Re: [PATCH v10 13/40] drm/i915: Implement HDCP2.2 link integrity check

Shankar, Uma
2019-02-04T14:28:18Z

>-----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 13/40] drm/i915: Implement HDCP2.2 link integrity check
>
>Implements the link integrity check once in 500mSec.
>
>Once encryption is enabled, an ongoing Link Integrity Check is performed by the
>HDCP Receiver to check that cipher synchronization is maintained between the
>HDCP Transmitter and the HDCP Receiver.
>
>On the detection of synchronization lost, the HDCP Receiver must assert the
>corresponding bits of the RxStatus register. The Transmitter polls the RxStatus
>register and it may initiate re-authentication.
>
>v2:
> Rebased.
>v3:
> enum check_link_response is used check the link status [Uma]
>v4:
> Rebased as part of patch reordering.
>v5:
> Required members of intel_hdcp is defined [Sean Paul]
>v6:
> hdcp2_check_link is cancelled at required places.
>v7:
> Rebased for the component i/f changes.
> Errors due to the sinks are reported as DEBUG logs.
>v8:
> hdcp_check_work is used for both hdcp1 and hdcp2 check_link [Daniel]
> hdcp2.2 encryption status check is put under WARN_ON [Daniel]
> drm_hdcp.h changes are moved into separate patch [Daniel]
>v9:
> enum check_link_status is defined at intel_drv.h [Daniel]
>
>Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
>Reviewed-by: Uma Shankar <uma.shankar@intel.com>

The latest version also looks ok. You can keep my RB.

>---
> drivers/gpu/drm/i915/intel_drv.h | 10 +++++ drivers/gpu/drm/i915/intel_hdcp.c
>| 88 ++++++++++++++++++++++++++++++++++++---
> 2 files changed, 93 insertions(+), 5 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>index e6792304520a..747fe7361287 100644
>--- a/drivers/gpu/drm/i915/intel_drv.h
>+++ b/drivers/gpu/drm/i915/intel_drv.h
>@@ -314,6 +314,13 @@ struct intel_panel {
>
> struct intel_digital_port;
>
>+enum check_link_response {
>+ HDCP_LINK_PROTECTED = 0,
>+ HDCP_TOPOLOGY_CHANGE,
>+ HDCP_LINK_INTEGRITY_FAILURE,
>+ HDCP_REAUTH_REQUEST
>+};
>+
> /*
> * This structure serves as a translation layer between the generic HDCP code
> * and the bus-specific code. What that means is that HDCP over HDMI differs
>@@ -409,6 +416,9 @@ struct intel_hdcp_shim {
> */
> int (*config_stream_type)(struct intel_digital_port *intel_dig_port,
> bool is_repeater, u8 type);
>+
>+ /* HDCP2.2 Link Integrity Check */
>+ int (*check_2_2_link)(struct intel_digital_port *intel_dig_port);
> };
>
> struct intel_hdcp {
>diff --git a/drivers/gpu/drm/i915/intel_hdcp.c
>b/drivers/gpu/drm/i915/intel_hdcp.c
>index 3b8d3a4b5e6e..3feff921a547 100644
>--- a/drivers/gpu/drm/i915/intel_hdcp.c
>+++ b/drivers/gpu/drm/i915/intel_hdcp.c
>@@ -102,6 +102,16 @@ static inline bool intel_hdcp_in_use(struct
>intel_connector *connector)
> return reg & HDCP_STATUS_ENC;
> }
>
>+static inline bool intel_hdcp2_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(HDCP2_STATUS_DDI(port));
>+ return reg & LINK_ENCRYPTION_STATUS;
>+}
>+
> static int intel_hdcp_poll_ksv_fifo(struct intel_digital_port *intel_dig_port,
> const struct intel_hdcp_shim *shim) { @@ -
>1571,6 +1581,69 @@ static int _intel_hdcp2_disable(struct intel_connector
>*connector)
> return ret;
> }
>
>+/* Implements the Link Integrity Check for HDCP2.2 */ static int
>+intel_hdcp2_check_link(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 = 0;
>+
>+ mutex_lock(&hdcp->mutex);
>+
>+ /* hdcp2_check_link is expected only when HDCP2.2 is Enabled */
>+ if (hdcp->value != DRM_MODE_CONTENT_PROTECTION_ENABLED ||
>+ !hdcp->hdcp2_encrypted) {
>+ ret = -EINVAL;
>+ goto out;
>+ }
>+
>+ if (WARN_ON(!intel_hdcp2_in_use(connector))) {
>+ DRM_ERROR("HDCP2.2 link stopped the encryption, %x\n",
>+ I915_READ(HDCP2_STATUS_DDI(port)));
>+ ret = -ENXIO;
>+ hdcp->value = DRM_MODE_CONTENT_PROTECTION_DESIRED;
>+ schedule_work(&hdcp->prop_work);
>+ goto out;
>+ }
>+
>+ ret = hdcp->shim->check_2_2_link(intel_dig_port);
>+ if (ret == HDCP_LINK_PROTECTED) {
>+ if (hdcp->value !=
>DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
>+ hdcp->value =
>DRM_MODE_CONTENT_PROTECTION_ENABLED;
>+ schedule_work(&hdcp->prop_work);
>+ }
>+ goto out;
>+ }
>+
>+ DRM_DEBUG_KMS("[%s:%d] HDCP2.2 link failed, retrying auth\n",
>+ connector->base.name, connector->base.base.id);
>+
>+ ret = _intel_hdcp2_disable(connector);
>+ if (ret) {
>+ DRM_ERROR("[%s:%d] Failed to disable hdcp2.2 (%d)\n",
>+ connector->base.name, connector->base.base.id, ret);
>+ hdcp->value = DRM_MODE_CONTENT_PROTECTION_DESIRED;
>+ schedule_work(&hdcp->prop_work);
>+ goto out;
>+ }
>+
>+ ret = _intel_hdcp2_enable(connector);
>+ if (ret) {
>+ DRM_DEBUG_KMS("[%s:%d] Failed to enable hdcp2.2 (%d)\n",
>+ connector->base.name, connector->base.base.id,
>+ ret);
>+ hdcp->value = DRM_MODE_CONTENT_PROTECTION_DESIRED;
>+ schedule_work(&hdcp->prop_work);
>+ goto out;
>+ }
>+
>+out:
>+ mutex_unlock(&hdcp->mutex);
>+ return ret;
>+}
>+
> static void intel_hdcp_check_work(struct work_struct *work) {
> struct intel_hdcp *hdcp = container_of(to_delayed_work(work),
>@@ -1578,7 +1651,10 @@ static void intel_hdcp_check_work(struct work_struct
>*work)
> check_work);
> struct intel_connector *connector = intel_hdcp_to_connector(hdcp);
>
>- if (!intel_hdcp_check_link(connector))
>+ if (!intel_hdcp2_check_link(connector))
>+ schedule_delayed_work(&hdcp->check_work,
>+ DRM_HDCP2_CHECK_PERIOD_MS);
>+ else if (!intel_hdcp_check_link(connector))
> schedule_delayed_work(&hdcp->check_work,
> DRM_HDCP_CHECK_PERIOD_MS);
> }
>@@ -1719,6 +1795,7 @@ int intel_hdcp_init(struct intel_connector *connector,
>int intel_hdcp_enable(struct intel_connector *connector) {
> struct intel_hdcp *hdcp = &connector->hdcp;
>+ unsigned long check_link_interval = DRM_HDCP_CHECK_PERIOD_MS;
> int ret = -EINVAL;
>
> if (!hdcp->shim)
>@@ -1730,18 +1807,19 @@ int intel_hdcp_enable(struct intel_connector
>*connector)
> * 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))
>+ if (intel_hdcp2_capable(connector)) {
> ret = _intel_hdcp2_enable(connector);
>+ if (!ret)
>+ check_link_interval = DRM_HDCP2_CHECK_PERIOD_MS;
>+ }
>
> /* 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) {
>+ schedule_delayed_work(&hdcp->check_work,
>check_link_interval);
> hdcp->value = DRM_MODE_CONTENT_PROTECTION_ENABLED;
> schedule_work(&hdcp->prop_work);
> }
>--
>2.7.4