/******************************************************************************
 *
 *  $Id$
 *
 *  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
 *
 *  Using the EtherCAT technology and brand is permitted in compliance with
 *  the industrial property and similar rights of Beckhoff Automation GmbH.
 *
 *****************************************************************************/

/** \file
 * EtherCAT master driver module.
 */

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

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

#include "globals.h"
#include "master.h"
#include "device.h"

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

#define MAX_MASTERS 5 /**< Maximum number of masters. */

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

int __init ec_init_module(void);
void __exit ec_cleanup_module(void);

static int ec_mac_parse(uint8_t *, const char *, int);

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

static char *main_devices[MAX_MASTERS]; /**< Main devices parameter. */
static char *backup_devices[MAX_MASTERS]; /**< Backup devices parameter. */

static ec_master_t *masters; /**< Array of masters. */
static struct semaphore master_sem; /**< Master semaphore. */
static unsigned int master_count; /**< Number of masters. */
static unsigned int backup_count; /**< Number of backup devices. */

dev_t device_number; /**< Device number for master cdevs. */
struct class *class; /**< Device class. */

static uint8_t macs[MAX_MASTERS][2][ETH_ALEN]; /**< MAC addresses. */

char *ec_master_version_str = EC_MASTER_VERSION; /**< Version string. */

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

/** \cond */

MODULE_AUTHOR("Florian Pose <fp@igh-essen.com>");
MODULE_DESCRIPTION("EtherCAT master driver module");
MODULE_LICENSE("GPL");
MODULE_VERSION(EC_MASTER_VERSION);

module_param_array(main_devices, charp, &master_count, S_IRUGO);
MODULE_PARM_DESC(main_devices, "MAC addresses of main devices");
module_param_array(backup_devices, charp, &backup_count, S_IRUGO);
MODULE_PARM_DESC(backup_devices, "MAC addresses of backup devices");

/** \endcond */

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

/** Module initialization.
 *
 * Initializes \a master_count masters.
 * \return 0 on success, else < 0
 */
int __init ec_init_module(void)
{
    int i, ret = 0;

    EC_INFO("Master driver %s\n", EC_MASTER_VERSION);

    init_MUTEX(&master_sem);

    if (master_count) {
        if (alloc_chrdev_region(&device_number, 0, master_count, "EtherCAT")) {
            EC_ERR("Failed to obtain device number(s)!\n");
            ret = -EBUSY;
            goto out_return;
        }
    }

    class = class_create(THIS_MODULE, "EtherCAT");
    if (IS_ERR(class)) {
        EC_ERR("Failed to create device class.\n");
        goto out_cdev;
    }

    // zero MAC addresses
    memset(macs, 0x00, sizeof(uint8_t) * MAX_MASTERS * 2 * ETH_ALEN);

    // process MAC parameters
    for (i = 0; i < master_count; i++) {
        if (ec_mac_parse(macs[i][0], main_devices[i], 0)) {
            ret = -EINVAL;
            goto out_class;
        }
        
        if (i < backup_count && ec_mac_parse(macs[i][1], backup_devices[i], 1)) {
            ret = -EINVAL;
            goto out_class;
        }
    }

    // initialize static master variables
    ec_master_init_static();
    
    if (master_count) {
        if (!(masters = kmalloc(sizeof(ec_master_t) * master_count,
                        GFP_KERNEL))) {
            EC_ERR("Failed to allocate memory for EtherCAT masters.\n");
            ret = -ENOMEM;
            goto out_class;
        }
    }
    
    for (i = 0; i < master_count; i++) {
        if (ec_master_init(&masters[i], i, macs[i][0], macs[i][1],
                    device_number, class)) {
            ret = -ENOMEM;
            goto out_free_masters;
        }
    }
    
    EC_INFO("%u master%s waiting for devices.\n",
            master_count, (master_count == 1 ? "" : "s"));
    return ret;

out_free_masters:
    for (i--; i >= 0; i--)
        ec_master_clear(&masters[i]);
    kfree(masters);
out_class:
    class_destroy(class);
out_cdev:
    if (master_count)
        unregister_chrdev_region(device_number, master_count);
out_return:
    return ret;
}

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

/** Module cleanup.
 *
 * Clears all master instances.
 */
void __exit ec_cleanup_module(void)
{
    unsigned int i;

    for (i = 0; i < master_count; i++) {
        ec_master_clear(&masters[i]);
    }

    if (master_count)
        kfree(masters);
    
    class_destroy(class);
    
    if (master_count)
        unregister_chrdev_region(device_number, master_count);
    
    EC_INFO("Master module cleaned up.\n");
}

/*****************************************************************************
 * MAC address functions
 ****************************************************************************/

/**
 * \return true, if two MAC addresses are equal.
 */
int ec_mac_equal(
        const uint8_t *mac1, /**< First MAC address. */
        const uint8_t *mac2 /**< Second MAC address. */
        )
{
    unsigned int i;
    
    for (i = 0; i < ETH_ALEN; i++)
        if (mac1[i] != mac2[i])
            return 0;

    return 1;
}
                
/*****************************************************************************/

/** Print a MAC address to a buffer.
 *
 * \return number of bytes written.
 */
ssize_t ec_mac_print(
        const uint8_t *mac, /**< MAC address */
        char *buffer /**< target buffer */
        )
{
    off_t off = 0;
    unsigned int i;
    
    for (i = 0; i < ETH_ALEN; i++) {
        off += sprintf(buffer + off, "%02X", mac[i]);
        if (i < ETH_ALEN - 1) off += sprintf(buffer + off, ":");
    }

    return off;
}

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

/**
 * \return true, if the MAC address is all-zero.
 */
int ec_mac_is_zero(
        const uint8_t *mac /**< MAC address. */
        )
{
    unsigned int i;
    
    for (i = 0; i < ETH_ALEN; i++)
        if (mac[i])
            return 0;

    return 1;
}

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

/**
 * \return true, if the given MAC address is the broadcast address.
 */
int ec_mac_is_broadcast(
        const uint8_t *mac /**< MAC address. */
        )
{
    unsigned int i;
    
    for (i = 0; i < ETH_ALEN; i++)
        if (mac[i] != 0xff)
            return 0;

    return 1;
}

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

/** Parse a MAC address from a string.
 *
 * The MAC address must follow the regexp
 * "([0-9a-fA-F]{2}:){5}[0-9a-fA-F]{2}".
 *
 * \return 0 on success, else < 0
 */
static int ec_mac_parse(uint8_t *mac, const char *src, int allow_empty)
{
    unsigned int i, value;
    const char *orig = src;
    char *rem;

    if (!strlen(src)) {
        if (allow_empty){
            return 0;
        }
        else {
            EC_ERR("MAC address may not be empty.\n");
            return -EINVAL;
        }
    }

    for (i = 0; i < ETH_ALEN; i++) {
        value = simple_strtoul(src, &rem, 16);
        if (rem != src + 2
                || value > 0xFF
                || (i < ETH_ALEN - 1 && *rem != ':')) {
            EC_ERR("Invalid MAC address \"%s\".\n", orig);
            return -EINVAL;
        }
        mac[i] = value;
        if (i < ETH_ALEN - 1)
            src = rem + 1; // skip colon
    }

    return 0;
}

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

/** Outputs frame contents for debugging purposes.
 */
void ec_print_data(const uint8_t *data, /**< pointer to data */
                   size_t size /**< number of bytes to output */
                   )
{
    unsigned int i;

    EC_DBG("");
    for (i = 0; i < size; i++) {
        printk("%02X ", data[i]);
        if ((i + 1) % 16 == 0) {
            printk("\n");
            EC_DBG("");
        }
    }
    printk("\n");
}

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

/** Outputs frame contents and differences for debugging purposes.
 */
void ec_print_data_diff(const uint8_t *d1, /**< first data */
                        const uint8_t *d2, /**< second data */
                        size_t size /** number of bytes to output */
                        )
{
    unsigned int i;

    EC_DBG("");
    for (i = 0; i < size; i++) {
        if (d1[i] == d2[i]) printk(".. ");
        else printk("%02X ", d2[i]);
        if ((i + 1) % 16 == 0) {
            printk("\n");
            EC_DBG("");
        }
    }
    printk("\n");
}

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

/** Prints slave states in clear text.
 */
size_t ec_state_string(uint8_t states, /**< slave states */
                       char *buffer /**< target buffer
                                       (min. EC_STATE_STRING_SIZE bytes) */
                       )
{
    off_t off = 0;
    unsigned int first = 1;

    if (!states) {
        off += sprintf(buffer + off, "(unknown)");
        return off;
    }

    if (states & EC_SLAVE_STATE_INIT) {
        off += sprintf(buffer + off, "INIT");
        first = 0;
    }
    if (states & EC_SLAVE_STATE_PREOP) {
        if (!first) off += sprintf(buffer + off, ", ");
        off += sprintf(buffer + off, "PREOP");
        first = 0;
    }
    if (states & EC_SLAVE_STATE_SAFEOP) {
        if (!first) off += sprintf(buffer + off, ", ");
        off += sprintf(buffer + off, "SAFEOP");
        first = 0;
    }
    if (states & EC_SLAVE_STATE_OP) {
        if (!first) off += sprintf(buffer + off, ", ");
        off += sprintf(buffer + off, "OP");
    }
    if (states & EC_SLAVE_STATE_ACK_ERR) {
        if (!first) off += sprintf(buffer + off, " + ");
        off += sprintf(buffer + off, "ERROR");
    }

    return off;
}

/******************************************************************************
 *  Device interface
 *****************************************************************************/

/** Offers an EtherCAT device to a certain master.
 *
 * The master decides, if it wants to use the device for EtherCAT operation,
 * or not. It is important, that the offered net_device is not used by the
 * kernel IP stack. If the master, accepted the offer, the address of the
 * newly created EtherCAT device is returned, else \a NULL is returned.
 *
 * \return Pointer to device, if accepted, or NULL if declined.
 * \ingroup DeviceInterface
 */
ec_device_t *ecdev_offer(
        struct net_device *net_dev, /**< net_device to offer */
        ec_pollfunc_t poll, /**< device poll function */
        struct module *module /**< pointer to the module */
        )
{
    ec_master_t *master;
    char str[20];
    unsigned int i;

    for (i = 0; i < master_count; i++) {
        master = &masters[i];

        down(&master->device_sem);
        if (master->main_device.dev) { // master already has a device
            up(&master->device_sem);
            continue;
        }
            
        if (ec_mac_equal(master->main_mac, net_dev->dev_addr)
                || ec_mac_is_broadcast(master->main_mac)) {
            ec_mac_print(net_dev->dev_addr, str);
            EC_INFO("Accepting device %s for master %u.\n",
                    str, master->index);

            ec_device_attach(&master->main_device, net_dev, poll, module);
            up(&master->device_sem);
            
            sprintf(net_dev->name, "ec%u", master->index);
            return &master->main_device; // offer accepted
        }
        else {
            up(&master->device_sem);

            if (master->debug_level) {
                ec_mac_print(net_dev->dev_addr, str);
                EC_DBG("Master %u declined device %s.\n", master->index, str);
            }
        }
    }

    return NULL; // offer declined
}

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

ec_master_t *ecrt_request_master(unsigned int master_index)
{
    ec_master_t *master;

    EC_INFO("Requesting master %u...\n", master_index);

    if (master_index >= master_count) {
        EC_ERR("Invalid master index %u.\n", master_index);
        goto out_return;
    }
    master = &masters[master_index];

    if (down_interruptible(&master_sem))
        goto out_return;

    if (master->reserved) {
        up(&master_sem);
        EC_ERR("Master %u is already in use!\n", master_index);
        goto out_return;
    }
    master->reserved = 1;
    up(&master_sem);

    if (down_interruptible(&master->device_sem))
        goto out_release;
    
    if (master->phase != EC_IDLE) {
        up(&master->device_sem);
        EC_ERR("Master %u still waiting for devices!\n", master_index);
        goto out_release;
    }

    if (!try_module_get(master->main_device.module)) {
        up(&master->device_sem);
        EC_ERR("Device module is unloading!\n");
        goto out_release;
    }

    up(&master->device_sem);

    if (ec_master_enter_operation_phase(master)) {
        EC_ERR("Failed to enter OPERATION phase!\n");
        goto out_module_put;
    }

    EC_INFO("Successfully requested master %u.\n", master_index);
    return master;

 out_module_put:
    module_put(master->main_device.module);
 out_release:
    master->reserved = 0;
 out_return:
    return NULL;
}

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

void ecrt_release_master(ec_master_t *master)
{
    EC_INFO("Releasing master %u...\n", master->index);

    if (!master->reserved) {
        EC_WARN("Master %u was was not requested!\n", master->index);
        return;
    }

    ec_master_leave_operation_phase(master);

    module_put(master->main_device.module);
    master->reserved = 0;

    EC_INFO("Released master %u.\n", master->index);
}

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

unsigned int ecrt_version_magic(void)
{
    return ECRT_VERSION_MAGIC;
}

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

/** \cond */

module_init(ec_init_module);
module_exit(ec_cleanup_module);

EXPORT_SYMBOL(ecdev_offer);

EXPORT_SYMBOL(ecrt_request_master);
EXPORT_SYMBOL(ecrt_release_master);
EXPORT_SYMBOL(ecrt_version_magic);

/** \endcond */

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