[PATCH 1/2] Fix x86 baytrail boot flow.

[Tom Rini]

On Mon, Jul 14, 2025 at 04:02:48PM -0500, Eric Schikschneit wrote:

> It was found that on modern versions of GCC the transition from low level
> assembly into the C function 'fsp_find_header' was no longer valid. A detailed
> step by step analysis with GDB showed that various registers were not being
> initialized properly which would result in the hardware to fail to setup the
> Cache As Ram (CAR) portion. This failure cascades down into later stages of
> initialization because there is no valid stack, or memory for later functions.
> 
> The function 'fsp_find_header' has been rewritten in assembly, which should
> no longer be dependant on a specific version of GCC in order to be usable on
> actual hardware.
> 
> Testing was done using GCC 11.4.0 on Ubuntu 22.04.
> Hardware used for verification: Intel E3845 SoC
> 
> Patch 1 of 2
> 
> Upstream-Status: Pending
> 
> Signed-off-by: Eric Schikschneit <eric.schikschneit at novatechautomation.com>

Sorry for the delayed response here.

[snip]
> diff --git a/common/board_f.c b/common/board_f.c
> index 442b8349d08..3a9ae741d97 100644
> --- a/common/board_f.c
> +++ b/common/board_f.c
> @@ -860,6 +860,7 @@ __weak int clear_bss(void)
>  }
>  
>  static const init_fnc_t init_sequence_f[] = {
> +	arch_fsp_init,          // FSP on platforms like baytrail MUST be done before memory ops
>  	setup_mon_len,
>  #ifdef CONFIG_OF_CONTROL
>  	fdtdec_setup,
> diff --git a/include/init.h b/include/init.h
> index 9a1951d10a0..21d9cea30f6 100644
> --- a/include/init.h
> +++ b/include/init.h
> @@ -68,6 +68,15 @@ int mach_cpu_init(void);
>   */
>  int arch_fsp_init_r(void);
>  
> +/**
> + * arch_fsp_init() - perform firmware support package init
> + *
> + * Where U-Boot relies on binary blobs to handle part of the system init, this
> + * function can be used to set up the blobs. This is used on some Intel
> + * platforms.
> + */
> +int arch_fsp_init(void);
> +
>  int dram_init(void);
>  
>  /**

Doing it this way will break other architectures. Can we just call the
function needed inside of x86 assembly?

-- 
Tom
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