개념 설명 전체 · v6.6 / drivers/of/base.c

    1 // SPDX-License-Identifier: GPL-2.0+
    2 /*
    3  * Procedures for creating, accessing and interpreting the device tree.
    4  *
    5  * Paul Mackerras	August 1996.
    6  * Copyright (C) 1996-2005 Paul Mackerras.
    7  *
    8  *  Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
    9  *    {engebret|bergner}@us.ibm.com
   10  *
   11  *  Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
   12  *
   13  *  Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and
   14  *  Grant Likely.
   15  */
   16 
   17 #define pr_fmt(fmt)	"OF: " fmt
   18 
   19 #include <linux/console.h>
   20 #include <linux/ctype.h>
   21 #include <linux/cpu.h>
   22 #include <linux/module.h>
   23 #include <linux/of.h>
   24 #include <linux/of_device.h>
   25 #include <linux/of_graph.h>
   26 #include <linux/spinlock.h>
   27 #include <linux/slab.h>
   28 #include <linux/string.h>
   29 #include <linux/proc_fs.h>
   30 
   31 #include "of_private.h"
   32 
   33 LIST_HEAD(aliases_lookup);
   34 
   35 struct device_node *of_root;
   36 EXPORT_SYMBOL(of_root);
   37 struct device_node *of_chosen;
   38 EXPORT_SYMBOL(of_chosen);
   39 struct device_node *of_aliases;
   40 struct device_node *of_stdout;
   41 static const char *of_stdout_options;
   42 
   43 struct kset *of_kset;
   44 
   45 /*
   46  * Used to protect the of_aliases, to hold off addition of nodes to sysfs.
   47  * This mutex must be held whenever modifications are being made to the
   48  * device tree. The of_{attach,detach}_node() and
   49  * of_{add,remove,update}_property() helpers make sure this happens.
   50  */
   51 DEFINE_MUTEX(of_mutex);
   52 
   53 /* use when traversing tree through the child, sibling,
   54  * or parent members of struct device_node.
   55  */
   56 DEFINE_RAW_SPINLOCK(devtree_lock);
   57 
   58 bool of_node_name_eq(const struct device_node *np, const char *name)
   59 {
   60 	const char *node_name;
   61 	size_t len;
   62 
   63 	if (!np)
   64 		return false;
   65 
   66 	node_name = kbasename(np->full_name);
   67 	len = strchrnul(node_name, '@') - node_name;
   68 
   69 	return (strlen(name) == len) && (strncmp(node_name, name, len) == 0);
   70 }
   71 EXPORT_SYMBOL(of_node_name_eq);
   72 
   73 bool of_node_name_prefix(const struct device_node *np, const char *prefix)
   74 {
   75 	if (!np)
   76 		return false;
   77 
   78 	return strncmp(kbasename(np->full_name), prefix, strlen(prefix)) == 0;
   79 }
   80 EXPORT_SYMBOL(of_node_name_prefix);
   81 
   82 static bool __of_node_is_type(const struct device_node *np, const char *type)
   83 {
   84 	const char *match = __of_get_property(np, "device_type", NULL);
   85 
   86 	return np && match && type && !strcmp(match, type);
   87 }
   88 
   89 int of_bus_n_addr_cells(struct device_node *np)
   90 {
   91 	u32 cells;
   92 
   93 	for (; np; np = np->parent)
   94 		if (!of_property_read_u32(np, "#address-cells", &cells))
   95 			return cells;
   96 
   97 	/* No #address-cells property for the root node */
   98 	return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
   99 }
  100 
  101 int of_n_addr_cells(struct device_node *np)
  102 {
  103 	if (np->parent)
  104 		np = np->parent;
  105 
  106 	return of_bus_n_addr_cells(np);
  107 }
  108 EXPORT_SYMBOL(of_n_addr_cells);
  109 
  110 int of_bus_n_size_cells(struct device_node *np)
  111 {
  112 	u32 cells;
  113 
  114 	for (; np; np = np->parent)
  115 		if (!of_property_read_u32(np, "#size-cells", &cells))
  116 			return cells;
  117 
  118 	/* No #size-cells property for the root node */
  119 	return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
  120 }
  121 
  122 int of_n_size_cells(struct device_node *np)
  123 {
  124 	if (np->parent)
  125 		np = np->parent;
  126 
  127 	return of_bus_n_size_cells(np);
  128 }
  129 EXPORT_SYMBOL(of_n_size_cells);
  130 
  131 #ifdef CONFIG_NUMA
  132 int __weak of_node_to_nid(struct device_node *np)
  133 {
  134 	return NUMA_NO_NODE;
  135 }
  136 #endif
  137 
  138 #define OF_PHANDLE_CACHE_BITS	7
  139 #define OF_PHANDLE_CACHE_SZ	BIT(OF_PHANDLE_CACHE_BITS)
  140 
  141 static struct device_node *phandle_cache[OF_PHANDLE_CACHE_SZ];
  142 
  143 static u32 of_phandle_cache_hash(phandle handle)
  144 {
  145 	return hash_32(handle, OF_PHANDLE_CACHE_BITS);
  146 }
  147 
  148 /*
  149  * Caller must hold devtree_lock.
  150  */
  151 void __of_phandle_cache_inv_entry(phandle handle)
  152 {
  153 	u32 handle_hash;
  154 	struct device_node *np;
  155 
  156 	if (!handle)
  157 		return;
  158 
  159 	handle_hash = of_phandle_cache_hash(handle);
  160 
  161 	np = phandle_cache[handle_hash];
  162 	if (np && handle == np->phandle)
  163 		phandle_cache[handle_hash] = NULL;
  164 }
  165 
  166 void __init of_core_init(void)
  167 {
  168 	struct device_node *np;
  169 
  170 	of_platform_register_reconfig_notifier();
  171 
  172 	/* Create the kset, and register existing nodes */
  173 	mutex_lock(&of_mutex);
  174 	of_kset = kset_create_and_add("devicetree", NULL, firmware_kobj);
  175 	if (!of_kset) {
  176 		mutex_unlock(&of_mutex);
  177 		pr_err("failed to register existing nodes\n");
  178 		return;
  179 	}
  180 	for_each_of_allnodes(np) {
  181 		__of_attach_node_sysfs(np);
  182 		if (np->phandle && !phandle_cache[of_phandle_cache_hash(np->phandle)])
  183 			phandle_cache[of_phandle_cache_hash(np->phandle)] = np;
  184 	}
  185 	mutex_unlock(&of_mutex);
  186 
  187 	/* Symlink in /proc as required by userspace ABI */
  188 	if (of_root)
  189 		proc_symlink("device-tree", NULL, "/sys/firmware/devicetree/base");
  190 }
  191 
  192 static struct property *__of_find_property(const struct device_node *np,
  193 					   const char *name, int *lenp)
  194 {
  195 	struct property *pp;
  196 
  197 	if (!np)
  198 		return NULL;
  199 
  200 	for (pp = np->properties; pp; pp = pp->next) {
  201 		if (of_prop_cmp(pp->name, name) == 0) {
  202 			if (lenp)
  203 				*lenp = pp->length;
  204 			break;
  205 		}
  206 	}
  207 
  208 	return pp;
  209 }
  210 
  211 struct property *of_find_property(const struct device_node *np,
  212 				  const char *name,
  213 				  int *lenp)
  214 {
  215 	struct property *pp;
  216 	unsigned long flags;
  217 
  218 	raw_spin_lock_irqsave(&devtree_lock, flags);
  219 	pp = __of_find_property(np, name, lenp);
  220 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
  221 
  222 	return pp;
  223 }
  224 EXPORT_SYMBOL(of_find_property);
  225 
  226 struct device_node *__of_find_all_nodes(struct device_node *prev)
  227 {
  228 	struct device_node *np;
  229 	if (!prev) {
  230 		np = of_root;
  231 	} else if (prev->child) {
  232 		np = prev->child;
  233 	} else {
  234 		/* Walk back up looking for a sibling, or the end of the structure */
  235 		np = prev;
  236 		while (np->parent && !np->sibling)
  237 			np = np->parent;
  238 		np = np->sibling; /* Might be null at the end of the tree */
  239 	}
  240 	return np;
  241 }
  242 
  243 /**
  244  * of_find_all_nodes - Get next node in global list
  245  * @prev:	Previous node or NULL to start iteration
  246  *		of_node_put() will be called on it
  247  *
  248  * Return: A node pointer with refcount incremented, use
  249  * of_node_put() on it when done.
  250  */
  251 struct device_node *of_find_all_nodes(struct device_node *prev)
  252 {
  253 	struct device_node *np;
  254 	unsigned long flags;
  255 
  256 	raw_spin_lock_irqsave(&devtree_lock, flags);
  257 	np = __of_find_all_nodes(prev);
  258 	of_node_get(np);
  259 	of_node_put(prev);
  260 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
  261 	return np;
  262 }
  263 EXPORT_SYMBOL(of_find_all_nodes);
  264 
  265 /*
  266  * Find a property with a given name for a given node
  267  * and return the value.
  268  */
  269 const void *__of_get_property(const struct device_node *np,
  270 			      const char *name, int *lenp)
  271 {
  272 	struct property *pp = __of_find_property(np, name, lenp);
  273 
  274 	return pp ? pp->value : NULL;
  275 }
  276 
  277 /*
  278  * Find a property with a given name for a given node
  279  * and return the value.
  280  */
  281 const void *of_get_property(const struct device_node *np, const char *name,
  282 			    int *lenp)
  283 {
  284 	struct property *pp = of_find_property(np, name, lenp);
  285 
  286 	return pp ? pp->value : NULL;
  287 }
  288 EXPORT_SYMBOL(of_get_property);
  289 
  290 /**
  291  * __of_device_is_compatible() - Check if the node matches given constraints
  292  * @device: pointer to node
  293  * @compat: required compatible string, NULL or "" for any match
  294  * @type: required device_type value, NULL or "" for any match
  295  * @name: required node name, NULL or "" for any match
  296  *
  297  * Checks if the given @compat, @type and @name strings match the
  298  * properties of the given @device. A constraints can be skipped by
  299  * passing NULL or an empty string as the constraint.
  300  *
  301  * Returns 0 for no match, and a positive integer on match. The return
  302  * value is a relative score with larger values indicating better
  303  * matches. The score is weighted for the most specific compatible value
  304  * to get the highest score. Matching type is next, followed by matching
  305  * name. Practically speaking, this results in the following priority
  306  * order for matches:
  307  *
  308  * 1. specific compatible && type && name
  309  * 2. specific compatible && type
  310  * 3. specific compatible && name
  311  * 4. specific compatible
  312  * 5. general compatible && type && name
  313  * 6. general compatible && type
  314  * 7. general compatible && name
  315  * 8. general compatible
  316  * 9. type && name
  317  * 10. type
  318  * 11. name
  319  */
  320 static int __of_device_is_compatible(const struct device_node *device,
  321 				     const char *compat, const char *type, const char *name)
  322 {
  323 	struct property *prop;
  324 	const char *cp;
  325 	int index = 0, score = 0;
  326 
  327 	/* Compatible match has highest priority */
  328 	if (compat && compat[0]) {
  329 		prop = __of_find_property(device, "compatible", NULL);
  330 		for (cp = of_prop_next_string(prop, NULL); cp;
  331 		     cp = of_prop_next_string(prop, cp), index++) {
  332 			if (of_compat_cmp(cp, compat, strlen(compat)) == 0) {
  333 				score = INT_MAX/2 - (index << 2);
  334 				break;
  335 			}
  336 		}
  337 		if (!score)
  338 			return 0;
  339 	}
  340 
  341 	/* Matching type is better than matching name */
  342 	if (type && type[0]) {
  343 		if (!__of_node_is_type(device, type))
  344 			return 0;
  345 		score += 2;
  346 	}
  347 
  348 	/* Matching name is a bit better than not */
  349 	if (name && name[0]) {
  350 		if (!of_node_name_eq(device, name))
  351 			return 0;
  352 		score++;
  353 	}
  354 
  355 	return score;
  356 }
  357 
  358 /** Checks if the given "compat" string matches one of the strings in
  359  * the device's "compatible" property
  360  */
  361 int of_device_is_compatible(const struct device_node *device,
  362 		const char *compat)
  363 {
  364 	unsigned long flags;
  365 	int res;
  366 
  367 	raw_spin_lock_irqsave(&devtree_lock, flags);
  368 	res = __of_device_is_compatible(device, compat, NULL, NULL);
  369 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
  370 	return res;
  371 }
  372 EXPORT_SYMBOL(of_device_is_compatible);
  373 
  374 /** Checks if the device is compatible with any of the entries in
  375  *  a NULL terminated array of strings. Returns the best match
  376  *  score or 0.
  377  */
  378 int of_device_compatible_match(const struct device_node *device,
  379 			       const char *const *compat)
  380 {
  381 	unsigned int tmp, score = 0;
  382 
  383 	if (!compat)
  384 		return 0;
  385 
  386 	while (*compat) {
  387 		tmp = of_device_is_compatible(device, *compat);
  388 		if (tmp > score)
  389 			score = tmp;
  390 		compat++;
  391 	}
  392 
  393 	return score;
  394 }
  395 EXPORT_SYMBOL_GPL(of_device_compatible_match);
  396 
  397 /**
  398  * of_machine_is_compatible - Test root of device tree for a given compatible value
  399  * @compat: compatible string to look for in root node's compatible property.
  400  *
  401  * Return: A positive integer if the root node has the given value in its
  402  * compatible property.
  403  */
  404 int of_machine_is_compatible(const char *compat)
  405 {
  406 	struct device_node *root;
  407 	int rc = 0;
  408 
  409 	root = of_find_node_by_path("/");
  410 	if (root) {
  411 		rc = of_device_is_compatible(root, compat);
  412 		of_node_put(root);
  413 	}
  414 	return rc;
  415 }
  416 EXPORT_SYMBOL(of_machine_is_compatible);
  417 
  418 /**
  419  *  __of_device_is_available - check if a device is available for use
  420  *
  421  *  @device: Node to check for availability, with locks already held
  422  *
  423  *  Return: True if the status property is absent or set to "okay" or "ok",
  424  *  false otherwise
  425  */
  426 static bool __of_device_is_available(const struct device_node *device)
  427 {
  428 	const char *status;
  429 	int statlen;
  430 
  431 	if (!device)
  432 		return false;
  433 
  434 	status = __of_get_property(device, "status", &statlen);
  435 	if (status == NULL)
  436 		return true;
  437 
  438 	if (statlen > 0) {
  439 		if (!strcmp(status, "okay") || !strcmp(status, "ok"))
  440 			return true;
  441 	}
  442 
  443 	return false;
  444 }
  445 
  446 /**
  447  *  of_device_is_available - check if a device is available for use
  448  *
  449  *  @device: Node to check for availability
  450  *
  451  *  Return: True if the status property is absent or set to "okay" or "ok",
  452  *  false otherwise
  453  */
  454 bool of_device_is_available(const struct device_node *device)
  455 {
  456 	unsigned long flags;
  457 	bool res;
  458 
  459 	raw_spin_lock_irqsave(&devtree_lock, flags);
  460 	res = __of_device_is_available(device);
  461 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
  462 	return res;
  463 
  464 }
  465 EXPORT_SYMBOL(of_device_is_available);
  466 
  467 /**
  468  *  __of_device_is_fail - check if a device has status "fail" or "fail-..."
  469  *
  470  *  @device: Node to check status for, with locks already held
  471  *
  472  *  Return: True if the status property is set to "fail" or "fail-..." (for any
  473  *  error code suffix), false otherwise
  474  */
  475 static bool __of_device_is_fail(const struct device_node *device)
  476 {
  477 	const char *status;
  478 
  479 	if (!device)
  480 		return false;
  481 
  482 	status = __of_get_property(device, "status", NULL);
  483 	if (status == NULL)
  484 		return false;
  485 
  486 	return !strcmp(status, "fail") || !strncmp(status, "fail-", 5);
  487 }
  488 
  489 /**
  490  *  of_device_is_big_endian - check if a device has BE registers
  491  *
  492  *  @device: Node to check for endianness
  493  *
  494  *  Return: True if the device has a "big-endian" property, or if the kernel
  495  *  was compiled for BE *and* the device has a "native-endian" property.
  496  *  Returns false otherwise.
  497  *
  498  *  Callers would nominally use ioread32be/iowrite32be if
  499  *  of_device_is_big_endian() == true, or readl/writel otherwise.
  500  */
  501 bool of_device_is_big_endian(const struct device_node *device)
  502 {
  503 	if (of_property_read_bool(device, "big-endian"))
  504 		return true;
  505 	if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
  506 	    of_property_read_bool(device, "native-endian"))
  507 		return true;
  508 	return false;
  509 }
  510 EXPORT_SYMBOL(of_device_is_big_endian);
  511 
  512 /**
  513  * of_get_parent - Get a node's parent if any
  514  * @node:	Node to get parent
  515  *
  516  * Return: A node pointer with refcount incremented, use
  517  * of_node_put() on it when done.
  518  */
  519 struct device_node *of_get_parent(const struct device_node *node)
  520 {
  521 	struct device_node *np;
  522 	unsigned long flags;
  523 
  524 	if (!node)
  525 		return NULL;
  526 
  527 	raw_spin_lock_irqsave(&devtree_lock, flags);
  528 	np = of_node_get(node->parent);
  529 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
  530 	return np;
  531 }
  532 EXPORT_SYMBOL(of_get_parent);
  533 
  534 /**
  535  * of_get_next_parent - Iterate to a node's parent
  536  * @node:	Node to get parent of
  537  *
  538  * This is like of_get_parent() except that it drops the
  539  * refcount on the passed node, making it suitable for iterating
  540  * through a node's parents.
  541  *
  542  * Return: A node pointer with refcount incremented, use
  543  * of_node_put() on it when done.
  544  */
  545 struct device_node *of_get_next_parent(struct device_node *node)
  546 {
  547 	struct device_node *parent;
  548 	unsigned long flags;
  549 
  550 	if (!node)
  551 		return NULL;
  552 
  553 	raw_spin_lock_irqsave(&devtree_lock, flags);
  554 	parent = of_node_get(node->parent);
  555 	of_node_put(node);
  556 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
  557 	return parent;
  558 }
  559 EXPORT_SYMBOL(of_get_next_parent);
  560 
  561 static struct device_node *__of_get_next_child(const struct device_node *node,
  562 						struct device_node *prev)
  563 {
  564 	struct device_node *next;
  565 
  566 	if (!node)
  567 		return NULL;
  568 
  569 	next = prev ? prev->sibling : node->child;
  570 	of_node_get(next);
  571 	of_node_put(prev);
  572 	return next;
  573 }
  574 #define __for_each_child_of_node(parent, child) \
  575 	for (child = __of_get_next_child(parent, NULL); child != NULL; \
  576 	     child = __of_get_next_child(parent, child))
  577 
  578 /**
  579  * of_get_next_child - Iterate a node childs
  580  * @node:	parent node
  581  * @prev:	previous child of the parent node, or NULL to get first
  582  *
  583  * Return: A node pointer with refcount incremented, use of_node_put() on
  584  * it when done. Returns NULL when prev is the last child. Decrements the
  585  * refcount of prev.
  586  */
  587 struct device_node *of_get_next_child(const struct device_node *node,
  588 	struct device_node *prev)
  589 {
  590 	struct device_node *next;
  591 	unsigned long flags;
  592 
  593 	raw_spin_lock_irqsave(&devtree_lock, flags);
  594 	next = __of_get_next_child(node, prev);
  595 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
  596 	return next;
  597 }
  598 EXPORT_SYMBOL(of_get_next_child);
  599 
  600 /**
  601  * of_get_next_available_child - Find the next available child node
  602  * @node:	parent node
  603  * @prev:	previous child of the parent node, or NULL to get first
  604  *
  605  * This function is like of_get_next_child(), except that it
  606  * automatically skips any disabled nodes (i.e. status = "disabled").
  607  */
  608 struct device_node *of_get_next_available_child(const struct device_node *node,
  609 	struct device_node *prev)
  610 {
  611 	struct device_node *next;
  612 	unsigned long flags;
  613 
  614 	if (!node)
  615 		return NULL;
  616 
  617 	raw_spin_lock_irqsave(&devtree_lock, flags);
  618 	next = prev ? prev->sibling : node->child;
  619 	for (; next; next = next->sibling) {
  620 		if (!__of_device_is_available(next))
  621 			continue;
  622 		if (of_node_get(next))
  623 			break;
  624 	}
  625 	of_node_put(prev);
  626 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
  627 	return next;
  628 }
  629 EXPORT_SYMBOL(of_get_next_available_child);
  630 
  631 /**
  632  * of_get_next_cpu_node - Iterate on cpu nodes
  633  * @prev:	previous child of the /cpus node, or NULL to get first
  634  *
  635  * Unusable CPUs (those with the status property set to "fail" or "fail-...")
  636  * will be skipped.
  637  *
  638  * Return: A cpu node pointer with refcount incremented, use of_node_put()
  639  * on it when done. Returns NULL when prev is the last child. Decrements
  640  * the refcount of prev.
  641  */
  642 struct device_node *of_get_next_cpu_node(struct device_node *prev)
  643 {
  644 	struct device_node *next = NULL;
  645 	unsigned long flags;
  646 	struct device_node *node;
  647 
  648 	if (!prev)
  649 		node = of_find_node_by_path("/cpus");
  650 
  651 	raw_spin_lock_irqsave(&devtree_lock, flags);
  652 	if (prev)
  653 		next = prev->sibling;
  654 	else if (node) {
  655 		next = node->child;
  656 		of_node_put(node);
  657 	}
  658 	for (; next; next = next->sibling) {
  659 		if (__of_device_is_fail(next))
  660 			continue;
  661 		if (!(of_node_name_eq(next, "cpu") ||
  662 		      __of_node_is_type(next, "cpu")))
  663 			continue;
  664 		if (of_node_get(next))
  665 			break;
  666 	}
  667 	of_node_put(prev);
  668 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
  669 	return next;
  670 }
  671 EXPORT_SYMBOL(of_get_next_cpu_node);
  672 
  673 /**
  674  * of_get_compatible_child - Find compatible child node
  675  * @parent:	parent node
  676  * @compatible:	compatible string
  677  *
  678  * Lookup child node whose compatible property contains the given compatible
  679  * string.
  680  *
  681  * Return: a node pointer with refcount incremented, use of_node_put() on it
  682  * when done; or NULL if not found.
  683  */
  684 struct device_node *of_get_compatible_child(const struct device_node *parent,
  685 				const char *compatible)
  686 {
  687 	struct device_node *child;
  688 
  689 	for_each_child_of_node(parent, child) {
  690 		if (of_device_is_compatible(child, compatible))
  691 			break;
  692 	}
  693 
  694 	return child;
  695 }
  696 EXPORT_SYMBOL(of_get_compatible_child);
  697 
  698 /**
  699  * of_get_child_by_name - Find the child node by name for a given parent
  700  * @node:	parent node
  701  * @name:	child name to look for.
  702  *
  703  * This function looks for child node for given matching name
  704  *
  705  * Return: A node pointer if found, with refcount incremented, use
  706  * of_node_put() on it when done.
  707  * Returns NULL if node is not found.
  708  */
  709 struct device_node *of_get_child_by_name(const struct device_node *node,
  710 				const char *name)
  711 {
  712 	struct device_node *child;
  713 
  714 	for_each_child_of_node(node, child)
  715 		if (of_node_name_eq(child, name))
  716 			break;
  717 	return child;
  718 }
  719 EXPORT_SYMBOL(of_get_child_by_name);
  720 
  721 struct device_node *__of_find_node_by_path(struct device_node *parent,
  722 						const char *path)
  723 {
  724 	struct device_node *child;
  725 	int len;
  726 
  727 	len = strcspn(path, "/:");
  728 	if (!len)
  729 		return NULL;
  730 
  731 	__for_each_child_of_node(parent, child) {
  732 		const char *name = kbasename(child->full_name);
  733 		if (strncmp(path, name, len) == 0 && (strlen(name) == len))
  734 			return child;
  735 	}
  736 	return NULL;
  737 }
  738 
  739 struct device_node *__of_find_node_by_full_path(struct device_node *node,
  740 						const char *path)
  741 {
  742 	const char *separator = strchr(path, ':');
  743 
  744 	while (node && *path == '/') {
  745 		struct device_node *tmp = node;
  746 
  747 		path++; /* Increment past '/' delimiter */
  748 		node = __of_find_node_by_path(node, path);
  749 		of_node_put(tmp);
  750 		path = strchrnul(path, '/');
  751 		if (separator && separator < path)
  752 			break;
  753 	}
  754 	return node;
  755 }
  756 
  757 /**
  758  * of_find_node_opts_by_path - Find a node matching a full OF path
  759  * @path: Either the full path to match, or if the path does not
  760  *       start with '/', the name of a property of the /aliases
  761  *       node (an alias).  In the case of an alias, the node
  762  *       matching the alias' value will be returned.
  763  * @opts: Address of a pointer into which to store the start of
  764  *       an options string appended to the end of the path with
  765  *       a ':' separator.
  766  *
  767  * Valid paths:
  768  *  * /foo/bar	Full path
  769  *  * foo	Valid alias
  770  *  * foo/bar	Valid alias + relative path
  771  *
  772  * Return: A node pointer with refcount incremented, use
  773  * of_node_put() on it when done.
  774  */
  775 struct device_node *of_find_node_opts_by_path(const char *path, const char **opts)
  776 {
  777 	struct device_node *np = NULL;
  778 	struct property *pp;
  779 	unsigned long flags;
  780 	const char *separator = strchr(path, ':');
  781 
  782 	if (opts)
  783 		*opts = separator ? separator + 1 : NULL;
  784 
  785 	if (strcmp(path, "/") == 0)
  786 		return of_node_get(of_root);
  787 
  788 	/* The path could begin with an alias */
  789 	if (*path != '/') {
  790 		int len;
  791 		const char *p = separator;
  792 
  793 		if (!p)
  794 			p = strchrnul(path, '/');
  795 		len = p - path;
  796 
  797 		/* of_aliases must not be NULL */
  798 		if (!of_aliases)
  799 			return NULL;
  800 
  801 		for_each_property_of_node(of_aliases, pp) {
  802 			if (strlen(pp->name) == len && !strncmp(pp->name, path, len)) {
  803 				np = of_find_node_by_path(pp->value);
  804 				break;
  805 			}
  806 		}
  807 		if (!np)
  808 			return NULL;
  809 		path = p;
  810 	}
  811 
  812 	/* Step down the tree matching path components */
  813 	raw_spin_lock_irqsave(&devtree_lock, flags);
  814 	if (!np)
  815 		np = of_node_get(of_root);
  816 	np = __of_find_node_by_full_path(np, path);
  817 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
  818 	return np;
  819 }
  820 EXPORT_SYMBOL(of_find_node_opts_by_path);
  821 
  822 /**
  823  * of_find_node_by_name - Find a node by its "name" property
  824  * @from:	The node to start searching from or NULL; the node
  825  *		you pass will not be searched, only the next one
  826  *		will. Typically, you pass what the previous call
  827  *		returned. of_node_put() will be called on @from.
  828  * @name:	The name string to match against
  829  *
  830  * Return: A node pointer with refcount incremented, use
  831  * of_node_put() on it when done.
  832  */
  833 struct device_node *of_find_node_by_name(struct device_node *from,
  834 	const char *name)
  835 {
  836 	struct device_node *np;
  837 	unsigned long flags;
  838 
  839 	raw_spin_lock_irqsave(&devtree_lock, flags);
  840 	for_each_of_allnodes_from(from, np)
  841 		if (of_node_name_eq(np, name) && of_node_get(np))
  842 			break;
  843 	of_node_put(from);
  844 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
  845 	return np;
  846 }
  847 EXPORT_SYMBOL(of_find_node_by_name);
  848 
  849 /**
  850  * of_find_node_by_type - Find a node by its "device_type" property
  851  * @from:	The node to start searching from, or NULL to start searching
  852  *		the entire device tree. The node you pass will not be
  853  *		searched, only the next one will; typically, you pass
  854  *		what the previous call returned. of_node_put() will be
  855  *		called on from for you.
  856  * @type:	The type string to match against
  857  *
  858  * Return: A node pointer with refcount incremented, use
  859  * of_node_put() on it when done.
  860  */
  861 struct device_node *of_find_node_by_type(struct device_node *from,
  862 	const char *type)
  863 {
  864 	struct device_node *np;
  865 	unsigned long flags;
  866 
  867 	raw_spin_lock_irqsave(&devtree_lock, flags);
  868 	for_each_of_allnodes_from(from, np)
  869 		if (__of_node_is_type(np, type) && of_node_get(np))
  870 			break;
  871 	of_node_put(from);
  872 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
  873 	return np;
  874 }
  875 EXPORT_SYMBOL(of_find_node_by_type);
  876 
  877 /**
  878  * of_find_compatible_node - Find a node based on type and one of the
  879  *                                tokens in its "compatible" property
  880  * @from:	The node to start searching from or NULL, the node
  881  *		you pass will not be searched, only the next one
  882  *		will; typically, you pass what the previous call
  883  *		returned. of_node_put() will be called on it
  884  * @type:	The type string to match "device_type" or NULL to ignore
  885  * @compatible:	The string to match to one of the tokens in the device
  886  *		"compatible" list.
  887  *
  888  * Return: A node pointer with refcount incremented, use
  889  * of_node_put() on it when done.
  890  */
  891 struct device_node *of_find_compatible_node(struct device_node *from,
  892 	const char *type, const char *compatible)
  893 {
  894 	struct device_node *np;
  895 	unsigned long flags;
  896 
  897 	raw_spin_lock_irqsave(&devtree_lock, flags);
  898 	for_each_of_allnodes_from(from, np)
  899 		if (__of_device_is_compatible(np, compatible, type, NULL) &&
  900 		    of_node_get(np))
  901 			break;
  902 	of_node_put(from);
  903 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
  904 	return np;
  905 }
  906 EXPORT_SYMBOL(of_find_compatible_node);
  907 
  908 /**
  909  * of_find_node_with_property - Find a node which has a property with
  910  *                              the given name.
  911  * @from:	The node to start searching from or NULL, the node
  912  *		you pass will not be searched, only the next one
  913  *		will; typically, you pass what the previous call
  914  *		returned. of_node_put() will be called on it
  915  * @prop_name:	The name of the property to look for.
  916  *
  917  * Return: A node pointer with refcount incremented, use
  918  * of_node_put() on it when done.
  919  */
  920 struct device_node *of_find_node_with_property(struct device_node *from,
  921 	const char *prop_name)
  922 {
  923 	struct device_node *np;
  924 	struct property *pp;
  925 	unsigned long flags;
  926 
  927 	raw_spin_lock_irqsave(&devtree_lock, flags);
  928 	for_each_of_allnodes_from(from, np) {
  929 		for (pp = np->properties; pp; pp = pp->next) {
  930 			if (of_prop_cmp(pp->name, prop_name) == 0) {
  931 				of_node_get(np);
  932 				goto out;
  933 			}
  934 		}
  935 	}
  936 out:
  937 	of_node_put(from);
  938 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
  939 	return np;
  940 }
  941 EXPORT_SYMBOL(of_find_node_with_property);
  942 
  943 static
  944 const struct of_device_id *__of_match_node(const struct of_device_id *matches,
  945 					   const struct device_node *node)
  946 {
  947 	const struct of_device_id *best_match = NULL;
  948 	int score, best_score = 0;
  949 
  950 	if (!matches)
  951 		return NULL;
  952 
  953 	for (; matches->name[0] || matches->type[0] || matches->compatible[0]; matches++) {
  954 		score = __of_device_is_compatible(node, matches->compatible,
  955 						  matches->type, matches->name);
  956 		if (score > best_score) {
  957 			best_match = matches;
  958 			best_score = score;
  959 		}
  960 	}
  961 
  962 	return best_match;
  963 }
  964 
  965 /**
  966  * of_match_node - Tell if a device_node has a matching of_match structure
  967  * @matches:	array of of device match structures to search in
  968  * @node:	the of device structure to match against
  969  *
  970  * Low level utility function used by device matching.
  971  */
  972 const struct of_device_id *of_match_node(const struct of_device_id *matches,
  973 					 const struct device_node *node)
  974 {
  975 	const struct of_device_id *match;
  976 	unsigned long flags;
  977 
  978 	raw_spin_lock_irqsave(&devtree_lock, flags);
  979 	match = __of_match_node(matches, node);
  980 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
  981 	return match;
  982 }
  983 EXPORT_SYMBOL(of_match_node);
  984 
  985 /**
  986  * of_find_matching_node_and_match - Find a node based on an of_device_id
  987  *				     match table.
  988  * @from:	The node to start searching from or NULL, the node
  989  *		you pass will not be searched, only the next one
  990  *		will; typically, you pass what the previous call
  991  *		returned. of_node_put() will be called on it
  992  * @matches:	array of of device match structures to search in
  993  * @match:	Updated to point at the matches entry which matched
  994  *
  995  * Return: A node pointer with refcount incremented, use
  996  * of_node_put() on it when done.
  997  */
  998 struct device_node *of_find_matching_node_and_match(struct device_node *from,
  999 					const struct of_device_id *matches,
 1000 					const struct of_device_id **match)
 1001 {
 1002 	struct device_node *np;
 1003 	const struct of_device_id *m;
 1004 	unsigned long flags;
 1005 
 1006 	if (match)
 1007 		*match = NULL;
 1008 
 1009 	raw_spin_lock_irqsave(&devtree_lock, flags);
 1010 	for_each_of_allnodes_from(from, np) {
 1011 		m = __of_match_node(matches, np);
 1012 		if (m && of_node_get(np)) {
 1013 			if (match)
 1014 				*match = m;
 1015 			break;
 1016 		}
 1017 	}
 1018 	of_node_put(from);
 1019 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 1020 	return np;
 1021 }
 1022 EXPORT_SYMBOL(of_find_matching_node_and_match);
 1023 
 1024 /**
 1025  * of_alias_from_compatible - Lookup appropriate alias for a device node
 1026  *			      depending on compatible
 1027  * @node:	pointer to a device tree node
 1028  * @alias:	Pointer to buffer that alias value will be copied into
 1029  * @len:	Length of alias value
 1030  *
 1031  * Based on the value of the compatible property, this routine will attempt
 1032  * to choose an appropriate alias value for a particular device tree node.
 1033  * It does this by stripping the manufacturer prefix (as delimited by a ',')
 1034  * from the first entry in the compatible list property.
 1035  *
 1036  * Note: The matching on just the "product" side of the compatible is a relic
 1037  * from I2C and SPI. Please do not add any new user.
 1038  *
 1039  * Return: This routine returns 0 on success, <0 on failure.
 1040  */
 1041 int of_alias_from_compatible(const struct device_node *node, char *alias, int len)
 1042 {
 1043 	const char *compatible, *p;
 1044 	int cplen;
 1045 
 1046 	compatible = of_get_property(node, "compatible", &cplen);
 1047 	if (!compatible || strlen(compatible) > cplen)
 1048 		return -ENODEV;
 1049 	p = strchr(compatible, ',');
 1050 	strscpy(alias, p ? p + 1 : compatible, len);
 1051 	return 0;
 1052 }
 1053 EXPORT_SYMBOL_GPL(of_alias_from_compatible);
 1054 
 1055 /**
 1056  * of_find_node_by_phandle - Find a node given a phandle
 1057  * @handle:	phandle of the node to find
 1058  *
 1059  * Return: A node pointer with refcount incremented, use
 1060  * of_node_put() on it when done.
 1061  */
 1062 struct device_node *of_find_node_by_phandle(phandle handle)
 1063 {
 1064 	struct device_node *np = NULL;
 1065 	unsigned long flags;
 1066 	u32 handle_hash;
 1067 
 1068 	if (!handle)
 1069 		return NULL;
 1070 
 1071 	handle_hash = of_phandle_cache_hash(handle);
 1072 
 1073 	raw_spin_lock_irqsave(&devtree_lock, flags);
 1074 
 1075 	if (phandle_cache[handle_hash] &&
 1076 	    handle == phandle_cache[handle_hash]->phandle)
 1077 		np = phandle_cache[handle_hash];
 1078 
 1079 	if (!np) {
 1080 		for_each_of_allnodes(np)
 1081 			if (np->phandle == handle &&
 1082 			    !of_node_check_flag(np, OF_DETACHED)) {
 1083 				phandle_cache[handle_hash] = np;
 1084 				break;
 1085 			}
 1086 	}
 1087 
 1088 	of_node_get(np);
 1089 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 1090 	return np;
 1091 }
 1092 EXPORT_SYMBOL(of_find_node_by_phandle);
 1093 
 1094 void of_print_phandle_args(const char *msg, const struct of_phandle_args *args)
 1095 {
 1096 	int i;
 1097 	printk("%s %pOF", msg, args->np);
 1098 	for (i = 0; i < args->args_count; i++) {
 1099 		const char delim = i ? ',' : ':';
 1100 
 1101 		pr_cont("%c%08x", delim, args->args[i]);
 1102 	}
 1103 	pr_cont("\n");
 1104 }
 1105 
 1106 int of_phandle_iterator_init(struct of_phandle_iterator *it,
 1107 		const struct device_node *np,
 1108 		const char *list_name,
 1109 		const char *cells_name,
 1110 		int cell_count)
 1111 {
 1112 	const __be32 *list;
 1113 	int size;
 1114 
 1115 	memset(it, 0, sizeof(*it));
 1116 
 1117 	/*
 1118 	 * one of cell_count or cells_name must be provided to determine the
 1119 	 * argument length.
 1120 	 */
 1121 	if (cell_count < 0 && !cells_name)
 1122 		return -EINVAL;
 1123 
 1124 	list = of_get_property(np, list_name, &size);
 1125 	if (!list)
 1126 		return -ENOENT;
 1127 
 1128 	it->cells_name = cells_name;
 1129 	it->cell_count = cell_count;
 1130 	it->parent = np;
 1131 	it->list_end = list + size / sizeof(*list);
 1132 	it->phandle_end = list;
 1133 	it->cur = list;
 1134 
 1135 	return 0;
 1136 }
 1137 EXPORT_SYMBOL_GPL(of_phandle_iterator_init);
 1138 
 1139 int of_phandle_iterator_next(struct of_phandle_iterator *it)
 1140 {
 1141 	uint32_t count = 0;
 1142 
 1143 	if (it->node) {
 1144 		of_node_put(it->node);
 1145 		it->node = NULL;
 1146 	}
 1147 
 1148 	if (!it->cur || it->phandle_end >= it->list_end)
 1149 		return -ENOENT;
 1150 
 1151 	it->cur = it->phandle_end;
 1152 
 1153 	/* If phandle is 0, then it is an empty entry with no arguments. */
 1154 	it->phandle = be32_to_cpup(it->cur++);
 1155 
 1156 	if (it->phandle) {
 1157 
 1158 		/*
 1159 		 * Find the provider node and parse the #*-cells property to
 1160 		 * determine the argument length.
 1161 		 */
 1162 		it->node = of_find_node_by_phandle(it->phandle);
 1163 
 1164 		if (it->cells_name) {
 1165 			if (!it->node) {
 1166 				pr_err("%pOF: could not find phandle %d\n",
 1167 				       it->parent, it->phandle);
 1168 				goto err;
 1169 			}
 1170 
 1171 			if (of_property_read_u32(it->node, it->cells_name,
 1172 						 &count)) {
 1173 				/*
 1174 				 * If both cell_count and cells_name is given,
 1175 				 * fall back to cell_count in absence
 1176 				 * of the cells_name property
 1177 				 */
 1178 				if (it->cell_count >= 0) {
 1179 					count = it->cell_count;
 1180 				} else {
 1181 					pr_err("%pOF: could not get %s for %pOF\n",
 1182 					       it->parent,
 1183 					       it->cells_name,
 1184 					       it->node);
 1185 					goto err;
 1186 				}
 1187 			}
 1188 		} else {
 1189 			count = it->cell_count;
 1190 		}
 1191 
 1192 		/*
 1193 		 * Make sure that the arguments actually fit in the remaining
 1194 		 * property data length
 1195 		 */
 1196 		if (it->cur + count > it->list_end) {
 1197 			if (it->cells_name)
 1198 				pr_err("%pOF: %s = %d found %td\n",
 1199 					it->parent, it->cells_name,
 1200 					count, it->list_end - it->cur);
 1201 			else
 1202 				pr_err("%pOF: phandle %s needs %d, found %td\n",
 1203 					it->parent, of_node_full_name(it->node),
 1204 					count, it->list_end - it->cur);
 1205 			goto err;
 1206 		}
 1207 	}
 1208 
 1209 	it->phandle_end = it->cur + count;
 1210 	it->cur_count = count;
 1211 
 1212 	return 0;
 1213 
 1214 err:
 1215 	if (it->node) {
 1216 		of_node_put(it->node);
 1217 		it->node = NULL;
 1218 	}
 1219 
 1220 	return -EINVAL;
 1221 }
 1222 EXPORT_SYMBOL_GPL(of_phandle_iterator_next);
 1223 
 1224 int of_phandle_iterator_args(struct of_phandle_iterator *it,
 1225 			     uint32_t *args,
 1226 			     int size)
 1227 {
 1228 	int i, count;
 1229 
 1230 	count = it->cur_count;
 1231 
 1232 	if (WARN_ON(size < count))
 1233 		count = size;
 1234 
 1235 	for (i = 0; i < count; i++)
 1236 		args[i] = be32_to_cpup(it->cur++);
 1237 
 1238 	return count;
 1239 }
 1240 
 1241 int __of_parse_phandle_with_args(const struct device_node *np,
 1242 				 const char *list_name,
 1243 				 const char *cells_name,
 1244 				 int cell_count, int index,
 1245 				 struct of_phandle_args *out_args)
 1246 {
 1247 	struct of_phandle_iterator it;
 1248 	int rc, cur_index = 0;
 1249 
 1250 	if (index < 0)
 1251 		return -EINVAL;
 1252 
 1253 	/* Loop over the phandles until all the requested entry is found */
 1254 	of_for_each_phandle(&it, rc, np, list_name, cells_name, cell_count) {
 1255 		/*
 1256 		 * All of the error cases bail out of the loop, so at
 1257 		 * this point, the parsing is successful. If the requested
 1258 		 * index matches, then fill the out_args structure and return,
 1259 		 * or return -ENOENT for an empty entry.
 1260 		 */
 1261 		rc = -ENOENT;
 1262 		if (cur_index == index) {
 1263 			if (!it.phandle)
 1264 				goto err;
 1265 
 1266 			if (out_args) {
 1267 				int c;
 1268 
 1269 				c = of_phandle_iterator_args(&it,
 1270 							     out_args->args,
 1271 							     MAX_PHANDLE_ARGS);
 1272 				out_args->np = it.node;
 1273 				out_args->args_count = c;
 1274 			} else {
 1275 				of_node_put(it.node);
 1276 			}
 1277 
 1278 			/* Found it! return success */
 1279 			return 0;
 1280 		}
 1281 
 1282 		cur_index++;
 1283 	}
 1284 
 1285 	/*
 1286 	 * Unlock node before returning result; will be one of:
 1287 	 * -ENOENT : index is for empty phandle
 1288 	 * -EINVAL : parsing error on data
 1289 	 */
 1290 
 1291  err:
 1292 	of_node_put(it.node);
 1293 	return rc;
 1294 }
 1295 EXPORT_SYMBOL(__of_parse_phandle_with_args);
 1296 
 1297 /**
 1298  * of_parse_phandle_with_args_map() - Find a node pointed by phandle in a list and remap it
 1299  * @np:		pointer to a device tree node containing a list
 1300  * @list_name:	property name that contains a list
 1301  * @stem_name:	stem of property names that specify phandles' arguments count
 1302  * @index:	index of a phandle to parse out
 1303  * @out_args:	optional pointer to output arguments structure (will be filled)
 1304  *
 1305  * This function is useful to parse lists of phandles and their arguments.
 1306  * Returns 0 on success and fills out_args, on error returns appropriate errno
 1307  * value. The difference between this function and of_parse_phandle_with_args()
 1308  * is that this API remaps a phandle if the node the phandle points to has
 1309  * a <@stem_name>-map property.
 1310  *
 1311  * Caller is responsible to call of_node_put() on the returned out_args->np
 1312  * pointer.
 1313  *
 1314  * Example::
 1315  *
 1316  *  phandle1: node1 {
 1317  *  	#list-cells = <2>;
 1318  *  };
 1319  *
 1320  *  phandle2: node2 {
 1321  *  	#list-cells = <1>;
 1322  *  };
 1323  *
 1324  *  phandle3: node3 {
 1325  *  	#list-cells = <1>;
 1326  *  	list-map = <0 &phandle2 3>,
 1327  *  		   <1 &phandle2 2>,
 1328  *  		   <2 &phandle1 5 1>;
 1329  *  	list-map-mask = <0x3>;
 1330  *  };
 1331  *
 1332  *  node4 {
 1333  *  	list = <&phandle1 1 2 &phandle3 0>;
 1334  *  };
 1335  *
 1336  * To get a device_node of the ``node2`` node you may call this:
 1337  * of_parse_phandle_with_args(node4, "list", "list", 1, &args);
 1338  */
 1339 int of_parse_phandle_with_args_map(const struct device_node *np,
 1340 				   const char *list_name,
 1341 				   const char *stem_name,
 1342 				   int index, struct of_phandle_args *out_args)
 1343 {
 1344 	char *cells_name, *map_name = NULL, *mask_name = NULL;
 1345 	char *pass_name = NULL;
 1346 	struct device_node *cur, *new = NULL;
 1347 	const __be32 *map, *mask, *pass;
 1348 	static const __be32 dummy_mask[] = { [0 ... MAX_PHANDLE_ARGS] = ~0 };
 1349 	static const __be32 dummy_pass[] = { [0 ... MAX_PHANDLE_ARGS] = 0 };
 1350 	__be32 initial_match_array[MAX_PHANDLE_ARGS];
 1351 	const __be32 *match_array = initial_match_array;
 1352 	int i, ret, map_len, match;
 1353 	u32 list_size, new_size;
 1354 
 1355 	if (index < 0)
 1356 		return -EINVAL;
 1357 
 1358 	cells_name = kasprintf(GFP_KERNEL, "#%s-cells", stem_name);
 1359 	if (!cells_name)
 1360 		return -ENOMEM;
 1361 
 1362 	ret = -ENOMEM;
 1363 	map_name = kasprintf(GFP_KERNEL, "%s-map", stem_name);
 1364 	if (!map_name)
 1365 		goto free;
 1366 
 1367 	mask_name = kasprintf(GFP_KERNEL, "%s-map-mask", stem_name);
 1368 	if (!mask_name)
 1369 		goto free;
 1370 
 1371 	pass_name = kasprintf(GFP_KERNEL, "%s-map-pass-thru", stem_name);
 1372 	if (!pass_name)
 1373 		goto free;
 1374 
 1375 	ret = __of_parse_phandle_with_args(np, list_name, cells_name, -1, index,
 1376 					   out_args);
 1377 	if (ret)
 1378 		goto free;
 1379 
 1380 	/* Get the #<list>-cells property */
 1381 	cur = out_args->np;
 1382 	ret = of_property_read_u32(cur, cells_name, &list_size);
 1383 	if (ret < 0)
 1384 		goto put;
 1385 
 1386 	/* Precalculate the match array - this simplifies match loop */
 1387 	for (i = 0; i < list_size; i++)
 1388 		initial_match_array[i] = cpu_to_be32(out_args->args[i]);
 1389 
 1390 	ret = -EINVAL;
 1391 	while (cur) {
 1392 		/* Get the <list>-map property */
 1393 		map = of_get_property(cur, map_name, &map_len);
 1394 		if (!map) {
 1395 			ret = 0;
 1396 			goto free;
 1397 		}
 1398 		map_len /= sizeof(u32);
 1399 
 1400 		/* Get the <list>-map-mask property (optional) */
 1401 		mask = of_get_property(cur, mask_name, NULL);
 1402 		if (!mask)
 1403 			mask = dummy_mask;
 1404 		/* Iterate through <list>-map property */
 1405 		match = 0;
 1406 		while (map_len > (list_size + 1) && !match) {
 1407 			/* Compare specifiers */
 1408 			match = 1;
 1409 			for (i = 0; i < list_size; i++, map_len--)
 1410 				match &= !((match_array[i] ^ *map++) & mask[i]);
 1411 
 1412 			of_node_put(new);
 1413 			new = of_find_node_by_phandle(be32_to_cpup(map));
 1414 			map++;
 1415 			map_len--;
 1416 
 1417 			/* Check if not found */
 1418 			if (!new)
 1419 				goto put;
 1420 
 1421 			if (!of_device_is_available(new))
 1422 				match = 0;
 1423 
 1424 			ret = of_property_read_u32(new, cells_name, &new_size);
 1425 			if (ret)
 1426 				goto put;
 1427 
 1428 			/* Check for malformed properties */
 1429 			if (WARN_ON(new_size > MAX_PHANDLE_ARGS))
 1430 				goto put;
 1431 			if (map_len < new_size)
 1432 				goto put;
 1433 
 1434 			/* Move forward by new node's #<list>-cells amount */
 1435 			map += new_size;
 1436 			map_len -= new_size;
 1437 		}
 1438 		if (!match)
 1439 			goto put;
 1440 
 1441 		/* Get the <list>-map-pass-thru property (optional) */
 1442 		pass = of_get_property(cur, pass_name, NULL);
 1443 		if (!pass)
 1444 			pass = dummy_pass;
 1445 
 1446 		/*
 1447 		 * Successfully parsed a <list>-map translation; copy new
 1448 		 * specifier into the out_args structure, keeping the
 1449 		 * bits specified in <list>-map-pass-thru.
 1450 		 */
 1451 		match_array = map - new_size;
 1452 		for (i = 0; i < new_size; i++) {
 1453 			__be32 val = *(map - new_size + i);
 1454 
 1455 			if (i < list_size) {
 1456 				val &= ~pass[i];
 1457 				val |= cpu_to_be32(out_args->args[i]) & pass[i];
 1458 			}
 1459 
 1460 			out_args->args[i] = be32_to_cpu(val);
 1461 		}
 1462 		out_args->args_count = list_size = new_size;
 1463 		/* Iterate again with new provider */
 1464 		out_args->np = new;
 1465 		of_node_put(cur);
 1466 		cur = new;
 1467 	}
 1468 put:
 1469 	of_node_put(cur);
 1470 	of_node_put(new);
 1471 free:
 1472 	kfree(mask_name);
 1473 	kfree(map_name);
 1474 	kfree(cells_name);
 1475 	kfree(pass_name);
 1476 
 1477 	return ret;
 1478 }
 1479 EXPORT_SYMBOL(of_parse_phandle_with_args_map);
 1480 
 1481 /**
 1482  * of_count_phandle_with_args() - Find the number of phandles references in a property
 1483  * @np:		pointer to a device tree node containing a list
 1484  * @list_name:	property name that contains a list
 1485  * @cells_name:	property name that specifies phandles' arguments count
 1486  *
 1487  * Return: The number of phandle + argument tuples within a property. It
 1488  * is a typical pattern to encode a list of phandle and variable
 1489  * arguments into a single property. The number of arguments is encoded
 1490  * by a property in the phandle-target node. For example, a gpios
 1491  * property would contain a list of GPIO specifies consisting of a
 1492  * phandle and 1 or more arguments. The number of arguments are
 1493  * determined by the #gpio-cells property in the node pointed to by the
 1494  * phandle.
 1495  */
 1496 int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
 1497 				const char *cells_name)
 1498 {
 1499 	struct of_phandle_iterator it;
 1500 	int rc, cur_index = 0;
 1501 
 1502 	/*
 1503 	 * If cells_name is NULL we assume a cell count of 0. This makes
 1504 	 * counting the phandles trivial as each 32bit word in the list is a
 1505 	 * phandle and no arguments are to consider. So we don't iterate through
 1506 	 * the list but just use the length to determine the phandle count.
 1507 	 */
 1508 	if (!cells_name) {
 1509 		const __be32 *list;
 1510 		int size;
 1511 
 1512 		list = of_get_property(np, list_name, &size);
 1513 		if (!list)
 1514 			return -ENOENT;
 1515 
 1516 		return size / sizeof(*list);
 1517 	}
 1518 
 1519 	rc = of_phandle_iterator_init(&it, np, list_name, cells_name, -1);
 1520 	if (rc)
 1521 		return rc;
 1522 
 1523 	while ((rc = of_phandle_iterator_next(&it)) == 0)
 1524 		cur_index += 1;
 1525 
 1526 	if (rc != -ENOENT)
 1527 		return rc;
 1528 
 1529 	return cur_index;
 1530 }
 1531 EXPORT_SYMBOL(of_count_phandle_with_args);
 1532 
 1533 static struct property *__of_remove_property_from_list(struct property **list, struct property *prop)
 1534 {
 1535 	struct property **next;
 1536 
 1537 	for (next = list; *next; next = &(*next)->next) {
 1538 		if (*next == prop) {
 1539 			*next = prop->next;
 1540 			prop->next = NULL;
 1541 			return prop;
 1542 		}
 1543 	}
 1544 	return NULL;
 1545 }
 1546 
 1547 /**
 1548  * __of_add_property - Add a property to a node without lock operations
 1549  * @np:		Caller's Device Node
 1550  * @prop:	Property to add
 1551  */
 1552 int __of_add_property(struct device_node *np, struct property *prop)
 1553 {
 1554 	int rc = 0;
 1555 	unsigned long flags;
 1556 	struct property **next;
 1557 
 1558 	raw_spin_lock_irqsave(&devtree_lock, flags);
 1559 
 1560 	__of_remove_property_from_list(&np->deadprops, prop);
 1561 
 1562 	prop->next = NULL;
 1563 	next = &np->properties;
 1564 	while (*next) {
 1565 		if (strcmp(prop->name, (*next)->name) == 0) {
 1566 			/* duplicate ! don't insert it */
 1567 			rc = -EEXIST;
 1568 			goto out_unlock;
 1569 		}
 1570 		next = &(*next)->next;
 1571 	}
 1572 	*next = prop;
 1573 
 1574 out_unlock:
 1575 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 1576 	if (rc)
 1577 		return rc;
 1578 
 1579 	__of_add_property_sysfs(np, prop);
 1580 	return 0;
 1581 }
 1582 
 1583 /**
 1584  * of_add_property - Add a property to a node
 1585  * @np:		Caller's Device Node
 1586  * @prop:	Property to add
 1587  */
 1588 int of_add_property(struct device_node *np, struct property *prop)
 1589 {
 1590 	int rc;
 1591 
 1592 	mutex_lock(&of_mutex);
 1593 	rc = __of_add_property(np, prop);
 1594 	mutex_unlock(&of_mutex);
 1595 
 1596 	if (!rc)
 1597 		of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop, NULL);
 1598 
 1599 	return rc;
 1600 }
 1601 EXPORT_SYMBOL_GPL(of_add_property);
 1602 
 1603 int __of_remove_property(struct device_node *np, struct property *prop)
 1604 {
 1605 	unsigned long flags;
 1606 	int rc = -ENODEV;
 1607 
 1608 	raw_spin_lock_irqsave(&devtree_lock, flags);
 1609 
 1610 	if (__of_remove_property_from_list(&np->properties, prop)) {
 1611 		/* Found the property, add it to deadprops list */
 1612 		prop->next = np->deadprops;
 1613 		np->deadprops = prop;
 1614 		rc = 0;
 1615 	}
 1616 
 1617 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 1618 	if (rc)
 1619 		return rc;
 1620 
 1621 	__of_remove_property_sysfs(np, prop);
 1622 	return 0;
 1623 }
 1624 
 1625 /**
 1626  * of_remove_property - Remove a property from a node.
 1627  * @np:		Caller's Device Node
 1628  * @prop:	Property to remove
 1629  *
 1630  * Note that we don't actually remove it, since we have given out
 1631  * who-knows-how-many pointers to the data using get-property.
 1632  * Instead we just move the property to the "dead properties"
 1633  * list, so it won't be found any more.
 1634  */
 1635 int of_remove_property(struct device_node *np, struct property *prop)
 1636 {
 1637 	int rc;
 1638 
 1639 	if (!prop)
 1640 		return -ENODEV;
 1641 
 1642 	mutex_lock(&of_mutex);
 1643 	rc = __of_remove_property(np, prop);
 1644 	mutex_unlock(&of_mutex);
 1645 
 1646 	if (!rc)
 1647 		of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop, NULL);
 1648 
 1649 	return rc;
 1650 }
 1651 EXPORT_SYMBOL_GPL(of_remove_property);
 1652 
 1653 int __of_update_property(struct device_node *np, struct property *newprop,
 1654 		struct property **oldpropp)
 1655 {
 1656 	struct property **next, *oldprop;
 1657 	unsigned long flags;
 1658 
 1659 	raw_spin_lock_irqsave(&devtree_lock, flags);
 1660 
 1661 	__of_remove_property_from_list(&np->deadprops, newprop);
 1662 
 1663 	for (next = &np->properties; *next; next = &(*next)->next) {
 1664 		if (of_prop_cmp((*next)->name, newprop->name) == 0)
 1665 			break;
 1666 	}
 1667 	*oldpropp = oldprop = *next;
 1668 
 1669 	if (oldprop) {
 1670 		/* replace the node */
 1671 		newprop->next = oldprop->next;
 1672 		*next = newprop;
 1673 		oldprop->next = np->deadprops;
 1674 		np->deadprops = oldprop;
 1675 	} else {
 1676 		/* new node */
 1677 		newprop->next = NULL;
 1678 		*next = newprop;
 1679 	}
 1680 
 1681 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 1682 
 1683 	__of_update_property_sysfs(np, newprop, oldprop);
 1684 
 1685 	return 0;
 1686 }
 1687 
 1688 /*
 1689  * of_update_property - Update a property in a node, if the property does
 1690  * not exist, add it.
 1691  *
 1692  * Note that we don't actually remove it, since we have given out
 1693  * who-knows-how-many pointers to the data using get-property.
 1694  * Instead we just move the property to the "dead properties" list,
 1695  * and add the new property to the property list
 1696  */
 1697 int of_update_property(struct device_node *np, struct property *newprop)
 1698 {
 1699 	struct property *oldprop;
 1700 	int rc;
 1701 
 1702 	if (!newprop->name)
 1703 		return -EINVAL;
 1704 
 1705 	mutex_lock(&of_mutex);
 1706 	rc = __of_update_property(np, newprop, &oldprop);
 1707 	mutex_unlock(&of_mutex);
 1708 
 1709 	if (!rc)
 1710 		of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop, oldprop);
 1711 
 1712 	return rc;
 1713 }
 1714 
 1715 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
 1716 			 int id, const char *stem, int stem_len)
 1717 {
 1718 	ap->np = np;
 1719 	ap->id = id;
 1720 	strscpy(ap->stem, stem, stem_len + 1);
 1721 	list_add_tail(&ap->link, &aliases_lookup);
 1722 	pr_debug("adding DT alias:%s: stem=%s id=%i node=%pOF\n",
 1723 		 ap->alias, ap->stem, ap->id, np);
 1724 }
 1725 
 1726 /**
 1727  * of_alias_scan - Scan all properties of the 'aliases' node
 1728  * @dt_alloc:	An allocator that provides a virtual address to memory
 1729  *		for storing the resulting tree
 1730  *
 1731  * The function scans all the properties of the 'aliases' node and populates
 1732  * the global lookup table with the properties.  It returns the
 1733  * number of alias properties found, or an error code in case of failure.
 1734  */
 1735 void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
 1736 {
 1737 	struct property *pp;
 1738 
 1739 	of_aliases = of_find_node_by_path("/aliases");
 1740 	of_chosen = of_find_node_by_path("/chosen");
 1741 	if (of_chosen == NULL)
 1742 		of_chosen = of_find_node_by_path("/chosen@0");
 1743 
 1744 	if (of_chosen) {
 1745 		/* linux,stdout-path and /aliases/stdout are for legacy compatibility */
 1746 		const char *name = NULL;
 1747 
 1748 		if (of_property_read_string(of_chosen, "stdout-path", &name))
 1749 			of_property_read_string(of_chosen, "linux,stdout-path",
 1750 						&name);
 1751 		if (IS_ENABLED(CONFIG_PPC) && !name)
 1752 			of_property_read_string(of_aliases, "stdout", &name);
 1753 		if (name)
 1754 			of_stdout = of_find_node_opts_by_path(name, &of_stdout_options);
 1755 		if (of_stdout)
 1756 			of_stdout->fwnode.flags |= FWNODE_FLAG_BEST_EFFORT;
 1757 	}
 1758 
 1759 	if (!of_aliases)
 1760 		return;
 1761 
 1762 	for_each_property_of_node(of_aliases, pp) {
 1763 		const char *start = pp->name;
 1764 		const char *end = start + strlen(start);
 1765 		struct device_node *np;
 1766 		struct alias_prop *ap;
 1767 		int id, len;
 1768 
 1769 		/* Skip those we do not want to proceed */
 1770 		if (!strcmp(pp->name, "name") ||
 1771 		    !strcmp(pp->name, "phandle") ||
 1772 		    !strcmp(pp->name, "linux,phandle"))
 1773 			continue;
 1774 
 1775 		np = of_find_node_by_path(pp->value);
 1776 		if (!np)
 1777 			continue;
 1778 
 1779 		/* walk the alias backwards to extract the id and work out
 1780 		 * the 'stem' string */
 1781 		while (isdigit(*(end-1)) && end > start)
 1782 			end--;
 1783 		len = end - start;
 1784 
 1785 		if (kstrtoint(end, 10, &id) < 0)
 1786 			continue;
 1787 
 1788 		/* Allocate an alias_prop with enough space for the stem */
 1789 		ap = dt_alloc(sizeof(*ap) + len + 1, __alignof__(*ap));
 1790 		if (!ap)
 1791 			continue;
 1792 		memset(ap, 0, sizeof(*ap) + len + 1);
 1793 		ap->alias = start;
 1794 		of_alias_add(ap, np, id, start, len);
 1795 	}
 1796 }
 1797 
 1798 /**
 1799  * of_alias_get_id - Get alias id for the given device_node
 1800  * @np:		Pointer to the given device_node
 1801  * @stem:	Alias stem of the given device_node
 1802  *
 1803  * The function travels the lookup table to get the alias id for the given
 1804  * device_node and alias stem.
 1805  *
 1806  * Return: The alias id if found.
 1807  */
 1808 int of_alias_get_id(struct device_node *np, const char *stem)
 1809 {
 1810 	struct alias_prop *app;
 1811 	int id = -ENODEV;
 1812 
 1813 	mutex_lock(&of_mutex);
 1814 	list_for_each_entry(app, &aliases_lookup, link) {
 1815 		if (strcmp(app->stem, stem) != 0)
 1816 			continue;
 1817 
 1818 		if (np == app->np) {
 1819 			id = app->id;
 1820 			break;
 1821 		}
 1822 	}
 1823 	mutex_unlock(&of_mutex);
 1824 
 1825 	return id;
 1826 }
 1827 EXPORT_SYMBOL_GPL(of_alias_get_id);
 1828 
 1829 /**
 1830  * of_alias_get_highest_id - Get highest alias id for the given stem
 1831  * @stem:	Alias stem to be examined
 1832  *
 1833  * The function travels the lookup table to get the highest alias id for the
 1834  * given alias stem.  It returns the alias id if found.
 1835  */
 1836 int of_alias_get_highest_id(const char *stem)
 1837 {
 1838 	struct alias_prop *app;
 1839 	int id = -ENODEV;
 1840 
 1841 	mutex_lock(&of_mutex);
 1842 	list_for_each_entry(app, &aliases_lookup, link) {
 1843 		if (strcmp(app->stem, stem) != 0)
 1844 			continue;
 1845 
 1846 		if (app->id > id)
 1847 			id = app->id;
 1848 	}
 1849 	mutex_unlock(&of_mutex);
 1850 
 1851 	return id;
 1852 }
 1853 EXPORT_SYMBOL_GPL(of_alias_get_highest_id);
 1854 
 1855 /**
 1856  * of_console_check() - Test and setup console for DT setup
 1857  * @dn: Pointer to device node
 1858  * @name: Name to use for preferred console without index. ex. "ttyS"
 1859  * @index: Index to use for preferred console.
 1860  *
 1861  * Check if the given device node matches the stdout-path property in the
 1862  * /chosen node. If it does then register it as the preferred console.
 1863  *
 1864  * Return: TRUE if console successfully setup. Otherwise return FALSE.
 1865  */
 1866 bool of_console_check(struct device_node *dn, char *name, int index)
 1867 {
 1868 	if (!dn || dn != of_stdout || console_set_on_cmdline)
 1869 		return false;
 1870 
 1871 	/*
 1872 	 * XXX: cast `options' to char pointer to suppress complication
 1873 	 * warnings: printk, UART and console drivers expect char pointer.
 1874 	 */
 1875 	return !add_preferred_console(name, index, (char *)of_stdout_options);
 1876 }
 1877 EXPORT_SYMBOL_GPL(of_console_check);
 1878 
 1879 /**
 1880  * of_find_next_cache_node - Find a node's subsidiary cache
 1881  * @np:	node of type "cpu" or "cache"
 1882  *
 1883  * Return: A node pointer with refcount incremented, use
 1884  * of_node_put() on it when done.  Caller should hold a reference
 1885  * to np.
 1886  */
 1887 struct device_node *of_find_next_cache_node(const struct device_node *np)
 1888 {
 1889 	struct device_node *child, *cache_node;
 1890 
 1891 	cache_node = of_parse_phandle(np, "l2-cache", 0);
 1892 	if (!cache_node)
 1893 		cache_node = of_parse_phandle(np, "next-level-cache", 0);
 1894 
 1895 	if (cache_node)
 1896 		return cache_node;
 1897 
 1898 	/* OF on pmac has nodes instead of properties named "l2-cache"
 1899 	 * beneath CPU nodes.
 1900 	 */
 1901 	if (IS_ENABLED(CONFIG_PPC_PMAC) && of_node_is_type(np, "cpu"))
 1902 		for_each_child_of_node(np, child)
 1903 			if (of_node_is_type(child, "cache"))
 1904 				return child;
 1905 
 1906 	return NULL;
 1907 }
 1908 
 1909 /**
 1910  * of_find_last_cache_level - Find the level at which the last cache is
 1911  * 		present for the given logical cpu
 1912  *
 1913  * @cpu: cpu number(logical index) for which the last cache level is needed
 1914  *
 1915  * Return: The level at which the last cache is present. It is exactly
 1916  * same as  the total number of cache levels for the given logical cpu.
 1917  */
 1918 int of_find_last_cache_level(unsigned int cpu)
 1919 {
 1920 	u32 cache_level = 0;
 1921 	struct device_node *prev = NULL, *np = of_cpu_device_node_get(cpu);
 1922 
 1923 	while (np) {
 1924 		of_node_put(prev);
 1925 		prev = np;
 1926 		np = of_find_next_cache_node(np);
 1927 	}
 1928 
 1929 	of_property_read_u32(prev, "cache-level", &cache_level);
 1930 	of_node_put(prev);
 1931 
 1932 	return cache_level;
 1933 }
 1934 
 1935 /**
 1936  * of_map_id - Translate an ID through a downstream mapping.
 1937  * @np: root complex device node.
 1938  * @id: device ID to map.
 1939  * @map_name: property name of the map to use.
 1940  * @map_mask_name: optional property name of the mask to use.
 1941  * @target: optional pointer to a target device node.
 1942  * @id_out: optional pointer to receive the translated ID.
 1943  *
 1944  * Given a device ID, look up the appropriate implementation-defined
 1945  * platform ID and/or the target device which receives transactions on that
 1946  * ID, as per the "iommu-map" and "msi-map" bindings. Either of @target or
 1947  * @id_out may be NULL if only the other is required. If @target points to
 1948  * a non-NULL device node pointer, only entries targeting that node will be
 1949  * matched; if it points to a NULL value, it will receive the device node of
 1950  * the first matching target phandle, with a reference held.
 1951  *
 1952  * Return: 0 on success or a standard error code on failure.
 1953  */
 1954 int of_map_id(struct device_node *np, u32 id,
 1955 	       const char *map_name, const char *map_mask_name,
 1956 	       struct device_node **target, u32 *id_out)
 1957 {
 1958 	u32 map_mask, masked_id;
 1959 	int map_len;
 1960 	const __be32 *map = NULL;
 1961 
 1962 	if (!np || !map_name || (!target && !id_out))
 1963 		return -EINVAL;
 1964 
 1965 	map = of_get_property(np, map_name, &map_len);
 1966 	if (!map) {
 1967 		if (target)
 1968 			return -ENODEV;
 1969 		/* Otherwise, no map implies no translation */
 1970 		*id_out = id;
 1971 		return 0;
 1972 	}
 1973 
 1974 	if (!map_len || map_len % (4 * sizeof(*map))) {
 1975 		pr_err("%pOF: Error: Bad %s length: %d\n", np,
 1976 			map_name, map_len);
 1977 		return -EINVAL;
 1978 	}
 1979 
 1980 	/* The default is to select all bits. */
 1981 	map_mask = 0xffffffff;
 1982 
 1983 	/*
 1984 	 * Can be overridden by "{iommu,msi}-map-mask" property.
 1985 	 * If of_property_read_u32() fails, the default is used.
 1986 	 */
 1987 	if (map_mask_name)
 1988 		of_property_read_u32(np, map_mask_name, &map_mask);
 1989 
 1990 	masked_id = map_mask & id;
 1991 	for ( ; map_len > 0; map_len -= 4 * sizeof(*map), map += 4) {
 1992 		struct device_node *phandle_node;
 1993 		u32 id_base = be32_to_cpup(map + 0);
 1994 		u32 phandle = be32_to_cpup(map + 1);
 1995 		u32 out_base = be32_to_cpup(map + 2);
 1996 		u32 id_len = be32_to_cpup(map + 3);
 1997 
 1998 		if (id_base & ~map_mask) {
 1999 			pr_err("%pOF: Invalid %s translation - %s-mask (0x%x) ignores id-base (0x%x)\n",
 2000 				np, map_name, map_name,
 2001 				map_mask, id_base);
 2002 			return -EFAULT;
 2003 		}
 2004 
 2005 		if (masked_id < id_base || masked_id >= id_base + id_len)
 2006 			continue;
 2007 
 2008 		phandle_node = of_find_node_by_phandle(phandle);
 2009 		if (!phandle_node)
 2010 			return -ENODEV;
 2011 
 2012 		if (target) {
 2013 			if (*target)
 2014 				of_node_put(phandle_node);
 2015 			else
 2016 				*target = phandle_node;
 2017 
 2018 			if (*target != phandle_node)
 2019 				continue;
 2020 		}
 2021 
 2022 		if (id_out)
 2023 			*id_out = masked_id - id_base + out_base;
 2024 
 2025 		pr_debug("%pOF: %s, using mask %08x, id-base: %08x, out-base: %08x, length: %08x, id: %08x -> %08x\n",
 2026 			np, map_name, map_mask, id_base, out_base,
 2027 			id_len, id, masked_id - id_base + out_base);
 2028 		return 0;
 2029 	}
 2030 
 2031 	pr_info("%pOF: no %s translation for id 0x%x on %pOF\n", np, map_name,
 2032 		id, target && *target ? *target : NULL);
 2033 
 2034 	/* Bypasses translation */
 2035 	if (id_out)
 2036 		*id_out = id;
 2037 	return 0;
 2038 }
 2039 EXPORT_SYMBOL_GPL(of_map_id);