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