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Date:      Sun, 2 Mar 2014 11:32:01 -0700
From:      Warner Losh <imp@bsdimp.com>
To:        Ian Lepore <ian@FreeBSD.org>
Cc:        Tim Kientzle <tim@kientzle.com>, freebsd-arm <freebsd-arm@FreeBSD.org>
Subject:   Re: A unified imx6 kernel config, old WANDBOARD-* configs going away
Message-ID:  <E8FC82CA-6F23-4CB3-A304-572177444026@bsdimp.com>
In-Reply-To: <1393778472.1149.242.camel@revolution.hippie.lan>
References:  <1393594966.1149.161.camel@revolution.hippie.lan> <F38D0A2F-D2AF-426D-8515-BD111501B2A2@kientzle.com> <CAB3ij4Dd1jq-_v7LVZ75skA3tZVOb=03vJ5JkSCb-7FL8FMrLg@mail.gmail.com> <1393731762.1149.233.camel@revolution.hippie.lan> <9BF14340-2267-473E-B047-E377AA258713@bsdimp.com> <1393778472.1149.242.camel@revolution.hippie.lan>

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On Mar 2, 2014, at 9:41 AM, Ian Lepore <ian@FreeBSD.org> wrote:

> On Sun, 2014-03-02 at 09:30 -0700, Warner Losh wrote:
>> On Mar 1, 2014, at 8:42 PM, Ian Lepore <ian@FreeBSD.org> wrote:
>>=20
>>> On Sat, 2014-03-01 at 18:01 -0700, Tom Everett wrote:
>>>> I'm looking at the crochet code, and I see in freebsd_install_fdt =
that both
>>>> *.dtb and *.dts are supported. However on the source tree it's =
imx6.dtsi.
>>>> What's the difference b/t a dts file and a dtsi file?
>>>=20
>>> A .dtsi file is an include file used by .dts files.  A .dtb is the
>>> binary (compiled) form used by the kernel.
>>>=20
>>> So there are several wandboard-something.dts files, each of which
>>> includes imx6.dtsi where all the common parts live.  For a new imx6
>>> device, a new board-named file similar to one of the wandboard files =
is
>>> necessary, and it would also include imx6.dtsi.
>>=20
>> As would other boards that use the imx6 SoC. They=92d have their own =
.dts
>> file that included the imx6.dsti and customized it for how they are =
wired
>> together.
>>=20
>>> We're pushing hard towards just using the standard dtb files from
>>> vendors, but we've got a bit of work to do before we're there.
>>=20
>> I have some rough changes that allow us to build N different DTBs as =
part
>> of the kernel build, but not glom them into the kernel. Not strictly =
required
>> for this, but helpful.
>>=20
>> I=92m planning on having Atmel use 100% vendor supplied files as =
well.
>> It is a very good goal. There=92s also efforts on the linux side to =
separate out
>> the device-trees from the linux kernel, which is where I grabbed the =
recent
>> /vendor/device-tree stuff from.
>>=20
>> Warner
>=20
> For imx6, the big obstacle to using vendor dtb files is now just the
> device instantiation order.  The stock dts files list devices =
basically
> in order of their memory-mapped register addresses, but we need the
> interrupt controller to be available first regardless of where it's
> mapped, and likewise for a few other critical devices.
>=20
> I need to do another round of experimentation with the
> EARLY_DRIVER_MODULE() stuff and multipass device instantiation.  We =
may
> not be all that far from success.

Taking your patches, I expanded them so that I could list the interrupt =
controller
and such last on my Atmel boards, but still have it attach first=85 I =
want to make
sure that I can get the NAND working just from the FDT file and then I=92d=
 feel
comfortable committing. Interested in peeking at the diffs before I do?

Warner=



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