On Thu, Nov 07, 2019 at 02:32:01PM -0800, Paul Walmsley wrote:
> On Thu, 7 Nov 2019, Christoph Hellwig wrote:
>
> > Add the binding for the trivial Qemu RISC-V poweroff mechanism, which is
>
> There's nothing RISC-V specific here. This IP isn't defined in the RISC-V
> specifications, or anything like that.
Does the VM have a spec or anything? Would be nice if it did. Would be
nicer still to just copy Arm's virt machine.
> Apparently it's a SiFive IP block which now has a virtual IP
> implementation in QEMU in hw/riscv/sifive_test.c. But since there's
> nothing RISC-V specific about this IP block, any QEMU system, with any CPU
> implementation, should be able to use this virtual IP, and this Linux
> driver.
>
> For these reasons, it's better if "RISC-V" is just removed from everywhere
> in this driver. If something needs to go in its place, "SiFive" may be
> better.
IIRC, there's already syscon poweroff binding. You could probably use
that.
>
>
> - Paul
>
>
> > just a single MMIO register exposed through the DT.
> >
> > Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> > ---
> > .../power/reset/qemu-riscv-virt-poweroff.txt | 16 ++++++++++++++++
> > 1 file changed, 16 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/power/reset/qemu-riscv-virt-poweroff.txt
> >
> > diff --git a/Documentation/devicetree/bindings/power/reset/qemu-riscv-virt-poweroff.txt b/Documentation/devicetree/bindings/power/reset/qemu-riscv-virt-poweroff.txt
> > new file mode 100644
> > index 000000000000..80ff6fd4e3b7
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/power/reset/qemu-riscv-virt-poweroff.txt
> > @@ -0,0 +1,16 @@
> > +QEMU RISC-V virt machine poweroff device
> > +
> > +This is a device in Qemu that can signal successful or error exit
> > +by writing two magic numbers to a trivial mmio register.
> > +A Linux poweroff is implemented as successful exit.
> > +
> > +Required Properties:
> > +-compatible: "sifive,test0"
> > +-reg: Specifies the physical address of the register
> > +
> > +Example:
> > +
> > + test@100000 {
> > + compatible = "sifive,test0";
> > + reg = <0x100000 0x1000>;
> > + };
> > --
> > 2.20.1
> >
> >
>
>
> - Paul
