[yocto] use yocto toolchain as external toolchain

[Gary Thomas]

On 03/17/2016 12:40 PM, gmane at reliableembeddedsystems.com wrote:
> Hi,
>
> It may sound slightly crazy:) but can I use a toolchain, which was created by Poky as an external toolchain for Poky?
>
> What I am after is something like this:
>
> I create a multiplatfrom v7 compatible Yocto project, which spits out toolchain/rootfs/kernel/various device trees.[1]
>
> Now I need to build for each board a custom u-boot, something like [2][3],...
>
> Obviously [2] and [3] build again the toolchain. Would it be possible to reuse the toolchain built by [1] like an
> external toolchain to save some build time?
>
> Regards,
>
> Robert
>
>
> [1] https://github.com/RobertBerger/meta-mainline/tree/jethro-training-v4.4.x/multi-v7-ml
> [2] https://github.com/RobertBerger/meta-mainline/tree/jethro-training-v4.4.x/beagle-bone-black-multi-v7-ml
> [3] https://github.com/RobertBerger/meta-mainline/tree/jethro-training-v4.4.x/zedboard-multi-v7-ml

No need for an external toolchain.  Simply point builds [2] & [3]
to the sstate-cache from build [1].  This will allow sharing of
much of the build, certainly the toolchain, with the subsequent
builds.  Modify your local.conf to include these lines:
   # Reusable state information
   SSTATE_MIRRORS ?= "\
   file://.* file:///BUILD1/sstate-cache/PATH"
(of course set BUILD1 to the actual path of your build tree)

-- 
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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