1 files changed, 87 insertions, 0 deletions
diff --git a/drivers/media/platform/coda/coda-mpeg2.c b/drivers/media/platform/coda/coda-mpeg2.c
new file mode 100644
index 000000000000..6f3f6721d286
--- /dev/null
+++ b/drivers/media/platform/coda/coda-mpeg2.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Coda multi-standard codec IP - MPEG-2 helper functions
+ *
+ * Copyright (C) 2019 Pengutronix, Philipp Zabel
+ */
+
+#include <linux/kernel.h>
+#include <linux/videodev2.h>
+#include "coda.h"
+
+int coda_mpeg2_profile(int profile_idc)
+{
+	switch (profile_idc) {
+	case 5:
+		return V4L2_MPEG_VIDEO_MPEG2_PROFILE_SIMPLE;
+	case 4:
+		return V4L2_MPEG_VIDEO_MPEG2_PROFILE_MAIN;
+	case 3:
+		return V4L2_MPEG_VIDEO_MPEG2_PROFILE_SNR_SCALABLE;
+	case 2:
+		return V4L2_MPEG_VIDEO_MPEG2_PROFILE_SPATIALLY_SCALABLE;
+	case 1:
+		return V4L2_MPEG_VIDEO_MPEG2_PROFILE_HIGH;
+	default:
+		return -EINVAL;
+	}
+}
+
+int coda_mpeg2_level(int level_idc)
+{
+	switch (level_idc) {
+	case 10:
+		return V4L2_MPEG_VIDEO_MPEG2_LEVEL_LOW;
+	case 8:
+		return V4L2_MPEG_VIDEO_MPEG2_LEVEL_MAIN;
+	case 6:
+		return V4L2_MPEG_VIDEO_MPEG2_LEVEL_HIGH_1440;
+	case 4:
+		return V4L2_MPEG_VIDEO_MPEG2_LEVEL_HIGH;
+	default:
+		return -EINVAL;
+	}
+}
+
+/*
+ * Check if the buffer starts with the MPEG-2 sequence header (with or without
+ * quantization matrix) and extension header, for example:
+ *
+ *   00 00 01 b3 2d 01 e0 34 08 8b a3 81
+ *               10 11 11 12 12 12 13 13 13 13 14 14 14 14 14 15
+ *               15 15 15 15 15 16 16 16 16 16 16 16 17 17 17 17
+ *               17 17 17 17 18 18 18 19 18 18 18 19 1a 1a 1a 1a
+ *               19 1b 1b 1b 1b 1b 1c 1c 1c 1c 1e 1e 1e 1f 1f 21
+ *   00 00 01 b5 14 8a 00 01 00 00
+ *
+ * or:
+ *
+ *   00 00 01 b3 08 00 40 15 ff ff e0 28
+ *   00 00 01 b5 14 8a 00 01 00 00
+ *
+ * Returns the detected header size in bytes or 0.
+ */
+u32 coda_mpeg2_parse_headers(struct coda_ctx *ctx, u8 *buf, u32 size)
+{
+	static const u8 sequence_header_start[4] = { 0x00, 0x00, 0x01, 0xb3 };
+	static const union {
+		u8 extension_start[4];
+		u8 start_code_prefix[3];
+	} u = { { 0x00, 0x00, 0x01, 0xb5 } };
+
+	if (size < 22 ||
+	    memcmp(buf, sequence_header_start, 4) != 0)
+		return 0;
+
+	if ((size == 22 ||
+	     (size >= 25 && memcmp(buf + 22, u.start_code_prefix, 3) == 0)) &&
+	    memcmp(buf + 12, u.extension_start, 4) == 0)
+		return 22;
+
+	if ((size == 86 ||
+	     (size > 89 && memcmp(buf + 86, u.start_code_prefix, 3) == 0)) &&
+	    memcmp(buf + 76, u.extension_start, 4) == 0)
+		return 86;
+
+	return 0;
+}