Re: [PATCH v10 07/40] drm/i915: hdcp1.4 CP_IRQ handling and SW encryption tracking

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.vetter@ffwll.ch" <daniel.vetter@ffwll.ch>,
	"Winkler, Tomas" <tomas.winkler@intel.com>
Subject: Re: [PATCH v10 07/40] drm/i915: hdcp1.4 CP_IRQ handling and SW encryption tracking
Date: Mon, 4 Feb 2019 14:09:48 +0000	[thread overview]
Message-ID: <E7C9878FBA1C6D42A1CA3F62AEB6945F81EEBFC5@BGSMSX104.gar.corp.intel.com> (raw)
In-Reply-To: <1548917996-28081-8-git-send-email-ramalingam.c@intel.com>

>-----Original Message-----
>From: C, Ramalingam
>Sent: Thursday, January 31, 2019 12:29 PM
>To: intel-gfx@lists.freedesktop.org; dri-devel@lists.freedesktop.org;
>daniel.vetter@ffwll.ch; Winkler, Tomas <tomas.winkler@intel.com>; Shankar,
>Uma <uma.shankar@intel.com>
>Cc: C, Ramalingam <ramalingam.c@intel.com>
>Subject: [PATCH v10 07/40] drm/i915: hdcp1.4 CP_IRQ handling and SW
>encryption tracking
>
>"hdcp_encrypted" flag is defined to denote the HDCP1.4 encryption status.
>This SW tracking is used to determine the need for real hdcp1.4 disable and
>hdcp_check_link upon CP_IRQ.
>
>On CP_IRQ we filter the CP_IRQ related to the states like Link failure and
>reauthentication req etc and handle them in hdcp_check_link.
>CP_IRQ corresponding to the authentication msg availability are ignored.
>
>WARN_ON is added for the abrupt stop of HDCP encryption of a port.
>
>v2:
>  bool is used in struct for the cleaner coding. [Daniel]
>  check_link work_fn is scheduled for cp_irq handling [Daniel]
>
>Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
>---
> drivers/gpu/drm/i915/intel_dp.c   |  2 +-
> drivers/gpu/drm/i915/intel_drv.h  |  5 ++-  drivers/gpu/drm/i915/intel_hdcp.c |
>73 ++++++++++++++++++++++++++++-----------
> 3 files changed, 58 insertions(+), 22 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>index 815ee68efa2f..9ce05819fc11 100644
>--- a/drivers/gpu/drm/i915/intel_dp.c
>+++ b/drivers/gpu/drm/i915/intel_dp.c
>@@ -4776,7 +4776,7 @@ static void intel_dp_check_service_irq(struct intel_dp
>*intel_dp)
> 		intel_dp_handle_test_request(intel_dp);
>
> 	if (val & DP_CP_IRQ)
>-		intel_hdcp_check_link(intel_dp->attached_connector);
>+		intel_hdcp_handle_cp_irq(intel_dp->attached_connector);
>
> 	if (val & DP_SINK_SPECIFIC_IRQ)
> 		DRM_DEBUG_DRIVER("Sink specific irq unhandled\n"); diff --git
>a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>index 63e009286d5f..13a41e8cf4ff 100644
>--- a/drivers/gpu/drm/i915/intel_drv.h
>+++ b/drivers/gpu/drm/i915/intel_drv.h
>@@ -399,6 +399,9 @@ struct intel_hdcp {
> 	struct delayed_work check_work;
> 	struct work_struct prop_work;
>
>+	/* HDCP1.4 Encryption status */
>+	bool hdcp_encrypted;
>+
> 	/* HDCP2.2 related definitions */
> 	/* Flag indicates whether this connector supports HDCP2.2 or not. */
> 	bool hdcp2_supported;
>@@ -2073,10 +2076,10 @@ int intel_hdcp_init(struct intel_connector
>*connector,
> 		    bool hdcp2_supported);
> int intel_hdcp_enable(struct intel_connector *connector);  int
>intel_hdcp_disable(struct intel_connector *connector); -int
>intel_hdcp_check_link(struct intel_connector *connector);  bool
>is_hdcp_supported(struct drm_i915_private *dev_priv, enum port port);  bool
>intel_hdcp_capable(struct intel_connector *connector);  bool
>is_hdcp2_supported(struct drm_i915_private *dev_priv);
>+void intel_hdcp_handle_cp_irq(struct intel_connector *connector);
>
> /* intel_psr.c */
> #define CAN_PSR(dev_priv) (HAS_PSR(dev_priv) && dev_priv->psr.sink_support)
>diff --git a/drivers/gpu/drm/i915/intel_hdcp.c
>b/drivers/gpu/drm/i915/intel_hdcp.c
>index e0bb5f32ba90..c1b057f1501b 100644
>--- a/drivers/gpu/drm/i915/intel_hdcp.c
>+++ b/drivers/gpu/drm/i915/intel_hdcp.c
>@@ -74,6 +74,16 @@ bool intel_hdcp_capable(struct intel_connector
>*connector)
> 	return capable;
> }
>
>+static inline bool intel_hdcp_in_use(struct intel_connector *connector)
>+{
>+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>+	enum port port = connector->encoder->port;
>+	u32 reg;
>+
>+	reg = I915_READ(PORT_HDCP_STATUS(port));
>+	return reg & HDCP_STATUS_ENC;
>+}
>+
> static int intel_hdcp_poll_ksv_fifo(struct intel_digital_port *intel_dig_port,
> 				    const struct intel_hdcp_shim *shim)  { @@ -
>668,6 +678,7 @@ static int _intel_hdcp_disable(struct intel_connector
>*connector)
> 	DRM_DEBUG_KMS("[%s:%d] HDCP is being disabled...\n",
> 		      connector->base.name, connector->base.base.id);
>
>+	hdcp->hdcp_encrypted = false;
> 	I915_WRITE(PORT_HDCP_CONF(port), 0);
> 	if (intel_wait_for_register(dev_priv, PORT_HDCP_STATUS(port), ~0, 0,
> 				    ENCRYPT_STATUS_CHANGE_TIMEOUT_MS)) {
>@@ -713,8 +724,10 @@ static int _intel_hdcp_enable(struct intel_connector
>*connector)
> 	/* Incase of authentication failures, HDCP spec expects reauth. */
> 	for (i = 0; i < tries; i++) {
> 		ret = intel_hdcp_auth(conn_to_dig_port(connector), hdcp-
>>shim);
>-		if (!ret)
>+		if (!ret) {
>+			hdcp->hdcp_encrypted = true;
> 			return 0;
>+		}
>
> 		DRM_DEBUG_KMS("HDCP Auth failure (%d)\n", ret);
>
>@@ -741,16 +754,17 @@ int intel_hdcp_check_link(struct intel_connector
>*connector)
> 	enum port port = intel_dig_port->base.port;
> 	int ret = 0;
>
>-	if (!hdcp->shim)
>-		return -ENOENT;
>-
> 	mutex_lock(&hdcp->mutex);
>
>-	if (hdcp->value == DRM_MODE_CONTENT_PROTECTION_UNDESIRED)
>+	/* Check_link valid only when HDCP1.4 is enabled */
>+	if (hdcp->value != DRM_MODE_CONTENT_PROTECTION_ENABLED ||
>+	    !hdcp->hdcp_encrypted) {
>+		ret = -EINVAL;
> 		goto out;
>+	}
>
>-	if (!(I915_READ(PORT_HDCP_STATUS(port)) & HDCP_STATUS_ENC)) {
>-		DRM_ERROR("%s:%d HDCP check failed: link is not
>encrypted,%x\n",
>+	if (WARN_ON(!intel_hdcp_in_use(connector))) {
>+		DRM_ERROR("%s:%d HDCP link stopped encryption,%x\n",
> 			  connector->base.name, connector->base.base.id,
> 			  I915_READ(PORT_HDCP_STATUS(port)));
> 		ret = -ENXIO;
>@@ -791,18 +805,6 @@ int intel_hdcp_check_link(struct intel_connector
>*connector)
> 	return ret;
> }
>
>-static void intel_hdcp_check_work(struct work_struct *work) -{
>-	struct intel_hdcp *hdcp = container_of(to_delayed_work(work),
>-					       struct intel_hdcp,
>-					       check_work);
>-	struct intel_connector *connector = intel_hdcp_to_connector(hdcp);
>-
>-	if (!intel_hdcp_check_link(connector))
>-		schedule_delayed_work(&hdcp->check_work,
>-				      DRM_HDCP_CHECK_PERIOD_MS);
>-}
>-
> static void intel_hdcp_prop_work(struct work_struct *work)  {
> 	struct intel_hdcp *hdcp = container_of(work, struct intel_hdcp, @@ -
>1120,6 +1122,18 @@ int hdcp2_deauthenticate_port(struct intel_connector
>*connector)
> 	return hdcp2_close_mei_session(connector);
> }
>
>+static void intel_hdcp_check_work(struct work_struct *work) {

Why this code movement for check_work. If not intentional no need for this change.
With proper justification or this fixed.

Reviewed-by: Uma Shankar <uma.shankar@intel.com>

>+	struct intel_hdcp *hdcp = container_of(to_delayed_work(work),
>+					       struct intel_hdcp,
>+					       check_work);
>+	struct intel_connector *connector = intel_hdcp_to_connector(hdcp);
>+
>+	if (!intel_hdcp_check_link(connector))
>+		schedule_delayed_work(&hdcp->check_work,
>+				      DRM_HDCP_CHECK_PERIOD_MS);
>+}
>+
> static int i915_hdcp_component_bind(struct device *i915_kdev,
> 				    struct device *mei_kdev, void *data)  { @@ -
>1288,7 +1302,8 @@ int intel_hdcp_disable(struct intel_connector *connector)
>
> 	if (hdcp->value != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
> 		hdcp->value =
>DRM_MODE_CONTENT_PROTECTION_UNDESIRED;
>-		ret = _intel_hdcp_disable(connector);
>+		if (hdcp->hdcp_encrypted)
>+			ret = _intel_hdcp_disable(connector);
> 	}
>
> 	mutex_unlock(&hdcp->mutex);
>@@ -1328,3 +1343,21 @@ void intel_hdcp_atomic_check(struct drm_connector
>*connector,
> 						   new_state->crtc);
> 	crtc_state->mode_changed = true;
> }
>+
>+/* Handles the CP_IRQ raised from the DP HDCP sink */ void
>+intel_hdcp_handle_cp_irq(struct intel_connector *connector) {
>+	struct intel_hdcp *hdcp = &connector->hdcp;
>+
>+	if (!hdcp->shim)
>+		return;
>+
>+	/*
>+	 * CP_IRQ could be triggered due to 1. HDCP2.2 auth msgs availability,
>+	 * 2. link failure and 3. repeater reauth request. At present we dont
>+	 * handle the CP_IRQ for the HDCP2.2 auth msg availability for read.
>+	 * To handle other two causes for CP_IRQ we have the work_fn which is
>+	 * scheduled here.
>+	 */
>+	schedule_delayed_work(&hdcp->check_work, 0); }
>--
>2.7.4

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