Describe the binding for firmware-configured instances of the Synopsys
Designware PCIe controller in RC mode, that are almost but not quite
ECAM compliant.
Cc: Rob Herring <robh@xxxxxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
Documentation/devicetree/bindings/pci/designware-pcie-ecam.txt | 42 ++++++++++++++++++++
1 file changed, 42 insertions(+)
diff --git a/Documentation/devicetree/bindings/pci/designware-pcie-ecam.txt b/Documentation/devicetree/bindings/pci/designware-pcie-ecam.txt
new file mode 100644
index 000000000000..29bad1337c87
--- /dev/null
+++ b/Documentation/devicetree/bindings/pci/designware-pcie-ecam.txt
@@ -0,0 +1,42 @@
+* Synopsys Designware PCIe root complex in ECAM mode
+
+In some cases, firmware may already have configured the Synopsys Designware
+PCIe controller in RC mode with static ATU window mappings that cover all
+config, MMIO and I/O spaces in a [mostly] ECAM compatible fashion.
+In this case, there is no need for the OS to perform any low level setup
+of clocks, PHYs or device registers, nor is there any reason for the driver
+to reconfigure ATU windows for config and/or IO space accesses at runtime.
+
+In cases where the IP was synthesized with a minimum ATU window size of
+64 KB, it cannot be supported by the generic ECAM driver, because it
+requires special config space accessors that filter accesses to device #1
+and beyond on the first bus.
+
+Required properties:
+- compatible: "marvell,armada8k-pcie-ecam" or
+ "socionext,synquacer-pcie-ecam" or
+ "snps,dw-pcie-ecam" (must be preceded by a more specific match)
+
+Please refer to the binding document of "pci-host-ecam-generic" in the
+file host-generic-pci.txt for a description of the remaining required
+and optional properties.
+
+Example:
+
+ pcie1: pcie@7f000000 {
+ compatible = "socionext,synquacer-pcie-ecam", "snps,dw-pcie-ecam";
+ device_type = "pci";
+ reg = <0x0 0x7f000000 0x0 0xf00000>;
+ bus-range = <0x0 0xe>;
+ #address-cells = <3>;
+ #size-cells = <2>;
+ ranges = <0x1000000 0x00 0x00010000 0x00 0x7ff00000 0x0 0x00010000>,
+ <0x2000000 0x00 0x70000000 0x00 0x70000000 0x0 0x0f000000>,
+ <0x3000000 0x3f 0x00000000 0x3f 0x00000000 0x1 0x00000000>;
+
+ #interrupt-cells = <0x1>;
+ interrupt-map-mask = <0x0 0x0 0x0 0x0>;
+ interrupt-map = <0x0 0x0 0x0 0x0 &gic 0x0 0x0 0x0 182 0x4>;
+ msi-map = <0x0 &its 0x0 0x10000>;
+ dma-coherent;
+ };
--
2.11.0
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