/*
   * drivers/of/property.c - Procedures for accessing and interpreting
   *			   Devicetree properties and graphs.
   *
   * Initially created by copying procedures from drivers/of/base.c. This
   * file contains the OF property as well as the OF graph interface
   * functions.
   *
   * 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 and
   *  Grant Likely.
   *
   *      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.
   */
  
  #define pr_fmt(fmt)	"OF: " fmt
  
  #include <linux/of.h>
  #include <linux/of_device.h>
  #include <linux/of_graph.h>
  #include <linux/string.h>
  
  #include "of_private.h"
  
  /**
   * of_property_count_elems_of_size - Count the number of elements in a property
   *
   * @np:		device node from which the property value is to be read.
   * @propname:	name of the property to be searched.
   * @elem_size:	size of the individual element
   *
   * Search for a property in a device node and count the number of elements of
   * size elem_size in it. Returns number of elements on sucess, -EINVAL if the
   * property does not exist or its length does not match a multiple of elem_size
   * and -ENODATA if the property does not have a value.
   */
  int of_property_count_elems_of_size(const struct device_node *np,
  				const char *propname, int elem_size)
  {
  	struct property *prop = of_find_property(np, propname, NULL);
  
  	if (!prop)
  		return -EINVAL;
  	if (!prop->value)
  		return -ENODATA;
  
  	if (prop->length % elem_size != 0) {

  		pr_err("size of %s in node %pOF is not a multiple of %d
  ",
  		       propname, np, elem_size);

  		return -EINVAL;
  	}
  
  	return prop->length / elem_size;
  }
  EXPORT_SYMBOL_GPL(of_property_count_elems_of_size);
  
  /**
   * of_find_property_value_of_size
   *
   * @np:		device node from which the property value is to be read.
   * @propname:	name of the property to be searched.
   * @min:	minimum allowed length of property value
   * @max:	maximum allowed length of property value (0 means unlimited)
   * @len:	if !=NULL, actual length is written to here
   *
   * Search for a property in a device node and valid the requested size.
   * Returns the property value on success, -EINVAL if the property does not
   *  exist, -ENODATA if property does not have a value, and -EOVERFLOW if the
   * property data is too small or too large.
   *
   */
  static void *of_find_property_value_of_size(const struct device_node *np,
  			const char *propname, u32 min, u32 max, size_t *len)
  {
  	struct property *prop = of_find_property(np, propname, NULL);
  
  	if (!prop)
  		return ERR_PTR(-EINVAL);
  	if (!prop->value)
  		return ERR_PTR(-ENODATA);
  	if (prop->length < min)
  		return ERR_PTR(-EOVERFLOW);
  	if (max && prop->length > max)
  		return ERR_PTR(-EOVERFLOW);
  
  	if (len)
  		*len = prop->length;
  
  	return prop->value;
  }
  
  /**
   * of_property_read_u32_index - Find and read a u32 from a multi-value property.
   *
   * @np:		device node from which the property value is to be read.
   * @propname:	name of the property to be searched.
   * @index:	index of the u32 in the list of values
   * @out_value:	pointer to return value, modified only if no error.
   *
   * Search for a property in a device node and read nth 32-bit value from
   * it. Returns 0 on success, -EINVAL if the property does not exist,
   * -ENODATA if property does not have a value, and -EOVERFLOW if the
   * property data isn't large enough.
   *
   * The out_value is modified only if a valid u32 value can be decoded.
   */
  int of_property_read_u32_index(const struct device_node *np,
  				       const char *propname,
  				       u32 index, u32 *out_value)
  {
  	const u32 *val = of_find_property_value_of_size(np, propname,
  					((index + 1) * sizeof(*out_value)),
  					0,
  					NULL);
  
  	if (IS_ERR(val))
  		return PTR_ERR(val);
  
  	*out_value = be32_to_cpup(((__be32 *)val) + index);
  	return 0;
  }
  EXPORT_SYMBOL_GPL(of_property_read_u32_index);
  
  /**
   * of_property_read_u64_index - Find and read a u64 from a multi-value property.
   *
   * @np:		device node from which the property value is to be read.
   * @propname:	name of the property to be searched.
   * @index:	index of the u64 in the list of values
   * @out_value:	pointer to return value, modified only if no error.
   *
   * Search for a property in a device node and read nth 64-bit value from
   * it. Returns 0 on success, -EINVAL if the property does not exist,
   * -ENODATA if property does not have a value, and -EOVERFLOW if the
   * property data isn't large enough.
   *
   * The out_value is modified only if a valid u64 value can be decoded.
   */
  int of_property_read_u64_index(const struct device_node *np,
  				       const char *propname,
  				       u32 index, u64 *out_value)
  {
  	const u64 *val = of_find_property_value_of_size(np, propname,
  					((index + 1) * sizeof(*out_value)),
  					0, NULL);
  
  	if (IS_ERR(val))
  		return PTR_ERR(val);
  
  	*out_value = be64_to_cpup(((__be64 *)val) + index);
  	return 0;
  }
  EXPORT_SYMBOL_GPL(of_property_read_u64_index);
  
  /**
   * of_property_read_variable_u8_array - Find and read an array of u8 from a
   * property, with bounds on the minimum and maximum array size.
   *
   * @np:		device node from which the property value is to be read.
   * @propname:	name of the property to be searched.
   * @out_values:	pointer to return value, modified only if return value is 0.
   * @sz_min:	minimum number of array elements to read
   * @sz_max:	maximum number of array elements to read, if zero there is no
   *		upper limit on the number of elements in the dts entry but only
   *		sz_min will be read.
   *
   * Search for a property in a device node and read 8-bit value(s) from
   * it. Returns number of elements read on success, -EINVAL if the property
   * does not exist, -ENODATA if property does not have a value, and -EOVERFLOW
   * if the property data is smaller than sz_min or longer than sz_max.
   *
   * dts entry of array should be like:
   *	property = /bits/ 8 <0x50 0x60 0x70>;
   *
   * The out_values is modified only if a valid u8 value can be decoded.
   */
  int of_property_read_variable_u8_array(const struct device_node *np,
  					const char *propname, u8 *out_values,
  					size_t sz_min, size_t sz_max)
  {
  	size_t sz, count;
  	const u8 *val = of_find_property_value_of_size(np, propname,
  						(sz_min * sizeof(*out_values)),
  						(sz_max * sizeof(*out_values)),
  						&sz);
  
  	if (IS_ERR(val))
  		return PTR_ERR(val);
  
  	if (!sz_max)
  		sz = sz_min;
  	else
  		sz /= sizeof(*out_values);
  
  	count = sz;
  	while (count--)
  		*out_values++ = *val++;
  
  	return sz;
  }
  EXPORT_SYMBOL_GPL(of_property_read_variable_u8_array);
  
  /**
   * of_property_read_variable_u16_array - Find and read an array of u16 from a
   * property, with bounds on the minimum and maximum array size.
   *
   * @np:		device node from which the property value is to be read.
   * @propname:	name of the property to be searched.
   * @out_values:	pointer to return value, modified only if return value is 0.
   * @sz_min:	minimum number of array elements to read
   * @sz_max:	maximum number of array elements to read, if zero there is no
   *		upper limit on the number of elements in the dts entry but only
   *		sz_min will be read.
   *
   * Search for a property in a device node and read 16-bit value(s) from
   * it. Returns number of elements read on success, -EINVAL if the property
   * does not exist, -ENODATA if property does not have a value, and -EOVERFLOW
   * if the property data is smaller than sz_min or longer than sz_max.
   *
   * dts entry of array should be like:
   *	property = /bits/ 16 <0x5000 0x6000 0x7000>;
   *
   * The out_values is modified only if a valid u16 value can be decoded.
   */
  int of_property_read_variable_u16_array(const struct device_node *np,
  					const char *propname, u16 *out_values,
  					size_t sz_min, size_t sz_max)
  {
  	size_t sz, count;
  	const __be16 *val = of_find_property_value_of_size(np, propname,
  						(sz_min * sizeof(*out_values)),
  						(sz_max * sizeof(*out_values)),
  						&sz);
  
  	if (IS_ERR(val))
  		return PTR_ERR(val);
  
  	if (!sz_max)
  		sz = sz_min;
  	else
  		sz /= sizeof(*out_values);
  
  	count = sz;
  	while (count--)
  		*out_values++ = be16_to_cpup(val++);
  
  	return sz;
  }
  EXPORT_SYMBOL_GPL(of_property_read_variable_u16_array);
  
  /**
   * of_property_read_variable_u32_array - Find and read an array of 32 bit
   * integers from a property, with bounds on the minimum and maximum array size.
   *
   * @np:		device node from which the property value is to be read.
   * @propname:	name of the property to be searched.
   * @out_values:	pointer to return value, modified only if return value is 0.
   * @sz_min:	minimum number of array elements to read
   * @sz_max:	maximum number of array elements to read, if zero there is no
   *		upper limit on the number of elements in the dts entry but only
   *		sz_min will be read.
   *
   * Search for a property in a device node and read 32-bit value(s) from
   * it. Returns number of elements read on success, -EINVAL if the property
   * does not exist, -ENODATA if property does not have a value, and -EOVERFLOW
   * if the property data is smaller than sz_min or longer than sz_max.
   *
   * The out_values is modified only if a valid u32 value can be decoded.
   */
  int of_property_read_variable_u32_array(const struct device_node *np,
  			       const char *propname, u32 *out_values,
  			       size_t sz_min, size_t sz_max)
  {
  	size_t sz, count;
  	const __be32 *val = of_find_property_value_of_size(np, propname,
  						(sz_min * sizeof(*out_values)),
  						(sz_max * sizeof(*out_values)),
  						&sz);
  
  	if (IS_ERR(val))
  		return PTR_ERR(val);
  
  	if (!sz_max)
  		sz = sz_min;
  	else
  		sz /= sizeof(*out_values);
  
  	count = sz;
  	while (count--)
  		*out_values++ = be32_to_cpup(val++);
  
  	return sz;
  }
  EXPORT_SYMBOL_GPL(of_property_read_variable_u32_array);
  
  /**
   * of_property_read_u64 - Find and read a 64 bit integer from a property
   * @np:		device node from which the property value is to be read.
   * @propname:	name of the property to be searched.
   * @out_value:	pointer to return value, modified only if return value is 0.
   *
   * Search for a property in a device node and read a 64-bit value from
   * it. Returns 0 on success, -EINVAL if the property does not exist,
   * -ENODATA if property does not have a value, and -EOVERFLOW if the
   * property data isn't large enough.
   *
   * The out_value is modified only if a valid u64 value can be decoded.
   */
  int of_property_read_u64(const struct device_node *np, const char *propname,
  			 u64 *out_value)
  {
  	const __be32 *val = of_find_property_value_of_size(np, propname,
  						sizeof(*out_value),
  						0,
  						NULL);
  
  	if (IS_ERR(val))
  		return PTR_ERR(val);
  
  	*out_value = of_read_number(val, 2);
  	return 0;
  }
  EXPORT_SYMBOL_GPL(of_property_read_u64);
  
  /**
   * of_property_read_variable_u64_array - Find and read an array of 64 bit
   * integers from a property, with bounds on the minimum and maximum array size.
   *
   * @np:		device node from which the property value is to be read.
   * @propname:	name of the property to be searched.
   * @out_values:	pointer to return value, modified only if return value is 0.
   * @sz_min:	minimum number of array elements to read
   * @sz_max:	maximum number of array elements to read, if zero there is no
   *		upper limit on the number of elements in the dts entry but only
   *		sz_min will be read.
   *
   * Search for a property in a device node and read 64-bit value(s) from
   * it. Returns number of elements read on success, -EINVAL if the property
   * does not exist, -ENODATA if property does not have a value, and -EOVERFLOW
   * if the property data is smaller than sz_min or longer than sz_max.
   *
   * The out_values is modified only if a valid u64 value can be decoded.
   */
  int of_property_read_variable_u64_array(const struct device_node *np,
  			       const char *propname, u64 *out_values,
  			       size_t sz_min, size_t sz_max)
  {
  	size_t sz, count;
  	const __be32 *val = of_find_property_value_of_size(np, propname,
  						(sz_min * sizeof(*out_values)),
  						(sz_max * sizeof(*out_values)),
  						&sz);
  
  	if (IS_ERR(val))
  		return PTR_ERR(val);
  
  	if (!sz_max)
  		sz = sz_min;
  	else
  		sz /= sizeof(*out_values);
  
  	count = sz;
  	while (count--) {
  		*out_values++ = of_read_number(val, 2);
  		val += 2;
  	}
  
  	return sz;
  }
  EXPORT_SYMBOL_GPL(of_property_read_variable_u64_array);
  
  /**
   * of_property_read_string - Find and read a string from a property
   * @np:		device node from which the property value is to be read.
   * @propname:	name of the property to be searched.
   * @out_string:	pointer to null terminated return string, modified only if
   *		return value is 0.
   *
   * Search for a property in a device tree node and retrieve a null
   * terminated string value (pointer to data, not a copy). Returns 0 on
   * success, -EINVAL if the property does not exist, -ENODATA if property
   * does not have a value, and -EILSEQ if the string is not null-terminated
   * within the length of the property data.
   *
   * The out_string pointer is modified only if a valid string can be decoded.
   */
  int of_property_read_string(const struct device_node *np, const char *propname,
  				const char **out_string)
  {
  	const struct property *prop = of_find_property(np, propname, NULL);
  	if (!prop)
  		return -EINVAL;
  	if (!prop->value)
  		return -ENODATA;
  	if (strnlen(prop->value, prop->length) >= prop->length)
  		return -EILSEQ;
  	*out_string = prop->value;
  	return 0;
  }
  EXPORT_SYMBOL_GPL(of_property_read_string);
  
  /**
   * of_property_match_string() - Find string in a list and return index
   * @np: pointer to node containing string list property
   * @propname: string list property name
   * @string: pointer to string to search for in string list
   *
   * This function searches a string list property and returns the index
   * of a specific string value.
   */
  int of_property_match_string(const struct device_node *np, const char *propname,
  			     const char *string)
  {
  	const struct property *prop = of_find_property(np, propname, NULL);
  	size_t l;
  	int i;
  	const char *p, *end;
  
  	if (!prop)
  		return -EINVAL;
  	if (!prop->value)
  		return -ENODATA;
  
  	p = prop->value;
  	end = p + prop->length;
  
  	for (i = 0; p < end; i++, p += l) {
  		l = strnlen(p, end - p) + 1;
  		if (p + l > end)
  			return -EILSEQ;
  		pr_debug("comparing %s with %s
  ", string, p);
  		if (strcmp(string, p) == 0)
  			return i; /* Found it; return index */
  	}
  	return -ENODATA;
  }
  EXPORT_SYMBOL_GPL(of_property_match_string);
  
  /**
   * of_property_read_string_helper() - Utility helper for parsing string properties
   * @np:		device node from which the property value is to be read.
   * @propname:	name of the property to be searched.
   * @out_strs:	output array of string pointers.
   * @sz:		number of array elements to read.
   * @skip:	Number of strings to skip over at beginning of list.
   *
   * Don't call this function directly. It is a utility helper for the
   * of_property_read_string*() family of functions.
   */
  int of_property_read_string_helper(const struct device_node *np,
  				   const char *propname, const char **out_strs,
  				   size_t sz, int skip)
  {
  	const struct property *prop = of_find_property(np, propname, NULL);
  	int l = 0, i = 0;
  	const char *p, *end;
  
  	if (!prop)
  		return -EINVAL;
  	if (!prop->value)
  		return -ENODATA;
  	p = prop->value;
  	end = p + prop->length;
  
  	for (i = 0; p < end && (!out_strs || i < skip + sz); i++, p += l) {
  		l = strnlen(p, end - p) + 1;
  		if (p + l > end)
  			return -EILSEQ;
  		if (out_strs && i >= skip)
  			*out_strs++ = p;
  	}
  	i -= skip;
  	return i <= 0 ? -ENODATA : i;
  }
  EXPORT_SYMBOL_GPL(of_property_read_string_helper);
  
  const __be32 *of_prop_next_u32(struct property *prop, const __be32 *cur,
  			       u32 *pu)
  {
  	const void *curv = cur;
  
  	if (!prop)
  		return NULL;
  
  	if (!cur) {
  		curv = prop->value;
  		goto out_val;
  	}
  
  	curv += sizeof(*cur);
  	if (curv >= prop->value + prop->length)
  		return NULL;
  
  out_val:
  	*pu = be32_to_cpup(curv);
  	return curv;
  }
  EXPORT_SYMBOL_GPL(of_prop_next_u32);
  
  const char *of_prop_next_string(struct property *prop, const char *cur)
  {
  	const void *curv = cur;
  
  	if (!prop)
  		return NULL;
  
  	if (!cur)
  		return prop->value;
  
  	curv += strlen(cur) + 1;
  	if (curv >= prop->value + prop->length)
  		return NULL;
  
  	return curv;
  }
  EXPORT_SYMBOL_GPL(of_prop_next_string);
  
  /**
   * of_graph_parse_endpoint() - parse common endpoint node properties
   * @node: pointer to endpoint device_node
   * @endpoint: pointer to the OF endpoint data structure
   *
   * The caller should hold a reference to @node.
   */
  int of_graph_parse_endpoint(const struct device_node *node,
  			    struct of_endpoint *endpoint)
  {
  	struct device_node *port_node = of_get_parent(node);

  	WARN_ONCE(!port_node, "%s(): endpoint %pOF has no parent node
  ",
  		  __func__, node);

  
  	memset(endpoint, 0, sizeof(*endpoint));
  
  	endpoint->local_node = node;
  	/*
  	 * It doesn't matter whether the two calls below succeed.
  	 * If they don't then the default value 0 is used.
  	 */
  	of_property_read_u32(port_node, "reg", &endpoint->port);
  	of_property_read_u32(node, "reg", &endpoint->id);
  
  	of_node_put(port_node);
  
  	return 0;
  }
  EXPORT_SYMBOL(of_graph_parse_endpoint);
  
  /**
   * of_graph_get_port_by_id() - get the port matching a given id
   * @parent: pointer to the parent device node
   * @id: id of the port
   *
   * Return: A 'port' node pointer with refcount incremented. The caller
   * has to use of_node_put() on it when done.
   */
  struct device_node *of_graph_get_port_by_id(struct device_node *parent, u32 id)
  {
  	struct device_node *node, *port;
  
  	node = of_get_child_by_name(parent, "ports");
  	if (node)
  		parent = node;
  
  	for_each_child_of_node(parent, port) {
  		u32 port_id = 0;
  
  		if (of_node_cmp(port->name, "port") != 0)
  			continue;
  		of_property_read_u32(port, "reg", &port_id);
  		if (id == port_id)
  			break;
  	}
  
  	of_node_put(node);
  
  	return port;
  }
  EXPORT_SYMBOL(of_graph_get_port_by_id);
  
  /**
   * of_graph_get_next_endpoint() - get next endpoint node
   * @parent: pointer to the parent device node
   * @prev: previous endpoint node, or NULL to get first
   *
   * Return: An 'endpoint' node pointer with refcount incremented. Refcount
   * of the passed @prev node is decremented.
   */
  struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
  					struct device_node *prev)
  {
  	struct device_node *endpoint;
  	struct device_node *port;
  
  	if (!parent)
  		return NULL;
  
  	/*
  	 * Start by locating the port node. If no previous endpoint is specified
  	 * search for the first port node, otherwise get the previous endpoint
  	 * parent port node.
  	 */
  	if (!prev) {
  		struct device_node *node;
  
  		node = of_get_child_by_name(parent, "ports");
  		if (node)
  			parent = node;
  
  		port = of_get_child_by_name(parent, "port");
  		of_node_put(node);
  
  		if (!port) {

  			pr_err("graph: no port node found in %pOF
  ", parent);

  			return NULL;
  		}
  	} else {
  		port = of_get_parent(prev);

  		if (WARN_ONCE(!port, "%s(): endpoint %pOF has no parent node
  ",
  			      __func__, prev))

  			return NULL;
  	}
  
  	while (1) {
  		/*
  		 * Now that we have a port node, get the next endpoint by
  		 * getting the next child. If the previous endpoint is NULL this
  		 * will return the first child.
  		 */
  		endpoint = of_get_next_child(port, prev);
  		if (endpoint) {
  			of_node_put(port);
  			return endpoint;
  		}
  
  		/* No more endpoints under this port, try the next one. */
  		prev = NULL;
  
  		do {
  			port = of_get_next_child(parent, port);
  			if (!port)
  				return NULL;
  		} while (of_node_cmp(port->name, "port"));
  	}
  }
  EXPORT_SYMBOL(of_graph_get_next_endpoint);
  
  /**
   * of_graph_get_endpoint_by_regs() - get endpoint node of specific identifiers
   * @parent: pointer to the parent device node
   * @port_reg: identifier (value of reg property) of the parent port node
   * @reg: identifier (value of reg property) of the endpoint node
   *
   * Return: An 'endpoint' node pointer which is identified by reg and at the same
   * is the child of a port node identified by port_reg. reg and port_reg are
   * ignored when they are -1.
   */
  struct device_node *of_graph_get_endpoint_by_regs(
  	const struct device_node *parent, int port_reg, int reg)
  {
  	struct of_endpoint endpoint;
  	struct device_node *node = NULL;
  
  	for_each_endpoint_of_node(parent, node) {
  		of_graph_parse_endpoint(node, &endpoint);
  		if (((port_reg == -1) || (endpoint.port == port_reg)) &&
  			((reg == -1) || (endpoint.id == reg)))
  			return node;
  	}
  
  	return NULL;
  }
  EXPORT_SYMBOL(of_graph_get_endpoint_by_regs);
  
  /**

   * of_graph_get_remote_endpoint() - get remote endpoint node
   * @node: pointer to a local endpoint device_node
   *
   * Return: Remote endpoint node associated with remote endpoint node linked
   *	   to @node. Use of_node_put() on it when done.
   */
  struct device_node *of_graph_get_remote_endpoint(const struct device_node *node)
  {
  	/* Get remote endpoint node. */
  	return of_parse_phandle(node, "remote-endpoint", 0);
  }
  EXPORT_SYMBOL(of_graph_get_remote_endpoint);
  
  /**
   * of_graph_get_port_parent() - get port's parent node
   * @node: pointer to a local endpoint device_node
   *
   * Return: device node associated with endpoint node linked
   *	   to @node. Use of_node_put() on it when done.
   */
  struct device_node *of_graph_get_port_parent(struct device_node *node)
  {
  	unsigned int depth;

  	if (!node)
  		return NULL;
  
  	/*
  	 * Preserve usecount for passed in node as of_get_next_parent()
  	 * will do of_node_put() on it.
  	 */
  	of_node_get(node);

  	/* Walk 3 levels up only if there is 'ports' node. */
  	for (depth = 3; depth && node; depth--) {
  		node = of_get_next_parent(node);
  		if (depth == 2 && of_node_cmp(node->name, "ports"))
  			break;
  	}
  	return node;
  }
  EXPORT_SYMBOL(of_graph_get_port_parent);
  
  /**

   * of_graph_get_remote_port_parent() - get remote port's parent node
   * @node: pointer to a local endpoint device_node
   *
   * Return: Remote device node associated with remote endpoint node linked
   *	   to @node. Use of_node_put() on it when done.
   */
  struct device_node *of_graph_get_remote_port_parent(
  			       const struct device_node *node)
  {

  	struct device_node *np, *pp;

  
  	/* Get remote endpoint node. */

  	np = of_graph_get_remote_endpoint(node);

  	pp = of_graph_get_port_parent(np);
  
  	of_node_put(np);
  
  	return pp;

  }
  EXPORT_SYMBOL(of_graph_get_remote_port_parent);
  
  /**
   * of_graph_get_remote_port() - get remote port node
   * @node: pointer to a local endpoint device_node
   *
   * Return: Remote port node associated with remote endpoint node linked
   *	   to @node. Use of_node_put() on it when done.
   */
  struct device_node *of_graph_get_remote_port(const struct device_node *node)
  {
  	struct device_node *np;
  
  	/* Get remote endpoint node. */

  	np = of_graph_get_remote_endpoint(node);

  	if (!np)
  		return NULL;
  	return of_get_next_parent(np);
  }
  EXPORT_SYMBOL(of_graph_get_remote_port);

  int of_graph_get_endpoint_count(const struct device_node *np)
  {
  	struct device_node *endpoint;
  	int num = 0;
  
  	for_each_endpoint_of_node(np, endpoint)
  		num++;
  
  	return num;
  }
  EXPORT_SYMBOL(of_graph_get_endpoint_count);

  /**
   * of_graph_get_remote_node() - get remote parent device_node for given port/endpoint
   * @node: pointer to parent device_node containing graph port/endpoint
   * @port: identifier (value of reg property) of the parent port node
   * @endpoint: identifier (value of reg property) of the endpoint node
   *
   * Return: Remote device node associated with remote endpoint node linked
   *	   to @node. Use of_node_put() on it when done.
   */
  struct device_node *of_graph_get_remote_node(const struct device_node *node,
  					     u32 port, u32 endpoint)
  {
  	struct device_node *endpoint_node, *remote;
  
  	endpoint_node = of_graph_get_endpoint_by_regs(node, port, endpoint);
  	if (!endpoint_node) {

  		pr_debug("no valid endpoint (%d, %d) for node %pOF
  ",
  			 port, endpoint, node);

  		return NULL;
  	}
  
  	remote = of_graph_get_remote_port_parent(endpoint_node);
  	of_node_put(endpoint_node);
  	if (!remote) {
  		pr_debug("no valid remote node
  ");
  		return NULL;
  	}
  
  	if (!of_device_is_available(remote)) {
  		pr_debug("not available for remote node
  ");

  		of_node_put(remote);

  		return NULL;
  	}
  
  	return remote;
  }
  EXPORT_SYMBOL(of_graph_get_remote_node);

  
  static void of_fwnode_get(struct fwnode_handle *fwnode)
  {
  	of_node_get(to_of_node(fwnode));
  }
  
  static void of_fwnode_put(struct fwnode_handle *fwnode)
  {
  	of_node_put(to_of_node(fwnode));
  }

  static bool of_fwnode_device_is_available(const struct fwnode_handle *fwnode)

  {
  	return of_device_is_available(to_of_node(fwnode));
  }

  static bool of_fwnode_property_present(const struct fwnode_handle *fwnode,

  				       const char *propname)
  {
  	return of_property_read_bool(to_of_node(fwnode), propname);
  }

  static int of_fwnode_property_read_int_array(const struct fwnode_handle *fwnode,

  					     const char *propname,
  					     unsigned int elem_size, void *val,
  					     size_t nval)
  {

  	const struct device_node *node = to_of_node(fwnode);

  
  	if (!val)
  		return of_property_count_elems_of_size(node, propname,
  						       elem_size);
  
  	switch (elem_size) {
  	case sizeof(u8):
  		return of_property_read_u8_array(node, propname, val, nval);
  	case sizeof(u16):
  		return of_property_read_u16_array(node, propname, val, nval);
  	case sizeof(u32):
  		return of_property_read_u32_array(node, propname, val, nval);
  	case sizeof(u64):
  		return of_property_read_u64_array(node, propname, val, nval);
  	}
  
  	return -ENXIO;
  }

  static int
  of_fwnode_property_read_string_array(const struct fwnode_handle *fwnode,
  				     const char *propname, const char **val,
  				     size_t nval)

  {

  	const struct device_node *node = to_of_node(fwnode);

  
  	return val ?
  		of_property_read_string_array(node, propname, val, nval) :
  		of_property_count_strings(node, propname);
  }

  static struct fwnode_handle *
  of_fwnode_get_parent(const struct fwnode_handle *fwnode)

  {
  	return of_fwnode_handle(of_get_parent(to_of_node(fwnode)));
  }
  
  static struct fwnode_handle *

  of_fwnode_get_next_child_node(const struct fwnode_handle *fwnode,

  			      struct fwnode_handle *child)
  {
  	return of_fwnode_handle(of_get_next_available_child(to_of_node(fwnode),
  							    to_of_node(child)));
  }
  
  static struct fwnode_handle *

  of_fwnode_get_named_child_node(const struct fwnode_handle *fwnode,

  			       const char *childname)
  {

  	const struct device_node *node = to_of_node(fwnode);

  	struct device_node *child;
  
  	for_each_available_child_of_node(node, child)
  		if (!of_node_cmp(child->name, childname))
  			return of_fwnode_handle(child);
  
  	return NULL;
  }

  static int
  of_fwnode_get_reference_args(const struct fwnode_handle *fwnode,
  			     const char *prop, const char *nargs_prop,
  			     unsigned int nargs, unsigned int index,
  			     struct fwnode_reference_args *args)
  {
  	struct of_phandle_args of_args;
  	unsigned int i;
  	int ret;
  
  	if (nargs_prop)
  		ret = of_parse_phandle_with_args(to_of_node(fwnode), prop,
  						 nargs_prop, index, &of_args);
  	else
  		ret = of_parse_phandle_with_fixed_args(to_of_node(fwnode), prop,
  						       nargs, index, &of_args);
  	if (ret < 0)
  		return ret;
  	if (!args)
  		return 0;
  
  	args->nargs = of_args.args_count;
  	args->fwnode = of_fwnode_handle(of_args.np);
  
  	for (i = 0; i < NR_FWNODE_REFERENCE_ARGS; i++)
  		args->args[i] = i < of_args.args_count ? of_args.args[i] : 0;
  
  	return 0;
  }

  static struct fwnode_handle *

  of_fwnode_graph_get_next_endpoint(const struct fwnode_handle *fwnode,

  				  struct fwnode_handle *prev)
  {
  	return of_fwnode_handle(of_graph_get_next_endpoint(to_of_node(fwnode),
  							   to_of_node(prev)));
  }
  
  static struct fwnode_handle *

  of_fwnode_graph_get_remote_endpoint(const struct fwnode_handle *fwnode)

  {

  	return of_fwnode_handle(
  		of_graph_get_remote_endpoint(to_of_node(fwnode)));

  }
  
  static struct fwnode_handle *
  of_fwnode_graph_get_port_parent(struct fwnode_handle *fwnode)
  {
  	struct device_node *np;
  
  	/* Get the parent of the port */

  	np = of_get_parent(to_of_node(fwnode));

  	if (!np)
  		return NULL;
  
  	/* Is this the "ports" node? If not, it's the port parent. */
  	if (of_node_cmp(np->name, "ports"))
  		return of_fwnode_handle(np);
  
  	return of_fwnode_handle(of_get_next_parent(np));
  }

  static int of_fwnode_graph_parse_endpoint(const struct fwnode_handle *fwnode,

  					  struct fwnode_endpoint *endpoint)
  {

  	const struct device_node *node = to_of_node(fwnode);

  	struct device_node *port_node = of_get_parent(node);
  
  	endpoint->local_fwnode = fwnode;
  
  	of_property_read_u32(port_node, "reg", &endpoint->port);
  	of_property_read_u32(node, "reg", &endpoint->id);
  
  	of_node_put(port_node);
  
  	return 0;
  }

  const struct fwnode_operations of_fwnode_ops = {
  	.get = of_fwnode_get,
  	.put = of_fwnode_put,

  	.device_is_available = of_fwnode_device_is_available,

  	.property_present = of_fwnode_property_present,
  	.property_read_int_array = of_fwnode_property_read_int_array,
  	.property_read_string_array = of_fwnode_property_read_string_array,
  	.get_parent = of_fwnode_get_parent,
  	.get_next_child_node = of_fwnode_get_next_child_node,
  	.get_named_child_node = of_fwnode_get_named_child_node,

  	.get_reference_args = of_fwnode_get_reference_args,

  	.graph_get_next_endpoint = of_fwnode_graph_get_next_endpoint,
  	.graph_get_remote_endpoint = of_fwnode_graph_get_remote_endpoint,
  	.graph_get_port_parent = of_fwnode_graph_get_port_parent,
  	.graph_parse_endpoint = of_fwnode_graph_parse_endpoint,

  };

  EXPORT_SYMBOL_GPL(of_fwnode_ops);