[Yaffs] YAFFS2 boot loader

[Rakhi Rathi]

Thanks Charles.

I would like to explain my problem in detail!

I want to use YAFFS2 as flash file system.

I need to store two stage boot loader in NAND. Stage - 1 bootloader stored
(First 4k code can be loaded in Internal RAM ) in block 0, which is
responsible to copy the stage -2 boot loader from other portion of the NAND
to SDRAM and pass control to it for execution. Stage - 2 boot loader is
responsible initializing peripherals and booting up kernel image.

Design Approach - 1 : Have separate partitions for Stage -2 boot loader ,
kernel image and root file system.

Advantage:- kernel images can be loaded using TFTP / FTP support available
in boot loader.

Disadvantage:- If only 'n' number of blocks are allocated for loading kernel
image and all the allocated blocks goes bad after some program / erase
cycles then you can not load kernel image again!

Design Approach 2: have two partition boot and root. Bootloader will mount
root partition and boot the kernel image!

Advantage:- Kernel image program / erase is not restricted to some partition
space!

Disadvantage: - As root file system can be mounted only as read only from
boot loader. I can not reload kernel image from boot loader. I need to flash
entire root file system again!

What efforts are required to mount root file system as read / write from
boot loader?

How mkyaffs utility works? How it marks bad block when first time it is used
to flash the images
on NAND flash?

--Rakhi

On 9/29/05, Charles Manning <manningc2 at actrix.gen.nz> wrote:
>
> On Thursday 29 September 2005 01:11, Rakhi Rathi wrote:
> > Hi All,
> >
> > Is YAFFS boot loader code available under cvs directory 'direct'
> supports
> > mounting of root file system in read / write mode?
> This only allows read mode.
>
> It is intended to support reading a boot image file, that is all.
>
> -- Charles
>
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