#define PCSPEAKER_VERSION "1.0"
#define PCSPEAKER_MINOR 240

#include <linux/module.h>
#include <linux/config.h>
#include <linux/sched.h>
#include <linux/smp_lock.h>

#if !defined(__i386__) && !defined(__x86_64__)
#error Cannot build speaker driver for this machine configuration.
#endif

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/ioport.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/spinlock.h>
#include <linux/vt_kern.h>
#include <linux/timex.h>

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

static int pcspeaker_open_cnt;	/* #times opened */
static int pcspeaker_open_mode;	/* special open modes */
#define	PCSPEAKER_WRITE	1	/* opened for writing (exclusive) */
#define	PCSPEAKER_EXCL	2	/* opened with O_EXCL */

/* I don't know how to link this module agains _kd_mktone() in
   drivers/char/vt.c -- Ilguiz Latypov
 */

/*
 * Generates sound of some frequency for some number of clock ticks
 *
 * If freq is 0, will turn off sound, else will turn it on for that time.
 * If msec is 0, will return immediately, else will sleep for msec time, then
 * turn sound off.
 *
 * We also return immediately, which is what was implied within the X
 * comments - KDMKTONE doesn't put the process to sleep.
 */

#if defined(__i386__) || defined(__alpha__) || defined(__powerpc__) \
    || (defined(__mips__) && defined(CONFIG_ISA)) \
    || (defined(__arm__) && defined(CONFIG_HOST_FOOTBRIDGE)) \
    || defined(__x86_64__)

static void
kd_nosound(unsigned long ignored)
{
	/* disable counter 2 */
	outb(inb_p(0x61)&0xFC, 0x61);
	return;
}

void
_kd_mksound2(unsigned int hz, unsigned int ticks)
{
	static struct timer_list sound_timer = { function: kd_nosound };
	unsigned int count = 0;
	unsigned long flags;

	if (hz > 20 && hz < 32767)
		count = 1193180 / hz;
	
	save_flags(flags);
	cli();
	del_timer(&sound_timer);
	if (count) {
		/* enable counter 2 */
		outb_p(inb_p(0x61)|3, 0x61);
		/* set command for counter 2, 2 byte write */
		outb_p(0xB6, 0x43);
		/* select desired HZ */
		outb_p(count & 0xff, 0x42);
		outb((count >> 8) & 0xff, 0x42);

		if (ticks) {
			sound_timer.expires = jiffies+ticks;
			add_timer(&sound_timer);
		}
	} else
		kd_nosound(0);
	restore_flags(flags);
	return;
}

#else

void
_kd_mksound2(unsigned int hz, unsigned int ticks)
{
}

#endif

static long long pcspeaker_llseek(struct file *file,loff_t offset, int origin )
{
	return 0;
}

static ssize_t pcspeaker_read(struct file * file,
	char * buf, size_t count, loff_t *ppos )
{
	return 0;
}

static ssize_t pcspeaker_write(struct file * file,
		const char * buf, size_t count, loff_t *ppos )
{
	return 0;
}

static int pcspeaker_ioctl( struct inode *inode, struct file *file,
				unsigned int cmd, unsigned long arg )
{
	int perm;
	
	perm = 0;
	if (suser())
		perm = 1;
 
	switch( cmd ) {
	case KIOCSOUND:
		if (!perm)
			return -EPERM;
		if (arg)
			arg = CLOCK_TICK_RATE / arg;
		_kd_mksound2(arg, 0);
		return 0;

	case KDMKTONE:
		if (!perm)
			return -EPERM;
	{
		unsigned int ticks, count;
		
		/*
		 * Generate the tone for the appropriate number of ticks.
		 * If the time is zero, turn off sound ourselves.
		 */
		ticks = HZ * ((arg >> 16) & 0xffff) / 1000;
		count = ticks ? (arg & 0xffff) : 0;
		if (count)
			count = CLOCK_TICK_RATE / count;
		_kd_mksound2(count, ticks);
		return 0;
	}
	  default:
		return( -EINVAL );
	}
}

static int pcspeaker_open( struct inode *inode, struct file *file )
{
	if ((pcspeaker_open_cnt && (file->f_flags & O_EXCL)) ||
		(pcspeaker_open_mode & PCSPEAKER_EXCL) ||
		((file->f_mode & 2) && (pcspeaker_open_mode & PCSPEAKER_WRITE)))
		return( -EBUSY );

	if (file->f_flags & O_EXCL)
		pcspeaker_open_mode |= PCSPEAKER_EXCL;
	if (file->f_mode & 2)
		pcspeaker_open_mode |= PCSPEAKER_WRITE;
	pcspeaker_open_cnt++;
	return( 0 );
}

static int pcspeaker_release( struct inode *inode, struct file *file )
{
	lock_kernel();
	pcspeaker_open_cnt--;
	if (file->f_flags & O_EXCL)
		pcspeaker_open_mode &= ~PCSPEAKER_EXCL;
	if (file->f_mode & 2)
		pcspeaker_open_mode &= ~PCSPEAKER_WRITE;
	unlock_kernel();

	return( 0 );
}

static struct file_operations pcspeaker_fops = {
	owner:		THIS_MODULE,
	llseek:		pcspeaker_llseek,
	read:		pcspeaker_read,
	write:		pcspeaker_write,
	ioctl:		pcspeaker_ioctl,
	open:		pcspeaker_open,
	release:	pcspeaker_release,
};

static struct miscdevice pcspeaker_dev = {
	PCSPEAKER_MINOR,
	"pcspeaker",
	&pcspeaker_fops
};


static int __init pcspeaker_init(void)
{
	int ret;

	ret = misc_register( &pcspeaker_dev );
	if (ret) {
		printk(KERN_ERR "pcspeaker: can't misc_register on minor=%d\n", PCSPEAKER_MINOR);
		goto out;
	}
	ret = 0;
	printk(KERN_INFO "PC speaker driver v" PCSPEAKER_VERSION "\n");
out:
	return( ret );
#if 0
outmisc:
	misc_deregister( &pcspeaker_dev );
	goto out;
#endif
}

static void __exit pcspeaker_cleanup_module (void)
{
	misc_deregister( &pcspeaker_dev );
}

module_init(pcspeaker_init);
module_exit(pcspeaker_cleanup_module);

MODULE_LICENSE("GPL");

EXPORT_NO_SYMBOLS;

/*
 * Local variables:
 *  c-indent-level: 4
 *  tab-width: 4
 *  compile-command: "gcc -pipe -mpreferred-stack-boundary=2 -march=i386  -O2 -D__KERNEL__ -I../include -I/home/ilatypov/linux/include -Wall -Wstrict-prototypes -fomit-frame-pointer -fno-strict-aliasing  -DMODULE -DMODVERSIONS -include /home/ilatypov/linux/include/linux/modversions.h -c pcspeaker.c -o pcspeaker.o"
 * End:
 */