[U-Boot-Users] Question about CFG_ENV_ADDR during RAMBOOT

Ulf Samuelsson ulf at atmel.com
Wed May 30 13:34:19 CEST 2007

Best Regards
Ulf Samuelsson

Atmel Nordic AB
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________________ Sidrubrik f?r svar ________________ ?rende:	Re: [U-Boot-Users] Question about CFG_ENV_ADDR during RAMBOOT F?rfattare: Ladislav Michl <ladis at linux-mips.org> Datum:		2007 maj 30:e 10:54 
On Wed, May 30, 2007 at 08:57:50AM +0200, Wolfgang Denk wrote:
> In message <465CC968.6090801 at atmel.com> you wrote:
> > The dataflash partitioning scheme is static, which is a disadvantage, but
> > If I fix anything, I probably make the partition sizes a configurable item
> > in my buildroot and generate the warning there, if the kernel size is non compliant.
> If you fix anything, then please by making  it  compatible  with  the
> poublic  U-Boot  source  tree,i. e. by using the mtdparts command for
> this purpose.

Here it might be usefull to avoid modifications of certain partition
sizes. For example partition containing environment shouldn't be
modified, because code which read it from U-Boot has size and offset
hardcoded, therefore modifying it will result to bad surprise...

=> We also need to understand if we are talking
about the same thing.
I have this feeling that
mtdparts exist to divide
the rootfs into several
areas while the dataflash
partioning is there purely
for U-boot purposes.

The partion use is:
1) AT91 bootstrap.
2) U-boot environment
3) U-boot image.
4) Kernel image
5) Root FS.

The sum of 1+2+3 is
always 256kB due to
df sector size.
The only programmable value
is the kernel size.

Nothing is ever written to
the dataflash to indicate
partion info and nothing
is passed to Linux 
except rootfs start adress in

The df partion is just for setttins protection
and (in my 1 year+ old patch)
sets a few environment
variables to contain the
start adress of kernel &

Can someone confirm that
mtdparts is the right way
to go?

Best Regards
Ulf Samuelsson

Best Regards
Ulf Samuelsson

Best Regards
Ulf Samuelsson

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