[Intel-gfx] [PATCH 1/2] drm/i915/hdcp: Fix 1B-06 HDCP2.2 Comp test

[Anshuman Gupta]

HDCP Repeater initializes seq_num_V to 0 at the beginning of
hdcp Session i.e. after AKE_init received.

HDCP 2.2 Comp specs 1B-06 test verifies that whether DUT
considers failures of authentication if the repeater provides a
non-zero value in seq_num_V in the first,
RepeaterAuth_Send_ReceiverID_List message after first AKE_Init.
Fixing this broken test.

Cc: Ramalingam C <ramalingam.c at intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta at intel.com>
---
 drivers/gpu/drm/i915/display/intel_display_types.h |  3 +++
 drivers/gpu/drm/i915/display/intel_hdcp.c          | 13 +++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 7ae0bc8b80d1..2ae540e986ba 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -360,6 +360,9 @@ struct intel_hdcp {
 	/* HDCP2.2 Encryption status */
 	bool hdcp2_encrypted;
 
+	/* Flag indicate if it is a first ReceiverID_List msg after AKE_Init */
+	bool first_recvid_msg;
+
 	/*
 	 * Content Stream Type defined by content owner. TYPE0(0x0) content can
 	 * flow in the link protected by HDCP2.2 or HDCP1.4, where as TYPE1(0x1)
diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index 4d1a33d13105..3e24a6df503a 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -1251,6 +1251,8 @@ static int hdcp2_authentication_key_exchange(struct intel_connector *connector)
 	size_t size;
 	int ret;
 
+	hdcp->first_recvid_msg = true;
+
 	/* Init for seq_num */
 	hdcp->seq_num_v = 0;
 	hdcp->seq_num_m = 0;
@@ -1462,6 +1464,16 @@ int hdcp2_authenticate_repeater_topology(struct intel_connector *connector)
 	seq_num_v =
 		drm_hdcp_be24_to_cpu((const u8 *)msgs.recvid_list.seq_num_v);
 
+	/*
+	 * HDCP 2.2 Spec HDMI PAGE 19, DP PAGE 20
+	 * HDCP 2.2 Comp 1B-06 test requires to disable encryption if there is
+	 * non zero seq_num_V from recevier.
+	 */
+	if (hdcp->first_recvid_msg && seq_num_v) {
+		drm_dbg_kms(&dev_priv->drm, "Non zero Seq_num_v at beginning of HDCP Session\n");
+		return -EINVAL;
+	}
+
 	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");
@@ -1484,6 +1496,7 @@ int hdcp2_authenticate_repeater_topology(struct intel_connector *connector)
 		return ret;
 
 	hdcp->seq_num_v = seq_num_v;
+	hdcp->first_recvid_msg = false;
 	ret = shim->write_2_2_msg(intel_dig_port, &msgs.rep_ack,
 				  sizeof(msgs.rep_ack));
 	if (ret < 0)
-- 
2.24.0