msm: mdss: hdmi: Avoid unnecessary BCAPS read

Don't read BCAPS (downstream device's capability register) in second
part of authentication to check if the attached downstream device is
a repeater or not. BCAPS register is already read in first part of
authentication. Reuse it's value for this purpose. This avoids any
unnecessary delays and possible arbitration for DDC line between
hardware (for third part of authentication) and software which
sometimes results in HDCP compliance 1A-07 failure or not judged.

Change-Id: I19a95e029aa31168382926f7d43920e6e24a917b
Signed-off-by: Ajay Singh Parmar <aparmar@codeaurora.org>

1 files changed, 20 insertions, 39 deletions

diff --git a/drivers/video/fbdev/msm/mdss_hdmi_hdcp.c b/drivers/video/fbdev/msm/mdss_hdmi_hdcp.c
index 80b27ed63b21..ca21b51fb0cd 100644
--- a/drivers/video/fbdev/msm/mdss_hdmi_hdcp.c
+++ b/drivers/video/fbdev/msm/mdss_hdmi_hdcp.c
@@ -289,6 +289,10 @@ static int hdmi_hdcp_authentication_part1(struct hdmi_hdcp_ctrl *hdcp_ctrl)
 	}
 	DEV_DBG("%s: %s: BCAPS=%02x\n", __func__, HDCP_STATE_NAME, bcaps);
 
+	/* receiver (0), repeater (1) */
+	hdcp_ctrl->current_tp.ds_type =
+		(bcaps & BIT(6)) >> 6 ? DS_REPEATER : DS_RECEIVER;
+
 	/*
 	 * HDCP setup prior to enabling HDCP_CTRL.
 	 * Setup seed values for random number An.
@@ -644,40 +648,12 @@ static int hdmi_hdcp_authentication_part2(struct hdmi_hdcp_ctrl *hdcp_ctrl)
 	memset(ksv_fifo, 0,
 		sizeof(hdcp_ctrl->current_tp.ksv_list));
 
-	/* Read BCAPS at offset 0x40 */
-	memset(&ddc_data, 0, sizeof(ddc_data));
-	ddc_data.dev_addr = 0x74;
-	ddc_data.offset = 0x40;
-	ddc_data.data_buf = &bcaps;
-	ddc_data.data_len = 1;
-	ddc_data.request_len = 1;
-	ddc_data.retry = 5;
-	ddc_data.what = "Bcaps";
-	ddc_data.no_align = false;
-	rc = hdmi_ddc_read(hdcp_ctrl->init_data.ddc_ctrl, &ddc_data);
-	if (rc) {
-		DEV_ERR("%s: %s: BCAPS read failed\n", __func__,
-			HDCP_STATE_NAME);
-		goto error;
-	}
-	DEV_DBG("%s: %s: BCAPS=%02x (%s)\n", __func__, HDCP_STATE_NAME, bcaps,
-		(bcaps & BIT(6)) ? "repeater" : "no repeater");
-
-	/* receiver (0), repeater (1) */
-	hdcp_ctrl->current_tp.ds_type =
-		(bcaps & BIT(6)) >> 6 ? DS_REPEATER : DS_RECEIVER;
-
-	/* if REPEATER (Bit 6), perform Part2 Authentication */
-	if (!(bcaps & BIT(6))) {
-		DEV_INFO("%s: %s: auth part II skipped, no repeater\n",
-			__func__, HDCP_STATE_NAME);
-		return 0;
-	}
-
-	/* Wait until READY bit is set in BCAPS */
+	/*
+	 * Wait until READY bit is set in BCAPS, as per HDCP specifications
+	 * maximum permitted time to check for READY bit is five seconds.
+	 */
 	timeout_count = 50;
-	while (!(bcaps & BIT(5)) && timeout_count) {
-		msleep(100);
+	do {
 		timeout_count--;
 		/* Read BCAPS at offset 0x40 */
 		memset(&ddc_data, 0, sizeof(ddc_data));
@@ -695,7 +671,8 @@ static int hdmi_hdcp_authentication_part2(struct hdmi_hdcp_ctrl *hdcp_ctrl)
 				HDCP_STATE_NAME);
 			goto error;
 		}
-	}
+		msleep(100);
+	} while (!(bcaps & BIT(5)) && timeout_count);
 
 	/* Read BSTATUS at offset 0x41 */
 	memset(&ddc_data, 0, sizeof(ddc_data));
@@ -976,11 +953,15 @@ static void hdmi_hdcp_auth_work(struct work_struct *work)
 		goto error;
 	}
 
-	rc = hdmi_hdcp_authentication_part2(hdcp_ctrl);
-	if (rc) {
-		DEV_DBG("%s: %s: HDCP Auth Part II failed\n", __func__,
-			HDCP_STATE_NAME);
-		goto error;
+	if (hdcp_ctrl->current_tp.ds_type == DS_REPEATER) {
+		rc = hdmi_hdcp_authentication_part2(hdcp_ctrl);
+		if (rc) {
+			DEV_DBG("%s: %s: HDCP Auth Part II failed\n", __func__,
+				HDCP_STATE_NAME);
+			goto error;
+		}
+	} else {
+		DEV_INFO("%s: Downstream device is not a repeater\n", __func__);
 	}
 	/* Disabling software DDC before going into part3 to make sure
 	 * there is no Arbitration between software and hardware for DDC */