/*
 * Copyright (C) 2003-2008 Takahiro Hirofuchi
 *
 * This 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 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/string.h>
#include <linux/module.h>

#include "usbip_common.h"
#include "stub.h"

#define DRIVER_AUTHOR "Takahiro Hirofuchi"
#define DRIVER_DESC "USB/IP Host Driver"

struct kmem_cache *stub_priv_cache;
/*
 * busid_tables defines matching busids that usbip can grab. A user can change
 * dynamically what device is locally used and what device is exported to a
 * remote host.
 */
#define MAX_BUSID 16
static struct bus_id_priv busid_table[MAX_BUSID];
static spinlock_t busid_table_lock;

static void init_busid_table(void)
{
        /*
         * This also sets the bus_table[i].status to
         * STUB_BUSID_OTHER, which is 0.
         */
        memset(busid_table, 0, sizeof(busid_table));

        spin_lock_init(&busid_table_lock);
}

/*
 * Find the index of the busid by name.
 * Must be called with busid_table_lock held.
 */
static int get_busid_idx(const char *busid)
{
        int i;
        int idx = -1;

        for (i = 0; i < MAX_BUSID; i++)
                if (busid_table[i].name[0])
                        if (!strncmp(busid_table[i].name, busid, BUSID_SIZE)) {
                                idx = i;
                                break;
                        }
        return idx;
}

struct bus_id_priv *get_busid_priv(const char *busid)
{
        int idx;
        struct bus_id_priv *bid = NULL;

        spin_lock(&busid_table_lock);
        idx = get_busid_idx(busid);
        if (idx >= 0)
                bid = &(busid_table[idx]);
        spin_unlock(&busid_table_lock);

        return bid;
}

static int add_match_busid(char *busid)
{
        int i;
        int ret = -1;

        spin_lock(&busid_table_lock);
        /* already registered? */
        if (get_busid_idx(busid) >= 0) {
                ret = 0;
                goto out;
        }

        for (i = 0; i < MAX_BUSID; i++)
                if (!busid_table[i].name[0]) {
                        strncpy(busid_table[i].name, busid, BUSID_SIZE);
                        if ((busid_table[i].status != STUB_BUSID_ALLOC) &&
                            (busid_table[i].status != STUB_BUSID_REMOV))
                                busid_table[i].status = STUB_BUSID_ADDED;
                        ret = 0;
                        break;
                }

out:
        spin_unlock(&busid_table_lock);

        return ret;
}

int del_match_busid(char *busid)
{
        int idx;
        int ret = -1;

        spin_lock(&busid_table_lock);
        idx = get_busid_idx(busid);
        if (idx < 0)
                goto out;

        /* found */
        ret = 0;

        if (busid_table[idx].status == STUB_BUSID_OTHER)
                memset(busid_table[idx].name, 0, BUSID_SIZE);

        if ((busid_table[idx].status != STUB_BUSID_OTHER) &&
            (busid_table[idx].status != STUB_BUSID_ADDED))
                busid_table[idx].status = STUB_BUSID_REMOV;

out:
        spin_unlock(&busid_table_lock);

        return ret;
}

static ssize_t show_match_busid(struct device_driver *drv, char *buf)
{
        int i;
        char *out = buf;

        spin_lock(&busid_table_lock);
        for (i = 0; i < MAX_BUSID; i++)
                if (busid_table[i].name[0])
                        out += sprintf(out, "%s ", busid_table[i].name);
        spin_unlock(&busid_table_lock);
        out += sprintf(out, "\n");

        return out - buf;
}

static ssize_t store_match_busid(struct device_driver *dev, const char *buf,
                                 size_t count)
{
        int len;
        char busid[BUSID_SIZE];

        if (count < 5)
                return -EINVAL;

        /* strnlen() does not include \0 */
        len = strnlen(buf + 4, BUSID_SIZE);

        /* busid needs to include \0 termination */
        if (!(len < BUSID_SIZE))
                return -EINVAL;

        strncpy(busid, buf + 4, BUSID_SIZE);

        if (!strncmp(buf, "add ", 4)) {
                if (add_match_busid(busid) < 0)
                        return -ENOMEM;

                pr_debug("add busid %s\n", busid);
                return count;
        }

        if (!strncmp(buf, "del ", 4)) {
                if (del_match_busid(busid) < 0)
                        return -ENODEV;

                pr_debug("del busid %s\n", busid);
                return count;
        }

        return -EINVAL;
}
static DRIVER_ATTR(match_busid, S_IRUSR | S_IWUSR, show_match_busid,
                   store_match_busid);

static struct stub_priv *stub_priv_pop_from_listhead(struct list_head *listhead)
{
        struct stub_priv *priv, *tmp;

        list_for_each_entry_safe(priv, tmp, listhead, list) {
                list_del(&priv->list);
                return priv;
        }

        return NULL;
}

static struct stub_priv *stub_priv_pop(struct stub_device *sdev)
{
        unsigned long flags;
        struct stub_priv *priv;

        spin_lock_irqsave(&sdev->priv_lock, flags);

        priv = stub_priv_pop_from_listhead(&sdev->priv_init);
        if (priv)
                goto done;

        priv = stub_priv_pop_from_listhead(&sdev->priv_tx);
        if (priv)
                goto done;

        priv = stub_priv_pop_from_listhead(&sdev->priv_free);

done:
        spin_unlock_irqrestore(&sdev->priv_lock, flags);

        return priv;
}

void stub_device_cleanup_urbs(struct stub_device *sdev)
{
        struct stub_priv *priv;
        struct urb *urb;

        dev_dbg(&sdev->udev->dev, "free sdev %p\n", sdev);

        while ((priv = stub_priv_pop(sdev))) {
                urb = priv->urb;
                dev_dbg(&sdev->udev->dev, "free urb %p\n", urb);
                usb_kill_urb(urb);

                kmem_cache_free(stub_priv_cache, priv);

                kfree(urb->transfer_buffer);
                kfree(urb->setup_packet);
                usb_free_urb(urb);
        }
}

static int __init usbip_host_init(void)
{
        int ret;

        init_busid_table();

        stub_priv_cache = KMEM_CACHE(stub_priv, SLAB_HWCACHE_ALIGN);
        if (!stub_priv_cache) {
                pr_err("kmem_cache_create failed\n");
                return -ENOMEM;
        }

        ret = usb_register(&stub_driver);
        if (ret < 0) {
                pr_err("usb_register failed %d\n", ret);
                goto err_usb_register;
        }

        ret = driver_create_file(&stub_driver.drvwrap.driver,
                                 &driver_attr_match_busid);
        if (ret < 0) {
                pr_err("driver_create_file failed\n");
                goto err_create_file;
        }

        pr_info(DRIVER_DESC " v" USBIP_VERSION "\n");
        return ret;

err_create_file:
        usb_deregister(&stub_driver);
err_usb_register:
        kmem_cache_destroy(stub_priv_cache);
        return ret;
}

static void __exit usbip_host_exit(void)
{
        driver_remove_file(&stub_driver.drvwrap.driver,
                           &driver_attr_match_busid);

        /*
         * deregister() calls stub_disconnect() for all devices. Device
         * specific data is cleared in stub_disconnect().
         */
        usb_deregister(&stub_driver);

        kmem_cache_destroy(stub_priv_cache);
}

module_init(usbip_host_init);
module_exit(usbip_host_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
MODULE_VERSION(USBIP_VERSION);