Re: [PATCH V3 02/10] init.h: Fix the __setup_param() macro for module build

[Arnd Bergmann]

On Wed, Jul 1, 2020 at 11:27 AM Anson Huang <anson.huang@xxxxxxx> wrote:
> > Subject: Re: [PATCH V3 02/10] init.h: Fix the __setup_param() macro for
> > module build
> >
> > On Wed, Jul 1, 2020 at 7:14 AM Anson Huang <anson.huang@xxxxxxx>
> > wrote:
> >
> > I don't understand what your plan is here. Do you mean you will leave that
> > part of the clk driver as built-in?
>
> I meant I will leave the #else block of __setup_param() defined as nothing as below to
> make module build passed.
>
> #define __setup_param(str, unique_id, fn, early)        /* nothing */

No, I think that is  mistake. It will mean that other drivers with the same
bug as the imx-clk driver will appear to build fine, but not work correctly.

A build error is better than silently dropping the command line parsing in
my opinion.

> > This error just means you can't have a __setup_param() call in a loadable
> > module, which we already knew. If you need to do something with the clocks
> > early on, that has to be in built-in code and cannot be in a module. If you don't
> > need that code, then you should just remove it from both the modular version
> > and the built-in version.
> >
> > What is the purpose of that __setup_param() argument parsing in the clock
> > driver?
>
> We need the code for proper uart clock management of earlycon, from the code, it
> is trying to keep console uart clock enabled during kernel boot up.

Why not move this all to a separate file then and only build it when
CONFIG_CLK_IMX=y?
It seems that you don't need the imx_keep_uart_clocks_param() if the
clk driver is
loaded as a module, but then you also don't need the imx_clk_disable_uart()
and imx_register_uart_clocks() functions or the associated variables.

     Arnd