From: Krzysztof Kozlowski <krzk@kernel.org>
To: Bibek Kumar Patro <bibek.patro@oss.qualcomm.com>
Cc: Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Joerg Roedel <joro@8bytes.org>, Rob Herring <robh@kernel.org>,
Krzysztof Kozlowski <krzk+dt@kernel.org>,
Conor Dooley <conor+dt@kernel.org>,
linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] dt-bindings: iommu: arm,smmu: Document optional interconnects property
Date: Mon, 18 May 2026 14:33:30 +0200 [thread overview]
Message-ID: <20260518-mellow-robust-caterpillar-93fcaa@quoll> (raw)
In-Reply-To: <20260516-smmu_interconnect_addition-v1-1-f889d933f5c1@oss.qualcomm.com>
On Sat, May 16, 2026 at 06:04:03PM +0530, Bibek Kumar Patro wrote:
> Some SoC implementations require a bandwidth vote on an interconnect
Then this should be disallowed for other devices in "allOf:".
> path before the SMMU register space is accessible. Add the optional
> 'interconnects' property to the binding to allow platform DT nodes
> to describe this path.
>
> The arm-smmu driver uses these properties to vote for bandwidth before
> accessing any SMMU registers and releases the vote on runtime suspend.
>
> Signed-off-by: Bibek Kumar Patro <bibek.patro@oss.qualcomm.com>
> ---
> Documentation/devicetree/bindings/iommu/arm,smmu.yaml | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> index 06fb5c8e7547cb7a92823adc2772b94f747376a6..5cbf944f2d3e178b3723d4dbaa19ee0d33446979 100644
> --- a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> @@ -243,6 +243,15 @@ properties:
> minItems: 1
> maxItems: 3
>
> + interconnects:
> + maxItems: 1
> + description:
> + Optional interconnect path to the SMMU register space. On some SoCs
> + the SMMU registers are only accessible after a bandwidth vote has been
Drivers are irrelevant here, drop. Also first sentence is redundant.
Schema says what is and what is not optional.
Best regards,
Krzysztof
next prev parent reply other threads:[~2026-05-18 12:33 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-16 12:34 [PATCH 0/2] iommu/arm-smmu: Add interconnect bandwidth voting support Bibek Kumar Patro
2026-05-16 12:34 ` [PATCH 1/2] dt-bindings: iommu: arm,smmu: Document optional interconnects property Bibek Kumar Patro
2026-05-18 12:33 ` Krzysztof Kozlowski [this message]
2026-05-19 13:53 ` Bibek Kumar Patro
2026-05-16 12:34 ` [PATCH 2/2] iommu/arm-smmu: Add interconnect bandwidth voting support Bibek Kumar Patro
2026-05-16 13:02 ` sashiko-bot
2026-05-23 14:41 ` Bibek Kumar Patro
2026-05-26 12:08 ` Bibek Kumar Patro
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