From Lou.openocd012@fixit.nospammail.net

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

/* system includes */
#include <errno.h>
#include <string.h>
#include <usb.h>
#include <stdint.h>

/* project specific includes */
#include "log.h"
#include "types.h"
#include "jtag.h"
#include "configuration.h"
#include "rlink.h"
#include "st7.h"
#include "ep1_cmd.h"
#include "dtc_cmd.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)


/* Symbolic names for some pins */
#define ST7_PA_NJTAG_TRST               ST7_PA1
#define ST7_PA_NRLINK_RST               ST7_PA3
#define ST7_PA_NLINE_DRIVER_ENABLE      ST7_PA5

/* mask for negative-logic pins */
#define ST7_PA_NUNASSERTED      (0      \
        | ST7_PA_NJTAG_TRST     \
        | ST7_PA_NRLINK_RST     \
        | ST7_PA_NLINE_DRIVER_ENABLE    \
)

#define ST7_PD_NBUSY_LED                ST7_PD0
#define ST7_PD_NERROR_LED               ST7_PD1
#define ST7_PD_NRUN_LED                 ST7_PD7

#define ST7_PE_ADAPTER_SENSE_IN         ST7_PE3
#define ST7_PE_ADAPTER_SENSE_OUT        ST7_PE4

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,
        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,
                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,
        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, USB_EP1OUT_ADDR,
                        (char *)usb_buffer, sizeof(usb_buffer),
                        USB_TIMEOUT_MS
                );

                if(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,
        const u8                *buffer,
        size_t                  length
) {
        struct header_s {
                u8      type;
                u8      length;
        };

        int                             usb_err;
        struct header_s *header;
        u8                              lut_start = 0xc0;

        dtc_entry_download = 0;

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

        while(length) {
                if(length < sizeof(*header)) {
                        LOG_ERROR("Malformed DTC image\n");
                        exit(1);
                }
                
                header = (struct header_s *)buffer;
                buffer += sizeof(*header);
                length -= sizeof(*header);

                if(length < header->length + 1) {
                        LOG_ERROR("Malformed DTC image\n");
                        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,
                                        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, 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, 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,
                                        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\n", 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(
) {
        int     usb_err;
        u8      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,
        u8      *command_buffer,
        int     command_buffer_size,
        u8      *reply_buffer,
        int     reply_buffer_size
) {
        u8      ep2_buffer[USB_EP2IN_SIZE];
        int     usb_err;
        int     i;

        LOG_DEBUG(": %d/%d\n", command_buffer_size, reply_buffer_size);

        usb_err = usb_bulk_write(
                pHDev,
                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 = 5;;) {
                usb_err = ep1_generic_commandl(
                        pHDev, 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,
                        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("%s, %d: too many retries waiting for DTC status\n",
                                __FILE__, __LINE__
                        );
                        return(-ETIMEDOUT);
                }
        }


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

                if(usb_err < (int)sizeof(ep2_buffer)) {
                        LOG_ERROR("%s, %d: Read of endpoint 2 returned %d\n",
                                __FILE__, __LINE__, usb_err
                        );
                        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.
 */

typedef
struct dtc_reply_queue_entry_s {
        struct dtc_reply_queue_entry_s  *next;
        jtag_command_t  *cmd;   /* the command that resulted in this entry */

        struct {
                u8              *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;
} dtc_reply_queue_entry_t;


/*
 * 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 {
        dtc_reply_queue_entry_t *rq_head;
        dtc_reply_queue_entry_t *rq_tail;
        int                     cmd_index;
        int                     reply_index;
        u8                      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 {
        int     length;
        u32     buffer;
} tap_state_queue;



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


static
inline
dtc_reply_queue_entry_t *
dtc_queue_enqueue_reply(
        enum scan_type  type,
        u8                              *buffer,
        int                             size,
        int                             offset,
        int                             length,
        jtag_command_t  *cmd
) {
        dtc_reply_queue_entry_t *rq_entry;

        rq_entry = malloc(sizeof(dtc_reply_queue_entry_t));
        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(
) {
        dtc_reply_queue_entry_t *rq_p, *rq_next;
        int                     retval;
        int                     usb_err;
        int                     bit_cnt;
        int                     x;
        u8                      *dtc_p, *tdo_p;
        u8                      dtc_mask, tdo_mask;
        u8                      reply_buffer[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;

        /* run the cmd */
        if(dtc_queue.rq_head == NULL) {
                usb_err = dtc_run_download(pHDev,
                        dtc_queue.cmd_buffer, dtc_queue.cmd_index,
                        NULL, 0
                );      
                if(usb_err < 0) {
                        LOG_ERROR("dtc_run_download: %s\n", usb_strerror());
                        exit(1);
                }
        } else {
                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\n", usb_strerror());
                        exit(1);
                } else {
                        /* 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);
}



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


static
int
tap_state_queue_run(
) {
        int     i;
        int     bits;
        u8      byte;
        int     retval;

        retval = 0;
        if(!tap_state_queue.length) return(retval);
        bits = 1;
        byte = 0;
        for(i = tap_state_queue.length; i--;) {
                
                byte <<= 1;
                if(tap_state_queue.buffer & 1) {
                        byte |= 1;
                }
                if((bits >= 8) || !i) {
                        byte <<= (8 - bits);

                        /* make sure there's room for stop, byte op, and one byte */
                        if(dtc_queue.cmd_index >= (sizeof(dtc_queue.cmd_buffer) - (1 + 1 + 1))) {
                                dtc_queue.cmd_buffer[dtc_queue.cmd_index++] =
                                        DTC_CMD_STOP;
                                dtc_queue_run();
                        }

#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;

                        byte = 0;
                        bits = 1;
                } else {
                        bits++;
                }

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


static
int
tap_state_queue_append(
        u8      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(enum tap_state state)
{
        if (tap_move_map[state] != -1)
                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;
        u8 tms_scan = TAP_MOVE(cur_state, end_state);

        for (i = 0; i < 7; i++)
        {
                tms = (tms_scan >> i) & 1;
                tap_state_queue_append(tms);
        }

        cur_state = end_state;
}

static
void rlink_path_move(pathmove_command_t *cmd)
{
        int num_states = cmd->num_states;
        int state_count;
        int tms = 0;

        state_count = 0;
        while (num_states)
        {
                if (tap_transitions[cur_state].low == cmd->path[state_count])
                {
                        tms = 0;
                }
                else if (tap_transitions[cur_state].high == cmd->path[state_count])
                {
                        tms = 1;
                }
                else
                {
                        LOG_ERROR("BUG: %s -> %s isn't a valid TAP transition", jtag_state_name(cur_state), jtag_state_name(cmd->path[state_count]));
                        exit(-1);
                }

                tap_state_queue_append(tms);

                cur_state = cmd->path[state_count];
                state_count++;
                num_states--;
        }

        end_state = cur_state;
}


static
void rlink_runtest(int num_cycles)
{
        int i;

        enum tap_state saved_end_state = end_state;

        /* only do a state_move when we're not already in RTI */
        if (cur_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 (cur_state != end_state)
                rlink_state_move();
}


/* (1) assert or (0) deassert reset lines */
static
void rlink_reset(int trst, int srst)
{
        u8                      bitmap;
        int                     usb_err;

        bitmap = ((~(ST7_PA_NLINE_DRIVER_ENABLE)) & ST7_PA_NUNASSERTED);

        if(trst) {
                bitmap &= ~ST7_PA_NJTAG_TRST;
        }
        if(srst) {
                bitmap &= ~ST7_PA_NRLINK_RST;
        }

        usb_err = ep1_generic_commandl(
                pHDev, 6,
                 
                EP1_CMD_MEMORY_WRITE,
                        ST7_PADR >> 8,
                        ST7_PADR,
                        1,
                        bitmap,
                EP1_CMD_DTC_GET_CACHED_STATUS
        );
        if(usb_err < 0) {
                LOG_ERROR("%s: %s\n", __func__, usb_strerror());
                exit(1);
        }

        usb_err = usb_bulk_read(
                pHDev, USB_EP1IN_ADDR,
                &bitmap, 1,
                USB_TIMEOUT_MS
        );
        if(usb_err < 1) {
                LOG_ERROR("%s: %s\n", __func__, usb_strerror());
                exit(1);
        }
}


static
int
rlink_scan(
        jtag_command_t  *cmd,
        enum scan_type  type,
        u8                      *buffer,
        int                     scan_size
) {
        int                     ir_scan;
        enum tap_state  saved_end_state;
        int                     byte_bits;
        int                     extra_bits;
        int                     chunk_bits;
        int                     chunk_bytes;
        int                     x;

        int                     tdi_bit_offset;
        u8                      tdi_mask, *tdi_p;
        u8                      dtc_mask;

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

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

        /* Move to the proper state before starting to shift TDI/TDO. */
        if (!(
                (!ir_scan && (cur_state == TAP_DRSHIFT))
                ||
                (ir_scan && (cur_state == TAP_IRSHIFT))
        )) {
                saved_end_state = 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 stop, byte op, and one byte */
                if(
                        (dtc_queue.cmd_index >= sizeof(dtc_queue.cmd_buffer) - (1 + 1 + 1))
                ) {
                        dtc_queue_run();
                }

                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) {
                if(type == SCAN_IN) {
                        /* make sure there's room for stop and byte op */
                        x = (dtc_queue.cmd_index >= sizeof(dtc_queue.cmd_buffer) - (1 + 1));
                } else {
                        /* make sure there's room for stop, byte op, and at least one byte */
                        x = (dtc_queue.cmd_index >= sizeof(dtc_queue.cmd_buffer) - (1 + 1 + 1));
                }

                if(type != SCAN_OUT) {
                        /* make sure there's room for at least one reply byte */
                        x |= (dtc_queue.reply_index >= USB_EP2IN_SIZE - (1));
                }

                if(x) {
                        dtc_queue_run();
                }

                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\n", strerror(errno));
                                exit(1);
                        }
                        
                        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;
                                        dtc_queue.reply_index++;
                                        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 stop, byte op, and one byte */
                if(
                        (dtc_queue.cmd_index >= sizeof(dtc_queue.cmd_buffer) - (1 + 1 + 1))
                        ||
                        (dtc_queue.reply_index >= USB_EP2IN_SIZE - (1))
                ) {
                        dtc_queue_run();
                }

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

                dtc_queue.reply_index++;
        }

        /* Schedule the last bit into the DTC command buffer */
        {
                /* make sure there's room for stop, and bit pair command */
                if(
                        (dtc_queue.cmd_index >= sizeof(dtc_queue.cmd_buffer) - (1 + 1))
                        ||
                        (dtc_queue.reply_index >= USB_EP2IN_SIZE - (1))
                ) {
                        dtc_queue_run();
                }

                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\n", strerror(errno));
                                exit(1);
                        }
                        
                        dtc_queue.cmd_buffer[dtc_queue.cmd_index++] = 
                                DTC_CMD_SHIFT_TMS_TDI_BIT_PAIR(1, (*tdi_p & tdi_mask), 1);

                        dtc_queue.reply_index++;
                }
        }

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

        return(0);
}


static
int rlink_execute_queue(void)
{
        jtag_command_t *cmd = jtag_command_queue; /* currently processed command */
        int scan_size;
        enum scan_type type;
        u8 *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_END_STATE:
                        case JTAG_RUNTEST:
                        case JTAG_STATEMOVE:
                        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_END_STATE:
#ifdef _DEBUG_JTAG_IO_
                                LOG_DEBUG("end_state: %i", cmd->cmd.end_state->end_state);
#endif
                                if (cmd->cmd.end_state->end_state != -1)
                                        rlink_end_state(cmd->cmd.end_state->end_state);
                                break;
                        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_reset_config & RESET_SRST_PULLS_TRST)))
                                {
                                        cur_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_STATEMOVE:
#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\".\n", speed);
                                exit(1);
                        }
        
                        if(dtc_start_download() < 0) {
                                LOG_ERROR("%s, %d: starting DTC: %s",
                                        __FILE__, __LINE__,
                                        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);
}


#if 0
static
int
handle_dtc_directory_command(
        struct command_context_s *cmd_ctx,
        char *cmd,
        char **args,
        int argc
) {
        if(argc != 1) {
                LOG_ERROR("expected exactly one argument to rlink_dtc_directory <directory-path>");
                return(ERROR_INVALID_ARGUMENTS);
        }

        printf("handle_dtc_directory_command called with \"%s\"\n", args[0]);

        return(ERROR_OK);
}
#endif


static
int rlink_register_commands(struct command_context_s *cmd_ctx)
{

#ifdef _DEBUG_JTAG_IO_
        LOG_DEBUG("rlink_register_commands called with cmd_ctx=%p\n", cmd_ctx);
#endif

#if 0
        register_command(
                cmd_ctx, NULL,
                "rlink_dtc_directory",
                handle_dtc_directory_command,
                COMMAND_CONFIG,
                "The directory in which to search for DTC load images"
        );
#endif

        return ERROR_OK;
}


static
int rlink_init(void)
{
        struct usb_bus *busses;
        struct usb_bus *bus;
        int i, j, retries;
        int found=0;
        int success=0;
        u8 reply_buffer[USB_EP1IN_SIZE];

        usb_init();
        usb_find_busses();
        usb_find_devices();

        busses = usb_get_busses();

        for(bus = busses; bus; bus = bus->next)
        {
                struct usb_device *dev;

                for(dev = bus->devices; dev; dev = dev->next)
                {
                        if( (dev->descriptor.idVendor == USB_IDVENDOR) && (dev->descriptor.idProduct == USB_IDPRODUCT) )
                        {
                                found = 1;
                                LOG_DEBUG("Found device on bus.\n");

                                do
                                {
                                        if( dev->descriptor.bNumConfigurations > 1 )
                                        {
                                                LOG_ERROR("Whoops! NumConfigurations is not 1, don't know what to do...\n");
                                                break;
                                        }
                                        if( dev->config->bNumInterfaces > 1 )
                                        {
                                                LOG_ERROR("Whoops! NumInterfaces is not 1, don't know what to do...\n");
                                                break;
                                        }

                                        pHDev=usb_open(dev);
                                        if( !pHDev )
                                                LOG_ERROR ("Failed to open device.\n");
                                        else
                                        {
                                                LOG_DEBUG("Opened device, pHDev = %p\n",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!\n");
                                                                break;
                                                        }
                                                } while(--retries);

                                                if(!i)
                                                {
                                                        if( usb_set_altinterface(pHDev,0) )
                                                        {
                                                                LOG_ERROR("Failed to set interface.\n");
                                                                break;
                                                        }
                                                        else
                                                                success=1;
                                                }
                                        }
                                } while(0);
                        }
                }
        }

        if( !found )
        {
                LOG_ERROR("No device found on bus.\n");
                exit(1);
        }

        if( !success )
        {
                LOG_ERROR("Initialisation failed.");
                exit(1);
        }


        /* 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'll 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\n", 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.\n");
        }

        /* 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,
                        ST7_PE_ADAPTER_SENSE_OUT,
                        ST7_PE_ADAPTER_SENSE_OUT,
                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\n");
        }

        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,
                        0x00,
                        0x00
        );

        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\n");
        }

        /* float port A, make sure DTC is stopped, set upper 2 bits of port D, and set up port A */
        ep1_generic_commandl(
                pHDev, 15,
                EP1_CMD_MEMORY_WRITE,
                        ST7_PADDR >> 8,
                        ST7_PADDR,
                        2,
                        0x00,
                        0x00,
                EP1_CMD_DTC_STOP,
                EP1_CMD_SET_PORTD_UPPER,
                        ~(ST7_PD_NRUN_LED),
                EP1_CMD_MEMORY_WRITE,
                        ST7_PADR >> 8,
                        ST7_PADR,
                        2,
                        ((~(ST7_PA_NLINE_DRIVER_ENABLE)) & ST7_PA_NUNASSERTED),
                        (ST7_PA_NLINE_DRIVER_ENABLE | ST7_PA_NRLINK_RST | ST7_PA_NJTAG_TRST)
        );

        /* 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_speed(jtag_speed);
        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_UPPER,
                        ~0
        );

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


        return ERROR_OK;
}


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