diff options
author | Jonathan Herman <hermanjl@cs.unc.edu> | 2013-01-22 10:38:37 -0500 |
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committer | Jonathan Herman <hermanjl@cs.unc.edu> | 2013-01-22 10:38:37 -0500 |
commit | fcc9d2e5a6c89d22b8b773a64fb4ad21ac318446 (patch) | |
tree | a57612d1888735a2ec7972891b68c1ac5ec8faea /drivers/media/video/uvc/uvc_isight.c | |
parent | 8dea78da5cee153b8af9c07a2745f6c55057fe12 (diff) |
Diffstat (limited to 'drivers/media/video/uvc/uvc_isight.c')
-rw-r--r-- | drivers/media/video/uvc/uvc_isight.c | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/drivers/media/video/uvc/uvc_isight.c b/drivers/media/video/uvc/uvc_isight.c new file mode 100644 index 00000000000..74bbe8f18f3 --- /dev/null +++ b/drivers/media/video/uvc/uvc_isight.c | |||
@@ -0,0 +1,137 @@ | |||
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> | ||
6 | * Copyright (C) 2008-2009 | ||
7 | * Laurent Pinchart <laurent.pinchart@ideasonboard.com> | ||
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 | |||
102 | void uvc_video_decode_isight(struct urb *urb, struct uvc_streaming *stream, | ||
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 { | ||
123 | ret = isight_decode(&stream->queue, buf, | ||
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) | ||
133 | buf = uvc_queue_next_buffer(&stream->queue, | ||
134 | buf); | ||
135 | } while (ret == -EAGAIN); | ||
136 | } | ||
137 | } | ||