Re: [PATCH] riscv: dts: fu540-c000: Add "status" property to cpu node

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Mon, Jul 22, 2019 at 9:35 PM Bin Meng <bmeng.cn@xxxxxxxxx> wrote:
>
> Hi Mark,
>
> On Mon, Jul 22, 2019 at 4:18 PM Mark Rutland <mark.rutland@xxxxxxx> wrote:
> >
> > On Fri, Jul 05, 2019 at 01:11:01PM +0800, Bin Meng wrote:
> > > On Fri, Jul 5, 2019 at 11:59 AM Anup Patel <Anup.Patel@xxxxxxx> wrote:
> > > >
> > > >
> > > >
> > > > > -----Original Message-----
> > > > > From: linux-riscv <linux-riscv-bounces@xxxxxxxxxxxxxxxxxxx> On Behalf Of Bin
> > > > > Meng
> > > > > Sent: Friday, July 5, 2019 9:23 AM
> > > > > To: linux-riscv <linux-riscv@xxxxxxxxxxxxxxxxxxx>; devicetree
> > > > > <devicetree@xxxxxxxxxxxxxxx>; Rob Herring <robh+dt@xxxxxxxxxx>; Mark
> > > > > Rutland <mark.rutland@xxxxxxx>; Albert Ou <aou@xxxxxxxxxxxxxxxxx>;
> > > > > Paul Walmsley <paul.walmsley@xxxxxxxxxx>; Palmer Dabbelt
> > > > > <palmer@xxxxxxxxxx>; Yash Shah <yash.shah@xxxxxxxxxx>
> > > > > Subject: [PATCH] riscv: dts: fu540-c000: Add "status" property to cpu node
> > > > >
> > > > > Per device tree spec, the "status" property property shall be present for
> > > > > nodes representing CPUs in a SMP configuration. This property is currently
> > > > > missing in cpu 1/2/3/4 node in the fu540-c000.dtsi.
> > > >
> > > > We don't need explicit "status = okay" for SOC internal devices
> > > > (such as PLIC, INTC, etc) which are always enabled by default.
> > > >
> > >
> > > Yes, that's fine because those device bindings do not require them.
> > >
> > > > Absence of "status" DT prop is treated as enabled by default.
> > > >
> > >
> > > But per current device tree spec, "status" in cpu node is mandatory.
> > > (spec uses "shall"). Missing it is a spec violation.
> >
> > I think this is a spec bug (or at least misleading wording in the spec).
> >
> > IEEE 1275 says (for status as a generic property):
> >
> >   The absence of this property menas that the operational status is unknown or
> >   okay.
>
> Yes, I checked IEEE 1275 doc, and it indeed says like you mentioned.
>
> However, it says "unknown" _or_ "okay", yet provides a definite value.
>
> >
> > ... and I think it's fine to treat that the same as an explicit "okay" here, as
> > we do generically in Linux.
>
> So what Linux does is a defacto interpretation?
>
> If everyone agrees this is a device tree spec bug, I will submit the
> patch to devicetree spec then.

Any comments from the device tree folks? thanks!

Regards,
Bin



[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]


  Powered by Linux