slave.c

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/******************************************************************************
 *
 *  $Id: slave.c 533 2006-09-01 12:35:41Z fp $
 *
 *  Copyright (C) 2006  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
 *  as published by the Free Software Foundation; either version 2 of the
 *  License, or (at your option) any later version.
 *
 *  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 right to use EtherCAT Technology is granted and comes free of
 *  charge under condition of compatibility of product made by
 *  Licensee. People intending to distribute/sell products based on the
 *  code, have to sign an agreement to guarantee that products using
 *  software based on IgH EtherCAT master stay compatible with the actual
 *  EtherCAT specification (which are released themselves as an open
 *  standard) as the (only) precondition to have the right to use EtherCAT
 *  Technology, IP and trade marks.
 *
 *****************************************************************************/

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

#include <linux/module.h>
#include <linux/delay.h>

#include "globals.h"
#include "slave.h"
#include "datagram.h"
#include "master.h"

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

extern const ec_code_msg_t al_status_messages[];

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

ssize_t ec_show_slave_attribute(struct kobject *, struct attribute *, char *);
ssize_t ec_store_slave_attribute(struct kobject *, struct attribute *,
                                 const char *, size_t);

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

EC_SYSFS_READ_ATTR(info);
EC_SYSFS_READ_WRITE_ATTR(state);
EC_SYSFS_READ_WRITE_ATTR(eeprom);

static struct attribute *def_attrs[] = {
    &attr_info,
    &attr_state,
    &attr_eeprom,
    NULL,
};

static struct sysfs_ops sysfs_ops = {
    .show = ec_show_slave_attribute,
    .store = ec_store_slave_attribute
};

static struct kobj_type ktype_ec_slave = {
    .release = ec_slave_clear,
    .sysfs_ops = &sysfs_ops,
    .default_attrs = def_attrs
};

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

int ec_slave_init(ec_slave_t *slave, 
                  ec_master_t *master, 
                  uint16_t ring_position, 
                  uint16_t station_address 
                  )
{
    unsigned int i;

    slave->ring_position = ring_position;
    slave->station_address = station_address;

    // init kobject and add it to the hierarchy
    memset(&slave->kobj, 0x00, sizeof(struct kobject));
    kobject_init(&slave->kobj);
    slave->kobj.ktype = &ktype_ec_slave;
    slave->kobj.parent = &master->kobj;
    if (kobject_set_name(&slave->kobj, "slave%03i", slave->ring_position)) {
        EC_ERR("Failed to set kobject name.\n");
        kobject_put(&slave->kobj);
        return -1;
    }

    slave->master = master;

    slave->requested_state = EC_SLAVE_STATE_UNKNOWN;
    slave->current_state = EC_SLAVE_STATE_UNKNOWN;
    slave->error_flag = 0;
    slave->online = 1;
    slave->fmmu_count = 0;
    slave->registered = 0;

    slave->coupler_index = 0;
    slave->coupler_subindex = 0xFFFF;

    slave->base_type = 0;
    slave->base_revision = 0;
    slave->base_build = 0;
    slave->base_fmmu_count = 0;
    slave->base_sync_count = 0;

    slave->eeprom_data = NULL;
    slave->eeprom_size = 0;
    slave->new_eeprom_data = NULL;
    slave->new_eeprom_size = 0;

    slave->sii_alias = 0;
    slave->sii_vendor_id = 0;
    slave->sii_product_code = 0;
    slave->sii_revision_number = 0;
    slave->sii_serial_number = 0;
    slave->sii_rx_mailbox_offset = 0;
    slave->sii_rx_mailbox_size = 0;
    slave->sii_tx_mailbox_offset = 0;
    slave->sii_tx_mailbox_size = 0;
    slave->sii_mailbox_protocols = 0;
    slave->sii_group = NULL;
    slave->sii_image = NULL;
    slave->sii_order = NULL;
    slave->sii_name = NULL;

    INIT_LIST_HEAD(&slave->sii_strings);
    INIT_LIST_HEAD(&slave->sii_syncs);
    INIT_LIST_HEAD(&slave->sii_pdos);
    INIT_LIST_HEAD(&slave->sdo_dictionary);
    INIT_LIST_HEAD(&slave->sdo_confs);
    INIT_LIST_HEAD(&slave->varsize_fields);

    for (i = 0; i < 4; i++) {
        slave->dl_link[i] = 0;
        slave->dl_loop[i] = 0;
        slave->dl_signal[i] = 0;
        slave->sii_physical_layer[i] = 0xFF;
    }

    return 0;
}

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

void ec_slave_clear(struct kobject *kobj )
{
    ec_slave_t *slave;
    ec_sii_string_t *string, *next_str;
    ec_sii_sync_t *sync, *next_sync;
    ec_sii_pdo_t *pdo, *next_pdo;
    ec_sii_pdo_entry_t *entry, *next_ent;
    ec_sdo_t *sdo, *next_sdo;
    ec_sdo_entry_t *en, *next_en;
    ec_sdo_data_t *sdodata, *next_sdodata;
    ec_varsize_t *var, *next_var;

    slave = container_of(kobj, ec_slave_t, kobj);

    // free all string objects
    list_for_each_entry_safe(string, next_str, &slave->sii_strings, list) {
        list_del(&string->list);
        kfree(string);
    }

    // free all sync managers
    list_for_each_entry_safe(sync, next_sync, &slave->sii_syncs, list) {
        list_del(&sync->list);
        kfree(sync);
    }

    // free all PDOs
    list_for_each_entry_safe(pdo, next_pdo, &slave->sii_pdos, list) {
        list_del(&pdo->list);
        if (pdo->name) kfree(pdo->name);

        // free all PDO entries
        list_for_each_entry_safe(entry, next_ent, &pdo->entries, list) {
            list_del(&entry->list);
            if (entry->name) kfree(entry->name);
            kfree(entry);
        }

        kfree(pdo);
    }

    if (slave->sii_group) kfree(slave->sii_group);
    if (slave->sii_image) kfree(slave->sii_image);
    if (slave->sii_order) kfree(slave->sii_order);
    if (slave->sii_name) kfree(slave->sii_name);

    // free all SDOs
    list_for_each_entry_safe(sdo, next_sdo, &slave->sdo_dictionary, list) {
        list_del(&sdo->list);
        if (sdo->name) kfree(sdo->name);

        // free all SDO entries
        list_for_each_entry_safe(en, next_en, &sdo->entries, list) {
            list_del(&en->list);
            kfree(en);
        }
        kfree(sdo);
    }

    // free all SDO configurations
    list_for_each_entry_safe(sdodata, next_sdodata, &slave->sdo_confs, list) {
        list_del(&sdodata->list);
        kfree(sdodata->data);
        kfree(sdodata);
    }

    // free information about variable sized data fields
    list_for_each_entry_safe(var, next_var, &slave->varsize_fields, list) {
        list_del(&var->list);
        kfree(var);
    }

    if (slave->eeprom_data) kfree(slave->eeprom_data);
    if (slave->new_eeprom_data) kfree(slave->new_eeprom_data);
}

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

int ec_slave_fetch_strings(ec_slave_t *slave, 
                           const uint8_t *data 
                           )
{
    unsigned int string_count, i;
    size_t size;
    off_t offset;
    ec_sii_string_t *string;

    string_count = data[0];
    offset = 1;
    for (i = 0; i < string_count; i++) {
        size = data[offset];
        // allocate memory for string structure and data at a single blow
        if (!(string = (ec_sii_string_t *)
              kmalloc(sizeof(ec_sii_string_t) + size + 1, GFP_ATOMIC))) {
            EC_ERR("Failed to allocate string memory.\n");
            return -1;
        }
        string->size = size;
        // string memory appended to string structure
        string->data = (char *) string + sizeof(ec_sii_string_t);
        memcpy(string->data, data + offset + 1, size);
        string->data[size] = 0x00;
        list_add_tail(&string->list, &slave->sii_strings);
        offset += 1 + size;
    }

    return 0;
}

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

void ec_slave_fetch_general(ec_slave_t *slave, 
                            const uint8_t *data 
                            )
{
    unsigned int i;

    ec_slave_locate_string(slave, data[0], &slave->sii_group);
    ec_slave_locate_string(slave, data[1], &slave->sii_image);
    ec_slave_locate_string(slave, data[2], &slave->sii_order);
    ec_slave_locate_string(slave, data[3], &slave->sii_name);

    for (i = 0; i < 4; i++)
        slave->sii_physical_layer[i] =
            (data[4] & (0x03 << (i * 2))) >> (i * 2);
}

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

int ec_slave_fetch_sync(ec_slave_t *slave, 
                        const uint8_t *data, 
                        size_t word_count 
                        )
{
    unsigned int sync_count, i;
    ec_sii_sync_t *sync;

    sync_count = word_count / 4; // sync manager struct is 4 words long

    for (i = 0; i < sync_count; i++, data += 8) {
        if (!(sync = (ec_sii_sync_t *)
              kmalloc(sizeof(ec_sii_sync_t), GFP_ATOMIC))) {
            EC_ERR("Failed to allocate Sync-Manager memory.\n");
            return -1;
        }

        sync->index = i;
        sync->physical_start_address = EC_READ_U16(data);
        sync->length                 = EC_READ_U16(data + 2);
        sync->control_register       = EC_READ_U8 (data + 4);
        sync->enable                 = EC_READ_U8 (data + 6);

        list_add_tail(&sync->list, &slave->sii_syncs);
    }

    return 0;
}

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

int ec_slave_fetch_pdo(ec_slave_t *slave, 
                       const uint8_t *data, 
                       size_t word_count, 
                       ec_sii_pdo_type_t pdo_type 
                       )
{
    ec_sii_pdo_t *pdo;
    ec_sii_pdo_entry_t *entry;
    unsigned int entry_count, i;

    while (word_count >= 4) {
        if (!(pdo = (ec_sii_pdo_t *)
              kmalloc(sizeof(ec_sii_pdo_t), GFP_ATOMIC))) {
            EC_ERR("Failed to allocate PDO memory.\n");
            return -1;
        }

        INIT_LIST_HEAD(&pdo->entries);
        pdo->type = pdo_type;

        pdo->index = EC_READ_U16(data);
        entry_count = EC_READ_U8(data + 2);
        pdo->sync_index = EC_READ_U8(data + 3);
        pdo->name = NULL;
        ec_slave_locate_string(slave, EC_READ_U8(data + 5), &pdo->name);

        list_add_tail(&pdo->list, &slave->sii_pdos);

        word_count -= 4;
        data += 8;

        for (i = 0; i < entry_count; i++) {
            if (!(entry = (ec_sii_pdo_entry_t *)
                  kmalloc(sizeof(ec_sii_pdo_entry_t), GFP_ATOMIC))) {
                EC_ERR("Failed to allocate PDO entry memory.\n");
                return -1;
            }

            entry->index = EC_READ_U16(data);
            entry->subindex = EC_READ_U8(data + 2);
            entry->name = NULL;
            ec_slave_locate_string(slave, EC_READ_U8(data + 3), &entry->name);
            entry->bit_length = EC_READ_U8(data + 5);

            list_add_tail(&entry->list, &pdo->entries);

            word_count -= 4;
            data += 8;
        }
    }

    return 0;
}

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

int ec_slave_locate_string(ec_slave_t *slave, 
                           unsigned int index, 
                           char **ptr 
                           )
{
    ec_sii_string_t *string;
    char *err_string;

    // Erst alten Speicher freigeben
    if (*ptr) {
        kfree(*ptr);
        *ptr = NULL;
    }

    // Index 0 bedeutet "nicht belegt"
    if (!index) return 0;

    // EEPROM-String mit Index finden und kopieren
    list_for_each_entry(string, &slave->sii_strings, list) {
        if (--index) continue;

        if (!(*ptr = (char *) kmalloc(string->size + 1, GFP_ATOMIC))) {
            EC_ERR("Unable to allocate string memory.\n");
            return -1;
        }
        memcpy(*ptr, string->data, string->size + 1);
        return 0;
    }

    EC_WARN("String %i not found in slave %i.\n", index, slave->ring_position);

    err_string = "(string not found)";

    if (!(*ptr = (char *) kmalloc(strlen(err_string) + 1, GFP_ATOMIC))) {
        EC_WARN("Unable to allocate string memory.\n");
        return -1;
    }

    memcpy(*ptr, err_string, strlen(err_string) + 1);
    return 0;
}

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

int ec_slave_prepare_fmmu(ec_slave_t *slave, 
                          const ec_domain_t *domain, 
                          const ec_sii_sync_t *sync  
                          )
{
    unsigned int i;

    // FMMU configuration already prepared?
    for (i = 0; i < slave->fmmu_count; i++)
        if (slave->fmmus[i].domain == domain && slave->fmmus[i].sync == sync)
            return 0;

    // reserve new FMMU...

    if (slave->fmmu_count >= slave->base_fmmu_count) {
        EC_ERR("Slave %i FMMU limit reached!\n", slave->ring_position);
        return -1;
    }

    slave->fmmus[slave->fmmu_count].domain = domain;
    slave->fmmus[slave->fmmu_count].sync = sync;
    slave->fmmus[slave->fmmu_count].logical_start_address = 0;
    slave->fmmu_count++;
    slave->registered = 1;

    return 0;
}

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

size_t ec_slave_info(const ec_slave_t *slave, 
                     char *buffer 
                     )
{
    off_t off = 0;
    ec_sii_sync_t *sync;
    ec_sii_pdo_t *pdo;
    ec_sii_pdo_entry_t *pdo_entry;
    int first, i;

    off += sprintf(buffer + off, "\nName: ");

    if (slave->sii_name)
        off += sprintf(buffer + off, "%s", slave->sii_name);

    off += sprintf(buffer + off, "\nVendor ID: 0x%08X\n",
                   slave->sii_vendor_id);
    off += sprintf(buffer + off, "Product code: 0x%08X\n\n",
                   slave->sii_product_code);

    off += sprintf(buffer + off, "State: ");
    off += ec_state_string(slave->current_state, buffer + off);
    off += sprintf(buffer + off, "\nRing position: %i\n",
                   slave->ring_position);
    off += sprintf(buffer + off, "Advanced position: %i:%i\n\n",
                   slave->coupler_index, slave->coupler_subindex);

    off += sprintf(buffer + off, "Data link status:\n");
    for (i = 0; i < 4; i++) {
        off += sprintf(buffer + off, "  Port %i (", i);
        switch (slave->sii_physical_layer[i]) {
            case 0x00:
                off += sprintf(buffer + off, "EBUS");
                break;
            case 0x01:
                off += sprintf(buffer + off, "100BASE-TX");
                break;
            case 0x02:
                off += sprintf(buffer + off, "100BASE-FX");
                break;
            default:
                off += sprintf(buffer + off, "unknown (%i)",
                               slave->sii_physical_layer[i]);
        }
        off += sprintf(buffer + off, ") Link %s, Loop %s, %s\n",
                       slave->dl_link[i] ? "up" : "down",
                       slave->dl_loop[i] ? "closed" : "open",
                       slave->dl_signal[i] ? "Signal detected" : "No signal");
    }

    if (slave->sii_mailbox_protocols) {
        off += sprintf(buffer + off, "\nMailboxes:\n");
        off += sprintf(buffer + off, "  RX mailbox: 0x%04X/%i,"
                       " TX mailbox: 0x%04X/%i\n",
                       slave->sii_rx_mailbox_offset,
                       slave->sii_rx_mailbox_size,
                       slave->sii_tx_mailbox_offset,
                       slave->sii_tx_mailbox_size);
        off += sprintf(buffer + off, "  Supported protocols: ");

        first = 1;
        if (slave->sii_mailbox_protocols & EC_MBOX_AOE) {
            off += sprintf(buffer + off, "AoE");
            first = 0;
        }
        if (slave->sii_mailbox_protocols & EC_MBOX_EOE) {
            if (!first) off += sprintf(buffer + off, ", ");
            off += sprintf(buffer + off, "EoE");
            first = 0;
        }
        if (slave->sii_mailbox_protocols & EC_MBOX_COE) {
            if (!first) off += sprintf(buffer + off, ", ");
            off += sprintf(buffer + off, "CoE");
            first = 0;
        }
        if (slave->sii_mailbox_protocols & EC_MBOX_FOE) {
            if (!first) off += sprintf(buffer + off, ", ");
            off += sprintf(buffer + off, "FoE");
            first = 0;
        }
        if (slave->sii_mailbox_protocols & EC_MBOX_SOE) {
            if (!first) off += sprintf(buffer + off, ", ");
            off += sprintf(buffer + off, "SoE");
            first = 0;
        }
        if (slave->sii_mailbox_protocols & EC_MBOX_VOE) {
            if (!first) off += sprintf(buffer + off, ", ");
            off += sprintf(buffer + off, "VoE");
        }
        off += sprintf(buffer + off, "\n");
    }

    if (slave->sii_alias || slave->sii_group
        || slave->sii_image || slave->sii_order)
        off += sprintf(buffer + off, "\nSII data:\n");

    if (slave->sii_alias)
        off += sprintf(buffer + off, "  Configured station alias:"
                       " 0x%04X (%i)\n", slave->sii_alias, slave->sii_alias);
    if (slave->sii_group)
        off += sprintf(buffer + off, "  Group: %s\n", slave->sii_group);
    if (slave->sii_image)
        off += sprintf(buffer + off, "  Image: %s\n", slave->sii_image);
    if (slave->sii_order)
        off += sprintf(buffer + off, "  Order number: %s\n", slave->sii_order);

    if (!list_empty(&slave->sii_syncs))
        off += sprintf(buffer + off, "\nSync-Managers:\n");

    list_for_each_entry(sync, &slave->sii_syncs, list) {
        off += sprintf(buffer + off, "  %i: 0x%04X, length %i,"
                       " control 0x%02X, %s\n",
                       sync->index, sync->physical_start_address,
                       sync->length, sync->control_register,
                       sync->enable ? "enable" : "disable");
    }

    if (!list_empty(&slave->sii_pdos))
        off += sprintf(buffer + off, "\nPDOs:\n");

    list_for_each_entry(pdo, &slave->sii_pdos, list) {
        off += sprintf(buffer + off,
                       "  %s \"%s\" (0x%04X), Sync-Manager %i\n",
                       pdo->type == EC_RX_PDO ? "RXPDO" : "TXPDO",
                       pdo->name ? pdo->name : "???",
                       pdo->index, pdo->sync_index);

        list_for_each_entry(pdo_entry, &pdo->entries, list) {
            off += sprintf(buffer + off, "    \"%s\" 0x%04X:%X, %i bit\n",
                           pdo_entry->name ? pdo_entry->name : "???",
                           pdo_entry->index, pdo_entry->subindex,
                           pdo_entry->bit_length);
        }
    }

    off += sprintf(buffer + off, "\n");

    return off;
}

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

ssize_t ec_slave_write_eeprom(ec_slave_t *slave, 
                              const uint8_t *data, 
                              size_t size 
                              )
{
    uint16_t word_size, cat_type, cat_size;
    const uint16_t *data_words, *next_header;
    uint16_t *new_data;

    if (!slave->master->eeprom_write_enable) {
        EC_ERR("Writing EEPROMs not allowed! Enable via"
               " eeprom_write_enable SysFS entry.\n");
        return -1;
    }

    if (slave->master->mode != EC_MASTER_MODE_IDLE) {
        EC_ERR("Writing EEPROMs only allowed in idle mode!\n");
        return -1;
    }

    if (slave->new_eeprom_data) {
        EC_ERR("Slave %i already has a pending EEPROM write operation!\n",
               slave->ring_position);
        return -1;
    }

    // coarse check of the data

    if (size % 2) {
        EC_ERR("EEPROM size is odd! Dropping.\n");
        return -1;
    }

    data_words = (const uint16_t *) data;
    word_size = size / 2;

    if (word_size < 0x0041) {
        EC_ERR("EEPROM data too short! Dropping.\n");
        return -1;
    }

    next_header = data_words + 0x0040;
    cat_type = EC_READ_U16(next_header);
    while (cat_type != 0xFFFF) {
        cat_type = EC_READ_U16(next_header);
        cat_size = EC_READ_U16(next_header + 1);
        if ((next_header + cat_size + 2) - data_words >= word_size) {
            EC_ERR("EEPROM data seems to be corrupted! Dropping.\n");
            return -1;
        }
        next_header += cat_size + 2;
        cat_type = EC_READ_U16(next_header);
    }

    // data ok!

    if (!(new_data = (uint16_t *) kmalloc(word_size * 2, GFP_KERNEL))) {
        EC_ERR("Unable to allocate memory for new EEPROM data!\n");
        return -1;
    }
    memcpy(new_data, data, size);

    slave->new_eeprom_size = word_size;
    slave->new_eeprom_data = new_data;

    EC_INFO("EEPROM writing scheduled for slave %i, %i words.\n",
            slave->ring_position, word_size);
    return 0;
}

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

ssize_t ec_show_slave_attribute(struct kobject *kobj, 
                                struct attribute *attr, 
                                char *buffer 
                                )
{
    ec_slave_t *slave = container_of(kobj, ec_slave_t, kobj);

    if (attr == &attr_info) {
        return ec_slave_info(slave, buffer);
    }
    else if (attr == &attr_state) {
        switch (slave->current_state) {
            case EC_SLAVE_STATE_INIT:
                return sprintf(buffer, "INIT\n");
            case EC_SLAVE_STATE_PREOP:
                return sprintf(buffer, "PREOP\n");
            case EC_SLAVE_STATE_SAVEOP:
                return sprintf(buffer, "SAVEOP\n");
            case EC_SLAVE_STATE_OP:
                return sprintf(buffer, "OP\n");
            default:
                return sprintf(buffer, "UNKNOWN\n");
        }
    }
    else if (attr == &attr_eeprom) {
        if (slave->eeprom_data) {
            if (slave->eeprom_size > PAGE_SIZE) {
                EC_ERR("EEPROM contents of slave %i exceed 1 page (%i/%i).\n",
                       slave->ring_position, slave->eeprom_size,
                       (int) PAGE_SIZE);
            }
            else {
                memcpy(buffer, slave->eeprom_data, slave->eeprom_size);
                return slave->eeprom_size;
            }
        }
    }

    return 0;
}

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

ssize_t ec_store_slave_attribute(struct kobject *kobj, 
                                 struct attribute *attr, 
                                 const char *buffer, 
                                 size_t size 
                                 )
{
    ec_slave_t *slave = container_of(kobj, ec_slave_t, kobj);

    if (attr == &attr_state) {
        char state[25];
        if (!strcmp(buffer, "INIT\n"))
            slave->requested_state = EC_SLAVE_STATE_INIT;
        else if (!strcmp(buffer, "PREOP\n"))
            slave->requested_state = EC_SLAVE_STATE_PREOP;
        else if (!strcmp(buffer, "SAVEOP\n"))
            slave->requested_state = EC_SLAVE_STATE_SAVEOP;
        else if (!strcmp(buffer, "OP\n"))
            slave->requested_state = EC_SLAVE_STATE_OP;
        else {
            EC_ERR("Invalid slave state \"%s\"!\n", buffer);
            return -EINVAL;
        }

        ec_state_string(slave->requested_state, state);
        EC_INFO("Accepted new state %s for slave %i.\n",
                state, slave->ring_position);
        slave->error_flag = 0;
        return size;
    }
    else if (attr == &attr_eeprom) {
        if (!ec_slave_write_eeprom(slave, buffer, size))
            return size;
    }

    return -EINVAL;
}

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

uint16_t ec_slave_calc_sync_size(const ec_slave_t *slave,
                                 const ec_sii_sync_t *sync
                                 )
{
    ec_sii_pdo_t *pdo;
    ec_sii_pdo_entry_t *pdo_entry;
    unsigned int bit_size;

    if (sync->length) return sync->length;

    bit_size = 0;
    list_for_each_entry(pdo, &slave->sii_pdos, list) {
        if (pdo->sync_index != sync->index) continue;

        list_for_each_entry(pdo_entry, &pdo->entries, list) {
            bit_size += pdo_entry->bit_length;
        }
    }

    if (bit_size % 8) // round up to full bytes
        return bit_size / 8 + 1;
    else
        return bit_size / 8;
}

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

int ec_slave_is_coupler(const ec_slave_t *slave )
{
    // TODO: Better bus coupler criterion
    return slave->sii_vendor_id == 0x00000002
        && slave->sii_product_code == 0x044C2C52;
}

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

int ec_slave_conf_sdo(ec_slave_t *slave, 
                      uint16_t sdo_index, 
                      uint8_t sdo_subindex, 
                      const uint8_t *data, 
                      size_t size 
                      )
{
    ec_sdo_data_t *sdodata;

    if (!(slave->sii_mailbox_protocols & EC_MBOX_COE)) {
        EC_ERR("Slave %i does not support CoE!\n", slave->ring_position);
        return -1;
    }

    if (!(sdodata = (ec_sdo_data_t *)
          kmalloc(sizeof(ec_sdo_data_t), GFP_KERNEL))) {
        EC_ERR("Failed to allocate memory for SDO configuration object!\n");
        return -1;
    }

    if (!(sdodata->data = (uint8_t *) kmalloc(size, GFP_KERNEL))) {
        EC_ERR("Failed to allocate memory for SDO configuration data!\n");
        kfree(sdodata);
        return -1;
    }

    sdodata->index = sdo_index;
    sdodata->subindex = sdo_subindex;
    memcpy(sdodata->data, data, size);
    sdodata->size = size;

    list_add_tail(&sdodata->list, &slave->sdo_confs);
    return 0;
}

/******************************************************************************
 *  Realtime interface
 *****************************************************************************/

int ecrt_slave_conf_sdo8(ec_slave_t *slave, 
                         uint16_t sdo_index, 
                         uint8_t sdo_subindex, 
                         uint8_t value 
                         )
{
    uint8_t data[1];
    EC_WRITE_U8(data, value);
    return ec_slave_conf_sdo(slave, sdo_index, sdo_subindex, data, 1);
}

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

int ecrt_slave_conf_sdo16(ec_slave_t *slave, 
                          uint16_t sdo_index, 
                          uint8_t sdo_subindex, 
                          uint16_t value 
                          )
{
    uint8_t data[2];
    EC_WRITE_U16(data, value);
    return ec_slave_conf_sdo(slave, sdo_index, sdo_subindex, data, 2);
}

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

int ecrt_slave_conf_sdo32(ec_slave_t *slave, 
                          uint16_t sdo_index, 
                          uint8_t sdo_subindex, 
                          uint32_t value 
                          )
{
    uint8_t data[4];
    EC_WRITE_U32(data, value);
    return ec_slave_conf_sdo(slave, sdo_index, sdo_subindex, data, 4);
}

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

int ecrt_slave_pdo_size(ec_slave_t *slave, 
                        uint16_t pdo_index, 
                        uint8_t pdo_subindex, 
                        size_t size 
                        )
{
    EC_WARN("ecrt_slave_pdo_size() currently not available.\n");
    return -1;

#if 0
    unsigned int i, j, field_counter;
    const ec_sii_sync_t *sync;
    const ec_pdo_t *pdo;
    ec_varsize_t *var;

    if (!slave->type) {
        EC_ERR("Slave %i has no type information!\n", slave->ring_position);
        return -1;
    }

    field_counter = 0;
    for (i = 0; (sync = slave->type->sync_managers[i]); i++) {
        for (j = 0; (field = sync->fields[j]); j++) {
            if (!strcmp(field->name, field_name)) {
                if (field_counter++ == field_index) {
                    // is the size of this field variable?
                    if (field->size) {
                        EC_ERR("Field \"%s\"[%i] of slave %i has no variable"
                               " size!\n", field->name, field_index,
                               slave->ring_position);
                        return -1;
                    }
                    // does a size specification already exist?
                    list_for_each_entry(var, &slave->varsize_fields, list) {
                        if (var->field == field) {
                            EC_WARN("Resizing field \"%s\"[%i] of slave %i.\n",
                                    field->name, field_index,
                                    slave->ring_position);
                            var->size = size;
                            return 0;
                        }
                    }
                    // create a new size specification...
                    if (!(var = kmalloc(sizeof(ec_varsize_t), GFP_KERNEL))) {
                        EC_ERR("Failed to allocate memory for varsize_t!\n");
                        return -1;
                    }
                    var->field = field;
                    var->size = size;
                    list_add_tail(&var->list, &slave->varsize_fields);
                    return 0;
                }
            }
        }
    }

    EC_ERR("Slave %i (\"%s %s\") has no field \"%s\"[%i]!\n",
           slave->ring_position, slave->type->vendor_name,
           slave->type->product_name, field_name, field_index);
    return -1;
#endif
}

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

EXPORT_SYMBOL(ecrt_slave_conf_sdo8);
EXPORT_SYMBOL(ecrt_slave_conf_sdo16);
EXPORT_SYMBOL(ecrt_slave_conf_sdo32);
EXPORT_SYMBOL(ecrt_slave_pdo_size);

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

---