[PATCH v14 06/32] drm/i915: Implement HDCP2.2 receiver authentication

[Ramalingam C <ramalingam.c@intel.com>]

Implements HDCP2.2 authentication for hdcp2.2 receivers, with
following steps:
	Authentication and Key exchange (AKE).
	Locality Check (LC).
	Session Key Exchange(SKE).
	DP Errata for stream type configuration for receivers.

At AKE, the HDCP Receiver’s public key certificate is verified by the
HDCP Transmitter. A Master Key k m is exchanged.

At LC, the HDCP Transmitter enforces locality on the content by
requiring that the Round Trip Time (RTT) between a pair of messages
is not more than 20 ms.

At SKE, The HDCP Transmitter exchanges Session Key ks with
the HDCP Receiver.

In DP HDCP2.2 encryption and decryption logics use the stream type as
one of the parameter. So Before enabling the Encryption DP HDCP2.2
receiver needs to be communicated with stream type. This is added to
spec as ERRATA.

This generic implementation is complete only with the hdcp2 specific
functions defined at hdcp_shim.

v2: Rebased.
v3:
  %s/PARING/PAIRING
  Coding style fixing [Uma]
v4:
  Rebased as part of patch reordering.
  Defined the functions for mei services. [Daniel]
v5:
  Redefined the mei service functions as per comp redesign.
  Required intel_hdcp members are defined [Sean Paul]
v6:
  Typo of cipher is Fixed [Uma]
  %s/uintxx_t/uxx
  Check for comp_master is removed.
v7:
  Adjust to the new interface.
  Avoid using bool structure members. [Tomas]
v8: Rebased.
v9:
  bool is used in struct intel_hdcp [Daniel]
  config_stream_type is redesigned [Daniel]
  Reviewed-by Uma.

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
---
 drivers/gpu/drm/i915/intel_drv.h  |  34 +++++++
 drivers/gpu/drm/i915/intel_hdcp.c | 197 +++++++++++++++++++++++++++++++++++---
 2 files changed, 216 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 2c99f88b71a7..5797ee0078f2 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -403,6 +403,22 @@ struct intel_hdcp_shim {
 	/* Detects whether sink is HDCP2.2 capable */
 	int (*hdcp_2_2_capable)(struct intel_digital_port *intel_dig_port,
 				bool *capable);
+
+	/* Write HDCP2.2 messages */
+	int (*write_2_2_msg)(struct intel_digital_port *intel_dig_port,
+			     void *buf, size_t size);
+
+	/* Read HDCP2.2 messages */
+	int (*read_2_2_msg)(struct intel_digital_port *intel_dig_port,
+			    u8 msg_id, void *buf, size_t size);
+
+	/*
+	 * Implementation of DP HDCP2.2 Errata for the communication of stream
+	 * type to Receivers. In DP HDCP2.2 Stream type is one of the input to
+	 * the HDCP2.2 Cipher for En/De-Cryption. Not applicable for HDMI.
+	 */
+	int (*config_stream_type)(struct intel_digital_port *intel_dig_port,
+				  bool is_repeater, u8 type);
 };
 
 struct intel_hdcp {
@@ -430,6 +446,24 @@ struct intel_hdcp {
 	 */
 	u8 content_type;
 	struct hdcp_port_data port_data;
+
+	bool is_paired;
+	bool is_repeater;
+
+	/*
+	 * Count of ReceiverID_List received. Initialized to 0 at AKE_INIT.
+	 * Incremented after processing the RepeaterAuth_Send_ReceiverID_List.
+	 * When it rolls over re-auth has to be triggered.
+	 */
+	u32 seq_num_v;
+
+	/*
+	 * Count of RepeaterAuth_Stream_Manage msg propagated.
+	 * Initialized to 0 on AKE_INIT. Incremented after every successful
+	 * transmission of RepeaterAuth_Stream_Manage message. When it rolls
+	 * over re-Auth has to be triggered.
+	 */
+	u32 seq_num_m;
 };
 
 struct intel_connector {
diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c
index 0b6ccb3d24fe..d63f620581ad 100644
--- a/drivers/gpu/drm/i915/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/intel_hdcp.c
@@ -17,6 +17,7 @@
 
 #define KEY_LOAD_TRIES	5
 #define ENCRYPT_STATUS_CHANGE_TIMEOUT_MS	50
+#define HDCP2_LC_RETRY_CNT			3
 
 static
 bool intel_hdcp_is_ksv_valid(u8 *ksv)
@@ -862,7 +863,7 @@ bool is_hdcp_supported(struct drm_i915_private *dev_priv, enum port port)
 	return INTEL_GEN(dev_priv) >= 9 && port < PORT_E;
 }
 
-static __attribute__((unused)) int
+static int
 hdcp2_prepare_ake_init(struct intel_connector *connector,
 		       struct hdcp2_ake_init *ake_data)
 {
@@ -887,7 +888,7 @@ hdcp2_prepare_ake_init(struct intel_connector *connector,
 	return ret;
 }
 
-static __attribute__((unused)) int
+static int
 hdcp2_verify_rx_cert_prepare_km(struct intel_connector *connector,
 				struct hdcp2_ake_send_cert *rx_cert,
 				bool *paired,
@@ -917,9 +918,8 @@ hdcp2_verify_rx_cert_prepare_km(struct intel_connector *connector,
 	return ret;
 }
 
-static __attribute__((unused)) int
-hdcp2_verify_hprime(struct intel_connector *connector,
-		    struct hdcp2_ake_send_hprime *rx_hprime)
+static int hdcp2_verify_hprime(struct intel_connector *connector,
+			       struct hdcp2_ake_send_hprime *rx_hprime)
 {
 	struct hdcp_port_data *data = &connector->hdcp.port_data;
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
@@ -942,7 +942,7 @@ hdcp2_verify_hprime(struct intel_connector *connector,
 	return ret;
 }
 
-static __attribute__((unused)) int
+static int
 hdcp2_store_pairing_info(struct intel_connector *connector,
 			 struct hdcp2_ake_send_pairing_info *pairing_info)
 {
@@ -967,7 +967,7 @@ hdcp2_store_pairing_info(struct intel_connector *connector,
 	return ret;
 }
 
-static __attribute__((unused)) int
+static int
 hdcp2_prepare_lc_init(struct intel_connector *connector,
 		      struct hdcp2_lc_init *lc_init)
 {
@@ -992,7 +992,7 @@ hdcp2_prepare_lc_init(struct intel_connector *connector,
 	return ret;
 }
 
-static __attribute__((unused)) int
+static int
 hdcp2_verify_lprime(struct intel_connector *connector,
 		    struct hdcp2_lc_send_lprime *rx_lprime)
 {
@@ -1017,9 +1017,8 @@ hdcp2_verify_lprime(struct intel_connector *connector,
 	return ret;
 }
 
-static __attribute__((unused))
-int hdcp2_prepare_skey(struct intel_connector *connector,
-		       struct hdcp2_ske_send_eks *ske_data)
+static int hdcp2_prepare_skey(struct intel_connector *connector,
+			      struct hdcp2_ske_send_eks *ske_data)
 {
 	struct hdcp_port_data *data = &connector->hdcp.port_data;
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
@@ -1096,8 +1095,7 @@ hdcp2_verify_mprime(struct intel_connector *connector,
 	return ret;
 }
 
-static __attribute__((unused))
-int hdcp2_authenticate_port(struct intel_connector *connector)
+static int hdcp2_authenticate_port(struct intel_connector *connector)
 {
 	struct hdcp_port_data *data = &connector->hdcp.port_data;
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
@@ -1146,11 +1144,180 @@ static int hdcp2_deauthenticate_port(struct intel_connector *connector)
 	return hdcp2_close_mei_session(connector);
 }
 
+/* Authentication flow starts from here */
+static int hdcp2_authentication_key_exchange(struct intel_connector *connector)
+{
+	struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
+	struct intel_hdcp *hdcp = &connector->hdcp;
+	union {
+		struct hdcp2_ake_init ake_init;
+		struct hdcp2_ake_send_cert send_cert;
+		struct hdcp2_ake_no_stored_km no_stored_km;
+		struct hdcp2_ake_send_hprime send_hprime;
+		struct hdcp2_ake_send_pairing_info pairing_info;
+	} msgs;
+	const struct intel_hdcp_shim *shim = hdcp->shim;
+	size_t size;
+	int ret;
+
+	/* Init for seq_num */
+	hdcp->seq_num_v = 0;
+	hdcp->seq_num_m = 0;
+
+	ret = hdcp2_prepare_ake_init(connector, &msgs.ake_init);
+	if (ret < 0)
+		return ret;
+
+	ret = shim->write_2_2_msg(intel_dig_port, &msgs.ake_init,
+				  sizeof(msgs.ake_init));
+	if (ret < 0)
+		return ret;
+
+	ret = shim->read_2_2_msg(intel_dig_port, HDCP_2_2_AKE_SEND_CERT,
+				 &msgs.send_cert, sizeof(msgs.send_cert));
+	if (ret < 0)
+		return ret;
+
+	if (msgs.send_cert.rx_caps[0] != HDCP_2_2_RX_CAPS_VERSION_VAL)
+		return -EINVAL;
+
+	hdcp->is_repeater = HDCP_2_2_RX_REPEATER(msgs.send_cert.rx_caps[2]);
+
+	/*
+	 * Here msgs.no_stored_km will hold msgs corresponding to the km
+	 * stored also.
+	 */
+	ret = hdcp2_verify_rx_cert_prepare_km(connector, &msgs.send_cert,
+					      &hdcp->is_paired,
+					      &msgs.no_stored_km, &size);
+	if (ret < 0)
+		return ret;
+
+	ret = shim->write_2_2_msg(intel_dig_port, &msgs.no_stored_km, size);
+	if (ret < 0)
+		return ret;
+
+	ret = shim->read_2_2_msg(intel_dig_port, HDCP_2_2_AKE_SEND_HPRIME,
+				 &msgs.send_hprime, sizeof(msgs.send_hprime));
+	if (ret < 0)
+		return ret;
+
+	ret = hdcp2_verify_hprime(connector, &msgs.send_hprime);
+	if (ret < 0)
+		return ret;
+
+	if (!hdcp->is_paired) {
+		/* Pairing is required */
+		ret = shim->read_2_2_msg(intel_dig_port,
+					 HDCP_2_2_AKE_SEND_PAIRING_INFO,
+					 &msgs.pairing_info,
+					 sizeof(msgs.pairing_info));
+		if (ret < 0)
+			return ret;
+
+		ret = hdcp2_store_pairing_info(connector, &msgs.pairing_info);
+		if (ret < 0)
+			return ret;
+		hdcp->is_paired = true;
+	}
+
+	return 0;
+}
+
+static int hdcp2_locality_check(struct intel_connector *connector)
+{
+	struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
+	struct intel_hdcp *hdcp = &connector->hdcp;
+	union {
+		struct hdcp2_lc_init lc_init;
+		struct hdcp2_lc_send_lprime send_lprime;
+	} msgs;
+	const struct intel_hdcp_shim *shim = hdcp->shim;
+	int tries = HDCP2_LC_RETRY_CNT, ret, i;
+
+	for (i = 0; i < tries; i++) {
+		ret = hdcp2_prepare_lc_init(connector, &msgs.lc_init);
+		if (ret < 0)
+			continue;
+
+		ret = shim->write_2_2_msg(intel_dig_port, &msgs.lc_init,
+				      sizeof(msgs.lc_init));
+		if (ret < 0)
+			continue;
+
+		ret = shim->read_2_2_msg(intel_dig_port,
+					 HDCP_2_2_LC_SEND_LPRIME,
+					 &msgs.send_lprime,
+					 sizeof(msgs.send_lprime));
+		if (ret < 0)
+			continue;
+
+		ret = hdcp2_verify_lprime(connector, &msgs.send_lprime);
+		if (!ret)
+			break;
+	}
+
+	return ret;
+}
+
+static int hdcp2_session_key_exchange(struct intel_connector *connector)
+{
+	struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
+	struct intel_hdcp *hdcp = &connector->hdcp;
+	struct hdcp2_ske_send_eks send_eks;
+	int ret;
+
+	ret = hdcp2_prepare_skey(connector, &send_eks);
+	if (ret < 0)
+		return ret;
+
+	ret = hdcp->shim->write_2_2_msg(intel_dig_port, &send_eks,
+					sizeof(send_eks));
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
 static int hdcp2_authenticate_sink(struct intel_connector *connector)
 {
-	DRM_ERROR("Sink authentication is done in subsequent patches\n");
+	struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
+	struct intel_hdcp *hdcp = &connector->hdcp;
+	const struct intel_hdcp_shim *shim = hdcp->shim;
+	int ret;
 
-	return -EINVAL;
+	ret = hdcp2_authentication_key_exchange(connector);
+	if (ret < 0) {
+		DRM_DEBUG_KMS("AKE Failed. Err : %d\n", ret);
+		return ret;
+	}
+
+	ret = hdcp2_locality_check(connector);
+	if (ret < 0) {
+		DRM_DEBUG_KMS("Locality Check failed. Err : %d\n", ret);
+		return ret;
+	}
+
+	ret = hdcp2_session_key_exchange(connector);
+	if (ret < 0) {
+		DRM_DEBUG_KMS("SKE Failed. Err : %d\n", ret);
+		return ret;
+	}
+
+	if (shim->config_stream_type) {
+		ret = shim->config_stream_type(intel_dig_port,
+					       hdcp->is_repeater,
+					       hdcp->content_type);
+		if (ret < 0)
+			return ret;
+	}
+
+	hdcp->port_data.streams[0].stream_type = hdcp->content_type;
+	ret = hdcp2_authenticate_port(connector);
+	if (ret < 0)
+		return ret;
+
+	return ret;
 }
 
 static int hdcp2_enable_encryption(struct intel_connector *connector)
-- 
2.7.4

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