W dniu 28.03.2024 o 16:43, Peter Maydell pisze:
On Tue, 26 Mar 2024 at 09:58, Marcin Juszkiewicz
<marcin.juszkiew...@linaro.org> wrote:
Hardware of sbsa-ref board is nowadays defined by both BSA and SBSA
specifications. Then BBR defines firmware interface.
Added note about DeviceTree data passed from QEMU to firmware. It is
very minimal and provides only data we use in firmware.
Added NUMA information to list of things reported by DeviceTree.
Signed-off-by: Marcin Juszkiewicz <marcin.juszkiew...@linaro.org>
---
docs/system/arm/sbsa.rst | 37 ++++++++++++++++++++++++++++---------
1 file changed, 28 insertions(+), 9 deletions(-)
diff --git a/docs/system/arm/sbsa.rst b/docs/system/arm/sbsa.rst
index bca61608ff..d4d1f2efe3 100644
--- a/docs/system/arm/sbsa.rst
+++ b/docs/system/arm/sbsa.rst
+Note
+''''
+
+QEMU provides us with minimal information about hardware platform using
s/us/the guest EL3 firmware/ (or whatever other term you want to
use to describe the guest software that reads the dt).
Thanks, fixed.
+minimalistic devicetree. This is not a Linux devicetree. It is not even a
+firmware devicetree.
+
+It is information passed from QEMU to describe the information a hardware
+platform would have other mechanisms to discover at runtime, that are affected
+by the QEMU command line.
Might want to say also
Guest EL3 firmware does not pass this devicetree on to later
components of the software stack.
?
This is a matter of what firmware stack QEMU user will run. TF-A (our
current "guest EL3 firmware") passed devicetree to later components of
the software stack. We just stopped using it in EDK2. But if someone
would like to run U-Boot or other firmware then both SMC and DT will
wait for them.
+
+Ultimately this devicetree will be replaced by IPC calls to an emulated SCP.
+And when we do that, we won't then have to rewrite Normal world firmware to
+cope.
I would drop the last sentence here, and use "may" instead of "will".
Done.
+
DeviceTree information
''''''''''''''''''''''
-The devicetree provided by the board model to the firmware is not intended
-to be a complete compliant DT. It currently reports:
+The devicetree reports:
- CPUs
- memory
- platform version
- GIC addresses
+ - NUMA node id for CPUs and memory
Otherwise looks good to me, and the updates to the spec URLs
are particularly helpful. As a docs change I'd be happy
to take it into 9.0 (at least before rc2) if some other
sbsa-ref-knowledgeable person wants to either review or ack it.
(But it's also OK if it misses 9.0 and goes into 9.1.)
OK.
