ft232r.c

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// SPDX-License-Identifier: GPL-2.0-or-later
 
/***************************************************************************
 *   Copyright (C) 2010 Serge Vakulenko                                    *
 *   serge@vak.ru                                                          *
 ***************************************************************************/
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
 
#if IS_CYGWIN == 1
#include "windows.h"
#undef LOG_ERROR
#endif
 
/* project specific includes */
#include <jtag/adapter.h>
#include <jtag/interface.h>
#include <jtag/commands.h>
#include <helper/time_support.h>
#include "libusb_helper.h"
 
/* system includes */
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/time.h>
#include <time.h>
 
/*
 * Sync bit bang mode is implemented as described in FTDI Application
 * Note AN232R-01: "Bit Bang Modes for the FT232R and FT245R".
 */
 
/*
 * 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_EXTRA   4096
 
static uint16_t ft232r_vid = 0x0403; /* FTDI */
static uint16_t ft232r_pid = 0x6001; /* FT232R */
static struct libusb_device_handle *adapter;
 
static uint8_t *ft232r_output;
static size_t ft232r_output_len;
 
#define FT232R_BIT_COUNT 8
static char *ft232r_bit_name_array[FT232R_BIT_COUNT] = {
    "TXD", /* 0: pin 1  TCK output */
    "RXD", /* 1: pin 5  TDI output */
    "RTS", /* 2: pin 3  TDO input */
    "CTS", /* 3: pin 11 TMS output */
    "DTR", /* 4: pin 2  /TRST output */
    "DSR", /* 5: pin 9  unused */
    "DCD", /* 6: pin 10 /SYSRST output */
    "RI"   /* 7: pin 6  unused */
};
 
static int tck_gpio; /* initialized to 0 by default */
static int tdi_gpio = 1;
static int tdo_gpio = 2;
static int tms_gpio = 3;
static int ntrst_gpio = 4;
static int nsysrst_gpio = 6;
static size_t ft232r_buf_size = FT232R_BUF_SIZE_EXTRA;
static uint16_t ft232r_restore_bitmode = 0xFFFF;
 
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;
 
            if (jtag_libusb_bulk_write(adapter, IN_EP,
                           (char *) ft232r_output + total_written,
                           bytes_to_write, 1000, &n) != ERROR_OK) {
                LOG_ERROR("usb bulk write failed");
                return ERROR_JTAG_DEVICE_ERROR;
            }
 
            total_written += n;
            rxfifo_free -= n;
        }
 
        /* Read */
        uint8_t reply[64];
        int n;
 
        if (jtag_libusb_bulk_read(adapter, OUT_EP, (char *) reply,
                      sizeof(reply), 1000, &n) != ERROR_OK) {
            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;
}
 
static void ft232r_increase_buf_size(size_t new_buf_size)
{
    uint8_t *new_buf_ptr;
    if (new_buf_size >= ft232r_buf_size) {
        new_buf_size += FT232R_BUF_SIZE_EXTRA;
        new_buf_ptr = realloc(ft232r_output, new_buf_size);
        if (new_buf_ptr) {
            ft232r_output = new_buf_ptr;
            ft232r_buf_size = new_buf_size;
        }
    }
}
 
static void ft232r_write(int tck, int tms, int tdi)
{
    unsigned int out_value = (1 << ntrst_gpio) | (1 << nsysrst_gpio);
    if (tck)
        out_value |= (1<<tck_gpio);
    if (tms)
        out_value |= (1<<tms_gpio);
    if (tdi)
        out_value |= (1<<tdi_gpio);
 
    ft232r_increase_buf_size(ft232r_output_len);
 
    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;
}
 
static void ft232r_reset(int trst, int srst)
{
    unsigned int out_value = (1 << ntrst_gpio) | (1 << nsysrst_gpio);
    LOG_DEBUG("ft232r_reset(%d,%d)", trst, srst);
 
    if (trst == 1)
        out_value &= ~(1<<ntrst_gpio);      /* switch /TRST low */
    else if (trst == 0)
        out_value |= (1<<ntrst_gpio);           /* switch /TRST high */
 
    if (srst == 1)
        out_value &= ~(1<<nsysrst_gpio);        /* switch /SYSRST low */
    else if (srst == 0)
        out_value |= (1<<nsysrst_gpio);     /* switch /SYSRST high */
 
    ft232r_increase_buf_size(ft232r_output_len);
 
    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, NULL, 0, 1000, NULL) != ERROR_OK) {
        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, NULL, &adapter, NULL)) {
        const char *ft232r_serial_desc = adapter_get_required_serial();
        LOG_ERROR("ft232r not found: vid=%04x, pid=%04x, serial=%s\n",
            ft232r_vid, ft232r_pid, (!ft232r_serial_desc) ? "[any]" : ft232r_serial_desc);
        return ERROR_JTAG_INIT_FAILED;
    }
 
    if (ft232r_restore_bitmode == 0xFFFF) /* serial port will not be restored after jtag: */
        libusb_detach_kernel_driver(adapter, 0);
    else /* serial port will be restored after jtag: */
        libusb_set_auto_detach_kernel_driver(adapter, 1); /* 1: DONT_DETACH_SIO_MODULE */
 
    if (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, NULL, 0, 1000, NULL) != ERROR_OK) {
        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, (1<<tck_gpio) | (1<<tdi_gpio) | (1<<tms_gpio) | (1<<ntrst_gpio) | (1<<nsysrst_gpio) | 0x400,
        0, NULL, 0, 1000, NULL) != ERROR_OK) {
        LOG_ERROR("cannot set sync bitbang mode");
        return ERROR_JTAG_INIT_FAILED;
    }
 
    /* Exactly 500 nsec between updates. */
    unsigned int 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, NULL, 0, 1000, NULL) != ERROR_OK) {
        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, NULL, 0, 1000, NULL) != ERROR_OK) {
        LOG_ERROR("unable to set latency timer");
        return ERROR_JTAG_INIT_FAILED;
    }
 
    ft232r_output = malloc(ft232r_buf_size);
    if (!ft232r_output) {
        LOG_ERROR("Unable to allocate memory for the buffer");
        return ERROR_JTAG_INIT_FAILED;
    }
 
    return ERROR_OK;
}
 
static int ft232r_quit(void)
{
    /* to restore serial port: set TXD RTS DTR as outputs, others as inputs, disable sync bit bang mode. */
    if (ft232r_restore_bitmode != 0xFFFF) {
        if (jtag_libusb_control_transfer(adapter,
            LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_RECIPIENT_DEVICE | LIBUSB_ENDPOINT_OUT,
            SIO_SET_BITMODE, ft232r_restore_bitmode,
            0, NULL, 0, 1000, NULL) != ERROR_OK) {
            LOG_ERROR("cannot set bitmode to restore serial port");
        }
    }
 
    if (libusb_release_interface(adapter, 0) != 0)
        LOG_ERROR("usb release interface failed");
 
    jtag_libusb_close(adapter);
 
    free(ft232r_output); /* free used memory */
    ft232r_output = NULL; /* reset pointer to memory */
    ft232r_buf_size = FT232R_BUF_SIZE_EXTRA; /* reset next initial buffer size */
 
    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;
}
 
static char *ft232r_bit_number_to_name(int bit)
{
    if (bit >= 0 && bit < FT232R_BIT_COUNT)
        return ft232r_bit_name_array[bit];
    return "?";
}
 
static int ft232r_bit_name_to_number(const char *name)
{
    int i;
    if (name[0] >= '0' && name[0] <= '9' && name[1] == '\0') {
        i = atoi(name);
        if (i >= 0 && i < FT232R_BIT_COUNT)
            return i;
    }
    for (i = 0; i < FT232R_BIT_COUNT; i++)
        if (strcasecmp(name, ft232r_bit_name_array[i]) == 0)
            return i;
    return -1;
}
 
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;
}
 
COMMAND_HANDLER(ft232r_handle_jtag_nums_command)
{
    if (CMD_ARGC == 4) {
        tck_gpio = ft232r_bit_name_to_number(CMD_ARGV[0]);
        tms_gpio = ft232r_bit_name_to_number(CMD_ARGV[1]);
        tdi_gpio = ft232r_bit_name_to_number(CMD_ARGV[2]);
        tdo_gpio = ft232r_bit_name_to_number(CMD_ARGV[3]);
    } else if (CMD_ARGC != 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    if (tck_gpio < 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
    if (tms_gpio < 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
    if (tdi_gpio < 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
    if (tdo_gpio < 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    command_print(CMD,
            "FT232R nums: TCK = %d %s, TMS = %d %s, TDI = %d %s, TDO = %d %s",
            tck_gpio, ft232r_bit_number_to_name(tck_gpio),
            tms_gpio, ft232r_bit_number_to_name(tms_gpio),
            tdi_gpio, ft232r_bit_number_to_name(tdi_gpio),
            tdo_gpio, ft232r_bit_number_to_name(tdo_gpio));
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(ft232r_handle_tck_num_command)
{
    if (CMD_ARGC == 1)
        tck_gpio = ft232r_bit_name_to_number(CMD_ARGV[0]);
    else if (CMD_ARGC != 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    if (tck_gpio < 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    command_print(CMD,
            "FT232R num: TCK = %d %s", tck_gpio, ft232r_bit_number_to_name(tck_gpio));
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(ft232r_handle_tms_num_command)
{
    if (CMD_ARGC == 1)
        tms_gpio = ft232r_bit_name_to_number(CMD_ARGV[0]);
    else if (CMD_ARGC != 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    if (tms_gpio < 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    command_print(CMD,
            "FT232R num: TMS = %d %s", tms_gpio, ft232r_bit_number_to_name(tms_gpio));
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(ft232r_handle_tdo_num_command)
{
    if (CMD_ARGC == 1)
        tdo_gpio = ft232r_bit_name_to_number(CMD_ARGV[0]);
    else if (CMD_ARGC != 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    if (tdo_gpio < 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    command_print(CMD,
            "FT232R num: TDO = %d %s", tdo_gpio, ft232r_bit_number_to_name(tdo_gpio));
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(ft232r_handle_tdi_num_command)
{
    if (CMD_ARGC == 1)
        tdi_gpio = ft232r_bit_name_to_number(CMD_ARGV[0]);
    else if (CMD_ARGC != 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    if (tdi_gpio < 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    command_print(CMD,
            "FT232R num: TDI = %d %s", tdi_gpio, ft232r_bit_number_to_name(tdi_gpio));
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(ft232r_handle_trst_num_command)
{
    if (CMD_ARGC == 1)
        ntrst_gpio = ft232r_bit_name_to_number(CMD_ARGV[0]);
    else if (CMD_ARGC != 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    if (ntrst_gpio < 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    command_print(CMD,
            "FT232R num: TRST = %d %s", ntrst_gpio, ft232r_bit_number_to_name(ntrst_gpio));
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(ft232r_handle_srst_num_command)
{
    if (CMD_ARGC == 1)
        nsysrst_gpio = ft232r_bit_name_to_number(CMD_ARGV[0]);
    else if (CMD_ARGC != 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    if (nsysrst_gpio < 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    command_print(CMD,
            "FT232R num: SRST = %d %s", nsysrst_gpio, ft232r_bit_number_to_name(nsysrst_gpio));
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(ft232r_handle_restore_serial_command)
{
    if (CMD_ARGC == 1)
        COMMAND_PARSE_NUMBER(u16, CMD_ARGV[0], ft232r_restore_bitmode);
    else if (CMD_ARGC != 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    command_print(CMD,
            "FT232R restore serial: 0x%04X (%s)",
            ft232r_restore_bitmode, ft232r_restore_bitmode == 0xFFFF ? "disabled" : "enabled");
 
    return ERROR_OK;
}
 
static const struct command_registration ft232r_subcommand_handlers[] = {
    {
        .name = "vid_pid",
        .handler = ft232r_handle_vid_pid_command,
        .mode = COMMAND_CONFIG,
        .help = "USB VID and PID of the adapter",
        .usage = "vid pid",
    },
    {
        .name = "jtag_nums",
        .handler = ft232r_handle_jtag_nums_command,
        .mode = COMMAND_CONFIG,
        .help = "gpio numbers for tck, tms, tdi, tdo. (in that order)",
        .usage = "<0-7|TXD-RI> <0-7|TXD-RI> <0-7|TXD-RI> <0-7|TXD-RI>",
    },
    {
        .name = "tck_num",
        .handler = ft232r_handle_tck_num_command,
        .mode = COMMAND_CONFIG,
        .help = "gpio number for tck.",
        .usage = "<0-7|TXD|RXD|RTS|CTS|DTR|DSR|DCD|RI>",
    },
    {
        .name = "tms_num",
        .handler = ft232r_handle_tms_num_command,
        .mode = COMMAND_CONFIG,
        .help = "gpio number for tms.",
        .usage = "<0-7|TXD|RXD|RTS|CTS|DTR|DSR|DCD|RI>",
    },
    {
        .name = "tdo_num",
        .handler = ft232r_handle_tdo_num_command,
        .mode = COMMAND_CONFIG,
        .help = "gpio number for tdo.",
        .usage = "<0-7|TXD|RXD|RTS|CTS|DTR|DSR|DCD|RI>",
    },
    {
        .name = "tdi_num",
        .handler = ft232r_handle_tdi_num_command,
        .mode = COMMAND_CONFIG,
        .help = "gpio number for tdi.",
        .usage = "<0-7|TXD|RXD|RTS|CTS|DTR|DSR|DCD|RI>",
    },
    {
        .name = "srst_num",
        .handler = ft232r_handle_srst_num_command,
        .mode = COMMAND_CONFIG,
        .help = "gpio number for srst.",
        .usage = "<0-7|TXD|RXD|RTS|CTS|DTR|DSR|DCD|RI>",
    },
    {
        .name = "trst_num",
        .handler = ft232r_handle_trst_num_command,
        .mode = COMMAND_CONFIG,
        .help = "gpio number for trst.",
        .usage = "<0-7|TXD|RXD|RTS|CTS|DTR|DSR|DCD|RI>",
    },
    {
        .name = "restore_serial",
        .handler = ft232r_handle_restore_serial_command,
        .mode = COMMAND_CONFIG,
        .help = "bitmode control word that restores serial port.",
        .usage = "bitmode_control_word",
    },
    COMMAND_REGISTRATION_DONE
};
 
static const struct command_registration ft232r_command_handlers[] = {
    {
        .name = "ft232r",
        .mode = COMMAND_ANY,
        .help = "perform ft232r management",
        .chain = ft232r_subcommand_handlers,
        .usage = "",
    },
    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());
}
 
static int syncbb_execute_tms(struct jtag_command *cmd)
{
    unsigned int num_bits = cmd->cmd.tms->num_bits;
    const uint8_t *bits = cmd->cmd.tms->bits;
 
    LOG_DEBUG_IO("TMS: %u bits", num_bits);
 
    int tms = 0;
    for (unsigned int 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)
{
    unsigned 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(unsigned int num_cycles)
{
 
    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 (unsigned int 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);
}
 
static void syncbb_stableclocks(unsigned int num_cycles)
{
    int tms = (tap_get_state() == TAP_RESET ? 1 : 0);
 
    /* send num_cycles clocks onto the cable */
    for (unsigned int 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 & (1<<tdo_gpio))
                buffer[bytec] |= bcval;
            else
                buffer[bytec] &= ~bcval;
        }
}
 
static int syncbb_execute_queue(struct jtag_command *cmd_queue)
{
    struct jtag_command *cmd = cmd_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 %u 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: %u 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;
                free(buffer);
                break;
 
            case JTAG_SLEEP:
                LOG_DEBUG_IO("sleep %" PRIu32, 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;
}
 
static struct jtag_interface ft232r_interface = {
    .supported = DEBUG_CAP_TMS_SEQ,
    .execute_queue = syncbb_execute_queue,
};
 
struct adapter_driver ft232r_adapter_driver = {
    .name = "ft232r",
    .transports = jtag_only,
    .commands = ft232r_command_handlers,
 
    .init = ft232r_init,
    .quit = ft232r_quit,
    .speed = ft232r_speed,
    .khz = ft232r_khz,
    .speed_div = ft232r_speed_div,
 
    .jtag_ops = &ft232r_interface,
};