Re: [RFC PATCH 3/4] dt-bindings: power: reset: Document arm,psci-vendor-reset

[Elliot Berman]

On 7/25/2023 11:01 AM, Elliot Berman wrote:
> On 7/24/2023 4:23 PM, Rob Herring wrote:
> > On Mon, Jul 24, 2023 at 03:30:53PM -0700, Elliot Berman wrote:
> > > Add devicetree bindings for using PSCI SYSTEM_RESET2 with vendor 
> > > reset  types.
> > >
> > > Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx>
> > > ---
> > >   .../power/reset/arm,psci-vendor-reset.yaml    | 35 +++++++++++++++++++
> > >   MAINTAINERS                                   |  1 +
> > >   2 files changed, 36 insertions(+)
> > >   create mode 100644 
> > > Documentation/devicetree/bindings/power/reset/arm,psci-vendor-reset.yaml
> > >
> > > diff --git 
> > > a/Documentation/devicetree/bindings/power/reset/arm,psci-vendor-reset.yaml b/Documentation/devicetree/bindings/power/reset/arm,psci-vendor-reset.yaml
> > > new file mode 100644
> > > index 000000000000..18b0b8c167a1
> > > --- /dev/null
> > > +++ 
> > > b/Documentation/devicetree/bindings/power/reset/arm,psci-vendor-reset.yaml
> > > @@ -0,0 +1,35 @@
> > > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > > +# Copyright 2023 Qualcomm Innovation Center, Inc. All Rights Reserved.
> > > +%YAML 1.2
> > > +---
> > > +$id: 
> > > http://devicetree.org/schemas/power/reset/arm,psci-vendor-reset.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: PSCI SYSTEM_RESET2 Vendor Resets
> > > +
> > > +maintainers:
> > > +  - Elliot Berman <quic_eberman@xxxxxxxxxxx>
> > > +
> > > +description: |
> > > +  PSCI SYSTEM_RESET2 supports vendor-defined reset types. This 
> > > describes
> > > +  the conversion of reboot modes to the reset types.
> > > +
> > > +properties:
> > > +  compatible:
> > > +    const: arm,psci-vendor-reset
> > > +
> > > +allOf:
> > > +  - $ref: reboot-mode.yaml#
> > > +
> > > +additionalProperties: false
> > > +
> > > +examples:
> > > +  - |
> > > +    firmware {
> > > +      psci-vendor-resets {
> > > +        compatible = "arm,psci-vendor-reset";
> >
> > We already have a node for PSCI, we don't need a second one. You can
> > have a separate driver without a separate node.
>
> I could also place the reboot-mode functionality straight into 
> drivers/firwmare/psci/? I thought that might be more controversial than 
> separate driver, but maybe not?
>
> Mark/Loreno, do you have any concerns to add the reboot-mode driver 
> functionality directly in drivers/firmware/psci/psci.c?
>
> Sebastian, do you have any concerns to have this reboot-mode driver 
> outside drivers/power/reset/?

Sebastian, please disregard this question.

Mukesh pointed out that reboot-mode framework isn't the right option 
here since this driver does the actual reset and, as I understand, 
reboot-mode isn't intended to do actual reset. I'm going to implement 
something similar to what reboot-mode framework does but register 
against the restart_handler_list instead of reboot_notifier_list.

> > > +        reboot-normal = <0x100>;
> >
> > Wouldn't 'normal' be the normal PSCI reset?
>
> Ah, right. I had my head buried in the reboot-mode code when creating 
> the example. I can remove from the example.
>
> > > +        reboot-bootloader = <0x101>;
> > > +        reboot-fastboot = <0x102>;
> > > +      };
> > > +    };
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index d516295978a4..2da4c5f1917b 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -16982,6 +16982,7 @@ M:    Mark Rutland <mark.rutland@xxxxxxx>
> > >   M:    Lorenzo Pieralisi <lpieralisi@xxxxxxxxxx>
> > >   L:    linux-arm-kernel@xxxxxxxxxxxxxxxxxxx (moderated for 
> > > non-subscribers)
> > >   S:    Maintained
> > > +F:    
> > > Documentation/devicetree/bindings/power/reset/arm,psci-vendor-reset.yaml
> > >   F:    drivers/firmware/psci/
> > >   F:    include/linux/psci.h
> > >   F:    include/uapi/linux/psci.h
> > > --
> > > 2.41.0