/*
   * Functions for working with the Flattened Device Tree data format
   *
   * Copyright 2009 Benjamin Herrenschmidt, IBM Corp
   * benh@kernel.crashing.org
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * version 2 as published by the Free Software Foundation.
   */

  #include <linux/kernel.h>

  #include <linux/initrd.h>

  #include <linux/module.h>

  #include <linux/of.h>
  #include <linux/of_fdt.h>

  #include <linux/string.h>
  #include <linux/errno.h>

  #include <linux/slab.h>

  #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */

  #ifdef CONFIG_PPC
  #include <asm/machdep.h>
  #endif /* CONFIG_PPC */

  #include <asm/setup.h>

  #include <asm/page.h>

  char *of_fdt_get_string(struct boot_param_header *blob, u32 offset)
  {
  	return ((char *)blob) +
  		be32_to_cpu(blob->off_dt_strings) + offset;
  }
  
  /**
   * of_fdt_get_property - Given a node in the given flat blob, return
   * the property ptr
   */
  void *of_fdt_get_property(struct boot_param_header *blob,
  		       unsigned long node, const char *name,
  		       unsigned long *size)
  {
  	unsigned long p = node;
  
  	do {
  		u32 tag = be32_to_cpup((__be32 *)p);
  		u32 sz, noff;
  		const char *nstr;
  
  		p += 4;
  		if (tag == OF_DT_NOP)
  			continue;
  		if (tag != OF_DT_PROP)
  			return NULL;
  
  		sz = be32_to_cpup((__be32 *)p);
  		noff = be32_to_cpup((__be32 *)(p + 4));
  		p += 8;
  		if (be32_to_cpu(blob->version) < 0x10)
  			p = ALIGN(p, sz >= 8 ? 8 : 4);
  
  		nstr = of_fdt_get_string(blob, noff);
  		if (nstr == NULL) {
  			pr_warning("Can't find property index name !
  ");
  			return NULL;
  		}
  		if (strcmp(name, nstr) == 0) {
  			if (size)
  				*size = sz;
  			return (void *)p;
  		}
  		p += sz;
  		p = ALIGN(p, 4);
  	} while (1);
  }
  
  /**
   * of_fdt_is_compatible - Return true if given node from the given blob has
   * compat in its compatible list
   * @blob: A device tree blob
   * @node: node to test
   * @compat: compatible string to compare with compatible list.

   *
   * On match, returns a non-zero value with smaller values returned for more
   * specific compatible values.

   */
  int of_fdt_is_compatible(struct boot_param_header *blob,
  		      unsigned long node, const char *compat)
  {
  	const char *cp;

  	unsigned long cplen, l, score = 0;

  
  	cp = of_fdt_get_property(blob, node, "compatible", &cplen);
  	if (cp == NULL)
  		return 0;
  	while (cplen > 0) {

  		score++;

  		if (of_compat_cmp(cp, compat, strlen(compat)) == 0)

  			return score;

  		l = strlen(cp) + 1;
  		cp += l;
  		cplen -= l;
  	}
  
  	return 0;
  }

  /**
   * of_fdt_match - Return true if node matches a list of compatible values
   */
  int of_fdt_match(struct boot_param_header *blob, unsigned long node,

                   const char *const *compat)

  {
  	unsigned int tmp, score = 0;
  
  	if (!compat)
  		return 0;
  
  	while (*compat) {
  		tmp = of_fdt_is_compatible(blob, node, *compat);
  		if (tmp && (score == 0 || (tmp < score)))
  			score = tmp;
  		compat++;
  	}
  
  	return score;
  }

  static void *unflatten_dt_alloc(unsigned long *mem, unsigned long size,

  				       unsigned long align)
  {
  	void *res;

  	*mem = ALIGN(*mem, align);

  	res = (void *)*mem;
  	*mem += size;
  
  	return res;
  }
  
  /**
   * unflatten_dt_node - Alloc and populate a device_node from the flat tree

   * @blob: The parent device tree blob

   * @mem: Memory chunk to use for allocating device nodes and properties

   * @p: pointer to node in flat tree
   * @dad: Parent struct device_node
   * @allnextpp: pointer to ->allnext from last allocated device_node
   * @fpsize: Size of the node path up at the current depth.
   */

  static unsigned long unflatten_dt_node(struct boot_param_header *blob,

  				unsigned long mem,
  				unsigned long *p,
  				struct device_node *dad,
  				struct device_node ***allnextpp,
  				unsigned long fpsize)

  {
  	struct device_node *np;
  	struct property *pp, **prev_pp = NULL;
  	char *pathp;
  	u32 tag;
  	unsigned int l, allocl;
  	int has_name = 0;
  	int new_format = 0;

  	tag = be32_to_cpup((__be32 *)(*p));

  	if (tag != OF_DT_BEGIN_NODE) {
  		pr_err("Weird tag at start of node: %x
  ", tag);
  		return mem;
  	}
  	*p += 4;
  	pathp = (char *)*p;
  	l = allocl = strlen(pathp) + 1;

  	*p = ALIGN(*p + l, 4);

  
  	/* version 0x10 has a more compact unit name here instead of the full
  	 * path. we accumulate the full path size using "fpsize", we'll rebuild
  	 * it later. We detect this because the first character of the name is
  	 * not '/'.
  	 */
  	if ((*pathp) != '/') {
  		new_format = 1;
  		if (fpsize == 0) {
  			/* root node: special case. fpsize accounts for path
  			 * plus terminating zero. root node only has '/', so
  			 * fpsize should be 2, but we want to avoid the first
  			 * level nodes to have two '/' so we use fpsize 1 here
  			 */
  			fpsize = 1;
  			allocl = 2;
  		} else {
  			/* account for '/' and path size minus terminal 0
  			 * already in 'l'
  			 */
  			fpsize += l;
  			allocl = fpsize;
  		}
  	}
  
  	np = unflatten_dt_alloc(&mem, sizeof(struct device_node) + allocl,
  				__alignof__(struct device_node));
  	if (allnextpp) {
  		memset(np, 0, sizeof(*np));
  		np->full_name = ((char *)np) + sizeof(struct device_node);
  		if (new_format) {
  			char *fn = np->full_name;
  			/* rebuild full path for new format */
  			if (dad && dad->parent) {
  				strcpy(fn, dad->full_name);
  #ifdef DEBUG
  				if ((strlen(fn) + l + 1) != allocl) {
  					pr_debug("%s: p: %d, l: %d, a: %d
  ",
  						pathp, (int)strlen(fn),
  						l, allocl);
  				}
  #endif
  				fn += strlen(fn);
  			}
  			*(fn++) = '/';
  			memcpy(fn, pathp, l);
  		} else
  			memcpy(np->full_name, pathp, l);
  		prev_pp = &np->properties;
  		**allnextpp = np;
  		*allnextpp = &np->allnext;
  		if (dad != NULL) {
  			np->parent = dad;
  			/* we temporarily use the next field as `last_child'*/
  			if (dad->next == NULL)
  				dad->child = np;
  			else
  				dad->next->sibling = np;
  			dad->next = np;
  		}
  		kref_init(&np->kref);
  	}

  	/* process properties */

  	while (1) {
  		u32 sz, noff;
  		char *pname;

  		tag = be32_to_cpup((__be32 *)(*p));

  		if (tag == OF_DT_NOP) {
  			*p += 4;
  			continue;
  		}
  		if (tag != OF_DT_PROP)
  			break;
  		*p += 4;

  		sz = be32_to_cpup((__be32 *)(*p));
  		noff = be32_to_cpup((__be32 *)((*p) + 4));

  		*p += 8;

  		if (be32_to_cpu(blob->version) < 0x10)

  			*p = ALIGN(*p, sz >= 8 ? 8 : 4);

  		pname = of_fdt_get_string(blob, noff);

  		if (pname == NULL) {
  			pr_info("Can't find property name in list !
  ");
  			break;
  		}
  		if (strcmp(pname, "name") == 0)
  			has_name = 1;
  		l = strlen(pname) + 1;
  		pp = unflatten_dt_alloc(&mem, sizeof(struct property),
  					__alignof__(struct property));
  		if (allnextpp) {

  			/* We accept flattened tree phandles either in
  			 * ePAPR-style "phandle" properties, or the
  			 * legacy "linux,phandle" properties.  If both
  			 * appear and have different values, things
  			 * will get weird.  Don't do that. */
  			if ((strcmp(pname, "phandle") == 0) ||
  			    (strcmp(pname, "linux,phandle") == 0)) {

  				if (np->phandle == 0)

  					np->phandle = be32_to_cpup((__be32*)*p);

  			}

  			/* And we process the "ibm,phandle" property
  			 * used in pSeries dynamic device tree
  			 * stuff */

  			if (strcmp(pname, "ibm,phandle") == 0)

  				np->phandle = be32_to_cpup((__be32 *)*p);

  			pp->name = pname;
  			pp->length = sz;
  			pp->value = (void *)*p;
  			*prev_pp = pp;
  			prev_pp = &pp->next;
  		}

  		*p = ALIGN((*p) + sz, 4);

  	}
  	/* with version 0x10 we may not have the name property, recreate
  	 * it here from the unit name if absent
  	 */
  	if (!has_name) {
  		char *p1 = pathp, *ps = pathp, *pa = NULL;
  		int sz;
  
  		while (*p1) {
  			if ((*p1) == '@')
  				pa = p1;
  			if ((*p1) == '/')
  				ps = p1 + 1;
  			p1++;
  		}
  		if (pa < ps)
  			pa = p1;
  		sz = (pa - ps) + 1;
  		pp = unflatten_dt_alloc(&mem, sizeof(struct property) + sz,
  					__alignof__(struct property));
  		if (allnextpp) {
  			pp->name = "name";
  			pp->length = sz;
  			pp->value = pp + 1;
  			*prev_pp = pp;
  			prev_pp = &pp->next;
  			memcpy(pp->value, ps, sz - 1);
  			((char *)pp->value)[sz - 1] = 0;
  			pr_debug("fixed up name for %s -> %s
  ", pathp,
  				(char *)pp->value);
  		}
  	}
  	if (allnextpp) {
  		*prev_pp = NULL;
  		np->name = of_get_property(np, "name", NULL);
  		np->type = of_get_property(np, "device_type", NULL);
  
  		if (!np->name)
  			np->name = "<NULL>";
  		if (!np->type)
  			np->type = "<NULL>";
  	}

  	while (tag == OF_DT_BEGIN_NODE || tag == OF_DT_NOP) {
  		if (tag == OF_DT_NOP)
  			*p += 4;
  		else

  			mem = unflatten_dt_node(blob, mem, p, np, allnextpp,
  						fpsize);

  		tag = be32_to_cpup((__be32 *)(*p));

  	}
  	if (tag != OF_DT_END_NODE) {
  		pr_err("Weird tag at end of node: %x
  ", tag);
  		return mem;
  	}
  	*p += 4;
  	return mem;
  }

  /**
   * __unflatten_device_tree - create tree of device_nodes from flat blob
   *
   * unflattens a device-tree, creating the
   * tree of struct device_node. It also fills the "name" and "type"
   * pointers of the nodes so the normal device-tree walking functions
   * can be used.
   * @blob: The blob to expand
   * @mynodes: The device_node tree created by the call
   * @dt_alloc: An allocator that provides a virtual address to memory
   * for the resulting tree
   */

  static void __unflatten_device_tree(struct boot_param_header *blob,

  			     struct device_node **mynodes,
  			     void * (*dt_alloc)(u64 size, u64 align))
  {
  	unsigned long start, mem, size;
  	struct device_node **allnextp = mynodes;
  
  	pr_debug(" -> unflatten_device_tree()
  ");
  
  	if (!blob) {
  		pr_debug("No device tree pointer
  ");
  		return;
  	}
  
  	pr_debug("Unflattening device tree:
  ");
  	pr_debug("magic: %08x
  ", be32_to_cpu(blob->magic));
  	pr_debug("size: %08x
  ", be32_to_cpu(blob->totalsize));
  	pr_debug("version: %08x
  ", be32_to_cpu(blob->version));
  
  	if (be32_to_cpu(blob->magic) != OF_DT_HEADER) {
  		pr_err("Invalid device tree blob header
  ");
  		return;
  	}
  
  	/* First pass, scan for size */
  	start = ((unsigned long)blob) +
  		be32_to_cpu(blob->off_dt_struct);
  	size = unflatten_dt_node(blob, 0, &start, NULL, NULL, 0);
  	size = (size | 3) + 1;
  
  	pr_debug("  size is %lx, allocating...
  ", size);
  
  	/* Allocate memory for the expanded device tree */
  	mem = (unsigned long)
  		dt_alloc(size + 4, __alignof__(struct device_node));
  
  	((__be32 *)mem)[size / 4] = cpu_to_be32(0xdeadbeef);
  
  	pr_debug("  unflattening %lx...
  ", mem);
  
  	/* Second pass, do actual unflattening */
  	start = ((unsigned long)blob) +
  		be32_to_cpu(blob->off_dt_struct);
  	unflatten_dt_node(blob, mem, &start, NULL, &allnextp, 0);
  	if (be32_to_cpup((__be32 *)start) != OF_DT_END)
  		pr_warning("Weird tag at end of tree: %08x
  ", *((u32 *)start));
  	if (be32_to_cpu(((__be32 *)mem)[size / 4]) != 0xdeadbeef)
  		pr_warning("End of tree marker overwritten: %08x
  ",
  			   be32_to_cpu(((__be32 *)mem)[size / 4]));
  	*allnextp = NULL;
  
  	pr_debug(" <- unflatten_device_tree()
  ");
  }
  
  static void *kernel_tree_alloc(u64 size, u64 align)
  {
  	return kzalloc(size, GFP_KERNEL);
  }
  
  /**
   * of_fdt_unflatten_tree - create tree of device_nodes from flat blob
   *
   * unflattens the device-tree passed by the firmware, creating the
   * tree of struct device_node. It also fills the "name" and "type"
   * pointers of the nodes so the normal device-tree walking functions
   * can be used.
   */
  void of_fdt_unflatten_tree(unsigned long *blob,
  			struct device_node **mynodes)
  {
  	struct boot_param_header *device_tree =
  		(struct boot_param_header *)blob;
  	__unflatten_device_tree(device_tree, mynodes, &kernel_tree_alloc);
  }
  EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree);

  /* Everything below here references initial_boot_params directly. */
  int __initdata dt_root_addr_cells;
  int __initdata dt_root_size_cells;
  
  struct boot_param_header *initial_boot_params;
  
  #ifdef CONFIG_OF_EARLY_FLATTREE
  
  /**
   * of_scan_flat_dt - scan flattened tree blob and call callback on each.
   * @it: callback function
   * @data: context data pointer
   *
   * This function is used to scan the flattened device-tree, it is
   * used to extract the memory information at boot before we can
   * unflatten the tree
   */
  int __init of_scan_flat_dt(int (*it)(unsigned long node,
  				     const char *uname, int depth,
  				     void *data),
  			   void *data)
  {
  	unsigned long p = ((unsigned long)initial_boot_params) +
  		be32_to_cpu(initial_boot_params->off_dt_struct);
  	int rc = 0;
  	int depth = -1;
  
  	do {
  		u32 tag = be32_to_cpup((__be32 *)p);
  		char *pathp;
  
  		p += 4;
  		if (tag == OF_DT_END_NODE) {
  			depth--;
  			continue;
  		}
  		if (tag == OF_DT_NOP)
  			continue;
  		if (tag == OF_DT_END)
  			break;
  		if (tag == OF_DT_PROP) {
  			u32 sz = be32_to_cpup((__be32 *)p);
  			p += 8;
  			if (be32_to_cpu(initial_boot_params->version) < 0x10)
  				p = ALIGN(p, sz >= 8 ? 8 : 4);
  			p += sz;
  			p = ALIGN(p, 4);
  			continue;
  		}
  		if (tag != OF_DT_BEGIN_NODE) {
  			pr_err("Invalid tag %x in flat device tree!
  ", tag);
  			return -EINVAL;
  		}
  		depth++;
  		pathp = (char *)p;
  		p = ALIGN(p + strlen(pathp) + 1, 4);
  		if ((*pathp) == '/') {
  			char *lp, *np;
  			for (lp = NULL, np = pathp; *np; np++)
  				if ((*np) == '/')
  					lp = np+1;
  			if (lp != NULL)
  				pathp = lp;
  		}
  		rc = it(p, pathp, depth, data);
  		if (rc != 0)
  			break;
  	} while (1);
  
  	return rc;
  }
  
  /**
   * of_get_flat_dt_root - find the root node in the flat blob
   */
  unsigned long __init of_get_flat_dt_root(void)
  {
  	unsigned long p = ((unsigned long)initial_boot_params) +
  		be32_to_cpu(initial_boot_params->off_dt_struct);
  
  	while (be32_to_cpup((__be32 *)p) == OF_DT_NOP)
  		p += 4;
  	BUG_ON(be32_to_cpup((__be32 *)p) != OF_DT_BEGIN_NODE);
  	p += 4;
  	return ALIGN(p + strlen((char *)p) + 1, 4);
  }
  
  /**
   * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
   *
   * This function can be used within scan_flattened_dt callback to get
   * access to properties
   */
  void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
  				 unsigned long *size)
  {
  	return of_fdt_get_property(initial_boot_params, node, name, size);
  }
  
  /**
   * of_flat_dt_is_compatible - Return true if given node has compat in compatible list
   * @node: node to test
   * @compat: compatible string to compare with compatible list.
   */
  int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
  {
  	return of_fdt_is_compatible(initial_boot_params, node, compat);
  }

  /**
   * of_flat_dt_match - Return true if node matches a list of compatible values
   */

  int __init of_flat_dt_match(unsigned long node, const char *const *compat)

  {
  	return of_fdt_match(initial_boot_params, node, compat);
  }

  #ifdef CONFIG_BLK_DEV_INITRD
  /**
   * early_init_dt_check_for_initrd - Decode initrd location from flat tree
   * @node: reference to node containing initrd location ('chosen')
   */
  void __init early_init_dt_check_for_initrd(unsigned long node)
  {

  	unsigned long start, end, len;

  	__be32 *prop;

  
  	pr_debug("Looking for initrd properties... ");
  
  	prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);

  	if (!prop)
  		return;
  	start = of_read_ulong(prop, len/4);
  
  	prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
  	if (!prop)
  		return;
  	end = of_read_ulong(prop, len/4);

  	early_init_dt_setup_initrd_arch(start, end);
  	pr_debug("initrd_start=0x%lx  initrd_end=0x%lx
  ", start, end);

  }
  #else
  inline void early_init_dt_check_for_initrd(unsigned long node)
  {
  }
  #endif /* CONFIG_BLK_DEV_INITRD */

  /**

   * early_init_dt_scan_root - fetch the top level address and size cells
   */
  int __init early_init_dt_scan_root(unsigned long node, const char *uname,
  				   int depth, void *data)
  {

  	__be32 *prop;

  
  	if (depth != 0)
  		return 0;

  	dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
  	dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;

  	prop = of_get_flat_dt_prop(node, "#size-cells", NULL);

  	if (prop)
  		dt_root_size_cells = be32_to_cpup(prop);

  	pr_debug("dt_root_size_cells = %x
  ", dt_root_size_cells);
  
  	prop = of_get_flat_dt_prop(node, "#address-cells", NULL);

  	if (prop)
  		dt_root_addr_cells = be32_to_cpup(prop);

  	pr_debug("dt_root_addr_cells = %x
  ", dt_root_addr_cells);
  
  	/* break now */
  	return 1;
  }

  u64 __init dt_mem_next_cell(int s, __be32 **cellp)

  {

  	__be32 *p = *cellp;

  
  	*cellp = p + s;
  	return of_read_number(p, s);
  }

  /**
   * early_init_dt_scan_memory - Look for an parse memory nodes
   */
  int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
  				     int depth, void *data)
  {
  	char *type = of_get_flat_dt_prop(node, "device_type", NULL);
  	__be32 *reg, *endp;
  	unsigned long l;
  
  	/* We are scanning "memory" nodes only */
  	if (type == NULL) {
  		/*
  		 * The longtrail doesn't have a device_type on the
  		 * /memory node, so look for the node called /memory@0.
  		 */
  		if (depth != 1 || strcmp(uname, "memory@0") != 0)
  			return 0;
  	} else if (strcmp(type, "memory") != 0)
  		return 0;
  
  	reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
  	if (reg == NULL)
  		reg = of_get_flat_dt_prop(node, "reg", &l);
  	if (reg == NULL)
  		return 0;
  
  	endp = reg + (l / sizeof(__be32));
  
  	pr_debug("memory scan node %s, reg size %ld, data: %x %x %x %x,
  ",
  	    uname, l, reg[0], reg[1], reg[2], reg[3]);
  
  	while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
  		u64 base, size;
  
  		base = dt_mem_next_cell(dt_root_addr_cells, &reg);
  		size = dt_mem_next_cell(dt_root_size_cells, &reg);
  
  		if (size == 0)
  			continue;
  		pr_debug(" - %llx ,  %llx
  ", (unsigned long long)base,
  		    (unsigned long long)size);
  
  		early_init_dt_add_memory_arch(base, size);
  	}
  
  	return 0;
  }

  int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
  				     int depth, void *data)
  {
  	unsigned long l;
  	char *p;
  
  	pr_debug("search \"chosen\", depth: %d, uname: %s
  ", depth, uname);

  	if (depth != 1 || !data ||

  	    (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
  		return 0;
  
  	early_init_dt_check_for_initrd(node);

  	/* Retrieve command line */

  	p = of_get_flat_dt_prop(node, "bootargs", &l);
  	if (p != NULL && l > 0)

  		strlcpy(data, p, min((int)l, COMMAND_LINE_SIZE));

  	/*
  	 * CONFIG_CMDLINE is meant to be a default in case nothing else
  	 * managed to set the command line, unless CONFIG_CMDLINE_FORCE
  	 * is set in which case we override whatever was found earlier.
  	 */

  #ifdef CONFIG_CMDLINE
  #ifndef CONFIG_CMDLINE_FORCE

  	if (!((char *)data)[0])

  #endif

  		strlcpy(data, CONFIG_CMDLINE, COMMAND_LINE_SIZE);

  #endif /* CONFIG_CMDLINE */

  	pr_debug("Command line is: %s
  ", (char*)data);

  
  	/* break now */
  	return 1;
  }

  /**

   * unflatten_device_tree - create tree of device_nodes from flat blob
   *
   * unflattens the device-tree passed by the firmware, creating the
   * tree of struct device_node. It also fills the "name" and "type"
   * pointers of the nodes so the normal device-tree walking functions
   * can be used.
   */
  void __init unflatten_device_tree(void)
  {

  	__unflatten_device_tree(initial_boot_params, &allnodes,

  				early_init_dt_alloc_memory_arch);

  	/* Get pointer to "/chosen" and "/aliasas" nodes for use everywhere */
  	of_alias_scan(early_init_dt_alloc_memory_arch);

  }

  
  #endif /* CONFIG_OF_EARLY_FLATTREE */