Configure RAM size on iMX53 board

[Sascha Hauer]

On Tue, Nov 08, 2016 at 09:51:36PM +0100, Jose Luis Zabalza wrote:
> > So you have 512MiB on each chip select, so I assume that on the 512MiB
> > board variants CS1 is not equipped.
> 
> Yes, it is.
> 
> >In that case you can in lowlevel.c
> > test if you find SDRAM on CS1 and if not, disable the chip select
> > completely in the SDRAM controller.
> 
> OK. But how ? I enable CS0 and CS1 on DCD table. Is there any way to
> tell barebox not to use CS1 ?
> 
> > I am not sure how you can detect if there's SDRAM on CS1. I've seen
> > situations in which the board just hangs if you access non existent RAM
> > areas.
> 
> I have tried it, but I have not be able to implement a code for
> autodetect. If the code write or read a value on a position without
> physical  chip, the microcontroller hangs. ????
> 
> But it's not a problem. A solution is configure both CS and MMU. If
> bootloader don't access to high positions, there is not problem. After
> I set a environment variable with memory size and the mem kernel
> parameter (or ATAG) does the rest.

You said that both board variants work with the same U-Boot binary, how
does it work there? Is there some detection mechanism or is it only some
environment variable that you have to set manually?

Sascha

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