Re: [PATCH V5 18/30] dt-bindings: csky CPU Bindings

Guo Ren
2018-09-28T01:03:38Z

On Thu, Sep 27, 2018 at 11:43:17AM -0500, Rob Herring wrote:
> On Tue, Sep 25, 2018 at 07:39:21AM +0800, Guo Ren wrote:
> > This patch adds the documentation to describe that how to add cpu nodes in
> > dts for SMP.
> >
> > Signed-off-by: Guo Ren <ren_guo@c-sky.com>
> > ---
> > Documentation/devicetree/bindings/csky/cpus.txt | 70 +++++++++++++++++++++++++
> > 1 file changed, 70 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/csky/cpus.txt
> >
> > diff --git a/Documentation/devicetree/bindings/csky/cpus.txt b/Documentation/devicetree/bindings/csky/cpus.txt
> > new file mode 100644
> > index 0000000..ee3901d
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/csky/cpus.txt
> > @@ -0,0 +1,70 @@
> > +==================
> > +C-SKY CPU Bindings
> > +==================
> > +
> > +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.
> > +
> > +Only SMP system need to care about the cpus node and single processor
> > +needn't define cpus node at all.
>
> We've generally found this is not true. Even for single core, you can
> have power domains, clocks for DVFS, etc.
Ok, I'll remove it.

>
> > +
> > +=====================================
> > +cpus and cpu node bindings definition
> > +=====================================
> > +
> > +- cpus node
> > +
> > + Description: Container of cpu nodes
> > +
> > + The node name must be "cpus".
> > +
> > + A cpus node must define the following properties:
> > +
> > + - #address-cells
> > + Usage: required
> > + Value type: <u32>
> > + Definition: must be set to 1
> > + - #size-cells
> > + Usage: required
> > + Value type: <u32>
> > + Definition: must be set to 0
> > +
> > +- cpu node
> > +
> > + Description: Describes one of SMP cores
> > +
> > + PROPERTIES
> > +
>
> You need a compatible property for cpu nodes.
Our cpu is defined in defconfig, not in dts. I could put a comatible
property in here, but it's no use in code.
>
> > + - device_type
> > + Usage: required
> > + Value type: <string>
> > + Definition: must be "cpu"
> > + - reg
> > + Usage: required
> > + Value type: <u32>
> > + Definition: CPU index
> > + - status:
>
> You don't need to document status here.
ok, remove the status description.

Best Regards
Guo Ren