[U-Boot] [PATCH v2 08/16] tegra: nand: fix read_byte required for proper onfi detection

[Scott Wood]

On Tue, 2015-07-28 at 04:05 +0200, Marcel Ziswiler wrote:
> On 27 July 2015 22:00:15 CEST, Scott Wood <scottwood at freescale.com> wrote:
> > On Tue, 2015-07-21 at 00:35 +0200, Marcel Ziswiler wrote:
> > > From: Marcel Ziswiler <marcel.ziswiler at toradex.com>
> > > 
> > > Fix PIO read_byte() implementation not only used for the legacy READ
> > ID
> > > but also the PARAM command now required for proper ONFI detection.
> > > 
> > > This fix is inspired by Lucas Stach's Linux Tegra NAND driver of
> > late.
> > 
> > Could you explain a bit more how this fixes issues with READ PARAM?
> 
> I vaguely remember that those commands are special on 16-bit bus NAND (e.g. 
> always return 8-bit data regardless) and later Linux MTD fixed/changed the 
> way this is handled which in turn broke once U-Boot pulled that in. Which 
> as explained in my commit message this fixes by doing what Lucas does in 
> Linux (not mainline yet but getting there soon I hope).

The more detail about this you can put in the changelog (describing what it 
is that Lucas does and how it helps), the better.

> > > While at it also disable subpage writes.
> > 
> > Why are these two changes combined?
> 
> Well just because it's a one line fix but if required I can split that in a 
> separate patch as well.

I think it should be separate, at least so it gets a separate changelog 
explaining why.

-Scott