[U-Boot-Users] nand flash controller on 440ep/epx

[Stefan Roese]

Hi Jeff,

On Friday 06 October 2006 19:56, Jeff Mann wrote:
> It appears that the nand flash controller support recently added to
> u-boot for the ppc400ep/epx only supports the use of a single nand chip.

Yes. That's the current status.

> The nand flash controller supports up to four devices using chip selects
> 0-3. I am working on making two devices work right now for my use, but I
> would like to update the flash-controller support. I am open for
> comments on this.
>
> What I think I need to do is add an #config CFG_440_USENANDCONTROLLER
> option and an entry into the nand_chip struct for holding the chip
> select numbers for each chip. Then in addition to configuring an array
> of nand bases {CFG_NAND_BASE} (which would all be the same address
> because it is the address of the nand controller), the chip selects are
> put in a configured array and put into the nand_chip nand struct. The
> read and write functions would then need to be updated to enable the
> right chip select in the nand controller config register too.
>
> Comments? Suggestions? What am I missing?

It seems to me that we are missing a board/cpu specific function to select a 
different NAND chip, when the device is changed via the "nand device x" 
command. This 440EP(x) specific function would then setup the NDFC 
configuration register (NDFC0_CR) to enable the desired NAND chip select. And 
to make it easy I suggest that NAND device 0 represents chips select 0 and so 
on... So no need for additional config options or config arrays.

What do you think?

Best regards,
Stefan