/*
 * 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/device.h>
#include <linux/kthread.h>

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

/*
 * Define device IDs here if you want to explicitly limit exportable devices.
 * In most cases, wildcard matching will be okay because driver binding can be
 * changed dynamically by a userland program.
 */
static struct usb_device_id stub_table[] = {
#if 0
        /* just an example */
        { USB_DEVICE(0x05ac, 0x0301) },   /* Mac 1 button mouse */
        { USB_DEVICE(0x0430, 0x0009) },   /* Plat Home Keyboard */
        { USB_DEVICE(0x059b, 0x0001) },   /* Iomega USB Zip 100 */
        { USB_DEVICE(0x04b3, 0x4427) },   /* IBM USB CD-ROM */
        { USB_DEVICE(0x05a9, 0xa511) },   /* LifeView USB cam */
        { USB_DEVICE(0x55aa, 0x0201) },   /* Imation card reader */
        { USB_DEVICE(0x046d, 0x0870) },   /* Qcam Express(QV-30) */
        { USB_DEVICE(0x04bb, 0x0101) },   /* IO-DATA HD 120GB */
        { USB_DEVICE(0x04bb, 0x0904) },   /* IO-DATA USB-ET/TX */
        { USB_DEVICE(0x04bb, 0x0201) },   /* IO-DATA USB-ET/TX */
        { USB_DEVICE(0x08bb, 0x2702) },   /* ONKYO USB Speaker */
        { USB_DEVICE(0x046d, 0x08b2) },   /* Logicool Qcam 4000 Pro */
#endif
        /* magic for wild card */
        { .driver_info = 1 },
        { 0, }                                     /* Terminating entry */
};
MODULE_DEVICE_TABLE(usb, stub_table);

/*
 * usbip_status shows the status of usbip-host as long as this driver is bound
 * to the target device.
 */
static ssize_t show_status(struct device *dev, struct device_attribute *attr,
                           char *buf)
{
        struct stub_device *sdev = dev_get_drvdata(dev);
        int status;

        if (!sdev) {
                dev_err(dev, "sdev is null\n");
                return -ENODEV;
        }

        spin_lock(&sdev->ud.lock);
        status = sdev->ud.status;
        spin_unlock(&sdev->ud.lock);

        return snprintf(buf, PAGE_SIZE, "%d\n", status);
}
static DEVICE_ATTR(usbip_status, S_IRUGO, show_status, NULL);

/*
 * usbip_sockfd gets a socket descriptor of an established TCP connection that
 * is used to transfer usbip requests by kernel threads. -1 is a magic number
 * by which usbip connection is finished.
 */
static ssize_t store_sockfd(struct device *dev, struct device_attribute *attr,
                            const char *buf, size_t count)
{
        struct stub_device *sdev = dev_get_drvdata(dev);
        int sockfd = 0;
        struct socket *socket;

        if (!sdev) {
                dev_err(dev, "sdev is null\n");
                return -ENODEV;
        }

        sscanf(buf, "%d", &sockfd);

        if (sockfd != -1) {
                dev_info(dev, "stub up\n");

                spin_lock(&sdev->ud.lock);

                if (sdev->ud.status != SDEV_ST_AVAILABLE) {
                        dev_err(dev, "not ready\n");
                        spin_unlock(&sdev->ud.lock);
                        return -EINVAL;
                }

                socket = sockfd_to_socket(sockfd);
                if (!socket) {
                        spin_unlock(&sdev->ud.lock);
                        return -EINVAL;
                }
#if 0
                setnodelay(socket);
                setkeepalive(socket);
                setreuse(socket);
#endif
                sdev->ud.tcp_socket = socket;

                spin_unlock(&sdev->ud.lock);

                sdev->ud.tcp_rx = kthread_run(stub_rx_loop, &sdev->ud, "stub_rx");
                sdev->ud.tcp_tx = kthread_run(stub_tx_loop, &sdev->ud, "stub_tx");

                spin_lock(&sdev->ud.lock);
                sdev->ud.status = SDEV_ST_USED;
                spin_unlock(&sdev->ud.lock);

        } else {
                dev_info(dev, "stub down\n");

                spin_lock(&sdev->ud.lock);
                if (sdev->ud.status != SDEV_ST_USED) {
                        spin_unlock(&sdev->ud.lock);
                        return -EINVAL;
                }
                spin_unlock(&sdev->ud.lock);

                usbip_event_add(&sdev->ud, SDEV_EVENT_DOWN);
        }

        return count;
}
static DEVICE_ATTR(usbip_sockfd, S_IWUSR, NULL, store_sockfd);

static int stub_add_files(struct device *dev)
{
        int err = 0;

        err = device_create_file(dev, &dev_attr_usbip_status);
        if (err)
                goto err_status;

        err = device_create_file(dev, &dev_attr_usbip_sockfd);
        if (err)
                goto err_sockfd;

        err = device_create_file(dev, &dev_attr_usbip_debug);
        if (err)
                goto err_debug;

        return 0;

err_debug:
        device_remove_file(dev, &dev_attr_usbip_sockfd);
err_sockfd:
        device_remove_file(dev, &dev_attr_usbip_status);
err_status:
        return err;
}

static void stub_remove_files(struct device *dev)
{
        device_remove_file(dev, &dev_attr_usbip_status);
        device_remove_file(dev, &dev_attr_usbip_sockfd);
        device_remove_file(dev, &dev_attr_usbip_debug);
}

static void stub_shutdown_connection(struct usbip_device *ud)
{
        struct stub_device *sdev = container_of(ud, struct stub_device, ud);

        /*
         * When removing an exported device, kernel panic sometimes occurred
         * and then EIP was sk_wait_data of stub_rx thread. Is this because
         * sk_wait_data returned though stub_rx thread was already finished by
         * step 1?
         */
        if (ud->tcp_socket) {
                dev_dbg(&sdev->udev->dev, "shutdown tcp_socket %p\n",
                        ud->tcp_socket);
                kernel_sock_shutdown(ud->tcp_socket, SHUT_RDWR);
        }

        /* 1. stop threads */
        if (ud->tcp_rx && !task_is_dead(ud->tcp_rx))
                kthread_stop(ud->tcp_rx);
        if (ud->tcp_tx && !task_is_dead(ud->tcp_tx))
                kthread_stop(ud->tcp_tx);

        /*
         * 2. close the socket
         *
         * tcp_socket is freed after threads are killed so that usbip_xmit does
         * not touch NULL socket.
         */
        if (ud->tcp_socket) {
                sock_release(ud->tcp_socket);
                ud->tcp_socket = NULL;
        }

        /* 3. free used data */
        stub_device_cleanup_urbs(sdev);

        /* 4. free stub_unlink */
        {
                unsigned long flags;
                struct stub_unlink *unlink, *tmp;

                spin_lock_irqsave(&sdev->priv_lock, flags);
                list_for_each_entry_safe(unlink, tmp, &sdev->unlink_tx, list) {
                        list_del(&unlink->list);
                        kfree(unlink);
                }
                list_for_each_entry_safe(unlink, tmp, &sdev->unlink_free,
                                         list) {
                        list_del(&unlink->list);
                        kfree(unlink);
                }
                spin_unlock_irqrestore(&sdev->priv_lock, flags);
        }
}

static void stub_device_reset(struct usbip_device *ud)
{
        struct stub_device *sdev = container_of(ud, struct stub_device, ud);
        struct usb_device *udev = sdev->udev;
        int ret;

        dev_dbg(&udev->dev, "device reset");

        ret = usb_lock_device_for_reset(udev, sdev->interface);
        if (ret < 0) {
                dev_err(&udev->dev, "lock for reset\n");
                spin_lock(&ud->lock);
                ud->status = SDEV_ST_ERROR;
                spin_unlock(&ud->lock);
                return;
        }

        /* try to reset the device */
        ret = usb_reset_device(udev);
        usb_unlock_device(udev);

        spin_lock(&ud->lock);
        if (ret) {
                dev_err(&udev->dev, "device reset\n");
                ud->status = SDEV_ST_ERROR;
        } else {
                dev_info(&udev->dev, "device reset\n");
                ud->status = SDEV_ST_AVAILABLE;
        }
        spin_unlock(&ud->lock);
}

static void stub_device_unusable(struct usbip_device *ud)
{
        spin_lock(&ud->lock);
        ud->status = SDEV_ST_ERROR;
        spin_unlock(&ud->lock);
}

/**
 * stub_device_alloc - allocate a new stub_device struct
 * @interface: usb_interface of a new device
 *
 * Allocates and initializes a new stub_device struct.
 */
static struct stub_device *stub_device_alloc(struct usb_device *udev,
                                             struct usb_interface *interface)
{
        struct stub_device *sdev;
        int busnum = interface_to_busnum(interface);
        int devnum = interface_to_devnum(interface);

        dev_dbg(&interface->dev, "allocating stub device");

        /* yes, it's a new device */
        sdev = kzalloc(sizeof(struct stub_device), GFP_KERNEL);
        if (!sdev) {
                dev_err(&interface->dev, "no memory for stub_device\n");
                return NULL;
        }

        sdev->interface = usb_get_intf(interface);
        sdev->udev = usb_get_dev(udev);

        /*
         * devid is defined with devnum when this driver is first allocated.
         * devnum may change later if a device is reset. However, devid never
         * changes during a usbip connection.
         */
        sdev->devid             = (busnum << 16) | devnum;
        sdev->ud.side           = USBIP_STUB;
        sdev->ud.status         = SDEV_ST_AVAILABLE;
        /* sdev->ud.lock = SPIN_LOCK_UNLOCKED; */
        spin_lock_init(&sdev->ud.lock);
        sdev->ud.tcp_socket     = NULL;

        INIT_LIST_HEAD(&sdev->priv_init);
        INIT_LIST_HEAD(&sdev->priv_tx);
        INIT_LIST_HEAD(&sdev->priv_free);
        INIT_LIST_HEAD(&sdev->unlink_free);
        INIT_LIST_HEAD(&sdev->unlink_tx);
        /* sdev->priv_lock = SPIN_LOCK_UNLOCKED; */
        spin_lock_init(&sdev->priv_lock);

        init_waitqueue_head(&sdev->tx_waitq);

        sdev->ud.eh_ops.shutdown = stub_shutdown_connection;
        sdev->ud.eh_ops.reset    = stub_device_reset;
        sdev->ud.eh_ops.unusable = stub_device_unusable;

        usbip_start_eh(&sdev->ud);

        dev_dbg(&interface->dev, "register new interface\n");

        return sdev;
}

static int stub_device_free(struct stub_device *sdev)
{
        if (!sdev)
                return -EINVAL;

        kfree(sdev);
        pr_debug("kfree udev ok\n");

        return 0;
}

/*
 * If a usb device has multiple active interfaces, this driver is bound to all
 * the active interfaces. However, usbip exports *a* usb device (i.e., not *an*
 * active interface). Currently, a userland program must ensure that it
 * looks at the usbip's sysfs entries of only the first active interface.
 *
 * TODO: use "struct usb_device_driver" to bind a usb device.
 * However, it seems it is not fully supported in mainline kernel yet
 * (2.6.19.2).
 */
static int stub_probe(struct usb_interface *interface,
                      const struct usb_device_id *id)
{
        struct usb_device *udev = interface_to_usbdev(interface);
        struct stub_device *sdev = NULL;
        const char *udev_busid = dev_name(interface->dev.parent);
        int err = 0;
        struct bus_id_priv *busid_priv;

        dev_dbg(&interface->dev, "Enter\n");

        /* check we should claim or not by busid_table */
        busid_priv = get_busid_priv(udev_busid);
        if (!busid_priv || (busid_priv->status == STUB_BUSID_REMOV) ||
            (busid_priv->status == STUB_BUSID_OTHER)) {
                dev_info(&interface->dev, "%s is not in match_busid table... "
                         "skip!\n", udev_busid);

                /*
                 * Return value should be ENODEV or ENOXIO to continue trying
                 * other matched drivers by the driver core.
                 * See driver_probe_device() in driver/base/dd.c
                 */
                return -ENODEV;
        }

        if (udev->descriptor.bDeviceClass == USB_CLASS_HUB) {
                dev_dbg(&udev->dev, "%s is a usb hub device... skip!\n",
                         udev_busid);
                return -ENODEV;
        }

        if (!strcmp(udev->bus->bus_name, "vhci_hcd")) {
                dev_dbg(&udev->dev, "%s is attached on vhci_hcd... skip!\n",
                         udev_busid);
                return -ENODEV;
        }

        if (busid_priv->status == STUB_BUSID_ALLOC) {
                sdev = busid_priv->sdev;
                if (!sdev)
                        return -ENODEV;

                busid_priv->interf_count++;
                dev_info(&interface->dev, "usbip-host: register new interface "
                         "(bus %u dev %u ifn %u)\n",
                         udev->bus->busnum, udev->devnum,
                         interface->cur_altsetting->desc.bInterfaceNumber);

                /* set private data to usb_interface */
                usb_set_intfdata(interface, sdev);

                err = stub_add_files(&interface->dev);
                if (err) {
                        dev_err(&interface->dev, "stub_add_files for %s\n",
                                udev_busid);
                        usb_set_intfdata(interface, NULL);
                        busid_priv->interf_count--;
                        return err;
                }

                usb_get_intf(interface);
                return 0;
        }

        /* ok, this is my device */
        sdev = stub_device_alloc(udev, interface);
        if (!sdev)
                return -ENOMEM;

        dev_info(&interface->dev, "usbip-host: register new device "
                 "(bus %u dev %u ifn %u)\n", udev->bus->busnum, udev->devnum,
                 interface->cur_altsetting->desc.bInterfaceNumber);

        busid_priv->interf_count = 0;
        busid_priv->shutdown_busid = 0;

        /* set private data to usb_interface */
        usb_set_intfdata(interface, sdev);
        busid_priv->interf_count++;
        busid_priv->sdev = sdev;

        err = stub_add_files(&interface->dev);
        if (err) {
                dev_err(&interface->dev, "stub_add_files for %s\n", udev_busid);
                usb_set_intfdata(interface, NULL);
                usb_put_intf(interface);

                busid_priv->interf_count = 0;
                busid_priv->sdev = NULL;
                stub_device_free(sdev);
                return err;
        }
        busid_priv->status = STUB_BUSID_ALLOC;

        return 0;
}

static void shutdown_busid(struct bus_id_priv *busid_priv)
{
        if (busid_priv->sdev && !busid_priv->shutdown_busid) {
                busid_priv->shutdown_busid = 1;
                usbip_event_add(&busid_priv->sdev->ud, SDEV_EVENT_REMOVED);

                /* 2. wait for the stop of the event handler */
                usbip_stop_eh(&busid_priv->sdev->ud);
        }
}

/*
 * called in usb_disconnect() or usb_deregister()
 * but only if actconfig(active configuration) exists
 */
static void stub_disconnect(struct usb_interface *interface)
{
        struct stub_device *sdev;
        const char *udev_busid = dev_name(interface->dev.parent);
        struct bus_id_priv *busid_priv;

        dev_dbg(&interface->dev, "Enter\n");

        busid_priv = get_busid_priv(udev_busid);
        if (!busid_priv) {
                BUG();
                return;
        }

        sdev = usb_get_intfdata(interface);

        /* get stub_device */
        if (!sdev) {
                dev_err(&interface->dev, "could not get device");
                /* BUG(); */
                return;
        }

        usb_set_intfdata(interface, NULL);

        /*
         * NOTE:
         * rx/tx threads are invoked for each usb_device.
         */
        stub_remove_files(&interface->dev);

        /*If usb reset called from event handler*/
        if (busid_priv->sdev->ud.eh == current) {
                busid_priv->interf_count--;
                return;
        }

        if (busid_priv->interf_count > 1) {
                busid_priv->interf_count--;
                shutdown_busid(busid_priv);
                usb_put_intf(interface);
                return;
        }

        busid_priv->interf_count = 0;

        /* 1. shutdown the current connection */
        shutdown_busid(busid_priv);

        usb_put_dev(sdev->udev);
        usb_put_intf(interface);

        /* 3. free sdev */
        busid_priv->sdev = NULL;
        stub_device_free(sdev);

        if (busid_priv->status == STUB_BUSID_ALLOC) {
                busid_priv->status = STUB_BUSID_ADDED;
        } else {
                busid_priv->status = STUB_BUSID_OTHER;
                del_match_busid((char *)udev_busid);
        }
}

/* 
 * Presence of pre_reset and post_reset prevents the driver from being unbound
 * when the device is being reset
 */
 
int stub_pre_reset(struct usb_interface *interface)
{
        dev_dbg(&interface->dev, "pre_reset\n");
        return 0;
}

int stub_post_reset(struct usb_interface *interface)
{
        dev_dbg(&interface->dev, "post_reset\n");
        return 0;
}

struct usb_driver stub_driver = {
        .name           = "usbip-host",
        .probe          = stub_probe,
        .disconnect     = stub_disconnect,
        .id_table       = stub_table,
        .pre_reset      = stub_pre_reset,
        .post_reset     = stub_post_reset,
 };