[RFC PATCH v2 1/2] arch: riscv: cpu: Add callback to init each core

[Leo Liang <ycliang@andestech.com>]

Hi Green,

On Tue, Mar 23, 2021 at 01:35:38AM -0700, Green Wan wrote:
> Add a callback riscv_hart_early_init() to ./arch/riscv/cpu/start.S to
> allow different riscv hart perform setup code for each hart as early
> as possible. Since all the harts enter the calback, they must be able
> to run the same setup.
> 
> Signed-off-by: Green Wan <green.wan@sifive.com>
> ---
>  arch/riscv/cpu/start.S | 5 +++++
>  arch/riscv/lib/spl.c   | 4 ++++

This patch fails to compile for some defconfigs.
(CI result: https://dev.azure.com/ycliang-tw/u-boot-riscv/_build/results?buildId=15&view=results)

Maybe we should come up with a better place to add this function.

Best regards,
Leo

>  2 files changed, 9 insertions(+)
> 
> diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S
> index 8589509e01..5c7d4da9e2 100644
> --- a/arch/riscv/cpu/start.S
> +++ b/arch/riscv/cpu/start.S
> @@ -117,6 +117,11 @@ call_board_init_f_0:
>  	mv	sp, a0
>  #endif
>  
> +#if CONFIG_IS_ENABLED(RISCV_MMODE)
> +call_riscv_hart_early_init:
> +	jal	riscv_hart_early_init
> +#endif
> +
>  #ifndef CONFIG_XIP
>  	/*
>  	 * Pick hart to initialize global data and run U-Boot. The other harts
> diff --git a/arch/riscv/lib/spl.c b/arch/riscv/lib/spl.c
> index 8baee07bea..e5b1affbfc 100644
> --- a/arch/riscv/lib/spl.c
> +++ b/arch/riscv/lib/spl.c
> @@ -14,6 +14,10 @@
>  
>  DECLARE_GLOBAL_DATA_PTR;
>  
> +__weak void riscv_hart_early_init(void)
> +{
> +}
> +
>  __weak int spl_board_init_f(void)
>  {
>  	return 0;