/*
 * 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 "usbip_common.h"
#include "stub.h"



static int stub_probe(struct usb_interface *interface,
                                const struct usb_device_id *id);
static void stub_disconnect(struct usb_interface *interface);


/*
 * Define device IDs here if you want to explicitly limit exportable devices.
 * In the most cases, wild card matching will be ok 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);

struct usb_driver stub_driver = {
        .name           = "usbip",
        .probe          = stub_probe,
        .disconnect     = stub_disconnect,
        .id_table       = stub_table,
};


/*-------------------------------------------------------------------------*/

/* Define sysfs entries for a usbip-bound device */


/*
 * usbip_status shows status of usbip 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);

                usbip_start_threads(&sdev->ud);

                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);
}



/*-------------------------------------------------------------------------*/

/* Event handler functions called by an event handler thread */

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) {
                usbip_udbg("shutdown tcp_socket %p\n", ud->tcp_socket);
                kernel_sock_shutdown(ud->tcp_socket, SHUT_RDWR);
        }

        /* 1. stop threads */
        usbip_stop_threads(ud);

        /* 2. close the socket */
        /*
         * tcp_socket is freed after threads are killed.
         * So usbip_xmit do 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 = interface_to_usbdev(sdev->interface);
        int ret;

        usbip_udbg("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);

        return;
}

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_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 = interface;

        /*
         * 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;

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

        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);

        usbip_udbg("register new interface\n");
        return sdev;
}

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

        kfree(sdev);
        usbip_udbg("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;

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

        /* check we should claim or not by busid_table */
        if (match_busid(udev_busid)) {
                dev_info(&interface->dev,
                         "this device %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) {
                usbip_udbg("this device %s is a usb hub device. skip!\n",
                                                                udev_busid);
                return -ENODEV;
        }

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

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

        dev_info(&interface->dev, "USB/IP Stub: register a 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, "create sysfs files for %s\n",
                        udev_busid);
                return err;
        }

        return 0;
}


/*
 * 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 = usb_get_intfdata(interface);

        usbip_udbg("Enter\n");

        /* get stub_device */
        if (!sdev) {
                err(" could not get device from inteface data");
                /* BUG(); */
                return;
        }

        usb_set_intfdata(interface, NULL);


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

        /* 1. shutdown the current connection */
        usbip_event_add(&sdev->ud, SDEV_EVENT_REMOVED);

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

        /* 3. free sdev */
        stub_device_free(sdev);


        usbip_udbg("bye\n");
}