/* * Real Time Clock interface for Linux * * Copyright (C) 1996 Paul Gortmaker * * This driver allows use of the real time clock (built into * nearly all computers) from user space. It exports the /dev/rtc * interface supporting various ioctl() and also the * /proc/driver/rtc pseudo-file for status information. * * The ioctls can be used to set the interrupt behaviour and * generation rate from the RTC via IRQ 8. Then the /dev/rtc * interface can be used to make use of these timer interrupts, * be they interval or alarm based. * * The /dev/rtc interface will block on reads until an interrupt * has been received. If a RTC interrupt has already happened, * it will output an unsigned long and then block. The output value * contains the interrupt status in the low byte and the number of * interrupts since the last read in the remaining high bytes. The * /dev/rtc interface can also be used with the select(2) call. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Based on other minimal char device drivers, like Alan's * watchdog, Ted's random, etc. etc. * * 1.07 Paul Gortmaker. * 1.08 Miquel van Smoorenburg: disallow certain things on the * DEC Alpha as the CMOS clock is also used for other things. * 1.09 Nikita Schmidt: epoch support and some Alpha cleanup. * 1.09a Pete Zaitcev: Sun SPARC * 1.09b Jeff Garzik: Modularize, init cleanup * 1.09c Jeff Garzik: SMP cleanup * 1.10 Paul Barton-Davis: add support for async I/O * 1.10a Andrea Arcangeli: Alpha updates * 1.10b Andrew Morton: SMP lock fix * 1.10c Cesar Barros: SMP locking fixes and cleanup * 1.10d Paul Gortmaker: delete paranoia check in rtc_exit * 1.10e Maciej W. Rozycki: Handle DECstation's year weirdness. */ #define RTC_VERSION "1.10e" #define RTC_IO_EXTENT 0x10 /* Only really two ports, but... */ /* * Note that *all* calls to CMOS_READ and CMOS_WRITE are done with * interrupts disabled. Due to the index-port/data-port (0x70/0x71) * design of the RTC, we don't want two different things trying to * get to it at once. (e.g. the periodic 11 min sync from time.c vs. * this driver.) */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef __sparc__ #include #ifdef __sparc_v9__ #include #endif static unsigned long rtc_port; static int rtc_irq = PCI_IRQ_NONE; #endif static int rtc_has_irq = 1; /* * We sponge a minor off of the misc major. No need slurping * up another valuable major dev number for this. If you add * an ioctl, make sure you don't conflict with SPARC's RTC * ioctls. */ static struct fasync_struct *rtc_async_queue; static DECLARE_WAIT_QUEUE_HEAD(rtc_wait); static struct timer_list rtc_irq_timer; static ssize_t rtc_read(struct file *file, char *buf, size_t count, loff_t *ppos); static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg); #if RTC_IRQ static unsigned int rtc_poll(struct file *file, poll_table *wait); #endif static void get_rtc_time (struct rtc_time *rtc_tm); static void get_rtc_alm_time (struct rtc_time *alm_tm); #if RTC_IRQ static void rtc_dropped_irq(unsigned long data); static void set_rtc_irq_bit(unsigned char bit); static void mask_rtc_irq_bit(unsigned char bit); #endif static inline unsigned char rtc_is_updating(void); static int rtc_read_proc(char *page, char **start, off_t off, int count, int *eof, void *data); /* * Bits in rtc_status. (6 bits of room for future expansion) */ #define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */ #define RTC_TIMER_ON 0x02 /* missed irq timer active */ /* * rtc_status is never changed by rtc_interrupt, and ioctl/open/close is * protected by the big kernel lock. However, ioctl can still disable the timer * in rtc_status and then with del_timer after the interrupt has read * rtc_status but before mod_timer is called, which would then reenable the * timer (but you would need to have an awful timing before you'd trip on it) */ static unsigned long rtc_status = 0; /* bitmapped status byte. */ static unsigned long rtc_freq = 0; /* Current periodic IRQ rate */ static unsigned long rtc_irq_data = 0; /* our output to the world */ /* * If this driver ever becomes modularised, it will be really nice * to make the epoch retain its value across module reload... */ static unsigned long epoch = 1900; /* year corresponding to 0x00 */ static const unsigned char days_in_mo[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; #if RTC_IRQ /* * A very tiny interrupt handler. It runs with SA_INTERRUPT set, * but there is possibility of conflicting with the set_rtc_mmss() * call (the rtc irq and the timer irq can easily run at the same * time in two different CPUs). So we need to serializes * accesses to the chip with the rtc_lock spinlock that each * architecture should implement in the timer code. * (See ./arch/XXXX/kernel/time.c for the set_rtc_mmss() function.) */ static void rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs) { /* * Can be an alarm interrupt, update complete interrupt, * or a periodic interrupt. We store the status in the * low byte and the number of interrupts received since * the last read in the remainder of rtc_irq_data. */ spin_lock (&rtc_lock); rtc_irq_data += 0x100; rtc_irq_data &= ~0xff; rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0); if (rtc_status & RTC_TIMER_ON) mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100); spin_unlock (&rtc_lock); /* Now do the rest of the actions */ wake_up_interruptible(&rtc_wait); kill_fasync (&rtc_async_queue, SIGIO, POLL_IN); } #endif /* * Now all the various file operations that we export. */ static ssize_t rtc_read(struct file *file, char *buf, size_t count, loff_t *ppos) { #if !RTC_IRQ return -EIO; #else DECLARE_WAITQUEUE(wait, current); unsigned long data; ssize_t retval; if (rtc_has_irq == 0) return -EIO; if (count < sizeof(unsigned long)) return -EINVAL; add_wait_queue(&rtc_wait, &wait); current->state = TASK_INTERRUPTIBLE; do { /* First make it right. Then make it fast. Putting this whole * block within the parentheses of a while would be too * confusing. And no, xchg() is not the answer. */ spin_lock_irq (&rtc_lock); data = rtc_irq_data; rtc_irq_data = 0; spin_unlock_irq (&rtc_lock); if (data != 0) break; if (file->f_flags & O_NONBLOCK) { retval = -EAGAIN; goto out; } if (signal_pending(current)) { retval = -ERESTARTSYS; goto out; } schedule(); } while (1); retval = put_user(data, (unsigned long *)buf); if (!retval) retval = sizeof(unsigned long); out: current->state = TASK_RUNNING; remove_wait_queue(&rtc_wait, &wait); return retval; #endif } static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { struct rtc_time wtime; #if RTC_IRQ if (rtc_has_irq == 0) { switch (cmd) { case RTC_AIE_OFF: case RTC_AIE_ON: case RTC_PIE_OFF: case RTC_PIE_ON: case RTC_UIE_OFF: case RTC_UIE_ON: case RTC_IRQP_READ: case RTC_IRQP_SET: return -EINVAL; }; } #endif switch (cmd) { #if RTC_IRQ case RTC_AIE_OFF: /* Mask alarm int. enab. bit */ { mask_rtc_irq_bit(RTC_AIE); return 0; } case RTC_AIE_ON: /* Allow alarm interrupts. */ { set_rtc_irq_bit(RTC_AIE); return 0; } case RTC_PIE_OFF: /* Mask periodic int. enab. bit */ { mask_rtc_irq_bit(RTC_PIE); if (rtc_status & RTC_TIMER_ON) { spin_lock_irq (&rtc_lock); rtc_status &= ~RTC_TIMER_ON; del_timer(&rtc_irq_timer); spin_unlock_irq (&rtc_lock); } return 0; } case RTC_PIE_ON: /* Allow periodic ints */ { /* * We don't really want Joe User enabling more * than 64Hz of interrupts on a multi-user machine. */ if ((rtc_freq > 64) && (!capable(CAP_SYS_RESOURCE))) return -EACCES; if (!(rtc_status & RTC_TIMER_ON)) { spin_lock_irq (&rtc_lock); rtc_irq_timer.expires = jiffies + HZ/rtc_freq + 2*HZ/100; add_timer(&rtc_irq_timer); rtc_status |= RTC_TIMER_ON; spin_unlock_irq (&rtc_lock); } set_rtc_irq_bit(RTC_PIE); return 0; } case RTC_UIE_OFF: /* Mask ints from RTC updates. */ { mask_rtc_irq_bit(RTC_UIE); return 0; } case RTC_UIE_ON: /* Allow ints for RTC updates. */ { set_rtc_irq_bit(RTC_UIE); return 0; } #endif case RTC_ALM_READ: /* Read the present alarm time */ { /* * This returns a struct rtc_time. Reading >= 0xc0 * means "don't care" or "match all". Only the tm_hour, * tm_min, and tm_sec values are filled in. */ get_rtc_alm_time(&wtime); break; } case RTC_ALM_SET: /* Store a time into the alarm */ { /* * This expects a struct rtc_time. Writing 0xff means * "don't care" or "match all". Only the tm_hour, * tm_min and tm_sec are used. */ unsigned char hrs, min, sec; struct rtc_time alm_tm; if (copy_from_user(&alm_tm, (struct rtc_time*)arg, sizeof(struct rtc_time))) return -EFAULT; hrs = alm_tm.tm_hour; min = alm_tm.tm_min; sec = alm_tm.tm_sec; if (hrs >= 24) hrs = 0xff; if (min >= 60) min = 0xff; if (sec >= 60) sec = 0xff; spin_lock_irq(&rtc_lock); if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { BIN_TO_BCD(sec); BIN_TO_BCD(min); BIN_TO_BCD(hrs); } CMOS_WRITE(hrs, RTC_HOURS_ALARM); CMOS_WRITE(min, RTC_MINUTES_ALARM); CMOS_WRITE(sec, RTC_SECONDS_ALARM); spin_unlock_irq(&rtc_lock); return 0; } case RTC_RD_TIME: /* Read the time/date from RTC */ { get_rtc_time(&wtime); break; } case RTC_SET_TIME: /* Set the RTC */ { struct rtc_time rtc_tm; unsigned char mon, day, hrs, min, sec, leap_yr; unsigned char save_control, save_freq_select; unsigned int yrs; #ifdef CONFIG_DECSTATION unsigned int real_yrs; #endif if (!capable(CAP_SYS_TIME)) return -EACCES; if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time))) return -EFAULT; yrs = rtc_tm.tm_year + 1900; mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */ day = rtc_tm.tm_mday; hrs = rtc_tm.tm_hour; min = rtc_tm.tm_min; sec = rtc_tm.tm_sec; if (yrs < 1970) return -EINVAL; leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400)); if ((mon > 12) || (day == 0)) return -EINVAL; if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr))) return -EINVAL; if ((hrs >= 24) || (min >= 60) || (sec >= 60)) return -EINVAL; if ((yrs -= epoch) > 255) /* They are unsigned */ return -EINVAL; spin_lock_irq(&rtc_lock); #ifdef CONFIG_DECSTATION real_yrs = yrs; yrs = 72; /* * We want to keep the year set to 73 until March * for non-leap years, so that Feb, 29th is handled * correctly. */ if (!leap_yr && mon < 3) { real_yrs--; yrs = 73; } #endif /* These limits and adjustments are independant of * whether the chip is in binary mode or not. */ if (yrs > 169) { spin_unlock_irq(&rtc_lock); return -EINVAL; } if (yrs >= 100) yrs -= 100; if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { BIN_TO_BCD(sec); BIN_TO_BCD(min); BIN_TO_BCD(hrs); BIN_TO_BCD(day); BIN_TO_BCD(mon); BIN_TO_BCD(yrs); } save_control = CMOS_READ(RTC_CONTROL); CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL); save_freq_select = CMOS_READ(RTC_FREQ_SELECT); CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT); #ifdef CONFIG_DECSTATION CMOS_WRITE(real_yrs, RTC_DEC_YEAR); #endif CMOS_WRITE(yrs, RTC_YEAR); CMOS_WRITE(mon, RTC_MONTH); CMOS_WRITE(day, RTC_DAY_OF_MONTH); CMOS_WRITE(hrs, RTC_HOURS); CMOS_WRITE(min, RTC_MINUTES); CMOS_WRITE(sec, RTC_SECONDS); CMOS_WRITE(save_control, RTC_CONTROL); CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT); spin_unlock_irq(&rtc_lock); return 0; } #if RTC_IRQ case RTC_IRQP_READ: /* Read the periodic IRQ rate. */ { return put_user(rtc_freq, (unsigned long *)arg); } case RTC_IRQP_SET: /* Set periodic IRQ rate. */ { int tmp = 0; unsigned char val; /* * The max we can do is 8192Hz. */ if ((arg < 2) || (arg > 8192)) return -EINVAL; /* * We don't really want Joe User generating more * than 64Hz of interrupts on a multi-user machine. */ if ((arg > 64) && (!capable(CAP_SYS_RESOURCE))) return -EACCES; while (arg > (1<f_flags & FASYNC) { rtc_fasync (-1, file, 0); } no_irq: #endif spin_lock_irq (&rtc_lock); rtc_irq_data = 0; spin_unlock_irq (&rtc_lock); /* No need for locking -- nobody else can do anything until this rmw is * committed, and no timer is running. */ rtc_status &= ~RTC_IS_OPEN; return 0; } #if RTC_IRQ /* Called without the kernel lock - fine */ static unsigned int rtc_poll(struct file *file, poll_table *wait) { unsigned long l; if (rtc_has_irq == 0) return 0; poll_wait(file, &rtc_wait, wait); spin_lock_irq (&rtc_lock); l = rtc_irq_data; spin_unlock_irq (&rtc_lock); if (l != 0) return POLLIN | POLLRDNORM; return 0; } #endif /* * The various file operations we support. */ static struct file_operations rtc_fops = { owner: THIS_MODULE, llseek: no_llseek, read: rtc_read, #if RTC_IRQ poll: rtc_poll, #endif ioctl: rtc_ioctl, open: rtc_open, release: rtc_release, fasync: rtc_fasync, }; static struct miscdevice rtc_dev= { RTC_MINOR, "rtc", &rtc_fops }; static int __init rtc_init(void) { #if defined(__alpha__) || defined(__mips__) unsigned int year, ctrl; unsigned long uip_watchdog; char *guess = NULL; #endif #ifdef __sparc__ struct linux_ebus *ebus; struct linux_ebus_device *edev; #ifdef __sparc_v9__ struct isa_bridge *isa_br; struct isa_device *isa_dev; #endif #endif #ifdef __sparc__ for_each_ebus(ebus) { for_each_ebusdev(edev, ebus) { if(strcmp(edev->prom_name, "rtc") == 0) { rtc_port = edev->resource[0].start; rtc_irq = edev->irqs[0]; goto found; } } } #ifdef __sparc_v9__ for_each_isa(isa_br) { for_each_isadev(isa_dev, isa_br) { if (strcmp(isa_dev->prom_name, "rtc") == 0) { rtc_port = isa_dev->resource.start; rtc_irq = isa_dev->irq; goto found; } } } #endif printk(KERN_ERR "rtc_init: no PC rtc found\n"); return -EIO; found: if (rtc_irq == PCI_IRQ_NONE) { rtc_has_irq = 0; goto no_irq; } /* * XXX Interrupt pin #7 in Espresso is shared between RTC and * PCI Slot 2 INTA# (and some INTx# in Slot 1). SA_INTERRUPT here * is asking for trouble with add-on boards. Change to SA_SHIRQ. */ if (request_irq(rtc_irq, rtc_interrupt, SA_INTERRUPT, "rtc", (void *)&rtc_port)) { /* * Standard way for sparc to print irq's is to use * __irq_itoa(). I think for EBus it's ok to use %d. */ printk(KERN_ERR "rtc: cannot register IRQ %d\n", rtc_irq); return -EIO; } no_irq: #else if (check_region (RTC_PORT (0), RTC_IO_EXTENT)) { printk(KERN_ERR "rtc: I/O port %d is not free.\n", RTC_PORT (0)); return -EIO; } #if RTC_IRQ if(request_irq(RTC_IRQ, rtc_interrupt, SA_INTERRUPT, "rtc", NULL)) { /* Yeah right, seeing as irq 8 doesn't even hit the bus. */ printk(KERN_ERR "rtc: IRQ %d is not free.\n", RTC_IRQ); return -EIO; } #endif request_region(RTC_PORT(0), RTC_IO_EXTENT, "rtc"); #endif /* __sparc__ vs. others */ misc_register(&rtc_dev); create_proc_read_entry ("driver/rtc", 0, 0, rtc_read_proc, NULL); #if defined(__alpha__) || defined(__mips__) rtc_freq = HZ; /* Each operating system on an Alpha uses its own epoch. Let's try to guess which one we are using now. */ uip_watchdog = jiffies; if (rtc_is_updating() != 0) while (jiffies - uip_watchdog < 2*HZ/100) { barrier(); cpu_relax(); } spin_lock_irq(&rtc_lock); year = CMOS_READ(RTC_YEAR); ctrl = CMOS_READ(RTC_CONTROL); spin_unlock_irq(&rtc_lock); if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) BCD_TO_BIN(year); /* This should never happen... */ if (year < 20) { epoch = 2000; guess = "SRM (post-2000)"; } else if (year >= 20 && year < 48) { epoch = 1980; guess = "ARC console"; } else if (year >= 48 && year < 72) { epoch = 1952; guess = "Digital UNIX"; #if defined(__mips__) } else if (year >= 72 && year < 74) { epoch = 2000; guess = "Digital DECstation"; #else } else if (year >= 70) { epoch = 1900; guess = "Standard PC (1900)"; #endif } if (guess) printk(KERN_INFO "rtc: %s epoch (%lu) detected\n", guess, epoch); #endif #if RTC_IRQ if (rtc_has_irq == 0) goto no_irq2; init_timer(&rtc_irq_timer); rtc_irq_timer.function = rtc_dropped_irq; spin_lock_irq(&rtc_lock); /* Initialize periodic freq. to CMOS reset default, which is 1024Hz */ CMOS_WRITE(((CMOS_READ(RTC_FREQ_SELECT) & 0xF0) | 0x06), RTC_FREQ_SELECT); spin_unlock_irq(&rtc_lock); rtc_freq = 1024; no_irq2: #endif printk(KERN_INFO "Real Time Clock Driver v" RTC_VERSION "\n"); return 0; } static void __exit rtc_exit (void) { remove_proc_entry ("driver/rtc", NULL); misc_deregister(&rtc_dev); #ifdef __sparc__ if (rtc_has_irq) free_irq (rtc_irq, &rtc_port); #else release_region (RTC_PORT (0), RTC_IO_EXTENT); #if RTC_IRQ if (rtc_has_irq) free_irq (RTC_IRQ, NULL); #endif #endif /* __sparc__ */ } module_init(rtc_init); module_exit(rtc_exit); EXPORT_NO_SYMBOLS; #if RTC_IRQ /* * At IRQ rates >= 4096Hz, an interrupt may get lost altogether. * (usually during an IDE disk interrupt, with IRQ unmasking off) * Since the interrupt handler doesn't get called, the IRQ status * byte doesn't get read, and the RTC stops generating interrupts. * A timer is set, and will call this function if/when that happens. * To get it out of this stalled state, we just read the status. * At least a jiffy of interrupts (rtc_freq/HZ) will have been lost. * (You *really* shouldn't be trying to use a non-realtime system * for something that requires a steady > 1KHz signal anyways.) */ static void rtc_dropped_irq(unsigned long data) { unsigned long freq; spin_lock_irq (&rtc_lock); /* Just in case someone disabled the timer from behind our back... */ if (rtc_status & RTC_TIMER_ON) mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100); rtc_irq_data += ((rtc_freq/HZ)<<8); rtc_irq_data &= ~0xff; rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0); /* restart */ freq = rtc_freq; spin_unlock_irq(&rtc_lock); printk(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n", freq); /* Now we have new data */ wake_up_interruptible(&rtc_wait); kill_fasync (&rtc_async_queue, SIGIO, POLL_IN); } #endif /* * Info exported via "/proc/driver/rtc". */ static int rtc_proc_output (char *buf) { #define YN(bit) ((ctrl & bit) ? "yes" : "no") #define NY(bit) ((ctrl & bit) ? "no" : "yes") char *p; struct rtc_time tm; unsigned char batt, ctrl; unsigned long freq; spin_lock_irq(&rtc_lock); batt = CMOS_READ(RTC_VALID) & RTC_VRT; ctrl = CMOS_READ(RTC_CONTROL); freq = rtc_freq; spin_unlock_irq(&rtc_lock); p = buf; get_rtc_time(&tm); /* * There is no way to tell if the luser has the RTC set for local * time or for Universal Standard Time (GMT). Probably local though. */ p += sprintf(p, "rtc_time\t: %02d:%02d:%02d\n" "rtc_date\t: %04d-%02d-%02d\n" "rtc_epoch\t: %04lu\n", tm.tm_hour, tm.tm_min, tm.tm_sec, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch); get_rtc_alm_time(&tm); /* * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will * match any value for that particular field. Values that are * greater than a valid time, but less than 0xc0 shouldn't appear. */ p += sprintf(p, "alarm\t\t: "); if (tm.tm_hour <= 24) p += sprintf(p, "%02d:", tm.tm_hour); else p += sprintf(p, "**:"); if (tm.tm_min <= 59) p += sprintf(p, "%02d:", tm.tm_min); else p += sprintf(p, "**:"); if (tm.tm_sec <= 59) p += sprintf(p, "%02d\n", tm.tm_sec); else p += sprintf(p, "**\n"); p += sprintf(p, "DST_enable\t: %s\n" "BCD\t\t: %s\n" "24hr\t\t: %s\n" "square_wave\t: %s\n" "alarm_IRQ\t: %s\n" "update_IRQ\t: %s\n" "periodic_IRQ\t: %s\n" "periodic_freq\t: %ld\n" "batt_status\t: %s\n", YN(RTC_DST_EN), NY(RTC_DM_BINARY), YN(RTC_24H), YN(RTC_SQWE), YN(RTC_AIE), YN(RTC_UIE), YN(RTC_PIE), freq, batt ? "okay" : "dead"); return p - buf; #undef YN #undef NY } static int rtc_read_proc(char *page, char **start, off_t off, int count, int *eof, void *data) { int len = rtc_proc_output (page); if (len <= off+count) *eof = 1; *start = page + off; len -= off; if (len>count) len = count; if (len<0) len = 0; return len; } /* * Returns true if a clock update is in progress */ /* FIXME shouldn't this be above rtc_init to make it fully inlined? */ static inline unsigned char rtc_is_updating(void) { unsigned char uip; spin_lock_irq(&rtc_lock); uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP); spin_unlock_irq(&rtc_lock); return uip; } static void get_rtc_time(struct rtc_time *rtc_tm) { unsigned long uip_watchdog = jiffies; unsigned char ctrl; #ifdef CONFIG_DECSTATION unsigned int real_year; #endif /* * read RTC once any update in progress is done. The update * can take just over 2ms. We wait 10 to 20ms. There is no need to * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP. * If you need to know *exactly* when a second has started, enable * periodic update complete interrupts, (via ioctl) and then * immediately read /dev/rtc which will block until you get the IRQ. * Once the read clears, read the RTC time (again via ioctl). Easy. */ if (rtc_is_updating() != 0) while (jiffies - uip_watchdog < 2*HZ/100) { barrier(); cpu_relax(); } /* * Only the values that we read from the RTC are set. We leave * tm_wday, tm_yday and tm_isdst untouched. Even though the * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated * by the RTC when initially set to a non-zero value. */ spin_lock_irq(&rtc_lock); rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS); rtc_tm->tm_min = CMOS_READ(RTC_MINUTES); rtc_tm->tm_hour = CMOS_READ(RTC_HOURS); rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH); rtc_tm->tm_mon = CMOS_READ(RTC_MONTH); rtc_tm->tm_year = CMOS_READ(RTC_YEAR); #ifdef CONFIG_DECSTATION real_year = CMOS_READ(RTC_DEC_YEAR); #endif ctrl = CMOS_READ(RTC_CONTROL); spin_unlock_irq(&rtc_lock); if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { BCD_TO_BIN(rtc_tm->tm_sec); BCD_TO_BIN(rtc_tm->tm_min); BCD_TO_BIN(rtc_tm->tm_hour); BCD_TO_BIN(rtc_tm->tm_mday); BCD_TO_BIN(rtc_tm->tm_mon); BCD_TO_BIN(rtc_tm->tm_year); } #ifdef CONFIG_DECSTATION rtc_tm->tm_year += real_year - 72; #endif /* * Account for differences between how the RTC uses the values * and how they are defined in a struct rtc_time; */ if ((rtc_tm->tm_year += (epoch - 1900)) <= 69) rtc_tm->tm_year += 100; rtc_tm->tm_mon--; } static void get_rtc_alm_time(struct rtc_time *alm_tm) { unsigned char ctrl; /* * Only the values that we read from the RTC are set. That * means only tm_hour, tm_min, and tm_sec. */ spin_lock_irq(&rtc_lock); alm_tm->tm_sec = CMOS_READ(RTC_SECONDS_ALARM); alm_tm->tm_min = CMOS_READ(RTC_MINUTES_ALARM); alm_tm->tm_hour = CMOS_READ(RTC_HOURS_ALARM); ctrl = CMOS_READ(RTC_CONTROL); spin_unlock_irq(&rtc_lock); if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { BCD_TO_BIN(alm_tm->tm_sec); BCD_TO_BIN(alm_tm->tm_min); BCD_TO_BIN(alm_tm->tm_hour); } } #if RTC_IRQ /* * Used to disable/enable interrupts for any one of UIE, AIE, PIE. * Rumour has it that if you frob the interrupt enable/disable * bits in RTC_CONTROL, you should read RTC_INTR_FLAGS, to * ensure you actually start getting interrupts. Probably for * compatibility with older/broken chipset RTC implementations. * We also clear out any old irq data after an ioctl() that * meddles with the interrupt enable/disable bits. */ static void mask_rtc_irq_bit(unsigned char bit) { unsigned char val; spin_lock_irq(&rtc_lock); val = CMOS_READ(RTC_CONTROL); val &= ~bit; CMOS_WRITE(val, RTC_CONTROL); CMOS_READ(RTC_INTR_FLAGS); rtc_irq_data = 0; spin_unlock_irq(&rtc_lock); } static void set_rtc_irq_bit(unsigned char bit) { unsigned char val; spin_lock_irq(&rtc_lock); val = CMOS_READ(RTC_CONTROL); val |= bit; CMOS_WRITE(val, RTC_CONTROL); CMOS_READ(RTC_INTR_FLAGS); rtc_irq_data = 0; spin_unlock_irq(&rtc_lock); } #endif MODULE_AUTHOR("Paul Gortmaker"); MODULE_LICENSE("GPL");