rtc.c

freescale的关于Imax21的rtc程序,好用

/******************************************************************************
	Copyright (C) 2002 Motorola GSG-China

	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.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*******************************************************************************/

#define RTC_VERSION	"0.3.0"

#define HW_2HZ

#define RTC_IO_EXTENT	0x10	/* Only really two ports, but...	*/

#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/ioport.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <linux/spinlock.h>
#include <linux/rtc.h>

#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/system.h>

#define DAYR			0xf0204020
#define HOURMIN			0xf0204000
#define SECONDS			0xf0204004
#define DAYALARM		0xf0204024
#define ALRM_HM			0xf0204008
#define ALRM_SEC		0xf020400c
#define RCCTL			0xf0204010
#define RTCISR			0xf0204014
#define RTCIENR			0xf0204018
#define STPWCH			0xf020401c

#define RTC_AIE			0x0004
#define RTC_PIE			0xff80
#define RTC_UIE			0x0010
#define RTC_SIE			0x0001

#define RTC_IRQ			17
#ifdef _DEBUG_RTC
#	define RTC_DB(fmt, args...) 	printk("\n[%s]:[line%d]----"fmt, __FILE__, __LINE__, ## args)
#	define RTC_LOC			printk(KERN_ERR"\nCurrent Location [%s]:[%d]\n", __FILE__, __LINE__)
#	define FUNC_START		printk(KERN_ERR"\n[%s]:start!\n", __FUNCTION__)
#	define FUNC_END			printk(KERN_ERR"\n[%s]:end!\n", __FUNCTION__)
#	define CLUE(arg)		printk(" %s\n",arg)

#else
#	define RTC_DB(fmt, args...)
#	define RTC_LOC
#	define FUNC_START
#	define FUNC_END
#endif

#define TRY_SLEEPON


//#define _DEBUG_RTC
struct rtc_time rtc_timer;
static struct fasync_struct *rtc_async_queue;

#ifdef TRY_SLEEPON
wait_queue_head_t rtc_wait;
#else
static DECLARE_WAIT_QUEUE_HEAD(rtc_wait);
#endif

extern spinlock_t rtc_lock;

static struct timer_list rtc_irq_timer;

static loff_t rtc_llseek(struct file *file, loff_t offset, int origin);

static ssize_t rtc_read(struct file *file, char *buf,
			size_t count, loff_t *ppos);

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

#if RTC_IRQ
static unsigned int rtc_poll(struct file *file, poll_table *wait);
#endif

static void get_rtc_time (struct rtc_time *rtc_tm);
static void get_rtc_alm_time (struct rtc_time *alm_tm);
#if RTC_IRQ
static void rtc_dropped_irq(unsigned long data);

static void set_rtc_irq_bit(unsigned int bit);
static void mask_rtc_irq_bit(unsigned int bit);
#endif

static int rtc_read_proc(char *page, char **start, off_t off,
                         int count, int *eof, void *data);


unsigned int READREG(unsigned int r)
{
	return *(volatile unsigned int *)r;
}
void WRITEREG(unsigned int r, unsigned int val)
{
	*(volatile unsigned int *)r = val;
}

/*
 *	Bits in rtc_status. (6 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	*/

/*
 * rtc_status is never changed by rtc_interrupt, and ioctl/open/close is
 * protected by the big kernel lock. However, ioctl can still disable the timer
 * in rtc_status and then with del_timer after the interrupt has read
 * rtc_status but before mod_timer is called, which would then reenable the
 * timer (but you would need to have an awful timing before you'd trip on it)
 */
static unsigned long rtc_status = 0;	/* bitmapped status byte.	*/
static unsigned long rtc_freq = 0;	/* Current periodic IRQ rate	*/
static unsigned long rtc_irq_data = 0;	/* our output to the world	*/
static unsigned long before_wk = 0;     /* the seconds value before set the stopwatch */

/*
 *	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	*/

static const unsigned char days_in_mo[] = 
{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

#if RTC_IRQ
/*
 *	A very tiny interrupt handler. It runs with SA_INTERRUPT set,
 *	but there is possibility of conflicting with the set_rtc_mmss()
 *	call (the rtc irq and the timer irq can easily run at the same
 *	time in two different CPUs). So we need to serializes
 *	accesses to the chip with the rtc_lock spinlock that each
 *	architecture should implement in the timer code.
 *	(See ./arch/XXXX/kernel/time.c for the set_rtc_mmss() function.)
 */

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.
	 */
	static int freq_2HZ = 0;
	unsigned long isr;

#ifndef HW_2HZ
	if ((rtc_freq == 2 ) && (freq_2HZ == 0))
	{	
		freq_2HZ = 1;
		/* clear RTCISR */
		WRITEREG(RTCISR, READREG(RTCISR)); 
		
		return;
	}
#endif

	freq_2HZ = 0;
	spin_lock (&rtc_lock);
	rtc_irq_data += 0x10000; /* 0x100 */
	rtc_irq_data &= ~0xffff;
	rtc_irq_data |= (READREG(RTCISR) & 0xffff);
	RTC_DB(" rtc_irq_data 0x%lx",rtc_irq_data);
	//acknowledge the interrupt 	
	isr =READREG(RTCISR);
	RTC_DB("before setting RTCISR is 0x%lx",isr);

	WRITEREG(RTCISR, READREG(RTCISR)); 

	isr =READREG(RTCISR);
	RTC_DB("aftre setting RTCISR is 0x%lx",isr);

	if (rtc_status & RTC_TIMER_ON)
		mod_timer(&rtc_irq_timer, jiffies + HZ/rtc_freq + 2*HZ/100);

	spin_unlock (&rtc_lock);

	/* Now do the rest of the actions */
	wake_up_interruptible(&rtc_wait);	

	kill_fasync (&rtc_async_queue, SIGIO, POLL_IN);
	
}
#endif

/*
 *	Now all the various file operations that we export.
 */

static loff_t rtc_llseek(struct file *file, loff_t offset, int origin)
{
	return -ESPIPE;
}

#ifdef  ZHIMING_VERSION
static ssize_t rtc_read(struct file *file, char *buf,
			size_t count, loff_t *ppos)
{
	//	FUNC_START; //??? why error here?

#if !RTC_IRQ
	return -EIO;
#else
	DECLARE_WAITQUEUE(wait, current);
	unsigned long data,j;
	ssize_t retval;
	
	if (count < sizeof(unsigned long))
		return -EINVAL;
#if 0
	add_wait_queue(&rtc_wait, &wait);

	current->state = TASK_INTERRUPTIBLE;
#endif	
	
	do {
		/* First make it right. The make it fast. Putting this whole
		 * block within the parentheses of a while would be too
		 * confusing. And no, xchg() is not the answer. */
		spin_lock_irq (&rtc_lock);
		data = rtc_irq_data;
		rtc_irq_data = 0;
		spin_unlock_irq (&rtc_lock);

		if (data != 0)
			break;

		if (file->f_flags & O_NONBLOCK) {
			retval = -EAGAIN;
			goto out;
		}
#if 0
		if (signal_pending(current)) {
			retval = -ERESTARTSYS;
			goto out;
		}
		schedule();
#endif
	} while (1);
	/* wait some seconds to get the accurate watchstop */
#if 1
	j = jiffies+before_wk*HZ;
	RTC_DB("befor_wk = 0x%lx",before_wk);
	before_wk = 0;
	while(jiffies < j)
		schedule();
#endif
#if 0
	current ->timeout = j;
	current->state = TASK_INTERRUPTIBLE;
	schedule();
	current ->timeout = 0;
#endif
	retval = put_user(data, (unsigned long *)buf); 
	if (!retval)
		retval = sizeof(unsigned long); 
 out:
#if 0
	current->state = TASK_RUNNING;
	remove_wait_queue(&rtc_wait, &wait);
#endif
	
	return retval;
#endif
}
#else //!ZHIMING_VERSION
static ssize_t rtc_read(struct file *file, char *buf,
			size_t count, loff_t *ppos)
{
	//	FUNC_START; //??? why error here?

#if !RTC_IRQ
	return -EIO;
#else
#ifdef TRY_SLEEPON
	unsigned long data;
	unsigned int j;
	ssize_t retval;

	if(count < sizeof(unsigned long))
		return -EINVAL;

	/* First make it right. The make it fast. Putting this whole
	 * block within the parentheses of a while would be too
	 * confusing. And no, xchg() is not the answer. */
	spin_lock_irq (&rtc_lock);
	data = rtc_irq_data;
	rtc_irq_data = 0;
	spin_unlock_irq (&rtc_lock);

	if(file->f_flags & O_NONBLOCK){
		if(!data)
			return -EAGAIN;
		retval = put_user(data, (unsigned long *)buf); 
		return retval; 
	}else{
		while(1){ //ensure copy to user or block
			spin_lock_irq (&rtc_lock);
			data = rtc_irq_data;
			rtc_irq_data = 0;
			spin_unlock_irq (&rtc_lock);
			if(data){
#if 1
	j = jiffies+before_wk*HZ;
	RTC_DB("befor_wk = 0x%lx",before_wk);
	before_wk = 0;
	while(jiffies < j)
		schedule();
#endif
				return put_user(data, (unsigned long *)buf);
			}else{
				interruptible_sleep_on(&rtc_wait);
				// TODO
				if(signal_pending(current))
					return -ERESTARTSYS;
			}
		}
	}
	
#else //!TRY_SLEEPON
	DECLARE_WAITQUEUE(wait, current);
	unsigned long data;
	ssize_t retval;
	
	if (count < sizeof(unsigned long))
		return -EINVAL;
	add_wait_queue(&rtc_wait, &wait);

	current->state = TASK_INTERRUPTIBLE;
	
	do {
		/* First make it right. The make it fast. Putting this whole
		 * block within the parentheses of a while would be too
		 * confusing. And no, xchg() is not the answer. */
		spin_lock_irq (&rtc_lock);
		data = rtc_irq_data;
		rtc_irq_data = 0;
		spin_unlock_irq (&rtc_lock);

		if (data != 0)
			break;

		if (file->f_flags & O_NONBLOCK) {
			retval = -EAGAIN;
			goto out;
		}
		if (signal_pending(current)) {
			retval = -ERESTARTSYS;
			goto out;
		}
		schedule();
	} while (1);
	
	retval = put_user(data, (unsigned long *)buf); 
	if (!retval)
		retval = sizeof(unsigned long); 
out: 
	current->state = TASK_RUNNING;
	remove_wait_queue(&rtc_wait, &wait);
	
	return retval;
#endif // TRY_SLEEPON
#endif // !RTC_IRQ
}
#endif // ZhimingVersion


static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
		     unsigned long arg)
{
	struct rtc_time wtime;
//	unsigned int j;
	
	;
	switch (cmd) {
#if RTC_IRQ
	case RTC_WIE_OFF:	/* mask stop watch int. enab. bit */
	{
		mask_rtc_irq_bit(RTC_SIE);
		return 0;
	}
	case RTC_WIE_ON:
	{
		set_rtc_irq_bit(RTC_SIE);
		return 0;
	}
	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_freq ==1 ? rtc_freq <<4 : rtc_freq << 6);
		if (rtc_status & RTC_TIMER_ON) {
			spin_lock_irq (&rtc_lock);
			rtc_status &= ~RTC_TIMER_ON;
			del_timer(&rtc_irq_timer);
			spin_unlock_irq (&rtc_lock);
		}
		return 0;
	}
	case RTC_PIE_ON:	/* Allow periodic int in RTCISR [bit 7~bit 15]*/
	{

		/*
		 * We don't really want Joe User enabling more
		 * than 64Hz of interrupts on a multi-user machine.
		 * you can see linux\include\linux\capablities.h 
		 */
		if ((rtc_freq > 64) && (!capable(CAP_SYS_RESOURCE)))
			return -EACCES;
		
		if (!(rtc_status & RTC_TIMER_ON)) {
			spin_lock_irq (&rtc_lock);
			rtc_irq_timer.expires = jiffies + HZ/rtc_freq + 2*HZ/100;
			add_timer(&rtc_irq_timer);
			rtc_status |= RTC_TIMER_ON;
			spin_unlock_irq (&rtc_lock);
		}	
		/* rtc_freq = 1HZ RTCISR[bit :4]
		 * rtc_freq = 2HZ RTCISR[bit :7]
		 * rtc_freq = 4HZ RTCISR[bit :8]
		 * ...
		 * rtc_freq = 512HZ RTCISR[bit :15]
		 */
		//set_rtc_irq_bit(rtc_freq << 6);		
		set_rtc_irq_bit((rtc_freq ==1) ? (rtc_freq<<4): (rtc_freq<<6));		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_WKALM_SET:
	{
		if (arg > 0x3f)
			return -EFAULT;
		spin_lock_irq(&rtc_lock);
		before_wk = READREG(SECONDS) & 0x3f;
		WRITEREG(STPWCH, arg);
		spin_unlock_irq(&rtc_lock);
		return 0;
	}
	case RTC_WKALM_RD:
	{
		unsigned int val;

		val = READREG(STPWCH);

		return put_user(val, (unsigned long *)arg);
	}
	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 day, hrs, min, sec;