Re: [PATCH v3 3/4] dt-bindings: rng: Add vmgenid support

From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To: Sudan Landge <sudanl@amazon.com>,
	tytso@mit.edu, Jason@zx2c4.com, robh+dt@kernel.org,
	krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
	sathyanarayanan.kuppuswamy@linux.intel.com,
	thomas.lendacky@amd.com, dan.j.williams@intel.com,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: graf@amazon.de, dwmw@amazon.co.uk, bchalios@amazon.es,
	xmarcalx@amazon.co.uk
Subject: Re: [PATCH v3 3/4] dt-bindings: rng: Add vmgenid support
Date: Mon, 25 Mar 2024 22:59:43 +0100	[thread overview]
Message-ID: <e94eb9cd-6f55-41d9-9e91-fe2ec43c3cbf@linaro.org> (raw)
In-Reply-To: <20240325195306.13133-4-sudanl@amazon.com>

On 25/03/2024 20:53, Sudan Landge wrote:
> Virtual Machine Generation ID driver was introduced in commit af6b54e2b5ba
> ("virt: vmgenid: notify RNG of VM fork and supply generation ID"), as an
> ACPI only device.

...

> diff --git a/Documentation/devicetree/bindings/rng/vmgenid.yaml b/Documentation/devicetree/bindings/rng/vmgenid.yaml
> new file mode 100644
> index 000000000000..24643080d6b0
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/rng/vmgenid.yaml
> @@ -0,0 +1,58 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/rng/vmgenid.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Virtual Machine Generation Counter ID device
> +
> +maintainers:
> +  - Jason A. Donenfeld <Jason@zx2c4.com>
> +
> +description:
> +  Firmwares or hypervisors can use this devicetree to describe
> +  interrupts and the shared resources to inject a Virtual Machine Generation
> +  counter.
> +
> +properties:
> +  compatible:
> +    const: virtual,vmgenctr
> +
> +  "#interrupt-cells":
> +    const: 3
> +    description:
> +      The 1st cell is the interrupt type.
> +      The 2nd cell contains the interrupt number for the interrupt type.
> +      The 3rd cell is for trigger type and level flags.

How is this interrupt-controller now? You already got such comment on v2.

> +
> +  interrupt-map: true
> +
> +  reg:
> +    description:
> +      The 1st cell specifies the base physical address of the 8-byte aligned
> +      buffer in guest memory space which is guaranteed not to be used by the
> +      operating system.
> +      The 2nd cell specifies the size of the buffer which holds the VMGenID.
> +    maxItems: 1
> +
> +  interrupts:
> +    description:
> +      interrupt used to notify that a new VMGenID counter is available.
> +    maxItems: 1
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    rng@80000000 {
> +      compatible = "virtual,vmgenctr";
> +      reg = <0x80000000 0x1000>;
> +      interrupts = <0x00 0x23 0x01>;

Use standard defines and drop padding from hex numbers. Or just use
decimal numbers because hex is anyway unusual, unless this is what your
device datasheet says.

And what is 0x00 in the interrupt?

Best regards,
Krzysztof