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<div class="moz-cite-prefix">On 8/10/2021 13:39, Joel Sherrill
wrote:<br>
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<div dir="ltr" class="gmail_attr">On Tue, Aug 10, 2021, 9:58
AM Gedare Bloom <<a href="mailto:gedare@rtems.org" moz-do-not-send="true">gedare@rtems.org</a>> wrote:<br>
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<div dir="ltr" class="gmail_attr">On Tue, Aug 10, 2021
at 5:34 AM Kuan-Hsun Chen <<a href="mailto:c0066c@gmail.com" target="_blank" rel="noreferrer" moz-do-not-send="true">c0066c@gmail.com</a>>
wrote:<br>
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<div style="font-family:verdana,sans-serif">Hi
Benson,</div>
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<div style="font-family:verdana,sans-serif">Regarding
Discord for RTEMS, here you go: <a href="https://discord.gg/TKhmGt8p" target="_blank" rel="noreferrer" moz-do-not-send="true">https://discord.gg/TKhmGt8p</a>.</div>
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<div style="font-family:verdana,sans-serif">Best,<br>
Kuan-Hsun</div>
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<div dir="ltr" class="gmail_attr">On Tue, Aug 10,
2021 at 1:21 PM Mathew Benson <<a href="mailto:mbenson@windhoverlabs.com" target="_blank" rel="noreferrer" moz-do-not-send="true">mbenson@windhoverlabs.com</a>>
wrote:<br>
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<div>Is there a Slack or Discord channel to
discuss RTEMS? I don't want to flood
everybody's inbox with emails.</div>
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<div>As well, for this kind of development work
(porting RTEMS), you can bring your discussions and
questions over to <a href="mailto:devel@rtems.org" target="_blank" rel="noreferrer" moz-do-not-send="true">devel@rtems.org</a>.</div>
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<div>I want to port RTEMS to the Xilinx Zynq
Ultrascale+ R5. I've taken the RTEMS
training, but that was a couple years ago.
I think I'll be fine once I can just get
through the build system and can focus on
just code, but the build system seems very
foreign to me. There still seems to be
either fragments of an old build system or
just files that don't seem to serve any
purpose. It would appear that
"/spec/build/bsps/arm/xilinx-zynqmp" is
where my build set definition begins, but
then what is
"/bsps/arm/xilinx-zynqmp/config" for?<br>
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<div>We haven't quite divorced ourselves from the
older autotools build system, but new BSPs/ports
(including the aarch64) are not using the old build
system at all. </div>
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<div>The arm/xilinx-zynqmp is a BSP for only the
32-bit arm support of the Zynq Ultrascale+ MPSOC
specifically tested/used on the Ultra96. It was
contributed by Dornerworks. I guess this is a little
confusing, because now we also have
bsps/aarch64/xilinx-zynqmp, which provides the
64-bit support. At some point, we should be able to
deprecate/drop the arm/xilinx-zynqmp with the
ability to configure the aarch64/xilinx-zynqmp to
only run in aarch32 mode.</div>
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<div dir="auto">Probably worth starting a thread to ask Kinsey
about that. I think the user was trying something like that at
one point.</div>
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The arm/xilinx-zynqmp BSP is in a weird spot. It works, but requires
either booting from JTAG or a seldom-used configuration of FSBL. It
could also theoretically be booted from a very thin shim layer of
AArch64 code on top of a more typical AArch64 FSBL. Realistically,
it needs better documentation. Running ARMv7 RTEMS code on the A53
CPUs is definitely possible and I have worked with someone who has
tested on it some, but still belongs in bsps/arm because it is
fundamentally not AArch64 even though it has an identical peripheral
set and runs on the same silicon. In my opinion, the only reason to
run in this mode is to reuse existing and tested binaries with only
minor/trivial porting required. If you're compiling the entire OS
from scratch and reverifying, it is much better to run AArch64 with
the ILP32 ABI since it gives you the same smaller-memory advantages
as ARMv7 as well as the advantages of AArch64 underneath the hood.<br>
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<div dir="auto">I also think the BSP dornerworks contributed can
run under Xen. So that would have to be accounted for <br>
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As best I can tell, that is a completely separate BSP just for
running under Xen on ARM and unrelated to any Zynq BSPs.<br>
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<p>Kinsey<br>
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