/*
   * Procedures for creating, accessing and interpreting the device tree.
   *
   * Paul Mackerras	August 1996.
   * Copyright (C) 1996-2005 Paul Mackerras.
   *
   *  Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
   *    {engebret|bergner}@us.ibm.com
   *
   *  Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
   *
   *  Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell.
   *
   *      This program is free software; you can redistribute it and/or
   *      modify it under the terms of the GNU General Public License
   *      as published by the Free Software Foundation; either version
   *      2 of the License, or (at your option) any later version.
   */
  #include <linux/module.h>
  #include <linux/of.h>

  #include <linux/spinlock.h>

  struct device_node *allnodes;

  /* use when traversing tree through the allnext, child, sibling,
   * or parent members of struct device_node.
   */
  DEFINE_RWLOCK(devtree_lock);

  
  int of_n_addr_cells(struct device_node *np)
  {
  	const int *ip;
  
  	do {
  		if (np->parent)
  			np = np->parent;
  		ip = of_get_property(np, "#address-cells", NULL);
  		if (ip)
  			return *ip;
  	} while (np->parent);
  	/* No #address-cells property for the root node */
  	return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
  }
  EXPORT_SYMBOL(of_n_addr_cells);
  
  int of_n_size_cells(struct device_node *np)
  {
  	const int *ip;
  
  	do {
  		if (np->parent)
  			np = np->parent;
  		ip = of_get_property(np, "#size-cells", NULL);
  		if (ip)
  			return *ip;
  	} while (np->parent);
  	/* No #size-cells property for the root node */
  	return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
  }
  EXPORT_SYMBOL(of_n_size_cells);

  struct property *of_find_property(const struct device_node *np,
  				  const char *name,
  				  int *lenp)
  {
  	struct property *pp;

  	if (!np)
  		return NULL;

  	read_lock(&devtree_lock);
  	for (pp = np->properties; pp != 0; pp = pp->next) {
  		if (of_prop_cmp(pp->name, name) == 0) {
  			if (lenp != 0)
  				*lenp = pp->length;
  			break;
  		}
  	}
  	read_unlock(&devtree_lock);
  
  	return pp;
  }
  EXPORT_SYMBOL(of_find_property);

  /*
   * Find a property with a given name for a given node
   * and return the value.
   */
  const void *of_get_property(const struct device_node *np, const char *name,
  			 int *lenp)
  {
  	struct property *pp = of_find_property(np, name, lenp);
  
  	return pp ? pp->value : NULL;
  }
  EXPORT_SYMBOL(of_get_property);

  
  /** Checks if the given "compat" string matches one of the strings in
   * the device's "compatible" property
   */
  int of_device_is_compatible(const struct device_node *device,
  		const char *compat)
  {
  	const char* cp;
  	int cplen, l;
  
  	cp = of_get_property(device, "compatible", &cplen);
  	if (cp == NULL)
  		return 0;
  	while (cplen > 0) {
  		if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
  			return 1;
  		l = strlen(cp) + 1;
  		cp += l;
  		cplen -= l;
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL(of_device_is_compatible);

  
  /**

   *  of_device_is_available - check if a device is available for use
   *
   *  @device: Node to check for availability
   *
   *  Returns 1 if the status property is absent or set to "okay" or "ok",
   *  0 otherwise
   */
  int of_device_is_available(const struct device_node *device)
  {
  	const char *status;
  	int statlen;
  
  	status = of_get_property(device, "status", &statlen);
  	if (status == NULL)
  		return 1;
  
  	if (statlen > 0) {
  		if (!strcmp(status, "okay") || !strcmp(status, "ok"))
  			return 1;
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL(of_device_is_available);
  
  /**

   *	of_get_parent - Get a node's parent if any
   *	@node:	Node to get parent
   *
   *	Returns a node pointer with refcount incremented, use
   *	of_node_put() on it when done.
   */
  struct device_node *of_get_parent(const struct device_node *node)
  {
  	struct device_node *np;
  
  	if (!node)
  		return NULL;
  
  	read_lock(&devtree_lock);
  	np = of_node_get(node->parent);
  	read_unlock(&devtree_lock);
  	return np;
  }
  EXPORT_SYMBOL(of_get_parent);

  
  /**

   *	of_get_next_parent - Iterate to a node's parent
   *	@node:	Node to get parent of
   *
   * 	This is like of_get_parent() except that it drops the
   * 	refcount on the passed node, making it suitable for iterating
   * 	through a node's parents.
   *
   *	Returns a node pointer with refcount incremented, use
   *	of_node_put() on it when done.
   */
  struct device_node *of_get_next_parent(struct device_node *node)
  {
  	struct device_node *parent;
  
  	if (!node)
  		return NULL;
  
  	read_lock(&devtree_lock);
  	parent = of_node_get(node->parent);
  	of_node_put(node);
  	read_unlock(&devtree_lock);
  	return parent;
  }
  
  /**

   *	of_get_next_child - Iterate a node childs
   *	@node:	parent node
   *	@prev:	previous child of the parent node, or NULL to get first
   *
   *	Returns a node pointer with refcount incremented, use
   *	of_node_put() on it when done.
   */
  struct device_node *of_get_next_child(const struct device_node *node,
  	struct device_node *prev)
  {
  	struct device_node *next;
  
  	read_lock(&devtree_lock);
  	next = prev ? prev->sibling : node->child;
  	for (; next; next = next->sibling)
  		if (of_node_get(next))
  			break;
  	of_node_put(prev);
  	read_unlock(&devtree_lock);
  	return next;
  }
  EXPORT_SYMBOL(of_get_next_child);

  
  /**
   *	of_find_node_by_path - Find a node matching a full OF path
   *	@path:	The full path to match
   *
   *	Returns a node pointer with refcount incremented, use
   *	of_node_put() on it when done.
   */
  struct device_node *of_find_node_by_path(const char *path)
  {
  	struct device_node *np = allnodes;
  
  	read_lock(&devtree_lock);
  	for (; np; np = np->allnext) {
  		if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
  		    && of_node_get(np))
  			break;
  	}
  	read_unlock(&devtree_lock);
  	return np;
  }
  EXPORT_SYMBOL(of_find_node_by_path);
  
  /**
   *	of_find_node_by_name - Find a node by its "name" property
   *	@from:	The node to start searching from or NULL, the node
   *		you pass will not be searched, only the next one
   *		will; typically, you pass what the previous call
   *		returned. of_node_put() will be called on it
   *	@name:	The name string to match against
   *
   *	Returns a node pointer with refcount incremented, use
   *	of_node_put() on it when done.
   */
  struct device_node *of_find_node_by_name(struct device_node *from,
  	const char *name)
  {
  	struct device_node *np;
  
  	read_lock(&devtree_lock);
  	np = from ? from->allnext : allnodes;
  	for (; np; np = np->allnext)
  		if (np->name && (of_node_cmp(np->name, name) == 0)
  		    && of_node_get(np))
  			break;
  	of_node_put(from);
  	read_unlock(&devtree_lock);
  	return np;
  }
  EXPORT_SYMBOL(of_find_node_by_name);
  
  /**
   *	of_find_node_by_type - Find a node by its "device_type" property
   *	@from:	The node to start searching from, or NULL to start searching
   *		the entire device tree. The node you pass will not be
   *		searched, only the next one will; typically, you pass
   *		what the previous call returned. of_node_put() will be
   *		called on from for you.
   *	@type:	The type string to match against
   *
   *	Returns a node pointer with refcount incremented, use
   *	of_node_put() on it when done.
   */
  struct device_node *of_find_node_by_type(struct device_node *from,
  	const char *type)
  {
  	struct device_node *np;
  
  	read_lock(&devtree_lock);
  	np = from ? from->allnext : allnodes;
  	for (; np; np = np->allnext)
  		if (np->type && (of_node_cmp(np->type, type) == 0)
  		    && of_node_get(np))
  			break;
  	of_node_put(from);
  	read_unlock(&devtree_lock);
  	return np;
  }
  EXPORT_SYMBOL(of_find_node_by_type);
  
  /**
   *	of_find_compatible_node - Find a node based on type and one of the
   *                                tokens in its "compatible" property
   *	@from:		The node to start searching from or NULL, the node
   *			you pass will not be searched, only the next one
   *			will; typically, you pass what the previous call
   *			returned. of_node_put() will be called on it
   *	@type:		The type string to match "device_type" or NULL to ignore
   *	@compatible:	The string to match to one of the tokens in the device
   *			"compatible" list.
   *
   *	Returns a node pointer with refcount incremented, use
   *	of_node_put() on it when done.
   */
  struct device_node *of_find_compatible_node(struct device_node *from,
  	const char *type, const char *compatible)
  {
  	struct device_node *np;
  
  	read_lock(&devtree_lock);
  	np = from ? from->allnext : allnodes;
  	for (; np; np = np->allnext) {
  		if (type
  		    && !(np->type && (of_node_cmp(np->type, type) == 0)))
  			continue;
  		if (of_device_is_compatible(np, compatible) && of_node_get(np))
  			break;
  	}
  	of_node_put(from);
  	read_unlock(&devtree_lock);
  	return np;
  }
  EXPORT_SYMBOL(of_find_compatible_node);

  
  /**

   *	of_find_node_with_property - Find a node which has a property with
   *                                   the given name.
   *	@from:		The node to start searching from or NULL, the node
   *			you pass will not be searched, only the next one
   *			will; typically, you pass what the previous call
   *			returned. of_node_put() will be called on it
   *	@prop_name:	The name of the property to look for.
   *
   *	Returns a node pointer with refcount incremented, use
   *	of_node_put() on it when done.
   */
  struct device_node *of_find_node_with_property(struct device_node *from,
  	const char *prop_name)
  {
  	struct device_node *np;
  	struct property *pp;
  
  	read_lock(&devtree_lock);
  	np = from ? from->allnext : allnodes;
  	for (; np; np = np->allnext) {
  		for (pp = np->properties; pp != 0; pp = pp->next) {
  			if (of_prop_cmp(pp->name, prop_name) == 0) {
  				of_node_get(np);
  				goto out;
  			}
  		}
  	}
  out:
  	of_node_put(from);
  	read_unlock(&devtree_lock);
  	return np;
  }
  EXPORT_SYMBOL(of_find_node_with_property);
  
  /**

   * of_match_node - Tell if an device_node has a matching of_match structure
   *	@matches:	array of of device match structures to search in
   *	@node:		the of device structure to match against
   *
   *	Low level utility function used by device matching.
   */
  const struct of_device_id *of_match_node(const struct of_device_id *matches,
  					 const struct device_node *node)
  {
  	while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
  		int match = 1;
  		if (matches->name[0])
  			match &= node->name
  				&& !strcmp(matches->name, node->name);
  		if (matches->type[0])
  			match &= node->type
  				&& !strcmp(matches->type, node->type);
  		if (matches->compatible[0])
  			match &= of_device_is_compatible(node,
  						matches->compatible);
  		if (match)
  			return matches;
  		matches++;
  	}
  	return NULL;
  }
  EXPORT_SYMBOL(of_match_node);
  
  /**
   *	of_find_matching_node - Find a node based on an of_device_id match
   *				table.
   *	@from:		The node to start searching from or NULL, the node
   *			you pass will not be searched, only the next one
   *			will; typically, you pass what the previous call
   *			returned. of_node_put() will be called on it
   *	@matches:	array of of device match structures to search in
   *
   *	Returns a node pointer with refcount incremented, use
   *	of_node_put() on it when done.
   */
  struct device_node *of_find_matching_node(struct device_node *from,
  					  const struct of_device_id *matches)
  {
  	struct device_node *np;
  
  	read_lock(&devtree_lock);
  	np = from ? from->allnext : allnodes;
  	for (; np; np = np->allnext) {
  		if (of_match_node(matches, np) && of_node_get(np))
  			break;
  	}
  	of_node_put(from);
  	read_unlock(&devtree_lock);
  	return np;
  }
  EXPORT_SYMBOL(of_find_matching_node);

  
  /**
   * of_modalias_table: Table of explicit compatible ==> modalias mappings
   *
   * This table allows particulare compatible property values to be mapped
   * to modalias strings.  This is useful for busses which do not directly
   * understand the OF device tree but are populated based on data contained
   * within the device tree.  SPI and I2C are the two current users of this
   * table.
   *
   * In most cases, devices do not need to be listed in this table because
   * the modalias value can be derived directly from the compatible table.
   * However, if for any reason a value cannot be derived, then this table
   * provides a method to override the implicit derivation.
   *
   * At the moment, a single table is used for all bus types because it is
   * assumed that the data size is small and that the compatible values
   * should already be distinct enough to differentiate between SPI, I2C
   * and other devices.
   */
  struct of_modalias_table {
  	char *of_device;
  	char *modalias;
  };
  static struct of_modalias_table of_modalias_table[] = {

  	{ "fsl,mcu-mpc8349emitx", "mcu-mpc8349emitx" },

  	{ "mmc-spi-slot", "mmc_spi" },

  };
  
  /**
   * of_modalias_node - Lookup appropriate modalias for a device node
   * @node:	pointer to a device tree node
   * @modalias:	Pointer to buffer that modalias value will be copied into
   * @len:	Length of modalias value
   *
   * Based on the value of the compatible property, this routine will determine

   * an appropriate modalias value for a particular device tree node.  Two
   * separate methods are attempted to derive a modalias value.

   *
   * First method is to lookup the compatible value in of_modalias_table.

   * Second is to strip off the manufacturer prefix from the first
   * compatible entry and use the remainder as modalias

   *
   * This routine returns 0 on success
   */
  int of_modalias_node(struct device_node *node, char *modalias, int len)
  {
  	int i, cplen;
  	const char *compatible;
  	const char *p;
  
  	/* 1. search for exception list entry */
  	for (i = 0; i < ARRAY_SIZE(of_modalias_table); i++) {
  		compatible = of_modalias_table[i].of_device;
  		if (!of_device_is_compatible(node, compatible))
  			continue;
  		strlcpy(modalias, of_modalias_table[i].modalias, len);
  		return 0;
  	}
  
  	compatible = of_get_property(node, "compatible", &cplen);
  	if (!compatible)
  		return -ENODEV;

  	/* 2. take first compatible entry and strip manufacturer */

  	p = strchr(compatible, ',');
  	if (!p)
  		return -ENODEV;
  	p++;
  	strlcpy(modalias, p, len);
  	return 0;
  }
  EXPORT_SYMBOL_GPL(of_modalias_node);

  /**

   * of_parse_phandle - Resolve a phandle property to a device_node pointer
   * @np: Pointer to device node holding phandle property
   * @phandle_name: Name of property holding a phandle value
   * @index: For properties holding a table of phandles, this is the index into
   *         the table
   *
   * Returns the device_node pointer with refcount incremented.  Use
   * of_node_put() on it when done.
   */
  struct device_node *
  of_parse_phandle(struct device_node *np, const char *phandle_name, int index)
  {
  	const phandle *phandle;
  	int size;
  
  	phandle = of_get_property(np, phandle_name, &size);
  	if ((!phandle) || (size < sizeof(*phandle) * (index + 1)))
  		return NULL;
  
  	return of_find_node_by_phandle(phandle[index]);
  }
  EXPORT_SYMBOL(of_parse_phandle);
  
  /**

   * of_parse_phandles_with_args - Find a node pointed by phandle in a list
   * @np:		pointer to a device tree node containing a list
   * @list_name:	property name that contains a list
   * @cells_name:	property name that specifies phandles' arguments count
   * @index:	index of a phandle to parse out

   * @out_node:	optional pointer to device_node struct pointer (will be filled)
   * @out_args:	optional pointer to arguments pointer (will be filled)

   *
   * This function is useful to parse lists of phandles and their arguments.
   * Returns 0 on success and fills out_node and out_args, on error returns
   * appropriate errno value.
   *
   * Example:
   *
   * phandle1: node1 {
   * 	#list-cells = <2>;
   * }
   *
   * phandle2: node2 {
   * 	#list-cells = <1>;
   * }
   *
   * node3 {
   * 	list = <&phandle1 1 2 &phandle2 3>;
   * }
   *
   * To get a device_node of the `node2' node you may call this:
   * of_parse_phandles_with_args(node3, "list", "#list-cells", 2, &node2, &args);
   */
  int of_parse_phandles_with_args(struct device_node *np, const char *list_name,
  				const char *cells_name, int index,
  				struct device_node **out_node,
  				const void **out_args)
  {
  	int ret = -EINVAL;
  	const u32 *list;
  	const u32 *list_end;
  	int size;
  	int cur_index = 0;
  	struct device_node *node = NULL;

  	const void *args = NULL;

  
  	list = of_get_property(np, list_name, &size);
  	if (!list) {
  		ret = -ENOENT;
  		goto err0;
  	}
  	list_end = list + size / sizeof(*list);
  
  	while (list < list_end) {
  		const u32 *cells;
  		const phandle *phandle;

  		phandle = list++;
  		args = list;

  
  		/* one cell hole in the list = <>; */

  		if (!*phandle)

  			goto next;

  
  		node = of_find_node_by_phandle(*phandle);
  		if (!node) {
  			pr_debug("%s: could not find phandle
  ",
  				 np->full_name);
  			goto err0;
  		}
  
  		cells = of_get_property(node, cells_name, &size);
  		if (!cells || size != sizeof(*cells)) {
  			pr_debug("%s: could not get %s for %s
  ",
  				 np->full_name, cells_name, node->full_name);
  			goto err1;
  		}

  		list += *cells;

  		if (list > list_end) {
  			pr_debug("%s: insufficient arguments length
  ",
  				 np->full_name);
  			goto err1;
  		}
  next:
  		if (cur_index == index)
  			break;
  
  		of_node_put(node);
  		node = NULL;

  		args = NULL;

  		cur_index++;
  	}
  
  	if (!node) {

  		/*
  		 * args w/o node indicates that the loop above has stopped at
  		 * the 'hole' cell. Report this differently.
  		 */
  		if (args)
  			ret = -EEXIST;
  		else
  			ret = -ENOENT;

  		goto err0;
  	}

  	if (out_node)
  		*out_node = node;
  	if (out_args)
  		*out_args = args;

  
  	return 0;
  err1:
  	of_node_put(node);
  err0:
  	pr_debug("%s failed with status %d
  ", __func__, ret);
  	return ret;
  }
  EXPORT_SYMBOL(of_parse_phandles_with_args);