rcar3: mse: allow mpegts packet type detection on single frames

refs #322044

Current implementation assumes multiple MTS frames (3+) being available
in a V4L buffer to perform packet type detection by searching for SYNC
octets in 3 adjacent MTS frames.
If a user writes single MTS/M2TS frames into V4L, the check will fail
as there're not enough data in individual buffers.

This patch concatenates available V4L MTS buffers for packet type check
and reduces the threshold down to 2 SYNC octets.

Signed-off-by: Andreas Pape <[email protected]>
[yyankovskyi: Minor cleanups and improvements]
Signed-off-by: Yan Yankovskyi <[email protected]>
Signed-off-by: Masaru Nagai <[email protected]>

mse_adapter_v4l2.c

@@ -354,31 +354,47 @@ static struct v4l2_adapter_temp_buffer *temp_buffer_get_prepared(
 #define MPEG2TS_SYNC            (0x47)
 #define MPEG2TS_M2TS_OFFSET     (4)
 #define MPEG2TS_M2TS_SIZE       (MPEG2TS_M2TS_OFFSET + MPEG2TS_TS_SIZE)
-static bool is_mpeg2ts_ts(unsigned char *tsp)
+#define MPEG2TS_MIN_LEN_REQUIRED (MPEG2TS_M2TS_OFFSET + MPEG2TS_M2TS_SIZE * 2)
+
+/* Check at least 2 adjacent packets.
+ * Optionally 3 if enough data are available.
+ */
+#define MPEG2TS_MIN_PKT_CHECK 2
+#define MPEG2TS_MAX_PKT_CHECK 3
+
+static bool is_mpeg2ts_ts(unsigned char *tsp, size_t len)
 {
-	if (tsp[0] == MPEG2TS_SYNC &&
-	    tsp[MPEG2TS_TS_SIZE] == MPEG2TS_SYNC &&
-	    tsp[MPEG2TS_TS_SIZE * 2] == MPEG2TS_SYNC)
-		return true;
-	else
-		return false;
+	size_t offs = 0;
+	unsigned int succ = 0;
+
+	while ((offs < len) && (succ < MPEG2TS_MAX_PKT_CHECK)) {
+		if (tsp[offs] != MPEG2TS_SYNC)
+			return false;
+		succ++;
+		offs += MPEG2TS_TS_SIZE;
+	}
+	return (succ >= MPEG2TS_MIN_PKT_CHECK) ? true : false;
 }
 
-static bool is_mpeg2ts_m2ts(unsigned char *tsp)
+static bool is_mpeg2ts_m2ts(unsigned char *tsp, size_t len)
 {
-	if (tsp[MPEG2TS_M2TS_OFFSET] == MPEG2TS_SYNC &&
-	    tsp[MPEG2TS_M2TS_OFFSET + MPEG2TS_M2TS_SIZE] == MPEG2TS_SYNC &&
-	    tsp[MPEG2TS_M2TS_OFFSET + MPEG2TS_M2TS_SIZE * 2] == MPEG2TS_SYNC)
-		return true;
-	else
-		return false;
+	size_t offs = MPEG2TS_M2TS_OFFSET;
+	unsigned int succ = 0;
+
+	while ((offs < len) && (succ < MPEG2TS_MAX_PKT_CHECK)) {
+		if (tsp[offs] != MPEG2TS_SYNC)
+			return false;
+		succ++;
+		offs += MPEG2TS_M2TS_SIZE;
+	}
+	return (succ >= MPEG2TS_MIN_PKT_CHECK) ? true : false;
 }
 
-static int get_mpeg2ts_format(unsigned char *buf)
+static int get_mpeg2ts_format(unsigned char *buf, size_t size)
 {
-	if (is_mpeg2ts_ts(buf))
+	if (is_mpeg2ts_ts(buf, size))
 		return MSE_MPEG2TS_TYPE_TS;
-	else if (is_mpeg2ts_m2ts(buf))
+	else if (is_mpeg2ts_m2ts(buf, size))
 		return MSE_MPEG2TS_TYPE_M2TS;
 	else
 		return -1;
@@ -414,15 +430,15 @@ static bool jpeg_frame_is_valid(unsigned char *buf, size_t size)
 
 static int temp_buffer_check_type(struct v4l2_adapter_device *vadp_dev,
 				  unsigned char *buf,
-				  size_t size)
+				  size_t size, size_t size_fmtchk)
 {
 	int ret;
 	u8 mk;
 	size_t offset = 0;
 
 	switch (vadp_dev->format.pixelformat) {
 	case V4L2_PIX_FMT_MPEG:
-		ret = get_mpeg2ts_format(buf);
+		ret = get_mpeg2ts_format(buf, size_fmtchk);
 		vadp_dev->mpeg2ts_type = ret;
 		vadp_dev->use_temp_buffer = !tspacket_size_is_valid(ret, size);
 		break;
@@ -1326,7 +1342,7 @@ static void prepare_stream_buffer(struct vb2_queue *vq)
 	struct v4l2_adapter_device *vadp_dev = vb2_get_drv_priv(vq);
 	struct v4l2_adapter_buffer *vadp_buf;
 	void *buf;
-	long size;
+	size_t size;
 	int ret = 0;
 
 	mse_debug("START vq=%p, type=%s\n", vq, v4l2_type_stringfy(vq->type));
@@ -1346,7 +1362,31 @@ static void prepare_stream_buffer(struct vb2_queue *vq)
 
 		/* Check stream type */
 		if (vadp_dev->sequence == 0) {
-			ret = temp_buffer_check_type(vadp_dev, buf, size);
+			unsigned char *check_type = buf;
+			size_t len = size;
+			unsigned char concat_buf[MPEG2TS_MIN_LEN_REQUIRED];
+			/* If the buffer is too small - concatenate several buffers */
+			if (size < MPEG2TS_MIN_LEN_REQUIRED &&
+			    vadp_dev->format.pixelformat == V4L2_PIX_FMT_MPEG) {
+				struct v4l2_adapter_buffer *tmp, *buf_next;
+
+				len = 0;
+				check_type = concat_buf;
+				list_for_each_entry_safe(tmp, buf_next,
+							 &vadp_dev->buf_list, list) {
+					void *tmp_buf = vb2_plane_vaddr(&tmp->vb.vb2_buf, 0);
+					size_t tmp_len = vb2_get_plane_payload(&tmp->vb.vb2_buf, 0);
+					size_t cpy = MPEG2TS_MIN_LEN_REQUIRED - len;
+
+					if (tmp_len < cpy)
+						cpy = tmp_len;
+					memcpy(concat_buf + len, tmp_buf, cpy);
+					len += cpy;
+					if (len >= MPEG2TS_MIN_LEN_REQUIRED)
+						break;
+				}
+			}
+			ret = temp_buffer_check_type(vadp_dev, check_type, size, len);
 			if (ret < 0) {
 				vadp_buffer_done(vadp_dev, vadp_buf,
 						 VB2_BUF_STATE_ERROR);