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 */
of_get_phy_mode(struct device_node * np,phy_interface_t * interface)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
of_get_mac_addr(struct device_node * np,const char * name)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
of_get_mac_addr_nvmem(struct device_node * np)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 */
of_get_mac_address(struct device_node * np)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);
122