/******************************************************************************
 *
 *  $Id$
 *
 *  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 slave state machines.
*/

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

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

#include "fsm_slave_scan.h"

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

void ec_fsm_slave_scan_state_start(ec_fsm_slave_scan_t *);
void ec_fsm_slave_scan_state_address(ec_fsm_slave_scan_t *);
void ec_fsm_slave_scan_state_state(ec_fsm_slave_scan_t *);
void ec_fsm_slave_scan_state_base(ec_fsm_slave_scan_t *);
void ec_fsm_slave_scan_state_dc_cap(ec_fsm_slave_scan_t *);
void ec_fsm_slave_scan_state_dc_times(ec_fsm_slave_scan_t *);
void ec_fsm_slave_scan_state_datalink(ec_fsm_slave_scan_t *);
void ec_fsm_slave_scan_state_sii_size(ec_fsm_slave_scan_t *);
void ec_fsm_slave_scan_state_sii_data(ec_fsm_slave_scan_t *);
void ec_fsm_slave_scan_state_preop(ec_fsm_slave_scan_t *);
void ec_fsm_slave_scan_state_sync(ec_fsm_slave_scan_t *);
void ec_fsm_slave_scan_state_pdos(ec_fsm_slave_scan_t *);

void ec_fsm_slave_scan_state_end(ec_fsm_slave_scan_t *);
void ec_fsm_slave_scan_state_error(ec_fsm_slave_scan_t *);

void ec_fsm_slave_scan_enter_datalink(ec_fsm_slave_scan_t *);
void ec_fsm_slave_scan_enter_preop(ec_fsm_slave_scan_t *);
void ec_fsm_slave_scan_enter_pdos(ec_fsm_slave_scan_t *);

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

/** Constructor.
 */
void ec_fsm_slave_scan_init(
        ec_fsm_slave_scan_t *fsm, /**< Slave scanning state machine. */
        ec_datagram_t *datagram, /**< Datagram to use. */
        ec_fsm_slave_config_t *fsm_slave_config, /**< Slave configuration
                                                  state machine to use. */
        ec_fsm_pdo_t *fsm_pdo /**< PDO configuration machine to use. */
        )
{
    fsm->datagram = datagram;
    fsm->fsm_slave_config = fsm_slave_config;
    fsm->fsm_pdo = fsm_pdo;

    // init sub state machines
    ec_fsm_sii_init(&fsm->fsm_sii, fsm->datagram);
}

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

/** Destructor.
 */
void ec_fsm_slave_scan_clear(ec_fsm_slave_scan_t *fsm /**< slave state machine */)
{
    // clear sub state machines
    ec_fsm_sii_clear(&fsm->fsm_sii);
}

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

/**
 * Start slave scan state machine.
 */

void ec_fsm_slave_scan_start(
        ec_fsm_slave_scan_t *fsm, /**< slave state machine */
        ec_slave_t *slave /**< slave to configure */
        )
{
    fsm->slave = slave;
    fsm->state = ec_fsm_slave_scan_state_start;
}

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

/**
   \return false, if state machine has terminated
*/

int ec_fsm_slave_scan_running(const ec_fsm_slave_scan_t *fsm /**< slave state machine */)
{
    return fsm->state != ec_fsm_slave_scan_state_end
        && fsm->state != ec_fsm_slave_scan_state_error;
}

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

/**
   Executes the current state of the state machine.
   If the state machine's datagram is not sent or received yet, the execution
   of the state machine is delayed to the next cycle.
   \return false, if state machine has terminated
*/

int ec_fsm_slave_scan_exec(ec_fsm_slave_scan_t *fsm /**< slave state machine */)
{
    if (fsm->datagram->state == EC_DATAGRAM_SENT
        || fsm->datagram->state == EC_DATAGRAM_QUEUED) {
        // datagram was not sent or received yet.
        return ec_fsm_slave_scan_running(fsm);
    }

    fsm->state(fsm);
    return ec_fsm_slave_scan_running(fsm);
}

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

/**
   \return true, if the state machine terminated gracefully
*/

int ec_fsm_slave_scan_success(const ec_fsm_slave_scan_t *fsm /**< slave state machine */)
{
    return fsm->state == ec_fsm_slave_scan_state_end;
}

/******************************************************************************
 *  slave scan state machine
 *****************************************************************************/

/**
   Slave scan state: START.
   First state of the slave state machine. Writes the station address to the
   slave, according to its ring position.
*/

void ec_fsm_slave_scan_state_start(ec_fsm_slave_scan_t *fsm /**< slave state machine */)
{
    // write station address
    ec_datagram_apwr(fsm->datagram, fsm->slave->ring_position, 0x0010, 2);
    EC_WRITE_U16(fsm->datagram->data, fsm->slave->station_address);
    fsm->retries = EC_FSM_RETRIES;
    fsm->state = ec_fsm_slave_scan_state_address;
}

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

/**
   Slave scan state: ADDRESS.
*/

void ec_fsm_slave_scan_state_address(ec_fsm_slave_scan_t *fsm /**< slave state machine */)
{
    ec_datagram_t *datagram = fsm->datagram;

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

    if (datagram->state != EC_DATAGRAM_RECEIVED) {
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_ERR("Failed to receive station address datagram for slave %u"
                " (datagram state %u)\n",
                fsm->slave->ring_position, datagram->state);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->slave->error_flag = 1;
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_ERR("Failed to write station address on slave %u: ",
               fsm->slave->ring_position);
        ec_datagram_print_wc_error(datagram);
        return;
    }

    // Read AL state
    ec_datagram_fprd(datagram, fsm->slave->station_address, 0x0130, 2);
    ec_datagram_zero(datagram);
    fsm->retries = EC_FSM_RETRIES;
    fsm->state = ec_fsm_slave_scan_state_state;
}

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

/**
   Slave scan state: STATE.
*/

void ec_fsm_slave_scan_state_state(
        ec_fsm_slave_scan_t *fsm /**< slave 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_slave_scan_state_error;
        EC_ERR("Failed to receive AL state datagram from slave %u"
                " (datagram state %u).\n",
               fsm->slave->ring_position, datagram->state);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->slave->error_flag = 1;
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_ERR("Failed to read AL state of slave %u: ",
               fsm->slave->ring_position);
        ec_datagram_print_wc_error(datagram);
        return;
    }

    slave->current_state = EC_READ_U8(datagram->data);
    if (slave->current_state & EC_SLAVE_STATE_ACK_ERR) {
        char state_str[EC_STATE_STRING_SIZE];
        ec_state_string(slave->current_state, state_str, 0);
        EC_WARN("Slave %u has state error bit set (%s)!\n",
                slave->ring_position, state_str);
    }

    // read base data
    ec_datagram_fprd(datagram, fsm->slave->station_address, 0x0000, 12);
    ec_datagram_zero(datagram);
    fsm->retries = EC_FSM_RETRIES;
    fsm->state = ec_fsm_slave_scan_state_base;
}

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

/** Slave scan state: BASE.
 */
void ec_fsm_slave_scan_state_base(
        ec_fsm_slave_scan_t *fsm /**< slave state machine */
        )
{
    ec_datagram_t *datagram = fsm->datagram;
    ec_slave_t *slave = fsm->slave;
    u8 octet;
    int i;

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

    if (datagram->state != EC_DATAGRAM_RECEIVED) {
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_ERR("Failed to receive base data datagram for slave %u"
                " (datagram state %u).\n",
               slave->ring_position, datagram->state);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->slave->error_flag = 1;
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_ERR("Failed to read base data from slave %u: ",
               slave->ring_position);
        ec_datagram_print_wc_error(datagram);
        return;
    }

    slave->base_type       = EC_READ_U8 (datagram->data);
    slave->base_revision   = EC_READ_U8 (datagram->data + 1);
    slave->base_build      = EC_READ_U16(datagram->data + 2);

    slave->base_fmmu_count = EC_READ_U8 (datagram->data + 4);
    if (slave->base_fmmu_count > EC_MAX_FMMUS) {
        EC_WARN("Slave %u has more FMMUs (%u) than the master can"
                " handle (%u).\n", slave->ring_position,
                slave->base_fmmu_count, EC_MAX_FMMUS);
        slave->base_fmmu_count = EC_MAX_FMMUS;
    }

    slave->base_sync_count = EC_READ_U8 (datagram->data + 5);
    if (slave->base_sync_count > EC_MAX_SYNC_MANAGERS) {
        EC_WARN("Slave %u provides more sync managers (%u) than the master can"
                " handle (%u).\n", slave->ring_position,
                slave->base_sync_count, EC_MAX_SYNC_MANAGERS);
        slave->base_sync_count = EC_MAX_SYNC_MANAGERS;
    }

    octet = EC_READ_U8(datagram->data + 7);
    for (i = 0; i < EC_MAX_PORTS; i++) {
        slave->ports[i].desc = (octet >> (2 * i)) & 0x03;
    }
    
    octet = EC_READ_U8(datagram->data + 8);
    slave->base_fmmu_bit_operation = octet & 0x01;
    slave->base_dc_supported = (octet >> 2) & 0x01;
    slave->base_dc_range = ((octet >> 3) & 0x01) ? EC_DC_64 : EC_DC_32;

    if (slave->base_dc_supported) {
        // read DC capabilities
        ec_datagram_fprd(datagram, slave->station_address, 0x0910,
                slave->base_dc_range == EC_DC_64 ? 8 : 4);
        ec_datagram_zero(datagram);
        fsm->retries = EC_FSM_RETRIES;
        fsm->state = ec_fsm_slave_scan_state_dc_cap;
    } else {
        ec_fsm_slave_scan_enter_datalink(fsm);
    }
}

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

/**
   Slave scan state: DC CAPABILITIES.
*/

void ec_fsm_slave_scan_state_dc_cap(
        ec_fsm_slave_scan_t *fsm /**< slave 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_slave_scan_state_error;
        EC_ERR("Failed to receive system time datagram for slave %u"
                " (datagram state %u).\n",
               slave->ring_position, datagram->state);
        return;
    }

    if (datagram->working_counter == 1) {
        slave->has_dc_system_time = 1;
        if (slave->master->debug_level) {
            EC_DBG("Slave %u has the System Time register.\n",
                    slave->ring_position);
        }
    } else if (datagram->working_counter == 0) {
        if (slave->master->debug_level) {
            EC_DBG("Slave %u has no System Time register; delay "
                    "measurement only.\n", slave->ring_position);
        }
    } else {
        fsm->slave->error_flag = 1;
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_ERR("Failed to determine, if system time register is "
                "supported by slave %u: ", slave->ring_position);
        ec_datagram_print_wc_error(datagram);
        return;
    }

    // read DC port receive times
    ec_datagram_fprd(datagram, slave->station_address, 0x0900, 16);
    ec_datagram_zero(datagram);
    fsm->retries = EC_FSM_RETRIES;
    fsm->state = ec_fsm_slave_scan_state_dc_times;
}

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

/**
   Slave scan state: DC TIMES.
*/

void ec_fsm_slave_scan_state_dc_times(
        ec_fsm_slave_scan_t *fsm /**< slave state machine */
        )
{
    ec_datagram_t *datagram = fsm->datagram;
    ec_slave_t *slave = fsm->slave;
    int i;

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

    if (datagram->state != EC_DATAGRAM_RECEIVED) {
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_ERR("Failed to receive system time datagram for slave %u"
                " (datagram state %u).\n",
               slave->ring_position, datagram->state);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->slave->error_flag = 1;
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_ERR("Failed to get DC receive times of slave %u: ",
                slave->ring_position);
        ec_datagram_print_wc_error(datagram);
        return;
    }

    for (i = 0; i < EC_MAX_PORTS; i++) {
        slave->ports[i].receive_time = EC_READ_U32(datagram->data + 4 * i);
    }

    ec_fsm_slave_scan_enter_datalink(fsm);
}

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

/**
   Slave scan entry function: DATALINK.
*/

void ec_fsm_slave_scan_enter_datalink(
        ec_fsm_slave_scan_t *fsm /**< slave state machine */
        )
{
    ec_datagram_t *datagram = fsm->datagram;
    ec_slave_t *slave = fsm->slave;

    // read data link status
    ec_datagram_fprd(datagram, slave->station_address, 0x0110, 2);
    ec_datagram_zero(datagram);
    fsm->retries = EC_FSM_RETRIES;
    fsm->state = ec_fsm_slave_scan_state_datalink;
}

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

/**
   Slave scan state: DATALINK.
*/

void ec_fsm_slave_scan_state_datalink(ec_fsm_slave_scan_t *fsm /**< slave state machine */)
{
    ec_datagram_t *datagram = fsm->datagram;
    ec_slave_t *slave = fsm->slave;
    uint16_t dl_status;
    unsigned int i;

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

    if (datagram->state != EC_DATAGRAM_RECEIVED) {
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_ERR("Failed to receive DL status datagram from slave %u"
                " (datagram state %u).\n",
               slave->ring_position, datagram->state);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->slave->error_flag = 1;
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_ERR("Failed to read DL status from slave %u: ",
               slave->ring_position);
        ec_datagram_print_wc_error(datagram);
        return;
    }

    dl_status = EC_READ_U16(datagram->data);
    for (i = 0; i < EC_MAX_PORTS; i++) {
        slave->ports[i].link.link_up = dl_status & (1 << (4 + i)) ? 1 : 0;
        slave->ports[i].link.loop_closed = dl_status & (1 << (8 + i * 2)) ? 1 : 0;
        slave->ports[i].link.signal_detected = dl_status & (1 << (9 + i * 2)) ? 1 : 0;
    }

    // Start fetching SII size

    fsm->sii_offset = EC_FIRST_SII_CATEGORY_OFFSET; // first category header
    ec_fsm_sii_read(&fsm->fsm_sii, slave, fsm->sii_offset,
            EC_FSM_SII_USE_CONFIGURED_ADDRESS);
    fsm->state = ec_fsm_slave_scan_state_sii_size;
    fsm->state(fsm); // execute state immediately
}

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

/**
   Slave scan state: SII SIZE.
*/

void ec_fsm_slave_scan_state_sii_size(ec_fsm_slave_scan_t *fsm /**< slave state machine */)
{
    ec_slave_t *slave = fsm->slave;
    uint16_t cat_type, cat_size;

    if (ec_fsm_sii_exec(&fsm->fsm_sii)) return;

    if (!ec_fsm_sii_success(&fsm->fsm_sii)) {
        fsm->slave->error_flag = 1;
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_ERR("Failed to read SII size of slave %u.\n",
               slave->ring_position);
        return;
    }

    cat_type = EC_READ_U16(fsm->fsm_sii.value);
    cat_size = EC_READ_U16(fsm->fsm_sii.value + 2);

    if (cat_type != 0xFFFF) { // not the last category
        off_t next_offset = 2UL + fsm->sii_offset + cat_size;
        if (next_offset >= EC_MAX_SII_SIZE) {
            EC_WARN("SII size of slave %u exceeds"
                    " %u words (0xffff limiter missing?).\n",
                    slave->ring_position, EC_MAX_SII_SIZE);
            // cut off category data...
            slave->sii_nwords = EC_FIRST_SII_CATEGORY_OFFSET;
            goto alloc_sii;
        }
        fsm->sii_offset = next_offset;
        ec_fsm_sii_read(&fsm->fsm_sii, slave, fsm->sii_offset,
                        EC_FSM_SII_USE_CONFIGURED_ADDRESS);
        ec_fsm_sii_exec(&fsm->fsm_sii); // execute state immediately
        return;
    }

    slave->sii_nwords = fsm->sii_offset + 1;

alloc_sii:
    if (slave->sii_words) {
        EC_WARN("Freeing old SII data on slave %u...\n",
                slave->ring_position);
        kfree(slave->sii_words);
    }

    if (!(slave->sii_words =
                (uint16_t *) kmalloc(slave->sii_nwords * 2, GFP_KERNEL))) {
        EC_ERR("Failed to allocate %u words of SII data for slave %u.\n",
               slave->sii_nwords, slave->ring_position);
        slave->sii_nwords = 0;
        slave->error_flag = 1;
        fsm->state = ec_fsm_slave_scan_state_error;
        return;
    }

    // Start fetching SII contents

    fsm->state = ec_fsm_slave_scan_state_sii_data;
    fsm->sii_offset = 0x0000;
    ec_fsm_sii_read(&fsm->fsm_sii, slave, fsm->sii_offset,
            EC_FSM_SII_USE_CONFIGURED_ADDRESS);
    ec_fsm_sii_exec(&fsm->fsm_sii); // execute state immediately
}

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

/**
   Slave scan state: SII DATA.
*/

void ec_fsm_slave_scan_state_sii_data(ec_fsm_slave_scan_t *fsm /**< slave state machine */)
{
    ec_slave_t *slave = fsm->slave;
    uint16_t *cat_word, cat_type, cat_size;

    if (ec_fsm_sii_exec(&fsm->fsm_sii)) return;

    if (!ec_fsm_sii_success(&fsm->fsm_sii)) {
        fsm->slave->error_flag = 1;
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_ERR("Failed to fetch SII contents of slave %u.\n",
               slave->ring_position);
        return;
    }

    // 2 words fetched

    if (fsm->sii_offset + 2 <= slave->sii_nwords) { // 2 words fit
        memcpy(slave->sii_words + fsm->sii_offset, fsm->fsm_sii.value, 4);
    } else { // copy the last word
        memcpy(slave->sii_words + fsm->sii_offset, fsm->fsm_sii.value, 2);
    }

    if (fsm->sii_offset + 2 < slave->sii_nwords) {
        // fetch the next 2 words
        fsm->sii_offset += 2;
        ec_fsm_sii_read(&fsm->fsm_sii, slave, fsm->sii_offset,
                        EC_FSM_SII_USE_CONFIGURED_ADDRESS);
        ec_fsm_sii_exec(&fsm->fsm_sii); // execute state immediately
        return;
    }

    // Evaluate SII contents
    
    ec_slave_clear_sync_managers(slave);

    slave->sii.alias =
        EC_READ_U16(slave->sii_words + 0x0004);
    slave->sii.vendor_id =
        EC_READ_U32(slave->sii_words + 0x0008);
    slave->sii.product_code =
        EC_READ_U32(slave->sii_words + 0x000A);
    slave->sii.revision_number =
        EC_READ_U32(slave->sii_words + 0x000C);
    slave->sii.serial_number =
        EC_READ_U32(slave->sii_words + 0x000E);
    slave->sii.boot_rx_mailbox_offset =
        EC_READ_U16(slave->sii_words + 0x0014);
    slave->sii.boot_rx_mailbox_size =
        EC_READ_U16(slave->sii_words + 0x0015);
    slave->sii.boot_tx_mailbox_offset =
        EC_READ_U16(slave->sii_words + 0x0016);
    slave->sii.boot_tx_mailbox_size =
        EC_READ_U16(slave->sii_words + 0x0017);
    slave->sii.std_rx_mailbox_offset =
        EC_READ_U16(slave->sii_words + 0x0018);
    slave->sii.std_rx_mailbox_size =
        EC_READ_U16(slave->sii_words + 0x0019);
    slave->sii.std_tx_mailbox_offset =
        EC_READ_U16(slave->sii_words + 0x001A);
    slave->sii.std_tx_mailbox_size =
        EC_READ_U16(slave->sii_words + 0x001B);
    slave->sii.mailbox_protocols =
        EC_READ_U16(slave->sii_words + 0x001C);

    if (slave->sii_nwords == EC_FIRST_SII_CATEGORY_OFFSET) {
        // sii does not contain category data
        fsm->state = ec_fsm_slave_scan_state_end;
        return;
    }

    if (slave->sii_nwords < EC_FIRST_SII_CATEGORY_OFFSET + 1) {
        EC_ERR("Unexpected end of SII data in slave %u:"
                " First category header missing.\n",
                slave->ring_position);
        goto end;
    }

    // evaluate category data
    cat_word = slave->sii_words + EC_FIRST_SII_CATEGORY_OFFSET;
    while (EC_READ_U16(cat_word) != 0xFFFF) {

        // type and size words must fit
        if (cat_word + 2 - slave->sii_words > slave->sii_nwords) {
            EC_ERR("Unexpected end of SII data in slave %u:"
                    " Category header incomplete.\n",
                    slave->ring_position);
            goto end;
        }

        cat_type = EC_READ_U16(cat_word) & 0x7FFF;
        cat_size = EC_READ_U16(cat_word + 1);
        cat_word += 2;

        if (cat_word + cat_size - slave->sii_words > slave->sii_nwords) {
            EC_WARN("Unexpected end of SII data in slave %u:"
                    " Category data incomplete.\n",
                    slave->ring_position);
            goto end;
        }

        switch (cat_type) {
            case 0x000A:
                if (ec_slave_fetch_sii_strings(slave, (uint8_t *) cat_word,
                            cat_size * 2))
                    goto end;
                break;
            case 0x001E:
                if (ec_slave_fetch_sii_general(slave, (uint8_t *) cat_word,
                            cat_size * 2))
                    goto end;
                break;
            case 0x0028:
                break;
            case 0x0029:
                if (ec_slave_fetch_sii_syncs(slave, (uint8_t *) cat_word,
                            cat_size * 2))
                    goto end;
                break;
            case 0x0032:
                if (ec_slave_fetch_sii_pdos( slave, (uint8_t *) cat_word,
                            cat_size * 2, EC_DIR_INPUT)) // TxPDO
                    goto end;
                break;
            case 0x0033:
                if (ec_slave_fetch_sii_pdos( slave, (uint8_t *) cat_word,
                            cat_size * 2, EC_DIR_OUTPUT)) // RxPDO
                    goto end;
                break;
            default:
                if (fsm->slave->master->debug_level)
                    EC_WARN("Unknown category type 0x%04X in slave %u.\n",
                            cat_type, slave->ring_position);
        }

        cat_word += cat_size;
        if (cat_word - slave->sii_words >= slave->sii_nwords) {
            EC_WARN("Unexpected end of SII data in slave %u:"
                    " Next category header missing.\n",
                    slave->ring_position);
            goto end;
        }
    }

    if (slave->sii.mailbox_protocols & EC_MBOX_COE) {
        ec_fsm_slave_scan_enter_preop(fsm);
    } else {
        fsm->state = ec_fsm_slave_scan_state_end;
    }
    return;

end:
    EC_ERR("Failed to analyze category data.\n");
    fsm->slave->error_flag = 1;
    fsm->state = ec_fsm_slave_scan_state_error;
}

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

/** Enter slave scan state PREOP.
 */
void ec_fsm_slave_scan_enter_preop(
        ec_fsm_slave_scan_t *fsm /**< slave state machine */
        )
{
    ec_slave_t *slave = fsm->slave;
    uint8_t current_state = slave->current_state & EC_SLAVE_STATE_MASK;

    if (current_state != EC_SLAVE_STATE_PREOP
            && current_state != EC_SLAVE_STATE_SAFEOP
            && current_state != EC_SLAVE_STATE_OP) {
        if (slave->master->debug_level) {
            char str[EC_STATE_STRING_SIZE];
            ec_state_string(current_state, str, 0);
            EC_DBG("Slave %u is not in the state to do mailbox com (%s),"
                    " setting to PREOP.\n", slave->ring_position, str);
        }

        fsm->state = ec_fsm_slave_scan_state_preop;
        ec_slave_request_state(slave, EC_SLAVE_STATE_PREOP);
        ec_fsm_slave_config_start(fsm->fsm_slave_config, slave);
        ec_fsm_slave_config_exec(fsm->fsm_slave_config);
    } else {
        if (slave->master->debug_level)
            EC_DBG("Reading mailbox syncmanager configuration of slave %u.\n",
                    slave->ring_position);

        /* Scan current sync manager configuration to get configured mailbox
         * sizes. */
        ec_datagram_fprd(fsm->datagram, slave->station_address, 0x0800,
                EC_SYNC_PAGE_SIZE * 2);
        fsm->retries = EC_FSM_RETRIES;
        fsm->state = ec_fsm_slave_scan_state_sync;
    }
}

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

/** Slave scan state: PREOP.
 */
void ec_fsm_slave_scan_state_preop(
        ec_fsm_slave_scan_t *fsm /**< slave state machine */
        )
{
    if (ec_fsm_slave_config_exec(fsm->fsm_slave_config))
        return;

    if (!ec_fsm_slave_config_success(fsm->fsm_slave_config)) {
        fsm->state = ec_fsm_slave_scan_state_error;
        return;
    }

    ec_fsm_slave_scan_enter_pdos(fsm);
}

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

/** Slave scan state: SYNC.
 */
void ec_fsm_slave_scan_state_sync(
        ec_fsm_slave_scan_t *fsm /**< slave 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_slave_scan_state_error;
        EC_ERR("Failed to receive sync manager configuration datagram"
                " from slave %u (datagram state %u).\n",
               slave->ring_position, datagram->state);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->slave->error_flag = 1;
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_ERR("Failed to read DL status from slave %u: ",
               slave->ring_position);
        ec_datagram_print_wc_error(datagram);
        return;
    }

    slave->configured_rx_mailbox_offset = EC_READ_U16(datagram->data);
    slave->configured_rx_mailbox_size = EC_READ_U16(datagram->data + 2);
    slave->configured_tx_mailbox_offset = EC_READ_U16(datagram->data + 8);
    slave->configured_tx_mailbox_size = EC_READ_U16(datagram->data + 10);

    if (slave->master->debug_level) {
        EC_DBG("Mailbox configuration of slave %u:\n", slave->ring_position);
        EC_DBG(" RX offset=0x%04x size=%u\n",
                slave->configured_rx_mailbox_offset,
                slave->configured_rx_mailbox_size);
        EC_DBG(" TX offset=0x%04x size=%u\n",
                slave->configured_tx_mailbox_offset,
                slave->configured_tx_mailbox_size);
    }

    ec_fsm_slave_scan_enter_pdos(fsm);
}

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

/** Enter slave scan state PDOS.
 */
void ec_fsm_slave_scan_enter_pdos(
        ec_fsm_slave_scan_t *fsm /**< slave state machine */
        )
{
    ec_slave_t *slave = fsm->slave;

    if (slave->master->debug_level)
        EC_DBG("Scanning PDO assignment and mapping of slave %u.\n",
                slave->ring_position);
    fsm->state = ec_fsm_slave_scan_state_pdos;
    ec_fsm_pdo_start_reading(fsm->fsm_pdo, slave);
    ec_fsm_pdo_exec(fsm->fsm_pdo); // execute immediately
}

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

/** Slave scan state: PDOS.
 */
void ec_fsm_slave_scan_state_pdos(
        ec_fsm_slave_scan_t *fsm /**< slave state machine */
        )
{
    if (ec_fsm_pdo_exec(fsm->fsm_pdo))
        return;

    if (!ec_fsm_pdo_success(fsm->fsm_pdo)) {
        fsm->state = ec_fsm_slave_scan_state_error;
        return;
    }

    // reading PDO configuration finished
    fsm->state = ec_fsm_slave_scan_state_end;
}

/******************************************************************************
 * Common state functions
 *****************************************************************************/

/** State: ERROR.
 */
void ec_fsm_slave_scan_state_error(
        ec_fsm_slave_scan_t *fsm /**< slave state machine */
        )
{
}

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

/** State: END.
 */
void ec_fsm_slave_scan_state_end(
        ec_fsm_slave_scan_t *fsm /**< slave state machine */
        )
{
}

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