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

[Vipin KUMAR <vipin.kumar@st.com>]

On 3/21/2010 10:20 PM, Wolfgang Denk wrote:
> Dear Vipin KUMAR,
> 
> In message <4B908BC8.9030306@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 eexisits any piece of hardware
> that has both an 8 bit and a 16 bit NAND flash on it?
> 

I agree with the above point. This is a board configuration but I am
tempted to make a single image because it can be done in the software

>>> Otherwise you just have misconfigured your board, and fixing the
>>> configuration should all that is needed to make the code work.  Or am
>>> I missing something?
>>
>> I could make the code work with both 8 as well as 16 bit devices. The
>> only thing is that I have to make a few changes and rebuild the uboot
>> for a particular interface
> 
> 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.
> 

Again, the board config way is also fine with me. I was just thinking
that it can be done at runtime also which obviates the need of a different
configurations for a NAND device change

> Best regards,
> 
> Wolfgang Denk
>