From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH v2 1/5] dt-bindings: virtio: Specify #iommu-cells value for a virtio-iommu Date: Mon, 25 Jun 2018 13:27:53 -0600 Message-ID: <20180625192753.GA22351@rob-hp-laptop> References: <20180621190655.56391-1-jean-philippe.brucker@arm.com> <20180621190655.56391-2-jean-philippe.brucker@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20180621190655.56391-2-jean-philippe.brucker@arm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Jean-Philippe Brucker Cc: mark.rutland@arm.com, devicetree@vger.kernel.org, jayachandran.nair@cavium.com, lorenzo.pieralisi@arm.com, tnowicki@caviumnetworks.com, kvm@vger.kernel.org, virtio-dev@lists.oasis-open.org, joro@8bytes.org, mst@redhat.com, will.deacon@arm.com, virtualization@lists.linux-foundation.org, marc.zyngier@arm.com, iommu@lists.linux-foundation.org, eric.auger@redhat.com, robin.murphy@arm.com, kvmarm@lists.cs.columbia.edu List-Id: devicetree@vger.kernel.org On Thu, Jun 21, 2018 at 08:06:51PM +0100, Jean-Philippe Brucker wrote: > A virtio-mmio node may represent a virtio-iommu device. This is discovered > by the virtio driver at probe time, but the DMA topology isn't > discoverable and must be described by firmware. For DT the standard IOMMU > description is used, as specified in bindings/iommu/iommu.txt and > bindings/pci/pci-iommu.txt. Like many other IOMMUs, virtio-iommu > distinguishes masters by their endpoint IDs, which requires one IOMMU cell > in the "iommus" property. > > Signed-off-by: Jean-Philippe Brucker > --- > Documentation/devicetree/bindings/virtio/mmio.txt | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/Documentation/devicetree/bindings/virtio/mmio.txt b/Documentation/devicetree/bindings/virtio/mmio.txt > index 5069c1b8e193..337da0e3a87f 100644 > --- a/Documentation/devicetree/bindings/virtio/mmio.txt > +++ b/Documentation/devicetree/bindings/virtio/mmio.txt > @@ -8,6 +8,14 @@ Required properties: > - reg: control registers base address and size including configuration space > - interrupts: interrupt generated by the device > > +Required properties for virtio-iommu: > + > +- #iommu-cells: When the node describes a virtio-iommu device, it is > + linked to DMA masters using the "iommus" property as > + described in devicetree/bindings/iommu/iommu.txt. For > + virtio-iommu #iommu-cells must be 1, each cell describing > + a single endpoint ID. The iommus property should also be documented for the client side. Rob