drivers/of/fdt.c

   1 /*
   2  * Functions for working with the Flattened Device Tree data format
   3  *
   4  * Copyright 2009 Benjamin Herrenschmidt, IBM Corp
   5  * benh@kernel.crashing.org
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * version 2 as published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/initrd.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/of_fdt.h>
  17 #include <linux/string.h>
  18 #include <linux/errno.h>
  19 #include <linux/slab.h>
  20
  21 #ifdef CONFIG_PPC
  22 #include <asm/machdep.h>
  23 #endif /* CONFIG_PPC */
  24
  25 #include <asm/page.h>
  26
  27 char *of_fdt_get_string(struct boot_param_header *blob, u32 offset)
  28 {
  29         return ((char *)blob) +
  30                 be32_to_cpu(blob->off_dt_strings) + offset;
  31 }
  32
  33 /**
  34  * of_fdt_get_property - Given a node in the given flat blob, return
  35  * the property ptr
  36  */
  37 void *of_fdt_get_property(struct boot_param_header *blob,
  38                        unsigned long node, const char *name,
  39                        unsigned long *size)
  40 {
  41         unsigned long p = node;
  42
  43         do {
  44                 u32 tag = be32_to_cpup((__be32 *)p);
  45                 u32 sz, noff;
  46                 const char *nstr;
  47
  48                 p += 4;
  49                 if (tag == OF_DT_NOP)
  50                         continue;
  51                 if (tag != OF_DT_PROP)
  52                         return NULL;
  53
  54                 sz = be32_to_cpup((__be32 *)p);
  55                 noff = be32_to_cpup((__be32 *)(p + 4));
  56                 p += 8;
  57                 if (be32_to_cpu(blob->version) < 0x10)
  58                         p = ALIGN(p, sz >= 8 ? 8 : 4);
  59
  60                 nstr = of_fdt_get_string(blob, noff);
  61                 if (nstr == NULL) {
  62                         pr_warning("Can't find property index name !\n");
  63                         return NULL;
  64                 }
  65                 if (strcmp(name, nstr) == 0) {
  66                         if (size)
  67                                 *size = sz;
  68                         return (void *)p;
  69                 }
  70                 p += sz;
  71                 p = ALIGN(p, 4);
  72         } while (1);
  73 }
  74
  75 /**
  76  * of_fdt_is_compatible - Return true if given node from the given blob has
  77  * compat in its compatible list
  78  * @blob: A device tree blob
  79  * @node: node to test
  80  * @compat: compatible string to compare with compatible list.
  81  *
  82  * On match, returns a non-zero value with smaller values returned for more
  83  * specific compatible values.
  84  */
  85 int of_fdt_is_compatible(struct boot_param_header *blob,
  86                       unsigned long node, const char *compat)
  87 {
  88         const char *cp;
  89         unsigned long cplen, l, score = 0;
  90
  91         cp = of_fdt_get_property(blob, node, "compatible", &cplen);
  92         if (cp == NULL)
  93                 return 0;
  94         while (cplen > 0) {
  95                 score++;
  96                 if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
  97                         return score;
  98                 l = strlen(cp) + 1;
  99                 cp += l;
 100                 cplen -= l;
 101         }
 102
 103         return 0;
 104 }
 105
 106 /**
 107  * of_fdt_match - Return true if node matches a list of compatible values
 108  */
 109 int of_fdt_match(struct boot_param_header *blob, unsigned long node,
 110                  const char **compat)
 111 {
 112         unsigned int tmp, score = 0;
 113
 114         if (!compat)
 115                 return 0;
 116
 117         while (*compat) {
 118                 tmp = of_fdt_is_compatible(blob, node, *compat);
 119                 if (tmp && (score == 0 || (tmp < score)))
 120                         score = tmp;
 121                 compat++;
 122         }
 123
 124         return score;
 125 }
 126
 127 static void *unflatten_dt_alloc(unsigned long *mem, unsigned long size,
 128                                        unsigned long align)
 129 {
 130         void *res;
 131
 132         *mem = ALIGN(*mem, align);
 133         res = (void *)*mem;
 134         *mem += size;
 135
 136         return res;
 137 }
 138
 139 /**
 140  * unflatten_dt_node - Alloc and populate a device_node from the flat tree
 141  * @blob: The parent device tree blob
 142  * @p: pointer to node in flat tree
 143  * @dad: Parent struct device_node
 144  * @allnextpp: pointer to ->allnext from last allocated device_node
 145  * @fpsize: Size of the node path up at the current depth.
 146  */
 147 unsigned long unflatten_dt_node(struct boot_param_header *blob,
 148                                 unsigned long mem,
 149                                 unsigned long *p,
 150                                 struct device_node *dad,
 151                                 struct device_node ***allnextpp,
 152                                 unsigned long fpsize)
 153 {
 154         struct device_node *np;
 155         struct property *pp, **prev_pp = NULL;
 156         char *pathp;
 157         u32 tag;
 158         unsigned int l, allocl;
 159         int has_name = 0;
 160         int new_format = 0;
 161
 162         tag = be32_to_cpup((__be32 *)(*p));
 163         if (tag != OF_DT_BEGIN_NODE) {
 164                 pr_err("Weird tag at start of node: %x\n", tag);
 165                 return mem;
 166         }
 167         *p += 4;
 168         pathp = (char *)*p;
 169         l = allocl = strlen(pathp) + 1;
 170         *p = ALIGN(*p + l, 4);
 171
 172         /* version 0x10 has a more compact unit name here instead of the full
 173          * path. we accumulate the full path size using "fpsize", we'll rebuild
 174          * it later. We detect this because the first character of the name is
 175          * not '/'.
 176          */
 177         if ((*pathp) != '/') {
 178                 new_format = 1;
 179                 if (fpsize == 0) {
 180                         /* root node: special case. fpsize accounts for path
 181                          * plus terminating zero. root node only has '/', so
 182                          * fpsize should be 2, but we want to avoid the first
 183                          * level nodes to have two '/' so we use fpsize 1 here
 184                          */
 185                         fpsize = 1;
 186                         allocl = 2;
 187                 } else {
 188                         /* account for '/' and path size minus terminal 0
 189                          * already in 'l'
 190                          */
 191                         fpsize += l;
 192                         allocl = fpsize;
 193                 }
 194         }
 195
 196         np = unflatten_dt_alloc(&mem, sizeof(struct device_node) + allocl,
 197                                 __alignof__(struct device_node));
 198         if (allnextpp) {
 199                 memset(np, 0, sizeof(*np));
 200                 np->full_name = ((char *)np) + sizeof(struct device_node);
 201                 if (new_format) {
 202                         char *fn = np->full_name;
 203                         /* rebuild full path for new format */
 204                         if (dad && dad->parent) {
 205                                 strcpy(fn, dad->full_name);
 206 #ifdef DEBUG
 207                                 if ((strlen(fn) + l + 1) != allocl) {
 208                                         pr_debug("%s: p: %d, l: %d, a: %d\n",
 209                                                 pathp, (int)strlen(fn),
 210                                                 l, allocl);
 211                                 }
 212 #endif
 213                                 fn += strlen(fn);
 214                         }
 215                         *(fn++) = '/';
 216                         memcpy(fn, pathp, l);
 217                 } else
 218                         memcpy(np->full_name, pathp, l);
 219                 prev_pp = &np->properties;
 220                 **allnextpp = np;
 221                 *allnextpp = &np->allnext;
 222                 if (dad != NULL) {
 223                         np->parent = dad;
 224                         /* we temporarily use the next field as `last_child'*/
 225                         if (dad->next == NULL)
 226                                 dad->child = np;
 227                         else
 228                                 dad->next->sibling = np;
 229                         dad->next = np;
 230                 }
 231                 kref_init(&np->kref);
 232         }
 233         while (1) {
 234                 u32 sz, noff;
 235                 char *pname;
 236
 237                 tag = be32_to_cpup((__be32 *)(*p));
 238                 if (tag == OF_DT_NOP) {
 239                         *p += 4;
 240                         continue;
 241                 }
 242                 if (tag != OF_DT_PROP)
 243                         break;
 244                 *p += 4;
 245                 sz = be32_to_cpup((__be32 *)(*p));
 246                 noff = be32_to_cpup((__be32 *)((*p) + 4));
 247                 *p += 8;
 248                 if (be32_to_cpu(blob->version) < 0x10)
 249                         *p = ALIGN(*p, sz >= 8 ? 8 : 4);
 250
 251                 pname = of_fdt_get_string(blob, noff);
 252                 if (pname == NULL) {
 253                         pr_info("Can't find property name in list !\n");
 254                         break;
 255                 }
 256                 if (strcmp(pname, "name") == 0)
 257                         has_name = 1;
 258                 l = strlen(pname) + 1;
 259                 pp = unflatten_dt_alloc(&mem, sizeof(struct property),
 260                                         __alignof__(struct property));
 261                 if (allnextpp) {
 262                         /* We accept flattened tree phandles either in
 263                          * ePAPR-style "phandle" properties, or the
 264                          * legacy "linux,phandle" properties.  If both
 265                          * appear and have different values, things
 266                          * will get weird.  Don't do that. */
 267                         if ((strcmp(pname, "phandle") == 0) ||
 268                             (strcmp(pname, "linux,phandle") == 0)) {
 269                                 if (np->phandle == 0)
 270                                         np->phandle = be32_to_cpup((__be32*)*p);
 271                         }
 272                         /* And we process the "ibm,phandle" property
 273                          * used in pSeries dynamic device tree
 274                          * stuff */
 275                         if (strcmp(pname, "ibm,phandle") == 0)
 276                                 np->phandle = be32_to_cpup((__be32 *)*p);
 277                         pp->name = pname;
 278                         pp->length = sz;
 279                         pp->value = (void *)*p;
 280                         *prev_pp = pp;
 281                         prev_pp = &pp->next;
 282                 }
 283                 *p = ALIGN((*p) + sz, 4);
 284         }
 285         /* with version 0x10 we may not have the name property, recreate
 286          * it here from the unit name if absent
 287          */
 288         if (!has_name) {
 289                 char *p1 = pathp, *ps = pathp, *pa = NULL;
 290                 int sz;
 291
 292                 while (*p1) {
 293                         if ((*p1) == '@')
 294                                 pa = p1;
 295                         if ((*p1) == '/')
 296                                 ps = p1 + 1;
 297                         p1++;
 298                 }
 299                 if (pa < ps)
 300                         pa = p1;
 301                 sz = (pa - ps) + 1;
 302                 pp = unflatten_dt_alloc(&mem, sizeof(struct property) + sz,
 303                                         __alignof__(struct property));
 304                 if (allnextpp) {
 305                         pp->name = "name";
 306                         pp->length = sz;
 307                         pp->value = pp + 1;
 308                         *prev_pp = pp;
 309                         prev_pp = &pp->next;
 310                         memcpy(pp->value, ps, sz - 1);
 311                         ((char *)pp->value)[sz - 1] = 0;
 312                         pr_debug("fixed up name for %s -> %s\n", pathp,
 313                                 (char *)pp->value);
 314                 }
 315         }
 316         if (allnextpp) {
 317                 *prev_pp = NULL;
 318                 np->name = of_get_property(np, "name", NULL);
 319                 np->type = of_get_property(np, "device_type", NULL);
 320
 321                 if (!np->name)
 322                         np->name = "<NULL>";
 323                 if (!np->type)
 324                         np->type = "<NULL>";
 325         }
 326         while (tag == OF_DT_BEGIN_NODE || tag == OF_DT_NOP) {
 327                 if (tag == OF_DT_NOP)
 328                         *p += 4;
 329                 else
 330                         mem = unflatten_dt_node(blob, mem, p, np, allnextpp,
 331                                                 fpsize);
 332                 tag = be32_to_cpup((__be32 *)(*p));
 333         }
 334         if (tag != OF_DT_END_NODE) {
 335                 pr_err("Weird tag at end of node: %x\n", tag);
 336                 return mem;
 337         }
 338         *p += 4;
 339         return mem;
 340 }
 341
 342 /**
 343  * __unflatten_device_tree - create tree of device_nodes from flat blob
 344  *
 345  * unflattens a device-tree, creating the
 346  * tree of struct device_node. It also fills the "name" and "type"
 347  * pointers of the nodes so the normal device-tree walking functions
 348  * can be used.
 349  * @blob: The blob to expand
 350  * @mynodes: The device_node tree created by the call
 351  * @dt_alloc: An allocator that provides a virtual address to memory
 352  * for the resulting tree
 353  */
 354 void __unflatten_device_tree(struct boot_param_header *blob,
 355                              struct device_node **mynodes,
 356                              void * (*dt_alloc)(u64 size, u64 align))
 357 {
 358         unsigned long start, mem, size;
 359         struct device_node **allnextp = mynodes;
 360
 361         pr_debug(" -> unflatten_device_tree()\n");
 362
 363         if (!blob) {
 364                 pr_debug("No device tree pointer\n");
 365                 return;
 366         }
 367
 368         pr_debug("Unflattening device tree:\n");
 369         pr_debug("magic: %08x\n", be32_to_cpu(blob->magic));
 370         pr_debug("size: %08x\n", be32_to_cpu(blob->totalsize));
 371         pr_debug("version: %08x\n", be32_to_cpu(blob->version));
 372
 373         if (be32_to_cpu(blob->magic) != OF_DT_HEADER) {
 374                 pr_err("Invalid device tree blob header\n");
 375                 return;
 376         }
 377
 378         /* First pass, scan for size */
 379         start = ((unsigned long)blob) +
 380                 be32_to_cpu(blob->off_dt_struct);
 381         size = unflatten_dt_node(blob, 0, &start, NULL, NULL, 0);
 382         size = (size | 3) + 1;
 383
 384         pr_debug("  size is %lx, allocating...\n", size);
 385
 386         /* Allocate memory for the expanded device tree */
 387         mem = (unsigned long)
 388                 dt_alloc(size + 4, __alignof__(struct device_node));
 389
 390         ((__be32 *)mem)[size / 4] = cpu_to_be32(0xdeadbeef);
 391
 392         pr_debug("  unflattening %lx...\n", mem);
 393
 394         /* Second pass, do actual unflattening */
 395         start = ((unsigned long)blob) +
 396                 be32_to_cpu(blob->off_dt_struct);
 397         unflatten_dt_node(blob, mem, &start, NULL, &allnextp, 0);
 398         if (be32_to_cpup((__be32 *)start) != OF_DT_END)
 399                 pr_warning("Weird tag at end of tree: %08x\n", *((u32 *)start));
 400         if (be32_to_cpu(((__be32 *)mem)[size / 4]) != 0xdeadbeef)
 401                 pr_warning("End of tree marker overwritten: %08x\n",
 402                            be32_to_cpu(((__be32 *)mem)[size / 4]));
 403         *allnextp = NULL;
 404
 405         pr_debug(" <- unflatten_device_tree()\n");
 406 }
 407
 408 static void *kernel_tree_alloc(u64 size, u64 align)
 409 {
 410         return kzalloc(size, GFP_KERNEL);
 411 }
 412
 413 /**
 414  * of_fdt_unflatten_tree - create tree of device_nodes from flat blob
 415  *
 416  * unflattens the device-tree passed by the firmware, creating the
 417  * tree of struct device_node. It also fills the "name" and "type"
 418  * pointers of the nodes so the normal device-tree walking functions
 419  * can be used.
 420  */
 421 void of_fdt_unflatten_tree(unsigned long *blob,
 422                         struct device_node **mynodes)
 423 {
 424         struct boot_param_header *device_tree =
 425                 (struct boot_param_header *)blob;
 426         __unflatten_device_tree(device_tree, mynodes, &kernel_tree_alloc);
 427 }
 428 EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree);
 429
 430 /* Everything below here references initial_boot_params directly. */
 431 int __initdata dt_root_addr_cells;
 432 int __initdata dt_root_size_cells;
 433
 434 struct boot_param_header *initial_boot_params;
 435
 436 #ifdef CONFIG_OF_EARLY_FLATTREE
 437
 438 /**
 439  * of_scan_flat_dt - scan flattened tree blob and call callback on each.
 440  * @it: callback function
 441  * @data: context data pointer
 442  *
 443  * This function is used to scan the flattened device-tree, it is
 444  * used to extract the memory information at boot before we can
 445  * unflatten the tree
 446  */
 447 int __init of_scan_flat_dt(int (*it)(unsigned long node,
 448                                      const char *uname, int depth,
 449                                      void *data),
 450                            void *data)
 451 {
 452         unsigned long p = ((unsigned long)initial_boot_params) +
 453                 be32_to_cpu(initial_boot_params->off_dt_struct);
 454         int rc = 0;
 455         int depth = -1;
 456
 457         do {
 458                 u32 tag = be32_to_cpup((__be32 *)p);
 459                 char *pathp;
 460
 461                 p += 4;
 462                 if (tag == OF_DT_END_NODE) {
 463                         depth--;
 464                         continue;
 465                 }
 466                 if (tag == OF_DT_NOP)
 467                         continue;
 468                 if (tag == OF_DT_END)
 469                         break;
 470                 if (tag == OF_DT_PROP) {
 471                         u32 sz = be32_to_cpup((__be32 *)p);
 472                         p += 8;
 473                         if (be32_to_cpu(initial_boot_params->version) < 0x10)
 474                                 p = ALIGN(p, sz >= 8 ? 8 : 4);
 475                         p += sz;
 476                         p = ALIGN(p, 4);
 477                         continue;
 478                 }
 479                 if (tag != OF_DT_BEGIN_NODE) {
 480                         pr_err("Invalid tag %x in flat device tree!\n", tag);
 481                         return -EINVAL;
 482                 }
 483                 depth++;
 484                 pathp = (char *)p;
 485                 p = ALIGN(p + strlen(pathp) + 1, 4);
 486                 if ((*pathp) == '/') {
 487                         char *lp, *np;
 488                         for (lp = NULL, np = pathp; *np; np++)
 489                                 if ((*np) == '/')
 490                                         lp = np+1;
 491                         if (lp != NULL)
 492                                 pathp = lp;
 493                 }
 494                 rc = it(p, pathp, depth, data);
 495                 if (rc != 0)
 496                         break;
 497         } while (1);
 498
 499         return rc;
 500 }
 501
 502 /**
 503  * of_get_flat_dt_root - find the root node in the flat blob
 504  */
 505 unsigned long __init of_get_flat_dt_root(void)
 506 {
 507         unsigned long p = ((unsigned long)initial_boot_params) +
 508                 be32_to_cpu(initial_boot_params->off_dt_struct);
 509
 510         while (be32_to_cpup((__be32 *)p) == OF_DT_NOP)
 511                 p += 4;
 512         BUG_ON(be32_to_cpup((__be32 *)p) != OF_DT_BEGIN_NODE);
 513         p += 4;
 514         return ALIGN(p + strlen((char *)p) + 1, 4);
 515 }
 516
 517 /**
 518  * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
 519  *
 520  * This function can be used within scan_flattened_dt callback to get
 521  * access to properties
 522  */
 523 void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
 524                                  unsigned long *size)
 525 {
 526         return of_fdt_get_property(initial_boot_params, node, name, size);
 527 }
 528
 529 /**
 530  * of_flat_dt_is_compatible - Return true if given node has compat in compatible list
 531  * @node: node to test
 532  * @compat: compatible string to compare with compatible list.
 533  */
 534 int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
 535 {
 536         return of_fdt_is_compatible(initial_boot_params, node, compat);
 537 }
 538
 539 /**
 540  * of_flat_dt_match - Return true if node matches a list of compatible values
 541  */
 542 int __init of_flat_dt_match(unsigned long node, const char **compat)
 543 {
 544         return of_fdt_match(initial_boot_params, node, compat);
 545 }
 546
 547 #ifdef CONFIG_BLK_DEV_INITRD
 548 /**
 549  * early_init_dt_check_for_initrd - Decode initrd location from flat tree
 550  * @node: reference to node containing initrd location ('chosen')
 551  */
 552 void __init early_init_dt_check_for_initrd(unsigned long node)
 553 {
 554         unsigned long start, end, len;
 555         __be32 *prop;
 556
 557         pr_debug("Looking for initrd properties... ");
 558
 559         prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);
 560         if (!prop)
 561                 return;
 562         start = of_read_ulong(prop, len/4);
 563
 564         prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
 565         if (!prop)
 566                 return;
 567         end = of_read_ulong(prop, len/4);
 568
 569         early_init_dt_setup_initrd_arch(start, end);
 570         pr_debug("initrd_start=0x%lx  initrd_end=0x%lx\n", start, end);
 571 }
 572 #else
 573 inline void early_init_dt_check_for_initrd(unsigned long node)
 574 {
 575 }
 576 #endif /* CONFIG_BLK_DEV_INITRD */
 577
 578 /**
 579  * early_init_dt_scan_root - fetch the top level address and size cells
 580  */
 581 int __init early_init_dt_scan_root(unsigned long node, const char *uname,
 582                                    int depth, void *data)
 583 {
 584         __be32 *prop;
 585
 586         if (depth != 0)
 587                 return 0;
 588
 589         dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
 590         dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
 591
 592         prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
 593         if (prop)
 594                 dt_root_size_cells = be32_to_cpup(prop);
 595         pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells);
 596
 597         prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
 598         if (prop)
 599                 dt_root_addr_cells = be32_to_cpup(prop);
 600         pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells);
 601
 602         /* break now */
 603         return 1;
 604 }
 605
 606 u64 __init dt_mem_next_cell(int s, __be32 **cellp)
 607 {
 608         __be32 *p = *cellp;
 609
 610         *cellp = p + s;
 611         return of_read_number(p, s);
 612 }
 613
 614 /**
 615  * early_init_dt_scan_memory - Look for an parse memory nodes
 616  */
 617 int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
 618                                      int depth, void *data)
 619 {
 620         char *type = of_get_flat_dt_prop(node, "device_type", NULL);
 621         __be32 *reg, *endp;
 622         unsigned long l;
 623
 624         /* We are scanning "memory" nodes only */
 625         if (type == NULL) {
 626                 /*
 627                  * The longtrail doesn't have a device_type on the
 628                  * /memory node, so look for the node called /memory@0.
 629                  */
 630                 if (depth != 1 || strcmp(uname, "memory@0") != 0)
 631                         return 0;
 632         } else if (strcmp(type, "memory") != 0)
 633                 return 0;
 634
 635         reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
 636         if (reg == NULL)
 637                 reg = of_get_flat_dt_prop(node, "reg", &l);
 638         if (reg == NULL)
 639                 return 0;
 640
 641         endp = reg + (l / sizeof(__be32));
 642
 643         pr_debug("memory scan node %s, reg size %ld, data: %x %x %x %x,\n",
 644             uname, l, reg[0], reg[1], reg[2], reg[3]);
 645
 646         while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
 647                 u64 base, size;
 648
 649                 base = dt_mem_next_cell(dt_root_addr_cells, &reg);
 650                 size = dt_mem_next_cell(dt_root_size_cells, &reg);
 651
 652                 if (size == 0)
 653                         continue;
 654                 pr_debug(" - %llx ,  %llx\n", (unsigned long long)base,
 655                     (unsigned long long)size);
 656
 657                 early_init_dt_add_memory_arch(base, size);
 658         }
 659
 660         return 0;
 661 }
 662
 663 int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
 664                                      int depth, void *data)
 665 {
 666         unsigned long l;
 667         char *p;
 668
 669         pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname);
 670
 671         if (depth != 1 ||
 672             (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
 673                 return 0;
 674
 675         early_init_dt_check_for_initrd(node);
 676
 677         /* Retreive command line */
 678         p = of_get_flat_dt_prop(node, "bootargs", &l);
 679         if (p != NULL && l > 0)
 680                 strlcpy(cmd_line, p, min((int)l, COMMAND_LINE_SIZE));
 681
 682 #ifdef CONFIG_CMDLINE
 683 #ifndef CONFIG_CMDLINE_FORCE
 684         if (p == NULL || l == 0 || (l == 1 && (*p) == 0))
 685 #endif
 686                 strlcpy(cmd_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 687 #endif /* CONFIG_CMDLINE */
 688
 689         pr_debug("Command line is: %s\n", cmd_line);
 690
 691         /* break now */
 692         return 1;
 693 }
 694
 695 /**
 696  * unflatten_device_tree - create tree of device_nodes from flat blob
 697  *
 698  * unflattens the device-tree passed by the firmware, creating the
 699  * tree of struct device_node. It also fills the "name" and "type"
 700  * pointers of the nodes so the normal device-tree walking functions
 701  * can be used.
 702  */
 703 void __init unflatten_device_tree(void)
 704 {
 705         __unflatten_device_tree(initial_boot_params, &allnodes,
 706                                 early_init_dt_alloc_memory_arch);
 707
 708         /* Get pointer to OF "/chosen" node for use everywhere */
 709         of_chosen = of_find_node_by_path("/chosen");
 710         if (of_chosen == NULL)
 711                 of_chosen = of_find_node_by_path("/chosen@0");
 712 }
 713
 714 #endif /* CONFIG_OF_EARLY_FLATTREE */