[PATCH v4 16/16] drm/i915/hdcp: Enable HDCP 2.2 MST support

[Ramalingam C]

On 2020-10-27 at 22:12:08 +0530, Anshuman Gupta wrote:
> Enable HDCP 2.2 over DP MST.
> Authenticate and enable port encryption only once for
> an active HDCP 2.2 session, once port is authenticated
> and encrypted enable encryption for each stream that
> requires encryption on this port.
> 
> Similarly disable the stream encryption for each encrypted
> stream, once all encrypted stream encryption is disabled,
> disable the port HDCP encryption and deauthenticate the port.
> 
> Cc: Ramalingam C <ramalingam.c at intel.com>
> Reviewed-by: Uma Shankar <uma.shankar at intel.com>
> Signed-off-by: Anshuman Gupta <anshuman.gupta at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_hdcp.c | 46 ++++++++++++++++++++++-
>  1 file changed, 44 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
> index 87f7aaf3a319..71fd01bf63a6 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
> @@ -1693,6 +1693,32 @@ static int hdcp2_authenticate_sink(struct intel_connector *connector)
>  	return ret;
>  }
>  
> +static int hdcp2_enable_stream_encryption(struct intel_connector *connector)
> +{
> +	struct intel_digital_port *dig_port = intel_attached_dig_port(connector);
> +	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
> +	struct intel_hdcp *hdcp = &connector->hdcp;
> +	enum transcoder cpu_transcoder = hdcp->cpu_transcoder;
> +	enum port port = dig_port->base.port;
> +	int ret = 0;
> +
> +	if (!(intel_de_read(dev_priv, HDCP2_STATUS(dev_priv, cpu_transcoder, port)) &
> +			    LINK_ENCRYPTION_STATUS)) {
> +		drm_err(&dev_priv->drm, "HDCP 2.2 Link is not encrypted\n");
Provide the connector details in err.
> +		return -EPERM;
> +	}
> +
> +	if (hdcp->shim->stream_2_2_encryption) {
> +		ret = hdcp->shim->stream_2_2_encryption(dig_port, true);
> +		if (ret) {
> +			drm_err(&dev_priv->drm, "Failed to enable HDCP 2.2 stream enc\n");
connector details.
> +			return ret;
> +		}
> +	}
> +
> +	return ret;
> +}
> +
>  static int hdcp2_enable_encryption(struct intel_connector *connector)
>  {
>  	struct intel_digital_port *dig_port = intel_attached_dig_port(connector);
> @@ -1831,7 +1857,7 @@ static int hdcp2_authenticate_and_encrypt(struct intel_connector *connector)
>  			drm_dbg_kms(&i915->drm, "Port deauth failed.\n");
>  	}
>  
> -	if (!ret) {
> +	if (!ret && !dig_port->port_auth) {
>  		/*
>  		 * Ensuring the required 200mSec min time interval between
>  		 * Session Key Exchange and encryption.
> @@ -1846,6 +1872,8 @@ static int hdcp2_authenticate_and_encrypt(struct intel_connector *connector)
>  		}
>  	}
>  
> +	ret = hdcp2_enable_stream_encryption(connector);
> +
>  	return ret;
>  }
>  
> @@ -1891,11 +1919,23 @@ static int _intel_hdcp2_disable(struct intel_connector *connector)
>  	struct intel_digital_port *dig_port = intel_attached_dig_port(connector);
>  	struct drm_i915_private *i915 = to_i915(connector->base.dev);
>  	struct hdcp_port_data *data = &dig_port->port_data;
> +	struct intel_hdcp *hdcp = &connector->hdcp;
>  	int ret;
>  
>  	drm_dbg_kms(&i915->drm, "[%s:%d] HDCP2.2 is being Disabled\n",
>  		    connector->base.name, connector->base.base.id);
>  
> +	if (hdcp->shim->stream_2_2_encryption) {
> +		ret = hdcp->shim->stream_2_2_encryption(dig_port, false);
> +		if (ret) {
> +			drm_err(&i915->drm, "Failed to disable HDCP 2.2 stream enc\n");
connector details in err.

-Ram
> +			return ret;
> +		}
> +	}
> +
> +	if (dig_port->num_hdcp_streams > 0)
> +		return ret;
> +
>  	ret = hdcp2_disable_encryption(connector);
>  
>  	if (hdcp2_deauthenticate_port(connector) < 0)
> @@ -1919,6 +1959,7 @@ static int intel_hdcp2_check_link(struct intel_connector *connector)
>  	int ret = 0;
>  
>  	mutex_lock(&hdcp->mutex);
> +	mutex_lock(&dig_port->hdcp_mutex);
>  	cpu_transcoder = hdcp->cpu_transcoder;
>  
>  	/* hdcp2_check_link is expected only when HDCP2.2 is Enabled */
> @@ -1996,6 +2037,7 @@ static int intel_hdcp2_check_link(struct intel_connector *connector)
>  	}
>  
>  out:
> +	mutex_unlock(&dig_port->hdcp_mutex);
>  	mutex_unlock(&hdcp->mutex);
>  	return ret;
>  }
> @@ -2177,7 +2219,7 @@ int intel_hdcp_init(struct intel_connector *connector,
>  	if (!shim)
>  		return -EINVAL;
>  
> -	if (is_hdcp2_supported(dev_priv) && !connector->mst_port)
> +	if (is_hdcp2_supported(dev_priv))
>  		intel_hdcp2_init(connector, dig_port, shim);
>  
>  	ret =
> -- 
> 2.26.2
>