1 From 639dba857aa554f2a78572adc4cf3c32de9ec2e2 Mon Sep 17 00:00:00 2001
2 From: Ansuel Smith <ansuelsmth@gmail.com>
3 Date: Tue, 30 Mar 2021 18:21:14 +0200
4 Subject: [PATCH 2/2] of_net: add mac-address-increment support
6 Lots of embedded devices use the mac-address of other interface
7 extracted from nvmem cells and increments it by one or two. Add two
8 bindings to integrate this and directly use the right mac-address for
9 the interface. Some example are some routers that use the gmac
10 mac-address stored in the art partition and increments it by one for the
11 wifi. mac-address-increment-byte bindings is used to tell what byte of
12 the mac-address has to be increased (if not defined the last byte is
13 increased) and mac-address-increment tells how much the byte decided
14 early has to be increased.
16 Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
18 drivers/of/of_net.c | 59 ++++++++++++++++++++++++++++++++++-----------
19 1 file changed, 45 insertions(+), 14 deletions(-)
21 --- a/drivers/of/of_net.c
22 +++ b/drivers/of/of_net.c
23 @@ -55,31 +55,36 @@ static void *of_get_mac_addr(struct devi
27 -static const void *of_get_mac_addr_nvmem(struct device_node *np)
28 +static void *of_get_mac_addr_nvmem(struct device_node *np, int *err)
33 u8 nvmem_mac[ETH_ALEN];
34 struct platform_device *pdev = of_find_device_by_node(np);
37 - return ERR_PTR(-ENODEV);
43 ret = nvmem_get_mac_address(&pdev->dev, &nvmem_mac);
45 put_device(&pdev->dev);
46 - return ERR_PTR(ret);
51 mac = devm_kmemdup(&pdev->dev, nvmem_mac, ETH_ALEN, GFP_KERNEL);
52 put_device(&pdev->dev);
54 - return ERR_PTR(-ENOMEM);
63 -static const void *of_get_mac_address_mtd(struct device_node *np)
64 +static void *of_get_mac_address_mtd(struct device_node *np)
67 struct device_node *mtd_np = NULL;
68 @@ -167,28 +172,54 @@ free:
69 * If a mtd-mac-address property exists, try to fetch the MAC address from the
70 * specified mtd device, and store it as a 'mac-address' property
72 + * DT can tell the system to increment the mac-address after is extracted by
74 + * - mac-address-increment-byte to decide what byte to increase
75 + * (if not defined is increased the last byte)
76 + * - mac-address-increment to decide how much to increase. The value will
77 + * not overflow to other bytes if the increment is over 255.
78 + * (example 00:01:02:03:04:ff + 1 == 00:01:02:03:04:00)
80 * Return: Will be a valid pointer on success and ERR_PTR in case of error.
82 const void *of_get_mac_address(struct device_node *np)
85 + u32 inc_idx, mac_inc;
89 + /* Check first if the increment byte is present and valid.
90 + * If not set assume to increment the last byte if found.
92 + if (of_property_read_u32(np, "mac-address-increment-byte", &inc_idx))
94 + if (inc_idx < 3 || inc_idx > 5)
95 + return ERR_PTR(-EINVAL);
97 addr = of_get_mac_addr(np, "mac-address");
102 addr = of_get_mac_addr(np, "local-mac-address");
107 addr = of_get_mac_addr(np, "address");
112 addr = of_get_mac_address_mtd(np);
117 + addr = of_get_mac_addr_nvmem(np, &ret);
119 + return ERR_PTR(ret);
122 + if (!of_property_read_u32(np, "mac-address-increment", &mac_inc))
123 + addr[inc_idx] += mac_inc;
125 - return of_get_mac_addr_nvmem(np);
128 EXPORT_SYMBOL(of_get_mac_address);