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
  15 /**
  16  * of_get_phy_mode - Get phy mode for given device_node
  17  * @np: Pointer to the given device_node
  18  * @interface: Pointer to the result
  19  *
  20  * The function gets phy interface string from property 'phy-mode' or
  21  * 'phy-connection-type'. The index in phy_modes table is set in
  22  * interface and 0 returned. In case of error interface is set to
  23  * PHY_INTERFACE_MODE_NA and an errno is returned, e.g. -ENODEV.
  24  */
  25 int of_get_phy_mode(struct device_node *np, phy_interface_t *interface)
  26 {
  27         const char *pm;
  28         int err, i;
  29
  30         *interface = PHY_INTERFACE_MODE_NA;
  31
  32         err = of_property_read_string(np, "phy-mode", &pm);
  33         if (err < 0)
  34                 err = of_property_read_string(np, "phy-connection-type", &pm);
  35         if (err < 0)
  36                 return err;
  37
  38         for (i = 0; i < PHY_INTERFACE_MODE_MAX; i++)
  39                 if (!strcasecmp(pm, phy_modes(i))) {
  40                         *interface = i;
  41                         return 0;
  42                 }
  43
  44         return -ENODEV;
  45 }
  46 EXPORT_SYMBOL_GPL(of_get_phy_mode);
  47
  48 static const void *of_get_mac_addr(struct device_node *np, const char *name)
  49 {
  50         struct property *pp = of_find_property(np, name, NULL);
  51
  52         if (pp && pp->length == ETH_ALEN && is_valid_ether_addr(pp->value))
  53                 return pp->value;
  54         return NULL;
  55 }
  56
  57 static const void *of_get_mac_addr_nvmem(struct device_node *np)
  58 {
  59         int ret;
  60         const void *mac;
  61         u8 nvmem_mac[ETH_ALEN];
  62         struct platform_device *pdev = of_find_device_by_node(np);
  63
  64         if (!pdev)
  65                 return ERR_PTR(-ENODEV);
  66
  67         ret = nvmem_get_mac_address(&pdev->dev, &nvmem_mac);
  68         if (ret) {
  69                 put_device(&pdev->dev);
  70                 return ERR_PTR(ret);
  71         }
  72
  73         mac = devm_kmemdup(&pdev->dev, nvmem_mac, ETH_ALEN, GFP_KERNEL);
  74         put_device(&pdev->dev);
  75         if (!mac)
  76                 return ERR_PTR(-ENOMEM);
  77
  78         return mac;
  79 }
  80
  81 /**
  82  * Search the device tree for the best MAC address to use.  'mac-address' is
  83  * checked first, because that is supposed to contain to "most recent" MAC
  84  * address. If that isn't set, then 'local-mac-address' is checked next,
  85  * because that is the default address. If that isn't set, then the obsolete
  86  * 'address' is checked, just in case we're using an old device tree. If any
  87  * of the above isn't set, then try to get MAC address from nvmem cell named
  88  * 'mac-address'.
  89  *
  90  * Note that the 'address' property is supposed to contain a virtual address of
  91  * the register set, but some DTS files have redefined that property to be the
  92  * MAC address.
  93  *
  94  * All-zero MAC addresses are rejected, because those could be properties that
  95  * exist in the device tree, but were not set by U-Boot.  For example, the
  96  * DTS could define 'mac-address' and 'local-mac-address', with zero MAC
  97  * addresses.  Some older U-Boots only initialized 'local-mac-address'.  In
  98  * this case, the real MAC is in 'local-mac-address', and 'mac-address' exists
  99  * but is all zeros.
 100  *
 101  * Return: Will be a valid pointer on success and ERR_PTR in case of error.
 102 */
 103 const void *of_get_mac_address(struct device_node *np)
 104 {
 105         const void *addr;
 106
 107         addr = of_get_mac_addr(np, "mac-address");
 108         if (addr)
 109                 return addr;
 110
 111         addr = of_get_mac_addr(np, "local-mac-address");
 112         if (addr)
 113                 return addr;
 114
 115         addr = of_get_mac_addr(np, "address");
 116         if (addr)
 117                 return addr;
 118
 119         return of_get_mac_addr_nvmem(np);
 120 }
 121 EXPORT_SYMBOL(of_get_mac_address);