text: /*
   *	Real Time Clock interface for Linux on the BVME6000
   *
   * 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/slab.h>
  #include <linux/ioport.h>
  #include <linux/capability.h>
  #include <linux/fcntl.h>
  #include <linux/init.h>
  #include <linux/poll.h>
  #include <linux/module.h>
  #include <linux/mc146818rtc.h>	/* For struct rtc_time and ioctls, etc */
  #include <linux/smp_lock.h>
  #include <linux/bcd.h>
  #include <asm/bvme6000hw.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 unsigned char days_in_mo[] =
  {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  
  static char rtc_status;
  
  static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
  		     unsigned long arg)
  {
  	volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
  	unsigned char msr;
  	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 */
  		msr = rtc->msr & 0xc0;
  		rtc->msr = 0x40;
  		memset(&wtime, 0, sizeof(struct rtc_time));
  		do {
  			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;
  		} while (wtime.tm_sec != BCD2BIN(rtc->bcd_sec));
  		rtc->msr = msr;
  		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) || (mon < 1) || (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);
  		/* Ensure clock and real-time-mode-register are accessible */
  		msr = rtc->msr & 0xc0;
  		rtc->msr = 0x40;
  
  		rtc->t0cr_rtmr = yrs%4;
  		rtc->bcd_tenms = 0;
  		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);
  		if (rtc_tm.tm_wday >= 0)
  			rtc->bcd_dow = BIN2BCD(rtc_tm.tm_wday+1);
  		rtc->t0cr_rtmr = yrs%4 | 0x08;
  
  		rtc->msr = msr;
  		local_irq_restore(flags);
  		return 0;
  	}
  	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.
   */
  
  static int rtc_open(struct inode *inode, struct file *file)
  {
  	if(rtc_status)
  		return -EBUSY;
  
  	rtc_status = 1;
  	return 0;
  }
  
  static int rtc_release(struct inode *inode, struct file *file)
  {
  	lock_kernel();
  	rtc_status = 0;
  	unlock_kernel();
  	return 0;
  }
  
  /*
   *	The various file operations we support.
   */
  
  static const struct file_operations rtc_fops = {
  	.ioctl =	rtc_ioctl,
  	.open =		rtc_open,
  	.release =	rtc_release,
  };
  
  static struct miscdevice rtc_dev = {
  	.minor =	RTC_MINOR,
  	.name =		"rtc",
  	.fops =		&rtc_fops
  };
  
  static int __init rtc_DP8570A_init(void)
  {
  	if (!MACH_IS_BVME6000)
  		return -ENODEV;
  
  	printk(KERN_INFO "DP8570A Real Time Clock Driver v%s\n", RTC_VERSION);
  	return misc_register(&rtc_dev);
  }
  module_init(rtc_DP8570A_init);
  