avrdude/src/avrftdi.c

/*
 * avrftdi - extension for avrdude, Wolfgang Moser, Ville Voipio
 * Copyright (C) 2011 Hannes Weisbach, Doug Springer
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

/* $Id$ */
/*
 * Interface to the MPSSE Engine of FTDI Chips using libftdi.
 */
#include "ac_cfg.h"

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdint.h>
#include <stdarg.h>

#include "avrdude.h"
#include "libavrdude.h"

#include "avrftdi.h"
#include "avrftdi_tpi.h"
#include "avrftdi_private.h"
#include "usbdevs.h"

#ifndef MAX
#define MAX(a,b) ((a)>(b)?(a):(b))
#endif
#ifndef MIN
#define MIN(a,b) ((a)<(b)?(a):(b))
#endif

#ifdef DO_NOT_BUILD_AVRFTDI

static int avrftdi_noftdi_open(PROGRAMMER *pgm, const char *name) {
	avrdude_message(MSG_INFO, "%s: Error: no libftdi or libusb support. Install libftdi1/libusb-1.0 or libftdi/libusb and run configure/make again.\n",
                        progname);

	return -1;
}

void avrftdi_initpgm(PROGRAMMER *pgm) {
	strcpy(pgm->type, "avrftdi");
	pgm->open = avrftdi_noftdi_open;
}

#else

enum { FTDI_SCK = 0, FTDI_MOSI, FTDI_MISO, FTDI_RESET };

static int write_flush(avrftdi_t *);

/*
 * returns a human-readable name for a pin number. The name should match with
 * the pin names used in FTDI datasheets.
 */
static char*
ftdi_pin_name(avrftdi_t* pdata, struct pindef_t pin)
{
	static char str[128];

	char interface = '@';

	/* INTERFACE_ANY is zero, so @ is used
	 * INTERFACE_A is one, so '@' + 1 = 'A'
	 * and so forth ...
	 * be aware, there is an 'interface' member in ftdi_context,
	 * however, we really want the 'index' member here.
	 */
	interface += pdata->ftdic->index;

	int pinno;
	int n = 0;
	int mask = pin.mask[0];

	const char * fmt;

	str[0] = 0;

	for(pinno = 0; mask; mask >>= 1, pinno++) {
		if(!(mask & 1))
			continue;

		int chars = 0;

		char port;
		/* This is FTDI's naming scheme.
		 * probably 'D' is for data and 'C' for control
		 */
		if(pinno < 8)
			port = 'D';
		else
			port = 'C';

		if(str[0] == 0)
			fmt = "%c%cBUS%d%n";
		else
			fmt = ", %c%cBUS%d%n";

		snprintf(&str[n], sizeof(str) - n, fmt, interface, port, pinno, &chars);
		n += chars;
	}

	return str;
}

/*
 * output function, to save if(vebose>level)-constructs. Also prefixes output
 * with "avrftdi function-name(line-number):" to identify were messages came
 * from.
 * This function is the backend of the log_*-macros, but it can be used
 * directly.
 */
void avrftdi_log(int level, const char * func, int line,
		const char * fmt, ...) {
	static int skip_prefix = 0;
	const char *p = fmt;
	va_list ap;

	if(verbose >= level)
	{
		if(!skip_prefix)
		{
			switch(level) {
				case ERR: avrdude_message(MSG_INFO, "E "); break;
				case WARN:  avrdude_message(MSG_INFO, "W "); break;
				case INFO:  avrdude_message(MSG_INFO, "I "); break;
				case DEBUG: avrdude_message(MSG_INFO, "D "); break;
				case TRACE: avrdude_message(MSG_INFO, "T "); break;
				default: avrdude_message(MSG_INFO, "  "); break;
			}
			avrdude_message(MSG_INFO, "%s(%d): ", func, line);
		}
		va_start(ap, fmt);
		vfprintf(stderr, fmt, ap);
		va_end(ap);
	}

	skip_prefix = 1;
	while(*p++)
		if(*p == '\n' && !(*(p+1)))
			skip_prefix = 0;
}

/*
 * helper function to print a binary buffer *buf of size len. Begin and end of
 * the dump are enclosed in the string contained in *desc. Offset denotes the
 * number of bytes which are printed on the first line (may be 0). After that
 * width bytes are printed on each line
 */
static void buf_dump(const unsigned char *buf, int len, char *desc,
		     int offset, int width)
{
	int i;
	avrdude_message(MSG_INFO, "%s begin:\n", desc);
	for (i = 0; i < offset; i++)
		avrdude_message(MSG_INFO, "%02x ", buf[i]);
	avrdude_message(MSG_INFO, "\n");
	for (i++; i <= len; i++) {
		avrdude_message(MSG_INFO, "%02x ", buf[i-1]);
		if((i-offset) != 0 && (i-offset)%width == 0)
		    avrdude_message(MSG_INFO, "\n");
	}
	avrdude_message(MSG_INFO, "%s end\n", desc);
}

/*
 * calculates the so-called 'divisor'-value from a given frequency.
 * the divisor is sent to the chip.
 */
static int set_frequency(avrftdi_t* ftdi, uint32_t freq)
{
	int32_t divisor;
	uint8_t buf[3];

	/* divisor on 6000000 / freq - 1 */
	divisor = (6000000 / freq) - 1;
	if (divisor < 0) {
		log_warn("Frequency too high (%u > 6 MHz)\n", freq);
		log_warn("Resetting Frequency to 6MHz\n");
		divisor = 0;
	}

	if (divisor > 65535) {
		log_warn("Frequency too low (%u < 91.553 Hz)\n", freq);
		log_warn("Resetting Frequency to 91.553Hz\n");
		divisor = 65535;
	}

	log_info("Using frequency: %d\n", 6000000/(divisor+1));
	log_info("Clock divisor: 0x%04x\n", divisor);

	buf[0] = TCK_DIVISOR;
	buf[1] = (uint8_t)(divisor & 0xff);
	buf[2] = (uint8_t)((divisor >> 8) & 0xff);

	E(ftdi_write_data(ftdi->ftdic, buf, 3) < 0, ftdi->ftdic);

	return 0;
}

/*
 * This function sets or clears any pin, except SCK, MISO and MOSI. Depending
 * on the pin configuration, a non-zero value sets the pin in the 'active'
 * state (high active, low active) and a zero value sets the pin in the
 * inactive state.
 * Because we configured the pin direction mask earlier, nothing bad can happen
 * here.
 */
static int set_pin(const PROGRAMMER *pgm, int pinfunc, int value) {
	avrftdi_t* pdata = to_pdata(pgm);
	struct pindef_t pin = pgm->pin[pinfunc];
	
	if (pin.mask[0] == 0) {
		// ignore not defined pins (might be the led or vcc or buff if not needed)
		return 0;
	}

	log_debug("Setting pin %s (%s) as %s: %s (%s active)\n",
	          pinmask_to_str(pin.mask), ftdi_pin_name(pdata, pin),
						avr_pin_name(pinfunc),
	          (value) ? "high" : "low", (pin.inverse[0]) ? "low" : "high");

	pdata->pin_value = SET_BITS_0(pdata->pin_value, pgm, pinfunc, value);

	return write_flush(pdata);
}

/*
 * Mandatory callbacks which boil down to GPIO.
 */
static int set_led_pgm(const PROGRAMMER *pgm, int value) {
	return set_pin(pgm, PIN_LED_PGM, value);
}

static int set_led_rdy(const PROGRAMMER *pgm, int value) {
	return set_pin(pgm, PIN_LED_RDY, value);
}

static int set_led_err(const PROGRAMMER *pgm, int value) {
	return set_pin(pgm, PIN_LED_ERR, value);
}

static int set_led_vfy(const PROGRAMMER *pgm, int value) {
	return set_pin(pgm, PIN_LED_VFY, value);
}

static void avrftdi_enable(PROGRAMMER *pgm, const AVRPART *p) {
	set_pin(pgm, PPI_AVR_BUFF, ON);

	// Switch to TPI initialisation in avrftdi_tpi.c
	if(p->flags & AVRPART_HAS_TPI)
          avrftdi_tpi_initpgm(pgm);
}

static void avrftdi_disable(const PROGRAMMER *pgm) {
	set_pin(pgm, PPI_AVR_BUFF, OFF);
}

static void avrftdi_powerup(const PROGRAMMER *pgm) {
	set_pin(pgm, PPI_AVR_VCC, ON);
}

static void avrftdi_powerdown(const PROGRAMMER *pgm) {
	set_pin(pgm, PPI_AVR_VCC, OFF);
}

static inline int set_data(const PROGRAMMER *pgm, unsigned char *buf, unsigned char data, bool read_data) {
	int j;
	int buf_pos = 0;
	unsigned char bit = 0x80;
	avrftdi_t* pdata = to_pdata(pgm);

	for (j=0; j<8; j++) {
		pdata->pin_value = SET_BITS_0(pdata->pin_value,pgm,PIN_AVR_MOSI,data & bit);
		pdata->pin_value = SET_BITS_0(pdata->pin_value,pgm,PIN_AVR_SCK,0);
		buf[buf_pos++] = SET_BITS_LOW;
		buf[buf_pos++] = (pdata->pin_value) & 0xff;
		buf[buf_pos++] = (pdata->pin_direction) & 0xff;
		buf[buf_pos++] = SET_BITS_HIGH;
		buf[buf_pos++] = ((pdata->pin_value) >> 8) & 0xff;
		buf[buf_pos++] = ((pdata->pin_direction) >> 8) & 0xff;

		pdata->pin_value = SET_BITS_0(pdata->pin_value,pgm,PIN_AVR_SCK,1);
		buf[buf_pos++] = SET_BITS_LOW;
		buf[buf_pos++] = (pdata->pin_value) & 0xff;
		buf[buf_pos++] = (pdata->pin_direction) & 0xff;
		buf[buf_pos++] = SET_BITS_HIGH;
		buf[buf_pos++] = ((pdata->pin_value) >> 8) & 0xff;
		buf[buf_pos++] = ((pdata->pin_direction) >> 8) & 0xff;

		if (read_data) {
			buf[buf_pos++] = GET_BITS_LOW;
			buf[buf_pos++] = GET_BITS_HIGH;
		}

		bit >>= 1;
	}
	return buf_pos;
}

static inline unsigned char extract_data(const PROGRAMMER *pgm, unsigned char *buf, int offset) {
	int j;
	unsigned char bit = 0x80;
	unsigned char r = 0;

	buf += offset * 16; // 2 bytes per bit, 8 bits
	for (j=0; j<8; j++) {
		uint16_t in = buf[0] | (buf[1] << 8);
		if (GET_BITS_0(in,pgm,PIN_AVR_MISO)) {
			r |= bit;
		}
		buf += 2; // 2 bytes per input
		bit >>= 1;
	}
	return r;
}


static int avrftdi_transmit_bb(const PROGRAMMER *pgm, unsigned char mode, const unsigned char *buf,
			    unsigned char *data, int buf_size)
{
	size_t remaining = buf_size;
	size_t written = 0;
	avrftdi_t* pdata = to_pdata(pgm);
	size_t blocksize = pdata->rx_buffer_size/2; // we are reading 2 bytes per data byte

	// determine a maximum size of data block
	size_t max_size = MIN(pdata->ftdic->max_packet_size, (unsigned int) pdata->tx_buffer_size);
	// select block size so that resulting commands does not exceed max_size if possible
	blocksize = MAX(1,(max_size-7)/((8*2*6)+(8*1*2)));
	//avrdude_message(MSG_INFO, "blocksize %d \n",blocksize);

	unsigned char* send_buffer = alloca((8 * 2 * 6) * blocksize + (8 * 1 * 2) * blocksize + 7);
	unsigned char* recv_buffer = alloca(2 * 16 * blocksize);

	while(remaining)
	{

		size_t transfer_size = (remaining > blocksize) ? blocksize : remaining;

		// (8*2) outputs per data byte, 6 transmit bytes per output (SET_BITS_LOW/HIGH),
		// (8*1) inputs per data byte,  2 transmit bytes per input  (GET_BITS_LOW/HIGH),
		// 1x SEND_IMMEDIATE
		int len = 0;
		
		for(size_t i = 0 ; i < transfer_size; i++) {
		    len += set_data(pgm, send_buffer + len, buf[written+i], (mode & MPSSE_DO_READ) != 0);
		}

		pdata->pin_value = SET_BITS_0(pdata->pin_value,pgm,PIN_AVR_SCK,0);
		send_buffer[len++] = SET_BITS_LOW;
		send_buffer[len++] = (pdata->pin_value) & 0xff;
		send_buffer[len++] = (pdata->pin_direction) & 0xff;
		send_buffer[len++] = SET_BITS_HIGH;
		send_buffer[len++] = ((pdata->pin_value) >> 8) & 0xff;
		send_buffer[len++] = ((pdata->pin_direction) >> 8) & 0xff;

		send_buffer[len++] = SEND_IMMEDIATE;

		E(ftdi_write_data(pdata->ftdic, send_buffer, len) != len, pdata->ftdic);
		if (mode & MPSSE_DO_READ) {
			int n;
			size_t k = 0;
			do {
				n = ftdi_read_data(pdata->ftdic, &recv_buffer[k], 2*16*transfer_size - k);
				E(n < 0, pdata->ftdic);
				k += n;
			} while (k < transfer_size);

			for(size_t i = 0 ; i< transfer_size; i++) {
			    data[written + i] = extract_data(pgm, recv_buffer, i);
			}
		}
		
		written += transfer_size;
		remaining -= transfer_size;
	}
	
	return written;
}

/* Send 'buf_size' bytes from 'cmd' to device and return data from device in
 * buffer 'data'.
 * Write is only performed when mode contains MPSSE_DO_WRITE.
 * Read is only performed when mode contains MPSSE_DO_WRITE and MPSSE_DO_READ.
 */
static int avrftdi_transmit_mpsse(avrftdi_t* pdata, unsigned char mode, const unsigned char *buf,
			    unsigned char *data, int buf_size)
{
	size_t blocksize;
	size_t remaining = buf_size;
	size_t written = 0;
	
	unsigned char cmd[3];
//	unsigned char si = SEND_IMMEDIATE;

	cmd[0] = mode | MPSSE_WRITE_NEG;
	cmd[1] = ((buf_size - 1) & 0xff);
	cmd[2] = (((buf_size - 1) >> 8) & 0xff);

	//if we are not reading back, we can just write the data out
	if(!(mode & MPSSE_DO_READ))
		blocksize = buf_size;
	else
		blocksize = pdata->rx_buffer_size;

	E(ftdi_write_data(pdata->ftdic, cmd, sizeof(cmd)) != sizeof(cmd), pdata->ftdic);

	while(remaining)
	{
		size_t transfer_size = (remaining > blocksize) ? blocksize : remaining;

		E((size_t) ftdi_write_data(pdata->ftdic, (unsigned char*)&buf[written], transfer_size) != transfer_size, pdata->ftdic);
#if 0
		if(remaining < blocksize)
			E(ftdi_write_data(pdata->ftdic, &si, sizeof(si)) != sizeof(si), pdata->ftdic);
#endif

		if (mode & MPSSE_DO_READ) {
			int n;
			size_t k = 0;
			do {
				n = ftdi_read_data(pdata->ftdic, &data[written + k], transfer_size - k);
				E(n < 0, pdata->ftdic);
				k += n;
			} while (k < transfer_size);

		}
		
		written += transfer_size;
		remaining -= transfer_size;
	}
	
	return written;
}

static inline int avrftdi_transmit(const PROGRAMMER *pgm, unsigned char mode, const unsigned char *buf,
			    unsigned char *data, int buf_size)
{
	avrftdi_t* pdata = to_pdata(pgm);
	if (pdata->use_bitbanging)
		return avrftdi_transmit_bb(pgm, mode, buf, data, buf_size);
	else
		return avrftdi_transmit_mpsse(pdata, mode, buf, data, buf_size);
}

static int write_flush(avrftdi_t* pdata)
{
	unsigned char buf[6];

	log_debug("Setting pin direction (0x%04x) and value (0x%04x)\n",
	          pdata->pin_direction, pdata->pin_value);

	buf[0] = SET_BITS_LOW;
	buf[1] = (pdata->pin_value) & 0xff;
	buf[2] = (pdata->pin_direction) & 0xff;
	buf[3] = SET_BITS_HIGH;
	buf[4] = ((pdata->pin_value) >> 8) & 0xff;
	buf[5] = ((pdata->pin_direction) >> 8) & 0xff;

	E(ftdi_write_data(pdata->ftdic, buf, 6) != 6, pdata->ftdic);

	log_trace("Set pins command: %02x %02x %02x %02x %02x %02x\n",
	          buf[0], buf[1], buf[2], buf[3], buf[4], buf[5]);

	/* we need to flush here, because set_pin is used as reset.
	 * if we want to sleep reset periods, we must be certain the
	 * avr has got the reset signal when we start sleeping.
	 * (it may be stuck in the USB stack or some USB hub)
	 *
	 * Add.: purge does NOT flush. It clears. Also, it is unknown, when the purge
	 * command actually arrives at the chip.
	 * Use read pin status command as sync.
	 */
	//E(ftdi_usb_purge_buffers(pdata->ftdic), pdata->ftdic);

	unsigned char cmd[] = { GET_BITS_LOW, SEND_IMMEDIATE };
	E(ftdi_write_data(pdata->ftdic, cmd, sizeof(cmd)) != sizeof(cmd), pdata->ftdic);
	
	int num = 0;
	do
	{
		int n = ftdi_read_data(pdata->ftdic, buf, sizeof(buf));
		if(n > 0)
			num += n;
		E(n < 0, pdata->ftdic);
	} while(num < 1);
	
	if(num > 1)
		log_warn("Read %d extra bytes\n", num-1);

	return 0;

}

static int avrftdi_check_pins_bb(const PROGRAMMER *pgm, bool output) {
	int pin;

	/* pin checklist. */
	struct pin_checklist_t pin_checklist[N_PINS];

	avrftdi_t* pdata = to_pdata(pgm);

	/* value for 8/12/16 bit wide interface */
	int valid_mask = ((1 << pdata->pin_limit) - 1);

	log_debug("Using valid mask bitbanging: 0x%08x\n", valid_mask);
	static struct pindef_t valid_pins;
	valid_pins.mask[0] = valid_mask;
	valid_pins.inverse[0] = valid_mask ;

	/* build pin checklist */
	for(pin = 0; pin < N_PINS; ++pin) {
		pin_checklist[pin].pinname = pin;
		pin_checklist[pin].mandatory = 0;
		pin_checklist[pin].valid_pins = &valid_pins;
	}

	/* assumes all checklists above have same number of entries */
	return pins_check(pgm, pin_checklist, N_PINS, output);
}

static int avrftdi_check_pins_mpsse(const PROGRAMMER *pgm, bool output) {
	int pin;

	/* pin checklist. */
	struct pin_checklist_t pin_checklist[N_PINS];

	avrftdi_t* pdata = to_pdata(pgm);

	/* SCK/MOSI/MISO are fixed and not invertible?*/
	/* TODO: inverted SCK/MISO/MOSI */
	static const struct pindef_t valid_pins_SCK  = {{0x01},{0x00}} ;
	static const struct pindef_t valid_pins_MOSI = {{0x02},{0x00}} ;
	static const struct pindef_t valid_pins_MISO = {{0x04},{0x00}} ;

	/* value for 8/12/16 bit wide interface for other pins */
	int valid_mask = ((1 << pdata->pin_limit) - 1);
	/* mask out SCK/MISO/MOSI */
	valid_mask &= ~((1 << FTDI_SCK) | (1 << FTDI_MOSI) | (1 << FTDI_MISO));

	log_debug("Using valid mask mpsse: 0x%08x\n", valid_mask);
	static struct pindef_t valid_pins_others;
	valid_pins_others.mask[0] = valid_mask;
	valid_pins_others.inverse[0] = valid_mask ;

	/* build pin checklist */
	for(pin = 0; pin < N_PINS; ++pin) {
		pin_checklist[pin].pinname = pin;
		pin_checklist[pin].mandatory = 0;
		pin_checklist[pin].valid_pins = &valid_pins_others;
	}

	/* now set mpsse specific pins */
	pin_checklist[PIN_AVR_SCK].mandatory = 1;
	pin_checklist[PIN_AVR_SCK].valid_pins = &valid_pins_SCK;
	pin_checklist[PIN_AVR_MOSI].mandatory = 1;
	pin_checklist[PIN_AVR_MOSI].valid_pins = &valid_pins_MOSI;
	pin_checklist[PIN_AVR_MISO].mandatory = 1;
	pin_checklist[PIN_AVR_MISO].valid_pins = &valid_pins_MISO;
	pin_checklist[PIN_AVR_RESET].mandatory = 1;

	/* assumes all checklists above have same number of entries */
	return pins_check(pgm, pin_checklist, N_PINS, output);
}

static int avrftdi_pin_setup(const PROGRAMMER *pgm) {
	int pin;

	/*************
	 * pin setup *
	 *************/

	avrftdi_t* pdata = to_pdata(pgm);

	bool pin_check_mpsse = (0 == avrftdi_check_pins_mpsse(pgm, verbose>3));

	bool pin_check_bitbanging = (0 == avrftdi_check_pins_bb(pgm, verbose>3));

	if (!pin_check_mpsse && !pin_check_bitbanging) {
		log_err("No valid pin configuration found.\n");
		avrftdi_check_pins_bb(pgm, true);
		log_err("Pin configuration for FTDI MPSSE must be:\n");
		log_err("%s: 0, %s: 1, %s: 2 (is: %s, %s, %s)\n", avr_pin_name(PIN_AVR_SCK),
		         avr_pin_name(PIN_AVR_MOSI), avr_pin_name(PIN_AVR_MISO),
						 pins_to_str(&pgm->pin[PIN_AVR_SCK]),
						 pins_to_str(&pgm->pin[PIN_AVR_MOSI]),
						 pins_to_str(&pgm->pin[PIN_AVR_MISO]));
		log_err("If other pin configuration is used, fallback to slower bitbanging mode is used.\n");

		return -1;
	}

	pdata->use_bitbanging = !pin_check_mpsse;
	if (pdata->use_bitbanging) log_info("Because of pin configuration fallback to bitbanging mode.\n");

	/*
	 * TODO: No need to fail for a wrongly configured led or something.
	 * Maybe we should only fail for SCK; MISO, MOSI, RST (and probably
	 * VCC and BUFF).
	 */

	/* everything is an output, except MISO */
	for(pin = 0; pin < N_PINS; ++pin) {
		pdata->pin_direction |= pgm->pin[pin].mask[0];
		pdata->pin_value = SET_BITS_0(pdata->pin_value, pgm, pin, OFF);
	}
	pdata->pin_direction &= ~pgm->pin[PIN_AVR_MISO].mask[0];

	for(pin = PIN_LED_ERR; pin < N_PINS; ++pin) {
		pdata->led_mask |= pgm->pin[pin].mask[0];
	}


	log_info("Pin direction mask: %04x\n", pdata->pin_direction);
	log_info("Pin value mask: %04x\n", pdata->pin_value);

	return 0;
}

static int avrftdi_open(PROGRAMMER *pgm, const char *port) {
	int vid, pid, interface, index, err;
	const char *serial, *desc;
	
	avrftdi_t* pdata = to_pdata(pgm);

	/************************
	 * parameter validation *
	 ************************/

	/* use vid/pid in following priority: config,
	 * defaults. cmd-line is currently not supported */
	
	if (pgm->usbvid)
		vid = pgm->usbvid;
	else
		vid = USB_VENDOR_FTDI;

	LNODEID usbpid = lfirst(pgm->usbpid);
	if (usbpid) {
		pid = *(int *)(ldata(usbpid));
		if (lnext(usbpid))
			avrdude_message(MSG_INFO, "%s: Warning: using PID 0x%04x, ignoring remaining PIDs in list\n",
                                        progname, pid);
	} else
		pid = USB_DEVICE_FT2232;

	if (0 == pgm->usbsn[0]) /* we don't care about SN. Use first avail. */
		serial = NULL;
	else
		serial = pgm->usbsn;

	/* not used yet, but i put them here, just in case someone does needs or
	 * wants to implement this.
	 */
	desc = NULL;
	index = 0;

	if (pgm->usbdev[0] == 'a' || pgm->usbdev[0] == 'A')
		interface = INTERFACE_A;
	else if (pgm->usbdev[0] == 'b' || pgm->usbdev[0] == 'B')
		interface = INTERFACE_B;
	else {
		log_warn("Invalid interface '%s'. Setting to Interface A\n", pgm->usbdev);
		interface = INTERFACE_A;
	}

	/****************
	 * Device setup *
	 ****************/

	E(ftdi_set_interface(pdata->ftdic, interface) < 0, pdata->ftdic);
	
	err = ftdi_usb_open_desc_index(pdata->ftdic, vid, pid, desc, serial, index);
	if(err) {
		log_err("Error %d occurred: %s\n", err, ftdi_get_error_string(pdata->ftdic));
		//stupid hack, because avrdude calls pgm->close() even when pgm->open() fails
		//and usb_dev is initialized to the last usb device from probing
		pdata->ftdic->usb_dev = NULL;
		return err;
	} else {
		log_info("Using device VID:PID %04x:%04x and SN '%s' on interface %c.\n",
		         vid, pid, serial, INTERFACE_A == interface? 'A': 'B');
	}
	
	ftdi_set_latency_timer(pdata->ftdic, 1);
	//ftdi_write_data_set_chunksize(pdata->ftdic, 16);
	//ftdi_read_data_set_chunksize(pdata->ftdic, 16);

	/* set SPI mode */
	E(ftdi_set_bitmode(pdata->ftdic, 0, BITMODE_RESET) < 0, pdata->ftdic);
	E(ftdi_set_bitmode(pdata->ftdic, pdata->pin_direction & 0xff, BITMODE_MPSSE) < 0, pdata->ftdic);
#ifdef HAVE_FTDI_TCIOFLUSH
	E(ftdi_tcioflush(pdata->ftdic), pdata->ftdic);
#else
	E(ftdi_usb_purge_buffers(pdata->ftdic), pdata->ftdic);
#endif

	write_flush(pdata);

	if (pgm->baudrate) {
		set_frequency(pdata, pgm->baudrate);
	} else if(pgm->bitclock) {
		set_frequency(pdata, (uint32_t)(1.0f/pgm->bitclock));
	} else {
		set_frequency(pdata, pgm->baudrate ? pgm->baudrate : 150000);
	}

	/* set pin limit depending on chip type */
	switch(pdata->ftdic->type) {
		case TYPE_AM:
		case TYPE_BM:
		case TYPE_R:
			log_err("Found unsupported device type AM, BM or R. avrftdi ");
			log_err("cannot work with your chip. Try the 'synbb' programmer.\n");
			return -1;
		case TYPE_2232C:
			pdata->pin_limit = 12;
			pdata->rx_buffer_size = 384;
			pdata->tx_buffer_size = 128;
			break;
		case TYPE_2232H:
			pdata->pin_limit = 16;
			pdata->rx_buffer_size = 4096;
			pdata->tx_buffer_size = 4096;
			break;
#ifdef HAVE_LIBFTDI_TYPE_232H
		case TYPE_232H:
			pdata->pin_limit = 16;
			pdata->rx_buffer_size = 1024;
			pdata->tx_buffer_size = 1024;
			break;
#else
#ifdef _MSC_VER
#pragma message("No support for 232H, use a newer libftdi, version >= 0.20")
#else
#warning No support for 232H, use a newer libftdi, version >= 0.20
#endif
#endif
		case TYPE_4232H:
			pdata->pin_limit = 8;
			pdata->rx_buffer_size = 2048;
			pdata->tx_buffer_size = 2048;
			break;
		default:
			log_warn("Found unknown device %x. I will do my ", pdata->ftdic->type);
			log_warn("best to work with it, but no guarantees ...\n");
			pdata->pin_limit = 8;
			pdata->rx_buffer_size = pdata->ftdic->max_packet_size;
			pdata->tx_buffer_size = pdata->ftdic->max_packet_size;
			break;
	}

	if(avrftdi_pin_setup(pgm))
		return -1;

	/**********************************************
	 * set the ready LED and set our direction up *
	 **********************************************/

	set_led_rdy(pgm,0);
	set_led_pgm(pgm,1);

	return 0;
}

static void avrftdi_close(PROGRAMMER * pgm)
{
	avrftdi_t* pdata = to_pdata(pgm);

	if(pdata->ftdic->usb_dev) {
		set_pin(pgm, PIN_AVR_RESET, ON);

		/* Stop driving the pins - except for the LEDs */
		log_info("LED Mask=0x%04x value =0x%04x &=0x%04x\n",
				pdata->led_mask, pdata->pin_value, pdata->led_mask & pdata->pin_value);

		pdata->pin_direction = pdata->led_mask;
		pdata->pin_value &= pdata->led_mask;
		write_flush(pdata);
		/* reset state recommended by FTDI */
		ftdi_set_bitmode(pdata->ftdic, 0, BITMODE_RESET);
		E_VOID(ftdi_usb_close(pdata->ftdic), pdata->ftdic);
	}

	return;
}

static int avrftdi_initialize(const PROGRAMMER *pgm, const AVRPART *p) {
	avrftdi_powerup(pgm);

	if(p->flags & AVRPART_HAS_TPI)
	{
		/* see avrftdi_tpi.c */
		avrftdi_tpi_initialize(pgm, p);
	}
	else
	{
		set_pin(pgm, PIN_AVR_RESET, OFF);
		set_pin(pgm, PIN_AVR_SCK, OFF);
		/*use speed optimization with CAUTION*/
		usleep(20 * 1000);

		/* giving rst-pulse of at least 2 avr-clock-cycles, for
		 * security (2us @ 1MHz) */
		set_pin(pgm, PIN_AVR_RESET, ON);
		usleep(20 * 1000);

		/*setting rst back to 0 */
		set_pin(pgm, PIN_AVR_RESET, OFF);
		/*wait at least 20ms before issuing spi commands to avr */
		usleep(20 * 1000);
	}

	return pgm->program_enable(pgm, p);
}

static void avrftdi_display(const PROGRAMMER *pgm, const char *p) {
	// print the full pin definitions as in ft245r ?
	return;
}


static int avrftdi_cmd(const PROGRAMMER *pgm, const unsigned char *cmd, unsigned char *res) {
	return avrftdi_transmit(pgm, MPSSE_DO_READ | MPSSE_DO_WRITE, cmd, res, 4);
}


static int avrftdi_program_enable(const PROGRAMMER *pgm, const AVRPART *p) {
	int i;
	unsigned char buf[4];

	memset(buf, 0, sizeof(buf));

	if (p->op[AVR_OP_PGM_ENABLE] == NULL) {
		log_err("AVR_OP_PGM_ENABLE command not defined for %s\n", p->desc);
		return -1;
	}

	avr_set_bits(p->op[AVR_OP_PGM_ENABLE], buf);

	for(i = 0; i < 4; i++) {
		pgm->cmd(pgm, buf, buf);
		if (buf[p->pollindex-1] != p->pollvalue) {
			log_warn("Program enable command not successful. Retrying.\n");
			set_pin(pgm, PIN_AVR_RESET, ON);
			usleep(20);
			set_pin(pgm, PIN_AVR_RESET, OFF);
			avr_set_bits(p->op[AVR_OP_PGM_ENABLE], buf);
		} else
			return 0;
	}

	log_err("Device is not responding to program enable. Check connection.\n");

	return -1;
}


static int avrftdi_chip_erase(const PROGRAMMER *pgm, const AVRPART *p) {
	unsigned char cmd[4];
	unsigned char res[4];

	if (p->op[AVR_OP_CHIP_ERASE] == NULL) {
		log_err("AVR_OP_CHIP_ERASE command not defined for %s\n", p->desc);
		return -1;
	}

	memset(cmd, 0, sizeof(cmd));

	avr_set_bits(p->op[AVR_OP_CHIP_ERASE], cmd);
	pgm->cmd(pgm, cmd, res);
	usleep(p->chip_erase_delay);
	pgm->initialize(pgm, p);

	return 0;
}


/* Load extended address byte command */
static int
avrftdi_lext(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m, unsigned int address) {
	/* nothing to do if load extended address command unavailable */
	if(m->op[AVR_OP_LOAD_EXT_ADDR] == NULL)
		return 0;

	avrftdi_t *pdata = to_pdata(pgm);
	unsigned char buf[] = { 0x00, 0x00, 0x00, 0x00 };

	/* only send load extended address command if high byte changed */
	if(pdata->lext_byte == (uint8_t) (address>>16))
		return 0;

	pdata->lext_byte = (uint8_t) (address>>16);

	avr_set_bits(m->op[AVR_OP_LOAD_EXT_ADDR], buf);
	avr_set_addr(m->op[AVR_OP_LOAD_EXT_ADDR], buf, address);

	if(verbose > TRACE)
		buf_dump(buf, sizeof(buf),
			 "load extended address command", 0, 16 * 3);

	if (0 > avrftdi_transmit(pgm, MPSSE_DO_WRITE, buf, buf, 4))
		return -1;
	
	return 0;
}

static int avrftdi_eeprom_write(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
		unsigned int page_size, unsigned int addr, unsigned int len)
{
	unsigned char cmd[] = { 0x00, 0x00, 0x00, 0x00 };
	unsigned char *data = &m->buf[addr];
	unsigned int add;

	avr_set_bits(m->op[AVR_OP_WRITE], cmd);

	for (add = addr; add < addr + len; add++)
	{
		avr_set_addr(m->op[AVR_OP_WRITE], cmd, add);
		avr_set_input(m->op[AVR_OP_WRITE], cmd, *data++);

		if (0 > avrftdi_transmit(pgm, MPSSE_DO_WRITE, cmd, cmd, 4))
		    return -1;
		usleep((m->max_write_delay));

	}
	return len;
}

static int avrftdi_eeprom_read(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
		unsigned int page_size, unsigned int addr, unsigned int len)
{
	unsigned char cmd[4];
	unsigned int add;
	unsigned char* buffer = alloca(len);
	unsigned char* bufptr = buffer;

	memset(buffer, 0, len);

	for (add = addr; add < addr + len; add++)
	{
		memset(cmd, 0, sizeof(cmd));
		avr_set_bits(m->op[AVR_OP_READ], cmd);
		avr_set_addr(m->op[AVR_OP_READ], cmd, add);

		if (0 > avrftdi_transmit(pgm, MPSSE_DO_READ | MPSSE_DO_WRITE, cmd, cmd, 4))
			return -1;

		avr_get_output(m->op[AVR_OP_READ], cmd, bufptr++);
	}

	memcpy(m->buf + addr, buffer, len);
	return len;
}

static int avrftdi_flash_write(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
		unsigned int page_size, unsigned int addr, unsigned int len)
{
	unsigned int word;
	unsigned int poll_index;

	unsigned char poll_byte;
	unsigned char *buffer = &m->buf[addr];
	unsigned int buf_size = 4 * len + 4;
	unsigned char* buf = alloca(buf_size);
	unsigned char* bufptr = buf;

	memset(buf, 0, buf_size);

	/* pre-check opcodes */
	if (m->op[AVR_OP_LOADPAGE_LO] == NULL) {
		log_err("AVR_OP_LOADPAGE_LO command not defined for %s\n", p->desc);
		return -1;
	}
	if (m->op[AVR_OP_LOADPAGE_HI] == NULL) {
		log_err("AVR_OP_LOADPAGE_HI command not defined for %s\n", p->desc);
		return -1;
	}

	if(page_size != (unsigned int) m->page_size) {
		log_warn("Parameter page_size is %d, ", page_size);
		log_warn("but m->page_size is %d. Using the latter.\n", m->page_size);
	}

	page_size = m->page_size;

	/* on large-flash devices > 128k issue extended address command when needed */
	if(avrftdi_lext(pgm, p, m, addr/2) < 0)
		return -1;
	
	/* prepare the command stream for the whole page */
	/* addr is in bytes, but we program in words. */
	for(word = addr/2; word < (len + addr)/2; word++)
	{
		log_debug("-< bytes = %d of %d\n", word * 2, len + addr);

		/*setting word*/
		avr_set_bits(m->op[AVR_OP_LOADPAGE_LO], bufptr);
		/* here is the second byte increment, just if you're wondering */
		avr_set_addr(m->op[AVR_OP_LOADPAGE_LO], bufptr, word);
		avr_set_input(m->op[AVR_OP_LOADPAGE_LO], bufptr, *buffer++);
		bufptr += 4;
		avr_set_bits(m->op[AVR_OP_LOADPAGE_HI], bufptr);
		avr_set_addr(m->op[AVR_OP_LOADPAGE_HI], bufptr, word);
		avr_set_input(m->op[AVR_OP_LOADPAGE_HI], bufptr, *buffer++);
		bufptr += 4;
	}

	/* issue write page command, if available */
	if (m->op[AVR_OP_WRITEPAGE] == NULL) {
		log_err("AVR_OP_WRITEPAGE command not defined for %s\n", p->desc);
		return -1;
	} else {
		avr_set_bits(m->op[AVR_OP_WRITEPAGE], bufptr);
		/* setting page address highbyte */
		avr_set_addr(m->op[AVR_OP_WRITEPAGE],
					 bufptr, addr/2);
		bufptr += 4;
	}

	/* find a poll byte. We cannot poll a value of 0xff, so look
	 * for a value != 0xff
	 */
	for(poll_index = addr+len-1; poll_index+1 > addr; poll_index--)
		if(m->buf[poll_index] != 0xff)
			break;

	if(poll_index+1 > addr) {
		buf_size = bufptr - buf;

		if(verbose > TRACE)
			buf_dump(buf, buf_size, "command buffer", 0, 16*2);

		log_info("Transmitting buffer of size: %d\n", buf_size);
		if (0 > avrftdi_transmit(pgm, MPSSE_DO_WRITE, buf, buf, buf_size))
			return -1;

		bufptr = buf;

		log_info("Using m->buf[%d] = 0x%02x as polling value ", poll_index,
		         m->buf[poll_index]);
		/* poll page write ready */
		do {
			log_info(".");

			pgm->read_byte(pgm, p, m, poll_index, &poll_byte);
		} while (m->buf[poll_index] != poll_byte);

		log_info("\n");
	}
	else
	{
		log_warn("Skipping empty page (containing only 0xff bytes)\n");
		/* TODO sync write */
		/* sleep */
		usleep((m->max_write_delay));
	}

	return len;
}

/*
 *Reading from flash
 */
static int avrftdi_flash_read(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
		unsigned int page_size, unsigned int addr, unsigned int len)
{
	OPCODE * readop;

	unsigned int buf_size = 4 * len + 4;
	unsigned char* o_buf = alloca(buf_size);
	unsigned char* i_buf = alloca(buf_size);


	memset(o_buf, 0, buf_size);
	memset(i_buf, 0, buf_size);

	/* pre-check opcodes */
	if (m->op[AVR_OP_READ_LO] == NULL) {
		log_err("AVR_OP_READ_LO command not defined for %s\n", p->desc);
		return -1;
	}
	if (m->op[AVR_OP_READ_HI] == NULL) {
		log_err("AVR_OP_READ_HI command not defined for %s\n", p->desc);
		return -1;
	}
	
	if(avrftdi_lext(pgm, p, m, addr/2) < 0)
		return -1;
	
	/* word addressing! */
	for(unsigned int word = addr/2, index = 0; word < (addr + len)/2; word++)
	{
		/* one byte is transferred via a 4-byte opcode.
		 * TODO: reduce magic numbers
		 */
		avr_set_bits(m->op[AVR_OP_READ_LO], &o_buf[index*4]);
		avr_set_addr(m->op[AVR_OP_READ_LO], &o_buf[index*4], word);
		index++;
		avr_set_bits(m->op[AVR_OP_READ_HI], &o_buf[index*4]);
		avr_set_addr(m->op[AVR_OP_READ_HI], &o_buf[index*4], word);
		index++;
	}

	/* transmit,
	 * if there was an error, we did not see, memory validation will
	 * subsequently fail.
	 */
	if(verbose > TRACE) {
		buf_dump(o_buf, sizeof(o_buf), "o_buf", 0, 32);
	}

	if (0 > avrftdi_transmit(pgm, MPSSE_DO_READ | MPSSE_DO_WRITE, o_buf, i_buf, len * 4))
		return -1;

	if(verbose > TRACE) {
		buf_dump(i_buf, sizeof(i_buf), "i_buf", 0, 32);
	}

	memset(&m->buf[addr], 0, page_size);

	/* every (read) op is 4 bytes in size and yields one byte of memory data */
	for(unsigned int byte = 0; byte < page_size; byte++) {
		if(byte & 1)
			readop = m->op[AVR_OP_READ_HI];
		else
			readop = m->op[AVR_OP_READ_LO];

		/* take 4 bytes and put the memory byte in the buffer at
		 * offset addr + offset of the current byte
		 */
		avr_get_output(readop, &i_buf[byte*4], &m->buf[addr+byte]);
	}

	if(verbose > TRACE)
		buf_dump(&m->buf[addr], page_size, "page:", 0, 32);

	return len;
}

static int avrftdi_paged_write(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
		unsigned int page_size, unsigned int addr, unsigned int n_bytes)
{
	if (strcmp(m->desc, "flash") == 0)
		return avrftdi_flash_write(pgm, p, m, page_size, addr, n_bytes);
	else if (strcmp(m->desc, "eeprom") == 0)
		return avrftdi_eeprom_write(pgm, p, m, page_size, addr, n_bytes);
	else
		return -2;
}

static int avrftdi_paged_load(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m,
		unsigned int page_size, unsigned int addr, unsigned int n_bytes)
{
	if (strcmp(m->desc, "flash") == 0)
		return avrftdi_flash_read(pgm, p, m, page_size, addr, n_bytes);
	else if(strcmp(m->desc, "eeprom") == 0)
		return avrftdi_eeprom_read(pgm, p, m, page_size, addr, n_bytes);
	else
		return -2;
}

static void
avrftdi_setup(PROGRAMMER * pgm)
{
	avrftdi_t* pdata;

	
	if(!(pgm->cookie = calloc(sizeof(avrftdi_t), 1))) {
		log_err("Error allocating memory.\n");
		exit(1);
	}
	pdata = to_pdata(pgm);

	pdata->ftdic = ftdi_new();
	if(!pdata->ftdic)
	{
		log_err("Error allocating memory.\n");
		exit(1);
	}
	E_VOID(ftdi_init(pdata->ftdic), pdata->ftdic);

	pdata->pin_value = 0;
	pdata->pin_direction = 0;
	pdata->led_mask = 0;
	pdata->lext_byte = 0xff;
}

static void
avrftdi_teardown(PROGRAMMER * pgm)
{
	avrftdi_t* pdata = to_pdata(pgm);

	if(pdata) {
		ftdi_deinit(pdata->ftdic);
		ftdi_free(pdata->ftdic);
		free(pdata);
	}
}

void avrftdi_initpgm(PROGRAMMER *pgm) {
	strcpy(pgm->type, "avrftdi");

	/*
	 * mandatory functions
	 */

	pgm->initialize = avrftdi_initialize;
	pgm->display = avrftdi_display;
	pgm->enable = avrftdi_enable;
	pgm->disable = avrftdi_disable;
	pgm->powerup = avrftdi_powerup;
	pgm->powerdown = avrftdi_powerdown;
	pgm->program_enable = avrftdi_program_enable;
	pgm->chip_erase = avrftdi_chip_erase;
	pgm->cmd = avrftdi_cmd;
	pgm->open = avrftdi_open;
	pgm->close = avrftdi_close;
	pgm->read_byte = avr_read_byte_default;
	pgm->write_byte = avr_write_byte_default;

	/*
	 * optional functions
	 */

	pgm->paged_write = avrftdi_paged_write;
	pgm->paged_load = avrftdi_paged_load;

	pgm->setpin = set_pin;

	pgm->setup = avrftdi_setup;
	pgm->teardown = avrftdi_teardown;

	pgm->rdy_led = set_led_rdy;
	pgm->err_led = set_led_err;
	pgm->pgm_led = set_led_pgm;
	pgm->vfy_led = set_led_vfy;
}

#endif /* DO_NOT_BUILD_AVRFTDI */


const char avrftdi_desc[] = "Interface to the MPSSE Engine of FTDI Chips using libftdi.";