/* * Procedures for creating, accessing and interpreting the device tree. * * Paul Mackerras	August 1996. * Copyright (C) 1996-2005 Paul Mackerras. * *  Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner. *    {engebret|bergner}@us.ibm.com * *  Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net * *  Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and *  Grant Likely. * *      This program is free software; you can redistribute it and/or *      modify it under the terms of the GNU General Public License *      as published by the Free Software Foundation; either version *      2 of the License, or (at your option) any later version. */#include <linux/console.h>#include <linux/ctype.h>#include <linux/cpu.h>#include <linux/module.h>#include <linux/of.h>#include <linux/of_graph.h>#include <linux/spinlock.h>#include <linux/slab.h>#include <linux/string.h>#include <linux/proc_fs.h> #include "of_private.h" LIST_HEAD(aliases_lookup); struct device_node *of_root;EXPORT_SYMBOL(of_root);struct device_node *of_chosen;struct device_node *of_aliases;struct device_node *of_stdout;static const char *of_stdout_options; struct kset *of_kset; /* * Used to protect the of_aliases, to hold off addition of nodes to sysfs. * This mutex must be held whenever modifications are being made to the * device tree. The of_{attach,detach}_node() and * of_{add,remove,update}_property() helpers make sure this happens. */DEFINE_MUTEX(of_mutex); /* use when traversing tree through the child, sibling, * or parent members of struct device_node. */DEFINE_RAW_SPINLOCK(devtree_lock); int of_n_addr_cells(struct device_node *np){	const __be32 *ip; 	do {		if (np->parent)			np = np->parent;		ip = of_get_property(np, "#address-cells", NULL);		if (ip)			return be32_to_cpup(ip);	} while (np->parent);	/* No #address-cells property for the root node */	return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;}EXPORT_SYMBOL(of_n_addr_cells); int of_n_size_cells(struct device_node *np){	const __be32 *ip; 	do {		if (np->parent)			np = np->parent;		ip = of_get_property(np, "#size-cells", NULL);		if (ip)			return be32_to_cpup(ip);	} while (np->parent);	/* No #size-cells property for the root node */	return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;}EXPORT_SYMBOL(of_n_size_cells); #ifdef CONFIG_NUMAint __weak of_node_to_nid(struct device_node *np){	return NUMA_NO_NODE;}#endif #ifndef CONFIG_OF_DYNAMICstatic void of_node_release(struct kobject *kobj){	/* Without CONFIG_OF_DYNAMIC, no nodes gets freed */}#endif /* CONFIG_OF_DYNAMIC */ struct kobj_type of_node_ktype = {	.release = of_node_release,}; static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,				struct bin_attribute *bin_attr, char *buf,				loff_t offset, size_t count){	struct property *pp = container_of(bin_attr, struct property, attr);	return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);} static const char *safe_name(struct kobject *kobj, const char *orig_name){	const char *name = orig_name;	struct kernfs_node *kn;	int i = 0; 	/* don't be a hero. After 16 tries give up */	while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) {		sysfs_put(kn);		if (name != orig_name)			kfree(name);		name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);	} 	if (name != orig_name)		pr_warn("device-tree: Duplicate name in %s, renamed to \"%s\"\n",			kobject_name(kobj), name);	return name;} int __of_add_property_sysfs(struct device_node *np, struct property *pp){	int rc; 	/* Important: Don't leak passwords */	bool secure = strncmp(pp->name, "security-", 9) == 0; 	if (!IS_ENABLED(CONFIG_SYSFS))		return 0; 	if (!of_kset || !of_node_is_attached(np))		return 0; 	sysfs_bin_attr_init(&pp->attr);	pp->attr.attr.name = safe_name(&np->kobj, pp->name);	pp->attr.attr.mode = secure ? S_IRUSR : S_IRUGO;	pp->attr.size = secure ? 0 : pp->length;	pp->attr.read = of_node_property_read; 	rc = sysfs_create_bin_file(&np->kobj, &pp->attr);	WARN(rc, "error adding attribute %s to node %s\n", pp->name, np->full_name);	return rc;} int __of_attach_node_sysfs(struct device_node *np){	const char *name;	struct property *pp;	int rc; 	if (!IS_ENABLED(CONFIG_SYSFS))		return 0; 	if (!of_kset)		return 0; 	np->kobj.kset = of_kset;	if (!np->parent) {		/* Nodes without parents are new top level trees */		rc = kobject_add(&np->kobj, NULL, "%s",				 safe_name(&of_kset->kobj, "base"));	} else {		name = safe_name(&np->parent->kobj, kbasename(np->full_name));		if (!name || !name[0])			return -EINVAL; 		rc = kobject_add(&np->kobj, &np->parent->kobj, "%s", name);	}	if (rc)		return rc; 	for_each_property_of_node(np, pp)		__of_add_property_sysfs(np, pp); 	return 0;} void __init of_core_init(void){	struct device_node *np; 	/* Create the kset, and register existing nodes */	mutex_lock(&of_mutex);	of_kset = kset_create_and_add("devicetree", NULL, firmware_kobj);	if (!of_kset) {		mutex_unlock(&of_mutex);		pr_err("devicetree: failed to register existing nodes\n");		return;	}	for_each_of_allnodes(np)		__of_attach_node_sysfs(np);	mutex_unlock(&of_mutex); 	/* Symlink in /proc as required by userspace ABI */	if (of_root)		proc_symlink("device-tree", NULL, "/sys/firmware/devicetree/base");} static struct property *__of_find_property(const struct device_node *np,					   const char *name, int *lenp){	struct property *pp; 	if (!np)		return NULL; 	for (pp = np->properties; pp; pp = pp->next) {		if (of_prop_cmp(pp->name, name) == 0) {			if (lenp)				*lenp = pp->length;			break;		}	} 	return pp;} struct property *of_find_property(const struct device_node *np,				  const char *name,				  int *lenp){	struct property *pp;	unsigned long flags; 	raw_spin_lock_irqsave(&devtree_lock, flags);	pp = __of_find_property(np, name, lenp);	raw_spin_unlock_irqrestore(&devtree_lock, flags); 	return pp;}EXPORT_SYMBOL(of_find_property); struct device_node *__of_find_all_nodes(struct device_node *prev){	struct device_node *np;	if (!prev) {		np = of_root;	} else if (prev->child) {		np = prev->child;	} else {		/* Walk back up looking for a sibling, or the end of the structure */		np = prev;		while (np->parent && !np->sibling)			np = np->parent;		np = np->sibling; /* Might be null at the end of the tree */	}	return np;} /** * of_find_all_nodes - Get next node in global list * @prev:	Previous node or NULL to start iteration *		of_node_put() will be called on it * * Returns a node pointer with refcount incremented, use * of_node_put() on it when done. */struct device_node *of_find_all_nodes(struct device_node *prev){	struct device_node *np;	unsigned long flags; 	raw_spin_lock_irqsave(&devtree_lock, flags);	np = __of_find_all_nodes(prev);	of_node_get(np);	of_node_put(prev);	raw_spin_unlock_irqrestore(&devtree_lock, flags);	return np;}EXPORT_SYMBOL(of_find_all_nodes); /* * Find a property with a given name for a given node * and return the value. */const void *__of_get_property(const struct device_node *np,			      const char *name, int *lenp){	struct property *pp = __of_find_property(np, name, lenp); 	return pp ? pp->value : NULL;} /* * Find a property with a given name for a given node * and return the value. */const void *of_get_property(const struct device_node *np, const char *name,			    int *lenp){	struct property *pp = of_find_property(np, name, lenp); 	return pp ? pp->value : NULL;}EXPORT_SYMBOL(of_get_property); /* * arch_match_cpu_phys_id - Match the given logical CPU and physical id * * @cpu: logical cpu index of a core/thread * @phys_id: physical identifier of a core/thread * * CPU logical to physical index mapping is architecture specific. * However this __weak function provides a default match of physical * id to logical cpu index. phys_id provided here is usually values read * from the device tree which must match the hardware internal registers. * * Returns true if the physical identifier and the logical cpu index * correspond to the same core/thread, false otherwise. */bool __weak arch_match_cpu_phys_id(int cpu, u64 phys_id){	return (u32)phys_id == cpu;} /** * Checks if the given "prop_name" property holds the physical id of the * core/thread corresponding to the logical cpu 'cpu'. If 'thread' is not * NULL, local thread number within the core is returned in it. */static bool __of_find_n_match_cpu_property(struct device_node *cpun,			const char *prop_name, int cpu, unsigned int *thread){	const __be32 *cell;	int ac, prop_len, tid;	u64 hwid; 	ac = of_n_addr_cells(cpun);	cell = of_get_property(cpun, prop_name, &prop_len);	if (!cell || !ac)		return false;	prop_len /= sizeof(*cell) * ac;	for (tid = 0; tid < prop_len; tid++) {		hwid = of_read_number(cell, ac);		if (arch_match_cpu_phys_id(cpu, hwid)) {			if (thread)				*thread = tid;			return true;		}		cell += ac;	}	return false;} /* * arch_find_n_match_cpu_physical_id - See if the given device node is * for the cpu corresponding to logical cpu 'cpu'.  Return true if so, * else false.  If 'thread' is non-NULL, the local thread number within the * core is returned in it. */bool __weak arch_find_n_match_cpu_physical_id(struct device_node *cpun,					      int cpu, unsigned int *thread){	/* Check for non-standard "ibm,ppc-interrupt-server#s" property	 * for thread ids on PowerPC. If it doesn't exist fallback to	 * standard "reg" property.	 */	if (IS_ENABLED(CONFIG_PPC) &&	    __of_find_n_match_cpu_property(cpun,					   "ibm,ppc-interrupt-server#s",					   cpu, thread))		return true; 	if (__of_find_n_match_cpu_property(cpun, "reg", cpu, thread))		return true; 	return false;} /** * of_get_cpu_node - Get device node associated with the given logical CPU * * @cpu: CPU number(logical index) for which device node is required * @thread: if not NULL, local thread number within the physical core is *          returned * * The main purpose of this function is to retrieve the device node for the * given logical CPU index. It should be used to initialize the of_node in * cpu device. Once of_node in cpu device is populated, all the further * references can use that instead. * * CPU logical to physical index mapping is architecture specific and is built * before booting secondary cores. This function uses arch_match_cpu_phys_id * which can be overridden by architecture specific implementation. * * Returns a node pointer for the logical cpu if found, else NULL. */struct device_node *of_get_cpu_node(int cpu, unsigned int *thread){	struct device_node *cpun; 	for_each_node_by_type(cpun, "cpu") {		if (arch_find_n_match_cpu_physical_id(cpun, cpu, thread))			return cpun;	}	return NULL;}EXPORT_SYMBOL(of_get_cpu_node); /** * __of_device_is_compatible() - Check if the node matches given constraints * @device: pointer to node * @compat: required compatible string, NULL or "" for any match * @type: required device_type value, NULL or "" for any match * @name: required node name, NULL or "" for any match * * Checks if the given @compat, @type and @name strings match the * properties of the given @device. A constraints can be skipped by * passing NULL or an empty string as the constraint. * * Returns 0 for no match, and a positive integer on match. The return * value is a relative score with larger values indicating better * matches. The score is weighted for the most specific compatible value * to get the highest score. Matching type is next, followed by matching * name. Practically speaking, this results in the following priority * order for matches: * * 1. specific compatible && type && name * 2. specific compatible && type * 3. specific compatible && name * 4. specific compatible * 5. general compatible && type && name * 6. general compatible && type * 7. general compatible && name * 8. general compatible * 9. type && name * 10. type * 11. name */static int __of_device_is_compatible(const struct device_node *device,				     const char *compat, const char *type, const char *name){	struct property *prop;	const char *cp;	int index = 0, score = 0; 	/* Compatible match has highest priority */	if (compat && compat[0]) {		prop = __of_find_property(device, "compatible", NULL);		for (cp = of_prop_next_string(prop, NULL); cp;		     cp = of_prop_next_string(prop, cp), index++) {			if (of_compat_cmp(cp, compat, strlen(compat)) == 0) {				score = INT_MAX/2 - (index << 2);				break;			}		}		if (!score)			return 0;	} 	/* Matching type is better than matching name */	if (type && type[0]) {		if (!device->type || of_node_cmp(type, device->type))			return 0;		score += 2;	} 	/* Matching name is a bit better than not */	if (name && name[0]) {		if (!device->name || of_node_cmp(name, device->name))			return 0;		score++;	} 	return score;} /** Checks if the given "compat" string matches one of the strings in * the device's "compatible" property */int of_device_is_compatible(const struct device_node *device,		const char *compat){	unsigned long flags;	int res; 	raw_spin_lock_irqsave(&devtree_lock, flags);	res = __of_device_is_compatible(device, compat, NULL, NULL);	raw_spin_unlock_irqrestore(&devtree_lock, flags);	return res;}EXPORT_SYMBOL(of_device_is_compatible); /** * of_machine_is_compatible - Test root of device tree for a given compatible value * @compat: compatible string to look for in root node's compatible property.

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