/*
   * OF helpers for network devices.
   *
   * This file is released under the GPLv2
   *
   * Initially copied out of arch/powerpc/kernel/prom_parse.c
   */
  #include <linux/etherdevice.h>
  #include <linux/kernel.h>
  #include <linux/of_net.h>
  #include <linux/phy.h>
  #include <linux/export.h>
  
  /**
   * It maps 'enum phy_interface_t' found in include/linux/phy.h
   * into the device tree binding of 'phy-mode', so that Ethernet
   * device driver can get phy interface from device tree.
   */
  static const char *phy_modes[] = {
  	[PHY_INTERFACE_MODE_NA]		= "",
  	[PHY_INTERFACE_MODE_MII]	= "mii",
  	[PHY_INTERFACE_MODE_GMII]	= "gmii",
  	[PHY_INTERFACE_MODE_SGMII]	= "sgmii",
  	[PHY_INTERFACE_MODE_TBI]	= "tbi",
  	[PHY_INTERFACE_MODE_REVMII]	= "rev-mii",
  	[PHY_INTERFACE_MODE_RMII]	= "rmii",
  	[PHY_INTERFACE_MODE_RGMII]	= "rgmii",
  	[PHY_INTERFACE_MODE_RGMII_ID]	= "rgmii-id",
  	[PHY_INTERFACE_MODE_RGMII_RXID]	= "rgmii-rxid",
  	[PHY_INTERFACE_MODE_RGMII_TXID] = "rgmii-txid",
  	[PHY_INTERFACE_MODE_RTBI]	= "rtbi",
  	[PHY_INTERFACE_MODE_SMII]	= "smii",
  	[PHY_INTERFACE_MODE_XGMII]	= "xgmii",
  };
  
  /**
   * of_get_phy_mode - Get phy mode for given device_node
   * @np:	Pointer to the given device_node
   *
   * The function gets phy interface string from property 'phy-mode',
   * and return its index in phy_modes table, or errno in error case.
   */
  int of_get_phy_mode(struct device_node *np)
  {
  	const char *pm;
  	int err, i;
  
  	err = of_property_read_string(np, "phy-mode", &pm);
  	if (err < 0)
  		return err;
  
  	for (i = 0; i < ARRAY_SIZE(phy_modes); i++)
  		if (!strcasecmp(pm, phy_modes[i]))
  			return i;
  
  	return -ENODEV;
  }
  EXPORT_SYMBOL_GPL(of_get_phy_mode);
  
  /**
   * Search the device tree for the best MAC address to use.  'mac-address' is
   * checked first, because that is supposed to contain to "most recent" MAC
   * address. If that isn't set, then 'local-mac-address' is checked next,
   * because that is the default address.  If that isn't set, then the obsolete
   * 'address' is checked, just in case we're using an old device tree.
   *
   * Note that the 'address' property is supposed to contain a virtual address of
   * the register set, but some DTS files have redefined that property to be the
   * MAC address.
   *
   * All-zero MAC addresses are rejected, because those could be properties that
   * exist in the device tree, but were not set by U-Boot.  For example, the
   * DTS could define 'mac-address' and 'local-mac-address', with zero MAC
   * addresses.  Some older U-Boots only initialized 'local-mac-address'.  In
   * this case, the real MAC is in 'local-mac-address', and 'mac-address' exists
   * but is all zeros.
  */
  const void *of_get_mac_address(struct device_node *np)
  {
  	struct property *pp;
  
  	pp = of_find_property(np, "mac-address", NULL);
  	if (pp && (pp->length == 6) && is_valid_ether_addr(pp->value))
  		return pp->value;
  
  	pp = of_find_property(np, "local-mac-address", NULL);
  	if (pp && (pp->length == 6) && is_valid_ether_addr(pp->value))
  		return pp->value;
  
  	pp = of_find_property(np, "address", NULL);
  	if (pp && (pp->length == 6) && is_valid_ether_addr(pp->value))
  		return pp->value;
  
  	return NULL;
  }
  EXPORT_SYMBOL(of_get_mac_address);