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

[Sean Anderson]

On 3/23/21 4:35 AM, 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

nit: callback

> to run the same setup.
> 
> Signed-off-by: Green Wan <green.wan at sifive.com>
> ---
>   arch/riscv/cpu/start.S | 5 +++++
>   arch/riscv/lib/spl.c   | 4 ++++
>   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)
> +{
> +}
> +

Can you add some documentation for what the purpose of this function is
and what the limitations are? In particular, this function cannot access
gd.

--Sean

>   __weak int spl_board_init_f(void)
>   {
>   	return 0;
>