[U-Boot] NOR NAND Interference question

[Scott Wood <scottwood@freescale.com>]

On 01/04/2013 05:47:06 PM, Andrei wrote:
> Hi,
>  Recently I am start getting strange problem
> with u-boot-2011.09. MPC8313ERDB like
> configuration ( main change - I am using
> different NAND flash - 256MBib - need change
> page size)

Please always try with the latest U-Boot when you have a problem -- or  
even when you don't have a problem. :-)

> If I am access NAND flash before nor
> u-boot not always read NOR correctly.
> 
> >mtdparts
> 
> device nor0 <phys_mapped_flash>, # parts = 3
>  #: name                size            offset          mask_flags
>  0: u-boot              0x000e0000      0x00000000      0
>  1: env                 0x00020000      0x000e0000      0
>  2: jffs2               0x01f00000      0x00100000      0
> 
> device nand0 <e2800000.flash>, # parts = 1
>  #: name                size            offset          mask_flags
>  0: ubifs               0x10000000      0x00000000      0
> 
> If I do:
> ubi part ubifs;ubifsmount iptec_nand
> 
> and read something from NAND before I read NOR

How much time passes between the NAND access and the NOR access?  If  
it's all part of a script, maybe the NAND access isn't quite finished  
when the command returns.

We used to have problems on Linux with NAND and NOR interfering, though  
I wouldn't think that it would be possible in U-Boot even with the old  
broken code because of its single-tasking nature.

One thing you might want to try is applying Linux commit  
476459a6cf46d20ec73d9b211f3894ced5f9871e ("mtd: eLBC NAND: use  
recommended command sequences") to U-Boot.

> I found most stable configuration:
> mount NAND, read NAND,
> chaprt nor0,2
> boot
> 
> and most unstable
> chaprt nor0,2
> mount NAND, read NAND,
> boot

I don't see "chaprt" in the U-Boot sources.  Where did you get U-Boot  
from?

I thought your problem was doing NAND before NOR, not the other way  
around.

> And I did increase malloc size to 1M.( ubifs does not like 128K).

MPC8313ERDB has always had a malloc size of 512K -- where did 128K come  
from?

> There is no option for stack size  - it is PPC,
> so it should grow down as needed.

It grows down within the area that has been designated for the stack.   
This area is not very large.  Do you have any reason to believe you're  
seeing stack issues?

-Scott