Re: [PATCH] arm64: dts: rockchip: enable the mmu600_pcie IOMMU on the rk3588 SoC

From: "Heiko Stübner" <heiko@sntech.de>
To: Niklas Cassel <cassel@kernel.org>, Niklas Cassel <Niklas.Cassel@wdc.com>
Cc: Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Damien Le Moal <dlemoal@kernel.org>,
	Sebastian Reichel <sebastian.reichel@collabora.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"linux-rockchip@lists.infradead.org"
	<linux-rockchip@lists.infradead.org>
Subject: Re: [PATCH] arm64: dts: rockchip: enable the mmu600_pcie IOMMU on the rk3588 SoC
Date: Mon, 18 Nov 2024 14:24:16 +0100	[thread overview]
Message-ID: <39365498.J2Yia2DhmK@diego> (raw)
In-Reply-To: <ZzsqdYUBNP7L9iRB@ryzen>

Hi Niklas,

Am Montag, 18. November 2024, 12:52:23 CET schrieb Niklas Cassel:
> On Thu, Nov 07, 2024 at 01:37:33PM +0100, Niklas Cassel wrote:
> > Commit cd81d3a0695c ("arm64: dts: rockchip: add rk3588 pcie and php
> > IOMMUs") added the rk3588 SoC's pcie IOMMU and php IOMMU as disabled.
> > 
> > The mmu600_pcie is connected with the five PCIe controllers.
> > See 8.2 Block Diagram, in rk3588 TRM (Technical Reference Manual).
> > 
> > The five PCIe controllers are:
> > pcie3x4, pcie3x2, pcie2x1l0, pcie2x1l1, pcie2x1l2.
> > 
> > pcie3x4 can run in either Root Complex mode or Endpoint mode, the other
> > four PCIe controllers can only run in Root Complex mode. To describe this
> > we thus have six different device nodes in the device tree.
> > 
> > A PCIe controller in Root Complex mode needs to specify an iommu-map, such
> > that the device knows how to convert a Requester ID (PCI BDF) to an IOMMU
> > master ID (stream ID). (A PCIe controller in Endpoint mode should use the
> > iommus property, just like a regular device.)
> > 
> > If you look at the device tree bindings for msi-map and iommu-map, you can
> > see that the conversion from Requester ID to MSI-specifier data is the same
> > as the conversion from Requester ID to IOMMU specifier data. Thus it is
> > sensible to define the iommu-map property value similar to the msi-map,
> > such that the conversion will be identical.
> > 
> > Add the proper iommu device tree properties for these six device nodes
> > connected to the mmu600_pcie, so that we can enable the mmu600_pcie IOMMU.
> > (The mmu600_php IOMMU is not touched, so it is still disabled.)
> > 
> > Signed-off-by: Niklas Cassel <cassel@kernel.org>
> > ---
> 
> Hello Heiko,
> 
> Any chance of getting this picked up?
> 
> (If not now, then at least for 6.14.)

Oh, definitly :-) ... it's marked as to look at.

For 6.14 ... the patch arrived shortly before -rc7, with PCIe stuff in it.
IOMMUs + PCIe is sort of a topic I'm cautious about shortly before
the merge window ;-)

Heiko

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