On 31/10/2022 23:19, Elliot Berman wrote: > > > On 10/27/2022 12:55 PM, Krzysztof Kozlowski wrote: >> On 27/10/2022 12:17, Elliot Berman wrote: >>> Hi Rob, >>> >>> On 10/26/2022 2:16 PM, Rob Herring wrote: >>>> On Thu, Oct 13, 2022 at 6:59 PM Elliot Berman <quic_eberman@xxxxxxxxxxx> wrote: >>>>> >>>>> >>>>> On 10/12/2022 8:56 AM, Rob Herring wrote: >>>>>> On Mon, Oct 10, 2022 at 05:08:29PM -0700, Elliot Berman wrote: >>>>>>> When Linux is booted as a guest under the Gunyah hypervisor, the Gunyah >>>>>>> Resource Manager applies a devicetree overlay describing the virtual >>>>>>> platform configuration of the guest VM, such as the message queue >>>>>>> capability IDs for communicating with the Resource Manager. This >>>>>>> information is not otherwise discoverable by a VM: the Gunyah hypervisor >>>>>>> core does not provide a direct interface to discover capability IDs nor >>>>>>> a way to communicate with RM without having already known the >>>>>>> corresponding message queue capability ID. Add the DT bindings that >>>>>>> Gunyah adheres for the hypervisor node and message queues. >>>>>>> >>>>>>> Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx> >>>>>>> --- >>>>>>> .../bindings/firmware/gunyah-hypervisor.yaml | 87 +++++++++++++++++++ >>>>>>> MAINTAINERS | 1 + >>>>>>> 2 files changed, 88 insertions(+) >>>>>>> create mode 100644 Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml >>>>>>> >>>>>>> diff --git a/Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml b/Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml >>>>>>> new file mode 100644 >>>>>>> index 000000000000..f0a14101e2fd >>>>>>> --- /dev/null >>>>>>> +++ b/Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml >>>>>>> @@ -0,0 +1,87 @@ >>>>>>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) >>>>>>> +%YAML 1.2 >>>>>>> +--- >>>>>>> +$id: http://devicetree.org/schemas/firmware/gunyah-hypervisor.yaml# >>>>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml# >>>>>>> + >>>>>>> +title: Gunyah Hypervisor >>>>>>> + >>>>>>> +maintainers: >>>>>>> + - Murali Nalajala <quic_mnalajal@xxxxxxxxxxx> >>>>>>> + - Elliot Berman <quic_eberman@xxxxxxxxxxx> >>>>>>> + >>>>>>> +description: |+ >>>>>>> + On systems which support devicetree, Gunyah generates and overlays a deviceetree overlay which >>>>>> >>>>>> How you end up with the node (applying an overlay) is not relavent to >>>>>> the binding. >>>>>> >>>>>>> + describes the basic configuration of the hypervisor. Virtual machines use this information to determine >>>>>>> + the capability IDs of the message queues used to communicate with the Gunyah Resource Manager. >>>>>> >>>>>> Wrap at 80. That is the coding standard still though 100 is deemed >>>>>> allowed. And yamllint only complains at 110 because I didn't care to fix >>>>>> everyones lines over 100. >>>>>> >>>>>>> + See also: https://github.com/quic/gunyah-resource-manager/blob/develop/src/vm_creation/dto_construct.c >>>>>>> + >>>>>>> +properties: >>>>>>> + compatible: >>>>>>> + items: >>>>>>> + - const: gunyah-hypervisor-1.0 >>>>>>> + - const: gunyah-hypervisor >>>>>> >>>>>> 2 compatibles implies a difference between the 2. What's the difference? >>>>>> Where does '1.0' come from? >>>>>> >>>>> >>>>> There's no difference. I thought the convention was to have >>>>> device-specific compatible and the generic compatible. "device-specific" >>>>> here would be specific to version of Gunyah since it's software. >>>> >>>> No, that's just what people do because "vendor,new-soc", >>>> "vendor,old-soc" seems to bother them for some reason. At the end of >>>> the day, it's just a string identifier that means something. If >>>> there's no difference in that 'something', then there is no point in >>>> having more than one string. >>>> >>>> You only need something specific enough to discover the rest from the >>>> firmware. When that changes, then you add a new compatible. Of course, >>>> if you want existing OSs to work, then better not change the >>>> compatible. >>>> >>> >>> Thanks for the info, I'll drop the "-1.0" suffix. >> >> You still did not answer from where does 1.0 come from... Compatibles >> are usually expected to be specific. >> > > The 1.0 comes from the Gunyah version. This is the same version returned > by "hyp_identify" hypercall. Then dropping 1.0 makes sense - your SW provides auto-detection. Best regards, Krzysztof
