arm64: dts: qcom: sm8450: Use GIC-ITS for PCIe0 and PCIe1

Both PCIe0 and PCIe1 controllers are capable of signalling the MSIs
received from endpoint devices to the CPU using GIC-ITS MSI controller.
Add support for it.

Currently, BDF (0:0.0) and BDF (1:0.0) are enabled and with the
msi-map-mask of 0xff00, all the 32 devices under these two busses can
share the same Device ID.

The GIC-ITS MSI implementation provides an advantage over internal MSI
implementation using Locality-specific Peripheral Interrupts (LPI) that
would allow MSIs to be targeted for each CPU core.

It should be noted that the MSIs for BDF (1:0.0) only works with Device
ID of 0x5980 and 0x5a00. Hence, the IDs are swapped.
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Tested-by: Konrad Dybcio <konrad.dybcio@linaro.org> # Xperia 1 IV (WCN6855)
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230102105821.28243-4-manivannan.sadhasivam@linaro.org

arch/arm64/boot/dts/qcom/sm8450.dtsi

@@ -1742,9 +1742,13 @@ pcie0: pci@1c00000 {
 			ranges = <0x01000000 0x0 0x60200000 0 0x60200000 0x0 0x100000>,
 				 <0x02000000 0x0 0x60300000 0 0x60300000 0x0 0x3d00000>;
 
-			interrupts = <GIC_SPI 141 IRQ_TYPE_LEVEL_HIGH>;
-			interrupt-names = "msi";
-			#interrupt-cells = <1>;
+			/*
+			 * MSIs for BDF (1:0.0) only works with Device ID 0x5980.
+			 * Hence, the IDs are swapped.
+			 */
+			msi-map = <0x0 &gic_its 0x5981 0x1>,
+				  <0x100 &gic_its 0x5980 0x1>;
+			msi-map-mask = <0xff00>;
 			interrupt-map-mask = <0 0 0 0x7>;
 			interrupt-map = <0 0 0 1 &intc 0 0 0 149 IRQ_TYPE_LEVEL_HIGH>, /* int_a */
 					<0 0 0 2 &intc 0 0 0 150 IRQ_TYPE_LEVEL_HIGH>, /* int_b */
@@ -1851,9 +1855,13 @@ pcie1: pci@1c08000 {
 			ranges = <0x01000000 0x0 0x40200000 0 0x40200000 0x0 0x100000>,
 				 <0x02000000 0x0 0x40300000 0 0x40300000 0x0 0x1fd00000>;
 
-			interrupts = <GIC_SPI 307 IRQ_TYPE_LEVEL_HIGH>;
-			interrupt-names = "msi";
-			#interrupt-cells = <1>;
+			/*
+			 * MSIs for BDF (1:0.0) only works with Device ID 0x5a00.
+			 * Hence, the IDs are swapped.
+			 */
+			msi-map = <0x0 &gic_its 0x5a01 0x1>,
+				  <0x100 &gic_its 0x5a00 0x1>;
+			msi-map-mask = <0xff00>;
 			interrupt-map-mask = <0 0 0 0x7>;
 			interrupt-map = <0 0 0 1 &intc 0 0 0 434 IRQ_TYPE_LEVEL_HIGH>, /* int_a */
 					<0 0 0 2 &intc 0 0 0 435 IRQ_TYPE_LEVEL_HIGH>, /* int_b */