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 - 1))
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(phys_addr_t base,phys_addr_t size,bool nomap)480 static int __init early_init_dt_reserve_memory(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(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);
533 		}
534 		else
535 			pr_err("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 		memblock_reserve(base, size);
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 	memblock_reserve(__pa(initial_boot_params),
665 			 fdt_totalsize(initial_boot_params));
666 }
667 
668 /**
669  * of_scan_flat_dt - scan flattened tree blob and call callback on each.
670  * @it: callback function
671  * @data: context data pointer
672  *
673  * This function is used to scan the flattened device-tree, it is
674  * used to extract the memory information at boot before we can
675  * unflatten the tree
676  */
of_scan_flat_dt(int (* it)(unsigned long node,const char * uname,int depth,void * data),void * data)677 int __init of_scan_flat_dt(int (*it)(unsigned long node,
678 				     const char *uname, int depth,
679 				     void *data),
680 			   void *data)
681 {
682 	const void *blob = initial_boot_params;
683 	const char *pathp;
684 	int offset, rc = 0, depth = -1;
685 
686 	if (!blob)
687 		return 0;
688 
689 	for (offset = fdt_next_node(blob, -1, &depth);
690 	     offset >= 0 && depth >= 0 && !rc;
691 	     offset = fdt_next_node(blob, offset, &depth)) {
692 
693 		pathp = fdt_get_name(blob, offset, NULL);
694 		rc = it(offset, pathp, depth, data);
695 	}
696 	return rc;
697 }
698 
699 /**
700  * of_scan_flat_dt_subnodes - scan sub-nodes of a node call callback on each.
701  * @parent: parent node
702  * @it: callback function
703  * @data: context data pointer
704  *
705  * This function is used to scan sub-nodes of a node.
706  */
of_scan_flat_dt_subnodes(unsigned long parent,int (* it)(unsigned long node,const char * uname,void * data),void * data)707 int __init of_scan_flat_dt_subnodes(unsigned long parent,
708 				    int (*it)(unsigned long node,
709 					      const char *uname,
710 					      void *data),
711 				    void *data)
712 {
713 	const void *blob = initial_boot_params;
714 	int node;
715 
716 	fdt_for_each_subnode(node, blob, parent) {
717 		const char *pathp;
718 		int rc;
719 
720 		pathp = fdt_get_name(blob, node, NULL);
721 		rc = it(node, pathp, data);
722 		if (rc)
723 			return rc;
724 	}
725 	return 0;
726 }
727 
728 /**
729  * of_get_flat_dt_subnode_by_name - get the subnode by given name
730  *
731  * @node: the parent node
732  * @uname: the name of subnode
733  * @return offset of the subnode, or -FDT_ERR_NOTFOUND if there is none
734  */
735 
of_get_flat_dt_subnode_by_name(unsigned long node,const char * uname)736 int __init of_get_flat_dt_subnode_by_name(unsigned long node, const char *uname)
737 {
738 	return fdt_subnode_offset(initial_boot_params, node, uname);
739 }
740 
741 /*
742  * of_get_flat_dt_root - find the root node in the flat blob
743  */
of_get_flat_dt_root(void)744 unsigned long __init of_get_flat_dt_root(void)
745 {
746 	return 0;
747 }
748 
749 /*
750  * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
751  *
752  * This function can be used within scan_flattened_dt callback to get
753  * access to properties
754  */
of_get_flat_dt_prop(unsigned long node,const char * name,int * size)755 const void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
756 				       int *size)
757 {
758 	return fdt_getprop(initial_boot_params, node, name, size);
759 }
760 
761 /**
762  * of_fdt_is_compatible - Return true if given node from the given blob has
763  * compat in its compatible list
764  * @blob: A device tree blob
765  * @node: node to test
766  * @compat: compatible string to compare with compatible list.
767  *
768  * Return: a non-zero value on match with smaller values returned for more
769  * specific compatible values.
770  */
of_fdt_is_compatible(const void * blob,unsigned long node,const char * compat)771 static int of_fdt_is_compatible(const void *blob,
772 		      unsigned long node, const char *compat)
773 {
774 	const char *cp;
775 	int cplen;
776 	unsigned long l, score = 0;
777 
778 	cp = fdt_getprop(blob, node, "compatible", &cplen);
779 	if (cp == NULL)
780 		return 0;
781 	while (cplen > 0) {
782 		score++;
783 		if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
784 			return score;
785 		l = strlen(cp) + 1;
786 		cp += l;
787 		cplen -= l;
788 	}
789 
790 	return 0;
791 }
792 
793 /**
794  * of_flat_dt_is_compatible - Return true if given node has compat in compatible list
795  * @node: node to test
796  * @compat: compatible string to compare with compatible list.
797  */
of_flat_dt_is_compatible(unsigned long node,const char * compat)798 int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
799 {
800 	return of_fdt_is_compatible(initial_boot_params, node, compat);
801 }
802 
803 /*
804  * of_flat_dt_match - Return true if node matches a list of compatible values
805  */
of_flat_dt_match(unsigned long node,const char * const * compat)806 static int __init of_flat_dt_match(unsigned long node, const char *const *compat)
807 {
808 	unsigned int tmp, score = 0;
809 
810 	if (!compat)
811 		return 0;
812 
813 	while (*compat) {
814 		tmp = of_fdt_is_compatible(initial_boot_params, node, *compat);
815 		if (tmp && (score == 0 || (tmp < score)))
816 			score = tmp;
817 		compat++;
818 	}
819 
820 	return score;
821 }
822 
823 /*
824  * of_get_flat_dt_phandle - Given a node in the flat blob, return the phandle
825  */
of_get_flat_dt_phandle(unsigned long node)826 uint32_t __init of_get_flat_dt_phandle(unsigned long node)
827 {
828 	return fdt_get_phandle(initial_boot_params, node);
829 }
830 
of_flat_dt_get_machine_name(void)831 const char * __init of_flat_dt_get_machine_name(void)
832 {
833 	const char *name;
834 	unsigned long dt_root = of_get_flat_dt_root();
835 
836 	name = of_get_flat_dt_prop(dt_root, "model", NULL);
837 	if (!name)
838 		name = of_get_flat_dt_prop(dt_root, "compatible", NULL);
839 	return name;
840 }
841 
842 /**
843  * of_flat_dt_match_machine - Iterate match tables to find matching machine.
844  *
845  * @default_match: A machine specific ptr to return in case of no match.
846  * @get_next_compat: callback function to return next compatible match table.
847  *
848  * Iterate through machine match tables to find the best match for the machine
849  * compatible string in the FDT.
850  */
of_flat_dt_match_machine(const void * default_match,const void * (* get_next_compat)(const char * const **))851 const void * __init of_flat_dt_match_machine(const void *default_match,
852 		const void * (*get_next_compat)(const char * const**))
853 {
854 	const void *data = NULL;
855 	const void *best_data = default_match;
856 	const char *const *compat;
857 	unsigned long dt_root;
858 	unsigned int best_score = ~1, score = 0;
859 
860 	dt_root = of_get_flat_dt_root();
861 	while ((data = get_next_compat(&compat))) {
862 		score = of_flat_dt_match(dt_root, compat);
863 		if (score > 0 && score < best_score) {
864 			best_data = data;
865 			best_score = score;
866 		}
867 	}
868 	if (!best_data) {
869 		const char *prop;
870 		int size;
871 
872 		pr_err("\n unrecognized device tree list:\n[ ");
873 
874 		prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
875 		if (prop) {
876 			while (size > 0) {
877 				printk("'%s' ", prop);
878 				size -= strlen(prop) + 1;
879 				prop += strlen(prop) + 1;
880 			}
881 		}
882 		printk("]\n\n");
883 		return NULL;
884 	}
885 
886 	pr_info("Machine model: %s\n", of_flat_dt_get_machine_name());
887 
888 	return best_data;
889 }
890 
__early_init_dt_declare_initrd(unsigned long start,unsigned long end)891 static void __early_init_dt_declare_initrd(unsigned long start,
892 					   unsigned long end)
893 {
894 	/* ARM64 would cause a BUG to occur here when CONFIG_DEBUG_VM is
895 	 * enabled since __va() is called too early. ARM64 does make use
896 	 * of phys_initrd_start/phys_initrd_size so we can skip this
897 	 * conversion.
898 	 */
899 	if (!IS_ENABLED(CONFIG_ARM64)) {
900 		initrd_start = (unsigned long)__va(start);
901 		initrd_end = (unsigned long)__va(end);
902 		initrd_below_start_ok = 1;
903 	}
904 }
905 
906 /**
907  * early_init_dt_check_for_initrd - Decode initrd location from flat tree
908  * @node: reference to node containing initrd location ('chosen')
909  */
early_init_dt_check_for_initrd(unsigned long node)910 static void __init early_init_dt_check_for_initrd(unsigned long node)
911 {
912 	u64 start, end;
913 	int len;
914 	const __be32 *prop;
915 
916 	if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD))
917 		return;
918 
919 	pr_debug("Looking for initrd properties... ");
920 
921 	prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);
922 	if (!prop)
923 		return;
924 	start = of_read_number(prop, len/4);
925 
926 	prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
927 	if (!prop)
928 		return;
929 	end = of_read_number(prop, len/4);
930 	if (start > end)
931 		return;
932 
933 	__early_init_dt_declare_initrd(start, end);
934 	phys_initrd_start = start;
935 	phys_initrd_size = end - start;
936 
937 	pr_debug("initrd_start=0x%llx  initrd_end=0x%llx\n", start, end);
938 }
939 
940 /**
941  * early_init_dt_check_for_elfcorehdr - Decode elfcorehdr location from flat
942  * tree
943  * @node: reference to node containing elfcorehdr location ('chosen')
944  */
early_init_dt_check_for_elfcorehdr(unsigned long node)945 static void __init early_init_dt_check_for_elfcorehdr(unsigned long node)
946 {
947 	const __be32 *prop;
948 	int len;
949 
950 	if (!IS_ENABLED(CONFIG_CRASH_DUMP))
951 		return;
952 
953 	pr_debug("Looking for elfcorehdr property... ");
954 
955 	prop = of_get_flat_dt_prop(node, "linux,elfcorehdr", &len);
956 	if (!prop || (len < (dt_root_addr_cells + dt_root_size_cells)))
957 		return;
958 
959 	elfcorehdr_addr = dt_mem_next_cell(dt_root_addr_cells, &prop);
960 	elfcorehdr_size = dt_mem_next_cell(dt_root_size_cells, &prop);
961 
962 	pr_debug("elfcorehdr_start=0x%llx elfcorehdr_size=0x%llx\n",
963 		 elfcorehdr_addr, elfcorehdr_size);
964 }
965 
966 static unsigned long chosen_node_offset = -FDT_ERR_NOTFOUND;
967 
968 /*
969  * The main usage of linux,usable-memory-range is for crash dump kernel.
970  * Originally, the number of usable-memory regions is one. Now there may
971  * be two regions, low region and high region.
972  * To make compatibility with existing user-space and older kdump, the low
973  * region is always the last range of linux,usable-memory-range if exist.
974  */
975 #define MAX_USABLE_RANGES		2
976 
977 /**
978  * early_init_dt_check_for_usable_mem_range - Decode usable memory range
979  * location from flat tree
980  */
early_init_dt_check_for_usable_mem_range(void)981 void __init early_init_dt_check_for_usable_mem_range(void)
982 {
983 	struct memblock_region rgn[MAX_USABLE_RANGES] = {0};
984 	const __be32 *prop, *endp;
985 	int len, i;
986 	unsigned long node = chosen_node_offset;
987 
988 	if ((long)node < 0)
989 		return;
990 
991 	pr_debug("Looking for usable-memory-range property... ");
992 
993 	prop = of_get_flat_dt_prop(node, "linux,usable-memory-range", &len);
994 	if (!prop || (len % (dt_root_addr_cells + dt_root_size_cells)))
995 		return;
996 
997 	endp = prop + (len / sizeof(__be32));
998 	for (i = 0; i < MAX_USABLE_RANGES && prop < endp; i++) {
999 		rgn[i].base = dt_mem_next_cell(dt_root_addr_cells, &prop);
1000 		rgn[i].size = dt_mem_next_cell(dt_root_size_cells, &prop);
1001 
1002 		pr_debug("cap_mem_regions[%d]: base=%pa, size=%pa\n",
1003 			 i, &rgn[i].base, &rgn[i].size);
1004 	}
1005 
1006 	memblock_cap_memory_range(rgn[0].base, rgn[0].size);
1007 	for (i = 1; i < MAX_USABLE_RANGES && rgn[i].size; i++)
1008 		memblock_add(rgn[i].base, rgn[i].size);
1009 }
1010 
1011 #ifdef CONFIG_SERIAL_EARLYCON
1012 
early_init_dt_scan_chosen_stdout(void)1013 int __init early_init_dt_scan_chosen_stdout(void)
1014 {
1015 	int offset;
1016 	const char *p, *q, *options = NULL;
1017 	int l;
1018 	const struct earlycon_id *match;
1019 	const void *fdt = initial_boot_params;
1020 	int ret;
1021 
1022 	offset = fdt_path_offset(fdt, "/chosen");
1023 	if (offset < 0)
1024 		offset = fdt_path_offset(fdt, "/chosen@0");
1025 	if (offset < 0)
1026 		return -ENOENT;
1027 
1028 	p = fdt_getprop(fdt, offset, "stdout-path", &l);
1029 	if (!p)
1030 		p = fdt_getprop(fdt, offset, "linux,stdout-path", &l);
1031 	if (!p || !l)
1032 		return -ENOENT;
1033 
1034 	q = strchrnul(p, ':');
1035 	if (*q != '\0')
1036 		options = q + 1;
1037 	l = q - p;
1038 
1039 	/* Get the node specified by stdout-path */
1040 	offset = fdt_path_offset_namelen(fdt, p, l);
1041 	if (offset < 0) {
1042 		pr_warn("earlycon: stdout-path %.*s not found\n", l, p);
1043 		return 0;
1044 	}
1045 
1046 	for (match = __earlycon_table; match < __earlycon_table_end; match++) {
1047 		if (!match->compatible[0])
1048 			continue;
1049 
1050 		if (fdt_node_check_compatible(fdt, offset, match->compatible))
1051 			continue;
1052 
1053 		ret = of_setup_earlycon(match, offset, options);
1054 		if (!ret || ret == -EALREADY)
1055 			return 0;
1056 	}
1057 	return -ENODEV;
1058 }
1059 #endif
1060 
1061 /*
1062  * early_init_dt_scan_root - fetch the top level address and size cells
1063  */
early_init_dt_scan_root(void)1064 int __init early_init_dt_scan_root(void)
1065 {
1066 	const __be32 *prop;
1067 	const void *fdt = initial_boot_params;
1068 	int node = fdt_path_offset(fdt, "/");
1069 
1070 	if (node < 0)
1071 		return -ENODEV;
1072 
1073 	dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
1074 	dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
1075 
1076 	prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
1077 	if (prop)
1078 		dt_root_size_cells = be32_to_cpup(prop);
1079 	pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells);
1080 
1081 	prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
1082 	if (prop)
1083 		dt_root_addr_cells = be32_to_cpup(prop);
1084 	pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells);
1085 
1086 	return 0;
1087 }
1088 
dt_mem_next_cell(int s,const __be32 ** cellp)1089 u64 __init dt_mem_next_cell(int s, const __be32 **cellp)
1090 {
1091 	const __be32 *p = *cellp;
1092 
1093 	*cellp = p + s;
1094 	return of_read_number(p, s);
1095 }
1096 
1097 /*
1098  * early_init_dt_scan_memory - Look for and parse memory nodes
1099  */
early_init_dt_scan_memory(void)1100 int __init early_init_dt_scan_memory(void)
1101 {
1102 	int node, found_memory = 0;
1103 	const void *fdt = initial_boot_params;
1104 
1105 	fdt_for_each_subnode(node, fdt, 0) {
1106 		const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
1107 		const __be32 *reg, *endp;
1108 		int l;
1109 		bool hotpluggable;
1110 
1111 		/* We are scanning "memory" nodes only */
1112 		if (type == NULL || strcmp(type, "memory") != 0)
1113 			continue;
1114 
1115 		if (!of_fdt_device_is_available(fdt, node))
1116 			continue;
1117 
1118 		reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
1119 		if (reg == NULL)
1120 			reg = of_get_flat_dt_prop(node, "reg", &l);
1121 		if (reg == NULL)
1122 			continue;
1123 
1124 		endp = reg + (l / sizeof(__be32));
1125 		hotpluggable = of_get_flat_dt_prop(node, "hotpluggable", NULL);
1126 
1127 		pr_debug("memory scan node %s, reg size %d,\n",
1128 			 fdt_get_name(fdt, node, NULL), l);
1129 
1130 		while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
1131 			u64 base, size;
1132 
1133 			base = dt_mem_next_cell(dt_root_addr_cells, &reg);
1134 			size = dt_mem_next_cell(dt_root_size_cells, &reg);
1135 
1136 			if (size == 0)
1137 				continue;
1138 			pr_debug(" - %llx, %llx\n", base, size);
1139 
1140 			early_init_dt_add_memory_arch(base, size);
1141 
1142 			found_memory = 1;
1143 
1144 			if (!hotpluggable)
1145 				continue;
1146 
1147 			if (memblock_mark_hotplug(base, size))
1148 				pr_warn("failed to mark hotplug range 0x%llx - 0x%llx\n",
1149 					base, base + size);
1150 		}
1151 	}
1152 	return found_memory;
1153 }
1154 
early_init_dt_scan_chosen(char * cmdline)1155 int __init early_init_dt_scan_chosen(char *cmdline)
1156 {
1157 	int l, node;
1158 	const char *p;
1159 	const void *rng_seed;
1160 	const void *fdt = initial_boot_params;
1161 
1162 	node = fdt_path_offset(fdt, "/chosen");
1163 	if (node < 0)
1164 		node = fdt_path_offset(fdt, "/chosen@0");
1165 	if (node < 0)
1166 		/* Handle the cmdline config options even if no /chosen node */
1167 		goto handle_cmdline;
1168 
1169 	chosen_node_offset = node;
1170 
1171 	early_init_dt_check_for_initrd(node);
1172 	early_init_dt_check_for_elfcorehdr(node);
1173 
1174 	rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l);
1175 	if (rng_seed && l > 0) {
1176 		add_bootloader_randomness(rng_seed, l);
1177 
1178 		/* try to clear seed so it won't be found. */
1179 		fdt_nop_property(initial_boot_params, node, "rng-seed");
1180 
1181 		/* update CRC check value */
1182 		of_fdt_crc32 = crc32_be(~0, initial_boot_params,
1183 				fdt_totalsize(initial_boot_params));
1184 	}
1185 
1186 	/* Retrieve command line */
1187 	p = of_get_flat_dt_prop(node, "bootargs", &l);
1188 	if (p != NULL && l > 0)
1189 		strscpy(cmdline, p, min(l, COMMAND_LINE_SIZE));
1190 
1191 handle_cmdline:
1192 	/*
1193 	 * CONFIG_CMDLINE is meant to be a default in case nothing else
1194 	 * managed to set the command line, unless CONFIG_CMDLINE_FORCE
1195 	 * is set in which case we override whatever was found earlier.
1196 	 */
1197 #ifdef CONFIG_CMDLINE
1198 #if defined(CONFIG_CMDLINE_EXTEND)
1199 	strlcat(cmdline, " ", COMMAND_LINE_SIZE);
1200 	strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1201 #elif defined(CONFIG_CMDLINE_FORCE)
1202 	strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1203 #else
1204 	/* No arguments from boot loader, use kernel's  cmdl*/
1205 	if (!((char *)cmdline)[0])
1206 		strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1207 #endif
1208 #endif /* CONFIG_CMDLINE */
1209 
1210 	pr_debug("Command line is: %s\n", (char *)cmdline);
1211 
1212 	return 0;
1213 }
1214 
1215 #ifndef MIN_MEMBLOCK_ADDR
1216 #define MIN_MEMBLOCK_ADDR	__pa(PAGE_OFFSET)
1217 #endif
1218 #ifndef MAX_MEMBLOCK_ADDR
1219 #define MAX_MEMBLOCK_ADDR	((phys_addr_t)~0)
1220 #endif
1221 
early_init_dt_add_memory_arch(u64 base,u64 size)1222 void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
1223 {
1224 	const u64 phys_offset = MIN_MEMBLOCK_ADDR;
1225 
1226 	if (size < PAGE_SIZE - (base & ~PAGE_MASK)) {
1227 		pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
1228 			base, base + size);
1229 		return;
1230 	}
1231 
1232 	if (!PAGE_ALIGNED(base)) {
1233 		size -= PAGE_SIZE - (base & ~PAGE_MASK);
1234 		base = PAGE_ALIGN(base);
1235 	}
1236 	size &= PAGE_MASK;
1237 
1238 	if (base > MAX_MEMBLOCK_ADDR) {
1239 		pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
1240 			base, base + size);
1241 		return;
1242 	}
1243 
1244 	if (base + size - 1 > MAX_MEMBLOCK_ADDR) {
1245 		pr_warn("Ignoring memory range 0x%llx - 0x%llx\n",
1246 			((u64)MAX_MEMBLOCK_ADDR) + 1, base + size);
1247 		size = MAX_MEMBLOCK_ADDR - base + 1;
1248 	}
1249 
1250 	if (base + size < phys_offset) {
1251 		pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
1252 			base, base + size);
1253 		return;
1254 	}
1255 	if (base < phys_offset) {
1256 		pr_warn("Ignoring memory range 0x%llx - 0x%llx\n",
1257 			base, phys_offset);
1258 		size -= phys_offset - base;
1259 		base = phys_offset;
1260 	}
1261 	memblock_add(base, size);
1262 }
1263 
early_init_dt_alloc_memory_arch(u64 size,u64 align)1264 static void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
1265 {
1266 	void *ptr = memblock_alloc(size, align);
1267 
1268 	if (!ptr)
1269 		panic("%s: Failed to allocate %llu bytes align=0x%llx\n",
1270 		      __func__, size, align);
1271 
1272 	return ptr;
1273 }
1274 
early_init_dt_verify(void * params)1275 bool __init early_init_dt_verify(void *params)
1276 {
1277 	if (!params)
1278 		return false;
1279 
1280 	/* check device tree validity */
1281 	if (fdt_check_header(params))
1282 		return false;
1283 
1284 	/* Setup flat device-tree pointer */
1285 	initial_boot_params = params;
1286 	of_fdt_crc32 = crc32_be(~0, initial_boot_params,
1287 				fdt_totalsize(initial_boot_params));
1288 	return true;
1289 }
1290 
1291 
early_init_dt_scan_nodes(void)1292 void __init early_init_dt_scan_nodes(void)
1293 {
1294 	int rc;
1295 
1296 	/* Initialize {size,address}-cells info */
1297 	early_init_dt_scan_root();
1298 
1299 	/* Retrieve various information from the /chosen node */
1300 	rc = early_init_dt_scan_chosen(boot_command_line);
1301 	if (rc)
1302 		pr_warn("No chosen node found, continuing without\n");
1303 
1304 	/* Setup memory, calling early_init_dt_add_memory_arch */
1305 	early_init_dt_scan_memory();
1306 
1307 	/* Handle linux,usable-memory-range property */
1308 	early_init_dt_check_for_usable_mem_range();
1309 }
1310 
early_init_dt_scan(void * params)1311 bool __init early_init_dt_scan(void *params)
1312 {
1313 	bool status;
1314 
1315 	status = early_init_dt_verify(params);
1316 	if (!status)
1317 		return false;
1318 
1319 	early_init_dt_scan_nodes();
1320 	return true;
1321 }
1322 
1323 /**
1324  * unflatten_device_tree - create tree of device_nodes from flat blob
1325  *
1326  * unflattens the device-tree passed by the firmware, creating the
1327  * tree of struct device_node. It also fills the "name" and "type"
1328  * pointers of the nodes so the normal device-tree walking functions
1329  * can be used.
1330  */
unflatten_device_tree(void)1331 void __init unflatten_device_tree(void)
1332 {
1333 	__unflatten_device_tree(initial_boot_params, NULL, &of_root,
1334 				early_init_dt_alloc_memory_arch, false);
1335 
1336 	/* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */
1337 	of_alias_scan(early_init_dt_alloc_memory_arch);
1338 
1339 	unittest_unflatten_overlay_base();
1340 }
1341 
1342 /**
1343  * unflatten_and_copy_device_tree - copy and create tree of device_nodes from flat blob
1344  *
1345  * Copies and unflattens the device-tree passed by the firmware, creating the
1346  * tree of struct device_node. It also fills the "name" and "type"
1347  * pointers of the nodes so the normal device-tree walking functions
1348  * can be used. This should only be used when the FDT memory has not been
1349  * reserved such is the case when the FDT is built-in to the kernel init
1350  * section. If the FDT memory is reserved already then unflatten_device_tree
1351  * should be used instead.
1352  */
unflatten_and_copy_device_tree(void)1353 void __init unflatten_and_copy_device_tree(void)
1354 {
1355 	int size;
1356 	void *dt;
1357 
1358 	if (!initial_boot_params) {
1359 		pr_warn("No valid device tree found, continuing without\n");
1360 		return;
1361 	}
1362 
1363 	size = fdt_totalsize(initial_boot_params);
1364 	dt = early_init_dt_alloc_memory_arch(size,
1365 					     roundup_pow_of_two(FDT_V17_SIZE));
1366 
1367 	if (dt) {
1368 		memcpy(dt, initial_boot_params, size);
1369 		initial_boot_params = dt;
1370 	}
1371 	unflatten_device_tree();
1372 }
1373 
1374 #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)1375 static ssize_t of_fdt_raw_read(struct file *filp, struct kobject *kobj,
1376 			       struct bin_attribute *bin_attr,
1377 			       char *buf, loff_t off, size_t count)
1378 {
1379 	memcpy(buf, initial_boot_params + off, count);
1380 	return count;
1381 }
1382 
of_fdt_raw_init(void)1383 static int __init of_fdt_raw_init(void)
1384 {
1385 	static struct bin_attribute of_fdt_raw_attr =
1386 		__BIN_ATTR(fdt, S_IRUSR, of_fdt_raw_read, NULL, 0);
1387 
1388 	if (!initial_boot_params)
1389 		return 0;
1390 
1391 	if (of_fdt_crc32 != crc32_be(~0, initial_boot_params,
1392 				     fdt_totalsize(initial_boot_params))) {
1393 		pr_warn("not creating '/sys/firmware/fdt': CRC check failed\n");
1394 		return 0;
1395 	}
1396 	of_fdt_raw_attr.size = fdt_totalsize(initial_boot_params);
1397 	return sysfs_create_bin_file(firmware_kobj, &of_fdt_raw_attr);
1398 }
1399 late_initcall(of_fdt_raw_init);
1400 #endif
1401 
1402 #endif /* CONFIG_OF_EARLY_FLATTREE */
1403