[PATCH v8 09/35] drm/i915: Implement HDCP2.2 link integrity check

From: Ramalingam C <ramalingam.c@intel.com>
To: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	daniel.vetter@ffwll.ch, tomas.winkler@intel.com
Cc: uma.shankar@intel.com
Subject: [PATCH v8 09/35] drm/i915: Implement HDCP2.2 link integrity check
Date: Tue, 27 Nov 2018 16:13:07 +0530	[thread overview]
Message-ID: <1543315413-24302-10-git-send-email-ramalingam.c@intel.com> (raw)
In-Reply-To: <1543315413-24302-1-git-send-email-ramalingam.c@intel.com>

Implements the link integrity check once in 500mSec.

Once encryption is enabled, an ongoing Link Integrity Check is
performed by the HDCP Receiver to check that cipher synchronization
is maintained between the HDCP Transmitter and the HDCP Receiver.

On the detection of synchronization lost, the HDCP Receiver must assert
the corresponding bits of the RxStatus register. The Transmitter polls
the RxStatus register and it may initiate re-authentication.

v2:
  Rebased.
v3:
  No Changes.
v4:
  enum check_link_response is used check the link status [Uma]
v5:
  Rebased as part of patch reordering.
v6:
  Required members of intel_hdcp is defined [Sean Paul]
v7:
  hdcp2_check_link is cancelled at required places.
v8:
  Rebased for the component i/f changes.
  Errors due to the sinks are reported as DEBUG logs.

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 11 +++--
 drivers/gpu/drm/i915/intel_drv.h     |  5 +++
 drivers/gpu/drm/i915/intel_hdcp.c    | 83 +++++++++++++++++++++++++++++++++++-
 include/drm/drm_hdcp.h               |  8 ++++
 4 files changed, 103 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index e9f4e22b2a4e..fc63babce165 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -15833,15 +15833,20 @@ static void intel_hpd_poll_fini(struct drm_device *dev)
 {
 	struct intel_connector *connector;
 	struct drm_connector_list_iter conn_iter;
+	struct intel_hdcp *hdcp;
 
 	/* Kill all the work that may have been queued by hpd. */
 	drm_connector_list_iter_begin(dev, &conn_iter);
 	for_each_intel_connector_iter(connector, &conn_iter) {
+		hdcp = &connector->hdcp;
+
 		if (connector->modeset_retry_work.func)
 			cancel_work_sync(&connector->modeset_retry_work);
-		if (connector->hdcp.shim) {
-			cancel_delayed_work_sync(&connector->hdcp.check_work);
-			cancel_work_sync(&connector->hdcp.prop_work);
+		if (hdcp->shim) {
+			cancel_delayed_work_sync(&hdcp->check_work);
+			cancel_work_sync(&hdcp->prop_work);
+			if (hdcp->hdcp2_supported)
+				cancel_delayed_work_sync(&hdcp->hdcp2_check_work);
 		}
 	}
 	drm_connector_list_iter_end(&conn_iter);
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 24d258488efe..e6e32bf52568 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -403,6 +403,9 @@ struct intel_hdcp_shim {
 	 */
 	int (*config_stream_type)(struct intel_digital_port *intel_dig_port,
 				  void *buf, size_t size);
+
+	/* HDCP2.2 Link Integrity Check */
+	int (*check_2_2_link)(struct intel_digital_port *intel_dig_port);
 };
 
 struct intel_hdcp {
@@ -445,6 +448,8 @@ struct intel_hdcp {
 	 * over re-Auth has to be triggered.
 	 */
 	u32 seq_num_m;
+
+	struct delayed_work hdcp2_check_work;
 };
 
 struct intel_connector {
diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c
index 679f3c164582..98b112395a5a 100644
--- a/drivers/gpu/drm/i915/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/intel_hdcp.c
@@ -1626,6 +1626,81 @@ static int _intel_hdcp2_disable(struct intel_connector *connector)
 	return ret;
 }
 
+/* Implements the Link Integrity Check for HDCP2.2 */
+static int intel_hdcp2_check_link(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 = 0;
+
+	if (!hdcp->shim)
+		return -ENOENT;
+
+	mutex_lock(&hdcp->mutex);
+
+	if (hdcp->value == DRM_MODE_CONTENT_PROTECTION_UNDESIRED)
+		goto out;
+
+	if (!(I915_READ(HDCP2_STATUS_DDI(port)) & LINK_ENCRYPTION_STATUS)) {
+		DRM_ERROR("HDCP2.2 check failed: link is not encrypted, %x\n",
+			  I915_READ(HDCP2_STATUS_DDI(port)));
+		ret = -ENXIO;
+		hdcp->value = DRM_MODE_CONTENT_PROTECTION_DESIRED;
+		schedule_work(&hdcp->prop_work);
+		goto out;
+	}
+
+	ret = hdcp->shim->check_2_2_link(intel_dig_port);
+	if (ret == DRM_HDCP_LINK_PROTECTED) {
+		if (hdcp->value != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
+			hdcp->value = DRM_MODE_CONTENT_PROTECTION_ENABLED;
+			schedule_work(&hdcp->prop_work);
+		}
+		goto out;
+	}
+
+	DRM_DEBUG_KMS("[%s:%d] HDCP2.2 link failed, retrying auth\n",
+		      connector->base.name, connector->base.base.id);
+
+	ret = _intel_hdcp2_disable(connector);
+	if (ret) {
+		DRM_ERROR("[%s:%d] Failed to disable hdcp2.2 (%d)\n",
+			  connector->base.name, connector->base.base.id, ret);
+		hdcp->value = DRM_MODE_CONTENT_PROTECTION_DESIRED;
+		schedule_work(&hdcp->prop_work);
+		goto out;
+	}
+
+	ret = _intel_hdcp2_enable(connector);
+	if (ret) {
+		DRM_DEBUG_KMS("[%s:%d] Failed to enable hdcp2.2 (%d)\n",
+			      connector->base.name, connector->base.base.id,
+			      ret);
+		hdcp->value = DRM_MODE_CONTENT_PROTECTION_DESIRED;
+		schedule_work(&hdcp->prop_work);
+		goto out;
+	}
+
+out:
+	mutex_unlock(&hdcp->mutex);
+	return ret;
+}
+
+static void intel_hdcp2_check_work(struct work_struct *work)
+{
+	struct intel_hdcp *hdcp = container_of(to_delayed_work(work),
+					       struct intel_hdcp,
+					       hdcp2_check_work);
+	struct intel_connector *connector = intel_hdcp_to_connector(hdcp);
+
+	if (!intel_hdcp2_check_link(connector))
+		schedule_delayed_work(&hdcp->hdcp2_check_work,
+				      DRM_HDCP2_CHECK_PERIOD_MS);
+}
+
 static int i915_hdcp_component_master_bind(struct device *dev)
 {
 	struct drm_i915_private *dev_priv = kdev_to_i915(dev);
@@ -1762,6 +1837,7 @@ static void intel_hdcp2_init(struct intel_connector *connector)
 		return;
 	}
 
+	INIT_DELAYED_WORK(&hdcp->hdcp2_check_work, intel_hdcp2_check_work);
 	hdcp->hdcp2_supported = 1;
 }
 
@@ -1836,8 +1912,12 @@ int intel_hdcp_enable(struct intel_connector *connector)
 	 * 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))
+	if (intel_hdcp2_capable(connector)) {
 		ret = _intel_hdcp2_enable(connector);
+		if (!ret)
+			schedule_delayed_work(&hdcp->hdcp2_check_work,
+					      DRM_HDCP2_CHECK_PERIOD_MS);
+	}
 
 	/* When HDCP2.2 fails, HDCP1.4 will be attempted */
 	if (ret && intel_hdcp_capable(connector)) {
@@ -1876,6 +1956,7 @@ int intel_hdcp_disable(struct intel_connector *connector)
 
 	mutex_unlock(&hdcp->mutex);
 	cancel_delayed_work_sync(&hdcp->check_work);
+	cancel_delayed_work_sync(&hdcp->hdcp2_check_work);
 	return ret;
 }
 
diff --git a/include/drm/drm_hdcp.h b/include/drm/drm_hdcp.h
index 3e45a7618ab3..be07a2b56d23 100644
--- a/include/drm/drm_hdcp.h
+++ b/include/drm/drm_hdcp.h
@@ -11,6 +11,14 @@
 
 /* Period of hdcp checks (to ensure we're still authenticated) */
 #define DRM_HDCP_CHECK_PERIOD_MS		(128 * 16)
+#define DRM_HDCP2_CHECK_PERIOD_MS		500
+
+enum check_link_response {
+	DRM_HDCP_LINK_PROTECTED	= 0,
+	DRM_HDCP_TOPOLOGY_CHANGE,
+	DRM_HDCP_LINK_INTEGRITY_FAILURE,
+	DRM_HDCP_REAUTH_REQUEST
+};
 
 /* Shared lengths/masks between HDMI/DVI/DisplayPort */
 #define DRM_HDCP_AN_LEN				8
-- 
2.7.4

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