U-Boot: load kernel from JFFS2/UBI image

Guilherme Costa

Hi,

First a little bit of explanation: we use a 128 MB NAND device as our main storage, and we've had many problems related to the use of non NAND aware filesystems, and verified that JFFS2 protects us from most of the possible pitfalls due to NAND 'peculiarities'. Currently, we write our kernel and bootloader images onto raw flash, but we are worried that this might cause use problems in the future due to bit-flips and bad blocks that may appear during the product's lifetime.

During our research, we've run across information that led us o believe that it is possible to put at least the kernel image over a JFFS2 ou UBI system, and load this from NAND to RAM, using U-Boot. I've checked, and our U-Boot version was modified so that all the '.jffs2' commands for the NAND subsystem are equivalent to the common NAND commands (i.e. 'nand read.jffs2' is the same as 'nand read').

Is it possible to do such a thing?

Just to clarify, I do no want to use a JFFS2 image as rootfs, I want to put the kernel itself on a JFFS2 or UBI image, so that i have some guarantee that bit-flips and badblocks will be handled.

We are using U-Boot-2013.01.01-amsdk-06.00.00.

Regards,

Guilherme

over 9 years ago

0 Cvetolin Shulev-XID over 9 years ago

TI__Guru 65405 points

Hi Guilherme,

There is a description about how to flash JFFS2 image to NAND:
processors.wiki.ti.com/.../Put_JFFS2_Image_to_Flash
For more details about u-boot configuration commands refer to AM335x U-boot user's guide at:
processors.wiki.ti.com/.../AM335x_U-Boot_User's_Guide

BR
Tsvetolin Shulev

0 Guilherme Costa over 9 years ago in reply to Cvetolin Shulev-XID

Intellectual 635 points

Cvetolin,

I have no problems flashing the image. What I want is to load the kernel image from a JFFS2 partition. I was able to do so from an UBI partition, but I'm currently having issues when loading a JFFS2 image.

I manage to flash the image and load it to memory, but when I call bootm, I get the following message:

# bootm $kloadaddr
ERROR: can't get kernel image

I believe this to be related to the fact that JFFS2 reads were made equivalent to raw flash reads on my U-Boot version.

0 Guilherme Costa over 9 years ago in reply to Guilherme Costa

Intellectual 635 points

Found out how to do it:

First, add this line to the U-Boot board file:

#CONFIG_JFFS2_NAND

Compile U-Boot. Create a JFFS2 of your uImage, and flash it normally.

On U-Boot console, use this:

U-Boot@am335x# chpart kernel && fsload ${kloadaddr} uImage
U-Boot@am335x# bootm ${kloadaddr}

If you want to use the kernel on top of UBI, simple use enable the ubi commands on U-boot, flash your ubi image with the kernel, attach to it via ubi attach on U-Boot, and use ubi read to load your image to memory. Boot normally with bootm.

Processors

Processors forum

U-Boot: load kernel from JFFS2/UBI image