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#include <asm/setup.h> /* for COMMAND_LINE_SIZE */ 22#ifdef CONFIG_PPC 23#include <asm/machdep.h> 24#endif /* CONFIG_PPC */ 25 26#include <asm/page.h> 27 28char *of_fdt_get_string(struct boot_param_header *blob, u32 offset) 29{ 30 return ((char *)blob) + 31 be32_to_cpu(blob->off_dt_strings) + offset; 32} 33 34/** 35 * of_fdt_get_property - Given a node in the given flat blob, return 36 * the property ptr 37 */ 38void *of_fdt_get_property(struct boot_param_header *blob, 39 unsigned long node, const char *name, 40 unsigned long *size) 41{ 42 unsigned long p = node; 43 44 do { 45 u32 tag = be32_to_cpup((__be32 *)p); 46 u32 sz, noff; 47 const char *nstr; 48 49 p += 4; 50 if (tag == OF_DT_NOP) 51 continue; 52 if (tag != OF_DT_PROP) 53 return NULL; 54 55 sz = be32_to_cpup((__be32 *)p); 56 noff = be32_to_cpup((__be32 *)(p + 4)); 57 p += 8; 58 if (be32_to_cpu(blob->version) < 0x10) 59 p = ALIGN(p, sz >= 8 ? 8 : 4); 60 61 nstr = of_fdt_get_string(blob, noff); 62 if (nstr == NULL) { 63 pr_warning("Can't find property index name !\n"); 64 return NULL; 65 } 66 if (strcmp(name, nstr) == 0) { 67 if (size) 68 *size = sz; 69 return (void *)p; 70 } 71 p += sz; 72 p = ALIGN(p, 4); 73 } while (1); 74} 75 76/** 77 * of_fdt_is_compatible - Return true if given node from the given blob has 78 * compat in its compatible list 79 * @blob: A device tree blob 80 * @node: node to test 81 * @compat: compatible string to compare with compatible list. 82 * 83 * On match, returns a non-zero value with smaller values returned for more 84 * specific compatible values. 85 */ 86int of_fdt_is_compatible(struct boot_param_header *blob, 87 unsigned long node, const char *compat) 88{ 89 const char *cp; 90 unsigned long cplen, l, score = 0; 91 92 cp = of_fdt_get_property(blob, node, "compatible", &cplen); 93 if (cp == NULL) 94 return 0; 95 while (cplen > 0) { 96 score++; 97 if (of_compat_cmp(cp, compat, strlen(compat)) == 0) 98 return score; 99 l = strlen(cp) + 1; 100 cp += l; 101 cplen -= l; 102 } 103 104 return 0; 105} 106 107/** 108 * of_fdt_match - Return true if node matches a list of compatible values 109 */ 110int of_fdt_match(struct boot_param_header *blob, unsigned long node, 111 const char *const *compat) 112{ 113 unsigned int tmp, score = 0; 114 115 if (!compat) 116 return 0; 117 118 while (*compat) { 119 tmp = of_fdt_is_compatible(blob, node, *compat); 120 if (tmp && (score == 0 || (tmp < score))) 121 score = tmp; 122 compat++; 123 } 124 125 return score; 126} 127 128static void *unflatten_dt_alloc(unsigned long *mem, unsigned long size, 129 unsigned long align) 130{ 131 void *res; 132 133 *mem = ALIGN(*mem, align); 134 res = (void *)*mem; 135 *mem += size; 136 137 return res; 138} 139 140/** 141 * unflatten_dt_node - Alloc and populate a device_node from the flat tree 142 * @blob: The parent device tree blob 143 * @mem: Memory chunk to use for allocating device nodes and properties 144 * @p: pointer to node in flat tree 145 * @dad: Parent struct device_node 146 * @allnextpp: pointer to ->allnext from last allocated device_node 147 * @fpsize: Size of the node path up at the current depth. 148 */ 149static unsigned long unflatten_dt_node(struct boot_param_header *blob, 150 unsigned long mem, 151 unsigned long *p, 152 struct device_node *dad, 153 struct device_node ***allnextpp, 154 unsigned long fpsize) 155{ 156 struct device_node *np; 157 struct property *pp, **prev_pp = NULL; 158 char *pathp; 159 u32 tag; 160 unsigned int l, allocl; 161 int has_name = 0; 162 int new_format = 0; 163 164 tag = be32_to_cpup((__be32 *)(*p)); 165 if (tag != OF_DT_BEGIN_NODE) { 166 pr_err("Weird tag at start of node: %x\n", tag); 167 return mem; 168 } 169 *p += 4; 170 pathp = (char *)*p; 171 l = allocl = strlen(pathp) + 1; 172 *p = ALIGN(*p + l, 4); 173 174 /* version 0x10 has a more compact unit name here instead of the full 175 * path. we accumulate the full path size using "fpsize", we'll rebuild 176 * it later. We detect this because the first character of the name is 177 * not '/'. 178 */ 179 if ((*pathp) != '/') { 180 new_format = 1; 181 if (fpsize == 0) { 182 /* root node: special case. fpsize accounts for path 183 * plus terminating zero. root node only has '/', so 184 * fpsize should be 2, but we want to avoid the first 185 * level nodes to have two '/' so we use fpsize 1 here 186 */ 187 fpsize = 1; 188 allocl = 2; 189 } else { 190 /* account for '/' and path size minus terminal 0 191 * already in 'l' 192 */ 193 fpsize += l; 194 allocl = fpsize; 195 } 196 } 197 198 np = unflatten_dt_alloc(&mem, sizeof(struct device_node) + allocl, 199 __alignof__(struct device_node)); 200 if (allnextpp) { 201 memset(np, 0, sizeof(*np)); 202 np->full_name = ((char *)np) + sizeof(struct device_node); 203 if (new_format) { 204 char *fn = np->full_name; 205 /* rebuild full path for new format */ 206 if (dad && dad->parent) { 207 strcpy(fn, dad->full_name); 208#ifdef DEBUG 209 if ((strlen(fn) + l + 1) != allocl) { 210 pr_debug("%s: p: %d, l: %d, a: %d\n", 211 pathp, (int)strlen(fn), 212 l, allocl); 213 } 214#endif 215 fn += strlen(fn); 216 } 217 *(fn++) = '/'; 218 memcpy(fn, pathp, l); 219 } else 220 memcpy(np->full_name, pathp, l); 221 prev_pp = &np->properties; 222 **allnextpp = np; 223 *allnextpp = &np->allnext; 224 if (dad != NULL) { 225 np->parent = dad; 226 /* we temporarily use the next field as `last_child'*/ 227 if (dad->next == NULL) 228 dad->child = np; 229 else 230 dad->next->sibling = np; 231 dad->next = np; 232 } 233 kref_init(&np->kref); 234 } 235 /* process properties */ 236 while (1) { 237 u32 sz, noff; 238 char *pname; 239 240 tag = be32_to_cpup((__be32 *)(*p)); 241 if (tag == OF_DT_NOP) { 242 *p += 4; 243 continue; 244 } 245 if (tag != OF_DT_PROP) 246 break; 247 *p += 4; 248 sz = be32_to_cpup((__be32 *)(*p)); 249 noff = be32_to_cpup((__be32 *)((*p) + 4)); 250 *p += 8; 251 if (be32_to_cpu(blob->version) < 0x10) 252 *p = ALIGN(*p, sz >= 8 ? 8 : 4); 253 254 pname = of_fdt_get_string(blob, noff); 255 if (pname == NULL) { 256 pr_info("Can't find property name in list !\n"); 257 break; 258 } 259 if (strcmp(pname, "name") == 0) 260 has_name = 1; 261 l = strlen(pname) + 1; 262 pp = unflatten_dt_alloc(&mem, sizeof(struct property), 263 __alignof__(struct property)); 264 if (allnextpp) { 265 /* We accept flattened tree phandles either in 266 * ePAPR-style "phandle" properties, or the 267 * legacy "linux,phandle" properties. If both 268 * appear and have different values, things 269 * will get weird. Don't do that. */ 270 if ((strcmp(pname, "phandle") == 0) || 271 (strcmp(pname, "linux,phandle") == 0)) { 272 if (np->phandle == 0) 273 np->phandle = be32_to_cpup((__be32*)*p); 274 } 275 /* And we process the "ibm,phandle" property 276 * used in pSeries dynamic device tree 277 * stuff */ 278 if (strcmp(pname, "ibm,phandle") == 0) 279 np->phandle = be32_to_cpup((__be32 *)*p); 280 pp->name = pname; 281 pp->length = sz; 282 pp->value = (void *)*p; 283 *prev_pp = pp; 284 prev_pp = &pp->next; 285 } 286 *p = ALIGN((*p) + sz, 4); 287 } 288 /* with version 0x10 we may not have the name property, recreate 289 * it here from the unit name if absent 290 */ 291 if (!has_name) { 292 char *p1 = pathp, *ps = pathp, *pa = NULL; 293 int sz; 294 295 while (*p1) { 296 if ((*p1) == '@') 297 pa = p1; 298 if ((*p1) == '/') 299 ps = p1 + 1; 300 p1++; 301 } 302 if (pa < ps) 303 pa = p1; 304 sz = (pa - ps) + 1; 305 pp = unflatten_dt_alloc(&mem, sizeof(struct property) + sz, 306 __alignof__(struct property)); 307 if (allnextpp) { 308 pp->name = "name"; 309 pp->length = sz; 310 pp->value = pp + 1; 311 *prev_pp = pp; 312 prev_pp = &pp->next; 313 memcpy(pp->value, ps, sz - 1); 314 ((char *)pp->value)[sz - 1] = 0; 315 pr_debug("fixed up name for %s -> %s\n", pathp, 316 (char *)pp->value); 317 } 318 } 319 if (allnextpp) { 320 *prev_pp = NULL; 321 np->name = of_get_property(np, "name", NULL); 322 np->type = of_get_property(np, "device_type", NULL); 323 324 if (!np->name) 325 np->name = "<NULL>"; 326 if (!np->type) 327 np->type = "<NULL>"; 328 } 329 while (tag == OF_DT_BEGIN_NODE || tag == OF_DT_NOP) { 330 if (tag == OF_DT_NOP) 331 *p += 4; 332 else 333 mem = unflatten_dt_node(blob, mem, p, np, allnextpp, 334 fpsize); 335 tag = be32_to_cpup((__be32 *)(*p)); 336 } 337 if (tag != OF_DT_END_NODE) { 338 pr_err("Weird tag at end of node: %x\n", tag); 339 return mem; 340 } 341 *p += 4; 342 return mem; 343} 344 345/** 346 * __unflatten_device_tree - create tree of device_nodes from flat blob 347 * 348 * unflattens a device-tree, creating the 349 * tree of struct device_node. It also fills the "name" and "type" 350 * pointers of the nodes so the normal device-tree walking functions 351 * can be used. 352 * @blob: The blob to expand 353 * @mynodes: The device_node tree created by the call 354 * @dt_alloc: An allocator that provides a virtual address to memory 355 * for the resulting tree 356 */ 357static void __unflatten_device_tree(struct boot_param_header *blob, 358 struct device_node **mynodes, 359 void * (*dt_alloc)(u64 size, u64 align)) 360{ 361 unsigned long start, mem, size; 362 struct device_node **allnextp = mynodes; 363 364 pr_debug(" -> unflatten_device_tree()\n"); 365 366 if (!blob) { 367 pr_debug("No device tree pointer\n"); 368 return; 369 } 370 371 pr_debug("Unflattening device tree:\n"); 372 pr_debug("magic: %08x\n", be32_to_cpu(blob->magic)); 373 pr_debug("size: %08x\n", be32_to_cpu(blob->totalsize)); 374 pr_debug("version: %08x\n", be32_to_cpu(blob->version)); 375 376 if (be32_to_cpu(blob->magic) != OF_DT_HEADER) { 377 pr_err("Invalid device tree blob header\n"); 378 return; 379 } 380 381 /* First pass, scan for size */ 382 start = ((unsigned long)blob) + 383 be32_to_cpu(blob->off_dt_struct); 384 size = unflatten_dt_node(blob, 0, &start, NULL, NULL, 0); 385 size = (size | 3) + 1; 386 387 pr_debug(" size is %lx, allocating...\n", size); 388 389 /* Allocate memory for the expanded device tree */ 390 mem = (unsigned long) 391 dt_alloc(size + 4, __alignof__(struct device_node)); 392 393 ((__be32 *)mem)[size / 4] = cpu_to_be32(0xdeadbeef); 394 395 pr_debug(" unflattening %lx...\n", mem); 396 397 /* Second pass, do actual unflattening */ 398 start = ((unsigned long)blob) + 399 be32_to_cpu(blob->off_dt_struct); 400 unflatten_dt_node(blob, mem, &start, NULL, &allnextp, 0); 401 if (be32_to_cpup((__be32 *)start) != OF_DT_END) 402 pr_warning("Weird tag at end of tree: %08x\n", *((u32 *)start)); 403 if (be32_to_cpu(((__be32 *)mem)[size / 4]) != 0xdeadbeef) 404 pr_warning("End of tree marker overwritten: %08x\n", 405 be32_to_cpu(((__be32 *)mem)[size / 4])); 406 *allnextp = NULL; 407 408 pr_debug(" <- unflatten_device_tree()\n"); 409} 410 411static void *kernel_tree_alloc(u64 size, u64 align) 412{ 413 return kzalloc(size, GFP_KERNEL); 414} 415 416/** 417 * of_fdt_unflatten_tree - create tree of device_nodes from flat blob 418 * 419 * unflattens the device-tree passed by the firmware, creating the 420 * tree of struct device_node. It also fills the "name" and "type" 421 * pointers of the nodes so the normal device-tree walking functions 422 * can be used. 423 */ 424void of_fdt_unflatten_tree(unsigned long *blob, 425 struct device_node **mynodes) 426{ 427 struct boot_param_header *device_tree = 428 (struct boot_param_header *)blob; 429 __unflatten_device_tree(device_tree, mynodes, &kernel_tree_alloc); 430} 431EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree); 432 433/* Everything below here references initial_boot_params directly. */ 434int __initdata dt_root_addr_cells; 435int __initdata dt_root_size_cells; 436 437struct boot_param_header *initial_boot_params; 438 439#ifdef CONFIG_OF_EARLY_FLATTREE 440 441/** 442 * of_scan_flat_dt - scan flattened tree blob and call callback on each. 443 * @it: callback function 444 * @data: context data pointer 445 * 446 * This function is used to scan the flattened device-tree, it is 447 * used to extract the memory information at boot before we can 448 * unflatten the tree 449 */ 450int __init of_scan_flat_dt(int (*it)(unsigned long node, 451 const char *uname, int depth, 452 void *data), 453 void *data) 454{ 455 unsigned long p = ((unsigned long)initial_boot_params) + 456 be32_to_cpu(initial_boot_params->off_dt_struct); 457 int rc = 0; 458 int depth = -1; 459 460 do { 461 u32 tag = be32_to_cpup((__be32 *)p); 462 char *pathp; 463 464 p += 4; 465 if (tag == OF_DT_END_NODE) { 466 depth--; 467 continue; 468 } 469 if (tag == OF_DT_NOP) 470 continue; 471 if (tag == OF_DT_END) 472 break; 473 if (tag == OF_DT_PROP) { 474 u32 sz = be32_to_cpup((__be32 *)p); 475 p += 8; 476 if (be32_to_cpu(initial_boot_params->version) < 0x10) 477 p = ALIGN(p, sz >= 8 ? 8 : 4); 478 p += sz; 479 p = ALIGN(p, 4); 480 continue; 481 } 482 if (tag != OF_DT_BEGIN_NODE) { 483 pr_err("Invalid tag %x in flat device tree!\n", tag); 484 return -EINVAL; 485 } 486 depth++; 487 pathp = (char *)p; 488 p = ALIGN(p + strlen(pathp) + 1, 4); 489 if ((*pathp) == '/') { 490 char *lp, *np; 491 for (lp = NULL, np = pathp; *np; np++) 492 if ((*np) == '/') 493 lp = np+1; 494 if (lp != NULL) 495 pathp = lp; 496 } 497 rc = it(p, pathp, depth, data); 498 if (rc != 0) 499 break; 500 } while (1); 501 502 return rc; 503} 504 505/** 506 * of_get_flat_dt_root - find the root node in the flat blob 507 */ 508unsigned long __init of_get_flat_dt_root(void) 509{ 510 unsigned long p = ((unsigned long)initial_boot_params) + 511 be32_to_cpu(initial_boot_params->off_dt_struct); 512 513 while (be32_to_cpup((__be32 *)p) == OF_DT_NOP) 514 p += 4; 515 BUG_ON(be32_to_cpup((__be32 *)p) != OF_DT_BEGIN_NODE); 516 p += 4; 517 return ALIGN(p + strlen((char *)p) + 1, 4); 518} 519 520/** 521 * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr 522 * 523 * This function can be used within scan_flattened_dt callback to get 524 * access to properties 525 */ 526void *__init of_get_flat_dt_prop(unsigned long node, const char *name, 527 unsigned long *size) 528{ 529 return of_fdt_get_property(initial_boot_params, node, name, size); 530} 531 532/** 533 * of_flat_dt_is_compatible - Return true if given node has compat in compatible list 534 * @node: node to test 535 * @compat: compatible string to compare with compatible list. 536 */ 537int __init of_flat_dt_is_compatible(unsigned long node, const char *compat) 538{ 539 return of_fdt_is_compatible(initial_boot_params, node, compat); 540} 541 542/** 543 * of_flat_dt_match - Return true if node matches a list of compatible values 544 */ 545int __init of_flat_dt_match(unsigned long node, const char *const *compat) 546{ 547 return of_fdt_match(initial_boot_params, node, compat); 548} 549 550#ifdef CONFIG_BLK_DEV_INITRD 551/** 552 * early_init_dt_check_for_initrd - Decode initrd location from flat tree 553 * @node: reference to node containing initrd location ('chosen') 554 */ 555void __init early_init_dt_check_for_initrd(unsigned long node) 556{ 557 unsigned long start, end, len; 558 __be32 *prop; 559 560 pr_debug("Looking for initrd properties... "); 561 562 prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len); 563 if (!prop) 564 return; 565 start = of_read_ulong(prop, len/4); 566 567 prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len); 568 if (!prop) 569 return; 570 end = of_read_ulong(prop, len/4); 571 572 early_init_dt_setup_initrd_arch(start, end); 573 pr_debug("initrd_start=0x%lx initrd_end=0x%lx\n", start, end); 574} 575#else 576inline void early_init_dt_check_for_initrd(unsigned long node) 577{ 578} 579#endif /* CONFIG_BLK_DEV_INITRD */ 580 581/** 582 * early_init_dt_scan_root - fetch the top level address and size cells 583 */ 584int __init early_init_dt_scan_root(unsigned long node, const char *uname, 585 int depth, void *data) 586{ 587 __be32 *prop; 588 589 if (depth != 0) 590 return 0; 591 592 dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT; 593 dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT; 594 595 prop = of_get_flat_dt_prop(node, "#size-cells", NULL); 596 if (prop) 597 dt_root_size_cells = be32_to_cpup(prop); 598 pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells); 599 600 prop = of_get_flat_dt_prop(node, "#address-cells", NULL); 601 if (prop) 602 dt_root_addr_cells = be32_to_cpup(prop); 603 pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells); 604 605 /* break now */ 606 return 1; 607} 608 609u64 __init dt_mem_next_cell(int s, __be32 **cellp) 610{ 611 __be32 *p = *cellp; 612 613 *cellp = p + s; 614 return of_read_number(p, s); 615} 616 617/** 618 * early_init_dt_scan_memory - Look for an parse memory nodes 619 */ 620int __init early_init_dt_scan_memory(unsigned long node, const char *uname, 621 int depth, void *data) 622{ 623 char *type = of_get_flat_dt_prop(node, "device_type", NULL); 624 __be32 *reg, *endp; 625 unsigned long l; 626 627 /* We are scanning "memory" nodes only */ 628 if (type == NULL) { 629 /* 630 * The longtrail doesn't have a device_type on the 631 * /memory node, so look for the node called /memory@0. 632 */ 633 if (depth != 1 || strcmp(uname, "memory@0") != 0) 634 return 0; 635 } else if (strcmp(type, "memory") != 0) 636 return 0; 637 638 reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l); 639 if (reg == NULL) 640 reg = of_get_flat_dt_prop(node, "reg", &l); 641 if (reg == NULL) 642 return 0; 643 644 endp = reg + (l / sizeof(__be32)); 645 646 pr_debug("memory scan node %s, reg size %ld, data: %x %x %x %x,\n", 647 uname, l, reg[0], reg[1], reg[2], reg[3]); 648 649 while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) { 650 u64 base, size; 651 652 base = dt_mem_next_cell(dt_root_addr_cells, ®); 653 size = dt_mem_next_cell(dt_root_size_cells, ®); 654 655 if (size == 0) 656 continue; 657 pr_debug(" - %llx , %llx\n", (unsigned long long)base, 658 (unsigned long long)size); 659 660 early_init_dt_add_memory_arch(base, size); 661 } 662 663 return 0; 664} 665 666int __init early_init_dt_scan_chosen(unsigned long node, const char *uname, 667 int depth, void *data) 668{ 669 unsigned long l; 670 char *p; 671 672 pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname); 673 674 if (depth != 1 || !data || 675 (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0)) 676 return 0; 677 678 early_init_dt_check_for_initrd(node); 679 680 /* Retrieve command line */ 681 p = of_get_flat_dt_prop(node, "bootargs", &l); 682 if (p != NULL && l > 0) 683 strlcpy(data, p, min((int)l, COMMAND_LINE_SIZE)); 684 685 /* 686 * CONFIG_CMDLINE is meant to be a default in case nothing else 687 * managed to set the command line, unless CONFIG_CMDLINE_FORCE 688 * is set in which case we override whatever was found earlier. 689 */ 690#ifdef CONFIG_CMDLINE 691#ifndef CONFIG_CMDLINE_FORCE 692 if (!((char *)data)[0]) 693#endif 694 strlcpy(data, CONFIG_CMDLINE, COMMAND_LINE_SIZE); 695#endif /* CONFIG_CMDLINE */ 696 697 pr_debug("Command line is: %s\n", (char*)data); 698 699 /* break now */ 700 return 1; 701} 702 703/** 704 * unflatten_device_tree - create tree of device_nodes from flat blob 705 * 706 * unflattens the device-tree passed by the firmware, creating the 707 * tree of struct device_node. It also fills the "name" and "type" 708 * pointers of the nodes so the normal device-tree walking functions 709 * can be used. 710 */ 711void __init unflatten_device_tree(void) 712{ 713 __unflatten_device_tree(initial_boot_params, &allnodes, 714 early_init_dt_alloc_memory_arch); 715 716 /* Get pointer to "/chosen" and "/aliasas" nodes for use everywhere */ 717 of_alias_scan(early_init_dt_alloc_memory_arch); 718} 719 720#endif /* CONFIG_OF_EARLY_FLATTREE */ 721