[U-Boot] 8/16 bit support for NAND at runtime

[Swarthout Edward L-SWARTHOU]

From: Wolfgang Denk
> 
> Dear Vipin KUMAR,
> 
> In message <4B908BC8.9030306 at st.com> you wrote:
> >
> > > Why would that be needed? Do you really expect to see 
> > > both types of interfaces on the same piece of hardware?
> > 
> > Yes, that's precisely the case with Spear SoC. It has an FSMC 
> > controller embedded in it. FSMC can support 8 as well as 16 bit 
> > devices(off-course with different initializations) for 
> > different banks
> 
> The fact that it _can_ support different bus widths does not 
> mean that anybody would go on and use both at the same time 
> on the same board.
> 
> Do you really have any proof that ther exisits any piece of 
> hardware that has both an 8 bit and a 16 bit NAND flash on it?

Our internal 85xx system test boards (CTS) have a mux for the
local-bus controller chip-select 0 to enable switching between
8-bit and 16-bit NAND devices.

> It seems to be no real problem to me when you have to 
> reconfigure U-Boot and build another image when switching to 
> another piece of hardware that is incompatible enough to use 
> different bus widths.

Yeh, that is what I do now, but it would be nice to have a
single image.

-EdS