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         if (da < cp || da >= (cp + s))
  73                 return OF_BAD_ADDR;
  74         return da - cp;
  75 }
  76
  77 static int of_bus_default_translate(__be32 *addr, u64 offset, int na)
  78 {
  79         u64 a = of_read_number(addr, na);
  80         memset(addr, 0, na * 4);
  81         a += offset;
  82         if (na > 1)
  83                 addr[na - 2] = cpu_to_be32(a >> 32);
  84         addr[na - 1] = cpu_to_be32(a & 0xffffffffu);
  85
  86         return 0;
  87 }
  88
  89 static unsigned int of_bus_default_get_flags(const __be32 *addr)
  90 {
  91         return IORESOURCE_MEM;
  92 }
  93
  94 #ifdef CONFIG_OF_ADDRESS_PCI
  95 /*
  96  * PCI bus specific translator
  97  */
  98
  99 static int of_bus_pci_match(struct device_node *np)
 100 {
 101         /*
 102          * "pciex" is PCI Express
 103          * "vci" is for the /chaos bridge on 1st-gen PCI powermacs
 104          * "ht" is hypertransport
 105          */
 106         return !strcmp(np->type, "pci") || !strcmp(np->type, "pciex") ||
 107                 !strcmp(np->type, "vci") || !strcmp(np->type, "ht");
 108 }
 109
 110 static void of_bus_pci_count_cells(struct device_node *np,
 111                                    int *addrc, int *sizec)
 112 {
 113         if (addrc)
 114                 *addrc = 3;
 115         if (sizec)
 116                 *sizec = 2;
 117 }
 118
 119 static unsigned int of_bus_pci_get_flags(const __be32 *addr)
 120 {
 121         unsigned int flags = 0;
 122         u32 w = be32_to_cpup(addr);
 123
 124         switch((w >> 24) & 0x03) {
 125         case 0x01:
 126                 flags |= IORESOURCE_IO;
 127                 break;
 128         case 0x02: /* 32 bits */
 129         case 0x03: /* 64 bits */
 130                 flags |= IORESOURCE_MEM;
 131                 break;
 132         }
 133         if (w & 0x40000000)
 134                 flags |= IORESOURCE_PREFETCH;
 135         return flags;
 136 }
 137
 138 static u64 of_bus_pci_map(__be32 *addr, const __be32 *range, int na, int ns,
 139                 int pna)
 140 {
 141         u64 cp, s, da;
 142         unsigned int af, rf;
 143
 144         af = of_bus_pci_get_flags(addr);
 145         rf = of_bus_pci_get_flags(range);
 146
 147         /* Check address type match */
 148         if ((af ^ rf) & (IORESOURCE_MEM | IORESOURCE_IO))
 149                 return OF_BAD_ADDR;
 150
 151         /* Read address values, skipping high cell */
 152         cp = of_read_number(range + 1, na - 1);
 153         s  = of_read_number(range + na + pna, ns);
 154         da = of_read_number(addr + 1, na - 1);
 155
 156         pr_debug("OF: PCI map, cp=%llx, s=%llx, da=%llx\n",
 157                  (unsigned long long)cp, (unsigned long long)s,
 158                  (unsigned long long)da);
 159
 160         if (da < cp || da >= (cp + s))
 161                 return OF_BAD_ADDR;
 162         return da - cp;
 163 }
 164
 165 static int of_bus_pci_translate(__be32 *addr, u64 offset, int na)
 166 {
 167         return of_bus_default_translate(addr + 1, offset, na - 1);
 168 }
 169 #endif /* CONFIG_OF_ADDRESS_PCI */
 170
 171 #ifdef CONFIG_PCI
 172 const __be32 *of_get_pci_address(struct device_node *dev, int bar_no, u64 *size,
 173                         unsigned int *flags)
 174 {
 175         const __be32 *prop;
 176         unsigned int psize;
 177         struct device_node *parent;
 178         struct of_bus *bus;
 179         int onesize, i, na, ns;
 180
 181         /* Get parent & match bus type */
 182         parent = of_get_parent(dev);
 183         if (parent == NULL)
 184                 return NULL;
 185         bus = of_match_bus(parent);
 186         if (strcmp(bus->name, "pci")) {
 187                 of_node_put(parent);
 188                 return NULL;
 189         }
 190         bus->count_cells(dev, &na, &ns);
 191         of_node_put(parent);
 192         if (!OF_CHECK_ADDR_COUNT(na))
 193                 return NULL;
 194
 195         /* Get "reg" or "assigned-addresses" property */
 196         prop = of_get_property(dev, bus->addresses, &psize);
 197         if (prop == NULL)
 198                 return NULL;
 199         psize /= 4;
 200
 201         onesize = na + ns;
 202         for (i = 0; psize >= onesize; psize -= onesize, prop += onesize, i++) {
 203                 u32 val = be32_to_cpu(prop[0]);
 204                 if ((val & 0xff) == ((bar_no * 4) + PCI_BASE_ADDRESS_0)) {
 205                         if (size)
 206                                 *size = of_read_number(prop + na, ns);
 207                         if (flags)
 208                                 *flags = bus->get_flags(prop);
 209                         return prop;
 210                 }
 211         }
 212         return NULL;
 213 }
 214 EXPORT_SYMBOL(of_get_pci_address);
 215
 216 int of_pci_address_to_resource(struct device_node *dev, int bar,
 217                                struct resource *r)
 218 {
 219         const __be32    *addrp;
 220         u64             size;
 221         unsigned int    flags;
 222
 223         addrp = of_get_pci_address(dev, bar, &size, &flags);
 224         if (addrp == NULL)
 225                 return -EINVAL;
 226         return __of_address_to_resource(dev, addrp, size, flags, NULL, r);
 227 }
 228 EXPORT_SYMBOL_GPL(of_pci_address_to_resource);
 229
 230 int of_pci_range_parser_init(struct of_pci_range_parser *parser,
 231                                 struct device_node *node)
 232 {
 233         const int na = 3, ns = 2;
 234         int rlen;
 235
 236         parser->node = node;
 237         parser->pna = of_n_addr_cells(node);
 238         parser->np = parser->pna + na + ns;
 239
 240         parser->range = of_get_property(node, "ranges", &rlen);
 241         if (parser->range == NULL)
 242                 return -ENOENT;
 243
 244         parser->end = parser->range + rlen / sizeof(__be32);
 245
 246         return 0;
 247 }
 248 EXPORT_SYMBOL_GPL(of_pci_range_parser_init);
 249
 250 struct of_pci_range *of_pci_range_parser_one(struct of_pci_range_parser *parser,
 251                                                 struct of_pci_range *range)
 252 {
 253         const int na = 3, ns = 2;
 254
 255         if (!range)
 256                 return NULL;
 257
 258         if (!parser->range || parser->range + parser->np > parser->end)
 259                 return NULL;
 260
 261         range->pci_space = parser->range[0];
 262         range->flags = of_bus_pci_get_flags(parser->range);
 263         range->pci_addr = of_read_number(parser->range + 1, ns);
 264         range->cpu_addr = of_translate_address(parser->node,
 265                                 parser->range + na);
 266         range->size = of_read_number(parser->range + parser->pna + na, ns);
 267
 268         parser->range += parser->np;
 269
 270         /* Now consume following elements while they are contiguous */
 271         while (parser->range + parser->np <= parser->end) {
 272                 u32 flags, pci_space;
 273                 u64 pci_addr, cpu_addr, size;
 274
 275                 pci_space = be32_to_cpup(parser->range);
 276                 flags = of_bus_pci_get_flags(parser->range);
 277                 pci_addr = of_read_number(parser->range + 1, ns);
 278                 cpu_addr = of_translate_address(parser->node,
 279                                 parser->range + na);
 280                 size = of_read_number(parser->range + parser->pna + na, ns);
 281
 282                 if (flags != range->flags)
 283                         break;
 284                 if (pci_addr != range->pci_addr + range->size ||
 285                     cpu_addr != range->cpu_addr + range->size)
 286                         break;
 287
 288                 range->size += size;
 289                 parser->range += parser->np;
 290         }
 291
 292         return range;
 293 }
 294 EXPORT_SYMBOL_GPL(of_pci_range_parser_one);
 295
 296 #endif /* CONFIG_PCI */
 297
 298 /*
 299  * ISA bus specific translator
 300  */
 301
 302 static int of_bus_isa_match(struct device_node *np)
 303 {
 304         return !strcmp(np->name, "isa");
 305 }
 306
 307 static void of_bus_isa_count_cells(struct device_node *child,
 308                                    int *addrc, int *sizec)
 309 {
 310         if (addrc)
 311                 *addrc = 2;
 312         if (sizec)
 313                 *sizec = 1;
 314 }
 315
 316 static u64 of_bus_isa_map(__be32 *addr, const __be32 *range, int na, int ns,
 317                 int pna)
 318 {
 319         u64 cp, s, da;
 320
 321         /* Check address type match */
 322         if ((addr[0] ^ range[0]) & cpu_to_be32(1))
 323                 return OF_BAD_ADDR;
 324
 325         /* Read address values, skipping high cell */
 326         cp = of_read_number(range + 1, na - 1);
 327         s  = of_read_number(range + na + pna, ns);
 328         da = of_read_number(addr + 1, na - 1);
 329
 330         pr_debug("OF: ISA map, cp=%llx, s=%llx, da=%llx\n",
 331                  (unsigned long long)cp, (unsigned long long)s,
 332                  (unsigned long long)da);
 333
 334         if (da < cp || da >= (cp + s))
 335                 return OF_BAD_ADDR;
 336         return da - cp;
 337 }
 338
 339 static int of_bus_isa_translate(__be32 *addr, u64 offset, int na)
 340 {
 341         return of_bus_default_translate(addr + 1, offset, na - 1);
 342 }
 343
 344 static unsigned int of_bus_isa_get_flags(const __be32 *addr)
 345 {
 346         unsigned int flags = 0;
 347         u32 w = be32_to_cpup(addr);
 348
 349         if (w & 1)
 350                 flags |= IORESOURCE_IO;
 351         else
 352                 flags |= IORESOURCE_MEM;
 353         return flags;
 354 }
 355
 356 /*
 357  * Array of bus specific translators
 358  */
 359
 360 static struct of_bus of_busses[] = {
 361 #ifdef CONFIG_OF_ADDRESS_PCI
 362         /* PCI */
 363         {
 364                 .name = "pci",
 365                 .addresses = "assigned-addresses",
 366                 .match = of_bus_pci_match,
 367                 .count_cells = of_bus_pci_count_cells,
 368                 .map = of_bus_pci_map,
 369                 .translate = of_bus_pci_translate,
 370                 .get_flags = of_bus_pci_get_flags,
 371         },
 372 #endif /* CONFIG_OF_ADDRESS_PCI */
 373         /* ISA */
 374         {
 375                 .name = "isa",
 376                 .addresses = "reg",
 377                 .match = of_bus_isa_match,
 378                 .count_cells = of_bus_isa_count_cells,
 379                 .map = of_bus_isa_map,
 380                 .translate = of_bus_isa_translate,
 381                 .get_flags = of_bus_isa_get_flags,
 382         },
 383         /* Default */
 384         {
 385                 .name = "default",
 386                 .addresses = "reg",
 387                 .match = NULL,
 388                 .count_cells = of_bus_default_count_cells,
 389                 .map = of_bus_default_map,
 390                 .translate = of_bus_default_translate,
 391                 .get_flags = of_bus_default_get_flags,
 392         },
 393 };
 394
 395 static struct of_bus *of_match_bus(struct device_node *np)
 396 {
 397         int i;
 398
 399         for (i = 0; i < ARRAY_SIZE(of_busses); i++)
 400                 if (!of_busses[i].match || of_busses[i].match(np))
 401                         return &of_busses[i];
 402         BUG();
 403         return NULL;
 404 }
 405
 406 static int of_translate_one(struct device_node *parent, struct of_bus *bus,
 407                             struct of_bus *pbus, __be32 *addr,
 408                             int na, int ns, int pna, const char *rprop)
 409 {
 410         const __be32 *ranges;
 411         unsigned int rlen;
 412         int rone;
 413         u64 offset = OF_BAD_ADDR;
 414
 415         /* Normally, an absence of a "ranges" property means we are
 416          * crossing a non-translatable boundary, and thus the addresses
 417          * below the current not cannot be converted to CPU physical ones.
 418          * Unfortunately, while this is very clear in the spec, it's not
 419          * what Apple understood, and they do have things like /uni-n or
 420          * /ht nodes with no "ranges" property and a lot of perfectly
 421          * useable mapped devices below them. Thus we treat the absence of
 422          * "ranges" as equivalent to an empty "ranges" property which means
 423          * a 1:1 translation at that level. It's up to the caller not to try
 424          * to translate addresses that aren't supposed to be translated in
 425          * the first place. --BenH.
 426          *
 427          * As far as we know, this damage only exists on Apple machines, so
 428          * This code is only enabled on powerpc. --gcl
 429          */
 430         ranges = of_get_property(parent, rprop, &rlen);
 431 #if !defined(CONFIG_PPC)
 432         if (ranges == NULL) {
 433                 pr_err("OF: no ranges; cannot translate\n");
 434                 return 1;
 435         }
 436 #endif /* !defined(CONFIG_PPC) */
 437         if (ranges == NULL || rlen == 0) {
 438                 offset = of_read_number(addr, na);
 439                 memset(addr, 0, pna * 4);
 440                 pr_debug("OF: empty ranges; 1:1 translation\n");
 441                 goto finish;
 442         }
 443
 444         pr_debug("OF: walking ranges...\n");
 445
 446         /* Now walk through the ranges */
 447         rlen /= 4;
 448         rone = na + pna + ns;
 449         for (; rlen >= rone; rlen -= rone, ranges += rone) {
 450                 offset = bus->map(addr, ranges, na, ns, pna);
 451                 if (offset != OF_BAD_ADDR)
 452                         break;
 453         }
 454         if (offset == OF_BAD_ADDR) {
 455                 pr_debug("OF: not found !\n");
 456                 return 1;
 457         }
 458         memcpy(addr, ranges + na, 4 * pna);
 459
 460  finish:
 461         of_dump_addr("OF: parent translation for:", addr, pna);
 462         pr_debug("OF: with offset: %llx\n", (unsigned long long)offset);
 463
 464         /* Translate it into parent bus space */
 465         return pbus->translate(addr, offset, pna);
 466 }
 467
 468 /*
 469  * Translate an address from the device-tree into a CPU physical address,
 470  * this walks up the tree and applies the various bus mappings on the
 471  * way.
 472  *
 473  * Note: We consider that crossing any level with #size-cells == 0 to mean
 474  * that translation is impossible (that is we are not dealing with a value
 475  * that can be mapped to a cpu physical address). This is not really specified
 476  * that way, but this is traditionally the way IBM at least do things
 477  */
 478 static u64 __of_translate_address(struct device_node *dev,
 479                                   const __be32 *in_addr, const char *rprop)
 480 {
 481         struct device_node *parent = NULL;
 482         struct of_bus *bus, *pbus;
 483         __be32 addr[OF_MAX_ADDR_CELLS];
 484         int na, ns, pna, pns;
 485         u64 result = OF_BAD_ADDR;
 486
 487         pr_debug("OF: ** translation for device %s **\n", of_node_full_name(dev));
 488
 489         /* Increase refcount at current level */
 490         of_node_get(dev);
 491
 492         /* Get parent & match bus type */
 493         parent = of_get_parent(dev);
 494         if (parent == NULL)
 495                 goto bail;
 496         bus = of_match_bus(parent);
 497
 498         /* Count address cells & copy address locally */
 499         bus->count_cells(dev, &na, &ns);
 500         if (!OF_CHECK_COUNTS(na, ns)) {
 501                 printk(KERN_ERR "prom_parse: Bad cell count for %s\n",
 502                        of_node_full_name(dev));
 503                 goto bail;
 504         }
 505         memcpy(addr, in_addr, na * 4);
 506
 507         pr_debug("OF: bus is %s (na=%d, ns=%d) on %s\n",
 508             bus->name, na, ns, of_node_full_name(parent));
 509         of_dump_addr("OF: translating address:", addr, na);
 510
 511         /* Translate */
 512         for (;;) {
 513                 /* Switch to parent bus */
 514                 of_node_put(dev);
 515                 dev = parent;
 516                 parent = of_get_parent(dev);
 517
 518                 /* If root, we have finished */
 519                 if (parent == NULL) {
 520                         pr_debug("OF: reached root node\n");
 521                         result = of_read_number(addr, na);
 522                         break;
 523                 }
 524
 525                 /* Get new parent bus and counts */
 526                 pbus = of_match_bus(parent);
 527                 pbus->count_cells(dev, &pna, &pns);
 528                 if (!OF_CHECK_COUNTS(pna, pns)) {
 529                         printk(KERN_ERR "prom_parse: Bad cell count for %s\n",
 530                                of_node_full_name(dev));
 531                         break;
 532                 }
 533
 534                 pr_debug("OF: parent bus is %s (na=%d, ns=%d) on %s\n",
 535                     pbus->name, pna, pns, of_node_full_name(parent));
 536
 537                 /* Apply bus translation */
 538                 if (of_translate_one(dev, bus, pbus, addr, na, ns, pna, rprop))
 539                         break;
 540
 541                 /* Complete the move up one level */
 542                 na = pna;
 543                 ns = pns;
 544                 bus = pbus;
 545
 546                 of_dump_addr("OF: one level translation:", addr, na);
 547         }
 548  bail:
 549         of_node_put(parent);
 550         of_node_put(dev);
 551
 552         return result;
 553 }
 554
 555 u64 of_translate_address(struct device_node *dev, const __be32 *in_addr)
 556 {
 557         return __of_translate_address(dev, in_addr, "ranges");
 558 }
 559 EXPORT_SYMBOL(of_translate_address);
 560
 561 u64 of_translate_dma_address(struct device_node *dev, const __be32 *in_addr)
 562 {
 563         return __of_translate_address(dev, in_addr, "dma-ranges");
 564 }
 565 EXPORT_SYMBOL(of_translate_dma_address);
 566
 567 bool of_can_translate_address(struct device_node *dev)
 568 {
 569         struct device_node *parent;
 570         struct of_bus *bus;
 571         int na, ns;
 572
 573         parent = of_get_parent(dev);
 574         if (parent == NULL)
 575                 return false;
 576
 577         bus = of_match_bus(parent);
 578         bus->count_cells(dev, &na, &ns);
 579
 580         of_node_put(parent);
 581
 582         return OF_CHECK_COUNTS(na, ns);
 583 }
 584 EXPORT_SYMBOL(of_can_translate_address);
 585
 586 const __be32 *of_get_address(struct device_node *dev, int index, u64 *size,
 587                     unsigned int *flags)
 588 {
 589         const __be32 *prop;
 590         unsigned int psize;
 591         struct device_node *parent;
 592         struct of_bus *bus;
 593         int onesize, i, na, ns;
 594
 595         /* Get parent & match bus type */
 596         parent = of_get_parent(dev);
 597         if (parent == NULL)
 598                 return NULL;
 599         bus = of_match_bus(parent);
 600         bus->count_cells(dev, &na, &ns);
 601         of_node_put(parent);
 602         if (!OF_CHECK_ADDR_COUNT(na))
 603                 return NULL;
 604
 605         /* Get "reg" or "assigned-addresses" property */
 606         prop = of_get_property(dev, bus->addresses, &psize);
 607         if (prop == NULL)
 608                 return NULL;
 609         psize /= 4;
 610
 611         onesize = na + ns;
 612         for (i = 0; psize >= onesize; psize -= onesize, prop += onesize, i++)
 613                 if (i == index) {
 614                         if (size)
 615                                 *size = of_read_number(prop + na, ns);
 616                         if (flags)
 617                                 *flags = bus->get_flags(prop);
 618                         return prop;
 619                 }
 620         return NULL;
 621 }
 622 EXPORT_SYMBOL(of_get_address);
 623
 624 unsigned long __weak pci_address_to_pio(phys_addr_t address)
 625 {
 626         if (address > IO_SPACE_LIMIT)
 627                 return (unsigned long)-1;
 628
 629         return (unsigned long) address;
 630 }
 631
 632 static int __of_address_to_resource(struct device_node *dev,
 633                 const __be32 *addrp, u64 size, unsigned int flags,
 634                 const char *name, struct resource *r)
 635 {
 636         u64 taddr;
 637
 638         if ((flags & (IORESOURCE_IO | IORESOURCE_MEM)) == 0)
 639                 return -EINVAL;
 640         taddr = of_translate_address(dev, addrp);
 641         if (taddr == OF_BAD_ADDR)
 642                 return -EINVAL;
 643         memset(r, 0, sizeof(struct resource));
 644         if (flags & IORESOURCE_IO) {
 645                 unsigned long port;
 646                 port = pci_address_to_pio(taddr);
 647                 if (port == (unsigned long)-1)
 648                         return -EINVAL;
 649                 r->start = port;
 650                 r->end = port + size - 1;
 651         } else {
 652                 r->start = taddr;
 653                 r->end = taddr + size - 1;
 654         }
 655         r->flags = flags;
 656         r->name = name ? name : dev->full_name;
 657
 658         return 0;
 659 }
 660
 661 /**
 662  * of_address_to_resource - Translate device tree address and return as resource
 663  *
 664  * Note that if your address is a PIO address, the conversion will fail if
 665  * the physical address can't be internally converted to an IO token with
 666  * pci_address_to_pio(), that is because it's either called to early or it
 667  * can't be matched to any host bridge IO space
 668  */
 669 int of_address_to_resource(struct device_node *dev, int index,
 670                            struct resource *r)
 671 {
 672         const __be32    *addrp;
 673         u64             size;
 674         unsigned int    flags;
 675         const char      *name = NULL;
 676
 677         addrp = of_get_address(dev, index, &size, &flags);
 678         if (addrp == NULL)
 679                 return -EINVAL;
 680
 681         /* Get optional "reg-names" property to add a name to a resource */
 682         of_property_read_string_index(dev, "reg-names", index, &name);
 683
 684         return __of_address_to_resource(dev, addrp, size, flags, name, r);
 685 }
 686 EXPORT_SYMBOL_GPL(of_address_to_resource);
 687
 688 struct device_node *of_find_matching_node_by_address(struct device_node *from,
 689                                         const struct of_device_id *matches,
 690                                         u64 base_address)
 691 {
 692         struct device_node *dn = of_find_matching_node(from, matches);
 693         struct resource res;
 694
 695         while (dn) {
 696                 if (of_address_to_resource(dn, 0, &res))
 697                         continue;
 698                 if (res.start == base_address)
 699                         return dn;
 700                 dn = of_find_matching_node(dn, matches);
 701         }
 702
 703         return NULL;
 704 }
 705
 706
 707 /**
 708  * of_iomap - Maps the memory mapped IO for a given device_node
 709  * @device:     the device whose io range will be mapped
 710  * @index:      index of the io range
 711  *
 712  * Returns a pointer to the mapped memory
 713  */
 714 void __iomem *of_iomap(struct device_node *np, int index)
 715 {
 716         struct resource res;
 717
 718         if (of_address_to_resource(np, index, &res))
 719                 return NULL;
 720
 721         return ioremap(res.start, resource_size(&res));
 722 }
 723 EXPORT_SYMBOL(of_iomap);