From c0efd232929c2cd87238de2cccdaf4e845be5b0c Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Mon, 30 Jun 2008 15:04:50 -0300 Subject: V4L/DVB (8145a): USB Video Class driver This driver supports video input devices compliant with the USB Video Class specification. This means lots of currently manufactured webcams, and probably most of the future ones. Signed-off-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/uvc/uvc_isight.c | 134 +++++++++++++++++++++++++++++++++++ 1 file changed, 134 insertions(+) create mode 100644 drivers/media/video/uvc/uvc_isight.c (limited to 'drivers/media/video/uvc/uvc_isight.c') diff --git a/drivers/media/video/uvc/uvc_isight.c b/drivers/media/video/uvc/uvc_isight.c new file mode 100644 index 000000000000..37bdefdbead5 --- /dev/null +++ b/drivers/media/video/uvc/uvc_isight.c @@ -0,0 +1,134 @@ +/* + * uvc_isight.c -- USB Video Class driver - iSight support + * + * Copyright (C) 2006-2007 + * Ivan N. Zlatev + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + */ + +#include +#include +#include + +#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 + }; + + 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_trace(UVC_TRACE_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_trace(UVC_TRACE_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->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->buf.length - buf->buf.bytesused; + mem = queue->mem + buf->buf.m.offset + buf->buf.bytesused; + nbytes = min(len, maxlen); + memcpy(mem, data, nbytes); + buf->buf.bytesused += nbytes; + + if (len > maxlen || buf->buf.bytesused == buf->buf.length) { + uvc_trace(UVC_TRACE_FRAME, "Frame complete " + "(overflow).\n"); + buf->state = UVC_BUF_STATE_DONE; + } + } + + return 0; +} + +void uvc_video_decode_isight(struct urb *urb, struct uvc_video_device *video, + struct uvc_buffer *buf) +{ + int ret, i; + + for (i = 0; i < urb->number_of_packets; ++i) { + if (urb->iso_frame_desc[i].status < 0) { + uvc_trace(UVC_TRACE_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(&video->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(&video->queue, buf); + } while (ret == -EAGAIN); + } +} -- cgit v1.2.3