[PATCH v2 02/13] dt-bindings: cpus: add a thead vlen register length property
From: Charlie Jenkins <hidden>
Date: 2024-06-10 22:56:50
Also in:
linux-doc, linux-kselftest, linux-riscv, linux-sunxi, lkml
Subsystem:
open firmware and flattened device tree bindings, the rest · Maintainers:
Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds
Add a property analogous to the vlenb CSR so that software can detect the vector length of each CPU prior to it being brought online. Currently software has to assume that the vector length read from the boot CPU applies to all possible CPUs. On T-Head CPUs implementing pre-ratification vector, reading the th.vlenb CSR may produce an illegal instruction trap, so this property is required on such systems. Signed-off-by: Charlie Jenkins <redacted> --- Documentation/devicetree/bindings/riscv/cpus.yaml | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)
diff --git a/Documentation/devicetree/bindings/riscv/cpus.yaml b/Documentation/devicetree/bindings/riscv/cpus.yaml
index d87dd50f1a4b..a6bbbf658977 100644
--- a/Documentation/devicetree/bindings/riscv/cpus.yaml
+++ b/Documentation/devicetree/bindings/riscv/cpus.yaml@@ -26,6 +26,18 @@ description: | allOf: - $ref: /schemas/cpu.yaml# - $ref: extensions.yaml + - if: + not: + properties: + compatible: + contains: + enum: + - thead,c906 + - thead,c910 + - thead,c920 + then: + properties: + thead,vlenb: false properties: compatible:
@@ -94,6 +106,13 @@ properties: description: The blocksize in bytes for the Zicboz cache operations. + thead,vlenb: + $ref: /schemas/types.yaml#/definitions/uint32 + description: + VLEN/8, the vector register length in bytes. This property is required on + thead systems where the vector register length is not identical on all harts, or + the vlenb CSR is not available. + # RISC-V has multiple properties for cache op block sizes as the sizes # differ between individual CBO extensions cache-op-block-size: false
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2.44.0