1 files changed, 134 insertions, 0 deletions

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 <contact@i-nz.net>
+ *
+ *      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->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);
+        }
+}