Re: [PATCH v6 13/35] drm/i915: Implement HDCP2.2 repeater authentication

From: "Shankar, Uma" <uma.shankar@intel.com>
To: "C, Ramalingam" <ramalingam.c@intel.com>,
	"intel-gfx@lists.freedesktop.org"
	<intel-gfx@lists.freedesktop.org>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>,
	"daniel@ffwll.ch" <daniel@ffwll.ch>,
	"seanpaul@chromium.org" <seanpaul@chromium.org>,
	"Winkler, Tomas" <tomas.winkler@intel.com>,
	"Usyskin, Alexander" <alexander.usyskin@intel.com>
Subject: Re: [PATCH v6 13/35] drm/i915: Implement HDCP2.2 repeater authentication
Date: Wed, 1 Aug 2018 10:30:00 +0000	[thread overview]
Message-ID: <E7C9878FBA1C6D42A1CA3F62AEB6945F7F37CB42@BGSMSX104.gar.corp.intel.com> (raw)
In-Reply-To: <1531538117-1606-14-git-send-email-ramalingam.c@intel.com>

>-----Original Message-----
>From: C, Ramalingam
>Sent: Saturday, July 14, 2018 8:45 AM
>To: intel-gfx@lists.freedesktop.org; dri-devel@lists.freedesktop.org;
>daniel@ffwll.ch; seanpaul@chromium.org; Winkler, Tomas
><tomas.winkler@intel.com>; Usyskin, Alexander <alexander.usyskin@intel.com>;
>Shankar, Uma <uma.shankar@intel.com>
>Cc: Sharma, Shashank <shashank.sharma@intel.com>; C, Ramalingam
><ramalingam.c@intel.com>
>Subject: [PATCH v6 13/35] drm/i915: Implement HDCP2.2 repeater authentication
>
>Implements the HDCP2.2 repeaters authentication steps such as verifying the
>downstream topology and sending stream management information.
>
>v2:
>  Rebased.
>v3:
>  No Changes.
>v4:
>  -EINVAL is returned for topology error and rollover scenario.
>  Endianness conversion func from drm_hdcp.h is used [Uma]
>v5:
>  Rebased as part of patches reordering.
>  Defined the mei service functions [Daniel]
>v6:
>  Redefined the mei service functions as per comp redesign.
>
>Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
>---
> drivers/gpu/drm/i915/intel_hdcp.c | 171
>++++++++++++++++++++++++++++++++++++++
> include/drm/drm_hdcp.h            |  15 ++++
> 2 files changed, 186 insertions(+)
>
>diff --git a/drivers/gpu/drm/i915/intel_hdcp.c
>b/drivers/gpu/drm/i915/intel_hdcp.c
>index ee1e06bac175..a08d80c710d7 100644
>--- a/drivers/gpu/drm/i915/intel_hdcp.c
>+++ b/drivers/gpu/drm/i915/intel_hdcp.c
>@@ -1144,6 +1144,56 @@ static int hdcp2_prepare_skey(struct intel_connector
>*connector,
> 	return ret;
> }
>
>+static int
>+hdcp2_verify_rep_topology_prepare_ack(
>+			struct intel_connector *connector,
>+			struct hdcp2_rep_send_receiverid_list *rep_topology,
>+			struct hdcp2_rep_send_ack *rep_send_ack) {
>+	struct mei_hdcp_data *data = &connector->hdcp.mei_data;
>+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>+	struct i915_component_master *comp = dev_priv->comp_master;
>+	int ret;
>+
>+	if (!comp)
>+		return -EINVAL;
>+
>+	if (!comp->hdcp_ops || !comp->mei_cldev || data->port ==
>INVALID_PORT)
>+		return -EINVAL;
>+
>+	ret = comp->hdcp_ops->repeater_check_flow_prepare_ack(comp-
>>mei_cldev,
>+							      data,
>+							      rep_topology,
>+							      rep_send_ack);

Same as mentioned in earlier patch in the series.
Otherwise overall the change looks ok to me.

>+	if (ret < 0)
>+		comp->hdcp_ops->close_hdcp_session(comp->mei_cldev, data);
>+
>+	return ret;
>+}
>+
>+static int
>+hdcp2_verify_mprime(struct intel_connector *connector,
>+		    struct hdcp2_rep_stream_ready *stream_ready) {
>+	struct mei_hdcp_data *data = &connector->hdcp.mei_data;
>+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>+	struct i915_component_master *comp = dev_priv->comp_master;
>+	int ret;
>+
>+	if (!comp)
>+		return -EINVAL;
>+
>+	if (!comp->hdcp_ops || !comp->mei_cldev || data->port ==
>INVALID_PORT)
>+		return -EINVAL;
>+
>+	ret = comp->hdcp_ops->verify_mprime(comp->mei_cldev, data,
>+					    stream_ready);
>+	if (ret < 0)
>+		comp->hdcp_ops->close_hdcp_session(comp->mei_cldev, data);
>+
>+	return ret;
>+}
>+
> static int hdcp2_authenticate_port(struct intel_connector *connector)  {
> 	struct mei_hdcp_data *data = &connector->hdcp.mei_data; @@ -1319,6
>+1369,121 @@ static int hdcp2_session_key_exchange(struct intel_connector
>*connector)
> 	return 0;
> }
>
>+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->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));

How the timeout of 100ms is ensured here.

>+	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(connector, &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->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 -EINVAL;
>+	}
>+
>+	/* 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 -EINVAL;
>+	}
>+
>+	ret = hdcp2_verify_rep_topology_prepare_ack(connector,
>+						    &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);
>@@ -1360,6 +1525,12 @@ 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; diff --git
>a/include/drm/drm_hdcp.h b/include/drm/drm_hdcp.h index
>2b4cfb0b7324..c01cdb1d848d 100644
>--- a/include/drm/drm_hdcp.h
>+++ b/include/drm/drm_hdcp.h
>@@ -252,4 +252,19 @@ struct hdcp2_dp_errata_stream_type {
> #define HDCP_2_2_HDMI_RXSTATUS_READY(x)		((x) & BIT(2))
> #define HDCP_2_2_HDMI_RXSTATUS_REAUTH_REQ(x)	((x) & BIT(3))
>
>+/*
>+ * Library functions for endianness are aligned for 16/32/64 bits.
>+ * But hdcp sequence numbers are 24bits. So for their Byte swapping,
>+ * a conversion function is developed.
>+ */
>+static inline void reverse_endianness(u8 *dest, size_t sz, u8 *src) {
>+	u32 index;
>+
>+	if (!sz || sz > sizeof(u32))
>+		return;
>+	for (index = 0; index < sz; index++)
>+		dest[sz - index - 1] = src[index];
>+}
>+
> #endif
>--
>2.7.4

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