iMX233 SPI boot

[tavish]

Hi, I want to use SPI NOR flash boot mode on olinuxino. I
understand how the kernel will be loaded, but is there a
way to use spi flash as the root file system too? As in,
is there a way for linux to detect it automatically as
/dev/sda /dev/sda1 etc?

Is anyone using SPI boot mode?

[jlumme]

Hi,
My ultimate target is this as well. But, so far I've had other things to work on, and I have been lazily waiting for someone (=u-boot) to come up with support for mx23 and SPI boot.
Just recently this has seen a lot of progress from Marek and Otavio. I am now able to probe my flash chip in u-boot as well, thanks to those 2 guys.

But for booting and filesystem, you'll need to look into flash partitioning. You can of course use flash for your root filesystem.
All things seem to work on base of MTD, and the filesystems are different.
Unfortunately, I'm also still learning this stuff, and I can't give any advice how to move from this, as this is now my current task as well..

Everyone seems to shy away from the Freescales SPL bootlets, so I haven't even started looking how to get SPI flash working on that one..

[tavish]

I haven't tried it yet, but I think the file generated from elf2sb tool will
directly be able to boot from SPI flash. It seems that the only way to have
your filesystem on it is to use ramdisk, so that the kernel+ramdisk is loaded
by the imx233 build in ROM code.

[jlumme]

For flash file systems, take a look at for example at SquashFS. It can hold your (read only) rootfs.
Then ie. your /home/ could be CramFS if you need writing to something..
There are several file systems for flash.