AW: NAND ECC errors

[markus.stockhausen at gmx.de]

> Anyone good ideas what to do first from here?
>
> Probably depends. Blanking the NAND chip and reformatting it will 
> resolve the errors from and upstream point of view. That's obviously not 
> really going to be something you want to do if you expect to swap back 
> and forth between the stock firmware and an upstream kernel.
>
> You'll probably want to convince the mtd code to allow the on-die ECC to 
> be disabled and find whatever software BCH settings are needed that work 
> with the stock firmware. Then we could maybe look at using the ECC 
> controller to accelerate that.

Good direction. So assumption is: 
- vendor wrote BCH6 into OOB 
- This design is also active in his firmware (with Realtek ECC engine)
- now we read data with upstream kernel and on-die ECC
- Each read produces an on-die ECC error
- As soon as we write new data on-die ECC will be created 

But where is the ECC knob in between spi-realtek-nand, mtd and ubi?