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 @@ -49,31 +49,36 @@ static void *of_get_mac_addr(struct devi
  24         return NULL;
  25  }
  26
  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)
  29  {
  30         int ret;
  31 -       const void *mac;
  32 +       void *mac;
  33         u8 nvmem_mac[ETH_ALEN];
  34         struct platform_device *pdev = of_find_device_by_node(np);
  35
  36 -       if (!pdev)
  37 -               return ERR_PTR(-ENODEV);
  38 +       if (!pdev) {
  39 +               *err = -ENODEV;
  40 +               return NULL;
  41 +       }
  42
  43         ret = nvmem_get_mac_address(&pdev->dev, &nvmem_mac);
  44         if (ret) {
  45                 put_device(&pdev->dev);
  46 -               return ERR_PTR(ret);
  47 +               *err = ret;
  48 +               return NULL;
  49         }
  50
  51         mac = devm_kmemdup(&pdev->dev, nvmem_mac, ETH_ALEN, GFP_KERNEL);
  52         put_device(&pdev->dev);
  53 -       if (!mac)
  54 -               return ERR_PTR(-ENOMEM);
  55 +       if (!mac) {
  56 +               *err = -ENOMEM;
  57 +               return NULL;
  58 +       }
  59
  60         return mac;
  61  }
  62
  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)
  65  {
  66  #ifdef CONFIG_MTD
  67         struct device_node *mtd_np = NULL;
  68 @@ -161,28 +166,54 @@ 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
  71   *
  72 + * DT can tell the system to increment the mac-address after is extracted by
  73 + * using:
  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)
  79 + *
  80   * Return: Will be a valid pointer on success and ERR_PTR in case of error.
  81  */
  82  const void *of_get_mac_address(struct device_node *np)
  83  {
  84 -       const void *addr;
  85 +       u32 inc_idx, mac_inc;
  86 +       int ret = 0;
  87 +       u8 *addr;
  88 +
  89 +       /* Check first if the increment byte is present and valid.
  90 +        * If not set assume to increment the last byte if found.
  91 +        */
  92 +       if (of_property_read_u32(np, "mac-address-increment-byte", &inc_idx))
  93 +               inc_idx = 5;
  94 +       if (inc_idx < 3 || inc_idx > 5)
  95 +               return ERR_PTR(-EINVAL);
  96
  97         addr = of_get_mac_addr(np, "mac-address");
  98         if (addr)
  99 -               return addr;
 100 +               goto found;
 101
 102         addr = of_get_mac_addr(np, "local-mac-address");
 103         if (addr)
 104 -               return addr;
 105 +               goto found;
 106
 107         addr = of_get_mac_addr(np, "address");
 108         if (addr)
 109 -               return addr;
 110 +               goto found;
 111
 112         addr = of_get_mac_address_mtd(np);
 113         if (addr)
 114 -               return addr;
 115 +               goto found;
 116 +
 117 +       addr = of_get_mac_addr_nvmem(np, &ret);
 118 +       if (ret)
 119 +               return ERR_PTR(ret);
 120 +
 121 +found:
 122 +       if (!of_property_read_u32(np, "mac-address-increment", &mac_inc))
 123 +               addr[inc_idx] += mac_inc;
 124
 125 -       return of_get_mac_addr_nvmem(np);
 126 +       return addr;
 127  }
 128  EXPORT_SYMBOL(of_get_mac_address);