&rtc_lock); 807 l = rtc_irq_data; 808 spin_unlock_irq(&rtc_lock); 809 810 if (l != 0) 811 return POLLIN | POLLRDNORM; 812 return 0; 813} 814#endif 815 816int rtc_register(rtc_task_t *task) 817{ 818#ifndef RTC_IRQ 819 return -EIO; 820#else 821 if (task == NULL || task->func == NULL) 822 return -EINVAL; 823 spin_lock_irq(&rtc_lock); 824 if (rtc_status & RTC_IS_OPEN) { 825 spin_unlock_irq(&rtc_lock); 826 return -EBUSY; 827 } 828 spin_lock(&rtc_task_lock); 829 if (rtc_callback) { 830 spin_unlock(&rtc_task_lock); 831 spin_unlock_irq(&rtc_lock); 832 return -EBUSY; 833 } 834 rtc_status |= RTC_IS_OPEN; 835 rtc_callback = task; 836 spin_unlock(&rtc_task_lock); 837 spin_unlock_irq(&rtc_lock); 838 return 0; 839#endif 840} 841EXPORT_SYMBOL(rtc_register); 842 843int rtc_unregister(rtc_task_t *task) 844{ 845#ifndef RTC_IRQ 846 return -EIO; 847#else 848 unsigned char tmp; 849 850 spin_lock_irq(&rtc_lock); 851 spin_lock(&rtc_task_lock); 852 if (rtc_callback != task) { 853 spin_unlock(&rtc_task_lock); 854 spin_unlock_irq(&rtc_lock); 855 return -ENXIO; 856 } 857 rtc_callback = NULL; 858 859 /* disable controls */ 860 if (!hpet_mask_rtc_irq_bit(RTC_PIE | RTC_AIE | RTC_UIE)) { 861 tmp = CMOS_READ(RTC_CONTROL); 862 tmp &= ~RTC_PIE; 863 tmp &= ~RTC_AIE; 864 tmp &= ~RTC_UIE; 865 CMOS_WRITE(tmp, RTC_CONTROL); 866 CMOS_READ(RTC_INTR_FLAGS); 867 } 868 if (rtc_status & RTC_TIMER_ON) { 869 rtc_status &= ~RTC_TIMER_ON; 870 del_timer(&rtc_irq_timer); 871 } 872 rtc_status &= ~RTC_IS_OPEN; 873 spin_unlock(&rtc_task_lock); 874 spin_unlock_irq(&rtc_lock); 875 return 0; 876#endif 877} 878EXPORT_SYMBOL(rtc_unregister); 879 880int rtc_control(rtc_task_t *task, unsigned int cmd, unsigned long arg) 881{ 882#ifndef RTC_IRQ 883 return -EIO; 884#else 885 unsigned long flags; 886 if (cmd != RTC_PIE_ON && cmd != RTC_PIE_OFF && cmd != RTC_IRQP_SET) 887 return -EINVAL; 888 spin_lock_irqsave(&rtc_task_lock, flags); 889 if (rtc_callback != task) { 890 spin_unlock_irqrestore(&rtc_task_lock, flags); 891 return -ENXIO; 892 } 893 spin_unlock_irqrestore(&rtc_task_lock, flags); 894 return rtc_do_ioctl(cmd, arg, 1); 895#endif 896} 897EXPORT_SYMBOL(rtc_control); 898 899/* 900 * The various file operations we support. 901 */ 902 903static const struct file_operations rtc_fops = { 904 .owner = THIS_MODULE, 905 .llseek = no_llseek, 906 .read = rtc_read, 907#ifdef RTC_IRQ 908 .poll = rtc_poll, 909#endif 910 .ioctl = rtc_ioctl, 911 .open = rtc_open, 912 .release = rtc_release, 913 .fasync = rtc_fasync, 914}; 915 916static struct miscdevice rtc_dev = { 917 .minor = RTC_MINOR, 918 .name = "rtc", 919 .fops = &rtc_fops, 920}; 921 922#ifdef CONFIG_PROC_FS 923static const struct file_operations rtc_proc_fops = { 924 .owner = THIS_MODULE, 925 .open = rtc_proc_open, 926 .read = seq_read, 927 .llseek = seq_lseek, 928 .release = single_release, 929}; 930#endif 931 932static resource_size_t rtc_size; 933 934static struct resource * __init rtc_request_region(resource_size_t size) 935{ 936 struct resource *r; 937 938 if (RTC_IOMAPPED) 939 r = request_region(RTC_PORT(0), size, "rtc"); 940 else 941 r = request_mem_region(RTC_PORT(0), size, "rtc"); 942 943 if (r) 944 rtc_size = size; 945 946 return r; 947} 948 949static void rtc_release_region(void) 950{ 951 if (RTC_IOMAPPED) 952 release_region(RTC_PORT(0), rtc_size); 953 else 954 release_mem_region(RTC_PORT(0), rtc_size); 955} 956 957static int __init rtc_init(void) 958{ 959#ifdef CONFIG_PROC_FS 960 struct proc_dir_entry *ent; 961#endif 962#if defined(__alpha__) || defined(__mips__) 963 unsigned int year, ctrl; 964 char *guess = NULL; 965#endif 966#ifdef CONFIG_SPARC32 967 struct linux_ebus *ebus; 968 struct linux_ebus_device *edev; 969#else 970 void *r; 971#ifdef RTC_IRQ 972 irq_handler_t rtc_int_handler_ptr; 973#endif 974#endif 975 976#ifdef CONFIG_SPARC32 977 for_each_ebus(ebus) { 978 for_each_ebusdev(edev, ebus) { 979 if (strcmp(edev->prom_node->name, "rtc") == 0) { 980 rtc_port = edev->resource[0].start; 981 rtc_irq = edev->irqs[0]; 982 goto found; 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 == PCI_IRQ_NONE) { 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 rtc_int_handler_ptr = hpet_rtc_interrupt; 1031 } else { 1032 rtc_int_handler_ptr = rtc_interrupt; 1033 } 1034 1035 if (request_irq(RTC_IRQ, rtc_int_handler_ptr, IRQF_DISABLED, 1036 "rtc", NULL)) { 1037 /* Yeah right, seeing as irq 8 doesn't even hit the bus. */ 1038 rtc_has_irq = 0; 1039 printk(KERN_ERR "rtc: IRQ %d is not free.\n", RTC_IRQ); 1040 rtc_release_region(); 1041 1042 return -EIO; 1043 } 1044 hpet_rtc_timer_init(); 1045 1046#endif 1047 1048#endif /* CONFIG_SPARC32 vs. others */ 1049 1050 if (misc_register(&rtc_dev)) { 1051#ifdef RTC_IRQ 1052 free_irq(RTC_IRQ, NULL); 1053 rtc_has_irq = 0; 1054#endif 1055 rtc_release_region(); 1056 return -ENODEV; 1057 } 1058 1059#ifdef CONFIG_PROC_FS 1060 ent = create_proc_entry("driver/rtc", 0, NULL); 1061 if (ent) 1062 ent->proc_fops = &rtc_proc_fops; 1063 else 1064 printk(KERN_WARNING "rtc: Failed to register with procfs.\n"); 1065#endif 1066 1067#if defined(__alpha__) || defined(__mips__) 1068 rtc_freq = HZ; 1069 1070 /* Each operating system on an Alpha uses its own epoch. 1071 Let's try to guess which one we are using now. */ 1072 1073 if (rtc_is_updating() != 0) 1074 msleep(20); 1075 1076 spin_lock_irq(&rtc_lock); 1077 year = CMOS_READ(RTC_YEAR); 1078 ctrl = CMOS_READ(RTC_CONTROL); 1079 spin_unlock_irq(&rtc_lock); 1080 1081 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) 1082 BCD_TO_BIN(year); /* This should never happen... */ 1083 1084 if (year < 20) { 1085 epoch = 2000; 1086 guess = "SRM (post-2000)"; 1087 } else if (year >= 20 && year < 48) { 1088 epoch = 1980; 1089 guess = "ARC console"; 1090 } else if (year >= 48 && year < 72) { 1091 epoch = 1952; 1092 guess = "Digital UNIX"; 1093#if defined(__mips__) 1094 } else if (year >= 72 && year < 74) { 1095 epoch = 2000; 1096 guess = "Digital DECstation"; 1097#else 1098 } else if (year >= 70) { 1099 epoch = 1900; 1100 guess = "Standard PC (1900)"; 1101#endif 1102 } 1103 if (guess) 1104 printk(KERN_INFO "rtc: %s epoch (%lu) detected\n", 1105 guess, epoch); 1106#endif 1107#ifdef RTC_IRQ 1108 if (rtc_has_irq == 0) 1109 goto no_irq2; 1110 1111 spin_lock_irq(&rtc_lock); 1112 rtc_freq = 1024; 1113 if (!hpet_set_periodic_freq(rtc_freq)) { 1114 /* 1115 * Initialize periodic frequency to CMOS reset default, 1116 * which is 1024Hz 1117 */ 1118 CMOS_WRITE(((CMOS_READ(RTC_FREQ_SELECT) & 0xF0) | 0x06), 1119 RTC_FREQ_SELECT); 1120 } 1121 spin_unlock_irq(&rtc_lock); 1122no_irq2: 1123#endif 1124 1125 (void) init_sysctl(); 1126 1127 printk(KERN_INFO "Real Time Clock Driver v" RTC_VERSION "\n"); 1128 1129 return 0; 1130} 1131 1132static void __exit rtc_exit(void) 1133{ 1134 cleanup_sysctl(); 1135 remove_proc_entry("driver/rtc", NULL); 1136 misc_deregister(&rtc_dev); 1137 1138#ifdef CONFIG_SPARC32 1139 if (rtc_has_irq) 1140 free_irq(rtc_irq, &rtc_port); 1141#else 1142 rtc_release_region(); 1143#ifdef RTC_IRQ 1144 if (rtc_has_irq) 1145 free_irq(RTC_IRQ, NULL); 1146#endif 1147#endif /* CONFIG_SPARC32 */ 1148} 1149 1150module_init(rtc_init); 1151module_exit(rtc_exit); 1152 1153#ifdef RTC_IRQ 1154/* 1155 * At IRQ rates >= 4096Hz, an interrupt may get lost altogether. 1156 * (usually during an IDE disk interrupt, with IRQ unmasking off) 1157 * Since the interrupt handler doesn't get called, the IRQ status 1158 * byte doesn't get read, and the RTC stops generating interrupts. 1159 * A timer is set, and will call this function if/when that happens. 1160 * To get it out of this stalled state, we just read the status. 1161 * At least a jiffy of interrupts (rtc_freq/HZ) will have been lost. 1162 * (You *really* shouldn't be trying to use a non-realtime system 1163 * for something that requires a steady > 1KHz signal anyways.) 1164 */ 1165 1166static void rtc_dropped_irq(unsigned long data) 1167{ 1168 unsigned long freq; 1169 1170 spin_lock_irq(&rtc_lock); 1171 1172 if (hpet_rtc_dropped_irq()) { 1173 spin_unlock_irq(&rtc_lock); 1174 return; 1175 } 1176 1177 /* Just in case someone disabled the timer from behind our back... */ 1178 if (rtc_status & RTC_TIMER_ON) 1179 mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100); 1180 1181 rtc_irq_data += ((rtc_freq/HZ)<<8); 1182 rtc_irq_data &= ~0xff; 1183 rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0); /* restart */ 1184 1185 freq = rtc_freq; 1186 1187 spin_unlock_irq(&rtc_lock); 1188 1189 if (printk_ratelimit()) { 1190 printk(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n", 1191 freq); 1192 } 1193 1194 /* Now we have new data */ 1195 wake_up_interruptible(&rtc_wait); 1196 1197 kill_fasync(&rtc_async_queue, SIGIO, POLL_IN); 1198} 1199#endif 1200 1201#ifdef CONFIG_PROC_FS 1202/* 1203 * Info exported via "/proc/driver/rtc". 1204 */ 1205 1206static int rtc_proc_show(struct seq_file *seq, void *v) 1207{ 1208#define YN(bit) ((ctrl & bit) ? "yes" : "no") 1209#define NY(bit) ((ctrl & bit) ? "no" : "yes") 1210 struct rtc_time tm; 1211 unsigned char batt, ctrl; 1212 unsigned long freq; 1213 1214 spin_lock_irq(&rtc_lock); 1215 batt = CMOS_READ(RTC_VALID) & RTC_VRT; 1216 ctrl = CMOS_READ(RTC_CONTROL); 1217 freq = rtc_freq; 1218 spin_unlock_irq(&rtc_lock); 1219 1220 1221 rtc_get_rtc_time(&tm); 1222 1223 /* 1224 * There is no way to tell if the luser has the RTC set for local 1225 * time or for Universal Standard Time (GMT). Probably local though. 1226 */ 1227 seq_printf(seq, 1228 "rtc_time\t: %02d:%02d:%02d\n" 1229 "rtc_date\t: %04d-%02d-%02d\n" 1230 "rtc_epoch\t: %04lu\n", 1231 tm.tm_hour, tm.tm_min, tm.tm_sec, 1232 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch); 1233 1234 get_rtc_alm_time(&tm); 1235 1236 /* 1237 * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will 1238 * match any value for that particular field. Values that are 1239 * greater than a valid time, but less than 0xc0 shouldn't appear. 1240 */ 1241 seq_puts(seq, "alarm\t\t: "); 1242 if (tm.tm_hour <= 24) 1243 seq_printf(seq, "%02d:", tm.tm_hour); 1244 else 1245 seq_puts(seq, "**:"); 1246 1247 if (tm.tm_min <= 59) 1248 seq_printf(seq, "%02d:", tm.tm_min); 1249 else 1250 seq_puts(seq, "**:"); 1251 1252 if (tm.tm_sec <= 59) 1253 seq_printf(seq, "%02d\n", tm.tm_sec); 1254 else 1255 seq_puts(seq, "**\n"); 1256 1257 seq_printf(seq, 1258 "DST_enable\t: %s\n" 1259 "BCD\t\t: %s\n" 1260 "24hr\t\t: %s\n" 1261 "square_wave\t: %s\n" 1262 "alarm_IRQ\t: %s\n" 1263 "update_IRQ\t: %s\n" 1264 "periodic_IRQ\t: %s\n" 1265 "periodic_freq\t: %ld\n" 1266 "batt_status\t: %s\n", 1267 YN(RTC_DST_EN), 1268 NY(RTC_DM_BINARY), 1269 YN(RTC_24H), 1270 YN(RTC_SQWE), 1271 YN(RTC_AIE), 1272 YN(RTC_UIE), 1273 YN(RTC_PIE), 1274 freq, 1275 batt ? "okay" : "dead"); 1276 1277 return 0; 1278#undef YN 1279#undef NY 1280} 1281 1282static int rtc_proc_open(struct inode *inode, struct file *file) 1283{ 1284 return single_open(file, rtc_proc_show, NULL); 1285} 1286#endif 1287 1288void rtc_get_rtc_time(struct rtc_time *rtc_tm) 1289{ 1290 unsigned long uip_watchdog = jiffies, flags; 1291 unsigned char ctrl; 1292#ifdef CONFIG_MACH_DECSTATION 1293 unsigned int real_year; 1294#endif 1295 1296 /* 1297 * read RTC once any update in progress is done. The update 1298 * can take just over 2ms. We wait 20ms. There is no need to 1299 * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP. 1300 * If you need to know *exactly* when a second has started, enable 1301 * periodic update complete interrupts, (via ioctl) and then 1302 * immediately read /dev/rtc which will block until you get the IRQ. 1303 * Once the read clears, read the RTC time (again via ioctl). Easy. 1304 */ 1305 1306 while (rtc_is_updating() != 0 && jiffies - uip_watchdog < 2*HZ/100) 1307 cpu_relax(); 1308 1309 /* 1310 * Only the values that we read from the RTC are set. We leave 1311 * tm_wday, tm_yday and tm_isdst untouched. Note that while the 1312 * RTC has RTC_DAY_OF_WEEK, we should usually ignore it, as it is 1313 * only updated by the RTC when initially set to a non-zero value. 1314 */ 1315 spin_lock_irqsave(&rtc_lock, flags); 1316 rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS); 1317 rtc_tm->tm_min = CMOS_READ(RTC_MINUTES); 1318 rtc_tm->tm_hour = CMOS_READ(RTC_HOURS); 1319 rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH); 1320 rtc_tm->tm_mon = CMOS_READ(RTC_MONTH); 1321 rtc_tm->tm_year = CMOS_READ(RTC_YEAR); 1322 /* Only set from 2.6.16 onwards */ 1323 rtc_tm->tm_wday = CMOS_READ(RTC_DAY_OF_WEEK); 1324 1325#ifdef CONFIG_MACH_DECSTATION 1326 real_year = CMOS_READ(RTC_DEC_YEAR); 1327#endif 1328 ctrl = CMOS_READ(RTC_CONTROL); 1329 spin_unlock_irqrestore(&rtc_lock, flags); 1330 1331 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { 1332 BCD_TO_BIN(rtc_tm->tm_sec); 1333 BCD_TO_BIN(rtc_tm->tm_min); 1334 BCD_TO_BIN(rtc_tm->tm_hour); 1335 BCD_TO_BIN(rtc_tm->tm_mday); 1336 BCD_TO_BIN(rtc_tm->tm_mon); 1337 BCD_TO_BIN(rtc_tm->tm_year); 1338 BCD_TO_BIN(rtc_tm->tm_wday); 1339 } 1340 1341#ifdef CONFIG_MACH_DECSTATION 1342 rtc_tm->tm_year += real_year - 72; 1343#endif 1344 1345 /* 1346 * Account for differences between how the RTC uses the values 1347 * and how they are defined in a struct rtc_time; 1348 */ 1349 rtc_tm->tm_year += epoch - 1900; 1350 if (rtc_tm->tm_year <= 69) 1351 rtc_tm->tm_year += 100; 1352 1353 rtc_tm->tm_mon--; 1354} 1355 1356static void get_rtc_alm_time(struct rtc_time *alm_tm) 1357{ 1358 unsigned char ctrl; 1359 1360 /* 1361 * Only the values that we read from the RTC are set. That 1362 * means only tm_hour, tm_min, and tm_sec. 1363 */ 1364 spin_lock_irq(&rtc_lock); 1365 alm_tm->tm_sec = CMOS_READ(RTC_SECONDS_ALARM); 1366 alm_tm->tm_min = CMOS_READ(RTC_MINUTES_ALARM); 1367 alm_tm->tm_hour = CMOS_READ(RTC_HOURS_ALARM); 1368 ctrl = CMOS_READ(RTC_CONTROL); 1369 spin_unlock_irq(&rtc_lock); 1370 1371 if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { 1372 BCD_TO_BIN(alm_tm->tm_sec); 1373 BCD_TO_BIN(alm_tm->tm_min); 1374 BCD_TO_BIN(alm_tm->tm_hour); 1375 } 1376} 1377 1378#ifdef RTC_IRQ 1379/* 1380 * Used to disable/enable interrupts for any one of UIE, AIE, PIE. 1381 * Rumour has it that if you frob the interrupt enable/disable 1382 * bits in RTC_CONTROL, you should read RTC_INTR_FLAGS, to 1383 * ensure you actually start getting interrupts. Probably for 1384 * compatibility with older/broken chipset RTC implementations. 1385 * We also clear out any old irq data after an ioctl() that 1386 * meddles with the interrupt enable/disable bits. 1387 */ 1388 1389static void mask_rtc_irq_bit_locked(unsigned char bit) 1390{ 1391 unsigned char val; 1392 1393 if (hpet_mask_rtc_irq_bit(bit)) 1394 return; 1395 val = CMOS_READ(RTC_CONTROL); 1396 val &= ~bit; 1397 CMOS_WRITE(val, RTC_CONTROL); 1398 CMOS_READ(RTC_INTR_FLAGS); 1399 1400 rtc_irq_data = 0; 1401} 1402 1403static void set_rtc_irq_bit_locked(unsigned char bit) 1404{ 1405 unsigned char val; 1406 1407 if (hpet_set_rtc_irq_bit(bit)) 1408 return; 1409 val = CMOS_READ(RTC_CONTROL); 1410 val |= bit; 1411 CMOS_WRITE(val, RTC_CONTROL); 1412 CMOS_READ(RTC_INTR_FLAGS); 1413 1414 rtc_irq_data = 0; 1415} 1416#endif 1417 1418MODULE_AUTHOR("Paul Gortmaker"); 1419MODULE_LICENSE("GPL"); 1420MODULE_ALIAS_MISCDEV(RTC_MINOR); 1421