From: Rafał Miłecki rafal@milecki.pl

A new DT binding for describing environment data block has been added in Linux's commit 5db1c2dbc04c ("dt-bindings: nvmem: add U-Boot environment variables binding"). Once we get a proper Linux NVMEM driver it'll be possible to use Linux's binary interface for user-space as documented in the: https://www.kernel.org/doc/html/latest/driver-api/nvmem.html

This commits makes fw_env fallback to looking for a compatible NVMEM device in case config file isn't present. In a long term this may make config files redundant and avoid code (info) duplication.

Signed-off-by: Rafał Miłecki rafal@milecki.pl --- tools/env/fw_env.c | 70 ++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 67 insertions(+), 3 deletions(-)

diff --git a/tools/env/fw_env.c b/tools/env/fw_env.c index 31afef6f3b..be77bbf054 100644 --- a/tools/env/fw_env.c +++ b/tools/env/fw_env.c @@ -1713,6 +1713,67 @@ static int check_device_config(int dev) return rc; }

+static int find_nvmem_device(void) +{ + const char *path = "/sys/bus/nvmem/devices"; + struct dirent *dent; + char *nvmem = NULL; + char comp[256]; + char buf[32]; + int bytes; + DIR *dir; + + dir = opendir(path); + if (!dir) { + return -EIO; + } + + while (!nvmem && (dent = readdir(dir))) { + FILE *fp; + + if (!strcmp(dent->d_name, ".") || !strcmp(dent->d_name, "..")) { + continue; + } + + bytes = snprintf(comp, sizeof(comp), "%s/%s/of_node/compatible", path, dent->d_name); + if (bytes < 0 || bytes == sizeof(comp)) { + continue; + } + + fp = fopen(comp, "r"); + if (!fp) { + continue; + } + + fread(buf, sizeof(buf), 1, fp); + + if (!strcmp(buf, "u-boot,env")) { + bytes = asprintf(&nvmem, "%s/%s/nvmem", path, dent->d_name); + if (bytes < 0) { + nvmem = NULL; + } + } + + fclose(fp); + } + + closedir(dir); + + if (nvmem) { + struct stat s; + + stat(nvmem, &s); + + DEVNAME(0) = nvmem; + DEVOFFSET(0) = 0; + ENVSIZE(0) = s.st_size; + + return 0; + } + + return -ENOENT; +} + static int parse_config(struct env_opts *opts) { int rc; @@ -1723,9 +1784,12 @@ static int parse_config(struct env_opts *opts) #if defined(CONFIG_FILE) /* Fills in DEVNAME(), ENVSIZE(), DEVESIZE(). Or don't. */ if (get_config(opts->config_file)) { - fprintf(stderr, "Cannot parse config file '%s': %m\n", - opts->config_file); - return -1; + if (find_nvmem_device()) { + fprintf(stderr, "Cannot parse config file '%s': %m\n", + opts->config_file); + fprintf(stderr, "Failed to find NVMEM device\n"); + return -1; + } } #else DEVNAME(0) = DEVICE1_NAME;