drivers/of/resolver.c - linux - Git at Google

 // 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/cleanup.h>
 #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;
 	const 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,
 		const struct property *prop_fixup, phandle phandle)
 {
 	struct device_node *refnode;
 	const struct property *prop;
 	char *value __free(kfree) = kmemdup(prop_fixup->value, prop_fixup->length, GFP_KERNEL);
 	char *cur, *end, *node_path, *prop_name, *s;
 	int offset, len;
 	int err = 0;

 	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)
 			return -EINVAL;
 		*s++ = '\0';

 		prop_name = s;
 		s = strchr(s, ':');
 		if (!s)
 			return -EINVAL;
 		*s++ = '\0';

 		err = kstrtoint(s, 10, &offset);
 		if (err)
 			return err;

 		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)
 			return -ENOENT;

 		if (offset < 0 || offset + sizeof(__be32) > prop->length)
 			return -EINVAL;

 		*(__be32 *)(prop->value + offset) = cpu_to_be32(phandle);
 	}

 	return 0;
 }

 /* 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(const struct device_node *local_fixups,
 		const struct device_node *overlay, int phandle_delta)
 {
 	struct device_node *overlay_child;
 	const 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 (is_pseudo_property(prop_fix->name))
 			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_scoped(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)
 			return -EINVAL;

 		err = adjust_local_phandle_references(child, overlay_child,
 				phandle_delta);
 		if (err)
 			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, *refnode;
 	struct device_node *overlay_fixups;
 	struct device_node __free(device_node) *local_fixups = NULL;
 	struct property *prop;
 	const char *refpath;
 	phandle phandle, phandle_delta;
 	int err;

 	if (!overlay) {
 		pr_err("null overlay\n");
 		return -EINVAL;
 	}

 	if (!of_node_check_flag(overlay, OF_DETACHED)) {
 		pr_err("overlay not detached\n");
 		return -EINVAL;
 	}

 	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)
 		return err;

 	overlay_fixups = NULL;

 	for_each_child_of_node(overlay, child) {
 		if (of_node_name_eq(child, "__fixups__"))
 			overlay_fixups = child;
 	}

 	if (!overlay_fixups)
 		return 0;

 	struct device_node __free(device_node) *tree_symbols = of_find_node_by_path("/__symbols__");
 	if (!tree_symbols) {
 		pr_err("no symbols in root of device tree.\n");
 		return -EINVAL;
 	}

 	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);
 			return err;
 		}

 		refnode = of_find_node_by_path(refpath);
 		if (!refnode)
 			return -ENOENT;

 		phandle = refnode->phandle;
 		of_node_put(refnode);

 		err = update_usages_of_a_phandle_reference(overlay, prop, phandle);
 		if (err)
 			break;
 	}

 	if (err)
 		pr_err("overlay phandle fixup failed: %d\n", err);
 	return err;
 }
 EXPORT_SYMBOL_GPL(of_resolve_phandles);
	// 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/cleanup.h>
	#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;
	const 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,
	const struct property *prop_fixup, phandle phandle)
	{
	struct device_node *refnode;
	const struct property *prop;
	char *value __free(kfree) = kmemdup(prop_fixup->value, prop_fixup->length, GFP_KERNEL);
	char cur, end, node_path, prop_name, *s;
	int offset, len;
	int err = 0;

	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)
	return -EINVAL;
	*s++ = '\0';

	prop_name = s;
	s = strchr(s, ':');
	if (!s)
	return -EINVAL;
	*s++ = '\0';

	err = kstrtoint(s, 10, &offset);
	if (err)
	return err;

	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)
	return -ENOENT;

	if (offset < 0 \|\| offset + sizeof(__be32) > prop->length)
	return -EINVAL;

	(__be32 )(prop->value + offset) = cpu_to_be32(phandle);
	}

	return 0;
	}

	/* 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(const struct device_node *local_fixups,
	const struct device_node *overlay, int phandle_delta)
	{
	struct device_node *overlay_child;
	const 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 (is_pseudo_property(prop_fix->name))
	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_scoped(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)
	return -EINVAL;

	err = adjust_local_phandle_references(child, overlay_child,
	phandle_delta);
	if (err)
	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, refnode;
	struct device_node *overlay_fixups;
	struct device_node __free(device_node) *local_fixups = NULL;
	struct property *prop;
	const char *refpath;
	phandle phandle, phandle_delta;
	int err;

	if (!overlay) {
	pr_err("null overlay\n");
	return -EINVAL;
	}

	if (!of_node_check_flag(overlay, OF_DETACHED)) {
	pr_err("overlay not detached\n");
	return -EINVAL;
	}

	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)
	return err;

	overlay_fixups = NULL;

	for_each_child_of_node(overlay, child) {
	if (of_node_name_eq(child, "__fixups__"))
	overlay_fixups = child;
	}

	if (!overlay_fixups)
	return 0;

	struct device_node __free(device_node) *tree_symbols = of_find_node_by_path("/__symbols__");
	if (!tree_symbols) {
	pr_err("no symbols in root of device tree.\n");
	return -EINVAL;
	}

	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);
	return err;
	}

	refnode = of_find_node_by_path(refpath);
	if (!refnode)
	return -ENOENT;

	phandle = refnode->phandle;
	of_node_put(refnode);

	err = update_usages_of_a_phandle_reference(overlay, prop, phandle);
	if (err)
	break;
	}

	if (err)
	pr_err("overlay phandle fixup failed: %d\n", err);
	return err;
	}
	EXPORT_SYMBOL_GPL(of_resolve_phandles);