[PATCH v5 07/17] drm/i915/hdcp: Enable HDCP 1.4 stream encryption

[Anshuman Gupta]

Enable HDCP 1.4 DP MST stream encryption.

Enable stream encryption once encryption is enabled on
the DP transport driving the link for each stream which
has requested encryption.

Disable stream encryption for each stream that no longer
requires encryption before disabling HDCP encryption on
the link.

v2:
- Added debug print for stream encryption.
- Disable the hdcp on port after disabling last stream
  encryption.
v3:
- Cosmetic change, removed the value less comment. [Uma]
v4:
- Split the Gen12 HDCP enablement patch. [Ram]
- Add connector details in drm_err.

Cc: Ramalingam C <ramalingam.c at intel.com>
Reviewed-by: Uma Shankar <uma.shankar at intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta at intel.com>
---
 drivers/gpu/drm/i915/display/intel_hdcp.c | 45 ++++++++++++++++-------
 1 file changed, 31 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index 0322a83c151d..e12bd0ac9fb5 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -612,7 +612,12 @@ int intel_hdcp_auth_downstream(struct intel_connector *connector)
 	return ret;
 }
 
-/* Implements Part 1 of the HDCP authorization procedure */
+/*
+ * Implements Part 1 of the HDCP authorization procedure.
+ * Authentication Part 1 steps for Multi-stream DisplayPort.
+ * Step 1. Auth Part 1 sequence on the driving MST Trasport Link.
+ * Step 2. Enable encryption for each stream that requires encryption.
+ */
 static int intel_hdcp_auth(struct intel_connector *connector)
 {
 	struct intel_digital_port *dig_port = intel_attached_dig_port(connector);
@@ -766,10 +771,17 @@ static int intel_hdcp_auth(struct intel_connector *connector)
 		return -ETIMEDOUT;
 	}
 
-	/*
-	 * XXX: If we have MST-connected devices, we need to enable encryption
-	 * on those as well.
-	 */
+	/* DP MST Auth Part 1 Step 2.a and Step 2.b */
+	if (shim->stream_encryption) {
+		ret = shim->stream_encryption(connector, true);
+		if (ret) {
+			drm_err(&dev_priv->drm, "[CONNECTOR:%d:%s] Failed to enable HDCP 1.4 stream enc\n",
+				connector->base.base.id, connector->base.name);
+			return ret;
+		}
+		drm_dbg_kms(&dev_priv->drm, "HDCP 1.4 transcoder: %s stream encrypted\n",
+			    transcoder_name(hdcp->stream_transcoder));
+	}
 
 	if (repeater_present)
 		return intel_hdcp_auth_downstream(connector);
@@ -791,18 +803,23 @@ static int _intel_hdcp_disable(struct intel_connector *connector)
 	drm_dbg_kms(&dev_priv->drm, "[%s:%d] HDCP is being disabled...\n",
 		    connector->base.name, connector->base.base.id);
 
+	if (hdcp->shim->stream_encryption) {
+		ret = hdcp->shim->stream_encryption(connector, false);
+		if (ret) {
+			drm_err(&dev_priv->drm, "[CONNECTOR:%d:%s] Failed to disable HDCP 1.4 stream enc\n",
+				connector->base.base.id, connector->base.name);
+			return ret;
+		}
+		drm_dbg_kms(&dev_priv->drm, "HDCP 1.4 transcoder: %s stream encryption disabled\n",
+			    transcoder_name(hdcp->stream_transcoder));
+	}
+
 	/*
-	 * If there are other connectors on this port using HDCP, don't disable
-	 * it. Instead, toggle the HDCP signalling off on that particular
-	 * connector/pipe and exit.
+	 * If there are other connectors on this port using HDCP, don't disable it.
+	 * Repeat steps 1-2 for each stream that no longer requires encryption.
 	 */
-	if (dig_port->num_hdcp_streams > 0) {
-		ret = hdcp->shim->toggle_signalling(dig_port,
-						    cpu_transcoder, false);
-		if (ret)
-			DRM_ERROR("Failed to disable HDCP signalling\n");
+	if (dig_port->num_hdcp_streams > 0)
 		return ret;
-	}
 
 	hdcp->hdcp_encrypted = false;
 	intel_de_write(dev_priv, HDCP_CONF(dev_priv, cpu_transcoder, port), 0);
-- 
2.26.2