base.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * 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.
 */

#define pr_fmt(fmt)	"OF: " fmt

#include <linux/console.h>
#include <linux/ctype.h>
#include <linux/cpu.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.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)
{
	u32 cells;

	do {
		if (np->parent)
			np = np->parent;
		if (!of_property_read_u32(np, "#address-cells", &cells))
			return cells;
	} 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)
{
	u32 cells;

	do {
		if (np->parent)
			np = np->parent;
		if (!of_property_read_u32(np, "#size-cells", &cells))
			return cells;
	} 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_NUMA
int __weak of_node_to_nid(struct device_node *np)
{
	return NUMA_NO_NODE;
}
#endif

static struct device_node **phandle_cache;
static u32 phandle_cache_mask;

/*
 * Assumptions behind phandle_cache implementation:
 *   - phandle property values are in a contiguous range of 1..n
 *
 * If the assumptions do not hold, then
 *   - the phandle lookup overhead reduction provided by the cache
 *     will likely be less
 */
void of_populate_phandle_cache(void)
{
	unsigned long flags;
	u32 cache_entries;
	struct device_node *np;
	u32 phandles = 0;

	raw_spin_lock_irqsave(&devtree_lock, flags);

	kfree(phandle_cache);
	phandle_cache = NULL;

	for_each_of_allnodes(np)
		if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL)
			phandles++;

	cache_entries = roundup_pow_of_two(phandles);
	phandle_cache_mask = cache_entries - 1;

	phandle_cache = kcalloc(cache_entries, sizeof(*phandle_cache),
				GFP_ATOMIC);
	if (!phandle_cache)
		goto out;

	for_each_of_allnodes(np)
		if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL)
			phandle_cache[np->phandle & phandle_cache_mask] = np;

out:
	raw_spin_unlock_irqrestore(&devtree_lock, flags);
}

int of_free_phandle_cache(void)
{
	unsigned long flags;

	raw_spin_lock_irqsave(&devtree_lock, flags);

	kfree(phandle_cache);
	phandle_cache = NULL;

	raw_spin_unlock_irqrestore(&devtree_lock, flags);

	return 0;
}
#if !defined(CONFIG_MODULES)
late_initcall_sync(of_free_phandle_cache);
#endif

void __init of_core_init(void)
{
	struct device_node *np;

	of_populate_phandle_cache();

	/* 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("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;

	return __of_find_n_match_cpu_property(cpun, "reg", cpu, thread);
}

/**
 * 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 with refcount incremented, use
 * of_node_put() on it when done. Returns NULL if not found.
 */
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_cpu_node_to_id: Get the logical CPU number for a given device_node
 *
 * @cpu_node: Pointer to the device_node for CPU.
 *
 * Returns the logical CPU number of the given CPU device_node.
 * Returns -ENODEV if the CPU is not found.
 */
int of_cpu_node_to_id(struct device_node *cpu_node)
{
	int cpu;
	bool found = false;
	struct device_node *np;

	for_each_possible_cpu(cpu) {
		np = of_cpu_device_node_get(cpu);
		found = (cpu_node == np);
		of_node_put(np);
		if (found)
			return cpu;
	}

	return -ENODEV;
}
EXPORT_SYMBOL(of_cpu_node_to_id);

/**
 * __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);

/** Checks if the device is compatible with any of the entries in
 *  a NULL terminated array of strings. Returns the best match
 *  score or 0.
 */
int of_device_compatible_match(struct device_node *device,
			       const char *const *compat)
{
	unsigned int tmp, score = 0;

	if (!compat)
		return 0;

	while (*compat) {
		tmp = of_device_is_compatible(device, *compat);
		if (tmp > score)
			score = tmp;
		compat++;
	}

	return score;
}

/**
 * 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.
 *
 * Returns a positive integer if the root node has the given value in its
 * compatible property.
 */
int of_machine_is_compatible(const char *compat)
{
	struct device_node *root;
	int rc = 0;

	root = of_find_node_by_path("/");
	if (root) {
		rc = of_device_is_compatible(root, compat);
		of_node_put(root);
	}
	return rc;
}
EXPORT_SYMBOL(of_machine_is_compatible);

/**
 *  __of_device_is_available - check if a device is available for use
 *
 *  @device: Node to check for availability, with locks already held
 *
 *  Returns true if the status property is absent or set to "okay" or "ok",
 *  false otherwise
 */
static bool __of_device_is_available(const struct device_node *device)
{
	const char *status;
	int statlen;

	if (!device)
		return false;

	status = __of_get_property(device, "status", &statlen);
	if (status == NULL)
		return true;

	if (statlen > 0) {
		if (!strcmp(status, "okay") || !strcmp(status, "ok"))
			return true;
	}

	return false;
}

/**
 *  of_device_is_available - check if a device is available for use
 *
 *  @device: Node to check for availability
 *
 *  Returns true if the status property is absent or set to "okay" or "ok",
 *  false otherwise
 */
bool of_device_is_available(const struct device_node *device)
{
	unsigned long flags;
	bool res;

	raw_spin_lock_irqsave(&devtree_lock, flags);
	res = __of_device_is_available(device);
	raw_spin_unlock_irqrestore(&devtree_lock, flags);
	return res;

}
EXPORT_SYMBOL(of_device_is_available);

/**
 *  of_device_is_big_endian - check if a device has BE registers
 *
 *  @device: Node to check for endianness
 *
 *  Returns true if the device has a "big-endian" property, or if the kernel
 *  was compiled for BE *and* the device has a "native-endian" property.
 *  Returns false otherwise.
 *
 *  Callers would nominally use ioread32be/iowrite32be if
 *  of_device_is_big_endian() == true, or readl/writel otherwise.
 */
bool of_device_is_big_endian(const struct device_node *device)
{
	if (of_property_read_bool(device, "big-endian"))
		return true;
	if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
	    of_property_read_bool(device, "native-endian"))
		return true;
	return false;
}
EXPORT_SYMBOL(of_device_is_big_endian);

/**
 *	of_get_parent - Get a node's parent if any
 *	@node:	Node to get parent
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_get_parent(const struct device_node *node)
{
	struct device_node *np;
	unsigned long flags;

	if (!node)
		return NULL;

	raw_spin_lock_irqsave(&devtree_lock, flags);
	np = of_node_get(node->parent);
	raw_spin_unlock_irqrestore(&devtree_lock, flags);
	return np;
}
EXPORT_SYMBOL(of_get_parent);

/**
 *	of_get_next_parent - Iterate to a node's parent
 *	@node:	Node to get parent of
 *
 *	This is like of_get_parent() except that it drops the
 *	refcount on the passed node, making it suitable for iterating
 *	through a node's parents.
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_get_next_parent(struct device_node *node)
{
	struct device_node *parent;
	unsigned long flags;

	if (!node)
		return NULL;

	raw_spin_lock_irqsave(&devtree_lock, flags);
	parent = of_node_get(node->parent);
	of_node_put(node);
	raw_spin_unlock_irqrestore(&devtree_lock, flags);
	return parent;
}
EXPORT_SYMBOL(of_get_next_parent);

static struct device_node *__of_get_next_child(const struct device_node *node,
						struct device_node *prev)
{
	struct device_node *next;

	if (!node)
		return NULL;

	next = prev ? prev->sibling : node->child;
	for (; next; next = next->sibling)
		if (of_node_get(next))
			break;
	of_node_put(prev);
	return next;
}
#define __for_each_child_of_node(parent, child) \
	for (child = __of_get_next_child(parent, NULL); child != NULL; \
	     child = __of_get_next_child(parent, child))

/**
 *	of_get_next_child - Iterate a node childs
 *	@node:	parent node
 *	@prev:	previous child of the parent node, or NULL to get first
 *
 *	Returns a node pointer with refcount incremented, use of_node_put() on
 *	it when done. Returns NULL when prev is the last child. Decrements the
 *	refcount of prev.
 */
struct device_node *of_get_next_child(const struct device_node *node,
	struct device_node *prev)
{
	struct device_node *next;
	unsigned long flags;

	raw_spin_lock_irqsave(&devtree_lock, flags);
	next = __of_get_next_child(node, prev);
	raw_spin_unlock_irqrestore(&devtree_lock, flags);
	return next;
}
EXPORT_SYMBOL(of_get_next_child);

/**
 *	of_get_next_available_child - Find the next available child node
 *	@node:	parent node
 *	@prev:	previous child of the parent node, or NULL to get first
 *
 *      This function is like of_get_next_child(), except that it
 *      automatically skips any disabled nodes (i.e. status = "disabled").
 */
struct device_node *of_get_next_available_child(const struct device_node *node,
	struct device_node *prev)
{
	struct device_node *next;
	unsigned long flags;

	if (!node)
		return NULL;

	raw_spin_lock_irqsave(&devtree_lock, flags);
	next = prev ? prev->sibling : node->child;
	for (; next; next = next->sibling) {
		if (!__of_device_is_available(next))
			continue;
		if (of_node_get(next))
			break;
	}
	of_node_put(prev);
	raw_spin_unlock_irqrestore(&devtree_lock, flags);
	return next;
}
EXPORT_SYMBOL(of_get_next_available_child);

/**
 * of_get_compatible_child - Find compatible child node
 * @parent:	parent node
 * @compatible:	compatible string
 *
 * Lookup child node whose compatible property contains the given compatible
 * string.
 *
 * Returns a node pointer with refcount incremented, use of_node_put() on it
 * when done; or NULL if not found.
 */
struct device_node *of_get_compatible_child(const struct device_node *parent,
				const char *compatible)
{
	struct device_node *child;

	for_each_child_of_node(parent, child) {
		if (of_device_is_compatible(child, compatible))
			break;
	}

	return child;
}
EXPORT_SYMBOL(of_get_compatible_child);

/**
 *	of_get_child_by_name - Find the child node by name for a given parent
 *	@node:	parent node
 *	@name:	child name to look for.
 *
 *      This function looks for child node for given matching name
 *
 *	Returns a node pointer if found, with refcount incremented, use
 *	of_node_put() on it when done.
 *	Returns NULL if node is not found.
 */
struct device_node *of_get_child_by_name(const struct device_node *node,
				const char *name)
{
	struct device_node *child;

	for_each_child_of_node(node, child)
		if (child->name && (of_node_cmp(child->name, name) == 0))
			break;
	return child;
}
EXPORT_SYMBOL(of_get_child_by_name);

struct device_node *__of_find_node_by_path(struct device_node *parent,
						const char *path)
{
	struct device_node *child;
	int len;

	len = strcspn(path, "/:");
	if (!len)
		return NULL;

	__for_each_child_of_node(parent, child) {
		const char *name = kbasename(child->full_name);
		if (strncmp(path, name, len) == 0 && (strlen(name) == len))
			return child;
	}
	return NULL;
}

struct device_node *__of_find_node_by_full_path(struct device_node *node,
						const char *path)
{
	const char *separator = strchr(path, ':');

	while (node && *path == '/') {
		struct device_node *tmp = node;

		path++; /* Increment past '/' delimiter */
		node = __of_find_node_by_path(node, path);
		of_node_put(tmp);
		path = strchrnul(path, '/');
		if (separator && separator < path)
			break;
	}
	return node;
}

/**
 *	of_find_node_opts_by_path - Find a node matching a full OF path
 *	@path: Either the full path to match, or if the path does not
 *	       start with '/', the name of a property of the /aliases
 *	       node (an alias).  In the case of an alias, the node
 *	       matching the alias' value will be returned.
 *	@opts: Address of a pointer into which to store the start of
 *	       an options string appended to the end of the path with
 *	       a ':' separator.
 *
 *	Valid paths:
 *		/foo/bar	Full path
 *		foo		Valid alias
 *		foo/bar		Valid alias + relative path
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_opts_by_path(const char *path, const char **opts)
{
	struct device_node *np = NULL;
	struct property *pp;
	unsigned long flags;
	const char *separator = strchr(path, ':');

	if (opts)
		*opts = separator ? separator + 1 : NULL;

	if (strcmp(path, "/") == 0)
		return of_node_get(of_root);

	/* The path could begin with an alias */
	if (*path != '/') {
		int len;
		const char *p = separator;

		if (!p)
			p = strchrnul(path, '/');
		len = p - path;

		/* of_aliases must not be NULL */
		if (!of_aliases)
			return NULL;

		for_each_property_of_node(of_aliases, pp) {
			if (strlen(pp->name) == len && !strncmp(pp->name, path, len)) {
				np = of_find_node_by_path(pp->value);
				break;
			}
		}
		if (!np)
			return NULL;
		path = p;
	}

	/* Step down the tree matching path components */
	raw_spin_lock_irqsave(&devtree_lock, flags);
	if (!np)
		np = of_node_get(of_root);
	np = __of_find_node_by_full_path(np, path);
	raw_spin_unlock_irqrestore(&devtree_lock, flags);
	return np;
}
EXPORT_SYMBOL(of_find_node_opts_by_path);

/**
 *	of_find_node_by_name - Find a node by its "name" property
 *	@from:	The node to start searching from or NULL; the node
 *		you pass will not be searched, only the next one
 *		will. Typically, you pass what the previous call
 *		returned. of_node_put() will be called on @from.
 *	@name:	The name string to match against
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_by_name(struct device_node *from,
	const char *name)
{
	struct device_node *np;
	unsigned long flags;

	raw_spin_lock_irqsave(&devtree_lock, flags);
	for_each_of_allnodes_from(from, np)
		if (np->name && (of_node_cmp(np->name, name) == 0)
		    && of_node_get(np))
			break;
	of_node_put(from);
	raw_spin_unlock_irqrestore(&devtree_lock, flags);
	return np;
}
EXPORT_SYMBOL(of_find_node_by_name);

/**
 *	of_find_node_by_type - Find a node by its "device_type" property
 *	@from:	The node to start searching from, or NULL to start searching
 *		the entire device tree. The node you pass will not be
 *		searched, only the next one will; typically, you pass
 *		what the previous call returned. of_node_put() will be
 *		called on from for you.
 *	@type:	The type string to match against
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_by_type(struct device_node *from,
	const char *type)
{
	struct device_node *np;
	unsigned long flags;

	raw_spin_lock_irqsave(&devtree_lock, flags);
	for_each_of_allnodes_from(from, np)
		if (np->type && (of_node_cmp(np->type, type) == 0)
		    && of_node_get(np))
			break;
	of_node_put(from);
	raw_spin_unlock_irqrestore(&devtree_lock, flags);
	return np;
}
EXPORT_SYMBOL(of_find_node_by_type);

/**
 *	of_find_compatible_node - Find a node based on type and one of the
 *                                tokens in its "compatible" property
 *	@from:		The node to start searching from or NULL, the node
 *			you pass will not be searched, only the next one
 *			will; typically, you pass what the previous call
 *			returned. of_node_put() will be called on it
 *	@type:		The type string to match "device_type" or NULL to ignore
 *	@compatible:	The string to match to one of the tokens in the device
 *			"compatible" list.
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_compatible_node(struct device_node *from,
	const char *type, const char *compatible)
{
	struct device_node *np;
	unsigned long flags;

	raw_spin_lock_irqsave(&devtree_lock, flags);
	for_each_of_allnodes_from(from, np)
		if (__of_device_is_compatible(np, compatible, type, NULL) &&
		    of_node_get(np))
			break;
	of_node_put(from);
	raw_spin_unlock_irqrestore(&devtree_lock, flags);
	return np;
}
EXPORT_SYMBOL(of_find_compatible_node);

/**
 *	of_find_node_with_property - Find a node which has a property with
 *                                   the given name.
 *	@from:		The node to start searching from or NULL, the node
 *			you pass will not be searched, only the next one
 *			will; typically, you pass what the previous call
 *			returned. of_node_put() will be called on it
 *	@prop_name:	The name of the property to look for.
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_with_property(struct device_node *from,
	const char *prop_name)
{
	struct device_node *np;
	struct property *pp;
	unsigned long flags;

	raw_spin_lock_irqsave(&devtree_lock, flags);
	for_each_of_allnodes_from(from, np) {
		for (pp = np->properties; pp; pp = pp->next) {
			if (of_prop_cmp(pp->name, prop_name) == 0) {
				of_node_get(np);
				goto out;
			}
		}
	}
out:
	of_node_put(from);
	raw_spin_unlock_irqrestore(&devtree_lock, flags);
	return np;
}
EXPORT_SYMBOL(of_find_node_with_property);

static
const struct of_device_id *__of_match_node(const struct of_device_id *matches,
					   const struct device_node *node)
{
	const struct of_device_id *best_match = NULL;
	int score, best_score = 0;

	if (!matches)
		return NULL;

	for (; matches->name[0] || matches->type[0] || matches->compatible[0]; matches++) {
		score = __of_device_is_compatible(node, matches->compatible,
						  matches->type, matches->name);
		if (score > best_score) {
			best_match = matches;
			best_score = score;
		}
	}

	return best_match;
}

/**
 * of_match_node - Tell if a device_node has a matching of_match structure
 *	@matches:	array of of device match structures to search in
 *	@node:		the of device structure to match against
 *
 *	Low level utility function used by device matching.
 */
const struct of_device_id *of_match_node(const struct of_device_id *matches,
					 const struct device_node *node)
{
	const struct of_device_id *match;
	unsigned long flags;

	raw_spin_lock_irqsave(&devtree_lock, flags);
	match = __of_match_node(matches, node);
	raw_spin_unlock_irqrestore(&devtree_lock, flags);
	return match;
}
EXPORT_SYMBOL(of_match_node);

/**
 *	of_find_matching_node_and_match - Find a node based on an of_device_id
 *					  match table.
 *	@from:		The node to start searching from or NULL, the node
 *			you pass will not be searched, only the next one
 *			will; typically, you pass what the previous call
 *			returned. of_node_put() will be called on it
 *	@matches:	array of of device match structures to search in
 *	@match		Updated to point at the matches entry which matched
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_matching_node_and_match(struct device_node *from,
					const struct of_device_id *matches,
					const struct of_device_id **match)
{
	struct device_node *np;
	const struct of_device_id *m;
	unsigned long flags;

	if (match)
		*match = NULL;

	raw_spin_lock_irqsave(&devtree_lock, flags);
	for_each_of_allnodes_from(from, np) {
		m = __of_match_node(matches, np);
		if (m && of_node_get(np)) {
			if (match)
				*match = m;
			break;
		}
	}
	of_node_put(from);
	raw_spin_unlock_irqrestore(&devtree_lock, flags);
	return np;
}
EXPORT_SYMBOL(of_find_matching_node_and_match);

/**
 * of_modalias_node - Lookup appropriate modalias for a device node
 * @node:	pointer to a device tree node
 * @modalias:	Pointer to buffer that modalias value will be copied into
 * @len:	Length of modalias value
 *
 * Based on the value of the compatible property, this routine will attempt
 * to choose an appropriate modalias value for a particular device tree node.
 * It does this by stripping the manufacturer prefix (as delimited by a ',')
 * from the first entry in the compatible list property.
 *
 * This routine returns 0 on success, <0 on failure.
 */
int of_modalias_node(struct device_node *node, char *modalias, int len)
{
	const char *compatible, *p;
	int cplen;

	compatible = of_get_property(node, "compatible", &cplen);
	if (!compatible || strlen(compatible) > cplen)
		return -ENODEV;
	p = strchr(compatible, ',');
	strlcpy(modalias, p ? p + 1 : compatible, len);
	return 0;
}
EXPORT_SYMBOL_GPL(of_modalias_node);

/**
 * of_find_node_by_phandle - Find a node given a phandle
 * @handle:	phandle of the node to find
 *
 * Returns a node pointer with refcount incremented, use
 * of_node_put() on it when done.
 */
struct device_node *of_find_node_by_phandle(phandle handle)
{
	struct device_node *np = NULL;
	unsigned long flags;
	phandle masked_handle;

	if (!handle)
		return NULL;

	raw_spin_lock_irqsave(&devtree_lock, flags);

	masked_handle = handle & phandle_cache_mask;

	if (phandle_cache) {
		if (phandle_cache[masked_handle] &&
		    handle == phandle_cache[masked_handle]->phandle)
			np = phandle_cache[masked_handle];
	}

	if (!np) {
		for_each_of_allnodes(np)
			if (np->phandle == handle) {
				if (phandle_cache)
					phandle_cache[masked_handle] = np;
				break;
			}
	}

	of_node_get(np);
	raw_spin_unlock_irqrestore(&devtree_lock, flags);
	return np;
}
EXPORT_SYMBOL(of_find_node_by_phandle);

void of_print_phandle_args(const char *msg, const struct of_phandle_args *args)
{
	int i;
	printk("%s %pOF", msg, args->np);
	for (i = 0; i < args->args_count; i++) {
		const char delim = i ? ',' : ':';

		pr_cont("%c%08x", delim, args->args[i]);
	}
	pr_cont("\n");
}

int of_phandle_iterator_init(struct of_phandle_iterator *it,
		const struct device_node *np,
		const char *list_name,
		const char *cells_name,
		int cell_count)
{
	const __be32 *list;
	int size;

	memset(it, 0, sizeof(*it));

	list = of_get_property(np, list_name, &size);
	if (!list)
		return -ENOENT;

	it->cells_name = cells_name;
	it->cell_count = cell_count;
	it->parent = np;
	it->list_end = list + size / sizeof(*list);
	it->phandle_end = list;
	it->cur = list;

	return 0;
}
EXPORT_SYMBOL_GPL(of_phandle_iterator_init);

int of_phandle_iterator_next(struct of_phandle_iterator *it)
{
	uint32_t count = 0;

	if (it->node) {
		of_node_put(it->node);
		it->node = NULL;
	}

	if (!it->cur || it->phandle_end >= it->list_end)
		return -ENOENT;

	it->cur = it->phandle_end;

	/* If phandle is 0, then it is an empty entry with no arguments. */
	it->phandle = be32_to_cpup(it->cur++);

	if (it->phandle) {

		/*
		 * Find the provider node and parse the #*-cells property to
		 * determine the argument length.
		 */
		it->node = of_find_node_by_phandle(it->phandle);

		if (it->cells_name) {
			if (!it->node) {
				pr_err("%pOF: could not find phandle\n",
				       it->parent);
				goto err;
			}

			if (of_property_read_u32(it->node, it->cells_name,
						 &count)) {
				pr_err("%pOF: could not get %s for %pOF\n",
				       it->parent,
				       it->cells_name,
				       it->node);
				goto err;
			}
		} else {
			count = it->cell_count;
		}

		/*
		 * Make sure that the arguments actually fit in the remaining
		 * property data length
		 */
		if (it->cur + count > it->list_end) {
			pr_err("%pOF: arguments longer than property\n",
			       it->parent);
			goto err;
		}
	}

	it->phandle_end = it->cur + count;
	it->cur_count = count;

	return 0;

err:
	if (it->node) {
		of_node_put(it->node);
		it->node = NULL;
	}

	return -EINVAL;
}
EXPORT_SYMBOL_GPL(of_phandle_iterator_next);