Re: [PATCH v9 12/39] drm/i915: Implement HDCP2.2 repeater authentication

[Daniel Vetter <daniel@ffwll.ch>]

On Thu, Dec 13, 2018 at 09:31:14AM +0530, Ramalingam C wrote:
> Implements the HDCP2.2 repeaters authentication steps such as verifying
> the downstream topology and sending stream management information.
> 
> v2: Rebased.
> v3:
>   -EINVAL is returned for topology error and rollover scenario.
>   Endianness conversion func from drm_hdcp.h is used [Uma]
> v4:
>   Rebased as part of patches reordering.
>   Defined the mei service functions [Daniel]
> v5:
>   Redefined the mei service functions as per comp redesign.
> v6:
>   %s/uintxx_t/uxx
>   Check for comp_master is removed.
> v7:
>   Adjust to the new mei interface.
>   style issue fixed.
> v8:
>   drm_hdcp.h change is moved into separate patch [Daniel]
> 
> Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_hdcp.c | 123 +++++++++++++++++++++++++++++++++++++-
>  1 file changed, 121 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c
> index f1f0ef294e20..b52da5c3159d 100644
> --- a/drivers/gpu/drm/i915/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/intel_hdcp.c
> @@ -978,7 +978,7 @@ static int hdcp2_prepare_skey(struct intel_connector *connector,
>  	return ret;
>  }
>  
> -static __attribute__((unused)) int
> +static int
>  hdcp2_verify_rep_topology_prepare_ack(struct intel_connector *connector,
>  				      struct hdcp2_rep_send_receiverid_list
>  								*rep_topology,
> @@ -999,7 +999,7 @@ hdcp2_verify_rep_topology_prepare_ack(struct intel_connector *connector,
>  	return ret;
>  }
>  
> -static __attribute__((unused)) int
> +static int
>  hdcp2_verify_mprime(struct intel_connector *connector,
>  		    struct hdcp2_rep_stream_ready *stream_ready)
>  {
> @@ -1182,6 +1182,119 @@ 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;
> +	drm_hdcp2_u32_to_seq_num(msgs.stream_manage.seq_num_m, 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->port_data.seq_num_m = hdcp->seq_num_m;
> +	hdcp->port_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;
> +	u8 *rx_info;
> +	u32 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;

There's a 2s timeout here that we're not checking, but again probably
follow-up patch.

> +
> +	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 */
> +	drm_hdcp2_seq_num_to_u32(&seq_num_v, 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;

Spec talks about type0 vs type1 here, but for now we can ignore that.

> +
> +	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);
> @@ -1223,6 +1336,12 @@ 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;
> +		}
>  	}

Spec for receiver auth is a bit more confusing than usual, but I think
this matches.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
>  
>  	hdcp->port_data.streams[0].stream_type = hdcp->content_type;
> -- 
> 2.7.4
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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