On Wed, Oct 9, 2019 at 7:08 PM Paul Walmsley <paul.walmsley@xxxxxxxxxx> wrote: > > On Wed, 9 Oct 2019, Rob Herring wrote: > > > Fix the errors in the RiscV CPU DT schema: > > > > Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: 'timebase-frequency' is a required property > > Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@1: 'timebase-frequency' is a required property > > Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: compatible:0: 'riscv' is not one of ['sifive,rocket0', 'sifive,e5', 'sifive,e51', 'sifive,u54-mc', 'sifive,u54', 'sifive,u5'] > > Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: compatible: ['riscv'] is too short > > Documentation/devicetree/bindings/riscv/cpus.example.dt.yaml: cpu@0: 'timebase-frequency' is a required property > > > > The DT spec allows for 'timebase-frequency' to be in 'cpu' or 'cpus' node > > and RiscV is doing nothing special with it, so just drop the definition > > here and don't make it required. > > The RISC-V kernel code does in fact parse it and use it, and we currently > rely on it being under /cpus: > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/riscv/kernel/time.c#n19 > > The RISC-V user ISA specification also constrains the timebase-frequency > to be the same across all CPUs, in section 10.1: > > https://github.com/riscv/riscv-isa-manual/releases/download/draft-20190608-f467e5d/riscv-spec.pdf > > So the right thing is to require 'timebase-frequency' at /cpus, and forbid > it in the individual CPU nodes. Yes, but this schema only deals with 'cpu' nodes and we can't check /cpus here. We'd need to write another schema matching on a child cpu node having a RiscV compatible. I can change this to 'timebase-frequency: false' to ban it here. That doesn't add too much as any undefined name is still allowed such as 'timbase-frequency'. There's a way to address this in json-schema draft8 with 'unevaluatedProperties', but that's not ready yet. Rob
