pcwd.c

讲述linux的初始化过程

				return -EFAULT;
		return 0;

	case WDIOC_SETOPTIONS:
		if (revision == PCWD_REVISION_C) 
		{
			if(copy_from_user(&rv, (int*) arg, sizeof(int)))
				return -EFAULT;

			if (rv & WDIOS_DISABLECARD) 
			{
				spin_lock(&io_lock);
				outb_p(0xA5, current_readport + 3);
				outb_p(0xA5, current_readport + 3);
				cdat = inb_p(current_readport + 2);
				spin_unlock(&io_lock);
				if ((cdat & 0x10) == 0) 
				{
					printk("pcwd: Could not disable card.\n");
					return -EIO;
				}

				return 0;
			}

			if (rv & WDIOS_ENABLECARD) 
			{
				spin_lock(&io_lock);
				outb_p(0x00, current_readport + 3);
				cdat = inb_p(current_readport + 2);
				spin_unlock(&io_lock);
				if (cdat & 0x10) 
				{
					printk("pcwd: Could not enable card.\n");
					return -EIO;
				}
				return 0;
			}

			if (rv & WDIOS_TEMPPANIC) 
			{
				temp_panic = 1;
			}
		}
		return -EINVAL;
		
	case WDIOC_KEEPALIVE:
		pcwd_send_heartbeat();
		return 0;
	}

	return 0;
}

static ssize_t pcwd_write(struct file *file, const char *buf, size_t len,
			  loff_t *ppos)
{
	/*  Can't seek (pwrite) on this device  */
	if (ppos != &file->f_pos)
		return -ESPIPE;

	if (len)
	{
		pcwd_send_heartbeat();
		return 1;
	}
	return 0;
}

static int pcwd_open(struct inode *ino, struct file *filep)
{
        switch (MINOR(ino->i_rdev))
        {
                case WATCHDOG_MINOR:
                    if (is_open)
                        return -EBUSY;
                    MOD_INC_USE_COUNT;
                    /*  Enable the port  */
                    if (revision == PCWD_REVISION_C)
                    {
                    	spin_lock(&io_lock);
                    	outb_p(0x00, current_readport + 3);
                    	spin_unlock(&io_lock);
                    }
                    is_open = 1;
                    return(0);
                case TEMP_MINOR:
                    return(0);
                default:
                    return (-ENODEV);
        }
}

static ssize_t pcwd_read(struct file *file, char *buf, size_t count,
			 loff_t *ppos)
{
	unsigned short c;
	unsigned char cp;

	/*  Can't seek (pread) on this device  */
	if (ppos != &file->f_pos)
		return -ESPIPE;
	switch(MINOR(file->f_dentry->d_inode->i_rdev)) 
	{
		case TEMP_MINOR:
			/*
			 * Convert metric to Fahrenheit, since this was
			 * the decided 'standard' for this return value.
			 */
			
			c = inb(current_readport);
			cp = (c * 9 / 5) + 32;
			if(copy_to_user(buf, &cp, 1))
				return -EFAULT;
			return 1;
		default:
			return -EINVAL;
	}
}

static int pcwd_close(struct inode *ino, struct file *filep)
{
	if (MINOR(ino->i_rdev)==WATCHDOG_MINOR)
	{
		lock_kernel();
	        is_open = 0;
#ifndef CONFIG_WATCHDOG_NOWAYOUT
		/*  Disable the board  */
		if (revision == PCWD_REVISION_C) {
			spin_lock(&io_lock);
			outb_p(0xA5, current_readport + 3);
			outb_p(0xA5, current_readport + 3);
			spin_unlock(&io_lock);
		}
		unlock_kernel();
#endif
	}
	return 0;
}

static inline void get_support(void)
{
	if (inb(current_readport) != 0xF0)
		supports_temp = 1;
}

static inline int get_revision(void)
{
	int r = PCWD_REVISION_C;
	
	spin_lock(&io_lock);
	if ((inb(current_readport + 2) == 0xFF) ||
	    (inb(current_readport + 3) == 0xFF))
		r=PCWD_REVISION_A;
	spin_unlock(&io_lock);

	return r;
}

static int __init send_command(int cmd)
{
	int i;

	outb_p(cmd, current_readport + 2);
	mdelay(1);

	i = inb(current_readport);
	i = inb(current_readport);

	return(i);
}

static inline char *get_firmware(void)
{
	int i, found = 0, count = 0, one, ten, hund, minor;
	char *ret;

	ret = kmalloc(6, GFP_KERNEL);

	while((count < 3) && (!found)) {
		outb_p(0x80, current_readport + 2);
		i = inb(current_readport);

		if (i == 0x00)
			found = 1;
		else if (i == 0xF3)
			outb_p(0x00, current_readport + 2);

		udelay(400L);
		count++;
	}

	if (found) {
		mode_debug = 1;

		one = send_command(0x81);
		ten = send_command(0x82);
		hund = send_command(0x83);
		minor = send_command(0x84);
	}

	if (found)
		sprintf(ret, "%c.%c%c%c", one, ten, hund, minor);
	else
		sprintf(ret, "ERROR");

	return(ret);
}

static void debug_off(void)
{
	outb_p(0x00, current_readport + 2);
	mode_debug = 0;
}

static struct file_operations pcwd_fops = {
	owner:		THIS_MODULE,
	read:		pcwd_read,
	write:		pcwd_write,
	ioctl:		pcwd_ioctl,
	open:		pcwd_open,
	release:	pcwd_close,
};

static struct miscdevice pcwd_miscdev = {
	WATCHDOG_MINOR,
	"watchdog",
	&pcwd_fops
};

static struct miscdevice temp_miscdev = {
	TEMP_MINOR,
	"temperature",
	&pcwd_fops
};
 
static int __init pcwatchdog_init(void)
{
	int i, found = 0;
	spin_lock_init(&io_lock);
	
	revision = PCWD_REVISION_A;

	printk("pcwd: v%s Ken Hollis ([e-mail])\n", WD_VER);

	/* Initial variables */
	is_open = 0;
	supports_temp = 0;
	mode_debug = 0;
	temp_panic = 0;
	initial_status = 0x0000;

#ifndef	PCWD_BLIND
	for (i = 0; pcwd_ioports[i] != 0; i++) {
		current_readport = pcwd_ioports[i];

		if (pcwd_checkcard()) {
			found = 1;
			break;
		}
	}

	if (!found) {
		printk("pcwd: No card detected, or port not available.\n");
		return(-EIO);
	}
#endif

#ifdef	PCWD_BLIND
	current_readport = PCWD_BLIND;
#endif

	get_support();
	revision = get_revision();

	if (revision == PCWD_REVISION_A)
		printk("pcwd: PC Watchdog (REV.A) detected at port 0x%03x\n", current_readport);
	else if (revision == PCWD_REVISION_C)
		printk("pcwd: PC Watchdog (REV.C) detected at port 0x%03x (Firmware version: %s)\n",
			current_readport, get_firmware());
	else {
		/* Should NEVER happen, unless get_revision() fails. */
		printk("pcwd: Unable to get revision.\n");
		return -1;
	}

	if (supports_temp)
		printk("pcwd: Temperature Option Detected.\n");

	debug_off();

	pcwd_showprevstate();

	/*  Disable the board  */
	if (revision == PCWD_REVISION_C) {
		outb_p(0xA5, current_readport + 3);
		outb_p(0xA5, current_readport + 3);
	}

	if (revision == PCWD_REVISION_A)
		request_region(current_readport, 2, "PCWD Rev.A (Berkshire)");
	else
		request_region(current_readport, 4, "PCWD Rev.C (Berkshire)");

	misc_register(&pcwd_miscdev);

	if (supports_temp)
		misc_register(&temp_miscdev);

	return 0;
}

static void __exit pcwatchdog_exit(void)
{
	/*  Disable the board  */
	if (revision == PCWD_REVISION_C) {
		outb_p(0xA5, current_readport + 3);
		outb_p(0xA5, current_readport + 3);
	}
	misc_deregister(&pcwd_miscdev);
	if (supports_temp)
		misc_deregister(&temp_miscdev);

	release_region(current_readport, (revision == PCWD_REVISION_A) ? 2 : 4);
}

module_init(pcwatchdog_init);
module_exit(pcwatchdog_exit);