Re: NAND review

[Bart Veer <bartv@ecoscentric.com>]

>>>>> "Andrew" == Andrew Lunn <andrew@lunn.ch> writes:

    Andrew> On Wed, May 20, 2009 at 07:55:58AM -0600, Gary Thomas wrote:
    >> Andrew Lunn wrote:
    >> >> FWIW, this is the approach taken by MTD with the BBT (Bad Block Table).
    >> > 
    >> > Hi Rutger
    >> > 
    >> > You seem to know the MTD code. How does MTD handle partition
    >> > information? Where does it get it from?
    >> 
    >> It can be hard coded, come from the command line, or use the RedBoot
    >> FIS directory.  (any or all of this set)

    Andrew> You could map these into eCos like concepts:

    Andrew> Hard code     -> Hard coded
    Andrew> command line  -> Redboot cfg block parameter?
    Andrew> FIS Directory -> FIS Directory!

    Andrew> I find it interesting that Linux guys consider FIS
    Andrew> directory usable, which is against what Bart was saying.

The approach is usable iff you have NOR flash as well as NAND flash.
    
    Andrew> Putting that point aside, it does show that Linux
    Andrew> considers it necessary to have multiple ways of
    Andrew> configuring the partitions, so maybe eCos also needs
    Andrew> multiple ways of configuring partitions.

To cope with systems which only have NAND flash, I think we must
support hard-coding via configury. Hence that functionality must be
implemented straightaway. It does not preclude adding other ways of
specifying partitions in future, e.g. by storing them in NOR flash, if
we feel that the added flexibility is worth the implementation effort
and the code and data bloat. Obviously typically Linux developers will
be less concerned about the latter than eCos developers.

Bart