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 2.1 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 Lesser General Public License
  20  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  21  */
  22 #include "qemu/osdep.h"
  23 #include "qemu/units.h"
  24 #include "hw/usb.h"
  25 #include "qemu/iov.h"
  26 #include "trace.h"
  27
  28 static void usb_combined_packet_add(USBCombinedPacket *combined, USBPacket *p)
  29 {
  30     qemu_iovec_concat(&combined->iov, &p->iov, 0, p->iov.size);
  31     QTAILQ_INSERT_TAIL(&combined->packets, p, combined_entry);
  32     p->combined = combined;
  33 }
  34
  35 /* Note will free combined when the last packet gets removed */
  36 static void usb_combined_packet_remove(USBCombinedPacket *combined,
  37                                        USBPacket *p)
  38 {
  39     assert(p->combined == combined);
  40     p->combined = NULL;
  41     QTAILQ_REMOVE(&combined->packets, p, combined_entry);
  42     if (QTAILQ_EMPTY(&combined->packets)) {
  43         qemu_iovec_destroy(&combined->iov);
  44         g_free(combined);
  45     }
  46 }
  47
  48 /* Also handles completion of non combined packets for pipelined input eps */
  49 void usb_combined_input_packet_complete(USBDevice *dev, USBPacket *p)
  50 {
  51     USBCombinedPacket *combined = p->combined;
  52     USBEndpoint *ep = p->ep;
  53     USBPacket *next;
  54     int status, actual_length;
  55     bool short_not_ok, done = false;
  56
  57     if (combined == NULL) {
  58         usb_packet_complete_one(dev, p);
  59         goto leave;
  60     }
  61
  62     assert(combined->first == p && p == QTAILQ_FIRST(&combined->packets));
  63
  64     status = combined->first->status;
  65     actual_length = combined->first->actual_length;
  66     short_not_ok = QTAILQ_LAST(&combined->packets)->short_not_ok;
  67
  68     QTAILQ_FOREACH_SAFE(p, &combined->packets, combined_entry, next) {
  69         if (!done) {
  70             /* Distribute data over uncombined packets */
  71             if (actual_length >= p->iov.size) {
  72                 p->actual_length = p->iov.size;
  73             } else {
  74                 /* Send short or error packet to complete the transfer */
  75                 p->actual_length = actual_length;
  76                 done = true;
  77             }
  78             /* Report status on the last packet */
  79             if (done || next == NULL) {
  80                 p->status = status;
  81             } else {
  82                 p->status = USB_RET_SUCCESS;
  83             }
  84             p->short_not_ok = short_not_ok;
  85             /* Note will free combined when the last packet gets removed! */
  86             usb_combined_packet_remove(combined, p);
  87             usb_packet_complete_one(dev, p);
  88             actual_length -= p->actual_length;
  89         } else {
  90             /* Remove any leftover packets from the queue */
  91             p->status = USB_RET_REMOVE_FROM_QUEUE;
  92             /* Note will free combined on the last packet! */
  93             dev->port->ops->complete(dev->port, p);
  94         }
  95     }
  96     /* Do not use combined here, it has been freed! */
  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     USBPacket *first = p->combined->first;
 108
 109     /* Note will free combined on the last packet! */
 110     usb_combined_packet_remove(combined, p);
 111     if (p == first) {
 112         usb_device_cancel_packet(dev, p);
 113     }
 114 }
 115
 116 /*
 117  * Large input transfers can get split into multiple input packets, this
 118  * function recombines them, removing the short_not_ok checks which all but
 119  * the last packet of such splits transfers have, thereby allowing input
 120  * transfer pipelining (which we cannot do on short_not_ok transfers)
 121  */
 122 void usb_ep_combine_input_packets(USBEndpoint *ep)
 123 {
 124     USBPacket *p, *u, *next, *prev = NULL, *first = NULL;
 125     USBPort *port = ep->dev->port;
 126     int totalsize;
 127
 128     assert(ep->pipeline);
 129     assert(ep->pid == USB_TOKEN_IN);
 130
 131     QTAILQ_FOREACH_SAFE(p, &ep->queue, queue, next) {
 132         /* Empty the queue on a halt */
 133         if (ep->halted) {
 134             p->status = USB_RET_REMOVE_FROM_QUEUE;
 135             port->ops->complete(port, p);
 136             continue;
 137         }
 138
 139         /* Skip packets already submitted to the device */
 140         if (p->state == USB_PACKET_ASYNC) {
 141             prev = p;
 142             continue;
 143         }
 144         usb_packet_check_state(p, USB_PACKET_QUEUED);
 145
 146         /*
 147          * If the previous (combined) packet has the short_not_ok flag set
 148          * stop, as we must not submit packets to the device after a transfer
 149          * ending with short_not_ok packet.
 150          */
 151         if (prev && prev->short_not_ok) {
 152             break;
 153         }
 154
 155         if (first) {
 156             if (first->combined == NULL) {
 157                 USBCombinedPacket *combined = g_new0(USBCombinedPacket, 1);
 158
 159                 combined->first = first;
 160                 QTAILQ_INIT(&combined->packets);
 161                 qemu_iovec_init(&combined->iov, 2);
 162                 usb_combined_packet_add(combined, first);
 163             }
 164             usb_combined_packet_add(first->combined, p);
 165         } else {
 166             first = p;
 167         }
 168
 169         /* Is this packet the last one of a (combined) transfer? */
 170         totalsize = (p->combined) ? p->combined->iov.size : p->iov.size;
 171         if ((p->iov.size % ep->max_packet_size) != 0 || !p->short_not_ok ||
 172                 next == NULL ||
 173                 /* Work around for Linux usbfs bulk splitting + migration */
 174                 (totalsize == (16 * KiB - 36) && p->int_req) ||
 175                 /* Next package may grow combined package over 1MiB */
 176                 totalsize > 1 * MiB - ep->max_packet_size) {
 177             usb_device_handle_data(ep->dev, first);
 178             assert(first->status == USB_RET_ASYNC);
 179             if (first->combined) {
 180                 QTAILQ_FOREACH(u, &first->combined->packets, combined_entry) {
 181                     usb_packet_set_state(u, USB_PACKET_ASYNC);
 182                 }
 183             } else {
 184                 usb_packet_set_state(first, USB_PACKET_ASYNC);
 185             }
 186             first = NULL;
 187             prev = p;
 188         }
 189     }
 190 }