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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
c0efd232 LP |
2 | /* |
3 | * uvc_isight.c -- USB Video Class driver - iSight support | |
4 | * | |
5 | * Copyright (C) 2006-2007 | |
6 | * Ivan N. Zlatev <contact@i-nz.net> | |
2c2d264b | 7 | * Copyright (C) 2008-2009 |
11fc5baf | 8 | * Laurent Pinchart <laurent.pinchart@ideasonboard.com> |
c0efd232 LP |
9 | */ |
10 | ||
11 | #include <linux/usb.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/mm.h> | |
14 | ||
15 | #include "uvcvideo.h" | |
16 | ||
17 | /* Built-in iSight webcams implements most of UVC 1.0 except a | |
18 | * different packet format. Instead of sending a header at the | |
19 | * beginning of each isochronous transfer payload, the webcam sends a | |
20 | * single header per image (on its own in a packet), followed by | |
21 | * packets containing data only. | |
22 | * | |
23 | * Offset Size (bytes) Description | |
24 | * ------------------------------------------------------------------ | |
6e6a8b5a MCC |
25 | * 0x00 1 Header length |
26 | * 0x01 1 Flags (UVC-compliant) | |
27 | * 0x02 4 Always equal to '11223344' | |
28 | * 0x06 8 Always equal to 'deadbeefdeadface' | |
29 | * 0x0e 16 Unknown | |
c0efd232 LP |
30 | * |
31 | * The header can be prefixed by an optional, unknown-purpose byte. | |
32 | */ | |
33 | ||
34 | static int isight_decode(struct uvc_video_queue *queue, struct uvc_buffer *buf, | |
2c6b222c | 35 | const u8 *data, unsigned int len) |
c0efd232 | 36 | { |
2c6b222c | 37 | static const u8 hdr[] = { |
c0efd232 LP |
38 | 0x11, 0x22, 0x33, 0x44, |
39 | 0xde, 0xad, 0xbe, 0xef, | |
40 | 0xde, 0xad, 0xfa, 0xce | |
41 | }; | |
42 | ||
43 | unsigned int maxlen, nbytes; | |
2c6b222c | 44 | u8 *mem; |
c0efd232 LP |
45 | int is_header = 0; |
46 | ||
47 | if (buf == NULL) | |
48 | return 0; | |
49 | ||
50 | if ((len >= 14 && memcmp(&data[2], hdr, 12) == 0) || | |
51 | (len >= 15 && memcmp(&data[3], hdr, 12) == 0)) { | |
52 | uvc_trace(UVC_TRACE_FRAME, "iSight header found\n"); | |
53 | is_header = 1; | |
54 | } | |
55 | ||
56 | /* Synchronize to the input stream by waiting for a header packet. */ | |
57 | if (buf->state != UVC_BUF_STATE_ACTIVE) { | |
58 | if (!is_header) { | |
59 | uvc_trace(UVC_TRACE_FRAME, "Dropping packet (out of " | |
60 | "sync).\n"); | |
61 | return 0; | |
62 | } | |
63 | ||
64 | buf->state = UVC_BUF_STATE_ACTIVE; | |
65 | } | |
66 | ||
67 | /* Mark the buffer as done if we're at the beginning of a new frame. | |
68 | * | |
69 | * Empty buffers (bytesused == 0) don't trigger end of frame detection | |
70 | * as it doesn't make sense to return an empty buffer. | |
71 | */ | |
3d95e932 | 72 | if (is_header && buf->bytesused != 0) { |
c0efd232 LP |
73 | buf->state = UVC_BUF_STATE_DONE; |
74 | return -EAGAIN; | |
75 | } | |
76 | ||
77 | /* Copy the video data to the buffer. Skip header packets, as they | |
78 | * contain no data. | |
79 | */ | |
80 | if (!is_header) { | |
3d95e932 LP |
81 | maxlen = buf->length - buf->bytesused; |
82 | mem = buf->mem + buf->bytesused; | |
c0efd232 LP |
83 | nbytes = min(len, maxlen); |
84 | memcpy(mem, data, nbytes); | |
3d95e932 | 85 | buf->bytesused += nbytes; |
c0efd232 | 86 | |
3d95e932 | 87 | if (len > maxlen || buf->bytesused == buf->length) { |
c0efd232 LP |
88 | uvc_trace(UVC_TRACE_FRAME, "Frame complete " |
89 | "(overflow).\n"); | |
90 | buf->state = UVC_BUF_STATE_DONE; | |
91 | } | |
92 | } | |
93 | ||
94 | return 0; | |
95 | } | |
96 | ||
c6d664fe KB |
97 | void uvc_video_decode_isight(struct uvc_urb *uvc_urb, struct uvc_buffer *buf, |
98 | struct uvc_buffer *meta_buf) | |
c0efd232 | 99 | { |
c6d664fe KB |
100 | struct urb *urb = uvc_urb->urb; |
101 | struct uvc_streaming *stream = uvc_urb->stream; | |
c0efd232 LP |
102 | int ret, i; |
103 | ||
104 | for (i = 0; i < urb->number_of_packets; ++i) { | |
105 | if (urb->iso_frame_desc[i].status < 0) { | |
106 | uvc_trace(UVC_TRACE_FRAME, "USB isochronous frame " | |
107 | "lost (%d).\n", | |
108 | urb->iso_frame_desc[i].status); | |
109 | } | |
110 | ||
111 | /* Decode the payload packet. | |
112 | * uvc_video_decode is entered twice when a frame transition | |
113 | * has been detected because the end of frame can only be | |
114 | * reliably detected when the first packet of the new frame | |
115 | * is processed. The first pass detects the transition and | |
116 | * closes the previous frame's buffer, the second pass | |
117 | * processes the data of the first payload of the new frame. | |
118 | */ | |
119 | do { | |
35f02a68 | 120 | ret = isight_decode(&stream->queue, buf, |
c0efd232 LP |
121 | urb->transfer_buffer + |
122 | urb->iso_frame_desc[i].offset, | |
123 | urb->iso_frame_desc[i].actual_length); | |
124 | ||
125 | if (buf == NULL) | |
126 | break; | |
127 | ||
128 | if (buf->state == UVC_BUF_STATE_DONE || | |
129 | buf->state == UVC_BUF_STATE_ERROR) | |
35f02a68 LP |
130 | buf = uvc_queue_next_buffer(&stream->queue, |
131 | buf); | |
c0efd232 LP |
132 | } while (ret == -EAGAIN); |
133 | } | |
134 | } |