/*
 * 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/nvmem-consumer.h>
#include <linux/of_net.h>
#include <linux/phy.h>
#include <linux/export.h>

/**
 * 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' or
 * 'phy-connection-type', 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)
		err = of_property_read_string(np, "phy-connection-type", &pm);
	if (err < 0)
		return err;

	for (i = 0; i < PHY_INTERFACE_MODE_MAX; i++)
		if (!strcasecmp(pm, phy_modes(i)))
			return i;

	return -ENODEV;
}
EXPORT_SYMBOL_GPL(of_get_phy_mode);

static const void *of_get_mac_addr(struct device_node *np, const char *name)
{
	struct property *pp = of_find_property(np, name, NULL);

	if (pp && pp->length == ETH_ALEN && is_valid_ether_addr(pp->value))
		return pp->value;
	return NULL;
}

/**
 * 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)
{
	const void *addr;

	addr = of_get_mac_addr(np, "mac-address");
	if (addr)
		return addr;

	addr = of_get_mac_addr(np, "local-mac-address");
	if (addr)
		return addr;

	return of_get_mac_addr(np, "address");
}
EXPORT_SYMBOL(of_get_mac_address);

/**
 * Obtain the MAC address from an nvmem provider named 'mac-address' through
 * device tree.
 * On success, copies the new address into memory pointed to by addr and
 * returns 0. Returns a negative error code otherwise.
 * @np:		Device tree node containing the nvmem-cells phandle
 * @addr:	Pointer to receive the MAC address using ether_addr_copy()
 */
int of_get_nvmem_mac_address(struct device_node *np, void *addr)
{
	struct nvmem_cell *cell;
	const void *mac;
	size_t len;
	int ret;

	cell = of_nvmem_cell_get(np, "mac-address");
	if (IS_ERR(cell))
		return PTR_ERR(cell);

	mac = nvmem_cell_read(cell, &len);

	nvmem_cell_put(cell);

	if (IS_ERR(mac))
		return PTR_ERR(mac);

	if (len < ETH_ALEN || !is_valid_ether_addr(mac)) {
		ret = -EINVAL;
	} else {
		ether_addr_copy(addr, mac);
		ret = 0;
	}

	kfree(mac);

	return ret;
}
EXPORT_SYMBOL(of_get_nvmem_mac_address);