jtag: drivers: add support for FT232R sync bitbang JTAG interfaces

Change-Id: Ib88a9e270f5c2a50902a137bcc97fdefd5aad1c6
Signed-off-by: Matej Kogovsek <matej@hamradio.si>
Reviewed-on: http://openocd.zylin.com/4215
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>

6 files changed, 711 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index 562ec5a..f4f66ab 100644
--- a/configure.ac
+++ b/configure.ac
@@ -114,6 +114,7 @@ m4_define([USB1_ADAPTERS],
 	[[ti_icdi], [TI ICDI JTAG Programmer], [HLADAPTER_ICDI]],
 	[[ulink], [Keil ULINK JTAG Programmer], [ULINK]],
 	[[usb_blaster_2], [Altera USB-Blaster II Compatible], [USB_BLASTER_2]],
+	[[ft232r], [Bitbang mode of FT232R based devices], [FT232R]],
 	[[vsllink], [Versaloon-Link JTAG Programmer], [VSLLINK]]])
 
 m4_define([USB_ADAPTERS],
diff --git a/doc/openocd.texi b/doc/openocd.texi
index 3a38a96..ce9cd3b 100644
--- a/doc/openocd.texi
+++ b/doc/openocd.texi
@@ -2559,6 +2559,36 @@ For example adapter definitions, see the configuration files shipped in the
 
 @end deffn
 
+@deffn {Interface Driver} {ft232r}
+This driver is implementing synchronous bitbang mode of an FTDI FT232R
+USB UART bridge IC.
+
+List of connections (pin numbers for SSOP):
+@itemize @minus
+@item RXD(5) - TDI
+@item TXD(1) - TCK
+@item RTS(3) - TDO
+@item CTS(11) - TMS
+@item DTR(2) - TRST
+@item DCD(10) - SRST
+@end itemize
+
+These interfaces have several commands, used to configure the driver
+before initializing the JTAG scan chain:
+
+@deffn {Config Command} {ft232r_vid_pid} @var{vid} @var{pid}
+The vendor ID and product ID of the adapter. If not specified, default
+0x0403:0x6001 is used.
+@end deffn
+
+@deffn {Config Command} {ft232r_serial_desc} @var{serial}
+Specifies the @var{serial} of the adapter to use, in case the
+vendor provides unique IDs and more than one adapter is connected to
+the host. If not specified, serial numbers are not considered.
+@end deffn
+
+@end deffn
+
 @deffn {Interface Driver} {remote_bitbang}
 Drive JTAG from a remote process. This sets up a UNIX or TCP socket connection
 with a remote process and sends ASCII encoded bitbang requests to that process
diff --git a/src/jtag/drivers/Makefile.am b/src/jtag/drivers/Makefile.am
index 3e5974d..b3b4d21 100644
--- a/src/jtag/drivers/Makefile.am
+++ b/src/jtag/drivers/Makefile.am
@@ -80,6 +80,9 @@ if USB_BLASTER_DRIVER
 %C%_libocdjtagdrivers_la_LIBADD += %D%/usb_blaster/libocdusbblaster.la
 include %D%/usb_blaster/Makefile.am
 endif
+if FT232R
+DRIVERFILES += %D%/ft232r.c
+endif
 if AMTJTAGACCEL
 DRIVERFILES += %D%/amt_jtagaccel.c
 endif
diff --git a/src/jtag/drivers/ft232r.c b/src/jtag/drivers/ft232r.c
new file mode 100644
index 0000000..fc3d75f
--- /dev/null
+++ b/src/jtag/drivers/ft232r.c
@@ -0,0 +1,669 @@
+/***************************************************************************
+ *   Copyright (C) 2010 Serge Vakulenko                                    *
+ *   serge@vak.ru                                                          *
+ *                                                                         *
+ *   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/>. *
+ ***************************************************************************/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#if IS_CYGWIN == 1
+#include "windows.h"
+#undef LOG_ERROR
+#endif
+
+/* project specific includes */
+#include <jtag/interface.h>
+#include <jtag/commands.h>
+#include <helper/time_support.h>
+#include "libusb1_common.h"
+
+/* system includes */
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <time.h>
+
+/*
+ *   Bit 7 (0x80, pin 6, RI ): unused.
+ *   Bit 6 (0x40, pin 10,DCD): /SYSRST output.
+ *   Bit 5 (0x20, pin 9, DSR): unused.
+ *   Bit 4 (0x10, pin 2, DTR): /TRST output.
+ *   Bit 3 (0x08, pin 11,CTS): TMS output.
+ *   Bit 2 (0x04, pin 3, RTS): TDO input.
+ *   Bit 1 (0x02, pin 5, RXD): TDI output.
+ *   Bit 0 (0x01, pin 1, TXD): TCK output.
+ *
+ * Sync bit bang mode is implemented as described in FTDI Application
+ * Note AN232R-01: "Bit Bang Modes for the FT232R and FT245R".
+ */
+#define TCK			(1 << 0)
+#define TDI			(1 << 1)
+#define READ_TDO		(1 << 2)
+#define TMS			(1 << 3)
+#define NTRST			(1 << 4)
+#define NSYSRST			(1 << 6)
+
+/*
+ * USB endpoints.
+ */
+#define IN_EP			0x02
+#define OUT_EP			0x81
+
+/* Requests */
+#define SIO_RESET		0 /* Reset the port */
+#define SIO_MODEM_CTRL		1 /* Set the modem control register */
+#define SIO_SET_FLOW_CTRL	2 /* Set flow control register */
+#define SIO_SET_BAUD_RATE	3 /* Set baud rate */
+#define SIO_SET_DATA		4 /* Set the data characteristics of the port */
+#define SIO_POLL_MODEM_STATUS	5
+#define SIO_SET_EVENT_CHAR	6
+#define SIO_SET_ERROR_CHAR	7
+#define SIO_SET_LATENCY_TIMER	9
+#define SIO_GET_LATENCY_TIMER	10
+#define SIO_SET_BITMODE		11
+#define SIO_READ_PINS		12
+#define SIO_READ_EEPROM		0x90
+#define SIO_WRITE_EEPROM	0x91
+#define SIO_ERASE_EEPROM	0x92
+
+#define FT232R_BUF_SIZE		4000
+
+static char *ft232r_serial_desc;
+static uint16_t ft232r_vid = 0x0403; /* FTDI */
+static uint16_t ft232r_pid = 0x6001; /* FT232R */
+static jtag_libusb_device_handle *adapter;
+
+static uint8_t *ft232r_output;
+static size_t ft232r_output_len;
+
+/**
+ * Perform sync bitbang output/input transaction.
+ * Before call, an array ft232r_output[] should be filled with data to send.
+ * Counter ft232r_output_len contains the number of bytes to send.
+ * On return, received data is put back to array ft232r_output[].
+ */
+static int ft232r_send_recv(void)
+{
+	/* FIFO TX buffer has 128 bytes.
+	 * FIFO RX buffer has 256 bytes.
+	 * First two bytes of received packet contain contain modem
+	 * and line status and are ignored.
+	 * Unfortunately, transfer sizes bigger than 64 bytes
+	 * frequently cause hang ups. */
+	assert(ft232r_output_len > 0);
+
+	size_t total_written = 0;
+	size_t total_read = 0;
+	int rxfifo_free = 128;
+
+	while (total_read < ft232r_output_len) {
+		/* Write */
+		int bytes_to_write = ft232r_output_len - total_written;
+		if (bytes_to_write > 64)
+			bytes_to_write = 64;
+		if (bytes_to_write > rxfifo_free)
+			bytes_to_write = rxfifo_free;
+
+		if (bytes_to_write) {
+			int n = jtag_libusb_bulk_write(adapter, IN_EP,
+				(char *) ft232r_output + total_written,
+				bytes_to_write, 1000);
+
+			if (n == 0) {
+				LOG_ERROR("usb bulk write failed");
+				return ERROR_JTAG_DEVICE_ERROR;
+			}
+
+			total_written += n;
+			rxfifo_free -= n;
+		}
+
+		/* Read */
+		uint8_t reply[64];
+
+		int n = jtag_libusb_bulk_read(adapter, OUT_EP,
+			(char *) reply,
+			sizeof(reply), 1000);
+
+		if (n == 0) {
+			LOG_ERROR("usb bulk read failed");
+			return ERROR_JTAG_DEVICE_ERROR;
+		}
+		if (n > 2) {
+			/* Copy data, ignoring first 2 bytes. */
+			memcpy(ft232r_output + total_read, reply + 2, n - 2);
+			int bytes_read = n - 2;
+			total_read += bytes_read;
+			rxfifo_free += bytes_read;
+			if (total_read > total_written) {
+				LOG_ERROR("read more bytes than wrote");
+				return ERROR_JTAG_DEVICE_ERROR;
+			}
+		}
+	}
+	ft232r_output_len = 0;
+	return ERROR_OK;
+}
+
+/**
+ * Add one TCK/TMS/TDI sample to send buffer.
+ */
+static void ft232r_write(int tck, int tms, int tdi)
+{
+	unsigned out_value = NTRST | NSYSRST;
+	if (tck)
+		out_value |= TCK;
+	if (tms)
+		out_value |= TMS;
+	if (tdi)
+		out_value |= TDI;
+
+	if (ft232r_output_len >= FT232R_BUF_SIZE) {
+		/* FIXME: should we just execute queue here? */
+		LOG_ERROR("ft232r_write: buffer overflow");
+		return;
+	}
+	ft232r_output[ft232r_output_len++] = out_value;
+}
+
+/**
+ * Control /TRST and /SYSRST pins.
+ * Perform immediate bitbang transaction.
+ */
+static void ft232r_reset(int trst, int srst)
+{
+	unsigned out_value = NTRST | NSYSRST;
+	LOG_DEBUG("ft232r_reset(%d,%d)", trst, srst);
+
+	if (trst == 1)
+		out_value &= ~NTRST;		/* switch /TRST low */
+	else if (trst == 0)
+		out_value |= NTRST;			/* switch /TRST high */
+
+	if (srst == 1)
+		out_value &= ~NSYSRST;		/* switch /SYSRST low */
+	else if (srst == 0)
+		out_value |= NSYSRST;		/* switch /SYSRST high */
+
+	if (ft232r_output_len >= FT232R_BUF_SIZE) {
+		/* FIXME: should we just execute queue here? */
+		LOG_ERROR("ft232r_write: buffer overflow");
+		return;
+	}
+
+	ft232r_output[ft232r_output_len++] = out_value;
+	ft232r_send_recv();
+}
+
+static int ft232r_speed(int divisor)
+{
+	int baud = (divisor == 0) ? 3000000 :
+		(divisor == 1) ? 2000000 :
+		3000000 / divisor;
+	LOG_DEBUG("ft232r_speed(%d) rate %d bits/sec", divisor, baud);
+
+	if (jtag_libusb_control_transfer(adapter,
+		LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_RECIPIENT_DEVICE | LIBUSB_ENDPOINT_OUT,
+		SIO_SET_BAUD_RATE, divisor, 0, 0, 0, 1000) != 0) {
+		LOG_ERROR("cannot set baud rate");
+		return ERROR_JTAG_DEVICE_ERROR;
+	}
+	return ERROR_OK;
+}
+
+static int ft232r_init(void)
+{
+	uint16_t avids[] = {ft232r_vid, 0};
+	uint16_t apids[] = {ft232r_pid, 0};
+	if (jtag_libusb_open(avids, apids, ft232r_serial_desc, &adapter)) {
+		LOG_ERROR("ft232r not found: vid=%04x, pid=%04x, serial=%s\n",
+			ft232r_vid, ft232r_pid, (ft232r_serial_desc == NULL) ? "[any]" : ft232r_serial_desc);
+		return ERROR_JTAG_INIT_FAILED;
+	}
+
+	libusb_detach_kernel_driver(adapter, 0);
+
+	if (jtag_libusb_claim_interface(adapter, 0)) {
+		LOG_ERROR("unable to claim interface");
+		return ERROR_JTAG_INIT_FAILED;
+	}
+
+	/* Reset the device. */
+	if (jtag_libusb_control_transfer(adapter,
+		LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_RECIPIENT_DEVICE | LIBUSB_ENDPOINT_OUT,
+		SIO_RESET, 0, 0, 0, 0, 1000) != 0) {
+		LOG_ERROR("unable to reset device");
+		return ERROR_JTAG_INIT_FAILED;
+	}
+
+	/* Sync bit bang mode. */
+	if (jtag_libusb_control_transfer(adapter,
+		LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_RECIPIENT_DEVICE | LIBUSB_ENDPOINT_OUT,
+		SIO_SET_BITMODE, TCK | TDI | TMS | NTRST | NSYSRST | 0x400,
+		0, 0, 0, 1000) != 0) {
+		LOG_ERROR("cannot set sync bitbang mode");
+		return ERROR_JTAG_INIT_FAILED;
+	}
+
+	/* Exactly 500 nsec between updates. */
+	unsigned divisor = 1;
+	unsigned char latency_timer = 1;
+
+	/* Frequency divisor is 14-bit non-zero value. */
+	if (jtag_libusb_control_transfer(adapter,
+		LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_RECIPIENT_DEVICE | LIBUSB_ENDPOINT_OUT,
+		SIO_SET_BAUD_RATE, divisor,
+		0, 0, 0, 1000) != 0) {
+		LOG_ERROR("cannot set baud rate");
+		return ERROR_JTAG_INIT_FAILED;
+	}
+	if (jtag_libusb_control_transfer(adapter,
+		LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_RECIPIENT_DEVICE | LIBUSB_ENDPOINT_OUT,
+		SIO_SET_LATENCY_TIMER, latency_timer, 0, 0, 0, 1000) != 0) {
+		LOG_ERROR("unable to set latency timer");
+		return ERROR_JTAG_INIT_FAILED;
+	}
+
+	ft232r_output = malloc(FT232R_BUF_SIZE);
+	if (ft232r_output == NULL) {
+		LOG_ERROR("Unable to allocate memory for the buffer");
+		return ERROR_JTAG_INIT_FAILED;
+	}
+
+	return ERROR_OK;
+}
+
+static int ft232r_quit(void)
+{
+	if (jtag_libusb_release_interface(adapter, 0) != 0)
+		LOG_ERROR("usb release interface failed");
+
+	jtag_libusb_close(adapter);
+	free(ft232r_output);
+
+	return ERROR_OK;
+}
+
+static int ft232r_speed_div(int divisor, int *khz)
+{
+	/* Maximum 3 Mbaud for bit bang mode. */
+	if (divisor == 0)
+		*khz = 3000;
+	else if (divisor == 1)
+		*khz = 2000;
+	else
+		*khz = 3000 / divisor;
+	return ERROR_OK;
+}
+
+static int ft232r_khz(int khz, int *divisor)
+{
+	if (khz == 0) {
+		LOG_DEBUG("RCLK not supported");
+		return ERROR_FAIL;
+	}
+
+	/* Calculate frequency divisor. */
+	if (khz > 2500)
+		*divisor = 0;		/* Special case: 3 MHz */
+	else if (khz > 1700)
+		*divisor = 1;		/* Special case: 2 MHz */
+	else {
+		*divisor = (2*3000 / khz + 1) / 2;
+		if (*divisor > 0x3FFF)
+			*divisor = 0x3FFF;
+	}
+	return ERROR_OK;
+}
+
+COMMAND_HANDLER(ft232r_handle_serial_desc_command)
+{
+	if (CMD_ARGC == 1)
+		ft232r_serial_desc = strdup(CMD_ARGV[0]);
+	else
+		LOG_ERROR("require exactly one argument to "
+				  "ft232r_serial_desc <serial>");
+	return ERROR_OK;
+}
+
+COMMAND_HANDLER(ft232r_handle_vid_pid_command)
+{
+	if (CMD_ARGC > 2) {
+		LOG_WARNING("ignoring extra IDs in ft232r_vid_pid "
+					"(maximum is 1 pair)");
+		CMD_ARGC = 2;
+	}
+	if (CMD_ARGC == 2) {
+		COMMAND_PARSE_NUMBER(u16, CMD_ARGV[0], ft232r_vid);
+		COMMAND_PARSE_NUMBER(u16, CMD_ARGV[1], ft232r_pid);
+	} else
+		LOG_WARNING("incomplete ft232r_vid_pid configuration");
+
+	return ERROR_OK;
+}
+
+static const struct command_registration ft232r_command_handlers[] = {
+	{
+		.name = "ft232r_serial_desc",
+		.handler = ft232r_handle_serial_desc_command,
+		.mode = COMMAND_CONFIG,
+		.help = "USB serial descriptor of the adapter",
+		.usage = "serial string",
+	},
+	{
+		.name = "ft232r_vid_pid",
+		.handler = ft232r_handle_vid_pid_command,
+		.mode = COMMAND_CONFIG,
+		.help = "USB VID and PID of the adapter",
+		.usage = "vid pid",
+	},
+	COMMAND_REGISTRATION_DONE
+};
+
+/*
+ * Synchronous bitbang protocol implementation.
+ */
+
+static void syncbb_end_state(tap_state_t state)
+{
+	if (tap_is_state_stable(state))
+		tap_set_end_state(state);
+	else {
+		LOG_ERROR("BUG: %i is not a valid end state", state);
+		exit(-1);
+	}
+}
+
+static void syncbb_state_move(int skip)
+{
+	int i = 0, tms = 0;
+	uint8_t tms_scan = tap_get_tms_path(tap_get_state(), tap_get_end_state());
+	int tms_count = tap_get_tms_path_len(tap_get_state(), tap_get_end_state());
+
+	for (i = skip; i < tms_count; i++) {
+		tms = (tms_scan >> i) & 1;
+		ft232r_write(0, tms, 0);
+		ft232r_write(1, tms, 0);
+	}
+	ft232r_write(0, tms, 0);
+
+	tap_set_state(tap_get_end_state());
+}
+
+/**
+ * Clock a bunch of TMS (or SWDIO) transitions, to change the JTAG
+ * (or SWD) state machine.
+ */
+static int syncbb_execute_tms(struct jtag_command *cmd)
+{
+	unsigned num_bits = cmd->cmd.tms->num_bits;
+	const uint8_t *bits = cmd->cmd.tms->bits;
+
+	DEBUG_JTAG_IO("TMS: %d bits", num_bits);
+
+	int tms = 0;
+	for (unsigned i = 0; i < num_bits; i++) {
+		tms = ((bits[i/8] >> (i % 8)) & 1);
+		ft232r_write(0, tms, 0);
+		ft232r_write(1, tms, 0);
+	}
+	ft232r_write(0, tms, 0);
+
+	return ERROR_OK;
+}
+
+static void syncbb_path_move(struct pathmove_command *cmd)
+{
+	int num_states = cmd->num_states;
+	int state_count;
+	int tms = 0;
+
+	state_count = 0;
+	while (num_states) {
+		if (tap_state_transition(tap_get_state(), false) == cmd->path[state_count]) {
+			tms = 0;
+		} else if (tap_state_transition(tap_get_state(), true) == cmd->path[state_count]) {
+			tms = 1;
+		} else {
+			LOG_ERROR("BUG: %s -> %s isn't a valid TAP transition",
+				tap_state_name(tap_get_state()),
+				tap_state_name(cmd->path[state_count]));
+			exit(-1);
+		}
+
+		ft232r_write(0, tms, 0);
+		ft232r_write(1, tms, 0);
+
+		tap_set_state(cmd->path[state_count]);
+		state_count++;
+		num_states--;
+	}
+
+	ft232r_write(0, tms, 0);
+
+	tap_set_end_state(tap_get_state());
+}
+
+static void syncbb_runtest(int num_cycles)
+{
+	int i;
+
+	tap_state_t saved_end_state = tap_get_end_state();
+
+	/* only do a state_move when we're not already in IDLE */
+	if (tap_get_state() != TAP_IDLE) {
+		syncbb_end_state(TAP_IDLE);
+		syncbb_state_move(0);
+	}
+
+	/* execute num_cycles */
+	for (i = 0; i < num_cycles; i++) {
+		ft232r_write(0, 0, 0);
+		ft232r_write(1, 0, 0);
+	}
+	ft232r_write(0, 0, 0);
+
+	/* finish in end_state */
+	syncbb_end_state(saved_end_state);
+	if (tap_get_state() != tap_get_end_state())
+		syncbb_state_move(0);
+}
+
+/**
+ * Function syncbb_stableclocks
+ * issues a number of clock cycles while staying in a stable state.
+ * Because the TMS value required to stay in the RESET state is a 1, whereas
+ * the TMS value required to stay in any of the other stable states is a 0,
+ * this function checks the current stable state to decide on the value of TMS
+ * to use.
+ */
+static void syncbb_stableclocks(int num_cycles)
+{
+	int tms = (tap_get_state() == TAP_RESET ? 1 : 0);
+	int i;
+
+	/* send num_cycles clocks onto the cable */
+	for (i = 0; i < num_cycles; i++) {
+		ft232r_write(1, tms, 0);
+		ft232r_write(0, tms, 0);
+	}
+}
+
+static void syncbb_scan(bool ir_scan, enum scan_type type, uint8_t *buffer, int scan_size)
+{
+	tap_state_t saved_end_state = tap_get_end_state();
+	int bit_cnt, bit0_index;
+
+	if (!((!ir_scan && (tap_get_state() == TAP_DRSHIFT)) || (ir_scan && (tap_get_state() == TAP_IRSHIFT)))) {
+		if (ir_scan)
+			syncbb_end_state(TAP_IRSHIFT);
+		else
+			syncbb_end_state(TAP_DRSHIFT);
+
+		syncbb_state_move(0);
+		syncbb_end_state(saved_end_state);
+	}
+
+	bit0_index = ft232r_output_len;
+	for (bit_cnt = 0; bit_cnt < scan_size; bit_cnt++) {
+		int tms = (bit_cnt == scan_size-1) ? 1 : 0;
+		int tdi;
+		int bytec = bit_cnt/8;
+		int bcval = 1 << (bit_cnt % 8);
+
+		/* if we're just reading the scan, but don't care about the output
+		 * default to outputting 'low', this also makes valgrind traces more readable,
+		 * as it removes the dependency on an uninitialised value
+		 */
+		tdi = 0;
+		if ((type != SCAN_IN) && (buffer[bytec] & bcval))
+			tdi = 1;
+
+		ft232r_write(0, tms, tdi);
+		ft232r_write(1, tms, tdi);
+	}
+
+	if (tap_get_state() != tap_get_end_state()) {
+		/* we *KNOW* the above loop transitioned out of
+		 * the shift state, so we skip the first state
+		 * and move directly to the end state.
+		 */
+		syncbb_state_move(1);
+	}
+	ft232r_send_recv();
+
+	if (type != SCAN_OUT)
+		for (bit_cnt = 0; bit_cnt < scan_size; bit_cnt++) {
+			int bytec = bit_cnt/8;
+			int bcval = 1 << (bit_cnt % 8);
+			int val = ft232r_output[bit0_index + bit_cnt*2 + 1];
+
+			if (val & READ_TDO)
+				buffer[bytec] |= bcval;
+			else
+				buffer[bytec] &= ~bcval;
+		}
+}
+
+static int syncbb_execute_queue(void)
+{
+	struct jtag_command *cmd = jtag_command_queue; /* currently processed command */
+	int scan_size;
+	enum scan_type type;
+	uint8_t *buffer;
+	int retval;
+
+	/* return ERROR_OK, unless a jtag_read_buffer returns a failed check
+	 * that wasn't handled by a caller-provided error handler
+	 */
+	retval = ERROR_OK;
+
+/*	ft232r_blink(1);*/
+
+	while (cmd) {
+		switch (cmd->type) {
+			case JTAG_RESET:
+				LOG_DEBUG_IO("reset trst: %i srst %i", cmd->cmd.reset->trst, cmd->cmd.reset->srst);
+
+				if ((cmd->cmd.reset->trst == 1) ||
+					(cmd->cmd.reset->srst &&
+					(jtag_get_reset_config() & RESET_SRST_PULLS_TRST))) {
+					tap_set_state(TAP_RESET);
+				}
+				ft232r_reset(cmd->cmd.reset->trst, cmd->cmd.reset->srst);
+				break;
+
+			case JTAG_RUNTEST:
+				LOG_DEBUG_IO("runtest %i cycles, end in %s", cmd->cmd.runtest->num_cycles,
+					tap_state_name(cmd->cmd.runtest->end_state));
+
+				syncbb_end_state(cmd->cmd.runtest->end_state);
+				syncbb_runtest(cmd->cmd.runtest->num_cycles);
+				break;
+
+			case JTAG_STABLECLOCKS:
+				/* this is only allowed while in a stable state.  A check for a stable
+				 * state was done in jtag_add_clocks()
+				 */
+				syncbb_stableclocks(cmd->cmd.stableclocks->num_cycles);
+				break;
+
+			case JTAG_TLR_RESET: /* renamed from JTAG_STATEMOVE */
+				LOG_DEBUG_IO("statemove end in %s", tap_state_name(cmd->cmd.statemove->end_state));
+
+				syncbb_end_state(cmd->cmd.statemove->end_state);
+				syncbb_state_move(0);
+				break;
+
+			case JTAG_PATHMOVE:
+				LOG_DEBUG_IO("pathmove: %i states, end in %s", cmd->cmd.pathmove->num_states,
+					tap_state_name(cmd->cmd.pathmove->path[cmd->cmd.pathmove->num_states - 1]));
+
+				syncbb_path_move(cmd->cmd.pathmove);
+				break;
+
+			case JTAG_SCAN:
+				LOG_DEBUG_IO("%s scan end in %s",  (cmd->cmd.scan->ir_scan) ? "IR" : "DR",
+					tap_state_name(cmd->cmd.scan->end_state));
+
+				syncbb_end_state(cmd->cmd.scan->end_state);
+				scan_size = jtag_build_buffer(cmd->cmd.scan, &buffer);
+				type = jtag_scan_type(cmd->cmd.scan);
+				syncbb_scan(cmd->cmd.scan->ir_scan, type, buffer, scan_size);
+				if (jtag_read_buffer(buffer, cmd->cmd.scan) != ERROR_OK)
+					retval = ERROR_JTAG_QUEUE_FAILED;
+				if (buffer)
+					free(buffer);
+				break;
+
+			case JTAG_SLEEP:
+				LOG_DEBUG_IO("sleep %" PRIi32, cmd->cmd.sleep->us);
+
+				jtag_sleep(cmd->cmd.sleep->us);
+				break;
+
+			case JTAG_TMS:
+				retval = syncbb_execute_tms(cmd);
+				break;
+			default:
+				LOG_ERROR("BUG: unknown JTAG command type encountered");
+				exit(-1);
+		}
+		if (ft232r_output_len > 0)
+			ft232r_send_recv();
+		cmd = cmd->next;
+	}
+/*	ft232r_blink(0);*/
+
+	return retval;
+}
+
+struct jtag_interface ft232r_interface = {
+	.name = "ft232r",
+	.commands = ft232r_command_handlers,
+	.transports = jtag_only,
+	.supported = DEBUG_CAP_TMS_SEQ,
+
+	.execute_queue = syncbb_execute_queue,
+
+	.speed = ft232r_speed,
+	.init = ft232r_init,
+	.quit = ft232r_quit,
+	.speed_div = ft232r_speed_div,
+	.khz = ft232r_khz,
+};
diff --git a/src/jtag/interfaces.c b/src/jtag/interfaces.c
index 174c63a..ddeadb4 100644
--- a/src/jtag/interfaces.c
+++ b/src/jtag/interfaces.c
@@ -60,6 +60,9 @@ extern struct jtag_interface usb_blaster_interface;
 #if BUILD_JTAG_VPI == 1
 extern struct jtag_interface jtag_vpi_interface;
 #endif
+#if BUILD_FT232R == 1
+extern struct jtag_interface ft232r_interface;
+#endif
 #if BUILD_AMTJTAGACCEL == 1
 extern struct jtag_interface amt_jtagaccel_interface;
 #endif
@@ -159,6 +162,9 @@ struct jtag_interface *jtag_interfaces[] = {
 #if BUILD_JTAG_VPI == 1
 		&jtag_vpi_interface,
 #endif
+#if BUILD_FT232R == 1
+		&ft232r_interface,
+#endif
 #if BUILD_AMTJTAGACCEL == 1
 		&amt_jtagaccel_interface,
 #endif
diff --git a/tcl/interface/ft232r.cfg b/tcl/interface/ft232r.cfg
new file mode 100644
index 0000000..b4f71c8
--- /dev/null
+++ b/tcl/interface/ft232r.cfg
@@ -0,0 +1,2 @@
+interface ft232r
+adapter_khz 1000