[Intel-gfx] [PATCH v6 14/35] drm/i915: Implement HDCP2.2 link integrity check
Shankar, Uma
uma.shankar at intel.com
Wed Aug 1 10:45:49 UTC 2018
>-----Original Message-----
>From: C, Ramalingam
>Sent: Saturday, July 14, 2018 8:45 AM
>To: intel-gfx at lists.freedesktop.org; dri-devel at lists.freedesktop.org;
>daniel at ffwll.ch; seanpaul at chromium.org; Winkler, Tomas
><tomas.winkler at intel.com>; Usyskin, Alexander <alexander.usyskin at intel.com>;
>Shankar, Uma <uma.shankar at intel.com>
>Cc: Sharma, Shashank <shashank.sharma at intel.com>; C, Ramalingam
><ramalingam.c at intel.com>
>Subject: [PATCH v6 14/35] 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:
> No Changes.
>v4:
> enum check_link_response is used check the link status [Uma]
>v5:
> Rebased as part of patch reordering.
>v6:
> Required members of intel_hdcp is defined [Sean Paul]
>
>Signed-off-by: Ramalingam C <ramalingam.c at intel.com>
>---
> drivers/gpu/drm/i915/intel_drv.h | 5 +++ drivers/gpu/drm/i915/intel_hdcp.c |
>84 ++++++++++++++++++++++++++++++++++++++-
> include/drm/drm_hdcp.h | 8 ++++
> 3 files changed, 96 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>index ed429a6fb9ab..ce4679a0b530 100644
>--- a/drivers/gpu/drm/i915/intel_drv.h
>+++ b/drivers/gpu/drm/i915/intel_drv.h
>@@ -400,6 +400,9 @@ struct intel_hdcp_shim {
> */
> int (*config_stream_type)(struct intel_digital_port *intel_dig_port,
> void *buf, size_t size);
>+
>+ /* HDCP2.2 Link Integrity Check */
>+ int (*check_2_2_link)(struct intel_digital_port *intel_dig_port);
> };
>
> struct intel_hdcp {
>@@ -442,6 +445,8 @@ struct intel_hdcp {
> * over re-Auth has to be triggered.
> */
> uint32_t seq_num_m;
>+
>+ struct delayed_work hdcp2_check_work;
> };
>
> struct intel_connector {
>diff --git a/drivers/gpu/drm/i915/intel_hdcp.c
>b/drivers/gpu/drm/i915/intel_hdcp.c
>index a08d80c710d7..0a14d8757346 100644
>--- a/drivers/gpu/drm/i915/intel_hdcp.c
>+++ b/drivers/gpu/drm/i915/intel_hdcp.c
>@@ -25,6 +25,8 @@
> 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 void intel_hdcp2_check_work(struct work_struct *work); static
>+int intel_hdcp2_check_link(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); @@ -
>823,6 +825,7 @@ int intel_hdcp_init(struct intel_connector *connector,
> mutex_init(&hdcp->mutex);
> INIT_DELAYED_WORK(&hdcp->check_work, intel_hdcp_check_work);
> INIT_WORK(&hdcp->prop_work, intel_hdcp_prop_work);
>+ INIT_DELAYED_WORK(&hdcp->hdcp2_check_work,
>intel_hdcp2_check_work);
>
> if (hdcp2_supported)
> intel_hdcp2_init(connector);
>@@ -844,8 +847,12 @@ 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)
>+ schedule_delayed_work(&hdcp->hdcp2_check_work,
>+ DRM_HDCP2_CHECK_PERIOD_MS);
>+ }
>
> /* When HDCP2.2 fails, HDCP1.4 will be attempted */
> if (ret && intel_hdcp_capable(connector)) { @@ -1724,3 +1731,78 @@
>static int intel_hdcp2_init(struct intel_connector *connector)
> exit:
> return ret;
> }
>+
>+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;
>+
>+ if (!hdcp->shim)
>+ return -ENOENT;
>+
>+ mutex_lock(&hdcp->mutex);
>+
>+ if (hdcp->value == DRM_MODE_CONTENT_PROTECTION_UNDESIRED)
>+ goto out;
>+
>+ if (!(I915_READ(HDCP2_STATUS_DDI(port)) &
>LINK_ENCRYPTION_STATUS)) {
>+ DRM_ERROR("HDCP check failed: link is not encrypted, %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 == DRM_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_ERROR("[%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_ERROR("[%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_hdcp2_check_work(struct work_struct *work) {
>+ struct intel_hdcp *hdcp = container_of(to_delayed_work(work),
>+ struct intel_hdcp,
>+ hdcp2_check_work);
>+ struct intel_connector *connector = intel_hdcp_to_connector(hdcp);
>+
>+ if (!intel_hdcp2_check_link(connector))
>+ schedule_delayed_work(&hdcp->hdcp2_check_work,
>+ DRM_HDCP2_CHECK_PERIOD_MS);
>+}
>diff --git a/include/drm/drm_hdcp.h b/include/drm/drm_hdcp.h index
>c01cdb1d848d..c4aff185076d 100644
>--- a/include/drm/drm_hdcp.h
>+++ b/include/drm/drm_hdcp.h
>@@ -11,6 +11,14 @@
>
> /* Period of hdcp checks (to ensure we're still authenticated) */
> #define DRM_HDCP_CHECK_PERIOD_MS (128 * 16)
>+#define DRM_HDCP2_CHECK_PERIOD_MS 500
I feel we can optimize this frequency of link integrity check. As per spec, we should
check once every 1 sec, but our frequency here seems to be just double of it.
Other than that looks ok to me.
Reviewed-by: Uma Shankar <uma.shankar at intel.com>
>+
>+enum check_link_response {
>+ DRM_HDCP_LINK_PROTECTED = 0,
>+ DRM_HDCP_TOPOLOGY_CHANGE,
>+ DRM_HDCP_LINK_INTEGRITY_FAILURE,
>+ DRM_HDCP_REAUTH_REQUEST
>+};
>
> /* Shared lengths/masks between HDMI/DVI/DisplayPort */
> #define DRM_HDCP_AN_LEN 8
>--
>2.7.4
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