/*
   *	Real Time Clock interface for Linux on the MVME16x
   *
   * Based on the PC driver by Paul Gortmaker.
   */
  
  #define RTC_VERSION		"1.00"
  
  #include <linux/types.h>
  #include <linux/errno.h>
  #include <linux/miscdevice.h>

  #include <linux/ioport.h>

  #include <linux/capability.h>

  #include <linux/fcntl.h>
  #include <linux/init.h>
  #include <linux/poll.h>
  #include <linux/mc146818rtc.h>	/* For struct rtc_time and ioctls, etc */

  #include <linux/bcd.h>

  #include <asm/mvme16xhw.h>
  
  #include <asm/io.h>
  #include <asm/uaccess.h>
  #include <asm/system.h>
  #include <asm/setup.h>
  
  /*
   *	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 const unsigned char days_in_mo[] =
  {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  
  static atomic_t rtc_ready = ATOMIC_INIT(1);

  static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)

  {
  	volatile MK48T08ptr_t rtc = (MK48T08ptr_t)MVME_RTC_BASE;
  	unsigned long flags;
  	struct rtc_time wtime;

  	void __user *argp = (void __user *)arg;

  
  	switch (cmd) {
  	case RTC_RD_TIME:	/* Read the time/date from RTC	*/
  	{
  		local_irq_save(flags);
  		/* Ensure clock and real-time-mode-register are accessible */
  		rtc->ctrl = RTC_READ;
  		memset(&wtime, 0, sizeof(struct rtc_time));

  		wtime.tm_sec =  bcd2bin(rtc->bcd_sec);
  		wtime.tm_min =  bcd2bin(rtc->bcd_min);
  		wtime.tm_hour = bcd2bin(rtc->bcd_hr);
  		wtime.tm_mday =  bcd2bin(rtc->bcd_dom);
  		wtime.tm_mon =  bcd2bin(rtc->bcd_mth)-1;
  		wtime.tm_year = bcd2bin(rtc->bcd_year);

  		if (wtime.tm_year < 70)
  			wtime.tm_year += 100;

  		wtime.tm_wday = bcd2bin(rtc->bcd_dow)-1;

  		rtc->ctrl = 0;
  		local_irq_restore(flags);

  		return copy_to_user(argp, &wtime, sizeof wtime) ?

  								-EFAULT : 0;
  	}
  	case RTC_SET_TIME:	/* Set the RTC */
  	{
  		struct rtc_time rtc_tm;
  		unsigned char mon, day, hrs, min, sec, leap_yr;
  		unsigned int yrs;
  
  		if (!capable(CAP_SYS_ADMIN))
  			return -EACCES;

  		if (copy_from_user(&rtc_tm, argp, sizeof(struct rtc_time)))

  			return -EFAULT;
  
  		yrs = rtc_tm.tm_year;
  		if (yrs < 1900)
  			yrs += 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;
  
  		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 >= 2070)
  			return -EINVAL;
  
  		local_irq_save(flags);
  		rtc->ctrl     = RTC_WRITE;

  		rtc->bcd_sec  = bin2bcd(sec);
  		rtc->bcd_min  = bin2bcd(min);
  		rtc->bcd_hr   = bin2bcd(hrs);
  		rtc->bcd_dom  = bin2bcd(day);
  		rtc->bcd_mth  = bin2bcd(mon);
  		rtc->bcd_year = bin2bcd(yrs%100);

  
  		rtc->ctrl     = 0;
  		local_irq_restore(flags);
  		return 0;
  	}
  	default:
  		return -EINVAL;
  	}
  }
  
  /*

   * We enforce only one user at a time here with the open/close.

   */

  static int rtc_open(struct inode *inode, struct file *file)
  {
  	if( !atomic_dec_and_test(&rtc_ready) )
  	{
  		atomic_inc( &rtc_ready );
  		return -EBUSY;
  	}

  	return 0;
  }
  
  static int rtc_release(struct inode *inode, struct file *file)
  {
  	atomic_inc( &rtc_ready );
  	return 0;
  }
  
  /*
   *	The various file operations we support.
   */

  static const struct file_operations rtc_fops = {

  	.unlocked_ioctl	= rtc_ioctl,
  	.open		= rtc_open,
  	.release	= rtc_release,

  	.llseek		= noop_llseek,

  };
  
  static struct miscdevice rtc_dev=
  {
  	.minor =	RTC_MINOR,
  	.name =		"rtc",
  	.fops =		&rtc_fops
  };

  static int __init rtc_MK48T08_init(void)

  {
  	if (!MACH_IS_MVME16x)
  		return -ENODEV;
  
  	printk(KERN_INFO "MK48T08 Real Time Clock Driver v%s
  ", RTC_VERSION);
  	return misc_register(&rtc_dev);
  }

  module_init(rtc_MK48T08_init);