drivers/of/of_net.c

   1 /*
   2  * OF helpers for network devices.
   3  *
   4  * This file is released under the GPLv2
   5  *
   6  * Initially copied out of arch/powerpc/kernel/prom_parse.c
   7  */
   8 #include <linux/etherdevice.h>
   9 #include <linux/kernel.h>
  10 #include <linux/nvmem-consumer.h>
  11 #include <linux/of_net.h>
  12 #include <linux/phy.h>
  13 #include <linux/export.h>
  14
  15 /**
  16  * of_get_phy_mode - Get phy mode for given device_node
  17  * @np: Pointer to the given device_node
  18  *
  19  * The function gets phy interface string from property 'phy-mode' or
  20  * 'phy-connection-type', and return its index in phy_modes table, or errno in
  21  * error case.
  22  */
  23 int of_get_phy_mode(struct device_node *np)
  24 {
  25         const char *pm;
  26         int err, i;
  27
  28         err = of_property_read_string(np, "phy-mode", &pm);
  29         if (err < 0)
  30                 err = of_property_read_string(np, "phy-connection-type", &pm);
  31         if (err < 0)
  32                 return err;
  33
  34         for (i = 0; i < PHY_INTERFACE_MODE_MAX; i++)
  35                 if (!strcasecmp(pm, phy_modes(i)))
  36                         return i;
  37
  38         return -ENODEV;
  39 }
  40 EXPORT_SYMBOL_GPL(of_get_phy_mode);
  41
  42 static const void *of_get_mac_addr(struct device_node *np, const char *name)
  43 {
  44         struct property *pp = of_find_property(np, name, NULL);
  45
  46         if (pp && pp->length == ETH_ALEN && is_valid_ether_addr(pp->value))
  47                 return pp->value;
  48         return NULL;
  49 }
  50
  51 /**
  52  * Search the device tree for the best MAC address to use.  'mac-address' is
  53  * checked first, because that is supposed to contain to "most recent" MAC
  54  * address. If that isn't set, then 'local-mac-address' is checked next,
  55  * because that is the default address.  If that isn't set, then the obsolete
  56  * 'address' is checked, just in case we're using an old device tree.
  57  *
  58  * Note that the 'address' property is supposed to contain a virtual address of
  59  * the register set, but some DTS files have redefined that property to be the
  60  * MAC address.
  61  *
  62  * All-zero MAC addresses are rejected, because those could be properties that
  63  * exist in the device tree, but were not set by U-Boot.  For example, the
  64  * DTS could define 'mac-address' and 'local-mac-address', with zero MAC
  65  * addresses.  Some older U-Boots only initialized 'local-mac-address'.  In
  66  * this case, the real MAC is in 'local-mac-address', and 'mac-address' exists
  67  * but is all zeros.
  68 */
  69 const void *of_get_mac_address(struct device_node *np)
  70 {
  71         const void *addr;
  72
  73         addr = of_get_mac_addr(np, "mac-address");
  74         if (addr)
  75                 return addr;
  76
  77         addr = of_get_mac_addr(np, "local-mac-address");
  78         if (addr)
  79                 return addr;
  80
  81         return of_get_mac_addr(np, "address");
  82 }
  83 EXPORT_SYMBOL(of_get_mac_address);
  84
  85 /**
  86  * Obtain the MAC address from an nvmem provider named 'mac-address' through
  87  * device tree.
  88  * On success, copies the new address into memory pointed to by addr and
  89  * returns 0. Returns a negative error code otherwise.
  90  * @np:         Device tree node containing the nvmem-cells phandle
  91  * @addr:       Pointer to receive the MAC address using ether_addr_copy()
  92  */
  93 int of_get_nvmem_mac_address(struct device_node *np, void *addr)
  94 {
  95         struct nvmem_cell *cell;
  96         const void *mac;
  97         size_t len;
  98         int ret;
  99
 100         cell = of_nvmem_cell_get(np, "mac-address");
 101         if (IS_ERR(cell))
 102                 return PTR_ERR(cell);
 103
 104         mac = nvmem_cell_read(cell, &len);
 105
 106         nvmem_cell_put(cell);
 107
 108         if (IS_ERR(mac))
 109                 return PTR_ERR(mac);
 110
 111         if (len < ETH_ALEN || !is_valid_ether_addr(mac)) {
 112                 ret = -EINVAL;
 113         } else {
 114                 ether_addr_copy(addr, mac);
 115                 ret = 0;
 116         }
 117
 118         kfree(mac);
 119
 120         return ret;
 121 }
 122 EXPORT_SYMBOL(of_get_nvmem_mac_address);