From 639dba857aa554f2a78572adc4cf3c32de9ec2e2 Mon Sep 17 00:00:00 2001 From: Ansuel Smith Date: Tue, 30 Mar 2021 18:21:14 +0200 Subject: [PATCH 2/2] of_net: add mac-address-increment support Lots of embedded devices use the mac-address of other interface extracted from nvmem cells and increments it by one or two. Add two bindings to integrate this and directly use the right mac-address for the interface. Some example are some routers that use the gmac mac-address stored in the art partition and increments it by one for the wifi. mac-address-increment-byte bindings is used to tell what byte of the mac-address has to be increased (if not defined the last byte is increased) and mac-address-increment tells how much the byte decided early has to be increased. Signed-off-by: Ansuel Smith --- drivers/of/of_net.c | 59 ++++++++++++++++++++++++++++++++++----------- 1 file changed, 45 insertions(+), 14 deletions(-) --- a/drivers/of/of_net.c +++ b/drivers/of/of_net.c @@ -166,31 +166,56 @@ static int of_get_mac_address_mtd(struct * If a mtd-mac-address property exists, try to fetch the MAC address from the * specified mtd device. * + * DT can tell the system to increment the mac-address after is extracted by + * using: + * - mac-address-increment-byte to decide what byte to increase + * (if not defined is increased the last byte) + * - mac-address-increment to decide how much to increase. The value will + * not overflow to other bytes if the increment is over 255. + * (example 00:01:02:03:04:ff + 1 == 00:01:02:03:04:00) + * * Return: 0 on success and errno in case of error. */ int of_get_mac_address(struct device_node *np, u8 *addr) { + u32 inc_idx, mac_inc; int ret; + /* Check first if the increment byte is present and valid. + * If not set assume to increment the last byte if found. + */ + if (of_property_read_u32(np, "mac-address-increment-byte", &inc_idx)) + inc_idx = 5; + if (inc_idx < 3 || inc_idx > 5) + return -EINVAL; + if (!np) return -ENODEV; ret = of_get_mac_addr(np, "mac-address", addr); if (!ret) - return 0; + goto found; ret = of_get_mac_addr(np, "local-mac-address", addr); if (!ret) - return 0; + goto found; ret = of_get_mac_addr(np, "address", addr); if (!ret) - return 0; + goto found; ret = of_get_mac_address_mtd(np, addr); if (!ret) - return 0; + goto found; + + ret = of_get_mac_addr_nvmem(np, addr); + if (ret) + return ret; + +found: + if (!of_property_read_u32(np, "mac-address-increment", &mac_inc)) + addr[inc_idx] += mac_inc; - return of_get_mac_addr_nvmem(np, addr); + return ret; } EXPORT_SYMBOL(of_get_mac_address);