drm/vkms: Subclass plane state

Subclass plane state struct to enable storing driver's private
state. This patch only adds the base drm_plane_state struct and
the atomic functions that handle it.
Signed-off-by: Haneen Mohammed <hamohammed.sa@gmail.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/c35c512c8987a7255aac94a9eb985d2dd3e6c90d.1533171495.git.hamohammed.sa@gmail.com

drivers/gpu/drm/vkms/vkms_drv.h

@@ -20,6 +20,14 @@ static const u32 vkms_formats[] = {
 	DRM_FORMAT_XRGB8888,
 };
 
+/**
+ * vkms_plane_state - Driver specific plane state
+ * @base: base plane state
+ */
+struct vkms_plane_state {
+	struct drm_plane_state base;
+};
+
 /**
  * vkms_crtc_state - Driver specific CRTC state
  * @base: base CRTC state
@@ -63,6 +71,9 @@ struct vkms_gem_object {
 #define to_vkms_crtc_state(target)\
 	container_of(target, struct vkms_crtc_state, base)
 
+#define to_vkms_plane_state(target)\
+	container_of(target, struct vkms_plane_state, base)
+
 /* CRTC */
 int vkms_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
 		   struct drm_plane *primary, struct drm_plane *cursor);

drivers/gpu/drm/vkms/vkms_plane.c

@@ -12,13 +12,54 @@
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
 
+static struct drm_plane_state *
+vkms_plane_duplicate_state(struct drm_plane *plane)
+{
+	struct vkms_plane_state *vkms_state;
+
+	vkms_state = kzalloc(sizeof(*vkms_state), GFP_KERNEL);
+	if (!vkms_state)
+		return NULL;
+
+	__drm_atomic_helper_plane_duplicate_state(plane,
+						  &vkms_state->base);
+
+	return &vkms_state->base;
+}
+
+static void vkms_plane_destroy_state(struct drm_plane *plane,
+				     struct drm_plane_state *old_state)
+{
+	struct vkms_plane_state *vkms_state = to_vkms_plane_state(old_state);
+
+	__drm_atomic_helper_plane_destroy_state(old_state);
+	kfree(vkms_state);
+}
+
+static void vkms_plane_reset(struct drm_plane *plane)
+{
+	struct vkms_plane_state *vkms_state;
+
+	if (plane->state)
+		vkms_plane_destroy_state(plane, plane->state);
+
+	vkms_state = kzalloc(sizeof(*vkms_state), GFP_KERNEL);
+	if (!vkms_state) {
+		DRM_ERROR("Cannot allocate vkms_plane_state\n");
+		return;
+	}
+
+	plane->state = &vkms_state->base;
+	plane->state->plane = plane;
+}
+
 static const struct drm_plane_funcs vkms_plane_funcs = {
 	.update_plane		= drm_atomic_helper_update_plane,
 	.disable_plane		= drm_atomic_helper_disable_plane,
 	.destroy		= drm_plane_cleanup,
-	.reset			= drm_atomic_helper_plane_reset,
-	.atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
-	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
+	.reset			= vkms_plane_reset,
+	.atomic_duplicate_state = vkms_plane_duplicate_state,
+	.atomic_destroy_state	= vkms_plane_destroy_state,
 };
 
 static void vkms_primary_plane_update(struct drm_plane *plane,