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/memblock.h>
  15 #include <linux/module.h>
  16 #include <linux/of.h>
  17 #include <linux/of_fdt.h>
  18 #include <linux/string.h>
  19 #include <linux/errno.h>
  20 #include <linux/slab.h>
  21
  22 #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
  23 #ifdef CONFIG_PPC
  24 #include <asm/machdep.h>
  25 #endif /* CONFIG_PPC */
  26
  27 #include <asm/page.h>
  28
  29 char *of_fdt_get_string(struct boot_param_header *blob, u32 offset)
  30 {
  31         return ((char *)blob) +
  32                 be32_to_cpu(blob->off_dt_strings) + offset;
  33 }
  34
  35 /**
  36  * of_fdt_get_property - Given a node in the given flat blob, return
  37  * the property ptr
  38  */
  39 void *of_fdt_get_property(struct boot_param_header *blob,
  40                        unsigned long node, const char *name,
  41                        unsigned long *size)
  42 {
  43         unsigned long p = node;
  44
  45         do {
  46                 u32 tag = be32_to_cpup((__be32 *)p);
  47                 u32 sz, noff;
  48                 const char *nstr;
  49
  50                 p += 4;
  51                 if (tag == OF_DT_NOP)
  52                         continue;
  53                 if (tag != OF_DT_PROP)
  54                         return NULL;
  55
  56                 sz = be32_to_cpup((__be32 *)p);
  57                 noff = be32_to_cpup((__be32 *)(p + 4));
  58                 p += 8;
  59                 if (be32_to_cpu(blob->version) < 0x10)
  60                         p = ALIGN(p, sz >= 8 ? 8 : 4);
  61
  62                 nstr = of_fdt_get_string(blob, noff);
  63                 if (nstr == NULL) {
  64                         pr_warning("Can't find property index name !\n");
  65                         return NULL;
  66                 }
  67                 if (strcmp(name, nstr) == 0) {
  68                         if (size)
  69                                 *size = sz;
  70                         return (void *)p;
  71                 }
  72                 p += sz;
  73                 p = ALIGN(p, 4);
  74         } while (1);
  75 }
  76
  77 /**
  78  * of_fdt_is_compatible - Return true if given node from the given blob has
  79  * compat in its compatible list
  80  * @blob: A device tree blob
  81  * @node: node to test
  82  * @compat: compatible string to compare with compatible list.
  83  *
  84  * On match, returns a non-zero value with smaller values returned for more
  85  * specific compatible values.
  86  */
  87 int of_fdt_is_compatible(struct boot_param_header *blob,
  88                       unsigned long node, const char *compat)
  89 {
  90         const char *cp;
  91         unsigned long cplen, l, score = 0;
  92
  93         cp = of_fdt_get_property(blob, node, "compatible", &cplen);
  94         if (cp == NULL)
  95                 return 0;
  96         while (cplen > 0) {
  97                 score++;
  98                 if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
  99                         return score;
 100                 l = strlen(cp) + 1;
 101                 cp += l;
 102                 cplen -= l;
 103         }
 104
 105         return 0;
 106 }
 107
 108 /**
 109  * of_fdt_match - Return true if node matches a list of compatible values
 110  */
 111 int of_fdt_match(struct boot_param_header *blob, unsigned long node,
 112                  const char *const *compat)
 113 {
 114         unsigned int tmp, score = 0;
 115
 116         if (!compat)
 117                 return 0;
 118
 119         while (*compat) {
 120                 tmp = of_fdt_is_compatible(blob, node, *compat);
 121                 if (tmp && (score == 0 || (tmp < score)))
 122                         score = tmp;
 123                 compat++;
 124         }
 125
 126         return score;
 127 }
 128
 129 static void *unflatten_dt_alloc(void **mem, unsigned long size,
 130                                        unsigned long align)
 131 {
 132         void *res;
 133
 134         *mem = PTR_ALIGN(*mem, align);
 135         res = *mem;
 136         *mem += size;
 137
 138         return res;
 139 }
 140
 141 /**
 142  * unflatten_dt_node - Alloc and populate a device_node from the flat tree
 143  * @blob: The parent device tree blob
 144  * @mem: Memory chunk to use for allocating device nodes and properties
 145  * @p: pointer to node in flat tree
 146  * @dad: Parent struct device_node
 147  * @allnextpp: pointer to ->allnext from last allocated device_node
 148  * @fpsize: Size of the node path up at the current depth.
 149  */
 150 static void * unflatten_dt_node(struct boot_param_header *blob,
 151                                 void *mem,
 152                                 void **p,
 153                                 struct device_node *dad,
 154                                 struct device_node ***allnextpp,
 155                                 unsigned long fpsize)
 156 {
 157         struct device_node *np;
 158         struct property *pp, **prev_pp = NULL;
 159         char *pathp;
 160         u32 tag;
 161         unsigned int l, allocl;
 162         int has_name = 0;
 163         int new_format = 0;
 164
 165         tag = be32_to_cpup(*p);
 166         if (tag != OF_DT_BEGIN_NODE) {
 167                 pr_err("Weird tag at start of node: %x\n", tag);
 168                 return mem;
 169         }
 170         *p += 4;
 171         pathp = *p;
 172         l = allocl = strlen(pathp) + 1;
 173         *p = PTR_ALIGN(*p + l, 4);
 174
 175         /* version 0x10 has a more compact unit name here instead of the full
 176          * path. we accumulate the full path size using "fpsize", we'll rebuild
 177          * it later. We detect this because the first character of the name is
 178          * not '/'.
 179          */
 180         if ((*pathp) != '/') {
 181                 new_format = 1;
 182                 if (fpsize == 0) {
 183                         /* root node: special case. fpsize accounts for path
 184                          * plus terminating zero. root node only has '/', so
 185                          * fpsize should be 2, but we want to avoid the first
 186                          * level nodes to have two '/' so we use fpsize 1 here
 187                          */
 188                         fpsize = 1;
 189                         allocl = 2;
 190                         l = 1;
 191                         *pathp = '\0';
 192                 } else {
 193                         /* account for '/' and path size minus terminal 0
 194                          * already in 'l'
 195                          */
 196                         fpsize += l;
 197                         allocl = fpsize;
 198                 }
 199         }
 200
 201         np = unflatten_dt_alloc(&mem, sizeof(struct device_node) + allocl,
 202                                 __alignof__(struct device_node));
 203         if (allnextpp) {
 204                 char *fn;
 205                 np->full_name = fn = ((char *)np) + sizeof(*np);
 206                 if (new_format) {
 207                         /* rebuild full path for new format */
 208                         if (dad && dad->parent) {
 209                                 strcpy(fn, dad->full_name);
 210 #ifdef DEBUG
 211                                 if ((strlen(fn) + l + 1) != allocl) {
 212                                         pr_debug("%s: p: %d, l: %d, a: %d\n",
 213                                                 pathp, (int)strlen(fn),
 214                                                 l, allocl);
 215                                 }
 216 #endif
 217                                 fn += strlen(fn);
 218                         }
 219                         *(fn++) = '/';
 220                 }
 221                 memcpy(fn, pathp, l);
 222
 223                 prev_pp = &np->properties;
 224                 **allnextpp = np;
 225                 *allnextpp = &np->allnext;
 226                 if (dad != NULL) {
 227                         np->parent = dad;
 228                         /* we temporarily use the next field as `last_child'*/
 229                         if (dad->next == NULL)
 230                                 dad->child = np;
 231                         else
 232                                 dad->next->sibling = np;
 233                         dad->next = np;
 234                 }
 235                 kref_init(&np->kref);
 236         }
 237         /* process properties */
 238         while (1) {
 239                 u32 sz, noff;
 240                 char *pname;
 241
 242                 tag = be32_to_cpup(*p);
 243                 if (tag == OF_DT_NOP) {
 244                         *p += 4;
 245                         continue;
 246                 }
 247                 if (tag != OF_DT_PROP)
 248                         break;
 249                 *p += 4;
 250                 sz = be32_to_cpup(*p);
 251                 noff = be32_to_cpup(*p + 4);
 252                 *p += 8;
 253                 if (be32_to_cpu(blob->version) < 0x10)
 254                         *p = PTR_ALIGN(*p, sz >= 8 ? 8 : 4);
 255
 256                 pname = of_fdt_get_string(blob, noff);
 257                 if (pname == NULL) {
 258                         pr_info("Can't find property name in list !\n");
 259                         break;
 260                 }
 261                 if (strcmp(pname, "name") == 0)
 262                         has_name = 1;
 263                 l = strlen(pname) + 1;
 264                 pp = unflatten_dt_alloc(&mem, sizeof(struct property),
 265                                         __alignof__(struct property));
 266                 if (allnextpp) {
 267                         /* We accept flattened tree phandles either in
 268                          * ePAPR-style "phandle" properties, or the
 269                          * legacy "linux,phandle" properties.  If both
 270                          * appear and have different values, things
 271                          * will get weird.  Don't do that. */
 272                         if ((strcmp(pname, "phandle") == 0) ||
 273                             (strcmp(pname, "linux,phandle") == 0)) {
 274                                 if (np->phandle == 0)
 275                                         np->phandle = be32_to_cpup((__be32*)*p);
 276                         }
 277                         /* And we process the "ibm,phandle" property
 278                          * used in pSeries dynamic device tree
 279                          * stuff */
 280                         if (strcmp(pname, "ibm,phandle") == 0)
 281                                 np->phandle = be32_to_cpup((__be32 *)*p);
 282                         pp->name = pname;
 283                         pp->length = sz;
 284                         pp->value = *p;
 285                         *prev_pp = pp;
 286                         prev_pp = &pp->next;
 287                 }
 288                 *p = PTR_ALIGN((*p) + sz, 4);
 289         }
 290         /* with version 0x10 we may not have the name property, recreate
 291          * it here from the unit name if absent
 292          */
 293         if (!has_name) {
 294                 char *p1 = pathp, *ps = pathp, *pa = NULL;
 295                 int sz;
 296
 297                 while (*p1) {
 298                         if ((*p1) == '@')
 299                                 pa = p1;
 300                         if ((*p1) == '/')
 301                                 ps = p1 + 1;
 302                         p1++;
 303                 }
 304                 if (pa < ps)
 305                         pa = p1;
 306                 sz = (pa - ps) + 1;
 307                 pp = unflatten_dt_alloc(&mem, sizeof(struct property) + sz,
 308                                         __alignof__(struct property));
 309                 if (allnextpp) {
 310                         pp->name = "name";
 311                         pp->length = sz;
 312                         pp->value = pp + 1;
 313                         *prev_pp = pp;
 314                         prev_pp = &pp->next;
 315                         memcpy(pp->value, ps, sz - 1);
 316                         ((char *)pp->value)[sz - 1] = 0;
 317                         pr_debug("fixed up name for %s -> %s\n", pathp,
 318                                 (char *)pp->value);
 319                 }
 320         }
 321         if (allnextpp) {
 322                 *prev_pp = NULL;
 323                 np->name = of_get_property(np, "name", NULL);
 324                 np->type = of_get_property(np, "device_type", NULL);
 325
 326                 if (!np->name)
 327                         np->name = "<NULL>";
 328                 if (!np->type)
 329                         np->type = "<NULL>";
 330         }
 331         while (tag == OF_DT_BEGIN_NODE || tag == OF_DT_NOP) {
 332                 if (tag == OF_DT_NOP)
 333                         *p += 4;
 334                 else
 335                         mem = unflatten_dt_node(blob, mem, p, np, allnextpp,
 336                                                 fpsize);
 337                 tag = be32_to_cpup(*p);
 338         }
 339         if (tag != OF_DT_END_NODE) {
 340                 pr_err("Weird tag at end of node: %x\n", tag);
 341                 return mem;
 342         }
 343         *p += 4;
 344         return mem;
 345 }
 346
 347 /**
 348  * __unflatten_device_tree - create tree of device_nodes from flat blob
 349  *
 350  * unflattens a device-tree, creating the
 351  * tree of struct device_node. It also fills the "name" and "type"
 352  * pointers of the nodes so the normal device-tree walking functions
 353  * can be used.
 354  * @blob: The blob to expand
 355  * @mynodes: The device_node tree created by the call
 356  * @dt_alloc: An allocator that provides a virtual address to memory
 357  * for the resulting tree
 358  */
 359 static void __unflatten_device_tree(struct boot_param_header *blob,
 360                              struct device_node **mynodes,
 361                              void * (*dt_alloc)(u64 size, u64 align))
 362 {
 363         unsigned long size;
 364         void *start, *mem;
 365         struct device_node **allnextp = mynodes;
 366
 367         pr_debug(" -> unflatten_device_tree()\n");
 368
 369         if (!blob) {
 370                 pr_debug("No device tree pointer\n");
 371                 return;
 372         }
 373
 374         pr_debug("Unflattening device tree:\n");
 375         pr_debug("magic: %08x\n", be32_to_cpu(blob->magic));
 376         pr_debug("size: %08x\n", be32_to_cpu(blob->totalsize));
 377         pr_debug("version: %08x\n", be32_to_cpu(blob->version));
 378
 379         if (be32_to_cpu(blob->magic) != OF_DT_HEADER) {
 380                 pr_err("Invalid device tree blob header\n");
 381                 return;
 382         }
 383
 384         /* First pass, scan for size */
 385         start = ((void *)blob) + be32_to_cpu(blob->off_dt_struct);
 386         size = (unsigned long)unflatten_dt_node(blob, 0, &start, NULL, NULL, 0);
 387         size = ALIGN(size, 4);
 388
 389         pr_debug("  size is %lx, allocating...\n", size);
 390
 391         /* Allocate memory for the expanded device tree */
 392         mem = dt_alloc(size + 4, __alignof__(struct device_node));
 393         memset(mem, 0, size);
 394
 395         *(__be32 *)(mem + size) = cpu_to_be32(0xdeadbeef);
 396
 397         pr_debug("  unflattening %p...\n", mem);
 398
 399         /* Second pass, do actual unflattening */
 400         start = ((void *)blob) + be32_to_cpu(blob->off_dt_struct);
 401         unflatten_dt_node(blob, mem, &start, NULL, &allnextp, 0);
 402         if (be32_to_cpup(start) != OF_DT_END)
 403                 pr_warning("Weird tag at end of tree: %08x\n", be32_to_cpup(start));
 404         if (be32_to_cpup(mem + size) != 0xdeadbeef)
 405                 pr_warning("End of tree marker overwritten: %08x\n",
 406                            be32_to_cpup(mem + size));
 407         *allnextp = NULL;
 408
 409         pr_debug(" <- unflatten_device_tree()\n");
 410 }
 411
 412 static void *kernel_tree_alloc(u64 size, u64 align)
 413 {
 414         return kzalloc(size, GFP_KERNEL);
 415 }
 416
 417 /**
 418  * of_fdt_unflatten_tree - create tree of device_nodes from flat blob
 419  *
 420  * unflattens the device-tree passed by the firmware, creating the
 421  * tree of struct device_node. It also fills the "name" and "type"
 422  * pointers of the nodes so the normal device-tree walking functions
 423  * can be used.
 424  */
 425 void of_fdt_unflatten_tree(unsigned long *blob,
 426                         struct device_node **mynodes)
 427 {
 428         struct boot_param_header *device_tree =
 429                 (struct boot_param_header *)blob;
 430         __unflatten_device_tree(device_tree, mynodes, &kernel_tree_alloc);
 431 }
 432 EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree);
 433
 434 /* Everything below here references initial_boot_params directly. */
 435 int __initdata dt_root_addr_cells;
 436 int __initdata dt_root_size_cells;
 437
 438 struct boot_param_header *initial_boot_params;
 439
 440 #ifdef CONFIG_OF_EARLY_FLATTREE
 441
 442 /**
 443  * of_scan_flat_dt - scan flattened tree blob and call callback on each.
 444  * @it: callback function
 445  * @data: context data pointer
 446  *
 447  * This function is used to scan the flattened device-tree, it is
 448  * used to extract the memory information at boot before we can
 449  * unflatten the tree
 450  */
 451 int __init of_scan_flat_dt(int (*it)(unsigned long node,
 452                                      const char *uname, int depth,
 453                                      void *data),
 454                            void *data)
 455 {
 456         unsigned long p = ((unsigned long)initial_boot_params) +
 457                 be32_to_cpu(initial_boot_params->off_dt_struct);
 458         int rc = 0;
 459         int depth = -1;
 460
 461         do {
 462                 u32 tag = be32_to_cpup((__be32 *)p);
 463                 const char *pathp;
 464
 465                 p += 4;
 466                 if (tag == OF_DT_END_NODE) {
 467                         depth--;
 468                         continue;
 469                 }
 470                 if (tag == OF_DT_NOP)
 471                         continue;
 472                 if (tag == OF_DT_END)
 473                         break;
 474                 if (tag == OF_DT_PROP) {
 475                         u32 sz = be32_to_cpup((__be32 *)p);
 476                         p += 8;
 477                         if (be32_to_cpu(initial_boot_params->version) < 0x10)
 478                                 p = ALIGN(p, sz >= 8 ? 8 : 4);
 479                         p += sz;
 480                         p = ALIGN(p, 4);
 481                         continue;
 482                 }
 483                 if (tag != OF_DT_BEGIN_NODE) {
 484                         pr_err("Invalid tag %x in flat device tree!\n", tag);
 485                         return -EINVAL;
 486                 }
 487                 depth++;
 488                 pathp = (char *)p;
 489                 p = ALIGN(p + strlen(pathp) + 1, 4);
 490                 if (*pathp == '/')
 491                         pathp = kbasename(pathp);
 492                 rc = it(p, pathp, depth, data);
 493                 if (rc != 0)
 494                         break;
 495         } while (1);
 496
 497         return rc;
 498 }
 499
 500 /**
 501  * of_get_flat_dt_root - find the root node in the flat blob
 502  */
 503 unsigned long __init of_get_flat_dt_root(void)
 504 {
 505         unsigned long p = ((unsigned long)initial_boot_params) +
 506                 be32_to_cpu(initial_boot_params->off_dt_struct);
 507
 508         while (be32_to_cpup((__be32 *)p) == OF_DT_NOP)
 509                 p += 4;
 510         BUG_ON(be32_to_cpup((__be32 *)p) != OF_DT_BEGIN_NODE);
 511         p += 4;
 512         return ALIGN(p + strlen((char *)p) + 1, 4);
 513 }
 514
 515 /**
 516  * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
 517  *
 518  * This function can be used within scan_flattened_dt callback to get
 519  * access to properties
 520  */
 521 void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
 522                                  unsigned long *size)
 523 {
 524         return of_fdt_get_property(initial_boot_params, node, name, size);
 525 }
 526
 527 /**
 528  * of_flat_dt_is_compatible - Return true if given node has compat in compatible list
 529  * @node: node to test
 530  * @compat: compatible string to compare with compatible list.
 531  */
 532 int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
 533 {
 534         return of_fdt_is_compatible(initial_boot_params, node, compat);
 535 }
 536
 537 /**
 538  * of_flat_dt_match - Return true if node matches a list of compatible values
 539  */
 540 int __init of_flat_dt_match(unsigned long node, const char *const *compat)
 541 {
 542         return of_fdt_match(initial_boot_params, node, compat);
 543 }
 544
 545 struct fdt_scan_status {
 546         const char *name;
 547         int namelen;
 548         int depth;
 549         int found;
 550         int (*iterator)(unsigned long node, const char *uname, int depth, void *data);
 551         void *data;
 552 };
 553
 554 /**
 555  * fdt_scan_node_by_path - iterator for of_scan_flat_dt_by_path function
 556  */
 557 static int __init fdt_scan_node_by_path(unsigned long node, const char *uname,
 558                                         int depth, void *data)
 559 {
 560         struct fdt_scan_status *st = data;
 561
 562         /*
 563          * if scan at the requested fdt node has been completed,
 564          * return -ENXIO to abort further scanning
 565          */
 566         if (depth <= st->depth)
 567                 return -ENXIO;
 568
 569         /* requested fdt node has been found, so call iterator function */
 570         if (st->found)
 571                 return st->iterator(node, uname, depth, st->data);
 572
 573         /* check if scanning automata is entering next level of fdt nodes */
 574         if (depth == st->depth + 1 &&
 575             strncmp(st->name, uname, st->namelen) == 0 &&
 576             uname[st->namelen] == 0) {
 577                 st->depth += 1;
 578                 if (st->name[st->namelen] == 0) {
 579                         st->found = 1;
 580                 } else {
 581                         const char *next = st->name + st->namelen + 1;
 582                         st->name = next;
 583                         st->namelen = strcspn(next, "/");
 584                 }
 585                 return 0;
 586         }
 587
 588         /* scan next fdt node */
 589         return 0;
 590 }
 591
 592 /**
 593  * of_scan_flat_dt_by_path - scan flattened tree blob and call callback on each
 594  *                           child of the given path.
 595  * @path: path to start searching for children
 596  * @it: callback function
 597  * @data: context data pointer
 598  *
 599  * This function is used to scan the flattened device-tree starting from the
 600  * node given by path. It is used to extract information (like reserved
 601  * memory), which is required on ealy boot before we can unflatten the tree.
 602  */
 603 int __init of_scan_flat_dt_by_path(const char *path,
 604         int (*it)(unsigned long node, const char *name, int depth, void *data),
 605         void *data)
 606 {
 607         struct fdt_scan_status st = {path, 0, -1, 0, it, data};
 608         int ret = 0;
 609
 610         if (initial_boot_params)
 611                 ret = of_scan_flat_dt(fdt_scan_node_by_path, &st);
 612
 613         if (!st.found)
 614                 return -ENOENT;
 615         else if (ret == -ENXIO) /* scan has been completed */
 616                 return 0;
 617         else
 618                 return ret;
 619 }
 620
 621 const char * __init of_flat_dt_get_machine_name(void)
 622 {
 623         const char *name;
 624         unsigned long dt_root = of_get_flat_dt_root();
 625
 626         name = of_get_flat_dt_prop(dt_root, "model", NULL);
 627         if (!name)
 628                 name = of_get_flat_dt_prop(dt_root, "compatible", NULL);
 629         return name;
 630 }
 631
 632 /**
 633  * of_flat_dt_match_machine - Iterate match tables to find matching machine.
 634  *
 635  * @default_match: A machine specific ptr to return in case of no match.
 636  * @get_next_compat: callback function to return next compatible match table.
 637  *
 638  * Iterate through machine match tables to find the best match for the machine
 639  * compatible string in the FDT.
 640  */
 641 const void * __init of_flat_dt_match_machine(const void *default_match,
 642                 const void * (*get_next_compat)(const char * const**))
 643 {
 644         const void *data = NULL;
 645         const void *best_data = default_match;
 646         const char *const *compat;
 647         unsigned long dt_root;
 648         unsigned int best_score = ~1, score = 0;
 649
 650         dt_root = of_get_flat_dt_root();
 651         while ((data = get_next_compat(&compat))) {
 652                 score = of_flat_dt_match(dt_root, compat);
 653                 if (score > 0 && score < best_score) {
 654                         best_data = data;
 655                         best_score = score;
 656                 }
 657         }
 658         if (!best_data) {
 659                 const char *prop;
 660                 long size;
 661
 662                 pr_err("\n unrecognized device tree list:\n[ ");
 663
 664                 prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
 665                 if (prop) {
 666                         while (size > 0) {
 667                                 printk("'%s' ", prop);
 668                                 size -= strlen(prop) + 1;
 669                                 prop += strlen(prop) + 1;
 670                         }
 671                 }
 672                 printk("]\n\n");
 673                 return NULL;
 674         }
 675
 676         pr_info("Machine model: %s\n", of_flat_dt_get_machine_name());
 677
 678         return best_data;
 679 }
 680
 681 #ifdef CONFIG_BLK_DEV_INITRD
 682 /**
 683  * early_init_dt_check_for_initrd - Decode initrd location from flat tree
 684  * @node: reference to node containing initrd location ('chosen')
 685  */
 686 static void __init early_init_dt_check_for_initrd(unsigned long node)
 687 {
 688         u64 start, end;
 689         unsigned long len;
 690         __be32 *prop;
 691
 692         pr_debug("Looking for initrd properties... ");
 693
 694         prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);
 695         if (!prop)
 696                 return;
 697         start = of_read_number(prop, len/4);
 698
 699         prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
 700         if (!prop)
 701                 return;
 702         end = of_read_number(prop, len/4);
 703
 704         initrd_start = (unsigned long)__va(start);
 705         initrd_end = (unsigned long)__va(end);
 706         initrd_below_start_ok = 1;
 707
 708         pr_debug("initrd_start=0x%llx  initrd_end=0x%llx\n",
 709                  (unsigned long long)start, (unsigned long long)end);
 710 }
 711 #else
 712 static inline void early_init_dt_check_for_initrd(unsigned long node)
 713 {
 714 }
 715 #endif /* CONFIG_BLK_DEV_INITRD */
 716
 717 /**
 718  * early_init_dt_scan_root - fetch the top level address and size cells
 719  */
 720 int __init early_init_dt_scan_root(unsigned long node, const char *uname,
 721                                    int depth, void *data)
 722 {
 723         __be32 *prop;
 724
 725         if (depth != 0)
 726                 return 0;
 727
 728         dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
 729         dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
 730
 731         prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
 732         if (prop)
 733                 dt_root_size_cells = be32_to_cpup(prop);
 734         pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells);
 735
 736         prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
 737         if (prop)
 738                 dt_root_addr_cells = be32_to_cpup(prop);
 739         pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells);
 740
 741         /* break now */
 742         return 1;
 743 }
 744
 745 u64 __init dt_mem_next_cell(int s, __be32 **cellp)
 746 {
 747         __be32 *p = *cellp;
 748
 749         *cellp = p + s;
 750         return of_read_number(p, s);
 751 }
 752
 753 /**
 754  * early_init_dt_scan_memory - Look for an parse memory nodes
 755  */
 756 int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
 757                                      int depth, void *data)
 758 {
 759         char *type = of_get_flat_dt_prop(node, "device_type", NULL);
 760         __be32 *reg, *endp;
 761         unsigned long l;
 762
 763         /* We are scanning "memory" nodes only */
 764         if (type == NULL) {
 765                 /*
 766                  * The longtrail doesn't have a device_type on the
 767                  * /memory node, so look for the node called /memory@0.
 768                  */
 769                 if (depth != 1 || strcmp(uname, "memory@0") != 0)
 770                         return 0;
 771         } else if (strcmp(type, "memory") != 0)
 772                 return 0;
 773
 774         reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
 775         if (reg == NULL)
 776                 reg = of_get_flat_dt_prop(node, "reg", &l);
 777         if (reg == NULL)
 778                 return 0;
 779
 780         endp = reg + (l / sizeof(__be32));
 781
 782         pr_debug("memory scan node %s, reg size %ld, data: %x %x %x %x,\n",
 783             uname, l, reg[0], reg[1], reg[2], reg[3]);
 784
 785         while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
 786                 u64 base, size;
 787
 788                 base = dt_mem_next_cell(dt_root_addr_cells, &reg);
 789                 size = dt_mem_next_cell(dt_root_size_cells, &reg);
 790
 791                 if (size == 0)
 792                         continue;
 793                 pr_debug(" - %llx ,  %llx\n", (unsigned long long)base,
 794                     (unsigned long long)size);
 795
 796                 early_init_dt_add_memory_arch(base, size);
 797         }
 798
 799         return 0;
 800 }
 801
 802 int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
 803                                      int depth, void *data)
 804 {
 805         unsigned long l;
 806         char *p;
 807
 808         pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname);
 809
 810         if (depth != 1 || !data ||
 811             (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
 812                 return 0;
 813
 814         early_init_dt_check_for_initrd(node);
 815
 816         /* Retrieve command line */
 817         p = of_get_flat_dt_prop(node, "bootargs", &l);
 818         if (p != NULL && l > 0)
 819                 strlcpy(data, p, min((int)l, COMMAND_LINE_SIZE));
 820
 821         /*
 822          * CONFIG_CMDLINE is meant to be a default in case nothing else
 823          * managed to set the command line, unless CONFIG_CMDLINE_FORCE
 824          * is set in which case we override whatever was found earlier.
 825          */
 826 #ifdef CONFIG_CMDLINE
 827 #ifndef CONFIG_CMDLINE_FORCE
 828         if (!((char *)data)[0])
 829 #endif
 830                 strlcpy(data, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 831 #endif /* CONFIG_CMDLINE */
 832
 833         pr_debug("Command line is: %s\n", (char*)data);
 834
 835         /* break now */
 836         return 1;
 837 }
 838
 839 #ifdef CONFIG_HAVE_MEMBLOCK
 840 void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
 841 {
 842         const u64 phys_offset = __pa(PAGE_OFFSET);
 843         base &= PAGE_MASK;
 844         size &= PAGE_MASK;
 845         if (base + size < phys_offset) {
 846                 pr_warning("Ignoring memory block 0x%llx - 0x%llx\n",
 847                            base, base + size);
 848                 return;
 849         }
 850         if (base < phys_offset) {
 851                 pr_warning("Ignoring memory range 0x%llx - 0x%llx\n",
 852                            base, phys_offset);
 853                 size -= phys_offset - base;
 854                 base = phys_offset;
 855         }
 856         memblock_add(base, size);
 857 }
 858
 859 /*
 860  * called from unflatten_device_tree() to bootstrap devicetree itself
 861  * Architectures can override this definition if memblock isn't used
 862  */
 863 void * __init __weak early_init_dt_alloc_memory_arch(u64 size, u64 align)
 864 {
 865         return __va(memblock_alloc(size, align));
 866 }
 867 #endif
 868
 869 bool __init early_init_dt_scan(void *params)
 870 {
 871         if (!params)
 872                 return false;
 873
 874         /* Setup flat device-tree pointer */
 875         initial_boot_params = params;
 876
 877         /* check device tree validity */
 878         if (be32_to_cpu(initial_boot_params->magic) != OF_DT_HEADER) {
 879                 initial_boot_params = NULL;
 880                 return false;
 881         }
 882
 883         /* Retrieve various information from the /chosen node */
 884         of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line);
 885
 886         /* Initialize {size,address}-cells info */
 887         of_scan_flat_dt(early_init_dt_scan_root, NULL);
 888
 889         /* Setup memory, calling early_init_dt_add_memory_arch */
 890         of_scan_flat_dt(early_init_dt_scan_memory, NULL);
 891
 892         return true;
 893 }
 894
 895 /**
 896  * unflatten_device_tree - create tree of device_nodes from flat blob
 897  *
 898  * unflattens the device-tree passed by the firmware, creating the
 899  * tree of struct device_node. It also fills the "name" and "type"
 900  * pointers of the nodes so the normal device-tree walking functions
 901  * can be used.
 902  */
 903 void __init unflatten_device_tree(void)
 904 {
 905         __unflatten_device_tree(initial_boot_params, &of_allnodes,
 906                                 early_init_dt_alloc_memory_arch);
 907
 908         /* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */
 909         of_alias_scan(early_init_dt_alloc_memory_arch);
 910 }
 911
 912 /**
 913  * unflatten_and_copy_device_tree - copy and create tree of device_nodes from flat blob
 914  *
 915  * Copies and unflattens the device-tree passed by the firmware, creating the
 916  * tree of struct device_node. It also fills the "name" and "type"
 917  * pointers of the nodes so the normal device-tree walking functions
 918  * can be used. This should only be used when the FDT memory has not been
 919  * reserved such is the case when the FDT is built-in to the kernel init
 920  * section. If the FDT memory is reserved already then unflatten_device_tree
 921  * should be used instead.
 922  */
 923 void __init unflatten_and_copy_device_tree(void)
 924 {
 925         int size;
 926         void *dt;
 927
 928         if (!initial_boot_params) {
 929                 pr_warn("No valid device tree found, continuing without\n");
 930                 return;
 931         }
 932
 933         size = __be32_to_cpu(initial_boot_params->totalsize);
 934         dt = early_init_dt_alloc_memory_arch(size,
 935                 __alignof__(struct boot_param_header));
 936
 937         if (dt) {
 938                 memcpy(dt, initial_boot_params, size);
 939                 initial_boot_params = dt;
 940         }
 941         unflatten_device_tree();
 942 }
 943
 944 #endif /* CONFIG_OF_EARLY_FLATTREE */