LXR linux/drivers/of/of

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * OF helpers for network devices.
   4 *
   5 * Initially copied out of arch/powerpc/kernel/prom_parse.c
   6 */
   7#include <linux/etherdevice.h>
   8#include <linux/kernel.h>
   9#include <linux/of_net.h>
  10#include <linux/of_platform.h>
  11#include <linux/phy.h>
  12#include <linux/export.h>
  13#include <linux/device.h>
  14#include <linux/nvmem-consumer.h>
  15
  16/**
  17 * of_get_phy_mode - Get phy mode for given device_node
  18 * @np: Pointer to the given device_node
  19 * @interface: Pointer to the result
  20 *
  21 * The function gets phy interface string from property 'phy-mode' or
  22 * 'phy-connection-type'. The index in phy_modes table is set in
  23 * interface and 0 returned. In case of error interface is set to
  24 * PHY_INTERFACE_MODE_NA and an errno is returned, e.g. -ENODEV.
  25 */
  26int of_get_phy_mode(struct device_node *np, phy_interface_t *interface)
  27{
  28        const char *pm;
  29        int err, i;
  30
  31        *interface = PHY_INTERFACE_MODE_NA;
  32
  33        err = of_property_read_string(np, "phy-mode", &pm);
  34        if (err < 0)
  35                err = of_property_read_string(np, "phy-connection-type", &pm);
  36        if (err < 0)
  37                return err;
  38
  39        for (i = 0; i < PHY_INTERFACE_MODE_MAX; i++)
  40                if (!strcasecmp(pm, phy_modes(i))) {
  41                        *interface = i;
  42                        return 0;
  43                }
  44
  45        return -ENODEV;
  46}
  47EXPORT_SYMBOL_GPL(of_get_phy_mode);
  48
  49static int of_get_mac_addr(struct device_node *np, const char *name, u8 *addr)
  50{
  51        struct property *pp = of_find_property(np, name, NULL);
  52
  53        if (pp && pp->length == ETH_ALEN && is_valid_ether_addr(pp->value)) {
  54                memcpy(addr, pp->value, ETH_ALEN);
  55                return 0;
  56        }
  57        return -ENODEV;
  58}
  59
  60static int of_get_mac_addr_nvmem(struct device_node *np, u8 *addr)
  61{
  62        struct platform_device *pdev = of_find_device_by_node(np);
  63        struct nvmem_cell *cell;
  64        const void *mac;
  65        size_t len;
  66        int ret;
  67
  68        /* Try lookup by device first, there might be a nvmem_cell_lookup
  69         * associated with a given device.
  70         */
  71        if (pdev) {
  72                ret = nvmem_get_mac_address(&pdev->dev, addr);
  73                put_device(&pdev->dev);
  74                return ret;
  75        }
  76
  77        cell = of_nvmem_cell_get(np, "mac-address");
  78        if (IS_ERR(cell))
  79                return PTR_ERR(cell);
  80
  81        mac = nvmem_cell_read(cell, &len);
  82        nvmem_cell_put(cell);
  83
  84        if (IS_ERR(mac))
  85                return PTR_ERR(mac);
  86
  87        if (len != ETH_ALEN || !is_valid_ether_addr(mac)) {
  88                kfree(mac);
  89                return -EINVAL;
  90        }
  91
  92        memcpy(addr, mac, ETH_ALEN);
  93        kfree(mac);
  94
  95        return 0;
  96}
  97
  98/**
  99 * of_get_mac_address()
 100 * @np:         Caller's Device Node
 101 * @addr:       Pointer to a six-byte array for the result
 102 *
 103 * Search the device tree for the best MAC address to use.  'mac-address' is
 104 * checked first, because that is supposed to contain to "most recent" MAC
 105 * address. If that isn't set, then 'local-mac-address' is checked next,
 106 * because that is the default address. If that isn't set, then the obsolete
 107 * 'address' is checked, just in case we're using an old device tree. If any
 108 * of the above isn't set, then try to get MAC address from nvmem cell named
 109 * 'mac-address'.
 110 *
 111 * Note that the 'address' property is supposed to contain a virtual address of
 112 * the register set, but some DTS files have redefined that property to be the
 113 * MAC address.
 114 *
 115 * All-zero MAC addresses are rejected, because those could be properties that
 116 * exist in the device tree, but were not set by U-Boot.  For example, the
 117 * DTS could define 'mac-address' and 'local-mac-address', with zero MAC
 118 * addresses.  Some older U-Boots only initialized 'local-mac-address'.  In
 119 * this case, the real MAC is in 'local-mac-address', and 'mac-address' exists
 120 * but is all zeros.
 121 *
 122 * Return: 0 on success and errno in case of error.
 123*/
 124int of_get_mac_address(struct device_node *np, u8 *addr)
 125{
 126        int ret;
 127
 128        if (!np)
 129                return -ENODEV;
 130
 131        ret = of_get_mac_addr(np, "mac-address", addr);
 132        if (!ret)
 133                return 0;
 134
 135        ret = of_get_mac_addr(np, "local-mac-address", addr);
 136        if (!ret)
 137                return 0;
 138
 139        ret = of_get_mac_addr(np, "address", addr);
 140        if (!ret)
 141                return 0;
 142
 143        return of_get_mac_addr_nvmem(np, addr);
 144}
 145EXPORT_SYMBOL(of_get_mac_address);
 146