[U-Boot] [PATCH v3] Add support for MINI2440 (s3c2440). Documentation about the product can be found on: http://www.friendlyarm.net/products/mini2440

[Ilya Averyanov]

2012/4/20 Marek Vasut <marex at denx.de>

> Dear Ilya Averyanov,
>
> > 2012/4/20 Marek Vasut <marex at denx.de>
> >
> > > Dear Ilya Averyanov,
> > >
> > > [...]
> > >
> > > > > > > > > > .word 0x32
> > > > > > > > > > +    .word 0x30
> > > > > > > > > > +    .word 0x30
> > > > > > > > >
> > > > > > > > > What this undocumented stuff?
> > > > > > > >
> > > > > > > > SoC specific, I pasted it from smdk2410, it's for initialize
> > > > > > > > the
> > > > >
> > > > > DRAM.
> > > > >
> > > > > > > Can't you init DRAM in some more fitting place? Also document
> > > > > > > this?
> > > > > >
> > > > > > I don't know, this part is a bit difficult for me, but I'm going
> to
> > >
> > > try
> > >
> > > > > > to document it with the help of the SoC documentation.
> > > > > >
> > > > > > For the place, should I move it to mini2440.c in arch_cpu_init()
> or
> > > > > > board_early_init_f() ? I don't really know the difference.
> > > > >
> > > > > dram_init() maybe ?
> > > >
> > > > You propose to initialize the SDRAM controller in dram_init ()?
> > >
> > > Well yes, ain't it more fitting ?
> > >
> > > Best regards,
> > > Marek Vasut
> >
> > No. We have to two reasons why this is not the case.
> > 1) Open u-boot/arch/arm/cpu/arm920t/start.S:328
> > cpu_init_crit
> > ......
> > line 346
> >     /*
> >      * before relocating, we have to setup RAM timing
> >      * because memory timing is board-dependend, you will
> >      * find a lowlevel_init.S in your board directory.
> >      */
>
> Well don't setup run in lowlevel_init.S then ?
>
> > 2) NAND controller must be initialized before C code run.
>
> Why?
>
> Best regards,
> Marek Vasut
>
mmm...
Because we need a stack.
The stack is in RAM.