[PATCH v2 01/23] dt-bindings: display: msm: Add Qualcomm DCP

[Jayant Shekhar]

DCP platforms place the display pipeline under firmware control, so Linux
cannot discover display resources through direct register access. The DRM
driver therefore needs device-tree descriptions of the Qualcomm transport
wrapper, display topology, IOMMU contexts, and panel connections.

Add bindings for the Qualcomm DCP transport wrapper and VirtIO display
subsystem. Document the IPCC power-notify resources, transport and
framebuffer IOMMU contexts, firmware-visible IOVA range, INTF graph, and
DSI panel connections. The wrapper creates a standard VirtIO-MMIO child
after the IPCC power-notify sequence has completed.

Assisted-by: LLM
Signed-off-by: Jayant Shekhar <jayant.shekhar@xxxxxxxxxxxxxxxx>
---
 .../bindings/display/msm/qcom,dcp-dsi.yaml         |  79 ++++++++++++
 .../devicetree/bindings/display/msm/qcom,dcp.yaml  | 123 +++++++++++++++++++
 .../bindings/virtio/qcom,dcp-virtio.yaml           | 132 +++++++++++++++++++++
 3 files changed, 334 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/msm/qcom,dcp-dsi.yaml b/Documentation/devicetree/bindings/display/msm/qcom,dcp-dsi.yaml
new file mode 100644
index 000000000000..9a0acaf00bb3
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/msm/qcom,dcp-dsi.yaml
@@ -0,0 +1,79 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/msm/qcom,dcp-dsi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm DCP DSI host
+
+maintainers:
+  - Jayant Shekhar <jayant.shekhar@xxxxxxxxxxxxxxxx>
+
+description: |
+  A MIPI DSI host exposed by the Qualcomm DCP VirtIO device (see
+  qcom,dcp.yaml). It follows the generic DSI controller binding, with panel
+  devices described as child nodes. The DCP INTF graph endpoint connects
+  directly to the panel; the DSI host node is not a graph endpoint. The host
+  node uses the dsi@N naming convention, and its reg property identifies the
+  DSI host index.
+
+allOf:
+  - $ref: /schemas/display/dsi-controller.yaml#
+
+properties:
+  reg:
+    maxItems: 1
+    description: DSI host index matching the DCP output port.
+
+required:
+  - reg
+  - "#address-cells"
+  - "#size-cells"
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    dcp-subsystem {
+        compatible = "virtio,device34";
+        iommus = <&apps_smmu 0x400 0x2>;
+
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        ports {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            port@0 {
+                reg = <0>;
+                dcp_intf0_out: endpoint {
+                    remote-endpoint = <&panel_dcp_in>;
+                };
+            };
+        };
+
+        dsi@0 {
+            reg = <0>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            panel@0 {
+                compatible = "novatek,nt37801";
+                reg = <0>;
+
+                vddio-supply = <&vreg_l12b_1p8>;
+                vci-supply = <&vreg_l13b_3p0>;
+                vdd-supply = <&display_panel_vdd>;
+                reset-gpios = <&tlmm 210 GPIO_ACTIVE_LOW>;
+
+                port {
+                    panel_dcp_in: endpoint {
+                        remote-endpoint = <&dcp_intf0_out>;
+                    };
+                };
+            };
+        };
+    };
diff --git a/Documentation/devicetree/bindings/display/msm/qcom,dcp.yaml b/Documentation/devicetree/bindings/display/msm/qcom,dcp.yaml
new file mode 100644
index 000000000000..96f6c2a17e9e
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/msm/qcom,dcp.yaml
@@ -0,0 +1,123 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/msm/qcom,dcp.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm Display Co-Processor (DCP)
+
+maintainers:
+  - Jayant Shekhar <jayant.shekhar@xxxxxxxxxxxxxxxx>
+
+description: |
+  The Display Co-Processor (DCP) is a firmware-owned display subsystem.
+  Linux communicates with DCP over HFI through VirtIO and does not access
+  display hardware registers directly.
+
+  This node describes the externally connected display graph between DCP
+  INTF outputs and attached DSI panels. It is assigned to the VirtIO device
+  by the Qualcomm transport driver and is not independently enumerated.
+  Firmware capabilities and internal resources, including pipes, mixers,
+  CRTCs, and clocks, are discovered at runtime.
+
+allOf:
+  - $ref: /schemas/virtio/virtio-device.yaml#
+
+properties:
+  compatible:
+    const: virtio,device34
+
+  iommus:
+    maxItems: 1
+    description:
+      SMMU context used by DCP firmware to access GEM framebuffers. This
+      is separate from the HFI transport context specified by the
+      iommus property on the parent DCP transport node.
+      The child context is used for framebuffer DMA performed by DCP
+      firmware, while the parent context is used for VirtIO transport and HFI
+      queue buffers. These contexts represent distinct firmware-visible DMA
+      address spaces and must not be used interchangeably.
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+  ports:
+    $ref: /schemas/graph.yaml#/properties/ports
+    description: |
+      DPU INTF output-only ports. The port number matches the firmware INTF
+      index. The corresponding DSI host is the child node whose reg value
+      matches the port number; the graph endpoint itself connects directly to
+      the attached panel. Unused INTF ports are omitted.
+    unevaluatedProperties: false
+    patternProperties:
+      "^port@[0-9a-f]+$":
+        $ref: /schemas/graph.yaml#/$defs/port-base
+        unevaluatedProperties: false
+        properties:
+          endpoint:
+            $ref: /schemas/graph.yaml#/$defs/endpoint-base
+            unevaluatedProperties: false
+            required:
+              - remote-endpoint
+
+patternProperties:
+  "^dsi@[0-9a-f]+$":
+    $ref: qcom,dcp-dsi.yaml#
+
+required:
+  - compatible
+  - iommus
+  - "#address-cells"
+  - "#size-cells"
+  - ports
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    dcp-subsystem {
+        compatible = "virtio,device34";
+        iommus = <&apps_smmu 0x400 0x2>;
+
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        ports {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            port@0 {
+                reg = <0>;
+                dcp_intf0_out: endpoint {
+                    remote-endpoint = <&panel_dcp_in>;
+                };
+            };
+        };
+
+        dsi@0 {
+            reg = <0>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            panel@0 {
+                compatible = "novatek,nt37801";
+                reg = <0>;
+
+                vddio-supply = <&vreg_l12b_1p8>;
+                vci-supply = <&vreg_l13b_3p0>;
+                vdd-supply = <&display_panel_vdd>;
+                reset-gpios = <&tlmm 210 GPIO_ACTIVE_LOW>;
+
+                port {
+                    panel_dcp_in: endpoint {
+                        remote-endpoint = <&dcp_intf0_out>;
+                    };
+                };
+            };
+        };
+    };
diff --git a/Documentation/devicetree/bindings/virtio/qcom,dcp-virtio.yaml b/Documentation/devicetree/bindings/virtio/qcom,dcp-virtio.yaml
new file mode 100644
index 000000000000..6020e848ce25
--- /dev/null
+++ b/Documentation/devicetree/bindings/virtio/qcom,dcp-virtio.yaml
@@ -0,0 +1,132 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/virtio/qcom,dcp-virtio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm DCP VirtIO transport
+
+maintainers:
+  - Jayant Shekhar <jayant.shekhar@xxxxxxxxxxxxxxxx>
+
+description: |
+  Qualcomm DCP VirtIO transport. The IPCC power-notify channel and
+  associated interrupts are required before the transport can access its
+  MMIO registers. This is a Qualcomm-specific transport and must not use the
+  generic virtio-mmio driver. The DCP VirtIO function is described as a child
+  node and is assigned to the registered VirtIO device by this transport.
+
+properties:
+  compatible:
+    const: qcom,dcp-virtio
+
+  reg:
+    maxItems: 1
+
+  interrupts-extended:
+    minItems: 2
+    maxItems: 2
+    description: The VirtIO-MMIO and DCP power-notify interrupts, in that order.
+
+  iommus:
+    maxItems: 1
+
+  iommu-ranges:
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    description: |
+      The firmware-visible IOVA range, specified as a four-cell tuple
+      containing a 64-bit IOVA base followed by a 64-bit range size.
+    items:
+      - description: IOVA base, high cell
+        $ref: /schemas/types.yaml#/definitions/uint32
+      - description: IOVA base, low cell
+        $ref: /schemas/types.yaml#/definitions/uint32
+      - description: IOVA range size, high cell
+        $ref: /schemas/types.yaml#/definitions/uint32
+      - description: IOVA range size, low cell
+        $ref: /schemas/types.yaml#/definitions/uint32
+
+  dma-coherent: true
+
+  mboxes:
+    maxItems: 1
+
+  mbox-names:
+    const: dcp-power-tx
+
+  dcp-subsystem:
+    $ref: ../display/msm/qcom,dcp.yaml#
+
+required:
+  - compatible
+  - reg
+  - interrupts-extended
+  - iommus
+  - iommu-ranges
+  - dma-coherent
+  - mboxes
+  - mbox-names
+  - dcp-subsystem
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/mailbox/qcom-ipcc.h>
+
+    virtio@9be8000 {
+        compatible = "qcom,dcp-virtio";
+        reg = <0x09be8000 0x1000>;
+        interrupts-extended = <&intc GIC_ESPI 956 IRQ_TYPE_LEVEL_HIGH>,
+                              <&ipcc 13 5 IRQ_TYPE_EDGE_RISING>;
+        iommus = <&apps_smmu 0x15a3 0x0>;
+        iommu-ranges = <0x0 0x84000000 0x0 0x04000000>;
+        dma-coherent;
+        mboxes = <&ipcc 13 5>;
+        mbox-names = "dcp-power-tx";
+
+        dcp-subsystem {
+            compatible = "virtio,device34";
+            iommus = <&apps_smmu 0x400 0x2>;
+
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            ports {
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                port@0 {
+                    reg = <0>;
+                    dcp_intf0_out: endpoint {
+                        remote-endpoint = <&panel_dcp_in>;
+                    };
+                };
+            };
+
+            dsi@0 {
+                reg = <0>;
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                panel@0 {
+                    compatible = "novatek,nt37801";
+                    reg = <0>;
+
+                    vddio-supply = <&vreg_l12b_1p8>;
+                    vci-supply = <&vreg_l13b_3p0>;
+                    vdd-supply = <&display_panel_vdd>;
+                    reset-gpios = <&tlmm 210 GPIO_ACTIVE_LOW>;
+
+                    port {
+                        panel_dcp_in: endpoint {
+                            remote-endpoint = <&dcp_intf0_out>;
+                        };
+                    };
+                };
+            };
+        };
+    };

-- 
2.43.0