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 <pld/pld.h>
 
#include "ipdbg.h"
 
#define IPDBG_BUFFER_SIZE 16384
#define IPDBG_MIN_NUM_OF_CREATE_OPTIONS 3
#define IPDBG_MAX_NUM_OF_CREATE_OPTIONS 10
#define IPDBG_NUM_OF_START_OPTIONS 4
#define IPDBG_NUM_OF_STOP_OPTIONS 2
#define IPDBG_NUM_OF_QUEUE_OPTIONS 2
#define IPDBG_MIN_DR_LENGTH 11
#define IPDBG_MAX_DR_LENGTH 13
#define IPDBG_TCP_PORT_STR_MAX_LENGTH 6
#define IPDBG_SCRATCH_MEMORY_SIZE 1024
 
/* 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_scratch_memory {
    uint8_t *dr_out_vals;
    uint8_t *dr_in_vals;
    uint8_t *vir_out_val;
    struct scan_field *fields;
};
 
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;
    char *name;
    size_t using_queue_size;
    struct ipdbg_hub *next;
    struct jtag_tap *tap;
    struct connection **connections;
    uint8_t data_register_length;
    uint8_t dn_xoff;
    uint8_t flow_control_enabled;
    struct ipdbg_virtual_ir_info *virtual_ir;
    struct ipdbg_hub_scratch_memory scratch_memory;
};
 
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_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_free_hub(struct ipdbg_hub *hub)
{
    if (!hub)
        return;
    free(hub->connections);
    free(hub->virtual_ir);
    free(hub->name);
    free(hub->scratch_memory.dr_out_vals);
    free(hub->scratch_memory.dr_in_vals);
    free(hub->scratch_memory.fields);
    free(hub->scratch_memory.vir_out_val);
    free(hub);
}
 
static struct ipdbg_hub *ipdbg_allocate_hub(uint8_t data_register_length, struct ipdbg_virtual_ir_info *virtual_ir,
                                            const char *name)
{
    struct ipdbg_hub *new_hub = calloc(1, sizeof(struct ipdbg_hub));
    if (!new_hub) {
        LOG_ERROR("Out of memory");
        return NULL;
    }
 
    new_hub->name = strdup(name);
    if (!new_hub->name) {
        free(new_hub);
        LOG_ERROR("Out of memory");
        return NULL;
    }
 
    const size_t dreg_buffer_size = DIV_ROUND_UP(data_register_length, 8);
    uint32_t max_tools = ipdbg_max_tools_from_data_register_length(data_register_length);
 
    new_hub->scratch_memory.dr_out_vals = calloc(IPDBG_SCRATCH_MEMORY_SIZE, dreg_buffer_size);
    new_hub->scratch_memory.dr_in_vals = calloc(IPDBG_SCRATCH_MEMORY_SIZE, dreg_buffer_size);
    new_hub->scratch_memory.fields = calloc(IPDBG_SCRATCH_MEMORY_SIZE, sizeof(struct scan_field));
    new_hub->connections = calloc(max_tools, sizeof(struct connection *));
 
    if (virtual_ir)
        new_hub->scratch_memory.vir_out_val = calloc(1, DIV_ROUND_UP(virtual_ir->length, 8));
 
    if (!new_hub->scratch_memory.dr_out_vals || !new_hub->scratch_memory.dr_in_vals ||
        !new_hub->scratch_memory.fields || (virtual_ir && !new_hub->scratch_memory.vir_out_val) ||
        !new_hub->connections) {
        ipdbg_free_hub(new_hub);
        LOG_ERROR("Out of memory");
        return NULL;
    }
 
    return new_hub;
}
 
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);
    if (!ir_out_val) {
        LOG_ERROR("Out of memory");
        return ERROR_FAIL;
    }
    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;
 
    ipdbg_init_scan_field(hub->scratch_memory.fields, NULL,
        hub->virtual_ir->length, hub->scratch_memory.vir_out_val);
    jtag_add_dr_scan(tap, 1, hub->scratch_memory.fields, TAP_IDLE);
    retval = jtag_execute_queue();
 
    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;
 
    buf_set_u32(hub->scratch_memory.dr_out_vals, 0, hub->data_register_length, dn_data);
 
    ipdbg_init_scan_field(hub->scratch_memory.fields, hub->scratch_memory.dr_in_vals,
                        hub->data_register_length, hub->scratch_memory.dr_out_vals);
    jtag_add_dr_scan(tap, 1, hub->scratch_memory.fields, TAP_IDLE);
    int retval = jtag_execute_queue();
 
    if (up_data && retval == ERROR_OK)
        *up_data = buf_get_u32(hub->scratch_memory.dr_in_vals, 0, hub->data_register_length);
 
    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 void ipdbg_check_for_xoff(struct ipdbg_hub *hub, size_t tool,
                                uint32_t rx_data)
{
    if ((rx_data & 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;
}
 
static int ipdbg_shift_empty_data(struct ipdbg_hub *hub)
{
    if (!hub)
        return ERROR_FAIL;
 
    struct jtag_tap *tap = hub->tap;
    if (!tap)
        return ERROR_FAIL;
 
    const size_t dreg_buffer_size = DIV_ROUND_UP(hub->data_register_length, 8);
    memset(hub->scratch_memory.dr_out_vals, 0, dreg_buffer_size);
    for (size_t i = 0; i < hub->using_queue_size; ++i) {
        ipdbg_init_scan_field(hub->scratch_memory.fields + i,
                                hub->scratch_memory.dr_in_vals + i * dreg_buffer_size,
                                hub->data_register_length,
                                hub->scratch_memory.dr_out_vals);
        jtag_add_dr_scan(tap, 1, hub->scratch_memory.fields + i, TAP_IDLE);
    }
 
    int retval = jtag_execute_queue();
 
    if (retval == ERROR_OK) {
        uint32_t up_data;
        for (size_t i = 0; i < hub->using_queue_size; ++i) {
            up_data = buf_get_u32(hub->scratch_memory.dr_in_vals +
                                    i * dreg_buffer_size, 0,
                                    hub->data_register_length);
            int rv = ipdbg_distribute_data_from_hub(hub, up_data);
            if (rv != ERROR_OK)
                retval = rv;
 
            if (i == 0) {
                /* check if xoff sent is only needed on the first transfer which
                   may contain the xoff of the prev down transfer.
                */
                ipdbg_check_for_xoff(hub, hub->max_tools, up_data);
            }
        }
    }
 
    return retval;
}
 
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;
 
    ipdbg_check_for_xoff(hub, tool, up);
 
    return ERROR_OK;
}
 
static int ipdbg_jtag_transfer_bytes(struct ipdbg_hub *hub,
            size_t tool, struct ipdbg_connection *connection)
{
    if (!hub)
        return ERROR_FAIL;
 
    struct jtag_tap *tap = hub->tap;
    if (!tap)
        return ERROR_FAIL;
 
    const size_t dreg_buffer_size = DIV_ROUND_UP(hub->data_register_length, 8);
    size_t num_tx = (connection->dn_fifo.count < hub->using_queue_size) ?
        connection->dn_fifo.count : hub->using_queue_size;
 
    for (size_t i = 0; i < num_tx; ++i) {
        uint32_t dn_data = hub->valid_mask | ((tool & hub->tool_mask) << 8) |
            (0x00fful & ipdbg_get_from_fifo(&connection->dn_fifo));
        buf_set_u32(hub->scratch_memory.dr_out_vals + i * dreg_buffer_size, 0,
                    hub->data_register_length, dn_data);
 
        ipdbg_init_scan_field(hub->scratch_memory.fields + i,
                                hub->scratch_memory.dr_in_vals +
                                    i * dreg_buffer_size,
                                hub->data_register_length,
                                hub->scratch_memory.dr_out_vals +
                                    i * dreg_buffer_size);
        jtag_add_dr_scan(tap, 1, hub->scratch_memory.fields + i, TAP_IDLE);
    }
 
    int retval = jtag_execute_queue();
 
    if (retval == ERROR_OK) {
        uint32_t up_data;
        for (size_t i = 0; i < num_tx; ++i) {
            up_data = buf_get_u32(hub->scratch_memory.dr_in_vals +
                                    i * dreg_buffer_size,
                                    0, hub->data_register_length);
            int rv = ipdbg_distribute_data_from_hub(hub, up_data);
            if (rv != ERROR_OK)
                retval = rv;
            if (i == 0) {
                /* check if xoff sent is only needed on the first transfer which
                   may contain the xoff of the prev down transfer.
                   No checks for this channel because this function is only
                   called for channels without enabled flow control.
                */
                ipdbg_check_for_xoff(hub, tool, up_data);
            }
        }
    }
 
    return retval;
}
 
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 */
    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)) {
                if (hub->flow_control_enabled & BIT(tool))
                    ret = ipdbg_jtag_transfer_byte(hub, tool, connection);
                else
                    ret = ipdbg_jtag_transfer_bytes(hub, tool, connection);
                if (ret != ERROR_OK)
                    return ret;
            }
        }
    }
 
    /* some transfers to get data from jtag-hub in case there is no dn data */
    ret = ipdbg_shift_empty_data(hub);
    if (ret != 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_get_flow_control_info_from_hub(struct ipdbg_hub *hub)
{
    uint32_t up_data;
 
    /* on older implementations the flow_control_enable_word is not sent to us.
        so we don't know -> assume it's enabled on all channels */
    hub->flow_control_enabled = 0x7f;
 
    int ret = ipdbg_shift_data(hub, 0UL, &up_data);
    if (ret != ERROR_OK)
        return ret;
 
    const bool valid_up_data = up_data & hub->valid_mask;
    if (valid_up_data) {
        const size_t tool = (up_data >> 8) & hub->tool_mask;
        /* the first valid data from hub is flow_control_enable_word */
        if (tool == hub->tool_mask)
            hub->flow_control_enabled = up_data & 0x007f;
        else
            ipdbg_distribute_data_from_hub(hub, up_data);
    }
 
    LOG_INFO("Flow control enabled on IPDBG JTAG Hub: 0x%02x", hub->flow_control_enabled);
 
    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;
 
    ret = ipdbg_get_flow_control_info_from_hub(hub);
    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 struct ipdbg_hub *ipdbg_get_hub_by_name(const char *name)
{
    struct ipdbg_hub *hub = NULL;
    for (hub = ipdbg_first_hub; hub; hub = hub->next) {
        if (strcmp(hub->name, name) == 0)
            break;
    }
    return hub;
};
 
static int ipdbg_stop_service(struct ipdbg_service *service)
{
    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;
    }
    return ERROR_OK;
}
 
int ipdbg_server_free(void)
{
    int retval = ERROR_OK;
    for (struct ipdbg_hub *hub = ipdbg_first_hub; hub;) {
        for (uint8_t tool = 0; tool < hub->max_tools; ++tool) {
            struct ipdbg_service *service = ipdbg_find_service(hub, tool);
            if (service) {
                int new_retval = ipdbg_stop_service(service);
                if (new_retval != ERROR_OK)
                    retval = new_retval;
                hub->active_services--;
            }
        }
        struct ipdbg_hub *next_hub = hub->next;
        int new_retval = ipdbg_remove_hub(hub);
        if (new_retval != ERROR_OK)
            retval = new_retval;
        ipdbg_free_hub(hub);
        hub = next_hub;
    }
    return retval;
}
 
static int ipdbg_start(struct ipdbg_hub *hub, uint16_t port, uint8_t tool)
{
    LOG_INFO("starting ipdbg service on port %d for tool %d", port, tool);
 
    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) {
        free(service);
        return retval;
    }
    ipdbg_add_service(service);
    hub->active_services++;
    return ERROR_OK;
}
 
COMMAND_HANDLER(handle_ipdbg_start_command)
{
    struct ipdbg_hub *hub = CMD_DATA;
 
    uint16_t port = 4242;
    uint8_t tool = 1;
 
    if (CMD_ARGC > IPDBG_NUM_OF_START_OPTIONS)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    for (unsigned int i = 0; i < CMD_ARGC; ++i) {
        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 {
            command_print(CMD, "Unknown argument: %s", CMD_ARGV[i]);
            return ERROR_FAIL;
        }
    }
 
    return ipdbg_start(hub, port, tool);
}
 
static int ipdbg_stop(struct ipdbg_hub *hub, uint8_t tool)
{
    struct ipdbg_service *service = ipdbg_find_service(hub, tool);
    if (!service) {
        LOG_ERROR("No service for hub '%s'/tool %d found", hub->name, tool);
        return ERROR_FAIL;
    }
 
    int retval = ipdbg_stop_service(service);
    hub->active_services--;
 
    LOG_INFO("stopped ipdbg service for tool %d", tool);
    return retval;
}
 
COMMAND_HANDLER(handle_ipdbg_stop_command)
{
    struct ipdbg_hub *hub = CMD_DATA;
 
    uint8_t tool = 1;
 
    if (CMD_ARGC > IPDBG_NUM_OF_STOP_OPTIONS)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    for (unsigned int i = 0; i < CMD_ARGC; ++i) {
        if (strcmp(CMD_ARGV[i], "-tool") == 0) {
            COMMAND_PARSE_ADDITIONAL_NUMBER(u8, i, tool, "tool");
        } else {
            command_print(CMD, "Unknown argument: %s", CMD_ARGV[i]);
            return ERROR_FAIL;
        }
    }
 
    return ipdbg_stop(hub, tool);
}
 
static const struct command_registration ipdbg_hostserver_subcommand_handlers[] = {
    {
        .name = "start",
        .mode = COMMAND_EXEC,
        .handler = handle_ipdbg_start_command,
        .help = "Starts a IPDBG Host server.",
        .usage = "-tool number -port port"
    }, {
        .name = "stop",
        .mode = COMMAND_EXEC,
        .handler = handle_ipdbg_stop_command,
        .help = "Stops a IPDBG Host server.",
        .usage = "-tool number"
    },
    COMMAND_REGISTRATION_DONE
};
 
static COMMAND_HELPER(ipdbg_config_queuing, struct ipdbg_hub *hub, unsigned int size)
{
    if (!hub)
        return ERROR_FAIL;
 
    if (hub->active_connections) {
        command_print(CMD, "Configuration change not allowed when hub has active connections");
        return ERROR_FAIL;
    }
 
    if (size == 0 || size > IPDBG_SCRATCH_MEMORY_SIZE) {
        command_print(CMD, "queuing size out of range! Must be 0 < size <= %d", IPDBG_SCRATCH_MEMORY_SIZE);
        return ERROR_COMMAND_ARGUMENT_INVALID;
    }
 
    hub->using_queue_size = size;
    return ERROR_OK;
}
 
COMMAND_HANDLER(handle_ipdbg_cfg_queuing_command)
{
    struct ipdbg_hub *hub = CMD_DATA;
 
    unsigned int size;
 
    if (CMD_ARGC != IPDBG_NUM_OF_QUEUE_OPTIONS)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    for (unsigned int i = 0; i < CMD_ARGC; ++i) {
        if (strcmp(CMD_ARGV[i], "-size") == 0) {
            COMMAND_PARSE_ADDITIONAL_NUMBER(uint, i, size, "size");
        } else {
            command_print(CMD, "Unknown argument: %s", CMD_ARGV[i]);
            return ERROR_FAIL;
        }
    }
 
    return CALL_COMMAND_HANDLER(ipdbg_config_queuing, hub, size);
}
 
static const struct command_registration ipdbg_hub_subcommand_handlers[] = {
    {
        .name = "ipdbg",
        .mode = COMMAND_EXEC,
        .help = "IPDBG Hub commands.",
        .usage = "",
        .chain = ipdbg_hostserver_subcommand_handlers
    },
    {
        .name = "queuing",
        .handler = handle_ipdbg_cfg_queuing_command,
        .mode = COMMAND_ANY,
        .help = "configures queuing between IPDBG Host and Hub.",
        .usage = "-size size",
    },
    COMMAND_REGISTRATION_DONE
};
 
static int ipdbg_register_hub_command(struct ipdbg_hub *hub, struct command_invocation *cmd)
{
    Jim_Interp *interp = CMD_CTX->interp;
 
    /* does this command exist? */
    Jim_Cmd *jcmd = Jim_GetCommand(interp, Jim_NewStringObj(interp, hub->name, -1), JIM_NONE);
    if (jcmd) {
        LOG_ERROR("cannot create Hub because a command with name '%s' already exists", hub->name);
        return ERROR_FAIL;
    }
 
    const struct command_registration obj_commands[] = {
        {
            .name = hub->name,
            .mode = COMMAND_EXEC,
            .help = "IPDBG Hub command group.",
            .usage = "",
            .chain = ipdbg_hub_subcommand_handlers
        },
        COMMAND_REGISTRATION_DONE
    };
 
    return register_commands_with_data(CMD_CTX, NULL, obj_commands, 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, const char *name, struct command_invocation *cmd)
{
    struct ipdbg_hub *new_hub = ipdbg_allocate_hub(data_register_length, virtual_ir, name);
    if (!new_hub)
        return ERROR_FAIL;
 
    if (virtual_ir)
        buf_set_u32(new_hub->scratch_memory.vir_out_val, 0, virtual_ir->length, virtual_ir->value);
    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;
    new_hub->max_tools            = ipdbg_max_tools_from_data_register_length(data_register_length);
    new_hub->using_queue_size     = IPDBG_SCRATCH_MEMORY_SIZE;
 
    int retval = ipdbg_register_hub_command(new_hub, cmd);
    if (retval != ERROR_OK) {
        LOG_ERROR("Creating hub failed");
        ipdbg_free_hub(new_hub);
        return ERROR_FAIL;
    }
 
    ipdbg_add_hub(new_hub);
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(handle_ipdbg_create_hub_command)
{
    struct jtag_tap *tap = NULL;
    uint32_t user_instruction = 0x00;
    uint8_t data_register_length = IPDBG_MAX_DR_LENGTH;
    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;
    int user_num = 1;
    bool hub_configured = false;
 
    if (CMD_ARGC < IPDBG_MIN_NUM_OF_CREATE_OPTIONS || CMD_ARGC > IPDBG_MAX_NUM_OF_CREATE_OPTIONS)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    const char *hub_name = CMD_ARGV[0];
 
    for (unsigned int i = 1; 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 name 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], "-ir") == 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], "-pld") == 0) {
            ++i;
            if (i >= CMD_ARGC || CMD_ARGV[i][0] == '-')
                return ERROR_COMMAND_SYNTAX_ERROR;
            struct pld_device *device = get_pld_device_by_name_or_numstr(CMD_ARGV[i]);
            if (!device || !device->driver) {
                command_print(CMD, "pld device '#%s' is out of bounds or unknown", CMD_ARGV[i]);
                return ERROR_FAIL;
            }
            COMMAND_PARSE_OPTIONAL_NUMBER(int, i, user_num);
            struct pld_ipdbg_hub pld_hub;
            struct pld_driver *driver = device->driver;
            if (!driver->get_ipdbg_hub) {
                command_print(CMD, "pld driver has no ipdbg support");
                return ERROR_FAIL;
            }
            if (driver->get_ipdbg_hub(user_num, device, &pld_hub) != ERROR_OK) {
                command_print(CMD, "unable to retrieve hub from pld driver");
                return ERROR_FAIL;
            }
            if (!pld_hub.tap) {
                command_print(CMD, "no tap received from pld driver");
                return ERROR_FAIL;
            }
            hub_configured = true;
            user_instruction = pld_hub.user_ir_code;
            tap = pld_hub.tap;
 
        } 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 {
            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 (ipdbg_get_hub_by_name(hub_name)) {
        LOG_ERROR("IPDBG hub with name '%s' already exists", hub_name);
        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 (ipdbg_find_hub(tap, user_instruction, virtual_ir)) {
        LOG_ERROR("IPDBG hub for given TAP and user-instruction already exists");
        free(virtual_ir);
        return ERROR_FAIL;
    }
 
    int retval = ipdbg_create_hub(tap, user_instruction, data_register_length, virtual_ir, hub_name, cmd);
    if (retval != ERROR_OK)
        free(virtual_ir);
 
    return retval;
}
 
static const struct command_registration ipdbg_config_command_handlers[] = {
    {
        .name = "create-hub",
        .mode = COMMAND_ANY,
        .handler = handle_ipdbg_create_hub_command,
        .help = "create a IPDBG Hub",
        .usage = "name.ipdbghub (-tap device.tap -ir ir_value [dr_length] |"
            " -pld name.pld [user]) [-vir [vir_value [length [instr_code]]]]",
    },
    COMMAND_REGISTRATION_DONE
};
 
static const struct command_registration ipdbg_command_handlers[] = {
    {
        .name = "ipdbg",
        .mode = COMMAND_ANY,
        .help = "IPDBG Hub/Host commands.",
        .usage = "",
        .chain = ipdbg_config_command_handlers,
    },
    COMMAND_REGISTRATION_DONE
};
 
int ipdbg_register_commands(struct command_context *cmd_ctx)
{
    return register_commands(cmd_ctx, NULL, ipdbg_command_handlers);
}