drivers/of/address.c

   1
   2 #include <linux/device.h>
   3 #include <linux/io.h>
   4 #include <linux/ioport.h>
   5 #include <linux/module.h>
   6 #include <linux/of_address.h>
   7 #include <linux/pci_regs.h>
   8 #include <linux/string.h>
   9
  10 /* Max address size we deal with */
  11 #define OF_MAX_ADDR_CELLS       4
  12 #define OF_CHECK_ADDR_COUNT(na) ((na) > 0 && (na) <= OF_MAX_ADDR_CELLS)
  13 #define OF_CHECK_COUNTS(na, ns) (OF_CHECK_ADDR_COUNT(na) && (ns) > 0)
  14
  15 static struct of_bus *of_match_bus(struct device_node *np);
  16 static int __of_address_to_resource(struct device_node *dev,
  17                 const __be32 *addrp, u64 size, unsigned int flags,
  18                 const char *name, struct resource *r);
  19
  20 /* Debug utility */
  21 #ifdef DEBUG
  22 static void of_dump_addr(const char *s, const __be32 *addr, int na)
  23 {
  24         printk(KERN_DEBUG "%s", s);
  25         while (na--)
  26                 printk(" %08x", be32_to_cpu(*(addr++)));
  27         printk("\n");
  28 }
  29 #else
  30 static void of_dump_addr(const char *s, const __be32 *addr, int na) { }
  31 #endif
  32
  33 /* Callbacks for bus specific translators */
  34 struct of_bus {
  35         const char      *name;
  36         const char      *addresses;
  37         int             (*match)(struct device_node *parent);
  38         void            (*count_cells)(struct device_node *child,
  39                                        int *addrc, int *sizec);
  40         u64             (*map)(__be32 *addr, const __be32 *range,
  41                                 int na, int ns, int pna);
  42         int             (*translate)(__be32 *addr, u64 offset, int na);
  43         unsigned int    (*get_flags)(const __be32 *addr);
  44 };
  45
  46 /*
  47  * Default translator (generic bus)
  48  */
  49
  50 static void of_bus_default_count_cells(struct device_node *dev,
  51                                        int *addrc, int *sizec)
  52 {
  53         if (addrc)
  54                 *addrc = of_n_addr_cells(dev);
  55         if (sizec)
  56                 *sizec = of_n_size_cells(dev);
  57 }
  58
  59 static u64 of_bus_default_map(__be32 *addr, const __be32 *range,
  60                 int na, int ns, int pna)
  61 {
  62         u64 cp, s, da;
  63
  64         cp = of_read_number(range, na);
  65         s  = of_read_number(range + na + pna, ns);
  66         da = of_read_number(addr, na);
  67
  68         pr_debug("OF: default map, cp=%llx, s=%llx, da=%llx\n",
  69                  (unsigned long long)cp, (unsigned long long)s,
  70                  (unsigned long long)da);
  71
  72         /*
  73          * If the number of address cells is larger than 2 we assume the
  74          * mapping doesn't specify a physical address. Rather, the address
  75          * specifies an identifier that must match exactly.
  76          */
  77         if (na > 2 && memcmp(range, addr, na * 4) != 0)
  78                 return OF_BAD_ADDR;
  79
  80         if (da < cp || da >= (cp + s))
  81                 return OF_BAD_ADDR;
  82         return da - cp;
  83 }
  84
  85 static int of_bus_default_translate(__be32 *addr, u64 offset, int na)
  86 {
  87         u64 a = of_read_number(addr, na);
  88         memset(addr, 0, na * 4);
  89         a += offset;
  90         if (na > 1)
  91                 addr[na - 2] = cpu_to_be32(a >> 32);
  92         addr[na - 1] = cpu_to_be32(a & 0xffffffffu);
  93
  94         return 0;
  95 }
  96
  97 static unsigned int of_bus_default_get_flags(const __be32 *addr)
  98 {
  99         return IORESOURCE_MEM;
 100 }
 101
 102 #ifdef CONFIG_PCI
 103 /*
 104  * PCI bus specific translator
 105  */
 106
 107 static int of_bus_pci_match(struct device_node *np)
 108 {
 109         /* "vci" is for the /chaos bridge on 1st-gen PCI powermacs */
 110         return !strcmp(np->type, "pci") || !strcmp(np->type, "vci");
 111 }
 112
 113 static void of_bus_pci_count_cells(struct device_node *np,
 114                                    int *addrc, int *sizec)
 115 {
 116         if (addrc)
 117                 *addrc = 3;
 118         if (sizec)
 119                 *sizec = 2;
 120 }
 121
 122 static unsigned int of_bus_pci_get_flags(const __be32 *addr)
 123 {
 124         unsigned int flags = 0;
 125         u32 w = be32_to_cpup(addr);
 126
 127         switch((w >> 24) & 0x03) {
 128         case 0x01:
 129                 flags |= IORESOURCE_IO;
 130                 break;
 131         case 0x02: /* 32 bits */
 132         case 0x03: /* 64 bits */
 133                 flags |= IORESOURCE_MEM;
 134                 break;
 135         }
 136         if (w & 0x40000000)
 137                 flags |= IORESOURCE_PREFETCH;
 138         return flags;
 139 }
 140
 141 static u64 of_bus_pci_map(__be32 *addr, const __be32 *range, int na, int ns,
 142                 int pna)
 143 {
 144         u64 cp, s, da;
 145         unsigned int af, rf;
 146
 147         af = of_bus_pci_get_flags(addr);
 148         rf = of_bus_pci_get_flags(range);
 149
 150         /* Check address type match */
 151         if ((af ^ rf) & (IORESOURCE_MEM | IORESOURCE_IO))
 152                 return OF_BAD_ADDR;
 153
 154         /* Read address values, skipping high cell */
 155         cp = of_read_number(range + 1, na - 1);
 156         s  = of_read_number(range + na + pna, ns);
 157         da = of_read_number(addr + 1, na - 1);
 158
 159         pr_debug("OF: PCI map, cp=%llx, s=%llx, da=%llx\n",
 160                  (unsigned long long)cp, (unsigned long long)s,
 161                  (unsigned long long)da);
 162
 163         if (da < cp || da >= (cp + s))
 164                 return OF_BAD_ADDR;
 165         return da - cp;
 166 }
 167
 168 static int of_bus_pci_translate(__be32 *addr, u64 offset, int na)
 169 {
 170         return of_bus_default_translate(addr + 1, offset, na - 1);
 171 }
 172
 173 const __be32 *of_get_pci_address(struct device_node *dev, int bar_no, u64 *size,
 174                         unsigned int *flags)
 175 {
 176         const __be32 *prop;
 177         unsigned int psize;
 178         struct device_node *parent;
 179         struct of_bus *bus;
 180         int onesize, i, na, ns;
 181
 182         /* Get parent & match bus type */
 183         parent = of_get_parent(dev);
 184         if (parent == NULL)
 185                 return NULL;
 186         bus = of_match_bus(parent);
 187         if (strcmp(bus->name, "pci")) {
 188                 of_node_put(parent);
 189                 return NULL;
 190         }
 191         bus->count_cells(dev, &na, &ns);
 192         of_node_put(parent);
 193         if (!OF_CHECK_ADDR_COUNT(na))
 194                 return NULL;
 195
 196         /* Get "reg" or "assigned-addresses" property */
 197         prop = of_get_property(dev, bus->addresses, &psize);
 198         if (prop == NULL)
 199                 return NULL;
 200         psize /= 4;
 201
 202         onesize = na + ns;
 203         for (i = 0; psize >= onesize; psize -= onesize, prop += onesize, i++) {
 204                 u32 val = be32_to_cpu(prop[0]);
 205                 if ((val & 0xff) == ((bar_no * 4) + PCI_BASE_ADDRESS_0)) {
 206                         if (size)
 207                                 *size = of_read_number(prop + na, ns);
 208                         if (flags)
 209                                 *flags = bus->get_flags(prop);
 210                         return prop;
 211                 }
 212         }
 213         return NULL;
 214 }
 215 EXPORT_SYMBOL(of_get_pci_address);
 216
 217 int of_pci_address_to_resource(struct device_node *dev, int bar,
 218                                struct resource *r)
 219 {
 220         const __be32    *addrp;
 221         u64             size;
 222         unsigned int    flags;
 223
 224         addrp = of_get_pci_address(dev, bar, &size, &flags);
 225         if (addrp == NULL)
 226                 return -EINVAL;
 227         return __of_address_to_resource(dev, addrp, size, flags, NULL, r);
 228 }
 229 EXPORT_SYMBOL_GPL(of_pci_address_to_resource);
 230
 231 int of_pci_range_parser_init(struct of_pci_range_parser *parser,
 232                                 struct device_node *node)
 233 {
 234         const int na = 3, ns = 2;
 235         int rlen;
 236
 237         parser->node = node;
 238         parser->pna = of_n_addr_cells(node);
 239         parser->np = parser->pna + na + ns;
 240
 241         parser->range = of_get_property(node, "ranges", &rlen);
 242         if (parser->range == NULL)
 243                 return -ENOENT;
 244
 245         parser->end = parser->range + rlen / sizeof(__be32);
 246
 247         return 0;
 248 }
 249 EXPORT_SYMBOL_GPL(of_pci_range_parser_init);
 250
 251 struct of_pci_range *of_pci_range_parser_one(struct of_pci_range_parser *parser,
 252                                                 struct of_pci_range *range)
 253 {
 254         const int na = 3, ns = 2;
 255
 256         if (!range)
 257                 return NULL;
 258
 259         if (!parser->range || parser->range + parser->np > parser->end)
 260                 return NULL;
 261
 262         range->pci_space = parser->range[0];
 263         range->flags = of_bus_pci_get_flags(parser->range);
 264         range->pci_addr = of_read_number(parser->range + 1, ns);
 265         range->cpu_addr = of_translate_address(parser->node,
 266                                 parser->range + na);
 267         range->size = of_read_number(parser->range + parser->pna + na, ns);
 268
 269         parser->range += parser->np;
 270
 271         /* Now consume following elements while they are contiguous */
 272         while (parser->range + parser->np <= parser->end) {
 273                 u32 flags, pci_space;
 274                 u64 pci_addr, cpu_addr, size;
 275
 276                 pci_space = be32_to_cpup(parser->range);
 277                 flags = of_bus_pci_get_flags(parser->range);
 278                 pci_addr = of_read_number(parser->range + 1, ns);
 279                 cpu_addr = of_translate_address(parser->node,
 280                                 parser->range + na);
 281                 size = of_read_number(parser->range + parser->pna + na, ns);
 282
 283                 if (flags != range->flags)
 284                         break;
 285                 if (pci_addr != range->pci_addr + range->size ||
 286                     cpu_addr != range->cpu_addr + range->size)
 287                         break;
 288
 289                 range->size += size;
 290                 parser->range += parser->np;
 291         }
 292
 293         return range;
 294 }
 295 EXPORT_SYMBOL_GPL(of_pci_range_parser_one);
 296
 297 #endif /* CONFIG_PCI */
 298
 299 /*
 300  * ISA bus specific translator
 301  */
 302
 303 static int of_bus_isa_match(struct device_node *np)
 304 {
 305         return !strcmp(np->name, "isa");
 306 }
 307
 308 static void of_bus_isa_count_cells(struct device_node *child,
 309                                    int *addrc, int *sizec)
 310 {
 311         if (addrc)
 312                 *addrc = 2;
 313         if (sizec)
 314                 *sizec = 1;
 315 }
 316
 317 static u64 of_bus_isa_map(__be32 *addr, const __be32 *range, int na, int ns,
 318                 int pna)
 319 {
 320         u64 cp, s, da;
 321
 322         /* Check address type match */
 323         if ((addr[0] ^ range[0]) & cpu_to_be32(1))
 324                 return OF_BAD_ADDR;
 325
 326         /* Read address values, skipping high cell */
 327         cp = of_read_number(range + 1, na - 1);
 328         s  = of_read_number(range + na + pna, ns);
 329         da = of_read_number(addr + 1, na - 1);
 330
 331         pr_debug("OF: ISA map, cp=%llx, s=%llx, da=%llx\n",
 332                  (unsigned long long)cp, (unsigned long long)s,
 333                  (unsigned long long)da);
 334
 335         if (da < cp || da >= (cp + s))
 336                 return OF_BAD_ADDR;
 337         return da - cp;
 338 }
 339
 340 static int of_bus_isa_translate(__be32 *addr, u64 offset, int na)
 341 {
 342         return of_bus_default_translate(addr + 1, offset, na - 1);
 343 }
 344
 345 static unsigned int of_bus_isa_get_flags(const __be32 *addr)
 346 {
 347         unsigned int flags = 0;
 348         u32 w = be32_to_cpup(addr);
 349
 350         if (w & 1)
 351                 flags |= IORESOURCE_IO;
 352         else
 353                 flags |= IORESOURCE_MEM;
 354         return flags;
 355 }
 356
 357 /*
 358  * Array of bus specific translators
 359  */
 360
 361 static struct of_bus of_busses[] = {
 362 #ifdef CONFIG_PCI
 363         /* PCI */
 364         {
 365                 .name = "pci",
 366                 .addresses = "assigned-addresses",
 367                 .match = of_bus_pci_match,
 368                 .count_cells = of_bus_pci_count_cells,
 369                 .map = of_bus_pci_map,
 370                 .translate = of_bus_pci_translate,
 371                 .get_flags = of_bus_pci_get_flags,
 372         },
 373 #endif /* CONFIG_PCI */
 374         /* ISA */
 375         {
 376                 .name = "isa",
 377                 .addresses = "reg",
 378                 .match = of_bus_isa_match,
 379                 .count_cells = of_bus_isa_count_cells,
 380                 .map = of_bus_isa_map,
 381                 .translate = of_bus_isa_translate,
 382                 .get_flags = of_bus_isa_get_flags,
 383         },
 384         /* Default */
 385         {
 386                 .name = "default",
 387                 .addresses = "reg",
 388                 .match = NULL,
 389                 .count_cells = of_bus_default_count_cells,
 390                 .map = of_bus_default_map,
 391                 .translate = of_bus_default_translate,
 392                 .get_flags = of_bus_default_get_flags,
 393         },
 394 };
 395
 396 static struct of_bus *of_match_bus(struct device_node *np)
 397 {
 398         int i;
 399
 400         for (i = 0; i < ARRAY_SIZE(of_busses); i++)
 401                 if (!of_busses[i].match || of_busses[i].match(np))
 402                         return &of_busses[i];
 403         BUG();
 404         return NULL;
 405 }
 406
 407 static int of_translate_one(struct device_node *parent, struct of_bus *bus,
 408                             struct of_bus *pbus, __be32 *addr,
 409                             int na, int ns, int pna, const char *rprop)
 410 {
 411         const __be32 *ranges;
 412         unsigned int rlen;
 413         int rone;
 414         u64 offset = OF_BAD_ADDR;
 415
 416         /* Normally, an absence of a "ranges" property means we are
 417          * crossing a non-translatable boundary, and thus the addresses
 418          * below the current not cannot be converted to CPU physical ones.
 419          * Unfortunately, while this is very clear in the spec, it's not
 420          * what Apple understood, and they do have things like /uni-n or
 421          * /ht nodes with no "ranges" property and a lot of perfectly
 422          * useable mapped devices below them. Thus we treat the absence of
 423          * "ranges" as equivalent to an empty "ranges" property which means
 424          * a 1:1 translation at that level. It's up to the caller not to try
 425          * to translate addresses that aren't supposed to be translated in
 426          * the first place. --BenH.
 427          *
 428          * As far as we know, this damage only exists on Apple machines, so
 429          * This code is only enabled on powerpc. --gcl
 430          */
 431         ranges = of_get_property(parent, rprop, &rlen);
 432 #if !defined(CONFIG_PPC)
 433         if (ranges == NULL) {
 434                 pr_err("OF: no ranges; cannot translate\n");
 435                 return 1;
 436         }
 437 #endif /* !defined(CONFIG_PPC) */
 438         if (ranges == NULL || rlen == 0) {
 439                 offset = of_read_number(addr, na);
 440                 memset(addr, 0, pna * 4);
 441                 pr_debug("OF: empty ranges; 1:1 translation\n");
 442                 goto finish;
 443         }
 444
 445         pr_debug("OF: walking ranges...\n");
 446
 447         /* Now walk through the ranges */
 448         rlen /= 4;
 449         rone = na + pna + ns;
 450         for (; rlen >= rone; rlen -= rone, ranges += rone) {
 451                 offset = bus->map(addr, ranges, na, ns, pna);
 452                 if (offset != OF_BAD_ADDR)
 453                         break;
 454         }
 455         if (offset == OF_BAD_ADDR) {
 456                 pr_debug("OF: not found !\n");
 457                 return 1;
 458         }
 459         memcpy(addr, ranges + na, 4 * pna);
 460
 461  finish:
 462         of_dump_addr("OF: parent translation for:", addr, pna);
 463         pr_debug("OF: with offset: %llx\n", (unsigned long long)offset);
 464
 465         /* Translate it into parent bus space */
 466         return pbus->translate(addr, offset, pna);
 467 }
 468
 469 /*
 470  * Translate an address from the device-tree into a CPU physical address,
 471  * this walks up the tree and applies the various bus mappings on the
 472  * way.
 473  *
 474  * Note: We consider that crossing any level with #size-cells == 0 to mean
 475  * that translation is impossible (that is we are not dealing with a value
 476  * that can be mapped to a cpu physical address). This is not really specified
 477  * that way, but this is traditionally the way IBM at least do things
 478  */
 479 static u64 __of_translate_address(struct device_node *dev,
 480                                   const __be32 *in_addr, const char *rprop)
 481 {
 482         struct device_node *parent = NULL;
 483         struct of_bus *bus, *pbus;
 484         __be32 addr[OF_MAX_ADDR_CELLS];
 485         int na, ns, pna, pns;
 486         u64 result = OF_BAD_ADDR;
 487
 488         pr_debug("OF: ** translation for device %s **\n", dev->full_name);
 489
 490         /* Increase refcount at current level */
 491         of_node_get(dev);
 492
 493         /* Get parent & match bus type */
 494         parent = of_get_parent(dev);
 495         if (parent == NULL)
 496                 goto bail;
 497         bus = of_match_bus(parent);
 498
 499         /* Count address cells & copy address locally */
 500         bus->count_cells(dev, &na, &ns);
 501         if (!OF_CHECK_COUNTS(na, ns)) {
 502                 printk(KERN_ERR "prom_parse: Bad cell count for %s\n",
 503                        dev->full_name);
 504                 goto bail;
 505         }
 506         memcpy(addr, in_addr, na * 4);
 507
 508         pr_debug("OF: bus is %s (na=%d, ns=%d) on %s\n",
 509             bus->name, na, ns, parent->full_name);
 510         of_dump_addr("OF: translating address:", addr, na);
 511
 512         /* Translate */
 513         for (;;) {
 514                 /* Switch to parent bus */
 515                 of_node_put(dev);
 516                 dev = parent;
 517                 parent = of_get_parent(dev);
 518
 519                 /* If root, we have finished */
 520                 if (parent == NULL) {
 521                         pr_debug("OF: reached root node\n");
 522                         result = of_read_number(addr, na);
 523                         break;
 524                 }
 525
 526                 /* Get new parent bus and counts */
 527                 pbus = of_match_bus(parent);
 528                 pbus->count_cells(dev, &pna, &pns);
 529                 if (!OF_CHECK_COUNTS(pna, pns)) {
 530                         printk(KERN_ERR "prom_parse: Bad cell count for %s\n",
 531                                dev->full_name);
 532                         break;
 533                 }
 534
 535                 pr_debug("OF: parent bus is %s (na=%d, ns=%d) on %s\n",
 536                     pbus->name, pna, pns, parent->full_name);
 537
 538                 /* Apply bus translation */
 539                 if (of_translate_one(dev, bus, pbus, addr, na, ns, pna, rprop))
 540                         break;
 541
 542                 /* Complete the move up one level */
 543                 na = pna;
 544                 ns = pns;
 545                 bus = pbus;
 546
 547                 of_dump_addr("OF: one level translation:", addr, na);
 548         }
 549  bail:
 550         of_node_put(parent);
 551         of_node_put(dev);
 552
 553         return result;
 554 }
 555
 556 u64 of_translate_address(struct device_node *dev, const __be32 *in_addr)
 557 {
 558         return __of_translate_address(dev, in_addr, "ranges");
 559 }
 560 EXPORT_SYMBOL(of_translate_address);
 561
 562 u64 of_translate_dma_address(struct device_node *dev, const __be32 *in_addr)
 563 {
 564         return __of_translate_address(dev, in_addr, "dma-ranges");
 565 }
 566 EXPORT_SYMBOL(of_translate_dma_address);
 567
 568 bool of_can_translate_address(struct device_node *dev)
 569 {
 570         struct device_node *parent;
 571         struct of_bus *bus;
 572         int na, ns;
 573
 574         parent = of_get_parent(dev);
 575         if (parent == NULL)
 576                 return false;
 577
 578         bus = of_match_bus(parent);
 579         bus->count_cells(dev, &na, &ns);
 580
 581         of_node_put(parent);
 582
 583         return OF_CHECK_COUNTS(na, ns);
 584 }
 585 EXPORT_SYMBOL(of_can_translate_address);
 586
 587 const __be32 *of_get_address(struct device_node *dev, int index, u64 *size,
 588                     unsigned int *flags)
 589 {
 590         const __be32 *prop;
 591         unsigned int psize;
 592         struct device_node *parent;
 593         struct of_bus *bus;
 594         int onesize, i, na, ns;
 595
 596         /* Get parent & match bus type */
 597         parent = of_get_parent(dev);
 598         if (parent == NULL)
 599                 return NULL;
 600         bus = of_match_bus(parent);
 601         bus->count_cells(dev, &na, &ns);
 602         of_node_put(parent);
 603         if (!OF_CHECK_ADDR_COUNT(na))
 604                 return NULL;
 605
 606         /* Get "reg" or "assigned-addresses" property */
 607         prop = of_get_property(dev, bus->addresses, &psize);
 608         if (prop == NULL)
 609                 return NULL;
 610         psize /= 4;
 611
 612         onesize = na + ns;
 613         for (i = 0; psize >= onesize; psize -= onesize, prop += onesize, i++)
 614                 if (i == index) {
 615                         if (size)
 616                                 *size = of_read_number(prop + na, ns);
 617                         if (flags)
 618                                 *flags = bus->get_flags(prop);
 619                         return prop;
 620                 }
 621         return NULL;
 622 }
 623 EXPORT_SYMBOL(of_get_address);
 624
 625 static int __of_address_to_resource(struct device_node *dev,
 626                 const __be32 *addrp, u64 size, unsigned int flags,
 627                 const char *name, struct resource *r)
 628 {
 629         u64 taddr;
 630
 631         if ((flags & (IORESOURCE_IO | IORESOURCE_MEM)) == 0)
 632                 return -EINVAL;
 633         taddr = of_translate_address(dev, addrp);
 634         if (taddr == OF_BAD_ADDR)
 635                 return -EINVAL;
 636         memset(r, 0, sizeof(struct resource));
 637         if (flags & IORESOURCE_IO) {
 638                 unsigned long port;
 639                 port = pci_address_to_pio(taddr);
 640                 if (port == (unsigned long)-1)
 641                         return -EINVAL;
 642                 r->start = port;
 643                 r->end = port + size - 1;
 644         } else {
 645                 r->start = taddr;
 646                 r->end = taddr + size - 1;
 647         }
 648         r->flags = flags;
 649         r->name = name ? name : dev->full_name;
 650
 651         return 0;
 652 }
 653
 654 /**
 655  * of_address_to_resource - Translate device tree address and return as resource
 656  *
 657  * Note that if your address is a PIO address, the conversion will fail if
 658  * the physical address can't be internally converted to an IO token with
 659  * pci_address_to_pio(), that is because it's either called to early or it
 660  * can't be matched to any host bridge IO space
 661  */
 662 int of_address_to_resource(struct device_node *dev, int index,
 663                            struct resource *r)
 664 {
 665         const __be32    *addrp;
 666         u64             size;
 667         unsigned int    flags;
 668         const char      *name = NULL;
 669
 670         addrp = of_get_address(dev, index, &size, &flags);
 671         if (addrp == NULL)
 672                 return -EINVAL;
 673
 674         /* Get optional "reg-names" property to add a name to a resource */
 675         of_property_read_string_index(dev, "reg-names", index, &name);
 676
 677         return __of_address_to_resource(dev, addrp, size, flags, name, r);
 678 }
 679 EXPORT_SYMBOL_GPL(of_address_to_resource);
 680
 681 struct device_node *of_find_matching_node_by_address(struct device_node *from,
 682                                         const struct of_device_id *matches,
 683                                         u64 base_address)
 684 {
 685         struct device_node *dn = of_find_matching_node(from, matches);
 686         struct resource res;
 687
 688         while (dn) {
 689                 if (of_address_to_resource(dn, 0, &res))
 690                         continue;
 691                 if (res.start == base_address)
 692                         return dn;
 693                 dn = of_find_matching_node(dn, matches);
 694         }
 695
 696         return NULL;
 697 }
 698
 699
 700 /**
 701  * of_iomap - Maps the memory mapped IO for a given device_node
 702  * @device:     the device whose io range will be mapped
 703  * @index:      index of the io range
 704  *
 705  * Returns a pointer to the mapped memory
 706  */
 707 void __iomem *of_iomap(struct device_node *np, int index)
 708 {
 709         struct resource res;
 710
 711         if (of_address_to_resource(np, index, &res))
 712                 return NULL;
 713
 714         return ioremap(res.start, resource_size(&res));
 715 }
 716 EXPORT_SYMBOL(of_iomap);