Re: [PATCH v2 3/3] fdt: introduce fsapply command

["Lothar Waßmann" <LW@KARO-electronics.de>]

Hi,

On Fri, 10 Feb 2023 11:02:13 +0000 Andre Przywara wrote:
> Explicitly specifying the exact filenames of devicetree overlays files
> on a U-Boot command line can be quite tedious for users, especially
> when it should be made persistent for every boot.
> 
> To simplify the task of applying (custom) DT overlays, introduce a
> "fdt fsapply" subcommand, that iterates a given directory in any
> supported filesystem, and tries to apply every .dtbo file found it
> there.
> 
> This allows users to simply drop a DT overlay file into a magic
> directory, and it will be applied on the next boot automatically,
> by the virtue of just a generic U-Boot command call.
> 
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
>  cmd/fdt.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 87 insertions(+)
> 
> diff --git a/cmd/fdt.c b/cmd/fdt.c
> index 1972490bdc2..00f92dbbb5d 100644
> --- a/cmd/fdt.c
> +++ b/cmd/fdt.c
> @@ -127,6 +129,81 @@ static int fdt_get_header_value(int argc, char *const argv[])
>  	return CMD_RET_FAILURE;
>  }
>  
> +#ifdef CONFIG_OF_LIBFDT_OVERLAY
> +static int apply_all_overlays(const char *ifname, const char *dev_part_str,
> +			      const char *dirname)
> +{
> +	unsigned long addr;
> +	struct fdt_header *dtbo;
> +	const char *addr_str;
> +	struct fs_dir_stream *dirs;
> +	struct fs_dirent *dent;
> +	char fname[256], *name_beg;
> +	int ret;
> +
> +	addr_str = env_get("fdtoverlay_addr_r");
> +	if (!addr_str) {
> +		printf("Invalid fdtoverlay_addr_r for loading overlays\n");
> +		return CMD_RET_FAILURE;
> +	}
> +	addr = hextoul(addr_str, NULL);
> +
> +	ret = fs_set_blk_dev(ifname, dev_part_str, FS_TYPE_ANY);
> +	if (ret)
> +		return CMD_RET_FAILURE;
> +
> +	if (!dirname)
> +		dirname = "/";
> +	dirs = fs_opendir(dirname);
> +	if (!dirs) {
> +		printf("Cannot find directory \"%s\"\n", dirname);
> +		return CMD_RET_FAILURE;
> +	}
> +
> +	strcpy(fname, dirname);
> +	name_beg = strchr(fname, 0);
> +	if (name_beg[-1] != '/')
> +		*name_beg++ = '/';
> +
> +	dtbo = map_sysmem(addr, 0);
> +	while ((dent = fs_readdir(dirs))) {
> +		loff_t size = 0;
> +
> +		if (dent->type == FS_DT_DIR)
> +			continue;
> +
> +		if (strcmp(dent->name + strlen(dent->name) - 5, ".dtbo"))
> +			continue;
> +
> +		printf("%s: ", dent->name);
> +		strcpy(name_beg, dent->name);
> +		fs_set_blk_dev(ifname, dev_part_str, FS_TYPE_ANY);
> +		if (dent->size > SZ_2M)
> +			size = SZ_2M;
> +		else
> +			size = dent->size;
> +		ret = fs_read(fname, addr, 0, size, &size);
> +		if (ret) {
> +			printf("  errno: %d\n", ret);
> +			continue;
> +		}
> +		if (!fdt_valid(&dtbo)) {
> +			/* fdt_valid() clears the pointer upon failure */
> +			dtbo = map_sysmem(addr, 0);
> +			continue;
> +		}
> +
> +		if (fdt_overlay_apply_verbose(working_fdt, dtbo) == 0)
> +			printf("applied\n");
> +	}
> +	unmap_sysmem(dtbo);
> +
> +	fs_closedir(dirs);
> +
> +	return 0;
return CMD_RET_SUCCESS;


Lothar Waßmann