qemu

combined-packet.c (6735B)

---

 /*
  * 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 2.1 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 Lesser General Public License
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 #include "qemu/osdep.h"
 #include "qemu/units.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)) {
         qemu_iovec_destroy(&combined->iov);
         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)->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 == (16 * KiB - 36) && p->int_req) ||
                 /* Next package may grow combined package over 1MiB */
                 totalsize > 1 * MiB - ep->max_packet_size) {
             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;
         }
     }
 }