[media] usbtv: Fix deinterlacing

The image data is laid out a bit more weirdly and thus needs more work to
properly interlace. What we get from hardware is V4L2_FIELD_ALTERNATE, but
since userspace support for it is practically nonexistent, thus we make
V4L2_FIELD_INTERLACED from it so that it's more easily interpreted.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: stable@vger.kernel.org

1 files changed, 25 insertions, 11 deletions

diff --git a/drivers/media/usb/usbtv/usbtv.c b/drivers/media/usb/usbtv/usbtv.c
index 095231608d25..55a45d34df22 100644
--- a/drivers/media/usb/usbtv/usbtv.c
+++ b/drivers/media/usb/usbtv/usbtv.c
@@ -56,7 +56,7 @@
 #define USBTV_CHUNK_SIZE        256
 #define USBTV_CHUNK             240
 #define USBTV_CHUNKS            (USBTV_WIDTH * USBTV_HEIGHT \
-                                        / 2 / USBTV_CHUNK)
+                                        / 4 / USBTV_CHUNK)
 
 /* Chunk header. */
 #define USBTV_MAGIC_OK(chunk)   ((be32_to_cpu(chunk[0]) & 0xff000000) \
@@ -259,6 +259,26 @@ static int usbtv_setup_capture(struct usbtv *usbtv)
         return 0;
 }
 
+/* Copy data from chunk into a frame buffer, deinterlacing the data
+ * into every second line. Unfortunately, they don't align nicely into
+ * 720 pixel lines, as the chunk is 240 words long, which is 480 pixels.
+ * Therefore, we break down the chunk into two halves before copyting,
+ * so that we can interleave a line if needed. */
+static void usbtv_chunk_to_vbuf(u32 *frame, u32 *src, int chunk_no, int odd)
+{
+        int half;
+
+        for (half = 0; half < 2; half++) {
+                int part_no = chunk_no * 2 + half;
+                int line = part_no / 3;
+                int part_index = (line * 2 + !odd) * 3 + (part_no % 3);
+
+                u32 *dst = &frame[part_index * USBTV_CHUNK/2];
+                memcpy(dst, src, USBTV_CHUNK/2 * sizeof(*src));
+                src += USBTV_CHUNK/2;
+        }
+}
+
 /* Called for each 256-byte image chunk.
  * First word identifies the chunk, followed by 240 words of image
  * data and padding. */
@@ -275,11 +295,6 @@ static void usbtv_image_chunk(struct usbtv *usbtv, u32 *chunk)
         frame_id = USBTV_FRAME_ID(chunk);
         odd = USBTV_ODD(chunk);
         chunk_no = USBTV_CHUNK_NO(chunk);
-
-        /* Deinterlace. TODO: Use interlaced frame format. */
-        chunk_no = (chunk_no - chunk_no % 3) * 2 + chunk_no % 3;
-        chunk_no += !odd * 3;
-
         if (chunk_no >= USBTV_CHUNKS)
                 return;
 
@@ -298,12 +313,11 @@ static void usbtv_image_chunk(struct usbtv *usbtv, u32 *chunk)
         buf = list_first_entry(&usbtv->bufs, struct usbtv_buf, list);
         frame = vb2_plane_vaddr(&buf->vb, 0);
 
-        /* Copy the chunk. */
-        memcpy(&frame[chunk_no * USBTV_CHUNK], &chunk[1],
-                        USBTV_CHUNK * sizeof(chunk[1]));
+        /* Copy the chunk data. */
+        usbtv_chunk_to_vbuf(frame, &chunk[1], chunk_no, odd);
 
         /* Last chunk in a frame, signalling an end */
-        if (usbtv->frame_id && chunk_no == USBTV_CHUNKS-1) {
+        if (odd && chunk_no == USBTV_CHUNKS-1) {
                 int size = vb2_plane_size(&buf->vb, 0);
 
                 buf->vb.v4l2_buf.field = V4L2_FIELD_INTERLACED;
@@ -582,7 +596,7 @@ static int usbtv_queue_setup(struct vb2_queue *vq,
         if (*nbuffers < 2)
                 *nbuffers = 2;
         *nplanes = 1;
-        sizes[0] = USBTV_CHUNK * USBTV_CHUNKS * sizeof(u32);
+        sizes[0] = USBTV_WIDTH * USBTV_HEIGHT / 2 * sizeof(u32);
 
         return 0;
 }