media: Add parsing for APP14 data segment in jpeg helpers

According to Rec. ITU-T T.872 (06/2012) 6.5.3
APP14 segment is for color encoding, it contains a transform flag, which
may have values of 0, 1 and 2 and are interpreted as follows:
0 - CMYK for images that are encoded with four components
  - RGB for images that are encoded with three components
1 - An image encoded with three components using YCbCr colour encoding.
2 - An image encoded with four components using YCCK colour encoding.

This is used in imx-jpeg decoder, to distinguish between
YUV444 and RGB24.

Signed-off-by: Mirela Rabulea <mirela.rabulea@nxp.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

1 files changed, 41 insertions, 1 deletions

diff --git a/drivers/media/v4l2-core/v4l2-jpeg.c b/drivers/media/v4l2-core/v4l2-jpeg.c
index 9071b6cc6d0e..ede40f2a5456 100644
--- a/drivers/media/v4l2-core/v4l2-jpeg.c
+++ b/drivers/media/v4l2-core/v4l2-jpeg.c
@@ -45,6 +45,7 @@ MODULE_LICENSE("GPL");
 #define DHP	0xffde	/* hierarchical progression */
 #define EXP	0xffdf	/* expand reference */
 #define APP0	0xffe0	/* application data */
+#define APP14	0xffee	/* application data for colour encoding */
 #define APP15	0xffef
 #define JPG0	0xfff0	/* extensions */
 #define JPG13	0xfffd
@@ -444,6 +445,39 @@ static int jpeg_skip_segment(struct jpeg_stream *stream)
 	return jpeg_skip(stream, len - 2);
 }
 
+/* Rec. ITU-T T.872 (06/2012) 6.5.3 */
+static int jpeg_parse_app14_data(struct jpeg_stream *stream,
+				 enum v4l2_jpeg_app14_tf *tf)
+{
+	int ret;
+	int lp;
+	int skip;
+
+	lp = jpeg_get_word_be(stream);
+	if (lp < 0)
+		return lp;
+
+	/* Check for "Adobe\0" in Ap1..6 */
+	if (stream->curr + 6 > stream->end ||
+	    strncmp(stream->curr, "Adobe\0", 6))
+		return -EINVAL;
+
+	/* get to Ap12 */
+	ret = jpeg_skip(stream, 11);
+	if (ret < 0)
+		return ret;
+
+	ret = jpeg_get_byte(stream);
+	if (ret < 0)
+		return ret;
+
+	*tf = ret;
+
+	/* skip the rest of the segment, this ensures at least it is complete */
+	skip = lp - 2 - 11;
+	return jpeg_skip(stream, skip);
+}
+
 /**
  * v4l2_jpeg_parse_header - locate marker segments and optionally parse headers
  * @buf: address of the JPEG buffer, should start with a SOI marker
@@ -476,6 +510,9 @@ int v4l2_jpeg_parse_header(void *buf, size_t len, struct v4l2_jpeg_header *out)
 	if (marker != SOI)
 		return -EINVAL;
 
+	/* init value to signal if this marker is not present */
+	out->app14_tf = V4L2_JPEG_APP14_TF_UNKNOWN;
+
 	/* loop through marker segments */
 	while ((marker = jpeg_next_marker(&stream)) >= 0) {
 		switch (marker) {
@@ -519,7 +556,10 @@ int v4l2_jpeg_parse_header(void *buf, size_t len, struct v4l2_jpeg_header *out)
 			ret = jpeg_parse_restart_interval(&stream,
 							&out->restart_interval);
 			break;
-
+		case APP14:
+			ret = jpeg_parse_app14_data(&stream,
+						    &out->app14_tf);
+			break;
 		case SOS:
 			ret = jpeg_reference_segment(&stream, &out->sos);
 			if (ret < 0)