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

Mike Dunn
2013-04-09T15:36:41Z

On 04/08/2013 05:59 PM, Scott Wood wrote:
> 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.

OK.

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

This was my first inclination, but it looked like a lot of work across multiple
architectures, so I let it go.

Thanks,
Mike