forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
135 lines
3.7 KiB
135 lines
3.7 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
|
/* |
|
* uvc_isight.c -- USB Video Class driver - iSight support |
|
* |
|
* Copyright (C) 2006-2007 |
|
* Ivan N. Zlatev <[email protected]> |
|
* Copyright (C) 2008-2009 |
|
* Laurent Pinchart <[email protected]> |
|
*/ |
|
|
|
#include <linux/usb.h> |
|
#include <linux/kernel.h> |
|
#include <linux/mm.h> |
|
|
|
#include "uvcvideo.h" |
|
|
|
/* Built-in iSight webcams implements most of UVC 1.0 except a |
|
* different packet format. Instead of sending a header at the |
|
* beginning of each isochronous transfer payload, the webcam sends a |
|
* single header per image (on its own in a packet), followed by |
|
* packets containing data only. |
|
* |
|
* Offset Size (bytes) Description |
|
* ------------------------------------------------------------------ |
|
* 0x00 1 Header length |
|
* 0x01 1 Flags (UVC-compliant) |
|
* 0x02 4 Always equal to '11223344' |
|
* 0x06 8 Always equal to 'deadbeefdeadface' |
|
* 0x0e 16 Unknown |
|
* |
|
* The header can be prefixed by an optional, unknown-purpose byte. |
|
*/ |
|
|
|
static int isight_decode(struct uvc_video_queue *queue, struct uvc_buffer *buf, |
|
const u8 *data, unsigned int len) |
|
{ |
|
static const u8 hdr[] = { |
|
0x11, 0x22, 0x33, 0x44, |
|
0xde, 0xad, 0xbe, 0xef, |
|
0xde, 0xad, 0xfa, 0xce |
|
}; |
|
|
|
struct uvc_streaming *stream = uvc_queue_to_stream(queue); |
|
unsigned int maxlen, nbytes; |
|
u8 *mem; |
|
int is_header = 0; |
|
|
|
if (buf == NULL) |
|
return 0; |
|
|
|
if ((len >= 14 && memcmp(&data[2], hdr, 12) == 0) || |
|
(len >= 15 && memcmp(&data[3], hdr, 12) == 0)) { |
|
uvc_dbg(stream->dev, FRAME, "iSight header found\n"); |
|
is_header = 1; |
|
} |
|
|
|
/* Synchronize to the input stream by waiting for a header packet. */ |
|
if (buf->state != UVC_BUF_STATE_ACTIVE) { |
|
if (!is_header) { |
|
uvc_dbg(stream->dev, FRAME, |
|
"Dropping packet (out of sync)\n"); |
|
return 0; |
|
} |
|
|
|
buf->state = UVC_BUF_STATE_ACTIVE; |
|
} |
|
|
|
/* Mark the buffer as done if we're at the beginning of a new frame. |
|
* |
|
* Empty buffers (bytesused == 0) don't trigger end of frame detection |
|
* as it doesn't make sense to return an empty buffer. |
|
*/ |
|
if (is_header && buf->bytesused != 0) { |
|
buf->state = UVC_BUF_STATE_DONE; |
|
return -EAGAIN; |
|
} |
|
|
|
/* Copy the video data to the buffer. Skip header packets, as they |
|
* contain no data. |
|
*/ |
|
if (!is_header) { |
|
maxlen = buf->length - buf->bytesused; |
|
mem = buf->mem + buf->bytesused; |
|
nbytes = min(len, maxlen); |
|
memcpy(mem, data, nbytes); |
|
buf->bytesused += nbytes; |
|
|
|
if (len > maxlen || buf->bytesused == buf->length) { |
|
uvc_dbg(stream->dev, FRAME, |
|
"Frame complete (overflow)\n"); |
|
buf->state = UVC_BUF_STATE_DONE; |
|
} |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
void uvc_video_decode_isight(struct uvc_urb *uvc_urb, struct uvc_buffer *buf, |
|
struct uvc_buffer *meta_buf) |
|
{ |
|
struct urb *urb = uvc_urb->urb; |
|
struct uvc_streaming *stream = uvc_urb->stream; |
|
int ret, i; |
|
|
|
for (i = 0; i < urb->number_of_packets; ++i) { |
|
if (urb->iso_frame_desc[i].status < 0) { |
|
uvc_dbg(stream->dev, FRAME, |
|
"USB isochronous frame lost (%d)\n", |
|
urb->iso_frame_desc[i].status); |
|
} |
|
|
|
/* Decode the payload packet. |
|
* uvc_video_decode is entered twice when a frame transition |
|
* has been detected because the end of frame can only be |
|
* reliably detected when the first packet of the new frame |
|
* is processed. The first pass detects the transition and |
|
* closes the previous frame's buffer, the second pass |
|
* processes the data of the first payload of the new frame. |
|
*/ |
|
do { |
|
ret = isight_decode(&stream->queue, buf, |
|
urb->transfer_buffer + |
|
urb->iso_frame_desc[i].offset, |
|
urb->iso_frame_desc[i].actual_length); |
|
|
|
if (buf == NULL) |
|
break; |
|
|
|
if (buf->state == UVC_BUF_STATE_DONE || |
|
buf->state == UVC_BUF_STATE_ERROR) |
|
buf = uvc_queue_next_buffer(&stream->queue, |
|
buf); |
|
} while (ret == -EAGAIN); |
|
} |
|
}
|
|
|