[Yaffs] Re: YAFFS2 boot loader

[Nick Bane]

Rakhi Rathi wrote:
> Hi Nick,
> 
> Do I need to provide any file system support in bootloader if kernel and 
> root fs are going to be stored in seperate partition? Will kernel image 
> able to mount root fs stored by boot loader in root fs partiton?
> 
The bootloader needs to establish yaffs images for use by a loaded linux 
kernel. I typically addin yaffs direct or equivalent functionality so I 
can snoop and/or rewrite files but its not 100% necessary. If you do 
this thogh, MAKE SURE ECC IS THE SAME in bootldr and linux kernel!! This 
is the main cause for grief between bootldr loaded images and kernel usage.

> Why there was need for you to provide JFFS2 / YAFFS2 support in 
> bootloader ? I guess it is required only if you need to read / write 
> file in root partiton otherwise only for loading kernel and root fs in 
> respective partiton, do I need fs support?
See above.

Can this be done on the yaffs list please? It is often helpful for 
others to see the traffic.

Nick
cc yaffs list.
> 
> Thanks,
> Rakhi
> 
> 
> 
> 
> 
> On 10/20/05, *Nick Bane* <nick at cecomputing.co.uk 
> <mailto:nick at cecomputing.co.uk>> wrote:
> 
>     Rakhi Rathi wrote:
>      > Nick, can you please guide me for below listed things.
>      >
>      > Looking forward for positive response from you.....
>      >
>     I was out yesterday till late so I only got your mail this morning.
> 
> 
>      > Thanks,
>      > Rakhi
>      >
>      > On 10/19/05, *Rakhi Rathi* <rakhi5511 at gmail.com
>     <mailto:rakhi5511 at gmail.com>
>      > <mailto:rakhi5511 at gmail.com <mailto:rakhi5511 at gmail.com>>> wrote:
>      >
>      >     Thanks Nick.
>      >
>      >     I want to write mkyaffsimage and mkyaffs utility for creating
>     YAFFS2
>      >     root fs and formatting / programming big/small blocks.  I am
>      >     clueless how can I do that? Could you please give me some
>     guidance
>      >     for the same? I will share the code on YAFFS website too.
>      >
>     It has been a fair while since I looked at mkyaffsimage so I will leave
>     it to others on the list to help there. In principle it is simple, you
>     chunk the world up into pages and oob info and write that to a file. You
>     should probably read the mkyaffsimage source and be at least slightly
>     familiar with it first and then ask some specific questions.
> 
>      >     I want to do this for my own interest and to take first step to
>      >     contribute to open source community.
>      >
>     This is best done on the yaffs list so others can contribute and make
>     suggestions. I know it is on the todo list for several people and it
>     may
>     already have been done. I have cc'd this to the list for comments.
> 
>      >     Also, could please help me with tar of bootldr35 code.
>      >
>     Use wget
>     http://husaberg.toby-churchill.com/releases/development/bootldr/bootldr35
> 
>     I can tar it up if wget is not helpful to you.
> 
>     Nick
> 
>      >     --Rakhi
>      >
>      >
>      >
>      >     On 10/18/05, *Nick Bane* < nick at cecomputing.co.uk
>     <mailto:nick at cecomputing.co.uk>
>      >     <mailto:nick at cecomputing.co.uk
>     <mailto:nick at cecomputing.co.uk>>> wrote:
>      >
>      >         Rakhi Rathi wrote:
>      >>  Thanks Nick.
>      >>
>      >>  I need some more inputs:
>      >>
>      >>  NAND flash are shipped with bad blocks; what will happen if
>      >         you try to
>      >>  load the bootldr using JTAG in block which is bad initially?
>      >>
>      >         Well, we jtag out bootldr into a small bit of NOR and
>     avoid the
>      >         question
>      >         entirely.
>      >         However, reading/writing nand is just a convoluted form of
>      >         reading/writing NOR so in principle it shouldn't be a
>     problem.
>      >
>      >         A bigger problem is booting out of NAND. Have you solved that
>      >         one yet?
>      >         Only the 2k parts do that and one has to hope that the first
>      >         page won't
>      >         become bad with time ...
>      >
>      >
>      >>  Once again thanks for all your help.
>      >>
>      >         Happy to do so.
>      >
>      >         Nick
>      >
> 
> 
> 
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