[RFC][PATCH] spl: Turn spl_board_init() into weak symbol

[Marek Vasut]

On 9/20/22 21:04, Tom Rini wrote:
> On Tue, Sep 20, 2022 at 05:56:50PM +0200, Marek Vasut wrote:
>> On 9/20/22 17:43, Simon Glass wrote:
>>> On Mon, 19 Sept 2022 at 21:52, Marek Vasut <marex at denx.de> wrote:
>>>>
>>>> Make spl_board_init() a weak symbol and get rid of Kconfig symbols
>>>> and ifdeffery guarding this function. Since the spl_board_init() is
>>>> now a weak symbol, boards can either use the default implementation
>>>> which is empty and gets inlined with zero text increase, or override
>>>> the implementation with their own as needed.
>>>>
>>>> Signed-off-by: Marek Vasut <marex at denx.de>
>>>> ---
>>>> Cc: Simon Glass <sjg at chromium.org>
>>>> Cc: Tom Rini <trini at konsulko.com>
>>>> ---
>>>
>>> Reviewed-by: Simon Glass <sjg at chromium.org>
>>>
>>> but please add a nice comment to spl_board_init() indicating what it
>>> is for and when it is called.
>>
>> Actually, I wonder, should we start turning all the other symbols which are
>> now protected by Kconfig symbol (the #ifdef CONFIG_FOO) into weak symbols
>> without any need for Kconfig symbol guard instead as well?
> 
> I'm not sure this is a good idea. An #ifdef in and of itself is not a
> bad thing, and now we add a dummy function on another set of platforms.

The empty dummy function is inlined, so that itself does not increase 
text size.

> What is true is that a lot of SPL_foo symbols should be select'd rather
> than asked because it's not an option. You enable it, it works, you
> disable it, your platform doesn't work. If it's just the #if, we could
> rewrite the line as
> if (CONFIG_IS_ENABLED(BOARD_INIT))
>    spl_board_init();
> 
> as the prototype shouldn't be guarded anyhow.

The third option is what is implemented in this patch -- the board port 
developer implements the weak function override and it always works, 
because it is no longer selectable.

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