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

Daniel Vetter
2019-01-31T07:56:54Z

On Thu, Jan 31, 2019 at 12:29:23PM +0530, Ramalingam C wrote:
> "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]

Just doing a delta-review, v2 addresses my comment about synchronization
with the worker, so

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

>
> 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
>

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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