[Arm-netbook] 2.7.4 preproduction sample, 1.7 MD, Questions

Luke Kenneth Casson Leighton lkcl at lkcl.net
Sun Jul 19 21:43:59 BST 2020

On Sun, Jul 19, 2020 at 9:35 PM Paul Boddie <paul at boddie.org.uk> wrote:
> On Sunday, 19 July 2020 22:19:37 CEST Luke Kenneth Casson Leighton wrote:
> > On Sun, Jul 19, 2020 at 9:02 PM Pablo Rath <pablo at parobalth.org> wrote:
> > > Ok. But what did you use as defconfig in configs/ (U-Boot mainline)?
> >
> > it was 4 years ago: your guess is as good as mine, unless i happened
> > to put it in the wiki somewhere.
> Currently, I am updating this page:
> http://rhombus-tech.net/allwinner_a10/Building_Linux/
> On which I noted that the boot page...
> http://rhombus-tech.net/allwinner/a20/boot/
> ...provides a special configuration (eoma68-a20-4.7-config) that would
> presumably get copied into the configs directory as some kind of defconfig.
> However, it is probably superseded by the sunxi_defconfig file now, for the
> most part.

sounds about right.

> It looks like the device tree (sun7i-a20-eoma68-a20.dts) is very similar to
> that from the Cubietruck 2.

that sounds about right.  possibly the original cubieboard.

> Were the differences documented and are there any
> schematics to provide any necessary insight when updating the device tree?

there's PDFs somewhere... http://hands.com/~lkcl/eoma/
such as this: http://hands.com/~lkcl/eoma/DS113-V2.7-2017-02-17.pdf

the thing is that it is critically important that the dts file *do
not* include the peripherals associated with the "Boards"
(Micro-Desktop, 15in laptop).  the peripheral sets *MUST* go into a
"dynamic include" file that is detected at boot time and "inserted"
into the live device-tree.

this functionality - dynamic runtime "insertion" of device-tree
fragments - was an idea *in development* back in.... 2013  we have had
to wait several years for this functionality to make its way into both
u-boot and the linux kernel.


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