[PATCH v2 3/5] drm/i915: terminate reauth at stream management failure

[Ramalingam C]

As per the HDCP2.2 compliance test 1B-10 expectation, when stream
management for a repeater fails, we retry thrice and when it fails
in all retries, HDCP2.2 reauthentication aborted at kernel.

v2:
  seq_num_m++ is extended for steam management failures too.[Anshuman]
v3:
  use drm_dbg_kms instead of DRM_DEBUG_KMS [Anshuman]
v4:
  dev_priv is used as i915 [JaniN]

Signed-off-by: Ramalingam C <ramalingam.c at intel.com>
---
 drivers/gpu/drm/i915/display/intel_hdcp.c | 75 ++++++++++++++---------
 1 file changed, 46 insertions(+), 29 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index 30e0a3aa9d57..b24d12efae0a 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -1380,7 +1380,7 @@ static int hdcp2_session_key_exchange(struct intel_connector *connector)
 }
 
 static
-int hdcp2_propagate_stream_management_info(struct intel_connector *connector)
+int _hdcp2_propagate_stream_management_info(struct intel_connector *connector)
 {
 	struct intel_digital_port *intel_dig_port = intel_attached_dig_port(connector);
 	struct intel_hdcp *hdcp = &connector->hdcp;
@@ -1406,28 +1406,25 @@ int hdcp2_propagate_stream_management_info(struct intel_connector *connector)
 	ret = shim->write_2_2_msg(intel_dig_port, &msgs.stream_manage,
 				  sizeof(msgs.stream_manage));
 	if (ret < 0)
-		return ret;
+		goto err_exit;
 
 	ret = shim->read_2_2_msg(intel_dig_port, HDCP_2_2_REP_STREAM_READY,
 				 &msgs.stream_ready, sizeof(msgs.stream_ready));
 	if (ret < 0)
-		return ret;
+		goto err_exit;
 
 	hdcp->port_data.seq_num_m = hdcp->seq_num_m;
 	hdcp->port_data.streams[0].stream_type = hdcp->content_type;
-
 	ret = hdcp2_verify_mprime(connector, &msgs.stream_ready);
-	if (ret < 0)
-		return ret;
 
+err_exit:
 	hdcp->seq_num_m++;
-
 	if (hdcp->seq_num_m > HDCP_2_2_SEQ_NUM_MAX) {
 		DRM_DEBUG_KMS("seq_num_m roll over.\n");
-		return -1;
+		ret = -1;
 	}
 
-	return 0;
+	return ret;
 }
 
 static
@@ -1492,17 +1489,6 @@ int hdcp2_authenticate_repeater_topology(struct intel_connector *connector)
 	return 0;
 }
 
-static int hdcp2_authenticate_repeater(struct intel_connector *connector)
-{
-	int ret;
-
-	ret = hdcp2_authenticate_repeater_topology(connector);
-	if (ret < 0)
-		return ret;
-
-	return hdcp2_propagate_stream_management_info(connector);
-}
-
 static int hdcp2_authenticate_sink(struct intel_connector *connector)
 {
 	struct intel_digital_port *intel_dig_port = intel_attached_dig_port(connector);
@@ -1537,18 +1523,13 @@ static int hdcp2_authenticate_sink(struct intel_connector *connector)
 	}
 
 	if (hdcp->is_repeater) {
-		ret = hdcp2_authenticate_repeater(connector);
+		ret = hdcp2_authenticate_repeater_topology(connector);
 		if (ret < 0) {
 			DRM_DEBUG_KMS("Repeater Auth Failed. Err: %d\n", ret);
 			return ret;
 		}
 	}
 
-	hdcp->port_data.streams[0].stream_type = hdcp->content_type;
-	ret = hdcp2_authenticate_port(connector);
-	if (ret < 0)
-		return ret;
-
 	return ret;
 }
 
@@ -1626,14 +1607,50 @@ static int hdcp2_disable_encryption(struct intel_connector *connector)
 	return ret;
 }
 
+static int
+hdcp2_propagate_stream_management_info(struct intel_connector *connector)
+{
+	struct drm_i915_private *i915 = to_i915(connector->base.dev);
+	int i, tries = 3, ret;
+
+	if (!connector->hdcp.is_repeater)
+		return 0;
+
+	for (i = 0; i < tries; i++) {
+		ret = _hdcp2_propagate_stream_management_info(connector);
+		if (!ret)
+			break;
+
+		drm_dbg_kms(&i915->drm,
+			    "HDCP2 stream management %d of %d Failed.(%d)\n",
+			    i + 1, tries, ret);
+	}
+
+	return ret;
+}
+
 static int hdcp2_authenticate_and_encrypt(struct intel_connector *connector)
 {
+	struct drm_i915_private *i915 = to_i915(connector->base.dev);
+	struct intel_hdcp *hdcp = &connector->hdcp;
 	int ret, i, tries = 3;
 
 	for (i = 0; i < tries; i++) {
 		ret = hdcp2_authenticate_sink(connector);
-		if (!ret)
-			break;
+		if (!ret) {
+			ret = hdcp2_propagate_stream_management_info(connector);
+			if (!ret) {
+				hdcp->port_data.streams[0].stream_type =
+							hdcp->content_type;
+				ret = hdcp2_authenticate_port(connector);
+				if (!ret)
+					break;
+			} else {
+				drm_dbg_kms(&i915->drm,
+					    "HDCP2 stream management failed\n");
+				break;
+			}
+		}
 
 		/* Clearing the mei hdcp session */
 		DRM_DEBUG_KMS("HDCP2.2 Auth %d of %d Failed.(%d)\n",
@@ -1642,7 +1659,7 @@ static int hdcp2_authenticate_and_encrypt(struct intel_connector *connector)
 			DRM_DEBUG_KMS("Port deauth failed.\n");
 	}
 
-	if (i != tries) {
+	if (!ret) {
 		/*
 		 * Ensuring the required 200mSec min time interval between
 		 * Session Key Exchange and encryption.
-- 
2.20.1