or1k_du_adv.c

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// SPDX-License-Identifier: GPL-2.0-or-later
 
/***************************************************************************
 *   Copyright (C) 2013-2014 by Franck Jullien                             *
 *   elec4fun@gmail.com                                                    *
 *                                                                         *
 *   Inspired from adv_jtag_bridge which is:                               *
 *   Copyright (C) 2008-2010 Nathan Yawn                                   *
 *   nyawn@opencores.net                                                   *
 *                                                                         *
 *   And the Mohor interface version of this file which is:                *
 *   Copyright (C) 2011 by Julius Baxter                                   *
 *   julius@opencores.org                                                  *
 ***************************************************************************/
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
 
#include "or1k_tap.h"
#include "or1k.h"
#include "or1k_du.h"
#include "jsp_server.h"
 
#include <target/target.h>
#include <jtag/jtag.h>
 
#define JSP_BANNER "\n\r" \
           "******************************\n\r" \
           "**     JTAG Serial Port     **\n\r" \
           "******************************\n\r" \
           "\n\r"
 
#define NO_OPTION           0
 
/* This an option to the adv debug unit.
 * If this is defined, status bits will be skipped on burst
 * reads and writes to improve download speeds.
 * This option must match the RTL configured option.
 */
#define ADBG_USE_HISPEED        1
 
/* This an option to the adv debug unit.
 * If this is defined, the JTAG Serial Port Server is started.
 * This option must match the RTL configured option.
 */
#define ENABLE_JSP_SERVER       2
 
/* Define this if you intend to use the JSP in a system with multiple
 * devices on the JTAG chain
 */
#define ENABLE_JSP_MULTI        4
 
/* Definitions for the top-level debug unit.  This really just consists
 * of a single register, used to select the active debug module ("chain").
 */
#define DBG_MODULE_SELECT_REG_SIZE  2
#define DBG_MAX_MODULES         4
 
#define DC_NONE             -1
#define DC_WISHBONE         0
#define DC_CPU0             1
#define DC_CPU1             2
#define DC_JSP              3
 
/* CPU control register bits mask */
#define DBG_CPU_CR_STALL        0x01
#define DBG_CPU_CR_RESET        0x02
 
/* Polynomial for the CRC calculation
 * Yes, it's backwards.  Yes, this is on purpose.
 * The hardware is designed this way to save on logic and routing,
 * and it's really all the same to us here.
 */
#define ADBG_CRC_POLY           0xedb88320
 
/* These are for the internal registers in the Wishbone module
 * The first is the length of the index register,
 * the indexes of the various registers are defined after that.
 */
#define DBG_WB_REG_SEL_LEN      1
#define DBG_WB_REG_ERROR        0
 
/* Opcode definitions for the Wishbone module. */
#define DBG_WB_OPCODE_LEN       4
#define DBG_WB_CMD_NOP          0x0
#define DBG_WB_CMD_BWRITE8      0x1
#define DBG_WB_CMD_BWRITE16     0x2
#define DBG_WB_CMD_BWRITE32     0x3
#define DBG_WB_CMD_BREAD8       0x5
#define DBG_WB_CMD_BREAD16      0x6
#define DBG_WB_CMD_BREAD32      0x7
#define DBG_WB_CMD_IREG_WR      0x9
#define DBG_WB_CMD_IREG_SEL     0xd
 
/* Internal register definitions for the CPU0 module. */
#define DBG_CPU0_REG_SEL_LEN        1
#define DBG_CPU0_REG_STATUS     0
 
/* Opcode definitions for the first CPU module. */
#define DBG_CPU0_OPCODE_LEN     4
#define DBG_CPU0_CMD_NOP        0x0
#define DBG_CPU0_CMD_BWRITE32       0x3
#define DBG_CPU0_CMD_BREAD32        0x7
#define DBG_CPU0_CMD_IREG_WR        0x9
#define DBG_CPU0_CMD_IREG_SEL       0xd
 
/* Internal register definitions for the CPU1 module. */
#define DBG_CPU1_REG_SEL_LEN        1
#define DBG_CPU1_REG_STATUS     0
 
/* Opcode definitions for the second CPU module. */
#define DBG_CPU1_OPCODE_LEN     4
#define DBG_CPU1_CMD_NOP        0x0
#define DBG_CPU1_CMD_BWRITE32       0x3
#define DBG_CPU1_CMD_BREAD32        0x7
#define DBG_CPU1_CMD_IREG_WR        0x9
#define DBG_CPU1_CMD_IREG_SEL       0xd
 
#define MAX_READ_STATUS_WAIT        10
#define MAX_READ_BUSY_RETRY     2
#define MAX_READ_CRC_RETRY      2
#define MAX_WRITE_CRC_RETRY     2
#define BURST_READ_READY        1
#define MAX_BUS_ERRORS          2
 
#define MAX_BURST_SIZE          (4 * 1024)
 
#define STATUS_BYTES            1
#define CRC_LEN             4
 
static struct or1k_du or1k_du_adv;
 
static const char * const chain_name[] = {"WISHBONE", "CPU0", "CPU1", "JSP"};
 
static uint32_t adbg_compute_crc(uint32_t crc, uint32_t data_in,
                 int length_bits)
{
    for (int i = 0; i < length_bits; i++) {
        uint32_t d, c;
        d = ((data_in >> i) & 0x1) ? 0xffffffff : 0;
        c = (crc & 0x1) ? 0xffffffff : 0;
        crc = crc >> 1;
        crc = crc ^ ((d ^ c) & ADBG_CRC_POLY);
    }
 
    return crc;
}
 
static int find_status_bit(void *_buf, int len)
{
    int i = 0;
    int count = 0;
    int ret = -1;
    uint8_t *buf = _buf;
 
    while (!(buf[i] & (1 << count++)) && (i < len)) {
        if (count == 8) {
            count = 0;
            i++;
        }
    }
 
    if (i < len)
        ret = (i * 8) + count;
 
    return ret;
}
 
static int or1k_adv_jtag_init(struct or1k_jtag *jtag_info)
{
    struct or1k_tap_ip *tap_ip = jtag_info->tap_ip;
 
    int retval = tap_ip->init(jtag_info);
    if (retval != ERROR_OK) {
        LOG_ERROR("TAP initialization failed");
        return retval;
    }
 
    /* TAP is now configured to communicate with debug interface */
    jtag_info->or1k_jtag_inited = 1;
 
    /* TAP reset - not sure what state debug module chain is in now */
    jtag_info->or1k_jtag_module_selected = DC_NONE;
 
    jtag_info->current_reg_idx = malloc(DBG_MAX_MODULES * sizeof(uint8_t));
    memset(jtag_info->current_reg_idx, 0, DBG_MAX_MODULES * sizeof(uint8_t));
 
    if (or1k_du_adv.options & ADBG_USE_HISPEED)
        LOG_INFO("adv debug unit is configured with option ADBG_USE_HISPEED");
 
    if (or1k_du_adv.options & ENABLE_JSP_SERVER) {
        if (or1k_du_adv.options & ENABLE_JSP_MULTI)
            LOG_INFO("adv debug unit is configured with option ENABLE_JSP_MULTI");
        LOG_INFO("adv debug unit is configured with option ENABLE_JSP_SERVER");
        retval = jsp_init(jtag_info, JSP_BANNER);
        if (retval != ERROR_OK) {
            LOG_ERROR("Couldn't start the JSP server");
            return retval;
        }
    }
 
    LOG_DEBUG("Init done");
 
    return ERROR_OK;
 
}
 
/* Selects one of the modules in the debug unit
 * (e.g. wishbone unit, CPU0, etc.)
 */
static int adbg_select_module(struct or1k_jtag *jtag_info, int chain)
{
    if (jtag_info->or1k_jtag_module_selected == chain)
        return ERROR_OK;
 
    /* MSB of the data out must be set to 1, indicating a module
     * select command
     */
    uint8_t data = chain | (1 << DBG_MODULE_SELECT_REG_SIZE);
 
    LOG_DEBUG("Select module: %s", chain_name[chain]);
 
    struct scan_field field;
 
    field.num_bits = (DBG_MODULE_SELECT_REG_SIZE + 1);
    field.out_value = &data;
    field.in_value = NULL;
    jtag_add_dr_scan(jtag_info->tap, 1, &field, TAP_IDLE);
 
    int retval = jtag_execute_queue();
    if (retval != ERROR_OK)
        return retval;
 
    jtag_info->or1k_jtag_module_selected = chain;
 
    return ERROR_OK;
}
 
/* Set the index of the desired register in the currently selected module
 * 1 bit module select command
 * 4 bits opcode
 * n bits index
 */
static int adbg_select_ctrl_reg(struct or1k_jtag *jtag_info, uint8_t regidx)
{
    int index_len;
    uint32_t opcode;
    uint32_t opcode_len;
 
    /* If this reg is already selected, don't do a JTAG transaction */
    if (jtag_info->current_reg_idx[jtag_info->or1k_jtag_module_selected] == regidx)
        return ERROR_OK;
 
    switch (jtag_info->or1k_jtag_module_selected) {
    case DC_WISHBONE:
        index_len = DBG_WB_REG_SEL_LEN;
        opcode = DBG_WB_CMD_IREG_SEL;
        opcode_len = DBG_WB_OPCODE_LEN;
        break;
    case DC_CPU0:
        index_len = DBG_CPU0_REG_SEL_LEN;
        opcode = DBG_CPU0_CMD_IREG_SEL;
        opcode_len = DBG_CPU0_OPCODE_LEN;
        break;
    case DC_CPU1:
        index_len = DBG_CPU1_REG_SEL_LEN;
        opcode = DBG_CPU1_CMD_IREG_SEL;
        opcode_len = DBG_CPU1_OPCODE_LEN;
        break;
    default:
        LOG_ERROR("Illegal debug chain selected (%i) while selecting control register",
              jtag_info->or1k_jtag_module_selected);
        return ERROR_FAIL;
    }
 
    /* MSB must be 0 to access modules */
    uint32_t data = (opcode & ~(1 << opcode_len)) << index_len;
    data |= regidx;
 
    struct scan_field field;
 
    field.num_bits = (opcode_len + 1) + index_len;
    field.out_value = (uint8_t *)&data;
    field.in_value = NULL;
    jtag_add_dr_scan(jtag_info->tap, 1, &field, TAP_IDLE);
 
    int retval = jtag_execute_queue();
    if (retval != ERROR_OK)
        return retval;
 
    jtag_info->current_reg_idx[jtag_info->or1k_jtag_module_selected] = regidx;
 
    return ERROR_OK;
}
 
/* Write control register (internal to the debug unit) */
static int adbg_ctrl_write(struct or1k_jtag *jtag_info, uint8_t regidx,
               uint32_t *cmd_data, int length_bits)
{
    int index_len;
    uint32_t opcode;
    uint32_t opcode_len;
 
    LOG_DEBUG("Write control register %" PRId8 ": 0x%08" PRIx32, regidx, cmd_data[0]);
 
    int retval = adbg_select_ctrl_reg(jtag_info, regidx);
    if (retval != ERROR_OK) {
        LOG_ERROR("Error while calling adbg_select_ctrl_reg");
        return retval;
    }
 
    switch (jtag_info->or1k_jtag_module_selected) {
    case DC_WISHBONE:
        index_len = DBG_WB_REG_SEL_LEN;
        opcode = DBG_WB_CMD_IREG_WR;
        opcode_len = DBG_WB_OPCODE_LEN;
        break;
    case DC_CPU0:
        index_len = DBG_CPU0_REG_SEL_LEN;
        opcode = DBG_CPU0_CMD_IREG_WR;
        opcode_len = DBG_CPU0_OPCODE_LEN;
        break;
    case DC_CPU1:
        index_len = DBG_CPU1_REG_SEL_LEN;
        opcode = DBG_CPU1_CMD_IREG_WR;
        opcode_len = DBG_CPU1_OPCODE_LEN;
        break;
    default:
        LOG_ERROR("Illegal debug chain selected (%i) while doing control write",
              jtag_info->or1k_jtag_module_selected);
        return ERROR_FAIL;
    }
 
    struct scan_field field[2];
 
    /* MSB must be 0 to access modules */
    uint32_t data = (opcode & ~(1 << opcode_len)) << index_len;
    data |= regidx;
 
    field[0].num_bits = length_bits;
    field[0].out_value = (uint8_t *)cmd_data;
    field[0].in_value = NULL;
 
    field[1].num_bits = (opcode_len + 1) + index_len;
    field[1].out_value = (uint8_t *)&data;
    field[1].in_value = NULL;
 
    jtag_add_dr_scan(jtag_info->tap, 2, field, TAP_IDLE);
 
    return jtag_execute_queue();
}
 
/* Reads control register (internal to the debug unit) */
static int adbg_ctrl_read(struct or1k_jtag *jtag_info, uint32_t regidx,
              uint32_t *data, int length_bits)
{
 
    int retval = adbg_select_ctrl_reg(jtag_info, regidx);
    if (retval != ERROR_OK) {
        LOG_ERROR("Error while calling adbg_select_ctrl_reg");
        return retval;
    }
 
    int opcode_len;
    uint32_t opcode;
 
    /* There is no 'read' command, We write a NOP to read */
    switch (jtag_info->or1k_jtag_module_selected) {
    case DC_WISHBONE:
        opcode = DBG_WB_CMD_NOP;
        opcode_len = DBG_WB_OPCODE_LEN;
        break;
    case DC_CPU0:
        opcode = DBG_CPU0_CMD_NOP;
        opcode_len = DBG_CPU0_OPCODE_LEN;
        break;
    case DC_CPU1:
        opcode = DBG_CPU1_CMD_NOP;
        opcode_len = DBG_CPU1_OPCODE_LEN;
        break;
    default:
        LOG_ERROR("Illegal debug chain selected (%i) while doing control read",
              jtag_info->or1k_jtag_module_selected);
         return ERROR_FAIL;
    }
 
    /* Zero MSB = op for module, not top-level debug unit */
    uint32_t outdata = opcode & ~(0x1 << opcode_len);
 
    struct scan_field field[2];
 
    field[0].num_bits = length_bits;
    field[0].out_value = NULL;
    field[0].in_value = (uint8_t *)data;
 
    field[1].num_bits = opcode_len + 1;
    field[1].out_value = (uint8_t *)&outdata;
    field[1].in_value = NULL;
 
    jtag_add_dr_scan(jtag_info->tap, 2, field, TAP_IDLE);
 
    return jtag_execute_queue();
}
 
/* sends out a burst command to the selected module in the debug unit (MSB to LSB):
 * 1-bit module command
 * 4-bit opcode
 * 32-bit address
 * 16-bit length (of the burst, in words)
 */
static int adbg_burst_command(struct or1k_jtag *jtag_info, uint32_t opcode,
                  uint32_t address, uint16_t length_words)
{
    uint32_t data[2];
 
    /* Set up the data */
    data[0] = length_words | (address << 16);
    /* MSB must be 0 to access modules */
    data[1] = ((address >> 16) | ((opcode & 0xf) << 16)) & ~(0x1 << 20);
 
    struct scan_field field;
 
    field.num_bits = 53;
    field.out_value = (uint8_t *)&data[0];
    field.in_value = NULL;
 
    jtag_add_dr_scan(jtag_info->tap, 1, &field, TAP_IDLE);
 
    return jtag_execute_queue();
}
 
static int adbg_wb_burst_read(struct or1k_jtag *jtag_info, int size,
                  int count, uint32_t start_address, uint8_t *data)
{
    int retry_full_crc = 0;
    int retry_full_busy = 0;
    int retval;
    uint8_t opcode;
 
    LOG_DEBUG("Doing burst read, word size %d, word count %d, start address 0x%08" PRIx32,
          size, count, start_address);
 
    /* Select the appropriate opcode */
    switch (jtag_info->or1k_jtag_module_selected) {
    case DC_WISHBONE:
        if (size == 1)
            opcode = DBG_WB_CMD_BREAD8;
        else if (size == 2)
            opcode = DBG_WB_CMD_BREAD16;
        else if (size == 4)
            opcode = DBG_WB_CMD_BREAD32;
        else {
            LOG_WARNING("Tried burst read with invalid word size (%d),"
                  "defaulting to 4-byte words", size);
            opcode = DBG_WB_CMD_BREAD32;
        }
        break;
    case DC_CPU0:
        if (size == 4)
            opcode = DBG_CPU0_CMD_BREAD32;
        else {
            LOG_WARNING("Tried burst read with invalid word size (%d),"
                  "defaulting to 4-byte words", size);
            opcode = DBG_CPU0_CMD_BREAD32;
        }
        break;
    case DC_CPU1:
        if (size == 4)
            opcode = DBG_CPU1_CMD_BREAD32;
        else {
            LOG_WARNING("Tried burst read with invalid word size (%d),"
                  "defaulting to 4-byte words", size);
            opcode = DBG_CPU0_CMD_BREAD32;
        }
        break;
    default:
        LOG_ERROR("Illegal debug chain selected (%i) while doing burst read",
              jtag_info->or1k_jtag_module_selected);
        return ERROR_FAIL;
    }
 
    int total_size_bytes = count * size;
    struct scan_field field;
    uint8_t *in_buffer = malloc(total_size_bytes + CRC_LEN + STATUS_BYTES);
 
retry_read_full:
 
    /* Send the BURST READ command, returns TAP to idle state */
    retval = adbg_burst_command(jtag_info, opcode, start_address, count);
    if (retval != ERROR_OK)
        goto out;
 
    field.num_bits = (total_size_bytes + CRC_LEN + STATUS_BYTES) * 8;
    field.out_value = NULL;
    field.in_value = in_buffer;
 
    jtag_add_dr_scan(jtag_info->tap, 1, &field, TAP_IDLE);
 
    retval = jtag_execute_queue();
    if (retval != ERROR_OK)
        goto out;
 
    /* Look for the start bit in the first (STATUS_BYTES * 8) bits */
    int shift = find_status_bit(in_buffer, STATUS_BYTES);
 
    /* We expect the status bit to be in the first byte */
    if (shift < 0) {
        if (retry_full_busy++ < MAX_READ_BUSY_RETRY) {
            LOG_WARNING("Burst read timed out");
            goto retry_read_full;
        } else {
            LOG_ERROR("Burst read failed");
            retval = ERROR_FAIL;
            goto out;
        }
    }
 
    buffer_shr(in_buffer, total_size_bytes + CRC_LEN + STATUS_BYTES, shift);
 
    uint32_t crc_read;
    memcpy(data, in_buffer, total_size_bytes);
    memcpy(&crc_read, &in_buffer[total_size_bytes], 4);
 
    uint32_t crc_calc = 0xffffffff;
    for (int i = 0; i < total_size_bytes; i++)
        crc_calc = adbg_compute_crc(crc_calc, data[i], 8);
 
    if (crc_calc != crc_read) {
        LOG_WARNING("CRC ERROR! Computed 0x%08" PRIx32 ", read CRC 0x%08" PRIx32, crc_calc, crc_read);
        if (retry_full_crc++ < MAX_READ_CRC_RETRY)
            goto retry_read_full;
        else {
            LOG_ERROR("Burst read failed");
            retval = ERROR_FAIL;
            goto out;
        }
    } else
        LOG_DEBUG("CRC OK!");
 
    /* Now, read the error register, and retry/recompute as necessary */
    if (jtag_info->or1k_jtag_module_selected == DC_WISHBONE &&
        !(or1k_du_adv.options & ADBG_USE_HISPEED)) {
 
        uint32_t err_data[2] = {0, 0};
        uint32_t addr;
        int bus_error_retries = 0;
 
        /* First, just get 1 bit...read address only if necessary */
        retval = adbg_ctrl_read(jtag_info, DBG_WB_REG_ERROR, err_data, 1);
        if (retval != ERROR_OK)
            goto out;
 
        /* Then we have a problem */
        if (err_data[0] & 0x1) {
 
            retval = adbg_ctrl_read(jtag_info, DBG_WB_REG_ERROR, err_data, 33);
            if (retval != ERROR_OK)
                goto out;
 
            addr = (err_data[0] >> 1) | (err_data[1] << 31);
            LOG_WARNING("WB bus error during burst read, address 0x%08" PRIx32 ", retrying!", addr);
 
            bus_error_retries++;
            if (bus_error_retries > MAX_BUS_ERRORS) {
                LOG_ERROR("Max WB bus errors reached during burst read");
                retval = ERROR_FAIL;
                goto out;
            }
 
            /* Don't call retry_do(), a JTAG reset won't help a WB bus error */
            /* Write 1 bit, to reset the error register */
            err_data[0] = 1;
            retval = adbg_ctrl_write(jtag_info, DBG_WB_REG_ERROR, err_data, 1);
            if (retval != ERROR_OK)
                goto out;
 
            goto retry_read_full;
        }
    }
 
out:
    free(in_buffer);
 
    return retval;
}
 
/* Set up and execute a burst write to a contiguous set of addresses */
static int adbg_wb_burst_write(struct or1k_jtag *jtag_info, const uint8_t *data, int size,
            int count, unsigned long start_address)
{
    int retry_full_crc = 0;
    int retval;
    uint8_t opcode;
 
    LOG_DEBUG("Doing burst write, word size %d, word count %d,"
          "start address 0x%08lx", size, count, start_address);
 
    /* Select the appropriate opcode */
    switch (jtag_info->or1k_jtag_module_selected) {
    case DC_WISHBONE:
        if (size == 1)
            opcode = DBG_WB_CMD_BWRITE8;
        else if (size == 2)
            opcode = DBG_WB_CMD_BWRITE16;
        else if (size == 4)
            opcode = DBG_WB_CMD_BWRITE32;
        else {
            LOG_DEBUG("Tried WB burst write with invalid word size (%d),"
                  "defaulting to 4-byte words", size);
            opcode = DBG_WB_CMD_BWRITE32;
        }
        break;
    case DC_CPU0:
        if (size == 4)
            opcode = DBG_CPU0_CMD_BWRITE32;
        else {
            LOG_DEBUG("Tried CPU0 burst write with invalid word size (%d),"
                  "defaulting to 4-byte words", size);
            opcode = DBG_CPU0_CMD_BWRITE32;
        }
        break;
    case DC_CPU1:
        if (size == 4)
            opcode = DBG_CPU1_CMD_BWRITE32;
        else {
            LOG_DEBUG("Tried CPU1 burst write with invalid word size (%d),"
                  "defaulting to 4-byte words", size);
            opcode = DBG_CPU0_CMD_BWRITE32;
        }
        break;
    default:
        LOG_ERROR("Illegal debug chain selected (%i) while doing burst write",
              jtag_info->or1k_jtag_module_selected);
        return ERROR_FAIL;
    }
 
retry_full_write:
 
    /* Send the BURST WRITE command, returns TAP to idle state */
    retval = adbg_burst_command(jtag_info, opcode, start_address, count);
    if (retval != ERROR_OK)
        return retval;
 
    struct scan_field field[3];
 
    /* Write a start bit so it knows when to start counting */
    uint8_t value = 1;
    field[0].num_bits = 1;
    field[0].out_value = &value;
    field[0].in_value = NULL;
 
    uint32_t crc_calc = 0xffffffff;
    for (int i = 0; i < (count * size); i++)
        crc_calc = adbg_compute_crc(crc_calc, data[i], 8);
 
    field[1].num_bits = count * size * 8;
    field[1].out_value = data;
    field[1].in_value = NULL;
 
    field[2].num_bits = 32;
    field[2].out_value = (uint8_t *)&crc_calc;
    field[2].in_value = NULL;
 
    jtag_add_dr_scan(jtag_info->tap, 3, field, TAP_DRSHIFT);
 
    /* Read the 'CRC match' bit, and go to idle */
    field[0].num_bits = 1;
    field[0].out_value = NULL;
    field[0].in_value = &value;
    jtag_add_dr_scan(jtag_info->tap, 1, field, TAP_IDLE);
 
    retval = jtag_execute_queue();
    if (retval != ERROR_OK)
        return retval;
 
    if (!value) {
        LOG_WARNING("CRC ERROR! match bit after write is %" PRIi8 " (computed CRC 0x%08" PRIx32 ")", value, crc_calc);
        if (retry_full_crc++ < MAX_WRITE_CRC_RETRY)
            goto retry_full_write;
        else
            return ERROR_FAIL;
    } else
        LOG_DEBUG("CRC OK!\n");
 
    /* Now, read the error register, and retry/recompute as necessary */
    if (jtag_info->or1k_jtag_module_selected == DC_WISHBONE &&
        !(or1k_du_adv.options & ADBG_USE_HISPEED)) {
        uint32_t addr;
        int bus_error_retries = 0;
        uint32_t err_data[2] = {0, 0};
 
        /* First, just get 1 bit...read address only if necessary */
        retval = adbg_ctrl_read(jtag_info, DBG_WB_REG_ERROR, err_data, 1);
        if (retval != ERROR_OK)
            return retval;
 
        /* Then we have a problem */
        if (err_data[0] & 0x1) {
 
            retval = adbg_ctrl_read(jtag_info, DBG_WB_REG_ERROR, err_data, 33);
            if (retval != ERROR_OK)
                return retval;
 
            addr = (err_data[0] >> 1) | (err_data[1] << 31);
            LOG_WARNING("WB bus error during burst write, address 0x%08" PRIx32 ", retrying!", addr);
 
            bus_error_retries++;
            if (bus_error_retries > MAX_BUS_ERRORS) {
                LOG_ERROR("Max WB bus errors reached during burst read");
                retval = ERROR_FAIL;
                return retval;
            }
 
            /* Don't call retry_do(), a JTAG reset won't help a WB bus error */
            /* Write 1 bit, to reset the error register */
            err_data[0] = 1;
            retval = adbg_ctrl_write(jtag_info, DBG_WB_REG_ERROR, err_data, 1);
            if (retval != ERROR_OK)
                return retval;
 
            goto retry_full_write;
        }
    }
 
    return ERROR_OK;
}
 
/* Currently hard set in functions to 32-bits */
static int or1k_adv_jtag_read_cpu(struct or1k_jtag *jtag_info,
        uint32_t addr, int count, uint32_t *value)
{
    int retval;
    if (!jtag_info->or1k_jtag_inited) {
        retval = or1k_adv_jtag_init(jtag_info);
        if (retval != ERROR_OK)
            return retval;
    }
 
    retval = adbg_select_module(jtag_info, DC_CPU0);
    if (retval != ERROR_OK)
        return retval;
 
    return adbg_wb_burst_read(jtag_info, 4, count, addr, (uint8_t *)value);
}
 
static int or1k_adv_jtag_write_cpu(struct or1k_jtag *jtag_info,
        uint32_t addr, int count, const uint32_t *value)
{
    int retval;
    if (!jtag_info->or1k_jtag_inited) {
        retval = or1k_adv_jtag_init(jtag_info);
        if (retval != ERROR_OK)
            return retval;
    }
 
    retval = adbg_select_module(jtag_info, DC_CPU0);
    if (retval != ERROR_OK)
        return retval;
 
    return adbg_wb_burst_write(jtag_info, (uint8_t *)value, 4, count, addr);
}
 
static int or1k_adv_cpu_stall(struct or1k_jtag *jtag_info, int action)
{
    int retval;
    if (!jtag_info->or1k_jtag_inited) {
        retval = or1k_adv_jtag_init(jtag_info);
        if (retval != ERROR_OK)
            return retval;
    }
 
    retval = adbg_select_module(jtag_info, DC_CPU0);
    if (retval != ERROR_OK)
        return retval;
 
    uint32_t cpu_cr;
    retval = adbg_ctrl_read(jtag_info, DBG_CPU0_REG_STATUS, &cpu_cr, 2);
    if (retval != ERROR_OK)
        return retval;
 
    if (action == CPU_STALL)
        cpu_cr |= DBG_CPU_CR_STALL;
    else
        cpu_cr &= ~DBG_CPU_CR_STALL;
 
    retval = adbg_select_module(jtag_info, DC_CPU0);
    if (retval != ERROR_OK)
        return retval;
 
    return adbg_ctrl_write(jtag_info, DBG_CPU0_REG_STATUS, &cpu_cr, 2);
}
 
static int or1k_adv_is_cpu_running(struct or1k_jtag *jtag_info, int *running)
{
    int retval;
    if (!jtag_info->or1k_jtag_inited) {
        retval = or1k_adv_jtag_init(jtag_info);
        if (retval != ERROR_OK)
            return retval;
    }
 
    int current = jtag_info->or1k_jtag_module_selected;
 
    retval = adbg_select_module(jtag_info, DC_CPU0);
    if (retval != ERROR_OK)
        return retval;
 
    uint32_t cpu_cr = 0;
    retval = adbg_ctrl_read(jtag_info, DBG_CPU0_REG_STATUS, &cpu_cr, 2);
    if (retval != ERROR_OK)
        return retval;
 
    if (cpu_cr & DBG_CPU_CR_STALL)
        *running = 0;
    else
        *running = 1;
 
    if (current != DC_NONE) {
        retval = adbg_select_module(jtag_info, current);
        if (retval != ERROR_OK)
            return retval;
    }
 
    return ERROR_OK;
}
 
static int or1k_adv_cpu_reset(struct or1k_jtag *jtag_info, int action)
{
    int retval;
    if (!jtag_info->or1k_jtag_inited) {
        retval = or1k_adv_jtag_init(jtag_info);
        if (retval != ERROR_OK)
            return retval;
    }
 
    retval = adbg_select_module(jtag_info, DC_CPU0);
    if (retval != ERROR_OK)
        return retval;
 
    uint32_t cpu_cr;
    retval = adbg_ctrl_read(jtag_info, DBG_CPU0_REG_STATUS, &cpu_cr, 2);
    if (retval != ERROR_OK)
        return retval;
 
    if (action == CPU_RESET)
        cpu_cr |= DBG_CPU_CR_RESET;
    else
        cpu_cr &= ~DBG_CPU_CR_RESET;
 
    retval = adbg_select_module(jtag_info, DC_CPU0);
    if (retval != ERROR_OK)
        return retval;
 
    return adbg_ctrl_write(jtag_info, DBG_CPU0_REG_STATUS, &cpu_cr, 2);
}
 
static int or1k_adv_jtag_read_memory(struct or1k_jtag *jtag_info,
                uint32_t addr, uint32_t size, int count, uint8_t *buffer)
{
    LOG_DEBUG("Reading WB%" PRIu32 " at 0x%08" PRIx32, size * 8, addr);
 
    int retval;
    if (!jtag_info->or1k_jtag_inited) {
        retval = or1k_adv_jtag_init(jtag_info);
        if (retval != ERROR_OK)
            return retval;
    }
 
    retval = adbg_select_module(jtag_info, DC_WISHBONE);
    if (retval != ERROR_OK)
        return retval;
 
    int block_count_left = count;
    uint32_t block_count_address = addr;
    uint8_t *block_count_buffer = buffer;
 
    while (block_count_left) {
 
        int blocks_this_round = (block_count_left > MAX_BURST_SIZE) ?
            MAX_BURST_SIZE : block_count_left;
 
        retval = adbg_wb_burst_read(jtag_info, size, blocks_this_round,
                        block_count_address, block_count_buffer);
        if (retval != ERROR_OK)
            return retval;
 
        block_count_left -= blocks_this_round;
        block_count_address += size * MAX_BURST_SIZE;
        block_count_buffer += size * MAX_BURST_SIZE;
    }
 
    /* The adv_debug_if always return words and half words in
     * little-endian order no matter what the target endian is.
     * So if the target endian is big, change the order.
     */
 
    struct target *target = jtag_info->target;
    if ((target->endianness == TARGET_BIG_ENDIAN) && (size != 1)) {
        switch (size) {
        case 4:
            buf_bswap32(buffer, buffer, size * count);
            break;
        case 2:
            buf_bswap16(buffer, buffer, size * count);
            break;
        }
    }
 
    return ERROR_OK;
}
 
static int or1k_adv_jtag_write_memory(struct or1k_jtag *jtag_info,
                 uint32_t addr, uint32_t size, int count, const uint8_t *buffer)
{
    LOG_DEBUG("Writing WB%" PRIu32 " at 0x%08" PRIx32, size * 8, addr);
 
    int retval;
    if (!jtag_info->or1k_jtag_inited) {
        retval = or1k_adv_jtag_init(jtag_info);
        if (retval != ERROR_OK)
            return retval;
    }
 
    retval = adbg_select_module(jtag_info, DC_WISHBONE);
    if (retval != ERROR_OK)
        return retval;
 
    /* The adv_debug_if wants words and half words in little-endian
     * order no matter what the target endian is. So if the target
     * endian is big, change the order.
     */
 
    void *t = NULL;
    struct target *target = jtag_info->target;
    if ((target->endianness == TARGET_BIG_ENDIAN) && (size != 1)) {
        t = calloc(count * size, sizeof(uint8_t));
        if (!t) {
            LOG_ERROR("Out of memory");
            return ERROR_FAIL;
        }
 
        switch (size) {
        case 4:
            buf_bswap32(t, buffer, size * count);
            break;
        case 2:
            buf_bswap16(t, buffer, size * count);
            break;
        default:
            free(t);
            return ERROR_TARGET_FAILURE;
        }
        buffer = t;
    }
 
    int block_count_left = count;
    uint32_t block_count_address = addr;
    uint8_t *block_count_buffer = (uint8_t *)buffer;
 
    while (block_count_left) {
 
        int blocks_this_round = (block_count_left > MAX_BURST_SIZE) ?
            MAX_BURST_SIZE : block_count_left;
 
        retval = adbg_wb_burst_write(jtag_info, block_count_buffer,
                         size, blocks_this_round,
                         block_count_address);
        if (retval != ERROR_OK) {
            free(t);
            return retval;
        }
 
        block_count_left -= blocks_this_round;
        block_count_address += size * MAX_BURST_SIZE;
        block_count_buffer += size * MAX_BURST_SIZE;
    }
 
    free(t);
    return ERROR_OK;
}
 
int or1k_adv_jtag_jsp_xfer(struct or1k_jtag *jtag_info,
                  int *out_len, unsigned char *out_buffer,
                  int *in_len, unsigned char *in_buffer)
{
    LOG_DEBUG("JSP transfer");
 
    int retval;
    if (!jtag_info->or1k_jtag_inited)
        return ERROR_OK;
 
    retval = adbg_select_module(jtag_info, DC_JSP);
    if (retval != ERROR_OK)
        return retval;
 
    /* return nb char xmit */
    int xmitsize;
    if (*out_len > 8)
        xmitsize = 8;
    else
        xmitsize = *out_len;
 
    uint8_t out_data[10];
    uint8_t in_data[10];
    struct scan_field field;
    int startbit, stopbit, wrapbit;
 
    memset(out_data, 0, 10);
 
    if (or1k_du_adv.options & ENABLE_JSP_MULTI) {
 
        startbit = 1;
        wrapbit = (xmitsize >> 3) & 0x1;
        out_data[0] = (xmitsize << 5) | 0x1;  /* set the start bit */
 
        int i;
        /* don't copy off the end of the input array */
        for (i = 0; i < xmitsize; i++) {
            out_data[i + 1] = (out_buffer[i] << 1) | wrapbit;
            wrapbit = (out_buffer[i] >> 7) & 0x1;
        }
 
        if (i < 8)
            out_data[i + 1] = wrapbit;
        else
            out_data[9] = wrapbit;
 
        /* If the last data bit is a '1', then we need to append a '0' so the top-level module
         * won't treat the burst as a 'module select' command.
         */
        stopbit = !!(out_data[9] & 0x01);
 
    } else {
        startbit = 0;
        /* First byte out has write count in upper nibble */
        out_data[0] = 0x0 | (xmitsize << 4);
        if (xmitsize > 0)
            memcpy(&out_data[1], out_buffer, xmitsize);
 
        /* If the last data bit is a '1', then we need to append a '0' so the top-level module
         * won't treat the burst as a 'module select' command.
         */
        stopbit = !!(out_data[8] & 0x80);
    }
 
    field.num_bits = 72 + startbit + stopbit;
    field.out_value = out_data;
    field.in_value = in_data;
 
    jtag_add_dr_scan(jtag_info->tap, 1, &field, TAP_IDLE);
 
    retval = jtag_execute_queue();
    if (retval != ERROR_OK)
        return retval;
 
    /* bytes available is in the upper nibble */
    *in_len = (in_data[0] >> 4) & 0xF;
    memcpy(in_buffer, &in_data[1], *in_len);
 
    int bytes_free = in_data[0] & 0x0F;
    *out_len = (bytes_free < xmitsize) ? bytes_free : xmitsize;
 
    return ERROR_OK;
}
 
static struct or1k_du or1k_du_adv = {
    .name                     = "adv",
    .options                  = NO_OPTION,
    .or1k_jtag_init           = or1k_adv_jtag_init,
 
    .or1k_is_cpu_running      = or1k_adv_is_cpu_running,
    .or1k_cpu_stall           = or1k_adv_cpu_stall,
    .or1k_cpu_reset           = or1k_adv_cpu_reset,
 
    .or1k_jtag_read_cpu       = or1k_adv_jtag_read_cpu,
    .or1k_jtag_write_cpu      = or1k_adv_jtag_write_cpu,
 
    .or1k_jtag_read_memory    = or1k_adv_jtag_read_memory,
    .or1k_jtag_write_memory   = or1k_adv_jtag_write_memory
};
 
int or1k_du_adv_register(void)
{
    list_add_tail(&or1k_du_adv.list, &du_list);
    return 0;
}