Possibly a FAQ or stupid question

Possibly a FAQ or stupid question

[Ian S. Nelson]

but is there an MTD how-to or anything?

I'm talking about a real idiot's guide, I'm just kind of hacking my way
through a project and I am rapidly approaching the time when I will need
a flash burner program.

Can I just dd to the flash?  Assuming that my AMD flash works with
CFI...

I've also skimmed the archives on JFFS,  any pros and cons vs. an initrd
and burning it in there linearly?  Right now my boot loader will boot
strap a kernel out of flash and then I hacked the kernel to scan for my
initrd in flash and it will decompress it and run, works like a champ
but I need a way to put a new initrd in there now.  Is JFFS compressed?
Can I set aside a few K at the end of flash for my boot loader and then
a few hundred at the beginning for my kernel and use JFFS in the middle?



thanks,
Ian



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Re: Possibly a FAQ or stupid question

[David Woodhouse]

ian.nelson@echostar.com said:
> Can I just dd to the flash?  Assuming that my AMD flash works with CFI... 

No. you have to use the MEMERASE ioctl first. The doc_loadbios program in 
the utils directory of the CVS tree will do this for you. Ignore the name, 
which I should probably change - it's not just for the DiskOnChip.


ian.nelson@echostar.com said:
>  Right now my boot loader will boot strap a kernel out of flash and
> then I hacked the kernel to scan for my initrd in flash and it will
> decompress it and run, works like a champ but I need a way to put a
> new initrd in there now. 

That works. As RAM is cheaper than flash, it makes a lot of sense to do 
that, in the absence of a compressed writable flash filesystem.

> Is JFFS compressed? 

Not yet. Soon. Watch this space.

> Can I set aside a few K at the end of flash for my boot loader and then a
> few hundred at the beginning for my kernel and use JFFS in the middle?

Yep. You can muck about with the partitioning all you like.


--
dwmw2




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Re: Possibly a FAQ or stupid question

[Nicolas Pitre]

On Tue, 5 Dec 2000, David Woodhouse wrote:

>
> ian.nelson@echostar.com said:
> > Can I just dd to the flash?  Assuming that my AMD flash works with CFI...
>
> No. you have to use the MEMERASE ioctl first.

Well...  not if using /dev/mtdblock.

To update my kernel in flash I simply use

	cp zImage /dev/mtdblock1


Nicolas



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