[PATCH 1/1] smbios: add extended Extended BIOS ROM Size

[Ilias Apalodimas]

Hi Heinrich,

On Tue, 23 Jul 2024 at 13:46, Heinrich Schuchardt
<heinrich.schuchardt at canonical.com> wrote:
>
> U-Boot claims to create SMBIOS 3.7 tables. The type 0 table has
> a field Extended BIOS ROM Size since version 3.1.
>
> BIOS ROM sizes of 16 MiB or above must be written to this field.
>
> Add and fill the missing field.
>
> This patch does not cover the case of a ROM >= 8 GiB which cannot
> be configured in U-Boot.
>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> ---
>  include/smbios.h | 1 +
>  lib/smbios.c     | 9 ++++++++-
>  2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/include/smbios.h b/include/smbios.h
> index a4fda9df7bd..00119d7a60c 100644
> --- a/include/smbios.h
> +++ b/include/smbios.h
> @@ -105,6 +105,7 @@ struct __packed smbios_type0 {
>         u8 bios_minor_release;
>         u8 ec_major_release;
>         u8 ec_minor_release;
> +       u16 extended_bios_rom_size;
>         char eos[SMBIOS_STRUCT_EOS_BYTES];
>  };
>
> diff --git a/lib/smbios.c b/lib/smbios.c
> index 4126466e34a..e2a2f873a94 100644
> --- a/lib/smbios.c
> +++ b/lib/smbios.c
> @@ -348,7 +348,14 @@ static int smbios_write_type0(ulong *current, int handle,
>  #endif
>         t->bios_release_date = smbios_add_prop(ctx, NULL, U_BOOT_DMI_DATE);
>  #ifdef CONFIG_ROM_SIZE
> -       t->bios_rom_size = (CONFIG_ROM_SIZE / 65536) - 1;
> +       if (CONFIG_ROM_SIZE < 0x1000000) {

nit, but can we use SZ_16M instead? Then the comment below goes away

> +               /* CONFIG_ROM_SIZE < 16 MiB */
> +               t->bios_rom_size = (CONFIG_ROM_SIZE / 65536) - 1;
> +       } else {
> +               /* CONFIG_ROM_SIZE < 8 GiB */
> +               t->bios_rom_size = 0xff;

If the size is above 1gb we should also change bits 15:14. I guess
being above 1GB will never happen, but can we add a comment?

Thanks
/IIlias
> +               t->extended_bios_rom_size = CONFIG_ROM_SIZE >> 20;
> +       }
>  #endif
>         t->bios_characteristics = BIOS_CHARACTERISTICS_PCI_SUPPORTED |
>                                   BIOS_CHARACTERISTICS_SELECTABLE_BOOT |
> --
> 2.45.2
>