drm/hdcp: update content protection property with uevent

drm function is defined and exported to update a connector's
content protection property state and to generate a uevent along
with it.

Pekka have completed the Weston DRM-backend review in
https://gitlab.freedesktop.org/wayland/weston/merge_requests/48
and the UAPI for HDCP 2.2 looks good.

The userspace is accepted in Weston.

v2:
  Update only when state is different from old one.
v3:
  KDoc is added [Daniel]
v4:
  KDoc is extended bit more [pekka]
v5:
  Uevent usage is documented at kdoc of "Content Protection" also
  [pekka]

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/320963/?series=57232&rev=14

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index cddb97f754154abf6651bc5d7ab2052e4f98cd3f..354798bad57649898a2f2cc01140afa964929280 100644 (file)
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -983,10 +983,19 @@ static const struct drm_prop_enum_list hdmi_colorspaces[] = {
  *     - If the state is DESIRED, kernel should attempt to re-authenticate the
  *       link whenever possible. This includes across disable/enable, dpms,
  *       hotplug, downstream device changes, link status failures, etc..
- *     - Userspace is responsible for polling the property to determine when
- *       the value transitions from ENABLED to DESIRED. This signifies the link
- *       is no longer protected and userspace should take appropriate action
- *       (whatever that might be).
+ *     - Kernel sends uevent with the connector id and property id through
+ *       @drm_hdcp_update_content_protection, upon below kernel triggered
+ *       scenarios:
+ *             DESIRED -> ENABLED      (authentication success)
+ *             ENABLED -> DESIRED      (termination of authentication)
+ *     - Please note no uevents for userspace triggered property state changes,
+ *       which can't fail such as
+ *             DESIRED/ENABLED -> UNDESIRED
+ *             UNDESIRED -> DESIRED
+ *     - Userspace is responsible for polling the property or listen to uevents
+ *       to determine when the value transitions from ENABLED to DESIRED.
+ *       This signifies the link is no longer protected and userspace should
+ *       take appropriate action (whatever that might be).
  *
  * HDCP Content Type:
  *     This Enum property is used by the userspace to declare the content type

diff --git a/drivers/gpu/drm/drm_hdcp.c b/drivers/gpu/drm/drm_hdcp.c
index ce235fd1c84447aad2058b628928954167efd188..77433ee3d6521f07aa3c8a4617981c4e1426757e 100644 (file)
--- a/drivers/gpu/drm/drm_hdcp.c
+++ b/drivers/gpu/drm/drm_hdcp.c
@@ -374,6 +374,10 @@ DRM_ENUM_NAME_FN(drm_get_hdcp_content_type_name,
  *
  * The content protection will be set to &drm_connector_state.content_protection
  *
+ * When kernel triggered content protection state change like DESIRED->ENABLED
+ * and ENABLED->DESIRED, will use drm_hdcp_update_content_protection() to update
+ * the content protection state of a connector.
+ *
  * Returns:
  * Zero on success, negative errno on failure.
  */
@@ -414,3 +418,33 @@ int drm_connector_attach_content_protection_property(
        return 0;
 }
 EXPORT_SYMBOL(drm_connector_attach_content_protection_property);
+
+/**
+ * drm_hdcp_update_content_protection - Updates the content protection state
+ * of a connector
+ *
+ * @connector: drm_connector on which content protection state needs an update
+ * @val: New state of the content protection property
+ *
+ * This function can be used by display drivers, to update the kernel triggered
+ * content protection state changes of a drm_connector such as DESIRED->ENABLED
+ * and ENABLED->DESIRED. No uevent for DESIRED->UNDESIRED or ENABLED->UNDESIRED,
+ * as userspace is triggering such state change and kernel performs it without
+ * fail.This function update the new state of the property into the connector's
+ * state and generate an uevent to notify the userspace.
+ */
+void drm_hdcp_update_content_protection(struct drm_connector *connector,
+                                       u64 val)
+{
+       struct drm_device *dev = connector->dev;
+       struct drm_connector_state *state = connector->state;
+
+       WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
+       if (state->content_protection == val)
+               return;
+
+       state->content_protection = val;
+       drm_sysfs_connector_status_event(connector,
+                                dev->mode_config.content_protection_property);
+}
+EXPORT_SYMBOL(drm_hdcp_update_content_protection);

diff --git a/include/drm/drm_hdcp.h b/include/drm/drm_hdcp.h
index 82447af98aa26390989f752202c6f901cb98d961..06a11202a0976d80d660eebd229f0e7c048e54c5 100644 (file)
--- a/include/drm/drm_hdcp.h
+++ b/include/drm/drm_hdcp.h
@@ -292,6 +292,8 @@ bool drm_hdcp_check_ksvs_revoked(struct drm_device *dev,
                                 u8 *ksvs, u32 ksv_count);
 int drm_connector_attach_content_protection_property(
                struct drm_connector *connector, bool hdcp_content_type);
+void drm_hdcp_update_content_protection(struct drm_connector *connector,
+                                       u64 val);
 
 /* Content Type classification for HDCP2.2 vs others */
 #define DRM_MODE_HDCP_CONTENT_TYPE0            0