ds1286.c
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上传日期:2013-04-10
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文件大小:13k
- /*
- * DS1286 Real Time Clock interface for Linux
- *
- * Copyright (C) 1998, 1999, 2000 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 <linux/types.h>
- #include <linux/errno.h>
- #include <linux/miscdevice.h>
- #include <linux/slab.h>
- #include <linux/ioport.h>
- #include <linux/fcntl.h>
- #include <linux/init.h>
- #include <linux/poll.h>
- #include <linux/rtc.h>
- #include <linux/spinlock.h>
- #include <asm/ds1286.h>
- #include <asm/io.h>
- #include <asm/uaccess.h>
- #include <asm/system.h>
- #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 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 ds1286_get_alm_time (struct rtc_time *alm_tm);
- void ds1286_get_time(struct rtc_time *rtc_tm);
- int ds1286_set_time(struct rtc_time *rtc_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; /* bitmapped status byte. */
- unsigned long ds1286_freq; /* Current periodic IRQ rate */
- unsigned char days_in_mo[] =
- {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
- /*
- * Now all the various file operations that we export.
- */
- static ssize_t ds1286_read(struct file *file, char *buf,
- size_t count, loff_t *ppos)
- {
- return -EIO;
- }
- 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.
- */
- ds1286_get_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 */
- {
- ds1286_get_time(&wtime);
- break;
- }
- case RTC_SET_TIME: /* Set the RTC */
- {
- struct rtc_time rtc_tm;
- if (!capable(CAP_SYS_TIME))
- return -EACCES;
- if (copy_from_user(&rtc_tm, (struct rtc_time*)arg,
- sizeof(struct rtc_time)))
- return -EFAULT;
- return ds1286_set_time(&rtc_tm);
- }
- 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)
- {
- spin_lock_irq(&ds1286_lock);
- if (ds1286_status & RTC_IS_OPEN)
- goto out_busy;
- ds1286_status |= RTC_IS_OPEN;
- spin_lock_irq(&ds1286_lock);
- return 0;
- out_busy:
- spin_lock_irq(&ds1286_lock);
- return -EBUSY;
- }
- 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);
- return 0;
- }
- /*
- * The various file operations we support.
- */
- static struct file_operations ds1286_fops = {
- llseek: no_llseek,
- read: ds1286_read,
- poll: ds1286_poll,
- ioctl: ds1286_ioctl,
- open: ds1286_open,
- release: 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%sn", 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;
- ds1286_get_time(&tm);
- hundredth = CMOS_READ(RTC_HUNDREDTH_SECOND);
- BCD_TO_BIN(hundredth);
- p += sprintf(p,
- "rtc_timet: %02d:%02d:%02d.%02dn"
- "rtc_datet: %04d-%02d-%02dn",
- 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.
- */
- ds1286_get_alm_time(&tm);
- p += sprintf(p, "alarmtt: %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, "%02dn", tm.tm_min);
- else
- p += sprintf(p, "**n");
- month = CMOS_READ(RTC_MONTH);
- p += sprintf(p,
- "oscillatort: %sn"
- "square_wavet: %sn",
- (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_modet: %sn", s);
- cmd = CMOS_READ(RTC_CMD);
- p += sprintf(p,
- "alarm_enablet: %sn"
- "wdog_alarmt: %sn"
- "alarm_maskt: %sn"
- "wdog_alarm_maskt: %sn"
- "interrupt_modet: %sn"
- "INTB_modet: %s_activen"
- "interrupt_pinst: %sn",
- (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 ds1286_get_time(struct rtc_time *rtc_tm)
- {
- unsigned char save_control;
- unsigned int flags;
- unsigned long uip_watchdog = jiffies;
- /*
- * 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--;
- }
- int ds1286_set_time(struct rtc_time *rtc_tm)
- {
- unsigned char mon, day, hrs, min, sec, leap_yr;
- unsigned char save_control;
- unsigned int yrs, flags;
- 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;
- }
- void ds1286_get_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;
- }