[U-Boot] Do we really need CONFIG_ARCH_CPU_INIT ?

Simon Glass sjg at chromium.org
Thu Mar 1 22:28:09 CET 2012



On Thu, Mar 1, 2012 at 5:23 AM, Fabio Estevam <festevam at gmail.com> wrote:
> Hi,
> Currently CONFIG_ARCH_CPU_INIT is used to select arch_cpu_init() function.
> arch_cpu_init() does CPU level initialization, so why do we need to
> include CONFIG_ARCH_CPU_INIT in the include/configs/boardXYZ files,
> which are board related files ?
> For example:
> Let's say boards X, Y and Z are based on SoC S:
> 1. If processor S has a arch_cpu_init() defined, then it means that
> X,Y,Z need the code from arch_cpu_init() and then we need to define
> CONFIG_ARCH_CPU_INIT for each of these boards (actually all the boards
> based on this processor would need CONFIG_ARCH_CPU_INIT)
> 2. If not all boards need the code inside arch_cpu_init() for
> processor S, then it means that this code is not really CPU specific
> and then it should be moved to board code.
> I was thinking in doing the following:
> --- a/arch/arm/lib/board.c
> +++ b/arch/arm/lib/board.c
> @@ -224,10 +224,15 @@ void __dram_init_banksize(void)
>  void dram_init_banksize(void)
>        __attribute__((weak, alias("__dram_init_banksize")));
> +int __arch_cpu_init(void)
> +{
> +       return 0;
> +}
> +int arch_cpu_init(void)
> +       __attribute__((weak, alias("__arch_cpu_init")));
> +
>  init_fnc_t *init_sequence[] = {
> -#if defined(CONFIG_ARCH_CPU_INIT)
>        arch_cpu_init,          /* basic arch cpu dependent setup */
> -#endif
>        board_early_init_f,
>  #endif
> ,so that CONFIG_ARCH_CPU_INIT is not needed anymore.
> Before I go further in this route to remove CONFIG_ARCH_CPU_INIT from
> other places, I would like to know if this makes sense.

I consider arch_cpu_init() to be an architecture function, which
should be defined in arch/arm/cpu/ somewhere. For tegra, the function
is in arch/arm/cpu/armv7/tegra2/board.c

If it is a board function then it should be renamed to
board_cpu_init() or similar.

So regarding your proposed change, I feel that the code size impact is
small and it seems reasonable.

However, Graeme's forthcoming initcall mechanism may anyway may your
change obsolete, since then architectures that need it can insert the
call into the initcall sequence, and other archs need not.

Finally, if we accept this change, then my generic board init series
could/should be changed in the same way.


> Thanks,
> Fabio Estevam
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