ECC byte 4 and 5 not equal to what have just been writen

[Thomas Gleixner]

On Tuesday 20 April 2004 12:37, Shen Aaron-r62966 wrote:
> > -----Original Message-----
> > On Tuesday 20 April 2004 11:40, Shen Aaron-r62966 wrote:
> > So you are debugging your bootloader code and not kernel code ?
> > Did you copy the code from 2.4.18 ? If yes, use code from
> > actual MTD CVS.
> > If no, which version of MTD code did you use to copy from ?
>
> Yes, right. I'm debugging my bootloader code. I'm using the 2.4.18 kernel,
> so I didn't use the code from actual MTD CVS. There're many differences for
> the actual CVS, for example, the nand_ecc.h and other head files are added
> into linux/mtd/. I don't think it's a good choice to use the mtd code from
> actual CVS if it's not a known problem. And I'm not sure whether such
> update will do harm to my system. I think the code in 2.4.18 should work
> for it. But I need to find out what's the problem.

Hmm, known problem is a nice phrase. The code in 2.4.18 was not used in 
production AFAIK. 

All you need is pageprogramming which is quite straight forward:
Write the start programm command
Write out 512 byte data + 16 byte oob
Write the programm command 
Wait for ready

> > The page write function is the right place to look
>
> Yes, The only step before I re-read the oob data is the page write
> function. But I have added more debugging information into this function
> and still can't find the causing. Is it possible that the Nand Flash
> Controller does some operation after a page has been writen?

Is this the builtin controller on iMX2 ?
I dont know, what this does, as I have no datasheet. The product brief tells 
something about automatic ECC...
Maybe you have to check this first

-- 
Thomas
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