hw/usb/combined-packet.c

   1 /*
   2  * QEMU USB packet combining code (for input pipelining)
   3  *
   4  * Copyright(c) 2012 Red Hat, Inc.
   5  *
   6  * Red Hat Authors:
   7  * Hans de Goede <hdegoede@redhat.com>
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2 of the License, or(at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  21  */
  22 #include "qemu-common.h"
  23 #include "hw/usb.h"
  24 #include "qemu/iov.h"
  25 #include "trace.h"
  26
  27 static void usb_combined_packet_add(USBCombinedPacket *combined, USBPacket *p)
  28 {
  29     qemu_iovec_concat(&combined->iov, &p->iov, 0, p->iov.size);
  30     QTAILQ_INSERT_TAIL(&combined->packets, p, combined_entry);
  31     p->combined = combined;
  32 }
  33
  34 /* Note will free combined when the last packet gets removed */
  35 static void usb_combined_packet_remove(USBCombinedPacket *combined,
  36                                        USBPacket *p)
  37 {
  38     assert(p->combined == combined);
  39     p->combined = NULL;
  40     QTAILQ_REMOVE(&combined->packets, p, combined_entry);
  41     if (QTAILQ_EMPTY(&combined->packets)) {
  42         qemu_iovec_destroy(&combined->iov);
  43         g_free(combined);
  44     }
  45 }
  46
  47 /* Also handles completion of non combined packets for pipelined input eps */
  48 void usb_combined_input_packet_complete(USBDevice *dev, USBPacket *p)
  49 {
  50     USBCombinedPacket *combined = p->combined;
  51     USBEndpoint *ep = p->ep;
  52     USBPacket *next;
  53     int status, actual_length;
  54     bool short_not_ok, done = false;
  55
  56     if (combined == NULL) {
  57         usb_packet_complete_one(dev, p);
  58         goto leave;
  59     }
  60
  61     assert(combined->first == p && p == QTAILQ_FIRST(&combined->packets));
  62
  63     status = combined->first->status;
  64     actual_length = combined->first->actual_length;
  65     short_not_ok = QTAILQ_LAST(&combined->packets, packets_head)->short_not_ok;
  66
  67     QTAILQ_FOREACH_SAFE(p, &combined->packets, combined_entry, next) {
  68         if (!done) {
  69             /* Distribute data over uncombined packets */
  70             if (actual_length >= p->iov.size) {
  71                 p->actual_length = p->iov.size;
  72             } else {
  73                 /* Send short or error packet to complete the transfer */
  74                 p->actual_length = actual_length;
  75                 done = true;
  76             }
  77             /* Report status on the last packet */
  78             if (done || next == NULL) {
  79                 p->status = status;
  80             } else {
  81                 p->status = USB_RET_SUCCESS;
  82             }
  83             p->short_not_ok = short_not_ok;
  84             /* Note will free combined when the last packet gets removed! */
  85             usb_combined_packet_remove(combined, p);
  86             usb_packet_complete_one(dev, p);
  87             actual_length -= p->actual_length;
  88         } else {
  89             /* Remove any leftover packets from the queue */
  90             p->status = USB_RET_REMOVE_FROM_QUEUE;
  91             /* Note will free combined on the last packet! */
  92             dev->port->ops->complete(dev->port, p);
  93         }
  94     }
  95     /* Do not use combined here, it has been freed! */
  96 leave:
  97     /* Check if there are packets in the queue waiting for our completion */
  98     usb_ep_combine_input_packets(ep);
  99 }
 100
 101 /* May only be called for combined packets! */
 102 void usb_combined_packet_cancel(USBDevice *dev, USBPacket *p)
 103 {
 104     USBCombinedPacket *combined = p->combined;
 105     assert(combined != NULL);
 106     USBPacket *first = p->combined->first;
 107
 108     /* Note will free combined on the last packet! */
 109     usb_combined_packet_remove(combined, p);
 110     if (p == first) {
 111         usb_device_cancel_packet(dev, p);
 112     }
 113 }
 114
 115 /*
 116  * Large input transfers can get split into multiple input packets, this
 117  * function recombines them, removing the short_not_ok checks which all but
 118  * the last packet of such splits transfers have, thereby allowing input
 119  * transfer pipelining (which we cannot do on short_not_ok transfers)
 120  */
 121 void usb_ep_combine_input_packets(USBEndpoint *ep)
 122 {
 123     USBPacket *p, *u, *next, *prev = NULL, *first = NULL;
 124     USBPort *port = ep->dev->port;
 125     int totalsize;
 126
 127     assert(ep->pipeline);
 128     assert(ep->pid == USB_TOKEN_IN);
 129
 130     QTAILQ_FOREACH_SAFE(p, &ep->queue, queue, next) {
 131         /* Empty the queue on a halt */
 132         if (ep->halted) {
 133             p->status = USB_RET_REMOVE_FROM_QUEUE;
 134             port->ops->complete(port, p);
 135             continue;
 136         }
 137
 138         /* Skip packets already submitted to the device */
 139         if (p->state == USB_PACKET_ASYNC) {
 140             prev = p;
 141             continue;
 142         }
 143         usb_packet_check_state(p, USB_PACKET_QUEUED);
 144
 145         /*
 146          * If the previous (combined) packet has the short_not_ok flag set
 147          * stop, as we must not submit packets to the device after a transfer
 148          * ending with short_not_ok packet.
 149          */
 150         if (prev && prev->short_not_ok) {
 151             break;
 152         }
 153
 154         if (first) {
 155             if (first->combined == NULL) {
 156                 USBCombinedPacket *combined = g_new0(USBCombinedPacket, 1);
 157
 158                 combined->first = first;
 159                 QTAILQ_INIT(&combined->packets);
 160                 qemu_iovec_init(&combined->iov, 2);
 161                 usb_combined_packet_add(combined, first);
 162             }
 163             usb_combined_packet_add(first->combined, p);
 164         } else {
 165             first = p;
 166         }
 167
 168         /* Is this packet the last one of a (combined) transfer? */
 169         totalsize = (p->combined) ? p->combined->iov.size : p->iov.size;
 170         if ((p->iov.size % ep->max_packet_size) != 0 || !p->short_not_ok ||
 171                 next == NULL ||
 172                 /* Work around for Linux usbfs bulk splitting + migration */
 173                 (totalsize == 16348 && p->int_req)) {
 174             usb_device_handle_data(ep->dev, first);
 175             assert(first->status == USB_RET_ASYNC);
 176             if (first->combined) {
 177                 QTAILQ_FOREACH(u, &first->combined->packets, combined_entry) {
 178                     usb_packet_set_state(u, USB_PACKET_ASYNC);
 179                 }
 180             } else {
 181                 usb_packet_set_state(first, USB_PACKET_ASYNC);
 182             }
 183             first = NULL;
 184             prev = p;
 185         }
 186     }
 187 }