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);
146
147 /**
148 * of_get_ethdev_address()
149 * @np: Caller's Device Node
150 * @dev: Pointer to netdevice which address will be updated
151 *
152 * Search the device tree for the best MAC address to use.
153 * If found set @dev->dev_addr to that address.
154 *
155 * See documentation of of_get_mac_address() for more information on how
156 * the best address is determined.
157 *
158 * Return: 0 on success and errno in case of error.
159 */
160 int of_get_ethdev_address(struct device_node *np, struct net_device *dev)
161 {
162 u8 addr[ETH_ALEN];
163 int ret;
164
165 ret = of_get_mac_address(np, addr);
166 if (!ret)
167 eth_hw_addr_set(dev, addr);
168 return ret;
169 }
170 EXPORT_SYMBOL(of_get_ethdev_address);
171
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