//-------------------------------------------------------------------
//	mch.c
//	
//	This Linux kernel module creates a '/proc' interface to the 
//	PCI Configuration Space Header for the system's Host-to-PCI 
//	Memory Controller Hub.  (We are interested in studying this
//	because of its role in enabling access to System Management
//	Ram where an SMI interrupt-handler would be resident.)  Our
//	custom 'Makefile' is recommended for compiling this module:
//
//		compile using:  $ make mch.o
//		install using:  $ /sbin/insmod mch.o
//		execute using:  $ cat /proc/mch
//		removed using:  $ /sbin/rmmod mch
//
//	NOTE: Developed and tested with Linux kernel version 2.4.21.
//
//	programmer: ALLAN CRUSE
//	written on: 12 MAY 2004
//-------------------------------------------------------------------

#define	__KERNEL__
#define	  MODULE  

#include <linux/module.h>	// for init_module() 
#include <linux/pci.h>		// for pci_find_class()
#include <linux/proc_fs.h>	// for create_proc_read_entry()

#define	SUCCESS	0
#define HUB_CLASS 0x060000

static char modname[] = "mch";
struct pci_dev	*devp = NULL;

static int my_proc_read( char *buf, char **start, off_t off,
				int count, int *eof, void *data )
{
	u32	datum;	
	int	i, len = 0;

	len += sprintf( buf+len, "\n%s -- ", devp->name );
	len += sprintf( buf+len, "PCI Configuration Header \n" );
	for (i = 0; i < 256; i+=4)
		{
		if ( ( i % 32 ) == 0 ) 
			len += sprintf( buf+len, "\n%02X: ", i );
		pci_read_config_dword( devp, i, &datum );
		len += sprintf( buf+len, "%08X ", datum );
		}
	len += sprintf( buf+len, "\n\n" );

	*eof = 1;
	return	len;
}



int init_module( void )
{
	printk( "<1>\nInstalling \'%s\' module\n", modname );

	devp = pci_find_class( HUB_CLASS, devp );
	if ( !devp ) return -ENODEV;
	printk( "<1> %s \n", devp->name );

	create_proc_read_entry( modname, 0, NULL, my_proc_read, NULL );
	return	SUCCESS;
}


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

MODULE_LICENSE("GPL");