On Tue, Mar 08, 2022 at 02:13:33PM -0600, Rob Herring wrote: > On Mon, Mar 07, 2022 at 08:17:44AM +0000, Oleksii Moisieiev wrote: > > Document xen,scmi-devid property for the devices, using SCMI protocol > > to work with clocks/resets/power-domains etc. This property is intended > > to set the device_id, which should be used to manage device permissions > > in the Firmware. Device permissions management described in DEN 0056, > > Section 4.2.2.10 [0]. > > If device_id is a SCMI thing, how is it set for other platforms and > bindings? With clocks or power-domains, the device_id is the cell value, > right? > > Since we don't yet have a device assignment, security, or partitioning > binding, you've come up with some Xen specific solution. Given I know > multiple people want some sort of binding for this, I'm not going to > accept anything short of a common binding addressing the various needs. > Hi Sudeep, On your email from 3/4/2022 you wrote: > The fact that we don't need this to be part of SCMI OSPM user bindings, > it is not addressed and can be considered as a gap. > + The reason I want to keep it xen specific at the moment as we had some > plan to extended the device-id usage in the spec which hasn't progressed > a bit(I must admit that before you ask), and this addition should not be > obstruct that future development. If we align with what we define xen > specific as part of $subject work, we can always define generic binding > in the future and slowly make the other obsolete over the time. IIUC you have some plans to provide device_id support to the device-tree bindings from your side. Maybe we can discuss some of your plans here and we can come up with the generic device-id binding? So I will have something to base on in Xen. Best regards, Oleksii. > > > This property is used by Xen hypervisor, which works as trusted Agent, to > > set permissions for the devices, passed-through to the Guest Domains, > > which are non-trusted Agents. Trusted and non-trusted Agent terms described > > in Section 4.1.1 [0]. > > > > [0] https://urldefense.com/v3/__https://developer.arm.com/documentation/den0056/latest__;!!GF_29dbcQIUBPA!kOUan6_nwTf375KaLzZxwHSYqYp1ptLUolUEoK-t3Wb4gsN3ajUC0qQBh6TdAMXQYrn8$ [developer[.]arm[.]com] > > > > Signed-off-by: Oleksii Moisieiev <oleksii_moisieiev@xxxxxxxx> > > --- > > .../bindings/firmware/xen,scmi-devid.yaml | 42 +++++++++++++++++++ > > 1 file changed, 42 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/firmware/xen,scmi-devid.yaml > > > > diff --git a/Documentation/devicetree/bindings/firmware/xen,scmi-devid.yaml b/Documentation/devicetree/bindings/firmware/xen,scmi-devid.yaml > > new file mode 100644 > > index 000000000000..49dc9951b54d > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/firmware/xen,scmi-devid.yaml > > @@ -0,0 +1,42 @@ > > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) > > +# Copyright 2022 EPAM Systems. > > +%YAML 1.2 > > +--- > > +$id: https://urldefense.com/v3/__http://devicetree.org/schemas/firmware/xen,scmi-devid.yaml*__;Iw!!GF_29dbcQIUBPA!kOUan6_nwTf375KaLzZxwHSYqYp1ptLUolUEoK-t3Wb4gsN3ajUC0qQBh6TdAPJC8yo3$ [devicetree[.]org] > > +$schema: https://urldefense.com/v3/__http://devicetree.org/meta-schemas/core.yaml*__;Iw!!GF_29dbcQIUBPA!kOUan6_nwTf375KaLzZxwHSYqYp1ptLUolUEoK-t3Wb4gsN3ajUC0qQBh6TdADgb5MTo$ [devicetree[.]org] > > + > > +title: Xen SCMI (System Control and Management Interface) Device ID binding > > + > > +maintainers: > > + - Oleksii Moisieiev <oleksii_moisieiev@xxxxxxxx> > > + > > +select: true > > + > > +description: | > > + SCMI device_id property is intended to set the device id, needed to manage > > + the device permissions via SCMI protocol in the firmware. The device_id > > + should match device ids, defined in the firmware so the device permissions > > + can be requested by sending BASE_SET_DEVICE_PERMISSIONS (see 4.2.2.10 of [0]). > > + > > + This property is used by Xen hypervisor to set the device permissions for > > + the Guest Domains. Where Xen is trusted Agent and Guest Domains are > > + non-trusted Agents. > > + > > + [0] https://urldefense.com/v3/__https://developer.arm.com/documentation/den0056/latest__;!!GF_29dbcQIUBPA!kOUan6_nwTf375KaLzZxwHSYqYp1ptLUolUEoK-t3Wb4gsN3ajUC0qQBh6TdAMXQYrn8$ [developer[.]arm[.]com] > > + > > +properties: > > + xen,scmi-devid: > > + description: Identifier of the device, matching device id, defined in > > + the firmware. > > + $ref: /schemas/types.yaml#/definitions/uint32 > > + > > +additionalProperties: true > > + > > +examples: > > + - | > > + ohci1: usb@ee0a0000 { > > + /* ... */ > > + reg = <0xee0a0000 0x100>; > > + xen,scmi-devid = <11>; > > This will cause validation errors unless xen,scmi-devid is listed or > this schema is referenced in every possible device schema. That > doesn't scale, but we don't really have a solution to that. For some > common properties, the tools will add certain properties. If we > come up with something common, we'll need to add it. Or we may > need to come up with something more data driven where certain schemas > are automatically added. > > Rob > > > + clocks = <&scmi_clock 4>; > > + }; > > -- > > 2.27.0 > >
