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