X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=kernel%2Fdrivers%2Fmedia%2Fusb%2Fuvc%2Fuvc_isight.c;fp=kernel%2Fdrivers%2Fmedia%2Fusb%2Fuvc%2Fuvc_isight.c;h=8510e7259e7639cdf30e343801fa38792dd619f0;hb=9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00;hp=0000000000000000000000000000000000000000;hpb=98260f3884f4a202f9ca5eabed40b1354c489b29;p=kvmfornfv.git

diff --git a/kernel/drivers/media/usb/uvc/uvc_isight.c b/kernel/drivers/media/usb/uvc/uvc_isight.c
new file mode 100644
index 000000000..8510e7259
--- /dev/null
+++ b/kernel/drivers/media/usb/uvc/uvc_isight.c
@@ -0,0 +1,137 @@
+/*
+ *      uvc_isight.c  --  USB Video Class driver - iSight support
+ *
+ *	Copyright (C) 2006-2007
+ *		Ivan N. Zlatev <contact@i-nz.net>
+ *	Copyright (C) 2008-2009
+ *		Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+ *
+ *      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 <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
+	};
+
+	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->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_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_streaming *stream,
+		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(&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);
+	}
+}