Re: [PATCH 1/9] dt-bindings: Arm: Add Firmware Framework for Armv8-A (FF-A) binding
From: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
Date: 2020-09-01 16:05:40
Also in:
linux-arm-kernel
On Sat, 29 Aug 2020 18:09:15 +0100 Sudeep Holla [off-list ref] wrote:
From: Will Deacon <will@kernel.org> Add devicetree bindings for a FF-A-compliant hypervisor, its partitions and their memory regions. The naming is ludicrous but also not by fault. Signed-off-by: Will Deacon <will@kernel.org> (sudeep.holla: Dropped PSA from name and elsewhere as it seem to have disappeared mysteriously just before the final release) Signed-off-by: Sudeep Holla <redacted>
As I was reading this out of curiosity... I'm far from a yaml expert but a few things in line.
quoted hunk ↗ jump to hunk
--- .../devicetree/bindings/arm/arm,ffa.yaml | 102 ++++++++++++++++++ .../reserved-memory/arm,ffa-memory.yaml | 71 ++++++++++++ 2 files changed, 173 insertions(+) create mode 100644 Documentation/devicetree/bindings/arm/arm,ffa.yaml create mode 100644 Documentation/devicetree/bindings/reserved-memory/arm,ffa-memory.yamldiff --git a/Documentation/devicetree/bindings/arm/arm,ffa.yaml b/Documentation/devicetree/bindings/arm/arm,ffa.yaml new file mode 100644 index 000000000000..668a5995fcab --- /dev/null +++ b/Documentation/devicetree/bindings/arm/arm,ffa.yaml@@ -0,0 +1,102 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/arm,ffa.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Arm Firmware Framework for Arm v8-A + +maintainers: + - Will Deacon <will@kernel.org> + +description: | + Firmware frameworks implementing partition setup according to the FF-A + specification defined by ARM document number ARM DEN 0077A ("Arm Firmware + Framework for Arm v8-A") [0] must provide a "manifest and image" for each + partition to the "partition manager" so that the partition execution contexts + can be initialised. + + In the case of a virtual FFA instance, the manifest and image details can be + passed to the hypervisor (e.g. Linux KVM) using this binding. + + [0] https://developer.arm.com/docs/den0077/latest + +properties: + $nodename: + const: ffa_hyp + + compatible: + oneOf: + - const: arm,ffa-1.0-hypervisor
As below, would enum be more appropriate here?
+ + memory-region: + $ref: '/schemas/types.yaml#/definitions/phandle' + description: | + A phandle to the reserved memory region [1] to be used by the hypervisor. + The reserved memory region must be compatible with + "arm,ffa-1.0-hypervisor-memory-region". + + [1] Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt + +patternProperties: + "^ffa_partition[0-9]+$": + type: object + description: One or more child nodes, each describing an FFA partition. + properties: + $nodename: + const: ffa_partition + + compatible: + oneOf:
enum?
+ - const: arm,ffa-1.0-partition + + uuid: + $ref: '/schemas/types.yaml#definitions/string' + description: | + The 128-bit UUID [2] of the service implemented by this partition. + + [2] https://tools.ietf.org/html/rfc4122
Feels like we should be able to better type wise than a string for this but maybe not... Doesn't seem to be much in the way of precedence.
quoted hunk ↗ jump to hunk
+ + nr-exec-ctxs: + $ref: '/schemas/types.yaml#/definitions/uint32' + description: | + The number of virtual CPUs to instantiate for this partition. + + exec-state: + description: The execution state in which to execute the partition. + oneOf: + - const: "AArch64" + - const: "AArch32" + + entry-point: + $ref: '/schemas/types.yaml#/definitions/uint32-matrix' + description: | + The entry address of the partition specified as an Intermediate + Physical Address (IPA) encoded according to the '#address-cells' + property. + + memory-region: + $ref: '/schemas/types.yaml#/definitions/phandle-array' + description: | + A list of phandles to FFA reserved memory regions [3] for this + partition. + + [3] Documentation/devicetree/bindings/reserved-memory/arm,ffa-memory.yaml + +additionalProperties: false + +examples: + - | + ffa_hyp { + compatible = "arm,ffa-1.0-hypervisor"; + memory-region = <&ffa_hyp_reserved>; + + ffa_partition0 { + compatible = "arm,ffa-1.0-partition"; + uuid = "12345678-9abc-def0-1234-56789abcdef0"; + nr-exec-ctxs = <2>; + exec-state = "AArch64"; + entry-point = <0x80000>; + memory-region = <&ffa_reserved0 &ffa_reserved1>; + }; + };diff --git a/Documentation/devicetree/bindings/reserved-memory/arm,ffa-memory.yaml b/Documentation/devicetree/bindings/reserved-memory/arm,ffa-memory.yaml new file mode 100644 index 000000000000..5335e07abcfc --- /dev/null +++ b/Documentation/devicetree/bindings/reserved-memory/arm,ffa-memory.yaml@@ -0,0 +1,71 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/reserved-memory/arm,ffa-memory.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Memory Region for Arm Firmware Framework for Arm v8-A + +maintainers: + - Will Deacon <will@kernel.org> + +description: | + This binding allows a FF-A implementation to describe the normal memory + regions of a partition [1] to a hypervisor according to [2]. + + The physical address range reserved for the partition can be specified as a + static allocation using the 'reg' property or as a dynamic allocation using + the 'size' property. If both properties are omitted, then the hypervisor can + allocate physical memory for the partition however it sees fit. + + [1] Documentation/devicetree/bindings/arm/arm,ffa.yaml + [2] Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt + +properties: + $nodename: + pattern: "^ffa_mem(@[0-9a-f]+)?$" + + compatible: + oneOf: + - const: arm,ffa-1.0-partition-memory-region
If there is just element and it is const why not just?
compatible:
const: ....
I guess it sort of future proofs you for later variants...
However in that case, it would be more common to use
compatible:
enum:
- arm,ffa...
which is more restrictive but doesn't seem like you need the complexity of
oneOf and it's handling of sub schemas here.
+
+ ipa-range:
+ $ref: '/schemas/types.yaml#/definitions/uint32-matrix'
+ description: |
+ The Intermediate Physical Address (IPA) range (encoded in the same way as
+ a 'reg' property) at which to map the physical memory. If the IPA range is
+ larger than the physical memory region then the region is mapped starting
+ at the base of the IPA range.
+
+ read-only:
+ type: boolean
+ description: |
+ (static allocation only) The memory region has been pre-populated
+ by the firmware framework and must be mapped without write permission
+ at stage 2.
+
+ non-executable:
+ type: boolean
+ description: |
+ The memory region must be mapped without execute permission at stage 2.
+
+
+required:
+ - compatible
+
+# The "reserved-memory" binding defines additional properties.
+additionalProperties: true
+
+examples:
+ - |
+ reserved-memory {
+ #address-cells = <2>;
+ #size-cells = <2>;
+
+ ffa_reserved0: ffa_mem@100000000 {
+ compatible = "arm,ffa-1.0-partition-memory-region";
+ reg = <0x1 0x0 0x0 0x04000000>; // 64M @ 1GBIsn't that at 4GB?
+ ipa-range = <0x0 0x0 0x0 0x04000000>; // 64M @ 0x0 + read-only; + }; + };