Booting mx25 based device from SD and NOR

Roberto Nibali rnibali at
Thu May 24 09:18:13 EDT 2012

Hi Eric

On Thu, May 24, 2012 at 2:58 PM, Eric Bénard <eric at> wrote:

> Hi Roberto,
> Le Thu, 24 May 2012 14:49:36 +0200,
> Roberto Nibali <rnibali at> a écrit :
> > I haven't found a combination of root/rootfstype yet that permits me to
> > boot from barebox either from NFS, TFTP, MMC/SD or NOR yet. No matter
> what
> > I try, the kernel spits back at me.
> >
> well NAND boot + nand rootfs works fine here (cpuimx25) and I assume
> NAND boot + sd rootfs would work as sd is properly detected during boot.
> Yep, I believe it's more a question of me setting the parameters correctly
upon boot. But without a proper low level init (which I don't have because
I do not really understand all the details of the low level code), there
are other factors which could inhibit the proper boot, as you mention below.

> > Also I have the problem that my NOR is only detected when using barebox
> as
> > a second stage boot loader from uboot. If booting from SD into barebox,
> the
> > NOR is not detected. I have added the following changes to figure out
> > what's going on:
> >
> > .../...
> > What's going on here?
> >
> bad iomux and/or bad WEIM configuration

I support WEIM configuration is done in the low level part, isn't it? Where
would I find an appropriate example? I have been reading all the fsl
board's low_level codes, but have a hard time figuring out how to apply it
to my board.

With regard to the IOMUX, I was under the impression that it does not
matter much, since after low level code run, the execution path is:

        device_initcall() --> add_cfi_flash_device()
        console_initcall() --> mxc_iomux_v3_setup_multiple_pads()

So CFI/NOR detection happens before IOMUX setup, at least that's what I
have gathered for my board copying from various other examples in barebox.
What would the correct code execution path be from the architectural point
of view?

Best regards
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