target/linux/generic/pending-5.4/682-of_net-add-mac-address-increment-support.patch

   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
   5
   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.
  15
  16 Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
  17 ---
  18  drivers/of/of_net.c | 59 ++++++++++++++++++++++++++++++++++-----------
  19  1 file changed, 45 insertions(+), 14 deletions(-)
  20
  21 --- a/drivers/of/of_net.c
  22 +++ b/drivers/of/of_net.c
  23 @@ -165,31 +165,56 @@ static int of_get_mac_address_mtd(struct
  24   * If a mtd-mac-address property exists, try to fetch the MAC address from the
  25   * specified mtd device.
  26   *
  27 + * DT can tell the system to increment the mac-address after is extracted by
  28 + * using:
  29 + * - mac-address-increment-byte to decide what byte to increase
  30 + *   (if not defined is increased the last byte)
  31 + * - mac-address-increment to decide how much to increase. The value will
  32 + *   not overflow to other bytes if the increment is over 255.
  33 + *   (example 00:01:02:03:04:ff + 1 == 00:01:02:03:04:00)
  34 + *
  35   * Return: 0 on success and errno in case of error.
  36  */
  37  int of_get_mac_address(struct device_node *np, u8 *addr)
  38  {
  39 +       u32 inc_idx, mac_inc;
  40         int ret;
  41
  42 +       /* Check first if the increment byte is present and valid.
  43 +        * If not set assume to increment the last byte if found.
  44 +        */
  45 +       if (of_property_read_u32(np, "mac-address-increment-byte", &inc_idx))
  46 +               inc_idx = 5;
  47 +       if (inc_idx < 3 || inc_idx > 5)
  48 +               return -EINVAL;
  49 +
  50         if (!np)
  51                 return -ENODEV;
  52
  53         ret = of_get_mac_addr(np, "mac-address", addr);
  54         if (!ret)
  55 -               return 0;
  56 +               goto found;
  57
  58         ret = of_get_mac_addr(np, "local-mac-address", addr);
  59         if (!ret)
  60 -               return 0;
  61 +               goto found;
  62
  63         ret = of_get_mac_addr(np, "address", addr);
  64         if (!ret)
  65 -               return 0;
  66 +               goto found;
  67
  68         ret = of_get_mac_address_mtd(np, addr);
  69         if (!ret)
  70 -               return 0;
  71 +               goto found;
  72 +
  73 +       ret = of_get_mac_addr_nvmem(np, addr);
  74 +       if (ret)
  75 +               return ret;
  76 +
  77 +found:
  78 +       if (!of_property_read_u32(np, "mac-address-increment", &mac_inc))
  79 +               addr[inc_idx] += mac_inc;
  80
  81 -       return of_get_mac_addr_nvmem(np, addr);
  82 +       return ret;
  83  }
  84  EXPORT_SYMBOL(of_get_mac_address);