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

#include "usbip_common.h"
#include "vhci.h"

static void setup_cmd_submit_pdu(struct usbip_header *pdup,  struct urb *urb)
{
        struct vhci_priv *priv = ((struct vhci_priv *)urb->hcpriv);
        struct vhci_device *vdev = priv->vdev;

        usbip_dbg_vhci_tx("URB, local devnum %u, remote devid %u\n",
                          usb_pipedevice(urb->pipe), vdev->devid);

        pdup->base.command   = USBIP_CMD_SUBMIT;
        pdup->base.seqnum    = priv->seqnum;
        pdup->base.devid     = vdev->devid;
        pdup->base.direction = usb_pipein(urb->pipe) ?
                USBIP_DIR_IN : USBIP_DIR_OUT;
        pdup->base.ep        = usb_pipeendpoint(urb->pipe);

        usbip_pack_pdu(pdup, urb, USBIP_CMD_SUBMIT, 1);

        if (urb->setup_packet)
                memcpy(pdup->u.cmd_submit.setup, urb->setup_packet, 8);
}

static struct vhci_priv *dequeue_from_priv_tx(struct vhci_device *vdev)
{
        struct vhci_priv *priv, *tmp;
        unsigned long flags;

        spin_lock_irqsave(&vdev->priv_lock, flags);

        list_for_each_entry_safe(priv, tmp, &vdev->priv_tx, list) {
                list_move_tail(&priv->list, &vdev->priv_rx);
                spin_unlock_irqrestore(&vdev->priv_lock, flags);
                return priv;
        }

        spin_unlock_irqrestore(&vdev->priv_lock, flags);

        return NULL;
}

static int vhci_send_cmd_submit(struct vhci_device *vdev)
{
        struct vhci_priv *priv = NULL;

        struct msghdr msg;
        struct kvec iov[3];
        size_t txsize;

        size_t total_size = 0;

        while ((priv = dequeue_from_priv_tx(vdev)) != NULL) {
                int ret;
                struct urb *urb = priv->urb;
                struct usbip_header pdu_header;
                struct usbip_iso_packet_descriptor *iso_buffer = NULL;

                txsize = 0;
                memset(&pdu_header, 0, sizeof(pdu_header));
                memset(&msg, 0, sizeof(msg));
                memset(&iov, 0, sizeof(iov));

                usbip_dbg_vhci_tx("setup txdata urb %p\n", urb);

                /* 1. setup usbip_header */
                setup_cmd_submit_pdu(&pdu_header, urb);
                usbip_header_correct_endian(&pdu_header, 1);

                iov[0].iov_base = &pdu_header;
                iov[0].iov_len  = sizeof(pdu_header);
                txsize += sizeof(pdu_header);

                /* 2. setup transfer buffer */
                if (!usb_pipein(urb->pipe) && urb->transfer_buffer_length > 0) {
                        iov[1].iov_base = urb->transfer_buffer;
                        iov[1].iov_len  = urb->transfer_buffer_length;
                        txsize += urb->transfer_buffer_length;
                }

                /* 3. setup iso_packet_descriptor */
                if (usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS) {
                        ssize_t len = 0;

                        iso_buffer = usbip_alloc_iso_desc_pdu(urb, &len);
                        if (!iso_buffer) {
                                usbip_event_add(&vdev->ud,
                                                SDEV_EVENT_ERROR_MALLOC);
                                return -1;
                        }

                        iov[2].iov_base = iso_buffer;
                        iov[2].iov_len  = len;
                        txsize += len;
                }

                ret = kernel_sendmsg(vdev->ud.tcp_socket, &msg, iov, 3, txsize);
                if (ret != txsize) {
                        pr_err("sendmsg failed!, ret=%d for %zd\n", ret,
                               txsize);
                        kfree(iso_buffer);
                        usbip_event_add(&vdev->ud, VDEV_EVENT_ERROR_TCP);
                        return -1;
                }

                kfree(iso_buffer);
                usbip_dbg_vhci_tx("send txdata\n");

                total_size += txsize;
        }

        return total_size;
}

static struct vhci_unlink *dequeue_from_unlink_tx(struct vhci_device *vdev)
{
        struct vhci_unlink *unlink, *tmp;
        unsigned long flags;

        spin_lock_irqsave(&vdev->priv_lock, flags);

        list_for_each_entry_safe(unlink, tmp, &vdev->unlink_tx, list) {
                list_move_tail(&unlink->list, &vdev->unlink_rx);
                spin_unlock_irqrestore(&vdev->priv_lock, flags);
                return unlink;
        }

        spin_unlock_irqrestore(&vdev->priv_lock, flags);

        return NULL;
}

static int vhci_send_cmd_unlink(struct vhci_device *vdev)
{
        struct vhci_unlink *unlink = NULL;

        struct msghdr msg;
        struct kvec iov[3];
        size_t txsize;

        size_t total_size = 0;

        while ((unlink = dequeue_from_unlink_tx(vdev)) != NULL) {
                int ret;
                struct usbip_header pdu_header;

                txsize = 0;
                memset(&pdu_header, 0, sizeof(pdu_header));
                memset(&msg, 0, sizeof(msg));
                memset(&iov, 0, sizeof(iov));

                usbip_dbg_vhci_tx("setup cmd unlink, %lu\n", unlink->seqnum);

                /* 1. setup usbip_header */
                pdu_header.base.command = USBIP_CMD_UNLINK;
                pdu_header.base.seqnum  = unlink->seqnum;
                pdu_header.base.devid   = vdev->devid;
                pdu_header.base.ep      = 0;
                pdu_header.u.cmd_unlink.seqnum = unlink->unlink_seqnum;

                usbip_header_correct_endian(&pdu_header, 1);

                iov[0].iov_base = &pdu_header;
                iov[0].iov_len  = sizeof(pdu_header);
                txsize += sizeof(pdu_header);

                ret = kernel_sendmsg(vdev->ud.tcp_socket, &msg, iov, 1, txsize);
                if (ret != txsize) {
                        pr_err("sendmsg failed!, ret=%d for %zd\n", ret,
                               txsize);
                        usbip_event_add(&vdev->ud, VDEV_EVENT_ERROR_TCP);
                        return -1;
                }

                usbip_dbg_vhci_tx("send txdata\n");

                total_size += txsize;
        }

        return total_size;
}

int vhci_tx_loop(void *data)
{
        struct usbip_device *ud = data;
        struct vhci_device *vdev = container_of(ud, struct vhci_device, ud);

        while (!kthread_should_stop()) {
                if (vhci_send_cmd_submit(vdev) < 0)
                        break;

                if (vhci_send_cmd_unlink(vdev) < 0)
                        break;

                wait_event_interruptible(vdev->waitq_tx,
                                         (!list_empty(&vdev->priv_tx) ||
                                          !list_empty(&vdev->unlink_tx) ||
                                          kthread_should_stop()));

                usbip_dbg_vhci_tx("pending urbs ?, now wake up\n");
        }

        return 0;
}