// 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);