summaryrefslogtreecommitdiffstats
path: root/drivers/media/usb/uvc/uvc_isight.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/media/usb/uvc/uvc_isight.c')
-rw-r--r--drivers/media/usb/uvc/uvc_isight.c140
1 files changed, 140 insertions, 0 deletions
diff --git a/drivers/media/usb/uvc/uvc_isight.c b/drivers/media/usb/uvc/uvc_isight.c
new file mode 100644
index 000000000..43cda5e76
--- /dev/null
+++ b/drivers/media/usb/uvc/uvc_isight.c
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * 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>
+ */
+
+#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);
+ }
+}