/******************************************************************************
 *
 *  $Id$
 *
 *  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; version 2 of the License.
 *
 *  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
 *
 *****************************************************************************/

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

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

#include "globals.h"
#include "fsm.h"
#include "master.h"

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

#define EC_CAT_MEM 0x100

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

void ec_fsm_master_start(ec_fsm_t *);
void ec_fsm_master_wait(ec_fsm_t *);
void ec_fsm_master_slave(ec_fsm_t *);
void ec_fsm_master_calc(ec_fsm_t *);
void ec_fsm_master_finished(ec_fsm_t *);

void ec_fsm_slave_start(ec_fsm_t *);
void ec_fsm_slave_read_base(ec_fsm_t *);
void ec_fsm_slave_read_dl(ec_fsm_t *);
void ec_fsm_slave_prepare_sii(ec_fsm_t *);
void ec_fsm_slave_read_sii(ec_fsm_t *);
void ec_fsm_slave_categories(ec_fsm_t *);
void ec_fsm_slave_category_header(ec_fsm_t *);
void ec_fsm_slave_category_data(ec_fsm_t *);
void ec_fsm_slave_finished(ec_fsm_t *);

void ec_fsm_sii_start_reading(ec_fsm_t *);
void ec_fsm_sii_check(ec_fsm_t *);
void ec_fsm_sii_fetch(ec_fsm_t *);
void ec_fsm_sii_finished(ec_fsm_t *);
void ec_fsm_sii_error(ec_fsm_t *);

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

int ec_fsm_init(ec_fsm_t *fsm, ec_master_t *master)
{
    fsm->master = master;
    fsm->master_state = ec_fsm_master_start;
    fsm->master_slaves_responding = 0;
    fsm->master_slave_states = EC_SLAVE_STATE_UNKNOWN;
    fsm->slave_cat_data = NULL;

    ec_command_init(&fsm->command);
    if (ec_command_prealloc(&fsm->command, EC_MAX_DATA_SIZE)) {
        EC_ERR("FSM failed to allocate FSM command.\n");
        return -1;
    }

    return 0;
}

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

void ec_fsm_clear(ec_fsm_t *fsm)
{
    if (fsm->slave_cat_data) kfree(fsm->slave_cat_data);
    ec_command_clear(&fsm->command);
}

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

void ec_fsm_reset(ec_fsm_t *fsm)
{
    fsm->master_state = ec_fsm_master_start;
    fsm->master_slaves_responding = 0;
    fsm->master_slave_states = EC_SLAVE_STATE_UNKNOWN;

    if (fsm->slave_cat_data) {
        kfree(fsm->slave_cat_data);
        fsm->slave_cat_data = NULL;
    }
}

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

void ec_fsm_execute(ec_fsm_t *fsm)
{
    fsm->master_state(fsm);
}

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

int ec_fsm_idle(const ec_fsm_t *fsm)
{
    return (fsm->master_state == ec_fsm_master_start ||
            fsm->master_state == ec_fsm_master_wait ||
            fsm->master_state == ec_fsm_master_finished);
}

/******************************************************************************
 *  master state machine
 *****************************************************************************/

/**
   State: Start.
   Starts with getting slave count and slave states.
*/

void ec_fsm_master_start(ec_fsm_t *fsm)
{
    ec_command_brd(&fsm->command, 0x0130, 2);
    ec_master_queue_command(fsm->master, &fsm->command);

    fsm->master_state = ec_fsm_master_wait;
}

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

void ec_fsm_master_wait(ec_fsm_t *fsm)
{
    ec_command_t *command = &fsm->command;
    unsigned int first, topology_change, i;
    ec_slave_t *slave;

    if (command->state != EC_CMD_RECEIVED) {
        fsm->master_state = ec_fsm_master_start;
        fsm->master_state(fsm); // execute immediately
        return;
    }

    if (command->working_counter == fsm->master_slaves_responding &&
        command->data[0] == fsm->master_slave_states) {
        fsm->master_state = ec_fsm_master_start;
        fsm->master_state(fsm); // execute immediately
        return;
    }

    topology_change = command->working_counter !=
        fsm->master_slaves_responding;

    fsm->master_slaves_responding = command->working_counter;
    fsm->master_slave_states = command->data[0];

    EC_INFO("FSM: %i slave%s responding (", fsm->master_slaves_responding,
            fsm->master_slaves_responding == 1 ? "" : "s");

    first = 1;
    if (fsm->master_slave_states & EC_SLAVE_STATE_INIT) {
        printk("INIT");
        first = 0;
    }
    if (fsm->master_slave_states & EC_SLAVE_STATE_PREOP) {
        if (!first) printk(", ");
        printk("PREOP");
        first = 0;
    }
    if (fsm->master_slave_states & EC_SLAVE_STATE_SAVEOP) {
        if (!first) printk(", ");
        printk("SAVEOP");
        first = 0;
    }
    if (fsm->master_slave_states & EC_SLAVE_STATE_OP) {
        if (!first) printk(", ");
        printk("OP");
    }
    printk(")\n");

    if (!topology_change || fsm->master->mode == EC_MASTER_MODE_RUNNING) {
        fsm->master_state = ec_fsm_master_start;
        fsm->master_state(fsm); // execute immediately
        return;
    }

    // topology change!
    ec_master_clear_slaves(fsm->master);

    if (!fsm->master_slaves_responding) {
        // no slaves present -> finish state machine.
        fsm->master_state = ec_fsm_master_start;
        fsm->master_state(fsm); // execute immediately
        return;
    }

    // init slaves
    for (i = 0; i < fsm->master_slaves_responding; i++) {
        if (!(slave =
              (ec_slave_t *) kmalloc(sizeof(ec_slave_t), GFP_ATOMIC))) {
            EC_ERR("FSM failed to allocate slave %i!\n", i);
            fsm->master_state = ec_fsm_master_finished;
            return;
        }

        if (ec_slave_init(slave, fsm->master, i, i + 1)) {
            fsm->master_state = ec_fsm_master_finished;
            return;
        }

        if (kobject_add(&slave->kobj)) {
            EC_ERR("FSM failed to add kobject.\n");
            kobject_put(&slave->kobj); // free
            fsm->master_state = ec_fsm_master_finished;
            return;
        }

        list_add_tail(&slave->list, &fsm->master->slaves);
    }

    // begin scanning of slaves
    fsm->slave = list_entry(fsm->master->slaves.next,
                            ec_slave_t, list);
    fsm->slave_state = ec_fsm_slave_start;

    fsm->master_state = ec_fsm_master_slave;
    fsm->master_state(fsm); // execute immediately
}

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

/**
   State: Get Slave.
   Executes the sub-statemachine of a slave.
*/

void ec_fsm_master_slave(ec_fsm_t *fsm)
{
    ec_master_t *master = fsm->master;

    fsm->slave_state(fsm); // execute slave state machine

    if (fsm->slave_state != ec_fsm_slave_finished) return;

    // have all slaves been fetched?
    if (fsm->slave->list.next == &master->slaves) {
        fsm->master_state = ec_fsm_master_calc;
        fsm->master_state(fsm); // execute immediately
        return;
    }

    // process next slave
    fsm->slave = list_entry(fsm->slave->list.next, ec_slave_t, list);
    fsm->slave_state = ec_fsm_slave_start;
    fsm->slave_state(fsm); // execute immediately
}

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

/**
   Free-Run state: Calc.
*/

void ec_fsm_master_calc(ec_fsm_t *fsm)
{
    uint16_t coupler_index, coupler_subindex;
    uint16_t reverse_coupler_index, current_coupler_index;
    ec_slave_t *slave;
    ec_slave_ident_t *ident;
    ec_master_t *master = fsm->master;

    coupler_index = 0;
    reverse_coupler_index = 0xFFFF;
    current_coupler_index = 0x3FFF;
    coupler_subindex = 0;

    // for every slave on the bus
    list_for_each_entry(slave, &master->slaves, list)
    {
        // search for identification in "database"
        ident = slave_idents;
        while (ident->type) {
            if (unlikely(ident->vendor_id == slave->sii_vendor_id
                         && ident->product_code == slave->sii_product_code)) {
                slave->type = ident->type;
                break;
            }
            ident++;
        }

        if (!slave->type) {
            EC_WARN("FSM: Unknown slave device (vendor 0x%08X, code 0x%08X) at"
                    " position %i.\n", slave->sii_vendor_id,
                    slave->sii_product_code, slave->ring_position);
        }
        else if (slave->type->special == EC_TYPE_BUS_COUPLER) {
            if (slave->sii_alias)
                current_coupler_index = reverse_coupler_index--;
            else
                current_coupler_index = coupler_index++;
            coupler_subindex = 0;
        }

        slave->coupler_index = current_coupler_index;
        slave->coupler_subindex = coupler_subindex;
        coupler_subindex++;
    }

    fsm->master_state = ec_fsm_master_start;
    fsm->master_state(fsm); // execute immediately
}

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

/**
   Free-Run state: Finished.
   End state of the state machine. Does nothing.
*/

void ec_fsm_master_finished(ec_fsm_t *fsm)
{
}

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

/**
   Slave 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_start(ec_fsm_t *fsm)
{
    ec_command_t *command = &fsm->command;

    // write station address
    ec_command_apwr(command, fsm->slave->ring_position, 0x0010, 2);
    EC_WRITE_U16(command->data, fsm->slave->station_address);
    ec_master_queue_command(fsm->master, command);
    fsm->slave_state = ec_fsm_slave_read_base;
}

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

/**
   Slave state: Read base.
*/

void ec_fsm_slave_read_base(ec_fsm_t *fsm)
{
    ec_command_t *command = &fsm->command;

    if (command->state != EC_CMD_RECEIVED || command->working_counter != 1) {
        EC_ERR("FSM failed to write station address of slave %i.\n",
               fsm->slave->ring_position);
        fsm->slave_state = ec_fsm_slave_finished;
        return;
    }

    // read base data
    ec_command_nprd(command, fsm->slave->station_address, 0x0000, 6);
    ec_master_queue_command(fsm->master, command);
    fsm->slave_state = ec_fsm_slave_read_dl;
}

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

/**
   Slave state: Read DL.
*/

void ec_fsm_slave_read_dl(ec_fsm_t *fsm)
{
    ec_command_t *command = &fsm->command;
    ec_slave_t *slave = fsm->slave;

    if (command->state != EC_CMD_RECEIVED || command->working_counter != 1) {
        EC_ERR("FSM failed to read base data of slave %i.\n",
               slave->ring_position);
        fsm->slave_state = ec_fsm_slave_finished;
        return;
    }

    slave->base_type       = EC_READ_U8 (command->data);
    slave->base_revision   = EC_READ_U8 (command->data + 1);
    slave->base_build      = EC_READ_U16(command->data + 2);
    slave->base_fmmu_count = EC_READ_U8 (command->data + 4);
    slave->base_sync_count = EC_READ_U8 (command->data + 5);

    if (slave->base_fmmu_count > EC_MAX_FMMUS)
        slave->base_fmmu_count = EC_MAX_FMMUS;

    // read data link status
    ec_command_nprd(command, slave->station_address, 0x0110, 2);
    ec_master_queue_command(slave->master, command);
    fsm->slave_state = ec_fsm_slave_prepare_sii;
}

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

/**
   Slave state: Prepare SII.
*/

void ec_fsm_slave_prepare_sii(ec_fsm_t *fsm)
{
    ec_command_t *command = &fsm->command;
    ec_slave_t *slave = fsm->slave;
    uint16_t dl_status;
    unsigned int i;

    if (command->state != EC_CMD_RECEIVED || command->working_counter != 1) {
        EC_ERR("FSM failed to read DL status of slave %i.\n",
               slave->ring_position);
        fsm->slave_state = ec_fsm_slave_finished;
        return;
    }

    dl_status = EC_READ_U16(command->data);

    for (i = 0; i < 4; i++) {
        slave->dl_link[i] = dl_status & (1 << (4 + i)) ? 1 : 0;
        slave->dl_loop[i] = dl_status & (1 << (8 + i * 2)) ? 1 : 0;
        slave->dl_signal[i] = dl_status & (1 << (9 + i * 2)) ? 1 : 0;
    }

    fsm->sii_offset = 0x0004;
    fsm->sii_state = ec_fsm_sii_start_reading;
    fsm->slave_sii_num = 0;
    fsm->slave_state = ec_fsm_slave_read_sii;
    fsm->slave_state(fsm); // execute state immediately
}

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

/**
   Slave state: Read SII.
*/

void ec_fsm_slave_read_sii(ec_fsm_t *fsm)
{
    ec_slave_t *slave = fsm->slave;

    // execute SII state machine
    fsm->sii_state(fsm);

    if (fsm->sii_state == ec_fsm_sii_error) {
        fsm->slave_state = ec_fsm_slave_finished;
        EC_ERR("FSM failed to read SII data at 0x%04X on slave %i.\n",
               fsm->sii_offset, slave->ring_position);
        return;
    }

    if (fsm->sii_state != ec_fsm_sii_finished) return;

    switch (fsm->slave_sii_num) {
        case 0:
            slave->sii_alias = fsm->sii_result & 0xFFFF;
            fsm->sii_offset = 0x0008;
            break;
        case 1:
            slave->sii_vendor_id = fsm->sii_result;
            fsm->sii_offset = 0x000A;
            break;
        case 2:
            slave->sii_product_code = fsm->sii_result;
            fsm->sii_offset = 0x000C;
            break;
        case 3:
            slave->sii_revision_number = fsm->sii_result;
            fsm->sii_offset = 0x000E;
            break;
        case 4:
            slave->sii_serial_number = fsm->sii_result;
            fsm->sii_offset = 0x0018;
            break;
        case 5:
            slave->sii_rx_mailbox_offset = fsm->sii_result & 0xFFFF;
            slave->sii_rx_mailbox_size = fsm->sii_result >> 16;
            fsm->sii_offset = 0x001A;
            break;
        case 6:
            slave->sii_tx_mailbox_offset = fsm->sii_result & 0xFFFF;
            slave->sii_tx_mailbox_size = fsm->sii_result >> 16;
            fsm->sii_offset = 0x001C;
            break;
        case 7:
            slave->sii_mailbox_protocols = fsm->sii_result & 0xFFFF;
            fsm->slave_state = ec_fsm_slave_categories;
            fsm->slave_state(fsm); // execute state immediately
            return;
    }

    fsm->slave_sii_num++;
    fsm->sii_state = ec_fsm_sii_start_reading;
    fsm->slave_state(fsm); // execute state immediately
}

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

/**
   Slave state: Categories.
*/

void ec_fsm_slave_categories(ec_fsm_t *fsm)
{
    fsm->slave_cat_offset = 0x0040;

    if (fsm->slave_cat_data) {
        EC_INFO("FSM freeing old category data on slave %i...\n",
                fsm->slave->ring_position);
        kfree(fsm->slave_cat_data);
    }

    if (!(fsm->slave_cat_data = (uint8_t *) kmalloc(EC_CAT_MEM, GFP_ATOMIC))) {
        EC_ERR("FSM Failed to allocate category data.\n");
        fsm->slave_state = ec_fsm_slave_finished;
        return;
    }

    // start reading first category header
    fsm->sii_offset = fsm->slave_cat_offset;
    fsm->sii_state = ec_fsm_sii_start_reading;

    fsm->slave_state = ec_fsm_slave_category_header;
    fsm->slave_state(fsm); // execute state immediately
}

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

/**
   Slave state: Read categories.
   Start reading categories.
*/

void ec_fsm_slave_category_header(ec_fsm_t *fsm)
{
    // execute SII state machine
    fsm->sii_state(fsm);

    if (fsm->sii_state == ec_fsm_sii_error) {
        kfree(fsm->slave_cat_data);
        fsm->slave_cat_data = NULL;
        fsm->slave_state = ec_fsm_slave_finished;
        EC_ERR("FSM failed to read category header at 0x%04X on slave %i.\n",
               fsm->slave_cat_offset, fsm->slave->ring_position);
        return;
    }

    if (fsm->sii_state != ec_fsm_sii_finished) return;

    // last category?
    if ((fsm->sii_result & 0xFFFF) == 0xFFFF) {
        kfree(fsm->slave_cat_data);
        fsm->slave_cat_data = NULL;
        fsm->slave_state = ec_fsm_slave_finished;
        return;
    }

    fsm->slave_cat_type = fsm->sii_result & 0x7FFF;
    fsm->slave_cat_words = (fsm->sii_result >> 16) & 0xFFFF;

    if (fsm->slave_cat_words > EC_CAT_MEM * 2) {
        EC_ERR("FSM category memory too small! %i words needed.\n",
               fsm->slave_cat_words);
        fsm->slave_state = ec_fsm_slave_finished;
        return;
    }

    // start reading category data
    fsm->slave_cat_data_offset = 0;
    fsm->sii_offset = (fsm->slave_cat_offset + 2 +
                       fsm->slave_cat_data_offset);
    fsm->sii_state = ec_fsm_sii_start_reading;
    fsm->slave_state = ec_fsm_slave_category_data;
    fsm->slave_state(fsm); // execute state immediately
}

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

/**
   Slave state: Category data.
   Reads category data.
*/

void ec_fsm_slave_category_data(ec_fsm_t *fsm)
{
    // execute SII state machine
    fsm->sii_state(fsm);

    if (fsm->sii_state == ec_fsm_sii_error) {
        kfree(fsm->slave_cat_data);
        fsm->slave_cat_data = NULL;
        fsm->slave_state = ec_fsm_slave_finished;
        EC_ERR("FSM failed to read category 0x%02X data at 0x%04X"
               " on slave %i.\n", fsm->slave_cat_type, fsm->sii_offset,
               fsm->slave->ring_position);
        return;
    }

    if (fsm->sii_state != ec_fsm_sii_finished) return;

    fsm->slave_cat_data[fsm->slave_cat_data_offset * 2] =
        fsm->sii_result & 0xFF;
    fsm->slave_cat_data[fsm->slave_cat_data_offset * 2 + 1] =
        (fsm->sii_result >> 8) & 0xFF;

    // read second word "on the fly"
    if (fsm->slave_cat_data_offset + 1 < fsm->slave_cat_words) {
        fsm->slave_cat_data_offset++;
        fsm->slave_cat_data[fsm->slave_cat_data_offset * 2] =
            (fsm->sii_result >> 16) & 0xFF;
        fsm->slave_cat_data[fsm->slave_cat_data_offset * 2 + 1] =
            (fsm->sii_result >> 24) & 0xFF;
    }

    fsm->slave_cat_data_offset++;

    if (fsm->slave_cat_data_offset < fsm->slave_cat_words) {
        fsm->sii_offset = (fsm->slave_cat_offset + 2 +
                           fsm->slave_cat_data_offset);
        fsm->sii_state = ec_fsm_sii_start_reading;
        fsm->slave_state = ec_fsm_slave_category_data;
        fsm->slave_state(fsm); // execute state immediately
        return;
    }

    // category data complete
    switch (fsm->slave_cat_type)
    {
        case 0x000A:
            if (ec_slave_fetch_strings(fsm->slave, fsm->slave_cat_data))
                goto out_free;
            break;
        case 0x001E:
            if (ec_slave_fetch_general(fsm->slave, fsm->slave_cat_data))
                goto out_free;
            break;
        case 0x0028:
            break;
        case 0x0029:
            if (ec_slave_fetch_sync(fsm->slave, fsm->slave_cat_data,
                                    fsm->slave_cat_words))
                goto out_free;
            break;
        case 0x0032:
            if (ec_slave_fetch_pdo(fsm->slave, fsm->slave_cat_data,
                                   fsm->slave_cat_words,
                                   EC_TX_PDO))
                goto out_free;
            break;
        case 0x0033:
            if (ec_slave_fetch_pdo(fsm->slave, fsm->slave_cat_data,
                                   fsm->slave_cat_words,
                                   EC_RX_PDO))
                goto out_free;
            break;
        default:
            EC_WARN("FSM: Unknown category type 0x%04X in slave %i.\n",
                    fsm->slave_cat_type, fsm->slave->ring_position);
    }

    // start reading next category header
    fsm->slave_cat_offset += 2 + fsm->slave_cat_words;
    fsm->sii_offset = fsm->slave_cat_offset;
    fsm->sii_state = ec_fsm_sii_start_reading;
    fsm->slave_state = ec_fsm_slave_category_header;
    fsm->slave_state(fsm); // execute state immediately
    return;

 out_free:
    kfree(fsm->slave_cat_data);
    fsm->slave_cat_data = NULL;
    fsm->slave_state = ec_fsm_slave_finished;
}

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

/**
   Slave state: Finished.
   End state of the slave state machine.
*/

void ec_fsm_slave_finished(ec_fsm_t *fsm)
{
}

/******************************************************************************
 *  SII state machine
 *****************************************************************************/

/**
   Slave SII state: Start reading.
   Starts reading the slave information interface.
*/

void ec_fsm_sii_start_reading(ec_fsm_t *fsm)
{
    ec_command_t *command = &fsm->command;

    // initiate read operation
    ec_command_npwr(command, fsm->slave->station_address, 0x502, 6);
    EC_WRITE_U8 (command->data,     0x00); // read-only access
    EC_WRITE_U8 (command->data + 1, 0x01); // request read operation
    EC_WRITE_U32(command->data + 2, fsm->sii_offset);
    ec_master_queue_command(fsm->master, command);
    fsm->sii_state = ec_fsm_sii_check;
}

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

/**
   Slave SII state: Check.
   Checks, if the SII-read-command has been sent and issues a fetch command.
*/

void ec_fsm_sii_check(ec_fsm_t *fsm)
{
    ec_command_t *command = &fsm->command;

    if (command->state != EC_CMD_RECEIVED || command->working_counter != 1) {
        EC_ERR("FSM SII: Reception of check command failed.\n");
        fsm->sii_state = ec_fsm_sii_error;
        return;
    }

    ec_command_nprd(command, fsm->slave->station_address, 0x502, 10);
    ec_master_queue_command(fsm->master, command);
    fsm->sii_state = ec_fsm_sii_fetch;
}

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

/**
   Slave SII state: Fetch.
   Fetches the result of an SII-read command.
*/

void ec_fsm_sii_fetch(ec_fsm_t *fsm)
{
    ec_command_t *command = &fsm->command;

    if (command->state != EC_CMD_RECEIVED || command->working_counter != 1) {
        EC_ERR("FSM SII: Reception of fetch command failed.\n");
        fsm->sii_state = ec_fsm_sii_error;
        return;
    }

    // check "busy bit"
    if (likely((EC_READ_U8(command->data + 1) & 0x81) == 0)) {
        fsm->sii_result = EC_READ_U32(command->data + 6);
        fsm->sii_state = ec_fsm_sii_finished;
    }
}

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

/**
   Slave SII state: Finished.
   End state of the slave SII state machine.
*/

void ec_fsm_sii_finished(ec_fsm_t *fsm)
{
}

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

/**
   Slave SII state: Error.
   End state of the slave SII state machine.
*/

void ec_fsm_sii_error(ec_fsm_t *fsm)
{
}

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