xref: /openbmc/qemu/hw/usb/combined-packet.c (revision 3ae8a100)
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/osdep.h"
23 #include "qemu-common.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, packets_head)->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 == 16348 && 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