Re: OE Linux & board-support-package


jchludzinski
 

OK, let me try this:

With other embedded OS's, the hardware specifics that are in the BSP are in the device trees in Linux. I assume the BSP's for OE Linux are rather simple?

On 2022-05-05 04:47, Josef Holzmayr wrote:
Howdy!
Am Do., 5. Mai 2022 um 10:43 Uhr schrieb jchludzinski via
lists.yoctoproject.org
<jchludzinski=vivaldi.net@...>:
OK, let's go with that.
I've watched the "Live Coding with Yocto Project #1: download and first
build" youtube video. Where is the BSP built in this procedure?
The BSP that is implicitly used in that video is the generic QEMU one,
which comes included with poky. Technically speaking, it lives in
https://git.yoctoproject.org/poky/tree/meta/conf/machine and
https://git.yoctoproject.org/poky/tree/meta/recipes-kernel/linux/linux-yocto_5.15.bb
A BSP can be many things, and this one is a rather small one, as
booting into and running linux on QEMU doesn't need patching and all
that, so in that case it comes pretty close to the perfect world that
Michael mentioned.
Greetz,
Josef (who did that video, actually)

On 2022-05-05 03:16, Michael Opdenacker via lists.yoctoproject.org
wrote:
On 5/5/22 08:39, jchludzinski via lists.yoctoproject.org wrote:
A board-support-package (BSP) is software that provides a layer of
abstraction from the physical board specifics for the host embedded OS
(e.g., VXworks).

I believe the device tree files (*.dts, *dtsi) in OE Linux provide the
same function. It allows to OE kernel code to be independent of device
specifics.

The Device Tree files are just descriptions of the hardware. In a
perfect world, you could indeed use the same mainline kernel to support
all possible devices. However, that kernel would be unnecessarily big
for your custom system. You most probably want to customize its
configuration, and may also need custom kernel drivers and patches.
There's also the need for a bootloader compiled for your platform.

That's why we need BSPs :-)

Cheers,
Michael.


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