2014/1/8 Boris BREZILLON <[email protected]>

> Hello,
>
> This series add the sunxi NFC support with up to 8 NAND chip connected.
> I'm still in the early stages drivers development and some key features are
> missing, but it's usable (I tested it on the cubietruck board).
>

Hello Boris,

Thanks for working on NAND controller support, I was thinking about doing
the non-DMA version of Yuq's driver for mainline testing, but didn't have
time to do it.

First, I want to ask about performance, did you have time to make some
measurements for NAND-flavored file systems like UBIFS/etc. ? Info about
this will be really interesting to know, how it will perform using the
soft_bch and no DMA available.

Second, did you encounter any problems with badblock scan and oob areas
usage? When I was poking around the Yuq's driver I found couple bugs there
that I could not avoid, for example, badblock bug was that on the end of
any NAND chip 4 or 5 blocks were always non-readable after write and
standard badblock detection didn't detect that right, I was forced to
manually shrink my MTD area so it wont use those blocks at the end.

And third, what about the SPL area and possibilities of pure NAND boot?
Yuq's driver had the nand1k things to work this around.

Here's what's missing:
>  - HW ECC support
>  - DMA support
>  - HW randomization support
>  - many more improvements


Any plans on implementing these? Especially, HW ECC/HW random? If I
remember correctly, random was broken in Yuq's driver, even though he tried
to use it exactly like in the allwinner's sources.

And last question, do you plan to implement community 3.4 kernel support?
If your version has no bugs with badblocks/oob it could be used as an
alternative to what we have on 3.4 (the ugly block layer).

Thanks again for working on this subject, hope we will soon see a full NAND
MTD boot on our sunxi devices.

Best Regards,
Dmitriy Beykun

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