On Wed, Jun 12, 2024 at 01:12:28PM +0200, Tobias Heider wrote:
> The fdtdump command allows dumping arbitrary device tree properties
> and saving them to a variable similar to the smbios command.
>
> This is useful in scripts where further actions such as selecting a
> kernel or loading another device tree depend on the compatible or
> model values of the device tree provided by the firmware.
>
> For now only the root level properties of the dtb are exposed.
>
> Signed-off-by: Tobias Heider <tobias.hei...@canonical.com>
> ---
> grub-core/loader/efi/fdt.c | 51 +++++++++++++++++++++++++++++++++++++-
> 1 file changed, 50 insertions(+), 1 deletion(-)
>
> diff --git a/grub-core/loader/efi/fdt.c b/grub-core/loader/efi/fdt.c
> index 439964b9c..8fa0b3b09 100644
> --- a/grub-core/loader/efi/fdt.c
> +++ b/grub-core/loader/efi/fdt.c
> @@ -1,6 +1,7 @@
> /*
> * GRUB -- GRand Unified Bootloader
> * Copyright (C) 2013-2015 Free Software Foundation, Inc.
> + * Copyright (C) 2024 Canonical, Ltd.
> *
> * GRUB is free software: you can redistribute it and/or modify
> * it under the terms of the GNU General Public License as published by
> @@ -18,15 +19,18 @@
>
> #include <grub/fdt.h>
> #include <grub/mm.h>
> +#include <grub/env.h>
> #include <grub/err.h>
> #include <grub/dl.h>
> #include <grub/command.h>
> +#include <grub/extcmd.h>
> #include <grub/file.h>
> #include <grub/efi/efi.h>
> #include <grub/efi/fdtload.h>
> #include <grub/efi/memory.h>
> #include <grub/cpu/efi/memory.h>
>
> +static void *fw_fdt;
> static void *loaded_fdt;
> static void *fdt;
>
> @@ -36,6 +40,13 @@ static void *fdt;
> sizeof (FDT_ADDR_CELLS_STRING) + \
> sizeof (FDT_SIZE_CELLS_STRING))
>
> +static const struct grub_arg_option options_fdtdump[] = {
> + {"prop", 'p', 0, N_("Get property."), N_("prop"), ARG_TYPE_STRING},
> + {"set", '\0', 0, N_("Store the value in the given variable name."),
> + N_("variable"), ARG_TYPE_STRING},
> + {0, 0, 0, 0, 0, 0}
> +};
> +
> void *
> grub_fdt_load (grub_size_t additional_size)
> {
> @@ -51,7 +62,7 @@ grub_fdt_load (grub_size_t additional_size)
> if (loaded_fdt)
> raw_fdt = loaded_fdt;
> else
> - raw_fdt = grub_efi_get_firmware_fdt();
> + raw_fdt = fw_fdt;
This change seems suspicious for me. Could you explain why it is needed?
> if (raw_fdt)
> size = grub_fdt_get_totalsize (raw_fdt);
> @@ -167,10 +178,47 @@ out:
> return grub_errno;
> }
>
> +static grub_err_t
> +grub_cmd_fdtdump (grub_extcmd_context_t ctxt,
> + int argc __attribute__ ((unused)),
> + char **argv __attribute__ ((unused)))
> +{
> + struct grub_arg_list *state = ctxt->state;
> + const char *value = NULL;
> +
> + if (fw_fdt == NULL)
> + return grub_error (GRUB_ERR_IO,
> + N_("No device tree found"));
> +
> + if (state[0].set)
> + {
> + value = grub_fdt_get_prop(fw_fdt, 0, state[0].arg, NULL);
Missing space before "(".
> + }
Please drop redundant curly braces.
> + if (value == NULL)
> + return grub_error (GRUB_ERR_OUT_OF_RANGE,
> + N_("failed to retrieve the prop field"));
> +
> + if (state[1].set)
> + grub_env_set (state[1].arg, value);
> + else
> + grub_printf ("%s\n", value);
> +
> + return GRUB_ERR_NONE;
> +}
Daniel
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