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Re: JFFS2 on NAND flash




gleixner@xxxxxxx.de said:
> Where can I find this jss2-nand-branch ? I just wan't to have a look
> on it. I  don't know if I have the time and the will do dive into the
> wilderness of  this stuff.

cvs up -r jffs2-nand-branch

> On Friday,  1. February 2002 11:16, David Woodhouse wrote:
> > But it doesn't matter. We want to batch writes and only do one write per
> > page, with page-based ECC. See my ramblings of last week on how we can do
> > this. 

>  I tried something different. I traced on the current jffs2 the
> consecutive I   writes to the pages. I found nowhere a situation where
> a consecutive write to  a page was intermitted by a write to a
> different page. So I assumed that I  can collect the write data (up to
> 512 Byte) in the nand driver and write it  out (with ECC) when a
> access to a different page occurs.

We can do that, but it can't be done in the NAND driver. The JFFS2 code
_must_ be aware of what's happening. The post to which I referred you 
explains the reasons for this.

> If there comes a write request to  a already written page, what
> happened not yet., I copy the block content to  one of some spare
> blocks I reserved at  the end of  the device. Then I erase  the page,
> and write the copied data back. 

You don't need this - the out-of-order write can be guaranteed not to 
happen. 

(NB: Expect high latency/loss on email responses from me for the next 
couple of weeks - I'll be at linux.conf.au.)

--
dwmw2



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