arm64: dts: qcom: sdm845: add SLPI FastRPC support

Qualcomm SDM845 SoC features a SLPI DSP which uses FastRPC through
an allocated memory region to load files from the host filesystem
such as sensor configuration files.

Add a FastRPC node at /dev/fastrpc-sdsp and a DMA region, similar to
downstream, to allow userspace to communicate with the SLPI via the
FastRPC interface for initializing the sensors on the SLPI.
Signed-off-by: Dylan Van Assche <me@dylanvanassche.be>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230406173148.28309-4-me@dylanvanassche.be

arch/arm64/boot/dts/qcom/sdm845.dtsi

@@ -13,6 +13,7 @@
 #include <dt-bindings/clock/qcom,rpmh.h>
 #include <dt-bindings/clock/qcom,videocc-sdm845.h>
 #include <dt-bindings/dma/qcom-gpi.h>
+#include <dt-bindings/firmware/qcom,scm.h>
 #include <dt-bindings/gpio/gpio.h>
 #include <dt-bindings/interconnect/qcom,osm-l3.h>
 #include <dt-bindings/interconnect/qcom,sdm845.h>
@@ -876,6 +877,14 @@ mdata_mem: mpss-metadata {
 			size = <0 0x4000>;
 			no-map;
 		};
+
+		fastrpc_mem: fastrpc {
+			compatible = "shared-dma-pool";
+			alloc-ranges = <0x0 0x00000000 0x0 0xffffffff>;
+			alignment = <0x0 0x400000>;
+			size = <0x0 0x1000000>;
+			reusable;
+		};
 	};
 
 	adsp_pas: remoteproc-adsp {
@@ -3361,6 +3370,23 @@ glink-edge {
 				label = "dsps";
 				qcom,remote-pid = <3>;
 				mboxes = <&apss_shared 24>;
+
+				fastrpc {
+					compatible = "qcom,fastrpc";
+					qcom,glink-channels = "fastrpcglink-apps-dsp";
+					label = "sdsp";
+					qcom,non-secure-domain;
+					qcom,vmids = <QCOM_SCM_VMID_HLOS QCOM_SCM_VMID_MSS_MSA
+						      QCOM_SCM_VMID_SSC_Q6 QCOM_SCM_VMID_ADSP_Q6>;
+					memory-region = <&fastrpc_mem>;
+					#address-cells = <1>;
+					#size-cells = <0>;
+
+					compute-cb@0 {
+						compatible = "qcom,fastrpc-compute-cb";
+						reg = <0>;
+					};
+				};
 			};
 		};