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- From 8142c4554ffaa927529f24427a35f7ee2861793a Mon Sep 17 00:00:00 2001
- From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <[email protected]>
- Date: Thu, 16 Jun 2022 20:59:03 +0200
- Subject: [PATCH] fw_env: add fallback to Linux's NVMEM based access
- MIME-Version: 1.0
- Content-Type: text/plain; charset=UTF-8
- Content-Transfer-Encoding: 8bit
- 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 <[email protected]>
- ---
- tools/env/fw_env.c | 70 ++++++++++++++++++++++++++++++++++++++++++++--
- 1 file changed, 67 insertions(+), 3 deletions(-)
- --- 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
- #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;
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