Commit | Line | Data |
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c0efd232 LP |
1 | /* |
2 | * uvc_isight.c -- USB Video Class driver - iSight support | |
3 | * | |
4 | * Copyright (C) 2006-2007 | |
5 | * Ivan N. Zlatev <contact@i-nz.net> | |
2c2d264b | 6 | * Copyright (C) 2008-2009 |
11fc5baf | 7 | * Laurent Pinchart <laurent.pinchart@ideasonboard.com> |
c0efd232 LP |
8 | * |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License as published by | |
11 | * the Free Software Foundation; either version 2 of the License, or | |
12 | * (at your option) any later version. | |
13 | * | |
14 | */ | |
15 | ||
16 | #include <linux/usb.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/mm.h> | |
19 | ||
20 | #include "uvcvideo.h" | |
21 | ||
22 | /* Built-in iSight webcams implements most of UVC 1.0 except a | |
23 | * different packet format. Instead of sending a header at the | |
24 | * beginning of each isochronous transfer payload, the webcam sends a | |
25 | * single header per image (on its own in a packet), followed by | |
26 | * packets containing data only. | |
27 | * | |
28 | * Offset Size (bytes) Description | |
29 | * ------------------------------------------------------------------ | |
30 | * 0x00 1 Header length | |
31 | * 0x01 1 Flags (UVC-compliant) | |
32 | * 0x02 4 Always equal to '11223344' | |
33 | * 0x06 8 Always equal to 'deadbeefdeadface' | |
34 | * 0x0e 16 Unknown | |
35 | * | |
36 | * The header can be prefixed by an optional, unknown-purpose byte. | |
37 | */ | |
38 | ||
39 | static int isight_decode(struct uvc_video_queue *queue, struct uvc_buffer *buf, | |
40 | const __u8 *data, unsigned int len) | |
41 | { | |
42 | static const __u8 hdr[] = { | |
43 | 0x11, 0x22, 0x33, 0x44, | |
44 | 0xde, 0xad, 0xbe, 0xef, | |
45 | 0xde, 0xad, 0xfa, 0xce | |
46 | }; | |
47 | ||
48 | unsigned int maxlen, nbytes; | |
49 | __u8 *mem; | |
50 | int is_header = 0; | |
51 | ||
52 | if (buf == NULL) | |
53 | return 0; | |
54 | ||
55 | if ((len >= 14 && memcmp(&data[2], hdr, 12) == 0) || | |
56 | (len >= 15 && memcmp(&data[3], hdr, 12) == 0)) { | |
57 | uvc_trace(UVC_TRACE_FRAME, "iSight header found\n"); | |
58 | is_header = 1; | |
59 | } | |
60 | ||
61 | /* Synchronize to the input stream by waiting for a header packet. */ | |
62 | if (buf->state != UVC_BUF_STATE_ACTIVE) { | |
63 | if (!is_header) { | |
64 | uvc_trace(UVC_TRACE_FRAME, "Dropping packet (out of " | |
65 | "sync).\n"); | |
66 | return 0; | |
67 | } | |
68 | ||
69 | buf->state = UVC_BUF_STATE_ACTIVE; | |
70 | } | |
71 | ||
72 | /* Mark the buffer as done if we're at the beginning of a new frame. | |
73 | * | |
74 | * Empty buffers (bytesused == 0) don't trigger end of frame detection | |
75 | * as it doesn't make sense to return an empty buffer. | |
76 | */ | |
77 | if (is_header && buf->buf.bytesused != 0) { | |
78 | buf->state = UVC_BUF_STATE_DONE; | |
79 | return -EAGAIN; | |
80 | } | |
81 | ||
82 | /* Copy the video data to the buffer. Skip header packets, as they | |
83 | * contain no data. | |
84 | */ | |
85 | if (!is_header) { | |
86 | maxlen = buf->buf.length - buf->buf.bytesused; | |
87 | mem = queue->mem + buf->buf.m.offset + buf->buf.bytesused; | |
88 | nbytes = min(len, maxlen); | |
89 | memcpy(mem, data, nbytes); | |
90 | buf->buf.bytesused += nbytes; | |
91 | ||
92 | if (len > maxlen || buf->buf.bytesused == buf->buf.length) { | |
93 | uvc_trace(UVC_TRACE_FRAME, "Frame complete " | |
94 | "(overflow).\n"); | |
95 | buf->state = UVC_BUF_STATE_DONE; | |
96 | } | |
97 | } | |
98 | ||
99 | return 0; | |
100 | } | |
101 | ||
35f02a68 | 102 | void uvc_video_decode_isight(struct urb *urb, struct uvc_streaming *stream, |
c0efd232 LP |
103 | struct uvc_buffer *buf) |
104 | { | |
105 | int ret, i; | |
106 | ||
107 | for (i = 0; i < urb->number_of_packets; ++i) { | |
108 | if (urb->iso_frame_desc[i].status < 0) { | |
109 | uvc_trace(UVC_TRACE_FRAME, "USB isochronous frame " | |
110 | "lost (%d).\n", | |
111 | urb->iso_frame_desc[i].status); | |
112 | } | |
113 | ||
114 | /* Decode the payload packet. | |
115 | * uvc_video_decode is entered twice when a frame transition | |
116 | * has been detected because the end of frame can only be | |
117 | * reliably detected when the first packet of the new frame | |
118 | * is processed. The first pass detects the transition and | |
119 | * closes the previous frame's buffer, the second pass | |
120 | * processes the data of the first payload of the new frame. | |
121 | */ | |
122 | do { | |
35f02a68 | 123 | ret = isight_decode(&stream->queue, buf, |
c0efd232 LP |
124 | urb->transfer_buffer + |
125 | urb->iso_frame_desc[i].offset, | |
126 | urb->iso_frame_desc[i].actual_length); | |
127 | ||
128 | if (buf == NULL) | |
129 | break; | |
130 | ||
131 | if (buf->state == UVC_BUF_STATE_DONE || | |
132 | buf->state == UVC_BUF_STATE_ERROR) | |
35f02a68 LP |
133 | buf = uvc_queue_next_buffer(&stream->queue, |
134 | buf); | |
c0efd232 LP |
135 | } while (ret == -EAGAIN); |
136 | } | |
137 | } |