//-------------------------------------------------------------------
//	ajayecho.cpp
//
//	This program illustrates our programming of data transfers
//	using a Hi-Speed USB Debug Cable made by Ajays Technology:
//	the data received will get transferred back to its sender.
//	It relies upon the services of our 'ajay.c' kernel module,
//	and it expects data to be sent by our 'ajayxfer.cpp' demo.
//
//		to compile:  $ g++ ajayecho.cpp -o ajayecho
//		to execute:  $ ./ajayecho
//
//
//	Reference: 
//	"USB2 Debug Device: A Functional Specification (Rev 0.9)"
//	online at: <http://www.intel.com/technology/usb/spec.htm>
//
//	programmer: ALLAN CRUSE
//	written on: 31 JAN 2010
//	revised on: 07 FEB 2010 -- added <Control>-C signal-handler
//-------------------------------------------------------------------

#include <stdio.h>	// for printf(), perror() 
#include <fcntl.h>	// for open() 
#include <stdlib.h>	// for exit() 
#include <unistd.h>	// for lseek(), usleep() 
#include <signal.h>	// for signal()
#include <sys/mman.h>	// for mmap()

#define AJAYBASE    0x80000	// suitable address for io-mapping 
#define BULKSIZE    512		// maximum size of 'bulk' transfer

unsigned int	*lp = (unsigned int*)AJAYBASE;	// registers array
char devname[] = "/dev/ajay";	// name for our driver device-node

void my_sigint_handler( int signo )
{
	exit(1);
}

int initiate_debug_port_transaction( unsigned int *lp )
{
	lp[ 0xA0 >> 2 ] = lp[ 0xA0 >> 2 ] | (1 << 5);	// set the GO bit
	while ( ( lp[ 0xA0 >> 2 ] & (1 << 16)) == 0 );	// await DONE bit
	return	( ( lp[ 0xA0 >> 2 ] >> 6 )&0xF );	// GOOD or ERROR
}	

void display_controller_registers( unsigned int *lp )
{
	printf( " USB2CMD=%08X ",  lp[ 0x20 >> 2 ] );
	printf( " USB2STS=%08X ",  lp[ 0x24 >> 2 ] );
	printf( " PORT0SC=%08X ",  lp[ 0x64 >> 2 ] );
	printf( " CNTL_STS=%08X ", lp[ 0xA0 >> 2 ] ); 
	printf( "\n" );
}

void release_debug_port_ownership( void )
{
	printf( "\n\n Quitting... \n" );
	lp[ 0xA0 >> 2 ] = 0x00010000;	// OWNER_CTL=0, ENABLE_CTL=0
	display_controller_registers( lp );
}  	

void exhibit_debug_port_registers( unsigned int *lp )
{
	unsigned int	token_pid = (lp[ 0xA4 >> 2 ] >> 0)&0xFF;
	unsigned int	recv_pid = (lp[ 0xA4 >> 2 ] >> 16)&0xFF;

	switch( token_pid )
		{
		case 0x2D:  printf( "\r   SETUP: " ); break;
		case 0x69:  printf( "\r      IN: " ); break;
		case 0xE1:  printf( "\r     OUT: " ); break;
		default:    printf( "\r          " ); break;
		}

	printf( " CNTL_STS=%08X ", lp[ 0xA0 >> 2 ] );
	printf( " USBPID=%06X ", lp[ 0xA4 >> 2 ] );
	printf( " DATABUF=%08X-%08X ", lp[ 0xA8 >> 2 ], lp[ 0xAC >> 2 ] );

	switch ( recv_pid )
		{
		case 0xD2:  printf( "(ACK)  " ); break;
		case 0x5A:  printf( "(NAK)  " ); break;
		case 0x96:  printf( "(NYET) " ); break;
		case 0x1E:  printf( "(STALL)" ); break;
		case 0xC3:  printf( "(DATA0)" ); break;
		case 0x4B:  printf( "(DATA1)" ); break;
		default:    printf( "(--?--)" ); break;
		}
}	

int main( int argc, char **argv )
{
	int	err;

	// open the device-file for reading and writing
	int	fd = open( devname, O_RDWR );
	if ( fd < 0 ) { perror( devname ); exit(1); }

	// map the EHCI registers to user-space
	int	size = lseek( fd, 0, SEEK_END );
	int	prot = PROT_READ | PROT_WRITE;
	int	flag = MAP_FIXED | MAP_SHARED;
	void	*mm = (void*)AJAYBASE;
	if ( mmap( mm, size, prot, flag, fd, 0 ) == MAP_FAILED )
		{ perror( "mmap" ); exit(1); }

	// insure that debug port 'ownership' will get released 
	atexit( release_debug_port_ownership );
	signal( SIGINT, my_sigint_handler );

	// show state of the relevant EHCI controller registers
	printf( "\n Detecting... \n" );
	printf( " CONFIGFLAG=%X ", lp[ 0x60 >> 2 ] ); 
	printf( " USB2INTR=%08X ", lp[ 0x28 >> 2 ] );
	printf( "\n" );
	display_controller_registers( lp );
	printf( "\n" );

	// interpret readiness of the EHCI for Debug Port usage
	unsigned int	port0sc = lp[ 0x64 >> 2 ];
	unsigned int	cfgflag = lp[ 0x60 >> 2 ];
	unsigned int	dbgcmd =  lp[ 0xA0 >> 2 ];
	unsigned int	usbpid  = lp[ 0xA4 >> 2 ];
	unsigned int	config  = lp[ 0xB0 >> 2 ];
	
	if ( cfgflag == 1 ) printf( " EHCI initialized" );
	else { printf( "\n EHCI controller is uninitialized " ); exit(1); }
	if ( (port0sc & 1)==1 ) printf( ", Port 0 connected" );
	else { printf( "\n Port 0 is not connected " ); exit(1); }
	if ( ( (port0sc >> 13)&1 )==0 ) printf( ", but not owned" );
	else { printf( "\n Port 0 is already owned " ); exit(1); }
	if ( ( (dbgcmd >> 30)&1 )==0 ) printf( ", Debug Port available" );
	else { printf( "\n Debug Port is already owned " ); exit(1); }
	printf( "\n\n" ); 

	// initiate Port 0 reset
	port0sc = lp[ 0x64 >> 2 ];	// read current PORT0SC bits
	port0sc &= ~(1 << 13);		// clear Port0 'owned' bit
	port0sc &= ~(1 << 2);		// clear Port0 'enabled' bit
	port0sc |= (1 << 8 );		// set the Port0 'reset' bit
	lp[ 0x64 >> 2 ] = port0sc;	// write revised PORT0SC bits
	usleep( 50000 );		// delay for 50 milliseconds
	// terminate Port 0 reset
	port0sc = lp[ 0x64 >> 2 ];	// read current PORT0SC bits
	port0sc &= ~(1 << 8 );		// clear the Port0 'reset' bit
	lp[ 0x64 >> 2 ] = port0sc;	// write revised PORT0SC bits
	usleep( 2000 );			// delay for 2 milliseconds	

	// configure the Debug Port
	printf( " Configuring... \n" );
	lp[ 0xA0 >> 2 ] = 0x50010000;
	printf( " USB2CMD=%08X ", lp[ 0x20 >> 2 ] );
	printf( " USB2STS=%08X ", lp[ 0x24 >> 2 ] );
	printf( " PORT0SC=%08X ", lp[ 0x64 >> 2 ] );
	printf( " CNTL_STS=%08X ", lp[ 0xA0 >> 2 ] ); 
	printf( "\n" );

	// implement the 'Get_Descriptor' control-transfer 
	printf( "\n Initiating our 'GET_DESCRIPTOR' control-transfer: \n" );

	// 1. the SETUP stage (Get_Descriptor)
	lp[ 0xB0 >> 2 ] = 0x00000000; 	// CONFIG: device=0, endpoint=0
	lp[ 0xA8 >> 2 ] = 0x0A000680;	// DATA_31: bRequest=6, wValue=10
	lp[ 0xAC >> 2 ] = 0x00080000;	// DATA_74: wIndex=0, wLength=8
	lp[ 0xA4 >> 2 ] = 0x0000C32D;	// USBPID: SETUP, DATA0
	lp[ 0xA0 >> 2 ] = 0x50010018;	// CNTL_STS: transmit 8 bytes

	err = initiate_debug_port_transaction( lp );
	exhibit_debug_port_registers( lp );
	printf( "\n");
	if ( err ) exit( 1 );

	// 2. the DATA stage (Get_Descriptor)
	lp[ 0xA8 >> 2 ] = 0x00000000;	// DATABUF_31: all zeros
	lp[ 0xAC >> 2 ] = 0x00000000;	// DATABUF_74: all zeros
	lp[ 0xA4 >> 2 ] = 0x0000C369;	// USBPID: IN, DATA0
	lp[ 0xA0 >> 2 ] = 0x50010008;	// CNTL_STS: receive 4 bytes
		
	err = initiate_debug_port_transaction( lp );
	exhibit_debug_port_registers( lp );
	printf( "\n");
	if ( err ) exit( 1 );

	// 3. the HANDSHAKE (Get_Descriptor)
	lp[ 0xA4 >> 2 ] = 0x0000C3E1;	// USBPID: OUT, DATA0
	lp[ 0xA0 >> 2 ] = 0x50010010;	// CNTL_STS: transmit 0 bytes
		
	err = initiate_debug_port_transaction( lp );
	exhibit_debug_port_registers( lp );
	printf( "\n");
	if ( err ) exit( 1 );

	// check for an unexpected peripheral attached to Port 0
	usbpid = lp[ 0xA4 >> 2 ];
	if ( (usbpid >> 16) != 0xD2 ) 
		{
		printf( " Handshake was not 'ACK' " );
		printf( "(i.e., Port 0 not attached to Debug Peripheral) " );
		exit(1); 
		}

	// show the Debug Descriptor
	unsigned char	descriptor[ 8 ];
	*(unsigned int *)( descriptor+0 ) = lp[ 0xA8 >> 2 ];	
	*(unsigned int *)( descriptor+4 ) = lp[ 0xAC >> 2 ];	
	printf( "\n Debug Descriptor: " );
	for (int i = 0; i < 4; i++) printf( " %02X", descriptor[ i ] ); 
	printf( "\n" );

	// Now implement the 'Set_Feature' control-transfer
	printf( "\n Initiating our 'SET_FEATURE' control-transfer: \n" );

	// 1. the SETUP stage (Set_Feature)
	lp[ 0xA8 >> 2 ] = 0x00060300;	// DATABUF_30: bRequest=3, wValue=6
	lp[ 0xAC >> 2 ] = 0x00000000;	// DATABUF_73: wIndex=0, wLength=0
	lp[ 0xA4 >> 2 ] = 0x0000C32D;	// USBPID: SETUP, DATA0
	lp[ 0xA0 >> 2 ] = 0x50010018;	// CNTL_STS: transmit 8 bytes 

	err = initiate_debug_port_transaction( lp );
	exhibit_debug_port_registers( lp );
	printf( "\n");
	if ( err ) exit( 1 );

	// 2. the optional DATA phase (Set_Feature)
	lp[ 0xA4 >> 2 ] = 0x0000C369;	// USBPID: IN, DATA0
	lp[ 0xA0 >> 2 ] = 0x50010000;	// CNTL_STS: receive 0 bytes

	err = initiate_debug_port_transaction( lp );
	exhibit_debug_port_registers( lp );
	printf( "\n");
	if ( err ) exit( 1 );

	// 3. the HANDSHAKE phase (Set_Feature)
	lp[ 0xA4 >> 2 ] = 0x00004BE1;	// USBPID: OUT, DATA1
	lp[ 0xA0 >> 2 ] = 0x50010010;	// CNTL_STS: transmit 0 bytes

	err = initiate_debug_port_transaction( lp );
	exhibit_debug_port_registers( lp );
	printf( "\n");
	if ( err ) exit( 1 );

	//=========================================================
	// LOOP TO PERFORM THE 'IN' TRANSFERS
	//=========================================================
	printf( "\n\n Now awaiting data from link-partner... \n" );

	config = 0x00000002;	// CONFIG: device=0, endpoint=2
	usbpid = 0x0000C369;	// USBPID: IN, DATA0
	dbgcmd = 0x50010008;	// CNTL_STS: receive 8 bytes

	char	databuf[ BULKSIZE + 8 ] = { 0 };

	int	rxbytes = 0;
	int	where = 0;
	do	{
		lp[ 0xA8 >> 2 ] = 0x00000000;	// DATABUF_30
		lp[ 0xAC >> 2 ] = 0x00000000;	// DATABUF_74
		lp[ 0xB0 >> 2 ] = config;	// CONFIG: 
		lp[ 0xA4 >> 2 ] = usbpid;	// USBPID: 
		lp[ 0xA0 >> 2 ] = dbgcmd;	// CNTL_SYS

		err = initiate_debug_port_transaction( lp );
		exhibit_debug_port_registers( lp );
		if ( err ) exit( 1 );

		dbgcmd = lp[ 0xA0 >> 2 ];
		usbpid = lp[ 0xA4 >> 2 ];
		if ( (usbpid >> 16) != 0x5A ) printf( "\n" );	
		else	continue;	// status was 'NAK'
	
		*(unsigned int *)( databuf + where + 0 ) = lp[ 0xA8 >> 2 ];
		*(unsigned int *)( databuf + where + 4 ) = lp[ 0xAC >> 2 ];
		where += 8;
		usbpid ^= 0x00008800;
		rxbytes += ( dbgcmd & 0x0F );
		if ( ( dbgcmd & 0x0F ) < 8 ) break;
		else	dbgcmd = 0x50010008;
		}
	while ( where < BULKSIZE );

	printf( "\n OK, received %d bytes from link partner \n\n", rxbytes );

	databuf[ rxbytes ] = '\0';
	printf( "%s\n", databuf );

	//==========================================================
	// LOOP TO PERFORM THE 'OUT' TRANSFERS
	//========================================================== 
	printf( "\n Now returning %d bytes to link partner... \n", rxbytes );

	config = 0x00000001;	// CONFIG: device=0, endpoint=1
	usbpid = 0x0000C3E1;	// USBPID: OUT, DATA0
	dbgcmd = 0x50010018;	// CNTL_STS: transmit 8 bytes

	int 	out_count = 0;
	int	to_do = rxbytes;
	where = 0;
	do	{
		if ( ( out_count % 3 ) == 0 ) usleep( 1000 );
		++out_count;

		if ( to_do < 8 ) dbgcmd = 0x50010010 | to_do;
		lp[ 0xA8 >> 2 ] = *(unsigned int *)( databuf + where + 0 ); 	
		lp[ 0xAC >> 2 ] = *(unsigned int *)( databuf + where + 4 ); 	
		lp[ 0xB0 >> 2 ] = config;	// CONFIG
		lp[ 0xA4 >> 2 ] = usbpid;	// USBPID
		lp[ 0xA0 >> 2 ] = dbgcmd;	// CNTL_STS
	
		err = initiate_debug_port_transaction( lp );
		exhibit_debug_port_registers( lp );
		printf( "\n");
		if ( err ) exit( 1 );

		// NOTE: The Debug Device specification says:
		// "NYET responses from the OUT endpoints 
		// must be equivalent to an ACK response."
		// see 'Device Requirements' on page 2

		dbgcmd = lp[ 0xA0 >> 2 ];
		usbpid = lp[ 0xA4 >> 2 ];

		if ( (usbpid >> 16) == 0x5A ) 	// status 'NAK'
			{ usleep( 1000 ); continue; }		

		usbpid ^= 0x00008800;
		where += 8;
		to_do -= 8;
		}
	while ( to_do >= 0 );
}