aboutsummaryrefslogtreecommitdiff
path: root/drivers/of/fdt.c
blob: a4fa9ad31b8f7cfb62f45abf47ada0649d87b867 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
/*
 * Functions for working with the Flattened Device Tree data format
 *
 * Copyright 2009 Benjamin Herrenschmidt, IBM Corp
 * benh@kernel.crashing.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/initrd.h>
#include <linux/memblock.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/slab.h>

#include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
#ifdef CONFIG_PPC
#include <asm/machdep.h>
#endif /* CONFIG_PPC */

#include <asm/page.h>

char *of_fdt_get_string(struct boot_param_header *blob, u32 offset)
{
	return ((char *)blob) +
		be32_to_cpu(blob->off_dt_strings) + offset;
}

/**
 * of_fdt_get_property - Given a node in the given flat blob, return
 * the property ptr
 */
void *of_fdt_get_property(struct boot_param_header *blob,
		       unsigned long node, const char *name,
		       unsigned long *size)
{
	unsigned long p = node;

	do {
		u32 tag = be32_to_cpup((__be32 *)p);
		u32 sz, noff;
		const char *nstr;

		p += 4;
		if (tag == OF_DT_NOP)
			continue;
		if (tag != OF_DT_PROP)
			return NULL;

		sz = be32_to_cpup((__be32 *)p);
		noff = be32_to_cpup((__be32 *)(p + 4));
		p += 8;
		if (be32_to_cpu(blob->version) < 0x10)
			p = ALIGN(p, sz >= 8 ? 8 : 4);

		nstr = of_fdt_get_string(blob, noff);
		if (nstr == NULL) {
			pr_warning("Can't find property index name !\n");
			return NULL;
		}
		if (strcmp(name, nstr) == 0) {
			if (size)
				*size = sz;
			return (void *)p;
		}
		p += sz;
		p = ALIGN(p, 4);
	} while (1);
}

/**
 * of_fdt_is_compatible - Return true if given node from the given blob has
 * compat in its compatible list
 * @blob: A device tree blob
 * @node: node to test
 * @compat: compatible string to compare with compatible list.
 *
 * On match, returns a non-zero value with smaller values returned for more
 * specific compatible values.
 */
int of_fdt_is_compatible(struct boot_param_header *blob,
		      unsigned long node, const char *compat)
{
	const char *cp;
	unsigned long cplen, l, score = 0;

	cp = of_fdt_get_property(blob, node, "compatible", &cplen);
	if (cp == NULL)
		return 0;
	while (cplen > 0) {
		score++;
		if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
			return score;
		l = strlen(cp) + 1;
		cp += l;
		cplen -= l;
	}

	return 0;
}

/**
 * of_fdt_match - Return true if node matches a list of compatible values
 */
int of_fdt_match(struct boot_param_header *blob, unsigned long node,
                 const char *const *compat)
{
	unsigned int tmp, score = 0;

	if (!compat)
		return 0;

	while (*compat) {
		tmp = of_fdt_is_compatible(blob, node, *compat);
		if (tmp && (score == 0 || (tmp < score)))
			score = tmp;
		compat++;
	}

	return score;
}

static void *unflatten_dt_alloc(void **mem, unsigned long size,
				       unsigned long align)
{
	void *res;

	*mem = PTR_ALIGN(*mem, align);
	res = *mem;
	*mem += size;

	return res;
}

/**
 * unflatten_dt_node - Alloc and populate a device_node from the flat tree
 * @blob: The parent device tree blob
 * @mem: Memory chunk to use for allocating device nodes and properties
 * @p: pointer to node in flat tree
 * @dad: Parent struct device_node
 * @allnextpp: pointer to ->allnext from last allocated device_node
 * @fpsize: Size of the node path up at the current depth.
 */
static void * unflatten_dt_node(struct boot_param_header *blob,
				void *mem,
				void **p,
				struct device_node *dad,
				struct device_node ***allnextpp,
				unsigned long fpsize)
{
	struct device_node *np;
	struct property *pp, **prev_pp = NULL;
	char *pathp;
	u32 tag;
	unsigned int l, allocl;
	int has_name = 0;
	int new_format = 0;

	tag = be32_to_cpup(*p);
	if (tag != OF_DT_BEGIN_NODE) {
		pr_err("Weird tag at start of node: %x\n", tag);
		return mem;
	}
	*p += 4;
	pathp = *p;
	l = allocl = strlen(pathp) + 1;
	*p = PTR_ALIGN(*p + l, 4);

	/* version 0x10 has a more compact unit name here instead of the full
	 * path. we accumulate the full path size using "fpsize", we'll rebuild
	 * it later. We detect this because the first character of the name is
	 * not '/'.
	 */
	if ((*pathp) != '/') {
		new_format = 1;
		if (fpsize == 0) {
			/* root node: special case. fpsize accounts for path
			 * plus terminating zero. root node only has '/', so
			 * fpsize should be 2, but we want to avoid the first
			 * level nodes to have two '/' so we use fpsize 1 here
			 */
			fpsize = 1;
			allocl = 2;
			l = 1;
			*pathp = '\0';
		} else {
			/* account for '/' and path size minus terminal 0
			 * already in 'l'
			 */
			fpsize += l;
			allocl = fpsize;
		}
	}

	np = unflatten_dt_alloc(&mem, sizeof(struct device_node) + allocl,
				__alignof__(struct device_node));
	if (allnextpp) {
		char *fn;
		np->full_name = fn = ((char *)np) + sizeof(*np);
		if (new_format) {
			/* rebuild full path for new format */
			if (dad && dad->parent) {
				strcpy(fn, dad->full_name);
#ifdef DEBUG
				if ((strlen(fn) + l + 1) != allocl) {
					pr_debug("%s: p: %d, l: %d, a: %d\n",
						pathp, (int)strlen(fn),
						l, allocl);
				}
#endif
				fn += strlen(fn);
			}
			*(fn++) = '/';
		}
		memcpy(fn, pathp, l);

		prev_pp = &np->properties;
		**allnextpp = np;
		*allnextpp = &np->allnext;
		if (dad != NULL) {
			np->parent = dad;
			/* we temporarily use the next field as `last_child'*/
			if (dad->next == NULL)
				dad->child = np;
			else
				dad->next->sibling = np;
			dad->next = np;
		}
		kref_init(&np->kref);
	}
	/* process properties */
	while (1) {
		u32 sz, noff;
		char *pname;

		tag = be32_to_cpup(*p);
		if (tag == OF_DT_NOP) {
			*p += 4;
			continue;
		}
		if (tag != OF_DT_PROP)
			break;
		*p += 4;
		sz = be32_to_cpup(*p);
		noff = be32_to_cpup(*p + 4);
		*p += 8;
		if (be32_to_cpu(blob->version) < 0x10)
			*p = PTR_ALIGN(*p, sz >= 8 ? 8 : 4);

		pname = of_fdt_get_string(blob, noff);
		if (pname == NULL) {
			pr_info("Can't find property name in list !\n");
			break;
		}
		if (strcmp(pname, "name") == 0)
			has_name = 1;
		l = strlen(pname) + 1;
		pp = unflatten_dt_alloc(&mem, sizeof(struct property),
					__alignof__(struct property));
		if (allnextpp) {
			/* We accept flattened tree phandles either in
			 * ePAPR-style "phandle" properties, or the
			 * legacy "linux,phandle" properties.  If both
			 * appear and have different values, things
			 * will get weird.  Don't do that. */
			if ((strcmp(pname, "phandle") == 0) ||
			    (strcmp(pname, "linux,phandle") == 0)) {
				if (np->phandle == 0)
					np->phandle = be32_to_cpup((__be32*)*p);
			}
			/* And we process the "ibm,phandle" property
			 * used in pSeries dynamic device tree
			 * stuff */
			if (strcmp(pname, "ibm,phandle") == 0)
				np->phandle = be32_to_cpup((__be32 *)*p);
			pp->name = pname;
			pp->length = sz;
			pp->value = *p;
			*prev_pp = pp;
			prev_pp = &pp->next;
		}
		*p = PTR_ALIGN((*p) + sz, 4);
	}
	/* with version 0x10 we may not have the name property, recreate
	 * it here from the unit name if absent
	 */
	if (!has_name) {
		char *p1 = pathp, *ps = pathp, *pa = NULL;
		int sz;

		while (*p1) {
			if ((*p1) == '@')
				pa = p1;
			if ((*p1) == '/')
				ps = p1 + 1;
			p1++;
		}
		if (pa < ps)
			pa = p1;
		sz = (pa - ps) + 1;
		pp = unflatten_dt_alloc(&mem, sizeof(struct property) + sz,
					__alignof__(struct property));
		if (allnextpp) {
			pp->name = "name";
			pp->length = sz;
			pp->value = pp + 1;
			*prev_pp = pp;
			prev_pp = &pp->next;
			memcpy(pp->value, ps, sz - 1);
			((char *)pp->value)[sz - 1] = 0;
			pr_debug("fixed up name for %s -> %s\n", pathp,
				(char *)pp->value);
		}
	}
	if (allnextpp) {
		*prev_pp = NULL;
		np->name = of_get_property(np, "name", NULL);
		np->type = of_get_property(np, "device_type", NULL);

		if (!np->name)
			np->name = "<NULL>";
		if (!np->type)
			np->type = "<NULL>";
	}
	while (tag == OF_DT_BEGIN_NODE || tag == OF_DT_NOP) {
		if (tag == OF_DT_NOP)
			*p += 4;
		else
			mem = unflatten_dt_node(blob, mem, p, np, allnextpp,
						fpsize);
		tag = be32_to_cpup(*p);
	}
	if (tag != OF_DT_END_NODE) {
		pr_err("Weird tag at end of node: %x\n", tag);
		return mem;
	}
	*p += 4;
	return mem;
}

/**
 * __unflatten_device_tree - create tree of device_nodes from flat blob
 *
 * unflattens a device-tree, creating the
 * tree of struct device_node. It also fills the "name" and "type"
 * pointers of the nodes so the normal device-tree walking functions
 * can be used.
 * @blob: The blob to expand
 * @mynodes: The device_node tree created by the call
 * @dt_alloc: An allocator that provides a virtual address to memory
 * for the resulting tree
 */
static void __unflatten_device_tree(struct boot_param_header *blob,
			     struct device_node **mynodes,
			     void * (*dt_alloc)(u64 size, u64 align))
{
	unsigned long size;
	void *start, *mem;
	struct device_node **allnextp = mynodes;

	pr_debug(" -> unflatten_device_tree()\n");

	if (!blob) {
		pr_debug("No device tree pointer\n");
		return;
	}

	pr_debug("Unflattening device tree:\n");
	pr_debug("magic: %08x\n", be32_to_cpu(blob->magic));
	pr_debug("size: %08x\n", be32_to_cpu(blob->totalsize));
	pr_debug("version: %08x\n", be32_to_cpu(blob->version));

	if (be32_to_cpu(blob->magic) != OF_DT_HEADER) {
		pr_err("Invalid device tree blob header\n");
		return;
	}

	/* First pass, scan for size */
	start = ((void *)blob) + be32_to_cpu(blob->off_dt_struct);
	size = (unsigned long)unflatten_dt_node(blob, 0, &start, NULL, NULL, 0);
	size = ALIGN(size, 4);

	pr_debug("  size is %lx, allocating...\n", size);

	/* Allocate memory for the expanded device tree */
	mem = dt_alloc(size + 4, __alignof__(struct device_node));
	memset(mem, 0, size);

	*(__be32 *)(mem + size) = cpu_to_be32(0xdeadbeef);

	pr_debug("  unflattening %p...\n", mem);

	/* Second pass, do actual unflattening */
	start = ((void *)blob) + be32_to_cpu(blob->off_dt_struct);
	unflatten_dt_node(blob, mem, &start, NULL, &allnextp, 0);
	if (be32_to_cpup(start) != OF_DT_END)
		pr_warning("Weird tag at end of tree: %08x\n", be32_to_cpup(start));
	if (be32_to_cpup(mem + size) != 0xdeadbeef)
		pr_warning("End of tree marker overwritten: %08x\n",
			   be32_to_cpup(mem + size));
	*allnextp = NULL;

	pr_debug(" <- unflatten_device_tree()\n");
}

static void *kernel_tree_alloc(u64 size, u64 align)
{
	return kzalloc(size, GFP_KERNEL);
}

/**
 * of_fdt_unflatten_tree - create tree of device_nodes from flat blob
 *
 * unflattens the device-tree passed by the firmware, creating the
 * tree of struct device_node. It also fills the "name" and "type"
 * pointers of the nodes so the normal device-tree walking functions
 * can be used.
 */
void of_fdt_unflatten_tree(unsigned long *blob,
			struct device_node **mynodes)
{
	struct boot_param_header *device_tree =
		(struct boot_param_header *)blob;
	__unflatten_device_tree(device_tree, mynodes, &kernel_tree_alloc);
}
EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree);

/* Everything below here references initial_boot_params directly. */
int __initdata dt_root_addr_cells;
int __initdata dt_root_size_cells;

struct boot_param_header *initial_boot_params;

#ifdef CONFIG_OF_EARLY_FLATTREE

/**
 * of_scan_flat_dt - scan flattened tree blob and call callback on each.
 * @it: callback function
 * @data: context data pointer
 *
 * This function is used to scan the flattened device-tree, it is
 * used to extract the memory information at boot before we can
 * unflatten the tree
 */
int __init of_scan_flat_dt(int (*it)(unsigned long node,
				     const char *uname, int depth,
				     void *data),
			   void *data)
{
	unsigned long p = ((unsigned long)initial_boot_params) +
		be32_to_cpu(initial_boot_params->off_dt_struct);
	int rc = 0;
	int depth = -1;

	do {
		u32 tag = be32_to_cpup((__be32 *)p);
		const char *pathp;

		p += 4;
		if (tag == OF_DT_END_NODE) {
			depth--;
			continue;
		}
		if (tag == OF_DT_NOP)
			continue;
		if (tag == OF_DT_END)
			break;
		if (tag == OF_DT_PROP) {
			u32 sz = be32_to_cpup((__be32 *)p);
			p += 8;
			if (be32_to_cpu(initial_boot_params->version) < 0x10)
				p = ALIGN(p, sz >= 8 ? 8 : 4);
			p += sz;
			p = ALIGN(p, 4);
			continue;
		}
		if (tag != OF_DT_BEGIN_NODE) {
			pr_err("Invalid tag %x in flat device tree!\n", tag);
			return -EINVAL;
		}
		depth++;
		pathp = (char *)p;
		p = ALIGN(p + strlen(pathp) + 1, 4);
		if (*pathp == '/')
			pathp = kbasename(pathp);
		rc = it(p, pathp, depth, data);
		if (rc != 0)
			break;
	} while (1);

	return rc;
}

/**
 * of_get_flat_dt_root - find the root node in the flat blob
 */
unsigned long __init of_get_flat_dt_root(void)
{
	unsigned long p = ((unsigned long)initial_boot_params) +
		be32_to_cpu(initial_boot_params->off_dt_struct);

	while (be32_to_cpup((__be32 *)p) == OF_DT_NOP)
		p += 4;
	BUG_ON(be32_to_cpup((__be32 *)p) != OF_DT_BEGIN_NODE);
	p += 4;
	return ALIGN(p + strlen((char *)p) + 1, 4);
}

/**
 * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
 *
 * This function can be used within scan_flattened_dt callback to get
 * access to properties
 */
void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
				 unsigned long *size)
{
	return of_fdt_get_property(initial_boot_params, node, name, size);
}

/**
 * of_flat_dt_is_compatible - Return true if given node has compat in compatible list
 * @node: node to test
 * @compat: compatible string to compare with compatible list.
 */
int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
{
	return of_fdt_is_compatible(initial_boot_params, node, compat);
}

/**
 * of_flat_dt_match - Return true if node matches a list of compatible values
 */
int __init of_flat_dt_match(unsigned long node, const char *const *compat)
{
	return of_fdt_match(initial_boot_params, node, compat);
}

struct fdt_scan_status {
	const char *name;
	int namelen;
	int depth;
	int found;
	int (*iterator)(unsigned long node, const char *uname, int depth, void *data);
	void *data;
};

/**
 * fdt_scan_node_by_path - iterator for of_scan_flat_dt_by_path function
 */
static int __init fdt_scan_node_by_path(unsigned long node, const char *uname,
					int depth, void *data)
{
	struct fdt_scan_status *st = data;

	/*
	 * if scan at the requested fdt node has been completed,
	 * return -ENXIO to abort further scanning
	 */
	if (depth <= st->depth)
		return -ENXIO;

	/* requested fdt node has been found, so call iterator function */
	if (st->found)
		return st->iterator(node, uname, depth, st->data);

	/* check if scanning automata is entering next level of fdt nodes */
	if (depth == st->depth + 1 &&
	    strncmp(st->name, uname, st->namelen) == 0 &&
	    uname[st->namelen] == 0) {
		st->depth += 1;
		if (st->name[st->namelen] == 0) {
			st->found = 1;
		} else {
			const char *next = st->name + st->namelen + 1;
			st->name = next;
			st->namelen = strcspn(next, "/");
		}
		return 0;
	}

	/* scan next fdt node */
	return 0;
}

/**
 * of_scan_flat_dt_by_path - scan flattened tree blob and call callback on each
 *			     child of the given path.
 * @path: path to start searching for children
 * @it: callback function
 * @data: context data pointer
 *
 * This function is used to scan the flattened device-tree starting from the
 * node given by path. It is used to extract information (like reserved
 * memory), which is required on ealy boot before we can unflatten the tree.
 */
int __init of_scan_flat_dt_by_path(const char *path,
	int (*it)(unsigned long node, const char *name, int depth, void *data),
	void *data)
{
	struct fdt_scan_status st = {path, 0, -1, 0, it, data};
	int ret = 0;

	if (initial_boot_params)
                ret = of_scan_flat_dt(fdt_scan_node_by_path, &st);

	if (!st.found)
		return -ENOENT;
	else if (ret == -ENXIO)	/* scan has been completed */
		return 0;
	else
		return ret;
}

#ifdef CONFIG_BLK_DEV_INITRD
/**
 * early_init_dt_check_for_initrd - Decode initrd location from flat tree
 * @node: reference to node containing initrd location ('chosen')
 */
void __init early_init_dt_check_for_initrd(unsigned long node)
{
	u64 start, end;
	unsigned long len;
	__be32 *prop;

	pr_debug("Looking for initrd properties... ");

	prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);
	if (!prop)
		return;
	start = of_read_number(prop, len/4);

	prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
	if (!prop)
		return;
	end = of_read_number(prop, len/4);

	early_init_dt_setup_initrd_arch(start, end);
	pr_debug("initrd_start=0x%llx  initrd_end=0x%llx\n",
		 (unsigned long long)start, (unsigned long long)end);
}
#else
inline void early_init_dt_check_for_initrd(unsigned long node)
{
}
#endif /* CONFIG_BLK_DEV_INITRD */

/**
 * early_init_dt_scan_root - fetch the top level address and size cells
 */
int __init early_init_dt_scan_root(unsigned long node, const char *uname,
				   int depth, void *data)
{
	__be32 *prop;

	if (depth != 0)
		return 0;

	dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
	dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;

	prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
	if (prop)
		dt_root_size_cells = be32_to_cpup(prop);
	pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells);

	prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
	if (prop)
		dt_root_addr_cells = be32_to_cpup(prop);
	pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells);

	/* break now */
	return 1;
}

u64 __init dt_mem_next_cell(int s, __be32 **cellp)
{
	__be32 *p = *cellp;

	*cellp = p + s;
	return of_read_number(p, s);
}

/**
 * early_init_dt_scan_memory - Look for an parse memory nodes
 */
int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
				     int depth, void *data)
{
	char *type = of_get_flat_dt_prop(node, "device_type", NULL);
	__be32 *reg, *endp;
	unsigned long l;

	/* We are scanning "memory" nodes only */
	if (type == NULL) {
		/*
		 * The longtrail doesn't have a device_type on the
		 * /memory node, so look for the node called /memory@0.
		 */
		if (depth != 1 || strcmp(uname, "memory@0") != 0)
			return 0;
	} else if (strcmp(type, "memory") != 0)
		return 0;

	reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
	if (reg == NULL)
		reg = of_get_flat_dt_prop(node, "reg", &l);
	if (reg == NULL)
		return 0;

	endp = reg + (l / sizeof(__be32));

	pr_debug("memory scan node %s, reg size %ld, data: %x %x %x %x,\n",
	    uname, l, reg[0], reg[1], reg[2], reg[3]);

	while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
		u64 base, size;

		base = dt_mem_next_cell(dt_root_addr_cells, &reg);
		size = dt_mem_next_cell(dt_root_size_cells, &reg);

		if (size == 0)
			continue;
		pr_debug(" - %llx ,  %llx\n", (unsigned long long)base,
		    (unsigned long long)size);

		early_init_dt_add_memory_arch(base, size);
	}

	return 0;
}

int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
				     int depth, void *data)
{
	unsigned long l;
	char *p;

	pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname);

	if (depth != 1 || !data ||
	    (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
		return 0;

	early_init_dt_check_for_initrd(node);

	/* Retrieve command line */
	p = of_get_flat_dt_prop(node, "bootargs", &l);
	if (p != NULL && l > 0)
		strlcpy(data, p, min((int)l, COMMAND_LINE_SIZE));

	/*
	 * CONFIG_CMDLINE is meant to be a default in case nothing else
	 * managed to set the command line, unless CONFIG_CMDLINE_FORCE
	 * is set in which case we override whatever was found earlier.
	 */
#ifdef CONFIG_CMDLINE
#ifndef CONFIG_CMDLINE_FORCE
	if (!((char *)data)[0])
#endif
		strlcpy(data, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
#endif /* CONFIG_CMDLINE */

	pr_debug("Command line is: %s\n", (char*)data);

	/* break now */
	return 1;
}

#ifdef CONFIG_HAVE_MEMBLOCK
/*
 * called from unflatten_device_tree() to bootstrap devicetree itself
 * Architectures can override this definition if memblock isn't used
 */
void * __init __weak early_init_dt_alloc_memory_arch(u64 size, u64 align)
{
	return __va(memblock_alloc(size, align));
}
#endif

/**
 * unflatten_device_tree - create tree of device_nodes from flat blob
 *
 * unflattens the device-tree passed by the firmware, creating the
 * tree of struct device_node. It also fills the "name" and "type"
 * pointers of the nodes so the normal device-tree walking functions
 * can be used.
 */
void __init unflatten_device_tree(void)
{
	__unflatten_device_tree(initial_boot_params, &of_allnodes,
				early_init_dt_alloc_memory_arch);

	/* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */
	of_alias_scan(early_init_dt_alloc_memory_arch);
}

#endif /* CONFIG_OF_EARLY_FLATTREE */