[PATCH v2 26/42] drm/i915: Implement HDCP2.2 repeater authentication

[Ramalingam C]

Implements the HDCP2.2 repeaters authentication steps such as verifying
the downstream topology and sending stream management information.

v2:
  Rebased.

Signed-off-by: Ramalingam C <ramalingam.c at intel.com>
---
 drivers/gpu/drm/i915/intel_hdcp.c | 135 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 135 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c
index 6fb9fd4d6e1c..53314f8e491a 100644
--- a/drivers/gpu/drm/i915/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/intel_hdcp.c
@@ -1145,6 +1145,135 @@ static int hdcp2_session_key_exchange(struct intel_connector *connector)
 	return 0;
 }
 
+/*
+ * Lib endianness functions are aligned for 16/32/64 bits. Since here sequence
+ * num is 24bits developed a small conversion function.
+ */
+static inline void reverse_endianness(u8 *dest, size_t dst_sz, u8 *src)
+{
+	u32 index;
+
+	if (dest != NULL && dst_sz != 0) {
+		for (index = 0; index < dst_sz && index < sizeof(u32);
+		     index++) {
+			dest[dst_sz - index - 1] = src[index];
+		}
+	}
+}
+
+static
+int hdcp2_propagate_stream_management_info(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_rep_stream_manage stream_manage;
+		struct hdcp2_rep_stream_ready stream_ready;
+	} msgs;
+	const struct intel_hdcp_shim *shim = hdcp->hdcp_shim;
+	int ret;
+
+	/* Prepare RepeaterAuth_Stream_Manage msg */
+	msgs.stream_manage.msg_id = HDCP_2_2_REP_STREAM_MANAGE;
+	reverse_endianness(msgs.stream_manage.seq_num_m, HDCP_2_2_SEQ_NUM_LEN,
+			   (u8 *)&hdcp->seq_num_m);
+
+	/* K no of streams is fixed as 1. Stored as big-endian. */
+	msgs.stream_manage.k = __swab16(1);
+
+	/* For HDMI this is forced to be 0x0. For DP SST also this is 0x0. */
+	msgs.stream_manage.streams[0].stream_id = 0;
+	msgs.stream_manage.streams[0].stream_type = hdcp->content_type;
+
+	/* Send it to Repeater */
+	ret = shim->write_2_2_msg(intel_dig_port, &msgs.stream_manage,
+				  sizeof(msgs.stream_manage));
+	if (ret < 0)
+		return ret;
+
+	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;
+
+	hdcp->mei_data.seq_num_m = hdcp->seq_num_m;
+	hdcp->mei_data.streams[0].stream_type = hdcp->content_type;
+
+	ret = hdcp2_verify_mprime(hdcp,	&msgs.stream_ready);
+	if (ret < 0)
+		return ret;
+
+	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;
+	}
+	return 0;
+}
+
+static
+int hdcp2_authenticate_repeater_topology(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_rep_send_receiverid_list recvid_list;
+		struct hdcp2_rep_send_ack rep_ack;
+	} msgs;
+	const struct intel_hdcp_shim *shim = hdcp->hdcp_shim;
+	uint8_t *rx_info;
+	uint32_t seq_num_v;
+	int ret;
+
+	ret = shim->read_2_2_msg(intel_dig_port, HDCP_2_2_REP_SEND_RECVID_LIST,
+				 &msgs.recvid_list, sizeof(msgs.recvid_list));
+	if (ret < 0)
+		return ret;
+
+	rx_info = msgs.recvid_list.rx_info;
+
+	if (HDCP_2_2_MAX_CASCADE_EXCEEDED(rx_info[1]) ||
+	    HDCP_2_2_MAX_DEVS_EXCEEDED(rx_info[1])) {
+		DRM_DEBUG_KMS("Topology Max Size Exceeded\n");
+		return -1;
+	}
+
+	/* Converting and Storing the seq_num_v to local variable as DWORD */
+	reverse_endianness((u8 *)&seq_num_v, HDCP_2_2_SEQ_NUM_LEN,
+			   msgs.recvid_list.seq_num_v);
+
+	if (seq_num_v < hdcp->seq_num_v) {
+		/* Roll over of the seq_num_v from repeater. Reauthenticate. */
+		DRM_DEBUG_KMS("Seq_num_v roll over.\n");
+		return -1;
+	}
+
+	ret = hdcp2_verify_rep_topology_prepare_ack(hdcp, &msgs.recvid_list,
+						    &msgs.rep_ack);
+	if (ret < 0)
+		return ret;
+
+	hdcp->seq_num_v = seq_num_v;
+	ret = shim->write_2_2_msg(intel_dig_port, &msgs.rep_ack,
+				  sizeof(msgs.rep_ack));
+	if (ret < 0)
+		return ret;
+
+	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 = conn_to_dig_port(connector);
@@ -1186,6 +1315,12 @@ static int hdcp2_authenticate_sink(struct intel_connector *connector)
 					       sizeof(stream_type_msg));
 		if (ret < 0)
 			return ret;
+	} else if (hdcp->is_repeater) {
+		ret = hdcp2_authenticate_repeater(connector);
+		if (ret < 0) {
+			DRM_DEBUG_KMS("Repeater Auth Failed. Err: %d\n", ret);
+			return ret;
+		}
 	}
 
 	hdcp->mei_data.streams[0].stream_type = hdcp->content_type;
-- 
2.7.4