On Monday 14 May 2018 03:15 PM, Shankar, Uma wrote:

-----Original Message-----
From: dri-devel [mailto:dri-devel-boun...@lists.freedesktop.org] On Behalf Of
Ramalingam C
Sent: Tuesday, April 3, 2018 7:28 PM
To: intel-...@lists.freedesktop.org; dri-devel@lists.freedesktop.org;
seanp...@chromium.org; dan...@ffwll.ch; ch...@chris-wilson.co.uk;
jani.nik...@linux.intel.com; Winkler, Tomas <tomas.wink...@intel.com>;
Usyskin, Alexander <alexander.usys...@intel.com>
Cc: Vivi, Rodrigo <rodrigo.v...@intel.com>
Subject: [PATCH v3 27/40] 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:
  No Changes.

Signed-off-by: Ramalingam C <ramalinga...@intel.com>
---
drivers/gpu/drm/i915/intel_hdcp.c | 81
++++++++++++++++++++++++++++++++++++++-
include/drm/drm_hdcp.h            |  8 ++++
2 files changed, 88 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_hdcp.c
b/drivers/gpu/drm/i915/intel_hdcp.c
index 005627746ca5..e2aec73aefe3 100644
--- a/drivers/gpu/drm/i915/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/intel_hdcp.c
@@ -23,6 +23,8 @@

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_poll_ksv_fifo(struct intel_digital_port *intel_dig_port,
                                    const struct intel_hdcp_shim *shim) @@ -
1456,6 +1458,83 @@ static int _intel_hdcp2_enable(struct intel_connector
*connector)

        hdcp->hdcp_value = DRM_MODE_CONTENT_PROTECTION_ENABLED;
        schedule_work(&hdcp->hdcp_prop_work);
-
+       schedule_delayed_work(&hdcp->hdcp2_check_work,
+                             DRM_HDCP2_CHECK_PERIOD_MS);
        return 0;
}
+
+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->hdcp_shim)
+               return -ENOENT;
+
+       mutex_lock(&hdcp->hdcp_mutex);
+
+       if (hdcp->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->hdcp_value =
DRM_MODE_CONTENT_PROTECTION_DESIRED;
+               schedule_work(&hdcp->hdcp_prop_work);
+               goto out;
+       }
+
+       ret = hdcp->hdcp_shim->check_2_2_link(intel_dig_port);
Check " hdcp->hdcp_shim->check_2_2_link " for NULL.
check_2_2_link is essential func ptr. Dont think it will be good to check on each loop.
Wondering if I need to check for the essential func ptr at init itself.

--Ram

+       if (!ret) {
Here actually we are comparing the ret == DRM_HDCP_LINK_PROTECTED indirectly here. I will make it explicit, hence we can have the enum definition at this patch itself.
+               if (hdcp->hdcp_value !=
DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
+                       hdcp->hdcp_value =
DRM_MODE_CONTENT_PROTECTION_ENABLED;
+                       schedule_work(&hdcp->hdcp_prop_work);
+               }
+               goto out;
+       }
+
+       DRM_INFO("[%s:%d] HDCP2.2 link failed, retrying authentication\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->hdcp_value =
DRM_MODE_CONTENT_PROTECTION_DESIRED;
+               schedule_work(&hdcp->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->hdcp_value =
DRM_MODE_CONTENT_PROTECTION_DESIRED;
+               schedule_work(&hdcp->hdcp_prop_work);
+               goto out;
+       }
+
+out:
+       mutex_unlock(&hdcp->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 = container_of(hdcp,
+                                               struct intel_connector,
+                                               hdcp);
+
+       if (!intel_hdcp2_check_link(connector))
A print saying "link not active" will be good, since this was supposed to 
re-schedule itself and
won't do it again if this doesn’t happen.
We dont have any usage of such log. Any link failure will be reported as errors already.

+               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
f3f28414b189..b0601215c798 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
+
+enum check_link_response {
Don't think this patch uses any of these enums. Add it where its first used.
Addressed above.

--Ram

+       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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