Re: [PATCH 2/5] dt-bindings: iommu: verisilicon: Add binding for VSI IOMMU

From: Benjamin Gaignard <benjamin.gaignard@collabora.com>
To: Conor Dooley <conor@kernel.org>
Cc: joro@8bytes.org, will@kernel.org, robin.murphy@arm.com,
	robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org,
	heiko@sntech.de, nicolas.dufresne@collabora.com,
	p.zabel@pengutronix.de, mchehab@kernel.org,
	iommu@lists.linux.dev, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, linux-media@vger.kernel.org,
	kernel@collabora.com
Subject: Re: [PATCH 2/5] dt-bindings: iommu: verisilicon: Add binding for VSI IOMMU
Date: Mon, 16 Jun 2025 17:50:50 +0200	[thread overview]
Message-ID: <2d251d7c-7906-4a66-9791-7f71e7a4b54d@collabora.com> (raw)
In-Reply-To: <20250616-contempt-remix-5af2b7281cbd@spud>

Le 16/06/2025 à 17:42, Conor Dooley a écrit :
> On Mon, Jun 16, 2025 at 05:30:44PM +0200, Benjamin Gaignard wrote:
>> Le 16/06/2025 à 17:14, Conor Dooley a écrit :
>>> On Mon, Jun 16, 2025 at 04:55:50PM +0200, Benjamin Gaignard wrote:
>>>> Add a device tree binding for the Verisilicon (VSI) IOMMU. This IOMMU sits
>>>> in front of hardware encoder and decoder blocks on SoCs using Verisilicon IP,
>>>> such as the Rockchip RK3588.
>>>>
>>>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
>>>> ---
>>>>    .../bindings/iommu/verisilicon,iommu.yaml     | 71 +++++++++++++++++++
>>>>    1 file changed, 71 insertions(+)
>>>>    create mode 100644 Documentation/devicetree/bindings/iommu/verisilicon,iommu.yaml
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/iommu/verisilicon,iommu.yaml b/Documentation/devicetree/bindings/iommu/verisilicon,iommu.yaml
>>>> new file mode 100644
>>>> index 000000000000..acef855fc61d
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/iommu/verisilicon,iommu.yaml
>>>> @@ -0,0 +1,71 @@
>>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>>> +%YAML 1.2
>>>> +---
>>>> +$id: http://devicetree.org/schemas/iommu/verisilicon,iommu.yaml#
>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>> +
>>>> +title: Verisilicon IOMMU
>>>> +
>>>> +maintainers:
>>>> +  - Benjamin Gaignard <benjamin.gaignard@collabora.com>
>>>> +
>>>> +description: |+
>>>> +  A Versilicon iommu translates io virtual addresses to physical addresses for
>>>> +  its associated video decoder.
>>>> +
>>>> +properties:
>>>> +  compatible:
>>>> +    oneOf:
>>>> +      - items:
>>>> +          - const: verisilicon,iommu
>>> You're missing a soc-specific compatible at the very least here, but is
>>> there really no versioning on the IP at all? I'd be surprised if
>>> verisilicon only produced exactly one version of an iommu IP.
>> I only aware this version of the iommu for the moment.
> "for the moment", yeah. Is there any information that could be used to
> version this available?

The hardware block isn't documented in the TRM so I don't know if there is a version
field or something like that.

>
>> Does adding verisilicon,rk3588-iommu sound good for you ?
> It'd be "rockchip,rk3588-iommu", but sure.

"rockchip,rk3588-iommu" is already use for other MMUs in rk3588.

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