[PATCH 05/14] dt-bindings: remoteproc: Add Qualcomm RPM processor/subsystem

[Stephan Gerhold <stephan@gerhold.net>]

On Qualcomm platforms, most subsystems (e.g. audio/modem DSP) are
described as remote processors in the device tree, with a dedicated
node where properties and services related to them can be described.

The Resource Power Manager (RPM) is also such a subsystem, with a
remote processor that is running a special firmware. Unfortunately,
the RPM never got a dedicated node representing it properly in the
device tree. Most of the RPM services are described below a top-level
/smd or /rpm-glink node.

However, SMD/GLINK is just one of the communication channels to the RPM
firmware. For example, the MPM interrupt functionality provided by the
RPM does not use SMD/GLINK but writes directly to a special memory
region allocated by the RPM firmware in combination with a mailbox.
Currently there is no good place in the device tree to describe this
functionality. It doesn't belong below SMD/GLINK but it's not an
independent top-level device either.

Introduce a new "qcom,rpm-proc" compatible that allows describing the
RPM as a remote processor/subsystem like all others. The SMD/GLINK node
is moved to a "smd-edge"/"glink-edge" subnode consistent with other
existing bindings. Additional subnodes (e.g. interrupt-controller for
MPM, rpm-master-stats) can be also added there.

Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
---
 .../bindings/remoteproc/qcom,rpm-proc.yaml         | 125 +++++++++++++++++++++
 1 file changed, 125 insertions(+)

diff --git a/Documentation/devicetree/bindings/remoteproc/qcom,rpm-proc.yaml b/Documentation/devicetree/bindings/remoteproc/qcom,rpm-proc.yaml
new file mode 100644
index 000000000000..c06dd4f66503
--- /dev/null
+++ b/Documentation/devicetree/bindings/remoteproc/qcom,rpm-proc.yaml
@@ -0,0 +1,125 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/remoteproc/qcom,rpm-proc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm Resource Power Manager (RPM) Processor/Subsystem
+
+maintainers:
+  - Bjorn Andersson <andersson@kernel.org>
+  - Konrad Dybcio <konrad.dybcio@linaro.org>
+
+description:
+  Resource Power Manager (RPM) subsystem found in various Qualcomm platforms.
+  The RPM allows each component in the system to vote for state of the system
+  resources, such as clocks, regulators and bus frequencies. rpm-proc is the
+  top-level device tree node that groups all the RPM functionality together.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - qcom,apq8084-rpm-proc
+          - qcom,ipq6018-rpm-proc
+          - qcom,ipq9574-rpm-proc
+          - qcom,mdm9607-rpm-proc
+          - qcom,msm8226-rpm-proc
+          - qcom,msm8610-rpm-proc
+          - qcom,msm8909-rpm-proc
+          - qcom,msm8916-rpm-proc
+          - qcom,msm8917-rpm-proc
+          - qcom,msm8936-rpm-proc
+          - qcom,msm8937-rpm-proc
+          - qcom,msm8952-rpm-proc
+          - qcom,msm8953-rpm-proc
+          - qcom,msm8974-rpm-proc
+          - qcom,msm8976-rpm-proc
+          - qcom,msm8994-rpm-proc
+          - qcom,msm8996-rpm-proc
+          - qcom,msm8998-rpm-proc
+          - qcom,qcm2290-rpm-proc
+          - qcom,qcs404-rpm-proc
+          - qcom,sdm660-rpm-proc
+          - qcom,sm6115-rpm-proc
+          - qcom,sm6125-rpm-proc
+          - qcom,sm6375-rpm-proc
+      - const: qcom,rpm-proc
+
+  smd-edge:
+    $ref: /schemas/remoteproc/qcom,smd-edge.yaml#
+    description:
+      Qualcomm Shared Memory subnode which represents communication edge,
+      channels and devices related to the RPM subsystem.
+
+  glink-rpm:
+    $ref: /schemas/remoteproc/qcom,glink-rpm-edge.yaml#
+    description:
+      Qualcomm G-Link subnode which represents communication edge,
+      channels and devices related to the RPM subsystem.
+
+  interrupt-controller:
+    type: object
+    $ref: /schemas/interrupt-controller/qcom,mpm.yaml#
+    description:
+      MSM Power Manager (MPM) interrupt controller that monitors interrupts
+      when the system is asleep.
+
+  master-stats:
+    $ref: /schemas/soc/qcom/qcom,rpm-master-stats.yaml#
+    description:
+      Subsystem-level low-power mode statistics provided by RPM.
+
+required:
+  - compatible
+
+oneOf:
+  - required:
+      - smd-edge
+  - required:
+      - glink-rpm
+
+additionalProperties: false
+
+examples:
+  # SMD
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    remoteproc-rpm {
+      compatible = "qcom,msm8916-rpm-proc", "qcom,rpm-proc";
+
+      smd-edge {
+        interrupts = <GIC_SPI 168 IRQ_TYPE_EDGE_RISING>;
+        qcom,ipc = <&apcs 8 0>;
+        qcom,smd-edge = <15>;
+
+        rpm-requests {
+          compatible = "qcom,rpm-msm8916";
+          qcom,smd-channels = "rpm_requests";
+          /* ... */
+        };
+      };
+    };
+  # GLINK
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    remoteproc-rpm {
+      compatible = "qcom,qcm2290-rpm-proc", "qcom,rpm-proc";
+
+      glink-rpm {
+        compatible = "qcom,glink-rpm";
+        interrupts = <GIC_SPI 194 IRQ_TYPE_EDGE_RISING>;
+        qcom,rpm-msg-ram = <&rpm_msg_ram>;
+        mboxes = <&apcs_glb 0>;
+
+        rpm-requests {
+          compatible = "qcom,rpm-qcm2290";
+          qcom,glink-channels = "rpm_requests";
+          /* ... */
+        };
+      };
+    };

-- 
2.40.1