arch/powerpc/boot/flatdevtree.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License as published by
   4  * the Free Software Foundation; either version 2 of the License, or
   5  * (at your option) any later version.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  *
  12  * You should have received a copy of the GNU General Public License
  13  * along with this program; if not, write to the Free Software
  14  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  15  *
  16  * Copyright Pantelis Antoniou 2006
  17  * Copyright (C) IBM Corporation 2006
  18  *
  19  * Authors: Pantelis Antoniou <pantelis@embeddedalley.com>
  20  *          Hollis Blanchard <hollisb@us.ibm.com>
  21  *          Mark A. Greer <mgreer@mvista.com>
  22  *          Paul Mackerras <paulus@samba.org>
  23  */
  24
  25 #include <string.h>
  26 #include <stddef.h>
  27 #include "flatdevtree.h"
  28 #include "flatdevtree_env.h"
  29
  30 #define _ALIGN(x, al)   (((x) + (al) - 1) & ~((al) - 1))
  31
  32 static char *ft_root_node(struct ft_cxt *cxt)
  33 {
  34         return cxt->rgn[FT_STRUCT].start;
  35 }
  36
  37 /* Routines for keeping node ptrs returned by ft_find_device current */
  38 /* First entry not used b/c it would return 0 and be taken as NULL/error */
  39 static void *ft_get_phandle(struct ft_cxt *cxt, char *node)
  40 {
  41         unsigned int i;
  42
  43         if (!node)
  44                 return NULL;
  45
  46         for (i = 1; i < cxt->nodes_used; i++)   /* already there? */
  47                 if (cxt->node_tbl[i] == node)
  48                         return (void *)i;
  49
  50         if (cxt->nodes_used < cxt->node_max) {
  51                 cxt->node_tbl[cxt->nodes_used] = node;
  52                 return (void *)cxt->nodes_used++;
  53         }
  54
  55         return NULL;
  56 }
  57
  58 static char *ft_node_ph2node(struct ft_cxt *cxt, const void *phandle)
  59 {
  60         unsigned int i = (unsigned int)phandle;
  61
  62         if (i < cxt->nodes_used)
  63                 return cxt->node_tbl[i];
  64         return NULL;
  65 }
  66
  67 static void ft_node_update_before(struct ft_cxt *cxt, char *addr, int shift)
  68 {
  69         unsigned int i;
  70
  71         if (shift == 0)
  72                 return;
  73
  74         for (i = 1; i < cxt->nodes_used; i++)
  75                 if (cxt->node_tbl[i] < addr)
  76                         cxt->node_tbl[i] += shift;
  77 }
  78
  79 static void ft_node_update_after(struct ft_cxt *cxt, char *addr, int shift)
  80 {
  81         unsigned int i;
  82
  83         if (shift == 0)
  84                 return;
  85
  86         for (i = 1; i < cxt->nodes_used; i++)
  87                 if (cxt->node_tbl[i] >= addr)
  88                         cxt->node_tbl[i] += shift;
  89 }
  90
  91 /* Struct used to return info from ft_next() */
  92 struct ft_atom {
  93         u32 tag;
  94         const char *name;
  95         void *data;
  96         u32 size;
  97 };
  98
  99 /* Set ptrs to current one's info; return addr of next one */
 100 static char *ft_next(struct ft_cxt *cxt, char *p, struct ft_atom *ret)
 101 {
 102         u32 sz;
 103
 104         if (p >= cxt->rgn[FT_STRUCT].start + cxt->rgn[FT_STRUCT].size)
 105                 return NULL;
 106
 107         ret->tag = be32_to_cpu(*(u32 *) p);
 108         p += 4;
 109
 110         switch (ret->tag) {     /* Tag */
 111         case OF_DT_BEGIN_NODE:
 112                 ret->name = p;
 113                 ret->data = (void *)(p - 4);    /* start of node */
 114                 p += _ALIGN(strlen(p) + 1, 4);
 115                 break;
 116         case OF_DT_PROP:
 117                 ret->size = sz = be32_to_cpu(*(u32 *) p);
 118                 ret->name = cxt->str_anchor + be32_to_cpu(*(u32 *) (p + 4));
 119                 ret->data = (void *)(p + 8);
 120                 p += 8 + _ALIGN(sz, 4);
 121                 break;
 122         case OF_DT_END_NODE:
 123         case OF_DT_NOP:
 124                 break;
 125         case OF_DT_END:
 126         default:
 127                 p = NULL;
 128                 break;
 129         }
 130
 131         return p;
 132 }
 133
 134 #define HDR_SIZE        _ALIGN(sizeof(struct boot_param_header), 8)
 135 #define EXPAND_INCR     1024    /* alloc this much extra when expanding */
 136
 137 /* See if the regions are in the standard order and non-overlapping */
 138 static int ft_ordered(struct ft_cxt *cxt)
 139 {
 140         char *p = (char *)cxt->bph + HDR_SIZE;
 141         enum ft_rgn_id r;
 142
 143         for (r = FT_RSVMAP; r <= FT_STRINGS; ++r) {
 144                 if (p > cxt->rgn[r].start)
 145                         return 0;
 146                 p = cxt->rgn[r].start + cxt->rgn[r].size;
 147         }
 148         return p <= (char *)cxt->bph + cxt->max_size;
 149 }
 150
 151 /* Copy the tree to a newly-allocated region and put things in order */
 152 static int ft_reorder(struct ft_cxt *cxt, int nextra)
 153 {
 154         unsigned long tot;
 155         enum ft_rgn_id r;
 156         char *p, *pend;
 157         int stroff;
 158
 159         tot = HDR_SIZE + EXPAND_INCR;
 160         for (r = FT_RSVMAP; r <= FT_STRINGS; ++r)
 161                 tot += cxt->rgn[r].size;
 162         if (nextra > 0)
 163                 tot += nextra;
 164         tot = _ALIGN(tot, 8);
 165
 166         if (!cxt->realloc)
 167                 return 0;
 168         p = cxt->realloc(NULL, tot);
 169         if (!p)
 170                 return 0;
 171
 172         memcpy(p, cxt->bph, sizeof(struct boot_param_header));
 173         /* offsets get fixed up later */
 174
 175         cxt->bph = (struct boot_param_header *)p;
 176         cxt->max_size = tot;
 177         pend = p + tot;
 178         p += HDR_SIZE;
 179
 180         memcpy(p, cxt->rgn[FT_RSVMAP].start, cxt->rgn[FT_RSVMAP].size);
 181         cxt->rgn[FT_RSVMAP].start = p;
 182         p += cxt->rgn[FT_RSVMAP].size;
 183
 184         memcpy(p, cxt->rgn[FT_STRUCT].start, cxt->rgn[FT_STRUCT].size);
 185         ft_node_update_after(cxt, cxt->rgn[FT_STRUCT].start,
 186                         p - cxt->rgn[FT_STRUCT].start);
 187         cxt->p += p - cxt->rgn[FT_STRUCT].start;
 188         cxt->rgn[FT_STRUCT].start = p;
 189
 190         p = pend - cxt->rgn[FT_STRINGS].size;
 191         memcpy(p, cxt->rgn[FT_STRINGS].start, cxt->rgn[FT_STRINGS].size);
 192         stroff = cxt->str_anchor - cxt->rgn[FT_STRINGS].start;
 193         cxt->rgn[FT_STRINGS].start = p;
 194         cxt->str_anchor = p + stroff;
 195
 196         cxt->isordered = 1;
 197         return 1;
 198 }
 199
 200 static inline char *prev_end(struct ft_cxt *cxt, enum ft_rgn_id r)
 201 {
 202         if (r > FT_RSVMAP)
 203                 return cxt->rgn[r - 1].start + cxt->rgn[r - 1].size;
 204         return (char *)cxt->bph + HDR_SIZE;
 205 }
 206
 207 static inline char *next_start(struct ft_cxt *cxt, enum ft_rgn_id r)
 208 {
 209         if (r < FT_STRINGS)
 210                 return cxt->rgn[r + 1].start;
 211         return (char *)cxt->bph + cxt->max_size;
 212 }
 213
 214 /*
 215  * See if we can expand region rgn by nextra bytes by using up
 216  * free space after or before the region.
 217  */
 218 static int ft_shuffle(struct ft_cxt *cxt, char **pp, enum ft_rgn_id rgn,
 219                 int nextra)
 220 {
 221         char *p = *pp;
 222         char *rgn_start, *rgn_end;
 223
 224         rgn_start = cxt->rgn[rgn].start;
 225         rgn_end = rgn_start + cxt->rgn[rgn].size;
 226         if (nextra <= 0 || rgn_end + nextra <= next_start(cxt, rgn)) {
 227                 /* move following stuff */
 228                 if (p < rgn_end) {
 229                         if (nextra < 0)
 230                                 memmove(p, p - nextra, rgn_end - p + nextra);
 231                         else
 232                                 memmove(p + nextra, p, rgn_end - p);
 233                         if (rgn == FT_STRUCT)
 234                                 ft_node_update_after(cxt, p, nextra);
 235                 }
 236                 cxt->rgn[rgn].size += nextra;
 237                 if (rgn == FT_STRINGS)
 238                         /* assumes strings only added at beginning */
 239                         cxt->str_anchor += nextra;
 240                 return 1;
 241         }
 242         if (prev_end(cxt, rgn) <= rgn_start - nextra) {
 243                 /* move preceding stuff */
 244                 if (p > rgn_start) {
 245                         memmove(rgn_start - nextra, rgn_start, p - rgn_start);
 246                         if (rgn == FT_STRUCT)
 247                                 ft_node_update_before(cxt, p, -nextra);
 248                 }
 249                 *pp -= nextra;
 250                 cxt->rgn[rgn].start -= nextra;
 251                 cxt->rgn[rgn].size += nextra;
 252                 return 1;
 253         }
 254         return 0;
 255 }
 256
 257 static int ft_make_space(struct ft_cxt *cxt, char **pp, enum ft_rgn_id rgn,
 258                          int nextra)
 259 {
 260         unsigned long size, ssize, tot;
 261         char *str, *next;
 262         enum ft_rgn_id r;
 263
 264         if (!cxt->isordered) {
 265                 unsigned long rgn_off = *pp - cxt->rgn[rgn].start;
 266
 267                 if (!ft_reorder(cxt, nextra))
 268                         return 0;
 269
 270                 *pp = cxt->rgn[rgn].start + rgn_off;
 271         }
 272         if (ft_shuffle(cxt, pp, rgn, nextra))
 273                 return 1;
 274
 275         /* See if there is space after the strings section */
 276         ssize = cxt->rgn[FT_STRINGS].size;
 277         if (cxt->rgn[FT_STRINGS].start + ssize
 278                         < (char *)cxt->bph + cxt->max_size) {
 279                 /* move strings up as far as possible */
 280                 str = (char *)cxt->bph + cxt->max_size - ssize;
 281                 cxt->str_anchor += str - cxt->rgn[FT_STRINGS].start;
 282                 memmove(str, cxt->rgn[FT_STRINGS].start, ssize);
 283                 cxt->rgn[FT_STRINGS].start = str;
 284                 /* enough space now? */
 285                 if (rgn >= FT_STRUCT && ft_shuffle(cxt, pp, rgn, nextra))
 286                         return 1;
 287         }
 288
 289         /* how much total free space is there following this region? */
 290         tot = 0;
 291         for (r = rgn; r < FT_STRINGS; ++r) {
 292                 char *r_end = cxt->rgn[r].start + cxt->rgn[r].size;
 293                 tot += next_start(cxt, rgn) - r_end;
 294         }
 295
 296         /* cast is to shut gcc up; we know nextra >= 0 */
 297         if (tot < (unsigned int)nextra) {
 298                 /* have to reallocate */
 299                 char *newp, *new_start;
 300                 int shift;
 301
 302                 if (!cxt->realloc)
 303                         return 0;
 304                 size = _ALIGN(cxt->max_size + (nextra - tot) + EXPAND_INCR, 8);
 305                 newp = cxt->realloc(cxt->bph, size);
 306                 if (!newp)
 307                         return 0;
 308                 cxt->max_size = size;
 309                 shift = newp - (char *)cxt->bph;
 310
 311                 if (shift) { /* realloc can return same addr */
 312                         cxt->bph = (struct boot_param_header *)newp;
 313                         ft_node_update_after(cxt, cxt->rgn[FT_STRUCT].start,
 314                                         shift);
 315                         for (r = FT_RSVMAP; r <= FT_STRINGS; ++r) {
 316                                 new_start = cxt->rgn[r].start + shift;
 317                                 cxt->rgn[r].start = new_start;
 318                         }
 319                         *pp += shift;
 320                         cxt->str_anchor += shift;
 321                 }
 322
 323                 /* move strings up to the end */
 324                 str = newp + size - ssize;
 325                 cxt->str_anchor += str - cxt->rgn[FT_STRINGS].start;
 326                 memmove(str, cxt->rgn[FT_STRINGS].start, ssize);
 327                 cxt->rgn[FT_STRINGS].start = str;
 328
 329                 if (ft_shuffle(cxt, pp, rgn, nextra))
 330                         return 1;
 331         }
 332
 333         /* must be FT_RSVMAP and we need to move FT_STRUCT up */
 334         if (rgn == FT_RSVMAP) {
 335                 next = cxt->rgn[FT_RSVMAP].start + cxt->rgn[FT_RSVMAP].size
 336                         + nextra;
 337                 ssize = cxt->rgn[FT_STRUCT].size;
 338                 if (next + ssize >= cxt->rgn[FT_STRINGS].start)
 339                         return 0;       /* "can't happen" */
 340                 memmove(next, cxt->rgn[FT_STRUCT].start, ssize);
 341                 ft_node_update_after(cxt, cxt->rgn[FT_STRUCT].start, nextra);
 342                 cxt->rgn[FT_STRUCT].start = next;
 343
 344                 if (ft_shuffle(cxt, pp, rgn, nextra))
 345                         return 1;
 346         }
 347
 348         return 0;               /* "can't happen" */
 349 }
 350
 351 static void ft_put_word(struct ft_cxt *cxt, u32 v)
 352 {
 353         *(u32 *) cxt->p = cpu_to_be32(v);
 354         cxt->p += 4;
 355 }
 356
 357 static void ft_put_bin(struct ft_cxt *cxt, const void *data, unsigned int sz)
 358 {
 359         unsigned long sza = _ALIGN(sz, 4);
 360
 361         /* zero out the alignment gap if necessary */
 362         if (sz < sza)
 363                 *(u32 *) (cxt->p + sza - 4) = 0;
 364
 365         /* copy in the data */
 366         memcpy(cxt->p, data, sz);
 367
 368         cxt->p += sza;
 369 }
 370
 371 int ft_begin_node(struct ft_cxt *cxt, const char *name)
 372 {
 373         unsigned long nlen = strlen(name) + 1;
 374         unsigned long len = 8 + _ALIGN(nlen, 4);
 375
 376         if (!ft_make_space(cxt, &cxt->p, FT_STRUCT, len))
 377                 return -1;
 378         ft_put_word(cxt, OF_DT_BEGIN_NODE);
 379         ft_put_bin(cxt, name, strlen(name) + 1);
 380         return 0;
 381 }
 382
 383 void ft_end_node(struct ft_cxt *cxt)
 384 {
 385         ft_put_word(cxt, OF_DT_END_NODE);
 386 }
 387
 388 void ft_nop(struct ft_cxt *cxt)
 389 {
 390         if (ft_make_space(cxt, &cxt->p, FT_STRUCT, 4))
 391                 ft_put_word(cxt, OF_DT_NOP);
 392 }
 393
 394 #define NO_STRING       0x7fffffff
 395
 396 static int lookup_string(struct ft_cxt *cxt, const char *name)
 397 {
 398         char *p, *end;
 399
 400         p = cxt->rgn[FT_STRINGS].start;
 401         end = p + cxt->rgn[FT_STRINGS].size;
 402         while (p < end) {
 403                 if (strcmp(p, (char *)name) == 0)
 404                         return p - cxt->str_anchor;
 405                 p += strlen(p) + 1;
 406         }
 407
 408         return NO_STRING;
 409 }
 410
 411 /* lookup string and insert if not found */
 412 static int map_string(struct ft_cxt *cxt, const char *name)
 413 {
 414         int off;
 415         char *p;
 416
 417         off = lookup_string(cxt, name);
 418         if (off != NO_STRING)
 419                 return off;
 420         p = cxt->rgn[FT_STRINGS].start;
 421         if (!ft_make_space(cxt, &p, FT_STRINGS, strlen(name) + 1))
 422                 return NO_STRING;
 423         strcpy(p, name);
 424         return p - cxt->str_anchor;
 425 }
 426
 427 int ft_prop(struct ft_cxt *cxt, const char *name, const void *data,
 428                 unsigned int sz)
 429 {
 430         int off, len;
 431
 432         off = lookup_string(cxt, name);
 433         if (off == NO_STRING)
 434                 return -1;
 435
 436         len = 12 + _ALIGN(sz, 4);
 437         if (!ft_make_space(cxt, &cxt->p, FT_STRUCT, len))
 438                 return -1;
 439
 440         ft_put_word(cxt, OF_DT_PROP);
 441         ft_put_word(cxt, sz);
 442         ft_put_word(cxt, off);
 443         ft_put_bin(cxt, data, sz);
 444         return 0;
 445 }
 446
 447 int ft_prop_str(struct ft_cxt *cxt, const char *name, const char *str)
 448 {
 449         return ft_prop(cxt, name, str, strlen(str) + 1);
 450 }
 451
 452 int ft_prop_int(struct ft_cxt *cxt, const char *name, unsigned int val)
 453 {
 454         u32 v = cpu_to_be32((u32) val);
 455
 456         return ft_prop(cxt, name, &v, 4);
 457 }
 458
 459 /* Calculate the size of the reserved map */
 460 static unsigned long rsvmap_size(struct ft_cxt *cxt)
 461 {
 462         struct ft_reserve *res;
 463
 464         res = (struct ft_reserve *)cxt->rgn[FT_RSVMAP].start;
 465         while (res->start || res->len)
 466                 ++res;
 467         return (char *)(res + 1) - cxt->rgn[FT_RSVMAP].start;
 468 }
 469
 470 /* Calculate the size of the struct region by stepping through it */
 471 static unsigned long struct_size(struct ft_cxt *cxt)
 472 {
 473         char *p = cxt->rgn[FT_STRUCT].start;
 474         char *next;
 475         struct ft_atom atom;
 476
 477         /* make check in ft_next happy */
 478         if (cxt->rgn[FT_STRUCT].size == 0)
 479                 cxt->rgn[FT_STRUCT].size = 0xfffffffful - (unsigned long)p;
 480
 481         while ((next = ft_next(cxt, p, &atom)) != NULL)
 482                 p = next;
 483         return p + 4 - cxt->rgn[FT_STRUCT].start;
 484 }
 485
 486 /* add `adj' on to all string offset values in the struct area */
 487 static void adjust_string_offsets(struct ft_cxt *cxt, int adj)
 488 {
 489         char *p = cxt->rgn[FT_STRUCT].start;
 490         char *next;
 491         struct ft_atom atom;
 492         int off;
 493
 494         while ((next = ft_next(cxt, p, &atom)) != NULL) {
 495                 if (atom.tag == OF_DT_PROP) {
 496                         off = be32_to_cpu(*(u32 *) (p + 8));
 497                         *(u32 *) (p + 8) = cpu_to_be32(off + adj);
 498                 }
 499                 p = next;
 500         }
 501 }
 502
 503 /* start construction of the flat OF tree from scratch */
 504 void ft_begin(struct ft_cxt *cxt, void *blob, unsigned int max_size,
 505                 void *(*realloc_fn) (void *, unsigned long))
 506 {
 507         struct boot_param_header *bph = blob;
 508         char *p;
 509         struct ft_reserve *pres;
 510
 511         /* clear the cxt */
 512         memset(cxt, 0, sizeof(*cxt));
 513
 514         cxt->bph = bph;
 515         cxt->max_size = max_size;
 516         cxt->realloc = realloc_fn;
 517         cxt->isordered = 1;
 518
 519         /* zero everything in the header area */
 520         memset(bph, 0, sizeof(*bph));
 521
 522         bph->magic = cpu_to_be32(OF_DT_HEADER);
 523         bph->version = cpu_to_be32(0x10);
 524         bph->last_comp_version = cpu_to_be32(0x10);
 525
 526         /* start pointers */
 527         cxt->rgn[FT_RSVMAP].start = p = blob + HDR_SIZE;
 528         cxt->rgn[FT_RSVMAP].size = sizeof(struct ft_reserve);
 529         pres = (struct ft_reserve *)p;
 530         cxt->rgn[FT_STRUCT].start = p += sizeof(struct ft_reserve);
 531         cxt->rgn[FT_STRUCT].size = 4;
 532         cxt->rgn[FT_STRINGS].start = blob + max_size;
 533         cxt->rgn[FT_STRINGS].size = 0;
 534
 535         /* init rsvmap and struct */
 536         pres->start = 0;
 537         pres->len = 0;
 538         *(u32 *) p = cpu_to_be32(OF_DT_END);
 539
 540         cxt->str_anchor = blob;
 541 }
 542
 543 /* open up an existing blob to be examined or modified */
 544 int ft_open(struct ft_cxt *cxt, void *blob, unsigned int max_size,
 545                 unsigned int max_find_device,
 546                 void *(*realloc_fn) (void *, unsigned long))
 547 {
 548         struct boot_param_header *bph = blob;
 549
 550         /* can't cope with version < 16 */
 551         if (be32_to_cpu(bph->version) < 16)
 552                 return -1;
 553
 554         /* clear the cxt */
 555         memset(cxt, 0, sizeof(*cxt));
 556
 557         /* alloc node_tbl to track node ptrs returned by ft_find_device */
 558         ++max_find_device;
 559         cxt->node_tbl = realloc_fn(NULL, max_find_device * sizeof(char *));
 560         if (!cxt->node_tbl)
 561                 return -1;
 562         memset(cxt->node_tbl, 0, max_find_device * sizeof(char *));
 563         cxt->node_max = max_find_device;
 564         cxt->nodes_used = 1;    /* don't use idx 0 b/c looks like NULL */
 565
 566         cxt->bph = bph;
 567         cxt->max_size = max_size;
 568         cxt->realloc = realloc_fn;
 569
 570         cxt->rgn[FT_RSVMAP].start = blob + be32_to_cpu(bph->off_mem_rsvmap);
 571         cxt->rgn[FT_RSVMAP].size = rsvmap_size(cxt);
 572         cxt->rgn[FT_STRUCT].start = blob + be32_to_cpu(bph->off_dt_struct);
 573         cxt->rgn[FT_STRUCT].size = struct_size(cxt);
 574         cxt->rgn[FT_STRINGS].start = blob + be32_to_cpu(bph->off_dt_strings);
 575         cxt->rgn[FT_STRINGS].size = be32_to_cpu(bph->dt_strings_size);
 576         /* Leave as '0' to force first ft_make_space call to do a ft_reorder
 577          * and move dt to an area allocated by realloc.
 578         cxt->isordered = ft_ordered(cxt);
 579         */
 580
 581         cxt->p = cxt->rgn[FT_STRUCT].start;
 582         cxt->str_anchor = cxt->rgn[FT_STRINGS].start;
 583
 584         return 0;
 585 }
 586
 587 /* add a reserver physical area to the rsvmap */
 588 int ft_add_rsvmap(struct ft_cxt *cxt, u64 physaddr, u64 size)
 589 {
 590         char *p;
 591         struct ft_reserve *pres;
 592
 593         p = cxt->rgn[FT_RSVMAP].start + cxt->rgn[FT_RSVMAP].size
 594                 - sizeof(struct ft_reserve);
 595         if (!ft_make_space(cxt, &p, FT_RSVMAP, sizeof(struct ft_reserve)))
 596                 return -1;
 597
 598         pres = (struct ft_reserve *)p;
 599         pres->start = cpu_to_be64(physaddr);
 600         pres->len = cpu_to_be64(size);
 601
 602         return 0;
 603 }
 604
 605 void ft_begin_tree(struct ft_cxt *cxt)
 606 {
 607         cxt->p = ft_root_node(cxt);
 608 }
 609
 610 void ft_end_tree(struct ft_cxt *cxt)
 611 {
 612         struct boot_param_header *bph = cxt->bph;
 613         char *p, *oldstr, *str, *endp;
 614         unsigned long ssize;
 615         int adj;
 616
 617         if (!cxt->isordered)
 618                 return;         /* we haven't touched anything */
 619
 620         /* adjust string offsets */
 621         oldstr = cxt->rgn[FT_STRINGS].start;
 622         adj = cxt->str_anchor - oldstr;
 623         if (adj)
 624                 adjust_string_offsets(cxt, adj);
 625
 626         /* make strings end on 8-byte boundary */
 627         ssize = cxt->rgn[FT_STRINGS].size;
 628         endp = (char *)_ALIGN((unsigned long)cxt->rgn[FT_STRUCT].start
 629                         + cxt->rgn[FT_STRUCT].size + ssize, 8);
 630         str = endp - ssize;
 631
 632         /* move strings down to end of structs */
 633         memmove(str, oldstr, ssize);
 634         cxt->str_anchor = str;
 635         cxt->rgn[FT_STRINGS].start = str;
 636
 637         /* fill in header fields */
 638         p = (char *)bph;
 639         bph->totalsize = cpu_to_be32(endp - p);
 640         bph->off_mem_rsvmap = cpu_to_be32(cxt->rgn[FT_RSVMAP].start - p);
 641         bph->off_dt_struct = cpu_to_be32(cxt->rgn[FT_STRUCT].start - p);
 642         bph->off_dt_strings = cpu_to_be32(cxt->rgn[FT_STRINGS].start - p);
 643         bph->dt_strings_size = cpu_to_be32(ssize);
 644 }
 645
 646 void *ft_find_device(struct ft_cxt *cxt, const char *srch_path)
 647 {
 648         char *node;
 649
 650         /* require absolute path */
 651         if (srch_path[0] != '/')
 652                 return NULL;
 653         node = ft_find_descendent(cxt, ft_root_node(cxt), srch_path);
 654         return ft_get_phandle(cxt, node);
 655 }
 656
 657 void *ft_find_descendent(struct ft_cxt *cxt, void *top, const char *srch_path)
 658 {
 659         struct ft_atom atom;
 660         char *p;
 661         const char *cp, *q;
 662         int cl;
 663         int depth = -1;
 664         int dmatch = 0;
 665         const char *path_comp[FT_MAX_DEPTH];
 666
 667         cp = srch_path;
 668         cl = 0;
 669         p = top;
 670
 671         while ((p = ft_next(cxt, p, &atom)) != NULL) {
 672                 switch (atom.tag) {
 673                 case OF_DT_BEGIN_NODE:
 674                         ++depth;
 675                         if (depth != dmatch)
 676                                 break;
 677                         cxt->genealogy[depth] = atom.data;
 678                         cxt->genealogy[depth + 1] = NULL;
 679                         if (depth && !(strncmp(atom.name, cp, cl) == 0
 680                                         && (atom.name[cl] == '/'
 681                                                 || atom.name[cl] == '\0'
 682                                                 || atom.name[cl] == '@')))
 683                                 break;
 684                         path_comp[dmatch] = cp;
 685                         /* it matches so far, advance to next path component */
 686                         cp += cl;
 687                         /* skip slashes */
 688                         while (*cp == '/')
 689                                 ++cp;
 690                         /* we're done if this is the end of the string */
 691                         if (*cp == 0)
 692                                 return atom.data;
 693                         /* look for end of this component */
 694                         q = strchr(cp, '/');
 695                         if (q)
 696                                 cl = q - cp;
 697                         else
 698                                 cl = strlen(cp);
 699                         ++dmatch;
 700                         break;
 701                 case OF_DT_END_NODE:
 702                         if (depth == 0)
 703                                 return NULL;
 704                         if (dmatch > depth) {
 705                                 --dmatch;
 706                                 cl = cp - path_comp[dmatch] - 1;
 707                                 cp = path_comp[dmatch];
 708                                 while (cl > 0 && cp[cl - 1] == '/')
 709                                         --cl;
 710                         }
 711                         --depth;
 712                         break;
 713                 }
 714         }
 715         return NULL;
 716 }
 717
 718 void *ft_get_parent(struct ft_cxt *cxt, const void *phandle)
 719 {
 720         void *node;
 721         int d;
 722         struct ft_atom atom;
 723         char *p;
 724
 725         node = ft_node_ph2node(cxt, phandle);
 726         if (node == NULL)
 727                 return NULL;
 728
 729         for (d = 0; cxt->genealogy[d] != NULL; ++d)
 730                 if (cxt->genealogy[d] == node)
 731                         return cxt->genealogy[d > 0 ? d - 1 : 0];
 732
 733         /* have to do it the hard way... */
 734         p = ft_root_node(cxt);
 735         d = 0;
 736         while ((p = ft_next(cxt, p, &atom)) != NULL) {
 737                 switch (atom.tag) {
 738                 case OF_DT_BEGIN_NODE:
 739                         cxt->genealogy[d] = atom.data;
 740                         if (node == atom.data) {
 741                                 /* found it */
 742                                 cxt->genealogy[d + 1] = NULL;
 743                                 return d > 0 ? cxt->genealogy[d - 1] : node;
 744                         }
 745                         ++d;
 746                         break;
 747                 case OF_DT_END_NODE:
 748                         --d;
 749                         break;
 750                 }
 751         }
 752         return NULL;
 753 }
 754
 755 int ft_get_prop(struct ft_cxt *cxt, const void *phandle, const char *propname,
 756                 void *buf, const unsigned int buflen)
 757 {
 758         struct ft_atom atom;
 759         void *node;
 760         char *p;
 761         int depth;
 762         unsigned int size;
 763
 764         node = ft_node_ph2node(cxt, phandle);
 765         if (node == NULL)
 766                 return -1;
 767
 768         depth = 0;
 769         p = (char *)node;
 770
 771         while ((p = ft_next(cxt, p, &atom)) != NULL) {
 772                 switch (atom.tag) {
 773                 case OF_DT_BEGIN_NODE:
 774                         ++depth;
 775                         break;
 776                 case OF_DT_PROP:
 777                         if ((depth != 1) || strcmp(atom.name, propname))
 778                                 break;
 779                         size = min(atom.size, buflen);
 780                         memcpy(buf, atom.data, size);
 781                         return atom.size;
 782                 case OF_DT_END_NODE:
 783                         if (--depth <= 0)
 784                                 return -1;
 785                 }
 786         }
 787         return -1;
 788 }
 789
 790 int ft_set_prop(struct ft_cxt *cxt, const void *phandle, const char *propname,
 791                 const void *buf, const unsigned int buflen)
 792 {
 793         struct ft_atom atom;
 794         void *node;
 795         char *p, *next;
 796         int nextra, depth;
 797
 798         node = ft_node_ph2node(cxt, phandle);
 799         if (node == NULL)
 800                 return -1;
 801
 802         depth = 0;
 803         p = node;
 804
 805         while ((next = ft_next(cxt, p, &atom)) != NULL) {
 806                 switch (atom.tag) {
 807                 case OF_DT_BEGIN_NODE:
 808                         ++depth;
 809                         break;
 810                 case OF_DT_END_NODE:
 811                         if (--depth > 0)
 812                                 break;
 813                         /* haven't found the property, insert here */
 814                         cxt->p = p;
 815                         return ft_prop(cxt, propname, buf, buflen);
 816                 case OF_DT_PROP:
 817                         if ((depth != 1) || strcmp(atom.name, propname))
 818                                 break;
 819                         /* found an existing property, overwrite it */
 820                         nextra = _ALIGN(buflen, 4) - _ALIGN(atom.size, 4);
 821                         cxt->p = atom.data;
 822                         if (nextra && !ft_make_space(cxt, &cxt->p, FT_STRUCT,
 823                                                 nextra))
 824                                 return -1;
 825                         *(u32 *) (cxt->p - 8) = cpu_to_be32(buflen);
 826                         ft_put_bin(cxt, buf, buflen);
 827                         return 0;
 828                 }
 829                 p = next;
 830         }
 831         return -1;
 832 }
 833
 834 int ft_del_prop(struct ft_cxt *cxt, const void *phandle, const char *propname)
 835 {
 836         struct ft_atom atom;
 837         void *node;
 838         char *p, *next;
 839         int size;
 840
 841         node = ft_node_ph2node(cxt, phandle);
 842         if (node == NULL)
 843                 return -1;
 844
 845         p = node;
 846         while ((next = ft_next(cxt, p, &atom)) != NULL) {
 847                 switch (atom.tag) {
 848                 case OF_DT_BEGIN_NODE:
 849                 case OF_DT_END_NODE:
 850                         return -1;
 851                 case OF_DT_PROP:
 852                         if (strcmp(atom.name, propname))
 853                                 break;
 854                         /* found the property, remove it */
 855                         size = 12 + -_ALIGN(atom.size, 4);
 856                         cxt->p = p;
 857                         if (!ft_make_space(cxt, &cxt->p, FT_STRUCT, -size))
 858                                 return -1;
 859                         return 0;
 860                 }
 861                 p = next;
 862         }
 863         return -1;
 864 }
 865
 866 void *ft_create_node(struct ft_cxt *cxt, const void *parent, const char *path)
 867 {
 868         struct ft_atom atom;
 869         char *p, *next;
 870         int depth = 0;
 871
 872         p = ft_root_node(cxt);
 873         while ((next = ft_next(cxt, p, &atom)) != NULL) {
 874                 switch (atom.tag) {
 875                 case OF_DT_BEGIN_NODE:
 876                         ++depth;
 877                         if (depth == 1 && strcmp(atom.name, path) == 0)
 878                                 /* duplicate node path, return error */
 879                                 return NULL;
 880                         break;
 881                 case OF_DT_END_NODE:
 882                         --depth;
 883                         if (depth > 0)
 884                                 break;
 885                         /* end of node, insert here */
 886                         cxt->p = p;
 887                         ft_begin_node(cxt, path);
 888                         ft_end_node(cxt);
 889                         return p;
 890                 }
 891                 p = next;
 892         }
 893         return NULL;
 894 }