[PATCH v2] spl: fit: List DTOs applied by SPL in U-Boot control DT

Simon Glass sjg at chromium.org
Fri Jun 28 09:32:49 CEST 2024


Hi Marek,

On Fri, 28 Jun 2024 at 03:48, Marek Vasut <marex at denx.de> wrote:
>
> Insert /u-boot,spl-applied-dto-<dto-name> = <index> property into the
> U-Boot control DT during SPL DTO application process. This can be used
> by user to inspect which DTOs got applied by the SPL and in which order
> from running U-Boot.
>
> Example:
> ```
> u-boot=> fdt addr $fdtcontroladdr && fdt list /
> Working FDT set to aee9aeb0
> / {
>         u-boot,spl-applied-dto-fdt-dto-imx8mp-dhcom-pdk3-overlay-rev100 = <0x00000005>;
>         u-boot,spl-applied-dto-fdt-dto-imx8mp-dhcom-som-overlay-rev100 = <0x00000004>;
>         u-boot,spl-applied-dto-fdt-dto-imx8mp-dhcom-pdk-overlay-eth2xfast = <0x00000003>;
>         u-boot,spl-applied-dto-fdt-dto-imx8mp-dhcom-som-overlay-eth2xfast = <0x00000002>;
> ...
> ```
>
> Signed-off-by: Marek Vasut <marex at denx.de>
> ---
> Cc: Manoj Sai <abbaraju.manojsai at amarulasolutions.com>
> Cc: Sean Anderson <seanga2 at gmail.com>
> Cc: Simon Glass <sjg at chromium.org>
> Cc: Suniel Mahesh <sunil at amarulasolutions.com>
> Cc: Tom Rini <trini at konsulko.com>
> Cc: u-boot at dh-electronics.com
> Cc: u-boot at lists.denx.de
> ---
> V2: - Expand the DT by one more byte to cater for trailing NUL byte
>     - Update comment related to the expansion of DT
>     - Flip the !ret conditional, which was incorrect and missed
>     - Expand prefix to u-boot,spl-applied-dto-
>     - Document the binding
> ---
>  common/spl/spl_fit.c                | 29 +++++++++++++++++++++++++++--
>  doc/device-tree-bindings/config.txt | 11 +++++++++++
>  2 files changed, 38 insertions(+), 2 deletions(-)

Once this is figured out, can you extend test/image/spl_load_os.c to
test this code?

> diff --git a/common/spl/spl_fit.c b/common/spl/spl_fit.c
> index 988125be008..0a6b5ea8212 100644
> --- a/common/spl/spl_fit.c
> +++ b/common/spl/spl_fit.c
> @@ -363,6 +363,7 @@ static int spl_fit_append_fdt(struct spl_image_info *spl_image,
>  {
>         struct spl_image_info image_info;
>         int node, ret = 0, index = 0;
> +       char dtoname[256];
>
>         /*
>          * Use the address following the image as target address for the
> @@ -448,9 +449,13 @@ static int spl_fit_append_fdt(struct spl_image_info *spl_image,
>                         if (ret < 0)
>                                 break;
>
> -                       /* Make room in FDT for changes from the overlay */
> +                       /*
> +                        * Make room in FDT for changes from the overlay,
> +                        * the overlay name and the trailing NUL byte in
> +                        * that name.
> +                        */
>                         ret = fdt_increase_size(spl_image->fdt_addr,
> -                                               image_info.size);
> +                                               image_info.size + strlen(str) + 1);

Oh and I missed the room for the property, sorry. It needs something like this:

ALIGN(strlen(str) + 1, 4) + 12 + 4

the first bit is the string-table size increase

12 is sizeof(struct fdt_property)
4 is the u32 size

Alos, is there any way to check that there is actually enough space to
increase the size?


>                         if (ret < 0)
>                                 break;
>
> @@ -464,6 +469,26 @@ static int spl_fit_append_fdt(struct spl_image_info *spl_image,
>
>                         debug("%s: DT overlay %s applied\n", __func__,
>                               fit_get_name(ctx->fit, node, NULL));
> +
> +                       /*
> +                        * Insert /u-boot,<dto-name> = <index> property into
> +                        * the U-Boot control DT. This can be used by user
> +                        * to inspect which DTOs got applied by the SPL from
> +                        * a running U-Boot.
> +                        */
> +                       snprintf(dtoname, sizeof(dtoname), "u-boot,spl-applied-dto-%s", str);
> +                       ret = fdt_setprop_u32(spl_image->fdt_addr, 0, dtoname,
> +                                             index);
> +                       if (ret) {
> +                               /*
> +                                * The DTO itself was applied, do not treat the
> +                                * insertion of /u-boot,<dto-name> as an error
> +                                * so the system can possibly boot somehow.
> +                                */
> +                               debug("%s: DT overlay %s name not inserted into / node (%d)\n",
> +                                     __func__,
> +                                     fit_get_name(ctx->fit, node, NULL), ret);
> +                       }
>                 }
>                 free(tmpbuffer);
>                 if (ret)
> diff --git a/doc/device-tree-bindings/config.txt b/doc/device-tree-bindings/config.txt
> index f50c68bbdc3..7aa6d9a72c6 100644
> --- a/doc/device-tree-bindings/config.txt
> +++ b/doc/device-tree-bindings/config.txt
> @@ -95,6 +95,17 @@ rootdisk-offset (int)
>  silent-console (int)
>         If present and non-zero, the console is silenced by default on boot.
>
> +u-boot,spl-applied-dto-* (int)
> +       Emitted by SPL into U-Boot control DT root node in case a DTO from
> +       fitImage was applied on top of U-Boot control DT by the SPL fitImage
> +       loader. The single integer cell indicates in which order was the DTO
> +       applied by the SPL and matches the index of the DTO in the fitImage.
> +       DTOs in fitImage may be skipped using board_spl_fit_append_fdt_skip(),
> +       therefore the integers might not be monotonically incrementing, there
> +       may be gaps. This property can be used to determine which DTOs were
> +       applied by the SPL from running U-Boot by inspecting the U-Boot
> +       control DT.

Should we send a binding with this? I wonder if it would be better to
make the filename a property value rather than including it in the
property name/string table? That way you would not need the
integers...the ordering would be enough.

E.g.

u-boot,spl-applied-dtos = "fdt-dto-imx8mp-dhcom-som-overlay-eth2xfast",
      "fdt-dto-imx8mp-dhcom-pdk-overlay-eth2xfast";

But that might be more annoying to construct as you would probably
need fdt_setprop_placeholder()

> +
>  u-boot,spl-payload-offset (int)
>         If present (and SPL is controlled by the device-tree), this allows
>         to override the CONFIG_SYS_SPI_U_BOOT_OFFS setting using a value
> --
> 2.43.0
>

Regards,
Simon


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