[oe] how to create a new layer

[Philip Balister]

On 05/21/2014 04:05 PM, Richard Cagley wrote:
> On Wed, May 21, 2014 at 12:26 PM, Robert Calhoun
> <rcalhoun at shotspotter.com> wrote:
>>
>>
>> On 5/21/14 2:26 PM, "Richard Cagley" <rcagley at gmail.com> wrote:
>>
>>> I'd like to create a new machine that inherits from an existing
>>> machine. What's the easiest way to do this?
>>>
>>> Looking through the yocto documentation I see "yocot-bsp create" but I
>>> don't seem to have that executable. Do I need to use this or is there
>>> an alternate method?
>>
>> The script is in: poky/scripts/yocto-bsp
>>
>> You don't really need it. The script creates a directory structure for you
>> and generates some files, but there is nothing magical about it; you can
>> create those manually using the meta-yocto-bsp layer as an example.
>> Machine configs are in poky/meta-yocto-bsp/conf/machine.
>>
>> To make bitbake use your new layer:
>> a) add your layer to poky/build/conf/bblayers.conf so that that bitbake
>> knows what directories to search
>> b) set your machine name in poky/build/conf/local.conf
>>
>> I would recommend putting your own layer into git (or scm of choice).
>> Switching branches on poky will make the build fail if your .bbappends no
>> longer match up with recipes in oe-core, so it's helpful to be able to
>> switch between e.g. "a version of my layer that works with branch daisy"
>> and "a version of my layer that works with branch master".
>>
>> Rob Calhoun
>>
> oh, I don't think I'm using poky so I guess that's the reason I didn't
> find yocto-bsp
> 
> I'm using oe-core/meta-xilinx and for testing I've created a new test
> layer "meta-me" so my bblayers looks like this
> 
> BBLAYERS ?= " \
>   /home/rcagley/oe-zed-gcc-min/openembedded-core/meta \
>   /home/rcagley/oe-zed-gcc-min/meta-xilinx \
>   /home/rcagley/oe-zed-gcc-min/meta-oe/meta-oe \
>   /home/rcagley/oe-zed-gcc-min/meta-me \
>   "
> 
> In my local.conf I have
> MACHINE ??= "zedboard-zynq7"
> 
> My current main goal is to make my build consume a .bbappend file I
> have in meta-me/recipes-kernel/linux.
> 
> 1.) What is the minimum set of files I need to do this? I'd guess at
> least meta-me/conf/local.conf. Anything else?

You do not need a per layer local.conf

> 2.) Do I need to change the machine name? If so, how to I inherit
> zedboard-zynq7?

Make a conf/machine/me.conf.

You can use one of the zynq machines as a starting point.

You'll need a conf/layer.conf also.

Philip

> 
> The yocto manuals talk to creating a new layer, but I'm less clear on
> how to basically inherit everything.
> 
> BTW, thanks for the tip about git/matching branches. That's a good idea.
>