From 844c273286f328acf0dab5fbd5d864366b4904dc Mon Sep 17 00:00:00 2001 From: Ansuel Smith Date: Tue, 30 Mar 2021 18:21:14 +0200 Subject: [PATCH] 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 | 43 +++++++++++++++++++++++++++++++++++++++---- 1 file changed, 39 insertions(+), 4 deletions(-) --- a/drivers/of/of_net.c +++ b/drivers/of/of_net.c @@ -115,27 +115,62 @@ static int of_get_mac_addr_nvmem(struct * this case, the real MAC is in 'local-mac-address', and 'mac-address' exists * but is all zeros. * + * 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 + * overflow to other bytes if the increment is over 255 or the total + * increment will exceed 255 of the current byte. + * (example 00:01:02:03:04:ff + 1 == 00:01:02:03:05:00) + * (example 00:01:02:03:04:fe + 5 == 00:01:02:03:05:03) + * * 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, mac_val; 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_addr_nvmem(np, addr); + if (ret) + return ret; + +found: + if (!of_property_read_u32(np, "mac-address-increment", &mac_inc)) { + /* Convert to a contiguous value */ + mac_val = (addr[3] << 16) + (addr[4] << 8) + addr[5]; + mac_val += mac_inc << 8 * (5-inc_idx); + + /* Apply the incremented value handling overflow case */ + addr[3] = (mac_val >> 16) & 0xff; + addr[4] = (mac_val >> 8) & 0xff; + addr[5] = (mac_val >> 0) & 0xff; + } - return of_get_mac_addr_nvmem(np, addr); + return ret; } EXPORT_SYMBOL(of_get_mac_address); e1828bde5b50bb08205639f6f (plain) 
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