xref: /openbmc/linux/drivers/of/fdt.c (revision 54cbac81)
1 /*
2  * Functions for working with the Flattened Device Tree data format
3  *
4  * Copyright 2009 Benjamin Herrenschmidt, IBM Corp
5  * benh@kernel.crashing.org
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License
9  * version 2 as published by the Free Software Foundation.
10  */
11 
12 #include <linux/kernel.h>
13 #include <linux/initrd.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16 #include <linux/of_fdt.h>
17 #include <linux/string.h>
18 #include <linux/errno.h>
19 #include <linux/slab.h>
20 
21 #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
22 #ifdef CONFIG_PPC
23 #include <asm/machdep.h>
24 #endif /* CONFIG_PPC */
25 
26 #include <asm/page.h>
27 
28 char *of_fdt_get_string(struct boot_param_header *blob, u32 offset)
29 {
30 	return ((char *)blob) +
31 		be32_to_cpu(blob->off_dt_strings) + offset;
32 }
33 
34 /**
35  * of_fdt_get_property - Given a node in the given flat blob, return
36  * the property ptr
37  */
38 void *of_fdt_get_property(struct boot_param_header *blob,
39 		       unsigned long node, const char *name,
40 		       unsigned long *size)
41 {
42 	unsigned long p = node;
43 
44 	do {
45 		u32 tag = be32_to_cpup((__be32 *)p);
46 		u32 sz, noff;
47 		const char *nstr;
48 
49 		p += 4;
50 		if (tag == OF_DT_NOP)
51 			continue;
52 		if (tag != OF_DT_PROP)
53 			return NULL;
54 
55 		sz = be32_to_cpup((__be32 *)p);
56 		noff = be32_to_cpup((__be32 *)(p + 4));
57 		p += 8;
58 		if (be32_to_cpu(blob->version) < 0x10)
59 			p = ALIGN(p, sz >= 8 ? 8 : 4);
60 
61 		nstr = of_fdt_get_string(blob, noff);
62 		if (nstr == NULL) {
63 			pr_warning("Can't find property index name !\n");
64 			return NULL;
65 		}
66 		if (strcmp(name, nstr) == 0) {
67 			if (size)
68 				*size = sz;
69 			return (void *)p;
70 		}
71 		p += sz;
72 		p = ALIGN(p, 4);
73 	} while (1);
74 }
75 
76 /**
77  * of_fdt_is_compatible - Return true if given node from the given blob has
78  * compat in its compatible list
79  * @blob: A device tree blob
80  * @node: node to test
81  * @compat: compatible string to compare with compatible list.
82  *
83  * On match, returns a non-zero value with smaller values returned for more
84  * specific compatible values.
85  */
86 int of_fdt_is_compatible(struct boot_param_header *blob,
87 		      unsigned long node, const char *compat)
88 {
89 	const char *cp;
90 	unsigned long cplen, l, score = 0;
91 
92 	cp = of_fdt_get_property(blob, node, "compatible", &cplen);
93 	if (cp == NULL)
94 		return 0;
95 	while (cplen > 0) {
96 		score++;
97 		if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
98 			return score;
99 		l = strlen(cp) + 1;
100 		cp += l;
101 		cplen -= l;
102 	}
103 
104 	return 0;
105 }
106 
107 /**
108  * of_fdt_match - Return true if node matches a list of compatible values
109  */
110 int of_fdt_match(struct boot_param_header *blob, unsigned long node,
111                  const char *const *compat)
112 {
113 	unsigned int tmp, score = 0;
114 
115 	if (!compat)
116 		return 0;
117 
118 	while (*compat) {
119 		tmp = of_fdt_is_compatible(blob, node, *compat);
120 		if (tmp && (score == 0 || (tmp < score)))
121 			score = tmp;
122 		compat++;
123 	}
124 
125 	return score;
126 }
127 
128 static void *unflatten_dt_alloc(unsigned long *mem, unsigned long size,
129 				       unsigned long align)
130 {
131 	void *res;
132 
133 	*mem = ALIGN(*mem, align);
134 	res = (void *)*mem;
135 	*mem += size;
136 
137 	return res;
138 }
139 
140 /**
141  * unflatten_dt_node - Alloc and populate a device_node from the flat tree
142  * @blob: The parent device tree blob
143  * @mem: Memory chunk to use for allocating device nodes and properties
144  * @p: pointer to node in flat tree
145  * @dad: Parent struct device_node
146  * @allnextpp: pointer to ->allnext from last allocated device_node
147  * @fpsize: Size of the node path up at the current depth.
148  */
149 static unsigned long unflatten_dt_node(struct boot_param_header *blob,
150 				unsigned long mem,
151 				unsigned long *p,
152 				struct device_node *dad,
153 				struct device_node ***allnextpp,
154 				unsigned long fpsize)
155 {
156 	struct device_node *np;
157 	struct property *pp, **prev_pp = NULL;
158 	char *pathp;
159 	u32 tag;
160 	unsigned int l, allocl;
161 	int has_name = 0;
162 	int new_format = 0;
163 
164 	tag = be32_to_cpup((__be32 *)(*p));
165 	if (tag != OF_DT_BEGIN_NODE) {
166 		pr_err("Weird tag at start of node: %x\n", tag);
167 		return mem;
168 	}
169 	*p += 4;
170 	pathp = (char *)*p;
171 	l = allocl = strlen(pathp) + 1;
172 	*p = ALIGN(*p + l, 4);
173 
174 	/* version 0x10 has a more compact unit name here instead of the full
175 	 * path. we accumulate the full path size using "fpsize", we'll rebuild
176 	 * it later. We detect this because the first character of the name is
177 	 * not '/'.
178 	 */
179 	if ((*pathp) != '/') {
180 		new_format = 1;
181 		if (fpsize == 0) {
182 			/* root node: special case. fpsize accounts for path
183 			 * plus terminating zero. root node only has '/', so
184 			 * fpsize should be 2, but we want to avoid the first
185 			 * level nodes to have two '/' so we use fpsize 1 here
186 			 */
187 			fpsize = 1;
188 			allocl = 2;
189 			l = 1;
190 			*pathp = '\0';
191 		} else {
192 			/* account for '/' and path size minus terminal 0
193 			 * already in 'l'
194 			 */
195 			fpsize += l;
196 			allocl = fpsize;
197 		}
198 	}
199 
200 	np = unflatten_dt_alloc(&mem, sizeof(struct device_node) + allocl,
201 				__alignof__(struct device_node));
202 	if (allnextpp) {
203 		char *fn;
204 		memset(np, 0, sizeof(*np));
205 		np->full_name = fn = ((char *)np) + sizeof(*np);
206 		if (new_format) {
207 			/* rebuild full path for new format */
208 			if (dad && dad->parent) {
209 				strcpy(fn, dad->full_name);
210 #ifdef DEBUG
211 				if ((strlen(fn) + l + 1) != allocl) {
212 					pr_debug("%s: p: %d, l: %d, a: %d\n",
213 						pathp, (int)strlen(fn),
214 						l, allocl);
215 				}
216 #endif
217 				fn += strlen(fn);
218 			}
219 			*(fn++) = '/';
220 		}
221 		memcpy(fn, pathp, l);
222 
223 		prev_pp = &np->properties;
224 		**allnextpp = np;
225 		*allnextpp = &np->allnext;
226 		if (dad != NULL) {
227 			np->parent = dad;
228 			/* we temporarily use the next field as `last_child'*/
229 			if (dad->next == NULL)
230 				dad->child = np;
231 			else
232 				dad->next->sibling = np;
233 			dad->next = np;
234 		}
235 		kref_init(&np->kref);
236 	}
237 	/* process properties */
238 	while (1) {
239 		u32 sz, noff;
240 		char *pname;
241 
242 		tag = be32_to_cpup((__be32 *)(*p));
243 		if (tag == OF_DT_NOP) {
244 			*p += 4;
245 			continue;
246 		}
247 		if (tag != OF_DT_PROP)
248 			break;
249 		*p += 4;
250 		sz = be32_to_cpup((__be32 *)(*p));
251 		noff = be32_to_cpup((__be32 *)((*p) + 4));
252 		*p += 8;
253 		if (be32_to_cpu(blob->version) < 0x10)
254 			*p = ALIGN(*p, sz >= 8 ? 8 : 4);
255 
256 		pname = of_fdt_get_string(blob, noff);
257 		if (pname == NULL) {
258 			pr_info("Can't find property name in list !\n");
259 			break;
260 		}
261 		if (strcmp(pname, "name") == 0)
262 			has_name = 1;
263 		l = strlen(pname) + 1;
264 		pp = unflatten_dt_alloc(&mem, sizeof(struct property),
265 					__alignof__(struct property));
266 		if (allnextpp) {
267 			/* We accept flattened tree phandles either in
268 			 * ePAPR-style "phandle" properties, or the
269 			 * legacy "linux,phandle" properties.  If both
270 			 * appear and have different values, things
271 			 * will get weird.  Don't do that. */
272 			if ((strcmp(pname, "phandle") == 0) ||
273 			    (strcmp(pname, "linux,phandle") == 0)) {
274 				if (np->phandle == 0)
275 					np->phandle = be32_to_cpup((__be32*)*p);
276 			}
277 			/* And we process the "ibm,phandle" property
278 			 * used in pSeries dynamic device tree
279 			 * stuff */
280 			if (strcmp(pname, "ibm,phandle") == 0)
281 				np->phandle = be32_to_cpup((__be32 *)*p);
282 			pp->name = pname;
283 			pp->length = sz;
284 			pp->value = (void *)*p;
285 			*prev_pp = pp;
286 			prev_pp = &pp->next;
287 		}
288 		*p = ALIGN((*p) + sz, 4);
289 	}
290 	/* with version 0x10 we may not have the name property, recreate
291 	 * it here from the unit name if absent
292 	 */
293 	if (!has_name) {
294 		char *p1 = pathp, *ps = pathp, *pa = NULL;
295 		int sz;
296 
297 		while (*p1) {
298 			if ((*p1) == '@')
299 				pa = p1;
300 			if ((*p1) == '/')
301 				ps = p1 + 1;
302 			p1++;
303 		}
304 		if (pa < ps)
305 			pa = p1;
306 		sz = (pa - ps) + 1;
307 		pp = unflatten_dt_alloc(&mem, sizeof(struct property) + sz,
308 					__alignof__(struct property));
309 		if (allnextpp) {
310 			pp->name = "name";
311 			pp->length = sz;
312 			pp->value = pp + 1;
313 			*prev_pp = pp;
314 			prev_pp = &pp->next;
315 			memcpy(pp->value, ps, sz - 1);
316 			((char *)pp->value)[sz - 1] = 0;
317 			pr_debug("fixed up name for %s -> %s\n", pathp,
318 				(char *)pp->value);
319 		}
320 	}
321 	if (allnextpp) {
322 		*prev_pp = NULL;
323 		np->name = of_get_property(np, "name", NULL);
324 		np->type = of_get_property(np, "device_type", NULL);
325 
326 		if (!np->name)
327 			np->name = "<NULL>";
328 		if (!np->type)
329 			np->type = "<NULL>";
330 	}
331 	while (tag == OF_DT_BEGIN_NODE || tag == OF_DT_NOP) {
332 		if (tag == OF_DT_NOP)
333 			*p += 4;
334 		else
335 			mem = unflatten_dt_node(blob, mem, p, np, allnextpp,
336 						fpsize);
337 		tag = be32_to_cpup((__be32 *)(*p));
338 	}
339 	if (tag != OF_DT_END_NODE) {
340 		pr_err("Weird tag at end of node: %x\n", tag);
341 		return mem;
342 	}
343 	*p += 4;
344 	return mem;
345 }
346 
347 /**
348  * __unflatten_device_tree - create tree of device_nodes from flat blob
349  *
350  * unflattens a device-tree, creating the
351  * tree of struct device_node. It also fills the "name" and "type"
352  * pointers of the nodes so the normal device-tree walking functions
353  * can be used.
354  * @blob: The blob to expand
355  * @mynodes: The device_node tree created by the call
356  * @dt_alloc: An allocator that provides a virtual address to memory
357  * for the resulting tree
358  */
359 static void __unflatten_device_tree(struct boot_param_header *blob,
360 			     struct device_node **mynodes,
361 			     void * (*dt_alloc)(u64 size, u64 align))
362 {
363 	unsigned long start, mem, size;
364 	struct device_node **allnextp = mynodes;
365 
366 	pr_debug(" -> unflatten_device_tree()\n");
367 
368 	if (!blob) {
369 		pr_debug("No device tree pointer\n");
370 		return;
371 	}
372 
373 	pr_debug("Unflattening device tree:\n");
374 	pr_debug("magic: %08x\n", be32_to_cpu(blob->magic));
375 	pr_debug("size: %08x\n", be32_to_cpu(blob->totalsize));
376 	pr_debug("version: %08x\n", be32_to_cpu(blob->version));
377 
378 	if (be32_to_cpu(blob->magic) != OF_DT_HEADER) {
379 		pr_err("Invalid device tree blob header\n");
380 		return;
381 	}
382 
383 	/* First pass, scan for size */
384 	start = ((unsigned long)blob) +
385 		be32_to_cpu(blob->off_dt_struct);
386 	size = unflatten_dt_node(blob, 0, &start, NULL, NULL, 0);
387 	size = (size | 3) + 1;
388 
389 	pr_debug("  size is %lx, allocating...\n", size);
390 
391 	/* Allocate memory for the expanded device tree */
392 	mem = (unsigned long)
393 		dt_alloc(size + 4, __alignof__(struct device_node));
394 
395 	((__be32 *)mem)[size / 4] = cpu_to_be32(0xdeadbeef);
396 
397 	pr_debug("  unflattening %lx...\n", mem);
398 
399 	/* Second pass, do actual unflattening */
400 	start = ((unsigned long)blob) +
401 		be32_to_cpu(blob->off_dt_struct);
402 	unflatten_dt_node(blob, mem, &start, NULL, &allnextp, 0);
403 	if (be32_to_cpup((__be32 *)start) != OF_DT_END)
404 		pr_warning("Weird tag at end of tree: %08x\n", *((u32 *)start));
405 	if (be32_to_cpu(((__be32 *)mem)[size / 4]) != 0xdeadbeef)
406 		pr_warning("End of tree marker overwritten: %08x\n",
407 			   be32_to_cpu(((__be32 *)mem)[size / 4]));
408 	*allnextp = NULL;
409 
410 	pr_debug(" <- unflatten_device_tree()\n");
411 }
412 
413 static void *kernel_tree_alloc(u64 size, u64 align)
414 {
415 	return kzalloc(size, GFP_KERNEL);
416 }
417 
418 /**
419  * of_fdt_unflatten_tree - create tree of device_nodes from flat blob
420  *
421  * unflattens the device-tree passed by the firmware, creating the
422  * tree of struct device_node. It also fills the "name" and "type"
423  * pointers of the nodes so the normal device-tree walking functions
424  * can be used.
425  */
426 void of_fdt_unflatten_tree(unsigned long *blob,
427 			struct device_node **mynodes)
428 {
429 	struct boot_param_header *device_tree =
430 		(struct boot_param_header *)blob;
431 	__unflatten_device_tree(device_tree, mynodes, &kernel_tree_alloc);
432 }
433 EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree);
434 
435 /* Everything below here references initial_boot_params directly. */
436 int __initdata dt_root_addr_cells;
437 int __initdata dt_root_size_cells;
438 
439 struct boot_param_header *initial_boot_params;
440 
441 #ifdef CONFIG_OF_EARLY_FLATTREE
442 
443 /**
444  * of_scan_flat_dt - scan flattened tree blob and call callback on each.
445  * @it: callback function
446  * @data: context data pointer
447  *
448  * This function is used to scan the flattened device-tree, it is
449  * used to extract the memory information at boot before we can
450  * unflatten the tree
451  */
452 int __init of_scan_flat_dt(int (*it)(unsigned long node,
453 				     const char *uname, int depth,
454 				     void *data),
455 			   void *data)
456 {
457 	unsigned long p = ((unsigned long)initial_boot_params) +
458 		be32_to_cpu(initial_boot_params->off_dt_struct);
459 	int rc = 0;
460 	int depth = -1;
461 
462 	do {
463 		u32 tag = be32_to_cpup((__be32 *)p);
464 		const char *pathp;
465 
466 		p += 4;
467 		if (tag == OF_DT_END_NODE) {
468 			depth--;
469 			continue;
470 		}
471 		if (tag == OF_DT_NOP)
472 			continue;
473 		if (tag == OF_DT_END)
474 			break;
475 		if (tag == OF_DT_PROP) {
476 			u32 sz = be32_to_cpup((__be32 *)p);
477 			p += 8;
478 			if (be32_to_cpu(initial_boot_params->version) < 0x10)
479 				p = ALIGN(p, sz >= 8 ? 8 : 4);
480 			p += sz;
481 			p = ALIGN(p, 4);
482 			continue;
483 		}
484 		if (tag != OF_DT_BEGIN_NODE) {
485 			pr_err("Invalid tag %x in flat device tree!\n", tag);
486 			return -EINVAL;
487 		}
488 		depth++;
489 		pathp = (char *)p;
490 		p = ALIGN(p + strlen(pathp) + 1, 4);
491 		if (*pathp == '/')
492 			pathp = kbasename(pathp);
493 		rc = it(p, pathp, depth, data);
494 		if (rc != 0)
495 			break;
496 	} while (1);
497 
498 	return rc;
499 }
500 
501 /**
502  * of_get_flat_dt_root - find the root node in the flat blob
503  */
504 unsigned long __init of_get_flat_dt_root(void)
505 {
506 	unsigned long p = ((unsigned long)initial_boot_params) +
507 		be32_to_cpu(initial_boot_params->off_dt_struct);
508 
509 	while (be32_to_cpup((__be32 *)p) == OF_DT_NOP)
510 		p += 4;
511 	BUG_ON(be32_to_cpup((__be32 *)p) != OF_DT_BEGIN_NODE);
512 	p += 4;
513 	return ALIGN(p + strlen((char *)p) + 1, 4);
514 }
515 
516 /**
517  * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
518  *
519  * This function can be used within scan_flattened_dt callback to get
520  * access to properties
521  */
522 void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
523 				 unsigned long *size)
524 {
525 	return of_fdt_get_property(initial_boot_params, node, name, size);
526 }
527 
528 /**
529  * of_flat_dt_is_compatible - Return true if given node has compat in compatible list
530  * @node: node to test
531  * @compat: compatible string to compare with compatible list.
532  */
533 int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
534 {
535 	return of_fdt_is_compatible(initial_boot_params, node, compat);
536 }
537 
538 /**
539  * of_flat_dt_match - Return true if node matches a list of compatible values
540  */
541 int __init of_flat_dt_match(unsigned long node, const char *const *compat)
542 {
543 	return of_fdt_match(initial_boot_params, node, compat);
544 }
545 
546 #ifdef CONFIG_BLK_DEV_INITRD
547 /**
548  * early_init_dt_check_for_initrd - Decode initrd location from flat tree
549  * @node: reference to node containing initrd location ('chosen')
550  */
551 void __init early_init_dt_check_for_initrd(unsigned long node)
552 {
553 	unsigned long start, end, len;
554 	__be32 *prop;
555 
556 	pr_debug("Looking for initrd properties... ");
557 
558 	prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);
559 	if (!prop)
560 		return;
561 	start = of_read_ulong(prop, len/4);
562 
563 	prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
564 	if (!prop)
565 		return;
566 	end = of_read_ulong(prop, len/4);
567 
568 	early_init_dt_setup_initrd_arch(start, end);
569 	pr_debug("initrd_start=0x%lx  initrd_end=0x%lx\n", start, end);
570 }
571 #else
572 inline void early_init_dt_check_for_initrd(unsigned long node)
573 {
574 }
575 #endif /* CONFIG_BLK_DEV_INITRD */
576 
577 /**
578  * early_init_dt_scan_root - fetch the top level address and size cells
579  */
580 int __init early_init_dt_scan_root(unsigned long node, const char *uname,
581 				   int depth, void *data)
582 {
583 	__be32 *prop;
584 
585 	if (depth != 0)
586 		return 0;
587 
588 	dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
589 	dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
590 
591 	prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
592 	if (prop)
593 		dt_root_size_cells = be32_to_cpup(prop);
594 	pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells);
595 
596 	prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
597 	if (prop)
598 		dt_root_addr_cells = be32_to_cpup(prop);
599 	pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells);
600 
601 	/* break now */
602 	return 1;
603 }
604 
605 u64 __init dt_mem_next_cell(int s, __be32 **cellp)
606 {
607 	__be32 *p = *cellp;
608 
609 	*cellp = p + s;
610 	return of_read_number(p, s);
611 }
612 
613 /**
614  * early_init_dt_scan_memory - Look for an parse memory nodes
615  */
616 int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
617 				     int depth, void *data)
618 {
619 	char *type = of_get_flat_dt_prop(node, "device_type", NULL);
620 	__be32 *reg, *endp;
621 	unsigned long l;
622 
623 	/* We are scanning "memory" nodes only */
624 	if (type == NULL) {
625 		/*
626 		 * The longtrail doesn't have a device_type on the
627 		 * /memory node, so look for the node called /memory@0.
628 		 */
629 		if (depth != 1 || strcmp(uname, "memory@0") != 0)
630 			return 0;
631 	} else if (strcmp(type, "memory") != 0)
632 		return 0;
633 
634 	reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
635 	if (reg == NULL)
636 		reg = of_get_flat_dt_prop(node, "reg", &l);
637 	if (reg == NULL)
638 		return 0;
639 
640 	endp = reg + (l / sizeof(__be32));
641 
642 	pr_debug("memory scan node %s, reg size %ld, data: %x %x %x %x,\n",
643 	    uname, l, reg[0], reg[1], reg[2], reg[3]);
644 
645 	while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
646 		u64 base, size;
647 
648 		base = dt_mem_next_cell(dt_root_addr_cells, &reg);
649 		size = dt_mem_next_cell(dt_root_size_cells, &reg);
650 
651 		if (size == 0)
652 			continue;
653 		pr_debug(" - %llx ,  %llx\n", (unsigned long long)base,
654 		    (unsigned long long)size);
655 
656 		early_init_dt_add_memory_arch(base, size);
657 	}
658 
659 	return 0;
660 }
661 
662 int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
663 				     int depth, void *data)
664 {
665 	unsigned long l;
666 	char *p;
667 
668 	pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname);
669 
670 	if (depth != 1 || !data ||
671 	    (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
672 		return 0;
673 
674 	early_init_dt_check_for_initrd(node);
675 
676 	/* Retrieve command line */
677 	p = of_get_flat_dt_prop(node, "bootargs", &l);
678 	if (p != NULL && l > 0)
679 		strlcpy(data, p, min((int)l, COMMAND_LINE_SIZE));
680 
681 	/*
682 	 * CONFIG_CMDLINE is meant to be a default in case nothing else
683 	 * managed to set the command line, unless CONFIG_CMDLINE_FORCE
684 	 * is set in which case we override whatever was found earlier.
685 	 */
686 #ifdef CONFIG_CMDLINE
687 #ifndef CONFIG_CMDLINE_FORCE
688 	if (!((char *)data)[0])
689 #endif
690 		strlcpy(data, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
691 #endif /* CONFIG_CMDLINE */
692 
693 	pr_debug("Command line is: %s\n", (char*)data);
694 
695 	/* break now */
696 	return 1;
697 }
698 
699 /**
700  * unflatten_device_tree - create tree of device_nodes from flat blob
701  *
702  * unflattens the device-tree passed by the firmware, creating the
703  * tree of struct device_node. It also fills the "name" and "type"
704  * pointers of the nodes so the normal device-tree walking functions
705  * can be used.
706  */
707 void __init unflatten_device_tree(void)
708 {
709 	__unflatten_device_tree(initial_boot_params, &of_allnodes,
710 				early_init_dt_alloc_memory_arch);
711 
712 	/* Get pointer to "/chosen" and "/aliasas" nodes for use everywhere */
713 	of_alias_scan(early_init_dt_alloc_memory_arch);
714 }
715 
716 #endif /* CONFIG_OF_EARLY_FLATTREE */
717