On Fri, Sep 18, 2009 at 04:21:19PM -0500, Paulraj, Sandeep wrote:
> 
> > 
> > From: Mark A. Greer <[email protected]>
> > 
> > The existing NAND infrastructure allows the default main and
> > mirror bad block tables to be overridden in nand_default_bbt().
> > However, the davinci_nand driver does not support this.  So,
> > add fields to the davinci driver's platform data so platform
> > code can pass in their own bbt's and make the driver honor
> > those overrides.
> > 
> > Signed-off-by: Mark A. Greer <[email protected]>
> > ---
> > This is required by the da830 evm (see following patch) which requires
> > different 'offs' and 'veroffs' values than the default.  This seemed
> > like the solution that fit best with the existing infratructure.  If
> > anyone has a better solution, please speak up.
> > 
> Mark, IIRC this feature was originally added by Andy Lowe in LSP 1.2
> The same was then used in LSP 2.xx.
> 
> In the initial set of patches we were using this again but in the final 
> iterations of the DaVinci NAND driver patch review, we have decided to go 
> with the default patterns from the MTD NAND driver.
> 
> If you look at the Dm355/Dm365 patches for board specific NAND support we do 
> not add this anymore. Since the EMIF on DA830 is similar to DM3xx, in my 
> opinion we should align with DM355 and DM365.

Hi Sandeep.

The issue is that the values for the 'offs' and 'veroffs' are wrong in
the defaults used by nand_base.c:nand_default_bbt().  The da830 evem
won't work with the default values.  So, some way to override the default
needs to be provided.  This patch seemed like the most reasonable way to
override the default since it merely implements driver functionality that
the infrastructure already allows (if not expects).

Its not optimal for the case of the da830 evm because we have to
duplicate a bunch of the data in the platform code--it would be nice to
just override those two values.  However, it still seems like the proper
solution overall.

Or...did I miss your point?

Mark
--

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