linux-kernel - [PATCH v3 1/4] dt-bindings: interrupt-controller: sifive,plic: Document Renesas RZ/Five SoC

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Message-Id: <20220630100241.35233-2-samuel@sholland.org>
Date:   Thu, 30 Jun 2022 05:02:38 -0500
From:   Samuel Holland <samuel@...lland.org>
To:     Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
        Prabhakar <prabhakar.csengg@...il.com>,
        Marc Zyngier <maz@...nel.org>,
        Sagar Kadam <sagar.kadam@...ive.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>
Cc:     Guo Ren <guoren@...nel.org>, Thomas Gleixner <tglx@...utronix.de>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        linux-renesas-soc@...r.kernel.org,
        Biju Das <biju.das.jz@...renesas.com>,
        Samuel Holland <samuel@...lland.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Rob Herring <robh+dt@...nel.org>, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org
Subject: [PATCH v3 1/4] dt-bindings: interrupt-controller: sifive,plic: Document Renesas RZ/Five SoC

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>

Renesas RZ/Five (R9A07G043) SoC is equipped with NCEPLIC100 RISC-V
platform level interrupt controller from Andes Technology. NCEPLIC100
ignores subsequent EDGE interrupts until the previous EDGE interrupt is
completed, due to this issue we have to follow different interrupt flow
for EDGE and LEVEL interrupts.

This patch documents Renesas RZ/Five (R9A07G043) SoC.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Signed-off-by: Samuel Holland <samuel@...lland.org>
---

Changes in v3:
 - Add a more detailed explanation for why #interrupt-cells differs
 - Add andestech,nceplic100 as a fallback compatible
 - Separate the conditional part of the binding into two blocks (one for
   the PLIC implementation and the other for the SoC integration)

 .../sifive,plic-1.0.0.yaml                    | 64 +++++++++++++++++--
 1 file changed, 59 insertions(+), 5 deletions(-)

diff --git a/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.yaml b/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.yaml
index 27092c6a86c4..cd2b8bcaec3b 100644
--- a/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.yaml
+++ b/Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.yaml
@@ -26,9 +26,14 @@ description:
   with priority below this threshold will not cause the PLIC to raise its
   interrupt line leading to the context.
 
-  While the PLIC supports both edge-triggered and level-triggered interrupts,
-  interrupt handlers are oblivious to this distinction and therefore it is not
-  specified in the PLIC device-tree binding.
+  The PLIC supports both edge-triggered and level-triggered interrupts. For
+  edge-triggered interrupts, the RISC-V PLIC spec allows two responses to edges
+  seen while an interrupt handler is active; the PLIC may either queue them or
+  ignore them. In the first case, handlers are oblivious to the trigger type, so
+  it is not included in the interrupt specifier. In the second case, software
+  needs to know the trigger type, so it can reorder the interrupt flow to avoid
+  missing interrupts. This special handling is needed by at least the Renesas
+  RZ/Five SoC (AX45MP AndesCore with a NCEPLIC100).
 
   While the RISC-V ISA doesn't specify a memory layout for the PLIC, the
   "sifive,plic-1.0.0" device is a concrete implementation of the PLIC that
@@ -47,6 +52,10 @@ maintainers:
 properties:
   compatible:
     oneOf:
+      - items:
+          - enum:
+              - renesas,r9a07g043-plic
+          - const: andestech,nceplic100
       - items:
           - enum:
               - sifive,fu540-c000-plic
@@ -64,8 +73,7 @@ properties:
   '#address-cells':
     const: 0
 
-  '#interrupt-cells':
-    const: 1
+  '#interrupt-cells': true
 
   interrupt-controller: true
 
@@ -82,6 +90,12 @@ properties:
     description:
       Specifies how many external interrupts are supported by this controller.
 
+  clocks: true
+
+  power-domains: true
+
+  resets: true
+
 required:
   - compatible
   - '#address-cells'
@@ -91,6 +105,46 @@ required:
   - interrupts-extended
   - riscv,ndev
 
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - andestech,nceplic100
+
+    then:
+      properties:
+        '#interrupt-cells':
+          const: 2
+
+    else:
+      properties:
+        '#interrupt-cells':
+          const: 1
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: renesas,r9a07g043-plic
+
+    then:
+      properties:
+        clocks:
+          maxItems: 1
+
+        power-domains:
+          maxItems: 1
+
+        resets:
+          maxItems: 1
+
+      required:
+        - clocks
+        - power-domains
+        - resets
+
 additionalProperties: false
 
 examples:
-- 
2.35.1