[PATCH] arm64: dts: qcom: sm8750: mark the ADSP fastrpc node as non-secure domain

[Qianhui Xu]

On SM8750 the ADSP fastrpc instance used by the sensor core (and by the
other non-secure ADSP users) is the one the firmware exposes as
non-secure; the CDSP fastrpc node already carries
"qcom,non-secure-domain", the ADSP one does not.  With the fastrpc driver
keying the secure/non-secure split off that property, the ADSP only
instantiates /dev/fastrpc-adsp-secure and userspace never gets
/dev/fastrpc-adsp, so libssc/hexagonrpcd cannot attach to the sensor PD
(qrtr service 400) and iio-sensor-proxy reports no sensors at all.

Observed on the Lenovo Legion Tab Y700 Gen4 (TB322FC), which is SM8750
based: without this property /dev/fastrpc-adsp never appears and
iio-sensor-proxy exposes neither accelerometer, ambient light nor
proximity; with it, qrtr shows the "Snapdragon Sensor Core service"
(id 400) and all three sensor types report as available.  The change is
one property on one node, matching what the CDSP node already does.

Tested with `make CHECK_DTBS=y qcom/sm8750-mtp.dtb` (no new warnings; the
single avoid_unnecessary_addr_size warning on dsi@ae96000 is present
before and after).

*** AI-assistance disclosure ***
This patch and its commit message were prepared with the help of an LLM
coding assistant.  The author reviewed the change line by line, ran the
checks quoted above on his own hardware and takes full responsibility
for the content.

Signed-off-by: Qianhui Xu <xiaqinghuan@xxxxxxxxxxxxxxxx>
---
 arch/arm64/boot/dts/qcom/sm8750.dtsi | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/boot/dts/qcom/sm8750.dtsi b/arch/arm64/boot/dts/qcom/sm8750.dtsi
index cf947acc57..9302481b11 100644
--- a/arch/arm64/boot/dts/qcom/sm8750.dtsi
+++ b/arch/arm64/boot/dts/qcom/sm8750.dtsi
@@ -2571,6 +2571,7 @@ fastrpc {
 					compatible = "qcom,fastrpc";
 					qcom,glink-channels = "fastrpcglink-apps-dsp";
 					label = "adsp";
+					qcom,non-secure-domain;
 					memory-region = <&adsp_rpc_remote_heap_mem>;
 					qcom,vmids = <QCOM_SCM_VMID_LPASS
 						      QCOM_SCM_VMID_ADSP_HEAP>;
-- 
2.53.0