From:   Etienne Carriere <etienne.carriere@linaro.org>
To:     linux-kernel@vger.kernel.org
Cc:     linux-arm-kernel@lists.infradead.org,
        Etienne Carriere <etienne.carriere@linaro.org>,
        devicetree@vger.kernel.org,
        Jens Wiklander <jens.wiklander@linaro.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Marc Zyngier <maz@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Sumit Garg <sumit.garg@linaro.org>,
        Pascal Paillet <p.paillet@foss.st.com>
Subject: [PATCH v2 1/3] dt-bindings: arm: optee: add interrupt controller properties
Date:   Tue, 24 Jan 2023 11:56:41 +0100
Message-Id: <20230124105643.1737250-1-etienne.carriere@linaro.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Adds an optional interrupt controller property to optee firmware node
in the DT bindings. Optee driver may embeds an irqchip exposing
interrupts notified by the TEE world. Optee registers up to 1 interrupt
controller and identifies each line with a line number from 0 to
UINT16_MAX.

In the example, the platform SCMI device uses optee interrupt irq 5
as async signal to trigger processing of an async incoming SCMI message,
in the scope of a CPU DVFS control. A platform can have several SCMI
channels driven this way. Optee irqs also permits small embedded devices
to share e.g. a gpio expander, a group of wakeup sources, etc... between
OP-TEE world (for sensitive services) and Linux world (for non-sensitive
services). The physical controller is driven from the TEE which exposes
some controls to Linux kernel.

Cc: Jens Wiklander <jens.wiklander@linaro.org>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Sumit Garg <sumit.garg@linaro.org>

Co-developed-by: Pascal Paillet <p.paillet@foss.st.com>
Signed-off-by: Pascal Paillet <p.paillet@foss.st.com>
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
---
Changes since v1:
- Added a description to #interrupt-cells property.
- Changed of example. Linux wakeup event was subject to discussion and
  i don't know much about input events in Linux. So move to SCMI.
  In the example, an SCMI server in OP-TEE world raises optee irq 5
  so that Linux scmi optee channel &scmi_cpu_dvfs pushed in the incoming
  SCMI message in the scmi device for liekly later processing in threaded
  context. The example includes all parties: optee, scmi, sram, gic.
- Obviously rephrased the commit message.
- Added Cc: tags
---
 .../arm/firmware/linaro,optee-tz.yaml         | 67 +++++++++++++++++++
 1 file changed, 67 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.yaml b/Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.yaml
index d4dc0749f9fd..9c00c27f8b2c 100644
--- a/Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.yaml
+++ b/Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.yaml
@@ -40,6 +40,14 @@ properties:
       HVC #0, register assignments
       register assignments are specified in drivers/tee/optee/optee_smc.h
 
+  interrupt-controller: true
+
+  "#interrupt-cells":
+    const: 1
+    description: |
+      OP-TEE exposes irq for irp chip controllers from OP-TEE world. Each
+      irq is assigned a single line number identifier used as first argument.
+
 required:
   - compatible
   - method
@@ -64,3 +72,62 @@ examples:
             method = "hvc";
         };
     };
+
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    firmware  {
+        optee: optee {
+            compatible = "linaro,optee-tz";
+            method = "smc";
+            interrupts = <GIC_SPI 187 IRQ_TYPE_EDGE_RISING>;
+            interrupt-controller;
+            #interrupt-cells = <1>;
+        };
+
+        scmi {
+            compatible = "linaro,scmi-optee";
+            linaro,optee-channel-id = <0>;
+            interrupt-parent = <&gic>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            scmi_cpu_dvfs: protocol@13 {
+                reg = <0x13>;
+                linaro,optee-channel-id = <1>;
+                shmem = <&scmi_shm_tx>, <&scmi_shm_rx>;
+                interrupts-extended = <&optee 5>;
+                interrupt-names = "a2p";
+                #clock-cells = <1>;
+            };
+        };
+    };
+
+    gic: interrupt-controller@a0021000 {
+        compatible = "arm,cortex-a7-gic";
+        reg = <0xa0021000 0x1000>, <0xa0022000 0x2000>;
+        interrupt-controller;
+        #interrupt-cells = <3>;
+    };
+
+    soc {
+        #address-cells = <1>;
+        #size-cells = <1>;
+
+        sram@2ffff000 {
+            compatible = "mmio-sram";
+            reg = <0x2ffff000 0x1000>;
+            #address-cells = <1>;
+            #size-cells = <1>;
+            ranges = <0 0x2ffff000 0x1000>;
+
+            scmi_shm_tx: scmi-sram@0 {
+                compatible = "arm,scmi-shmem";
+                reg = <0 0x80>;
+            };
+
+            scmi_shm_rx: scmi-sram@100 {
+                compatible = "arm,scmi-shmem";
+                reg = <0x100 0x80>;
+            };
+        };
+    };
-- 
2.25.1