openjtag.c

Go to the documentation of this file.

// SPDX-License-Identifier: GPL-2.0-or-later
 
/*******************************************************************************
 *   Driver for OpenJTAG Project (www.openjtag.org)                            *
 *   Compatible with libftdi drivers.                                          *
 *                                                                             *
 *   Cypress CY7C65215 support                                                 *
 *   Copyright (C) 2015 Vianney le Clément de Saint-Marcq, Essensium NV        *
 *                      <vianney.leclement@essensium.com>                      *
 *                                                                             *
 *   Copyright (C) 2010 by Ivan Meleca <mileca@gmail.com>                      *
 *                                                                             *
 *   Copyright (C) 2013 by Ryan Corbin, GlueLogix Inc. <corbin.ryan@gmail.com> *
 *   Updated to work with OpenOCD v0.7.0. Fixed libftdi read speed issue.      *
 *                                                                             *
 *   Based on usb_blaster.c                                                    *
 *   Copyright (C) 2009 Catalin Patulea                                        *
 *   Copyright (C) 2006 Kolja Waschk                                           *
 *                                                                             *
 *   And jlink.c                                                               *
 *   Copyright (C) 2008 by Spencer Oliver                                      *
 *   spen@spen-soft.co.uk                                                      *
 ***************************************************************************/
 
/***************************************************************************
 * Version 1.0  Tested on a MCBSTM32 board using a Cortex-M3 (stm32f103x), *
 *              GDB and Eclipse under Linux (Ubuntu 10.04)                 *
 *                                                                         *
 ***************************************************************************/
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
 
#include <jtag/interface.h>
#include <jtag/commands.h>
#include "libusb_helper.h"
 
static enum {
    OPENJTAG_VARIANT_STANDARD,
    OPENJTAG_VARIANT_CY7C65215,
} openjtag_variant = OPENJTAG_VARIANT_STANDARD;
 
static const char * const openjtag_variant_names[] = {
    "standard",
    "cy7c65215",
    NULL
};
 
/*
 * OpenJTAG-OpenOCD state conversion
 */
typedef enum openjtag_tap_state {
    OPENJTAG_TAP_INVALID    = -1,
    OPENJTAG_TAP_RESET  = 0,
    OPENJTAG_TAP_IDLE   = 1,
    OPENJTAG_TAP_SELECT_DR  = 2,
    OPENJTAG_TAP_CAPTURE_DR = 3,
    OPENJTAG_TAP_SHIFT_DR   = 4,
    OPENJTAG_TAP_EXIT1_DR   = 5,
    OPENJTAG_TAP_PAUSE_DR   = 6,
    OPENJTAG_TAP_EXIT2_DR   = 7,
    OPENJTAG_TAP_UPDATE_DR  = 8,
    OPENJTAG_TAP_SELECT_IR  = 9,
    OPENJTAG_TAP_CAPURE_IR  = 10,
    OPENJTAG_TAP_SHIFT_IR   = 11,
    OPENJTAG_TAP_EXIT1_IR   = 12,
    OPENJTAG_TAP_PAUSE_IR   = 13,
    OPENJTAG_TAP_EXIT2_IR   = 14,
    OPENJTAG_TAP_UPDATE_IR  = 15,
} openjtag_tap_state_t;
 
/* OPENJTAG access library includes */
#include "libftdi_helper.h"
 
/* OpenJTAG vid/pid */
static uint16_t openjtag_vid = 0x0403;
static uint16_t openjtag_pid = 0x6001;
 
static char *openjtag_device_desc;
 
static struct ftdi_context ftdic;
 
#define OPENJTAG_BUFFER_SIZE        504
#define OPENJTAG_MAX_PENDING_RESULTS    256
 
struct openjtag_scan_result {
    uint32_t bits;          /* Length in bits*/
    struct scan_command *command;   /* Corresponding scan command */
    uint8_t *buffer;
};
 
/* USB RX/TX buffers */
static int usb_tx_buf_offs;
static uint8_t usb_tx_buf[OPENJTAG_BUFFER_SIZE];
static uint32_t usb_rx_buf_len;
static uint8_t usb_rx_buf[OPENJTAG_BUFFER_SIZE];
 
/* Pending readings */
static struct openjtag_scan_result openjtag_scan_result_buffer[OPENJTAG_MAX_PENDING_RESULTS];
static int openjtag_scan_result_count;
 
static struct libusb_device_handle *usbh;
 
/* CY7C65215 model only */
#define CY7C65215_JTAG_REQUEST  0x40  /* bmRequestType: vendor host-to-device */
#define CY7C65215_JTAG_ENABLE   0xD0  /* bRequest: enable JTAG */
#define CY7C65215_JTAG_DISABLE  0xD1  /* bRequest: disable JTAG */
#define CY7C65215_JTAG_READ     0xD2  /* bRequest: read buffer */
#define CY7C65215_JTAG_WRITE    0xD3  /* bRequest: write buffer */
 
#define CY7C65215_USB_TIMEOUT   100
 
static const uint16_t cy7c65215_vids[] = {0x04b4, 0};
static const uint16_t cy7c65215_pids[] = {0x0007, 0};
 
#define CY7C65215_JTAG_CLASS     0xff
#define CY7C65215_JTAG_SUBCLASS  0x04
 
static unsigned int ep_in, ep_out;
 
#ifdef _DEBUG_USB_COMMS_
 
#define DEBUG_TYPE_READ     0
#define DEBUG_TYPE_WRITE    1
#define DEBUG_TYPE_OCD_READ 2
#define DEBUG_TYPE_BUFFER   3
 
#define LINE_LEN  16
static void openjtag_debug_buffer(uint8_t *buffer, int length, uint8_t type)
{
    char line[128];
    char s[4];
    int i;
    int j;
 
    switch (type) {
        case DEBUG_TYPE_READ:
            sprintf(line, "USB READ %d bytes", length);
            break;
        case DEBUG_TYPE_WRITE:
            sprintf(line, "USB WRITE %d bytes", length);
            break;
        case DEBUG_TYPE_OCD_READ:
            sprintf(line, "TO OpenOCD %d bytes", length);
            break;
        case DEBUG_TYPE_BUFFER:
            sprintf(line, "Buffer %d bytes", length);
            break;
    }
 
    LOG_DEBUG("%s", line);
 
    for (i = 0; i < length; i += LINE_LEN) {
        switch (type) {
            case DEBUG_TYPE_READ:
                sprintf(line, "USB READ: %04x", i);
                break;
            case DEBUG_TYPE_WRITE:
                sprintf(line, "USB WRITE: %04x", i);
                break;
            case DEBUG_TYPE_OCD_READ:
                sprintf(line, "TO OpenOCD: %04x", i);
                break;
            case DEBUG_TYPE_BUFFER:
                sprintf(line, "BUFFER: %04x", i);
                break;
        }
 
        for (j = i; j < i + LINE_LEN && j < length; j++) {
            sprintf(s, " %02x", buffer[j]);
            strcat(line, s);
        }
        LOG_DEBUG("%s", line);
    }
 
}
 
#endif
 
static int8_t openjtag_get_tap_state(int8_t state)
{
 
    switch (state) {
        case TAP_DREXIT2:   return OPENJTAG_TAP_EXIT2_DR;
        case TAP_DREXIT1:   return OPENJTAG_TAP_EXIT1_DR;
        case TAP_DRSHIFT:   return OPENJTAG_TAP_SHIFT_DR;
        case TAP_DRPAUSE:   return OPENJTAG_TAP_PAUSE_DR;
        case TAP_IRSELECT:  return OPENJTAG_TAP_SELECT_IR;
        case TAP_DRUPDATE:  return OPENJTAG_TAP_UPDATE_DR;
        case TAP_DRCAPTURE: return OPENJTAG_TAP_CAPTURE_DR;
        case TAP_DRSELECT:  return OPENJTAG_TAP_SELECT_DR;
        case TAP_IREXIT2:   return OPENJTAG_TAP_EXIT2_IR;
        case TAP_IREXIT1:   return OPENJTAG_TAP_EXIT1_IR;
        case TAP_IRSHIFT:   return OPENJTAG_TAP_SHIFT_IR;
        case TAP_IRPAUSE:   return OPENJTAG_TAP_PAUSE_IR;
        case TAP_IDLE:      return OPENJTAG_TAP_IDLE;
        case TAP_IRUPDATE:  return OPENJTAG_TAP_UPDATE_IR;
        case TAP_IRCAPTURE: return OPENJTAG_TAP_CAPURE_IR;
        case TAP_RESET:     return OPENJTAG_TAP_RESET;
        case TAP_INVALID:
        default:            return OPENJTAG_TAP_INVALID;
    }
}
 
static int openjtag_buf_write_standard(
    uint8_t *buf, int size, uint32_t *bytes_written)
{
    int retval;
#ifdef _DEBUG_USB_COMMS_
    openjtag_debug_buffer(buf, size, DEBUG_TYPE_WRITE);
#endif
 
    retval = ftdi_write_data(&ftdic, buf, size);
    if (retval < 0) {
        *bytes_written = 0;
        LOG_ERROR("ftdi_write_data: %s", ftdi_get_error_string(&ftdic));
        return ERROR_JTAG_DEVICE_ERROR;
    }
 
    *bytes_written = retval;
 
    return ERROR_OK;
}
 
static int openjtag_buf_write_cy7c65215(
    uint8_t *buf, int size, uint32_t *bytes_written)
{
    int ret;
 
#ifdef _DEBUG_USB_COMMS_
    openjtag_debug_buffer(buf, size, DEBUG_TYPE_WRITE);
#endif
 
    if (size == 0) {
        *bytes_written = 0;
        return ERROR_OK;
    }
 
    ret = jtag_libusb_control_transfer(usbh, CY7C65215_JTAG_REQUEST,
                                       CY7C65215_JTAG_WRITE, size, 0,
                                       NULL, 0, CY7C65215_USB_TIMEOUT, NULL);
    if (ret != ERROR_OK) {
        LOG_ERROR("vendor command failed");
        return ret;
    }
 
    if (jtag_libusb_bulk_write(usbh, ep_out, (char *)buf, size,
                   CY7C65215_USB_TIMEOUT, &ret)) {
        LOG_ERROR("bulk write failed, error");
        return ERROR_JTAG_DEVICE_ERROR;
    }
    *bytes_written = ret;
 
    return ERROR_OK;
}
 
static int openjtag_buf_write(
    uint8_t *buf, int size, uint32_t *bytes_written)
{
    switch (openjtag_variant) {
    case OPENJTAG_VARIANT_CY7C65215:
        return openjtag_buf_write_cy7c65215(buf, size, bytes_written);
    default:
        return openjtag_buf_write_standard(buf, size, bytes_written);
    }
}
 
static int openjtag_buf_read_standard(
    uint8_t *buf, uint32_t qty, uint32_t *bytes_read)
{
 
    int retval;
    int timeout = 5;
 
    *bytes_read = 0;
 
    while ((*bytes_read < qty) && timeout--) {
        retval = ftdi_read_data(&ftdic, buf + *bytes_read,
                qty - *bytes_read);
        if (retval < 0) {
            *bytes_read = 0;
            LOG_DEBUG_IO("ftdi_read_data: %s",
                    ftdi_get_error_string(&ftdic));
            return ERROR_JTAG_DEVICE_ERROR;
        }
        *bytes_read += retval;
    }
 
#ifdef _DEBUG_USB_COMMS_
    openjtag_debug_buffer(buf, *bytes_read, DEBUG_TYPE_READ);
#endif
 
    return ERROR_OK;
}
 
static int openjtag_buf_read_cy7c65215(
    uint8_t *buf, uint32_t qty, uint32_t *bytes_read)
{
    int ret;
 
    if (qty == 0) {
        *bytes_read = 0;
        goto out;
    }
 
    ret = jtag_libusb_control_transfer(usbh, CY7C65215_JTAG_REQUEST,
                                       CY7C65215_JTAG_READ, qty, 0,
                                       NULL, 0, CY7C65215_USB_TIMEOUT, NULL);
    if (ret != ERROR_OK) {
        LOG_ERROR("vendor command failed");
        return ret;
    }
 
    if (jtag_libusb_bulk_read(usbh, ep_in, (char *)buf, qty,
                  CY7C65215_USB_TIMEOUT, &ret)) {
        LOG_ERROR("bulk read failed, error");
        return ERROR_JTAG_DEVICE_ERROR;
    }
    *bytes_read = ret;
 
out:
#ifdef _DEBUG_USB_COMMS_
    openjtag_debug_buffer(buf, *bytes_read, DEBUG_TYPE_READ);
#endif
 
    return ERROR_OK;
}
 
static int openjtag_buf_read(uint8_t *buf, uint32_t qty, uint32_t *bytes_read)
{
    switch (openjtag_variant) {
    case OPENJTAG_VARIANT_CY7C65215:
        return openjtag_buf_read_cy7c65215(buf, qty, bytes_read);
    default:
        return openjtag_buf_read_standard(buf, qty, bytes_read);
    }
}
 
static int openjtag_sendcommand(uint8_t cmd)
{
    uint32_t written;
    return openjtag_buf_write(&cmd, 1, &written);
}
 
static int openjtag_speed(int speed)
{
    int clockcmd;
    switch (speed) {
        case 48000:
            clockcmd = 0x00;
            break;
        case 24000:
            clockcmd = 0x20;
            break;
        case 12000:
            clockcmd = 0x40;
            break;
        case 6000:
            clockcmd = 0x60;
            break;
        case 3000:
            clockcmd = 0x80;
            break;
        case 1500:
            clockcmd = 0xA0;
            break;
        case 750:
            clockcmd = 0xC0;
            break;
        case 375:
            clockcmd = 0xE0;
            break;
        default:
            clockcmd = 0xE0;
            LOG_WARNING("adapter speed not recognized, reverting to 375 kHz");
            break;
    }
    openjtag_sendcommand(clockcmd);
 
    return ERROR_OK;
}
 
static int openjtag_init_standard(void)
{
    uint8_t latency_timer;
 
    /* Open by device description */
    if (!openjtag_device_desc) {
        LOG_WARNING("no openjtag device description specified, "
                "using default 'Open JTAG Project'");
        openjtag_device_desc = "Open JTAG Project";
    }
 
    if (ftdi_init(&ftdic) < 0)
        return ERROR_JTAG_INIT_FAILED;
 
    /* context, vendor id, product id, description, serial id */
    if (ftdi_usb_open_desc(&ftdic, openjtag_vid, openjtag_pid, openjtag_device_desc, NULL) < 0) {
        LOG_ERROR("unable to open ftdi device: %s", ftdic.error_str);
        return ERROR_JTAG_INIT_FAILED;
    }
 
    if (ftdi_usb_reset(&ftdic) < 0) {
        LOG_ERROR("unable to reset ftdi device");
        return ERROR_JTAG_INIT_FAILED;
    }
 
    if (ftdi_set_latency_timer(&ftdic, 2) < 0) {
        LOG_ERROR("unable to set latency timer");
        return ERROR_JTAG_INIT_FAILED;
    }
 
    if (ftdi_get_latency_timer(&ftdic, &latency_timer) < 0) {
        LOG_ERROR("unable to get latency timer");
        return ERROR_JTAG_INIT_FAILED;
    }
    LOG_DEBUG("current latency timer: %u", latency_timer);
 
    ftdi_disable_bitbang(&ftdic);
    /* was (3000000 / 4) with a comment about a bug in libftdi when using high baudrate */
    if (ftdi_set_baudrate(&ftdic, 3000000) < 0) {
        LOG_ERROR("Can't set baud rate to max: %s",
            ftdi_get_error_string(&ftdic));
        return ERROR_JTAG_DEVICE_ERROR;
    }
 
    if (ftdi_tcioflush(&ftdic) < 0) {
        LOG_ERROR("ftdi flush: %s", ftdic.error_str);
        return ERROR_JTAG_INIT_FAILED;
    }
 
    return ERROR_OK;
}
 
static int openjtag_init_cy7c65215(void)
{
    int ret;
 
    usbh = NULL;
    ret = jtag_libusb_open(cy7c65215_vids, cy7c65215_pids, NULL, &usbh, NULL);
    if (ret != ERROR_OK) {
        LOG_ERROR("unable to open cy7c65215 device");
        goto err;
    }
 
    ret = jtag_libusb_choose_interface(usbh, &ep_in, &ep_out,
                                       CY7C65215_JTAG_CLASS,
                                       CY7C65215_JTAG_SUBCLASS, -1, LIBUSB_TRANSFER_TYPE_BULK);
    if (ret != ERROR_OK) {
        LOG_ERROR("unable to claim JTAG interface");
        goto err;
    }
 
    ret = jtag_libusb_control_transfer(usbh,
                                       CY7C65215_JTAG_REQUEST,
                                       CY7C65215_JTAG_ENABLE,
                                       0, 0, NULL, 0, CY7C65215_USB_TIMEOUT, NULL);
    if (ret != ERROR_OK) {
        LOG_ERROR("could not enable JTAG module");
        goto err;
    }
 
    return ERROR_OK;
 
err:
    if (usbh)
        jtag_libusb_close(usbh);
    return ret;
}
 
static int openjtag_init(void)
{
    int ret;
 
    usb_tx_buf_offs = 0;
    usb_rx_buf_len = 0;
    openjtag_scan_result_count = 0;
 
    switch (openjtag_variant) {
    case OPENJTAG_VARIANT_CY7C65215:
        ret = openjtag_init_cy7c65215();
        break;
    default:
        ret = openjtag_init_standard();
    }
    if (ret != ERROR_OK)
        return ret;
 
    openjtag_speed(375); /* Start at slowest adapter speed */
    openjtag_sendcommand(0x75); /* MSB */
 
    return ERROR_OK;
}
 
static int openjtag_quit_standard(void)
{
    ftdi_usb_close(&ftdic);
    ftdi_deinit(&ftdic);
 
    return ERROR_OK;
}
 
static int openjtag_quit_cy7c65215(void)
{
    int ret;
 
    ret = jtag_libusb_control_transfer(usbh,
                                       CY7C65215_JTAG_REQUEST,
                                       CY7C65215_JTAG_DISABLE,
                                       0, 0, NULL, 0, CY7C65215_USB_TIMEOUT, NULL);
    if (ret != ERROR_OK)
        LOG_WARNING("could not disable JTAG module");
 
    jtag_libusb_close(usbh);
 
    return ERROR_OK;
}
 
static int openjtag_quit(void)
{
    switch (openjtag_variant) {
    case OPENJTAG_VARIANT_CY7C65215:
        return openjtag_quit_cy7c65215();
    default:
        return openjtag_quit_standard();
    }
}
 
static void openjtag_write_tap_buffer(void)
{
    uint32_t written;
    uint32_t rx_expected = 0;
 
    /* calculate expected number of return bytes */
    for (int tx_offs = 0; tx_offs < usb_tx_buf_offs; tx_offs++) {
        if ((usb_tx_buf[tx_offs] & 0x0F) == 6) {
            rx_expected++;
            tx_offs++;
        } else if ((usb_tx_buf[tx_offs] & 0x0F) == 2) {
            rx_expected++;
        }
    }
 
    openjtag_buf_write(usb_tx_buf, usb_tx_buf_offs, &written);
    openjtag_buf_read(usb_rx_buf, rx_expected, &usb_rx_buf_len);
 
    usb_tx_buf_offs = 0;
}
 
static int openjtag_execute_tap_queue(void)
{
    openjtag_write_tap_buffer();
 
    int res_count = 0;
 
    if (openjtag_scan_result_count && usb_rx_buf_len) {
 
        int count;
        int rx_offs = 0;
        int len;
 
        /* for every pending result */
        while (res_count < openjtag_scan_result_count) {
 
            /* get sent bits */
            len = openjtag_scan_result_buffer[res_count].bits;
 
            count = 0;
 
            uint8_t *buffer = openjtag_scan_result_buffer[res_count].buffer;
 
            while (len > 0) {
                if (len <= 8 && openjtag_variant != OPENJTAG_VARIANT_CY7C65215) {
                    LOG_DEBUG_IO("bits < 8 buf = 0x%X, will be 0x%X",
                        usb_rx_buf[rx_offs], usb_rx_buf[rx_offs] >> (8 - len));
                    buffer[count] = usb_rx_buf[rx_offs] >> (8 - len);
                    len = 0;
                } else {
                    buffer[count] = usb_rx_buf[rx_offs];
                    len -= 8;
                }
 
                rx_offs++;
                count++;
            }
 
#ifdef _DEBUG_USB_COMMS_
            openjtag_debug_buffer(buffer,
                DIV_ROUND_UP(openjtag_scan_result_buffer[res_count].bits, 8), DEBUG_TYPE_OCD_READ);
#endif
            jtag_read_buffer(buffer, openjtag_scan_result_buffer[res_count].command);
 
            free(openjtag_scan_result_buffer[res_count].buffer);
 
            res_count++;
        }
    }
 
    openjtag_scan_result_count = 0;
 
    return ERROR_OK;
}
 
static void openjtag_add_byte(char buf)
{
 
    if (usb_tx_buf_offs == OPENJTAG_BUFFER_SIZE) {
        LOG_DEBUG_IO("Forcing execute_tap_queue");
        LOG_DEBUG_IO("TX Buff offs=%d", usb_tx_buf_offs);
        openjtag_execute_tap_queue();
    }
 
    usb_tx_buf[usb_tx_buf_offs] = buf;
    usb_tx_buf_offs++;
}
 
static void openjtag_add_scan(uint8_t *buffer, int length, struct scan_command *scan_cmd)
{
 
    /* Ensure space to send long chains */
    /* We add two byte for each eight (or less) bits, one for command, one for data */
    if (usb_tx_buf_offs + (DIV_ROUND_UP(length, 8) * 2) >= OPENJTAG_BUFFER_SIZE) {
        LOG_DEBUG_IO("Forcing execute_tap_queue from scan");
        LOG_DEBUG_IO("TX Buff offs=%d len=%d", usb_tx_buf_offs, DIV_ROUND_UP(length, 8) * 2);
        openjtag_execute_tap_queue();
    }
 
    openjtag_scan_result_buffer[openjtag_scan_result_count].bits = length;
    openjtag_scan_result_buffer[openjtag_scan_result_count].command = scan_cmd;
    openjtag_scan_result_buffer[openjtag_scan_result_count].buffer = buffer;
 
    uint8_t command;
    uint8_t bits;
    int count = 0;
    while (length) {
 
        /* write command */
        command = 6;
 
        /* last bits? */
        if (length <= 8) {
            /* tms high */
            command |= (1 << 4);
 
            /* bits to transfer */
            bits = (length - 1);
            command |= bits << 5;
            length = 0;
        } else {
            /* whole byte */
 
            /* bits to transfer */
            command |= (7 << 5);
            length -= 8;
        }
 
        openjtag_add_byte(command);
        openjtag_add_byte(buffer[count]);
        count++;
    }
 
    openjtag_scan_result_count++;
}
 
static void openjtag_execute_reset(struct jtag_command *cmd)
{
 
    LOG_DEBUG_IO("reset trst: %i srst %i",
            cmd->cmd.reset->trst, cmd->cmd.reset->srst);
 
    uint8_t buf = 0x00;
 
    /* Pull SRST low for 5 TCLK cycles */
    if (cmd->cmd.reset->srst) {
        buf |= 0x04;
        buf |= 0x05 << 4;
        openjtag_add_byte(buf);
    }
}
 
static void openjtag_execute_sleep(struct jtag_command *cmd)
{
    jtag_sleep(cmd->cmd.sleep->us);
}
 
static void openjtag_set_state(uint8_t openocd_state)
{
    uint8_t state = openjtag_get_tap_state(openocd_state);
 
    uint8_t buf = 0;
 
    if (state != OPENJTAG_TAP_RESET) {
        buf = 0x01;
        buf |= state << 4;
    } else {
        /* Force software TLR */
        buf = 0x03;
    }
 
    openjtag_add_byte(buf);
}
 
static void openjtag_execute_statemove(struct jtag_command *cmd)
{
    LOG_DEBUG_IO("state move to %i", cmd->cmd.statemove->end_state);
 
    tap_set_end_state(cmd->cmd.statemove->end_state);
 
    openjtag_set_state(cmd->cmd.statemove->end_state);
 
    tap_set_state(tap_get_end_state());
}
 
 
static void openjtag_execute_scan(struct jtag_command *cmd)
{
 
    int scan_size, old_state;
    uint8_t *buffer;
 
    LOG_DEBUG_IO("scan ends in %s", tap_state_name(cmd->cmd.scan->end_state));
 
    /* get scan info */
    tap_set_end_state(cmd->cmd.scan->end_state);
    scan_size = jtag_build_buffer(cmd->cmd.scan, &buffer);
 
#ifdef _DEBUG_USB_COMMS_
    openjtag_debug_buffer(buffer, (scan_size + 7) / 8, DEBUG_TYPE_BUFFER);
#endif
    /* set state */
    old_state = tap_get_end_state();
    openjtag_set_state(cmd->cmd.scan->ir_scan ? TAP_IRSHIFT : TAP_DRSHIFT);
    tap_set_state(cmd->cmd.scan->ir_scan ? TAP_IRSHIFT : TAP_DRSHIFT);
    tap_set_end_state(old_state);
 
    openjtag_add_scan(buffer, scan_size, cmd->cmd.scan);
 
    openjtag_set_state(cmd->cmd.scan->ir_scan ? TAP_IRPAUSE : TAP_DRPAUSE);
    tap_set_state(cmd->cmd.scan->ir_scan ? TAP_IRPAUSE : TAP_DRPAUSE);
 
    if (tap_get_state() != tap_get_end_state()) {
        openjtag_set_state(tap_get_end_state());
        tap_set_state(tap_get_end_state());
    }
}
 
static void openjtag_execute_runtest(struct jtag_command *cmd)
{
 
    tap_state_t end_state = cmd->cmd.runtest->end_state;
    tap_set_end_state(end_state);
 
    /* only do a state_move when we're not already in IDLE */
    if (tap_get_state() != TAP_IDLE) {
        openjtag_set_state(TAP_IDLE);
        tap_set_state(TAP_IDLE);
    }
 
    if (openjtag_variant != OPENJTAG_VARIANT_CY7C65215 ||
        cmd->cmd.runtest->num_cycles) {
        uint8_t command;
        unsigned int num_cycles = cmd->cmd.runtest->num_cycles;
 
        do {
            const unsigned int num_cycles_cmd = MIN(num_cycles, 16);
 
            command = 7;
            command |= ((num_cycles_cmd - 1) & 0x0F) << 4;
 
            openjtag_add_byte(command);
            num_cycles -= num_cycles_cmd;
        } while (num_cycles > 0);
    }
 
    tap_set_end_state(end_state);
    if (tap_get_end_state() != tap_get_state()) {
        openjtag_set_state(end_state);
        tap_set_state(end_state);
    }
}
 
static void openjtag_execute_command(struct jtag_command *cmd)
{
    LOG_DEBUG_IO("openjtag_execute_command %i", cmd->type);
    switch (cmd->type) {
    case JTAG_RESET:
            openjtag_execute_reset(cmd);
            break;
    case JTAG_SLEEP:
            openjtag_execute_sleep(cmd);
            break;
    case JTAG_TLR_RESET:
            openjtag_execute_statemove(cmd);
            break;
    case JTAG_SCAN:
            openjtag_execute_scan(cmd);
            break;
    case JTAG_RUNTEST:
            openjtag_execute_runtest(cmd);
            break;
    case JTAG_PATHMOVE:
        /* jlink_execute_pathmove(cmd); break; */
    default:
        LOG_ERROR("BUG: unknown Open JTAG command type encountered");
        exit(-1);
    }
}
 
static int openjtag_execute_queue(struct jtag_command *cmd_queue)
{
    struct jtag_command *cmd = cmd_queue;
 
    while (cmd) {
        openjtag_execute_command(cmd);
        cmd = cmd->next;
    }
 
    return openjtag_execute_tap_queue();
}
 
static int openjtag_speed_div(int speed, int *khz)
{
    *khz = speed;
 
    return ERROR_OK;
}
 
static int openjtag_khz(int khz, int *jtag_speed)
{
 
    if (khz >= 48000)
        *jtag_speed = 48000;
    else if (khz >= 24000)
        *jtag_speed = 24000;
    else if (khz >= 12000)
        *jtag_speed = 12000;
    else if (khz >= 6000)
        *jtag_speed = 6000;
    else if (khz >= 3000)
        *jtag_speed = 3000;
    else if (khz >= 1500)
        *jtag_speed = 1500;
    else if (khz >= 750)
        *jtag_speed = 750;
    else
        *jtag_speed = 375;
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(openjtag_handle_device_desc_command)
{
    if (CMD_ARGC == 1)
        openjtag_device_desc = strdup(CMD_ARGV[0]);
    else
        LOG_ERROR("require exactly one argument to "
                  "openjtag_device_desc <description>");
    return ERROR_OK;
}
 
COMMAND_HANDLER(openjtag_handle_variant_command)
{
    if (CMD_ARGC == 1) {
        const char * const *name = openjtag_variant_names;
        int variant = 0;
        for (; *name; name++, variant++) {
            if (strcasecmp(CMD_ARGV[0], *name) == 0) {
                openjtag_variant = variant;
                return ERROR_OK;
            }
        }
        LOG_ERROR("unknown openjtag variant '%s'", CMD_ARGV[0]);
    } else {
        LOG_ERROR("require exactly one argument to "
                "openjtag_variant <variant>");
    }
    return ERROR_OK;
}
 
COMMAND_HANDLER(openjtag_handle_vid_pid_command)
{
    if (CMD_ARGC != 2)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    COMMAND_PARSE_NUMBER(u16, CMD_ARGV[0], openjtag_vid);
    COMMAND_PARSE_NUMBER(u16, CMD_ARGV[1], openjtag_pid);
 
    return ERROR_OK;
}
 
static const struct command_registration openjtag_subcommand_handlers[] = {
    {
        .name = "device_desc",
        .handler = openjtag_handle_device_desc_command,
        .mode = COMMAND_CONFIG,
        .help = "set the USB device description of the OpenJTAG",
        .usage = "description-string",
    },
    {
        .name = "variant",
        .handler = openjtag_handle_variant_command,
        .mode = COMMAND_CONFIG,
        .help = "set the OpenJTAG variant",
        .usage = "variant-string",
    },
    {
        .name = "vid_pid",
        .handler = openjtag_handle_vid_pid_command,
        .mode = COMMAND_CONFIG,
        .help = "USB VID and PID of the adapter",
        .usage = "vid pid",
    },
    COMMAND_REGISTRATION_DONE
};
 
static const struct command_registration openjtag_command_handlers[] = {
    {
        .name = "openjtag",
        .mode = COMMAND_ANY,
        .help = "perform openjtag management",
        .chain = openjtag_subcommand_handlers,
        .usage = "",
    },
    COMMAND_REGISTRATION_DONE
};
 
static struct jtag_interface openjtag_interface = {
    .execute_queue = openjtag_execute_queue,
};
 
struct adapter_driver openjtag_adapter_driver = {
    .name = "openjtag",
    .transports = jtag_only,
    .commands = openjtag_command_handlers,
 
    .init = openjtag_init,
    .quit = openjtag_quit,
    .speed = openjtag_speed,
    .khz = openjtag_khz,
    .speed_div = openjtag_speed_div,
 
    .jtag_ops = &openjtag_interface,
};