xref: /openbmc/linux/drivers/of/base.c (revision 045f77ba)
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 struct device_node *of_aliases;
39 struct device_node *of_stdout;
40 static const char *of_stdout_options;
41 
42 struct kset *of_kset;
43 
44 /*
45  * Used to protect the of_aliases, to hold off addition of nodes to sysfs.
46  * This mutex must be held whenever modifications are being made to the
47  * device tree. The of_{attach,detach}_node() and
48  * of_{add,remove,update}_property() helpers make sure this happens.
49  */
50 DEFINE_MUTEX(of_mutex);
51 
52 /* use when traversing tree through the child, sibling,
53  * or parent members of struct device_node.
54  */
55 DEFINE_RAW_SPINLOCK(devtree_lock);
56 
57 int of_n_addr_cells(struct device_node *np)
58 {
59 	u32 cells;
60 
61 	do {
62 		if (np->parent)
63 			np = np->parent;
64 		if (!of_property_read_u32(np, "#address-cells", &cells))
65 			return cells;
66 	} while (np->parent);
67 	/* No #address-cells property for the root node */
68 	return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
69 }
70 EXPORT_SYMBOL(of_n_addr_cells);
71 
72 int of_n_size_cells(struct device_node *np)
73 {
74 	u32 cells;
75 
76 	do {
77 		if (np->parent)
78 			np = np->parent;
79 		if (!of_property_read_u32(np, "#size-cells", &cells))
80 			return cells;
81 	} while (np->parent);
82 	/* No #size-cells property for the root node */
83 	return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
84 }
85 EXPORT_SYMBOL(of_n_size_cells);
86 
87 #ifdef CONFIG_NUMA
88 int __weak of_node_to_nid(struct device_node *np)
89 {
90 	return NUMA_NO_NODE;
91 }
92 #endif
93 
94 static struct device_node **phandle_cache;
95 static u32 phandle_cache_mask;
96 
97 /*
98  * Assumptions behind phandle_cache implementation:
99  *   - phandle property values are in a contiguous range of 1..n
100  *
101  * If the assumptions do not hold, then
102  *   - the phandle lookup overhead reduction provided by the cache
103  *     will likely be less
104  */
105 void of_populate_phandle_cache(void)
106 {
107 	unsigned long flags;
108 	u32 cache_entries;
109 	struct device_node *np;
110 	u32 phandles = 0;
111 
112 	raw_spin_lock_irqsave(&devtree_lock, flags);
113 
114 	kfree(phandle_cache);
115 	phandle_cache = NULL;
116 
117 	for_each_of_allnodes(np)
118 		if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL)
119 			phandles++;
120 
121 	cache_entries = roundup_pow_of_two(phandles);
122 	phandle_cache_mask = cache_entries - 1;
123 
124 	phandle_cache = kcalloc(cache_entries, sizeof(*phandle_cache),
125 				GFP_ATOMIC);
126 	if (!phandle_cache)
127 		goto out;
128 
129 	for_each_of_allnodes(np)
130 		if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL)
131 			phandle_cache[np->phandle & phandle_cache_mask] = np;
132 
133 out:
134 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
135 }
136 
137 int of_free_phandle_cache(void)
138 {
139 	unsigned long flags;
140 
141 	raw_spin_lock_irqsave(&devtree_lock, flags);
142 
143 	kfree(phandle_cache);
144 	phandle_cache = NULL;
145 
146 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
147 
148 	return 0;
149 }
150 #if !defined(CONFIG_MODULES)
151 late_initcall_sync(of_free_phandle_cache);
152 #endif
153 
154 void __init of_core_init(void)
155 {
156 	struct device_node *np;
157 
158 	of_populate_phandle_cache();
159 
160 	/* Create the kset, and register existing nodes */
161 	mutex_lock(&of_mutex);
162 	of_kset = kset_create_and_add("devicetree", NULL, firmware_kobj);
163 	if (!of_kset) {
164 		mutex_unlock(&of_mutex);
165 		pr_err("failed to register existing nodes\n");
166 		return;
167 	}
168 	for_each_of_allnodes(np)
169 		__of_attach_node_sysfs(np);
170 	mutex_unlock(&of_mutex);
171 
172 	/* Symlink in /proc as required by userspace ABI */
173 	if (of_root)
174 		proc_symlink("device-tree", NULL, "/sys/firmware/devicetree/base");
175 }
176 
177 static struct property *__of_find_property(const struct device_node *np,
178 					   const char *name, int *lenp)
179 {
180 	struct property *pp;
181 
182 	if (!np)
183 		return NULL;
184 
185 	for (pp = np->properties; pp; pp = pp->next) {
186 		if (of_prop_cmp(pp->name, name) == 0) {
187 			if (lenp)
188 				*lenp = pp->length;
189 			break;
190 		}
191 	}
192 
193 	return pp;
194 }
195 
196 struct property *of_find_property(const struct device_node *np,
197 				  const char *name,
198 				  int *lenp)
199 {
200 	struct property *pp;
201 	unsigned long flags;
202 
203 	raw_spin_lock_irqsave(&devtree_lock, flags);
204 	pp = __of_find_property(np, name, lenp);
205 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
206 
207 	return pp;
208 }
209 EXPORT_SYMBOL(of_find_property);
210 
211 struct device_node *__of_find_all_nodes(struct device_node *prev)
212 {
213 	struct device_node *np;
214 	if (!prev) {
215 		np = of_root;
216 	} else if (prev->child) {
217 		np = prev->child;
218 	} else {
219 		/* Walk back up looking for a sibling, or the end of the structure */
220 		np = prev;
221 		while (np->parent && !np->sibling)
222 			np = np->parent;
223 		np = np->sibling; /* Might be null at the end of the tree */
224 	}
225 	return np;
226 }
227 
228 /**
229  * of_find_all_nodes - Get next node in global list
230  * @prev:	Previous node or NULL to start iteration
231  *		of_node_put() will be called on it
232  *
233  * Returns a node pointer with refcount incremented, use
234  * of_node_put() on it when done.
235  */
236 struct device_node *of_find_all_nodes(struct device_node *prev)
237 {
238 	struct device_node *np;
239 	unsigned long flags;
240 
241 	raw_spin_lock_irqsave(&devtree_lock, flags);
242 	np = __of_find_all_nodes(prev);
243 	of_node_get(np);
244 	of_node_put(prev);
245 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
246 	return np;
247 }
248 EXPORT_SYMBOL(of_find_all_nodes);
249 
250 /*
251  * Find a property with a given name for a given node
252  * and return the value.
253  */
254 const void *__of_get_property(const struct device_node *np,
255 			      const char *name, int *lenp)
256 {
257 	struct property *pp = __of_find_property(np, name, lenp);
258 
259 	return pp ? pp->value : NULL;
260 }
261 
262 /*
263  * Find a property with a given name for a given node
264  * and return the value.
265  */
266 const void *of_get_property(const struct device_node *np, const char *name,
267 			    int *lenp)
268 {
269 	struct property *pp = of_find_property(np, name, lenp);
270 
271 	return pp ? pp->value : NULL;
272 }
273 EXPORT_SYMBOL(of_get_property);
274 
275 /*
276  * arch_match_cpu_phys_id - Match the given logical CPU and physical id
277  *
278  * @cpu: logical cpu index of a core/thread
279  * @phys_id: physical identifier of a core/thread
280  *
281  * CPU logical to physical index mapping is architecture specific.
282  * However this __weak function provides a default match of physical
283  * id to logical cpu index. phys_id provided here is usually values read
284  * from the device tree which must match the hardware internal registers.
285  *
286  * Returns true if the physical identifier and the logical cpu index
287  * correspond to the same core/thread, false otherwise.
288  */
289 bool __weak arch_match_cpu_phys_id(int cpu, u64 phys_id)
290 {
291 	return (u32)phys_id == cpu;
292 }
293 
294 /**
295  * Checks if the given "prop_name" property holds the physical id of the
296  * core/thread corresponding to the logical cpu 'cpu'. If 'thread' is not
297  * NULL, local thread number within the core is returned in it.
298  */
299 static bool __of_find_n_match_cpu_property(struct device_node *cpun,
300 			const char *prop_name, int cpu, unsigned int *thread)
301 {
302 	const __be32 *cell;
303 	int ac, prop_len, tid;
304 	u64 hwid;
305 
306 	ac = of_n_addr_cells(cpun);
307 	cell = of_get_property(cpun, prop_name, &prop_len);
308 	if (!cell || !ac)
309 		return false;
310 	prop_len /= sizeof(*cell) * ac;
311 	for (tid = 0; tid < prop_len; tid++) {
312 		hwid = of_read_number(cell, ac);
313 		if (arch_match_cpu_phys_id(cpu, hwid)) {
314 			if (thread)
315 				*thread = tid;
316 			return true;
317 		}
318 		cell += ac;
319 	}
320 	return false;
321 }
322 
323 /*
324  * arch_find_n_match_cpu_physical_id - See if the given device node is
325  * for the cpu corresponding to logical cpu 'cpu'.  Return true if so,
326  * else false.  If 'thread' is non-NULL, the local thread number within the
327  * core is returned in it.
328  */
329 bool __weak arch_find_n_match_cpu_physical_id(struct device_node *cpun,
330 					      int cpu, unsigned int *thread)
331 {
332 	/* Check for non-standard "ibm,ppc-interrupt-server#s" property
333 	 * for thread ids on PowerPC. If it doesn't exist fallback to
334 	 * standard "reg" property.
335 	 */
336 	if (IS_ENABLED(CONFIG_PPC) &&
337 	    __of_find_n_match_cpu_property(cpun,
338 					   "ibm,ppc-interrupt-server#s",
339 					   cpu, thread))
340 		return true;
341 
342 	return __of_find_n_match_cpu_property(cpun, "reg", cpu, thread);
343 }
344 
345 /**
346  * of_get_cpu_node - Get device node associated with the given logical CPU
347  *
348  * @cpu: CPU number(logical index) for which device node is required
349  * @thread: if not NULL, local thread number within the physical core is
350  *          returned
351  *
352  * The main purpose of this function is to retrieve the device node for the
353  * given logical CPU index. It should be used to initialize the of_node in
354  * cpu device. Once of_node in cpu device is populated, all the further
355  * references can use that instead.
356  *
357  * CPU logical to physical index mapping is architecture specific and is built
358  * before booting secondary cores. This function uses arch_match_cpu_phys_id
359  * which can be overridden by architecture specific implementation.
360  *
361  * Returns a node pointer for the logical cpu with refcount incremented, use
362  * of_node_put() on it when done. Returns NULL if not found.
363  */
364 struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
365 {
366 	struct device_node *cpun;
367 
368 	for_each_node_by_type(cpun, "cpu") {
369 		if (arch_find_n_match_cpu_physical_id(cpun, cpu, thread))
370 			return cpun;
371 	}
372 	return NULL;
373 }
374 EXPORT_SYMBOL(of_get_cpu_node);
375 
376 /**
377  * of_cpu_node_to_id: Get the logical CPU number for a given device_node
378  *
379  * @cpu_node: Pointer to the device_node for CPU.
380  *
381  * Returns the logical CPU number of the given CPU device_node.
382  * Returns -ENODEV if the CPU is not found.
383  */
384 int of_cpu_node_to_id(struct device_node *cpu_node)
385 {
386 	int cpu;
387 	bool found = false;
388 	struct device_node *np;
389 
390 	for_each_possible_cpu(cpu) {
391 		np = of_cpu_device_node_get(cpu);
392 		found = (cpu_node == np);
393 		of_node_put(np);
394 		if (found)
395 			return cpu;
396 	}
397 
398 	return -ENODEV;
399 }
400 EXPORT_SYMBOL(of_cpu_node_to_id);
401 
402 /**
403  * __of_device_is_compatible() - Check if the node matches given constraints
404  * @device: pointer to node
405  * @compat: required compatible string, NULL or "" for any match
406  * @type: required device_type value, NULL or "" for any match
407  * @name: required node name, NULL or "" for any match
408  *
409  * Checks if the given @compat, @type and @name strings match the
410  * properties of the given @device. A constraints can be skipped by
411  * passing NULL or an empty string as the constraint.
412  *
413  * Returns 0 for no match, and a positive integer on match. The return
414  * value is a relative score with larger values indicating better
415  * matches. The score is weighted for the most specific compatible value
416  * to get the highest score. Matching type is next, followed by matching
417  * name. Practically speaking, this results in the following priority
418  * order for matches:
419  *
420  * 1. specific compatible && type && name
421  * 2. specific compatible && type
422  * 3. specific compatible && name
423  * 4. specific compatible
424  * 5. general compatible && type && name
425  * 6. general compatible && type
426  * 7. general compatible && name
427  * 8. general compatible
428  * 9. type && name
429  * 10. type
430  * 11. name
431  */
432 static int __of_device_is_compatible(const struct device_node *device,
433 				     const char *compat, const char *type, const char *name)
434 {
435 	struct property *prop;
436 	const char *cp;
437 	int index = 0, score = 0;
438 
439 	/* Compatible match has highest priority */
440 	if (compat && compat[0]) {
441 		prop = __of_find_property(device, "compatible", NULL);
442 		for (cp = of_prop_next_string(prop, NULL); cp;
443 		     cp = of_prop_next_string(prop, cp), index++) {
444 			if (of_compat_cmp(cp, compat, strlen(compat)) == 0) {
445 				score = INT_MAX/2 - (index << 2);
446 				break;
447 			}
448 		}
449 		if (!score)
450 			return 0;
451 	}
452 
453 	/* Matching type is better than matching name */
454 	if (type && type[0]) {
455 		if (!device->type || of_node_cmp(type, device->type))
456 			return 0;
457 		score += 2;
458 	}
459 
460 	/* Matching name is a bit better than not */
461 	if (name && name[0]) {
462 		if (!device->name || of_node_cmp(name, device->name))
463 			return 0;
464 		score++;
465 	}
466 
467 	return score;
468 }
469 
470 /** Checks if the given "compat" string matches one of the strings in
471  * the device's "compatible" property
472  */
473 int of_device_is_compatible(const struct device_node *device,
474 		const char *compat)
475 {
476 	unsigned long flags;
477 	int res;
478 
479 	raw_spin_lock_irqsave(&devtree_lock, flags);
480 	res = __of_device_is_compatible(device, compat, NULL, NULL);
481 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
482 	return res;
483 }
484 EXPORT_SYMBOL(of_device_is_compatible);
485 
486 /** Checks if the device is compatible with any of the entries in
487  *  a NULL terminated array of strings. Returns the best match
488  *  score or 0.
489  */
490 int of_device_compatible_match(struct device_node *device,
491 			       const char *const *compat)
492 {
493 	unsigned int tmp, score = 0;
494 
495 	if (!compat)
496 		return 0;
497 
498 	while (*compat) {
499 		tmp = of_device_is_compatible(device, *compat);
500 		if (tmp > score)
501 			score = tmp;
502 		compat++;
503 	}
504 
505 	return score;
506 }
507 
508 /**
509  * of_machine_is_compatible - Test root of device tree for a given compatible value
510  * @compat: compatible string to look for in root node's compatible property.
511  *
512  * Returns a positive integer if the root node has the given value in its
513  * compatible property.
514  */
515 int of_machine_is_compatible(const char *compat)
516 {
517 	struct device_node *root;
518 	int rc = 0;
519 
520 	root = of_find_node_by_path("/");
521 	if (root) {
522 		rc = of_device_is_compatible(root, compat);
523 		of_node_put(root);
524 	}
525 	return rc;
526 }
527 EXPORT_SYMBOL(of_machine_is_compatible);
528 
529 /**
530  *  __of_device_is_available - check if a device is available for use
531  *
532  *  @device: Node to check for availability, with locks already held
533  *
534  *  Returns true if the status property is absent or set to "okay" or "ok",
535  *  false otherwise
536  */
537 static bool __of_device_is_available(const struct device_node *device)
538 {
539 	const char *status;
540 	int statlen;
541 
542 	if (!device)
543 		return false;
544 
545 	status = __of_get_property(device, "status", &statlen);
546 	if (status == NULL)
547 		return true;
548 
549 	if (statlen > 0) {
550 		if (!strcmp(status, "okay") || !strcmp(status, "ok"))
551 			return true;
552 	}
553 
554 	return false;
555 }
556 
557 /**
558  *  of_device_is_available - check if a device is available for use
559  *
560  *  @device: Node to check for availability
561  *
562  *  Returns true if the status property is absent or set to "okay" or "ok",
563  *  false otherwise
564  */
565 bool of_device_is_available(const struct device_node *device)
566 {
567 	unsigned long flags;
568 	bool res;
569 
570 	raw_spin_lock_irqsave(&devtree_lock, flags);
571 	res = __of_device_is_available(device);
572 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
573 	return res;
574 
575 }
576 EXPORT_SYMBOL(of_device_is_available);
577 
578 /**
579  *  of_device_is_big_endian - check if a device has BE registers
580  *
581  *  @device: Node to check for endianness
582  *
583  *  Returns true if the device has a "big-endian" property, or if the kernel
584  *  was compiled for BE *and* the device has a "native-endian" property.
585  *  Returns false otherwise.
586  *
587  *  Callers would nominally use ioread32be/iowrite32be if
588  *  of_device_is_big_endian() == true, or readl/writel otherwise.
589  */
590 bool of_device_is_big_endian(const struct device_node *device)
591 {
592 	if (of_property_read_bool(device, "big-endian"))
593 		return true;
594 	if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
595 	    of_property_read_bool(device, "native-endian"))
596 		return true;
597 	return false;
598 }
599 EXPORT_SYMBOL(of_device_is_big_endian);
600 
601 /**
602  *	of_get_parent - Get a node's parent if any
603  *	@node:	Node to get parent
604  *
605  *	Returns a node pointer with refcount incremented, use
606  *	of_node_put() on it when done.
607  */
608 struct device_node *of_get_parent(const struct device_node *node)
609 {
610 	struct device_node *np;
611 	unsigned long flags;
612 
613 	if (!node)
614 		return NULL;
615 
616 	raw_spin_lock_irqsave(&devtree_lock, flags);
617 	np = of_node_get(node->parent);
618 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
619 	return np;
620 }
621 EXPORT_SYMBOL(of_get_parent);
622 
623 /**
624  *	of_get_next_parent - Iterate to a node's parent
625  *	@node:	Node to get parent of
626  *
627  *	This is like of_get_parent() except that it drops the
628  *	refcount on the passed node, making it suitable for iterating
629  *	through a node's parents.
630  *
631  *	Returns a node pointer with refcount incremented, use
632  *	of_node_put() on it when done.
633  */
634 struct device_node *of_get_next_parent(struct device_node *node)
635 {
636 	struct device_node *parent;
637 	unsigned long flags;
638 
639 	if (!node)
640 		return NULL;
641 
642 	raw_spin_lock_irqsave(&devtree_lock, flags);
643 	parent = of_node_get(node->parent);
644 	of_node_put(node);
645 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
646 	return parent;
647 }
648 EXPORT_SYMBOL(of_get_next_parent);
649 
650 static struct device_node *__of_get_next_child(const struct device_node *node,
651 						struct device_node *prev)
652 {
653 	struct device_node *next;
654 
655 	if (!node)
656 		return NULL;
657 
658 	next = prev ? prev->sibling : node->child;
659 	for (; next; next = next->sibling)
660 		if (of_node_get(next))
661 			break;
662 	of_node_put(prev);
663 	return next;
664 }
665 #define __for_each_child_of_node(parent, child) \
666 	for (child = __of_get_next_child(parent, NULL); child != NULL; \
667 	     child = __of_get_next_child(parent, child))
668 
669 /**
670  *	of_get_next_child - Iterate a node childs
671  *	@node:	parent node
672  *	@prev:	previous child of the parent node, or NULL to get first
673  *
674  *	Returns a node pointer with refcount incremented, use of_node_put() on
675  *	it when done. Returns NULL when prev is the last child. Decrements the
676  *	refcount of prev.
677  */
678 struct device_node *of_get_next_child(const struct device_node *node,
679 	struct device_node *prev)
680 {
681 	struct device_node *next;
682 	unsigned long flags;
683 
684 	raw_spin_lock_irqsave(&devtree_lock, flags);
685 	next = __of_get_next_child(node, prev);
686 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
687 	return next;
688 }
689 EXPORT_SYMBOL(of_get_next_child);
690 
691 /**
692  *	of_get_next_available_child - Find the next available child node
693  *	@node:	parent node
694  *	@prev:	previous child of the parent node, or NULL to get first
695  *
696  *      This function is like of_get_next_child(), except that it
697  *      automatically skips any disabled nodes (i.e. status = "disabled").
698  */
699 struct device_node *of_get_next_available_child(const struct device_node *node,
700 	struct device_node *prev)
701 {
702 	struct device_node *next;
703 	unsigned long flags;
704 
705 	if (!node)
706 		return NULL;
707 
708 	raw_spin_lock_irqsave(&devtree_lock, flags);
709 	next = prev ? prev->sibling : node->child;
710 	for (; next; next = next->sibling) {
711 		if (!__of_device_is_available(next))
712 			continue;
713 		if (of_node_get(next))
714 			break;
715 	}
716 	of_node_put(prev);
717 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
718 	return next;
719 }
720 EXPORT_SYMBOL(of_get_next_available_child);
721 
722 /**
723  *	of_get_child_by_name - Find the child node by name for a given parent
724  *	@node:	parent node
725  *	@name:	child name to look for.
726  *
727  *      This function looks for child node for given matching name
728  *
729  *	Returns a node pointer if found, with refcount incremented, use
730  *	of_node_put() on it when done.
731  *	Returns NULL if node is not found.
732  */
733 struct device_node *of_get_child_by_name(const struct device_node *node,
734 				const char *name)
735 {
736 	struct device_node *child;
737 
738 	for_each_child_of_node(node, child)
739 		if (child->name && (of_node_cmp(child->name, name) == 0))
740 			break;
741 	return child;
742 }
743 EXPORT_SYMBOL(of_get_child_by_name);
744 
745 struct device_node *__of_find_node_by_path(struct device_node *parent,
746 						const char *path)
747 {
748 	struct device_node *child;
749 	int len;
750 
751 	len = strcspn(path, "/:");
752 	if (!len)
753 		return NULL;
754 
755 	__for_each_child_of_node(parent, child) {
756 		const char *name = kbasename(child->full_name);
757 		if (strncmp(path, name, len) == 0 && (strlen(name) == len))
758 			return child;
759 	}
760 	return NULL;
761 }
762 
763 struct device_node *__of_find_node_by_full_path(struct device_node *node,
764 						const char *path)
765 {
766 	const char *separator = strchr(path, ':');
767 
768 	while (node && *path == '/') {
769 		struct device_node *tmp = node;
770 
771 		path++; /* Increment past '/' delimiter */
772 		node = __of_find_node_by_path(node, path);
773 		of_node_put(tmp);
774 		path = strchrnul(path, '/');
775 		if (separator && separator < path)
776 			break;
777 	}
778 	return node;
779 }
780 
781 /**
782  *	of_find_node_opts_by_path - Find a node matching a full OF path
783  *	@path: Either the full path to match, or if the path does not
784  *	       start with '/', the name of a property of the /aliases
785  *	       node (an alias).  In the case of an alias, the node
786  *	       matching the alias' value will be returned.
787  *	@opts: Address of a pointer into which to store the start of
788  *	       an options string appended to the end of the path with
789  *	       a ':' separator.
790  *
791  *	Valid paths:
792  *		/foo/bar	Full path
793  *		foo		Valid alias
794  *		foo/bar		Valid alias + relative path
795  *
796  *	Returns a node pointer with refcount incremented, use
797  *	of_node_put() on it when done.
798  */
799 struct device_node *of_find_node_opts_by_path(const char *path, const char **opts)
800 {
801 	struct device_node *np = NULL;
802 	struct property *pp;
803 	unsigned long flags;
804 	const char *separator = strchr(path, ':');
805 
806 	if (opts)
807 		*opts = separator ? separator + 1 : NULL;
808 
809 	if (strcmp(path, "/") == 0)
810 		return of_node_get(of_root);
811 
812 	/* The path could begin with an alias */
813 	if (*path != '/') {
814 		int len;
815 		const char *p = separator;
816 
817 		if (!p)
818 			p = strchrnul(path, '/');
819 		len = p - path;
820 
821 		/* of_aliases must not be NULL */
822 		if (!of_aliases)
823 			return NULL;
824 
825 		for_each_property_of_node(of_aliases, pp) {
826 			if (strlen(pp->name) == len && !strncmp(pp->name, path, len)) {
827 				np = of_find_node_by_path(pp->value);
828 				break;
829 			}
830 		}
831 		if (!np)
832 			return NULL;
833 		path = p;
834 	}
835 
836 	/* Step down the tree matching path components */
837 	raw_spin_lock_irqsave(&devtree_lock, flags);
838 	if (!np)
839 		np = of_node_get(of_root);
840 	np = __of_find_node_by_full_path(np, path);
841 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
842 	return np;
843 }
844 EXPORT_SYMBOL(of_find_node_opts_by_path);
845 
846 /**
847  *	of_find_node_by_name - Find a node by its "name" property
848  *	@from:	The node to start searching from or NULL; the node
849  *		you pass will not be searched, only the next one
850  *		will. Typically, you pass what the previous call
851  *		returned. of_node_put() will be called on @from.
852  *	@name:	The name string to match against
853  *
854  *	Returns a node pointer with refcount incremented, use
855  *	of_node_put() on it when done.
856  */
857 struct device_node *of_find_node_by_name(struct device_node *from,
858 	const char *name)
859 {
860 	struct device_node *np;
861 	unsigned long flags;
862 
863 	raw_spin_lock_irqsave(&devtree_lock, flags);
864 	for_each_of_allnodes_from(from, np)
865 		if (np->name && (of_node_cmp(np->name, name) == 0)
866 		    && of_node_get(np))
867 			break;
868 	of_node_put(from);
869 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
870 	return np;
871 }
872 EXPORT_SYMBOL(of_find_node_by_name);
873 
874 /**
875  *	of_find_node_by_type - Find a node by its "device_type" property
876  *	@from:	The node to start searching from, or NULL to start searching
877  *		the entire device tree. The node you pass will not be
878  *		searched, only the next one will; typically, you pass
879  *		what the previous call returned. of_node_put() will be
880  *		called on from for you.
881  *	@type:	The type string to match against
882  *
883  *	Returns a node pointer with refcount incremented, use
884  *	of_node_put() on it when done.
885  */
886 struct device_node *of_find_node_by_type(struct device_node *from,
887 	const char *type)
888 {
889 	struct device_node *np;
890 	unsigned long flags;
891 
892 	raw_spin_lock_irqsave(&devtree_lock, flags);
893 	for_each_of_allnodes_from(from, np)
894 		if (np->type && (of_node_cmp(np->type, type) == 0)
895 		    && of_node_get(np))
896 			break;
897 	of_node_put(from);
898 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
899 	return np;
900 }
901 EXPORT_SYMBOL(of_find_node_by_type);
902 
903 /**
904  *	of_find_compatible_node - Find a node based on type and one of the
905  *                                tokens in its "compatible" property
906  *	@from:		The node to start searching from or NULL, the node
907  *			you pass will not be searched, only the next one
908  *			will; typically, you pass what the previous call
909  *			returned. of_node_put() will be called on it
910  *	@type:		The type string to match "device_type" or NULL to ignore
911  *	@compatible:	The string to match to one of the tokens in the device
912  *			"compatible" list.
913  *
914  *	Returns a node pointer with refcount incremented, use
915  *	of_node_put() on it when done.
916  */
917 struct device_node *of_find_compatible_node(struct device_node *from,
918 	const char *type, const char *compatible)
919 {
920 	struct device_node *np;
921 	unsigned long flags;
922 
923 	raw_spin_lock_irqsave(&devtree_lock, flags);
924 	for_each_of_allnodes_from(from, np)
925 		if (__of_device_is_compatible(np, compatible, type, NULL) &&
926 		    of_node_get(np))
927 			break;
928 	of_node_put(from);
929 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
930 	return np;
931 }
932 EXPORT_SYMBOL(of_find_compatible_node);
933 
934 /**
935  *	of_find_node_with_property - Find a node which has a property with
936  *                                   the given name.
937  *	@from:		The node to start searching from or NULL, the node
938  *			you pass will not be searched, only the next one
939  *			will; typically, you pass what the previous call
940  *			returned. of_node_put() will be called on it
941  *	@prop_name:	The name of the property to look for.
942  *
943  *	Returns a node pointer with refcount incremented, use
944  *	of_node_put() on it when done.
945  */
946 struct device_node *of_find_node_with_property(struct device_node *from,
947 	const char *prop_name)
948 {
949 	struct device_node *np;
950 	struct property *pp;
951 	unsigned long flags;
952 
953 	raw_spin_lock_irqsave(&devtree_lock, flags);
954 	for_each_of_allnodes_from(from, np) {
955 		for (pp = np->properties; pp; pp = pp->next) {
956 			if (of_prop_cmp(pp->name, prop_name) == 0) {
957 				of_node_get(np);
958 				goto out;
959 			}
960 		}
961 	}
962 out:
963 	of_node_put(from);
964 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
965 	return np;
966 }
967 EXPORT_SYMBOL(of_find_node_with_property);
968 
969 static
970 const struct of_device_id *__of_match_node(const struct of_device_id *matches,
971 					   const struct device_node *node)
972 {
973 	const struct of_device_id *best_match = NULL;
974 	int score, best_score = 0;
975 
976 	if (!matches)
977 		return NULL;
978 
979 	for (; matches->name[0] || matches->type[0] || matches->compatible[0]; matches++) {
980 		score = __of_device_is_compatible(node, matches->compatible,
981 						  matches->type, matches->name);
982 		if (score > best_score) {
983 			best_match = matches;
984 			best_score = score;
985 		}
986 	}
987 
988 	return best_match;
989 }
990 
991 /**
992  * of_match_node - Tell if a device_node has a matching of_match structure
993  *	@matches:	array of of device match structures to search in
994  *	@node:		the of device structure to match against
995  *
996  *	Low level utility function used by device matching.
997  */
998 const struct of_device_id *of_match_node(const struct of_device_id *matches,
999 					 const struct device_node *node)
1000 {
1001 	const struct of_device_id *match;
1002 	unsigned long flags;
1003 
1004 	raw_spin_lock_irqsave(&devtree_lock, flags);
1005 	match = __of_match_node(matches, node);
1006 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1007 	return match;
1008 }
1009 EXPORT_SYMBOL(of_match_node);
1010 
1011 /**
1012  *	of_find_matching_node_and_match - Find a node based on an of_device_id
1013  *					  match table.
1014  *	@from:		The node to start searching from or NULL, the node
1015  *			you pass will not be searched, only the next one
1016  *			will; typically, you pass what the previous call
1017  *			returned. of_node_put() will be called on it
1018  *	@matches:	array of of device match structures to search in
1019  *	@match		Updated to point at the matches entry which matched
1020  *
1021  *	Returns a node pointer with refcount incremented, use
1022  *	of_node_put() on it when done.
1023  */
1024 struct device_node *of_find_matching_node_and_match(struct device_node *from,
1025 					const struct of_device_id *matches,
1026 					const struct of_device_id **match)
1027 {
1028 	struct device_node *np;
1029 	const struct of_device_id *m;
1030 	unsigned long flags;
1031 
1032 	if (match)
1033 		*match = NULL;
1034 
1035 	raw_spin_lock_irqsave(&devtree_lock, flags);
1036 	for_each_of_allnodes_from(from, np) {
1037 		m = __of_match_node(matches, np);
1038 		if (m && of_node_get(np)) {
1039 			if (match)
1040 				*match = m;
1041 			break;
1042 		}
1043 	}
1044 	of_node_put(from);
1045 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1046 	return np;
1047 }
1048 EXPORT_SYMBOL(of_find_matching_node_and_match);
1049 
1050 /**
1051  * of_modalias_node - Lookup appropriate modalias for a device node
1052  * @node:	pointer to a device tree node
1053  * @modalias:	Pointer to buffer that modalias value will be copied into
1054  * @len:	Length of modalias value
1055  *
1056  * Based on the value of the compatible property, this routine will attempt
1057  * to choose an appropriate modalias value for a particular device tree node.
1058  * It does this by stripping the manufacturer prefix (as delimited by a ',')
1059  * from the first entry in the compatible list property.
1060  *
1061  * This routine returns 0 on success, <0 on failure.
1062  */
1063 int of_modalias_node(struct device_node *node, char *modalias, int len)
1064 {
1065 	const char *compatible, *p;
1066 	int cplen;
1067 
1068 	compatible = of_get_property(node, "compatible", &cplen);
1069 	if (!compatible || strlen(compatible) > cplen)
1070 		return -ENODEV;
1071 	p = strchr(compatible, ',');
1072 	strlcpy(modalias, p ? p + 1 : compatible, len);
1073 	return 0;
1074 }
1075 EXPORT_SYMBOL_GPL(of_modalias_node);
1076 
1077 /**
1078  * of_find_node_by_phandle - Find a node given a phandle
1079  * @handle:	phandle of the node to find
1080  *
1081  * Returns a node pointer with refcount incremented, use
1082  * of_node_put() on it when done.
1083  */
1084 struct device_node *of_find_node_by_phandle(phandle handle)
1085 {
1086 	struct device_node *np = NULL;
1087 	unsigned long flags;
1088 	phandle masked_handle;
1089 
1090 	if (!handle)
1091 		return NULL;
1092 
1093 	raw_spin_lock_irqsave(&devtree_lock, flags);
1094 
1095 	masked_handle = handle & phandle_cache_mask;
1096 
1097 	if (phandle_cache) {
1098 		if (phandle_cache[masked_handle] &&
1099 		    handle == phandle_cache[masked_handle]->phandle)
1100 			np = phandle_cache[masked_handle];
1101 	}
1102 
1103 	if (!np) {
1104 		for_each_of_allnodes(np)
1105 			if (np->phandle == handle) {
1106 				if (phandle_cache)
1107 					phandle_cache[masked_handle] = np;
1108 				break;
1109 			}
1110 	}
1111 
1112 	of_node_get(np);
1113 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1114 	return np;
1115 }
1116 EXPORT_SYMBOL(of_find_node_by_phandle);
1117 
1118 void of_print_phandle_args(const char *msg, const struct of_phandle_args *args)
1119 {
1120 	int i;
1121 	printk("%s %pOF", msg, args->np);
1122 	for (i = 0; i < args->args_count; i++) {
1123 		const char delim = i ? ',' : ':';
1124 
1125 		pr_cont("%c%08x", delim, args->args[i]);
1126 	}
1127 	pr_cont("\n");
1128 }
1129 
1130 int of_phandle_iterator_init(struct of_phandle_iterator *it,
1131 		const struct device_node *np,
1132 		const char *list_name,
1133 		const char *cells_name,
1134 		int cell_count)
1135 {
1136 	const __be32 *list;
1137 	int size;
1138 
1139 	memset(it, 0, sizeof(*it));
1140 
1141 	list = of_get_property(np, list_name, &size);
1142 	if (!list)
1143 		return -ENOENT;
1144 
1145 	it->cells_name = cells_name;
1146 	it->cell_count = cell_count;
1147 	it->parent = np;
1148 	it->list_end = list + size / sizeof(*list);
1149 	it->phandle_end = list;
1150 	it->cur = list;
1151 
1152 	return 0;
1153 }
1154 EXPORT_SYMBOL_GPL(of_phandle_iterator_init);
1155 
1156 int of_phandle_iterator_next(struct of_phandle_iterator *it)
1157 {
1158 	uint32_t count = 0;
1159 
1160 	if (it->node) {
1161 		of_node_put(it->node);
1162 		it->node = NULL;
1163 	}
1164 
1165 	if (!it->cur || it->phandle_end >= it->list_end)
1166 		return -ENOENT;
1167 
1168 	it->cur = it->phandle_end;
1169 
1170 	/* If phandle is 0, then it is an empty entry with no arguments. */
1171 	it->phandle = be32_to_cpup(it->cur++);
1172 
1173 	if (it->phandle) {
1174 
1175 		/*
1176 		 * Find the provider node and parse the #*-cells property to
1177 		 * determine the argument length.
1178 		 */
1179 		it->node = of_find_node_by_phandle(it->phandle);
1180 
1181 		if (it->cells_name) {
1182 			if (!it->node) {
1183 				pr_err("%pOF: could not find phandle\n",
1184 				       it->parent);
1185 				goto err;
1186 			}
1187 
1188 			if (of_property_read_u32(it->node, it->cells_name,
1189 						 &count)) {
1190 				pr_err("%pOF: could not get %s for %pOF\n",
1191 				       it->parent,
1192 				       it->cells_name,
1193 				       it->node);
1194 				goto err;
1195 			}
1196 		} else {
1197 			count = it->cell_count;
1198 		}
1199 
1200 		/*
1201 		 * Make sure that the arguments actually fit in the remaining
1202 		 * property data length
1203 		 */
1204 		if (it->cur + count > it->list_end) {
1205 			pr_err("%pOF: arguments longer than property\n",
1206 			       it->parent);
1207 			goto err;
1208 		}
1209 	}
1210 
1211 	it->phandle_end = it->cur + count;
1212 	it->cur_count = count;
1213 
1214 	return 0;
1215 
1216 err:
1217 	if (it->node) {
1218 		of_node_put(it->node);
1219 		it->node = NULL;
1220 	}
1221 
1222 	return -EINVAL;
1223 }
1224 EXPORT_SYMBOL_GPL(of_phandle_iterator_next);
1225 
1226 int of_phandle_iterator_args(struct of_phandle_iterator *it,
1227 			     uint32_t *args,
1228 			     int size)
1229 {
1230 	int i, count;
1231 
1232 	count = it->cur_count;
1233 
1234 	if (WARN_ON(size < count))
1235 		count = size;
1236 
1237 	for (i = 0; i < count; i++)
1238 		args[i] = be32_to_cpup(it->cur++);
1239 
1240 	return count;
1241 }
1242 
1243 static int __of_parse_phandle_with_args(const struct device_node *np,
1244 					const char *list_name,
1245 					const char *cells_name,
1246 					int cell_count, int index,
1247 					struct of_phandle_args *out_args)
1248 {
1249 	struct of_phandle_iterator it;
1250 	int rc, cur_index = 0;
1251 
1252 	/* Loop over the phandles until all the requested entry is found */
1253 	of_for_each_phandle(&it, rc, np, list_name, cells_name, cell_count) {
1254 		/*
1255 		 * All of the error cases bail out of the loop, so at
1256 		 * this point, the parsing is successful. If the requested
1257 		 * index matches, then fill the out_args structure and return,
1258 		 * or return -ENOENT for an empty entry.
1259 		 */
1260 		rc = -ENOENT;
1261 		if (cur_index == index) {
1262 			if (!it.phandle)
1263 				goto err;
1264 
1265 			if (out_args) {
1266 				int c;
1267 
1268 				c = of_phandle_iterator_args(&it,
1269 							     out_args->args,
1270 							     MAX_PHANDLE_ARGS);
1271 				out_args->np = it.node;
1272 				out_args->args_count = c;
1273 			} else {
1274 				of_node_put(it.node);
1275 			}
1276 
1277 			/* Found it! return success */
1278 			return 0;
1279 		}
1280 
1281 		cur_index++;
1282 	}
1283 
1284 	/*
1285 	 * Unlock node before returning result; will be one of:
1286 	 * -ENOENT : index is for empty phandle
1287 	 * -EINVAL : parsing error on data
1288 	 */
1289 
1290  err:
1291 	of_node_put(it.node);
1292 	return rc;
1293 }
1294 
1295 /**
1296  * of_parse_phandle - Resolve a phandle property to a device_node pointer
1297  * @np: Pointer to device node holding phandle property
1298  * @phandle_name: Name of property holding a phandle value
1299  * @index: For properties holding a table of phandles, this is the index into
1300  *         the table
1301  *
1302  * Returns the device_node pointer with refcount incremented.  Use
1303  * of_node_put() on it when done.
1304  */
1305 struct device_node *of_parse_phandle(const struct device_node *np,
1306 				     const char *phandle_name, int index)
1307 {
1308 	struct of_phandle_args args;
1309 
1310 	if (index < 0)
1311 		return NULL;
1312 
1313 	if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0,
1314 					 index, &args))
1315 		return NULL;
1316 
1317 	return args.np;
1318 }
1319 EXPORT_SYMBOL(of_parse_phandle);
1320 
1321 /**
1322  * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
1323  * @np:		pointer to a device tree node containing a list
1324  * @list_name:	property name that contains a list
1325  * @cells_name:	property name that specifies phandles' arguments count
1326  * @index:	index of a phandle to parse out
1327  * @out_args:	optional pointer to output arguments structure (will be filled)
1328  *
1329  * This function is useful to parse lists of phandles and their arguments.
1330  * Returns 0 on success and fills out_args, on error returns appropriate
1331  * errno value.
1332  *
1333  * Caller is responsible to call of_node_put() on the returned out_args->np
1334  * pointer.
1335  *
1336  * Example:
1337  *
1338  * phandle1: node1 {
1339  *	#list-cells = <2>;
1340  * }
1341  *
1342  * phandle2: node2 {
1343  *	#list-cells = <1>;
1344  * }
1345  *
1346  * node3 {
1347  *	list = <&phandle1 1 2 &phandle2 3>;
1348  * }
1349  *
1350  * To get a device_node of the `node2' node you may call this:
1351  * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
1352  */
1353 int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,
1354 				const char *cells_name, int index,
1355 				struct of_phandle_args *out_args)
1356 {
1357 	if (index < 0)
1358 		return -EINVAL;
1359 	return __of_parse_phandle_with_args(np, list_name, cells_name, 0,
1360 					    index, out_args);
1361 }
1362 EXPORT_SYMBOL(of_parse_phandle_with_args);
1363 
1364 /**
1365  * of_parse_phandle_with_args_map() - Find a node pointed by phandle in a list and remap it
1366  * @np:		pointer to a device tree node containing a list
1367  * @list_name:	property name that contains a list
1368  * @stem_name:	stem of property names that specify phandles' arguments count
1369  * @index:	index of a phandle to parse out
1370  * @out_args:	optional pointer to output arguments structure (will be filled)
1371  *
1372  * This function is useful to parse lists of phandles and their arguments.
1373  * Returns 0 on success and fills out_args, on error returns appropriate errno
1374  * value. The difference between this function and of_parse_phandle_with_args()
1375  * is that this API remaps a phandle if the node the phandle points to has
1376  * a <@stem_name>-map property.
1377  *
1378  * Caller is responsible to call of_node_put() on the returned out_args->np
1379  * pointer.
1380  *
1381  * Example:
1382  *
1383  * phandle1: node1 {
1384  *	#list-cells = <2>;
1385  * }
1386  *
1387  * phandle2: node2 {
1388  *	#list-cells = <1>;
1389  * }
1390  *
1391  * phandle3: node3 {
1392  * 	#list-cells = <1>;
1393  * 	list-map = <0 &phandle2 3>,
1394  * 		   <1 &phandle2 2>,
1395  * 		   <2 &phandle1 5 1>;
1396  *	list-map-mask = <0x3>;
1397  * };
1398  *
1399  * node4 {
1400  *	list = <&phandle1 1 2 &phandle3 0>;
1401  * }
1402  *
1403  * To get a device_node of the `node2' node you may call this:
1404  * of_parse_phandle_with_args(node4, "list", "list", 1, &args);
1405  */
1406 int of_parse_phandle_with_args_map(const struct device_node *np,
1407 				   const char *list_name,
1408 				   const char *stem_name,
1409 				   int index, struct of_phandle_args *out_args)
1410 {
1411 	char *cells_name, *map_name = NULL, *mask_name = NULL;
1412 	char *pass_name = NULL;
1413 	struct device_node *cur, *new = NULL;
1414 	const __be32 *map, *mask, *pass;
1415 	static const __be32 dummy_mask[] = { [0 ... MAX_PHANDLE_ARGS] = ~0 };
1416 	static const __be32 dummy_pass[] = { [0 ... MAX_PHANDLE_ARGS] = 0 };
1417 	__be32 initial_match_array[MAX_PHANDLE_ARGS];
1418 	const __be32 *match_array = initial_match_array;
1419 	int i, ret, map_len, match;
1420 	u32 list_size, new_size;
1421 
1422 	if (index < 0)
1423 		return -EINVAL;
1424 
1425 	cells_name = kasprintf(GFP_KERNEL, "#%s-cells", stem_name);
1426 	if (!cells_name)
1427 		return -ENOMEM;
1428 
1429 	ret = -ENOMEM;
1430 	map_name = kasprintf(GFP_KERNEL, "%s-map", stem_name);
1431 	if (!map_name)
1432 		goto free;
1433 
1434 	mask_name = kasprintf(GFP_KERNEL, "%s-map-mask", stem_name);
1435 	if (!mask_name)
1436 		goto free;
1437 
1438 	pass_name = kasprintf(GFP_KERNEL, "%s-map-pass-thru", stem_name);
1439 	if (!pass_name)
1440 		goto free;
1441 
1442 	ret = __of_parse_phandle_with_args(np, list_name, cells_name, 0, index,
1443 					   out_args);
1444 	if (ret)
1445 		goto free;
1446 
1447 	/* Get the #<list>-cells property */
1448 	cur = out_args->np;
1449 	ret = of_property_read_u32(cur, cells_name, &list_size);
1450 	if (ret < 0)
1451 		goto put;
1452 
1453 	/* Precalculate the match array - this simplifies match loop */
1454 	for (i = 0; i < list_size; i++)
1455 		initial_match_array[i] = cpu_to_be32(out_args->args[i]);
1456 
1457 	ret = -EINVAL;
1458 	while (cur) {
1459 		/* Get the <list>-map property */
1460 		map = of_get_property(cur, map_name, &map_len);
1461 		if (!map) {
1462 			ret = 0;
1463 			goto free;
1464 		}
1465 		map_len /= sizeof(u32);
1466 
1467 		/* Get the <list>-map-mask property (optional) */
1468 		mask = of_get_property(cur, mask_name, NULL);
1469 		if (!mask)
1470 			mask = dummy_mask;
1471 		/* Iterate through <list>-map property */
1472 		match = 0;
1473 		while (map_len > (list_size + 1) && !match) {
1474 			/* Compare specifiers */
1475 			match = 1;
1476 			for (i = 0; i < list_size; i++, map_len--)
1477 				match &= !((match_array[i] ^ *map++) & mask[i]);
1478 
1479 			of_node_put(new);
1480 			new = of_find_node_by_phandle(be32_to_cpup(map));
1481 			map++;
1482 			map_len--;
1483 
1484 			/* Check if not found */
1485 			if (!new)
1486 				goto put;
1487 
1488 			if (!of_device_is_available(new))
1489 				match = 0;
1490 
1491 			ret = of_property_read_u32(new, cells_name, &new_size);
1492 			if (ret)
1493 				goto put;
1494 
1495 			/* Check for malformed properties */
1496 			if (WARN_ON(new_size > MAX_PHANDLE_ARGS))
1497 				goto put;
1498 			if (map_len < new_size)
1499 				goto put;
1500 
1501 			/* Move forward by new node's #<list>-cells amount */
1502 			map += new_size;
1503 			map_len -= new_size;
1504 		}
1505 		if (!match)
1506 			goto put;
1507 
1508 		/* Get the <list>-map-pass-thru property (optional) */
1509 		pass = of_get_property(cur, pass_name, NULL);
1510 		if (!pass)
1511 			pass = dummy_pass;
1512 
1513 		/*
1514 		 * Successfully parsed a <list>-map translation; copy new
1515 		 * specifier into the out_args structure, keeping the
1516 		 * bits specified in <list>-map-pass-thru.
1517 		 */
1518 		match_array = map - new_size;
1519 		for (i = 0; i < new_size; i++) {
1520 			__be32 val = *(map - new_size + i);
1521 
1522 			if (i < list_size) {
1523 				val &= ~pass[i];
1524 				val |= cpu_to_be32(out_args->args[i]) & pass[i];
1525 			}
1526 
1527 			out_args->args[i] = be32_to_cpu(val);
1528 		}
1529 		out_args->args_count = list_size = new_size;
1530 		/* Iterate again with new provider */
1531 		out_args->np = new;
1532 		of_node_put(cur);
1533 		cur = new;
1534 	}
1535 put:
1536 	of_node_put(cur);
1537 	of_node_put(new);
1538 free:
1539 	kfree(mask_name);
1540 	kfree(map_name);
1541 	kfree(cells_name);
1542 	kfree(pass_name);
1543 
1544 	return ret;
1545 }
1546 EXPORT_SYMBOL(of_parse_phandle_with_args_map);
1547 
1548 /**
1549  * of_parse_phandle_with_fixed_args() - Find a node pointed by phandle in a list
1550  * @np:		pointer to a device tree node containing a list
1551  * @list_name:	property name that contains a list
1552  * @cell_count: number of argument cells following the phandle
1553  * @index:	index of a phandle to parse out
1554  * @out_args:	optional pointer to output arguments structure (will be filled)
1555  *
1556  * This function is useful to parse lists of phandles and their arguments.
1557  * Returns 0 on success and fills out_args, on error returns appropriate
1558  * errno value.
1559  *
1560  * Caller is responsible to call of_node_put() on the returned out_args->np
1561  * pointer.
1562  *
1563  * Example:
1564  *
1565  * phandle1: node1 {
1566  * }
1567  *
1568  * phandle2: node2 {
1569  * }
1570  *
1571  * node3 {
1572  *	list = <&phandle1 0 2 &phandle2 2 3>;
1573  * }
1574  *
1575  * To get a device_node of the `node2' node you may call this:
1576  * of_parse_phandle_with_fixed_args(node3, "list", 2, 1, &args);
1577  */
1578 int of_parse_phandle_with_fixed_args(const struct device_node *np,
1579 				const char *list_name, int cell_count,
1580 				int index, struct of_phandle_args *out_args)
1581 {
1582 	if (index < 0)
1583 		return -EINVAL;
1584 	return __of_parse_phandle_with_args(np, list_name, NULL, cell_count,
1585 					   index, out_args);
1586 }
1587 EXPORT_SYMBOL(of_parse_phandle_with_fixed_args);
1588 
1589 /**
1590  * of_count_phandle_with_args() - Find the number of phandles references in a property
1591  * @np:		pointer to a device tree node containing a list
1592  * @list_name:	property name that contains a list
1593  * @cells_name:	property name that specifies phandles' arguments count
1594  *
1595  * Returns the number of phandle + argument tuples within a property. It
1596  * is a typical pattern to encode a list of phandle and variable
1597  * arguments into a single property. The number of arguments is encoded
1598  * by a property in the phandle-target node. For example, a gpios
1599  * property would contain a list of GPIO specifies consisting of a
1600  * phandle and 1 or more arguments. The number of arguments are
1601  * determined by the #gpio-cells property in the node pointed to by the
1602  * phandle.
1603  */
1604 int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
1605 				const char *cells_name)
1606 {
1607 	struct of_phandle_iterator it;
1608 	int rc, cur_index = 0;
1609 
1610 	rc = of_phandle_iterator_init(&it, np, list_name, cells_name, 0);
1611 	if (rc)
1612 		return rc;
1613 
1614 	while ((rc = of_phandle_iterator_next(&it)) == 0)
1615 		cur_index += 1;
1616 
1617 	if (rc != -ENOENT)
1618 		return rc;
1619 
1620 	return cur_index;
1621 }
1622 EXPORT_SYMBOL(of_count_phandle_with_args);
1623 
1624 /**
1625  * __of_add_property - Add a property to a node without lock operations
1626  */
1627 int __of_add_property(struct device_node *np, struct property *prop)
1628 {
1629 	struct property **next;
1630 
1631 	prop->next = NULL;
1632 	next = &np->properties;
1633 	while (*next) {
1634 		if (strcmp(prop->name, (*next)->name) == 0)
1635 			/* duplicate ! don't insert it */
1636 			return -EEXIST;
1637 
1638 		next = &(*next)->next;
1639 	}
1640 	*next = prop;
1641 
1642 	return 0;
1643 }
1644 
1645 /**
1646  * of_add_property - Add a property to a node
1647  */
1648 int of_add_property(struct device_node *np, struct property *prop)
1649 {
1650 	unsigned long flags;
1651 	int rc;
1652 
1653 	mutex_lock(&of_mutex);
1654 
1655 	raw_spin_lock_irqsave(&devtree_lock, flags);
1656 	rc = __of_add_property(np, prop);
1657 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1658 
1659 	if (!rc)
1660 		__of_add_property_sysfs(np, prop);
1661 
1662 	mutex_unlock(&of_mutex);
1663 
1664 	if (!rc)
1665 		of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop, NULL);
1666 
1667 	return rc;
1668 }
1669 
1670 int __of_remove_property(struct device_node *np, struct property *prop)
1671 {
1672 	struct property **next;
1673 
1674 	for (next = &np->properties; *next; next = &(*next)->next) {
1675 		if (*next == prop)
1676 			break;
1677 	}
1678 	if (*next == NULL)
1679 		return -ENODEV;
1680 
1681 	/* found the node */
1682 	*next = prop->next;
1683 	prop->next = np->deadprops;
1684 	np->deadprops = prop;
1685 
1686 	return 0;
1687 }
1688 
1689 /**
1690  * of_remove_property - Remove a property from a node.
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"
1695  * list, so it won't be found any more.
1696  */
1697 int of_remove_property(struct device_node *np, struct property *prop)
1698 {
1699 	unsigned long flags;
1700 	int rc;
1701 
1702 	if (!prop)
1703 		return -ENODEV;
1704 
1705 	mutex_lock(&of_mutex);
1706 
1707 	raw_spin_lock_irqsave(&devtree_lock, flags);
1708 	rc = __of_remove_property(np, prop);
1709 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1710 
1711 	if (!rc)
1712 		__of_remove_property_sysfs(np, prop);
1713 
1714 	mutex_unlock(&of_mutex);
1715 
1716 	if (!rc)
1717 		of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop, NULL);
1718 
1719 	return rc;
1720 }
1721 
1722 int __of_update_property(struct device_node *np, struct property *newprop,
1723 		struct property **oldpropp)
1724 {
1725 	struct property **next, *oldprop;
1726 
1727 	for (next = &np->properties; *next; next = &(*next)->next) {
1728 		if (of_prop_cmp((*next)->name, newprop->name) == 0)
1729 			break;
1730 	}
1731 	*oldpropp = oldprop = *next;
1732 
1733 	if (oldprop) {
1734 		/* replace the node */
1735 		newprop->next = oldprop->next;
1736 		*next = newprop;
1737 		oldprop->next = np->deadprops;
1738 		np->deadprops = oldprop;
1739 	} else {
1740 		/* new node */
1741 		newprop->next = NULL;
1742 		*next = newprop;
1743 	}
1744 
1745 	return 0;
1746 }
1747 
1748 /*
1749  * of_update_property - Update a property in a node, if the property does
1750  * not exist, add it.
1751  *
1752  * Note that we don't actually remove it, since we have given out
1753  * who-knows-how-many pointers to the data using get-property.
1754  * Instead we just move the property to the "dead properties" list,
1755  * and add the new property to the property list
1756  */
1757 int of_update_property(struct device_node *np, struct property *newprop)
1758 {
1759 	struct property *oldprop;
1760 	unsigned long flags;
1761 	int rc;
1762 
1763 	if (!newprop->name)
1764 		return -EINVAL;
1765 
1766 	mutex_lock(&of_mutex);
1767 
1768 	raw_spin_lock_irqsave(&devtree_lock, flags);
1769 	rc = __of_update_property(np, newprop, &oldprop);
1770 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1771 
1772 	if (!rc)
1773 		__of_update_property_sysfs(np, newprop, oldprop);
1774 
1775 	mutex_unlock(&of_mutex);
1776 
1777 	if (!rc)
1778 		of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop, oldprop);
1779 
1780 	return rc;
1781 }
1782 
1783 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
1784 			 int id, const char *stem, int stem_len)
1785 {
1786 	ap->np = np;
1787 	ap->id = id;
1788 	strncpy(ap->stem, stem, stem_len);
1789 	ap->stem[stem_len] = 0;
1790 	list_add_tail(&ap->link, &aliases_lookup);
1791 	pr_debug("adding DT alias:%s: stem=%s id=%i node=%pOF\n",
1792 		 ap->alias, ap->stem, ap->id, np);
1793 }
1794 
1795 /**
1796  * of_alias_scan - Scan all properties of the 'aliases' node
1797  *
1798  * The function scans all the properties of the 'aliases' node and populates
1799  * the global lookup table with the properties.  It returns the
1800  * number of alias properties found, or an error code in case of failure.
1801  *
1802  * @dt_alloc:	An allocator that provides a virtual address to memory
1803  *		for storing the resulting tree
1804  */
1805 void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
1806 {
1807 	struct property *pp;
1808 
1809 	of_aliases = of_find_node_by_path("/aliases");
1810 	of_chosen = of_find_node_by_path("/chosen");
1811 	if (of_chosen == NULL)
1812 		of_chosen = of_find_node_by_path("/chosen@0");
1813 
1814 	if (of_chosen) {
1815 		/* linux,stdout-path and /aliases/stdout are for legacy compatibility */
1816 		const char *name = NULL;
1817 
1818 		if (of_property_read_string(of_chosen, "stdout-path", &name))
1819 			of_property_read_string(of_chosen, "linux,stdout-path",
1820 						&name);
1821 		if (IS_ENABLED(CONFIG_PPC) && !name)
1822 			of_property_read_string(of_aliases, "stdout", &name);
1823 		if (name)
1824 			of_stdout = of_find_node_opts_by_path(name, &of_stdout_options);
1825 	}
1826 
1827 	if (!of_aliases)
1828 		return;
1829 
1830 	for_each_property_of_node(of_aliases, pp) {
1831 		const char *start = pp->name;
1832 		const char *end = start + strlen(start);
1833 		struct device_node *np;
1834 		struct alias_prop *ap;
1835 		int id, len;
1836 
1837 		/* Skip those we do not want to proceed */
1838 		if (!strcmp(pp->name, "name") ||
1839 		    !strcmp(pp->name, "phandle") ||
1840 		    !strcmp(pp->name, "linux,phandle"))
1841 			continue;
1842 
1843 		np = of_find_node_by_path(pp->value);
1844 		if (!np)
1845 			continue;
1846 
1847 		/* walk the alias backwards to extract the id and work out
1848 		 * the 'stem' string */
1849 		while (isdigit(*(end-1)) && end > start)
1850 			end--;
1851 		len = end - start;
1852 
1853 		if (kstrtoint(end, 10, &id) < 0)
1854 			continue;
1855 
1856 		/* Allocate an alias_prop with enough space for the stem */
1857 		ap = dt_alloc(sizeof(*ap) + len + 1, __alignof__(*ap));
1858 		if (!ap)
1859 			continue;
1860 		memset(ap, 0, sizeof(*ap) + len + 1);
1861 		ap->alias = start;
1862 		of_alias_add(ap, np, id, start, len);
1863 	}
1864 }
1865 
1866 /**
1867  * of_alias_get_id - Get alias id for the given device_node
1868  * @np:		Pointer to the given device_node
1869  * @stem:	Alias stem of the given device_node
1870  *
1871  * The function travels the lookup table to get the alias id for the given
1872  * device_node and alias stem.  It returns the alias id if found.
1873  */
1874 int of_alias_get_id(struct device_node *np, const char *stem)
1875 {
1876 	struct alias_prop *app;
1877 	int id = -ENODEV;
1878 
1879 	mutex_lock(&of_mutex);
1880 	list_for_each_entry(app, &aliases_lookup, link) {
1881 		if (strcmp(app->stem, stem) != 0)
1882 			continue;
1883 
1884 		if (np == app->np) {
1885 			id = app->id;
1886 			break;
1887 		}
1888 	}
1889 	mutex_unlock(&of_mutex);
1890 
1891 	return id;
1892 }
1893 EXPORT_SYMBOL_GPL(of_alias_get_id);
1894 
1895 /**
1896  * of_alias_get_highest_id - Get highest alias id for the given stem
1897  * @stem:	Alias stem to be examined
1898  *
1899  * The function travels the lookup table to get the highest alias id for the
1900  * given alias stem.  It returns the alias id if found.
1901  */
1902 int of_alias_get_highest_id(const char *stem)
1903 {
1904 	struct alias_prop *app;
1905 	int id = -ENODEV;
1906 
1907 	mutex_lock(&of_mutex);
1908 	list_for_each_entry(app, &aliases_lookup, link) {
1909 		if (strcmp(app->stem, stem) != 0)
1910 			continue;
1911 
1912 		if (app->id > id)
1913 			id = app->id;
1914 	}
1915 	mutex_unlock(&of_mutex);
1916 
1917 	return id;
1918 }
1919 EXPORT_SYMBOL_GPL(of_alias_get_highest_id);
1920 
1921 /**
1922  * of_console_check() - Test and setup console for DT setup
1923  * @dn - Pointer to device node
1924  * @name - Name to use for preferred console without index. ex. "ttyS"
1925  * @index - Index to use for preferred console.
1926  *
1927  * Check if the given device node matches the stdout-path property in the
1928  * /chosen node. If it does then register it as the preferred console and return
1929  * TRUE. Otherwise return FALSE.
1930  */
1931 bool of_console_check(struct device_node *dn, char *name, int index)
1932 {
1933 	if (!dn || dn != of_stdout || console_set_on_cmdline)
1934 		return false;
1935 
1936 	/*
1937 	 * XXX: cast `options' to char pointer to suppress complication
1938 	 * warnings: printk, UART and console drivers expect char pointer.
1939 	 */
1940 	return !add_preferred_console(name, index, (char *)of_stdout_options);
1941 }
1942 EXPORT_SYMBOL_GPL(of_console_check);
1943 
1944 /**
1945  *	of_find_next_cache_node - Find a node's subsidiary cache
1946  *	@np:	node of type "cpu" or "cache"
1947  *
1948  *	Returns a node pointer with refcount incremented, use
1949  *	of_node_put() on it when done.  Caller should hold a reference
1950  *	to np.
1951  */
1952 struct device_node *of_find_next_cache_node(const struct device_node *np)
1953 {
1954 	struct device_node *child, *cache_node;
1955 
1956 	cache_node = of_parse_phandle(np, "l2-cache", 0);
1957 	if (!cache_node)
1958 		cache_node = of_parse_phandle(np, "next-level-cache", 0);
1959 
1960 	if (cache_node)
1961 		return cache_node;
1962 
1963 	/* OF on pmac has nodes instead of properties named "l2-cache"
1964 	 * beneath CPU nodes.
1965 	 */
1966 	if (!strcmp(np->type, "cpu"))
1967 		for_each_child_of_node(np, child)
1968 			if (!strcmp(child->type, "cache"))
1969 				return child;
1970 
1971 	return NULL;
1972 }
1973 
1974 /**
1975  * of_find_last_cache_level - Find the level at which the last cache is
1976  * 		present for the given logical cpu
1977  *
1978  * @cpu: cpu number(logical index) for which the last cache level is needed
1979  *
1980  * Returns the the level at which the last cache is present. It is exactly
1981  * same as  the total number of cache levels for the given logical cpu.
1982  */
1983 int of_find_last_cache_level(unsigned int cpu)
1984 {
1985 	u32 cache_level = 0;
1986 	struct device_node *prev = NULL, *np = of_cpu_device_node_get(cpu);
1987 
1988 	while (np) {
1989 		prev = np;
1990 		of_node_put(np);
1991 		np = of_find_next_cache_node(np);
1992 	}
1993 
1994 	of_property_read_u32(prev, "cache-level", &cache_level);
1995 
1996 	return cache_level;
1997 }
1998