//-------------------------------------------------------------------
//	idnumber.cpp
//
//	This program directly accesses the IDE Hard Disk Controller.
//	It issues the 'IDENTIFY DRIVE' command to obtain information
//	about the hard-disk's geometry and its unique serial number.
//	(NOTE: The 'iopl()' system-call requires 'root' privileges.)
//
//	programmer: ALLAN CRUSE
//	written on: 29 AUG 2004
//-------------------------------------------------------------------

#include <sys/io.h>	// for iopl(), inb(), outb()  
#include <stdio.h>	// for printf(), perror()
#include <stdlib.h>	// for exit()
#include <string.h>	// for strncpy()

#define IDE_DATA_REG	0x1F0
#define IDE_ERR_REG	0x1F1
#define IDE_DRV_HEAD	0x1F6
#define IDE_STATUS	0x1F7
#define IDE_COMMAND	0x1F7
#define IDE_CONTROL	0x3F6
#define IDE_ALT_STAT	0x3F6
#define IDE_DEV_ADDR	0x3F7
#define IDENTIFY_DRIVE	0xEC

unsigned short buffer[ 256 ];
char 	serial_number[ 21 ];

int main( void )
{
	//---------------------------------------------------
	// ask Linux to allow programmed i/o from user-space
	//---------------------------------------------------
	if ( iopl( 3 ) < 0 ) { perror( "iopl" ); exit(1); }

	//--------------------------------------------------------
	// select which drive will be accessed (0=master/1=slave) 
	//--------------------------------------------------------
	// port 0x1F6 bits:  1 LBA 1 DRV HS3 HS2 HS1 HS0
	outb( 0xA0, IDE_DRV_HEAD );	// drive 0 selected
	
	//--------------------------------------
	// wait for 'device-not-busy' indicator
	//--------------------------------------
	// port 0x1F7 bits: BSY DRDY DF DSC DRQ CORR IDX ERR
	int	status, timeout = 1000;
	while ( --timeout ) 
		{
		status = inb( IDE_STATUS );
		if ( ( status & 0x80 ) == 0x00 ) break;
		}
	if ( timeout == 0 ) 
		{ printf( "Timeout -- Device is busy\n" ); exit(1); }

	//---------------------------------------------------
	// COMMAND PHASE: issue command (if drive is ready )
	//---------------------------------------------------
	asm(" cli ");		// disable interrupts
	status = inb( IDE_STATUS );
	if ( ( status & 0xC0 ) == 0x40 ) 
		{
		outb( IDENTIFY_DRIVE, IDE_COMMAND );
		}
	else	{
		asm(" sti ");	// reenable interrupts
		printf( "Device not ready for command\n" );
		exit(1);
		}

	//---------------------------------------------
	// DATA-TRANSFER PHASE: wait for DRQ indicator
	//---------------------------------------------
	timeout = 1000000;
	while ( --timeout )
		{
		status = inb( IDE_STATUS );	
		if ( ( status & 0x88 ) == 0x08 ) break;
		}
	if ( timeout == 0 )
		{ 
		asm(" sti ");	// reenable interrupts	
		printf( "Timeout! Data-Transfer unsuccessful\n" );
		exit(1);
		}	

	//------------------------------------------------------------
	// RESULT PHASE: transfer data from the drive's sector-buffer
	//------------------------------------------------------------
	for (int i = 0; i < 256; i++) buffer[ i ] = inw( IDE_DATA_REG );
	status = inb( IDE_STATUS );
	if ( ( status & 0x89 ) == 0x00 ) 
		asm( "sti " );	// reenable interrupts
	else	{
		int	error = inb( IDE_ERR_REG );	
		asm(" sti " );	// reenable interrupts
		printf( "Error during result-phase " );
		printf( "(status=%02X, error=%02X)\n", status, error );
		exit(1);
		}

	//--------------------------------------------
	// now we display some of the IDE information	
	//--------------------------------------------
	strncpy( serial_number, (char*)&buffer[ 10 ], 20 );
	printf( "\n\tDisk-Drive Serial Number: %s \n\n", serial_number );
}