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]
v3:
  rebased.

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1550338640-17470-6-git-send-email-ramalingam.c@intel.com

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index cf709835fb9a9eece3c0761c21c53c34a25b7e22..9f73a4239574ab4bcbae3fcdf0ca2c368c25ab9f 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4780,7 +4780,7 @@ 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 54ea4b5b207341090aca6dbc9e3d19abe547f21f..aaddde44b2702242752add7674b62ec248b67f18 100644 (file)
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -409,6 +409,9 @@ 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;
@@ -2090,12 +2093,12 @@ int intel_hdcp_init(struct intel_connector *connector,
                    const struct intel_hdcp_shim *hdcp_shim);
 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);
 void intel_hdcp_component_init(struct drm_i915_private *dev_priv);
 void intel_hdcp_component_fini(struct drm_i915_private *dev_priv);
 void intel_hdcp_cleanup(struct intel_connector *connector);
+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 d06bef9d1ab25f450615f3c401e8a0f8535f1d2d..66e3850a57a0f1d3e00774e2c4d6e6b824caf0ab 100644 (file)
--- 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 @@ out:
        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)
+{
+       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)
 {
@@ -1281,7 +1295,8 @@ 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);
@@ -1345,3 +1360,21 @@ 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);
+}