Re: [PATCH v9 09/39] drm/i915: Enable and Disable of HDCP2.2

[Daniel Vetter <daniel@ffwll.ch>]

On Thu, Dec 13, 2018 at 09:31:11AM +0530, Ramalingam C wrote:
> Considering that HDCP2.2 is more secure than HDCP1.4, When a setup
> supports HDCP2.2 and HDCP1.4, HDCP2.2 will be enabled.
> 
> When HDCP2.2 enabling fails and HDCP1.4 is supported, HDCP1.4 is
> enabled.
> 
> This change implements a sequence of enabling and disabling of
> HDCP2.2 authentication and HDCP2.2 port encryption.
> 
> v2:
>   Included few optimization suggestions [Chris Wilson]
>   Commit message is updated as per the rebased version.
>   intel_wait_for_register is used instead of wait_for. [Chris Wilson]
> v3:
>   Extra comment added and Style issue fixed [Uma]
> v4:
>   Rebased as part of patch reordering.
>   HDCP2 encryption status is tracked.
>   HW state check is moved into WARN_ON [Daniel]
> v5:
>   Redefined the mei service functions as per comp redesign.
>   Merged patches related to hdcp2.2 enabling and disabling [Sean Paul].
>   Required shim functionality is defined [Sean Paul]
> v6:
>   Return values are handles [Uma]
>   Realigned the code.
>   Check for comp_master is removed.
> v7:
>   HDCP2.2 is attempted only if mei interface is up.
>   Adjust to the new interface
>   Avoid bool usage in struct [Tomas]
> v8:
>   mei_binded status check is removed.
>   %s/hdcp2_in_use/hdcp2_encrypted
> 
> Signed-off-by: Ramalingam C <ramalingam.c@intel.com>

lgtm now.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> ---
>  drivers/gpu/drm/i915/intel_drv.h  |   7 ++
>  drivers/gpu/drm/i915/intel_hdcp.c | 202 +++++++++++++++++++++++++++++++++++---
>  2 files changed, 195 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index decd0346c6a7..6d5361616ca3 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -383,6 +383,10 @@ struct intel_hdcp_shim {
>  
>  	/* HDCP adaptation(DP/HDMI) required on the port */
>  	enum hdcp_wired_protocol protocol;
> +
> +	/* Detects whether Panel is HDCP2.2 capable */
> +	int (*hdcp_2_2_capable)(struct intel_digital_port *intel_dig_port,
> +				bool *capable);
>  };
>  
>  struct intel_hdcp {
> @@ -400,6 +404,9 @@ struct intel_hdcp {
>  	/* Flag indicates whether this connector supports HDCP2.2 or not. */
>  	u8 hdcp2_supported;
>  
> +	/* HDCP2.2 Encryption status */
> +	u8 hdcp2_encrypted;
> +
>  	/*
>  	 * 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/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c
> index 2b7814a6f12b..f0ee448e6546 100644
> --- a/drivers/gpu/drm/i915/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/intel_hdcp.c
> @@ -75,6 +75,23 @@ bool intel_hdcp_capable(struct intel_connector *connector)
>  	return capable;
>  }
>  
> +/* Is HDCP2.2 capable on Platform and Sink */
> +static bool intel_hdcp2_capable(struct intel_connector *connector)
> +{
> +	struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
> +	struct intel_hdcp *hdcp = &connector->hdcp;
> +	bool capable = false;
> +
> +	/* I915 support for HDCP2.2 */
> +	if (!hdcp->hdcp2_supported)
> +		return false;
> +
> +	/* Sink's capability for HDCP2.2 */
> +	hdcp->shim->hdcp_2_2_capable(intel_dig_port, &capable);
> +
> +	return capable;
> +}
> +
>  static inline bool intel_hdcp_in_use(struct intel_connector *connector)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
> @@ -1014,8 +1031,7 @@ int hdcp2_authenticate_port(struct intel_connector *connector)
>  	return ret;
>  }
>  
> -static __attribute__((unused))
> -int hdcp2_close_mei_session(struct intel_connector *connector)
> +static int hdcp2_close_mei_session(struct intel_connector *connector)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>  	struct i915_component_master *comp = dev_priv->comp_master;
> @@ -1024,12 +1040,157 @@ int hdcp2_close_mei_session(struct intel_connector *connector)
>  						  &connector->hdcp.port_data);
>  }
>  
> -static __attribute__((unused))
> -int hdcp2_deauthenticate_port(struct intel_connector *connector)
> +static int hdcp2_deauthenticate_port(struct intel_connector *connector)
>  {
>  	return hdcp2_close_mei_session(connector);
>  }
>  
> +static int hdcp2_authenticate_sink(struct intel_connector *connector)
> +{
> +	DRM_ERROR("Sink authentication is done in subsequent patches\n");
> +
> +	return -EINVAL;
> +}
> +
> +static int hdcp2_enable_encryption(struct intel_connector *connector)
> +{
> +	struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
> +	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
> +	struct intel_hdcp *hdcp = &connector->hdcp;
> +	enum port port = connector->encoder->port;
> +	int ret;
> +
> +	WARN_ON(I915_READ(HDCP2_STATUS_DDI(port)) & LINK_ENCRYPTION_STATUS);
> +
> +	if (hdcp->shim->toggle_signalling) {
> +		ret = hdcp->shim->toggle_signalling(intel_dig_port, true);
> +		if (ret) {
> +			DRM_ERROR("Failed to enable HDCP signalling. %d\n",
> +				  ret);
> +			return ret;
> +		}
> +	}
> +
> +	if (I915_READ(HDCP2_STATUS_DDI(port)) & LINK_AUTH_STATUS) {
> +		/* Link is Authenticated. Now set for Encryption */
> +		I915_WRITE(HDCP2_CTL_DDI(port),
> +			   I915_READ(HDCP2_CTL_DDI(port)) |
> +			   CTL_LINK_ENCRYPTION_REQ);
> +	}
> +
> +	ret = intel_wait_for_register(dev_priv, HDCP2_STATUS_DDI(port),
> +				      LINK_ENCRYPTION_STATUS,
> +				      LINK_ENCRYPTION_STATUS,
> +				      ENCRYPT_STATUS_CHANGE_TIMEOUT_MS);
> +
> +	return ret;
> +}
> +
> +static int hdcp2_disable_encryption(struct intel_connector *connector)
> +{
> +	struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
> +	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
> +	struct intel_hdcp *hdcp = &connector->hdcp;
> +	enum port port = connector->encoder->port;
> +	int ret;
> +
> +	WARN_ON(!(I915_READ(HDCP2_STATUS_DDI(port)) & LINK_ENCRYPTION_STATUS));
> +
> +	I915_WRITE(HDCP2_CTL_DDI(port),
> +		   I915_READ(HDCP2_CTL_DDI(port)) & ~CTL_LINK_ENCRYPTION_REQ);
> +
> +	ret = intel_wait_for_register(dev_priv, HDCP2_STATUS_DDI(port),
> +				      LINK_ENCRYPTION_STATUS, 0x0,
> +				      ENCRYPT_STATUS_CHANGE_TIMEOUT_MS);
> +	if (ret == -ETIMEDOUT)
> +		DRM_DEBUG_KMS("Disable Encryption Timedout");
> +
> +	if (hdcp->shim->toggle_signalling) {
> +		ret = hdcp->shim->toggle_signalling(intel_dig_port, false);
> +		if (ret) {
> +			DRM_ERROR("Failed to disable HDCP signalling. %d\n",
> +				  ret);
> +			return ret;
> +		}
> +	}
> +
> +	return ret;
> +}
> +
> +static int hdcp2_authenticate_and_encrypt(struct intel_connector *connector)
> +{
> +	int ret, i, tries = 3;
> +
> +	for (i = 0; i < tries; i++) {
> +		ret = hdcp2_authenticate_sink(connector);
> +		if (!ret)
> +			break;
> +
> +		/* Clearing the mei hdcp session */
> +		DRM_DEBUG_KMS("HDCP2.2 Auth %d of %d Failed.(%d)\n",
> +			      i + 1, tries, ret);
> +		if (hdcp2_deauthenticate_port(connector) < 0)
> +			DRM_DEBUG_KMS("Port deauth failed.\n");
> +	}
> +
> +	if (i != tries) {
> +		/*
> +		 * Ensuring the required 200mSec min time interval between
> +		 * Session Key Exchange and encryption.
> +		 */
> +		msleep(HDCP_2_2_DELAY_BEFORE_ENCRYPTION_EN);
> +		ret = hdcp2_enable_encryption(connector);
> +		if (ret < 0) {
> +			DRM_DEBUG_KMS("Encryption Enable Failed.(%d)\n", ret);
> +			if (hdcp2_deauthenticate_port(connector) < 0)
> +				DRM_DEBUG_KMS("Port deauth failed.\n");
> +		}
> +	}
> +
> +	return ret;
> +}
> +
> +static int _intel_hdcp2_enable(struct intel_connector *connector)
> +{
> +	struct intel_hdcp *hdcp = &connector->hdcp;
> +	int ret;
> +
> +	DRM_DEBUG_KMS("[%s:%d] HDCP2.2 is being enabled. Type: %d\n",
> +		      connector->base.name, connector->base.base.id,
> +		      hdcp->content_type);
> +
> +	ret = hdcp2_authenticate_and_encrypt(connector);
> +	if (ret) {
> +		DRM_DEBUG_KMS("HDCP2 Type%d  Enabling Failed. (%d)\n",
> +			      hdcp->content_type, ret);
> +		return ret;
> +	}
> +
> +	DRM_DEBUG_KMS("[%s:%d] HDCP2.2 is enabled. Type %d\n",
> +		      connector->base.name, connector->base.base.id,
> +		      hdcp->content_type);
> +
> +	hdcp->hdcp2_encrypted = 1;
> +	return 0;
> +}
> +
> +static int _intel_hdcp2_disable(struct intel_connector *connector)
> +{
> +	int ret;
> +
> +	DRM_DEBUG_KMS("[%s:%d] HDCP2.2 is being Disabled\n",
> +		      connector->base.name, connector->base.base.id);
> +
> +	ret = hdcp2_disable_encryption(connector);
> +
> +	if (hdcp2_deauthenticate_port(connector) < 0)
> +		DRM_DEBUG_KMS("Port deauth failed.\n");
> +
> +	connector->hdcp.hdcp2_encrypted = 0;
> +
> +	return ret;
> +}
> +
>  static inline void _intel_hdcp_check_work(struct intel_connector *connector)
>  {
>  	struct intel_hdcp *hdcp = &connector->hdcp;
> @@ -1145,22 +1306,33 @@ int intel_hdcp_init(struct intel_connector *connector,
>  int intel_hdcp_enable(struct intel_connector *connector)
>  {
>  	struct intel_hdcp *hdcp = &connector->hdcp;
> -	int ret;
> +	int ret = -EINVAL;
>  
>  	if (!hdcp->shim)
>  		return -ENOENT;
>  
>  	mutex_lock(&hdcp->mutex);
>  
> -	ret = _intel_hdcp_enable(connector);
> -	if (ret)
> -		goto out;
> +	/*
> +	 * Considering that HDCP2.2 is more secure than HDCP1.4, If the setup
> +	 * is capable of HDCP2.2, it is preferred to use HDCP2.2.
> +	 */
> +	if (intel_hdcp2_capable(connector))
> +		ret = _intel_hdcp2_enable(connector);
> +
> +	/* When HDCP2.2 fails, HDCP1.4 will be attempted */
> +	if (ret && intel_hdcp_capable(connector)) {
> +		ret = _intel_hdcp_enable(connector);
> +		if (!ret)
> +			schedule_delayed_work(&hdcp->check_work,
> +					      DRM_HDCP_CHECK_PERIOD_MS);
> +	}
> +
> +	if (!ret) {
> +		hdcp->value = DRM_MODE_CONTENT_PROTECTION_ENABLED;
> +		schedule_work(&hdcp->prop_work);
> +	}
>  
> -	hdcp->value = DRM_MODE_CONTENT_PROTECTION_ENABLED;
> -	schedule_work(&hdcp->prop_work);
> -	schedule_delayed_work(&hdcp->check_work,
> -			      DRM_HDCP_CHECK_PERIOD_MS);
> -out:
>  	mutex_unlock(&hdcp->mutex);
>  	return ret;
>  }
> @@ -1177,7 +1349,9 @@ int intel_hdcp_disable(struct intel_connector *connector)
>  
>  	if (hdcp->value != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
>  		hdcp->value = DRM_MODE_CONTENT_PROTECTION_UNDESIRED;
> -		if (hdcp->hdcp_encrypted)
> +		if (hdcp->hdcp2_encrypted)
> +			ret = _intel_hdcp2_disable(connector);
> +		else if (hdcp->hdcp_encrypted)
>  			ret = _intel_hdcp_disable(connector);
>  	}
>  
> -- 
> 2.7.4
> 

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