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

Scott Wood
2013-04-09T00:59:01Z

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