fsm_slave_scan.c

Go to the documentation of this file.

/******************************************************************************
 *
 *  $Id$
 *
 *  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.
 *
 *****************************************************************************/

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

#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 *);
#ifdef EC_SII_ASSIGN
void ec_fsm_slave_scan_state_assign_sii(ec_fsm_slave_scan_t *);
#endif
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 *);
#ifdef EC_REGALIAS
void ec_fsm_slave_scan_state_regalias(ec_fsm_slave_scan_t *);
#endif
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 *);
#ifdef EC_REGALIAS
void ec_fsm_slave_scan_enter_regalias(ec_fsm_slave_scan_t *);
#endif
void ec_fsm_slave_scan_enter_preop(ec_fsm_slave_scan_t *);
void ec_fsm_slave_scan_enter_pdos(ec_fsm_slave_scan_t *);

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

void ec_fsm_slave_scan_init(
        ec_fsm_slave_scan_t *fsm, 
        ec_datagram_t *datagram, 
        ec_fsm_slave_config_t *fsm_slave_config, 
        ec_fsm_pdo_t *fsm_pdo 
        )
{
    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);
}

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

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

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

void ec_fsm_slave_scan_start(
        ec_fsm_slave_scan_t *fsm, 
        ec_slave_t *slave 
        )
{
    fsm->slave = slave;
    fsm->state = ec_fsm_slave_scan_state_start;
}

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

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

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

int ec_fsm_slave_scan_exec(ec_fsm_slave_scan_t *fsm )
{
    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);
}

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

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

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

void ec_fsm_slave_scan_state_start(ec_fsm_slave_scan_t *fsm )
{
    // 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;
}

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

void ec_fsm_slave_scan_state_address(
        ec_fsm_slave_scan_t *fsm 
        )
{
    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_SLAVE_ERR(fsm->slave,
                "Failed to receive station address datagram: ");
        ec_datagram_print_state(datagram);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->slave->error_flag = 1;
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_SLAVE_ERR(fsm->slave, "Failed to write station address: ");
        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;
}

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

void ec_fsm_slave_scan_state_state(
        ec_fsm_slave_scan_t *fsm 
        )
{
    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_SLAVE_ERR(slave, "Failed to receive AL state datagram: ");
        ec_datagram_print_state(datagram);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->slave->error_flag = 1;
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_SLAVE_ERR(slave, "Failed to read AL state: ");
        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_SLAVE_WARN(slave, "Slave has state error bit set (%s)!\n",
                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;
}

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

void ec_fsm_slave_scan_state_base(
        ec_fsm_slave_scan_t *fsm 
        )
{
    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_SLAVE_ERR(slave, "Failed to receive base data datagram: ");
        ec_datagram_print_state(datagram);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->slave->error_flag = 1;
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_SLAVE_ERR(slave, "Failed to read base data: ");
        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_SLAVE_WARN(slave, "Slave has more FMMUs (%u) than the master can"
                " handle (%u).\n", 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_SLAVE_WARN(slave, "Slave provides more sync managers (%u)"
                " than the master can handle (%u).\n",
                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);
    }
}

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

void ec_fsm_slave_scan_state_dc_cap(
        ec_fsm_slave_scan_t *fsm 
        )
{
    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_SLAVE_ERR(slave, "Failed to receive system time datagram: ");
        ec_datagram_print_state(datagram);
        return;
    }

    if (datagram->working_counter == 1) {
        slave->has_dc_system_time = 1;
        EC_SLAVE_DBG(slave, 1, "Slave has the System Time register.\n");
    } else if (datagram->working_counter == 0) {
        EC_SLAVE_DBG(slave, 1, "Slave has no System Time register; delay "
                "measurement only.\n");
    } else {
        fsm->slave->error_flag = 1;
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_SLAVE_ERR(slave, "Failed to determine, if system time register is "
                "supported: ");
        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;
}

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

void ec_fsm_slave_scan_state_dc_times(
        ec_fsm_slave_scan_t *fsm 
        )
{
    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_SLAVE_ERR(slave, "Failed to receive system time datagram: ");
        ec_datagram_print_state(datagram);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->slave->error_flag = 1;
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_SLAVE_ERR(slave, "Failed to get DC receive times: ");
        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);
}

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

void ec_fsm_slave_scan_enter_datalink(
        ec_fsm_slave_scan_t *fsm 
        )
{
    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;
}

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

void ec_fsm_slave_scan_enter_sii_size(
        ec_fsm_slave_scan_t *fsm 
        )
{
    // Start fetching SII size

    fsm->sii_offset = EC_FIRST_SII_CATEGORY_OFFSET; // first category header
    ec_fsm_sii_read(&fsm->fsm_sii, fsm->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
}

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

#ifdef EC_SII_ASSIGN

void ec_fsm_slave_scan_enter_assign_sii(
        ec_fsm_slave_scan_t *fsm 
        )
{
    ec_datagram_t *datagram = fsm->datagram;
    ec_slave_t *slave = fsm->slave;

    EC_SLAVE_DBG(slave, 1, "Assigning SII access to EtherCAT.\n");

    // assign SII to ECAT
    ec_datagram_fpwr(datagram, slave->station_address, 0x0500, 1);
    EC_WRITE_U8(datagram->data, 0x00); // EtherCAT
    fsm->retries = EC_FSM_RETRIES;
    fsm->state = ec_fsm_slave_scan_state_assign_sii;
}

#endif

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

void ec_fsm_slave_scan_state_datalink(
        ec_fsm_slave_scan_t *fsm 
        )
{
    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_SLAVE_ERR(slave, "Failed to receive DL status datagram: ");
        ec_datagram_print_state(datagram);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->slave->error_flag = 1;
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_SLAVE_ERR(slave, "Failed to read DL status: ");
        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;
    }

#ifdef EC_SII_ASSIGN
    ec_fsm_slave_scan_enter_assign_sii(fsm);
#else
    ec_fsm_slave_scan_enter_sii_size(fsm);
#endif
}

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

#ifdef EC_SII_ASSIGN

void ec_fsm_slave_scan_state_assign_sii(
        ec_fsm_slave_scan_t *fsm 
        )
{
    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) {
        EC_SLAVE_WARN(slave, "Failed to receive SII assignment datagram: ");
        ec_datagram_print_state(datagram);
        // Try to go on, probably assignment is correct
        goto continue_with_sii_size;
    }

    if (datagram->working_counter != 1) {
        EC_SLAVE_WARN(slave, "Failed to assign SII to EtherCAT: ");
        ec_datagram_print_wc_error(datagram);
        // Try to go on, probably assignment is correct
    }

continue_with_sii_size:
    ec_fsm_slave_scan_enter_sii_size(fsm);
}

#endif

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

void ec_fsm_slave_scan_state_sii_size(
        ec_fsm_slave_scan_t *fsm 
        )
{
    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_SLAVE_ERR(slave, "Failed to determine SII content size:"
                " Reading word offset 0x%04x failed. Assuming %u words.\n",
                fsm->sii_offset, EC_FIRST_SII_CATEGORY_OFFSET);
        slave->sii_nwords = EC_FIRST_SII_CATEGORY_OFFSET;
        goto alloc_sii;
    }

    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_SLAVE_WARN(slave, "SII size exceeds %u words"
                    " (0xffff limiter missing?).\n", 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_SLAVE_WARN(slave, "Freeing old SII data...\n");
        kfree(slave->sii_words);
    }

    if (!(slave->sii_words =
                (uint16_t *) kmalloc(slave->sii_nwords * 2, GFP_KERNEL))) {
        EC_SLAVE_ERR(slave, "Failed to allocate %zu words of SII data.\n",
               slave->sii_nwords);
        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
}

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

void ec_fsm_slave_scan_state_sii_data(ec_fsm_slave_scan_t *fsm )
{
    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_SLAVE_ERR(slave, "Failed to fetch SII contents.\n");
        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->effective_alias = slave->sii.alias;
    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_SLAVE_ERR(slave, "Unexpected end of SII data:"
                " First category header missing.\n");
        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_SLAVE_ERR(slave, "Unexpected end of SII data:"
                    " Category header incomplete.\n");
            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_SLAVE_WARN(slave, "Unexpected end of SII data:"
                    " Category data incomplete.\n");
            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:
                EC_SLAVE_DBG(slave, 1, "Unknown category type 0x%04X.\n",
                        cat_type);
        }

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

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

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

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

#ifdef EC_REGALIAS

void ec_fsm_slave_scan_enter_regalias(
        ec_fsm_slave_scan_t *fsm 
        )
{
    ec_datagram_t *datagram = fsm->datagram;
    ec_slave_t *slave = fsm->slave;

    // read alias from register
    EC_SLAVE_DBG(slave, 1, "Reading alias from register.\n");
    ec_datagram_fprd(datagram, slave->station_address, 0x0012, 2);
    ec_datagram_zero(datagram);
    fsm->retries = EC_FSM_RETRIES;
    fsm->state = ec_fsm_slave_scan_state_regalias;
}

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

void ec_fsm_slave_scan_state_regalias(
        ec_fsm_slave_scan_t *fsm 
        )
{
    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_SLAVE_ERR(slave, "Failed to receive register alias datagram: ");
        ec_datagram_print_state(datagram);
        return;
    }

    if (datagram->working_counter != 1) {
        EC_SLAVE_DBG(slave, 1, "Failed to read register alias.\n");
    } else {
        slave->effective_alias = EC_READ_U16(datagram->data);
        EC_SLAVE_DBG(slave, 1, "Read alias %u from register.\n",
                slave->effective_alias);
    }

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

#endif // defined EC_REGALIAS

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

void ec_fsm_slave_scan_enter_preop(
        ec_fsm_slave_scan_t *fsm 
        )
{
    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_SLAVE_DBG(slave, 0, "Slave is not in the state"
                    " to do mailbox com (%s), setting to PREOP.\n", 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 {
        EC_SLAVE_DBG(slave, 1, "Reading mailbox"
                " sync manager configuration.\n");

        /* 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;
    }
}

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

void ec_fsm_slave_scan_state_preop(
        ec_fsm_slave_scan_t *fsm 
        )
{
    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);
}

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

void ec_fsm_slave_scan_state_sync(
        ec_fsm_slave_scan_t *fsm 
        )
{
    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_SLAVE_ERR(slave, "Failed to receive sync manager"
                " configuration datagram: ");
        ec_datagram_print_state(datagram);
        return;
    }

    if (datagram->working_counter != 1) {
        fsm->slave->error_flag = 1;
        fsm->state = ec_fsm_slave_scan_state_error;
        EC_SLAVE_ERR(slave, "Failed to read DL status: ");
        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);

    EC_SLAVE_DBG(slave, 1, "Mailbox configuration:\n");
    EC_SLAVE_DBG(slave, 1, " RX offset=0x%04x size=%u\n",
            slave->configured_rx_mailbox_offset,
            slave->configured_rx_mailbox_size);
    EC_SLAVE_DBG(slave, 1, " TX offset=0x%04x size=%u\n",
            slave->configured_tx_mailbox_offset,
            slave->configured_tx_mailbox_size);

    ec_fsm_slave_scan_enter_pdos(fsm);
}

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

void ec_fsm_slave_scan_enter_pdos(
        ec_fsm_slave_scan_t *fsm 
        )
{
    ec_slave_t *slave = fsm->slave;

    EC_SLAVE_DBG(slave, 1, "Scanning PDO assignment and mapping.\n");
    fsm->state = ec_fsm_slave_scan_state_pdos;
    ec_fsm_pdo_start_reading(fsm->fsm_pdo, slave);
    ec_fsm_pdo_exec(fsm->fsm_pdo, fsm->datagram); // execute immediately
}

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

void ec_fsm_slave_scan_state_pdos(
        ec_fsm_slave_scan_t *fsm 
        )
{
    if (ec_fsm_pdo_exec(fsm->fsm_pdo, fsm->datagram)) {
        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
 *****************************************************************************/

void ec_fsm_slave_scan_state_error(
        ec_fsm_slave_scan_t *fsm 
        )
{
}

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

void ec_fsm_slave_scan_state_end(
        ec_fsm_slave_scan_t *fsm 
        )
{
}

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

---