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/cleanup.h>
20 #include <linux/console.h>
21 #include <linux/ctype.h>
22 #include <linux/cpu.h>
23 #include <linux/module.h>
24 #include <linux/of.h>
25 #include <linux/of_device.h>
26 #include <linux/of_graph.h>
27 #include <linux/spinlock.h>
28 #include <linux/slab.h>
29 #include <linux/string.h>
30 #include <linux/proc_fs.h>
31 
32 #include "of_private.h"
33 
34 LIST_HEAD(aliases_lookup);
35 
36 struct device_node *of_root;
37 EXPORT_SYMBOL(of_root);
38 struct device_node *of_chosen;
39 EXPORT_SYMBOL(of_chosen);
40 struct device_node *of_aliases;
41 struct device_node *of_stdout;
42 static const char *of_stdout_options;
43 
44 struct kset *of_kset;
45 
46 /*
47  * Used to protect the of_aliases, to hold off addition of nodes to sysfs.
48  * This mutex must be held whenever modifications are being made to the
49  * device tree. The of_{attach,detach}_node() and
50  * of_{add,remove,update}_property() helpers make sure this happens.
51  */
52 DEFINE_MUTEX(of_mutex);
53 
54 /* use when traversing tree through the child, sibling,
55  * or parent members of struct device_node.
56  */
57 DEFINE_RAW_SPINLOCK(devtree_lock);
58 
of_node_name_eq(const struct device_node * np,const char * name)59 bool of_node_name_eq(const struct device_node *np, const char *name)
60 {
61 	const char *node_name;
62 	size_t len;
63 
64 	if (!np)
65 		return false;
66 
67 	node_name = kbasename(np->full_name);
68 	len = strchrnul(node_name, '@') - node_name;
69 
70 	return (strlen(name) == len) && (strncmp(node_name, name, len) == 0);
71 }
72 EXPORT_SYMBOL(of_node_name_eq);
73 
of_node_name_prefix(const struct device_node * np,const char * prefix)74 bool of_node_name_prefix(const struct device_node *np, const char *prefix)
75 {
76 	if (!np)
77 		return false;
78 
79 	return strncmp(kbasename(np->full_name), prefix, strlen(prefix)) == 0;
80 }
81 EXPORT_SYMBOL(of_node_name_prefix);
82 
__of_node_is_type(const struct device_node * np,const char * type)83 static bool __of_node_is_type(const struct device_node *np, const char *type)
84 {
85 	const char *match = __of_get_property(np, "device_type", NULL);
86 
87 	return np && match && type && !strcmp(match, type);
88 }
89 
90 #define EXCLUDED_DEFAULT_CELLS_PLATFORMS ( \
91 	IS_ENABLED(CONFIG_SPARC) || \
92 	of_find_compatible_node(NULL, NULL, "coreboot") \
93 )
94 
of_bus_n_addr_cells(struct device_node * np)95 int of_bus_n_addr_cells(struct device_node *np)
96 {
97 	u32 cells;
98 
99 	for (; np; np = np->parent) {
100 		if (!of_property_read_u32(np, "#address-cells", &cells))
101 			return cells;
102 		/*
103 		 * Default root value and walking parent nodes for "#address-cells"
104 		 * is deprecated. Any platforms which hit this warning should
105 		 * be added to the excluded list.
106 		 */
107 		WARN_ONCE(!EXCLUDED_DEFAULT_CELLS_PLATFORMS,
108 			  "Missing '#address-cells' in %pOF\n", np);
109 	}
110 	return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
111 }
112 
of_n_addr_cells(struct device_node * np)113 int of_n_addr_cells(struct device_node *np)
114 {
115 	if (np->parent)
116 		np = np->parent;
117 
118 	return of_bus_n_addr_cells(np);
119 }
120 EXPORT_SYMBOL(of_n_addr_cells);
121 
of_bus_n_size_cells(struct device_node * np)122 int of_bus_n_size_cells(struct device_node *np)
123 {
124 	u32 cells;
125 
126 	for (; np; np = np->parent) {
127 		if (!of_property_read_u32(np, "#size-cells", &cells))
128 			return cells;
129 		/*
130 		 * Default root value and walking parent nodes for "#size-cells"
131 		 * is deprecated. Any platforms which hit this warning should
132 		 * be added to the excluded list.
133 		 */
134 		WARN_ONCE(!EXCLUDED_DEFAULT_CELLS_PLATFORMS,
135 			  "Missing '#size-cells' in %pOF\n", np);
136 	}
137 	return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
138 }
139 
of_n_size_cells(struct device_node * np)140 int of_n_size_cells(struct device_node *np)
141 {
142 	if (np->parent)
143 		np = np->parent;
144 
145 	return of_bus_n_size_cells(np);
146 }
147 EXPORT_SYMBOL(of_n_size_cells);
148 
149 #ifdef CONFIG_NUMA
of_node_to_nid(struct device_node * np)150 int __weak of_node_to_nid(struct device_node *np)
151 {
152 	return NUMA_NO_NODE;
153 }
154 #endif
155 
156 #define OF_PHANDLE_CACHE_BITS	7
157 #define OF_PHANDLE_CACHE_SZ	BIT(OF_PHANDLE_CACHE_BITS)
158 
159 static struct device_node *phandle_cache[OF_PHANDLE_CACHE_SZ];
160 
of_phandle_cache_hash(phandle handle)161 static u32 of_phandle_cache_hash(phandle handle)
162 {
163 	return hash_32(handle, OF_PHANDLE_CACHE_BITS);
164 }
165 
166 /*
167  * Caller must hold devtree_lock.
168  */
__of_phandle_cache_inv_entry(phandle handle)169 void __of_phandle_cache_inv_entry(phandle handle)
170 {
171 	u32 handle_hash;
172 	struct device_node *np;
173 
174 	if (!handle)
175 		return;
176 
177 	handle_hash = of_phandle_cache_hash(handle);
178 
179 	np = phandle_cache[handle_hash];
180 	if (np && handle == np->phandle)
181 		phandle_cache[handle_hash] = NULL;
182 }
183 
of_core_init(void)184 void __init of_core_init(void)
185 {
186 	struct device_node *np;
187 
188 	of_platform_register_reconfig_notifier();
189 
190 	/* Create the kset, and register existing nodes */
191 	mutex_lock(&of_mutex);
192 	of_kset = kset_create_and_add("devicetree", NULL, firmware_kobj);
193 	if (!of_kset) {
194 		mutex_unlock(&of_mutex);
195 		pr_err("failed to register existing nodes\n");
196 		return;
197 	}
198 	for_each_of_allnodes(np) {
199 		__of_attach_node_sysfs(np);
200 		if (np->phandle && !phandle_cache[of_phandle_cache_hash(np->phandle)])
201 			phandle_cache[of_phandle_cache_hash(np->phandle)] = np;
202 	}
203 	mutex_unlock(&of_mutex);
204 
205 	/* Symlink in /proc as required by userspace ABI */
206 	if (of_root)
207 		proc_symlink("device-tree", NULL, "/sys/firmware/devicetree/base");
208 }
209 
__of_find_property(const struct device_node * np,const char * name,int * lenp)210 static struct property *__of_find_property(const struct device_node *np,
211 					   const char *name, int *lenp)
212 {
213 	struct property *pp;
214 
215 	if (!np)
216 		return NULL;
217 
218 	for (pp = np->properties; pp; pp = pp->next) {
219 		if (of_prop_cmp(pp->name, name) == 0) {
220 			if (lenp)
221 				*lenp = pp->length;
222 			break;
223 		}
224 	}
225 
226 	return pp;
227 }
228 
of_find_property(const struct device_node * np,const char * name,int * lenp)229 struct property *of_find_property(const struct device_node *np,
230 				  const char *name,
231 				  int *lenp)
232 {
233 	struct property *pp;
234 	unsigned long flags;
235 
236 	raw_spin_lock_irqsave(&devtree_lock, flags);
237 	pp = __of_find_property(np, name, lenp);
238 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
239 
240 	return pp;
241 }
242 EXPORT_SYMBOL(of_find_property);
243 
__of_find_all_nodes(struct device_node * prev)244 struct device_node *__of_find_all_nodes(struct device_node *prev)
245 {
246 	struct device_node *np;
247 	if (!prev) {
248 		np = of_root;
249 	} else if (prev->child) {
250 		np = prev->child;
251 	} else {
252 		/* Walk back up looking for a sibling, or the end of the structure */
253 		np = prev;
254 		while (np->parent && !np->sibling)
255 			np = np->parent;
256 		np = np->sibling; /* Might be null at the end of the tree */
257 	}
258 	return np;
259 }
260 
261 /**
262  * of_find_all_nodes - Get next node in global list
263  * @prev:	Previous node or NULL to start iteration
264  *		of_node_put() will be called on it
265  *
266  * Return: A node pointer with refcount incremented, use
267  * of_node_put() on it when done.
268  */
of_find_all_nodes(struct device_node * prev)269 struct device_node *of_find_all_nodes(struct device_node *prev)
270 {
271 	struct device_node *np;
272 	unsigned long flags;
273 
274 	raw_spin_lock_irqsave(&devtree_lock, flags);
275 	np = __of_find_all_nodes(prev);
276 	of_node_get(np);
277 	of_node_put(prev);
278 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
279 	return np;
280 }
281 EXPORT_SYMBOL(of_find_all_nodes);
282 
283 /*
284  * Find a property with a given name for a given node
285  * and return the value.
286  */
__of_get_property(const struct device_node * np,const char * name,int * lenp)287 const void *__of_get_property(const struct device_node *np,
288 			      const char *name, int *lenp)
289 {
290 	const struct property *pp = __of_find_property(np, name, lenp);
291 
292 	return pp ? pp->value : NULL;
293 }
294 
295 /*
296  * Find a property with a given name for a given node
297  * and return the value.
298  */
of_get_property(const struct device_node * np,const char * name,int * lenp)299 const void *of_get_property(const struct device_node *np, const char *name,
300 			    int *lenp)
301 {
302 	const struct property *pp = of_find_property(np, name, lenp);
303 
304 	return pp ? pp->value : NULL;
305 }
306 EXPORT_SYMBOL(of_get_property);
307 
308 /**
309  * __of_device_is_compatible() - Check if the node matches given constraints
310  * @device: pointer to node
311  * @compat: required compatible string, NULL or "" for any match
312  * @type: required device_type value, NULL or "" for any match
313  * @name: required node name, NULL or "" for any match
314  *
315  * Checks if the given @compat, @type and @name strings match the
316  * properties of the given @device. A constraints can be skipped by
317  * passing NULL or an empty string as the constraint.
318  *
319  * Returns 0 for no match, and a positive integer on match. The return
320  * value is a relative score with larger values indicating better
321  * matches. The score is weighted for the most specific compatible value
322  * to get the highest score. Matching type is next, followed by matching
323  * name. Practically speaking, this results in the following priority
324  * order for matches:
325  *
326  * 1. specific compatible && type && name
327  * 2. specific compatible && type
328  * 3. specific compatible && name
329  * 4. specific compatible
330  * 5. general compatible && type && name
331  * 6. general compatible && type
332  * 7. general compatible && name
333  * 8. general compatible
334  * 9. type && name
335  * 10. type
336  * 11. name
337  */
__of_device_is_compatible(const struct device_node * device,const char * compat,const char * type,const char * name)338 static int __of_device_is_compatible(const struct device_node *device,
339 				     const char *compat, const char *type, const char *name)
340 {
341 	const struct property *prop;
342 	const char *cp;
343 	int index = 0, score = 0;
344 
345 	/* Compatible match has highest priority */
346 	if (compat && compat[0]) {
347 		prop = __of_find_property(device, "compatible", NULL);
348 		for (cp = of_prop_next_string(prop, NULL); cp;
349 		     cp = of_prop_next_string(prop, cp), index++) {
350 			if (of_compat_cmp(cp, compat, strlen(compat)) == 0) {
351 				score = INT_MAX/2 - (index << 2);
352 				break;
353 			}
354 		}
355 		if (!score)
356 			return 0;
357 	}
358 
359 	/* Matching type is better than matching name */
360 	if (type && type[0]) {
361 		if (!__of_node_is_type(device, type))
362 			return 0;
363 		score += 2;
364 	}
365 
366 	/* Matching name is a bit better than not */
367 	if (name && name[0]) {
368 		if (!of_node_name_eq(device, name))
369 			return 0;
370 		score++;
371 	}
372 
373 	return score;
374 }
375 
376 /** Checks if the given "compat" string matches one of the strings in
377  * the device's "compatible" property
378  */
of_device_is_compatible(const struct device_node * device,const char * compat)379 int of_device_is_compatible(const struct device_node *device,
380 		const char *compat)
381 {
382 	unsigned long flags;
383 	int res;
384 
385 	raw_spin_lock_irqsave(&devtree_lock, flags);
386 	res = __of_device_is_compatible(device, compat, NULL, NULL);
387 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
388 	return res;
389 }
390 EXPORT_SYMBOL(of_device_is_compatible);
391 
392 /** Checks if the device is compatible with any of the entries in
393  *  a NULL terminated array of strings. Returns the best match
394  *  score or 0.
395  */
of_device_compatible_match(const struct device_node * device,const char * const * compat)396 int of_device_compatible_match(const struct device_node *device,
397 			       const char *const *compat)
398 {
399 	unsigned int tmp, score = 0;
400 
401 	if (!compat)
402 		return 0;
403 
404 	while (*compat) {
405 		tmp = of_device_is_compatible(device, *compat);
406 		if (tmp > score)
407 			score = tmp;
408 		compat++;
409 	}
410 
411 	return score;
412 }
413 EXPORT_SYMBOL_GPL(of_device_compatible_match);
414 
415 /**
416  * of_machine_compatible_match - Test root of device tree against a compatible array
417  * @compats: NULL terminated array of compatible strings to look for in root node's compatible property.
418  *
419  * Returns true if the root node has any of the given compatible values in its
420  * compatible property.
421  */
of_machine_compatible_match(const char * const * compats)422 bool of_machine_compatible_match(const char *const *compats)
423 {
424 	struct device_node *root;
425 	int rc = 0;
426 
427 	root = of_find_node_by_path("/");
428 	if (root) {
429 		rc = of_device_compatible_match(root, compats);
430 		of_node_put(root);
431 	}
432 
433 	return rc != 0;
434 }
435 EXPORT_SYMBOL(of_machine_compatible_match);
436 
__of_device_is_status(const struct device_node * device,const char * const * strings)437 static bool __of_device_is_status(const struct device_node *device,
438 				  const char * const*strings)
439 {
440 	const char *status;
441 	int statlen;
442 
443 	if (!device)
444 		return false;
445 
446 	status = __of_get_property(device, "status", &statlen);
447 	if (status == NULL)
448 		return false;
449 
450 	if (statlen > 0) {
451 		while (*strings) {
452 			unsigned int len = strlen(*strings);
453 
454 			if ((*strings)[len - 1] == '-') {
455 				if (!strncmp(status, *strings, len))
456 					return true;
457 			} else {
458 				if (!strcmp(status, *strings))
459 					return true;
460 			}
461 			strings++;
462 		}
463 	}
464 
465 	return false;
466 }
467 
468 /**
469  *  __of_device_is_available - check if a device is available for use
470  *
471  *  @device: Node to check for availability, with locks already held
472  *
473  *  Return: True if the status property is absent or set to "okay" or "ok",
474  *  false otherwise
475  */
__of_device_is_available(const struct device_node * device)476 static bool __of_device_is_available(const struct device_node *device)
477 {
478 	static const char * const ok[] = {"okay", "ok", NULL};
479 
480 	if (!device)
481 		return false;
482 
483 	return !__of_get_property(device, "status", NULL) ||
484 		__of_device_is_status(device, ok);
485 }
486 
487 /**
488  *  __of_device_is_reserved - check if a device is reserved
489  *
490  *  @device: Node to check for availability, with locks already held
491  *
492  *  Return: True if the status property is set to "reserved", false otherwise
493  */
__of_device_is_reserved(const struct device_node * device)494 static bool __of_device_is_reserved(const struct device_node *device)
495 {
496 	static const char * const reserved[] = {"reserved", NULL};
497 
498 	return __of_device_is_status(device, reserved);
499 }
500 
501 /**
502  *  of_device_is_available - check if a device is available for use
503  *
504  *  @device: Node to check for availability
505  *
506  *  Return: True if the status property is absent or set to "okay" or "ok",
507  *  false otherwise
508  */
of_device_is_available(const struct device_node * device)509 bool of_device_is_available(const struct device_node *device)
510 {
511 	unsigned long flags;
512 	bool res;
513 
514 	raw_spin_lock_irqsave(&devtree_lock, flags);
515 	res = __of_device_is_available(device);
516 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
517 	return res;
518 
519 }
520 EXPORT_SYMBOL(of_device_is_available);
521 
522 /**
523  *  __of_device_is_fail - check if a device has status "fail" or "fail-..."
524  *
525  *  @device: Node to check status for, with locks already held
526  *
527  *  Return: True if the status property is set to "fail" or "fail-..." (for any
528  *  error code suffix), false otherwise
529  */
__of_device_is_fail(const struct device_node * device)530 static bool __of_device_is_fail(const struct device_node *device)
531 {
532 	static const char * const fail[] = {"fail", "fail-", NULL};
533 
534 	return __of_device_is_status(device, fail);
535 }
536 
537 /**
538  *  of_device_is_big_endian - check if a device has BE registers
539  *
540  *  @device: Node to check for endianness
541  *
542  *  Return: True if the device has a "big-endian" property, or if the kernel
543  *  was compiled for BE *and* the device has a "native-endian" property.
544  *  Returns false otherwise.
545  *
546  *  Callers would nominally use ioread32be/iowrite32be if
547  *  of_device_is_big_endian() == true, or readl/writel otherwise.
548  */
of_device_is_big_endian(const struct device_node * device)549 bool of_device_is_big_endian(const struct device_node *device)
550 {
551 	if (of_property_read_bool(device, "big-endian"))
552 		return true;
553 	if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
554 	    of_property_read_bool(device, "native-endian"))
555 		return true;
556 	return false;
557 }
558 EXPORT_SYMBOL(of_device_is_big_endian);
559 
560 /**
561  * of_get_parent - Get a node's parent if any
562  * @node:	Node to get parent
563  *
564  * Return: A node pointer with refcount incremented, use
565  * of_node_put() on it when done.
566  */
of_get_parent(const struct device_node * node)567 struct device_node *of_get_parent(const struct device_node *node)
568 {
569 	struct device_node *np;
570 	unsigned long flags;
571 
572 	if (!node)
573 		return NULL;
574 
575 	raw_spin_lock_irqsave(&devtree_lock, flags);
576 	np = of_node_get(node->parent);
577 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
578 	return np;
579 }
580 EXPORT_SYMBOL(of_get_parent);
581 
582 /**
583  * of_get_next_parent - Iterate to a node's parent
584  * @node:	Node to get parent of
585  *
586  * This is like of_get_parent() except that it drops the
587  * refcount on the passed node, making it suitable for iterating
588  * through a node's parents.
589  *
590  * Return: A node pointer with refcount incremented, use
591  * of_node_put() on it when done.
592  */
of_get_next_parent(struct device_node * node)593 struct device_node *of_get_next_parent(struct device_node *node)
594 {
595 	struct device_node *parent;
596 	unsigned long flags;
597 
598 	if (!node)
599 		return NULL;
600 
601 	raw_spin_lock_irqsave(&devtree_lock, flags);
602 	parent = of_node_get(node->parent);
603 	of_node_put(node);
604 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
605 	return parent;
606 }
607 EXPORT_SYMBOL(of_get_next_parent);
608 
__of_get_next_child(const struct device_node * node,struct device_node * prev)609 static struct device_node *__of_get_next_child(const struct device_node *node,
610 						struct device_node *prev)
611 {
612 	struct device_node *next;
613 
614 	if (!node)
615 		return NULL;
616 
617 	next = prev ? prev->sibling : node->child;
618 	of_node_get(next);
619 	of_node_put(prev);
620 	return next;
621 }
622 #define __for_each_child_of_node(parent, child) \
623 	for (child = __of_get_next_child(parent, NULL); child != NULL; \
624 	     child = __of_get_next_child(parent, child))
625 
626 /**
627  * of_get_next_child - Iterate a node childs
628  * @node:	parent node
629  * @prev:	previous child of the parent node, or NULL to get first
630  *
631  * Return: A node pointer with refcount incremented, use of_node_put() on
632  * it when done. Returns NULL when prev is the last child. Decrements the
633  * refcount of prev.
634  */
of_get_next_child(const struct device_node * node,struct device_node * prev)635 struct device_node *of_get_next_child(const struct device_node *node,
636 	struct device_node *prev)
637 {
638 	struct device_node *next;
639 	unsigned long flags;
640 
641 	raw_spin_lock_irqsave(&devtree_lock, flags);
642 	next = __of_get_next_child(node, prev);
643 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
644 	return next;
645 }
646 EXPORT_SYMBOL(of_get_next_child);
647 
648 /**
649  * of_get_next_child_with_prefix - Find the next child node with prefix
650  * @node:	parent node
651  * @prev:	previous child of the parent node, or NULL to get first
652  * @prefix:	prefix that the node name should have
653  *
654  * This function is like of_get_next_child(), except that it automatically
655  * skips any nodes whose name doesn't have the given prefix.
656  *
657  * Return: A node pointer with refcount incremented, use
658  * of_node_put() on it when done.
659  */
of_get_next_child_with_prefix(const struct device_node * node,struct device_node * prev,const char * prefix)660 struct device_node *of_get_next_child_with_prefix(const struct device_node *node,
661 						  struct device_node *prev,
662 						  const char *prefix)
663 {
664 	struct device_node *next;
665 	unsigned long flags;
666 
667 	if (!node)
668 		return NULL;
669 
670 	raw_spin_lock_irqsave(&devtree_lock, flags);
671 	next = prev ? prev->sibling : node->child;
672 	for (; next; next = next->sibling) {
673 		if (!of_node_name_prefix(next, prefix))
674 			continue;
675 		if (of_node_get(next))
676 			break;
677 	}
678 	of_node_put(prev);
679 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
680 	return next;
681 }
682 EXPORT_SYMBOL(of_get_next_child_with_prefix);
683 
of_get_next_status_child(const struct device_node * node,struct device_node * prev,bool (* checker)(const struct device_node *))684 static struct device_node *of_get_next_status_child(const struct device_node *node,
685 						    struct device_node *prev,
686 						    bool (*checker)(const struct device_node *))
687 {
688 	struct device_node *next;
689 	unsigned long flags;
690 
691 	if (!node)
692 		return NULL;
693 
694 	raw_spin_lock_irqsave(&devtree_lock, flags);
695 	next = prev ? prev->sibling : node->child;
696 	for (; next; next = next->sibling) {
697 		if (!checker(next))
698 			continue;
699 		if (of_node_get(next))
700 			break;
701 	}
702 	of_node_put(prev);
703 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
704 	return next;
705 }
706 
707 /**
708  * of_get_next_available_child - Find the next available child node
709  * @node:	parent node
710  * @prev:	previous child of the parent node, or NULL to get first
711  *
712  * This function is like of_get_next_child(), except that it
713  * automatically skips any disabled nodes (i.e. status = "disabled").
714  */
of_get_next_available_child(const struct device_node * node,struct device_node * prev)715 struct device_node *of_get_next_available_child(const struct device_node *node,
716 	struct device_node *prev)
717 {
718 	return of_get_next_status_child(node, prev, __of_device_is_available);
719 }
720 EXPORT_SYMBOL(of_get_next_available_child);
721 
722 /**
723  * of_get_next_reserved_child - Find the next reserved child node
724  * @node:	parent node
725  * @prev:	previous child of the parent node, or NULL to get first
726  *
727  * This function is like of_get_next_child(), except that it
728  * automatically skips any disabled nodes (i.e. status = "disabled").
729  */
of_get_next_reserved_child(const struct device_node * node,struct device_node * prev)730 struct device_node *of_get_next_reserved_child(const struct device_node *node,
731 						struct device_node *prev)
732 {
733 	return of_get_next_status_child(node, prev, __of_device_is_reserved);
734 }
735 EXPORT_SYMBOL(of_get_next_reserved_child);
736 
737 /**
738  * of_get_next_cpu_node - Iterate on cpu nodes
739  * @prev:	previous child of the /cpus node, or NULL to get first
740  *
741  * Unusable CPUs (those with the status property set to "fail" or "fail-...")
742  * will be skipped.
743  *
744  * Return: A cpu node pointer with refcount incremented, use of_node_put()
745  * on it when done. Returns NULL when prev is the last child. Decrements
746  * the refcount of prev.
747  */
of_get_next_cpu_node(struct device_node * prev)748 struct device_node *of_get_next_cpu_node(struct device_node *prev)
749 {
750 	struct device_node *next = NULL;
751 	unsigned long flags;
752 	struct device_node *node;
753 
754 	if (!prev)
755 		node = of_find_node_by_path("/cpus");
756 
757 	raw_spin_lock_irqsave(&devtree_lock, flags);
758 	if (prev)
759 		next = prev->sibling;
760 	else if (node) {
761 		next = node->child;
762 		of_node_put(node);
763 	}
764 	for (; next; next = next->sibling) {
765 		if (__of_device_is_fail(next))
766 			continue;
767 		if (!(of_node_name_eq(next, "cpu") ||
768 		      __of_node_is_type(next, "cpu")))
769 			continue;
770 		if (of_node_get(next))
771 			break;
772 	}
773 	of_node_put(prev);
774 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
775 	return next;
776 }
777 EXPORT_SYMBOL(of_get_next_cpu_node);
778 
779 /**
780  * of_get_compatible_child - Find compatible child node
781  * @parent:	parent node
782  * @compatible:	compatible string
783  *
784  * Lookup child node whose compatible property contains the given compatible
785  * string.
786  *
787  * Return: a node pointer with refcount incremented, use of_node_put() on it
788  * when done; or NULL if not found.
789  */
of_get_compatible_child(const struct device_node * parent,const char * compatible)790 struct device_node *of_get_compatible_child(const struct device_node *parent,
791 				const char *compatible)
792 {
793 	struct device_node *child;
794 
795 	for_each_child_of_node(parent, child) {
796 		if (of_device_is_compatible(child, compatible))
797 			break;
798 	}
799 
800 	return child;
801 }
802 EXPORT_SYMBOL(of_get_compatible_child);
803 
804 /**
805  * of_get_child_by_name - Find the child node by name for a given parent
806  * @node:	parent node
807  * @name:	child name to look for.
808  *
809  * This function looks for child node for given matching name
810  *
811  * Return: A node pointer if found, with refcount incremented, use
812  * of_node_put() on it when done.
813  * Returns NULL if node is not found.
814  */
of_get_child_by_name(const struct device_node * node,const char * name)815 struct device_node *of_get_child_by_name(const struct device_node *node,
816 				const char *name)
817 {
818 	struct device_node *child;
819 
820 	for_each_child_of_node(node, child)
821 		if (of_node_name_eq(child, name))
822 			break;
823 	return child;
824 }
825 EXPORT_SYMBOL(of_get_child_by_name);
826 
827 /**
828  * of_get_available_child_by_name - Find the available child node by name for a given parent
829  * @node:	parent node
830  * @name:	child name to look for.
831  *
832  * This function looks for child node for given matching name and checks the
833  * device's availability for use.
834  *
835  * Return: A node pointer if found, with refcount incremented, use
836  * of_node_put() on it when done.
837  * Returns NULL if node is not found.
838  */
of_get_available_child_by_name(const struct device_node * node,const char * name)839 struct device_node *of_get_available_child_by_name(const struct device_node *node,
840 						   const char *name)
841 {
842 	struct device_node *child;
843 
844 	child = of_get_child_by_name(node, name);
845 	if (child && !of_device_is_available(child)) {
846 		of_node_put(child);
847 		return NULL;
848 	}
849 
850 	return child;
851 }
852 EXPORT_SYMBOL(of_get_available_child_by_name);
853 
__of_find_node_by_path(const struct device_node * parent,const char * path)854 struct device_node *__of_find_node_by_path(const struct device_node *parent,
855 						const char *path)
856 {
857 	struct device_node *child;
858 	int len;
859 
860 	len = strcspn(path, "/:");
861 	if (!len)
862 		return NULL;
863 
864 	__for_each_child_of_node(parent, child) {
865 		const char *name = kbasename(child->full_name);
866 		if (strncmp(path, name, len) == 0 && (strlen(name) == len))
867 			return child;
868 	}
869 	return NULL;
870 }
871 
__of_find_node_by_full_path(struct device_node * node,const char * path)872 struct device_node *__of_find_node_by_full_path(struct device_node *node,
873 						const char *path)
874 {
875 	const char *separator = strchr(path, ':');
876 
877 	while (node && *path == '/') {
878 		struct device_node *tmp = node;
879 
880 		path++; /* Increment past '/' delimiter */
881 		node = __of_find_node_by_path(node, path);
882 		of_node_put(tmp);
883 		path = strchrnul(path, '/');
884 		if (separator && separator < path)
885 			break;
886 	}
887 	return node;
888 }
889 
890 /**
891  * of_find_node_opts_by_path - Find a node matching a full OF path
892  * @path: Either the full path to match, or if the path does not
893  *       start with '/', the name of a property of the /aliases
894  *       node (an alias).  In the case of an alias, the node
895  *       matching the alias' value will be returned.
896  * @opts: Address of a pointer into which to store the start of
897  *       an options string appended to the end of the path with
898  *       a ':' separator.
899  *
900  * Valid paths:
901  *  * /foo/bar	Full path
902  *  * foo	Valid alias
903  *  * foo/bar	Valid alias + relative path
904  *
905  * Return: A node pointer with refcount incremented, use
906  * of_node_put() on it when done.
907  */
of_find_node_opts_by_path(const char * path,const char ** opts)908 struct device_node *of_find_node_opts_by_path(const char *path, const char **opts)
909 {
910 	struct device_node *np = NULL;
911 	const struct property *pp;
912 	unsigned long flags;
913 	const char *separator = strchr(path, ':');
914 
915 	if (opts)
916 		*opts = separator ? separator + 1 : NULL;
917 
918 	if (strcmp(path, "/") == 0)
919 		return of_node_get(of_root);
920 
921 	/* The path could begin with an alias */
922 	if (*path != '/') {
923 		int len;
924 		const char *p = strchrnul(path, '/');
925 
926 		if (separator && separator < p)
927 			p = separator;
928 		len = p - path;
929 
930 		/* of_aliases must not be NULL */
931 		if (!of_aliases)
932 			return NULL;
933 
934 		for_each_property_of_node(of_aliases, pp) {
935 			if (strlen(pp->name) == len && !strncmp(pp->name, path, len)) {
936 				np = of_find_node_by_path(pp->value);
937 				break;
938 			}
939 		}
940 		if (!np)
941 			return NULL;
942 		path = p;
943 	}
944 
945 	/* Step down the tree matching path components */
946 	raw_spin_lock_irqsave(&devtree_lock, flags);
947 	if (!np)
948 		np = of_node_get(of_root);
949 	np = __of_find_node_by_full_path(np, path);
950 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
951 	return np;
952 }
953 EXPORT_SYMBOL(of_find_node_opts_by_path);
954 
955 /**
956  * of_find_node_by_name - Find a node by its "name" property
957  * @from:	The node to start searching from or NULL; the node
958  *		you pass will not be searched, only the next one
959  *		will. Typically, you pass what the previous call
960  *		returned. of_node_put() will be called on @from.
961  * @name:	The name string to match against
962  *
963  * Return: A node pointer with refcount incremented, use
964  * of_node_put() on it when done.
965  */
of_find_node_by_name(struct device_node * from,const char * name)966 struct device_node *of_find_node_by_name(struct device_node *from,
967 	const char *name)
968 {
969 	struct device_node *np;
970 	unsigned long flags;
971 
972 	raw_spin_lock_irqsave(&devtree_lock, flags);
973 	for_each_of_allnodes_from(from, np)
974 		if (of_node_name_eq(np, name) && of_node_get(np))
975 			break;
976 	of_node_put(from);
977 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
978 	return np;
979 }
980 EXPORT_SYMBOL(of_find_node_by_name);
981 
982 /**
983  * of_find_node_by_type - Find a node by its "device_type" property
984  * @from:	The node to start searching from, or NULL to start searching
985  *		the entire device tree. The node you pass will not be
986  *		searched, only the next one will; typically, you pass
987  *		what the previous call returned. of_node_put() will be
988  *		called on from for you.
989  * @type:	The type string to match against
990  *
991  * Return: A node pointer with refcount incremented, use
992  * of_node_put() on it when done.
993  */
of_find_node_by_type(struct device_node * from,const char * type)994 struct device_node *of_find_node_by_type(struct device_node *from,
995 	const char *type)
996 {
997 	struct device_node *np;
998 	unsigned long flags;
999 
1000 	raw_spin_lock_irqsave(&devtree_lock, flags);
1001 	for_each_of_allnodes_from(from, np)
1002 		if (__of_node_is_type(np, type) && of_node_get(np))
1003 			break;
1004 	of_node_put(from);
1005 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1006 	return np;
1007 }
1008 EXPORT_SYMBOL(of_find_node_by_type);
1009 
1010 /**
1011  * of_find_compatible_node - Find a node based on type and one of the
1012  *                                tokens in its "compatible" property
1013  * @from:	The node to start searching from or NULL, the node
1014  *		you pass will not be searched, only the next one
1015  *		will; typically, you pass what the previous call
1016  *		returned. of_node_put() will be called on it
1017  * @type:	The type string to match "device_type" or NULL to ignore
1018  * @compatible:	The string to match to one of the tokens in the device
1019  *		"compatible" list.
1020  *
1021  * Return: A node pointer with refcount incremented, use
1022  * of_node_put() on it when done.
1023  */
of_find_compatible_node(struct device_node * from,const char * type,const char * compatible)1024 struct device_node *of_find_compatible_node(struct device_node *from,
1025 	const char *type, const char *compatible)
1026 {
1027 	struct device_node *np;
1028 	unsigned long flags;
1029 
1030 	raw_spin_lock_irqsave(&devtree_lock, flags);
1031 	for_each_of_allnodes_from(from, np)
1032 		if (__of_device_is_compatible(np, compatible, type, NULL) &&
1033 		    of_node_get(np))
1034 			break;
1035 	of_node_put(from);
1036 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1037 	return np;
1038 }
1039 EXPORT_SYMBOL(of_find_compatible_node);
1040 
1041 /**
1042  * of_find_node_with_property - Find a node which has a property with
1043  *                              the given name.
1044  * @from:	The node to start searching from or NULL, the node
1045  *		you pass will not be searched, only the next one
1046  *		will; typically, you pass what the previous call
1047  *		returned. of_node_put() will be called on it
1048  * @prop_name:	The name of the property to look for.
1049  *
1050  * Return: A node pointer with refcount incremented, use
1051  * of_node_put() on it when done.
1052  */
of_find_node_with_property(struct device_node * from,const char * prop_name)1053 struct device_node *of_find_node_with_property(struct device_node *from,
1054 	const char *prop_name)
1055 {
1056 	struct device_node *np;
1057 	unsigned long flags;
1058 
1059 	raw_spin_lock_irqsave(&devtree_lock, flags);
1060 	for_each_of_allnodes_from(from, np) {
1061 		if (__of_find_property(np, prop_name, NULL)) {
1062 			of_node_get(np);
1063 			break;
1064 		}
1065 	}
1066 	of_node_put(from);
1067 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1068 	return np;
1069 }
1070 EXPORT_SYMBOL(of_find_node_with_property);
1071 
1072 static
__of_match_node(const struct of_device_id * matches,const struct device_node * node)1073 const struct of_device_id *__of_match_node(const struct of_device_id *matches,
1074 					   const struct device_node *node)
1075 {
1076 	const struct of_device_id *best_match = NULL;
1077 	int score, best_score = 0;
1078 
1079 	if (!matches)
1080 		return NULL;
1081 
1082 	for (; matches->name[0] || matches->type[0] || matches->compatible[0]; matches++) {
1083 		score = __of_device_is_compatible(node, matches->compatible,
1084 						  matches->type, matches->name);
1085 		if (score > best_score) {
1086 			best_match = matches;
1087 			best_score = score;
1088 		}
1089 	}
1090 
1091 	return best_match;
1092 }
1093 
1094 /**
1095  * of_match_node - Tell if a device_node has a matching of_match structure
1096  * @matches:	array of of device match structures to search in
1097  * @node:	the of device structure to match against
1098  *
1099  * Low level utility function used by device matching.
1100  */
of_match_node(const struct of_device_id * matches,const struct device_node * node)1101 const struct of_device_id *of_match_node(const struct of_device_id *matches,
1102 					 const struct device_node *node)
1103 {
1104 	const struct of_device_id *match;
1105 	unsigned long flags;
1106 
1107 	raw_spin_lock_irqsave(&devtree_lock, flags);
1108 	match = __of_match_node(matches, node);
1109 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1110 	return match;
1111 }
1112 EXPORT_SYMBOL(of_match_node);
1113 
1114 /**
1115  * of_find_matching_node_and_match - Find a node based on an of_device_id
1116  *				     match table.
1117  * @from:	The node to start searching from or NULL, the node
1118  *		you pass will not be searched, only the next one
1119  *		will; typically, you pass what the previous call
1120  *		returned. of_node_put() will be called on it
1121  * @matches:	array of of device match structures to search in
1122  * @match:	Updated to point at the matches entry which matched
1123  *
1124  * Return: A node pointer with refcount incremented, use
1125  * of_node_put() on it when done.
1126  */
of_find_matching_node_and_match(struct device_node * from,const struct of_device_id * matches,const struct of_device_id ** match)1127 struct device_node *of_find_matching_node_and_match(struct device_node *from,
1128 					const struct of_device_id *matches,
1129 					const struct of_device_id **match)
1130 {
1131 	struct device_node *np;
1132 	const struct of_device_id *m;
1133 	unsigned long flags;
1134 
1135 	if (match)
1136 		*match = NULL;
1137 
1138 	raw_spin_lock_irqsave(&devtree_lock, flags);
1139 	for_each_of_allnodes_from(from, np) {
1140 		m = __of_match_node(matches, np);
1141 		if (m && of_node_get(np)) {
1142 			if (match)
1143 				*match = m;
1144 			break;
1145 		}
1146 	}
1147 	of_node_put(from);
1148 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1149 	return np;
1150 }
1151 EXPORT_SYMBOL(of_find_matching_node_and_match);
1152 
1153 /**
1154  * of_alias_from_compatible - Lookup appropriate alias for a device node
1155  *			      depending on compatible
1156  * @node:	pointer to a device tree node
1157  * @alias:	Pointer to buffer that alias value will be copied into
1158  * @len:	Length of alias value
1159  *
1160  * Based on the value of the compatible property, this routine will attempt
1161  * to choose an appropriate alias value for a particular device tree node.
1162  * It does this by stripping the manufacturer prefix (as delimited by a ',')
1163  * from the first entry in the compatible list property.
1164  *
1165  * Note: The matching on just the "product" side of the compatible is a relic
1166  * from I2C and SPI. Please do not add any new user.
1167  *
1168  * Return: This routine returns 0 on success, <0 on failure.
1169  */
of_alias_from_compatible(const struct device_node * node,char * alias,int len)1170 int of_alias_from_compatible(const struct device_node *node, char *alias, int len)
1171 {
1172 	const char *compatible, *p;
1173 	int cplen;
1174 
1175 	compatible = of_get_property(node, "compatible", &cplen);
1176 	if (!compatible || strlen(compatible) > cplen)
1177 		return -ENODEV;
1178 	p = strchr(compatible, ',');
1179 	strscpy(alias, p ? p + 1 : compatible, len);
1180 	return 0;
1181 }
1182 EXPORT_SYMBOL_GPL(of_alias_from_compatible);
1183 
1184 /**
1185  * of_find_node_by_phandle - Find a node given a phandle
1186  * @handle:	phandle of the node to find
1187  *
1188  * Return: A node pointer with refcount incremented, use
1189  * of_node_put() on it when done.
1190  */
of_find_node_by_phandle(phandle handle)1191 struct device_node *of_find_node_by_phandle(phandle handle)
1192 {
1193 	struct device_node *np = NULL;
1194 	unsigned long flags;
1195 	u32 handle_hash;
1196 
1197 	if (!handle)
1198 		return NULL;
1199 
1200 	handle_hash = of_phandle_cache_hash(handle);
1201 
1202 	raw_spin_lock_irqsave(&devtree_lock, flags);
1203 
1204 	if (phandle_cache[handle_hash] &&
1205 	    handle == phandle_cache[handle_hash]->phandle)
1206 		np = phandle_cache[handle_hash];
1207 
1208 	if (!np) {
1209 		for_each_of_allnodes(np)
1210 			if (np->phandle == handle &&
1211 			    !of_node_check_flag(np, OF_DETACHED)) {
1212 				phandle_cache[handle_hash] = np;
1213 				break;
1214 			}
1215 	}
1216 
1217 	of_node_get(np);
1218 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1219 	return np;
1220 }
1221 EXPORT_SYMBOL(of_find_node_by_phandle);
1222 
of_print_phandle_args(const char * msg,const struct of_phandle_args * args)1223 void of_print_phandle_args(const char *msg, const struct of_phandle_args *args)
1224 {
1225 	int i;
1226 	printk("%s %pOF", msg, args->np);
1227 	for (i = 0; i < args->args_count; i++) {
1228 		const char delim = i ? ',' : ':';
1229 
1230 		pr_cont("%c%08x", delim, args->args[i]);
1231 	}
1232 	pr_cont("\n");
1233 }
1234 
of_phandle_iterator_init(struct of_phandle_iterator * it,const struct device_node * np,const char * list_name,const char * cells_name,int cell_count)1235 int of_phandle_iterator_init(struct of_phandle_iterator *it,
1236 		const struct device_node *np,
1237 		const char *list_name,
1238 		const char *cells_name,
1239 		int cell_count)
1240 {
1241 	const __be32 *list;
1242 	int size;
1243 
1244 	memset(it, 0, sizeof(*it));
1245 
1246 	/*
1247 	 * one of cell_count or cells_name must be provided to determine the
1248 	 * argument length.
1249 	 */
1250 	if (cell_count < 0 && !cells_name)
1251 		return -EINVAL;
1252 
1253 	list = of_get_property(np, list_name, &size);
1254 	if (!list)
1255 		return -ENOENT;
1256 
1257 	it->cells_name = cells_name;
1258 	it->cell_count = cell_count;
1259 	it->parent = np;
1260 	it->list_end = list + size / sizeof(*list);
1261 	it->phandle_end = list;
1262 	it->cur = list;
1263 
1264 	return 0;
1265 }
1266 EXPORT_SYMBOL_GPL(of_phandle_iterator_init);
1267 
of_phandle_iterator_next(struct of_phandle_iterator * it)1268 int of_phandle_iterator_next(struct of_phandle_iterator *it)
1269 {
1270 	uint32_t count = 0;
1271 
1272 	if (it->node) {
1273 		of_node_put(it->node);
1274 		it->node = NULL;
1275 	}
1276 
1277 	if (!it->cur || it->phandle_end >= it->list_end)
1278 		return -ENOENT;
1279 
1280 	it->cur = it->phandle_end;
1281 
1282 	/* If phandle is 0, then it is an empty entry with no arguments. */
1283 	it->phandle = be32_to_cpup(it->cur++);
1284 
1285 	if (it->phandle) {
1286 
1287 		/*
1288 		 * Find the provider node and parse the #*-cells property to
1289 		 * determine the argument length.
1290 		 */
1291 		it->node = of_find_node_by_phandle(it->phandle);
1292 
1293 		if (it->cells_name) {
1294 			if (!it->node) {
1295 				pr_err("%pOF: could not find phandle %d\n",
1296 				       it->parent, it->phandle);
1297 				goto err;
1298 			}
1299 
1300 			if (of_property_read_u32(it->node, it->cells_name,
1301 						 &count)) {
1302 				/*
1303 				 * If both cell_count and cells_name is given,
1304 				 * fall back to cell_count in absence
1305 				 * of the cells_name property
1306 				 */
1307 				if (it->cell_count >= 0) {
1308 					count = it->cell_count;
1309 				} else {
1310 					pr_err("%pOF: could not get %s for %pOF\n",
1311 					       it->parent,
1312 					       it->cells_name,
1313 					       it->node);
1314 					goto err;
1315 				}
1316 			}
1317 		} else {
1318 			count = it->cell_count;
1319 		}
1320 
1321 		/*
1322 		 * Make sure that the arguments actually fit in the remaining
1323 		 * property data length
1324 		 */
1325 		if (it->cur + count > it->list_end) {
1326 			if (it->cells_name)
1327 				pr_err("%pOF: %s = %d found %td\n",
1328 					it->parent, it->cells_name,
1329 					count, it->list_end - it->cur);
1330 			else
1331 				pr_err("%pOF: phandle %s needs %d, found %td\n",
1332 					it->parent, of_node_full_name(it->node),
1333 					count, it->list_end - it->cur);
1334 			goto err;
1335 		}
1336 	}
1337 
1338 	it->phandle_end = it->cur + count;
1339 	it->cur_count = count;
1340 
1341 	return 0;
1342 
1343 err:
1344 	if (it->node) {
1345 		of_node_put(it->node);
1346 		it->node = NULL;
1347 	}
1348 
1349 	return -EINVAL;
1350 }
1351 EXPORT_SYMBOL_GPL(of_phandle_iterator_next);
1352 
of_phandle_iterator_args(struct of_phandle_iterator * it,uint32_t * args,int size)1353 int of_phandle_iterator_args(struct of_phandle_iterator *it,
1354 			     uint32_t *args,
1355 			     int size)
1356 {
1357 	int i, count;
1358 
1359 	count = it->cur_count;
1360 
1361 	if (WARN_ON(size < count))
1362 		count = size;
1363 
1364 	for (i = 0; i < count; i++)
1365 		args[i] = be32_to_cpup(it->cur++);
1366 
1367 	return count;
1368 }
1369 
__of_parse_phandle_with_args(const struct device_node * np,const char * list_name,const char * cells_name,int cell_count,int index,struct of_phandle_args * out_args)1370 int __of_parse_phandle_with_args(const struct device_node *np,
1371 				 const char *list_name,
1372 				 const char *cells_name,
1373 				 int cell_count, int index,
1374 				 struct of_phandle_args *out_args)
1375 {
1376 	struct of_phandle_iterator it;
1377 	int rc, cur_index = 0;
1378 
1379 	if (index < 0)
1380 		return -EINVAL;
1381 
1382 	/* Loop over the phandles until all the requested entry is found */
1383 	of_for_each_phandle(&it, rc, np, list_name, cells_name, cell_count) {
1384 		/*
1385 		 * All of the error cases bail out of the loop, so at
1386 		 * this point, the parsing is successful. If the requested
1387 		 * index matches, then fill the out_args structure and return,
1388 		 * or return -ENOENT for an empty entry.
1389 		 */
1390 		rc = -ENOENT;
1391 		if (cur_index == index) {
1392 			if (!it.phandle)
1393 				goto err;
1394 
1395 			if (out_args) {
1396 				int c;
1397 
1398 				c = of_phandle_iterator_args(&it,
1399 							     out_args->args,
1400 							     MAX_PHANDLE_ARGS);
1401 				out_args->np = it.node;
1402 				out_args->args_count = c;
1403 			} else {
1404 				of_node_put(it.node);
1405 			}
1406 
1407 			/* Found it! return success */
1408 			return 0;
1409 		}
1410 
1411 		cur_index++;
1412 	}
1413 
1414 	/*
1415 	 * Unlock node before returning result; will be one of:
1416 	 * -ENOENT : index is for empty phandle
1417 	 * -EINVAL : parsing error on data
1418 	 */
1419 
1420  err:
1421 	of_node_put(it.node);
1422 	return rc;
1423 }
1424 EXPORT_SYMBOL(__of_parse_phandle_with_args);
1425 
1426 /**
1427  * of_parse_phandle_with_args_map() - Find a node pointed by phandle in a list and remap it
1428  * @np:		pointer to a device tree node containing a list
1429  * @list_name:	property name that contains a list
1430  * @stem_name:	stem of property names that specify phandles' arguments count
1431  * @index:	index of a phandle to parse out
1432  * @out_args:	optional pointer to output arguments structure (will be filled)
1433  *
1434  * This function is useful to parse lists of phandles and their arguments.
1435  * Returns 0 on success and fills out_args, on error returns appropriate errno
1436  * value. The difference between this function and of_parse_phandle_with_args()
1437  * is that this API remaps a phandle if the node the phandle points to has
1438  * a <@stem_name>-map property.
1439  *
1440  * Caller is responsible to call of_node_put() on the returned out_args->np
1441  * pointer.
1442  *
1443  * Example::
1444  *
1445  *  phandle1: node1 {
1446  *  	#list-cells = <2>;
1447  *  };
1448  *
1449  *  phandle2: node2 {
1450  *  	#list-cells = <1>;
1451  *  };
1452  *
1453  *  phandle3: node3 {
1454  *  	#list-cells = <1>;
1455  *  	list-map = <0 &phandle2 3>,
1456  *  		   <1 &phandle2 2>,
1457  *  		   <2 &phandle1 5 1>;
1458  *  	list-map-mask = <0x3>;
1459  *  };
1460  *
1461  *  node4 {
1462  *  	list = <&phandle1 1 2 &phandle3 0>;
1463  *  };
1464  *
1465  * To get a device_node of the ``node2`` node you may call this:
1466  * of_parse_phandle_with_args(node4, "list", "list", 1, &args);
1467  */
of_parse_phandle_with_args_map(const struct device_node * np,const char * list_name,const char * stem_name,int index,struct of_phandle_args * out_args)1468 int of_parse_phandle_with_args_map(const struct device_node *np,
1469 				   const char *list_name,
1470 				   const char *stem_name,
1471 				   int index, struct of_phandle_args *out_args)
1472 {
1473 	char *cells_name __free(kfree) = kasprintf(GFP_KERNEL, "#%s-cells", stem_name);
1474 	char *map_name __free(kfree) = kasprintf(GFP_KERNEL, "%s-map", stem_name);
1475 	char *mask_name __free(kfree) = kasprintf(GFP_KERNEL, "%s-map-mask", stem_name);
1476 	char *pass_name __free(kfree) = kasprintf(GFP_KERNEL, "%s-map-pass-thru", stem_name);
1477 	struct device_node *cur, *new = NULL;
1478 	const __be32 *map, *mask, *pass;
1479 	static const __be32 dummy_mask[] = { [0 ... (MAX_PHANDLE_ARGS - 1)] = cpu_to_be32(~0) };
1480 	static const __be32 dummy_pass[] = { [0 ... (MAX_PHANDLE_ARGS - 1)] = cpu_to_be32(0) };
1481 	__be32 initial_match_array[MAX_PHANDLE_ARGS];
1482 	const __be32 *match_array = initial_match_array;
1483 	int i, ret, map_len, match;
1484 	u32 list_size, new_size;
1485 
1486 	if (index < 0)
1487 		return -EINVAL;
1488 
1489 	if (!cells_name || !map_name || !mask_name || !pass_name)
1490 		return -ENOMEM;
1491 
1492 	ret = __of_parse_phandle_with_args(np, list_name, cells_name, -1, index,
1493 					   out_args);
1494 	if (ret)
1495 		return ret;
1496 
1497 	/* Get the #<list>-cells property */
1498 	cur = out_args->np;
1499 	ret = of_property_read_u32(cur, cells_name, &list_size);
1500 	if (ret < 0)
1501 		goto put;
1502 
1503 	/* Precalculate the match array - this simplifies match loop */
1504 	for (i = 0; i < list_size; i++)
1505 		initial_match_array[i] = cpu_to_be32(out_args->args[i]);
1506 
1507 	ret = -EINVAL;
1508 	while (cur) {
1509 		/* Get the <list>-map property */
1510 		map = of_get_property(cur, map_name, &map_len);
1511 		if (!map) {
1512 			return 0;
1513 		}
1514 		map_len /= sizeof(u32);
1515 
1516 		/* Get the <list>-map-mask property (optional) */
1517 		mask = of_get_property(cur, mask_name, NULL);
1518 		if (!mask)
1519 			mask = dummy_mask;
1520 		/* Iterate through <list>-map property */
1521 		match = 0;
1522 		while (map_len > (list_size + 1) && !match) {
1523 			/* Compare specifiers */
1524 			match = 1;
1525 			for (i = 0; i < list_size; i++, map_len--)
1526 				match &= !((match_array[i] ^ *map++) & mask[i]);
1527 
1528 			of_node_put(new);
1529 			new = of_find_node_by_phandle(be32_to_cpup(map));
1530 			map++;
1531 			map_len--;
1532 
1533 			/* Check if not found */
1534 			if (!new) {
1535 				ret = -EINVAL;
1536 				goto put;
1537 			}
1538 
1539 			if (!of_device_is_available(new))
1540 				match = 0;
1541 
1542 			ret = of_property_read_u32(new, cells_name, &new_size);
1543 			if (ret)
1544 				goto put;
1545 
1546 			/* Check for malformed properties */
1547 			if (WARN_ON(new_size > MAX_PHANDLE_ARGS) ||
1548 			    map_len < new_size) {
1549 				ret = -EINVAL;
1550 				goto put;
1551 			}
1552 
1553 			/* Move forward by new node's #<list>-cells amount */
1554 			map += new_size;
1555 			map_len -= new_size;
1556 		}
1557 		if (!match) {
1558 			ret = -ENOENT;
1559 			goto put;
1560 		}
1561 
1562 		/* Get the <list>-map-pass-thru property (optional) */
1563 		pass = of_get_property(cur, pass_name, NULL);
1564 		if (!pass)
1565 			pass = dummy_pass;
1566 
1567 		/*
1568 		 * Successfully parsed a <list>-map translation; copy new
1569 		 * specifier into the out_args structure, keeping the
1570 		 * bits specified in <list>-map-pass-thru.
1571 		 */
1572 		for (i = 0; i < new_size; i++) {
1573 			__be32 val = *(map - new_size + i);
1574 
1575 			if (i < list_size) {
1576 				val &= ~pass[i];
1577 				val |= cpu_to_be32(out_args->args[i]) & pass[i];
1578 			}
1579 
1580 			initial_match_array[i] = val;
1581 			out_args->args[i] = be32_to_cpu(val);
1582 		}
1583 		out_args->args_count = list_size = new_size;
1584 		/* Iterate again with new provider */
1585 		out_args->np = new;
1586 		of_node_put(cur);
1587 		cur = new;
1588 		new = NULL;
1589 	}
1590 put:
1591 	of_node_put(cur);
1592 	of_node_put(new);
1593 	return ret;
1594 }
1595 EXPORT_SYMBOL(of_parse_phandle_with_args_map);
1596 
1597 /**
1598  * of_count_phandle_with_args() - Find the number of phandles references in a property
1599  * @np:		pointer to a device tree node containing a list
1600  * @list_name:	property name that contains a list
1601  * @cells_name:	property name that specifies phandles' arguments count
1602  *
1603  * Return: The number of phandle + argument tuples within a property. It
1604  * is a typical pattern to encode a list of phandle and variable
1605  * arguments into a single property. The number of arguments is encoded
1606  * by a property in the phandle-target node. For example, a gpios
1607  * property would contain a list of GPIO specifies consisting of a
1608  * phandle and 1 or more arguments. The number of arguments are
1609  * determined by the #gpio-cells property in the node pointed to by the
1610  * phandle.
1611  */
of_count_phandle_with_args(const struct device_node * np,const char * list_name,const char * cells_name)1612 int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
1613 				const char *cells_name)
1614 {
1615 	struct of_phandle_iterator it;
1616 	int rc, cur_index = 0;
1617 
1618 	/*
1619 	 * If cells_name is NULL we assume a cell count of 0. This makes
1620 	 * counting the phandles trivial as each 32bit word in the list is a
1621 	 * phandle and no arguments are to consider. So we don't iterate through
1622 	 * the list but just use the length to determine the phandle count.
1623 	 */
1624 	if (!cells_name) {
1625 		const __be32 *list;
1626 		int size;
1627 
1628 		list = of_get_property(np, list_name, &size);
1629 		if (!list)
1630 			return -ENOENT;
1631 
1632 		return size / sizeof(*list);
1633 	}
1634 
1635 	rc = of_phandle_iterator_init(&it, np, list_name, cells_name, -1);
1636 	if (rc)
1637 		return rc;
1638 
1639 	while ((rc = of_phandle_iterator_next(&it)) == 0)
1640 		cur_index += 1;
1641 
1642 	if (rc != -ENOENT)
1643 		return rc;
1644 
1645 	return cur_index;
1646 }
1647 EXPORT_SYMBOL(of_count_phandle_with_args);
1648 
__of_remove_property_from_list(struct property ** list,struct property * prop)1649 static struct property *__of_remove_property_from_list(struct property **list, struct property *prop)
1650 {
1651 	struct property **next;
1652 
1653 	for (next = list; *next; next = &(*next)->next) {
1654 		if (*next == prop) {
1655 			*next = prop->next;
1656 			prop->next = NULL;
1657 			return prop;
1658 		}
1659 	}
1660 	return NULL;
1661 }
1662 
1663 /**
1664  * __of_add_property - Add a property to a node without lock operations
1665  * @np:		Caller's Device Node
1666  * @prop:	Property to add
1667  */
__of_add_property(struct device_node * np,struct property * prop)1668 int __of_add_property(struct device_node *np, struct property *prop)
1669 {
1670 	int rc = 0;
1671 	unsigned long flags;
1672 	struct property **next;
1673 
1674 	raw_spin_lock_irqsave(&devtree_lock, flags);
1675 
1676 	__of_remove_property_from_list(&np->deadprops, prop);
1677 
1678 	prop->next = NULL;
1679 	next = &np->properties;
1680 	while (*next) {
1681 		if (of_prop_cmp(prop->name, (*next)->name) == 0) {
1682 			/* duplicate ! don't insert it */
1683 			rc = -EEXIST;
1684 			goto out_unlock;
1685 		}
1686 		next = &(*next)->next;
1687 	}
1688 	*next = prop;
1689 
1690 out_unlock:
1691 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1692 	if (rc)
1693 		return rc;
1694 
1695 	__of_add_property_sysfs(np, prop);
1696 	return 0;
1697 }
1698 
1699 /**
1700  * of_add_property - Add a property to a node
1701  * @np:		Caller's Device Node
1702  * @prop:	Property to add
1703  */
of_add_property(struct device_node * np,struct property * prop)1704 int of_add_property(struct device_node *np, struct property *prop)
1705 {
1706 	int rc;
1707 
1708 	mutex_lock(&of_mutex);
1709 	rc = __of_add_property(np, prop);
1710 	mutex_unlock(&of_mutex);
1711 
1712 	if (!rc)
1713 		of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop, NULL);
1714 
1715 	return rc;
1716 }
1717 EXPORT_SYMBOL_GPL(of_add_property);
1718 
__of_remove_property(struct device_node * np,struct property * prop)1719 int __of_remove_property(struct device_node *np, struct property *prop)
1720 {
1721 	unsigned long flags;
1722 	int rc = -ENODEV;
1723 
1724 	raw_spin_lock_irqsave(&devtree_lock, flags);
1725 
1726 	if (__of_remove_property_from_list(&np->properties, prop)) {
1727 		/* Found the property, add it to deadprops list */
1728 		prop->next = np->deadprops;
1729 		np->deadprops = prop;
1730 		rc = 0;
1731 	}
1732 
1733 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1734 	if (rc)
1735 		return rc;
1736 
1737 	__of_remove_property_sysfs(np, prop);
1738 	return 0;
1739 }
1740 
1741 /**
1742  * of_remove_property - Remove a property from a node.
1743  * @np:		Caller's Device Node
1744  * @prop:	Property to remove
1745  *
1746  * Note that we don't actually remove it, since we have given out
1747  * who-knows-how-many pointers to the data using get-property.
1748  * Instead we just move the property to the "dead properties"
1749  * list, so it won't be found any more.
1750  */
of_remove_property(struct device_node * np,struct property * prop)1751 int of_remove_property(struct device_node *np, struct property *prop)
1752 {
1753 	int rc;
1754 
1755 	if (!prop)
1756 		return -ENODEV;
1757 
1758 	mutex_lock(&of_mutex);
1759 	rc = __of_remove_property(np, prop);
1760 	mutex_unlock(&of_mutex);
1761 
1762 	if (!rc)
1763 		of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop, NULL);
1764 
1765 	return rc;
1766 }
1767 EXPORT_SYMBOL_GPL(of_remove_property);
1768 
__of_update_property(struct device_node * np,struct property * newprop,struct property ** oldpropp)1769 int __of_update_property(struct device_node *np, struct property *newprop,
1770 		struct property **oldpropp)
1771 {
1772 	struct property **next, *oldprop;
1773 	unsigned long flags;
1774 
1775 	raw_spin_lock_irqsave(&devtree_lock, flags);
1776 
1777 	__of_remove_property_from_list(&np->deadprops, newprop);
1778 
1779 	for (next = &np->properties; *next; next = &(*next)->next) {
1780 		if (of_prop_cmp((*next)->name, newprop->name) == 0)
1781 			break;
1782 	}
1783 	*oldpropp = oldprop = *next;
1784 
1785 	if (oldprop) {
1786 		/* replace the node */
1787 		newprop->next = oldprop->next;
1788 		*next = newprop;
1789 		oldprop->next = np->deadprops;
1790 		np->deadprops = oldprop;
1791 	} else {
1792 		/* new node */
1793 		newprop->next = NULL;
1794 		*next = newprop;
1795 	}
1796 
1797 	raw_spin_unlock_irqrestore(&devtree_lock, flags);
1798 
1799 	__of_update_property_sysfs(np, newprop, oldprop);
1800 
1801 	return 0;
1802 }
1803 
1804 /*
1805  * of_update_property - Update a property in a node, if the property does
1806  * not exist, add it.
1807  *
1808  * Note that we don't actually remove it, since we have given out
1809  * who-knows-how-many pointers to the data using get-property.
1810  * Instead we just move the property to the "dead properties" list,
1811  * and add the new property to the property list
1812  */
of_update_property(struct device_node * np,struct property * newprop)1813 int of_update_property(struct device_node *np, struct property *newprop)
1814 {
1815 	struct property *oldprop;
1816 	int rc;
1817 
1818 	if (!newprop->name)
1819 		return -EINVAL;
1820 
1821 	mutex_lock(&of_mutex);
1822 	rc = __of_update_property(np, newprop, &oldprop);
1823 	mutex_unlock(&of_mutex);
1824 
1825 	if (!rc)
1826 		of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop, oldprop);
1827 
1828 	return rc;
1829 }
1830 
of_alias_add(struct alias_prop * ap,struct device_node * np,int id,const char * stem,int stem_len)1831 static void of_alias_add(struct alias_prop *ap, struct device_node *np,
1832 			 int id, const char *stem, int stem_len)
1833 {
1834 	ap->np = np;
1835 	ap->id = id;
1836 	strscpy(ap->stem, stem, stem_len + 1);
1837 	list_add_tail(&ap->link, &aliases_lookup);
1838 	pr_debug("adding DT alias:%s: stem=%s id=%i node=%pOF\n",
1839 		 ap->alias, ap->stem, ap->id, np);
1840 }
1841 
1842 /**
1843  * of_alias_scan - Scan all properties of the 'aliases' node
1844  * @dt_alloc:	An allocator that provides a virtual address to memory
1845  *		for storing the resulting tree
1846  *
1847  * The function scans all the properties of the 'aliases' node and populates
1848  * the global lookup table with the properties.
1849  */
of_alias_scan(void * (* dt_alloc)(u64 size,u64 align))1850 void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
1851 {
1852 	const struct property *pp;
1853 
1854 	of_aliases = of_find_node_by_path("/aliases");
1855 	of_chosen = of_find_node_by_path("/chosen");
1856 	if (of_chosen == NULL)
1857 		of_chosen = of_find_node_by_path("/chosen@0");
1858 
1859 	if (of_chosen) {
1860 		/* linux,stdout-path and /aliases/stdout are for legacy compatibility */
1861 		const char *name = NULL;
1862 
1863 		if (of_property_read_string(of_chosen, "stdout-path", &name))
1864 			of_property_read_string(of_chosen, "linux,stdout-path",
1865 						&name);
1866 		if (IS_ENABLED(CONFIG_PPC) && !name)
1867 			of_property_read_string(of_aliases, "stdout", &name);
1868 		if (name)
1869 			of_stdout = of_find_node_opts_by_path(name, &of_stdout_options);
1870 		if (of_stdout)
1871 			of_stdout->fwnode.flags |= FWNODE_FLAG_BEST_EFFORT;
1872 	}
1873 
1874 	if (!of_aliases)
1875 		return;
1876 
1877 	for_each_property_of_node(of_aliases, pp) {
1878 		const char *start = pp->name;
1879 		const char *end = start + strlen(start);
1880 		struct device_node *np;
1881 		struct alias_prop *ap;
1882 		int id, len;
1883 
1884 		/* Skip those we do not want to proceed */
1885 		if (is_pseudo_property(pp->name))
1886 			continue;
1887 
1888 		np = of_find_node_by_path(pp->value);
1889 		if (!np)
1890 			continue;
1891 
1892 		/* walk the alias backwards to extract the id and work out
1893 		 * the 'stem' string */
1894 		while (isdigit(*(end-1)) && end > start)
1895 			end--;
1896 		len = end - start;
1897 
1898 		if (kstrtoint(end, 10, &id) < 0)
1899 			continue;
1900 
1901 		/* Allocate an alias_prop with enough space for the stem */
1902 		ap = dt_alloc(sizeof(*ap) + len + 1, __alignof__(*ap));
1903 		if (!ap)
1904 			continue;
1905 		memset(ap, 0, sizeof(*ap) + len + 1);
1906 		ap->alias = start;
1907 		of_alias_add(ap, np, id, start, len);
1908 	}
1909 }
1910 
1911 /**
1912  * of_alias_get_id - Get alias id for the given device_node
1913  * @np:		Pointer to the given device_node
1914  * @stem:	Alias stem of the given device_node
1915  *
1916  * The function travels the lookup table to get the alias id for the given
1917  * device_node and alias stem.
1918  *
1919  * Return: The alias id if found.
1920  */
of_alias_get_id(const struct device_node * np,const char * stem)1921 int of_alias_get_id(const struct device_node *np, const char *stem)
1922 {
1923 	struct alias_prop *app;
1924 	int id = -ENODEV;
1925 
1926 	mutex_lock(&of_mutex);
1927 	list_for_each_entry(app, &aliases_lookup, link) {
1928 		if (strcmp(app->stem, stem) != 0)
1929 			continue;
1930 
1931 		if (np == app->np) {
1932 			id = app->id;
1933 			break;
1934 		}
1935 	}
1936 	mutex_unlock(&of_mutex);
1937 
1938 	return id;
1939 }
1940 EXPORT_SYMBOL_GPL(of_alias_get_id);
1941 
1942 /**
1943  * of_alias_get_highest_id - Get highest alias id for the given stem
1944  * @stem:	Alias stem to be examined
1945  *
1946  * The function travels the lookup table to get the highest alias id for the
1947  * given alias stem.  It returns the alias id if found.
1948  */
of_alias_get_highest_id(const char * stem)1949 int of_alias_get_highest_id(const char *stem)
1950 {
1951 	struct alias_prop *app;
1952 	int id = -ENODEV;
1953 
1954 	mutex_lock(&of_mutex);
1955 	list_for_each_entry(app, &aliases_lookup, link) {
1956 		if (strcmp(app->stem, stem) != 0)
1957 			continue;
1958 
1959 		if (app->id > id)
1960 			id = app->id;
1961 	}
1962 	mutex_unlock(&of_mutex);
1963 
1964 	return id;
1965 }
1966 EXPORT_SYMBOL_GPL(of_alias_get_highest_id);
1967 
1968 /**
1969  * of_console_check() - Test and setup console for DT setup
1970  * @dn: Pointer to device node
1971  * @name: Name to use for preferred console without index. ex. "ttyS"
1972  * @index: Index to use for preferred console.
1973  *
1974  * Check if the given device node matches the stdout-path property in the
1975  * /chosen node. If it does then register it as the preferred console.
1976  *
1977  * Return: TRUE if console successfully setup. Otherwise return FALSE.
1978  */
of_console_check(const struct device_node * dn,char * name,int index)1979 bool of_console_check(const struct device_node *dn, char *name, int index)
1980 {
1981 	if (!dn || dn != of_stdout || console_set_on_cmdline)
1982 		return false;
1983 
1984 	/*
1985 	 * XXX: cast `options' to char pointer to suppress complication
1986 	 * warnings: printk, UART and console drivers expect char pointer.
1987 	 */
1988 	return !add_preferred_console(name, index, (char *)of_stdout_options);
1989 }
1990 EXPORT_SYMBOL_GPL(of_console_check);
1991 
1992 /**
1993  * of_find_next_cache_node - Find a node's subsidiary cache
1994  * @np:	node of type "cpu" or "cache"
1995  *
1996  * Return: A node pointer with refcount incremented, use
1997  * of_node_put() on it when done.  Caller should hold a reference
1998  * to np.
1999  */
of_find_next_cache_node(const struct device_node * np)2000 struct device_node *of_find_next_cache_node(const struct device_node *np)
2001 {
2002 	struct device_node *child, *cache_node;
2003 
2004 	cache_node = of_parse_phandle(np, "l2-cache", 0);
2005 	if (!cache_node)
2006 		cache_node = of_parse_phandle(np, "next-level-cache", 0);
2007 
2008 	if (cache_node)
2009 		return cache_node;
2010 
2011 	/* OF on pmac has nodes instead of properties named "l2-cache"
2012 	 * beneath CPU nodes.
2013 	 */
2014 	if (IS_ENABLED(CONFIG_PPC_PMAC) && of_node_is_type(np, "cpu"))
2015 		for_each_child_of_node(np, child)
2016 			if (of_node_is_type(child, "cache"))
2017 				return child;
2018 
2019 	return NULL;
2020 }
2021 
2022 /**
2023  * of_find_last_cache_level - Find the level at which the last cache is
2024  * 		present for the given logical cpu
2025  *
2026  * @cpu: cpu number(logical index) for which the last cache level is needed
2027  *
2028  * Return: The level at which the last cache is present. It is exactly
2029  * same as  the total number of cache levels for the given logical cpu.
2030  */
of_find_last_cache_level(unsigned int cpu)2031 int of_find_last_cache_level(unsigned int cpu)
2032 {
2033 	u32 cache_level = 0;
2034 	struct device_node *prev = NULL, *np = of_cpu_device_node_get(cpu);
2035 
2036 	while (np) {
2037 		of_node_put(prev);
2038 		prev = np;
2039 		np = of_find_next_cache_node(np);
2040 	}
2041 
2042 	of_property_read_u32(prev, "cache-level", &cache_level);
2043 	of_node_put(prev);
2044 
2045 	return cache_level;
2046 }
2047 
2048 /**
2049  * of_map_id - Translate an ID through a downstream mapping.
2050  * @np: root complex device node.
2051  * @id: device ID to map.
2052  * @map_name: property name of the map to use.
2053  * @map_mask_name: optional property name of the mask to use.
2054  * @target: optional pointer to a target device node.
2055  * @id_out: optional pointer to receive the translated ID.
2056  *
2057  * Given a device ID, look up the appropriate implementation-defined
2058  * platform ID and/or the target device which receives transactions on that
2059  * ID, as per the "iommu-map" and "msi-map" bindings. Either of @target or
2060  * @id_out may be NULL if only the other is required. If @target points to
2061  * a non-NULL device node pointer, only entries targeting that node will be
2062  * matched; if it points to a NULL value, it will receive the device node of
2063  * the first matching target phandle, with a reference held.
2064  *
2065  * Return: 0 on success or a standard error code on failure.
2066  */
of_map_id(const struct device_node * np,u32 id,const char * map_name,const char * map_mask_name,struct device_node ** target,u32 * id_out)2067 int of_map_id(const struct device_node *np, u32 id,
2068 	       const char *map_name, const char *map_mask_name,
2069 	       struct device_node **target, u32 *id_out)
2070 {
2071 	u32 map_mask, masked_id;
2072 	int map_len;
2073 	const __be32 *map = NULL;
2074 
2075 	if (!np || !map_name || (!target && !id_out))
2076 		return -EINVAL;
2077 
2078 	map = of_get_property(np, map_name, &map_len);
2079 	if (!map) {
2080 		if (target)
2081 			return -ENODEV;
2082 		/* Otherwise, no map implies no translation */
2083 		*id_out = id;
2084 		return 0;
2085 	}
2086 
2087 	if (!map_len || map_len % (4 * sizeof(*map))) {
2088 		pr_err("%pOF: Error: Bad %s length: %d\n", np,
2089 			map_name, map_len);
2090 		return -EINVAL;
2091 	}
2092 
2093 	/* The default is to select all bits. */
2094 	map_mask = 0xffffffff;
2095 
2096 	/*
2097 	 * Can be overridden by "{iommu,msi}-map-mask" property.
2098 	 * If of_property_read_u32() fails, the default is used.
2099 	 */
2100 	if (map_mask_name)
2101 		of_property_read_u32(np, map_mask_name, &map_mask);
2102 
2103 	masked_id = map_mask & id;
2104 	for ( ; map_len > 0; map_len -= 4 * sizeof(*map), map += 4) {
2105 		struct device_node *phandle_node;
2106 		u32 id_base = be32_to_cpup(map + 0);
2107 		u32 phandle = be32_to_cpup(map + 1);
2108 		u32 out_base = be32_to_cpup(map + 2);
2109 		u32 id_len = be32_to_cpup(map + 3);
2110 
2111 		if (id_base & ~map_mask) {
2112 			pr_err("%pOF: Invalid %s translation - %s-mask (0x%x) ignores id-base (0x%x)\n",
2113 				np, map_name, map_name,
2114 				map_mask, id_base);
2115 			return -EFAULT;
2116 		}
2117 
2118 		if (masked_id < id_base || masked_id >= id_base + id_len)
2119 			continue;
2120 
2121 		phandle_node = of_find_node_by_phandle(phandle);
2122 		if (!phandle_node)
2123 			return -ENODEV;
2124 
2125 		if (target) {
2126 			if (*target)
2127 				of_node_put(phandle_node);
2128 			else
2129 				*target = phandle_node;
2130 
2131 			if (*target != phandle_node)
2132 				continue;
2133 		}
2134 
2135 		if (id_out)
2136 			*id_out = masked_id - id_base + out_base;
2137 
2138 		pr_debug("%pOF: %s, using mask %08x, id-base: %08x, out-base: %08x, length: %08x, id: %08x -> %08x\n",
2139 			np, map_name, map_mask, id_base, out_base,
2140 			id_len, id, masked_id - id_base + out_base);
2141 		return 0;
2142 	}
2143 
2144 	pr_info("%pOF: no %s translation for id 0x%x on %pOF\n", np, map_name,
2145 		id, target && *target ? *target : NULL);
2146 
2147 	/* Bypasses translation */
2148 	if (id_out)
2149 		*id_out = id;
2150 	return 0;
2151 }
2152 EXPORT_SYMBOL_GPL(of_map_id);
2153