dt-bindings: PCI: Add ASPEED PCIe RC support

ASPEED AST2600 provides one PCIe RC with 5GT/s and AST2700 provides three
PCIe RC for two 16GT/s and one 5GT/s. All of these RCs have just one Root
Port to connect to PCIe device. And also have Mem, I/O access, legacy
interrupt and MSI.

Signed-off-by: Jacky Chou <jacky_chou@aspeedtech.com>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20251216-upstream_pcie_rc-v7-2-4aeb0f53c4ce@aspeedtech.com

Author: aspeedJacky

Documentation/devicetree/bindings/pci/aspeed,ast2600-pcie.yaml

@@ -0,0 +1,182 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pci/aspeed,ast2600-pcie.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ASPEED PCIe Root Complex Controller
+
+maintainers:
+  - Jacky Chou <jacky_chou@aspeedtech.com>
+
+description:
+  The ASPEED PCIe Root Complex controller provides PCI Express Root Complex
+  functionality for ASPEED SoCs, such as the AST2600 and AST2700.
+  This controller enables connectivity to PCIe endpoint devices, supporting
+  memory and I/O windows, MSI and INTx interrupts, and integration with
+  the SoC's clock, reset, and pinctrl subsystems. On AST2600, the PCIe Root
+  Port device number is always 8.
+
+properties:
+  compatible:
+    enum:
+      - aspeed,ast2600-pcie
+      - aspeed,ast2700-pcie
+
+  reg:
+    maxItems: 1
+
+  ranges:
+    minItems: 2
+    maxItems: 2
+
+  interrupts:
+    maxItems: 1
+    description: INTx and MSI interrupt
+
+  resets:
+    items:
+      - description: PCIe controller reset
+
+  reset-names:
+    items:
+      - const: h2x
+
+  aspeed,ahbc:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Phandle to the ASPEED AHB Controller (AHBC) syscon node.
+      This reference is used by the PCIe controller to access
+      system-level configuration registers related to the AHB bus.
+      To enable AHB access for the PCIe controller.
+
+  aspeed,pciecfg:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Phandle to the ASPEED PCIe configuration syscon node.
+      This reference allows the PCIe controller to access
+      SoC-specific PCIe configuration registers. There are the others
+      functions such PCIe RC and PCIe EP will use this common register
+      to configure the SoC interfaces.
+
+  interrupt-controller: true
+
+patternProperties:
+  "^pcie@[0-9a-f]+,0$":
+    type: object
+    $ref: /schemas/pci/pci-pci-bridge.yaml#
+
+    properties:
+      reg:
+        maxItems: 1
+
+      resets:
+        items:
+          - description: PERST# signal
+
+      reset-names:
+        items:
+          - const: perst
+
+      clocks:
+        maxItems: 1
+
+      phys:
+        maxItems: 1
+
+    required:
+      - resets
+      - reset-names
+      - clocks
+      - phys
+      - ranges
+
+    unevaluatedProperties: false
+
+allOf:
+  - $ref: /schemas/pci/pci-host-bridge.yaml#
+  - $ref: /schemas/interrupt-controller/msi-controller.yaml#
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: aspeed,ast2600-pcie
+    then:
+      required:
+        - aspeed,ahbc
+    else:
+      properties:
+        aspeed,ahbc: false
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: aspeed,ast2700-pcie
+    then:
+      required:
+        - aspeed,pciecfg
+    else:
+      properties:
+        aspeed,pciecfg: false
+
+required:
+  - reg
+  - interrupts
+  - bus-range
+  - ranges
+  - resets
+  - reset-names
+  - msi-controller
+  - interrupt-controller
+  - interrupt-map-mask
+  - interrupt-map
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/clock/ast2600-clock.h>
+
+    pcie0: pcie@1e770000 {
+      compatible = "aspeed,ast2600-pcie";
+      device_type = "pci";
+      reg = <0x1e770000 0x100>;
+      #address-cells = <3>;
+      #size-cells = <2>;
+      interrupts = <GIC_SPI 168 IRQ_TYPE_LEVEL_HIGH>;
+      bus-range = <0x00 0xff>;
+
+      ranges = <0x01000000 0x0 0x00018000 0x00018000 0x0 0x00008000
+                0x02000000 0x0 0x60000000 0x60000000 0x0 0x20000000>;
+
+      resets = <&syscon ASPEED_RESET_H2X>;
+      reset-names = "h2x";
+
+      #interrupt-cells = <1>;
+      msi-controller;
+
+      aspeed,ahbc = <&ahbc>;
+
+      interrupt-controller;
+      interrupt-map-mask = <0 0 0 7>;
+      interrupt-map = <0 0 0 1 &pcie0 0>,
+                      <0 0 0 2 &pcie0 1>,
+                      <0 0 0 3 &pcie0 2>,
+                      <0 0 0 4 &pcie0 3>;
+
+      pcie@8,0 {
+        compatible = "pciclass,0604";
+        reg = <0x00004000 0 0 0 0>;
+        #address-cells = <3>;
+        #size-cells = <2>;
+        device_type = "pci";
+        resets = <&syscon ASPEED_RESET_PCIE_RC_O>;
+        reset-names = "perst";
+        clocks = <&syscon ASPEED_CLK_GATE_BCLK>;
+        pinctrl-names = "default";
+        pinctrl-0 = <&pinctrl_pcierc1_default>;
+        phys = <&pcie_phy1>;
+        ranges;
+      };
+    };