[U-Boot] [PATCH 7/8] mtd: nand: add driver for diskonchip g4 nand flash

[Scott Wood <scottwood@freescale.com>]

On 04/08/2013 01:25:01 AM, Marek Vasut wrote:
> Dear Mike Dunn,
> 
> > This patch adds a driver for the diskonchip G4 nand flash device.   
> It is
> > based on the driver from the linux kernel.
> >
> > This also includes a separate SPL driver.  A separate SPL driver is  
> used
> > because the device operates in a different mode (reliable mode) when
> > loading a boot image, and also because the storage format of the  
> boot
> > image is different from normal data (pages are stored  
> redundantly).  The
> > SPL driver basically mimics how a typical IPL reads data from the  
> device.
> > The special operating mode and storage format are used to  
> compensate for
> > the fact that the IPL does not contain the BCH ecc decoding  
> algorithm (due
> > to size constraints).  Although the u-boot SPL *could* use ecc, it
> > operates like an IPL for the sake of simplicity and uniformity,  
> since the
> > IPL and SPL share the task of loading the u-boot image. As a side  
> benefit,
> > the SPL driver is very small.
> >
> > Signed-off-by: Mike Dunn <mikedunn@newsguy.com>
> 
> Try #ifdef U_BOOT instead of #if 0, no?

Just remove the code that would be hidden by #if 0.  Besides making the  
U-Boot code easier to read, we *want* to get a conflict marker if we  
try to merge in a new upstream version, and those lines were changed in  
Linux.  This would give us an opportunity to see if similar changes are  
needed to the U-Boot version of the code.

Another option would be to introduce for_each_set_bit in U-Boot.

-Scott