//-------------------------------------------------------------------
//	ioctl.c
//
//	This module implements a character device-driver which lets 
//	an application invoke 'ioctl()' system-calls that will hide 
//	or show the graphics hardware's cursor (for SiS 315 only).
//
//	programmer: ALLAN CRUSE
//	written on: 19 NOV 2004 -- for Linux kernel version 2.4.26
//	revised on: 16 MAR 2005 -- for Linux kernel version 2.6.10
//-------------------------------------------------------------------

#include <linux/module.h>	// for init_module() 
#include <linux/pci.h>		// for pci_find_device()

#define VENDOR_ID  0x1039	// Silicon Integrated Systems
#define	DEVICE_ID  0x6325 	// SiS 315 Graphics Processor
#define HIDE_CURSOR	0
#define SHOW_CURSOR	1

static char modname[] = "ioctl";
static char devname[] = "vram";
static int my_major = 99;
static unsigned long mmio_base;

static int my_ioctl( struct inode *inode, struct file *file, 
				unsigned int cmd, unsigned long arg )
{
	unsigned long	*cursor_control, *cursor_pos_x, *cursor_pos_y;
	unsigned long	command, pos_x, pos_y;
	void		*vaddr;

	vaddr = ioremap_nocache( mmio_base + 0x8000, PAGE_SIZE ); 
	cursor_control = vaddr + 0x500;
	cursor_pos_x = vaddr + 0x50C;
	cursor_pos_y = vaddr + 0x510;

	command = *cursor_control;
	pos_x = *cursor_pos_x;
	pos_y = *cursor_pos_y;

	switch ( cmd )
		{
		case HIDE_CURSOR:
			command &= 0x3FFFFFFF;
			command |= 0x80000000;
			break;

		case SHOW_CURSOR:
			command &= 0x3FFFFFFF;
			command |= 0xC0000000;
			break;
		}

	*cursor_control = command;
	*cursor_pos_x = pos_x;
	*cursor_pos_y = pos_y;
	iounmap( vaddr );
	return	0;  // SUCCESS
}


static struct file_operations 
my_fops =	{
		owner:		THIS_MODULE,
		ioctl:		my_ioctl,
		};


int init_module( void )
{
	struct pci_dev	*devp = NULL; 

	printk( "<1>\nInstalling \'%s\' module\n", modname );
	printk( "  device-file is \'/dev/%s\' ", devname );
	printk( "(major=%d) \n", my_major ); 

	devp = pci_find_device( VENDOR_ID, DEVICE_ID, devp );
	if ( !devp ) return -ENODEV;

	mmio_base = pci_resource_start( devp, 1 );
	printk( "  SiS 315 graphics processor:" ); 
	printk( "  mmio_base=%08lX \n", mmio_base );

	register_chrdev( my_major, devname, &my_fops );
	return	0;  // SUCCESS
}


void cleanup_module( void )
{
	unregister_chrdev( my_major, devname );
	printk( "<1>Removing \'%s\' module\n", modname );
}

MODULE_LICENSE("GPL");