[PATCH v2 1/5] dt-bindings: pci: Add Sophgo SG2042 PCIe host

[Chen Wang]

From: Chen Wang <unicorn_wang at outlook.com>

Add binding for Sophgo SG2042 PCIe host controller.

Signed-off-by: Chen Wang <unicorn_wang at outlook.com>
---
 .../bindings/pci/sophgo,sg2042-pcie-host.yaml | 141 ++++++++++++++++++
 1 file changed, 141 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pci/sophgo,sg2042-pcie-host.yaml

diff --git a/Documentation/devicetree/bindings/pci/sophgo,sg2042-pcie-host.yaml b/Documentation/devicetree/bindings/pci/sophgo,sg2042-pcie-host.yaml
new file mode 100644
index 000000000000..aec31ec97092
--- /dev/null
+++ b/Documentation/devicetree/bindings/pci/sophgo,sg2042-pcie-host.yaml
@@ -0,0 +1,141 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pci/sophgo,sg2042-pcie-host.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sophgo SG2042 PCIe Host (Cadence PCIe Wrapper)
+
+description:
+  Sophgo SG2042 PCIe host controller is based on the Cadence PCIe core.
+
+maintainers:
+  - Chen Wang <unicorn_wang at outlook.com>
+
+properties:
+  compatible:
+    const: sophgo,sg2042-pcie-host
+
+  reg:
+    maxItems: 2
+
+  reg-names:
+    items:
+      - const: reg
+      - const: cfg
+
+  vendor-id:
+    const: 0x1f1c
+
+  device-id:
+    const: 0x2042
+
+  msi:
+    type: object
+    $ref: /schemas/interrupt-controller/msi-controller.yaml#
+    unevaluatedProperties: false
+
+    properties:
+      compatible:
+        items:
+          - const: sophgo,sg2042-pcie-msi
+
+      interrupts:
+        maxItems: 1
+
+      interrupt-names:
+        const: msi
+
+  msi-parent: true
+
+  sophgo,pcie-port:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      SG2042 uses Cadence IP, every IP is composed of 2 cores(called link0
+      & link1 as Cadence's term). "sophgo,pcie-port" is used to identify which
+      core/link the pcie host controller node corresponds to.
+
+      The Cadence IP has two modes of operation, selected by a strap pin.
+
+      In the single-link mode, the Cadence PCIe core instance associated
+      with Link0 is connected to all the lanes and the Cadence PCIe core
+      instance associated with Link1 is inactive.
+
+      In the dual-link mode, the Cadence PCIe core instance associated
+      with Link0 is connected to the lower half of the lanes and the
+      Cadence PCIe core instance associated with Link1 is connected to
+      the upper half of the lanes.
+
+      SG2042 contains 2 Cadence IPs and configures the Cores as below:
+
+                     +-- Core(Link0) <---> pcie_rc0   +-----------------+
+                     |                                |                 |
+      Cadence IP 1 --+                                | cdns_pcie0_ctrl |
+                     |                                |                 |
+                     +-- Core(Link1) <---> disabled   +-----------------+
+
+                     +-- Core(Link0) <---> pcie_rc1   +-----------------+
+                     |                                |                 |
+      Cadence IP 2 --+                                | cdns_pcie1_ctrl |
+                     |                                |                 |
+                     +-- Core(Link1) <---> pcie_rc2   +-----------------+
+
+      pcie_rcX is pcie node ("sophgo,sg2042-pcie-host") defined in DTS.
+      cdns_pcie0_ctrl is syscon node ("sophgo,sg2042-pcie-ctrl") defined in DTS
+
+      cdns_pcieX_ctrl contains some registers shared by pcie_rcX, even two
+      RC(Link)s may share different bits of the same register. For example,
+      cdns_pcie1_ctrl contains registers shared by link0 & link1 for Cadence IP 2.
+
+      "sophgo,pcie-port" is defined to flag which core(link) the rc maps to, with
+      this we can know what registers(bits) we should use.
+
+  sophgo,syscon-pcie-ctrl:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Phandle to the PCIe System Controller DT node. It's required to
+      access some MSI operation registers shared by PCIe RCs.
+
+allOf:
+  - $ref: cdns-pcie-host.yaml#
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - vendor-id
+  - device-id
+  - sophgo,syscon-pcie-ctrl
+  - sophgo,pcie-port
+
+additionalProperties: true
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    pcie at 62000000 {
+      compatible = "sophgo,sg2042-pcie-host";
+      device_type = "pci";
+      reg = <0x62000000  0x00800000>,
+            <0x48000000  0x00001000>;
+      reg-names = "reg", "cfg";
+      #address-cells = <3>;
+      #size-cells = <2>;
+      ranges = <0x81000000 0 0x00000000 0xde000000 0 0x00010000>,
+               <0x82000000 0 0xd0400000 0xd0400000 0 0x0d000000>;
+      bus-range = <0x80 0xbf>;
+      vendor-id = <0x1f1c>;
+      device-id = <0x2042>;
+      cdns,no-bar-match-nbits = <48>;
+      sophgo,pcie-port = <0>;
+      sophgo,syscon-pcie-ctrl = <&cdns_pcie1_ctrl>;
+      msi-parent = <&msi_pcie>;
+      msi_pcie: msi {
+        compatible = "sophgo,sg2042-pcie-msi";
+        msi-controller;
+        interrupt-parent = <&intc>;
+        interrupts = <123 IRQ_TYPE_LEVEL_HIGH>;
+        interrupt-names = "msi";
+      };
+    };
-- 
2.34.1