From: Mirela Rabulea <mirela.rabulea@nxp.com>

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>
---
Changes in v7:
  Check there are 6 bytes available in the stream before checking for "Adobe\0"
  Change jpeg_parse_app14_data function to differentiate between the 3 scenarios: app14 missing, or app14 present but with/without parsing errors:
    App14 missing => Added V4L2_JPEG_APP14_TF_UNKNOWN to the enum v4l2_jpeg_app14_tf, use it to indicate app14 & TF is missing
	App14 present without parsing errors => Return the transform flag value as enum v4l2_jpeg_app14_tf (new paramater of jpeg_parse_app14_data function)
    App14 present with parsing errors => Return -EINVAL from jpeg_parse_app14_data, also return from calling function (v4l2_jpeg_parse_header) when this error is met.

 drivers/media/v4l2-core/v4l2-jpeg.c | 47 +++++++++++++++++++++++++++--
 include/media/v4l2-jpeg.h           | 20 ++++++++++++
 2 files changed, 65 insertions(+), 2 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-jpeg.c b/drivers/media/v4l2-core/v4l2-jpeg.c
index 8947fd95c6f1..8d5fedb136dd 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

@@ -444,8 +445,44 @@ 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 = lp - 2 - 11;