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