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 *
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 static const void *of_get_mac_addr_nvmem(struct device_node *np)
52 {
53 int ret;
54 const void *mac;
55 u8 nvmem_mac[ETH_ALEN];
56 struct platform_device *pdev = of_find_device_by_node(np);
57
58 if (!pdev)
59 return ERR_PTR(-ENODEV);
60
61 ret = nvmem_get_mac_address(&pdev->dev, &nvmem_mac);
62 if (ret) {
63 put_device(&pdev->dev);
64 return ERR_PTR(ret);
65 }
66
67 mac = devm_kmemdup(&pdev->dev, nvmem_mac, ETH_ALEN, GFP_KERNEL);
68 put_device(&pdev->dev);
69 if (!mac)
70 return ERR_PTR(-ENOMEM);
71
72 return mac;
73 }
74
75 /**
76 * Search the device tree for the best MAC address to use. 'mac-address' is
77 * checked first, because that is supposed to contain to "most recent" MAC
78 * address. If that isn't set, then 'local-mac-address' is checked next,
79 * because that is the default address. If that isn't set, then the obsolete
80 * 'address' is checked, just in case we're using an old device tree. If any
81 * of the above isn't set, then try to get MAC address from nvmem cell named
82 * 'mac-address'.
83 *
84 * Note that the 'address' property is supposed to contain a virtual address of
85 * the register set, but some DTS files have redefined that property to be the
86 * MAC address.
87 *
88 * All-zero MAC addresses are rejected, because those could be properties that
89 * exist in the device tree, but were not set by U-Boot. For example, the
90 * DTS could define 'mac-address' and 'local-mac-address', with zero MAC
91 * addresses. Some older U-Boots only initialized 'local-mac-address'. In
92 * this case, the real MAC is in 'local-mac-address', and 'mac-address' exists
93 * but is all zeros.
94 *
95 * Return: Will be a valid pointer on success and ERR_PTR in case of error.
96 */
97 const void *of_get_mac_address(struct device_node *np)
98 {
99 const void *addr;
100
101 addr = of_get_mac_addr(np, "mac-address");
102 if (addr)
103 return addr;
104
105 addr = of_get_mac_addr(np, "local-mac-address");
106 if (addr)
107 return addr;
108
109 addr = of_get_mac_addr(np, "address");
110 if (addr)
111 return addr;
112
113 return of_get_mac_addr_nvmem(np);
114 }
115 EXPORT_SYMBOL(of_get_mac_address);