[v10 11/12] video/hdmi: Add Unpack function for DRM infoframe

[Uma Shankar <uma.shankar@xxxxxxxxx>]

Added unpack function for DRM infoframe for dynamic
range and mastering infoframe readout.

v2: Addressed Ville's review comments.

Suggested-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Signed-off-by: Uma Shankar <uma.shankar@xxxxxxxxx>
---
 drivers/video/hdmi.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/hdmi.h |  1 +
 2 files changed, 71 insertions(+)

diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c
index c5ecd16..b99ba01 100644
--- a/drivers/video/hdmi.c
+++ b/drivers/video/hdmi.c
@@ -675,6 +675,9 @@ static int hdmi_drm_infoframe_check_only(const struct hdmi_drm_infoframe *frame)
 	    frame->version != 1)
 		return -EINVAL;
 
+	if (frame->length != HDMI_DRM_INFOFRAME_SIZE)
+		return -EINVAL;
+
 	return 0;
 }
 
@@ -1802,6 +1805,70 @@ static int hdmi_audio_infoframe_unpack(struct hdmi_audio_infoframe *frame,
 }
 
 /**
+ * hdmi_drm_infoframe_unpack() - unpack binary buffer to a HDMI DRM infoframe
+ * @frame: HDMI DRM infoframe
+ * @buffer: source buffer
+ * @size: size of buffer
+ *
+ * Unpacks the information contained in binary @buffer into a structured
+ * @frame of the HDMI Dynamic Range and Mastering (DRM) information frame.
+ * Also verifies the checksum as required by section 5.3.5 of the HDMI 1.4
+ * specification.
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+static int hdmi_drm_infoframe_unpack(struct hdmi_drm_infoframe *frame,
+				     const void *buffer, size_t size)
+{
+	const u8 *ptr = buffer;
+	const u8 *temp;
+	u8 x_lsb, x_msb;
+	u8 y_lsb, y_msb;
+	int ret;
+	int i;
+
+	if (size < HDMI_INFOFRAME_SIZE(DRM))
+		return -EINVAL;
+
+	if (ptr[0] != HDMI_INFOFRAME_TYPE_DRM ||
+	    ptr[1] != 1 ||
+	    ptr[2] != HDMI_DRM_INFOFRAME_SIZE)
+		return -EINVAL;
+
+	if (hdmi_infoframe_checksum(buffer, HDMI_INFOFRAME_SIZE(DRM)) != 0)
+		return -EINVAL;
+
+	ret = hdmi_drm_infoframe_init(frame);
+	if (ret)
+		return ret;
+
+	ptr += HDMI_INFOFRAME_HEADER_SIZE;
+
+	frame->eotf = ptr[0] & 0x7;
+	frame->metadata_type = ptr[1] & 0x7;
+
+	temp = ptr + 2;
+	for (i = 0; i < 3; i++) {
+		x_lsb = *temp++;
+		x_msb = *temp++;
+		frame->display_primaries[i].x =  (x_msb << 8) | x_lsb;
+		y_lsb = *temp++;
+		y_msb = *temp++;
+		frame->display_primaries[i].y = (y_msb << 8) | y_lsb;
+	}
+
+	frame->white_point.x = (ptr[15] << 8) | ptr[14];
+	frame->white_point.y = (ptr[17] << 8) | ptr[16];
+
+	frame->max_display_mastering_luminance = (ptr[19] << 8) | ptr[18];
+	frame->min_display_mastering_luminance = (ptr[21] << 8) | ptr[20];
+	frame->max_cll = (ptr[23] << 8) | ptr[22];
+	frame->max_fall = (ptr[25] << 8) | ptr[24];
+
+	return 0;
+}
+
+/**
  * hdmi_infoframe_unpack() - unpack binary buffer to a HDMI infoframe
  * @frame: HDMI infoframe
  * @buffer: source buffer
@@ -1827,6 +1894,9 @@ int hdmi_infoframe_unpack(union hdmi_infoframe *frame,
 	case HDMI_INFOFRAME_TYPE_AVI:
 		ret = hdmi_avi_infoframe_unpack(&frame->avi, buffer, size);
 		break;
+	case HDMI_INFOFRAME_TYPE_DRM:
+		ret = hdmi_drm_infoframe_unpack(&frame->drm, buffer, size);
+		break;
 	case HDMI_INFOFRAME_TYPE_SPD:
 		ret = hdmi_spd_infoframe_unpack(&frame->spd, buffer, size);
 		break;
diff --git a/include/linux/hdmi.h b/include/linux/hdmi.h
index 3d7f10f..ee55ba5 100644
--- a/include/linux/hdmi.h
+++ b/include/linux/hdmi.h
@@ -56,6 +56,7 @@ enum hdmi_infoframe_type {
 #define HDMI_AVI_INFOFRAME_SIZE    13
 #define HDMI_SPD_INFOFRAME_SIZE    25
 #define HDMI_AUDIO_INFOFRAME_SIZE  10
+#define HDMI_DRM_INFOFRAME_SIZE    26
 
 #define HDMI_INFOFRAME_SIZE(type)	\
 	(HDMI_INFOFRAME_HEADER_SIZE + HDMI_ ## type ## _INFOFRAME_SIZE)
-- 
1.9.1

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