From 6778948f9de86c3cfaf36725a7c87dcff9ba247f Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Mon, 11 Dec 2023 08:20:59 +0000
Subject: [PATCH] kernel_5.10 no rt
---
kernel/Documentation/devicetree/bindings/virtio/mmio.txt | 32 +++++++++++++++++++++++++++++++-
1 files changed, 31 insertions(+), 1 deletions(-)
diff --git a/kernel/Documentation/devicetree/bindings/virtio/mmio.txt b/kernel/Documentation/devicetree/bindings/virtio/mmio.txt
index 5069c1b..0a575f3 100644
--- a/kernel/Documentation/devicetree/bindings/virtio/mmio.txt
+++ b/kernel/Documentation/devicetree/bindings/virtio/mmio.txt
@@ -1,6 +1,6 @@
* virtio memory mapped device
-See http://ozlabs.org/~rusty/virtio-spec/ for more details.
+See https://ozlabs.org/~rusty/virtio-spec/ for more details.
Required properties:
@@ -8,10 +8,40 @@
- 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 corresponds to a virtio-iommu device, it is
+ linked to DMA masters using the "iommus" or "iommu-map"
+ properties [1][2]. #iommu-cells specifies the size of the
+ "iommus" property. For virtio-iommu #iommu-cells must be
+ 1, each cell describing a single endpoint ID.
+
+Optional properties:
+
+- iommus: If the device accesses memory through an IOMMU, it should
+ have an "iommus" property [1]. Since virtio-iommu itself
+ does not access memory through an IOMMU, the "virtio,mmio"
+ node cannot have both an "#iommu-cells" and an "iommus"
+ property.
+
Example:
virtio_block@3000 {
compatible = "virtio,mmio";
reg = <0x3000 0x100>;
interrupts = <41>;
+
+ /* Device has endpoint ID 23 */
+ iommus = <&viommu 23>
}
+
+ viommu: iommu@3100 {
+ compatible = "virtio,mmio";
+ reg = <0x3100 0x100>;
+ interrupts = <42>;
+
+ #iommu-cells = <1>
+ }
+
+[1] Documentation/devicetree/bindings/iommu/iommu.txt
+[2] Documentation/devicetree/bindings/pci/pci-iommu.txt
--
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