Date: Sun, 02 Mar 2014 09:41:12 -0700 From: Ian Lepore <ian@FreeBSD.org> To: Warner Losh <imp@bsdimp.com> 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: <1393778472.1149.242.camel@revolution.hippie.lan> In-Reply-To: <9BF14340-2267-473E-B047-E377AA258713@bsdimp.com> 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>
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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 th= at 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=A2d have their own .d= ts > file that included the imx6.dsti and customized it for how they are wir= ed > 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 pa= rt > of the kernel build, but not glom them into the kernel. Not strictly re= quired > for this, but helpful. >=20 > I=A2m planning on having Atmel use 100% vendor supplied files as well. > It is a very good goal. There=A2s also efforts on the linux side to sep= arate out > the device-trees from the linux kernel, which is where I grabbed the re= cent > /vendor/device-tree stuff from. >=20 > Warner 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. 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. -- Ian
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