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[/] [or1k/] [trunk/] [uclinux/] [uClinux-2.0.x/] [drivers/] [char/] [rtc.c] - Blame information for rev 1765

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/*
 *      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/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.
 *
 */
 
#define RTC_VERSION             "1.09"
 
#define RTC_IRQ         8       /* Can't see this changing soon.        */
#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 <linux/types.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/malloc.h>
#include <linux/ioport.h>
#include <linux/fcntl.h>
#include <linux/mc146818rtc.h>
 
#include <asm/io.h>
#include <asm/segment.h>
#include <asm/system.h>
 
/*
 *      We sponge a minor off of the misc major. No need slurping
 *      up another valuable major dev number for this.
 */
 
#define RTC_MINOR       135
 
static struct wait_queue *rtc_wait;
 
static struct timer_list rtc_irq_timer;
 
static int rtc_lseek(struct inode *inode, struct file *file, off_t offset,
                        int origin);
 
static int rtc_read(struct inode *inode, struct file *file,
                        char *buf, int count);
 
static int rtc_ioctl(struct inode *inode, struct file *file,
                        unsigned int cmd, unsigned long arg);
 
static int rtc_select(struct inode *inode, struct file *file,
                        int sel_type, select_table *wait);
 
void get_rtc_time (struct rtc_time *rtc_tm);
void get_rtc_alm_time (struct rtc_time *alm_tm);
void rtc_dropped_irq(unsigned long data);
 
void set_rtc_irq_bit(unsigned char bit);
void mask_rtc_irq_bit(unsigned char bit);
 
static inline unsigned char rtc_is_updating(void);
 
/*
 *      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 rtc_status = 0;            /* bitmapped status byte.       */
unsigned long rtc_freq = 0;              /* Current periodic IRQ rate    */
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   */
 
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.)
 *
 *      On Alpha we won't get any interrupts anyway, as they all end up
 *      in the system timer code.
 */
 
#ifndef __alpha__
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.
         */
 
        rtc_irq_data += 0x100;
        rtc_irq_data &= ~0xff;
        rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0);
        wake_up_interruptible(&rtc_wait);
 
        if (rtc_status & RTC_TIMER_ON) {
                del_timer(&rtc_irq_timer);
                rtc_irq_timer.expires = jiffies + HZ/rtc_freq + 2*HZ/100;
                add_timer(&rtc_irq_timer);
        }
}
#endif
 
/*
 *      Now all the various file operations that we export.
 *      They are all useless on Alpha...  *sigh*.
 */
 
static int rtc_lseek(struct inode *inode, struct file *file, off_t offset,
        int origin)
{
        return -ESPIPE;
}
 
static int rtc_read(struct inode *inode, struct file *file, char *buf, int count)
{
#ifdef __alpha__
        return -EIO;
#else
        struct wait_queue wait = { current, NULL };
        int retval;
 
        if (count < sizeof(unsigned long))
                return -EINVAL;
 
        retval = verify_area(VERIFY_WRITE, buf, sizeof(unsigned long));
        if (retval)
                return retval;
 
        add_wait_queue(&rtc_wait, &wait);
 
        current->state = TASK_INTERRUPTIBLE;
 
        while (rtc_irq_data == 0) {
                if (file->f_flags & O_NONBLOCK) {
                        retval = -EAGAIN;
                        break;
                }
                if (current->signal & ~current->blocked) {
                        retval = -ERESTARTSYS;
                        break;
                }
                schedule();
        }
 
        if (retval == 0) {
                unsigned long data, flags;
                save_flags(flags);
                cli();
                data = rtc_irq_data;
                rtc_irq_data = 0;
                restore_flags(flags);
                memcpy_tofs(buf, &data, sizeof(unsigned long));
                retval = sizeof(unsigned long);
        }
 
        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)
{
 
        unsigned long flags;
 
        switch (cmd) {
#ifndef __alpha__
                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) {
                                del_timer(&rtc_irq_timer);
                                rtc_status &= ~RTC_TIMER_ON;
                        }
                        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) && (!suser()))
                                return -EACCES;
 
                        if (!(rtc_status & RTC_TIMER_ON)) {
                                rtc_status |= RTC_TIMER_ON;
                                rtc_irq_timer.expires = jiffies + HZ/rtc_freq + 2*HZ/100;
                                add_timer(&rtc_irq_timer);
                        }
                        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.
                         */
                        int retval;
                        struct rtc_time alm_tm;
 
                        retval = verify_area(VERIFY_WRITE, (struct rtc_time*)arg, sizeof(struct rtc_time));
                        if (retval != 0 )
                                return retval;
 
                        get_rtc_alm_time(&alm_tm);
 
                        memcpy_tofs((struct rtc_time*)arg, &alm_tm, sizeof(struct rtc_time));
 
                        return 0;
                }
                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.
                         */
                        int retval;
                        unsigned char hrs, min, sec;
                        struct rtc_time alm_tm;
 
                        retval = verify_area(VERIFY_READ, (struct rtc_time*)arg, sizeof(struct rtc_time));
                        if (retval != 0 )
                                return retval;
 
                        memcpy_fromfs(&alm_tm, (struct rtc_time*)arg, sizeof(struct rtc_time));
 
                        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;
 
                        save_flags(flags);
                        cli();
                        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);
                        restore_flags(flags);
 
                        return 0;
                }
                case RTC_RD_TIME:       /* Read the time/date from RTC  */
                {
                        int retval;
                        struct rtc_time rtc_tm;
 
                        retval = verify_area(VERIFY_WRITE, (struct rtc_time*)arg, sizeof(struct rtc_time));
                        if (retval !=0 )
                                return retval;
 
                        get_rtc_time(&rtc_tm);
                        memcpy_tofs((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time));
                        return 0;
                }
                case RTC_SET_TIME:      /* Set the RTC */
                {
                        int retval;
                        struct rtc_time rtc_tm;
                        unsigned char mon, day, hrs, min, sec, leap_yr;
                        unsigned char save_control, save_freq_select;
                        unsigned int yrs;
                        unsigned long flags;
 
                        if (!suser())
                                return -EACCES;
 
                        retval = verify_area(VERIFY_READ, (struct rtc_time*)arg, sizeof(struct rtc_time));
                        if (retval !=0 )
                                return retval;
 
                        memcpy_fromfs(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time));
 
                        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;
 
                        save_flags(flags);
                        cli();
                        if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
                                if (yrs > 169) {
                                        restore_flags(flags);
                                        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);
                        }
 
                        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);
 
                        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);
 
                        restore_flags(flags);
                        return 0;
                }
                case RTC_IRQP_READ:     /* Read the periodic IRQ rate.  */
                {
                        int retval;
 
                        retval = verify_area(VERIFY_WRITE, (unsigned long*)arg, sizeof(unsigned long));
                        if (retval != 0)
                                return retval;
 
                        memcpy_tofs((unsigned long*)arg, &rtc_freq, sizeof(unsigned long));
                        return 0;
                }
#ifndef __alpha__
                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) && (!suser()))
                                return -EACCES;
 
                        while (arg > (1<<tmp))
                                tmp++;
 
                        /*
                         * Check that the input was really a power of 2.
                         */
                        if (arg != (1<<tmp))
                                return -EINVAL;
 
                        rtc_freq = arg;
 
                        save_flags(flags);
                        cli();
                        val = CMOS_READ(RTC_FREQ_SELECT) & 0xf0;
                        val |= (16 - tmp);
                        CMOS_WRITE(val, RTC_FREQ_SELECT);
                        restore_flags(flags);
                        return 0;
                }
#endif
#ifdef __alpha__
                case RTC_EPOCH_READ:    /* Read the epoch.      */
                {
                        int retval;
 
                        retval = verify_area(VERIFY_WRITE, (unsigned long*)arg, sizeof(unsigned long));
                        if (retval != 0)
                                return retval;
 
                        memcpy_tofs((unsigned long*)arg, &epoch, sizeof(unsigned long));
                        return 0;
                }
                case RTC_EPOCH_SET:     /* Set the epoch.       */
                {
                        /*
                         * There were no RTC clocks before 1900.
                         */
                        if (arg < 1900)
                                return -EINVAL;
 
                        if (!suser())
                                return -EACCES;
 
                        epoch = arg;
                        return 0;
                }
#endif
                default:
                        return -EINVAL;
        }
}
 
/*
 *      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.
 *      On Alpha we just open, for we don't mess with interrups anyway.
 */
 
static int rtc_open(struct inode *inode, struct file *file)
{
#ifndef __alpha__
        if(rtc_status & RTC_IS_OPEN)
                return -EBUSY;
 
        rtc_status |= RTC_IS_OPEN;
        rtc_irq_data = 0;
#endif
        return 0;
}
 
static void rtc_release(struct inode *inode, struct file *file)
{
 
        /*
         * Turn off all interrupts once the device is no longer
         * in use, and clear the data.
         */
 
#ifndef __alpha__
        unsigned char tmp;
        unsigned long flags;
 
        save_flags(flags);
        cli();
        tmp = CMOS_READ(RTC_CONTROL);
        tmp &=  ~RTC_PIE;
        tmp &=  ~RTC_AIE;
        tmp &=  ~RTC_UIE;
        CMOS_WRITE(tmp, RTC_CONTROL);
        CMOS_READ(RTC_INTR_FLAGS);
        restore_flags(flags);
 
        if (rtc_status & RTC_TIMER_ON) {
                rtc_status &= ~RTC_TIMER_ON;
                del_timer(&rtc_irq_timer);
        }
 
        rtc_irq_data = 0;
        rtc_status &= ~RTC_IS_OPEN;
#endif
}
 
#ifndef __alpha__
static int rtc_select(struct inode *inode, struct file *file,
                        int sel_type, select_table *wait)
{
        if (sel_type == SEL_IN) {
                if (rtc_irq_data != 0)
                        return 1;
                select_wait(&rtc_wait, wait);
        }
        return 0;
}
#endif
 
/*
 *      The various file operations we support.
 */
 
static struct file_operations rtc_fops = {
        rtc_lseek,
        rtc_read,
        NULL,           /* No write */
        NULL,           /* No readdir */
#ifdef __alpha__
        NULL,           /* No select on Alpha */
#else
        rtc_select,
#endif
        rtc_ioctl,
        NULL,           /* No mmap */
        rtc_open,
        rtc_release
};
 
static struct miscdevice rtc_dev=
{
        RTC_MINOR,
        "rtc",
        &rtc_fops
};
 
int rtc_init(void)
{
        unsigned long flags;
#ifdef __alpha__
        unsigned int year, ctrl;
        unsigned long uip_watchdog;
        char *guess = NULL;
#endif
 
        printk("Real Time Clock Driver v%s\n", RTC_VERSION);
#ifndef __alpha__
        if(request_irq(RTC_IRQ, rtc_interrupt, SA_INTERRUPT, "rtc", NULL))
        {
                /* Yeah right, seeing as irq 8 doesn't even hit the bus. */
                printk("rtc: IRQ %d is not free.\n", RTC_IRQ);
                return -EIO;
        }
#endif
        misc_register(&rtc_dev);
        /* Check region? Naaah! Just snarf it up. */
        request_region(RTC_PORT(0), RTC_IO_EXTENT, "rtc");
#ifdef __alpha__
        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();
 
        save_flags(flags);
        cli();
        year = CMOS_READ(RTC_YEAR);
        ctrl = CMOS_READ(RTC_CONTROL);
        restore_flags(flags);
 
        if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
                BCD_TO_BIN(year);       /* This should never happen... */
 
        if (year > 10 && year < 44) {
                epoch = 1980;
                guess = "ARC console";
        } else if (year < 96) {
                epoch = 1952;
                guess = "Digital UNIX";
        }
        if (guess)
                printk("rtc: %s epoch (%ld) detected\n", guess, epoch);
#else
        init_timer(&rtc_irq_timer);
        rtc_irq_timer.function = rtc_dropped_irq;
        rtc_wait = NULL;
        save_flags(flags);
        cli();
        /* Initialize periodic freq. to CMOS reset default, which is 1024Hz */
        CMOS_WRITE(((CMOS_READ(RTC_FREQ_SELECT) & 0xF0) | 0x06), RTC_FREQ_SELECT);
        restore_flags(flags);
        rtc_freq = 1024;
#endif
        return 0;
}
 
/*
 *      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.)
 */
 
#ifndef __alpha__
void rtc_dropped_irq(unsigned long data)
{
        unsigned long flags;
 
        printk(KERN_INFO "rtc: lost some interrupts at %ldHz.\n", rtc_freq);
        del_timer(&rtc_irq_timer);
        rtc_irq_timer.expires = jiffies + HZ/rtc_freq + 2*HZ/100;
        add_timer(&rtc_irq_timer);
 
        save_flags(flags);
        cli();
        rtc_irq_data += ((rtc_freq/HZ)<<8);
        rtc_irq_data &= ~0xff;
        rtc_irq_data |= (CMOS_READ(RTC_INTR_FLAGS) & 0xF0);     /* restart */
        restore_flags(flags);
}
#endif
 
/*
 *      Info exported via "/proc/rtc".
 */
 
int get_rtc_status(char *buf)
{
        char *p;
        struct rtc_time tm;
        unsigned char batt, ctrl;
        unsigned long flags;
 
        save_flags(flags);
        cli();
        batt = CMOS_READ(RTC_VALID) & RTC_VRT;
        ctrl = CMOS_READ(RTC_CONTROL);
        restore_flags(flags);
 
        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",
                tm.tm_hour, tm.tm_min, tm.tm_sec,
                tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
 
        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",
                (ctrl & RTC_DST_EN) ? "yes" : "no",
                (ctrl & RTC_DM_BINARY) ? "no" : "yes",
                (ctrl & RTC_24H) ? "yes" : "no",
                (ctrl & RTC_SQWE) ? "yes" : "no",
                (ctrl & RTC_AIE) ? "yes" : "no",
                (ctrl & RTC_UIE) ? "yes" : "no",
                (ctrl & RTC_PIE) ? "yes" : "no",
                rtc_freq,
                batt ? "okay" : "dead");
 
        return  p - buf;
}
 
/*
 * Returns true if a clock update is in progress
 */
static inline unsigned char rtc_is_updating(void)
{
        unsigned long flags;
        unsigned char uip;
 
        save_flags(flags);
        cli();
        uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
        restore_flags(flags);
        return uip;
}
 
void get_rtc_time(struct rtc_time *rtc_tm)
{
 
        unsigned long flags, uip_watchdog = jiffies;
        unsigned char ctrl;
 
        /*
         * 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();
 
        /*
         * 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.
         */
        save_flags(flags);
        cli();
        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);
        ctrl = CMOS_READ(RTC_CONTROL);
        restore_flags(flags);
 
        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);
        }
 
        /*
         * 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--;
}
 
void get_rtc_alm_time(struct rtc_time *alm_tm)
{
        unsigned long flags;
        unsigned char ctrl;
 
        /*
         * Only the values that we read from the RTC are set. That
         * means only tm_hour, tm_min, and tm_sec.
         */
        save_flags(flags);
        cli();
        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);
        restore_flags(flags);
 
        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);
        }
}
 
/*
 * 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.
 */
 
#ifndef __alpha__
void mask_rtc_irq_bit(unsigned char bit)
{
        unsigned char val;
        unsigned long flags;
 
        save_flags(flags);
        cli();
        val = CMOS_READ(RTC_CONTROL);
        val &=  ~bit;
        CMOS_WRITE(val, RTC_CONTROL);
        CMOS_READ(RTC_INTR_FLAGS);
        restore_flags(flags);
        rtc_irq_data = 0;
}
 
void set_rtc_irq_bit(unsigned char bit)
{
        unsigned char val;
        unsigned long flags;
 
        save_flags(flags);
        cli();
        val = CMOS_READ(RTC_CONTROL);
        val |= bit;
        CMOS_WRITE(val, RTC_CONTROL);
        CMOS_READ(RTC_INTR_FLAGS);
        rtc_irq_data = 0;
        restore_flags(flags);
}
#endif
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[/] [or1k/] [trunk/] [uclinux/] [uClinux-2.0.x/] [drivers/] [char/] [rtc.c] - Blame information for rev 1765

Line No.	Rev	Author	Line
1	199	simons	`/*`
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 /proc/rtc`
9			`* 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			`*`
36			`*/`
37
38			`#define RTC_VERSION "1.09"`
39
40			`#define RTC_IRQ 8 /* Can't see this changing soon. */`