fdt.c

   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/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#include <linux/kexec_handover.h>
  29
  30#include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
  31#include <asm/page.h>
  32
  33#include "of_private.h"
  34
  35/*
  36 * __dtb_empty_root_begin[] and __dtb_empty_root_end[] magically created by
  37 * cmd_wrap_S_dtb in scripts/Makefile.dtbs
  38 */
  39extern uint8_t __dtb_empty_root_begin[];
  40extern uint8_t __dtb_empty_root_end[];
  41
  42/*
  43 * of_fdt_limit_memory - limit the number of regions in the /memory node
  44 * @limit: maximum entries
  45 *
  46 * Adjust the flattened device tree to have at most 'limit' number of
  47 * memory entries in the /memory node. This function may be called
  48 * any time after initial_boot_param is set.
  49 */
  50void __init of_fdt_limit_memory(int limit)
  51{
  52	int memory;
  53	int len;
  54	const void *val;
  55	int cell_size = sizeof(uint32_t)*(dt_root_addr_cells + dt_root_size_cells);
  56
  57	memory = fdt_path_offset(initial_boot_params, "/memory");
  58	if (memory > 0) {
  59		val = fdt_getprop(initial_boot_params, memory, "reg", &len);
  60		if (len > limit*cell_size) {
  61			len = limit*cell_size;
  62			pr_debug("Limiting number of entries to %d\n", limit);
  63			fdt_setprop(initial_boot_params, memory, "reg", val,
  64					len);
  65		}
  66	}
  67}
  68
  69bool of_fdt_device_is_available(const void *blob, unsigned long node)
  70{
  71	const char *status = fdt_getprop(blob, node, "status", NULL);
  72
  73	if (!status)
  74		return true;
  75
  76	if (!strcmp(status, "ok") || !strcmp(status, "okay"))
  77		return true;
  78
  79	return false;
  80}
  81
  82static void *unflatten_dt_alloc(void **mem, unsigned long size,
  83				       unsigned long align)
  84{
  85	void *res;
  86
  87	*mem = PTR_ALIGN(*mem, align);
  88	res = *mem;
  89	*mem += size;
  90
  91	return res;
  92}
  93
  94static void populate_properties(const void *blob,
  95				int offset,
  96				void **mem,
  97				struct device_node *np,
  98				const char *nodename,
  99				bool dryrun)
 100{
 101	struct property *pp, **pprev = NULL;
 102	int cur;
 103	bool has_name = false;
 104
 105	pprev = &np->properties;
 106	for (cur = fdt_first_property_offset(blob, offset);
 107	     cur >= 0;
 108	     cur = fdt_next_property_offset(blob, cur)) {
 109		const __be32 *val;
 110		const char *pname;
 111		u32 sz;
 112
 113		val = fdt_getprop_by_offset(blob, cur, &pname, &sz);
 114		if (!val) {
 115			pr_warn("Cannot locate property at 0x%x\n", cur);
 116			continue;
 117		}
 118
 119		if (!pname) {
 120			pr_warn("Cannot find property name at 0x%x\n", cur);
 121			continue;
 122		}
 123
 124		if (!strcmp(pname, "name"))
 125			has_name = true;
 126
 127		pp = unflatten_dt_alloc(mem, sizeof(struct property),
 128					__alignof__(struct property));
 129		if (dryrun)
 130			continue;
 131
 132		/* We accept flattened tree phandles either in
 133		 * ePAPR-style "phandle" properties, or the
 134		 * legacy "linux,phandle" properties.  If both
 135		 * appear and have different values, things
 136		 * will get weird. Don't do that.
 137		 */
 138		if (!strcmp(pname, "phandle") ||
 139		    !strcmp(pname, "linux,phandle")) {
 140			if (!np->phandle)
 141				np->phandle = be32_to_cpup(val);
 142		}
 143
 144		/* And we process the "ibm,phandle" property
 145		 * used in pSeries dynamic device tree
 146		 * stuff
 147		 */
 148		if (!strcmp(pname, "ibm,phandle"))
 149			np->phandle = be32_to_cpup(val);
 150
 151		pp->name   = (char *)pname;
 152		pp->length = sz;
 153		pp->value  = (__be32 *)val;
 154		*pprev     = pp;
 155		pprev      = &pp->next;
 156	}
 157
 158	/* With version 0x10 we may not have the name property,
 159	 * recreate it here from the unit name if absent
 160	 */
 161	if (!has_name) {
 162		const char *p = nodename, *ps = p, *pa = NULL;
 163		int len;
 164
 165		while (*p) {
 166			if ((*p) == '@')
 167				pa = p;
 168			else if ((*p) == '/')
 169				ps = p + 1;
 170			p++;
 171		}
 172
 173		if (pa < ps)
 174			pa = p;
 175		len = (pa - ps) + 1;
 176		pp = unflatten_dt_alloc(mem, sizeof(struct property) + len,
 177					__alignof__(struct property));
 178		if (!dryrun) {
 179			pp->name   = "name";
 180			pp->length = len;
 181			pp->value  = pp + 1;
 182			*pprev     = pp;
 183			memcpy(pp->value, ps, len - 1);
 184			((char *)pp->value)[len - 1] = 0;
 185			pr_debug("fixed up name for %s -> %s\n",
 186				 nodename, (char *)pp->value);
 187		}
 188	}
 189}
 190
 191static int populate_node(const void *blob,
 192			  int offset,
 193			  void **mem,
 194			  struct device_node *dad,
 195			  struct device_node **pnp,
 196			  bool dryrun)
 197{
 198	struct device_node *np;
 199	const char *pathp;
 200	int len;
 201
 202	pathp = fdt_get_name(blob, offset, &len);
 203	if (!pathp) {
 204		*pnp = NULL;
 205		return len;
 206	}
 207
 208	len++;
 209
 210	np = unflatten_dt_alloc(mem, sizeof(struct device_node) + len,
 211				__alignof__(struct device_node));
 212	if (!dryrun) {
 213		char *fn;
 214		of_node_init(np);
 215		np->full_name = fn = ((char *)np) + sizeof(*np);
 216
 217		memcpy(fn, pathp, len);
 218
 219		if (dad != NULL) {
 220			np->parent = dad;
 221			np->sibling = dad->child;
 222			dad->child = np;
 223		}
 224	}
 225
 226	populate_properties(blob, offset, mem, np, pathp, dryrun);
 227	if (!dryrun) {
 228		np->name = of_get_property(np, "name", NULL);
 229		if (!np->name)
 230			np->name = "<NULL>";
 231	}
 232
 233	*pnp = np;
 234	return 0;
 235}
 236
 237static void reverse_nodes(struct device_node *parent)
 238{
 239	struct device_node *child, *next;
 240
 241	/* In-depth first */
 242	child = parent->child;
 243	while (child) {
 244		reverse_nodes(child);
 245
 246		child = child->sibling;
 247	}
 248
 249	/* Reverse the nodes in the child list */
 250	child = parent->child;
 251	parent->child = NULL;
 252	while (child) {
 253		next = child->sibling;
 254
 255		child->sibling = parent->child;
 256		parent->child = child;
 257		child = next;
 258	}
 259}
 260
 261/**
 262 * unflatten_dt_nodes - Alloc and populate a device_node from the flat tree
 263 * @blob: The parent device tree blob
 264 * @mem: Memory chunk to use for allocating device nodes and properties
 265 * @dad: Parent struct device_node
 266 * @nodepp: The device_node tree created by the call
 267 *
 268 * Return: The size of unflattened device tree or error code
 269 */
 270static int unflatten_dt_nodes(const void *blob,
 271			      void *mem,
 272			      struct device_node *dad,
 273			      struct device_node **nodepp)
 274{
 275	struct device_node *root;
 276	int offset = 0, depth = 0, initial_depth = 0;
 277#define FDT_MAX_DEPTH	64
 278	struct device_node *nps[FDT_MAX_DEPTH];
 279	void *base = mem;
 280	bool dryrun = !base;
 281	int ret;
 282
 283	if (nodepp)
 284		*nodepp = NULL;
 285
 286	/*
 287	 * We're unflattening device sub-tree if @dad is valid. There are
 288	 * possibly multiple nodes in the first level of depth. We need
 289	 * set @depth to 1 to make fdt_next_node() happy as it bails
 290	 * immediately when negative @depth is found. Otherwise, the device
 291	 * nodes except the first one won't be unflattened successfully.
 292	 */
 293	if (dad)
 294		depth = initial_depth = 1;
 295
 296	root = dad;
 297	nps[depth] = dad;
 298
 299	for (offset = 0;
 300	     offset >= 0 && depth >= initial_depth;
 301	     offset = fdt_next_node(blob, offset, &depth)) {
 302		if (WARN_ON_ONCE(depth >= FDT_MAX_DEPTH - 1))
 303			continue;
 304
 305		if (!IS_ENABLED(CONFIG_OF_KOBJ) &&
 306		    !of_fdt_device_is_available(blob, offset))
 307			continue;
 308
 309		ret = populate_node(blob, offset, &mem, nps[depth],
 310				   &nps[depth+1], dryrun);
 311		if (ret < 0)
 312			return ret;
 313
 314		if (!dryrun && nodepp && !*nodepp)
 315			*nodepp = nps[depth+1];
 316		if (!dryrun && !root)
 317			root = nps[depth+1];
 318	}
 319
 320	if (offset < 0 && offset != -FDT_ERR_NOTFOUND) {
 321		pr_err("Error %d processing FDT\n", offset);
 322		return -EINVAL;
 323	}
 324
 325	/*
 326	 * Reverse the child list. Some drivers assumes node order matches .dts
 327	 * node order
 328	 */
 329	if (!dryrun)
 330		reverse_nodes(root);
 331
 332	return mem - base;
 333}
 334
 335/**
 336 * __unflatten_device_tree - create tree of device_nodes from flat blob
 337 * @blob: The blob to expand
 338 * @dad: Parent device node
 339 * @mynodes: The device_node tree created by the call
 340 * @dt_alloc: An allocator that provides a virtual address to memory
 341 * for the resulting tree
 342 * @detached: if true set OF_DETACHED on @mynodes
 343 *
 344 * unflattens a device-tree, creating the tree of struct device_node. It also
 345 * fills the "name" and "type" pointers of the nodes so the normal device-tree
 346 * walking functions can be used.
 347 *
 348 * Return: NULL on failure or the memory chunk containing the unflattened
 349 * device tree on success.
 350 */
 351void *__unflatten_device_tree(const void *blob,
 352			      struct device_node *dad,
 353			      struct device_node **mynodes,
 354			      void *(*dt_alloc)(u64 size, u64 align),
 355			      bool detached)
 356{
 357	int size;
 358	void *mem;
 359	int ret;
 360
 361	if (mynodes)
 362		*mynodes = NULL;
 363
 364	pr_debug(" -> unflatten_device_tree()\n");
 365
 366	if (!blob) {
 367		pr_debug("No device tree pointer\n");
 368		return NULL;
 369	}
 370
 371	pr_debug("Unflattening device tree:\n");
 372	pr_debug("magic: %08x\n", fdt_magic(blob));
 373	pr_debug("size: %08x\n", fdt_totalsize(blob));
 374	pr_debug("version: %08x\n", fdt_version(blob));
 375
 376	if (fdt_check_header(blob)) {
 377		pr_err("Invalid device tree blob header\n");
 378		return NULL;
 379	}
 380
 381	/* First pass, scan for size */
 382	size = unflatten_dt_nodes(blob, NULL, dad, NULL);
 383	if (size <= 0)
 384		return NULL;
 385
 386	size = ALIGN(size, 4);
 387	pr_debug("  size is %d, allocating...\n", size);
 388
 389	/* Allocate memory for the expanded device tree */
 390	mem = dt_alloc(size + 4, __alignof__(struct device_node));
 391	if (!mem)
 392		return NULL;
 393
 394	memset(mem, 0, size);
 395
 396	*(__be32 *)(mem + size) = cpu_to_be32(0xdeadbeef);
 397
 398	pr_debug("  unflattening %p...\n", mem);
 399
 400	/* Second pass, do actual unflattening */
 401	ret = unflatten_dt_nodes(blob, mem, dad, mynodes);
 402
 403	if (be32_to_cpup(mem + size) != 0xdeadbeef)
 404		pr_warn("End of tree marker overwritten: %08x\n",
 405			be32_to_cpup(mem + size));
 406
 407	if (ret <= 0)
 408		return NULL;
 409
 410	if (detached && mynodes && *mynodes) {
 411		of_node_set_flag(*mynodes, OF_DETACHED);
 412		pr_debug("unflattened tree is detached\n");
 413	}
 414
 415	pr_debug(" <- unflatten_device_tree()\n");
 416	return mem;
 417}
 418
 419static void *kernel_tree_alloc(u64 size, u64 align)
 420{
 421	return kzalloc(size, GFP_KERNEL);
 422}
 423
 424static DEFINE_MUTEX(of_fdt_unflatten_mutex);
 425
 426/**
 427 * of_fdt_unflatten_tree - create tree of device_nodes from flat blob
 428 * @blob: Flat device tree blob
 429 * @dad: Parent device node
 430 * @mynodes: The device tree created by the call
 431 *
 432 * unflattens the device-tree passed by the firmware, creating the
 433 * tree of struct device_node. It also fills the "name" and "type"
 434 * pointers of the nodes so the normal device-tree walking functions
 435 * can be used.
 436 *
 437 * Return: NULL on failure or the memory chunk containing the unflattened
 438 * device tree on success.
 439 */
 440void *of_fdt_unflatten_tree(const unsigned long *blob,
 441			    struct device_node *dad,
 442			    struct device_node **mynodes)
 443{
 444	void *mem;
 445
 446	mutex_lock(&of_fdt_unflatten_mutex);
 447	mem = __unflatten_device_tree(blob, dad, mynodes, &kernel_tree_alloc,
 448				      true);
 449	mutex_unlock(&of_fdt_unflatten_mutex);
 450
 451	return mem;
 452}
 453EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree);
 454
 455/* Everything below here references initial_boot_params directly. */
 456int __initdata dt_root_addr_cells;
 457int __initdata dt_root_size_cells;
 458
 459void *initial_boot_params __ro_after_init;
 460phys_addr_t initial_boot_params_pa __ro_after_init;
 461
 462#ifdef CONFIG_OF_EARLY_FLATTREE
 463
 464static u32 of_fdt_crc32;
 465
 466/*
 467 * fdt_reserve_elfcorehdr() - reserves memory for elf core header
 468 *
 469 * This function reserves the memory occupied by an elf core header
 470 * described in the device tree. This region contains all the
 471 * information about primary kernel's core image and is used by a dump
 472 * capture kernel to access the system memory on primary kernel.
 473 */
 474static void __init fdt_reserve_elfcorehdr(void)
 475{
 476	if (!IS_ENABLED(CONFIG_CRASH_DUMP) || !elfcorehdr_size)
 477		return;
 478
 479	if (memblock_is_region_reserved(elfcorehdr_addr, elfcorehdr_size)) {
 480		pr_warn("elfcorehdr is overlapped\n");
 481		return;
 482	}
 483
 484	memblock_reserve(elfcorehdr_addr, elfcorehdr_size);
 485
 486	pr_info("Reserving %llu KiB of memory at 0x%llx for elfcorehdr\n",
 487		elfcorehdr_size >> 10, elfcorehdr_addr);
 488}
 489
 490/**
 491 * early_init_fdt_scan_reserved_mem() - create reserved memory regions
 492 *
 493 * This function grabs memory from early allocator for device exclusive use
 494 * defined in device tree structures. It should be called by arch specific code
 495 * once the early allocator (i.e. memblock) has been fully activated.
 496 */
 497void __init early_init_fdt_scan_reserved_mem(void)
 498{
 499	int n;
 500	int res;
 501	u64 base, size;
 502
 503	if (!initial_boot_params)
 504		return;
 505
 506	fdt_reserve_elfcorehdr();
 507	fdt_scan_reserved_mem();
 508
 509	/* Process header /memreserve/ fields */
 510	for (n = 0; ; n++) {
 511		res = fdt_get_mem_rsv(initial_boot_params, n, &base, &size);
 512		if (res) {
 513			pr_err("Invalid memory reservation block index %d\n", n);
 514			break;
 515		}
 516		if (!size)
 517			break;
 518		memblock_reserve(base, size);
 519	}
 520}
 521
 522/**
 523 * early_init_fdt_reserve_self() - reserve the memory used by the FDT blob
 524 */
 525void __init early_init_fdt_reserve_self(void)
 526{
 527	if (!initial_boot_params)
 528		return;
 529
 530	/* Reserve the dtb region */
 531	memblock_reserve(__pa(initial_boot_params),
 532			 fdt_totalsize(initial_boot_params));
 533}
 534
 535/**
 536 * of_scan_flat_dt - scan flattened tree blob and call callback on each.
 537 * @it: callback function
 538 * @data: context data pointer
 539 *
 540 * This function is used to scan the flattened device-tree, it is
 541 * used to extract the memory information at boot before we can
 542 * unflatten the tree
 543 */
 544int __init of_scan_flat_dt(int (*it)(unsigned long node,
 545				     const char *uname, int depth,
 546				     void *data),
 547			   void *data)
 548{
 549	const void *blob = initial_boot_params;
 550	const char *pathp;
 551	int offset, rc = 0, depth = -1;
 552
 553	if (!blob)
 554		return 0;
 555
 556	for (offset = fdt_next_node(blob, -1, &depth);
 557	     offset >= 0 && depth >= 0 && !rc;
 558	     offset = fdt_next_node(blob, offset, &depth)) {
 559
 560		pathp = fdt_get_name(blob, offset, NULL);
 561		rc = it(offset, pathp, depth, data);
 562	}
 563	return rc;
 564}
 565
 566/**
 567 * of_scan_flat_dt_subnodes - scan sub-nodes of a node call callback on each.
 568 * @parent: parent node
 569 * @it: callback function
 570 * @data: context data pointer
 571 *
 572 * This function is used to scan sub-nodes of a node.
 573 */
 574int __init of_scan_flat_dt_subnodes(unsigned long parent,
 575				    int (*it)(unsigned long node,
 576					      const char *uname,
 577					      void *data),
 578				    void *data)
 579{
 580	const void *blob = initial_boot_params;
 581	int node;
 582
 583	fdt_for_each_subnode(node, blob, parent) {
 584		const char *pathp;
 585		int rc;
 586
 587		pathp = fdt_get_name(blob, node, NULL);
 588		rc = it(node, pathp, data);
 589		if (rc)
 590			return rc;
 591	}
 592	return 0;
 593}
 594
 595/**
 596 * of_get_flat_dt_subnode_by_name - get the subnode by given name
 597 *
 598 * @node: the parent node
 599 * @uname: the name of subnode
 600 * @return offset of the subnode, or -FDT_ERR_NOTFOUND if there is none
 601 */
 602
 603int __init of_get_flat_dt_subnode_by_name(unsigned long node, const char *uname)
 604{
 605	return fdt_subnode_offset(initial_boot_params, node, uname);
 606}
 607
 608/*
 609 * of_get_flat_dt_root - find the root node in the flat blob
 610 */
 611unsigned long __init of_get_flat_dt_root(void)
 612{
 613	return 0;
 614}
 615
 616/*
 617 * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
 618 *
 619 * This function can be used within scan_flattened_dt callback to get
 620 * access to properties
 621 */
 622const void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
 623				       int *size)
 624{
 625	return fdt_getprop(initial_boot_params, node, name, size);
 626}
 627
 628const __be32 *__init of_flat_dt_get_addr_size_prop(unsigned long node,
 629						   const char *name,
 630						   int *entries)
 631{
 632	const __be32 *prop;
 633	int len, elen = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
 634
 635	prop = of_get_flat_dt_prop(node, name, &len);
 636	if (!prop || len % elen) {
 637		*entries = 0;
 638		return NULL;
 639	}
 640
 641	*entries = len / elen;
 642	return prop;
 643}
 644
 645bool __init of_flat_dt_get_addr_size(unsigned long node, const char *name,
 646				     u64 *addr, u64 *size)
 647{
 648	const __be32 *prop;
 649	int entries;
 650
 651	prop = of_flat_dt_get_addr_size_prop(node, name, &entries);
 652	if (!prop || entries != 1)
 653		return false;
 654
 655	of_flat_dt_read_addr_size(prop, 0, addr, size);
 656	return true;
 657}
 658
 659void __init of_flat_dt_read_addr_size(const __be32 *prop, int entry_index,
 660				      u64 *addr, u64 *size)
 661{
 662	int entry_cells = dt_root_addr_cells + dt_root_size_cells;
 663	prop += entry_cells * entry_index;
 664
 665	*addr = dt_mem_next_cell(dt_root_addr_cells, &prop);
 666	*size = dt_mem_next_cell(dt_root_size_cells, &prop);
 667}
 668
 669/**
 670 * of_fdt_is_compatible - Return true if given node from the given blob has
 671 * compat in its compatible list
 672 * @blob: A device tree blob
 673 * @node: node to test
 674 * @compat: compatible string to compare with compatible list.
 675 *
 676 * Return: a non-zero value on match with smaller values returned for more
 677 * specific compatible values.
 678 */
 679static int of_fdt_is_compatible(const void *blob,
 680		      unsigned long node, const char *compat)
 681{
 682	const char *cp;
 683	int cplen;
 684	unsigned long l, score = 0;
 685
 686	cp = fdt_getprop(blob, node, "compatible", &cplen);
 687	if (cp == NULL)
 688		return 0;
 689	while (cplen > 0) {
 690		score++;
 691		if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
 692			return score;
 693		l = strlen(cp) + 1;
 694		cp += l;
 695		cplen -= l;
 696	}
 697
 698	return 0;
 699}
 700
 701/**
 702 * of_flat_dt_is_compatible - Return true if given node has compat in compatible list
 703 * @node: node to test
 704 * @compat: compatible string to compare with compatible list.
 705 */
 706int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
 707{
 708	return of_fdt_is_compatible(initial_boot_params, node, compat);
 709}
 710
 711/*
 712 * of_flat_dt_match - Return true if node matches a list of compatible values
 713 */
 714static int __init of_flat_dt_match(unsigned long node, const char *const *compat)
 715{
 716	unsigned int tmp, score = 0;
 717
 718	if (!compat)
 719		return 0;
 720
 721	while (*compat) {
 722		tmp = of_fdt_is_compatible(initial_boot_params, node, *compat);
 723		if (tmp && (score == 0 || (tmp < score)))
 724			score = tmp;
 725		compat++;
 726	}
 727
 728	return score;
 729}
 730
 731/*
 732 * of_get_flat_dt_phandle - Given a node in the flat blob, return the phandle
 733 */
 734uint32_t __init of_get_flat_dt_phandle(unsigned long node)
 735{
 736	return fdt_get_phandle(initial_boot_params, node);
 737}
 738
 739const char * __init of_flat_dt_get_machine_name(void)
 740{
 741	const char *name;
 742	unsigned long dt_root = of_get_flat_dt_root();
 743
 744	name = of_get_flat_dt_prop(dt_root, "model", NULL);
 745	if (!name)
 746		name = of_get_flat_dt_prop(dt_root, "compatible", NULL);
 747	return name;
 748}
 749
 750/**
 751 * of_flat_dt_match_machine - Iterate match tables to find matching machine.
 752 *
 753 * @default_match: A machine specific ptr to return in case of no match.
 754 * @get_next_compat: callback function to return next compatible match table.
 755 *
 756 * Iterate through machine match tables to find the best match for the machine
 757 * compatible string in the FDT.
 758 */
 759const void * __init of_flat_dt_match_machine(const void *default_match,
 760		const void * (*get_next_compat)(const char * const**))
 761{
 762	const void *data = NULL;
 763	const void *best_data = default_match;
 764	const char *const *compat;
 765	unsigned long dt_root;
 766	unsigned int best_score = ~1, score = 0;
 767
 768	dt_root = of_get_flat_dt_root();
 769	while ((data = get_next_compat(&compat))) {
 770		score = of_flat_dt_match(dt_root, compat);
 771		if (score > 0 && score < best_score) {
 772			best_data = data;
 773			best_score = score;
 774		}
 775	}
 776	if (!best_data) {
 777		const char *prop;
 778		int size;
 779
 780		pr_err("\n unrecognized device tree list:\n[ ");
 781
 782		prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
 783		if (prop) {
 784			while (size > 0) {
 785				printk("'%s' ", prop);
 786				size -= strlen(prop) + 1;
 787				prop += strlen(prop) + 1;
 788			}
 789		}
 790		printk("]\n\n");
 791		return NULL;
 792	}
 793
 794	pr_info("Machine model: %s\n", of_flat_dt_get_machine_name());
 795
 796	return best_data;
 797}
 798
 799static void __early_init_dt_declare_initrd(unsigned long start,
 800					   unsigned long end)
 801{
 802	/*
 803	 * __va() is not yet available this early on some platforms. In that
 804	 * case, the platform uses phys_initrd_start/phys_initrd_size instead
 805	 * and does the VA conversion itself.
 806	 */
 807	if (!IS_ENABLED(CONFIG_ARM64) &&
 808	    !(IS_ENABLED(CONFIG_RISCV) && IS_ENABLED(CONFIG_64BIT))) {
 809		initrd_start = (unsigned long)__va(start);
 810		initrd_end = (unsigned long)__va(end);
 811		initrd_below_start_ok = 1;
 812	}
 813}
 814
 815/**
 816 * early_init_dt_check_for_initrd - Decode initrd location from flat tree
 817 * @node: reference to node containing initrd location ('chosen')
 818 */
 819static void __init early_init_dt_check_for_initrd(unsigned long node)
 820{
 821	u64 start, end;
 822	int len;
 823	const __be32 *prop;
 824
 825	if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD))
 826		return;
 827
 828	pr_debug("Looking for initrd properties... ");
 829
 830	prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);
 831	if (!prop)
 832		return;
 833	start = of_read_number(prop, len/4);
 834
 835	prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
 836	if (!prop)
 837		return;
 838	end = of_read_number(prop, len/4);
 839	if (start > end)
 840		return;
 841
 842	__early_init_dt_declare_initrd(start, end);
 843	phys_initrd_start = start;
 844	phys_initrd_size = end - start;
 845
 846	pr_debug("initrd_start=0x%llx  initrd_end=0x%llx\n", start, end);
 847}
 848
 849/**
 850 * early_init_dt_check_for_elfcorehdr - Decode elfcorehdr location from flat
 851 * tree
 852 * @node: reference to node containing elfcorehdr location ('chosen')
 853 */
 854static void __init early_init_dt_check_for_elfcorehdr(unsigned long node)
 855{
 856	if (!IS_ENABLED(CONFIG_CRASH_DUMP))
 857		return;
 858
 859	pr_debug("Looking for elfcorehdr property... ");
 860
 861	if (!of_flat_dt_get_addr_size(node, "linux,elfcorehdr",
 862				      &elfcorehdr_addr, &elfcorehdr_size))
 863		return;
 864
 865	pr_debug("elfcorehdr_start=0x%llx elfcorehdr_size=0x%llx\n",
 866		 elfcorehdr_addr, elfcorehdr_size);
 867}
 868
 869static unsigned long chosen_node_offset = -FDT_ERR_NOTFOUND;
 870
 871/*
 872 * The main usage of linux,usable-memory-range is for crash dump kernel.
 873 * Originally, the number of usable-memory regions is one. Now there may
 874 * be two regions, low region and high region.
 875 * To make compatibility with existing user-space and older kdump, the low
 876 * region is always the last range of linux,usable-memory-range if exist.
 877 */
 878#define MAX_USABLE_RANGES		2
 879
 880/**
 881 * early_init_dt_check_for_usable_mem_range - Decode usable memory range
 882 * location from flat tree
 883 */
 884void __init early_init_dt_check_for_usable_mem_range(void)
 885{
 886	struct memblock_region rgn[MAX_USABLE_RANGES] = {0};
 887	const __be32 *prop;
 888	int len, i;
 889	u64 base, size;
 890	unsigned long node = chosen_node_offset;
 891
 892	if ((long)node < 0)
 893		return;
 894
 895	pr_debug("Looking for usable-memory-range property... ");
 896
 897	prop = of_flat_dt_get_addr_size_prop(node, "linux,usable-memory-range",
 898					     &len);
 899	if (!prop)
 900		return;
 901
 902	len = min(len, MAX_USABLE_RANGES);
 903
 904	for (i = 0; i < len; i++) {
 905		of_flat_dt_read_addr_size(prop, i, &base, &size);
 906		rgn[i].base = base;
 907		rgn[i].size = size;
 908
 909		pr_debug("cap_mem_regions[%d]: base=%pa, size=%pa\n",
 910			 i, &rgn[i].base, &rgn[i].size);
 911	}
 912
 913	memblock_cap_memory_range(rgn[0].base, rgn[0].size);
 914	for (i = 1; i < MAX_USABLE_RANGES && rgn[i].size; i++)
 915		memblock_add(rgn[i].base, rgn[i].size);
 916}
 917
 918/**
 919 * early_init_dt_check_kho - Decode info required for kexec handover from DT
 920 */
 921static void __init early_init_dt_check_kho(void)
 922{
 923	unsigned long node = chosen_node_offset;
 924	u64 fdt_start, fdt_size, scratch_start, scratch_size;
 925
 926	if (!IS_ENABLED(CONFIG_KEXEC_HANDOVER) || (long)node < 0)
 927		return;
 928
 929	if (!of_flat_dt_get_addr_size(node, "linux,kho-fdt",
 930				      &fdt_start, &fdt_size))
 931		return;
 932
 933	if (!of_flat_dt_get_addr_size(node, "linux,kho-scratch",
 934				      &scratch_start, &scratch_size))
 935		return;
 936
 937	kho_populate(fdt_start, fdt_size, scratch_start, scratch_size);
 938}
 939
 940#ifdef CONFIG_SERIAL_EARLYCON
 941
 942int __init early_init_dt_scan_chosen_stdout(void)
 943{
 944	int offset;
 945	const char *p, *q, *options = NULL;
 946	int l;
 947	const struct earlycon_id *match;
 948	const void *fdt = initial_boot_params;
 949	int ret;
 950
 951	offset = fdt_path_offset(fdt, "/chosen");
 952	if (offset < 0)
 953		offset = fdt_path_offset(fdt, "/chosen@0");
 954	if (offset < 0)
 955		return -ENOENT;
 956
 957	p = fdt_getprop(fdt, offset, "stdout-path", &l);
 958	if (!p)
 959		p = fdt_getprop(fdt, offset, "linux,stdout-path", &l);
 960	if (!p || !l)
 961		return -ENOENT;
 962
 963	q = strchrnul(p, ':');
 964	if (*q != '\0')
 965		options = q + 1;
 966	l = q - p;
 967
 968	/* Get the node specified by stdout-path */
 969	offset = fdt_path_offset_namelen(fdt, p, l);
 970	if (offset < 0) {
 971		pr_warn("earlycon: stdout-path %.*s not found\n", l, p);
 972		return 0;
 973	}
 974
 975	for (match = __earlycon_table; match < __earlycon_table_end; match++) {
 976		if (!match->compatible[0])
 977			continue;
 978
 979		if (fdt_node_check_compatible(fdt, offset, match->compatible))
 980			continue;
 981
 982		ret = of_setup_earlycon(match, offset, options);
 983		if (!ret || ret == -EALREADY)
 984			return 0;
 985	}
 986	return -ENODEV;
 987}
 988#endif
 989
 990/*
 991 * early_init_dt_scan_root - fetch the top level address and size cells
 992 */
 993int __init early_init_dt_scan_root(void)
 994{
 995	const __be32 *prop;
 996	const void *fdt = initial_boot_params;
 997	int node = fdt_path_offset(fdt, "/");
 998
 999	if (node < 0)
1000		return -ENODEV;
1001
1002	dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
1003	dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
1004
1005	prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
1006	if (!WARN(!prop, "No '#size-cells' in root node\n"))
1007		dt_root_size_cells = be32_to_cpup(prop);
1008	pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells);
1009
1010	prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
1011	if (!WARN(!prop, "No '#address-cells' in root node\n"))
1012		dt_root_addr_cells = be32_to_cpup(prop);
1013	pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells);
1014
1015	return 0;
1016}
1017
1018u64 __init dt_mem_next_cell(int s, const __be32 **cellp)
1019{
1020	const __be32 *p = *cellp;
1021
1022	*cellp = p + s;
1023	return of_read_number(p, s);
1024}
1025
1026/*
1027 * early_init_dt_scan_memory - Look for and parse memory nodes
1028 */
1029int __init early_init_dt_scan_memory(void)
1030{
1031	int node, found_memory = 0;
1032	const void *fdt = initial_boot_params;
1033
1034	fdt_for_each_subnode(node, fdt, 0) {
1035		const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
1036		const __be32 *reg;
1037		int i, l;
1038		bool hotpluggable;
1039
1040		/* We are scanning "memory" nodes only */
1041		if (type == NULL || strcmp(type, "memory") != 0)
1042			continue;
1043
1044		if (!of_fdt_device_is_available(fdt, node))
1045			continue;
1046
1047		reg = of_flat_dt_get_addr_size_prop(node, "linux,usable-memory", &l);
1048		if (reg == NULL)
1049			reg = of_flat_dt_get_addr_size_prop(node, "reg", &l);
1050		if (reg == NULL)
1051			continue;
1052
1053		hotpluggable = of_get_flat_dt_prop(node, "hotpluggable", NULL);
1054
1055		pr_debug("memory scan node %s, reg {addr,size} entries %d,\n",
1056			 fdt_get_name(fdt, node, NULL), l);
1057
1058		for (i = 0; i < l; i++) {
1059			u64 base, size;
1060
1061			of_flat_dt_read_addr_size(reg, i, &base, &size);
1062
1063			if (size == 0)
1064				continue;
1065			pr_debug(" - %llx, %llx\n", base, size);
1066
1067			early_init_dt_add_memory_arch(base, size);
1068
1069			found_memory = 1;
1070
1071			if (!hotpluggable)
1072				continue;
1073
1074			if (memblock_mark_hotplug(base, size))
1075				pr_warn("failed to mark hotplug range 0x%llx - 0x%llx\n",
1076					base, base + size);
1077		}
1078	}
1079	return found_memory;
1080}
1081
1082int __init early_init_dt_scan_chosen(char *cmdline)
1083{
1084	int l, node;
1085	const char *p;
1086	const void *rng_seed;
1087	const void *fdt = initial_boot_params;
1088
1089	node = fdt_path_offset(fdt, "/chosen");
1090	if (node < 0)
1091		node = fdt_path_offset(fdt, "/chosen@0");
1092	if (node < 0)
1093		/* Handle the cmdline config options even if no /chosen node */
1094		goto handle_cmdline;
1095
1096	chosen_node_offset = node;
1097
1098	early_init_dt_check_for_initrd(node);
1099	early_init_dt_check_for_elfcorehdr(node);
1100
1101	rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l);
1102	if (rng_seed && l > 0) {
1103		add_bootloader_randomness(rng_seed, l);
1104
1105		/* try to clear seed so it won't be found. */
1106		fdt_nop_property(initial_boot_params, node, "rng-seed");
1107
1108		/* update CRC check value */
1109		of_fdt_crc32 = crc32_be(~0, initial_boot_params,
1110				fdt_totalsize(initial_boot_params));
1111	}
1112
1113	/* Retrieve command line */
1114	p = of_get_flat_dt_prop(node, "bootargs", &l);
1115	if (p != NULL && l > 0)
1116		strscpy(cmdline, p, min(l, COMMAND_LINE_SIZE));
1117
1118handle_cmdline:
1119	/*
1120	 * CONFIG_CMDLINE is meant to be a default in case nothing else
1121	 * managed to set the command line, unless CONFIG_CMDLINE_FORCE
1122	 * is set in which case we override whatever was found earlier.
1123	 */
1124#ifdef CONFIG_CMDLINE
1125#if defined(CONFIG_CMDLINE_EXTEND)
1126	strlcat(cmdline, " ", COMMAND_LINE_SIZE);
1127	strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1128#elif defined(CONFIG_CMDLINE_FORCE)
1129	strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1130#else
1131	/* No arguments from boot loader, use kernel's  cmdl*/
1132	if (!((char *)cmdline)[0])
1133		strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1134#endif
1135#endif /* CONFIG_CMDLINE */
1136
1137	pr_debug("Command line is: %s\n", (char *)cmdline);
1138
1139	return 0;
1140}
1141
1142#ifndef MIN_MEMBLOCK_ADDR
1143#define MIN_MEMBLOCK_ADDR	__pa(PAGE_OFFSET)
1144#endif
1145#ifndef MAX_MEMBLOCK_ADDR
1146#define MAX_MEMBLOCK_ADDR	((phys_addr_t)~0)
1147#endif
1148
1149void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
1150{
1151	const u64 phys_offset = MIN_MEMBLOCK_ADDR;
1152
1153	if (size < PAGE_SIZE - (base & ~PAGE_MASK)) {
1154		pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
1155			base, base + size);
1156		return;
1157	}
1158
1159	if (!PAGE_ALIGNED(base)) {
1160		size -= PAGE_SIZE - (base & ~PAGE_MASK);
1161		base = PAGE_ALIGN(base);
1162	}
1163	size &= PAGE_MASK;
1164
1165	if (base > MAX_MEMBLOCK_ADDR) {
1166		pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
1167			base, base + size);
1168		return;
1169	}
1170
1171	if (base + size - 1 > MAX_MEMBLOCK_ADDR) {
1172		pr_warn("Ignoring memory range 0x%llx - 0x%llx\n",
1173			((u64)MAX_MEMBLOCK_ADDR) + 1, base + size);
1174		size = MAX_MEMBLOCK_ADDR - base + 1;
1175	}
1176
1177	if (base + size < phys_offset) {
1178		pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
1179			base, base + size);
1180		return;
1181	}
1182	if (base < phys_offset) {
1183		pr_warn("Ignoring memory range 0x%llx - 0x%llx\n",
1184			base, phys_offset);
1185		size -= phys_offset - base;
1186		base = phys_offset;
1187	}
1188	memblock_add(base, size);
1189}
1190
1191static void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
1192{
1193	return memblock_alloc_or_panic(size, align);
1194}
1195
1196bool __init early_init_dt_verify(void *dt_virt, phys_addr_t dt_phys)
1197{
1198	if (!dt_virt)
1199		return false;
1200
1201	/* check device tree validity */
1202	if (fdt_check_header(dt_virt))
1203		return false;
1204
1205	/* Setup flat device-tree pointer */
1206	initial_boot_params = dt_virt;
1207	initial_boot_params_pa = dt_phys;
1208	of_fdt_crc32 = crc32_be(~0, initial_boot_params,
1209				fdt_totalsize(initial_boot_params));
1210
1211	/* Initialize {size,address}-cells info */
1212	early_init_dt_scan_root();
1213
1214	return true;
1215}
1216
1217
1218void __init early_init_dt_scan_nodes(void)
1219{
1220	int rc;
1221
1222	/* Retrieve various information from the /chosen node */
1223	rc = early_init_dt_scan_chosen(boot_command_line);
1224	if (rc)
1225		pr_warn("No chosen node found, continuing without\n");
1226
1227	/* Setup memory, calling early_init_dt_add_memory_arch */
1228	early_init_dt_scan_memory();
1229
1230	/* Handle linux,usable-memory-range property */
1231	early_init_dt_check_for_usable_mem_range();
1232
1233	/* Handle kexec handover */
1234	early_init_dt_check_kho();
1235}
1236
1237bool __init early_init_dt_scan(void *dt_virt, phys_addr_t dt_phys)
1238{
1239	bool status;
1240
1241	status = early_init_dt_verify(dt_virt, dt_phys);
1242	if (!status)
1243		return false;
1244
1245	early_init_dt_scan_nodes();
1246	return true;
1247}
1248
1249static void *__init copy_device_tree(void *fdt)
1250{
1251	int size;
1252	void *dt;
1253
1254	size = fdt_totalsize(fdt);
1255	dt = early_init_dt_alloc_memory_arch(size,
1256					     roundup_pow_of_two(FDT_V17_SIZE));
1257
1258	if (dt)
1259		memcpy(dt, fdt, size);
1260
1261	return dt;
1262}
1263
1264/**
1265 * unflatten_device_tree - create tree of device_nodes from flat blob
1266 *
1267 * unflattens the device-tree passed by the firmware, creating the
1268 * tree of struct device_node. It also fills the "name" and "type"
1269 * pointers of the nodes so the normal device-tree walking functions
1270 * can be used.
1271 */
1272void __init unflatten_device_tree(void)
1273{
1274	void *fdt = initial_boot_params;
1275
1276	/* Save the statically-placed regions in the reserved_mem array */
1277	fdt_scan_reserved_mem_reg_nodes();
1278
1279	/* Populate an empty root node when bootloader doesn't provide one */
1280	if (!fdt) {
1281		fdt = (void *) __dtb_empty_root_begin;
1282		/* fdt_totalsize() will be used for copy size */
1283		if (fdt_totalsize(fdt) >
1284		    __dtb_empty_root_end - __dtb_empty_root_begin) {
1285			pr_err("invalid size in dtb_empty_root\n");
1286			return;
1287		}
1288		of_fdt_crc32 = crc32_be(~0, fdt, fdt_totalsize(fdt));
1289		fdt = copy_device_tree(fdt);
1290	}
1291
1292	__unflatten_device_tree(fdt, NULL, &of_root,
1293				early_init_dt_alloc_memory_arch, false);
1294
1295	/* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */
1296	of_alias_scan(early_init_dt_alloc_memory_arch);
1297
1298	unittest_unflatten_overlay_base();
1299}
1300
1301/**
1302 * unflatten_and_copy_device_tree - copy and create tree of device_nodes from flat blob
1303 *
1304 * Copies and unflattens the device-tree passed by the firmware, creating the
1305 * tree of struct device_node. It also fills the "name" and "type"
1306 * pointers of the nodes so the normal device-tree walking functions
1307 * can be used. This should only be used when the FDT memory has not been
1308 * reserved such is the case when the FDT is built-in to the kernel init
1309 * section. If the FDT memory is reserved already then unflatten_device_tree
1310 * should be used instead.
1311 */
1312void __init unflatten_and_copy_device_tree(void)
1313{
1314	if (initial_boot_params)
1315		initial_boot_params = copy_device_tree(initial_boot_params);
1316
1317	unflatten_device_tree();
1318}
1319
1320#ifdef CONFIG_SYSFS
1321static int __init of_fdt_raw_init(void)
1322{
1323	static __ro_after_init BIN_ATTR_SIMPLE_ADMIN_RO(fdt);
1324
1325	if (!initial_boot_params)
1326		return 0;
1327
1328	if (of_fdt_crc32 != crc32_be(~0, initial_boot_params,
1329				     fdt_totalsize(initial_boot_params))) {
1330		pr_warn("not creating '/sys/firmware/fdt': CRC check failed\n");
1331		return 0;
1332	}
1333	bin_attr_fdt.private = initial_boot_params;
1334	bin_attr_fdt.size = fdt_totalsize(initial_boot_params);
1335	return sysfs_create_bin_file(firmware_kobj, &bin_attr_fdt);
1336}
1337late_initcall(of_fdt_raw_init);
1338#endif
1339
1340#endif /* CONFIG_OF_EARLY_FLATTREE */