msm: mdss: hdmi: add checksum for HDR infoframe

Checksum for the HDR infoframe is set to zero by default
as this is not a mandatory field as per the HDMI spec.

However certain HDMI sinks still expect a non-zero
checksum. Otherwise they disregard the infoframe
and the sink does not enter HDR mode despite other fields
of the infoframe being valid.

Add a valid checksum to the HDR infoframe to improve
interoperability of our HDR solution for HDMI.

Change-Id: Ic715981c458384e75f3ab1af69080478ab852d37
Signed-off-by: Narender Ankam <nankam@codeaurora.org>

1 files changed, 105 insertions, 1 deletions

diff --git a/drivers/video/fbdev/msm/mdss_hdmi_tx.c b/drivers/video/fbdev/msm/mdss_hdmi_tx.c
index af08edf13d87..e0fcfec614b5 100644
--- a/drivers/video/fbdev/msm/mdss_hdmi_tx.c
+++ b/drivers/video/fbdev/msm/mdss_hdmi_tx.c
@@ -23,6 +23,7 @@
 #include <linux/hdcp_qseecom.h>
 #include <linux/msm_mdp.h>
 #include <linux/msm_ext_display.h>
+#include <linux/hdmi.h>
 
 #define REG_DUMP 0
 
@@ -3038,6 +3039,96 @@ static void hdmi_tx_phy_reset(struct hdmi_tx_ctrl *hdmi_ctrl)
 		DSS_REG_W_ND(io, HDMI_PHY_CTRL, val | SW_RESET_PLL);
 } /* hdmi_tx_phy_reset */
 
+static u8 calc_infoframe_checksum(u8 *ptr, size_t size)
+{
+	u8 csum = 0;
+	size_t i;
+
+	/* compute checksum */
+	for (i = 0; i < size; i++)
+		csum += ptr[i];
+
+	return 256 - csum;
+}
+
+static u8 hdmi_panel_set_hdr_checksum(struct mdp_hdr_stream *hdr_meta)
+{
+	u8 *buff;
+	u8 *ptr;
+	u32 length;
+	u32 size;
+	u32 checksum = 0;
+	u32 const type_code = 0x87;
+	u32 const version = 0x01;
+	u32 const descriptor_id = 0x00;
+
+	/* length of metadata is 26 bytes */
+	length = 0x1a;
+	/* add 4 bytes for the header */
+	size = length + HDMI_INFOFRAME_HEADER_SIZE;
+
+	buff = kzalloc(size, GFP_KERNEL);
+
+	if (!buff) {
+		DEV_ERR("invalid buff\n");
+		goto err_alloc;
+	}
+
+	ptr = buff;
+
+	buff[0] = type_code;
+	buff[1] = version;
+	buff[2] = length;
+	buff[3] = 0;
+	/* start infoframe payload */
+	buff += HDMI_INFOFRAME_HEADER_SIZE;
+
+	buff[0] = hdr_meta->eotf;
+	buff[1] = descriptor_id;
+
+	buff[2] = hdr_meta->display_primaries_x[0] & 0xff;
+	buff[3] = hdr_meta->display_primaries_x[0] >> 8;
+
+	buff[4] = hdr_meta->display_primaries_x[1] & 0xff;
+	buff[5] = hdr_meta->display_primaries_x[1] >> 8;
+
+	buff[6] = hdr_meta->display_primaries_x[2] & 0xff;
+	buff[7] = hdr_meta->display_primaries_x[2] >> 8;
+
+	buff[8] = hdr_meta->display_primaries_y[0] & 0xff;
+	buff[9] = hdr_meta->display_primaries_y[0] >> 8;
+
+	buff[10] = hdr_meta->display_primaries_y[1] & 0xff;
+	buff[11] = hdr_meta->display_primaries_y[1] >> 8;
+
+	buff[12] = hdr_meta->display_primaries_y[2] & 0xff;
+	buff[13] = hdr_meta->display_primaries_y[2] >> 8;
+
+	buff[14] = hdr_meta->white_point_x & 0xff;
+	buff[15] = hdr_meta->white_point_x >> 8;
+	buff[16] = hdr_meta->white_point_y & 0xff;
+	buff[17] = hdr_meta->white_point_y >> 8;
+
+	buff[18] = hdr_meta->max_luminance & 0xff;
+	buff[19] = hdr_meta->max_luminance >> 8;
+
+	buff[20] = hdr_meta->min_luminance & 0xff;
+	buff[21] = hdr_meta->min_luminance >> 8;
+
+	buff[22] = hdr_meta->max_content_light_level & 0xff;
+	buff[23] = hdr_meta->max_content_light_level >> 8;
+
+	buff[24] = hdr_meta->max_average_light_level & 0xff;
+	buff[25] = hdr_meta->max_average_light_level >> 8;
+
+	checksum = calc_infoframe_checksum(ptr, size);
+
+	kfree(ptr);
+
+err_alloc:
+	return checksum;
+}
+
 static void hdmi_panel_set_hdr_infoframe(struct hdmi_tx_ctrl *ctrl)
 {
 	u32 packet_payload = 0;
@@ -3047,8 +3138,10 @@ static void hdmi_panel_set_hdr_infoframe(struct hdmi_tx_ctrl *ctrl)
 	u32 const version = 0x01;
 	u32 const length = 0x1a;
 	u32 const descriptor_id = 0x00;
+	u8 checksum = 0;
 	struct dss_io_data *io = NULL;
 
+
 	if (!ctrl) {
 		pr_err("%s: invalid input\n", __func__);
 		return;
@@ -3069,7 +3162,18 @@ static void hdmi_panel_set_hdr_infoframe(struct hdmi_tx_ctrl *ctrl)
 	packet_header = type_code | (version << 8) | (length << 16);
 	DSS_REG_W(io, HDMI_GENERIC0_HDR, packet_header);
 
-	packet_payload = (ctrl->hdr_ctrl.hdr_stream.eotf << 8);
+	/**
+	 * Checksum is not a mandatory field for
+	 * the HDR infoframe as per CEA-861-3 specification.
+	 * However some HDMI sinks still expect a
+	 * valid checksum to be included as part of
+	 * the infoframe. Hence compute and add
+	 * the checksum to improve sink interoperability
+	 * for our HDR solution on HDMI.
+	 */
+	checksum = hdmi_panel_set_hdr_checksum(&ctrl->hdr_ctrl.hdr_stream);
+
+	packet_payload = ((ctrl->hdr_ctrl.hdr_stream.eotf << 8) | checksum);
 	if (hdmi_tx_metadata_type_one(ctrl)) {
 		packet_payload |=
 			(descriptor_id << 16)