Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0
/*
 * Functions for dealing with DT resolution
 *
 * Copyright (C) 2012 Pantelis Antoniou <panto@antoniou-consulting.com>
 * Copyright (C) 2012 Texas Instruments Inc.
 */
 
#define pr_fmt(fmt)	"OF: resolver: " fmt
 
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/errno.h>
#include <linux/slab.h>
 
#include "of_private.h"
 
static phandle live_tree_max_phandle(void)
{
<------>struct device_node *node;
<------>phandle phandle;
<------>unsigned long flags;
 
<------>raw_spin_lock_irqsave(&devtree_lock, flags);
<------>phandle = 0;
<------>for_each_of_allnodes(node) {
<------><------>if (node->phandle != OF_PHANDLE_ILLEGAL &&
<------><------><------><------>node->phandle > phandle)
<------><------><------>phandle = node->phandle;
<------>}
<------>raw_spin_unlock_irqrestore(&devtree_lock, flags);
 
<------>return phandle;
}
 
static void adjust_overlay_phandles(struct device_node *overlay,
<------><------>int phandle_delta)
{
<------>struct device_node *child;
<------>struct property *prop;
<------>phandle phandle;
 
<------>/* adjust node's phandle in node */
<------>if (overlay->phandle != 0 && overlay->phandle != OF_PHANDLE_ILLEGAL)
<------><------>overlay->phandle += phandle_delta;
 
<------>/* copy adjusted phandle into *phandle properties */
<------>for_each_property_of_node(overlay, prop) {
 
<------><------>if (of_prop_cmp(prop->name, "phandle") &&
<------><------>    of_prop_cmp(prop->name, "linux,phandle"))
<------><------><------>continue;
 
<------><------>if (prop->length < 4)
<------><------><------>continue;
 
<------><------>phandle = be32_to_cpup(prop->value);
<------><------>if (phandle == OF_PHANDLE_ILLEGAL)
<------><------><------>continue;
 
<------><------>*(__be32 *)prop->value = cpu_to_be32(overlay->phandle);
<------>}
 
<------>for_each_child_of_node(overlay, child)
<------><------>adjust_overlay_phandles(child, phandle_delta);
}
 
static int update_usages_of_a_phandle_reference(struct device_node *overlay,
<------><------>struct property *prop_fixup, phandle phandle)
{
<------>struct device_node *refnode;
<------>struct property *prop;
<------>char *value, *cur, *end, *node_path, *prop_name, *s;
<------>int offset, len;
<------>int err = 0;
 
<------>value = kmemdup(prop_fixup->value, prop_fixup->length, GFP_KERNEL);
<------>if (!value)
<------><------>return -ENOMEM;
 
<------>/* prop_fixup contains a list of tuples of path:property_name:offset */
<------>end = value + prop_fixup->length;
<------>for (cur = value; cur < end; cur += len + 1) {
<------><------>len = strlen(cur);
 
<------><------>node_path = cur;
<------><------>s = strchr(cur, ':');
<------><------>if (!s) {
<------><------><------>err = -EINVAL;
<------><------><------>goto err_fail;
<------><------>}
<------><------>*s++ = '\0';
 
<------><------>prop_name = s;
<------><------>s = strchr(s, ':');
<------><------>if (!s) {
<------><------><------>err = -EINVAL;
<------><------><------>goto err_fail;
<------><------>}
<------><------>*s++ = '\0';
 
<------><------>err = kstrtoint(s, 10, &offset);
<------><------>if (err)
<------><------><------>goto err_fail;
 
<------><------>refnode = __of_find_node_by_full_path(of_node_get(overlay), node_path);
<------><------>if (!refnode)
<------><------><------>continue;
 
<------><------>for_each_property_of_node(refnode, prop) {
<------><------><------>if (!of_prop_cmp(prop->name, prop_name))
<------><------><------><------>break;
<------><------>}
<------><------>of_node_put(refnode);
 
<------><------>if (!prop) {
<------><------><------>err = -ENOENT;
<------><------><------>goto err_fail;
<------><------>}
 
<------><------>if (offset < 0 || offset + sizeof(__be32) > prop->length) {
<------><------><------>err = -EINVAL;
<------><------><------>goto err_fail;
<------><------>}
 
<------><------>*(__be32 *)(prop->value + offset) = cpu_to_be32(phandle);
<------>}
 
err_fail:
<------>kfree(value);
<------>return err;
}
 
/* compare nodes taking into account that 'name' strips out the @ part */
static int node_name_cmp(const struct device_node *dn1,
<------><------>const struct device_node *dn2)
{
<------>const char *n1 = kbasename(dn1->full_name);
<------>const char *n2 = kbasename(dn2->full_name);
 
<------>return of_node_cmp(n1, n2);
}
 
/*
 * Adjust the local phandle references by the given phandle delta.
 *
 * Subtree @local_fixups, which is overlay node __local_fixups__,
 * mirrors the fragment node structure at the root of the overlay.
 *
 * For each property in the fragments that contains a phandle reference,
 * @local_fixups has a property of the same name that contains a list
 * of offsets of the phandle reference(s) within the respective property
 * value(s).  The values at these offsets will be fixed up.
 */
static int adjust_local_phandle_references(struct device_node *local_fixups,
<------><------>struct device_node *overlay, int phandle_delta)
{
<------>struct device_node *child, *overlay_child;
<------>struct property *prop_fix, *prop;
<------>int err, i, count;
<------>unsigned int off;
 
<------>if (!local_fixups)
<------><------>return 0;
 
<------>for_each_property_of_node(local_fixups, prop_fix) {
 
<------><------>/* skip properties added automatically */
<------><------>if (!of_prop_cmp(prop_fix->name, "name") ||
<------><------>    !of_prop_cmp(prop_fix->name, "phandle") ||
<------><------>    !of_prop_cmp(prop_fix->name, "linux,phandle"))
<------><------><------>continue;
 
<------><------>if ((prop_fix->length % 4) != 0 || prop_fix->length == 0)
<------><------><------>return -EINVAL;
<------><------>count = prop_fix->length / sizeof(__be32);
 
<------><------>for_each_property_of_node(overlay, prop) {
<------><------><------>if (!of_prop_cmp(prop->name, prop_fix->name))
<------><------><------><------>break;
<------><------>}
 
<------><------>if (!prop)
<------><------><------>return -EINVAL;
 
<------><------>for (i = 0; i < count; i++) {
<------><------><------>off = be32_to_cpu(((__be32 *)prop_fix->value)[i]);
<------><------><------>if ((off + 4) > prop->length)
<------><------><------><------>return -EINVAL;
 
<------><------><------>be32_add_cpu(prop->value + off, phandle_delta);
<------><------>}
<------>}
 
<------>/*
<------> * These nested loops recurse down two subtrees in parallel, where the
<------> * node names in the two subtrees match.
<------> *
<------> * The roots of the subtrees are the overlay's __local_fixups__ node
<------> * and the overlay's root node.
<------> */
<------>for_each_child_of_node(local_fixups, child) {
 
<------><------>for_each_child_of_node(overlay, overlay_child)
<------><------><------>if (!node_name_cmp(child, overlay_child)) {
<------><------><------><------>of_node_put(overlay_child);
<------><------><------><------>break;
<------><------><------>}
 
<------><------>if (!overlay_child) {
<------><------><------>of_node_put(child);
<------><------><------>return -EINVAL;
<------><------>}
 
<------><------>err = adjust_local_phandle_references(child, overlay_child,
<------><------><------><------>phandle_delta);
<------><------>if (err) {
<------><------><------>of_node_put(child);
<------><------><------>return err;
<------><------>}
<------>}
 
<------>return 0;
}
 
/**
 * of_resolve_phandles - Relocate and resolve overlay against live tree
 *
 * @overlay:	Pointer to devicetree overlay to relocate and resolve
 *
 * Modify (relocate) values of local phandles in @overlay to a range that
 * does not conflict with the live expanded devicetree.  Update references
 * to the local phandles in @overlay.  Update (resolve) phandle references
 * in @overlay that refer to the live expanded devicetree.
 *
 * Phandle values in the live tree are in the range of
 * 1 .. live_tree_max_phandle().  The range of phandle values in the overlay
 * also begin with at 1.  Adjust the phandle values in the overlay to begin
 * at live_tree_max_phandle() + 1.  Update references to the phandles to
 * the adjusted phandle values.
 *
 * The name of each property in the "__fixups__" node in the overlay matches
 * the name of a symbol (a label) in the live tree.  The values of each
 * property in the "__fixups__" node is a list of the property values in the
 * overlay that need to be updated to contain the phandle reference
 * corresponding to that symbol in the live tree.  Update the references in
 * the overlay with the phandle values in the live tree.
 *
 * @overlay must be detached.
 *
 * Resolving and applying @overlay to the live expanded devicetree must be
 * protected by a mechanism to ensure that multiple overlays are processed
 * in a single threaded manner so that multiple overlays will not relocate
 * phandles to overlapping ranges.  The mechanism to enforce this is not
 * yet implemented.
 *
 * Return: %0 on success or a negative error value on error.
 */
int of_resolve_phandles(struct device_node *overlay)
{
<------>struct device_node *child, *local_fixups, *refnode;
<------>struct device_node *tree_symbols, *overlay_fixups;
<------>struct property *prop;
<------>const char *refpath;
<------>phandle phandle, phandle_delta;
<------>int err;
 
<------>tree_symbols = NULL;
 
<------>if (!overlay) {
<------><------>pr_err("null overlay\n");
<------><------>err = -EINVAL;
<------><------>goto out;
<------>}
 
<------>if (!of_node_check_flag(overlay, OF_DETACHED)) {
<------><------>pr_err("overlay not detached\n");
<------><------>err = -EINVAL;
<------><------>goto out;
<------>}
 
<------>phandle_delta = live_tree_max_phandle() + 1;
<------>adjust_overlay_phandles(overlay, phandle_delta);
 
<------>for_each_child_of_node(overlay, local_fixups)
<------><------>if (of_node_name_eq(local_fixups, "__local_fixups__"))
<------><------><------>break;
 
<------>err = adjust_local_phandle_references(local_fixups, overlay, phandle_delta);
<------>if (err)
<------><------>goto out;
 
<------>overlay_fixups = NULL;
 
<------>for_each_child_of_node(overlay, child) {
<------><------>if (of_node_name_eq(child, "__fixups__"))
<------><------><------>overlay_fixups = child;
<------>}
 
<------>if (!overlay_fixups) {
<------><------>err = 0;
<------><------>goto out;
<------>}
 
<------>tree_symbols = of_find_node_by_path("/__symbols__");
<------>if (!tree_symbols) {
<------><------>pr_err("no symbols in root of device tree.\n");
<------><------>err = -EINVAL;
<------><------>goto out;
<------>}
 
<------>for_each_property_of_node(overlay_fixups, prop) {
 
<------><------>/* skip properties added automatically */
<------><------>if (!of_prop_cmp(prop->name, "name"))
<------><------><------>continue;
 
<------><------>err = of_property_read_string(tree_symbols,
<------><------><------><------>prop->name, &refpath);
<------><------>if (err) {
<------><------><------>pr_err("node label '%s' not found in live devicetree symbols table\n",
<------><------><------>       prop->name);
<------><------><------>goto out;
<------><------>}
 
<------><------>refnode = of_find_node_by_path(refpath);
<------><------>if (!refnode) {
<------><------><------>err = -ENOENT;
<------><------><------>goto out;
<------><------>}
 
<------><------>phandle = refnode->phandle;
<------><------>of_node_put(refnode);
 
<------><------>err = update_usages_of_a_phandle_reference(overlay, prop, phandle);
<------><------>if (err)
<------><------><------>break;
<------>}
 
out:
<------>if (err)
<------><------>pr_err("overlay phandle fixup failed: %d\n", err);
<------>of_node_put(tree_symbols);
 
<------>return err;
}
EXPORT_SYMBOL_GPL(of_resolve_phandles);