Import 2.3.18pre1

[davej-history.git] / drivers / sgi / char / ds1286.c

/* $Id: ds1286.c,v 1.4 1999/06/17 13:29:03 ralf 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 <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/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 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);

#ifdef __SMP__
static spinlock_t ds1286_lock = SPIN_LOCK_UNLOCKED;
#endif

/*
 *      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;
}