stlink: dequeue CSW write only if it doesn't change csw_default

[openocd.git] / src / jtag / drivers / rlink.c

/***************************************************************************
 *   Copyright (C) 2005 by Dominic Rath                                    *
 *   Dominic.Rath@gmx.de                                                   *
 *                                                                         *
 *   Copyright (C) 2007,2008 Øyvind Harboe                                 *
 *   oyvind.harboe@zylin.com                                               *
 *                                                                         *
 *   Copyright (C) 2008 Rob Brown, Lou Deluxe                              *
 *   rob@cobbleware.com, lou.openocd012@fixit.nospammail.net               *
 *                                                                         *
 *   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

/* project specific includes */
#include <jtag/interface.h>
#include <jtag/commands.h>
#include "helper/replacements.h"
#include "rlink.h"
#include "rlink_st7.h"
#include "rlink_ep1_cmd.h"
#include "rlink_dtc_cmd.h"
#include "libusb_helper.h"

/* This feature is made useless by running the DTC all the time.  When automatic, the LED is on
 *whenever the DTC is running.  Otherwise, USB messages are sent to turn it on and off. */
#undef AUTOMATIC_BUSY_LED

/* This feature may require derating the speed due to reduced hold time. */
#undef USE_HARDWARE_SHIFTER_FOR_TMS

#define INTERFACE_NAME          "RLink"

#define USB_IDVENDOR            (0x138e)
#define USB_IDPRODUCT           (0x9000)

#define USB_EP1OUT_ADDR         (0x01)
#define USB_EP1OUT_SIZE         (16)
#define USB_EP1IN_ADDR          (USB_EP1OUT_ADDR | 0x80)
#define USB_EP1IN_SIZE          (USB_EP1OUT_SIZE)

#define USB_EP2OUT_ADDR         (0x02)
#define USB_EP2OUT_SIZE         (64)
#define USB_EP2IN_ADDR          (USB_EP2OUT_ADDR | 0x80)
#define USB_EP2IN_SIZE          (USB_EP2OUT_SIZE)
#define USB_EP2BANK_SIZE        (512)

#define USB_TIMEOUT_MS          (3 * 1000)

#define DTC_STATUS_POLL_BYTE    (ST7_USB_BUF_EP0OUT + 0xff)

#define ST7_PD_NBUSY_LED                ST7_PD0
#define ST7_PD_NRUN_LED                 ST7_PD1
/* low enables VPP at adapter header, high connects it to GND instead */
#define ST7_PD_VPP_SEL                  ST7_PD6
/* low: VPP = 12v, high: VPP <= 5v */
#define ST7_PD_VPP_SHDN                 ST7_PD7

/* These pins are connected together */
#define ST7_PE_ADAPTER_SENSE_IN         ST7_PE3
#define ST7_PE_ADAPTER_SENSE_OUT        ST7_PE4

/* Symbolic mapping between port pins and numbered IO lines */
#define ST7_PA_IO1      ST7_PA1
#define ST7_PA_IO2      ST7_PA2
#define ST7_PA_IO4      ST7_PA4
#define ST7_PA_IO8      ST7_PA6
#define ST7_PA_IO10     ST7_PA7
#define ST7_PB_IO5      ST7_PB5
#define ST7_PC_IO9      ST7_PC1
#define ST7_PC_IO3      ST7_PC2
#define ST7_PC_IO7      ST7_PC3
#define ST7_PE_IO6      ST7_PE5

/* Symbolic mapping between numbered IO lines and adapter signals */
#define ST7_PA_RTCK     ST7_PA_IO0
#define ST7_PA_NTRST    ST7_PA_IO1
#define ST7_PC_TDI      ST7_PC_IO3
#define ST7_PA_DBGRQ    ST7_PA_IO4
#define ST7_PB_NSRST    ST7_PB_IO5
#define ST7_PE_TMS      ST7_PE_IO6
#define ST7_PC_TCK      ST7_PC_IO7
#define ST7_PC_TDO      ST7_PC_IO9
#define ST7_PA_DBGACK   ST7_PA_IO10

static struct libusb_device_handle *hdev;

/*
 * ep1 commands are up to USB_EP1OUT_SIZE bytes in length.
 * This function takes care of zeroing the unused bytes before sending the packet.
 * Any reply packet is not handled by this function.
 */
static int ep1_generic_commandl(struct libusb_device_handle *hdev_param, size_t length, ...)
{
        uint8_t usb_buffer[USB_EP1OUT_SIZE];
        uint8_t *usb_buffer_p;
        va_list ap;
        int usb_ret;
        int transferred;

        if (length > sizeof(usb_buffer))
                length = sizeof(usb_buffer);

        usb_buffer_p = usb_buffer;

        va_start(ap, length);
        while (length > 0) {
                *usb_buffer_p++ = va_arg(ap, int);
                length--;
        }

        memset(
                usb_buffer_p,
                0,
                sizeof(usb_buffer) - (usb_buffer_p - usb_buffer)
                );

        usb_ret = jtag_libusb_bulk_write(
                        hdev_param,
                        USB_EP1OUT_ADDR,
                        (char *)usb_buffer, sizeof(usb_buffer),
                        USB_TIMEOUT_MS,
                        &transferred
                        );

        if (usb_ret != ERROR_OK)
                return usb_ret;
        return transferred;
}

#if 0
static ssize_t ep1_memory_read(
        struct libusb_device_handle *hdev_param, uint16_t addr,
        size_t length, uint8_t *buffer)
{
        uint8_t usb_buffer[USB_EP1OUT_SIZE];
        int usb_ret;
        size_t remain;
        ssize_t count;
        int transferred;

        usb_buffer[0] = EP1_CMD_MEMORY_READ;
        memset(
                usb_buffer + 4,
                0,
                sizeof(usb_buffer) - 4
                );

        remain = length;
        count = 0;

        while (remain) {
                if (remain > sizeof(usb_buffer))
                        length = sizeof(usb_buffer);
                else
                        length = remain;

                usb_buffer[1] = addr >> 8;
                usb_buffer[2] = addr;
                usb_buffer[3] = length;

                usb_ret = jtag_libusb_bulk_write(
                                hdev_param, USB_EP1OUT_ADDR,
                                (char *)usb_buffer, sizeof(usb_buffer),
                                USB_TIMEOUT_MS,
                                &transferred
                                );

                if (usb_ret != ERROR_OK || transferred < (int)sizeof(usb_buffer))
                        break;

                usb_ret = jtag_libusb_bulk_read(
                                hdev_param, USB_EP1IN_ADDR,
                                (char *)buffer, length,
                                USB_TIMEOUT_MS,
                                &transferred
                                );

                if (usb_ret != ERROR_OK || transferred < (int)length)
                        break;

                addr += length;
                buffer += length;
                count += length;
                remain -= length;
        }

        return count;
}
#endif

static ssize_t ep1_memory_write(struct libusb_device_handle *hdev_param, uint16_t addr,
        size_t length, uint8_t const *buffer)
{
        uint8_t usb_buffer[USB_EP1OUT_SIZE];
        int usb_ret;
        size_t remain;
        ssize_t count;

        usb_buffer[0] = EP1_CMD_MEMORY_WRITE;

        remain = length;
        count = 0;

        while (remain) {
                if (remain > (sizeof(usb_buffer) - 4))
                        length = (sizeof(usb_buffer) - 4);
                else
                        length = remain;

                usb_buffer[1] = addr >> 8;
                usb_buffer[2] = addr;
                usb_buffer[3] = length;
                memcpy(
                        usb_buffer + 4,
                        buffer,
                        length
                        );
                memset(
                        usb_buffer + 4 + length,
                        0,
                        sizeof(usb_buffer) - 4 - length
                        );

                int transferred;

                usb_ret = jtag_libusb_bulk_write(
                                hdev_param, USB_EP1OUT_ADDR,
                                (char *)usb_buffer, sizeof(usb_buffer),
                                USB_TIMEOUT_MS,
                                &transferred
                                );

                if (usb_ret != ERROR_OK || transferred < (int)sizeof(usb_buffer))
                        break;

                addr += length;
                buffer += length;
                count += length;
                remain -= length;
        }

        return count;
}


#if 0
static ssize_t ep1_memory_writel(struct libusb_device_handle *hdev_param, uint16_t addr,
        size_t length, ...)
{
        uint8_t buffer[USB_EP1OUT_SIZE - 4];
        uint8_t *buffer_p;
        va_list ap;
        size_t remain;

        if (length > sizeof(buffer))
                length = sizeof(buffer);

        remain = length;
        buffer_p = buffer;

        va_start(ap, length);
        while (remain > 0) {
                *buffer_p++ = va_arg(ap, int);
                remain--;
        }

        return ep1_memory_write(hdev_param, addr, length, buffer);
}
#endif

#define DTCLOAD_COMMENT         (0)
#define DTCLOAD_ENTRY           (1)
#define DTCLOAD_LOAD            (2)
#define DTCLOAD_RUN                     (3)
#define DTCLOAD_LUT_START       (4)
#define DTCLOAD_LUT                     (5)

#define DTC_LOAD_BUFFER         ST7_USB_BUF_EP2UIDO

/* This gets set by the DTC loader */
static uint8_t dtc_entry_download;

/* The buffer is specially formatted to represent a valid image to load into the DTC. */
static int dtc_load_from_buffer(struct libusb_device_handle *hdev_param, const uint8_t *buffer,
                size_t length)
{
        struct header_s {
                uint8_t type;
                uint8_t length;
        };

        int usb_err;
        struct header_s *header;
        uint8_t lut_start = 0xc0;

        dtc_entry_download = 0;

        /* Stop the DTC before loading anything. */
        usb_err = ep1_generic_commandl(
                        hdev_param, 1,
                        EP1_CMD_DTC_STOP
                        );
        if (usb_err < 0)
                return usb_err;

        while (length) {
                if (length < sizeof(*header)) {
                        LOG_ERROR("Malformed DTC image");
                        exit(1);
                }

                header = (struct header_s *)buffer;
                buffer += sizeof(*header);
                length -= sizeof(*header);

                if (length < (size_t)header->length + 1) {
                        LOG_ERROR("Malformed DTC image");
                        exit(1);
                }

                switch (header->type) {
                        case DTCLOAD_COMMENT:
                                break;

                        case DTCLOAD_ENTRY:
                                /* store entry addresses somewhere */
                                if (!strncmp("download", (char *)buffer + 1, 8))
                                        dtc_entry_download = buffer[0];
                                break;

                        case DTCLOAD_LOAD:
                                /* Send the DTC program to ST7 RAM. */
                                usb_err = ep1_memory_write(
                                                hdev_param,
                                                DTC_LOAD_BUFFER,
                                                header->length + 1, buffer
                                        );
                                if (usb_err < 0)
                                        return usb_err;

                                /* Load it into the DTC. */
                                usb_err = ep1_generic_commandl(
                                                hdev_param, 3,
                                                EP1_CMD_DTC_LOAD,
                                                (DTC_LOAD_BUFFER >> 8),
                                                DTC_LOAD_BUFFER
                                        );
                                if (usb_err < 0)
                                        return usb_err;

                                break;

                        case DTCLOAD_RUN:
                                usb_err = ep1_generic_commandl(
                                                hdev_param, 3,
                                                EP1_CMD_DTC_CALL,
                                                buffer[0],
                                                EP1_CMD_DTC_WAIT
                                        );
                                if (usb_err < 0)
                                        return usb_err;

                                break;

                        case DTCLOAD_LUT_START:
                                lut_start = buffer[0];
                                break;

                        case DTCLOAD_LUT:
                                usb_err = ep1_memory_write(
                                                hdev_param,
                                                ST7_USB_BUF_EP0OUT + lut_start,
                                                header->length + 1, buffer
                                        );
                                if (usb_err < 0)
                                        return usb_err;
                                break;

                        default:
                                LOG_ERROR("Invalid DTC image record type: 0x%02x", header->type);
                                exit(1);
                                break;
                }

                buffer += (header->length + 1);
                length -= (header->length + 1);
        }

        return 0;
}

/*
 * Start the DTC running in download mode (waiting for 512 byte command packets on ep2).
 */
static int dtc_start_download(void)
{
        int usb_err;
        uint8_t ep2txr;
        int transferred;

        /* set up for download mode and make sure EP2 is set up to transmit */
        usb_err = ep1_generic_commandl(
                        hdev, 7,

                        EP1_CMD_DTC_STOP,
                        EP1_CMD_SET_UPLOAD,
                        EP1_CMD_SET_DOWNLOAD,
                        EP1_CMD_MEMORY_READ,    /* read EP2TXR for its data toggle */
                        ST7_EP2TXR >> 8,
                        ST7_EP2TXR,
                        1
                        );
        if (usb_err < 0)
                return usb_err;

        /* read back ep2txr */
        usb_err = jtag_libusb_bulk_read(
                        hdev, USB_EP1IN_ADDR,
                        (char *)&ep2txr, 1,
                        USB_TIMEOUT_MS,
                        &transferred
                        );
        if (usb_err != ERROR_OK)
                return usb_err;

        usb_err = ep1_generic_commandl(
                        hdev, 13,

                        EP1_CMD_MEMORY_WRITE,   /* preinitialize poll byte */
                        DTC_STATUS_POLL_BYTE >> 8,
                        DTC_STATUS_POLL_BYTE,
                        1,
                        0x00,
                        EP1_CMD_MEMORY_WRITE,   /* set EP2IN to return data */
                        ST7_EP2TXR >> 8,
                        ST7_EP2TXR,
                        1,
                        (ep2txr & ST7_EP2TXR_DTOG_TX) | ST7_EP2TXR_STAT_VALID,
                        EP1_CMD_DTC_CALL,       /* start running the DTC */
                        dtc_entry_download,
                        EP1_CMD_DTC_GET_CACHED_STATUS
                        );
        if (usb_err < 0)
                return usb_err;

        /* wait for completion */
        usb_err = jtag_libusb_bulk_read(
                        hdev, USB_EP1IN_ADDR,
                        (char *)&ep2txr, 1,
                        USB_TIMEOUT_MS,
                        &transferred
                        );

        return usb_err;
}

static int dtc_run_download(
        struct libusb_device_handle *hdev_param,
        uint8_t *command_buffer,
        int command_buffer_size,
        uint8_t *reply_buffer,
        int reply_buffer_size
        )
{
        char dtc_status;
        int usb_err;
        int i;
        int transferred;

        LOG_DEBUG("%d/%d", command_buffer_size, reply_buffer_size);

        usb_err = jtag_libusb_bulk_write(
                        hdev_param,
                        USB_EP2OUT_ADDR,
                        (char *)command_buffer, USB_EP2BANK_SIZE,
                        USB_TIMEOUT_MS,
                        &transferred
                        );
        if (usb_err < 0)
                return usb_err;


        /* Wait for DTC to finish running command buffer */
        for (i = 50;; ) {
                usb_err = ep1_generic_commandl(
                                hdev_param, 4,

                                EP1_CMD_MEMORY_READ,
                                DTC_STATUS_POLL_BYTE >> 8,
                                DTC_STATUS_POLL_BYTE,
                                1
                                );
                if (usb_err < 0)
                        return usb_err;

                usb_err = jtag_libusb_bulk_read(
                                hdev_param,
                                USB_EP1IN_ADDR,
                                &dtc_status, 1,
                                USB_TIMEOUT_MS,
                                &transferred
                                );
                if (usb_err < 0)
                        return usb_err;

                if (dtc_status & 0x01)
                        break;

                if (!--i) {
                        LOG_ERROR("too many retries waiting for DTC status");
                        return LIBUSB_ERROR_TIMEOUT;
                }
        }


        if (reply_buffer && reply_buffer_size) {
                usb_err = jtag_libusb_bulk_read(
                                hdev_param,
                                USB_EP2IN_ADDR,
                                (char *)reply_buffer, reply_buffer_size,
                                USB_TIMEOUT_MS,
                                &transferred
                                );

                if (usb_err != ERROR_OK || transferred < reply_buffer_size) {
                        LOG_ERROR("Read of endpoint 2 returned %d, expected %d",
                                usb_err, reply_buffer_size
                                );
                        return usb_err;
                }
        }

        return usb_err;
}

/*
 * The dtc reply queue is a singly linked list that describes what to do
 * with the reply packet that comes from the DTC.  Only SCAN_IN and SCAN_IO generate
 * these entries.
 */

struct dtc_reply_queue_entry {
        struct dtc_reply_queue_entry *next;
        struct jtag_command *cmd;       /* the command that resulted in this entry */

        struct {
                uint8_t *buffer;                /* the scan buffer */
                int size;                       /* size of the scan buffer in bits */
                int offset;                     /* how many bits were already done before this? */
                int length;                     /* how many bits are processed in this operation? */
                enum scan_type type;            /* SCAN_IN/SCAN_OUT/SCAN_IO */
        } scan;
};


/*
 * The dtc_queue consists of a buffer of pending commands and a reply queue.
 * rlink_scan and tap_state_run add to the command buffer and maybe to the reply queue.
 */

static struct {
        struct dtc_reply_queue_entry *rq_head;
        struct dtc_reply_queue_entry *rq_tail;
        uint32_t cmd_index;
        uint32_t reply_index;
        uint8_t cmd_buffer[USB_EP2BANK_SIZE];
} dtc_queue;

/*
 * The tap state queue is for accumulating TAP state changes without needlessly
 * flushing the dtc_queue.  When it fills or is run, it adds the accumulated bytes to
 * the dtc_queue.
 */

static struct {
        uint32_t length;
        uint32_t buffer;
} tap_state_queue;

static int dtc_queue_init(void)
{
        dtc_queue.rq_head = NULL;
        dtc_queue.rq_tail = NULL;
        dtc_queue.cmd_index = 0;
        dtc_queue.reply_index = 0;
        return 0;
}

static inline struct dtc_reply_queue_entry *dtc_queue_enqueue_reply(
        enum scan_type type, uint8_t *buffer, int size, int offset,
        int length, struct jtag_command *cmd)
{
        struct dtc_reply_queue_entry *rq_entry;

        rq_entry = malloc(sizeof(struct dtc_reply_queue_entry));
        if (rq_entry) {
                rq_entry->scan.type = type;
                rq_entry->scan.buffer = buffer;
                rq_entry->scan.size = size;
                rq_entry->scan.offset = offset;
                rq_entry->scan.length = length;
                rq_entry->cmd = cmd;
                rq_entry->next = NULL;

                if (!dtc_queue.rq_head)
                        dtc_queue.rq_head = rq_entry;
                else
                        dtc_queue.rq_tail->next = rq_entry;

                dtc_queue.rq_tail = rq_entry;
        }

        return rq_entry;
}

/*
 * Running the queue means that any pending command buffer is run
 * and any reply data dealt with.  The command buffer is then cleared for subsequent processing.
 * The queue is automatically run by append when it is necessary to get space for the append.
 */

static int dtc_queue_run(void)
{
        struct dtc_reply_queue_entry *rq_p, *rq_next;
        int retval;
        int usb_err;
        int bit_cnt;
        int x;
        uint8_t *dtc_p, *tdo_p;
        uint8_t dtc_mask, tdo_mask;
        uint8_t reply_buffer[USB_EP2IN_SIZE];

        assert((dtc_queue.rq_head != 0) == (dtc_queue.reply_index > 0));
        assert(dtc_queue.cmd_index < USB_EP2BANK_SIZE);
        assert(dtc_queue.reply_index <= USB_EP2IN_SIZE);

        retval = ERROR_OK;

        if (dtc_queue.cmd_index < 1)
                return retval;

        dtc_queue.cmd_buffer[dtc_queue.cmd_index++] = DTC_CMD_STOP;

        usb_err = dtc_run_download(hdev,
                        dtc_queue.cmd_buffer, dtc_queue.cmd_index,
                        reply_buffer, sizeof(reply_buffer)
                        );
        if (usb_err < 0) {
                LOG_ERROR("dtc_run_download: %s", libusb_error_name(usb_err));
                exit(1);
        }

        if (dtc_queue.rq_head) {
                /* process the reply, which empties the reply queue and frees its entries */
                dtc_p = reply_buffer;

                /* The rigamarole with the masks and doing it bit-by-bit is due to the fact that the
                 *scan buffer is LSb-first and the DTC code is MSb-first for hardware reasons.   It
                 *was that or craft a function to do the reversal, and that wouldn't work with
                 *bit-stuffing (supplying extra bits to use mostly byte operations), or any other
                 *scheme which would throw the byte alignment off. */

                for (
                        rq_p = dtc_queue.rq_head;
                        rq_p;
                        rq_p = rq_next
                        ) {
                        tdo_p = rq_p->scan.buffer + (rq_p->scan.offset / 8);
                        tdo_mask = 1 << (rq_p->scan.offset % 8);


                        bit_cnt = rq_p->scan.length;
                        if (bit_cnt >= 8) {
                                /* bytes */

                                dtc_mask = 1 << (8 - 1);

                                for (
                                        ;
                                        bit_cnt;
                                        bit_cnt--
                                        ) {
                                        if (*dtc_p & dtc_mask)
                                                *tdo_p |= tdo_mask;
                                        else
                                                *tdo_p &= ~tdo_mask;

                                        dtc_mask >>= 1;
                                        if (dtc_mask == 0) {
                                                dtc_p++;
                                                dtc_mask = 1 << (8 - 1);
                                        }

                                        tdo_mask <<= 1;
                                        if (tdo_mask == 0) {
                                                tdo_p++;
                                                tdo_mask = 1;
                                        }
                                }
                        } else {
                                /*  extra bits or last bit */

                                x = *dtc_p++;
                                if ((rq_p->scan.type == SCAN_IN) && (
                                                rq_p->scan.offset != rq_p->scan.size - 1
                                        )) {
                                        /* extra bits were sent as a full byte with padding on the
                                         *end */
                                        dtc_mask = 1 << (8 - 1);
                                } else
                                        dtc_mask = 1 << (bit_cnt - 1);

                                for (
                                        ;
                                        bit_cnt;
                                        bit_cnt--
                                        ) {
                                        if (x & dtc_mask)
                                                *tdo_p |= tdo_mask;
                                        else
                                                *tdo_p &= ~tdo_mask;

                                        dtc_mask >>= 1;

                                        tdo_mask <<= 1;
                                        if (tdo_mask == 0) {
                                                tdo_p++;
                                                tdo_mask = 1;
                                        }

                                }
                        }

                        if ((rq_p->scan.offset + rq_p->scan.length) >= rq_p->scan.size) {
                                /* feed scan buffer back into openocd and free it */
                                if (jtag_read_buffer(rq_p->scan.buffer,
                                                rq_p->cmd->cmd.scan) != ERROR_OK)
                                        retval = ERROR_JTAG_QUEUE_FAILED;
                                free(rq_p->scan.buffer);
                        }

                        rq_next = rq_p->next;
                        free(rq_p);
                }
                dtc_queue.rq_head = NULL;
                dtc_queue.rq_tail = NULL;
        }

        /* reset state for new appends */
        dtc_queue.cmd_index = 0;
        dtc_queue.reply_index = 0;

        return retval;
}

/* runs the queue if it cannot take reserved_cmd bytes of command data
 * or reserved_reply bytes of reply data */
static int dtc_queue_run_if_full(int reserved_cmd, int reserved_reply)
{
        /* reserve one additional byte for the STOP cmd appended during run */
        if (dtc_queue.cmd_index + reserved_cmd + 1 > USB_EP2BANK_SIZE)
                return dtc_queue_run();

        if (dtc_queue.reply_index + reserved_reply > USB_EP2IN_SIZE)
                return dtc_queue_run();

        return ERROR_OK;
}

static int tap_state_queue_init(void)
{
        tap_state_queue.length = 0;
        tap_state_queue.buffer = 0;
        return 0;
}

static int tap_state_queue_run(void)
{
        int i;
        int bits;
        uint8_t byte_param;
        int retval;

        retval = 0;
        if (!tap_state_queue.length)
                return retval;
        bits = 1;
        byte_param = 0;
        for (i = tap_state_queue.length; i--; ) {

                byte_param <<= 1;
                if (tap_state_queue.buffer & 1)
                        byte_param |= 1;
                if ((bits >= 8) || !i) {
                        byte_param <<= (8 - bits);

                        /* make sure there's room for two cmd bytes */
                        dtc_queue_run_if_full(2, 0);

#ifdef USE_HARDWARE_SHIFTER_FOR_TMS
                        if (bits == 8) {
                                dtc_queue.cmd_buffer[dtc_queue.cmd_index++] =
                                        DTC_CMD_SHIFT_TMS_BYTES(1);
                        } else {
#endif
                        dtc_queue.cmd_buffer[dtc_queue.cmd_index++] =
                                DTC_CMD_SHIFT_TMS_BITS(bits);
#ifdef USE_HARDWARE_SHIFTER_FOR_TMS
                }
#endif

                        dtc_queue.cmd_buffer[dtc_queue.cmd_index++] =
                                byte_param;

                        byte_param = 0;
                        bits = 1;
                } else
                        bits++;

                tap_state_queue.buffer >>= 1;
        }
        retval = tap_state_queue_init();
        return retval;
}

static int tap_state_queue_append(uint8_t tms)
{
        int retval;

        if (tap_state_queue.length >= sizeof(tap_state_queue.buffer) * 8) {
                retval = tap_state_queue_run();
                if (retval != 0)
                        return retval;
        }

        if (tms)
                tap_state_queue.buffer |= (1 << tap_state_queue.length);
        tap_state_queue.length++;

        return 0;
}

static void rlink_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 rlink_state_move(void)
{

        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 = 0; i < tms_count; i++) {
                tms = (tms_scan >> i) & 1;
                tap_state_queue_append(tms);
        }

        tap_set_state(tap_get_end_state());
}

static void rlink_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);
                }

                tap_state_queue_append(tms);

                tap_set_state(cmd->path[state_count]);
                state_count++;
                num_states--;
        }

        tap_set_end_state(tap_get_state());
}

static void rlink_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 RTI */
        if (tap_get_state() != TAP_IDLE) {
                rlink_end_state(TAP_IDLE);
                rlink_state_move();
        }

        /* execute num_cycles */
        for (i = 0; i < num_cycles; i++)
                tap_state_queue_append(0);

        /* finish in end_state */
        rlink_end_state(saved_end_state);
        if (tap_get_state() != tap_get_end_state())
                rlink_state_move();
}

/* (1) assert or (0) deassert reset lines */
static void rlink_reset(int trst, int srst)
{
        uint8_t bitmap;
        int usb_err;
        int transferred;

        /* Read port A for bit op */
        usb_err = ep1_generic_commandl(
                        hdev, 4,
                        EP1_CMD_MEMORY_READ,
                        ST7_PADR >> 8,
                        ST7_PADR,
                        1
                        );
        if (usb_err < 0) {
                LOG_ERROR("%s", libusb_error_name(usb_err));
                exit(1);
        }

        usb_err = jtag_libusb_bulk_read(
                        hdev, USB_EP1IN_ADDR,
                        (char *)&bitmap, 1,
                        USB_TIMEOUT_MS,
                        &transferred
                        );
        if (usb_err != ERROR_OK || transferred < 1) {
                LOG_ERROR("%s", libusb_error_name(usb_err));
                exit(1);
        }

        if (trst)
                bitmap &= ~ST7_PA_NTRST;
        else
                bitmap |= ST7_PA_NTRST;

        /* Write port A and read port B for bit op
         * port B has no OR, and we want to emulate open drain on NSRST, so we initialize DR to 0
         *and assert NSRST by setting DDR to 1. */
        usb_err = ep1_generic_commandl(
                        hdev, 9,
                        EP1_CMD_MEMORY_WRITE,
                        ST7_PADR >> 8,
                        ST7_PADR,
                        1,
                        bitmap,
                        EP1_CMD_MEMORY_READ,
                        ST7_PBDDR >> 8,
                        ST7_PBDDR,
                        1
                        );
        if (usb_err < 0) {
                LOG_ERROR("%s", libusb_error_name(usb_err));
                exit(1);
        }

        usb_err = jtag_libusb_bulk_read(
                        hdev, USB_EP1IN_ADDR,
                        (char *)&bitmap, 1,
                        USB_TIMEOUT_MS,
                        &transferred
                        );
        if (usb_err != ERROR_OK || transferred < 1) {
                LOG_ERROR("%s", libusb_error_name(usb_err));
                exit(1);
        }

        if (srst)
                bitmap |= ST7_PB_NSRST;
        else
                bitmap &= ~ST7_PB_NSRST;

        /* write port B and read dummy to ensure completion before returning */
        usb_err = ep1_generic_commandl(
                        hdev, 6,
                        EP1_CMD_MEMORY_WRITE,
                        ST7_PBDDR >> 8,
                        ST7_PBDDR,
                        1,
                        bitmap,
                        EP1_CMD_DTC_GET_CACHED_STATUS
                        );
        if (usb_err < 0) {
                LOG_ERROR("%s", libusb_error_name(usb_err));
                exit(1);
        }

        usb_err = jtag_libusb_bulk_read(
                        hdev, USB_EP1IN_ADDR,
                        (char *)&bitmap, 1,
                        USB_TIMEOUT_MS,
                        &transferred
                        );
        if (usb_err != ERROR_OK || transferred < 1) {
                LOG_ERROR("%s", libusb_error_name(usb_err));
                exit(1);
        }
}

static int rlink_scan(struct jtag_command *cmd, enum scan_type type,
                uint8_t *buffer, int scan_size)
{
        bool ir_scan;
        tap_state_t saved_end_state;
        int byte_bits;
        int extra_bits;
        int chunk_bits;
        int chunk_bytes;
        int x;

        int tdi_bit_offset;
        uint8_t tdi_mask, *tdi_p;
        uint8_t dtc_mask;

        if (scan_size < 1) {
                LOG_ERROR("scan_size cannot be less than 1 bit");
                exit(1);
        }

        ir_scan = cmd->cmd.scan->ir_scan;

        /* Move to the proper state before starting to shift TDI/TDO. */
        if (!((!ir_scan && (tap_get_state() == TAP_DRSHIFT)) ||
                        (ir_scan && (tap_get_state() == TAP_IRSHIFT)))) {
                saved_end_state = tap_get_end_state();
                rlink_end_state(ir_scan ? TAP_IRSHIFT : TAP_DRSHIFT);
                rlink_state_move();
                rlink_end_state(saved_end_state);
        }

        tap_state_queue_run();


#if 0
        printf("scan_size = %d, type = 0x%x\n", scan_size, type);
        {
                int i;

                /* clear unused bits in scan buffer for ease of debugging
                 * (it makes diffing output easier) */
                buffer[scan_size / 8] &= ((1 << ((scan_size - 1) % 8) + 1) - 1);

                printf("before scan:");
                for (i = 0; i < (scan_size + 7) / 8; i++)
                        printf(" %02x", buffer[i]);
                printf("\n");
        }
#endif

        /* The number of bits that can be shifted as complete bytes */
        byte_bits = (int)(scan_size - 1) / 8 * 8;
        /* The number of bits left over, not counting the last bit */
        extra_bits = (scan_size - 1) - byte_bits;

        tdi_bit_offset = 0;
        tdi_p = buffer;
        tdi_mask = 1;

        if (extra_bits && (type == SCAN_OUT)) {
                /* Schedule any extra bits into the DTC command buffer, padding as needed
                 * For SCAN_OUT, this comes before the full bytes so the (leading) padding bits will
                 *fall off the end */

                /* make sure there's room for two cmd bytes */
                dtc_queue_run_if_full(2, 0);

                x = 0;
                dtc_mask = 1 << (extra_bits - 1);

                while (extra_bits--) {
                        if (*tdi_p & tdi_mask)
                                x |= dtc_mask;

                        dtc_mask >>= 1;

                        tdi_mask <<= 1;
                        if (tdi_mask == 0) {
                                tdi_p++;
                                tdi_mask = 1;
                        }
                }

                dtc_queue.cmd_buffer[dtc_queue.cmd_index++] =
                        DTC_CMD_SHIFT_TDI_BYTES(1);

                dtc_queue.cmd_buffer[dtc_queue.cmd_index++] = x;
        }

        /* Loop scheduling full bytes into the DTC command buffer */
        while (byte_bits) {
                /* make sure there's room for one (for in scans) or two cmd bytes and
                 * at least one reply byte for in or inout scans*/
                dtc_queue_run_if_full(type == SCAN_IN ? 1 : 2, type != SCAN_OUT ? 1 : 0);

                chunk_bits = byte_bits;
                /* we can only use up to 16 bytes at a time */
                if (chunk_bits > (16 * 8))
                        chunk_bits = (16 * 8);

                if (type != SCAN_IN) {
                        /* how much is there room for, considering stop and byte op? */
                        x = (sizeof(dtc_queue.cmd_buffer) - (dtc_queue.cmd_index + 1 + 1)) * 8;
                        if (chunk_bits > x)
                                chunk_bits = x;
                }

                if (type != SCAN_OUT) {
                        /* how much is there room for in the reply buffer? */
                        x = (USB_EP2IN_SIZE - dtc_queue.reply_index) * 8;
                        if (chunk_bits > x)
                                chunk_bits = x;
                }

                /* so the loop will end */
                byte_bits -= chunk_bits;

                if (type != SCAN_OUT) {
                        if (!dtc_queue_enqueue_reply(type, buffer, scan_size, tdi_bit_offset,
                                        chunk_bits, cmd)) {
                                LOG_ERROR("enqueuing DTC reply entry: %s", strerror(errno));
                                exit(1);
                        }
                        dtc_queue.reply_index += (chunk_bits + 7) / 8;

                        tdi_bit_offset += chunk_bits;
                }

                /* chunk_bits is a multiple of 8, so there are no rounding issues. */
                chunk_bytes = chunk_bits / 8;

                switch (type) {
                        case SCAN_IN:
                                x = DTC_CMD_SHIFT_TDO_BYTES(chunk_bytes);
                                break;
                        case SCAN_OUT:
                                x = DTC_CMD_SHIFT_TDI_BYTES(chunk_bytes);
                                break;
                        default:
                                x = DTC_CMD_SHIFT_TDIO_BYTES(chunk_bytes);
                                break;
                }
                dtc_queue.cmd_buffer[dtc_queue.cmd_index++] = x;

                if (type != SCAN_IN) {
                        x = 0;
                        dtc_mask = 1 << (8 - 1);

                        while (chunk_bits--) {
                                if (*tdi_p & tdi_mask)
                                        x |= dtc_mask;

                                dtc_mask >>= 1;
                                if (dtc_mask == 0) {
                                        dtc_queue.cmd_buffer[dtc_queue.cmd_index++] = x;
                                        x = 0;
                                        dtc_mask = 1 << (8 - 1);
                                }

                                tdi_mask <<= 1;
                                if (tdi_mask == 0) {
                                        tdi_p++;
                                        tdi_mask = 1;
                                }
                        }
                }
        }

        if (extra_bits && (type != SCAN_OUT)) {
                /* Schedule any extra bits into the DTC command buffer */

                /* make sure there's room for one (for in scans) or two cmd bytes
                 * and one reply byte */
                dtc_queue_run_if_full(type == SCAN_IN ? 1 : 2, 1);

                if (!dtc_queue_enqueue_reply(type, buffer, scan_size, tdi_bit_offset,
                                extra_bits, cmd)) {
                        LOG_ERROR("enqueuing DTC reply entry: %s", strerror(errno));
                        exit(1);
                }

                dtc_queue.reply_index++;

                tdi_bit_offset += extra_bits;

                if (type == SCAN_IN) {
                        dtc_queue.cmd_buffer[dtc_queue.cmd_index++] =
                                DTC_CMD_SHIFT_TDO_BYTES(1);

                } else {
                        dtc_queue.cmd_buffer[dtc_queue.cmd_index++] =
                                DTC_CMD_SHIFT_TDIO_BITS(extra_bits);

                        x = 0;
                        dtc_mask = 1 << (8 - 1);

                        while (extra_bits--) {
                                if (*tdi_p & tdi_mask)
                                        x |= dtc_mask;

                                dtc_mask >>= 1;

                                tdi_mask <<= 1;
                                if (tdi_mask == 0) {
                                        tdi_p++;
                                        tdi_mask = 1;
                                }
                        }

                        dtc_queue.cmd_buffer[dtc_queue.cmd_index++] = x;
                }
        }

        /* Schedule the last bit into the DTC command buffer */

        /* make sure there's room for one cmd byte and one reply byte
         * for in or inout scans*/
        dtc_queue_run_if_full(1, type == SCAN_OUT ? 0 : 1);

        if (type == SCAN_OUT) {
                dtc_queue.cmd_buffer[dtc_queue.cmd_index++] =
                        DTC_CMD_SHIFT_TMS_TDI_BIT_PAIR(1, (*tdi_p & tdi_mask), 0);

        } else {
                if (!dtc_queue_enqueue_reply(type, buffer, scan_size, tdi_bit_offset,
                                1, cmd)) {
                        LOG_ERROR("enqueuing DTC reply entry: %s", strerror(errno));
                        exit(1);
                }

                dtc_queue.reply_index++;

                dtc_queue.cmd_buffer[dtc_queue.cmd_index++] =
                        DTC_CMD_SHIFT_TMS_TDI_BIT_PAIR(1, (*tdi_p & tdi_mask), 1);
        }

        /* Move to pause state */
        tap_state_queue_append(0);
        tap_set_state(ir_scan ? TAP_IRPAUSE : TAP_DRPAUSE);
        if (tap_get_state() != tap_get_end_state())
                rlink_state_move();

        return 0;
}

static int rlink_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, tmp_retval;

        /* return ERROR_OK, unless something goes wrong */
        retval = ERROR_OK;

#ifndef AUTOMATIC_BUSY_LED
        /* turn LED on */
        ep1_generic_commandl(hdev, 2,
                EP1_CMD_SET_PORTD_LEDS,
                ~(ST7_PD_NBUSY_LED)
                );
#endif

        while (cmd) {
                switch (cmd->type) {
                        case JTAG_RUNTEST:
                        case JTAG_TLR_RESET:
                        case JTAG_PATHMOVE:
                        case JTAG_SCAN:
                                break;

                        default:
                                /* some events, such as resets, need a queue flush to ensure
                                 *consistency */
                                tap_state_queue_run();
                                dtc_queue_run();
                                break;
                }

                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);
                                rlink_reset(cmd->cmd.reset->trst, cmd->cmd.reset->srst);
                                break;
                        case JTAG_RUNTEST:
                                LOG_DEBUG_IO("runtest %i cycles, end in %i",
                                                cmd->cmd.runtest->num_cycles,
                                                cmd->cmd.runtest->end_state);
                                if (cmd->cmd.runtest->end_state != -1)
                                        rlink_end_state(cmd->cmd.runtest->end_state);
                                rlink_runtest(cmd->cmd.runtest->num_cycles);
                                break;
                        case JTAG_TLR_RESET:
                                LOG_DEBUG_IO("statemove end in %i", cmd->cmd.statemove->end_state);
                                if (cmd->cmd.statemove->end_state != -1)
                                        rlink_end_state(cmd->cmd.statemove->end_state);
                                rlink_state_move();
                                break;
                        case JTAG_PATHMOVE:
                                LOG_DEBUG_IO("pathmove: %i states, end in %i",
                                                cmd->cmd.pathmove->num_states,
                                                cmd->cmd.pathmove->path[cmd->cmd.pathmove->num_states - 1]);
                                rlink_path_move(cmd->cmd.pathmove);
                                break;
                        case JTAG_SCAN:
                                LOG_DEBUG_IO("%s scan end in %i",
                                                (cmd->cmd.scan->ir_scan) ? "IR" : "DR",
                                                                cmd->cmd.scan->end_state);
                                if (cmd->cmd.scan->end_state != -1)
                                        rlink_end_state(cmd->cmd.scan->end_state);
                                scan_size = jtag_build_buffer(cmd->cmd.scan, &buffer);
                                type = jtag_scan_type(cmd->cmd.scan);
                                if (rlink_scan(cmd, type, buffer, scan_size) != ERROR_OK)
                                        retval = ERROR_FAIL;
                                break;
                        case JTAG_SLEEP:
                                LOG_DEBUG_IO("sleep %" PRIu32, cmd->cmd.sleep->us);
                                jtag_sleep(cmd->cmd.sleep->us);
                                break;
                        default:
                                LOG_ERROR("BUG: unknown JTAG command type encountered");
                                exit(-1);
                }
                cmd = cmd->next;
        }

        /* Flush the DTC queue to make sure any pending reads have been done before exiting this
         *function */
        tap_state_queue_run();
        tmp_retval = dtc_queue_run();
        if (tmp_retval != ERROR_OK)
                retval = tmp_retval;

#ifndef AUTOMATIC_BUSY_LED
        /* turn LED off */
        ep1_generic_commandl(hdev, 2,
                EP1_CMD_SET_PORTD_LEDS,
                ~0
                );
#endif

        return retval;
}

/* Using an unindexed table because it is infrequently accessed and it is short.  The table must be
 *in order of ascending speed (and descending prescaler), as it is scanned in reverse. */

static int rlink_speed(int speed)
{
        int i;

        if (speed == 0) {
                /* fastest speed */
                speed = rlink_speed_table[rlink_speed_table_size - 1].prescaler;
        }

        for (i = rlink_speed_table_size; i--; ) {
                if (rlink_speed_table[i].prescaler == speed) {
                        if (dtc_load_from_buffer(hdev, rlink_speed_table[i].dtc,
                                        rlink_speed_table[i].dtc_size) != 0) {
                                LOG_ERROR(
                                        "An error occurred while trying to load DTC code for speed \"%d\".",
                                        speed);
                                exit(1);
                        }

                        int ret = dtc_start_download();
                        if (ret < 0) {
                                LOG_ERROR("starting DTC: %s", libusb_error_name(ret));
                                exit(1);
                        }

                        return ERROR_OK;
                }
        }

        LOG_ERROR("%d is not a supported speed", speed);
        return ERROR_FAIL;
}

static int rlink_speed_div(int speed, int *khz)
{
        int i;

        for (i = rlink_speed_table_size; i--; ) {
                if (rlink_speed_table[i].prescaler == speed) {
                        *khz = rlink_speed_table[i].khz;
                        return ERROR_OK;
                }
        }

        LOG_ERROR("%d is not a supported speed", speed);
        return ERROR_FAIL;
}

static int rlink_khz(int khz, int *speed)
{
        int i;

        if (khz == 0) {
                LOG_ERROR("RCLK not supported");
                return ERROR_FAIL;
        }

        for (i = rlink_speed_table_size; i--; ) {
                if (rlink_speed_table[i].khz <= khz) {
                        *speed = rlink_speed_table[i].prescaler;
                        return ERROR_OK;
                }
        }

        LOG_WARNING("The lowest supported JTAG speed is %d KHz", rlink_speed_table[0].khz);
        *speed = rlink_speed_table[0].prescaler;
        return ERROR_OK;
}

static int rlink_init(void)
{
        int i, j, retries;
        uint8_t reply_buffer[USB_EP1IN_SIZE];
        int transferred;

        const uint16_t vids[] = { USB_IDVENDOR, 0 };
        const uint16_t pids[] = { USB_IDPRODUCT, 0 };
        if (jtag_libusb_open(vids, pids, NULL, &hdev, NULL) != ERROR_OK)
                return ERROR_FAIL;

        struct libusb_device_descriptor descriptor;
        struct libusb_device *usb_dev = libusb_get_device(hdev);
        int r = libusb_get_device_descriptor(usb_dev, &descriptor);
        if (r < 0) {
                LOG_ERROR("error %d getting device descriptor", r);
                return ERROR_FAIL;
        }

        if (descriptor.bNumConfigurations > 1) {
                LOG_ERROR("Whoops! NumConfigurations is not 1, don't know what to do...");
                return ERROR_FAIL;
        }
        struct libusb_config_descriptor *config;
        libusb_get_config_descriptor(usb_dev, 0, &config);
        if (config->bNumInterfaces > 1) {
                LOG_ERROR("Whoops! NumInterfaces is not 1, don't know what to do...");
                return ERROR_FAIL;
        }

        LOG_DEBUG("Opened device, hdev = %p", hdev);

        /* usb_set_configuration required under win32 */
        libusb_set_configuration(hdev, config->bConfigurationValue);

        retries = 3;
        do {
                i = libusb_claim_interface(hdev, 0);
                if (i != LIBUSB_SUCCESS) {
                        LOG_ERROR("usb_claim_interface: %s", libusb_error_name(i));
                        j = libusb_detach_kernel_driver(hdev, 0);
                        if (j != LIBUSB_SUCCESS)
                                LOG_ERROR("detach kernel driver: %s", libusb_error_name(j));
                } else {
                        LOG_DEBUG("interface claimed!");
                        break;
                }
        } while (--retries);

        if (i != LIBUSB_SUCCESS) {
                LOG_ERROR("Initialisation failed.");
                return ERROR_FAIL;
        }
        if (libusb_set_interface_alt_setting(hdev, 0, 0) != LIBUSB_SUCCESS) {
                LOG_ERROR("Failed to set interface.");
                return ERROR_FAIL;
        }

        /* The device starts out in an unknown state on open.  As such,
         * result reads time out, and it's not even known whether the
         * command was accepted.  So, for this first command, we issue
         * it repeatedly until its response doesn't time out.  Also, if
         * sending a command is going to time out, we find that out here.
         *
         * It must be possible to open the device in such a way that
         * this special magic isn't needed, but, so far, it escapes us.
         */
        for (i = 0; i < 5; i++) {
                j = ep1_generic_commandl(
                                hdev, 1,
                                EP1_CMD_GET_FWREV
                                );
                if (j < USB_EP1OUT_SIZE) {
                        LOG_ERROR("USB write error: %s", libusb_error_name(j));
                        return ERROR_FAIL;
                }
                j = jtag_libusb_bulk_read(
                                hdev, USB_EP1IN_ADDR,
                                (char *)reply_buffer, sizeof(reply_buffer),
                                200,
                                &transferred
                                );
                if (j != LIBUSB_ERROR_TIMEOUT)
                        break;
        }

        if (j != ERROR_OK || transferred != (int)sizeof(reply_buffer)) {
                LOG_ERROR("USB read error: %s", libusb_error_name(j));
                return ERROR_FAIL;
        }
        LOG_DEBUG(INTERFACE_NAME " firmware version: %d.%d.%d",
                reply_buffer[0],
                reply_buffer[1],
                reply_buffer[2]);

        if ((reply_buffer[0] != 0) || (reply_buffer[1] != 0) || (reply_buffer[2] != 3))
                LOG_WARNING(
                        "The rlink device is not of the version that the developers have played with.  It may or may not work.");

        /* Probe port E for adapter presence */
        ep1_generic_commandl(
                hdev, 16,
                EP1_CMD_MEMORY_WRITE,           /* Drive sense pin with 0 */
                ST7_PEDR >> 8,
                ST7_PEDR,
                3,
                0x00,                                                   /* DR */
                ST7_PE_ADAPTER_SENSE_OUT,               /* DDR */
                ST7_PE_ADAPTER_SENSE_OUT,               /* OR */
                EP1_CMD_MEMORY_READ,            /* Read back */
                ST7_PEDR >> 8,
                ST7_PEDR,
                1,
                EP1_CMD_MEMORY_WRITE,           /* Drive sense pin with 1 */
                ST7_PEDR >> 8,
                ST7_PEDR,
                1,
                ST7_PE_ADAPTER_SENSE_OUT
                );

        jtag_libusb_bulk_read(
                hdev, USB_EP1IN_ADDR,
                (char *)reply_buffer, 1,
                USB_TIMEOUT_MS,
                &transferred
                );

        if ((reply_buffer[0] & ST7_PE_ADAPTER_SENSE_IN) != 0)
                LOG_WARNING("target detection problem");

        ep1_generic_commandl(
                hdev, 11,
                EP1_CMD_MEMORY_READ,            /* Read back */
                ST7_PEDR >> 8,
                ST7_PEDR,
                1,
                EP1_CMD_MEMORY_WRITE,           /* float port E */
                ST7_PEDR >> 8,
                ST7_PEDR,
                3,
                0x00,           /* DR */
                0x00,           /* DDR */
                0x00            /* OR */
                );

        jtag_libusb_bulk_read(
                hdev, USB_EP1IN_ADDR,
                (char *)reply_buffer, 1,
                USB_TIMEOUT_MS,
                &transferred
                );


        if ((reply_buffer[0] & ST7_PE_ADAPTER_SENSE_IN) == 0)
                LOG_WARNING("target not plugged in");

        /* float ports A and B */
        ep1_generic_commandl(
                hdev, 11,
                EP1_CMD_MEMORY_WRITE,
                ST7_PADDR >> 8,
                ST7_PADDR,
                2,
                0x00,
                0x00,
                EP1_CMD_MEMORY_WRITE,
                ST7_PBDDR >> 8,
                ST7_PBDDR,
                1,
                0x00
                );

        /* make sure DTC is stopped, set VPP control, set up ports A and B */
        ep1_generic_commandl(
                hdev, 14,
                EP1_CMD_DTC_STOP,
                EP1_CMD_SET_PORTD_VPP,
                ~(ST7_PD_VPP_SHDN),
                EP1_CMD_MEMORY_WRITE,
                ST7_PADR >> 8,
                ST7_PADR,
                2,
                ((~(0)) & (ST7_PA_NTRST)),
                (ST7_PA_NTRST),
                /* port B has no OR, and we want to emulate open drain on NSRST, so we set DR to 0
                 *here and later assert NSRST by setting DDR bit to 1. */
                EP1_CMD_MEMORY_WRITE,
                ST7_PBDR >> 8,
                ST7_PBDR,
                1,
                0x00
                );

        /* set LED updating mode and make sure they're unlit */
        ep1_generic_commandl(
                hdev, 3,
#ifdef AUTOMATIC_BUSY_LED
                EP1_CMD_LEDUE_BUSY,
#else
                EP1_CMD_LEDUE_NONE,
#endif
                EP1_CMD_SET_PORTD_LEDS,
                ~0
                );

        tap_state_queue_init();
        dtc_queue_init();
        rlink_reset(0, 0);

        return ERROR_OK;
}

static int rlink_quit(void)
{
        /* stop DTC and make sure LEDs are off */
        ep1_generic_commandl(
                hdev, 6,
                EP1_CMD_DTC_STOP,
                EP1_CMD_LEDUE_NONE,
                EP1_CMD_SET_PORTD_LEDS,
                ~0,
                EP1_CMD_SET_PORTD_VPP,
                ~0
                );

        libusb_release_interface(hdev, 0);
        libusb_close(hdev);

        return ERROR_OK;
}

static struct jtag_interface rlink_interface = {
        .execute_queue = rlink_execute_queue,
};

struct adapter_driver rlink_adapter_driver = {
        .name = "rlink",
        .transports = jtag_only,

        .init = rlink_init,
        .quit = rlink_quit,
        .speed = rlink_speed,
        .khz = rlink_khz,
        .speed_div = rlink_speed_div,

        .jtag_ops = &rlink_interface,
};