text: 
  #include <linux/io.h>
  #include <linux/ioport.h>
  #include <linux/module.h>
  #include <linux/of_address.h>
  #include <linux/pci_regs.h>
  #include <linux/string.h>
  
  /* Max address size we deal with */
  #define OF_MAX_ADDR_CELLS	4
  #define OF_CHECK_COUNTS(na, ns)	((na) > 0 && (na) <= OF_MAX_ADDR_CELLS && \
  			(ns) > 0)
  
  static struct of_bus *of_match_bus(struct device_node *np);
  static int __of_address_to_resource(struct device_node *dev,
  		const __be32 *addrp, u64 size, unsigned int flags,
  		const char *name, struct resource *r);
  
  /* Debug utility */
  #ifdef DEBUG
  static void of_dump_addr(const char *s, const __be32 *addr, int na)
  {
  	printk(KERN_DEBUG "%s", s);
  	while (na--)
  		printk(" %08x", be32_to_cpu(*(addr++)));
  	printk("\n");
  }
  #else
  static void of_dump_addr(const char *s, const __be32 *addr, int na) { }
  #endif
  
  /* Callbacks for bus specific translators */
  struct of_bus {
  	const char	*name;
  	const char	*addresses;
  	int		(*match)(struct device_node *parent);
  	void		(*count_cells)(struct device_node *child,
  				       int *addrc, int *sizec);
  	u64		(*map)(u32 *addr, const __be32 *range,
  				int na, int ns, int pna);
  	int		(*translate)(u32 *addr, u64 offset, int na);
  	unsigned int	(*get_flags)(const __be32 *addr);
  };
  
  /*
   * Default translator (generic bus)
   */
  
  static void of_bus_default_count_cells(struct device_node *dev,
  				       int *addrc, int *sizec)
  {
  	if (addrc)
  		*addrc = of_n_addr_cells(dev);
  	if (sizec)
  		*sizec = of_n_size_cells(dev);
  }
  
  static u64 of_bus_default_map(u32 *addr, const __be32 *range,
  		int na, int ns, int pna)
  {
  	u64 cp, s, da;
  
  	cp = of_read_number(range, na);
  	s  = of_read_number(range + na + pna, ns);
  	da = of_read_number(addr, na);
  
  	pr_debug("OF: default map, cp=%llx, s=%llx, da=%llx\n",
  		 (unsigned long long)cp, (unsigned long long)s,
  		 (unsigned long long)da);
  
  	if (da < cp || da >= (cp + s))
  		return OF_BAD_ADDR;
  	return da - cp;
  }
  
  static int of_bus_default_translate(u32 *addr, u64 offset, int na)
  {
  	u64 a = of_read_number(addr, na);
  	memset(addr, 0, na * 4);
  	a += offset;
  	if (na > 1)
  		addr[na - 2] = cpu_to_be32(a >> 32);
  	addr[na - 1] = cpu_to_be32(a & 0xffffffffu);
  
  	return 0;
  }
  
  static unsigned int of_bus_default_get_flags(const __be32 *addr)
  {
  	return IORESOURCE_MEM;
  }
  
  #ifdef CONFIG_PCI
  /*
   * PCI bus specific translator
   */
  
  static int of_bus_pci_match(struct device_node *np)
  {
  	/* "vci" is for the /chaos bridge on 1st-gen PCI powermacs */
  	return !strcmp(np->type, "pci") || !strcmp(np->type, "vci");
  }
  
  static void of_bus_pci_count_cells(struct device_node *np,
  				   int *addrc, int *sizec)
  {
  	if (addrc)
  		*addrc = 3;
  	if (sizec)
  		*sizec = 2;
  }
  
  static unsigned int of_bus_pci_get_flags(const __be32 *addr)
  {
  	unsigned int flags = 0;
  	u32 w = be32_to_cpup(addr);
  
  	switch((w >> 24) & 0x03) {
  	case 0x01:
  		flags |= IORESOURCE_IO;
  		break;
  	case 0x02: /* 32 bits */
  	case 0x03: /* 64 bits */
  		flags |= IORESOURCE_MEM;
  		break;
  	}
  	if (w & 0x40000000)
  		flags |= IORESOURCE_PREFETCH;
  	return flags;
  }
  
  static u64 of_bus_pci_map(u32 *addr, const __be32 *range, int na, int ns,
  		int pna)
  {
  	u64 cp, s, da;
  	unsigned int af, rf;
  
  	af = of_bus_pci_get_flags(addr);
  	rf = of_bus_pci_get_flags(range);
  
  	/* Check address type match */
  	if ((af ^ rf) & (IORESOURCE_MEM | IORESOURCE_IO))
  		return OF_BAD_ADDR;
  
  	/* Read address values, skipping high cell */
  	cp = of_read_number(range + 1, na - 1);
  	s  = of_read_number(range + na + pna, ns);
  	da = of_read_number(addr + 1, na - 1);
  
  	pr_debug("OF: PCI map, cp=%llx, s=%llx, da=%llx\n",
  		 (unsigned long long)cp, (unsigned long long)s,
  		 (unsigned long long)da);
  
  	if (da < cp || da >= (cp + s))
  		return OF_BAD_ADDR;
  	return da - cp;
  }
  
  static int of_bus_pci_translate(u32 *addr, u64 offset, int na)
  {
  	return of_bus_default_translate(addr + 1, offset, na - 1);
  }
  
  const __be32 *of_get_pci_address(struct device_node *dev, int bar_no, u64 *size,
  			unsigned int *flags)
  {
  	const __be32 *prop;
  	unsigned int psize;
  	struct device_node *parent;
  	struct of_bus *bus;
  	int onesize, i, na, ns;
  
  	/* Get parent & match bus type */
  	parent = of_get_parent(dev);
  	if (parent == NULL)
  		return NULL;
  	bus = of_match_bus(parent);
  	if (strcmp(bus->name, "pci")) {
  		of_node_put(parent);
  		return NULL;
  	}
  	bus->count_cells(dev, &na, &ns);
  	of_node_put(parent);
  	if (!OF_CHECK_COUNTS(na, ns))
  		return NULL;
  
  	/* Get "reg" or "assigned-addresses" property */
  	prop = of_get_property(dev, bus->addresses, &psize);
  	if (prop == NULL)
  		return NULL;
  	psize /= 4;
  
  	onesize = na + ns;
  	for (i = 0; psize >= onesize; psize -= onesize, prop += onesize, i++) {
  		u32 val = be32_to_cpu(prop[0]);
  		if ((val & 0xff) == ((bar_no * 4) + PCI_BASE_ADDRESS_0)) {
  			if (size)
  				*size = of_read_number(prop + na, ns);
  			if (flags)
  				*flags = bus->get_flags(prop);
  			return prop;
  		}
  	}
  	return NULL;
  }
  EXPORT_SYMBOL(of_get_pci_address);
  
  int of_pci_address_to_resource(struct device_node *dev, int bar,
  			       struct resource *r)
  {
  	const __be32	*addrp;
  	u64		size;
  	unsigned int	flags;
  
  	addrp = of_get_pci_address(dev, bar, &size, &flags);
  	if (addrp == NULL)
  		return -EINVAL;
  	return __of_address_to_resource(dev, addrp, size, flags, NULL, r);
  }
  EXPORT_SYMBOL_GPL(of_pci_address_to_resource);
  #endif /* CONFIG_PCI */
  
  /*
   * ISA bus specific translator
   */
  
  static int of_bus_isa_match(struct device_node *np)
  {
  	return !strcmp(np->name, "isa");
  }
  
  static void of_bus_isa_count_cells(struct device_node *child,
  				   int *addrc, int *sizec)
  {
  	if (addrc)
  		*addrc = 2;
  	if (sizec)
  		*sizec = 1;
  }
  
  static u64 of_bus_isa_map(u32 *addr, const __be32 *range, int na, int ns,
  		int pna)
  {
  	u64 cp, s, da;
  
  	/* Check address type match */
  	if ((addr[0] ^ range[0]) & cpu_to_be32(1))
  		return OF_BAD_ADDR;
  
  	/* Read address values, skipping high cell */
  	cp = of_read_number(range + 1, na - 1);
  	s  = of_read_number(range + na + pna, ns);
  	da = of_read_number(addr + 1, na - 1);
  
  	pr_debug("OF: ISA map, cp=%llx, s=%llx, da=%llx\n",
  		 (unsigned long long)cp, (unsigned long long)s,
  		 (unsigned long long)da);
  
  	if (da < cp || da >= (cp + s))
  		return OF_BAD_ADDR;
  	return da - cp;
  }
  
  static int of_bus_isa_translate(u32 *addr, u64 offset, int na)
  {
  	return of_bus_default_translate(addr + 1, offset, na - 1);
  }
  
  static unsigned int of_bus_isa_get_flags(const __be32 *addr)
  {
  	unsigned int flags = 0;
  	u32 w = be32_to_cpup(addr);
  
  	if (w & 1)
  		flags |= IORESOURCE_IO;
  	else
  		flags |= IORESOURCE_MEM;
  	return flags;
  }
  
  /*
   * Array of bus specific translators
   */
  
  static struct of_bus of_busses[] = {
  #ifdef CONFIG_PCI
  	/* PCI */
  	{
  		.name = "pci",
  		.addresses = "assigned-addresses",
  		.match = of_bus_pci_match,
  		.count_cells = of_bus_pci_count_cells,
  		.map = of_bus_pci_map,
  		.translate = of_bus_pci_translate,
  		.get_flags = of_bus_pci_get_flags,
  	},
  #endif /* CONFIG_PCI */
  	/* ISA */
  	{
  		.name = "isa",
  		.addresses = "reg",
  		.match = of_bus_isa_match,
  		.count_cells = of_bus_isa_count_cells,
  		.map = of_bus_isa_map,
  		.translate = of_bus_isa_translate,
  		.get_flags = of_bus_isa_get_flags,
  	},
  	/* Default */
  	{
  		.name = "default",
  		.addresses = "reg",
  		.match = NULL,
  		.count_cells = of_bus_default_count_cells,
  		.map = of_bus_default_map,
  		.translate = of_bus_default_translate,
  		.get_flags = of_bus_default_get_flags,
  	},
  };
  
  static struct of_bus *of_match_bus(struct device_node *np)
  {
  	int i;
  
  	for (i = 0; i < ARRAY_SIZE(of_busses); i++)
  		if (!of_busses[i].match || of_busses[i].match(np))
  			return &of_busses[i];
  	BUG();
  	return NULL;
  }
  
  static int of_translate_one(struct device_node *parent, struct of_bus *bus,
  			    struct of_bus *pbus, u32 *addr,
  			    int na, int ns, int pna, const char *rprop)
  {
  	const __be32 *ranges;
  	unsigned int rlen;
  	int rone;
  	u64 offset = OF_BAD_ADDR;
  
  	/* Normally, an absence of a "ranges" property means we are
  	 * crossing a non-translatable boundary, and thus the addresses
  	 * below the current not cannot be converted to CPU physical ones.
  	 * Unfortunately, while this is very clear in the spec, it's not
  	 * what Apple understood, and they do have things like /uni-n or
  	 * /ht nodes with no "ranges" property and a lot of perfectly
  	 * useable mapped devices below them. Thus we treat the absence of
  	 * "ranges" as equivalent to an empty "ranges" property which means
  	 * a 1:1 translation at that level. It's up to the caller not to try
  	 * to translate addresses that aren't supposed to be translated in
  	 * the first place. --BenH.
  	 *
  	 * As far as we know, this damage only exists on Apple machines, so
  	 * This code is only enabled on powerpc. --gcl
  	 */
  	ranges = of_get_property(parent, rprop, &rlen);
  #if !defined(CONFIG_PPC)
  	if (ranges == NULL) {
  		pr_err("OF: no ranges; cannot translate\n");
  		return 1;
  	}
  #endif /* !defined(CONFIG_PPC) */
  	if (ranges == NULL || rlen == 0) {
  		offset = of_read_number(addr, na);
  		memset(addr, 0, pna * 4);
  		pr_debug("OF: empty ranges; 1:1 translation\n");
  		goto finish;
  	}
  
  	pr_debug("OF: walking ranges...\n");
  
  	/* Now walk through the ranges */
  	rlen /= 4;
  	rone = na + pna + ns;
  	for (; rlen >= rone; rlen -= rone, ranges += rone) {
  		offset = bus->map(addr, ranges, na, ns, pna);
  		if (offset != OF_BAD_ADDR)
  			break;
  	}
  	if (offset == OF_BAD_ADDR) {
  		pr_debug("OF: not found !\n");
  		return 1;
  	}
  	memcpy(addr, ranges + na, 4 * pna);
  
   finish:
  	of_dump_addr("OF: parent translation for:", addr, pna);
  	pr_debug("OF: with offset: %llx\n", (unsigned long long)offset);
  
  	/* Translate it into parent bus space */
  	return pbus->translate(addr, offset, pna);
  }
  
  /*
   * Translate an address from the device-tree into a CPU physical address,
   * this walks up the tree and applies the various bus mappings on the
   * way.
   *
   * Note: We consider that crossing any level with #size-cells == 0 to mean
   * that translation is impossible (that is we are not dealing with a value
   * that can be mapped to a cpu physical address). This is not really specified
   * that way, but this is traditionally the way IBM at least do things
   */
  u64 __of_translate_address(struct device_node *dev, const __be32 *in_addr,
  			   const char *rprop)
  {
  	struct device_node *parent = NULL;
  	struct of_bus *bus, *pbus;
  	u32 addr[OF_MAX_ADDR_CELLS];
  	int na, ns, pna, pns;
  	u64 result = OF_BAD_ADDR;
  
  	pr_debug("OF: ** translation for device %s **\n", dev->full_name);
  
  	/* Increase refcount at current level */
  	of_node_get(dev);
  
  	/* Get parent & match bus type */
  	parent = of_get_parent(dev);
  	if (parent == NULL)
  		goto bail;
  	bus = of_match_bus(parent);
  
  	/* Cound address cells & copy address locally */
  	bus->count_cells(dev, &na, &ns);
  	if (!OF_CHECK_COUNTS(na, ns)) {
  		printk(KERN_ERR "prom_parse: Bad cell count for %s\n",
  		       dev->full_name);
  		goto bail;
  	}
  	memcpy(addr, in_addr, na * 4);
  
  	pr_debug("OF: bus is %s (na=%d, ns=%d) on %s\n",
  	    bus->name, na, ns, parent->full_name);
  	of_dump_addr("OF: translating address:", addr, na);
  
  	/* Translate */
  	for (;;) {
  		/* Switch to parent bus */
  		of_node_put(dev);
  		dev = parent;
  		parent = of_get_parent(dev);
  
  		/* If root, we have finished */
  		if (parent == NULL) {
  			pr_debug("OF: reached root node\n");
  			result = of_read_number(addr, na);
  			break;
  		}
  
  		/* Get new parent bus and counts */
  		pbus = of_match_bus(parent);
  		pbus->count_cells(dev, &pna, &pns);
  		if (!OF_CHECK_COUNTS(pna, pns)) {
  			printk(KERN_ERR "prom_parse: Bad cell count for %s\n",
  			       dev->full_name);
  			break;
  		}
  
  		pr_debug("OF: parent bus is %s (na=%d, ns=%d) on %s\n",
  		    pbus->name, pna, pns, parent->full_name);
  
  		/* Apply bus translation */
  		if (of_translate_one(dev, bus, pbus, addr, na, ns, pna, rprop))
  			break;
  
  		/* Complete the move up one level */
  		na = pna;
  		ns = pns;
  		bus = pbus;
  
  		of_dump_addr("OF: one level translation:", addr, na);
  	}
   bail:
  	of_node_put(parent);
  	of_node_put(dev);
  
  	return result;
  }
  
  u64 of_translate_address(struct device_node *dev, const __be32 *in_addr)
  {
  	return __of_translate_address(dev, in_addr, "ranges");
  }
  EXPORT_SYMBOL(of_translate_address);
  
  u64 of_translate_dma_address(struct device_node *dev, const __be32 *in_addr)
  {
  	return __of_translate_address(dev, in_addr, "dma-ranges");
  }
  EXPORT_SYMBOL(of_translate_dma_address);
  
  const __be32 *of_get_address(struct device_node *dev, int index, u64 *size,
  		    unsigned int *flags)
  {
  	const __be32 *prop;
  	unsigned int psize;
  	struct device_node *parent;
  	struct of_bus *bus;
  	int onesize, i, na, ns;
  
  	/* Get parent & match bus type */
  	parent = of_get_parent(dev);
  	if (parent == NULL)
  		return NULL;
  	bus = of_match_bus(parent);
  	bus->count_cells(dev, &na, &ns);
  	of_node_put(parent);
  	if (!OF_CHECK_COUNTS(na, ns))
  		return NULL;
  
  	/* Get "reg" or "assigned-addresses" property */
  	prop = of_get_property(dev, bus->addresses, &psize);
  	if (prop == NULL)
  		return NULL;
  	psize /= 4;
  
  	onesize = na + ns;
  	for (i = 0; psize >= onesize; psize -= onesize, prop += onesize, i++)
  		if (i == index) {
  			if (size)
  				*size = of_read_number(prop + na, ns);
  			if (flags)
  				*flags = bus->get_flags(prop);
  			return prop;
  		}
  	return NULL;
  }
  EXPORT_SYMBOL(of_get_address);
  
  static int __of_address_to_resource(struct device_node *dev,
  		const __be32 *addrp, u64 size, unsigned int flags,
  		const char *name, struct resource *r)
  {
  	u64 taddr;
  
  	if ((flags & (IORESOURCE_IO | IORESOURCE_MEM)) == 0)
  		return -EINVAL;
  	taddr = of_translate_address(dev, addrp);
  	if (taddr == OF_BAD_ADDR)
  		return -EINVAL;
  	memset(r, 0, sizeof(struct resource));
  	if (flags & IORESOURCE_IO) {
  		unsigned long port;
  		port = pci_address_to_pio(taddr);
  		if (port == (unsigned long)-1)
  			return -EINVAL;
  		r->start = port;
  		r->end = port + size - 1;
  	} else {
  		r->start = taddr;
  		r->end = taddr + size - 1;
  	}
  	r->flags = flags;
  	r->name = name ? name : dev->full_name;
  
  	return 0;
  }
  
  /**
   * of_address_to_resource - Translate device tree address and return as resource
   *
   * Note that if your address is a PIO address, the conversion will fail if
   * the physical address can't be internally converted to an IO token with
   * pci_address_to_pio(), that is because it's either called to early or it
   * can't be matched to any host bridge IO space
   */
  int of_address_to_resource(struct device_node *dev, int index,
  			   struct resource *r)
  {
  	const __be32	*addrp;
  	u64		size;
  	unsigned int	flags;
  	const char	*name = NULL;
  
  	addrp = of_get_address(dev, index, &size, &flags);
  	if (addrp == NULL)
  		return -EINVAL;
  
  	/* Get optional "reg-names" property to add a name to a resource */
  	of_property_read_string_index(dev, "reg-names",	index, &name);
  
  	return __of_address_to_resource(dev, addrp, size, flags, name, r);
  }
  EXPORT_SYMBOL_GPL(of_address_to_resource);
  
  struct device_node *of_find_matching_node_by_address(struct device_node *from,
  					const struct of_device_id *matches,
  					u64 base_address)
  {
  	struct device_node *dn = of_find_matching_node(from, matches);
  	struct resource res;
  
  	while (dn) {
  		if (of_address_to_resource(dn, 0, &res))
  			continue;
  		if (res.start == base_address)
  			return dn;
  		dn = of_find_matching_node(dn, matches);
  	}
  
  	return NULL;
  }
  
  
  /**
   * of_iomap - Maps the memory mapped IO for a given device_node
   * @device:	the device whose io range will be mapped
   * @index:	index of the io range
   *
   * Returns a pointer to the mapped memory
   */
  void __iomem *of_iomap(struct device_node *np, int index)
  {
  	struct resource res;
  
  	if (of_address_to_resource(np, index, &res))
  		return NULL;
  
  	return ioremap(res.start, resource_size(&res));
  }
  EXPORT_SYMBOL(of_iomap);
  