Re: [PATCH v6 11/35] drm/i915: Enable and Disable of HDCP2.2

["Shankar, Uma" <uma.shankar@intel.com>]

>-----Original Message-----
>From: C, Ramalingam
>Sent: Saturday, July 14, 2018 8:45 AM
>To: intel-gfx@lists.freedesktop.org; dri-devel@lists.freedesktop.org;
>daniel@ffwll.ch; seanpaul@chromium.org; Winkler, Tomas
><tomas.winkler@intel.com>; Usyskin, Alexander <alexander.usyskin@intel.com>;
>Shankar, Uma <uma.shankar@intel.com>
>Cc: Sharma, Shashank <shashank.sharma@intel.com>; C, Ramalingam
><ramalingam.c@intel.com>
>Subject: [PATCH v6 11/35] drm/i915: Enable and Disable of HDCP2.2
>
>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]
>
>Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
>---
> drivers/gpu/drm/i915/intel_drv.h  |   5 +
> drivers/gpu/drm/i915/intel_hdcp.c | 226
>++++++++++++++++++++++++++++++++++++--
> 2 files changed, 221 insertions(+), 10 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>index 38262792813a..21683702bcdc 100644
>--- a/drivers/gpu/drm/i915/intel_drv.h
>+++ b/drivers/gpu/drm/i915/intel_drv.h
>@@ -380,6 +380,10 @@ 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 {
>@@ -393,6 +397,7 @@ 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 18509c3bae08..4ace64315baa 100644
>--- a/drivers/gpu/drm/i915/intel_hdcp.c
>+++ b/drivers/gpu/drm/i915/intel_hdcp.c
>@@ -17,10 +17,51 @@
> #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 int intel_hdcp2_init(struct intel_connector *connector);
>+static int _intel_hdcp2_enable(struct intel_connector *connector);
>+static int _intel_hdcp2_disable(struct intel_connector *connector);
>+static int intel_hdcp_read_valid_bksv(struct intel_digital_port
>+*intel_dig_port,
>+			       const struct intel_hdcp_shim *shim, u8 *bksv); static
>struct
>+intel_digital_port *conn_to_dig_port(struct intel_connector
>+*connector);
>+
>+/* Is HDCP1.4 capable on Platform and Panel */ static bool

Instead of Panel, call it as sink.

>+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 Panel */ static bool

Same as above.

>+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 panel's hdcp2.2 compliance if platform supports it. */

Here too.

>+	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) @@ -
>791,22 +832,33 @@ 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);
>+	}
>
x>-	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;
> }
>@@ -823,7 +875,10 @@ 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);
>@@ -923,6 +978,157 @@ int intel_hdcp_check_link(struct intel_connector
>*connector)
> 	return ret;
> }
>
>+static int hdcp2_close_mei_session(struct intel_connector *connector) {

The return value is not handled in the call chain. Please check for return value
in the calling functions.

>+	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)
>+		return -EINVAL;
>+
>+	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)

As Described above.

>+{
>+	return hdcp2_close_mei_session(connector);
>+}
>+
>+static int hdcp2_authenticate_sink(struct intel_connector *connector) {
>+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>+
>+	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)
>+		hdcp->shim->toggle_signalling(intel_dig_port, true);

Handle the error returned.

>+
>+	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)
>+		hdcp->shim->toggle_signalling(intel_dig_port, false);
>+
>+	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 */
>+		hdcp2_deauthenticate_port(connector);
>+		DRM_DEBUG_KMS("HDCP2.2 Auth %d of %d Failed.(%d)\n",
>+			      i + 1, tries, ret);
>+	}
>+
>+	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);
>+			hdcp2_deauthenticate_port(connector);
>+		}
>+	}
>+
>+	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);
>+
>+	hdcp2_deauthenticate_port(connector);
>+	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");
>--
>2.7.4

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