On 5/9/23 3:47 PM, 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.
Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx>
Rob has reviewed this so I presume it's fine, but I wonder
why there's no "qcom," prefix on the compatible strings.
It also seems like there might be more bindings to define
for Gunyah. See a few more comments below.
-Alex
---
.../bindings/firmware/gunyah-hypervisor.yaml | 82 +++++++++++++++++++
1 file changed, 82 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..3fc0b043ac3c
--- /dev/null
+++ b/Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
@@ -0,0 +1,82 @@
+# 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:
+ - Prakruthi Deepak Heragu <quic_pheragu@xxxxxxxxxxx>
+ - Elliot Berman <quic_eberman@xxxxxxxxxxx>
+
+description: |+
+ Gunyah virtual machines use this information to determine the capability IDs
+ of the message queues used to communicate with the Gunyah Resource Manager.
+ See also: https://github.com/quic/gunyah-resource-manager/blob/develop/src/vm_creation/dto_construct.c
Looking at dto_create_msg_queue() at the above link, it seems
that Gunyah message queues and capabilities get represented
in DTS, but I don't see those things documented in bindings.
I might be misinterpreting that code, but if not, should
these other things be documented as well?
+
+properties:
+ compatible:
+ const: gunyah-hypervisor
Should this be qcom,gunyah-hypervisor?
+
+ "#address-cells":
+ description: Number of cells needed to represent 64-bit capability IDs.
+ const: 2
+
+ "#size-cells":
+ description: must be 0, because capability IDs are not memory address
+ ranges and do not have a size.
+ const: 0
+
+patternProperties:
+ "^gunyah-resource-mgr(@.*)?":
+ type: object
+ description:
+ Resource Manager node which is required to communicate to Resource
+ Manager VM using Gunyah Message Queues.
+
+ properties:
+ compatible:
+ const: gunyah-resource-manager
Here too, should this be qcom,gunyah-resource-manager?
+
+ reg:
+ items:
+ - description: Gunyah capability ID of the TX message queue
+ - description: Gunyah capability ID of the RX message queue
+
+ interrupts:
+ items:
+ - description: Interrupt for the TX message queue
+ - description: Interrupt for the RX message queue
+
+ additionalProperties: false
+
+ required:
+ - compatible
+ - reg
+ - interrupts
+
+additionalProperties: false
+
+required:
+ - compatible
+ - "#address-cells"
+ - "#size-cells"
+
+examples:
+ - |
+ #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+ hypervisor {
+ #address-cells = <2>;
+ #size-cells = <0>;
+ compatible = "gunyah-hypervisor";
+
+ gunyah-resource-mgr@0 {
+ compatible = "gunyah-resource-manager";
+ interrupts = <GIC_SPI 3 IRQ_TYPE_EDGE_RISING>, /* TX full IRQ */
+ <GIC_SPI 4 IRQ_TYPE_EDGE_RISING>; /* RX empty IRQ */
+ reg = <0x00000000 0x00000000>, <0x00000000 0x00000001>;
+ /* TX, RX cap ids */
+ };
+ };
