/* $Id: rtc.c,v 1.28 2001/10/08 22:19:51 davem Exp $
 *
 * Linux/SPARC Real Time Clock Driver
 * Copyright (C) 1996 Thomas K. Dyas (tdyas@eden.rutgers.edu)
 *
 * This is a little driver that lets a user-level program access
 * the SPARC Mostek real time clock chip. It is no use unless you
 * use the modified clock utility.
 *
 * Get the modified clock utility from:
 *   ftp://vger.kernel.org/pub/linux/Sparc/userland/clock.c
 */

#include <linux/module.h>
#include <linux/smp_lock.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/fcntl.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <asm/io.h>
#include <asm/mostek.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/rtc.h>

static int rtc_busy = 0;

/* This is the structure layout used by drivers/char/rtc.c, we
 * support that driver's ioctls so that things are less messy in
 * userspace.
 */
struct rtc_time_generic {
	int tm_sec;
	int tm_min;
	int tm_hour;
	int tm_mday;
	int tm_mon;
	int tm_year;
	int tm_wday;
	int tm_yday;
	int tm_isdst;
};
#define RTC_AIE_ON	_IO('p', 0x01)	/* Alarm int. enable on		*/
#define RTC_AIE_OFF	_IO('p', 0x02)	/* ... off			*/
#define RTC_UIE_ON	_IO('p', 0x03)	/* Update int. enable on	*/
#define RTC_UIE_OFF	_IO('p', 0x04)	/* ... off			*/
#define RTC_PIE_ON	_IO('p', 0x05)	/* Periodic int. enable on	*/
#define RTC_PIE_OFF	_IO('p', 0x06)	/* ... off			*/
#define RTC_WIE_ON	_IO('p', 0x0f)  /* Watchdog int. enable on	*/
#define RTC_WIE_OFF	_IO('p', 0x10)  /* ... off			*/
#define RTC_RD_TIME	_IOR('p', 0x09, struct rtc_time_generic) /* Read RTC time   */
#define RTC_SET_TIME	_IOW('p', 0x0a, struct rtc_time_generic) /* Set RTC time    */
#define RTC_ALM_SET	_IOW('p', 0x07, struct rtc_time) /* Set alarm time  */
#define RTC_ALM_READ	_IOR('p', 0x08, struct rtc_time) /* Read alarm time */
#define RTC_IRQP_READ	_IOR('p', 0x0b, unsigned long)	 /* Read IRQ rate   */
#define RTC_IRQP_SET	_IOW('p', 0x0c, unsigned long)	 /* Set IRQ rate    */
#define RTC_EPOCH_READ	_IOR('p', 0x0d, unsigned long)	 /* Read epoch      */
#define RTC_EPOCH_SET	_IOW('p', 0x0e, unsigned long)	 /* Set epoch       */
#define RTC_WKALM_SET	_IOW('p', 0x0f, struct rtc_wkalrm)/* Set wakeup alarm*/
#define RTC_WKALM_RD	_IOR('p', 0x10, struct rtc_wkalrm)/* Get wakeup alarm*/
#define RTC_PLL_GET	_IOR('p', 0x11, struct rtc_pll_info)  /* Get PLL correction */
#define RTC_PLL_SET	_IOW('p', 0x12, struct rtc_pll_info)  /* Set PLL correction */

/* Retrieve the current date and time from the real time clock. */
static void get_rtc_time(struct rtc_time *t)
{
	void __iomem *regs = mstk48t02_regs;
	u8 tmp;

	spin_lock_irq(&mostek_lock);

	tmp = mostek_read(regs + MOSTEK_CREG);
	tmp |= MSTK_CREG_READ;
	mostek_write(regs + MOSTEK_CREG, tmp);

	t->sec = MSTK_REG_SEC(regs);
	t->min = MSTK_REG_MIN(regs);
	t->hour = MSTK_REG_HOUR(regs);
	t->dow = MSTK_REG_DOW(regs);
	t->dom = MSTK_REG_DOM(regs);
	t->month = MSTK_REG_MONTH(regs);
	t->year = MSTK_CVT_YEAR( MSTK_REG_YEAR(regs) );

	tmp = mostek_read(regs + MOSTEK_CREG);
	tmp &= ~MSTK_CREG_READ;
	mostek_write(regs + MOSTEK_CREG, tmp);

	spin_unlock_irq(&mostek_lock);
}

/* Set the current date and time inthe real time clock. */
void set_rtc_time(struct rtc_time *t)
{
	void __iomem *regs = mstk48t02_regs;
	u8 tmp;

	spin_lock_irq(&mostek_lock);

	tmp = mostek_read(regs + MOSTEK_CREG);
	tmp |= MSTK_CREG_WRITE;
	mostek_write(regs + MOSTEK_CREG, tmp);

	MSTK_SET_REG_SEC(regs,t->sec);
	MSTK_SET_REG_MIN(regs,t->min);
	MSTK_SET_REG_HOUR(regs,t->hour);
	MSTK_SET_REG_DOW(regs,t->dow);
	MSTK_SET_REG_DOM(regs,t->dom);
	MSTK_SET_REG_MONTH(regs,t->month);
	MSTK_SET_REG_YEAR(regs,t->year - MSTK_YEAR_ZERO);

	tmp = mostek_read(regs + MOSTEK_CREG);
	tmp &= ~MSTK_CREG_WRITE;
	mostek_write(regs + MOSTEK_CREG, tmp);

	spin_unlock_irq(&mostek_lock);
}

static int put_rtc_time_generic(void __user *argp, struct rtc_time *tm)
{
	struct rtc_time_generic __user *utm = argp;

	if (__put_user(tm->sec, &utm->tm_sec) ||
	    __put_user(tm->min, &utm->tm_min) ||
	    __put_user(tm->hour, &utm->tm_hour) ||
	    __put_user(tm->dom, &utm->tm_mday) ||
	    __put_user(tm->month, &utm->tm_mon) ||
	    __put_user(tm->year, &utm->tm_year) ||
	    __put_user(tm->dow, &utm->tm_wday) ||
	    __put_user(0, &utm->tm_yday) ||
	    __put_user(0, &utm->tm_isdst))
		return -EFAULT;

	return 0;
}

static int get_rtc_time_generic(struct rtc_time *tm, void __user *argp)
{
	struct rtc_time_generic __user *utm = argp;

	if (__get_user(tm->sec, &utm->tm_sec) ||
	    __get_user(tm->min, &utm->tm_min) ||
	    __get_user(tm->hour, &utm->tm_hour) ||
	    __get_user(tm->dom, &utm->tm_mday) ||
	    __get_user(tm->month, &utm->tm_mon) ||
	    __get_user(tm->year, &utm->tm_year) ||
	    __get_user(tm->dow, &utm->tm_wday))
		return -EFAULT;

	return 0;
}

static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
	unsigned long arg)
{
	struct rtc_time rtc_tm;
	void __user *argp = (void __user *)arg;

	switch (cmd) {
	/* No interrupt support, return an error
	 * compatible with drivers/char/rtc.c
	 */
	case RTC_AIE_OFF:
	case RTC_AIE_ON:
	case RTC_PIE_OFF:
	case RTC_PIE_ON:
	case RTC_UIE_OFF:
	case RTC_UIE_ON:
	case RTC_IRQP_READ:
	case RTC_IRQP_SET:
	case RTC_EPOCH_SET:
	case RTC_EPOCH_READ:
		return -EINVAL;

	case RTCGET:
	case RTC_RD_TIME:
		memset(&rtc_tm, 0, sizeof(struct rtc_time));
		get_rtc_time(&rtc_tm);

		if (cmd == RTCGET) {
			if (copy_to_user(argp, &rtc_tm,
					 sizeof(struct rtc_time)))
				return -EFAULT;
		} else if (put_rtc_time_generic(argp, &rtc_tm))
			return -EFAULT;

		return 0;


	case RTCSET:
	case RTC_SET_TIME:
		if (!capable(CAP_SYS_TIME))
			return -EPERM;

		if (cmd == RTCSET) {
			if (copy_from_user(&rtc_tm, argp,
					   sizeof(struct rtc_time)))
				return -EFAULT;
		} else if (get_rtc_time_generic(&rtc_tm, argp))
			return -EFAULT;

		set_rtc_time(&rtc_tm);

		return 0;

	default:
		return -EINVAL;
	}
}

static int rtc_open(struct inode *inode, struct file *file)
{
	int ret;

	lock_kernel();
	spin_lock_irq(&mostek_lock);
	if (rtc_busy) {
		ret = -EBUSY;
	} else {
		rtc_busy = 1;
		ret = 0;
	}
	spin_unlock_irq(&mostek_lock);
	unlock_kernel();

	return ret;
}

static int rtc_release(struct inode *inode, struct file *file)
{
	rtc_busy = 0;

	return 0;
}

static const struct file_operations rtc_fops = {
	.owner =	THIS_MODULE,
	.llseek =	no_llseek,
	.ioctl =	rtc_ioctl,
	.open =		rtc_open,
	.release =	rtc_release,
};

static struct miscdevice rtc_dev = { RTC_MINOR, "rtc", &rtc_fops };

static int __init rtc_sun_init(void)
{
	int error;

	/* It is possible we are being driven by some other RTC chip
	 * and thus another RTC driver is handling things.
	 */
	if (!mstk48t02_regs)
		return -ENODEV;

	error = misc_register(&rtc_dev);
	if (error) {
		printk(KERN_ERR "rtc: unable to get misc minor for Mostek\n");
		return error;
	}
	printk("rtc_sun_init: Registered Mostek RTC driver.\n");

	return 0;
}

static void __exit rtc_sun_cleanup(void)
{
	misc_deregister(&rtc_dev);
}

module_init(rtc_sun_init);
module_exit(rtc_sun_cleanup);
MODULE_LICENSE("GPL");