Run Linux kernel from within a JFFS2 filesystem

Hi all,

this is my first post in this mailing list. I hope I don't start with a FAQ.

On my board I have installed U-Boot and I'm able to run Linux kernel and
rootfs via Flash/Flash (ramdisk/image file) or TFTP/NFS.

Of course, either ramdisk and nfs aren't suitable for my end application (ramdisk losts many RAM space and NFS won't be available).

So I'd like to use a local root filesystem stored in the NOR Flash (a J30 Intel), starting from the small ramdisk I have and adding all software I need.

I could divide my Flash memory in three partitions:
- U-Boot bootloader (with the two sectors for its configuration)
- Linux kernel image
- JFFS2 root filesystem

But I want to go futher and I want to save the linux kernel image file into the root JFFS2 filesystem. So I'll have only two main partitions:
- U-Boot bootloader (...)
- JFFS2 root filesystem (with linuk kernel image file saved inside)

Is U-Boot able to run a kernel image file that is saved into a JFFS2 filesystem stored in the Flash? I think this is what happens on a desktop computer (where the bootloader is Grub and the root filesystem is on a hard-disk and the kernel is a file saved into it).

I think it isn't so simple for U-Boot that is capable of running the application (linux kernel in my case) only at a specified memory address (it doesn't have any knowledge about JFFS2 filesystem, do it?).

Many thanks for your comments and my compliments for the good work!

Giuseppe

Ciao Pes?,

U-Boot can load an image from a jffs2 fs using the fsload command:

fsload DEST_ADDR imagename

Furthermore, you need to properly define the mtdpart and mtdids environment vars or define the opportune #define, like this:

#define MTDIDS_DEFAULT "nor0=phys_mapped_flash"
#define MTDPARTS_DEFAULT "mtdparts=phys_mapped_flash:2M(jffs2),10M(root)ro,2M(u-boot)ro,2M(kernel)ro"

ciao,

luigi

Il giorno sab, 14/06/2008 alle 11.48 +0200, Giuseppe Modugno ha scritto:

Ing. Luigi Mantellini
Industrie Dial Face S.p.A.
Via Canzo, 4
20068 Peschiera Borromeo (MI)
Tel.: +39 02 5167 2813
Fax: +39 02 5167 2459
E-mail: luigi.mantellini at idf-hit.com

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