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 diff --git a/drivers/of/of_net.c b/drivers/of/of_net.c
  22 index f072e2509cc9..0dbd1f7ef396 100644
  23 --- a/drivers/of/of_net.c
  24 +++ b/drivers/of/of_net.c
  25 @@ -55,31 +55,36 @@ static void *of_get_mac_addr(struct device_node *np, const char *name)
  26         return NULL;
  27  }
  28
  29 -static const void *of_get_mac_addr_nvmem(struct device_node *np)
  30 +static void *of_get_mac_addr_nvmem(struct device_node *np, int *err)
  31  {
  32         int ret;
  33 -       const void *mac;
  34 +       void *mac;
  35         u8 nvmem_mac[ETH_ALEN];
  36         struct platform_device *pdev = of_find_device_by_node(np);
  37
  38 -       if (!pdev)
  39 -               return ERR_PTR(-ENODEV);
  40 +       if (!pdev) {
  41 +               *err = -ENODEV;
  42 +               return NULL;
  43 +       }
  44
  45         ret = nvmem_get_mac_address(&pdev->dev, &nvmem_mac);
  46         if (ret) {
  47                 put_device(&pdev->dev);
  48 -               return ERR_PTR(ret);
  49 +               *err = ret;
  50 +               return NULL;
  51         }
  52
  53         mac = devm_kmemdup(&pdev->dev, nvmem_mac, ETH_ALEN, GFP_KERNEL);
  54         put_device(&pdev->dev);
  55 -       if (!mac)
  56 -               return ERR_PTR(-ENOMEM);
  57 +       if (!mac) {
  58 +               *err = -ENOMEM;
  59 +               return NULL;
  60 +       }
  61
  62         return mac;
  63  }
  64
  65 -static const void *of_get_mac_address_mtd(struct device_node *np)
  66 +static void *of_get_mac_address_mtd(struct device_node *np)
  67  {
  68  #ifdef CONFIG_MTD
  69         struct device_node *mtd_np = NULL;
  70 @@ -167,28 +172,54 @@ static const void *of_get_mac_address_mtd(struct device_node *np)
  71   * If a mtd-mac-address property exists, try to fetch the MAC address from the
  72   * specified mtd device, and store it as a 'mac-address' property
  73   *
  74 + * DT can tell the system to increment the mac-address after is extracted by
  75 + * using:
  76 + * - mac-address-increment-byte to decide what byte to increase
  77 + *   (if not defined is increased the last byte)
  78 + * - mac-address-increment to decide how much to increase. The value will
  79 + *   not overflow to other bytes if the increment is over 255.
  80 + *   (example 00:01:02:03:04:ff + 1 == 00:01:02:03:04:00)
  81 + *
  82   * Return: Will be a valid pointer on success and ERR_PTR in case of error.
  83  */
  84  const void *of_get_mac_address(struct device_node *np)
  85  {
  86 -       const void *addr;
  87 +       u32 inc_idx, mac_inc;
  88 +       int ret = 0;
  89 +       u8 *addr;
  90 +
  91 +       /* Check first if the increment byte is present and valid.
  92 +        * If not set assume to increment the last byte if found.
  93 +        */
  94 +       if (of_property_read_u32(np, "mac-address-increment-byte", &inc_idx))
  95 +               inc_idx = 5;
  96 +       if (inc_idx < 3 || inc_idx > 5)
  97 +               return ERR_PTR(-EINVAL);
  98
  99         addr = of_get_mac_addr(np, "mac-address");
 100         if (addr)
 101 -               return addr;
 102 +               goto found;
 103
 104         addr = of_get_mac_addr(np, "local-mac-address");
 105         if (addr)
 106 -               return addr;
 107 +               goto found;
 108
 109         addr = of_get_mac_addr(np, "address");
 110         if (addr)
 111 -               return addr;
 112 +               goto found;
 113
 114         addr = of_get_mac_address_mtd(np);
 115         if (addr)
 116 -               return addr;
 117 +               goto found;
 118 +
 119 +       addr = of_get_mac_addr_nvmem(np, &ret);
 120 +       if (ret)
 121 +               return ERR_PTR(ret);
 122 +
 123 +found:
 124 +       if (!of_property_read_u32(np, "mac-address-increment", &mac_inc))
 125 +               addr[inc_idx] += mac_inc;
 126
 127 -       return of_get_mac_addr_nvmem(np);
 128 +       return addr;
 129  }
 130  EXPORT_SYMBOL(of_get_mac_address);
 131 --
 132 2.30.2
 133