drivers/of/of_net.c

   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  */
  26 int 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 }
  47 EXPORT_SYMBOL_GPL(of_get_phy_mode);
  48
  49 static 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
  60 static 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 */
 124 int 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 }
 145 EXPORT_SYMBOL(of_get_mac_address);