/* $Id: ds1286.c,v 1.5 1999/06/24 01:00:50 ulfc Exp $ * * Real Time Clock interface for Linux * * Copyright (C) 1998, 1999 Ralf Baechle * * Based on code written by 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/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. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define DS1286_VERSION "1.0" /* * 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 DECLARE_WAIT_QUEUE_HEAD(ds1286_wait); static long long ds1286_llseek(struct file *file, loff_t offset, int origin); static ssize_t ds1286_read(struct file *file, char *buf, size_t count, loff_t *ppos); static int ds1286_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg); static unsigned int ds1286_poll(struct file *file, poll_table *wait); void get_rtc_time (struct rtc_time *rtc_tm); void get_rtc_alm_time (struct rtc_time *alm_tm); void set_rtc_irq_bit(unsigned char bit); void clear_rtc_irq_bit(unsigned char bit); static inline unsigned char ds1286_is_updating(void); static spinlock_t ds1286_lock = SPIN_LOCK_UNLOCKED; /* * Bits in rtc_status. (7 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 */ unsigned char ds1286_status = 0; /* bitmapped status byte. */ unsigned long ds1286_freq = 0; /* Current periodic IRQ rate */ unsigned long ds1286_irq_data = 0; /* our output to the world */ unsigned char days_in_mo[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; /* * A very tiny interrupt handler. It runs with SA_INTERRUPT set, * so that there is no possibility of conflicting with the * set_rtc_mmss() call that happens during some timer interrupts. * (See ./arch/XXXX/kernel/time.c for the set_rtc_mmss() function.) */ /* * Now all the various file operations that we export. */ static long long ds1286_llseek(struct file *file, loff_t offset, int origin) { return -ESPIPE; } static ssize_t ds1286_read(struct file *file, char *buf, size_t count, loff_t *ppos) { DECLARE_WAITQUEUE(wait, current); unsigned long data; ssize_t retval; if (count < sizeof(unsigned long)) return -EINVAL; add_wait_queue(&ds1286_wait, &wait); current->state = TASK_INTERRUPTIBLE; while ((data = xchg(&ds1286_irq_data, 0)) == 0) { if (file->f_flags & O_NONBLOCK) { retval = -EAGAIN; goto out; } if (signal_pending(current)) { retval = -ERESTARTSYS; goto out; } schedule(); } retval = put_user(data, (unsigned long *)buf); if (!retval) retval = sizeof(unsigned long); out: current->state = TASK_RUNNING; remove_wait_queue(&ds1286_wait, &wait); return retval; } static int ds1286_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { struct rtc_time wtime; switch (cmd) { case RTC_AIE_OFF: /* Mask alarm int. enab. bit */ { unsigned int flags; unsigned char val; if (!capable(CAP_SYS_TIME)) return -EACCES; spin_lock_irqsave(&ds1286_lock, flags); val = CMOS_READ(RTC_CMD); val |= RTC_TDM; CMOS_WRITE(val, RTC_CMD); spin_unlock_irqrestore(&ds1286_lock, flags); return 0; } case RTC_AIE_ON: /* Allow alarm interrupts. */ { unsigned int flags; unsigned char val; if (!capable(CAP_SYS_TIME)) return -EACCES; spin_lock_irqsave(&ds1286_lock, flags); val = CMOS_READ(RTC_CMD); val &= ~RTC_TDM; CMOS_WRITE(val, RTC_CMD); spin_unlock_irqrestore(&ds1286_lock, flags); return 0; } case RTC_WIE_OFF: /* Mask watchdog int. enab. bit */ { unsigned int flags; unsigned char val; if (!capable(CAP_SYS_TIME)) return -EACCES; spin_lock_irqsave(&ds1286_lock, flags); val = CMOS_READ(RTC_CMD); val |= RTC_WAM; CMOS_WRITE(val, RTC_CMD); spin_unlock_irqrestore(&ds1286_lock, flags); return 0; } case RTC_WIE_ON: /* Allow watchdog interrupts. */ { unsigned int flags; unsigned char val; if (!capable(CAP_SYS_TIME)) return -EACCES; spin_lock_irqsave(&ds1286_lock, flags); val = CMOS_READ(RTC_CMD); val &= ~RTC_WAM; CMOS_WRITE(val, RTC_CMD); spin_unlock_irqrestore(&ds1286_lock, flags); return 0; } 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 (!capable(CAP_SYS_TIME)) return -EACCES; 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; if (hrs >= 24) hrs = 0xff; if (min >= 60) min = 0xff; BIN_TO_BCD(sec); BIN_TO_BCD(min); BIN_TO_BCD(hrs); spin_lock(&ds1286_lock); CMOS_WRITE(hrs, RTC_HOURS_ALARM); CMOS_WRITE(min, RTC_MINUTES_ALARM); spin_unlock(&ds1286_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; unsigned int yrs, flags; 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 -= 1940) > 255) /* They are unsigned */ return -EINVAL; if (yrs >= 100) yrs -= 100; BIN_TO_BCD(sec); BIN_TO_BCD(min); BIN_TO_BCD(hrs); BIN_TO_BCD(day); BIN_TO_BCD(mon); BIN_TO_BCD(yrs); spin_lock_irqsave(&ds1286_lock, flags); save_control = CMOS_READ(RTC_CMD); CMOS_WRITE((save_control|RTC_TE), RTC_CMD); CMOS_WRITE(yrs, RTC_YEAR); CMOS_WRITE(mon, RTC_MONTH); CMOS_WRITE(day, RTC_DATE); CMOS_WRITE(hrs, RTC_HOURS); CMOS_WRITE(min, RTC_MINUTES); CMOS_WRITE(sec, RTC_SECONDS); CMOS_WRITE(0, RTC_HUNDREDTH_SECOND); CMOS_WRITE(save_control, RTC_CMD); spin_unlock_irqrestore(&ds1286_lock, flags); return 0; } default: return -EINVAL; } return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0; } /* * We enforce only one user at a time here with the open/close. * Also clear the previous interrupt data on an open, and clean * up things on a close. */ static int ds1286_open(struct inode *inode, struct file *file) { if(ds1286_status & RTC_IS_OPEN) return -EBUSY; ds1286_status |= RTC_IS_OPEN; ds1286_irq_data = 0; return 0; } static int ds1286_release(struct inode *inode, struct file *file) { ds1286_status &= ~RTC_IS_OPEN; return 0; } static unsigned int ds1286_poll(struct file *file, poll_table *wait) { poll_wait(file, &ds1286_wait, wait); if (ds1286_irq_data != 0) return POLLIN | POLLRDNORM; return 0; } /* * The various file operations we support. */ static struct file_operations ds1286_fops = { ds1286_llseek, ds1286_read, NULL, /* No write */ NULL, /* No readdir */ ds1286_poll, ds1286_ioctl, NULL, /* No mmap */ ds1286_open, NULL, ds1286_release }; static struct miscdevice ds1286_dev= { RTC_MINOR, "rtc", &ds1286_fops }; int __init ds1286_init(void) { printk(KERN_INFO "DS1286 Real Time Clock Driver v%s\n", DS1286_VERSION); misc_register(&ds1286_dev); return 0; } static char *days[] = { "***", "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" }; /* * Info exported via "/proc/rtc". */ int get_ds1286_status(char *buf) { char *p, *s; struct rtc_time tm; unsigned char hundredth, month, cmd, amode; p = buf; get_rtc_time(&tm); hundredth = CMOS_READ(RTC_HUNDREDTH_SECOND); hundredth = BCD_TO_BIN(hundredth); p += sprintf(p, "rtc_time\t: %02d:%02d:%02d.%02d\n" "rtc_date\t: %04d-%02d-%02d\n", tm.tm_hour, tm.tm_min, tm.tm_sec, hundredth, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday); /* * 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. */ get_rtc_alm_time(&tm); p += sprintf(p, "alarm\t\t: %s ", days[tm.tm_wday]); 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\n", tm.tm_min); else p += sprintf(p, "**\n"); month = CMOS_READ(RTC_MONTH); p += sprintf(p, "oscillator\t: %s\n" "square_wave\t: %s\n", (month & RTC_EOSC) ? "disabled" : "enabled", (month & RTC_ESQW) ? "disabled" : "enabled"); amode = ((CMOS_READ(RTC_MINUTES_ALARM) & 0x80) >> 5) | ((CMOS_READ(RTC_HOURS_ALARM) & 0x80) >> 6) | ((CMOS_READ(RTC_DAY_ALARM) & 0x80) >> 7); if (amode == 7) s = "each minute"; else if (amode == 3) s = "minutes match"; else if (amode == 1) s = "hours and minutes match"; else if (amode == 0) s = "days, hours and minutes match"; else s = "invalid"; p += sprintf(p, "alarm_mode\t: %s\n", s); cmd = CMOS_READ(RTC_CMD); p += sprintf(p, "alarm_enable\t: %s\n" "wdog_alarm\t: %s\n" "alarm_mask\t: %s\n" "wdog_alarm_mask\t: %s\n" "interrupt_mode\t: %s\n" "INTB_mode\t: %s_active\n" "interrupt_pins\t: %s\n", (cmd & RTC_TDF) ? "yes" : "no", (cmd & RTC_WAF) ? "yes" : "no", (cmd & RTC_TDM) ? "disabled" : "enabled", (cmd & RTC_WAM) ? "disabled" : "enabled", (cmd & RTC_PU_LVL) ? "pulse" : "level", (cmd & RTC_IBH_LO) ? "low" : "high", (cmd & RTC_IPSW) ? "unswapped" : "swapped"); return p - buf; } /* * Returns true if a clock update is in progress */ static inline unsigned char ds1286_is_updating(void) { return CMOS_READ(RTC_CMD) & RTC_TE; } void get_rtc_time(struct rtc_time *rtc_tm) { unsigned long uip_watchdog = jiffies; unsigned char save_control; unsigned int flags; /* * 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 (ds1286_is_updating() != 0) while (jiffies - uip_watchdog < 2*HZ/100) barrier(); /* * 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_irqsave(&ds1286_lock, flags); save_control = CMOS_READ(RTC_CMD); CMOS_WRITE((save_control|RTC_TE), RTC_CMD); rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS); rtc_tm->tm_min = CMOS_READ(RTC_MINUTES); rtc_tm->tm_hour = CMOS_READ(RTC_HOURS) & 0x1f; rtc_tm->tm_mday = CMOS_READ(RTC_DATE); rtc_tm->tm_mon = CMOS_READ(RTC_MONTH) & 0x1f; rtc_tm->tm_year = CMOS_READ(RTC_YEAR); CMOS_WRITE(save_control, RTC_CMD); spin_unlock_irqrestore(&ds1286_lock, flags); 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); /* * 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 < 45) rtc_tm->tm_year += 30; if ((rtc_tm->tm_year += 40) < 70) rtc_tm->tm_year += 100; rtc_tm->tm_mon--; } void get_rtc_alm_time(struct rtc_time *alm_tm) { unsigned char cmd; unsigned int flags; /* * Only the values that we read from the RTC are set. That * means only tm_wday, tm_hour, tm_min. */ spin_lock_irqsave(&ds1286_lock, flags); alm_tm->tm_min = CMOS_READ(RTC_MINUTES_ALARM) & 0x7f; alm_tm->tm_hour = CMOS_READ(RTC_HOURS_ALARM) & 0x1f; alm_tm->tm_wday = CMOS_READ(RTC_DAY_ALARM) & 0x07; cmd = CMOS_READ(RTC_CMD); spin_unlock_irqrestore(&ds1286_lock, flags); BCD_TO_BIN(alm_tm->tm_min); BCD_TO_BIN(alm_tm->tm_hour); alm_tm->tm_sec = 0; }