fsm_coe.c

/******************************************************************************
 *
 *  $Id$
 *
 *  Copyright (C) 2006-2008  Florian Pose, Ingenieurgemeinschaft IgH
 *
 *  This file is part of the IgH EtherCAT Master.
 *
 *  The IgH EtherCAT Master is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License version 2, as
 *  published by the Free Software Foundation.
 *
 *  The IgH EtherCAT Master is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
 *  Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with the IgH EtherCAT Master; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 *  ---
 *
 *  The license mentioned above concerns the source code only. Using the
 *  EtherCAT technology and brand is only permitted in compliance with the
 *  industrial property and similar rights of Beckhoff Automation GmbH.
 *
 *****************************************************************************/

/**
   \file
   EtherCAT CoE state machines.
*/

/*****************************************************************************/

#include "globals.h"
#include "master.h"
#include "mailbox.h"
#include "fsm_coe.h"

/*****************************************************************************/

/** Maximum time in ms to wait for responses when reading out the dictionary.
 */
#define EC_FSM_COE_DICT_TIMEOUT 1000

/** CoE download request header size.
 */
#define EC_COE_DOWN_REQ_HEADER_SIZE 10

/** CoE download segment request header size.
 */
#define EC_COE_DOWN_SEG_REQ_HEADER_SIZE 3

/** Minimum size of download segment.
 */
#define EC_COE_DOWN_SEG_MIN_DATA_SIZE 7

/** Enable debug output for CoE retries.
 */
#define DEBUG_RETRIES 0

/** Enable warning output if transfers take too long.
 */
#define DEBUG_LONG 0

/*****************************************************************************/

void ec_fsm_coe_dict_start(ec_fsm_coe_t *);
void ec_fsm_coe_dict_request(ec_fsm_coe_t *);
void ec_fsm_coe_dict_check(ec_fsm_coe_t *);
void ec_fsm_coe_dict_response(ec_fsm_coe_t *);
void ec_fsm_coe_dict_desc_request(ec_fsm_coe_t *);
void ec_fsm_coe_dict_desc_check(ec_fsm_coe_t *);
void ec_fsm_coe_dict_desc_response(ec_fsm_coe_t *);
void ec_fsm_coe_dict_entry_request(ec_fsm_coe_t *);
void ec_fsm_coe_dict_entry_check(ec_fsm_coe_t *);
void ec_fsm_coe_dict_entry_response(ec_fsm_coe_t *);

void ec_fsm_coe_down_start(ec_fsm_coe_t *);
void ec_fsm_coe_down_request(ec_fsm_coe_t *);
void ec_fsm_coe_down_check(ec_fsm_coe_t *);
void ec_fsm_coe_down_response(ec_fsm_coe_t *);
void ec_fsm_coe_down_seg_check(ec_fsm_coe_t *);
void ec_fsm_coe_down_seg_response(ec_fsm_coe_t *);

void ec_fsm_coe_up_start(ec_fsm_coe_t *);
void ec_fsm_coe_up_request(ec_fsm_coe_t *);
void ec_fsm_coe_up_check(ec_fsm_coe_t *);
void ec_fsm_coe_up_response(ec_fsm_coe_t *);
void ec_fsm_coe_up_seg_request(ec_fsm_coe_t *);
void ec_fsm_coe_up_seg_check(ec_fsm_coe_t *);
void ec_fsm_coe_up_seg_response(ec_fsm_coe_t *);

void ec_fsm_coe_end(ec_fsm_coe_t *);
void ec_fsm_coe_error(ec_fsm_coe_t *);

/*****************************************************************************/

/**
   SDO abort messages.
   The "abort SDO transfer request" supplies an abort code,
   which can be translated to clear text. This table does
   the mapping of the codes and messages.
*/

const ec_code_msg_t sdo_abort_messages[] = {
    {0x05030000, "Toggle bit not changed"},
    {0x05040000, "SDO protocol timeout"},
    {0x05040001, "Client/Server command specifier not valid or unknown"},
    {0x05040005, "Out of memory"},
    {0x06010000, "Unsupported access to an object"},
    {0x06010001, "Attempt to read a write-only object"},
    {0x06010002, "Attempt to write a read-only object"},
    {0x06020000, "This object does not exist in the object directory"},
    {0x06040041, "The object cannot be mapped into the PDO"},
    {0x06040042, "The number and length of the objects to be mapped would"
     " exceed the PDO length"},
    {0x06040043, "General parameter incompatibility reason"},
    {0x06040047, "Gerneral internal incompatibility in device"},
    {0x06060000, "Access failure due to a hardware error"},
    {0x06070010, "Data type does not match, length of service parameter does"
     " not match"},
    {0x06070012, "Data type does not match, length of service parameter too"
     " high"},
    {0x06070013, "Data type does not match, length of service parameter too"
     " low"},
    {0x06090011, "Subindex does not exist"},
    {0x06090030, "Value range of parameter exceeded"},
    {0x06090031, "Value of parameter written too high"},
    {0x06090032, "Value of parameter written too low"},
    {0x06090036, "Maximum value is less than minimum value"},
    {0x08000000, "General error"},
    {0x08000020, "Data cannot be transferred or stored to the application"},
    {0x08000021, "Data cannot be transferred or stored to the application"
     " because of local control"},
    {0x08000022, "Data cannot be transferred or stored to the application"
     " because of the present device state"},
    {0x08000023, "Object dictionary dynamic generation fails or no object"
     " dictionary is present"},
    {}
};

/*****************************************************************************/

/** Outputs an SDO abort message.
 */
void ec_canopen_abort_msg(const ec_slave_t *slave, uint32_t abort_code)
{
    const ec_code_msg_t *abort_msg;

    for (abort_msg = sdo_abort_messages; abort_msg->code; abort_msg++) {
        if (abort_msg->code == abort_code) {
            EC_SLAVE_ERR(slave, "SDO abort message 0x%08X: \"%s\".\n",
                   abort_msg->code, abort_msg->message);
            return;
        }
    }

    EC_SLAVE_ERR(slave, "Unknown SDO abort code 0x%08X.\n", abort_code);
}

/*****************************************************************************/

/**
   Constructor.
*/

void ec_fsm_coe_init(ec_fsm_coe_t *fsm, /**< finite state machine */
                     ec_datagram_t *datagram /**< datagram */
                     )
{
    fsm->state = NULL;
    fsm->datagram = datagram;
}

/*****************************************************************************/

/**
   Destructor.
*/

void ec_fsm_coe_clear(ec_fsm_coe_t *fsm /**< finite state machine */)
{
}

/*****************************************************************************/

/**
   Starts reading a slaves' SDO dictionary.
*/

void ec_fsm_coe_dictionary(ec_fsm_coe_t *fsm, /**< finite state machine */
                           ec_slave_t *slave /**< EtherCAT slave */
                           )
{
    fsm->slave = slave;
    fsm->state = ec_fsm_coe_dict_start;
}

/*****************************************************************************/

/**
   Starts to transfer an SDO to/from a slave.
*/

void ec_fsm_coe_transfer(
        ec_fsm_coe_t *fsm, /**< State machine. */
        ec_slave_t *slave, /**< EtherCAT slave. */
        ec_sdo_request_t *request /**< SDO request. */
        )
{
    fsm->slave = slave;
    fsm->request = request;
    if (request->dir == EC_DIR_OUTPUT)
        fsm->state = ec_fsm_coe_down_start;
    else
        fsm->state = ec_fsm_coe_up_start;
}

/*****************************************************************************/

/**
   Executes the current state of the state machine.
   \return false, if state machine has terminated
*/

int ec_fsm_coe_exec(ec_fsm_coe_t *fsm /**< finite state machine */)
{
    fsm->state(fsm);

    return fsm->state != ec_fsm_coe_end && fsm->state != ec_fsm_coe_error;
}

/*****************************************************************************/

/**
   Returns, if the state machine terminated with success.
   \return non-zero if successful.
*/

int ec_fsm_coe_success(ec_fsm_coe_t *fsm /**< Finite state machine */)
{
    return fsm->state == ec_fsm_coe_end;
}

/*****************************************************************************/

/** Check if the received data are a CoE emergency request.
 *
 * If the check is positive, the emergency request is output.
 *
 * \return The data were an emergency request.
 */
int ec_fsm_coe_check_emergency(
        ec_fsm_coe_t *fsm, /**< Finite state machine */
        const uint8_t *data, /**< CoE mailbox data. */
        size_t size /**< CoE mailbox data size. */
        )
{
    if (size < 2 || ((EC_READ_U16(data) >> 12) & 0x0F) != 0x01)
        return 0;

    if (size < 10) {
        EC_SLAVE_WARN(fsm->slave, "Received incomplete CoE Emergency"
                " request:\n");
        ec_print_data(data, size);
        return 1;
    }

    EC_SLAVE_WARN(fsm->slave, "CoE Emergency Request received:\n"
            "Error code 0x%04X, Error register 0x%02X, data:\n",
            EC_READ_U16(data + 2), EC_READ_U8(data + 4));
    ec_print_data(data + 5, 5);
    return 1;
}

/******************************************************************************
 *  CoE dictionary state machine
 *****************************************************************************/

/**
   CoE state: DICT START.
*/

void ec_fsm_coe_dict_start(ec_fsm_coe_t *fsm /**< finite state machine */)
{
    ec_datagram_t *datagram = fsm->datagram;
    ec_slave_t *slave = fsm->slave;
    uint8_t *data;

    if (!(slave->sii.mailbox_protocols & EC_MBOX_COE)) {
        EC_SLAVE_ERR(slave, "Slave does not support CoE!\n");
        fsm->state = ec_fsm_coe_error;
        return;
    }

    if (slave->sii.has_general && !slave->sii.coe_details.enable_sdo_info) {
        EC_SLAVE_ERR(slave, "Slave does not support"
                " SDO information service!\n");
        fsm->state = ec_fsm_coe_error;
        return;
    }

    data = ec_slave_mbox_prepare_send(slave, datagram, 0x03, 8);
    if (IS_ERR(data)) {
        fsm->state = ec_fsm_coe_error;
        return;
    }

    EC_WRITE_U16(data, 0x8 << 12); // SDO information
    EC_WRITE_U8 (data + 2, 0x01); // Get OD List Request
    EC_WRITE_U8 (data + 3, 0x00);
    EC_WRITE_U16(data + 4, 0x0000);
    EC_WRITE_U16(data + 6, 0x0001); // deliver all SDOs!

    fsm->retries = EC_FSM_RETRIES;
    fsm->state = ec_fsm_coe_dict_request;
}

/*****************************************************************************/

/**
   CoE state: DICT REQUEST.
   \todo Timeout behavior
*/

void ec_fsm_coe_dict_request(ec_fsm_coe_t *fsm /**< finite state machine */)
{
    ec_datagram_t *datagram = fsm->datagram;
    ec_slave_t *slave = fsm->slave;

    if (datagram->state == EC_DATAGRAM_TIMED_OUT && fsm->retries--)
        return; // FIXME: request again?

    if (datagram->state != EC_DATAGRAM_RECEIVED) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave, "Failed to receive CoE dictionary"
                " request datagram: ");
        ec_datagram_print_state(datagram);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave, "Reception of CoE dictionary request failed: ");
        ec_datagram_print_wc_error(datagram);
        return;
    }

    fsm->jiffies_start = datagram->jiffies_sent;

    ec_slave_mbox_prepare_check(slave, datagram); // can not fail.
    fsm->retries = EC_FSM_RETRIES;
    fsm->state = ec_fsm_coe_dict_check;
}

/*****************************************************************************/

/**
   CoE state: DICT CHECK.
*/

void ec_fsm_coe_dict_check(ec_fsm_coe_t *fsm /**< finite state machine */)
{
    ec_datagram_t *datagram = fsm->datagram;
    ec_slave_t *slave = fsm->slave;

    if (datagram->state == EC_DATAGRAM_TIMED_OUT && fsm->retries--)
        return;

    if (datagram->state != EC_DATAGRAM_RECEIVED) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave, "Failed to receive CoE mailbox check datagram: ");
        ec_datagram_print_state(datagram);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave,"Reception of CoE mailbox check"
                " datagram failed: ");
        ec_datagram_print_wc_error(datagram);
        return;
    }

    if (!ec_slave_mbox_check(datagram)) {
        unsigned long diff_ms =
            (datagram->jiffies_received - fsm->jiffies_start) * 1000 / HZ;
        if (diff_ms >= EC_FSM_COE_DICT_TIMEOUT) {
            fsm->state = ec_fsm_coe_error;
            EC_SLAVE_ERR(slave, "Timeout while waiting for"
                    " SDO dictionary list response.\n");
            return;
        }

        ec_slave_mbox_prepare_check(slave, datagram); // can not fail.
        fsm->retries = EC_FSM_RETRIES;
        return;
    }

    // Fetch response
    ec_slave_mbox_prepare_fetch(slave, datagram); // can not fail.
    fsm->retries = EC_FSM_RETRIES;
    fsm->state = ec_fsm_coe_dict_response;
}

/*****************************************************************************/

/**
   CoE state: DICT RESPONSE.
   \todo Timeout behavior
*/

void ec_fsm_coe_dict_response(ec_fsm_coe_t *fsm /**< finite state machine */)
{
    ec_datagram_t *datagram = fsm->datagram;
    ec_slave_t *slave = fsm->slave;
    uint8_t *data, mbox_prot;
    size_t rec_size;
    unsigned int sdo_count, i;
    uint16_t sdo_index, fragments_left;
    ec_sdo_t *sdo;
    bool first_segment;
    size_t index_list_offset;

    if (datagram->state == EC_DATAGRAM_TIMED_OUT && fsm->retries--)
        return; // FIXME: request again?

    if (datagram->state != EC_DATAGRAM_RECEIVED) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave, "Failed to receive CoE dictionary"
                " response datagram: ");
        ec_datagram_print_state(datagram);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave, "Reception of CoE dictionary response failed: ");
        ec_datagram_print_wc_error(datagram);
        return;
    }

    data = ec_slave_mbox_fetch(slave, datagram, &mbox_prot, &rec_size);
    if (IS_ERR(data)) {
        fsm->state = ec_fsm_coe_error;
        return;
    }

    if (mbox_prot != 0x03) { // CoE
        EC_SLAVE_ERR(slave, "Received mailbox protocol 0x%02X as response.\n",
                mbox_prot);
        fsm->state = ec_fsm_coe_error;
        return;
    }

    if (ec_fsm_coe_check_emergency(fsm, data, rec_size)) {
        // check for CoE response again
        ec_slave_mbox_prepare_check(slave, datagram); // can not fail.
        fsm->retries = EC_FSM_RETRIES;
        fsm->state = ec_fsm_coe_dict_check;
        return;
    }

    if (rec_size < 3) {
        EC_SLAVE_ERR(slave, "Received corrupted SDO dictionary response"
                " (size %zu).\n", rec_size);
        fsm->state = ec_fsm_coe_error;
        return;
    }

    if (EC_READ_U16(data) >> 12 == 0x8 && // SDO information
        (EC_READ_U8(data + 2) & 0x7F) == 0x07) { // error response
        EC_SLAVE_ERR(slave, "SDO information error response!\n");
        if (rec_size < 10) {
            EC_SLAVE_ERR(slave, "Incomplete SDO information"
                    " error response:\n");
            ec_print_data(data, rec_size);
        } else {
            ec_canopen_abort_msg(slave, EC_READ_U32(data + 6));
        }
        fsm->state = ec_fsm_coe_error;
        return;
    }

    if (EC_READ_U16(data) >> 12 != 0x8 || // SDO information
        (EC_READ_U8 (data + 2) & 0x7F) != 0x02) { // Get OD List response
        if (fsm->slave->master->debug_level) {
            EC_SLAVE_DBG(slave, 1, "Invalid SDO list response!"
                    " Retrying...\n");
            ec_print_data(data, rec_size);
        }
        ec_slave_mbox_prepare_check(slave, datagram); // can not fail.
        fsm->retries = EC_FSM_RETRIES;
        fsm->state = ec_fsm_coe_dict_check;
        return;
    }

    first_segment = list_empty(&slave->sdo_dictionary) ? true : false;
    index_list_offset = first_segment ? 8 : 6;

    if (rec_size < index_list_offset || rec_size % 2) {
        EC_SLAVE_ERR(slave, "Invalid data size %zu!\n", rec_size);
        ec_print_data(data, rec_size);
        fsm->state = ec_fsm_coe_error;
        return;
    }

    sdo_count = (rec_size - index_list_offset) / 2;

    for (i = 0; i < sdo_count; i++) {
        sdo_index = EC_READ_U16(data + index_list_offset + i * 2);
        if (!sdo_index) {
            EC_SLAVE_DBG(slave, 1, "SDO dictionary contains index 0x0000.\n");
            continue;
        }

        if (!(sdo = (ec_sdo_t *) kmalloc(sizeof(ec_sdo_t), GFP_KERNEL))) {
            EC_SLAVE_ERR(slave, "Failed to allocate memory for SDO!\n");
            fsm->state = ec_fsm_coe_error;
            return;
        }

        ec_sdo_init(sdo, slave, sdo_index);
        list_add_tail(&sdo->list, &slave->sdo_dictionary);
    }

    fragments_left = EC_READ_U16(data + 4);
    if (fragments_left) {
        EC_SLAVE_DBG(slave, 1, "SDO list fragments left: %u\n",
                fragments_left);
    }

    if (EC_READ_U8(data + 2) & 0x80 || fragments_left) {
        // more messages waiting. check again.
        fsm->jiffies_start = datagram->jiffies_sent;
        ec_slave_mbox_prepare_check(slave, datagram); // can not fail.
        fsm->retries = EC_FSM_RETRIES;
        fsm->state = ec_fsm_coe_dict_check;
        return;
    }

    if (list_empty(&slave->sdo_dictionary)) {
        // no SDOs in dictionary. finished.
        fsm->state = ec_fsm_coe_end; // success
        return;
    }

    // fetch SDO descriptions
    fsm->sdo = list_entry(slave->sdo_dictionary.next, ec_sdo_t, list);

    data = ec_slave_mbox_prepare_send(slave, datagram, 0x03, 8);
    if (IS_ERR(data)) {
        fsm->state = ec_fsm_coe_error;
        return;
    }

    EC_WRITE_U16(data, 0x8 << 12); // SDO information
    EC_WRITE_U8 (data + 2, 0x03); // Get object description request
    EC_WRITE_U8 (data + 3, 0x00);
    EC_WRITE_U16(data + 4, 0x0000);
    EC_WRITE_U16(data + 6, fsm->sdo->index); // SDO index

    fsm->retries = EC_FSM_RETRIES;
    fsm->state = ec_fsm_coe_dict_desc_request;
}

/*****************************************************************************/

/**
   CoE state: DICT DESC REQUEST.
   \todo Timeout behavior
*/

void ec_fsm_coe_dict_desc_request(ec_fsm_coe_t *fsm /**< finite state machine */)
{
    ec_datagram_t *datagram = fsm->datagram;
    ec_slave_t *slave = fsm->slave;

    if (datagram->state == EC_DATAGRAM_TIMED_OUT && fsm->retries--)
        return; // FIXME: check for response first?

    if (datagram->state != EC_DATAGRAM_RECEIVED) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave, "Failed to receive CoE SDO"
                " description request datagram: ");
        ec_datagram_print_state(datagram);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave, "Reception of CoE SDO description"
                " request failed: ");
        ec_datagram_print_wc_error(datagram);
        return;
    }

    fsm->jiffies_start = datagram->jiffies_sent;

    ec_slave_mbox_prepare_check(slave, datagram); // can not fail.
    fsm->retries = EC_FSM_RETRIES;
    fsm->state = ec_fsm_coe_dict_desc_check;
}

/*****************************************************************************/

/**
   CoE state: DICT DESC CHECK.
*/

void ec_fsm_coe_dict_desc_check(ec_fsm_coe_t *fsm /**< finite state machine */)
{
    ec_datagram_t *datagram = fsm->datagram;
    ec_slave_t *slave = fsm->slave;

    if (datagram->state == EC_DATAGRAM_TIMED_OUT && fsm->retries--)
        return;

    if (datagram->state != EC_DATAGRAM_RECEIVED) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave, "Failed to receive CoE mailbox check datagram: ");
        ec_datagram_print_state(datagram);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave, "Reception of CoE mailbox check"
                " datagram failed: ");
        ec_datagram_print_wc_error(datagram);
        return;
    }

    if (!ec_slave_mbox_check(datagram)) {
        unsigned long diff_ms =
            (datagram->jiffies_received - fsm->jiffies_start) * 1000 / HZ;
        if (diff_ms >= EC_FSM_COE_DICT_TIMEOUT) {
            fsm->state = ec_fsm_coe_error;
            EC_SLAVE_ERR(slave, "Timeout while waiting for"
                    " SDO 0x%04x object description response.\n",
                    fsm->sdo->index);
            return;
        }

        ec_slave_mbox_prepare_check(slave, datagram); // can not fail.
        fsm->retries = EC_FSM_RETRIES;
        return;
    }

    // Fetch response
    ec_slave_mbox_prepare_fetch(slave, datagram); // can not fail.
    fsm->retries = EC_FSM_RETRIES;
    fsm->state = ec_fsm_coe_dict_desc_response;
}

/*****************************************************************************/

/**
   CoE state: DICT DESC RESPONSE.
   \todo Timeout behavior
*/

void ec_fsm_coe_dict_desc_response(ec_fsm_coe_t *fsm
                                   /**< finite state machine */)
{
    ec_datagram_t *datagram = fsm->datagram;
    ec_slave_t *slave = fsm->slave;
    ec_sdo_t *sdo = fsm->sdo;
    uint8_t *data, mbox_prot;
    size_t rec_size, name_size;

    if (datagram->state == EC_DATAGRAM_TIMED_OUT && fsm->retries--)
        return; // FIXME: request again?

    if (datagram->state != EC_DATAGRAM_RECEIVED) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave, "Failed to receive CoE SDO description"
                " response datagram: ");
        ec_datagram_print_state(datagram);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave, "Reception of CoE SDO description"
                " response failed: ");
        ec_datagram_print_wc_error(datagram);
        return;
    }

    data = ec_slave_mbox_fetch(slave, datagram, &mbox_prot, &rec_size);
    if (IS_ERR(data)) {
        fsm->state = ec_fsm_coe_error;
        return;
    }

    if (mbox_prot != 0x03) { // CoE
        EC_SLAVE_ERR(slave, "Received mailbox protocol 0x%02X as response.\n",
                mbox_prot);
        fsm->state = ec_fsm_coe_error;
        return;
    }

    if (ec_fsm_coe_check_emergency(fsm, data, rec_size)) {
        // check for CoE response again
        ec_slave_mbox_prepare_check(slave, datagram); // can not fail.
        fsm->retries = EC_FSM_RETRIES;
        fsm->state = ec_fsm_coe_dict_desc_check;
        return;
    }

    if (rec_size < 3) {
        EC_SLAVE_ERR(slave, "Received corrupted SDO description response"
                " (size %zu).\n", rec_size);
        fsm->state = ec_fsm_coe_error;
        return;
    }

    if (EC_READ_U16(data) >> 12 == 0x8 && // SDO information
        (EC_READ_U8 (data + 2) & 0x7F) == 0x07) { // error response
        EC_SLAVE_ERR(slave, "SDO information error response while"
                " fetching SDO 0x%04X!\n", sdo->index);
        ec_canopen_abort_msg(slave, EC_READ_U32(data + 6));
        fsm->state = ec_fsm_coe_error;
        return;
    }

    if (rec_size < 8) {
        EC_SLAVE_ERR(slave, "Received corrupted SDO"
                " description response (size %zu).\n", rec_size);
        fsm->state = ec_fsm_coe_error;
        return;
    }

    if (EC_READ_U16(data) >> 12 != 0x8 || // SDO information
        (EC_READ_U8 (data + 2) & 0x7F) != 0x04 || // Object desc. response
        EC_READ_U16(data + 6) != sdo->index) { // SDO index
        if (fsm->slave->master->debug_level) {
            EC_SLAVE_DBG(slave, 1, "Invalid object description response while"
                    " fetching SDO 0x%04X!\n", sdo->index);
            ec_print_data(data, rec_size);
        }
        // check for CoE response again
        ec_slave_mbox_prepare_check(slave, datagram); // can not fail.
        fsm->retries = EC_FSM_RETRIES;
        fsm->state = ec_fsm_coe_dict_desc_check;
        return;
    }

    if (rec_size < 12) {
        EC_SLAVE_ERR(slave, "Invalid data size!\n");
        ec_print_data(data, rec_size);
        fsm->state = ec_fsm_coe_error;
        return;
    }

    sdo->max_subindex = EC_READ_U8(data + 10);
    sdo->object_code = EC_READ_U8(data + 11);

    name_size = rec_size - 12;
    if (name_size) {
        if (!(sdo->name = kmalloc(name_size + 1, GFP_KERNEL))) {
            EC_SLAVE_ERR(slave, "Failed to allocate SDO name!\n");
            fsm->state = ec_fsm_coe_error;
            return;
        }

        memcpy(sdo->name, data + 12, name_size);
        sdo->name[name_size] = 0;
    }

    if (EC_READ_U8(data + 2) & 0x80) {
        EC_SLAVE_ERR(slave, "Fragment follows (not implemented)!\n");
        fsm->state = ec_fsm_coe_error;
        return;
    }

    // start fetching entries

    fsm->subindex = 0;

    data = ec_slave_mbox_prepare_send(slave, datagram, 0x03, 10);
    if (IS_ERR(data)) {
        fsm->state = ec_fsm_coe_error;
        return;
    }

    EC_WRITE_U16(data, 0x8 << 12); // SDO information
    EC_WRITE_U8 (data + 2, 0x05); // Get entry description request
    EC_WRITE_U8 (data + 3, 0x00);
    EC_WRITE_U16(data + 4, 0x0000);
    EC_WRITE_U16(data + 6, sdo->index); // SDO index
    EC_WRITE_U8 (data + 8, fsm->subindex); // SDO subindex
    EC_WRITE_U8 (data + 9, 0x01); // value info (access rights only)

    fsm->retries = EC_FSM_RETRIES;
    fsm->state = ec_fsm_coe_dict_entry_request;
}

/*****************************************************************************/

/**
   CoE state: DICT ENTRY REQUEST.
   \todo Timeout behavior
*/

void ec_fsm_coe_dict_entry_request(ec_fsm_coe_t *fsm
                                   /**< finite state machine */)
{
    ec_datagram_t *datagram = fsm->datagram;
    ec_slave_t *slave = fsm->slave;

    if (datagram->state == EC_DATAGRAM_TIMED_OUT && fsm->retries--)
        return; // FIXME: check for response first?

    if (datagram->state != EC_DATAGRAM_RECEIVED) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave, "Failed to receive CoE SDO entry"
                " request datagram: ");
        ec_datagram_print_state(datagram);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave, "Reception of CoE SDO entry request failed: ");
        ec_datagram_print_wc_error(datagram);
        return;
    }

    fsm->jiffies_start = datagram->jiffies_sent;

    ec_slave_mbox_prepare_check(slave, datagram); // can not fail
    fsm->retries = EC_FSM_RETRIES;
    fsm->state = ec_fsm_coe_dict_entry_check;
}

/*****************************************************************************/

/**
   CoE state: DICT ENTRY CHECK.
*/

void ec_fsm_coe_dict_entry_check(ec_fsm_coe_t *fsm
                                 /**< finite state machine */)
{
    ec_datagram_t *datagram = fsm->datagram;
    ec_slave_t *slave = fsm->slave;

    if (datagram->state == EC_DATAGRAM_TIMED_OUT && fsm->retries--)
        return;

    if (datagram->state != EC_DATAGRAM_RECEIVED) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave, "Failed to receive CoE mailbox check datagram: ");
        ec_datagram_print_state(datagram);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave, "Reception of CoE mailbox check"
                " datagram failed: ");
        ec_datagram_print_wc_error(datagram);
        return;
    }

    if (!ec_slave_mbox_check(datagram)) {
        unsigned long diff_ms =
            (datagram->jiffies_received - fsm->jiffies_start) * 1000 / HZ;
        if (diff_ms >= EC_FSM_COE_DICT_TIMEOUT) {
            fsm->state = ec_fsm_coe_error;
            EC_SLAVE_ERR(slave, "Timeout while waiting for"
                    " SDO entry 0x%04x:%x description response.\n",
                    fsm->sdo->index, fsm->subindex);
            return;
        }

        ec_slave_mbox_prepare_check(slave, datagram); // can not fail.
        fsm->retries = EC_FSM_RETRIES;
        return;
    }

    // Fetch response
    ec_slave_mbox_prepare_fetch(slave, datagram); // can not fail.
    fsm->retries = EC_FSM_RETRIES;
    fsm->state = ec_fsm_coe_dict_entry_response;
}

/*****************************************************************************/

/**
   CoE state: DICT ENTRY RESPONSE.
   \todo Timeout behavior
*/

void ec_fsm_coe_dict_entry_response(ec_fsm_coe_t *fsm
                                    /**< finite state machine */)
{
    ec_datagram_t *datagram = fsm->datagram;
    ec_slave_t *slave = fsm->slave;
    ec_sdo_t *sdo = fsm->sdo;
    uint8_t *data, mbox_prot;
    size_t rec_size, data_size;
    ec_sdo_entry_t *entry;
    u16 word;

    if (datagram->state == EC_DATAGRAM_TIMED_OUT && fsm->retries--)
        return; // FIXME: request again?

    if (datagram->state != EC_DATAGRAM_RECEIVED) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave, "Failed to receive CoE SDO"
                " description response datagram: ");
        ec_datagram_print_state(datagram);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->state = ec_fsm_coe_error;
        EC_SLAVE_ERR(slave, "Reception of CoE SDO description"
                " response failed: ");
        ec_datagram_print_wc_error(datagram);
        return;
    }

    data = ec_slave_mbox_fetch(slave, datagram, &mbox_prot, &rec_size);
    if (IS_ERR(data)) {
        fsm->state = ec_fsm_coe_error;
        return;
    }

    if (mbox_prot != 0x03) { // CoE
        EC_SLAVE_ERR(slave, "Received mailbox protocol"
                " 0x%02X as response.\n", mbox_prot);
        fsm->state = ec_fsm_coe_error;
        return;
    }

    if (ec_fsm_coe_check_emergency(fsm, data, rec_size)) {
        // check for CoE response again
        ec_slave_mbox_prepare_check(slave, datagram); // can not fail.
        fsm->retries = EC_FSM_RETRIES;
        fsm->state = ec_fsm_coe_dict_entry_check;
        return;
    }

    if (rec_size < 3) {
        EC_SLAVE_ERR(slave, "Received corrupted SDO entry"
                " description response (size %zu).\n", rec_size);
        fsm->state = ec_fsm_coe_error;
        return;
    }

    if (EC_READ_U16(data) >> 12 == 0x8 && // SDO information
        (EC_READ_U8 (data + 2) & 0x7F) == 0x07) { // error response
        EC_SLAVE_ERR(slave, "SDO information error response while"
               " fetching SDO entry 0x%04X:%02X!\n",
               sdo->index, fsm->subindex);
        ec_canopen_abort_msg(slave, EC_READ_U32(data + 6));
        fsm->state = ec_fsm_coe_error;
        return;
    }

    if (rec_size < 9) {
        EC_SLAVE_ERR(slave, "Received corrupted SDO entry"
                " description response (size %zu).\n", rec_size);
        fsm->state = ec_fsm_coe_error;
        return;
    }

    if (EC_READ_U16(data) >> 12 != 0x8 || // SDO information
        (EC_READ_U8(data + 2) & 0x7F) != 0x06 || // Entry desc. response
        EC_READ_U16(data + 6) != sdo->index || // SDO index
        EC_READ_U8(data + 8) != fsm->subindex) { // SDO subindex
        if (fsm->slave->master->debug_level) {
            EC_SLAVE_DBG(slave, 1, "Invalid entry description response while"
                    " fetching SDO entry 0x%04X:%02X!\n",
                    sdo->index, fsm->subindex);
            ec_print_data(data, rec_size);
        }
        // check for CoE response again
        ec_slave_mbox_prepare_check(slave, datagram); // can not fail.
        fsm->retries = EC_FSM_RETRIES;
        fsm->state = ec_fsm_coe_dict_entry_check;
        return;
    }

    if (rec_size < 16) {
        EC_SLAVE_ERR(slave, "Invalid data size %zu!\n", rec_size);
        ec_print_data(data, rec_size);
        fsm->state = ec_fsm_coe_error;
        return;
    }

    data_size = rec_size - 16;