[PATCH 6/7] mach-snapdragon: board interface to enforce fdt

[neil.armstrong at linaro.org]

Hi,

On 07/04/2025 10:19, Jorge Ramirez-Ortiz wrote:
> Some platforms might require the external fdt to boot.

Why ? we may want to build the fdt in, and discard the external fdt for some reasons.

> 
> This change provides a mechanism to the board initializaion code to make
> the requet explicit.
> 
> Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez at oss.qualcomm.com>
> ---
>   arch/arm/mach-snapdragon/board.c | 13 +++++++++++++
>   1 file changed, 13 insertions(+)
> 
> diff --git a/arch/arm/mach-snapdragon/board.c b/arch/arm/mach-snapdragon/board.c
> index 2ef936aab75..1bca9dce20f 100644
> --- a/arch/arm/mach-snapdragon/board.c
> +++ b/arch/arm/mach-snapdragon/board.c
> @@ -150,7 +150,13 @@ static void show_psci_version(void)
>   /* We support booting U-Boot with an internal DT when running as a first-stage bootloader
>    * or for supporting quirky devices where it's easier to leave the downstream DT in place
>    * to improve ABL compatibility. Otherwise, we use the DT provided by ABL.
> + *
> + * Alternatively the board can enforce the external fdt.
>    */
> +bool __weak qcom_board_fdt_external(void)
> +{
> +	return false;
> +}
>   int board_fdt_blob_setup(void **fdtp)
>   {
>   	struct fdt_header *fdt;
> @@ -161,6 +167,12 @@ int board_fdt_blob_setup(void **fdtp)
>   	external_valid = fdt && !fdt_check_header(fdt);
>   	internal_valid = !fdt_check_header(*fdtp);
>   
> +	if (qcom_board_fdt_external() && external_valid) {
> +		debug("Using external FDT\n");
> +		*fdtp = fdt;
> +		goto out;
> +	}
> +
>   	/*
>   	 * There is no point returning an error here, U-Boot can't do anything useful in this situation.
>   	 * Bail out while we can still print a useful error message.
> @@ -178,6 +190,7 @@ int board_fdt_blob_setup(void **fdtp)
>   		*fdtp = fdt;
>   	}
>   
> +out:
>   	/*
>   	 * Parse the /memory node while we're here,
>   	 * this makes it easy to do other things early.