[PATCH v6 18/18] drm/i915/hdcp: Enable HDCP 2.2 MST support

[Anshuman Gupta]

Enable HDCP 2.2 over DP MST.
Authenticate and enable port encryption only once for
an active HDCP 2.2 session, once port is authenticated
and encrypted enable encryption for each stream that
requires encryption on this port.

Similarly disable the stream encryption for each encrypted
stream, once all encrypted stream encryption is disabled,
disable the port HDCP encryption and deauthenticate the port.

v2:
- Add connector details in drm_err. [Ram]
- 's/port_auth/hdcp_auth_status'. [Ram]
- Added a debug print for stream enc.
v3:
- uniformity for connector detail in DMESG. [Ram]

Cc: Ramalingam C <ramalingam.c at intel.com>
Reviewed-by: Uma Shankar <uma.shankar at intel.com>
Tested-by: Karthik B S <karthik.b.s at intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta at intel.com>
---
 drivers/gpu/drm/i915/display/intel_hdcp.c | 53 ++++++++++++++++++++++-
 1 file changed, 51 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index 65dd39b44688..4b221c298835 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -1700,6 +1700,36 @@ static int hdcp2_authenticate_sink(struct intel_connector *connector)
 	return ret;
 }
 
+static int hdcp2_enable_stream_encryption(struct intel_connector *connector)
+{
+	struct intel_digital_port *dig_port = intel_attached_dig_port(connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_hdcp *hdcp = &connector->hdcp;
+	enum transcoder cpu_transcoder = hdcp->cpu_transcoder;
+	enum port port = dig_port->base.port;
+	int ret = 0;
+
+	if (!(intel_de_read(dev_priv, HDCP2_STATUS(dev_priv, cpu_transcoder, port)) &
+			    LINK_ENCRYPTION_STATUS)) {
+		drm_err(&dev_priv->drm, "[%s:%d] HDCP 2.2 Link is not encrypted\n",
+			connector->base.name, connector->base.base.id);
+		return -EPERM;
+	}
+
+	if (hdcp->shim->stream_2_2_encryption) {
+		ret = hdcp->shim->stream_2_2_encryption(connector, true);
+		if (ret) {
+			drm_err(&dev_priv->drm, "[%s:%d] Failed to enable HDCP 2.2 stream enc\n",
+				connector->base.name, connector->base.base.id);
+			return ret;
+		}
+		drm_dbg_kms(&dev_priv->drm, "HDCP 2.2 transcoder: %s stream encrypted\n",
+			    transcoder_name(hdcp->stream_transcoder));
+	}
+
+	return ret;
+}
+
 static int hdcp2_enable_encryption(struct intel_connector *connector)
 {
 	struct intel_digital_port *dig_port = intel_attached_dig_port(connector);
@@ -1838,7 +1868,7 @@ static int hdcp2_authenticate_and_encrypt(struct intel_connector *connector)
 			drm_dbg_kms(&i915->drm, "Port deauth failed.\n");
 	}
 
-	if (!ret) {
+	if (!ret && !dig_port->hdcp_auth_status) {
 		/*
 		 * Ensuring the required 200mSec min time interval between
 		 * Session Key Exchange and encryption.
@@ -1853,6 +1883,8 @@ static int hdcp2_authenticate_and_encrypt(struct intel_connector *connector)
 		}
 	}
 
+	ret = hdcp2_enable_stream_encryption(connector);
+
 	return ret;
 }
 
@@ -1898,11 +1930,26 @@ static int _intel_hdcp2_disable(struct intel_connector *connector)
 	struct intel_digital_port *dig_port = intel_attached_dig_port(connector);
 	struct drm_i915_private *i915 = to_i915(connector->base.dev);
 	struct hdcp_port_data *data = &dig_port->hdcp_port_data;
+	struct intel_hdcp *hdcp = &connector->hdcp;
 	int ret;
 
 	drm_dbg_kms(&i915->drm, "[%s:%d] HDCP2.2 is being Disabled\n",
 		    connector->base.name, connector->base.base.id);
 
+	if (hdcp->shim->stream_2_2_encryption) {
+		ret = hdcp->shim->stream_2_2_encryption(connector, false);
+		if (ret) {
+			drm_err(&i915->drm, "[%s:%d] Failed to disable HDCP 2.2 stream enc\n",
+				connector->base.name, connector->base.base.id);
+			return ret;
+		}
+		drm_dbg_kms(&i915->drm, "HDCP 2.2 transcoder: %s stream encryption disabled\n",
+			    transcoder_name(hdcp->stream_transcoder));
+	}
+
+	if (dig_port->num_hdcp_streams > 0)
+		return ret;
+
 	ret = hdcp2_disable_encryption(connector);
 
 	if (hdcp2_deauthenticate_port(connector) < 0)
@@ -1926,6 +1973,7 @@ static int intel_hdcp2_check_link(struct intel_connector *connector)
 	int ret = 0;
 
 	mutex_lock(&hdcp->mutex);
+	mutex_lock(&dig_port->hdcp_mutex);
 	cpu_transcoder = hdcp->cpu_transcoder;
 
 	/* hdcp2_check_link is expected only when HDCP2.2 is Enabled */
@@ -2003,6 +2051,7 @@ static int intel_hdcp2_check_link(struct intel_connector *connector)
 	}
 
 out:
+	mutex_unlock(&dig_port->hdcp_mutex);
 	mutex_unlock(&hdcp->mutex);
 	return ret;
 }
@@ -2184,7 +2233,7 @@ int intel_hdcp_init(struct intel_connector *connector,
 	if (!shim)
 		return -EINVAL;
 
-	if (is_hdcp2_supported(dev_priv) && !connector->mst_port)
+	if (is_hdcp2_supported(dev_priv))
 		intel_hdcp2_init(connector, dig_port, shim);
 
 	ret =
-- 
2.26.2