[PATCH v10 07/40] drm/i915: hdcp1.4 CP_IRQ handling and SW encryption tracking

Ramalingam C
2019-01-31T06:59:23Z

"hdcp_encrypted" flag is defined to denote the HDCP1.4 encryption status.
This SW tracking is used to determine the need for real hdcp1.4 disable
and hdcp_check_link upon CP_IRQ.

On CP_IRQ we filter the CP_IRQ related to the states like Link failure
and reauthentication req etc and handle them in hdcp_check_link.
CP_IRQ corresponding to the authentication msg availability are ignored.

WARN_ON is added for the abrupt stop of HDCP encryption of a port.

v2:
bool is used in struct for the cleaner coding. [Daniel]
check_link work_fn is scheduled for cp_irq handling [Daniel]

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
---
drivers/gpu/drm/i915/intel_dp.c | 2 +-
drivers/gpu/drm/i915/intel_drv.h | 5 ++-
drivers/gpu/drm/i915/intel_hdcp.c | 73 ++++++++++++++++++++++++++++-----------
3 files changed, 58 insertions(+), 22 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 815ee68efa2f..9ce05819fc11 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4776,7 +4776,7 @@ static void intel_dp_check_service_irq(struct intel_dp *intel_dp)
intel_dp_handle_test_request(intel_dp);

if (val & DP_CP_IRQ)
- intel_hdcp_check_link(intel_dp->attached_connector);
+ intel_hdcp_handle_cp_irq(intel_dp->attached_connector);

if (val & DP_SINK_SPECIFIC_IRQ)
DRM_DEBUG_DRIVER("Sink specific irq unhandled\n");
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 63e009286d5f..13a41e8cf4ff 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -399,6 +399,9 @@ struct intel_hdcp {
struct delayed_work check_work;
struct work_struct prop_work;

+ /* HDCP1.4 Encryption status */
+ bool hdcp_encrypted;
+
/* HDCP2.2 related definitions */
/* Flag indicates whether this connector supports HDCP2.2 or not. */
bool hdcp2_supported;
@@ -2073,10 +2076,10 @@ int intel_hdcp_init(struct intel_connector *connector,
bool hdcp2_supported);
int intel_hdcp_enable(struct intel_connector *connector);
int intel_hdcp_disable(struct intel_connector *connector);
-int intel_hdcp_check_link(struct intel_connector *connector);
bool is_hdcp_supported(struct drm_i915_private *dev_priv, enum port port);
bool intel_hdcp_capable(struct intel_connector *connector);
bool is_hdcp2_supported(struct drm_i915_private *dev_priv);
+void intel_hdcp_handle_cp_irq(struct intel_connector *connector);

/* intel_psr.c */
#define CAN_PSR(dev_priv) (HAS_PSR(dev_priv) && dev_priv->psr.sink_support)
diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c
index e0bb5f32ba90..c1b057f1501b 100644
--- a/drivers/gpu/drm/i915/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/intel_hdcp.c
@@ -74,6 +74,16 @@ bool intel_hdcp_capable(struct intel_connector *connector)
return capable;
}

+static inline bool intel_hdcp_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(PORT_HDCP_STATUS(port));
+ return reg & HDCP_STATUS_ENC;
+}
+
static int intel_hdcp_poll_ksv_fifo(struct intel_digital_port *intel_dig_port,
const struct intel_hdcp_shim *shim)
{
@@ -668,6 +678,7 @@ static int _intel_hdcp_disable(struct intel_connector *connector)
DRM_DEBUG_KMS("[%s:%d] HDCP is being disabled...\n",
connector->base.name, connector->base.base.id);

+ hdcp->hdcp_encrypted = false;
I915_WRITE(PORT_HDCP_CONF(port), 0);
if (intel_wait_for_register(dev_priv, PORT_HDCP_STATUS(port), ~0, 0,
ENCRYPT_STATUS_CHANGE_TIMEOUT_MS)) {
@@ -713,8 +724,10 @@ static int _intel_hdcp_enable(struct intel_connector *connector)
/* Incase of authentication failures, HDCP spec expects reauth. */
for (i = 0; i < tries; i++) {
ret = intel_hdcp_auth(conn_to_dig_port(connector), hdcp->shim);
- if (!ret)
+ if (!ret) {
+ hdcp->hdcp_encrypted = true;
return 0;
+ }

DRM_DEBUG_KMS("HDCP Auth failure (%d)\n", ret);

@@ -741,16 +754,17 @@ int intel_hdcp_check_link(struct intel_connector *connector)
enum port port = intel_dig_port->base.port;
int ret = 0;

- if (!hdcp->shim)
- return -ENOENT;
-
mutex_lock(&hdcp->mutex);

- if (hdcp->value == DRM_MODE_CONTENT_PROTECTION_UNDESIRED)
+ /* Check_link valid only when HDCP1.4 is enabled */
+ if (hdcp->value != DRM_MODE_CONTENT_PROTECTION_ENABLED ||
+ !hdcp->hdcp_encrypted) {
+ ret = -EINVAL;
goto out;
+ }

- if (!(I915_READ(PORT_HDCP_STATUS(port)) & HDCP_STATUS_ENC)) {
- DRM_ERROR("%s:%d HDCP check failed: link is not encrypted,%x\n",
+ if (WARN_ON(!intel_hdcp_in_use(connector))) {
+ DRM_ERROR("%s:%d HDCP link stopped encryption,%x\n",
connector->base.name, connector->base.base.id,
I915_READ(PORT_HDCP_STATUS(port)));
ret = -ENXIO;
@@ -791,18 +805,6 @@ int intel_hdcp_check_link(struct intel_connector *connector)
return ret;
}

-static void intel_hdcp_check_work(struct work_struct *work)
-{
- struct intel_hdcp *hdcp = container_of(to_delayed_work(work),
- struct intel_hdcp,
- check_work);
- struct intel_connector *connector = intel_hdcp_to_connector(hdcp);
-
- if (!intel_hdcp_check_link(connector))
- schedule_delayed_work(&hdcp->check_work,
- DRM_HDCP_CHECK_PERIOD_MS);
-}
-
static void intel_hdcp_prop_work(struct work_struct *work)
{
struct intel_hdcp *hdcp = container_of(work, struct intel_hdcp,
@@ -1120,6 +1122,18 @@ int hdcp2_deauthenticate_port(struct intel_connector *connector)
return hdcp2_close_mei_session(connector);
}

+static void intel_hdcp_check_work(struct work_struct *work)
+{
+ struct intel_hdcp *hdcp = container_of(to_delayed_work(work),
+ struct intel_hdcp,
+ check_work);
+ struct intel_connector *connector = intel_hdcp_to_connector(hdcp);
+
+ if (!intel_hdcp_check_link(connector))
+ schedule_delayed_work(&hdcp->check_work,
+ DRM_HDCP_CHECK_PERIOD_MS);
+}
+
static int i915_hdcp_component_bind(struct device *i915_kdev,
struct device *mei_kdev, void *data)
{
@@ -1288,7 +1302,8 @@ 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->hdcp_encrypted)
+ ret = _intel_hdcp_disable(connector);
}

mutex_unlock(&hdcp->mutex);
@@ -1328,3 +1343,21 @@ void intel_hdcp_atomic_check(struct drm_connector *connector,
new_state->crtc);
crtc_state->mode_changed = true;
}
+
+/* Handles the CP_IRQ raised from the DP HDCP sink */
+void intel_hdcp_handle_cp_irq(struct intel_connector *connector)
+{
+ struct intel_hdcp *hdcp = &connector->hdcp;
+
+ if (!hdcp->shim)
+ return;
+
+ /*
+ * CP_IRQ could be triggered due to 1. HDCP2.2 auth msgs availability,
+ * 2. link failure and 3. repeater reauth request. At present we dont
+ * handle the CP_IRQ for the HDCP2.2 auth msg availability for read.
+ * To handle other two causes for CP_IRQ we have the work_fn which is
+ * scheduled here.
+ */
+ schedule_delayed_work(&hdcp->check_work, 0);
+}
--
2.7.4

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