[PATCH 3/3] fdt: introduce apply_all command

[Simon Glass]

Hi Andre,

On Tue, 5 Jul 2022 at 11:14, Andre Przywara <andre.przywara at arm.com> 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 apply-all" 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 at arm.com>
> ---
>  cmd/fdt.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 88 insertions(+), 1 deletion(-)

This looks OK, but can you please add a test (see test/dm/acpi.c for
example) and doc/usage/cmd file?

Also, apply_all is a bit annoying as we try to allow command
completion and abbreviations to work. Given that the args are
different I don't think a -d (for dir) flag makes sense.

Perhaps 'fdt fsapply' ?

Regards,
Simon


>
> diff --git a/cmd/fdt.c b/cmd/fdt.c
> index d6878c96f1..dc80e13c3d 100644
> --- a/cmd/fdt.c
> +++ b/cmd/fdt.c
> @@ -12,12 +12,14 @@
>  #include <env.h>
>  #include <image.h>
>  #include <linux/ctype.h>
> +#include <linux/sizes.h>
>  #include <linux/types.h>
>  #include <asm/global_data.h>
>  #include <linux/libfdt.h>
>  #include <fdt_support.h>
>  #include <mapmem.h>
>  #include <asm/io.h>
> +#include <fs.h>
>
>  #define MAX_LEVEL      32              /* how deeply nested we will go */
>  #define SCRATCHPAD     1024            /* bytes of scratchpad memory */
> @@ -107,6 +109,81 @@ 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;
> +}
> +#endif
> +
>  /*
>   * Flattened Device Tree command, see the help for parameter definitions.
>   */
> @@ -703,7 +780,7 @@ static int do_fdt(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
>         }
>  #ifdef CONFIG_OF_LIBFDT_OVERLAY
>         /* apply an overlay */
> -       else if (strncmp(argv[1], "ap", 2) == 0) {
> +       else if (strcmp(argv[1], "apply") == 0) {
>                 unsigned long addr;
>                 struct fdt_header *blob;
>                 int ret;
> @@ -723,6 +800,15 @@ static int do_fdt(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
>                 ret = fdt_overlay_apply_verbose(working_fdt, blob);
>                 if (ret)
>                         return CMD_RET_FAILURE;
> +       /* apply all .dtbo files from a directory */
> +       } else if (strncmp(argv[1], "apply", 5) == 0) {
> +               if (argc != 5)
> +                       return CMD_RET_USAGE;
> +
> +               if (!working_fdt)
> +                       return CMD_RET_FAILURE;
> +
> +               return apply_all_overlays(argv[2], argv[3], argv[4]);
>         }
>  #endif
>         /* resize the fdt */
> @@ -1080,6 +1166,7 @@ static char fdt_help_text[] =
>         "addr [-c] [-q] <addr> [<size>]  - Set the [control] fdt location to <addr>\n"
>  #ifdef CONFIG_OF_LIBFDT_OVERLAY
>         "fdt apply <addr>                    - Apply overlay to the DT\n"
> +       "fdt apply_all <ifname> <dev:part> <dir> - Apply all overlays in directory\n"
>  #endif
>  #ifdef CONFIG_OF_BOARD_SETUP
>         "fdt boardsetup                      - Do board-specific set up\n"
> --
> 2.25.1
>