Merge ath-next from git://git.kernel.org/pub/scm/linux/kernel/git/kvalo/ath.git
[linux-2.6-microblaze.git] / drivers / media / usb / uvc / uvc_isight.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
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>
7  *      Copyright (C) 2008-2009
8  *              Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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  * ------------------------------------------------------------------
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
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,
35                 const u8 *data, unsigned int len)
36 {
37         static const u8 hdr[] = {
38                 0x11, 0x22, 0x33, 0x44,
39                 0xde, 0xad, 0xbe, 0xef,
40                 0xde, 0xad, 0xfa, 0xce
41         };
42
43         struct uvc_streaming *stream = uvc_queue_to_stream(queue);
44         unsigned int maxlen, nbytes;
45         u8 *mem;
46         int is_header = 0;
47
48         if (buf == NULL)
49                 return 0;
50
51         if ((len >= 14 && memcmp(&data[2], hdr, 12) == 0) ||
52             (len >= 15 && memcmp(&data[3], hdr, 12) == 0)) {
53                 uvc_dbg(stream->dev, FRAME, "iSight header found\n");
54                 is_header = 1;
55         }
56
57         /* Synchronize to the input stream by waiting for a header packet. */
58         if (buf->state != UVC_BUF_STATE_ACTIVE) {
59                 if (!is_header) {
60                         uvc_dbg(stream->dev, FRAME,
61                                 "Dropping packet (out of sync)\n");
62                         return 0;
63                 }
64
65                 buf->state = UVC_BUF_STATE_ACTIVE;
66         }
67
68         /* Mark the buffer as done if we're at the beginning of a new frame.
69          *
70          * Empty buffers (bytesused == 0) don't trigger end of frame detection
71          * as it doesn't make sense to return an empty buffer.
72          */
73         if (is_header && buf->bytesused != 0) {
74                 buf->state = UVC_BUF_STATE_DONE;
75                 return -EAGAIN;
76         }
77
78         /* Copy the video data to the buffer. Skip header packets, as they
79          * contain no data.
80          */
81         if (!is_header) {
82                 maxlen = buf->length - buf->bytesused;
83                 mem = buf->mem + buf->bytesused;
84                 nbytes = min(len, maxlen);
85                 memcpy(mem, data, nbytes);
86                 buf->bytesused += nbytes;
87
88                 if (len > maxlen || buf->bytesused == buf->length) {
89                         uvc_dbg(stream->dev, FRAME,
90                                 "Frame complete (overflow)\n");
91                         buf->state = UVC_BUF_STATE_DONE;
92                 }
93         }
94
95         return 0;
96 }
97
98 void uvc_video_decode_isight(struct uvc_urb *uvc_urb, struct uvc_buffer *buf,
99                         struct uvc_buffer *meta_buf)
100 {
101         struct urb *urb = uvc_urb->urb;
102         struct uvc_streaming *stream = uvc_urb->stream;
103         int ret, i;
104
105         for (i = 0; i < urb->number_of_packets; ++i) {
106                 if (urb->iso_frame_desc[i].status < 0) {
107                         uvc_dbg(stream->dev, FRAME,
108                                 "USB isochronous frame lost (%d)\n",
109                                 urb->iso_frame_desc[i].status);
110                 }
111
112                 /* Decode the payload packet.
113                  * uvc_video_decode is entered twice when a frame transition
114                  * has been detected because the end of frame can only be
115                  * reliably detected when the first packet of the new frame
116                  * is processed. The first pass detects the transition and
117                  * closes the previous frame's buffer, the second pass
118                  * processes the data of the first payload of the new frame.
119                  */
120                 do {
121                         ret = isight_decode(&stream->queue, buf,
122                                         urb->transfer_buffer +
123                                         urb->iso_frame_desc[i].offset,
124                                         urb->iso_frame_desc[i].actual_length);
125
126                         if (buf == NULL)
127                                 break;
128
129                         if (buf->state == UVC_BUF_STATE_DONE ||
130                             buf->state == UVC_BUF_STATE_ERROR)
131                                 buf = uvc_queue_next_buffer(&stream->queue,
132                                                         buf);
133                 } while (ret == -EAGAIN);
134         }
135 }