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:
  No changes.
v4:
  Extra comment added and Style issue fixed [Uma]
v5:
  Rebased as part of patch reordering.
  HDCP2 encryption status is tracked.
  HW state check is moved into WARN_ON [Daniel]
v6:
  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]
v7:
  Return values are handles [Uma]
  Realigned the code.
  Check for comp_master is removed.

Signed-off-by: Ramalingam C <ramalinga...@intel.com>
---
 drivers/gpu/drm/i915/intel_drv.h  |   5 +
 drivers/gpu/drm/i915/intel_hdcp.c | 234 ++++++++++++++++++++++++++++++++++++--
 2 files changed, 229 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index b18caaa96b26..5838cc7eb048 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 {
 
        /* Detects the HDCP protocol(DP/HDMI) required on the port */
        enum hdcp_protocol (*hdcp_protocol)(void);
+
+       /* Detects whether Panel is HDCP2.2 capable */
+       int (*hdcp_2_2_capable)(struct intel_digital_port *intel_dig_port,
+                               bool *capable);
 };
 
 struct intel_hdcp {
@@ -396,6 +400,7 @@ struct intel_hdcp {
        /* HDCP2.2 related definitions */
        /* Flag indicates whether this connector supports HDCP2.2 or not. */
        bool hdcp2_supported;
+       bool hdcp2_in_use;
 
        /*
         * Content Stream Type defined by content owner. TYPE0(0x0) content can
diff --git a/drivers/gpu/drm/i915/intel_hdcp.c 
b/drivers/gpu/drm/i915/intel_hdcp.c
index 171733919430..cec96ce75a26 100644
--- a/drivers/gpu/drm/i915/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/intel_hdcp.c
@@ -17,10 +17,14 @@
 #include "i915_reg.h"
 
 #define KEY_LOAD_TRIES 5
+#define TIME_FOR_ENCRYPT_STATUS_CHANGE 32
 #define GET_MEI_DDI_INDEX(port)                (((port) == PORT_A) ? DDI_A : \
                                         (enum hdcp_physical_port)(port))
 
 static
+struct intel_digital_port *conn_to_dig_port(struct intel_connector *connector);
+
+static
 bool intel_hdcp_is_ksv_valid(u8 *ksv)
 {
        int i, ones = 0;
@@ -55,6 +59,39 @@ int intel_hdcp_read_valid_bksv(struct intel_digital_port 
*intel_dig_port,
        return 0;
 }
 
+/* Is HDCP1.4 capable on Platform and Sink */
+static bool intel_hdcp_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;
+       u8 bksv[5];
+
+       if (hdcp->shim->hdcp_capable) {
+               hdcp->shim->hdcp_capable(intel_dig_port, &capable);
+       } else {
+               if (!intel_hdcp_read_valid_bksv(intel_dig_port,
+                                               hdcp->shim, bksv))
+                       capable = true;
+       }
+
+       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;
+
+       /* Check the sink's hdcp2.2 compliance if platform supports it. */
+       if (hdcp->hdcp2_supported)
+               hdcp->shim->hdcp_2_2_capable(intel_dig_port, &capable);
+
+       return capable;
+}
+
 static int intel_hdcp_poll_ksv_fifo(struct intel_digital_port *intel_dig_port,
                                    const struct intel_hdcp_shim *shim)
 {
@@ -820,6 +857,169 @@ bool is_hdcp_supported(struct drm_i915_private *dev_priv, 
enum port port)
                !IS_CHERRYVIEW(dev_priv) && port < PORT_E);
 }
 
+static int hdcp2_close_mei_session(struct intel_connector *connector)
+{
+       struct mei_hdcp_data *data = &connector->hdcp.mei_data;
+       struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+       struct i915_component_master *comp = dev_priv->comp_master;
+
+       if (!comp->hdcp_ops || !comp->mei_cldev || data->port == INVALID_PORT)
+               return -EINVAL;
+
+       return comp->hdcp_ops->close_hdcp_session(comp->mei_cldev, data);
+}
+
+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,
+                                     TIME_FOR_ENCRYPT_STATUS_CHANGE);
+
+       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,
+                                     TIME_FOR_ENCRYPT_STATUS_CHANGE);
+       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_ERROR("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_in_use = true;
+       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_in_use = false;
+
+       return ret;
+}
+
 static int i915_hdcp_component_match(struct device *dev, void *data)
 {
        return !strcmp(dev->driver->name, "mei_hdcp");
@@ -908,22 +1108,33 @@ 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;
 }
@@ -940,7 +1151,10 @@ 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->hdcp2_in_use)
+                       ret = _intel_hdcp2_disable(connector);
+               else
+                       ret = _intel_hdcp_disable(connector);
        }
 
        mutex_unlock(&hdcp->mutex);
-- 
2.7.4

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