avrdude/buspirate.c

/*
 * avrdude - A Downloader/Uploader for AVR device programmers
 *
 * avrdude support for The Bus Pirate - universal serial interface
 *
 * Copyright (C) 2009 Michal Ludvig <mludvig@logix.net.nz>
 *
 * 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/*
 * BusPirate       AVR Chip
 * ---------       --------
 *       GND  <->  GND
 *       +5V  <->  Vcc
 *        CS  <->  RESET
 *      MOSI  <->  MOSI
 *      MISO  <->  MISO
 *   SCL/CLK  <->  SCK
 *
 * Tested with BusPirate PTH, firmware version 2.1 programming ATmega328P
 */

/* $Id$ */

#include "ac_cfg.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "avrdude.h"
#include "avr.h"
#include "pgm.h"
#include "serial.h"

/* ====== Private data structure ====== */
/* CS and AUX pin bitmasks in 
 * 0100wxyz – Configure peripherals command */
#define BP_RESET_CS     0x01
#define BP_RESET_AUX    0x02
#define BP_RESET_AUX2   0x04

#define BP_FLAG_IN_BINMODE          (1<<0)
#define BP_FLAG_XPARM_FORCE_ASCII   (1<<1)
#define BP_FLAG_XPARM_RESET         (1<<2)
#define BP_FLAG_XPARM_SPIFREQ       (1<<3)

struct pdata
{
	char	hw_version[10];
	int		fw_version;		/* = 100*fw_major + fw_minor */
	int		binmode_version;
	int		bin_spi_version;
	int		current_peripherals_config;
	int		spifreq;		/* 0..7 - see buspirate manual for what freq each value means */
	int		reset;			/* See BP_RESET_* above */
};
#define PDATA(pgm) ((struct pdata *)(pgm->cookie))

/* Binary mode is available from firmware v2.7 on */
#define FW_BINMODE_VER	207

/* ====== Feature checks ====== */
static inline int
buspirate_has_aux2(struct programmer_t *pgm)
{
	return ((PDATA(pgm)->fw_version >= 300) &&
			strcmp(PDATA(pgm)->hw_version, "v1a") == 0);
}

static inline int
buspirate_uses_ascii(struct programmer_t *pgm)
{
	return (pgm->flag & BP_FLAG_XPARM_FORCE_ASCII) ||
		(PDATA(pgm)->fw_version < FW_BINMODE_VER);
}

/* ====== Serial talker functions - binmode ====== */

static void dump_mem(char *buf, size_t len)
{
	size_t i;

	for (i = 0; i<len; i++) {
		if (i % 8 == 0)
			fprintf(stderr, "\t");
		fprintf(stderr, "0x%02x ", (unsigned)buf[i] & 0xFF);
		if (i % 8 == 3)
			fprintf(stderr, "  ");
		else if (i % 8 == 7)
			fprintf(stderr, "\n");
	}
	if (i % 8 != 7)
		fprintf(stderr, "\n");
}

static int buspirate_send_bin(struct programmer_t *pgm, char *data, size_t len)
{
	int rc;

	if (verbose > 1) {
		fprintf(stderr, "%s: buspirate_send_bin():\n", progname);
		dump_mem(data, len);
	}

	rc = serial_send(&pgm->fd, (unsigned char *)data, len);

	return rc;
}

static int buspirate_recv_bin(struct programmer_t *pgm, char *buf, size_t len)
{
	int rc;

	rc = serial_recv(&pgm->fd, (unsigned char *)buf, len);
	if (rc < 0)
		return EOF;
	if (verbose > 1) {
		fprintf(stderr, "%s: buspirate_recv_bin():\n", progname);
		dump_mem(buf, len);
	}

	return len;
}

static int buspirate_expect_bin(struct programmer_t *pgm,
								char *send_data, size_t send_len,
								char *expect_data, size_t expect_len)
{
	char *recv_buf = alloca(expect_len);
	if (!pgm->flag & BP_FLAG_IN_BINMODE) {
		fprintf(stderr, "BusPirate: Internal error: buspirate_send_bin() called from ascii mode");
		exit(1);
	}

	buspirate_send_bin(pgm, send_data, send_len);
	buspirate_recv_bin(pgm, recv_buf, expect_len);
	if (memcmp(expect_data, recv_buf, expect_len) != 0)
		return 0;
	return 1;
}

static int buspirate_expect_bin_byte(struct programmer_t *pgm,
									 char send_byte, char expect_byte)
{
	return buspirate_expect_bin(pgm, &send_byte, 1, &expect_byte, 1);
}

/* ====== Serial talker functions - ascii mode ====== */

static int buspirate_getc(struct programmer_t *pgm)
{
	int rc;
	unsigned char ch = 0;

	if (pgm->flag & BP_FLAG_IN_BINMODE) {
		fprintf(stderr, "BusPirate: Internal error: buspirate_getc() called from binmode");
		exit(1);
	}

	rc = serial_recv(&pgm->fd, &ch, 1);
	if (rc < 0)
		return EOF;
	return ch;
}

static char *buspirate_readline(struct programmer_t *pgm, char *buf, size_t len)
{
	char *buf_p;
	long orig_serial_recv_timeout = serial_recv_timeout;

	/* Static local buffer - this may come handy at times */
	static char buf_local[100];

	if (buf == NULL) {
		buf = buf_local;
		len = sizeof(buf_local);
	}
	buf_p = buf;
	memset(buf, 0, len);
	while (buf_p < (buf + len - 1)) { /* keep the very last byte == 0 */
		*buf_p = buspirate_getc(pgm);
		if (*buf_p == '\r')
			continue;
		if (*buf_p == '\n')
			break;
		if (*buf_p == EOF) {
			*buf_p = '\0';
			break;
		}
		buf_p++;
		serial_recv_timeout = 100;
	}
	serial_recv_timeout = orig_serial_recv_timeout;
	if (verbose)
		fprintf(stderr, "%s: buspirate_readline(): %s%s",
				progname, buf,
				buf[strlen(buf) - 1] == '\n' ? "" : "\n");
	if (! buf[0]) {
		fprintf(stderr,
				"%s: buspirate_readline(): programmer is not responding\n",
				progname);
		exit(1);
	}
	return buf;
}

static int buspirate_send(struct programmer_t *pgm, char *str)
{
	int rc;

	if (verbose)
		fprintf(stderr, "%s: buspirate_send(): %s", progname, str);

	if (pgm->flag & BP_FLAG_IN_BINMODE) {
		fprintf(stderr, "BusPirate: Internal error: buspirate_send() called from binmode");
		exit(1);
	}

	rc = serial_send(&pgm->fd, (unsigned char *)str, strlen(str));
	if (rc)
		return rc;
	while (strcmp(buspirate_readline(pgm, NULL, 0), str) != 0)
		/* keep reading until we get what we sent there */
		;
	/* by now we should be in sync */
	return 0;
}

static int buspirate_is_prompt(char *str)
{
	/* Prompt ends with '>' all other input probably ends with '\n' */
	return (str[strlen(str) - 1] == '>');
}

static int buspirate_expect(struct programmer_t *pgm, char *send,
							char *expect, int wait_for_prompt)
{
	int got_it = 0;
	size_t expect_len = strlen(expect);
	char *rcvd;

	buspirate_send(pgm, send);
	while (1) {
		rcvd = buspirate_readline(pgm, NULL, 0);

		if (strncmp(rcvd, expect, expect_len) == 0)
			got_it = 1;

		if (buspirate_is_prompt(rcvd))
			break;
	}
	return got_it;
}

/* ====== Do-nothing functions ====== */
static void buspirate_dummy_6(struct programmer_t *pgm,
				const char *p)
{
}

/* ====== Config / parameters handling functions ====== */
static int
buspirate_parseextparms(struct programmer_t *pgm, LISTID extparms)
{
	LNODEID ln;
	const char *extended_param;
	char reset[10];
	char *preset = reset;	/* for strtok() */
	int spifreq;

	for (ln = lfirst(extparms); ln; ln = lnext(ln)) {
    	extended_param = ldata(ln);
		if (strcmp(extended_param, "ascii") == 0) {
			pgm->flag |= BP_FLAG_XPARM_FORCE_ASCII;
			continue;
		}
		if (sscanf(extended_param, "spifreq=%d", &spifreq) == 1) {
			if (spifreq & (~0x07)) {
				fprintf(stderr, "BusPirate: spifreq must be between 0 and 7.\n");
				fprintf(stderr, "BusPirate: see BusPirate manual for details.\n");
				return -1;
			}
			PDATA(pgm)->spifreq = spifreq;
			pgm->flag |= BP_FLAG_XPARM_SPIFREQ;
			continue;
		}

		if (sscanf(extended_param, "reset=%s", reset) == 1) {
			char *resetpin;
			while ((resetpin = strtok(preset, ","))) {
				preset = NULL;	/* for subsequent strtok() calls */
				if (strcasecmp(resetpin, "cs") == 0)
					PDATA(pgm)->reset |= BP_RESET_CS;
				else if (strcasecmp(resetpin, "aux") == 0 || strcasecmp(reset, "aux1") == 0)
					PDATA(pgm)->reset |= BP_RESET_AUX;
				else if (strcasecmp(resetpin, "aux2") == 0)
					PDATA(pgm)->reset |= BP_RESET_AUX2;
				else {
					fprintf(stderr, "BusPirate: reset must be either CS or AUX.\n");
					return -1;
				}
			}
			pgm->flag |= BP_FLAG_XPARM_RESET;
			continue;
		}
	}

	return 0;
}

static int
buspirate_verifyconfig(struct programmer_t *pgm)
{
	/* Default reset pin is CS */
	if (PDATA(pgm)->reset == 0x00)
		PDATA(pgm)->reset |= BP_RESET_CS;

	/* reset=AUX2 is only available on HW=v1a and FW>=3.0 */
	if ((PDATA(pgm)->reset & BP_RESET_AUX2) && !buspirate_has_aux2(pgm)) {
		fprintf(stderr, "BusPirate: Pin AUX2 is only available in binary mode\n");
		fprintf(stderr, "BusPirate: with hardware==v1a && firmware>=3.0\n");
		fprintf(stderr, "BusPirate: Your hardware==%s and firmware==%d.%d\n", 
				PDATA(pgm)->hw_version, PDATA(pgm)->fw_version/100, PDATA(pgm)->fw_version%100);
		return -1;
	}

	if ((PDATA(pgm)->reset != BP_RESET_CS) && buspirate_uses_ascii(pgm)) {
		fprintf(stderr, "BusPirate: RESET pin other than CS is not supported in ASCII mode\n");
		return -1;
	}

	if ((pgm->flag & BP_FLAG_XPARM_SPIFREQ) && buspirate_uses_ascii(pgm)) {
		fprintf(stderr, "BusPirate: SPI speed selection is not supported in ASCII mode\n");
		return -1;
	}

	return 0;
}

/* ====== Programmer methods ======= */
static int buspirate_open(struct programmer_t *pgm, char * port)
{
	/* BusPirate runs at 115200 by default */
	if(pgm->baudrate == 0)
		pgm->baudrate = 115200;

	strcpy(pgm->port, port);
	serial_open(port, pgm->baudrate, &pgm->fd);

	/* drain any extraneous input */
	serial_drain(&pgm->fd, 0);

	return 0;
}

static void buspirate_close(struct programmer_t *pgm)
{
	serial_close(&pgm->fd);
	pgm->fd.ifd = -1;
}

static void buspirate_reset_from_binmode(struct programmer_t *pgm)
{
	char buf[10];
	
	buf[0] = 0x00;	/* BinMode: revert to HiZ */
	buspirate_send_bin(pgm, buf, 1);

	buf[0] = 0x0F;	/* BinMode: reset */
	buspirate_send_bin(pgm, buf, 1);

	pgm->flag &= ~BP_FLAG_IN_BINMODE;
	while(1) {
		buspirate_readline(pgm, buf, sizeof(buf) - 1);
		if (buspirate_is_prompt(buf))
			break;
	}
	if (verbose)
		printf("BusPirate is back in the text mode\n");
}

static int buspirate_start_spi_mode_bin(struct programmer_t *pgm)
{
	char buf[20] = { '\0' };

	/* == Switch to binmode - send 20x '\0' == */
	buspirate_send_bin(pgm, buf, sizeof(buf));

	/* Expecting 'BBIOx' reply */
	memset(buf, 0, sizeof(buf));
	buspirate_recv_bin(pgm, buf, 5);
	if (sscanf(buf, "BBIO%d", &PDATA(pgm)->binmode_version) != 1) {
		fprintf(stderr, "Binary mode not confirmed: '%s'\n", buf);
		buspirate_reset_from_binmode(pgm);
		return -1;
	}
	if (verbose)
		printf("BusPirate binmode version: %d\n", PDATA(pgm)->binmode_version);

	pgm->flag |= BP_FLAG_IN_BINMODE;

	/* == Enter SPI mode == */
	buf[0] = 0x01;	/* Enter raw SPI mode */
	buspirate_send_bin(pgm, buf, 1);
	memset(buf, 0, sizeof(buf));
	buspirate_recv_bin(pgm, buf, 4);
	if (sscanf(buf, "SPI%d", &PDATA(pgm)->bin_spi_version) != 1) {
		fprintf(stderr, "SPI mode not confirmed: '%s'\n", buf);
		buspirate_reset_from_binmode(pgm);
		return -1;
	}
	if (verbose)
		printf("BusPirate SPI version: %d\n", PDATA(pgm)->bin_spi_version);

	/* 0b0100wxyz – Configure peripherals w=power, x=pull-ups/aux2, y=AUX, z=CS
	 * we want power (0x48) and all reset pins high. */
	PDATA(pgm)->current_peripherals_config  = 0x48;
	PDATA(pgm)->current_peripherals_config |= BP_RESET_CS;
	PDATA(pgm)->current_peripherals_config |= BP_RESET_AUX;
	if (buspirate_has_aux2(pgm))
		PDATA(pgm)->current_peripherals_config |= BP_RESET_AUX2;
	buspirate_expect_bin_byte(pgm, PDATA(pgm)->current_peripherals_config, 0x01);
	usleep(50000);	// sleep for 50ms after power up

	/* 01100xxx -  SPI speed
	 * xxx = 000=30kHz, 001=125kHz, 010=250kHz, 011=1MHz,
	 *       100=2MHz, 101=2.6MHz, 110=4MHz, 111=8MHz
	 * use 30kHz = 0x60 */
	buspirate_expect_bin_byte(pgm, 0x60 | PDATA(pgm)->spifreq, 0x01);

	/* 1000wxyz – SPI config, w=HiZ(0)/3.3v(1), x=CLK idle, y=CLK edge, z=SMP sample
	 * we want: 3.3V(1), idle low(0), data change on trailing edge (1), 
	 *          sample in the middle of the pulse (0)
	 *       => 0b10001010 = 0x8a */
	buspirate_expect_bin_byte(pgm, 0x8A, 0x01);

	return 0;
}

static int buspirate_start_spi_mode_ascii(struct programmer_t *pgm)
{
	int spi_cmd = -1;
	int cmd;
	char *rcvd, mode[11], buf[5];

	buspirate_send(pgm, "M\n");
	while(1) {
		rcvd = buspirate_readline(pgm, NULL, 0);
		if (spi_cmd == -1 && sscanf(rcvd, "%d. %10s", &cmd, mode)) {
			if (strcmp(mode, "SPI") == 0)
				spi_cmd = cmd;
		}
		if (buspirate_is_prompt(rcvd))
			break;
	}
	if (spi_cmd == -1) {
		fprintf(stderr,
				"%s: SPI mode number not found. Does your BusPirate support SPI?\n",
				progname);
		fprintf(stderr, "%s: Try powercycling your BusPirate and try again.\n",
				progname);
		return -1;
	}
	snprintf(buf, sizeof(buf), "%d\n", spi_cmd);
	buspirate_send(pgm, buf);
	buf[0] = '\0';
	while (1) {
		rcvd = buspirate_readline(pgm, NULL, 0);
		if (strstr(rcvd, "Normal (H=3.3V, L=GND)")) {
			/* BP firmware 2.1 defaults to Open-drain output.
			 * That doesn't work on my board, even with pull-up
			 * resistors. Select 3.3V output mode instead. */
			sscanf(rcvd, " %d.", &cmd);
			snprintf(buf, sizeof(buf), "%d\n", cmd);
		}
		if (buspirate_is_prompt(rcvd)) {
			if (strncmp(rcvd, "SPI>", 4) == 0) {
				printf("BusPirate is now configured for SPI\n");
				break;
			}
			/* Not yet 'SPI>' prompt */
			if (buf[0]) {
				buspirate_send(pgm, buf);
				buf[0] = '\0';
			} else
				buspirate_send(pgm, "\n");
		}
	}
	return 0;
}

static void buspirate_enable(struct programmer_t *pgm)
{
	char *rcvd;
	int fw_v1, fw_v2;

	printf("Detecting BusPirate...\n");
	buspirate_send(pgm, "#\n");
	while(1) {
		rcvd = buspirate_readline(pgm, NULL, 0);
		if (strncmp(rcvd, "RESET", 5) == 0)
			continue;
		if (buspirate_is_prompt(rcvd)) {
			puts("**");
			break;
		}
		sscanf(rcvd, "Bus Pirate %9s", PDATA(pgm)->hw_version);
		sscanf(rcvd, "Firmware v%d.%d", &fw_v1, &fw_v2);
		printf("**  %s", rcvd);
	}

	PDATA(pgm)->fw_version = 100 * fw_v1 + fw_v2;
	if (PDATA(pgm)->hw_version[0] == 0 || PDATA(pgm)->fw_version == 0) {
		fprintf(stderr, "BusPirate not detected. Aborting.\n");
		exit(1);
	}

	if (buspirate_verifyconfig(pgm) < 0)
		exit(1);

	if (PDATA(pgm)->fw_version >= FW_BINMODE_VER && !(pgm->flag & BP_FLAG_XPARM_FORCE_ASCII)) {
		printf("BusPirate: using BINARY mode\n");
		if (buspirate_start_spi_mode_bin(pgm) < 0)
			fprintf(stderr, "%s: Failed to start binary SPI mode\n", progname);
	}
	if (!pgm->flag & BP_FLAG_IN_BINMODE) {
		printf("BusPirate: using ASCII mode\n");
		if (buspirate_start_spi_mode_ascii(pgm) < 0) {
			fprintf(stderr, "%s: Failed to start ascii SPI mode\n", progname);
			exit(1);
		}
	}
}

static void buspirate_disable(struct programmer_t *pgm)
{
	if (pgm->flag & BP_FLAG_IN_BINMODE)
		buspirate_reset_from_binmode(pgm);
	else
		buspirate_expect(pgm, "#\n", "RESET", 1);
}

static int buspirate_initialize(struct programmer_t *pgm, AVRPART * p)
{
	pgm->powerup(pgm);

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

static void buspirate_powerup(struct programmer_t *pgm)
{
	if (pgm->flag & BP_FLAG_IN_BINMODE) {
		/* Powerup in BinMode is handled in SPI init */
		return;
	} else 
		if (buspirate_expect(pgm, "W\n", "POWER SUPPLIES ON", 1))
			return;

	fprintf(stderr, "%s: warning: did not get a response to PowerUp command.\n", progname);
	fprintf(stderr, "%s: warning: Trying to continue anyway...\n", progname);
}

static void buspirate_powerdown(struct programmer_t *pgm)
{
	if (pgm->flag & BP_FLAG_IN_BINMODE) {
		/* 0b0100wxyz – Configure peripherals w=power, x=pull-ups, y=AUX, z=CS
		 * we want everything off -- 0b01000000 = 0x40 */
		if (buspirate_expect_bin_byte(pgm, 0x40, 0x01))
			return;
	} else 
		if (buspirate_expect(pgm, "w\n", "POWER SUPPLIES OFF", 1))
			return;

	fprintf(stderr, "%s: warning: did not get a response to PowerDown command.\n", progname);
}

static int buspirate_cmd_bin(struct programmer_t *pgm,
							 unsigned char cmd[4],
							 unsigned char res[4])
{
	/* 0001xxxx – Bulk SPI transfer, send/read 1-16 bytes (0=1byte!)
	 * we are sending 4 bytes -> 0x13 */
	if (!buspirate_expect_bin_byte(pgm, 0x13, 0x01))
		return -1;

	buspirate_send_bin(pgm, (char *)cmd, 4);
	buspirate_recv_bin(pgm, (char *)res, 4);

	return 0;
}

static int buspirate_cmd_ascii(struct programmer_t *pgm,
							   unsigned char cmd[4],
							   unsigned char res[4])
{
	char buf[25];
	char *rcvd;
	int spi_write, spi_read, i = 0;

	snprintf(buf, sizeof(buf), "0x%02x 0x%02x 0x%02x 0x%02x\n",
			 cmd[0], cmd[1], cmd[2], cmd[3]);
	buspirate_send(pgm, buf);
	while (i < 4) {
		rcvd = buspirate_readline(pgm, NULL, 0);
		/* WRITE: 0xAC READ: 0x04 */
		if (sscanf(rcvd, "WRITE: 0x%x READ: 0x%x", &spi_write, &spi_read) == 2) {
			res[i++] = spi_read;
		}
		if (buspirate_is_prompt(rcvd))
			break;
	}

	if (i != 4) {
		fprintf(stderr, "%s: error: SPI has not read 4 bytes back\n", progname);
		return -1;
	}

	/* wait for prompt */
	while (buspirate_getc(pgm) != '>')
		/* do nothing */;

	return 0;
}

static int buspirate_cmd(struct programmer_t *pgm,
						 unsigned char cmd[4],
						 unsigned char res[4])
{
	if (pgm->flag & BP_FLAG_IN_BINMODE)
		return buspirate_cmd_bin(pgm, cmd, res);
	else
		return buspirate_cmd_ascii(pgm, cmd, res);
}

static int buspirate_program_enable(struct programmer_t *pgm, AVRPART * p)
{
	unsigned char cmd[4];
	unsigned char res[4];

	if (pgm->flag & BP_FLAG_IN_BINMODE) {
		/* Clear configured reset pin(s): CS and/or AUX and/or AUX2 */
		PDATA(pgm)->current_peripherals_config &= ~PDATA(pgm)->reset;
		buspirate_expect_bin_byte(pgm, PDATA(pgm)->current_peripherals_config, 0x01);
	}
	else
		buspirate_expect(pgm, "{\n", "CS ENABLED", 1);

	if (p->op[AVR_OP_PGM_ENABLE] == NULL) {
		fprintf(stderr,
				"program enable instruction not defined for part \"%s\"\n",
				p->desc);
		return -1;
	}

	memset(cmd, 0, sizeof(cmd));
	avr_set_bits(p->op[AVR_OP_PGM_ENABLE], cmd);
	pgm->cmd(pgm, cmd, res);

	if (res[2] != cmd[1])
		return -2;

	return 0;
}

static int buspirate_chip_erase(struct programmer_t *pgm, AVRPART * p)
{
	unsigned char cmd[4];
	unsigned char res[4];

	if (p->op[AVR_OP_CHIP_ERASE] == NULL) {
		fprintf(stderr,
				"chip erase instruction not defined for part \"%s\"\n",
				p->desc);
		return -1;
	}

	pgm->pgm_led(pgm, ON);

	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);

	pgm->pgm_led(pgm, OFF);

	return 0;
}

void buspirate_initpgm(struct programmer_t *pgm)
{
	strcpy(pgm->type, "BusPirate");

	pgm->display        = buspirate_dummy_6;

	/* BusPirate itself related methods */
	pgm->open           = buspirate_open;
	pgm->close          = buspirate_close;
	pgm->enable         = buspirate_enable;
	pgm->disable        = buspirate_disable;
	pgm->initialize     = buspirate_initialize;

	/* Chip related methods */
	pgm->powerup        = buspirate_powerup;
	pgm->powerdown      = buspirate_powerdown;
	pgm->program_enable = buspirate_program_enable;
	pgm->chip_erase     = buspirate_chip_erase;
	pgm->cmd            = buspirate_cmd;
	pgm->read_byte      = avr_read_byte_default;
	pgm->write_byte     = avr_write_byte_default;

	/* Support functions */
	pgm->parseextparams = buspirate_parseextparms;

	/* Allocate private data */
	if ((pgm->cookie = calloc(1, sizeof(struct pdata))) == 0) {
		fprintf(stderr, "%s: buspirate_initpgm(): Out of memory allocating private data\n",
				progname);
		exit(1);
	}
}