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