usb_blaster.c

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// SPDX-License-Identifier: GPL-2.0-or-later
 
/*
 *   Driver for USB-JTAG, Altera USB-Blaster and compatibles
 *
 *   Inspired from original code from Kolja Waschk's USB-JTAG project
 *   (http://www.ixo.de/info/usb_jtag/), and from openocd project.
 *
 *   Copyright (C) 2013 Franck Jullien franck.jullien@gmail.com
 *   Copyright (C) 2012 Robert Jarzmik robert.jarzmik@free.fr
 *   Copyright (C) 2011 Ali Lown ali@lown.me.uk
 *   Copyright (C) 2009 Catalin Patulea cat@vv.carleton.ca
 *   Copyright (C) 2006 Kolja Waschk usbjtag@ixo.de
 *
 */
 
/*
 * The following information is originally from Kolja Waschk's USB-JTAG,
 * where it was obtained by reverse engineering an Altera USB-Blaster.
 * See http://www.ixo.de/info/usb_jtag/ for USB-Blaster block diagram and
 * usb_jtag-20080705-1200.zip#usb_jtag/host/openocd for protocol.
 *
 * The same information is also on the UrJTAG mediawiki, with some additional
 * notes on bits marked as "unknown" by usb_jtag.
 * (http://sourceforge.net/apps/mediawiki/urjtag/index.php?
 *    title=Cable_Altera_USB-Blaster)
 *
 * USB-JTAG, Altera USB-Blaster and compatibles are typically implemented as
 * an FTDIChip FT245 followed by a CPLD which handles a two-mode protocol:
 *
 *            _________
 *           |         |
 *           | AT93C46 |
 *           |_________|
 *            __|__________    _________
 *           |             |  |         |
 *      USB__| FTDI 245BM  |__| EPM7064 |__JTAG (B_TDO,B_TDI,B_TMS,B_TCK)
 *           |_____________|  |_________|
 *            __|__________    _|___________
 *           |             |  |             |
 *           | 6 MHz XTAL  |  | 24 MHz Osc. |
 *           |_____________|  |_____________|
 *
 * USB-JTAG, Altera USB-Blaster II are typically implemented as a Cypress
 * EZ-USB FX2LP followed by a CPLD.
 *            _____________    _________
 *           |             |  |         |
 *      USB__| EZ-USB FX2  |__| EPM570  |__JTAG (B_TDO,B_TDI,B_TMS,B_TCK)
 *           |_____________|  |_________|
 *            __|__________
 *           |             |
 *           | 24 MHz XTAL |
 *           |_____________|
 */
 
#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 <helper/replacements.h>
#include "ublast_access.h"
 
/* system includes */
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/time.h>
#include <time.h>
 
/* Size of USB endpoint max packet size, ie. 64 bytes */
#define MAX_PACKET_SIZE 64
/*
 * Size of data buffer that holds bytes in byte-shift mode.
 * This buffer can hold multiple USB packets aligned to
 * MAX_PACKET_SIZE bytes boundaries.
 * BUF_LEN must be grater than or equal MAX_PACKET_SIZE.
 */
#define BUF_LEN 4096
 
/* USB-Blaster II specific command */
#define CMD_COPY_TDO_BUFFER 0x5F
 
enum gpio_steer {
    FIXED_0 = 0,
    FIXED_1,
    SRST,
    TRST,
};
 
struct ublast_info {
    enum gpio_steer pin6;
    enum gpio_steer pin8;
    int tms;
    int tdi;
    bool trst_asserted;
    bool srst_asserted;
    uint8_t buf[BUF_LEN];
    int bufidx;
 
    char *lowlevel_name;
    struct ublast_lowlevel *drv;
    uint16_t ublast_vid, ublast_pid;
    uint16_t ublast_vid_uninit, ublast_pid_uninit;
    int flags;
    char *firmware_path;
};
 
/*
 * Global device control
 */
static struct ublast_info info = {
    .ublast_vid = 0x09fb, /* Altera */
    .ublast_pid = 0x6001, /* USB-Blaster */
    .lowlevel_name = NULL,
    .srst_asserted = false,
    .trst_asserted = false,
    .pin6 = FIXED_1,
    .pin8 = FIXED_1,
};
 
/*
 * Available lowlevel drivers (FTDI, libusb, ...)
 */
struct drvs_map {
    char *name;
    struct ublast_lowlevel *(*drv_register)(void);
};
 
static struct drvs_map lowlevel_drivers_map[] = {
#if BUILD_USB_BLASTER
    { .name = "ftdi", .drv_register = ublast_register_ftdi },
#endif
#if BUILD_USB_BLASTER_2
    { .name = "ublast2", .drv_register = ublast2_register_libusb },
#endif
    { NULL, NULL },
};
 
/*
 * Access functions to lowlevel driver, agnostic of libftdi/libftdxx
 */
static char *hexdump(uint8_t *buf, unsigned int size)
{
    unsigned int i;
    char *str = calloc(size * 2 + 1, 1);
 
    for (i = 0; i < size; i++)
        sprintf(str + 2*i, "%02x", buf[i]);
    return str;
}
 
static int ublast_buf_read(uint8_t *buf, unsigned size, uint32_t *bytes_read)
{
    int ret = info.drv->read(info.drv, buf, size, bytes_read);
    char *str = hexdump(buf, *bytes_read);
 
    LOG_DEBUG_IO("(size=%d, buf=[%s]) -> %" PRIu32, size, str,
              *bytes_read);
    free(str);
    return ret;
}
 
static int ublast_buf_write(uint8_t *buf, int size, uint32_t *bytes_written)
{
    int ret = info.drv->write(info.drv, buf, size, bytes_written);
    char *str = hexdump(buf, *bytes_written);
 
    LOG_DEBUG_IO("(size=%d, buf=[%s]) -> %" PRIu32, size, str,
              *bytes_written);
    free(str);
    return ret;
}
 
static int nb_buf_remaining(void)
{
    return BUF_LEN - info.bufidx;
}
 
static void ublast_flush_buffer(void)
{
    uint32_t retlen;
    int nb = info.bufidx, ret = ERROR_OK;
 
    while (ret == ERROR_OK && nb > 0) {
        ret = ublast_buf_write(info.buf, nb, &retlen);
        nb -= retlen;
    }
    info.bufidx = 0;
}
 
/*
 * Actually, the USB-Blaster offers a byte-shift mode to transmit up to 504 data
 * bits (bidirectional) in a single USB packet. A header byte has to be sent as
 * the first byte in a packet with the following meaning:
 *
 *   Bit 7 (0x80): Must be set to indicate byte-shift mode.
 *   Bit 6 (0x40): If set, the USB-Blaster will also read data, not just write.
 *   Bit 5..0:     Define the number N of following bytes
 *
 * All N following bytes will then be clocked out serially on TDI. If Bit 6 was
 * set, it will afterwards return N bytes with TDO data read while clocking out
 * the TDI data. LSB of the first byte after the header byte will appear first
 * on TDI.
 */
 
/* Simple bit banging mode:
 *
 *   Bit 7 (0x80): Must be zero (see byte-shift mode above)
 *   Bit 6 (0x40): If set, you will receive a byte indicating the state of TDO
 *                 in return.
 *   Bit 5 (0x20): Output Enable/LED.
 *   Bit 4 (0x10): TDI Output.
 *   Bit 3 (0x08): nCS Output (not used in JTAG mode).
 *   Bit 2 (0x04): nCE Output (not used in JTAG mode).
 *   Bit 1 (0x02): TMS Output.
 *   Bit 0 (0x01): TCK Output.
 *
 * For transmitting a single data bit, you need to write two bytes (one for
 * setting up TDI/TMS/TCK=0, and one to trigger TCK high with same TDI/TMS
 * held). Up to 64 bytes can be combined in a single USB packet.
 * It isn't possible to read a data without transmitting data.
 */
 
#define TCK     (1 << 0)
#define TMS     (1 << 1)
#define NCE     (1 << 2)
#define NCS     (1 << 3)
#define TDI     (1 << 4)
#define LED     (1 << 5)
#define READ        (1 << 6)
#define SHMODE      (1 << 7)
#define READ_TDO    (1 << 0)
 
static void ublast_queue_byte(uint8_t abyte)
{
    if (nb_buf_remaining() < 1)
        ublast_flush_buffer();
    info.buf[info.bufidx++] = abyte;
    if (nb_buf_remaining() == 0)
        ublast_flush_buffer();
    LOG_DEBUG_IO("(byte=0x%02x)", abyte);
}
 
static bool ublast_compute_pin(enum gpio_steer steer)
{
    switch (steer) {
    case FIXED_0:
        return 0;
    case FIXED_1:
        return 1;
    case SRST:
        return !info.srst_asserted;
    case TRST:
        return !info.trst_asserted;
    default:
        return 1;
    }
}
 
static uint8_t ublast_build_out(enum scan_type type)
{
    uint8_t abyte = 0;
 
    abyte |= info.tms ? TMS : 0;
    abyte |= ublast_compute_pin(info.pin6) ? NCE : 0;
    abyte |= ublast_compute_pin(info.pin8) ? NCS : 0;
    abyte |= info.tdi ? TDI : 0;
    abyte |= LED;
    if (type == SCAN_IN || type == SCAN_IO)
        abyte |= READ;
    return abyte;
}
 
static void ublast_reset(int trst, int srst)
{
    uint8_t out_value;
 
    info.trst_asserted = trst;
    info.srst_asserted = srst;
    out_value = ublast_build_out(SCAN_OUT);
    ublast_queue_byte(out_value);
    ublast_flush_buffer();
}
 
static void ublast_clock_tms(int tms)
{
    uint8_t out;
 
    LOG_DEBUG_IO("(tms=%d)", !!tms);
    info.tms = !!tms;
    info.tdi = 0;
    out = ublast_build_out(SCAN_OUT);
    ublast_queue_byte(out);
    ublast_queue_byte(out | TCK);
}
 
static void ublast_idle_clock(void)
{
    uint8_t out = ublast_build_out(SCAN_OUT);
 
    LOG_DEBUG_IO(".");
    ublast_queue_byte(out);
}
 
static void ublast_clock_tdi(int tdi, enum scan_type type)
{
    uint8_t out;
 
    LOG_DEBUG_IO("(tdi=%d)",  !!tdi);
    info.tdi = !!tdi;
 
    out = ublast_build_out(SCAN_OUT);
    ublast_queue_byte(out);
 
    out = ublast_build_out(type);
    ublast_queue_byte(out | TCK);
}
 
static void ublast_clock_tdi_flip_tms(int tdi, enum scan_type type)
{
    uint8_t out;
 
    LOG_DEBUG_IO("(tdi=%d)", !!tdi);
    info.tdi = !!tdi;
    info.tms = !info.tms;
 
    out = ublast_build_out(SCAN_OUT);
    ublast_queue_byte(out);
 
    out = ublast_build_out(type);
    ublast_queue_byte(out | TCK);
 
    out = ublast_build_out(SCAN_OUT);
    ublast_queue_byte(out);
}
 
static void ublast_queue_bytes(uint8_t *bytes, int nb_bytes)
{
    if (info.bufidx + nb_bytes > BUF_LEN) {
        LOG_ERROR("buggy code, should never queue more that %d bytes",
              info.bufidx + nb_bytes);
        exit(-1);
    }
    LOG_DEBUG_IO("(nb_bytes=%d, bytes=[0x%02x, ...])", nb_bytes,
              bytes ? bytes[0] : 0);
    if (bytes)
        memcpy(&info.buf[info.bufidx], bytes, nb_bytes);
    else
        memset(&info.buf[info.bufidx], 0, nb_bytes);
    info.bufidx += nb_bytes;
    if (nb_buf_remaining() == 0)
        ublast_flush_buffer();
}
 
static void ublast_tms_seq(const uint8_t *bits, int nb_bits, int skip)
{
    int i;
 
    LOG_DEBUG_IO("(bits=%02x..., nb_bits=%d)", bits[0], nb_bits);
    for (i = skip; i < nb_bits; i++)
        ublast_clock_tms((bits[i / 8] >> (i % 8)) & 0x01);
    ublast_idle_clock();
}
 
static void ublast_tms(struct tms_command *cmd)
{
    LOG_DEBUG_IO("(num_bits=%d)", cmd->num_bits);
    ublast_tms_seq(cmd->bits, cmd->num_bits, 0);
}
 
static void ublast_path_move(struct pathmove_command *cmd)
{
    int i;
 
    LOG_DEBUG_IO("(num_states=%d, last_state=%d)",
          cmd->num_states, cmd->path[cmd->num_states - 1]);
    for (i = 0; i < cmd->num_states; i++) {
        if (tap_state_transition(tap_get_state(), false) == cmd->path[i])
            ublast_clock_tms(0);
        if (tap_state_transition(tap_get_state(), true) == cmd->path[i])
            ublast_clock_tms(1);
        tap_set_state(cmd->path[i]);
    }
    ublast_idle_clock();
}
 
static void ublast_state_move(tap_state_t state, int skip)
{
    uint8_t tms_scan;
    int tms_len;
 
    LOG_DEBUG_IO("(from %s to %s)", tap_state_name(tap_get_state()),
          tap_state_name(state));
    if (tap_get_state() == state)
        return;
    tms_scan = tap_get_tms_path(tap_get_state(), state);
    tms_len = tap_get_tms_path_len(tap_get_state(), state);
    ublast_tms_seq(&tms_scan, tms_len, skip);
    tap_set_state(state);
}
 
static int ublast_read_byteshifted_tdos(uint8_t *buf, int nb_bytes)
{
    uint32_t retlen;
    int ret = ERROR_OK;
 
    LOG_DEBUG_IO("%s(buf=%p, num_bits=%d)", __func__, buf, nb_bytes * 8);
    ublast_flush_buffer();
    while (ret == ERROR_OK && nb_bytes > 0) {
        ret = ublast_buf_read(buf, nb_bytes, &retlen);
        nb_bytes -= retlen;
    }
    return ret;
}
 
static int ublast_read_bitbang_tdos(uint8_t *buf, int nb_bits)
{
    int nb1 = nb_bits;
    int i, ret = ERROR_OK;
    uint32_t retlen;
    uint8_t tmp[8];
 
    LOG_DEBUG_IO("%s(buf=%p, num_bits=%d)", __func__, buf, nb_bits);
 
    /*
     * Ensure all previous bitbang writes were issued to the dongle, so that
     * it returns back the read values.
     */
    ublast_flush_buffer();
 
    ret = ublast_buf_read(tmp, nb1, &retlen);
    for (i = 0; ret == ERROR_OK && i < nb1; i++)
        if (tmp[i] & READ_TDO)
            *buf |= (1 << i);
        else
            *buf &= ~(1 << i);
    return ret;
}
 
static void ublast_queue_tdi(uint8_t *bits, int nb_bits, enum scan_type scan)
{
    int nb8 = nb_bits / 8;
    int nb1 = nb_bits % 8;
    int nbfree_in_packet, i, trans = 0, read_tdos;
    uint8_t *tdos = calloc(1, nb_bits / 8 + 1);
    static uint8_t byte0[BUF_LEN];
 
    /*
     * As the last TDI bit should always be output in bitbang mode in order
     * to activate the TMS=1 transition to EXIT_?R state. Therefore a
     * situation where nb_bits is a multiple of 8 is handled as follows:
     * - the number of TDI shifted out in "byteshift mode" is 8 less than
     *   nb_bits
     * - nb1 = 8
     * This ensures that nb1 is never 0, and allows the TMS transition.
     */
    if (nb8 > 0 && nb1 == 0) {
        nb8--;
        nb1 = 8;
    }
 
    read_tdos = (scan == SCAN_IN || scan == SCAN_IO);
    for (i = 0; i < nb8; i += trans) {
        /*
         * Calculate number of bytes to fill USB packet of size MAX_PACKET_SIZE
         */
        nbfree_in_packet = (MAX_PACKET_SIZE - (info.bufidx%MAX_PACKET_SIZE));
        trans = MIN(nbfree_in_packet - 1, nb8 - i);
 
        /*
         * Queue a byte-shift mode transmission, with as many bytes as
         * is possible with regard to :
         *  - current filling level of write buffer
         *  - remaining bytes to write in byte-shift mode
         */
        if (read_tdos)
            ublast_queue_byte(SHMODE | READ | trans);
        else
            ublast_queue_byte(SHMODE | trans);
        if (bits)
            ublast_queue_bytes(&bits[i], trans);
        else
            ublast_queue_bytes(byte0, trans);
        if (read_tdos) {
            if (info.flags & COPY_TDO_BUFFER)
                ublast_queue_byte(CMD_COPY_TDO_BUFFER);
            ublast_read_byteshifted_tdos(&tdos[i], trans);
        }
    }
 
    /*
     * Queue the remaining TDI bits in bitbang mode.
     */
    for (i = 0; i < nb1; i++) {
        int tdi = bits ? bits[nb8 + i / 8] & (1 << i) : 0;
        if (bits && i == nb1 - 1)
            ublast_clock_tdi_flip_tms(tdi, scan);
        else
            ublast_clock_tdi(tdi, scan);
    }
    if (nb1 && read_tdos) {
        if (info.flags & COPY_TDO_BUFFER)
            ublast_queue_byte(CMD_COPY_TDO_BUFFER);
        ublast_read_bitbang_tdos(&tdos[nb8], nb1);
    }
 
    if (bits)
        memcpy(bits, tdos, DIV_ROUND_UP(nb_bits, 8));
    free(tdos);
 
    /*
     * Ensure clock is in lower state
     */
    ublast_idle_clock();
}
 
static void ublast_runtest(int cycles, tap_state_t state)
{
    LOG_DEBUG_IO("%s(cycles=%i, end_state=%d)", __func__, cycles, state);
 
    ublast_state_move(TAP_IDLE, 0);
    ublast_queue_tdi(NULL, cycles, SCAN_OUT);
    ublast_state_move(state, 0);
}
 
static void ublast_stableclocks(int cycles)
{
    LOG_DEBUG_IO("%s(cycles=%i)", __func__, cycles);
    ublast_queue_tdi(NULL, cycles, SCAN_OUT);
}
 
static int ublast_scan(struct scan_command *cmd)
{
    int scan_bits;
    uint8_t *buf = NULL;
    enum scan_type type;
    int ret = ERROR_OK;
    static const char * const type2str[] = { "", "SCAN_IN", "SCAN_OUT", "SCAN_IO" };
    char *log_buf = NULL;
 
    type = jtag_scan_type(cmd);
    scan_bits = jtag_build_buffer(cmd, &buf);
 
    if (cmd->ir_scan)
        ublast_state_move(TAP_IRSHIFT, 0);
    else
        ublast_state_move(TAP_DRSHIFT, 0);
 
    log_buf = hexdump(buf, DIV_ROUND_UP(scan_bits, 8));
    LOG_DEBUG_IO("%s(scan=%s, type=%s, bits=%d, buf=[%s], end_state=%d)", __func__,
          cmd->ir_scan ? "IRSCAN" : "DRSCAN",
          type2str[type],
          scan_bits, log_buf, cmd->end_state);
    free(log_buf);
 
    ublast_queue_tdi(buf, scan_bits, type);
 
    ret = jtag_read_buffer(buf, cmd);
    free(buf);
    /*
     * ublast_queue_tdi sends the last bit with TMS=1. We are therefore
     * already in Exit1-DR/IR and have to skip the first step on our way
     * to end_state.
     */
    ublast_state_move(cmd->end_state, 1);
    return ret;
}
 
static void ublast_usleep(int us)
{
    LOG_DEBUG_IO("%s(us=%d)",  __func__, us);
    jtag_sleep(us);
}
 
static void ublast_initial_wipeout(void)
{
    static uint8_t tms_reset = 0xff;
    uint8_t out_value;
    uint32_t retlen;
    int i;
 
    out_value = ublast_build_out(SCAN_OUT);
    for (i = 0; i < BUF_LEN; i++)
        info.buf[i] = out_value | ((i % 2) ? TCK : 0);
 
    /*
     * Flush USB-Blaster queue fifos
     *  - empty the write FIFO (128 bytes)
     *  - empty the read FIFO (384 bytes)
     */
    ublast_buf_write(info.buf, BUF_LEN, &retlen);
    /*
     * Put JTAG in RESET state (five 1 on TMS)
     */
    ublast_tms_seq(&tms_reset, 5, 0);
    tap_set_state(TAP_RESET);
}
 
static int ublast_execute_queue(struct jtag_command *cmd_queue)
{
    struct jtag_command *cmd;
    static int first_call = 1;
    int ret = ERROR_OK;
 
    if (first_call) {
        first_call--;
        ublast_initial_wipeout();
    }
 
    for (cmd = cmd_queue; ret == ERROR_OK && cmd;
         cmd = cmd->next) {
        switch (cmd->type) {
        case JTAG_RESET:
            ublast_reset(cmd->cmd.reset->trst, cmd->cmd.reset->srst);
            break;
        case JTAG_RUNTEST:
            ublast_runtest(cmd->cmd.runtest->num_cycles,
                       cmd->cmd.runtest->end_state);
            break;
        case JTAG_STABLECLOCKS:
            ublast_stableclocks(cmd->cmd.stableclocks->num_cycles);
            break;
        case JTAG_TLR_RESET:
            ublast_state_move(cmd->cmd.statemove->end_state, 0);
            break;
        case JTAG_PATHMOVE:
            ublast_path_move(cmd->cmd.pathmove);
            break;
        case JTAG_TMS:
            ublast_tms(cmd->cmd.tms);
            break;
        case JTAG_SLEEP:
            ublast_usleep(cmd->cmd.sleep->us);
            break;
        case JTAG_SCAN:
            ret = ublast_scan(cmd->cmd.scan);
            break;
        default:
            LOG_ERROR("BUG: unknown JTAG command type 0x%X",
                  cmd->type);
            ret = ERROR_FAIL;
            break;
        }
    }
 
    ublast_flush_buffer();
    return ret;
}
 
static int ublast_init(void)
{
    int ret, i;
 
    for (i = 0; lowlevel_drivers_map[i].name; i++) {
        if (info.lowlevel_name) {
            if (!strcmp(lowlevel_drivers_map[i].name, info.lowlevel_name)) {
                info.drv = lowlevel_drivers_map[i].drv_register();
                if (!info.drv) {
                    LOG_ERROR("Error registering lowlevel driver \"%s\"",
                          info.lowlevel_name);
                    return ERROR_JTAG_DEVICE_ERROR;
                }
                break;
            }
        } else {
            info.drv = lowlevel_drivers_map[i].drv_register();
            if (info.drv) {
                info.lowlevel_name = strdup(lowlevel_drivers_map[i].name);
                LOG_INFO("No lowlevel driver configured, using %s", info.lowlevel_name);
                break;
            }
        }
    }
 
    if (!info.drv) {
        LOG_ERROR("No lowlevel driver available");
        return ERROR_JTAG_DEVICE_ERROR;
    }
 
    /*
     * Register the lowlevel driver
     */
    info.drv->ublast_vid = info.ublast_vid;
    info.drv->ublast_pid = info.ublast_pid;
    info.drv->ublast_vid_uninit = info.ublast_vid_uninit;
    info.drv->ublast_pid_uninit = info.ublast_pid_uninit;
    info.drv->firmware_path = info.firmware_path;
 
    info.flags |= info.drv->flags;
 
    ret = info.drv->open(info.drv);
 
    /*
     * Let lie here : the TAP is in an unknown state, but the first
     * execute_queue() will trigger a ublast_initial_wipeout(), which will
     * put the TAP in RESET.
     */
    tap_set_state(TAP_RESET);
    return ret;
}
 
static int ublast_quit(void)
{
    uint8_t byte0 = 0;
    uint32_t retlen;
 
    ublast_buf_write(&byte0, 1, &retlen);
    return info.drv->close(info.drv);
}
 
COMMAND_HANDLER(ublast_handle_vid_pid_command)
{
    if (CMD_ARGC > 4) {
        LOG_WARNING("ignoring extra IDs in ublast_vid_pid "
                    "(maximum is 2 pairs)");
        CMD_ARGC = 4;
    }
 
    if (CMD_ARGC >= 2) {
        COMMAND_PARSE_NUMBER(u16, CMD_ARGV[0], info.ublast_vid);
        COMMAND_PARSE_NUMBER(u16, CMD_ARGV[1], info.ublast_pid);
    } else {
        LOG_WARNING("incomplete ublast_vid_pid configuration");
    }
 
    if (CMD_ARGC == 4) {
        COMMAND_PARSE_NUMBER(u16, CMD_ARGV[2], info.ublast_vid_uninit);
        COMMAND_PARSE_NUMBER(u16, CMD_ARGV[3], info.ublast_pid_uninit);
    } else {
        LOG_WARNING("incomplete ublast_vid_pid configuration");
    }
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(ublast_handle_pin_command)
{
    uint8_t out_value;
    const char * const pin_name = CMD_ARGV[0];
    enum gpio_steer *steer = NULL;
    static const char * const pin_val_str[] = {
        [FIXED_0] = "0",
        [FIXED_1] = "1",
        [SRST] = "SRST driven",
        [TRST] = "TRST driven",
    };
 
    if (CMD_ARGC > 2) {
        LOG_ERROR("%s takes exactly one or two arguments", CMD_NAME);
        return ERROR_COMMAND_SYNTAX_ERROR;
    }
 
    if (!strcmp(pin_name, "pin6"))
        steer = &info.pin6;
    if (!strcmp(pin_name, "pin8"))
        steer = &info.pin8;
    if (!steer) {
        LOG_ERROR("%s: pin name must be \"pin6\" or \"pin8\"",
              CMD_NAME);
        return ERROR_COMMAND_SYNTAX_ERROR;
    }
 
    if (CMD_ARGC == 1) {
        LOG_INFO("%s: %s is set as %s\n", CMD_NAME, pin_name,
             pin_val_str[*steer]);
    }
 
    if (CMD_ARGC == 2) {
        const char * const pin_value = CMD_ARGV[1];
        char val = pin_value[0];
 
        if (strlen(pin_value) > 1)
            val = '?';
        switch (tolower((unsigned char)val)) {
        case '0':
            *steer = FIXED_0;
            break;
        case '1':
            *steer = FIXED_1;
            break;
        case 't':
            *steer = TRST;
            break;
        case 's':
            *steer = SRST;
            break;
        default:
            LOG_ERROR("%s: pin value must be 0, 1, s (SRST) or t (TRST)",
                pin_value);
            return ERROR_COMMAND_SYNTAX_ERROR;
        }
 
        if (info.drv) {
            out_value = ublast_build_out(SCAN_OUT);
            ublast_queue_byte(out_value);
            ublast_flush_buffer();
        }
    }
    return ERROR_OK;
}
 
COMMAND_HANDLER(ublast_handle_lowlevel_drv_command)
{
    if (CMD_ARGC != 1)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    info.lowlevel_name = strdup(CMD_ARGV[0]);
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(ublast_firmware_command)
{
    if (CMD_ARGC != 1)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    info.firmware_path = strdup(CMD_ARGV[0]);
 
    return ERROR_OK;
}
 
 
static const struct command_registration ublast_subcommand_handlers[] = {
    {
        .name = "vid_pid",
        .handler = ublast_handle_vid_pid_command,
        .mode = COMMAND_CONFIG,
        .help = "the vendor ID and product ID of the USB-Blaster and "
            "vendor ID and product ID of the uninitialized device "
            "for USB-Blaster II",
        .usage = "vid pid vid_uninit pid_uninit",
    },
    {
        .name = "lowlevel_driver",
        .handler = ublast_handle_lowlevel_drv_command,
        .mode = COMMAND_CONFIG,
        .help = "set the lowlevel access for the USB Blaster (ftdi, ublast2)",
        .usage = "(ftdi|ublast2)",
    },
    {
        .name = "pin",
        .handler = ublast_handle_pin_command,
        .mode = COMMAND_ANY,
        .help = "show or set pin state for the unused GPIO pins",
        .usage = "(pin6|pin8) (0|1|s|t)",
    },
        {
        .name = "firmware",
        .handler = &ublast_firmware_command,
        .mode = COMMAND_CONFIG,
        .help = "configure the USB-Blaster II firmware location",
        .usage = "path/to/blaster_xxxx.hex",
    },
    COMMAND_REGISTRATION_DONE
};
 
static const struct command_registration ublast_command_handlers[] = {
    {
        .name = "usb_blaster",
        .mode = COMMAND_ANY,
        .help = "perform usb_blaster management",
        .chain = ublast_subcommand_handlers,
        .usage = "",
    },
    COMMAND_REGISTRATION_DONE
};
 
static struct jtag_interface usb_blaster_interface = {
    .supported = DEBUG_CAP_TMS_SEQ,
    .execute_queue = ublast_execute_queue,
};
 
struct adapter_driver usb_blaster_adapter_driver = {
    .name = "usb_blaster",
    .transports = jtag_only,
    .commands = ublast_command_handlers,
 
    .init = ublast_init,
    .quit = ublast_quit,
 
    .jtag_ops = &usb_blaster_interface,
};