Hi guys, On Tue, Aug 27, 2019 at 10:18:46PM +0800, Jiaxun Yang wrote: > On 2019/8/27 下午8:45, Rob Herring wrote: > > On Tue, Aug 27, 2019 at 3:55 AM Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx> wrote: > > > diff --git a/Documentation/devicetree/bindings/mips/loongson/cpus.yaml b/Documentation/devicetree/bindings/mips/loongson/cpus.yaml > > > new file mode 100644 > > > index 000000000000..410d896a0078 > > > --- /dev/null > > > +++ b/Documentation/devicetree/bindings/mips/loongson/cpus.yaml > > > @@ -0,0 +1,38 @@ > > > +# SPDX-License-Identifier: GPL-2.0 > > Dual license for new bindings please: > > > > (GPL-2.0-only OR BSD-2-Clause) > > > > > +%YAML 1.2 > > > +--- > > > +$id: http://devicetree.org/schemas/mips/loongson/cpus.yaml# > > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > > + > > > +title: Loongson CPUs bindings > > > + > > > +maintainers: > > > + - Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx> > > > + > > > +description: |+ > > > + The device tree allows to describe the layout of CPUs in a system through > > > + the "cpus" node, which in turn contains a number of subnodes (ie "cpu") > > > + defining properties for every cpu. > > > + > > > + Bindings for CPU nodes follow the Devicetree Specification, available from: > > > + > > > + https://www.devicetree.org/specifications/ > > > + > > > +properties: > > > + reg: > > > + maxItems: 1 > > > + description: | > > > + Physical ID of a CPU, Can be read from CP0 EBase.CPUNum. > > Is this definition specific to Loongson CPUs or all MIPS? > > Currently it's specific to Loongson CPU only, as other processors may using > different method to express CPU map. > > Different from Arm, MIPS family of processors seems less uniform and have > their own designs. > > For this point, we'd better ask Paul's opinion. In general on MIPS we detect CPU properties at runtime from coprocessor 0 registers & similar sources of information, so there's not really a need to specify anything about the CPU in devicetree. For example here you say yourself that the value for this property can be read from EBase.CPUNum - so why specify it in DT? Thanks, Paul
