drm/atomic: Add macros to access existing old/new state, v2.

After atomic commit, these macros should be used in place of
get_existing_state. Also after commit get_xx_state should no longer
be used because it may not have the required locks.

The calls to drm_atomic_get_existing_$obj_state should no longer be
used, and converted over to these new calls.

Changes since v1:
- Expand commit message.
- Deprecate get_existing_*_state functions in the documentation.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1487256430-7625-4-git-send-email-maarten.lankhorst@linux.intel.com
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

include/drm/drm_atomic.h

@@ -277,6 +277,9 @@ int drm_atomic_connector_set_property(struct drm_connector *connector,
  *
  * This function returns the crtc state for the given crtc, or NULL
  * if the crtc is not part of the global atomic state.
+ *
+ * This function is deprecated, @drm_atomic_get_old_crtc_state or
+ * @drm_atomic_get_new_crtc_state should be used instead.
  */
 static inline struct drm_crtc_state *
 drm_atomic_get_existing_crtc_state(struct drm_atomic_state *state,
@@ -285,6 +288,35 @@ drm_atomic_get_existing_crtc_state(struct drm_atomic_state *state,
 	return state->crtcs[drm_crtc_index(crtc)].state;
 }
 
+/**
+ * drm_atomic_get_old_crtc_state - get old crtc state, if it exists
+ * @state: global atomic state object
+ * @crtc: crtc to grab
+ *
+ * This function returns the old crtc state for the given crtc, or
+ * NULL if the crtc is not part of the global atomic state.
+ */
+static inline struct drm_crtc_state *
+drm_atomic_get_old_crtc_state(struct drm_atomic_state *state,
+			      struct drm_crtc *crtc)
+{
+	return state->crtcs[drm_crtc_index(crtc)].old_state;
+}
+/**
+ * drm_atomic_get_new_crtc_state - get new crtc state, if it exists
+ * @state: global atomic state object
+ * @crtc: crtc to grab
+ *
+ * This function returns the new crtc state for the given crtc, or
+ * NULL if the crtc is not part of the global atomic state.
+ */
+static inline struct drm_crtc_state *
+drm_atomic_get_new_crtc_state(struct drm_atomic_state *state,
+			      struct drm_crtc *crtc)
+{
+	return state->crtcs[drm_crtc_index(crtc)].new_state;
+}
+
 /**
  * drm_atomic_get_existing_plane_state - get plane state, if it exists
  * @state: global atomic state object
@@ -292,6 +324,9 @@ drm_atomic_get_existing_crtc_state(struct drm_atomic_state *state,
  *
  * This function returns the plane state for the given plane, or NULL
  * if the plane is not part of the global atomic state.
+ *
+ * This function is deprecated, @drm_atomic_get_old_plane_state or
+ * @drm_atomic_get_new_plane_state should be used instead.
  */
 static inline struct drm_plane_state *
 drm_atomic_get_existing_plane_state(struct drm_atomic_state *state,
@@ -300,6 +335,36 @@ drm_atomic_get_existing_plane_state(struct drm_atomic_state *state,
 	return state->planes[drm_plane_index(plane)].state;
 }
 
+/**
+ * drm_atomic_get_old_plane_state - get plane state, if it exists
+ * @state: global atomic state object
+ * @plane: plane to grab
+ *
+ * This function returns the old plane state for the given plane, or
+ * NULL if the plane is not part of the global atomic state.
+ */
+static inline struct drm_plane_state *
+drm_atomic_get_old_plane_state(struct drm_atomic_state *state,
+			       struct drm_plane *plane)
+{
+	return state->planes[drm_plane_index(plane)].old_state;
+}
+
+/**
+ * drm_atomic_get_new_plane_state - get plane state, if it exists
+ * @state: global atomic state object
+ * @plane: plane to grab
+ *
+ * This function returns the new plane state for the given plane, or
+ * NULL if the plane is not part of the global atomic state.
+ */
+static inline struct drm_plane_state *
+drm_atomic_get_new_plane_state(struct drm_atomic_state *state,
+			       struct drm_plane *plane)
+{
+	return state->planes[drm_plane_index(plane)].new_state;
+}
+
 /**
  * drm_atomic_get_existing_connector_state - get connector state, if it exists
  * @state: global atomic state object
@@ -307,6 +372,9 @@ drm_atomic_get_existing_plane_state(struct drm_atomic_state *state,
  *
  * This function returns the connector state for the given connector,
  * or NULL if the connector is not part of the global atomic state.
+ *
+ * This function is deprecated, @drm_atomic_get_old_connector_state or
+ * @drm_atomic_get_new_connector_state should be used instead.
  */
 static inline struct drm_connector_state *
 drm_atomic_get_existing_connector_state(struct drm_atomic_state *state,
@@ -320,6 +388,46 @@ drm_atomic_get_existing_connector_state(struct drm_atomic_state *state,
 	return state->connectors[index].state;
 }
 
+/**
+ * drm_atomic_get_old_connector_state - get connector state, if it exists
+ * @state: global atomic state object
+ * @connector: connector to grab
+ *
+ * This function returns the old connector state for the given connector,
+ * or NULL if the connector is not part of the global atomic state.
+ */
+static inline struct drm_connector_state *
+drm_atomic_get_old_connector_state(struct drm_atomic_state *state,
+				   struct drm_connector *connector)
+{
+	int index = drm_connector_index(connector);
+
+	if (index >= state->num_connector)
+		return NULL;
+
+	return state->connectors[index].old_state;
+}
+
+/**
+ * drm_atomic_get_new_connector_state - get connector state, if it exists
+ * @state: global atomic state object
+ * @connector: connector to grab
+ *
+ * This function returns the new connector state for the given connector,
+ * or NULL if the connector is not part of the global atomic state.
+ */
+static inline struct drm_connector_state *
+drm_atomic_get_new_connector_state(struct drm_atomic_state *state,
+				   struct drm_connector *connector)
+{
+	int index = drm_connector_index(connector);
+
+	if (index >= state->num_connector)
+		return NULL;
+
+	return state->connectors[index].new_state;
+}
+
 /**
  * __drm_atomic_get_current_plane_state - get current plane state
  * @state: global atomic state object