rlink: simplify and optimize queue fill level checks

[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, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

/* project specific includes */
#include <jtag/interface.h>
#include <jtag/commands.h>
#include "rlink.h"
#include "rlink_st7.h"
#include "rlink_ep1_cmd.h"
#include "rlink_dtc_cmd.h"
#include "usb_common.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 usb_dev_handle *pHDev;


/*
 * 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(
                usb_dev_handle  *pHDev_param,
                size_t          length,
                ...
) {
        uint8_t         usb_buffer[USB_EP1OUT_SIZE];
        uint8_t         *usb_buffer_p;
        va_list         ap;
        int             usb_ret;

        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 = usb_bulk_write(
                        pHDev_param,
                        USB_EP1OUT_ADDR,
                        (char *)usb_buffer, sizeof(usb_buffer),
                        USB_TIMEOUT_MS
        );

        return(usb_ret);
}



#if 0
static
ssize_t
ep1_memory_read(
                usb_dev_handle  *pHDev,
                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;

        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 = usb_bulk_write(
                                pHDev, USB_EP1OUT_ADDR,
                                usb_buffer, sizeof(usb_buffer),
                                USB_TIMEOUT_MS
                );

                if (usb_ret < sizeof(usb_buffer)) {
                        break;
                }

                usb_ret = usb_bulk_read(
                                pHDev, USB_EP1IN_ADDR,
                                buffer, length,
                                USB_TIMEOUT_MS
                );

                if (usb_ret < length) {
                        break;
                }

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

        return(count);
}
#endif



static
ssize_t
ep1_memory_write(
                usb_dev_handle  *pHDev_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
                );

                usb_ret = usb_bulk_write(
                                pHDev_param, USB_EP1OUT_ADDR,
                                (char *)usb_buffer, sizeof(usb_buffer),
                                USB_TIMEOUT_MS
                );

                if ((size_t)usb_ret < sizeof(usb_buffer)) {
                        break;
                }

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

        return(count);
}


#if 0
static
ssize_t
ep1_memory_writel(
                usb_dev_handle  *pHDev,
                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(pHDev, 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(
                usb_dev_handle  *pHDev_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(
                        pHDev_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(
                                        pHDev_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(
                                        pHDev_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(
                                        pHDev_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(
                                        pHDev_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;

        /* set up for download mode and make sure EP2 is set up to transmit */
        usb_err = ep1_generic_commandl(
                        pHDev, 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 = usb_bulk_read(
                        pHDev, USB_EP1IN_ADDR,
                        (char *)&ep2txr, 1,
                        USB_TIMEOUT_MS
        );
        if (usb_err < 0) return(usb_err);

        usb_err = ep1_generic_commandl(
                        pHDev, 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 = usb_bulk_read(
                        pHDev, USB_EP1IN_ADDR,
                        (char *)&ep2txr, 1,
                        USB_TIMEOUT_MS
        );

        return(usb_err);
}


static
int
dtc_run_download(
                usb_dev_handle  *pHDev_param,
                uint8_t *command_buffer,
                int     command_buffer_size,
                uint8_t *reply_buffer,
                int     reply_buffer_size
) {
        uint8_t ep2_buffer[USB_EP2IN_SIZE];
        int     usb_err;
        int     i;

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

        usb_err = usb_bulk_write(
                        pHDev_param,
                        USB_EP2OUT_ADDR,
                        (char *)command_buffer, USB_EP2BANK_SIZE,
                        USB_TIMEOUT_MS
        );
        if (usb_err < 0) return(usb_err);


        /* Wait for DTC to finish running command buffer */
        for (i = 10;;) {
                usb_err = ep1_generic_commandl(
                                pHDev_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 = usb_bulk_read(
                                pHDev_param,
                                USB_EP1IN_ADDR,
                                (char *)ep2_buffer, 1,
                                USB_TIMEOUT_MS
                );
                if (usb_err < 0) return(usb_err);

                if (ep2_buffer[0] & 0x01) break;

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


        if (!reply_buffer) reply_buffer_size = 0;
        if (reply_buffer_size) {
                usb_err = usb_bulk_read(
                                pHDev_param,
                                USB_EP2IN_ADDR,
                                (char *)ep2_buffer, sizeof(ep2_buffer),
                                USB_TIMEOUT_MS
                );

                if (usb_err < (int)sizeof(ep2_buffer)) {
                        LOG_ERROR("Read of endpoint 2 returned %d, expected %d",
                                        usb_err, reply_buffer_size
                        );
                        return(usb_err);
                }

                memcpy(reply_buffer, ep2_buffer, reply_buffer_size);

        }

        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 wiithout 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 != NULL) {
                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 == NULL)
                        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(pHDev,
                        dtc_queue.cmd_buffer, dtc_queue.cmd_index,
                        reply_buffer, dtc_queue.reply_index
        );
        if (usb_err < 0) {
                LOG_ERROR("dtc_run_download: %s", usb_strerror());
                exit(1);
        }

        if (dtc_queue.rq_head != NULL) {
                /* 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 != NULL;
                                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;

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

        usb_err = usb_bulk_read(
                        pHDev, USB_EP1IN_ADDR,
                        (char *)&bitmap, 1,
                        USB_TIMEOUT_MS
        );
        if (usb_err < 1) {
                LOG_ERROR("%s", usb_strerror());
                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(
                        pHDev, 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", usb_strerror());
                exit(1);
        }

        usb_err = usb_bulk_read(
                        pHDev, USB_EP1IN_ADDR,
                        (char *)&bitmap, 1,
                        USB_TIMEOUT_MS
        );
        if (usb_err < 1) {
                LOG_ERROR("%s", usb_strerror());
                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(
                        pHDev, 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", usb_strerror());
                exit(1);
        }

        usb_err = usb_bulk_read(
                        pHDev, USB_EP1IN_ADDR,
                        (char *)&bitmap, 1,
                        USB_TIMEOUT_MS
        );
        if (usb_err < 1) {
                LOG_ERROR("%s", usb_strerror());
                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
                        ) == NULL) {
                                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
                ) == NULL) {
                        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
                ) == NULL) {
                        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(pHDev, 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:
#ifdef _DEBUG_JTAG_IO_
                        LOG_DEBUG("reset trst: %i srst %i", cmd->cmd.reset->trst, cmd->cmd.reset->srst);
#endif
                        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:
#ifdef _DEBUG_JTAG_IO_
                        LOG_DEBUG("runtest %i cycles, end in %i", cmd->cmd.runtest->num_cycles, cmd->cmd.runtest->end_state);
#endif
                        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:
#ifdef _DEBUG_JTAG_IO_
                        LOG_DEBUG("statemove end in %i", cmd->cmd.statemove->end_state);
#endif
                        if (cmd->cmd.statemove->end_state != -1)
                                rlink_end_state(cmd->cmd.statemove->end_state);
                        rlink_state_move();
                        break;
                case JTAG_PATHMOVE:
#ifdef _DEBUG_JTAG_IO_
                        LOG_DEBUG("pathmove: %i states, end in %i", cmd->cmd.pathmove->num_states, cmd->cmd.pathmove->path[cmd->cmd.pathmove->num_states - 1]);
#endif
                        rlink_path_move(cmd->cmd.pathmove);
                        break;
                case JTAG_SCAN:
#ifdef _DEBUG_JTAG_IO_
                        LOG_DEBUG("%s scan end in %i",  (cmd->cmd.scan->ir_scan) ? "IR" : "DR", cmd->cmd.scan->end_state);
#endif
                        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:
#ifdef _DEBUG_JTAG_IO_
                        LOG_DEBUG("sleep %i", cmd->cmd.sleep->us);
#endif
                        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 onff */
        ep1_generic_commandl(pHDev, 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(pHDev, 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);
                        }

                        if (dtc_start_download() < 0) {
                                LOG_ERROR("starting DTC: %s", usb_strerror());
                                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];

        usb_init();
        const uint16_t vids[] = { USB_IDVENDOR, 0 };
        const uint16_t pids[] = { USB_IDPRODUCT, 0 };
        if (jtag_usb_open(vids, pids, &pHDev) != ERROR_OK)
                return ERROR_FAIL;

        struct usb_device *dev = usb_device(pHDev);
        if (dev->descriptor.bNumConfigurations > 1)
        {
                LOG_ERROR("Whoops! NumConfigurations is not 1, don't know what to do...");
                return ERROR_FAIL;
        }
        if (dev->config->bNumInterfaces > 1)
        {
                LOG_ERROR("Whoops! NumInterfaces is not 1, don't know what to do...");
                return ERROR_FAIL;
        }

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

        /* usb_set_configuration required under win32 */
        usb_set_configuration(pHDev, dev->config[0].bConfigurationValue);

        retries = 3;
        do
        {
                i = usb_claim_interface(pHDev,0);
                if (i)
                {
                        LOG_ERROR("usb_claim_interface: %s", usb_strerror());
#ifdef LIBUSB_HAS_DETACH_KERNEL_DRIVER_NP
                        j = usb_detach_kernel_driver_np(pHDev, 0);
                        if (j)
                                LOG_ERROR("detach kernel driver: %s", usb_strerror());
#endif
                }
                else
                {
                        LOG_DEBUG("interface claimed!");
                        break;
                }
        } while (--retries);

        if (i)
        {
                LOG_ERROR("Initialisation failed.");
                return ERROR_FAIL;
        }
        if (usb_set_altinterface(pHDev,0) != 0)
        {
                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(
                                pHDev, 1,
                                EP1_CMD_GET_FWREV
                );
                if (j < USB_EP1OUT_SIZE) {
                        LOG_ERROR("USB write error: %s", usb_strerror());
                        return(ERROR_FAIL);
                }
                j = usb_bulk_read(
                                pHDev, USB_EP1IN_ADDR,
                                (char *)reply_buffer, sizeof(reply_buffer),
                                200
                );
                if (j != -ETIMEDOUT) break;
        }

        if (j < (int)sizeof(reply_buffer)) {
                LOG_ERROR("USB read error: %s", usb_strerror());
                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(
                        pHDev, 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
        );

        usb_bulk_read(
                        pHDev, USB_EP1IN_ADDR,
                        (char *)reply_buffer, 1,
                        USB_TIMEOUT_MS
        );

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

        ep1_generic_commandl(
                        pHDev, 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 */
        );

        usb_bulk_read(
                        pHDev, USB_EP1IN_ADDR,
                        (char *)reply_buffer, 1,
                        USB_TIMEOUT_MS
        );


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

        /* float ports A and B */
        ep1_generic_commandl(
                        pHDev, 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(
                        pHDev, 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(
                        pHDev, 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(
                        pHDev, 6,
                        EP1_CMD_DTC_STOP,
                        EP1_CMD_LEDUE_NONE,
                        EP1_CMD_SET_PORTD_LEDS,
                        ~0,
                        EP1_CMD_SET_PORTD_VPP,
                        ~0
        );

        usb_release_interface(pHDev,0);
        usb_close(pHDev);


        return ERROR_OK;
}


struct jtag_interface rlink_interface =
{
                .name = "rlink",
                .init = rlink_init,
                .quit = rlink_quit,
                .speed = rlink_speed,
                .speed_div = rlink_speed_div,
                .khz = rlink_khz,
                .execute_queue = rlink_execute_queue,
};