[U-Boot] Do we really need CONFIG_ARCH_CPU_INIT ?

[Christian Riesch]

Hi,

On Thu, Mar 1, 2012 at 9:48 PM, Albert ARIBAUD
<albert.u.boot at aribaud.net> wrote:
> Le 01/03/2012 14:23, Fabio Estevam a écrit :
>
>> 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.
>
>
> ... or some of these boards have a kind of preloader that does CPU level
> inits before U-Boot is loaded, but other have not.

Exactly. da850 based systems have several options to to lowlevel
configuration, either in the AIS (a script interpreted by the ROM
bootloader of the SoC), or by UBL (a user bootloader from Texas
Instruments that does low level init and then loads u-boot) or by
u-boot itself in arch_cpu_init(). Which way is used is board specific,
but if the initialization is done by u-boot, the code is the same for
all boards, it does not make sense to duplicate it.

Boards that use the low level initialization in u-boot define
CONFIG_ARCH_CPU_INIT, boards that rely on AIS or UBL do not define it.

So if CONFIG_ARCH_CPU_INIT is removed, what should be done with da850
based boards?

Christian