linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * Functions for working with device tree overlays

 *

 * Copyright (C) 2012 Pantelis Antoniou <panto@antoniou-consulting.com>

 * Copyright (C) 2012 Texas Instruments Inc.

 */

​

#define pr_fmt(fmt) "OF: overlay: " fmt

​

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/of_device.h>

#include <linux/of_fdt.h>

#include <linux/string.h>

#include <linux/ctype.h>

#include <linux/errno.h>

#include <linux/slab.h>

#include <linux/libfdt.h>

#include <linux/err.h>

#include <linux/idr.h>

​

#include "of_private.h"

​

/**

 * struct target - info about current target node as recursing through overlay

 * @np:         node where current level of overlay will be applied

 * @in_livetree:    @np is a node in the live devicetree

 *

 * Used in the algorithm to create the portion of a changeset that describes

 * an overlay fragment, which is a devicetree subtree.  Initially @np is a node

 * in the live devicetree where the overlay subtree is targeted to be grafted

 * into.  When recursing to the next level of the overlay subtree, the target

 * also recurses to the next level of the live devicetree, as long as overlay

 * subtree node also exists in the live devicetree.  When a node in the overlay

 * subtree does not exist at the same level in the live devicetree, target->np

 * points to a newly allocated node, and all subsequent targets in the subtree

 * will be newly allocated nodes.

 */

struct target {

    struct device_node *np;

    bool in_livetree;

};

​

/**

 * struct fragment - info about fragment nodes in overlay expanded device tree

 * @target: target of the overlay operation

 * @overlay:    pointer to the __overlay__ node

 */

struct fragment {

    struct device_node *overlay;

    struct device_node *target;

};

​

/**

 * struct overlay_changeset

 * @id:         changeset identifier

 * @ovcs_list:      list on which we are located

 * @fdt:        FDT that was unflattened to create @overlay_tree

 * @overlay_tree:   expanded device tree that contains the fragment nodes

 * @count:      count of fragment structures

 * @fragments:      fragment nodes in the overlay expanded device tree