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 "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 static void usb_combined_packet_remove(USBCombinedPacket *combined,
  35                                        USBPacket *p)
  36 {
  37     assert(p->combined == combined);
  38     p->combined = NULL;
  39     QTAILQ_REMOVE(&combined->packets, p, combined_entry);
  40 }
  41
  42 /* Also handles completion of non combined packets for pipelined input eps */
  43 void usb_combined_input_packet_complete(USBDevice *dev, USBPacket *p)
  44 {
  45     USBCombinedPacket *combined = p->combined;
  46     USBEndpoint *ep = p->ep;
  47     USBPacket *next;
  48     enum { completing, complete, leftover };
  49     int status, actual_length, state = completing;
  50     bool short_not_ok;
  51
  52     if (combined == NULL) {
  53         usb_packet_complete_one(dev, p);
  54         goto leave;
  55     }
  56
  57     assert(combined->first == p && p == QTAILQ_FIRST(&combined->packets));
  58
  59     status = combined->first->status;
  60     actual_length = combined->first->actual_length;
  61     short_not_ok = QTAILQ_LAST(&combined->packets, packets_head)->short_not_ok;
  62
  63     QTAILQ_FOREACH_SAFE(p, &combined->packets, combined_entry, next) {
  64         if (state == completing) {
  65             /* Distribute data over uncombined packets */
  66             if (actual_length >= p->iov.size) {
  67                 p->actual_length = p->iov.size;
  68             } else {
  69                 /* Send short or error packet to complete the transfer */
  70                 p->actual_length = actual_length;
  71                 state = complete;
  72             }
  73             /* Report status on the last packet */
  74             if (state == complete || next == NULL) {
  75                 p->status = status;
  76             } else {
  77                 p->status = USB_RET_SUCCESS;
  78             }
  79             p->short_not_ok = short_not_ok;
  80             usb_combined_packet_remove(combined, p);
  81             usb_packet_complete_one(dev, p);
  82             actual_length -= p->actual_length;
  83         } else {
  84             /* Remove any leftover packets from the queue */
  85             state = leftover;
  86             p->status = USB_RET_REMOVE_FROM_QUEUE;
  87             dev->port->ops->complete(dev->port, p);
  88         }
  89     }
  90     /*
  91      * If we had leftover packets the hcd driver will have cancelled them
  92      * and usb_combined_packet_cancel has already freed combined!
  93      */
  94     if (state != leftover) {
  95         g_free(combined);
  96     }
  97 leave:
  98     /* Check if there are packets in the queue waiting for our completion */
  99     usb_ep_combine_input_packets(ep);
 100 }
 101
 102 /* May only be called for combined packets! */
 103 void usb_combined_packet_cancel(USBDevice *dev, USBPacket *p)
 104 {
 105     USBCombinedPacket *combined = p->combined;
 106     assert(combined != NULL);
 107
 108     usb_combined_packet_remove(combined, p);
 109     if (p == combined->first) {
 110         usb_device_cancel_packet(dev, p);
 111     }
 112     if (QTAILQ_EMPTY(&combined->packets)) {
 113         g_free(combined);
 114     }
 115 }
 116
 117 /*
 118  * Large input transfers can get split into multiple input packets, this
 119  * function recombines them, removing the short_not_ok checks which all but
 120  * the last packet of such splits transfers have, thereby allowing input
 121  * transfer pipelining (which we cannot do on short_not_ok transfers)
 122  */
 123 void usb_ep_combine_input_packets(USBEndpoint *ep)
 124 {
 125     USBPacket *p, *u, *next, *prev = NULL, *first = NULL;
 126     USBPort *port = ep->dev->port;
 127     int totalsize;
 128
 129     assert(ep->pipeline);
 130     assert(ep->pid == USB_TOKEN_IN);
 131
 132     QTAILQ_FOREACH_SAFE(p, &ep->queue, queue, next) {
 133         /* Empty the queue on a halt */
 134         if (ep->halted) {
 135             p->status = USB_RET_REMOVE_FROM_QUEUE;
 136             port->ops->complete(port, p);
 137             continue;
 138         }
 139
 140         /* Skip packets already submitted to the device */
 141         if (p->state == USB_PACKET_ASYNC) {
 142             prev = p;
 143             continue;
 144         }
 145         usb_packet_check_state(p, USB_PACKET_QUEUED);
 146
 147         /*
 148          * If the previous (combined) packet has the short_not_ok flag set
 149          * stop, as we must not submit packets to the device after a transfer
 150          * ending with short_not_ok packet.
 151          */
 152         if (prev && prev->short_not_ok) {
 153             break;
 154         }
 155
 156         if (first) {
 157             if (first->combined == NULL) {
 158                 USBCombinedPacket *combined = g_new0(USBCombinedPacket, 1);
 159
 160                 combined->first = first;
 161                 QTAILQ_INIT(&combined->packets);
 162                 qemu_iovec_init(&combined->iov, 2);
 163                 usb_combined_packet_add(combined, first);
 164             }
 165             usb_combined_packet_add(first->combined, p);
 166         } else {
 167             first = p;
 168         }
 169
 170         /* Is this packet the last one of a (combined) transfer? */
 171         totalsize = (p->combined) ? p->combined->iov.size : p->iov.size;
 172         if ((p->iov.size % ep->max_packet_size) != 0 || !p->short_not_ok ||
 173                 next == NULL ||
 174                 /* Work around for Linux usbfs bulk splitting + migration */
 175                 (totalsize == 16348 && p->int_req)) {
 176             usb_device_handle_data(ep->dev, first);
 177             assert(first->status == USB_RET_ASYNC);
 178             if (first->combined) {
 179                 QTAILQ_FOREACH(u, &first->combined->packets, combined_entry) {
 180                     usb_packet_set_state(u, USB_PACKET_ASYNC);
 181                 }
 182             } else {
 183                 usb_packet_set_state(first, USB_PACKET_ASYNC);
 184             }
 185             first = NULL;
 186             prev = p;
 187         }
 188     }
 189 }