package/boot/uboot-envtools/patches/102-fw_env-add-fallback-to-Linux-s-NVMEM-based-access.patch

   1 From 8142c4554ffaa927529f24427a35f7ee2861793a Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
   3 Date: Thu, 16 Jun 2022 20:59:03 +0200
   4 Subject: [PATCH] fw_env: add fallback to Linux's NVMEM based access
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 A new DT binding for describing environment data block has been added in
  10 Linux's commit 5db1c2dbc04c ("dt-bindings: nvmem: add U-Boot environment
  11 variables binding"). Once we get a proper Linux NVMEM driver it'll be
  12 possible to use Linux's binary interface for user-space as documented
  13 in the:
  14 https://www.kernel.org/doc/html/latest/driver-api/nvmem.html
  15
  16 This commits makes fw_env fallback to looking for a compatible NVMEM
  17 device in case config file isn't present. In a long term this may make
  18 config files redundant and avoid code (info) duplication.
  19
  20 Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
  21 ---
  22  tools/env/fw_env.c | 70 ++++++++++++++++++++++++++++++++++++++++++++--
  23  1 file changed, 67 insertions(+), 3 deletions(-)
  24
  25 --- a/tools/env/fw_env.c
  26 +++ b/tools/env/fw_env.c
  27 @@ -1713,6 +1713,67 @@ static int check_device_config(int dev)
  28         return rc;
  29  }
  30
  31 +static int find_nvmem_device(void)
  32 +{
  33 +       const char *path = "/sys/bus/nvmem/devices";
  34 +       struct dirent *dent;
  35 +       char *nvmem = NULL;
  36 +       char comp[256];
  37 +       char buf[32];
  38 +       int bytes;
  39 +       DIR *dir;
  40 +
  41 +       dir = opendir(path);
  42 +       if (!dir) {
  43 +               return -EIO;
  44 +       }
  45 +
  46 +       while (!nvmem && (dent = readdir(dir))) {
  47 +               FILE *fp;
  48 +
  49 +               if (!strcmp(dent->d_name, ".") || !strcmp(dent->d_name, "..")) {
  50 +                       continue;
  51 +               }
  52 +
  53 +               bytes = snprintf(comp, sizeof(comp), "%s/%s/of_node/compatible", path, dent->d_name);
  54 +               if (bytes < 0 || bytes == sizeof(comp)) {
  55 +                       continue;
  56 +               }
  57 +
  58 +               fp = fopen(comp, "r");
  59 +               if (!fp) {
  60 +                       continue;
  61 +               }
  62 +
  63 +               fread(buf, sizeof(buf), 1, fp);
  64 +
  65 +               if (!strcmp(buf, "u-boot,env")) {
  66 +                       bytes = asprintf(&nvmem, "%s/%s/nvmem", path, dent->d_name);
  67 +                       if (bytes < 0) {
  68 +                               nvmem = NULL;
  69 +                       }
  70 +               }
  71 +
  72 +               fclose(fp);
  73 +       }
  74 +
  75 +       closedir(dir);
  76 +
  77 +       if (nvmem) {
  78 +               struct stat s;
  79 +
  80 +               stat(nvmem, &s);
  81 +
  82 +               DEVNAME(0) = nvmem;
  83 +               DEVOFFSET(0) = 0;
  84 +               ENVSIZE(0) = s.st_size;
  85 +
  86 +               return 0;
  87 +       }
  88 +
  89 +       return -ENOENT;
  90 +}
  91 +
  92  static int parse_config(struct env_opts *opts)
  93  {
  94         int rc;
  95 @@ -1723,9 +1784,12 @@ static int parse_config(struct env_opts
  96  #if defined(CONFIG_FILE)
  97         /* Fills in DEVNAME(), ENVSIZE(), DEVESIZE(). Or don't. */
  98         if (get_config(opts->config_file)) {
  99 -               fprintf(stderr, "Cannot parse config file '%s': %m\n",
 100 -                       opts->config_file);
 101 -               return -1;
 102 +               if (find_nvmem_device()) {
 103 +                       fprintf(stderr, "Cannot parse config file '%s': %m\n",
 104 +                               opts->config_file);
 105 +                       fprintf(stderr, "Failed to find NVMEM device\n");
 106 +                       return -1;
 107 +               }
 108         }
 109  #else
 110         DEVNAME(0) = DEVICE1_NAME;