drivers/of/fdt.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
of_fdt_limit_memory
of_fdt_device_is_available
unflatten_dt_alloc
populate_properties
populate_node
reverse_nodes
unflatten_dt_nodes
__unflatten_device_tree
kernel_tree_alloc
of_fdt_unflatten_tree
__reserved_mem_reserve_reg
__reserved_mem_check_root
__fdt_scan_reserved_mem
early_init_fdt_scan_reserved_mem
early_init_fdt_reserve_self
of_scan_flat_dt
of_scan_flat_dt_subnodes
of_get_flat_dt_subnode_by_name
of_get_flat_dt_root
of_get_flat_dt_prop
of_fdt_is_compatible
of_flat_dt_is_compatible
of_flat_dt_match
of_get_flat_dt_phandle
of_flat_dt_get_machine_name
of_flat_dt_match_machine
__early_init_dt_declare_initrd
early_init_dt_check_for_initrd
early_init_dt_check_for_initrd
early_init_dt_scan_chosen_stdout
early_init_dt_scan_root
dt_mem_next_cell
early_init_dt_scan_memory
early_init_dt_scan_chosen
early_init_dt_add_memory_arch
early_init_dt_mark_hotplug_memory_arch
early_init_dt_reserve_memory_arch
early_init_dt_alloc_memory_arch
early_init_dt_verify
early_init_dt_scan_nodes
early_init_dt_scan
unflatten_device_tree
unflatten_and_copy_device_tree
of_fdt_raw_read
of_fdt_raw_init
   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  */
  42 void __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 
  82 static 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 
  95 static 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 
 107 static 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 
 208 static 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 
 254 static 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  */
 287 static 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  */
 367 void *__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_warning("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 
 427 static void *kernel_tree_alloc(u64 size, u64 align)
 428 {
 429         return kzalloc(size, GFP_KERNEL);
 430 }
 431 
 432 static 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  */
 448 void *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 }
 461 EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree);
 462 
 463 /* Everything below here references initial_boot_params directly. */
 464 int __initdata dt_root_addr_cells;
 465 int __initdata dt_root_size_cells;
 466 
 467 void *initial_boot_params __ro_after_init;
 468 
 469 #ifdef CONFIG_OF_EARLY_FLATTREE
 470 
 471 static u32 of_fdt_crc32;
 472 
 473 /**
 474  * res_mem_reserve_reg() - reserve all memory described in 'reg' property
 475  */
 476 static 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  */
 524 static 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  */
 545 static 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  */
 586 void __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  */
 609 void __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  */
 629 int __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                 if (*pathp == '/')
 647                         pathp = kbasename(pathp);
 648                 rc = it(offset, pathp, depth, data);
 649         }
 650         return rc;
 651 }
 652 
 653 /**
 654  * of_scan_flat_dt_subnodes - scan sub-nodes of a node call callback on each.
 655  * @it: callback function
 656  * @data: context data pointer
 657  *
 658  * This function is used to scan sub-nodes of a node.
 659  */
 660 int __init of_scan_flat_dt_subnodes(unsigned long parent,
 661                                     int (*it)(unsigned long node,
 662                                               const char *uname,
 663                                               void *data),
 664                                     void *data)
 665 {
 666         const void *blob = initial_boot_params;
 667         int node;
 668 
 669         fdt_for_each_subnode(node, blob, parent) {
 670                 const char *pathp;
 671                 int rc;
 672 
 673                 pathp = fdt_get_name(blob, node, NULL);
 674                 if (*pathp == '/')
 675                         pathp = kbasename(pathp);
 676                 rc = it(node, pathp, data);
 677                 if (rc)
 678                         return rc;
 679         }
 680         return 0;
 681 }
 682 
 683 /**
 684  * of_get_flat_dt_subnode_by_name - get the subnode by given name
 685  *
 686  * @node: the parent node
 687  * @uname: the name of subnode
 688  * @return offset of the subnode, or -FDT_ERR_NOTFOUND if there is none
 689  */
 690 
 691 int __init of_get_flat_dt_subnode_by_name(unsigned long node, const char *uname)
 692 {
 693         return fdt_subnode_offset(initial_boot_params, node, uname);
 694 }
 695 
 696 /**
 697  * of_get_flat_dt_root - find the root node in the flat blob
 698  */
 699 unsigned long __init of_get_flat_dt_root(void)
 700 {
 701         return 0;
 702 }
 703 
 704 /**
 705  * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
 706  *
 707  * This function can be used within scan_flattened_dt callback to get
 708  * access to properties
 709  */
 710 const void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
 711                                        int *size)
 712 {
 713         return fdt_getprop(initial_boot_params, node, name, size);
 714 }
 715 
 716 /**
 717  * of_fdt_is_compatible - Return true if given node from the given blob has
 718  * compat in its compatible list
 719  * @blob: A device tree blob
 720  * @node: node to test
 721  * @compat: compatible string to compare with compatible list.
 722  *
 723  * On match, returns a non-zero value with smaller values returned for more
 724  * specific compatible values.
 725  */
 726 static int of_fdt_is_compatible(const void *blob,
 727                       unsigned long node, const char *compat)
 728 {
 729         const char *cp;
 730         int cplen;
 731         unsigned long l, score = 0;
 732 
 733         cp = fdt_getprop(blob, node, "compatible", &cplen);
 734         if (cp == NULL)
 735                 return 0;
 736         while (cplen > 0) {
 737                 score++;
 738                 if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
 739                         return score;
 740                 l = strlen(cp) + 1;
 741                 cp += l;
 742                 cplen -= l;
 743         }
 744 
 745         return 0;
 746 }
 747 
 748 /**
 749  * of_flat_dt_is_compatible - Return true if given node has compat in compatible list
 750  * @node: node to test
 751  * @compat: compatible string to compare with compatible list.
 752  */
 753 int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
 754 {
 755         return of_fdt_is_compatible(initial_boot_params, node, compat);
 756 }
 757 
 758 /**
 759  * of_flat_dt_match - Return true if node matches a list of compatible values
 760  */
 761 static int __init of_flat_dt_match(unsigned long node, const char *const *compat)
 762 {
 763         unsigned int tmp, score = 0;
 764 
 765         if (!compat)
 766                 return 0;
 767 
 768         while (*compat) {
 769                 tmp = of_fdt_is_compatible(initial_boot_params, node, *compat);
 770                 if (tmp && (score == 0 || (tmp < score)))
 771                         score = tmp;
 772                 compat++;
 773         }
 774 
 775         return score;
 776 }
 777 
 778 /**
 779  * of_get_flat_dt_prop - Given a node in the flat blob, return the phandle
 780  */
 781 uint32_t __init of_get_flat_dt_phandle(unsigned long node)
 782 {
 783         return fdt_get_phandle(initial_boot_params, node);
 784 }
 785 
 786 struct fdt_scan_status {
 787         const char *name;
 788         int namelen;
 789         int depth;
 790         int found;
 791         int (*iterator)(unsigned long node, const char *uname, int depth, void *data);
 792         void *data;
 793 };
 794 
 795 const char * __init of_flat_dt_get_machine_name(void)
 796 {
 797         const char *name;
 798         unsigned long dt_root = of_get_flat_dt_root();
 799 
 800         name = of_get_flat_dt_prop(dt_root, "model", NULL);
 801         if (!name)
 802                 name = of_get_flat_dt_prop(dt_root, "compatible", NULL);
 803         return name;
 804 }
 805 
 806 /**
 807  * of_flat_dt_match_machine - Iterate match tables to find matching machine.
 808  *
 809  * @default_match: A machine specific ptr to return in case of no match.
 810  * @get_next_compat: callback function to return next compatible match table.
 811  *
 812  * Iterate through machine match tables to find the best match for the machine
 813  * compatible string in the FDT.
 814  */
 815 const void * __init of_flat_dt_match_machine(const void *default_match,
 816                 const void * (*get_next_compat)(const char * const**))
 817 {
 818         const void *data = NULL;
 819         const void *best_data = default_match;
 820         const char *const *compat;
 821         unsigned long dt_root;
 822         unsigned int best_score = ~1, score = 0;
 823 
 824         dt_root = of_get_flat_dt_root();
 825         while ((data = get_next_compat(&compat))) {
 826                 score = of_flat_dt_match(dt_root, compat);
 827                 if (score > 0 && score < best_score) {
 828                         best_data = data;
 829                         best_score = score;
 830                 }
 831         }
 832         if (!best_data) {
 833                 const char *prop;
 834                 int size;
 835 
 836                 pr_err("\n unrecognized device tree list:\n[ ");
 837 
 838                 prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
 839                 if (prop) {
 840                         while (size > 0) {
 841                                 printk("'%s' ", prop);
 842                                 size -= strlen(prop) + 1;
 843                                 prop += strlen(prop) + 1;
 844                         }
 845                 }
 846                 printk("]\n\n");
 847                 return NULL;
 848         }
 849 
 850         pr_info("Machine model: %s\n", of_flat_dt_get_machine_name());
 851 
 852         return best_data;
 853 }
 854 
 855 #ifdef CONFIG_BLK_DEV_INITRD
 856 static void __early_init_dt_declare_initrd(unsigned long start,
 857                                            unsigned long end)
 858 {
 859         /* ARM64 would cause a BUG to occur here when CONFIG_DEBUG_VM is
 860          * enabled since __va() is called too early. ARM64 does make use
 861          * of phys_initrd_start/phys_initrd_size so we can skip this
 862          * conversion.
 863          */
 864         if (!IS_ENABLED(CONFIG_ARM64)) {
 865                 initrd_start = (unsigned long)__va(start);
 866                 initrd_end = (unsigned long)__va(end);
 867                 initrd_below_start_ok = 1;
 868         }
 869 }
 870 
 871 /**
 872  * early_init_dt_check_for_initrd - Decode initrd location from flat tree
 873  * @node: reference to node containing initrd location ('chosen')
 874  */
 875 static void __init early_init_dt_check_for_initrd(unsigned long node)
 876 {
 877         u64 start, end;
 878         int len;
 879         const __be32 *prop;
 880 
 881         pr_debug("Looking for initrd properties... ");
 882 
 883         prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);
 884         if (!prop)
 885                 return;
 886         start = of_read_number(prop, len/4);
 887 
 888         prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
 889         if (!prop)
 890                 return;
 891         end = of_read_number(prop, len/4);
 892 
 893         __early_init_dt_declare_initrd(start, end);
 894         phys_initrd_start = start;
 895         phys_initrd_size = end - start;
 896 
 897         pr_debug("initrd_start=0x%llx  initrd_end=0x%llx\n",
 898                  (unsigned long long)start, (unsigned long long)end);
 899 }
 900 #else
 901 static inline void early_init_dt_check_for_initrd(unsigned long node)
 902 {
 903 }
 904 #endif /* CONFIG_BLK_DEV_INITRD */
 905 
 906 #ifdef CONFIG_SERIAL_EARLYCON
 907 
 908 int __init early_init_dt_scan_chosen_stdout(void)
 909 {
 910         int offset;
 911         const char *p, *q, *options = NULL;
 912         int l;
 913         const struct earlycon_id **p_match;
 914         const void *fdt = initial_boot_params;
 915 
 916         offset = fdt_path_offset(fdt, "/chosen");
 917         if (offset < 0)
 918                 offset = fdt_path_offset(fdt, "/chosen@0");
 919         if (offset < 0)
 920                 return -ENOENT;
 921 
 922         p = fdt_getprop(fdt, offset, "stdout-path", &l);
 923         if (!p)
 924                 p = fdt_getprop(fdt, offset, "linux,stdout-path", &l);
 925         if (!p || !l)
 926                 return -ENOENT;
 927 
 928         q = strchrnul(p, ':');
 929         if (*q != '\0')
 930                 options = q + 1;
 931         l = q - p;
 932 
 933         /* Get the node specified by stdout-path */
 934         offset = fdt_path_offset_namelen(fdt, p, l);
 935         if (offset < 0) {
 936                 pr_warn("earlycon: stdout-path %.*s not found\n", l, p);
 937                 return 0;
 938         }
 939 
 940         for (p_match = __earlycon_table; p_match < __earlycon_table_end;
 941              p_match++) {
 942                 const struct earlycon_id *match = *p_match;
 943 
 944                 if (!match->compatible[0])
 945                         continue;
 946 
 947                 if (fdt_node_check_compatible(fdt, offset, match->compatible))
 948                         continue;
 949 
 950                 of_setup_earlycon(match, offset, options);
 951                 return 0;
 952         }
 953         return -ENODEV;
 954 }
 955 #endif
 956 
 957 /**
 958  * early_init_dt_scan_root - fetch the top level address and size cells
 959  */
 960 int __init early_init_dt_scan_root(unsigned long node, const char *uname,
 961                                    int depth, void *data)
 962 {
 963         const __be32 *prop;
 964 
 965         if (depth != 0)
 966                 return 0;
 967 
 968         dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
 969         dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
 970 
 971         prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
 972         if (prop)
 973                 dt_root_size_cells = be32_to_cpup(prop);
 974         pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells);
 975 
 976         prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
 977         if (prop)
 978                 dt_root_addr_cells = be32_to_cpup(prop);
 979         pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells);
 980 
 981         /* break now */
 982         return 1;
 983 }
 984 
 985 u64 __init dt_mem_next_cell(int s, const __be32 **cellp)
 986 {
 987         const __be32 *p = *cellp;
 988 
 989         *cellp = p + s;
 990         return of_read_number(p, s);
 991 }
 992 
 993 /**
 994  * early_init_dt_scan_memory - Look for and parse memory nodes
 995  */
 996 int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
 997                                      int depth, void *data)
 998 {
 999         const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
1000         const __be32 *reg, *endp;
1001         int l;
1002         bool hotpluggable;
1003 
1004         /* We are scanning "memory" nodes only */
1005         if (type == NULL || strcmp(type, "memory") != 0)
1006                 return 0;
1007 
1008         reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
1009         if (reg == NULL)
1010                 reg = of_get_flat_dt_prop(node, "reg", &l);
1011         if (reg == NULL)
1012                 return 0;
1013 
1014         endp = reg + (l / sizeof(__be32));
1015         hotpluggable = of_get_flat_dt_prop(node, "hotpluggable", NULL);
1016 
1017         pr_debug("memory scan node %s, reg size %d,\n", uname, l);
1018 
1019         while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
1020                 u64 base, size;
1021 
1022                 base = dt_mem_next_cell(dt_root_addr_cells, &reg);
1023                 size = dt_mem_next_cell(dt_root_size_cells, &reg);
1024 
1025                 if (size == 0)
1026                         continue;
1027                 pr_debug(" - %llx ,  %llx\n", (unsigned long long)base,
1028                     (unsigned long long)size);
1029 
1030                 early_init_dt_add_memory_arch(base, size);
1031 
1032                 if (!hotpluggable)
1033                         continue;
1034 
1035                 if (early_init_dt_mark_hotplug_memory_arch(base, size))
1036                         pr_warn("failed to mark hotplug range 0x%llx - 0x%llx\n",
1037                                 base, base + size);
1038         }
1039 
1040         return 0;
1041 }
1042 
1043 int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
1044                                      int depth, void *data)
1045 {
1046         int l;
1047         const char *p;
1048         const void *rng_seed;
1049 
1050         pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname);
1051 
1052         if (depth != 1 || !data ||
1053             (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
1054                 return 0;
1055 
1056         early_init_dt_check_for_initrd(node);
1057 
1058         /* Retrieve command line */
1059         p = of_get_flat_dt_prop(node, "bootargs", &l);
1060         if (p != NULL && l > 0)
1061                 strlcpy(data, p, min(l, COMMAND_LINE_SIZE));
1062 
1063         /*
1064          * CONFIG_CMDLINE is meant to be a default in case nothing else
1065          * managed to set the command line, unless CONFIG_CMDLINE_FORCE
1066          * is set in which case we override whatever was found earlier.
1067          */
1068 #ifdef CONFIG_CMDLINE
1069 #if defined(CONFIG_CMDLINE_EXTEND)
1070         strlcat(data, " ", COMMAND_LINE_SIZE);
1071         strlcat(data, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1072 #elif defined(CONFIG_CMDLINE_FORCE)
1073         strlcpy(data, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1074 #else
1075         /* No arguments from boot loader, use kernel's  cmdl*/
1076         if (!((char *)data)[0])
1077                 strlcpy(data, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1078 #endif
1079 #endif /* CONFIG_CMDLINE */
1080 
1081         pr_debug("Command line is: %s\n", (char*)data);
1082 
1083         rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l);
1084         if (rng_seed && l > 0) {
1085                 add_bootloader_randomness(rng_seed, l);
1086 
1087                 /* try to clear seed so it won't be found. */
1088                 fdt_nop_property(initial_boot_params, node, "rng-seed");
1089 
1090                 /* update CRC check value */
1091                 of_fdt_crc32 = crc32_be(~0, initial_boot_params,
1092                                 fdt_totalsize(initial_boot_params));
1093         }
1094 
1095         /* break now */
1096         return 1;
1097 }
1098 
1099 #ifndef MIN_MEMBLOCK_ADDR
1100 #define MIN_MEMBLOCK_ADDR       __pa(PAGE_OFFSET)
1101 #endif
1102 #ifndef MAX_MEMBLOCK_ADDR
1103 #define MAX_MEMBLOCK_ADDR       ((phys_addr_t)~0)
1104 #endif
1105 
1106 void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
1107 {
1108         const u64 phys_offset = MIN_MEMBLOCK_ADDR;
1109 
1110         if (size < PAGE_SIZE - (base & ~PAGE_MASK)) {
1111                 pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
1112                         base, base + size);
1113                 return;
1114         }
1115 
1116         if (!PAGE_ALIGNED(base)) {
1117                 size -= PAGE_SIZE - (base & ~PAGE_MASK);
1118                 base = PAGE_ALIGN(base);
1119         }
1120         size &= PAGE_MASK;
1121 
1122         if (base > MAX_MEMBLOCK_ADDR) {
1123                 pr_warning("Ignoring memory block 0x%llx - 0x%llx\n",
1124                                 base, base + size);
1125                 return;
1126         }
1127 
1128         if (base + size - 1 > MAX_MEMBLOCK_ADDR) {
1129                 pr_warning("Ignoring memory range 0x%llx - 0x%llx\n",
1130                                 ((u64)MAX_MEMBLOCK_ADDR) + 1, base + size);
1131                 size = MAX_MEMBLOCK_ADDR - base + 1;
1132         }
1133 
1134         if (base + size < phys_offset) {
1135                 pr_warning("Ignoring memory block 0x%llx - 0x%llx\n",
1136                            base, base + size);
1137                 return;
1138         }
1139         if (base < phys_offset) {
1140                 pr_warning("Ignoring memory range 0x%llx - 0x%llx\n",
1141                            base, phys_offset);
1142                 size -= phys_offset - base;
1143                 base = phys_offset;
1144         }
1145         memblock_add(base, size);
1146 }
1147 
1148 int __init __weak early_init_dt_mark_hotplug_memory_arch(u64 base, u64 size)
1149 {
1150         return memblock_mark_hotplug(base, size);
1151 }
1152 
1153 int __init __weak early_init_dt_reserve_memory_arch(phys_addr_t base,
1154                                         phys_addr_t size, bool nomap)
1155 {
1156         if (nomap)
1157                 return memblock_remove(base, size);
1158         return memblock_reserve(base, size);
1159 }
1160 
1161 static void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
1162 {
1163         void *ptr = memblock_alloc(size, align);
1164 
1165         if (!ptr)
1166                 panic("%s: Failed to allocate %llu bytes align=0x%llx\n",
1167                       __func__, size, align);
1168 
1169         return ptr;
1170 }
1171 
1172 bool __init early_init_dt_verify(void *params)
1173 {
1174         if (!params)
1175                 return false;
1176 
1177         /* check device tree validity */
1178         if (fdt_check_header(params))
1179                 return false;
1180 
1181         /* Setup flat device-tree pointer */
1182         initial_boot_params = params;
1183         of_fdt_crc32 = crc32_be(~0, initial_boot_params,
1184                                 fdt_totalsize(initial_boot_params));
1185         return true;
1186 }
1187 
1188 
1189 void __init early_init_dt_scan_nodes(void)
1190 {
1191         int rc = 0;
1192 
1193         /* Retrieve various information from the /chosen node */
1194         rc = of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line);
1195         if (!rc)
1196                 pr_warn("No chosen node found, continuing without\n");
1197 
1198         /* Initialize {size,address}-cells info */
1199         of_scan_flat_dt(early_init_dt_scan_root, NULL);
1200 
1201         /* Setup memory, calling early_init_dt_add_memory_arch */
1202         of_scan_flat_dt(early_init_dt_scan_memory, NULL);
1203 }
1204 
1205 bool __init early_init_dt_scan(void *params)
1206 {
1207         bool status;
1208 
1209         status = early_init_dt_verify(params);
1210         if (!status)
1211                 return false;
1212 
1213         early_init_dt_scan_nodes();
1214         return true;
1215 }
1216 
1217 /**
1218  * unflatten_device_tree - create tree of device_nodes from flat blob
1219  *
1220  * unflattens the device-tree passed by the firmware, creating the
1221  * tree of struct device_node. It also fills the "name" and "type"
1222  * pointers of the nodes so the normal device-tree walking functions
1223  * can be used.
1224  */
1225 void __init unflatten_device_tree(void)
1226 {
1227         __unflatten_device_tree(initial_boot_params, NULL, &of_root,
1228                                 early_init_dt_alloc_memory_arch, false);
1229 
1230         /* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */
1231         of_alias_scan(early_init_dt_alloc_memory_arch);
1232 
1233         unittest_unflatten_overlay_base();
1234 }
1235 
1236 /**
1237  * unflatten_and_copy_device_tree - copy and create tree of device_nodes from flat blob
1238  *
1239  * Copies and unflattens the device-tree passed by the firmware, creating the
1240  * tree of struct device_node. It also fills the "name" and "type"
1241  * pointers of the nodes so the normal device-tree walking functions
1242  * can be used. This should only be used when the FDT memory has not been
1243  * reserved such is the case when the FDT is built-in to the kernel init
1244  * section. If the FDT memory is reserved already then unflatten_device_tree
1245  * should be used instead.
1246  */
1247 void __init unflatten_and_copy_device_tree(void)
1248 {
1249         int size;
1250         void *dt;
1251 
1252         if (!initial_boot_params) {
1253                 pr_warn("No valid device tree found, continuing without\n");
1254                 return;
1255         }
1256 
1257         size = fdt_totalsize(initial_boot_params);
1258         dt = early_init_dt_alloc_memory_arch(size,
1259                                              roundup_pow_of_two(FDT_V17_SIZE));
1260 
1261         if (dt) {
1262                 memcpy(dt, initial_boot_params, size);
1263                 initial_boot_params = dt;
1264         }
1265         unflatten_device_tree();
1266 }
1267 
1268 #ifdef CONFIG_SYSFS
1269 static ssize_t of_fdt_raw_read(struct file *filp, struct kobject *kobj,
1270                                struct bin_attribute *bin_attr,
1271                                char *buf, loff_t off, size_t count)
1272 {
1273         memcpy(buf, initial_boot_params + off, count);
1274         return count;
1275 }
1276 
1277 static int __init of_fdt_raw_init(void)
1278 {
1279         static struct bin_attribute of_fdt_raw_attr =
1280                 __BIN_ATTR(fdt, S_IRUSR, of_fdt_raw_read, NULL, 0);
1281 
1282         if (!initial_boot_params)
1283                 return 0;
1284 
1285         if (of_fdt_crc32 != crc32_be(~0, initial_boot_params,
1286                                      fdt_totalsize(initial_boot_params))) {
1287                 pr_warn("not creating '/sys/firmware/fdt': CRC check failed\n");
1288                 return 0;
1289         }
1290         of_fdt_raw_attr.size = fdt_totalsize(initial_boot_params);
1291         return sysfs_create_bin_file(firmware_kobj, &of_fdt_raw_attr);
1292 }
1293 late_initcall(of_fdt_raw_init);
1294 #endif
1295 
1296 #endif /* CONFIG_OF_EARLY_FLATTREE */
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/of/fdt.c

DEFINITIONS
