[U-Boot] [PATCH 2/3] igep00x0: consolidate defconfigs

[Tom Rini <trini@konsulko.com>]

On Wed, Sep 21, 2016 at 03:46:08PM +0200, Enric Balletbo Serra wrote:
> 2016-09-21 14:51 GMT+02:00 Tom Rini <trini@konsulko.com>:
> > On Wed, Sep 21, 2016 at 01:46:51PM +0200, Enric Balletbo Serra wrote:
> >> Hi,
> >>
> >> 2016-09-21 11:39 GMT+02:00 Ladislav Michl <ladis@linux-mips.org>:
> >> > On Tue, Sep 20, 2016 at 08:26:36PM -0400, Tom Rini wrote:
> >> >> On Wed, Sep 21, 2016 at 01:52:21AM +0200, Ladislav Michl wrote:
> >> >> > On Tue, Sep 20, 2016 at 07:45:14PM -0400, Tom Rini wrote:
> >> > [snip]
> >> >> > > But why do we even need to set MACH_TYPE these days?
> >> >> >
> >> >> > That's only needed for non-device tree kernel boot. These boards run mostly
> >> >> > vendor provided kernels based on TI 2.6.32 or 2.6.37 kernel tree with
> >> >> > daughter boards specific patches on top of it. Enric is concerned not
> >> >> > to break that support, so I'm trying to keep it.
> >> >>
> >> >> OK, if you're still supporting stuff that old then yes, it makes sense.
> >> >> And we can't get this right at run time?
> >> >
> >> > I asked several times, if there's a way to differentiate those boards
> >> > (0020, 0030 and 0032) at runtime, but never get an answer. Of course
> >> > I'd like to see one U-Boot binary to rule them all, but I'm out of clue
> >> > there. Few people added to Cc...
> >>
> >> There is no way to differentiate those boards at runtime, those boards
> >> are completely different platforms that share same processor, like
> >> BeagleBoard or OMAP3 Overos . For me what you're trying to do is join
> >> different platforms with the same processor, so why not join
> >> BeagleBone, Overos, and IGEPs and all other OMAP3 based platforms?
> >
> > Note that the different beagleboard used GPIOs to tell which platform is
> > which :)
> 
> Yes, but if I'm not mistaken you have different GPIOs for different
> hardware revisions of Beagleboard. For IGEPv2 this is also true, you
> have different GPIOs for different hardware revisions of IGEPv2. But
> we're talking about join two completely different boards, i.e join
> IGEPv2 (IGEP0020) with IGEP COM PROTON (IGEP0032) would be similar to
> join Beagleboard with OMAP3 OVERO COM.
> 
> OTOH I think the Ladis work trying to join the IGEP boards is really
> interesting, just want to look deeper :)

Right.  To play the thought exercise out a bit farther, if all of the
detection methods for Beagleboard would _not_ cause an OVERO COM to be
identified as a Beagle, we could move on to trying to see what rev overo
we're on, or just assume it's that if all else fails.  Is anything like
that possible with these IGEP boards?

> >> > Another approach might be to configure U-Boot using FDT and translate
> >> > that information into MACH_TYPE and kernel command line to support
> >> > non-device tree enabled kernels.

And to be clear over on this part, if we can tell at run time (or normal
build time even, without directly passing MACH_TYPE=..) we should set
that then instead of SYS_EXTRA_OPTIONS.

-- 
Tom
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