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/*

 * QEMU USB packet combining code (for input pipelining)

 *

 * Copyright(c) 2012 Red Hat, Inc.

 *

 * Red Hat Authors:

 * Hans de Goede <hdegoede@redhat.com>

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or(at your option) any later version.

 *

 * This library 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, see <http://www.gnu.org/licenses/>.

 */

#include "qemu-common.h"

#include "hw/usb.h"

#include "qemu/iov.h"

#include "trace.h"

static void usb_combined_packet_add(USBCombinedPacket *combined, USBPacket *p)

{

    qemu_iovec_concat(&combined->iov, &p->iov, 0, p->iov.size);

    QTAILQ_INSERT_TAIL(&combined->packets, p, combined_entry);

    p->combined = combined;

}

/* Note will free combined when the last packet gets removed */

static void usb_combined_packet_remove(USBCombinedPacket *combined,

                                       USBPacket *p)

{

    assert(p->combined == combined);

    p->combined = NULL;

    QTAILQ_REMOVE(&combined->packets, p, combined_entry);

    if (QTAILQ_EMPTY(&combined->packets)) {

        g_free(combined);

    }

}

/* Also handles completion of non combined packets for pipelined input eps */

void usb_combined_input_packet_complete(USBDevice *dev, USBPacket *p)

{

    USBCombinedPacket *combined = p->combined;

    USBEndpoint *ep = p->ep;

    USBPacket *next;

    int status, actual_length;

    bool short_not_ok, done = false;

    if (combined == NULL) {

        usb_packet_complete_one(dev, p);

        goto leave;

    }

    assert(combined->first == p && p == QTAILQ_FIRST(&combined->packets));

    status = combined->first->status;

    actual_length = combined->first->actual_length;

    short_not_ok = QTAILQ_LAST(&combined->packets, packets_head)->short_not_ok;

    QTAILQ_FOREACH_SAFE(p, &combined->packets, combined_entry, next) {

        if (!done) {

            /* Distribute data over uncombined packets */

            if (actual_length >= p->iov.size) {

                p->actual_length = p->iov.size;

            } else {

                /* Send short or error packet to complete the transfer */

                p->actual_length = actual_length;

                done = true;

            }

            /* Report status on the last packet */

            if (done || next == NULL) {

                p->status = status;

            } else {

                p->status = USB_RET_SUCCESS;

            }

            p->short_not_ok = short_not_ok;

            /* Note will free combined when the last packet gets removed! */

            usb_combined_packet_remove(combined, p);

            usb_packet_complete_one(dev, p);

            actual_length -= p->actual_length;

        } else {

            /* Remove any leftover packets from the queue */

            p->status = USB_RET_REMOVE_FROM_QUEUE;

            /* Note will free combined on the last packet! */

            dev->port->ops->complete(dev->port, p);

        }

    }

    /* Do not use combined here, it has been freed! */

leave:

    /* Check if there are packets in the queue waiting for our completion */

    usb_ep_combine_input_packets(ep);

}

/* May only be called for combined packets! */

void usb_combined_packet_cancel(USBDevice *dev, USBPacket *p)

{

    USBCombinedPacket *combined = p->combined;

    assert(combined != NULL);

    USBPacket *first = p->combined->first;

    /* Note will free combined on the last packet! */

    usb_combined_packet_remove(combined, p);

    if (p == first) {

        usb_device_cancel_packet(dev, p);

    }

}

/*

 * Large input transfers can get split into multiple input packets, this

 * function recombines them, removing the short_not_ok checks which all but

 * the last packet of such splits transfers have, thereby allowing input

 * transfer pipelining (which we cannot do on short_not_ok transfers)

 */

void usb_ep_combine_input_packets(USBEndpoint *ep)

{

    USBPacket *p, *u, *next, *prev = NULL, *first = NULL;

    USBPort *port = ep->dev->port;

    int totalsize;

    assert(ep->pipeline);

    assert(ep->pid == USB_TOKEN_IN);

    QTAILQ_FOREACH_SAFE(p, &ep->queue, queue, next) {

        /* Empty the queue on a halt */

        if (ep->halted) {

            p->status = USB_RET_REMOVE_FROM_QUEUE;

            port->ops->complete(port, p);

            continue;

        }

        /* Skip packets already submitted to the device */

        if (p->state == USB_PACKET_ASYNC) {

            prev = p;

            continue;

        }

        usb_packet_check_state(p, USB_PACKET_QUEUED);

        /*

         * If the previous (combined) packet has the short_not_ok flag set

         * stop, as we must not submit packets to the device after a transfer

         * ending with short_not_ok packet.

         */

        if (prev && prev->short_not_ok) {

            break;

        }

        if (first) {

            if (first->combined == NULL) {

                USBCombinedPacket *combined = g_new0(USBCombinedPacket, 1);

                combined->first = first;

                QTAILQ_INIT(&combined->packets);

                qemu_iovec_init(&combined->iov, 2);

                usb_combined_packet_add(combined, first);

            }

            usb_combined_packet_add(first->combined, p);

        } else {

            first = p;

        }

        /* Is this packet the last one of a (combined) transfer? */

        totalsize = (p->combined) ? p->combined->iov.size : p->iov.size;

        if ((p->iov.size % ep->max_packet_size) != 0 || !p->short_not_ok ||

                next == NULL ||

                /* Work around for Linux usbfs bulk splitting + migration */

                (totalsize == 16348 && p->int_req)) {

            usb_device_handle_data(ep->dev, first);

            assert(first->status == USB_RET_ASYNC);

            if (first->combined) {

                QTAILQ_FOREACH(u, &first->combined->packets, combined_entry) {

                    usb_packet_set_state(u, USB_PACKET_ASYNC);

                }

            } else {

                usb_packet_set_state(first, USB_PACKET_ASYNC);

            }

            first = NULL;

            prev = p;

        }

    }

}