From: Jason Gunthorpe <jgg@ziepe.ca>
To: "Peng Fan (OSS)" <peng.fan@oss.nxp.com>
Cc: Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
"Joerg Roedel (AMD)" <joro@8bytes.org>,
Jean-Philippe Brucker <jpb@kernel.org>,
linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev,
linux-kernel@vger.kernel.org, Peng Fan <peng.fan@nxp.com>
Subject: Re: [PATCH RFC 0/4] iommu/arm-smmu-v3: Support shared Stream IDs
Date: Wed, 16 Sep 2026 13:10:18 -0300 [thread overview]
Message-ID: <20260916161018.GE3196566@ziepe.ca> (raw)
In-Reply-To: <20260916-smmu-shared-sid-v1-0-517384504aee@nxp.com>
On Wed, Sep 16, 2026 at 11:12:33PM +0800, Peng Fan (OSS) wrote:
> Some SoCs have a limited number of IOMMU Stream IDs (SIDs) and
> hardware that inherently shares them. For example, the NXP i.MX95
> eDMA controller has 64 channels where each TX/RX pair is assigned
> a single SID by the hardware - the two channel devices are distinct
> from Linux's perspective but present the same SID to the SMMU.
Is that a reflection of poor DT modelling though?
Why must a TX/RX *PAIR* have two platform_devices nodes?
Fix it there and you don't need any of this? Or is there more?
Jason
next prev parent reply other threads:[~2026-09-16 16:10 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-16 15:12 [PATCH RFC 0/4] iommu/arm-smmu-v3: Support shared Stream IDs Peng Fan (OSS)
2026-09-16 15:12 ` [PATCH RFC 1/4] iommu/arm-smmu-v3: Convert streams from RB tree to XArray Peng Fan (OSS)
2026-09-16 15:12 ` [PATCH RFC 2/4] iommu/arm-smmu-v3: Support shared SIDs in insert/remove_master Peng Fan (OSS)
2026-09-16 15:12 ` [PATCH RFC 3/4] iommu/arm-smmu-v3: Group aliasing devices into the same IOMMU group Peng Fan (OSS)
2026-09-16 15:12 ` [PATCH RFC 4/4] iommu/arm-smmu-v3: Wire up shared-SID STE ordering and feature gating Peng Fan (OSS)
2026-09-16 16:10 ` Jason Gunthorpe [this message]
2026-09-17 1:33 ` [PATCH RFC 0/4] iommu/arm-smmu-v3: Support shared Stream IDs Peng Fan
2026-09-17 14:48 ` Jason Gunthorpe
2026-09-18 11:48 ` Peng Fan
2026-09-18 12:11 ` Jason Gunthorpe
2026-09-18 13:41 ` Peng Fan
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