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
28static 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 */
36static 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 */
49void 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! */
97leave:
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! */
103void 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 */
122void 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 usb_device_handle_data(ep->dev, first);
176 assert(first->status == USB_RET_ASYNC);
177 if (first->combined) {
178 QTAILQ_FOREACH(u, &first->combined->packets, combined_entry) {
179 usb_packet_set_state(u, USB_PACKET_ASYNC);
180 }
181 } else {
182 usb_packet_set_state(first, USB_PACKET_ASYNC);
183 }
184 first = NULL;
185 prev = p;
186 }
187 }
188}
189