drm/atomic: integrate modeset lock with private objects

Follow the same pattern of locking as with other state objects. This
avoids boilerplate in the driver.

Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20181022123122.30468-1-boris.brezillon@bootlin.com

2 files changed, 45 insertions, 1 deletions

diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
index f9b35834c45d..cac4a1b6b0e8 100644
--- a/include/drm/drm_atomic.h
+++ b/include/drm/drm_atomic.h
@@ -228,9 +228,31 @@ struct drm_private_state_funcs {
  * Currently only tracks the state update functions and the opaque driver
  * private state itself, but in the future might also track which
  * &drm_modeset_lock is required to duplicate and update this object's state.
+ *
+ * All private objects must be initialized before the DRM device they are
+ * attached to is registered to the DRM subsystem (call to drm_dev_register())
+ * and should stay around until this DRM device is unregistered (call to
+ * drm_dev_unregister()). In other words, private objects lifetime is tied
+ * to the DRM device lifetime. This implies that:
+ *
+ * 1/ all calls to drm_atomic_private_obj_init() must be done before calling
+ *    drm_dev_register()
+ * 2/ all calls to drm_atomic_private_obj_fini() must be done after calling
+ *    drm_dev_unregister()
  */
 struct drm_private_obj {
 	/**
+	 * @head: List entry used to attach a private object to a &drm_device
+	 * (queued to &drm_mode_config.privobj_list).
+	 */
+	struct list_head head;
+
+	/**
+	 * @lock: Modeset lock to protect the state object.
+	 */
+	struct drm_modeset_lock lock;
+
+	/**
 	 * @state: Current atomic state for this driver private object.
 	 */
 	struct drm_private_state *state;
@@ -245,6 +267,18 @@ struct drm_private_obj {
 };
 
 /**
+ * drm_for_each_privobj() - private object iterator
+ *
+ * @privobj: pointer to the current private object. Updated after each
+ *	     iteration
+ * @dev: the DRM device we want get private objects from
+ *
+ * Allows one to iterate over all private objects attached to @dev
+ */
+#define drm_for_each_privobj(privobj, dev) \
+	list_for_each_entry(privobj, &(dev)->mode_config.privobj_list, head)
+
+/**
  * struct drm_private_state - base struct for driver private object state
  * @state: backpointer to global drm_atomic_state
  *
@@ -400,7 +434,8 @@ struct drm_connector_state * __must_check
 drm_atomic_get_connector_state(struct drm_atomic_state *state,
 			       struct drm_connector *connector);
 
-void drm_atomic_private_obj_init(struct drm_private_obj *obj,
+void drm_atomic_private_obj_init(struct drm_device *dev,
+				 struct drm_private_obj *obj,
 				 struct drm_private_state *state,
 				 const struct drm_private_state_funcs *funcs);
 void drm_atomic_private_obj_fini(struct drm_private_obj *obj);
diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 5dbeabdbaf91..d1e27836e0cd 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -512,6 +512,15 @@ struct drm_mode_config {
 	 */
 	struct list_head property_list;
 
+	/**
+	 * @privobj_list:
+	 *
+	 * List of private objects linked with &drm_private_obj.head. This is
+	 * invariant over the lifetime of a device and hence doesn't need any
+	 * locks.
+	 */
+	struct list_head privobj_list;
+
 	int min_width, min_height;
 	int max_width, max_height;
 	const struct drm_mode_config_funcs *funcs;