ipdbg.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/* Copyright (C) 2020 by Daniel Anselmi <danselmi@gmx.ch> */
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
 
#include <helper/bits.h>
#include <helper/time_support.h>
#include <jtag/jtag.h>
#include <server/server.h>
#include <target/target.h>
 
#include "ipdbg.h"
 
#define IPDBG_BUFFER_SIZE 16384
#define IPDBG_MIN_NUM_OF_OPTIONS 4
#define IPDBG_MAX_NUM_OF_OPTIONS 14
#define IPDBG_MIN_DR_LENGTH 11
#define IPDBG_MAX_DR_LENGTH 13
#define IPDBG_TCP_PORT_STR_MAX_LENGTH 6
 
/* private connection data for IPDBG */
struct ipdbg_fifo {
    size_t count;
    size_t rd_idx;
    char buffer[IPDBG_BUFFER_SIZE];
};
 
struct ipdbg_connection {
    struct ipdbg_fifo dn_fifo;
    struct ipdbg_fifo up_fifo;
    bool closed;
};
 
struct ipdbg_service {
    struct ipdbg_hub *hub;
    struct ipdbg_service *next;
    uint16_t port;
    struct ipdbg_connection connection;
    uint8_t tool;
};
 
struct ipdbg_virtual_ir_info {
    uint32_t instruction;
    uint32_t length;
    uint32_t value;
};
 
struct ipdbg_hub {
    uint32_t user_instruction;
    uint32_t max_tools;
    uint32_t active_connections;
    uint32_t active_services;
    uint32_t valid_mask;
    uint32_t xoff_mask;
    uint32_t tool_mask;
    uint32_t last_dn_tool;
    struct ipdbg_hub *next;
    struct jtag_tap *tap;
    struct connection **connections;
    uint8_t data_register_length;
    uint8_t dn_xoff;
    struct ipdbg_virtual_ir_info *virtual_ir;
};
 
static struct ipdbg_hub *ipdbg_first_hub;
 
static struct ipdbg_service *ipdbg_first_service;
 
static void ipdbg_init_fifo(struct ipdbg_fifo *fifo)
{
    fifo->count = 0;
    fifo->rd_idx = 0;
}
 
static bool ipdbg_fifo_is_empty(struct ipdbg_fifo *fifo)
{
    return fifo->count == 0;
}
 
static bool ipdbg_fifo_is_full(struct ipdbg_fifo *fifo)
{
    return fifo->count == IPDBG_BUFFER_SIZE;
}
 
static void ipdbg_zero_rd_idx(struct ipdbg_fifo *fifo)
{
    if (fifo->rd_idx == 0)
        return;
 
    size_t ri = fifo->rd_idx;
    for (size_t idx = 0 ; idx < fifo->count ; ++idx)
        fifo->buffer[idx] = fifo->buffer[ri++];
    fifo->rd_idx = 0;
}
 
static void ipdbg_append_to_fifo(struct ipdbg_fifo *fifo, char data)
{
    if (ipdbg_fifo_is_full(fifo))
        return;
 
    ipdbg_zero_rd_idx(fifo);
    fifo->buffer[fifo->count++] = data;
}
 
static char ipdbg_get_from_fifo(struct ipdbg_fifo *fifo)
{
    if (ipdbg_fifo_is_empty(fifo))
        return 0;
 
    fifo->count--;
    return fifo->buffer[fifo->rd_idx++];
}
 
static int ipdbg_move_buffer_to_connection(struct connection *conn, struct ipdbg_fifo *fifo)
{
    if (ipdbg_fifo_is_empty(fifo))
        return ERROR_OK;
 
    struct ipdbg_connection *connection = conn->priv;
    if (connection->closed)
        return ERROR_SERVER_REMOTE_CLOSED;
 
    ipdbg_zero_rd_idx(fifo);
    size_t bytes_written = connection_write(conn, fifo->buffer, fifo->count);
    if (bytes_written != fifo->count) {
        LOG_ERROR("error during write: %zu != %zu", bytes_written, fifo->count);
        connection->closed = true;
        return ERROR_SERVER_REMOTE_CLOSED;
    }
 
    fifo->count -= bytes_written;
 
    return ERROR_OK;
}
 
static int ipdbg_max_tools_from_data_register_length(uint8_t data_register_length)
{
    int max_tools = 1;
    data_register_length -= 10; /* 8 bit payload, 1 xoff-flag, 1 valid-flag; remaining bits used to select tool*/
    while (data_register_length--)
        max_tools *= 2;
 
    /* last tool is used to reset JtagCDC and transfer "XON" to host*/
    return max_tools - 1;
}
 
static struct ipdbg_service *ipdbg_find_service(struct ipdbg_hub *hub, uint8_t tool)
{
    struct ipdbg_service *service;
    for (service = ipdbg_first_service ; service ; service = service->next) {
        if (service->hub == hub && service->tool == tool)
            break;
    }
    return service;
}
 
static void ipdbg_add_service(struct ipdbg_service *service)
{
    struct ipdbg_service *iservice;
    if (ipdbg_first_service) {
        for (iservice = ipdbg_first_service ; iservice->next; iservice = iservice->next)
            ;
        iservice->next = service;
    } else
        ipdbg_first_service = service;
}
 
static int ipdbg_create_service(struct ipdbg_hub *hub, uint8_t tool, struct ipdbg_service **service, uint16_t port)
{
    *service = calloc(1, sizeof(struct ipdbg_service));
    if (!*service) {
        LOG_ERROR("Out of memory");
        return ERROR_FAIL;
    }
 
    (*service)->hub = hub;
    (*service)->tool = tool;
    (*service)->port = port;
 
    return ERROR_OK;
}
 
static int ipdbg_remove_service(struct ipdbg_service *service)
{
    if (!ipdbg_first_service)
        return ERROR_FAIL;
 
    if (service == ipdbg_first_service) {
        ipdbg_first_service = ipdbg_first_service->next;
        return ERROR_OK;
    }
 
    for (struct ipdbg_service *iservice = ipdbg_first_service ; iservice->next ; iservice = iservice->next) {
        if (service == iservice->next) {
            iservice->next = service->next;
            return ERROR_OK;
        }
    }
    return ERROR_FAIL;
}
 
static struct ipdbg_hub *ipdbg_find_hub(struct jtag_tap *tap,
                uint32_t user_instruction, struct ipdbg_virtual_ir_info *virtual_ir)
{
    struct ipdbg_hub *hub = NULL;
    for (hub = ipdbg_first_hub ; hub ; hub = hub->next) {
        if (hub->tap == tap && hub->user_instruction == user_instruction) {
            if ((!virtual_ir && !hub->virtual_ir) ||
                 (virtual_ir && hub->virtual_ir &&
                  virtual_ir->instruction == hub->virtual_ir->instruction &&
                  virtual_ir->length == hub->virtual_ir->length &&
                  virtual_ir->value == hub->virtual_ir->value)) {
                break;
            }
        }
    }
    return hub;
}
 
static void ipdbg_add_hub(struct ipdbg_hub *hub)
{
    struct ipdbg_hub *ihub;
    if (ipdbg_first_hub) {
        for (ihub = ipdbg_first_hub ; ihub->next; ihub = ihub->next)
            ;
        ihub->next = hub;
    } else
        ipdbg_first_hub = hub;
}
 
static int ipdbg_create_hub(struct jtag_tap *tap, uint32_t user_instruction, uint8_t data_register_length,
                      struct ipdbg_virtual_ir_info *virtual_ir, struct ipdbg_hub **hub)
{
    *hub = NULL;
    struct ipdbg_hub *new_hub = calloc(1, sizeof(struct ipdbg_hub));
    if (!new_hub) {
        free(virtual_ir);
        LOG_ERROR("Out of memory");
        return ERROR_FAIL;
    }
 
    new_hub->max_tools = ipdbg_max_tools_from_data_register_length(data_register_length);
    new_hub->connections = calloc(new_hub->max_tools, sizeof(struct connection *));
    if (!new_hub->connections) {
        free(virtual_ir);
        free(new_hub);
        LOG_ERROR("Out of memory");
        return ERROR_FAIL;
    }
    new_hub->tap                  = tap;
    new_hub->user_instruction     = user_instruction;
    new_hub->data_register_length = data_register_length;
    new_hub->valid_mask           = BIT(data_register_length - 1);
    new_hub->xoff_mask            = BIT(data_register_length - 2);
    new_hub->tool_mask            = (new_hub->xoff_mask - 1) >> 8;
    new_hub->last_dn_tool         = new_hub->tool_mask;
    new_hub->virtual_ir           = virtual_ir;
 
    *hub = new_hub;
 
    return ERROR_OK;
}
 
static void ipdbg_free_hub(struct ipdbg_hub *hub)
{
    if (!hub)
        return;
    free(hub->connections);
    free(hub->virtual_ir);
    free(hub);
}
 
static int ipdbg_remove_hub(struct ipdbg_hub *hub)
{
    if (!ipdbg_first_hub)
        return ERROR_FAIL;
    if (hub == ipdbg_first_hub) {
        ipdbg_first_hub = ipdbg_first_hub->next;
        return ERROR_OK;
    }
 
    for (struct ipdbg_hub *ihub = ipdbg_first_hub ; ihub->next ; ihub = ihub->next) {
        if (hub == ihub->next) {
            ihub->next = hub->next;
            return ERROR_OK;
        }
    }
 
    return ERROR_FAIL;
}
 
static void ipdbg_init_scan_field(struct scan_field *fields, uint8_t *in_value, int num_bits, const uint8_t *out_value)
{
    fields->check_mask = NULL;
    fields->check_value = NULL;
    fields->in_value = in_value;
    fields->num_bits = num_bits;
    fields->out_value = out_value;
}
 
static int ipdbg_shift_instr(struct ipdbg_hub *hub, uint32_t instr)
{
    if (!hub)
        return ERROR_FAIL;
 
    struct jtag_tap *tap = hub->tap;
    if (!tap)
        return ERROR_FAIL;
 
    if (buf_get_u32(tap->cur_instr, 0, tap->ir_length) == instr) {
        /* there is already the requested instruction in the ir */
        return ERROR_OK;
    }
 
    uint8_t *ir_out_val = calloc(DIV_ROUND_UP(tap->ir_length, 8), 1);
    buf_set_u32(ir_out_val, 0, tap->ir_length, instr);
 
    struct scan_field fields;
    ipdbg_init_scan_field(&fields, NULL, tap->ir_length, ir_out_val);
    jtag_add_ir_scan(tap, &fields, TAP_IDLE);
    int retval = jtag_execute_queue();
 
    free(ir_out_val);
 
    return retval;
}
 
static int ipdbg_shift_vir(struct ipdbg_hub *hub)
{
    if (!hub)
        return ERROR_FAIL;
 
    if (!hub->virtual_ir)
        return ERROR_OK;
 
    int retval = ipdbg_shift_instr(hub, hub->virtual_ir->instruction);
    if (retval != ERROR_OK)
        return retval;
 
    struct jtag_tap *tap = hub->tap;
    if (!tap)
        return ERROR_FAIL;
 
    uint8_t *dr_out_val = calloc(DIV_ROUND_UP(hub->virtual_ir->length, 8), 1);
    buf_set_u32(dr_out_val, 0, hub->virtual_ir->length, hub->virtual_ir->value);
 
    struct scan_field fields;
    ipdbg_init_scan_field(&fields, NULL, hub->virtual_ir->length, dr_out_val);
    jtag_add_dr_scan(tap, 1, &fields, TAP_IDLE);
    retval = jtag_execute_queue();
 
    free(dr_out_val);
 
    return retval;
}
 
static int ipdbg_shift_data(struct ipdbg_hub *hub, uint32_t dn_data, uint32_t *up_data)
{
    if (!hub)
        return ERROR_FAIL;
 
    struct jtag_tap *tap = hub->tap;
    if (!tap)
        return ERROR_FAIL;
 
    uint8_t *dr_out_val = calloc(DIV_ROUND_UP(hub->data_register_length, 8), 1);
    buf_set_u32(dr_out_val, 0, hub->data_register_length, dn_data);
    uint8_t *dr_in_val = up_data ? calloc(DIV_ROUND_UP(hub->data_register_length, 8), 1) : NULL;
 
    struct scan_field fields;
    ipdbg_init_scan_field(&fields, dr_in_val, hub->data_register_length, dr_out_val);
    jtag_add_dr_scan(tap, 1, &fields, TAP_IDLE);
    int retval = jtag_execute_queue();
 
    if (up_data && retval == ERROR_OK)
        *up_data = buf_get_u32(dr_in_val, 0, hub->data_register_length);
 
    free(dr_out_val);
    free(dr_in_val);
 
    return retval;
}
 
static int ipdbg_distribute_data_from_hub(struct ipdbg_hub *hub, uint32_t up)
{
    const bool valid_up_data = up & hub->valid_mask;
    if (!valid_up_data)
        return ERROR_OK;
 
    const size_t tool = (up >> 8) & hub->tool_mask;
    if (tool == hub->tool_mask) {
        const uint8_t xon_cmd = up & 0x00ff;
        hub->dn_xoff &= ~xon_cmd;
        LOG_INFO("received xon cmd: %d\n", xon_cmd);
        return ERROR_OK;
    }
 
    struct connection *conn = hub->connections[tool];
    if (conn) {
        struct ipdbg_connection *connection = conn->priv;
        if (ipdbg_fifo_is_full(&connection->up_fifo)) {
            int retval = ipdbg_move_buffer_to_connection(conn, &connection->up_fifo);
            if (retval != ERROR_OK)
                return retval;
        }
        ipdbg_append_to_fifo(&connection->up_fifo, up);
    }
    return ERROR_OK;
}
 
static int ipdbg_jtag_transfer_byte(struct ipdbg_hub *hub, size_t tool, struct ipdbg_connection *connection)
{
    uint32_t dn = hub->valid_mask | ((tool & hub->tool_mask) << 8) |
                (0x00fful & ipdbg_get_from_fifo(&connection->dn_fifo));
    uint32_t up = 0;
    int ret = ipdbg_shift_data(hub, dn, &up);
    if (ret != ERROR_OK)
        return ret;
 
    ret = ipdbg_distribute_data_from_hub(hub, up);
    if (ret != ERROR_OK)
        return ret;
 
    if ((up & hub->xoff_mask) && (hub->last_dn_tool != hub->max_tools)) {
        hub->dn_xoff |= BIT(hub->last_dn_tool);
        LOG_INFO("tool %d sent xoff", hub->last_dn_tool);
    }
 
    hub->last_dn_tool = tool;
 
    return ERROR_OK;
}
 
static int ipdbg_polling_callback(void *priv)
{
    struct ipdbg_hub *hub = priv;
 
    int ret = ipdbg_shift_vir(hub);
    if (ret != ERROR_OK)
        return ret;
 
    ret = ipdbg_shift_instr(hub, hub->user_instruction);
    if (ret != ERROR_OK)
        return ret;
 
    /* transfer dn buffers to jtag-hub */
    unsigned int num_transfers = 0;
    for (size_t tool = 0 ; tool < hub->max_tools ; ++tool) {
        struct connection *conn = hub->connections[tool];
        if (conn && conn->priv) {
            struct ipdbg_connection *connection = conn->priv;
            while (((hub->dn_xoff & BIT(tool)) == 0) && !ipdbg_fifo_is_empty(&connection->dn_fifo)) {
                ret = ipdbg_jtag_transfer_byte(hub, tool, connection);
                if (ret != ERROR_OK)
                    return ret;
                ++num_transfers;
            }
        }
    }
 
    /* some transfers to get data from jtag-hub in case there is no dn data */
    while (num_transfers++ < hub->max_tools) {
        uint32_t dn = 0;
        uint32_t up = 0;
 
        int retval = ipdbg_shift_data(hub, dn, &up);
        if (retval != ERROR_OK)
            return ret;
 
        retval = ipdbg_distribute_data_from_hub(hub, up);
        if (retval != ERROR_OK)
            return ret;
    }
 
    /* write from up fifos to sockets */
    for (size_t tool = 0 ; tool < hub->max_tools ; ++tool) {
        struct connection *conn = hub->connections[tool];
        if (conn && conn->priv) {
            struct ipdbg_connection *connection = conn->priv;
            int retval = ipdbg_move_buffer_to_connection(conn, &connection->up_fifo);
            if (retval != ERROR_OK)
                return retval;
        }
    }
 
    return ERROR_OK;
}
 
static int ipdbg_start_polling(struct ipdbg_service *service, struct connection *connection)
{
    struct ipdbg_hub *hub = service->hub;
    hub->connections[service->tool] = connection;
    hub->active_connections++;
    if (hub->active_connections > 1) {
        /* hub is already initialized */
        return ERROR_OK;
    }
 
    const uint32_t reset_hub = hub->valid_mask | ((hub->max_tools) << 8);
 
    int ret = ipdbg_shift_vir(hub);
    if (ret != ERROR_OK)
        return ret;
 
    ret = ipdbg_shift_instr(hub, hub->user_instruction);
    if (ret != ERROR_OK)
        return ret;
 
    ret = ipdbg_shift_data(hub, reset_hub, NULL);
    hub->last_dn_tool = hub->tool_mask;
    hub->dn_xoff = 0;
    if (ret != ERROR_OK)
        return ret;
 
    LOG_INFO("IPDBG start_polling");
 
    const int time_ms = 20;
    const int periodic = 1;
    return target_register_timer_callback(ipdbg_polling_callback, time_ms, periodic, hub);
}
 
static int ipdbg_stop_polling(struct ipdbg_service *service)
{
    struct ipdbg_hub *hub = service->hub;
    hub->connections[service->tool] = NULL;
    hub->active_connections--;
    if (hub->active_connections == 0) {
        LOG_INFO("IPDBG stop_polling");
 
        return target_unregister_timer_callback(ipdbg_polling_callback, hub);
    }
 
    return ERROR_OK;
}
 
static int ipdbg_on_new_connection(struct connection *connection)
{
    struct ipdbg_service *service = connection->service->priv;
    connection->priv = &service->connection;
    /* initialize ipdbg connection information */
    ipdbg_init_fifo(&service->connection.up_fifo);
    ipdbg_init_fifo(&service->connection.dn_fifo);
 
    int retval = ipdbg_start_polling(service, connection);
    if (retval != ERROR_OK) {
        LOG_ERROR("BUG: ipdbg_start_polling failed");
        return retval;
    }
 
    struct ipdbg_connection *conn = connection->priv;
    conn->closed = false;
 
    LOG_INFO("New IPDBG Connection");
 
    return ERROR_OK;
}
 
static int ipdbg_on_connection_input(struct connection *connection)
{
    struct ipdbg_connection *conn = connection->priv;
    struct ipdbg_fifo *fifo = &conn->dn_fifo;
 
    if (ipdbg_fifo_is_full(fifo))
        return ERROR_OK;
 
    ipdbg_zero_rd_idx(fifo);
    int bytes_read = connection_read(connection, fifo->buffer + fifo->count, IPDBG_BUFFER_SIZE - fifo->count);
    if (bytes_read <= 0) {
        if (bytes_read < 0)
            LOG_ERROR("error during read: %s", strerror(errno));
        return ERROR_SERVER_REMOTE_CLOSED;
    }
 
    fifo->count += bytes_read;
 
    return ERROR_OK;
}
 
static int ipdbg_on_connection_closed(struct connection *connection)
{
    struct ipdbg_connection *conn = connection->priv;
    conn->closed = true;
    LOG_INFO("Closed IPDBG Connection");
 
    return ipdbg_stop_polling(connection->service->priv);
}
 
static const struct service_driver ipdbg_service_driver = {
    .name = "ipdbg",
    .new_connection_during_keep_alive_handler = NULL,
    .new_connection_handler = ipdbg_on_new_connection,
    .input_handler = ipdbg_on_connection_input,
    .connection_closed_handler = ipdbg_on_connection_closed,
    .keep_client_alive_handler = NULL,
};
 
static int ipdbg_start(uint16_t port, struct jtag_tap *tap, uint32_t user_instruction,
                    uint8_t data_register_length, struct ipdbg_virtual_ir_info *virtual_ir, uint8_t tool)
{
    LOG_INFO("starting ipdbg service on port %d for tool %d", port, tool);
 
    struct ipdbg_hub *hub = ipdbg_find_hub(tap, user_instruction, virtual_ir);
    if (hub) {
        free(virtual_ir);
        if (hub->data_register_length != data_register_length) {
            LOG_DEBUG("hub must have the same data_register_length for all tools");
            return ERROR_FAIL;
        }
    } else {
        int retval = ipdbg_create_hub(tap, user_instruction, data_register_length, virtual_ir, &hub);
        if (retval != ERROR_OK) {
            free(virtual_ir);
            return retval;
        }
    }
 
    struct ipdbg_service *service = NULL;
    int retval = ipdbg_create_service(hub, tool, &service, port);
 
    if (retval != ERROR_OK || !service) {
        if (hub->active_services == 0 && hub->active_connections == 0)
            ipdbg_free_hub(hub);
        return ERROR_FAIL;
    }
 
    char port_str_buffer[IPDBG_TCP_PORT_STR_MAX_LENGTH];
    snprintf(port_str_buffer, IPDBG_TCP_PORT_STR_MAX_LENGTH, "%u", port);
    retval = add_service(&ipdbg_service_driver, port_str_buffer, 1, service);
    if (retval == ERROR_OK) {
        ipdbg_add_service(service);
        if (hub->active_services == 0 && hub->active_connections == 0)
            ipdbg_add_hub(hub);
        hub->active_services++;
    } else {
        if (hub->active_services == 0 && hub->active_connections == 0)
            ipdbg_free_hub(hub);
        free(service);
    }
 
    return retval;
}
 
static int ipdbg_stop(struct jtag_tap *tap, uint32_t user_instruction,
            struct ipdbg_virtual_ir_info *virtual_ir, uint8_t tool)
{
    struct ipdbg_hub *hub = ipdbg_find_hub(tap, user_instruction, virtual_ir);
    free(virtual_ir);
    if (!hub)
        return ERROR_FAIL;
 
    struct ipdbg_service *service = ipdbg_find_service(hub, tool);
    if (!service)
        return ERROR_FAIL;
 
    int retval = ipdbg_remove_service(service);
    if (retval != ERROR_OK) {
        LOG_ERROR("BUG: ipdbg_remove_service failed");
        return retval;
    }
 
    char port_str_buffer[IPDBG_TCP_PORT_STR_MAX_LENGTH];
    snprintf(port_str_buffer, IPDBG_TCP_PORT_STR_MAX_LENGTH, "%u", service->port);
    retval = remove_service("ipdbg", port_str_buffer);
    /* The ipdbg_service structure is freed by server.c:remove_service().
       There the "priv" pointer is freed.*/
    if (retval != ERROR_OK) {
        LOG_ERROR("BUG: remove_service failed");
        return retval;
    }
    hub->active_services--;
    if (hub->active_connections == 0 && hub->active_services == 0) {
        retval = ipdbg_remove_hub(hub);
        if (retval != ERROR_OK) {
            LOG_ERROR("BUG: ipdbg_remove_hub failed");
            return retval;
        }
        ipdbg_free_hub(hub);
    }
    return ERROR_OK;
}
 
COMMAND_HANDLER(handle_ipdbg_command)
{
    struct jtag_tap *tap = NULL;
    uint16_t port = 4242;
    uint8_t tool = 1;
    uint32_t user_instruction = 0x00;
    uint8_t data_register_length = IPDBG_MAX_DR_LENGTH;
    bool start = true;
    bool hub_configured = false;
    bool has_virtual_ir = false;
    uint32_t virtual_ir_instruction = 0x00e;
    uint32_t virtual_ir_length = 5;
    uint32_t virtual_ir_value = 0x11;
    struct ipdbg_virtual_ir_info *virtual_ir = NULL;
 
    if ((CMD_ARGC < IPDBG_MIN_NUM_OF_OPTIONS) || (CMD_ARGC > IPDBG_MAX_NUM_OF_OPTIONS))
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    for (unsigned int i = 0; i < CMD_ARGC; ++i) {
        if (strcmp(CMD_ARGV[i], "-tap") == 0) {
            if (i + 1 >= CMD_ARGC || CMD_ARGV[i + 1][0] == '-') {
                command_print(CMD, "no TAP given");
                return ERROR_FAIL;
            }
            tap = jtag_tap_by_string(CMD_ARGV[i + 1]);
            if (!tap) {
                command_print(CMD, "Tap %s unknown", CMD_ARGV[i + 1]);
                return ERROR_FAIL;
            }
            ++i;
        } else if (strcmp(CMD_ARGV[i], "-hub") == 0) {
            COMMAND_PARSE_ADDITIONAL_NUMBER(u32, i, user_instruction, "ir_value to select hub");
            hub_configured = true;
            COMMAND_PARSE_OPTIONAL_NUMBER(u8, i, data_register_length);
            if (data_register_length < IPDBG_MIN_DR_LENGTH ||
                data_register_length > IPDBG_MAX_DR_LENGTH) {
                command_print(CMD, "length of \"user\"-data register must be at least %d and at most %d.",
                            IPDBG_MIN_DR_LENGTH, IPDBG_MAX_DR_LENGTH);
                return ERROR_FAIL;
            }
        } else if (strcmp(CMD_ARGV[i], "-vir") == 0) {
            COMMAND_PARSE_OPTIONAL_NUMBER(u32, i, virtual_ir_value);
            COMMAND_PARSE_OPTIONAL_NUMBER(u32, i, virtual_ir_length);
            COMMAND_PARSE_OPTIONAL_NUMBER(u32, i, virtual_ir_instruction);
            has_virtual_ir = true;
        } else if (strcmp(CMD_ARGV[i], "-port") == 0) {
            COMMAND_PARSE_ADDITIONAL_NUMBER(u16, i, port, "port number");
        } else if (strcmp(CMD_ARGV[i], "-tool") == 0) {
            COMMAND_PARSE_ADDITIONAL_NUMBER(u8, i, tool, "tool");
        } else if (strcmp(CMD_ARGV[i], "-stop") == 0) {
            start = false;
        } else if (strcmp(CMD_ARGV[i], "-start") == 0) {
            start = true;
        } else {
            command_print(CMD, "Unknown argument: %s", CMD_ARGV[i]);
            return ERROR_FAIL;
        }
    }
 
    if (!tap) {
        command_print(CMD, "no valid tap selected");
        return ERROR_FAIL;
    }
 
    if (!hub_configured) {
        command_print(CMD, "hub not configured correctly");
        return ERROR_FAIL;
    }
 
    if (tool >= ipdbg_max_tools_from_data_register_length(data_register_length)) {
        command_print(CMD, "Tool: %d is invalid", tool);
        return ERROR_FAIL;
    }
 
    if (has_virtual_ir) {
        virtual_ir = calloc(1, sizeof(struct ipdbg_virtual_ir_info));
        if (!virtual_ir) {
            LOG_ERROR("Out of memory");
            return ERROR_FAIL;
        }
        virtual_ir->instruction = virtual_ir_instruction;
        virtual_ir->length      = virtual_ir_length;
        virtual_ir->value       = virtual_ir_value;
    }
 
    if (start)
        return ipdbg_start(port, tap, user_instruction, data_register_length, virtual_ir, tool);
    else
        return ipdbg_stop(tap, user_instruction, virtual_ir, tool);
}
 
static const struct command_registration ipdbg_command_handlers[] = {
    {
        .name = "ipdbg",
        .handler = handle_ipdbg_command,
        .mode = COMMAND_EXEC,
        .help = "Starts or stops an IPDBG JTAG-Host server.",
        .usage = "[-start|-stop] -tap device.tap -hub ir_value [dr_length]"
                 " [-port number] [-tool number] [-vir [vir_value [length [instr_code]]]]",
    },
    COMMAND_REGISTRATION_DONE
};
 
int ipdbg_register_commands(struct command_context *cmd_ctx)
{
    return register_commands(cmd_ctx, NULL, ipdbg_command_handlers);
}