TODO List

TODO List

[Trevor Woolven]

Hi Everyone,

Dave Woodhouse and I had a meeting yesterday and we came up with the
following list of things that need doing to/fixing in the MTD code:

1	Write Support
	a	ECC
	b	Bad block handling (static)
	c	Bad block detection and handling (dynamic)
	d	Timing constraints
	e	Asynchronous writes

2	FTL fix

3	Support for NOR flash/PCMCIA

4	Support utilities
	a	Formatting
	b	Bad sector/block detection
	c	Consistency checking

5	Documentation
	a	Architectural description
	b	User Guide and API listing
	c	...

6	DOC Millenium support

7	Fix the character device memory copy to/from user space

8	JFFS/FFS2 support

9	GRUB
	a	Filesystem support (NFTL, JFFS etc)
	b	MTD support

10	Execute-in-place

We attempted to prioritize them as we saw fit with the following two
goals: 
	a)	submission to the main-stream linux kernel (2.4/2.5)
	b)	production of a fully GPL alternative to what M-Systems offer

Since Dave's still officially on holiday I agreed to post this to the
list. We're after your opinions and suggestions regarding the TODO list
and the two immediate goals for this work. We're also after volunteers
to take on various parts of the development. Please feel free to comment
upon the above.

Thanks,

Trevor.

--
Zentropix Inc - a Lineo company

Tel: +44 (0)1273 234 647	 Fax: +44 (0)1273 704 482

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RE: TODO List

[Jamey Hicks]

> 2	FTL fix

What's wrong with FTL?
What's the state of it wrt licensing M-Systems patents?  Can it be used for
systems with onboard flash?

-Jamey


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Re: TODO List

[Trevor Woolven]

Jamey Hicks wrote:
> 
> > 2     FTL fix
> 
> What's wrong with FTL?
> What's the state of it wrt licensing M-Systems patents?  Can it be used for
> systems with onboard flash?
> 
> -Jamey
DW thinks FTL needs to be Big-Endian on BE machines and Little-Endian on
LE machines and never the twain shall meet, which seems strange. He
posted this observation to the list a while back and would like further
information on it before proceeding with a fix.

I'm not sure about the licensing issue, is this another subject for the
TODO list?

Best regards

Trevor.
-- 
Zentropix Inc - a Lineo company

Tel: +44 (0)1273 234 647	 Fax: +44 (0)1273 704 482

Visit http://www.zentropix.com/ for Real Time Linux Tools
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Re: TODO List

[David Woodhouse]

jamey@crl.dec.com said:
>  What's wrong with FTL?

Technically, there are two main problems.

Firstly, it's broken - it works for a while and then seems to corrupt the
 FTL. I can't see how I did that in porting David Hinds' code to use the MTD
flash access routines - so it could be an SMP issue (I'm testing on SMP) or it
could be because I'm testing on the RAM device, which calls the 'erase done'
callback directly from within the erase routine..

Secondly, it makes no attempt to handle byte-swapping - so if you run it on a 
BE machine, then your FTL is all BE, which doesn't conform to the spec, and 
obviously won't be portable to LE machines. We need to pepper it with 
cpu_to_le16() and le16_to_cpu() all over the place.

> What's the state of it wrt licensing M-Systems patents? 

M-Systems have a patent which covers FTL, but they've given a licence to use 
it on all PCMCIA devices. They have not granted a licence to use it with 
non-PCMCIA devices.

>  Can it be used for systems with onboard flash? 

I assume that's not actually the question you meant to ask.

Can it be used? Yes - although you'd do better to use JFFS.
May it be used? Only if you live in the Free World.



--
dwmw2




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