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/*

 *      w1_int.c

 *

 * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>

 *

 *

 * This program 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.

 *

 * This program 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 this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

 */

#include <linux/kernel.h>

#include <linux/list.h>

#include <linux/delay.h>

#include <linux/kthread.h>

#include "w1.h"

#include "w1_log.h"

#include "w1_netlink.h"

#include "w1_int.h"

static u32 w1_ids = 1;

static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,

                                       struct device_driver *driver,

                                       struct device *device)

{

        struct w1_master *dev;

        int err;

        /*

         * We are in process context(kernel thread), so can sleep.

         */

        dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);

        if (!dev) {

                printk(KERN_ERR

                        "Failed to allocate %zd bytes for new w1 device.\n",

                        sizeof(struct w1_master));

                return NULL;

        }

        dev->bus_master = (struct w1_bus_master *)(dev + 1);

        dev->owner              = THIS_MODULE;

        dev->max_slave_count    = slave_count;

        dev->slave_count        = 0;

        dev->attempts           = 0;

        dev->initialized        = 0;

        dev->id                 = id;

        dev->slave_ttl          = slave_ttl;

        dev->search_count       = -1; /* continual scan */

        atomic_set(&dev->refcnt, 2);

        INIT_LIST_HEAD(&dev->slist);

        mutex_init(&dev->mutex);

        memcpy(&dev->dev, device, sizeof(struct device));

        snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id),

                  "w1_bus_master%u", dev->id);

        snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);

        dev->driver = driver;

        dev->seq = 1;

        err = device_register(&dev->dev);

        if (err) {

                printk(KERN_ERR "Failed to register master device. err=%d\n", err);

                memset(dev, 0, sizeof(struct w1_master));

                kfree(dev);

                dev = NULL;

        }

        return dev;

}

static void w1_free_dev(struct w1_master *dev)

{

        device_unregister(&dev->dev);

}

int w1_add_master_device(struct w1_bus_master *master)

{

        struct w1_master *dev;

        int retval = 0;

        struct w1_netlink_msg msg;

        /* validate minimum functionality */

        if (!(master->touch_bit && master->reset_bus) &&

            !(master->write_bit && master->read_bit) &&

            !(master->write_byte && master->read_byte && master->reset_bus)) {

                printk(KERN_ERR "w1_add_master_device: invalid function set\n");

                return(-EINVAL);

        }

        dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device);

        if (!dev)

                return -ENOMEM;

        dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);

        if (IS_ERR(dev->thread)) {

                retval = PTR_ERR(dev->thread);

                dev_err(&dev->dev,

                         "Failed to create new kernel thread. err=%d\n",

                         retval);

                goto err_out_free_dev;

        }

        retval =  w1_create_master_attributes(dev);

        if (retval)

                goto err_out_kill_thread;

        memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));

        dev->initialized = 1;

        mutex_lock(&w1_mlock);

        list_add(&dev->w1_master_entry, &w1_masters);

        mutex_unlock(&w1_mlock);

        memset(&msg, 0, sizeof(msg));

        msg.id.mst.id = dev->id;

        msg.type = W1_MASTER_ADD;

        w1_netlink_send(dev, &msg);

        return 0;

err_out_kill_thread:

        kthread_stop(dev->thread);

err_out_free_dev:

        w1_free_dev(dev);

        return retval;

}

void __w1_remove_master_device(struct w1_master *dev)

{

        struct w1_netlink_msg msg;

        set_bit(W1_MASTER_NEED_EXIT, &dev->flags);

        kthread_stop(dev->thread);

        while (atomic_read(&dev->refcnt)) {

                dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",

                                dev->name, atomic_read(&dev->refcnt));

                if (msleep_interruptible(1000))

                        flush_signals(current);

        }

        memset(&msg, 0, sizeof(msg));

        msg.id.mst.id = dev->id;

        msg.type = W1_MASTER_REMOVE;

        w1_netlink_send(dev, &msg);

        w1_free_dev(dev);

}

void w1_remove_master_device(struct w1_bus_master *bm)

{

        struct w1_master *dev, *found = NULL;

        list_for_each_entry(dev, &w1_masters, w1_master_entry) {

                if (!dev->initialized)

                        continue;

                if (dev->bus_master->data == bm->data) {

                        found = dev;

                        break;

                }

        }

        if (!found) {

                printk(KERN_ERR "Device doesn't exist.\n");

                return;

        }

        __w1_remove_master_device(found);

}

EXPORT_SYMBOL(w1_add_master_device);

EXPORT_SYMBOL(w1_remove_master_device);