1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Functions for working with the Flattened Device Tree data format
4  *
5  * Copyright 2009 Benjamin Herrenschmidt, IBM Corp
6  * benh@kernel.crashing.org
7  */
8 
9 #define pr_fmt(fmt)	"OF: fdt: " fmt
10 
11 #include <linux/crash_dump.h>
12 #include <linux/crc32.h>
13 #include <linux/kernel.h>
14 #include <linux/initrd.h>
15 #include <linux/memblock.h>
16 #include <linux/mutex.h>
17 #include <linux/of.h>
18 #include <linux/of_fdt.h>
19 #include <linux/of_reserved_mem.h>
20 #include <linux/sizes.h>
21 #include <linux/string.h>
22 #include <linux/errno.h>
23 #include <linux/slab.h>
24 #include <linux/libfdt.h>
25 #include <linux/debugfs.h>
26 #include <linux/serial_core.h>
27 #include <linux/sysfs.h>
28 #include <linux/random.h>
29 #include <linux/kmemleak.h>
30 
31 #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
32 #include <asm/page.h>
33 
34 #include "of_private.h"
35 
36 /*
37  * of_fdt_limit_memory - limit the number of regions in the /memory node
38  * @limit: maximum entries
39  *
40  * Adjust the flattened device tree to have at most 'limit' number of
41  * memory entries in the /memory node. This function may be called
42  * any time after initial_boot_param is set.
43  */
of_fdt_limit_memory(int limit)44 void __init of_fdt_limit_memory(int limit)
45 {
46 	int memory;
47 	int len;
48 	const void *val;
49 	int nr_address_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
50 	int nr_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
51 	const __be32 *addr_prop;
52 	const __be32 *size_prop;
53 	int root_offset;
54 	int cell_size;
55 
56 	root_offset = fdt_path_offset(initial_boot_params, "/");
57 	if (root_offset < 0)
58 		return;
59 
60 	addr_prop = fdt_getprop(initial_boot_params, root_offset,
61 				"#address-cells", NULL);
62 	if (addr_prop)
63 		nr_address_cells = fdt32_to_cpu(*addr_prop);
64 
65 	size_prop = fdt_getprop(initial_boot_params, root_offset,
66 				"#size-cells", NULL);
67 	if (size_prop)
68 		nr_size_cells = fdt32_to_cpu(*size_prop);
69 
70 	cell_size = sizeof(uint32_t)*(nr_address_cells + nr_size_cells);
71 
72 	memory = fdt_path_offset(initial_boot_params, "/memory");
73 	if (memory > 0) {
74 		val = fdt_getprop(initial_boot_params, memory, "reg", &len);
75 		if (len > limit*cell_size) {
76 			len = limit*cell_size;
77 			pr_debug("Limiting number of entries to %d\n", limit);
78 			fdt_setprop(initial_boot_params, memory, "reg", val,
79 					len);
80 		}
81 	}
82 }
83 
of_fdt_device_is_available(const void * blob,unsigned long node)84 static bool of_fdt_device_is_available(const void *blob, unsigned long node)
85 {
86 	const char *status = fdt_getprop(blob, node, "status", NULL);
87 
88 	if (!status)
89 		return true;
90 
91 	if (!strcmp(status, "ok") || !strcmp(status, "okay"))
92 		return true;
93 
94 	return false;
95 }
96 
unflatten_dt_alloc(void ** mem,unsigned long size,unsigned long align)97 static void *unflatten_dt_alloc(void **mem, unsigned long size,
98 				       unsigned long align)
99 {
100 	void *res;
101 
102 	*mem = PTR_ALIGN(*mem, align);
103 	res = *mem;
104 	*mem += size;
105 
106 	return res;
107 }
108 
populate_properties(const void * blob,int offset,void ** mem,struct device_node * np,const char * nodename,bool dryrun)109 static void populate_properties(const void *blob,
110 				int offset,
111 				void **mem,
112 				struct device_node *np,
113 				const char *nodename,
114 				bool dryrun)
115 {
116 	struct property *pp, **pprev = NULL;
117 	int cur;
118 	bool has_name = false;
119 
120 	pprev = &np->properties;
121 	for (cur = fdt_first_property_offset(blob, offset);
122 	     cur >= 0;
123 	     cur = fdt_next_property_offset(blob, cur)) {
124 		const __be32 *val;
125 		const char *pname;
126 		u32 sz;
127 
128 		val = fdt_getprop_by_offset(blob, cur, &pname, &sz);
129 		if (!val) {
130 			pr_warn("Cannot locate property at 0x%x\n", cur);
131 			continue;
132 		}
133 
134 		if (!pname) {
135 			pr_warn("Cannot find property name at 0x%x\n", cur);
136 			continue;
137 		}
138 
139 		if (!strcmp(pname, "name"))
140 			has_name = true;
141 
142 		pp = unflatten_dt_alloc(mem, sizeof(struct property),
143 					__alignof__(struct property));
144 		if (dryrun)
145 			continue;
146 
147 		/* We accept flattened tree phandles either in
148 		 * ePAPR-style "phandle" properties, or the
149 		 * legacy "linux,phandle" properties.  If both
150 		 * appear and have different values, things
151 		 * will get weird. Don't do that.
152 		 */
153 		if (!strcmp(pname, "phandle") ||
154 		    !strcmp(pname, "linux,phandle")) {
155 			if (!np->phandle)
156 				np->phandle = be32_to_cpup(val);
157 		}
158 
159 		/* And we process the "ibm,phandle" property
160 		 * used in pSeries dynamic device tree
161 		 * stuff
162 		 */
163 		if (!strcmp(pname, "ibm,phandle"))
164 			np->phandle = be32_to_cpup(val);
165 
166 		pp->name   = (char *)pname;
167 		pp->length = sz;
168 		pp->value  = (__be32 *)val;
169 		*pprev     = pp;
170 		pprev      = &pp->next;
171 	}
172 
173 	/* With version 0x10 we may not have the name property,
174 	 * recreate it here from the unit name if absent
175 	 */
176 	if (!has_name) {
177 		const char *p = nodename, *ps = p, *pa = NULL;
178 		int len;
179 
180 		while (*p) {
181 			if ((*p) == '@')
182 				pa = p;
183 			else if ((*p) == '/')
184 				ps = p + 1;
185 			p++;
186 		}
187 
188 		if (pa < ps)
189 			pa = p;
190 		len = (pa - ps) + 1;
191 		pp = unflatten_dt_alloc(mem, sizeof(struct property) + len,
192 					__alignof__(struct property));
193 		if (!dryrun) {
194 			pp->name   = "name";
195 			pp->length = len;
196 			pp->value  = pp + 1;
197 			*pprev     = pp;
198 			memcpy(pp->value, ps, len - 1);
199 			((char *)pp->value)[len - 1] = 0;
200 			pr_debug("fixed up name for %s -> %s\n",
201 				 nodename, (char *)pp->value);
202 		}
203 	}
204 }
205 
populate_node(const void * blob,int offset,void ** mem,struct device_node * dad,struct device_node ** pnp,bool dryrun)206 static int populate_node(const void *blob,
207 			  int offset,
208 			  void **mem,
209 			  struct device_node *dad,
210 			  struct device_node **pnp,
211 			  bool dryrun)
212 {
213 	struct device_node *np;
214 	const char *pathp;
215 	int len;
216 
217 	pathp = fdt_get_name(blob, offset, &len);
218 	if (!pathp) {
219 		*pnp = NULL;
220 		return len;
221 	}
222 
223 	len++;
224 
225 	np = unflatten_dt_alloc(mem, sizeof(struct device_node) + len,
226 				__alignof__(struct device_node));
227 	if (!dryrun) {
228 		char *fn;
229 		of_node_init(np);
230 		np->full_name = fn = ((char *)np) + sizeof(*np);
231 
232 		memcpy(fn, pathp, len);
233 
234 		if (dad != NULL) {
235 			np->parent = dad;
236 			np->sibling = dad->child;
237 			dad->child = np;
238 		}
239 	}
240 
241 	populate_properties(blob, offset, mem, np, pathp, dryrun);
242 	if (!dryrun) {
243 		np->name = of_get_property(np, "name", NULL);
244 		if (!np->name)
245 			np->name = "<NULL>";
246 	}
247 
248 	*pnp = np;
249 	return 0;
250 }
251 
reverse_nodes(struct device_node * parent)252 static void reverse_nodes(struct device_node *parent)
253 {
254 	struct device_node *child, *next;
255 
256 	/* In-depth first */
257 	child = parent->child;
258 	while (child) {
259 		reverse_nodes(child);
260 
261 		child = child->sibling;
262 	}
263 
264 	/* Reverse the nodes in the child list */
265 	child = parent->child;
266 	parent->child = NULL;
267 	while (child) {
268 		next = child->sibling;
269 
270 		child->sibling = parent->child;
271 		parent->child = child;
272 		child = next;
273 	}
274 }
275 
276 /**
277  * unflatten_dt_nodes - Alloc and populate a device_node from the flat tree
278  * @blob: The parent device tree blob
279  * @mem: Memory chunk to use for allocating device nodes and properties
280  * @dad: Parent struct device_node
281  * @nodepp: The device_node tree created by the call
282  *
283  * Return: The size of unflattened device tree or error code
284  */
unflatten_dt_nodes(const void * blob,void * mem,struct device_node * dad,struct device_node ** nodepp)285 static int unflatten_dt_nodes(const void *blob,
286 			      void *mem,
287 			      struct device_node *dad,
288 			      struct device_node **nodepp)
289 {
290 	struct device_node *root;
291 	int offset = 0, depth = 0, initial_depth = 0;
292 #define FDT_MAX_DEPTH	64
293 	struct device_node *nps[FDT_MAX_DEPTH];
294 	void *base = mem;
295 	bool dryrun = !base;
296 	int ret;
297 
298 	if (nodepp)
299 		*nodepp = NULL;
300 
301 	/*
302 	 * We're unflattening device sub-tree if @dad is valid. There are
303 	 * possibly multiple nodes in the first level of depth. We need
304 	 * set @depth to 1 to make fdt_next_node() happy as it bails
305 	 * immediately when negative @depth is found. Otherwise, the device
306 	 * nodes except the first one won't be unflattened successfully.
307 	 */
308 	if (dad)
309 		depth = initial_depth = 1;
310 
311 	root = dad;
312 	nps[depth] = dad;
313 
314 	for (offset = 0;
315 	     offset >= 0 && depth >= initial_depth;
316 	     offset = fdt_next_node(blob, offset, &depth)) {
317 		if (WARN_ON_ONCE(depth >= FDT_MAX_DEPTH))
318 			continue;
319 
320 		if (!IS_ENABLED(CONFIG_OF_KOBJ) &&
321 		    !of_fdt_device_is_available(blob, offset))
322 			continue;
323 
324 		ret = populate_node(blob, offset, &mem, nps[depth],
325 				   &nps[depth+1], dryrun);
326 		if (ret < 0)
327 			return ret;
328 
329 		if (!dryrun && nodepp && !*nodepp)
330 			*nodepp = nps[depth+1];
331 		if (!dryrun && !root)
332 			root = nps[depth+1];
333 	}
334 
335 	if (offset < 0 && offset != -FDT_ERR_NOTFOUND) {
336 		pr_err("Error %d processing FDT\n", offset);
337 		return -EINVAL;
338 	}
339 
340 	/*
341 	 * Reverse the child list. Some drivers assumes node order matches .dts
342 	 * node order
343 	 */
344 	if (!dryrun)
345 		reverse_nodes(root);
346 
347 	return mem - base;
348 }
349 
350 /**
351  * __unflatten_device_tree - create tree of device_nodes from flat blob
352  * @blob: The blob to expand
353  * @dad: Parent device node
354  * @mynodes: The device_node tree created by the call
355  * @dt_alloc: An allocator that provides a virtual address to memory
356  * for the resulting tree
357  * @detached: if true set OF_DETACHED on @mynodes
358  *
359  * unflattens a device-tree, creating the tree of struct device_node. It also
360  * fills the "name" and "type" pointers of the nodes so the normal device-tree
361  * walking functions can be used.
362  *
363  * Return: NULL on failure or the memory chunk containing the unflattened
364  * device tree on success.
365  */
__unflatten_device_tree(const void * blob,struct device_node * dad,struct device_node ** mynodes,void * (* dt_alloc)(u64 size,u64 align),bool detached)366 void *__unflatten_device_tree(const void *blob,
367 			      struct device_node *dad,
368 			      struct device_node **mynodes,
369 			      void *(*dt_alloc)(u64 size, u64 align),
370 			      bool detached)
371 {
372 	int size;
373 	void *mem;
374 	int ret;
375 
376 	if (mynodes)
377 		*mynodes = NULL;
378 
379 	pr_debug(" -> unflatten_device_tree()\n");
380 
381 	if (!blob) {
382 		pr_debug("No device tree pointer\n");
383 		return NULL;
384 	}
385 
386 	pr_debug("Unflattening device tree:\n");
387 	pr_debug("magic: %08x\n", fdt_magic(blob));
388 	pr_debug("size: %08x\n", fdt_totalsize(blob));
389 	pr_debug("version: %08x\n", fdt_version(blob));
390 
391 	if (fdt_check_header(blob)) {
392 		pr_err("Invalid device tree blob header\n");
393 		return NULL;
394 	}
395 
396 	/* First pass, scan for size */
397 	size = unflatten_dt_nodes(blob, NULL, dad, NULL);
398 	if (size <= 0)
399 		return NULL;
400 
401 	size = ALIGN(size, 4);
402 	pr_debug("  size is %d, allocating...\n", size);
403 
404 	/* Allocate memory for the expanded device tree */
405 	mem = dt_alloc(size + 4, __alignof__(struct device_node));
406 	if (!mem)
407 		return NULL;
408 
409 	memset(mem, 0, size);
410 
411 	*(__be32 *)(mem + size) = cpu_to_be32(0xdeadbeef);
412 
413 	pr_debug("  unflattening %p...\n", mem);
414 
415 	/* Second pass, do actual unflattening */
416 	ret = unflatten_dt_nodes(blob, mem, dad, mynodes);
417 
418 	if (be32_to_cpup(mem + size) != 0xdeadbeef)
419 		pr_warn("End of tree marker overwritten: %08x\n",
420 			be32_to_cpup(mem + size));
421 
422 	if (ret <= 0)
423 		return NULL;
424 
425 	if (detached && mynodes && *mynodes) {
426 		of_node_set_flag(*mynodes, OF_DETACHED);
427 		pr_debug("unflattened tree is detached\n");
428 	}
429 
430 	pr_debug(" <- unflatten_device_tree()\n");
431 	return mem;
432 }
433 
kernel_tree_alloc(u64 size,u64 align)434 static void *kernel_tree_alloc(u64 size, u64 align)
435 {
436 	return kzalloc(size, GFP_KERNEL);
437 }
438 
439 static DEFINE_MUTEX(of_fdt_unflatten_mutex);
440 
441 /**
442  * of_fdt_unflatten_tree - create tree of device_nodes from flat blob
443  * @blob: Flat device tree blob
444  * @dad: Parent device node
445  * @mynodes: The device tree created by the call
446  *
447  * unflattens the device-tree passed by the firmware, creating the
448  * tree of struct device_node. It also fills the "name" and "type"
449  * pointers of the nodes so the normal device-tree walking functions
450  * can be used.
451  *
452  * Return: NULL on failure or the memory chunk containing the unflattened
453  * device tree on success.
454  */
of_fdt_unflatten_tree(const unsigned long * blob,struct device_node * dad,struct device_node ** mynodes)455 void *of_fdt_unflatten_tree(const unsigned long *blob,
456 			    struct device_node *dad,
457 			    struct device_node **mynodes)
458 {
459 	void *mem;
460 
461 	mutex_lock(&of_fdt_unflatten_mutex);
462 	mem = __unflatten_device_tree(blob, dad, mynodes, &kernel_tree_alloc,
463 				      true);
464 	mutex_unlock(&of_fdt_unflatten_mutex);
465 
466 	return mem;
467 }
468 EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree);
469 
470 /* Everything below here references initial_boot_params directly. */
471 int __initdata dt_root_addr_cells;
472 int __initdata dt_root_size_cells;
473 
474 void *initial_boot_params __ro_after_init;
475 
476 #ifdef CONFIG_OF_EARLY_FLATTREE
477 
478 static u32 of_fdt_crc32;
479 
early_init_dt_reserve_memory_arch(phys_addr_t base,phys_addr_t size,bool nomap)480 static int __init early_init_dt_reserve_memory_arch(phys_addr_t base,
481 					phys_addr_t size, bool nomap)
482 {
483 	if (nomap) {
484 		/*
485 		 * If the memory is already reserved (by another region), we
486 		 * should not allow it to be marked nomap, but don't worry
487 		 * if the region isn't memory as it won't be mapped.
488 		 */
489 		if (memblock_overlaps_region(&memblock.memory, base, size) &&
490 		    memblock_is_region_reserved(base, size))
491 			return -EBUSY;
492 
493 		return memblock_mark_nomap(base, size);
494 	}
495 	return memblock_reserve(base, size);
496 }
497 
498 /*
499  * __reserved_mem_reserve_reg() - reserve all memory described in 'reg' property
500  */
__reserved_mem_reserve_reg(unsigned long node,const char * uname)501 static int __init __reserved_mem_reserve_reg(unsigned long node,
502 					     const char *uname)
503 {
504 	int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
505 	phys_addr_t base, size;
506 	int len;
507 	const __be32 *prop;
508 	int first = 1;
509 	bool nomap;
510 
511 	prop = of_get_flat_dt_prop(node, "reg", &len);
512 	if (!prop)
513 		return -ENOENT;
514 
515 	if (len && len % t_len != 0) {
516 		pr_err("Reserved memory: invalid reg property in '%s', skipping node.\n",
517 		       uname);
518 		return -EINVAL;
519 	}
520 
521 	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
522 
523 	while (len >= t_len) {
524 		base = dt_mem_next_cell(dt_root_addr_cells, &prop);
525 		size = dt_mem_next_cell(dt_root_size_cells, &prop);
526 
527 		if (size &&
528 		    early_init_dt_reserve_memory_arch(base, size, nomap) == 0) {
529 			pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
530 				uname, &base, (unsigned long)(size / SZ_1M));
531 			if (!nomap)
532 				kmemleak_alloc_phys(base, size, 0, 0);
533 		}
534 		else
535 			pr_info("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
536 				uname, &base, (unsigned long)(size / SZ_1M));
537 
538 		len -= t_len;
539 		if (first) {
540 			fdt_reserved_mem_save_node(node, uname, base, size);
541 			first = 0;
542 		}
543 	}
544 	return 0;
545 }
546 
547 /*
548  * __reserved_mem_check_root() - check if #size-cells, #address-cells provided
549  * in /reserved-memory matches the values supported by the current implementation,
550  * also check if ranges property has been provided
551  */
__reserved_mem_check_root(unsigned long node)552 static int __init __reserved_mem_check_root(unsigned long node)
553 {
554 	const __be32 *prop;
555 
556 	prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
557 	if (!prop || be32_to_cpup(prop) != dt_root_size_cells)
558 		return -EINVAL;
559 
560 	prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
561 	if (!prop || be32_to_cpup(prop) != dt_root_addr_cells)
562 		return -EINVAL;
563 
564 	prop = of_get_flat_dt_prop(node, "ranges", NULL);
565 	if (!prop)
566 		return -EINVAL;
567 	return 0;
568 }
569 
570 /*
571  * fdt_scan_reserved_mem() - scan a single FDT node for reserved memory
572  */
fdt_scan_reserved_mem(void)573 static int __init fdt_scan_reserved_mem(void)
574 {
575 	int node, child;
576 	const void *fdt = initial_boot_params;
577 
578 	node = fdt_path_offset(fdt, "/reserved-memory");
579 	if (node < 0)
580 		return -ENODEV;
581 
582 	if (__reserved_mem_check_root(node) != 0) {
583 		pr_err("Reserved memory: unsupported node format, ignoring\n");
584 		return -EINVAL;
585 	}
586 
587 	fdt_for_each_subnode(child, fdt, node) {
588 		const char *uname;
589 		int err;
590 
591 		if (!of_fdt_device_is_available(fdt, child))
592 			continue;
593 
594 		uname = fdt_get_name(fdt, child, NULL);
595 
596 		err = __reserved_mem_reserve_reg(child, uname);
597 		if (err == -ENOENT && of_get_flat_dt_prop(child, "size", NULL))
598 			fdt_reserved_mem_save_node(child, uname, 0, 0);
599 	}
600 	return 0;
601 }
602 
603 /*
604  * fdt_reserve_elfcorehdr() - reserves memory for elf core header
605  *
606  * This function reserves the memory occupied by an elf core header
607  * described in the device tree. This region contains all the
608  * information about primary kernel's core image and is used by a dump
609  * capture kernel to access the system memory on primary kernel.
610  */
fdt_reserve_elfcorehdr(void)611 static void __init fdt_reserve_elfcorehdr(void)
612 {
613 	if (!IS_ENABLED(CONFIG_CRASH_DUMP) || !elfcorehdr_size)
614 		return;
615 
616 	if (memblock_is_region_reserved(elfcorehdr_addr, elfcorehdr_size)) {
617 		pr_warn("elfcorehdr is overlapped\n");
618 		return;
619 	}
620 
621 	memblock_reserve(elfcorehdr_addr, elfcorehdr_size);
622 
623 	pr_info("Reserving %llu KiB of memory at 0x%llx for elfcorehdr\n",
624 		elfcorehdr_size >> 10, elfcorehdr_addr);
625 }
626 
627 /**
628  * early_init_fdt_scan_reserved_mem() - create reserved memory regions
629  *
630  * This function grabs memory from early allocator for device exclusive use
631  * defined in device tree structures. It should be called by arch specific code
632  * once the early allocator (i.e. memblock) has been fully activated.
633  */
early_init_fdt_scan_reserved_mem(void)634 void __init early_init_fdt_scan_reserved_mem(void)
635 {
636 	int n;
637 	u64 base, size;
638 
639 	if (!initial_boot_params)
640 		return;
641 
642 	/* Process header /memreserve/ fields */
643 	for (n = 0; ; n++) {
644 		fdt_get_mem_rsv(initial_boot_params, n, &base, &size);
645 		if (!size)
646 			break;
647 		early_init_dt_reserve_memory_arch(base, size, false);
648 	}
649 
650 	fdt_scan_reserved_mem();
651 	fdt_reserve_elfcorehdr();
652 	fdt_init_reserved_mem();
653 }
654 
655 /**
656  * early_init_fdt_reserve_self() - reserve the memory used by the FDT blob
657  */
early_init_fdt_reserve_self(void)658 void __init early_init_fdt_reserve_self(void)
659 {
660 	if (!initial_boot_params)
661 		return;
662 
663 	/* Reserve the dtb region */
664 	early_init_dt_reserve_memory_arch(__pa(initial_boot_params),
665 					  fdt_totalsize(initial_boot_params),
666 					  false);
667 }
668 
669 /**
670  * of_scan_flat_dt - scan flattened tree blob and call callback on each.
671  * @it: callback function
672  * @data: context data pointer
673  *
674  * This function is used to scan the flattened device-tree, it is
675  * used to extract the memory information at boot before we can
676  * unflatten the tree
677  */
of_scan_flat_dt(int (* it)(unsigned long node,const char * uname,int depth,void * data),void * data)678 int __init of_scan_flat_dt(int (*it)(unsigned long node,
679 				     const char *uname, int depth,
680 				     void *data),
681 			   void *data)
682 {
683 	const void *blob = initial_boot_params;
684 	const char *pathp;
685 	int offset, rc = 0, depth = -1;
686 
687 	if (!blob)
688 		return 0;
689 
690 	for (offset = fdt_next_node(blob, -1, &depth);
691 	     offset >= 0 && depth >= 0 && !rc;
692 	     offset = fdt_next_node(blob, offset, &depth)) {
693 
694 		pathp = fdt_get_name(blob, offset, NULL);
695 		rc = it(offset, pathp, depth, data);
696 	}
697 	return rc;
698 }
699 
700 /**
701  * of_scan_flat_dt_subnodes - scan sub-nodes of a node call callback on each.
702  * @parent: parent node
703  * @it: callback function
704  * @data: context data pointer
705  *
706  * This function is used to scan sub-nodes of a node.
707  */
of_scan_flat_dt_subnodes(unsigned long parent,int (* it)(unsigned long node,const char * uname,void * data),void * data)708 int __init of_scan_flat_dt_subnodes(unsigned long parent,
709 				    int (*it)(unsigned long node,
710 					      const char *uname,
711 					      void *data),
712 				    void *data)
713 {
714 	const void *blob = initial_boot_params;
715 	int node;
716 
717 	fdt_for_each_subnode(node, blob, parent) {
718 		const char *pathp;
719 		int rc;
720 
721 		pathp = fdt_get_name(blob, node, NULL);
722 		rc = it(node, pathp, data);
723 		if (rc)
724 			return rc;
725 	}
726 	return 0;
727 }
728 
729 /**
730  * of_get_flat_dt_subnode_by_name - get the subnode by given name
731  *
732  * @node: the parent node
733  * @uname: the name of subnode
734  * @return offset of the subnode, or -FDT_ERR_NOTFOUND if there is none
735  */
736 
of_get_flat_dt_subnode_by_name(unsigned long node,const char * uname)737 int __init of_get_flat_dt_subnode_by_name(unsigned long node, const char *uname)
738 {
739 	return fdt_subnode_offset(initial_boot_params, node, uname);
740 }
741 
742 /*
743  * of_get_flat_dt_root - find the root node in the flat blob
744  */
of_get_flat_dt_root(void)745 unsigned long __init of_get_flat_dt_root(void)
746 {
747 	return 0;
748 }
749 
750 /*
751  * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
752  *
753  * This function can be used within scan_flattened_dt callback to get
754  * access to properties
755  */
of_get_flat_dt_prop(unsigned long node,const char * name,int * size)756 const void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
757 				       int *size)
758 {
759 	return fdt_getprop(initial_boot_params, node, name, size);
760 }
761 
762 /**
763  * of_fdt_is_compatible - Return true if given node from the given blob has
764  * compat in its compatible list
765  * @blob: A device tree blob
766  * @node: node to test
767  * @compat: compatible string to compare with compatible list.
768  *
769  * Return: a non-zero value on match with smaller values returned for more
770  * specific compatible values.
771  */
of_fdt_is_compatible(const void * blob,unsigned long node,const char * compat)772 static int of_fdt_is_compatible(const void *blob,
773 		      unsigned long node, const char *compat)
774 {
775 	const char *cp;
776 	int cplen;
777 	unsigned long l, score = 0;
778 
779 	cp = fdt_getprop(blob, node, "compatible", &cplen);
780 	if (cp == NULL)
781 		return 0;
782 	while (cplen > 0) {
783 		score++;
784 		if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
785 			return score;
786 		l = strlen(cp) + 1;
787 		cp += l;
788 		cplen -= l;
789 	}
790 
791 	return 0;
792 }
793 
794 /**
795  * of_flat_dt_is_compatible - Return true if given node has compat in compatible list
796  * @node: node to test
797  * @compat: compatible string to compare with compatible list.
798  */
of_flat_dt_is_compatible(unsigned long node,const char * compat)799 int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
800 {
801 	return of_fdt_is_compatible(initial_boot_params, node, compat);
802 }
803 
804 /*
805  * of_flat_dt_match - Return true if node matches a list of compatible values
806  */
of_flat_dt_match(unsigned long node,const char * const * compat)807 static int __init of_flat_dt_match(unsigned long node, const char *const *compat)
808 {
809 	unsigned int tmp, score = 0;
810 
811 	if (!compat)
812 		return 0;
813 
814 	while (*compat) {
815 		tmp = of_fdt_is_compatible(initial_boot_params, node, *compat);
816 		if (tmp && (score == 0 || (tmp < score)))
817 			score = tmp;
818 		compat++;
819 	}
820 
821 	return score;
822 }
823 
824 /*
825  * of_get_flat_dt_phandle - Given a node in the flat blob, return the phandle
826  */
of_get_flat_dt_phandle(unsigned long node)827 uint32_t __init of_get_flat_dt_phandle(unsigned long node)
828 {
829 	return fdt_get_phandle(initial_boot_params, node);
830 }
831 
832 struct fdt_scan_status {
833 	const char *name;
834 	int namelen;
835 	int depth;
836 	int found;
837 	int (*iterator)(unsigned long node, const char *uname, int depth, void *data);
838 	void *data;
839 };
840 
of_flat_dt_get_machine_name(void)841 const char * __init of_flat_dt_get_machine_name(void)
842 {
843 	const char *name;
844 	unsigned long dt_root = of_get_flat_dt_root();
845 
846 	name = of_get_flat_dt_prop(dt_root, "model", NULL);
847 	if (!name)
848 		name = of_get_flat_dt_prop(dt_root, "compatible", NULL);
849 	return name;
850 }
851 
852 /**
853  * of_flat_dt_match_machine - Iterate match tables to find matching machine.
854  *
855  * @default_match: A machine specific ptr to return in case of no match.
856  * @get_next_compat: callback function to return next compatible match table.
857  *
858  * Iterate through machine match tables to find the best match for the machine
859  * compatible string in the FDT.
860  */
of_flat_dt_match_machine(const void * default_match,const void * (* get_next_compat)(const char * const **))861 const void * __init of_flat_dt_match_machine(const void *default_match,
862 		const void * (*get_next_compat)(const char * const**))
863 {
864 	const void *data = NULL;
865 	const void *best_data = default_match;
866 	const char *const *compat;
867 	unsigned long dt_root;
868 	unsigned int best_score = ~1, score = 0;
869 
870 	dt_root = of_get_flat_dt_root();
871 	while ((data = get_next_compat(&compat))) {
872 		score = of_flat_dt_match(dt_root, compat);
873 		if (score > 0 && score < best_score) {
874 			best_data = data;
875 			best_score = score;
876 		}
877 	}
878 	if (!best_data) {
879 		const char *prop;
880 		int size;
881 
882 		pr_err("\n unrecognized device tree list:\n[ ");
883 
884 		prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
885 		if (prop) {
886 			while (size > 0) {
887 				printk("'%s' ", prop);
888 				size -= strlen(prop) + 1;
889 				prop += strlen(prop) + 1;
890 			}
891 		}
892 		printk("]\n\n");
893 		return NULL;
894 	}
895 
896 	pr_info("Machine model: %s\n", of_flat_dt_get_machine_name());
897 
898 	return best_data;
899 }
900 
__early_init_dt_declare_initrd(unsigned long start,unsigned long end)901 static void __early_init_dt_declare_initrd(unsigned long start,
902 					   unsigned long end)
903 {
904 	/* ARM64 would cause a BUG to occur here when CONFIG_DEBUG_VM is
905 	 * enabled since __va() is called too early. ARM64 does make use
906 	 * of phys_initrd_start/phys_initrd_size so we can skip this
907 	 * conversion.
908 	 */
909 	if (!IS_ENABLED(CONFIG_ARM64)) {
910 		initrd_start = (unsigned long)__va(start);
911 		initrd_end = (unsigned long)__va(end);
912 		initrd_below_start_ok = 1;
913 	}
914 }
915 
916 /**
917  * early_init_dt_check_for_initrd - Decode initrd location from flat tree
918  * @node: reference to node containing initrd location ('chosen')
919  */
early_init_dt_check_for_initrd(unsigned long node)920 static void __init early_init_dt_check_for_initrd(unsigned long node)
921 {
922 	u64 start, end;
923 	int len;
924 	const __be32 *prop;
925 
926 	if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD))
927 		return;
928 
929 	pr_debug("Looking for initrd properties... ");
930 
931 	prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);
932 	if (!prop)
933 		return;
934 	start = of_read_number(prop, len/4);
935 
936 	prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
937 	if (!prop)
938 		return;
939 	end = of_read_number(prop, len/4);
940 
941 	__early_init_dt_declare_initrd(start, end);
942 	phys_initrd_start = start;
943 	phys_initrd_size = end - start;
944 
945 	pr_debug("initrd_start=0x%llx  initrd_end=0x%llx\n", start, end);
946 }
947 
948 /**
949  * early_init_dt_check_for_elfcorehdr - Decode elfcorehdr location from flat
950  * tree
951  * @node: reference to node containing elfcorehdr location ('chosen')
952  */
early_init_dt_check_for_elfcorehdr(unsigned long node)953 static void __init early_init_dt_check_for_elfcorehdr(unsigned long node)
954 {
955 	const __be32 *prop;
956 	int len;
957 
958 	if (!IS_ENABLED(CONFIG_CRASH_DUMP))
959 		return;
960 
961 	pr_debug("Looking for elfcorehdr property... ");
962 
963 	prop = of_get_flat_dt_prop(node, "linux,elfcorehdr", &len);
964 	if (!prop || (len < (dt_root_addr_cells + dt_root_size_cells)))
965 		return;
966 
967 	elfcorehdr_addr = dt_mem_next_cell(dt_root_addr_cells, &prop);
968 	elfcorehdr_size = dt_mem_next_cell(dt_root_size_cells, &prop);
969 
970 	pr_debug("elfcorehdr_start=0x%llx elfcorehdr_size=0x%llx\n",
971 		 elfcorehdr_addr, elfcorehdr_size);
972 }
973 
974 static unsigned long chosen_node_offset = -FDT_ERR_NOTFOUND;
975 
976 /*
977  * The main usage of linux,usable-memory-range is for crash dump kernel.
978  * Originally, the number of usable-memory regions is one. Now there may
979  * be two regions, low region and high region.
980  * To make compatibility with existing user-space and older kdump, the low
981  * region is always the last range of linux,usable-memory-range if exist.
982  */
983 #define MAX_USABLE_RANGES		2
984 
985 /**
986  * early_init_dt_check_for_usable_mem_range - Decode usable memory range
987  * location from flat tree
988  */
early_init_dt_check_for_usable_mem_range(void)989 void __init early_init_dt_check_for_usable_mem_range(void)
990 {
991 	struct memblock_region rgn[MAX_USABLE_RANGES] = {0};
992 	const __be32 *prop, *endp;
993 	int len, i;
994 	unsigned long node = chosen_node_offset;
995 
996 	if ((long)node < 0)
997 		return;
998 
999 	pr_debug("Looking for usable-memory-range property... ");
1000 
1001 	prop = of_get_flat_dt_prop(node, "linux,usable-memory-range", &len);
1002 	if (!prop || (len % (dt_root_addr_cells + dt_root_size_cells)))
1003 		return;
1004 
1005 	endp = prop + (len / sizeof(__be32));
1006 	for (i = 0; i < MAX_USABLE_RANGES && prop < endp; i++) {
1007 		rgn[i].base = dt_mem_next_cell(dt_root_addr_cells, &prop);
1008 		rgn[i].size = dt_mem_next_cell(dt_root_size_cells, &prop);
1009 
1010 		pr_debug("cap_mem_regions[%d]: base=%pa, size=%pa\n",
1011 			 i, &rgn[i].base, &rgn[i].size);
1012 	}
1013 
1014 	memblock_cap_memory_range(rgn[0].base, rgn[0].size);
1015 	for (i = 1; i < MAX_USABLE_RANGES && rgn[i].size; i++)
1016 		memblock_add(rgn[i].base, rgn[i].size);
1017 }
1018 
1019 #ifdef CONFIG_SERIAL_EARLYCON
1020 
early_init_dt_scan_chosen_stdout(void)1021 int __init early_init_dt_scan_chosen_stdout(void)
1022 {
1023 	int offset;
1024 	const char *p, *q, *options = NULL;
1025 	int l;
1026 	const struct earlycon_id *match;
1027 	const void *fdt = initial_boot_params;
1028 
1029 	offset = fdt_path_offset(fdt, "/chosen");
1030 	if (offset < 0)
1031 		offset = fdt_path_offset(fdt, "/chosen@0");
1032 	if (offset < 0)
1033 		return -ENOENT;
1034 
1035 	p = fdt_getprop(fdt, offset, "stdout-path", &l);
1036 	if (!p)
1037 		p = fdt_getprop(fdt, offset, "linux,stdout-path", &l);
1038 	if (!p || !l)
1039 		return -ENOENT;
1040 
1041 	q = strchrnul(p, ':');
1042 	if (*q != '\0')
1043 		options = q + 1;
1044 	l = q - p;
1045 
1046 	/* Get the node specified by stdout-path */
1047 	offset = fdt_path_offset_namelen(fdt, p, l);
1048 	if (offset < 0) {
1049 		pr_warn("earlycon: stdout-path %.*s not found\n", l, p);
1050 		return 0;
1051 	}
1052 
1053 	for (match = __earlycon_table; match < __earlycon_table_end; match++) {
1054 		if (!match->compatible[0])
1055 			continue;
1056 
1057 		if (fdt_node_check_compatible(fdt, offset, match->compatible))
1058 			continue;
1059 
1060 		if (of_setup_earlycon(match, offset, options) == 0)
1061 			return 0;
1062 	}
1063 	return -ENODEV;
1064 }
1065 #endif
1066 
1067 /*
1068  * early_init_dt_scan_root - fetch the top level address and size cells
1069  */
early_init_dt_scan_root(void)1070 int __init early_init_dt_scan_root(void)
1071 {
1072 	const __be32 *prop;
1073 	const void *fdt = initial_boot_params;
1074 	int node = fdt_path_offset(fdt, "/");
1075 
1076 	if (node < 0)
1077 		return -ENODEV;
1078 
1079 	dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
1080 	dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
1081 
1082 	prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
1083 	if (prop)
1084 		dt_root_size_cells = be32_to_cpup(prop);
1085 	pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells);
1086 
1087 	prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
1088 	if (prop)
1089 		dt_root_addr_cells = be32_to_cpup(prop);
1090 	pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells);
1091 
1092 	return 0;
1093 }
1094 
dt_mem_next_cell(int s,const __be32 ** cellp)1095 u64 __init dt_mem_next_cell(int s, const __be32 **cellp)
1096 {
1097 	const __be32 *p = *cellp;
1098 
1099 	*cellp = p + s;
1100 	return of_read_number(p, s);
1101 }
1102 
1103 /*
1104  * early_init_dt_scan_memory - Look for and parse memory nodes
1105  */
early_init_dt_scan_memory(void)1106 int __init early_init_dt_scan_memory(void)
1107 {
1108 	int node;
1109 	const void *fdt = initial_boot_params;
1110 
1111 	fdt_for_each_subnode(node, fdt, 0) {
1112 		const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
1113 		const __be32 *reg, *endp;
1114 		int l;
1115 		bool hotpluggable;
1116 
1117 		/* We are scanning "memory" nodes only */
1118 		if (type == NULL || strcmp(type, "memory") != 0)
1119 			continue;
1120 
1121 		if (!of_fdt_device_is_available(fdt, node))
1122 			continue;
1123 
1124 		reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
1125 		if (reg == NULL)
1126 			reg = of_get_flat_dt_prop(node, "reg", &l);
1127 		if (reg == NULL)
1128 			continue;
1129 
1130 		endp = reg + (l / sizeof(__be32));
1131 		hotpluggable = of_get_flat_dt_prop(node, "hotpluggable", NULL);
1132 
1133 		pr_debug("memory scan node %s, reg size %d,\n",
1134 			 fdt_get_name(fdt, node, NULL), l);
1135 
1136 		while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
1137 			u64 base, size;
1138 
1139 			base = dt_mem_next_cell(dt_root_addr_cells, &reg);
1140 			size = dt_mem_next_cell(dt_root_size_cells, &reg);
1141 
1142 			if (size == 0)
1143 				continue;
1144 			pr_debug(" - %llx, %llx\n", base, size);
1145 
1146 			early_init_dt_add_memory_arch(base, size);
1147 
1148 			if (!hotpluggable)
1149 				continue;
1150 
1151 			if (memblock_mark_hotplug(base, size))
1152 				pr_warn("failed to mark hotplug range 0x%llx - 0x%llx\n",
1153 					base, base + size);
1154 		}
1155 	}
1156 	return 0;
1157 }
1158 
early_init_dt_scan_chosen(char * cmdline)1159 int __init early_init_dt_scan_chosen(char *cmdline)
1160 {
1161 	int l, node;
1162 	const char *p;
1163 	const void *rng_seed;
1164 	const void *fdt = initial_boot_params;
1165 
1166 	node = fdt_path_offset(fdt, "/chosen");
1167 	if (node < 0)
1168 		node = fdt_path_offset(fdt, "/chosen@0");
1169 	if (node < 0)
1170 		return -ENOENT;
1171 
1172 	chosen_node_offset = node;
1173 
1174 	early_init_dt_check_for_initrd(node);
1175 	early_init_dt_check_for_elfcorehdr(node);
1176 
1177 	/* Retrieve command line */
1178 	p = of_get_flat_dt_prop(node, "bootargs", &l);
1179 	if (p != NULL && l > 0)
1180 		strlcpy(cmdline, p, min(l, COMMAND_LINE_SIZE));
1181 
1182 	/*
1183 	 * CONFIG_CMDLINE is meant to be a default in case nothing else
1184 	 * managed to set the command line, unless CONFIG_CMDLINE_FORCE
1185 	 * is set in which case we override whatever was found earlier.
1186 	 */
1187 #ifdef CONFIG_CMDLINE
1188 #if defined(CONFIG_CMDLINE_EXTEND)
1189 	strlcat(cmdline, " ", COMMAND_LINE_SIZE);
1190 	strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1191 #elif defined(CONFIG_CMDLINE_FORCE)
1192 	strlcpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1193 #else
1194 	/* No arguments from boot loader, use kernel's  cmdl*/
1195 	if (!((char *)cmdline)[0])
1196 		strlcpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1197 #endif
1198 #endif /* CONFIG_CMDLINE */
1199 
1200 	pr_debug("Command line is: %s\n", (char *)cmdline);
1201 
1202 	rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l);
1203 	if (rng_seed && l > 0) {
1204 		add_bootloader_randomness(rng_seed, l);
1205 
1206 		/* try to clear seed so it won't be found. */
1207 		fdt_nop_property(initial_boot_params, node, "rng-seed");
1208 
1209 		/* update CRC check value */
1210 		of_fdt_crc32 = crc32_be(~0, initial_boot_params,
1211 				fdt_totalsize(initial_boot_params));
1212 	}
1213 
1214 	return 0;
1215 }
1216 
1217 #ifndef MIN_MEMBLOCK_ADDR
1218 #define MIN_MEMBLOCK_ADDR	__pa(PAGE_OFFSET)
1219 #endif
1220 #ifndef MAX_MEMBLOCK_ADDR
1221 #define MAX_MEMBLOCK_ADDR	((phys_addr_t)~0)
1222 #endif
1223 
early_init_dt_add_memory_arch(u64 base,u64 size)1224 void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
1225 {
1226 	const u64 phys_offset = MIN_MEMBLOCK_ADDR;
1227 
1228 	if (size < PAGE_SIZE - (base & ~PAGE_MASK)) {
1229 		pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
1230 			base, base + size);
1231 		return;
1232 	}
1233 
1234 	if (!PAGE_ALIGNED(base)) {
1235 		size -= PAGE_SIZE - (base & ~PAGE_MASK);
1236 		base = PAGE_ALIGN(base);
1237 	}
1238 	size &= PAGE_MASK;
1239 
1240 	if (base > MAX_MEMBLOCK_ADDR) {
1241 		pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
1242 			base, base + size);
1243 		return;
1244 	}
1245 
1246 	if (base + size - 1 > MAX_MEMBLOCK_ADDR) {
1247 		pr_warn("Ignoring memory range 0x%llx - 0x%llx\n",
1248 			((u64)MAX_MEMBLOCK_ADDR) + 1, base + size);
1249 		size = MAX_MEMBLOCK_ADDR - base + 1;
1250 	}
1251 
1252 	if (base + size < phys_offset) {
1253 		pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
1254 			base, base + size);
1255 		return;
1256 	}
1257 	if (base < phys_offset) {
1258 		pr_warn("Ignoring memory range 0x%llx - 0x%llx\n",
1259 			base, phys_offset);
1260 		size -= phys_offset - base;
1261 		base = phys_offset;
1262 	}
1263 	memblock_add(base, size);
1264 }
1265 
early_init_dt_alloc_memory_arch(u64 size,u64 align)1266 static void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
1267 {
1268 	void *ptr = memblock_alloc(size, align);
1269 
1270 	if (!ptr)
1271 		panic("%s: Failed to allocate %llu bytes align=0x%llx\n",
1272 		      __func__, size, align);
1273 
1274 	return ptr;
1275 }
1276 
early_init_dt_verify(void * params)1277 bool __init early_init_dt_verify(void *params)
1278 {
1279 	if (!params)
1280 		return false;
1281 
1282 	/* check device tree validity */
1283 	if (fdt_check_header(params))
1284 		return false;
1285 
1286 	/* Setup flat device-tree pointer */
1287 	initial_boot_params = params;
1288 	of_fdt_crc32 = crc32_be(~0, initial_boot_params,
1289 				fdt_totalsize(initial_boot_params));
1290 	return true;
1291 }
1292 
1293 
early_init_dt_scan_nodes(void)1294 void __init early_init_dt_scan_nodes(void)
1295 {
1296 	int rc;
1297 
1298 	/* Initialize {size,address}-cells info */
1299 	early_init_dt_scan_root();
1300 
1301 	/* Retrieve various information from the /chosen node */
1302 	rc = early_init_dt_scan_chosen(boot_command_line);
1303 	if (rc)
1304 		pr_warn("No chosen node found, continuing without\n");
1305 
1306 	/* Setup memory, calling early_init_dt_add_memory_arch */
1307 	early_init_dt_scan_memory();
1308 
1309 	/* Handle linux,usable-memory-range property */
1310 	early_init_dt_check_for_usable_mem_range();
1311 }
1312 
early_init_dt_scan(void * params)1313 bool __init early_init_dt_scan(void *params)
1314 {
1315 	bool status;
1316 
1317 	status = early_init_dt_verify(params);
1318 	if (!status)
1319 		return false;
1320 
1321 	early_init_dt_scan_nodes();
1322 	return true;
1323 }
1324 
1325 /**
1326  * unflatten_device_tree - create tree of device_nodes from flat blob
1327  *
1328  * unflattens the device-tree passed by the firmware, creating the
1329  * tree of struct device_node. It also fills the "name" and "type"
1330  * pointers of the nodes so the normal device-tree walking functions
1331  * can be used.
1332  */
unflatten_device_tree(void)1333 void __init unflatten_device_tree(void)
1334 {
1335 	__unflatten_device_tree(initial_boot_params, NULL, &of_root,
1336 				early_init_dt_alloc_memory_arch, false);
1337 
1338 	/* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */
1339 	of_alias_scan(early_init_dt_alloc_memory_arch);
1340 
1341 	unittest_unflatten_overlay_base();
1342 }
1343 
1344 /**
1345  * unflatten_and_copy_device_tree - copy and create tree of device_nodes from flat blob
1346  *
1347  * Copies and unflattens the device-tree passed by the firmware, creating the
1348  * tree of struct device_node. It also fills the "name" and "type"
1349  * pointers of the nodes so the normal device-tree walking functions
1350  * can be used. This should only be used when the FDT memory has not been
1351  * reserved such is the case when the FDT is built-in to the kernel init
1352  * section. If the FDT memory is reserved already then unflatten_device_tree
1353  * should be used instead.
1354  */
unflatten_and_copy_device_tree(void)1355 void __init unflatten_and_copy_device_tree(void)
1356 {
1357 	int size;
1358 	void *dt;
1359 
1360 	if (!initial_boot_params) {
1361 		pr_warn("No valid device tree found, continuing without\n");
1362 		return;
1363 	}
1364 
1365 	size = fdt_totalsize(initial_boot_params);
1366 	dt = early_init_dt_alloc_memory_arch(size,
1367 					     roundup_pow_of_two(FDT_V17_SIZE));
1368 
1369 	if (dt) {
1370 		memcpy(dt, initial_boot_params, size);
1371 		initial_boot_params = dt;
1372 	}
1373 	unflatten_device_tree();
1374 }
1375 
1376 #ifdef CONFIG_SYSFS
of_fdt_raw_read(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)1377 static ssize_t of_fdt_raw_read(struct file *filp, struct kobject *kobj,
1378 			       struct bin_attribute *bin_attr,
1379 			       char *buf, loff_t off, size_t count)
1380 {
1381 	memcpy(buf, initial_boot_params + off, count);
1382 	return count;
1383 }
1384 
of_fdt_raw_init(void)1385 static int __init of_fdt_raw_init(void)
1386 {
1387 	static struct bin_attribute of_fdt_raw_attr =
1388 		__BIN_ATTR(fdt, S_IRUSR, of_fdt_raw_read, NULL, 0);
1389 
1390 	if (!initial_boot_params)
1391 		return 0;
1392 
1393 	if (of_fdt_crc32 != crc32_be(~0, initial_boot_params,
1394 				     fdt_totalsize(initial_boot_params))) {
1395 		pr_warn("not creating '/sys/firmware/fdt': CRC check failed\n");
1396 		return 0;
1397 	}
1398 	of_fdt_raw_attr.size = fdt_totalsize(initial_boot_params);
1399 	return sysfs_create_bin_file(firmware_kobj, &of_fdt_raw_attr);
1400 }
1401 late_initcall(of_fdt_raw_init);
1402 #endif
1403 
1404 #endif /* CONFIG_OF_EARLY_FLATTREE */
1405