[PATCH v10 08/40] drm/i915: Enable and Disable of HDCP2.2

Ramalingam C
2019-01-31T06:59:24Z

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:
Extra comment added and Style issue fixed [Uma]
v4:
Rebased as part of patch reordering.
HDCP2 encryption status is tracked.
HW state check is moved into WARN_ON [Daniel]
v5:
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]
v6:
Return values are handles [Uma]
Realigned the code.
Check for comp_master is removed.
v7:
HDCP2.2 is attempted only if mei interface is up.
Adjust to the new interface
Avoid bool usage in struct [Tomas]
v8:
mei_binded status check is removed.
%s/hdcp2_in_use/hdcp2_encrypted
v9:
bool is used in struct intel_hdcp. [Daniel]

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
drivers/gpu/drm/i915/intel_drv.h | 7 ++
drivers/gpu/drm/i915/intel_hdcp.c | 202 +++++++++++++++++++++++++++++++++++---
2 files changed, 195 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 13a41e8cf4ff..31c7a4577ca9 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -389,6 +389,10 @@ struct intel_hdcp_shim {

/* HDCP adaptation(DP/HDMI) required on the port */
enum hdcp_wired_protocol protocol;
+
+ /* Detects whether Panel is HDCP2.2 capable */
+ int (*hdcp_2_2_capable)(struct intel_digital_port *intel_dig_port,
+ bool *capable);
};

struct intel_hdcp {
@@ -406,6 +410,9 @@ struct intel_hdcp {
/* Flag indicates whether this connector supports HDCP2.2 or not. */
bool hdcp2_supported;

+ /* HDCP2.2 Encryption status */
+ bool hdcp2_encrypted;
+
/*
* Content Stream Type defined by content owner. TYPE0(0x0) content can
* flow in the link protected by HDCP2.2 or HDCP1.4, where as TYPE1(0x1)
diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c
index c1b057f1501b..fbf8b7893bfa 100644
--- a/drivers/gpu/drm/i915/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/intel_hdcp.c
@@ -74,6 +74,23 @@ bool intel_hdcp_capable(struct intel_connector *connector)
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;
+
+ /* I915 support for HDCP2.2 */
+ if (!hdcp->hdcp2_supported)
+ return false;
+
+ /* Sink's capability for HDCP2.2 */
+ hdcp->shim->hdcp_2_2_capable(intel_dig_port, &capable);
+
+ return capable;
+}
+
static inline bool intel_hdcp_in_use(struct intel_connector *connector)
{
struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
@@ -1094,8 +1111,7 @@ int hdcp2_authenticate_port(struct intel_connector *connector)
return ret;
}

-static __attribute__((unused))
-int hdcp2_close_mei_session(struct intel_connector *connector)
+static int hdcp2_close_mei_session(struct intel_connector *connector)
{
struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
struct i915_hdcp_comp_master *comp;
@@ -1116,12 +1132,157 @@ int hdcp2_close_mei_session(struct intel_connector *connector)
return ret;
}

-static __attribute__((unused))
-int hdcp2_deauthenticate_port(struct intel_connector *connector)
+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,
+ ENCRYPT_STATUS_CHANGE_TIMEOUT_MS);
+
+ 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,
+ ENCRYPT_STATUS_CHANGE_TIMEOUT_MS);
+ 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_DEBUG_KMS("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_encrypted = 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_encrypted = false;
+
+ return ret;
+}
+
static void intel_hdcp_check_work(struct work_struct *work)
{
struct intel_hdcp *hdcp = container_of(to_delayed_work(work),
@@ -1270,22 +1431,33 @@ 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;
}
@@ -1302,7 +1474,9 @@ int intel_hdcp_disable(struct intel_connector *connector)

if (hdcp->value != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
hdcp->value = DRM_MODE_CONTENT_PROTECTION_UNDESIRED;
- if (hdcp->hdcp_encrypted)
+ if (hdcp->hdcp2_encrypted)
+ ret = _intel_hdcp2_disable(connector);
+ else if (hdcp->hdcp_encrypted)
ret = _intel_hdcp_disable(connector);
}

--
2.7.4

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