Based on kernel version 6.11
. Page generated on 2024-09-24 08:21 EST
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 | This document describes the generic device tree binding for describing the relationship between PCI(e) devices and IOMMU(s). Each PCI(e) device under a root complex is uniquely identified by its Requester ID (AKA RID). A Requester ID is a triplet of a Bus number, Device number, and Function number. For the purpose of this document, when treated as a numeric value, a RID is formatted such that: * Bits [15:8] are the Bus number. * Bits [7:3] are the Device number. * Bits [2:0] are the Function number. * Any other bits required for padding must be zero. IOMMUs may distinguish PCI devices through sideband data derived from the Requester ID. While a given PCI device can only master through one IOMMU, a root complex may split masters across a set of IOMMUs (e.g. with one IOMMU per bus). The generic 'iommus' property is insufficient to describe this relationship, and a mechanism is required to map from a PCI device to its IOMMU and sideband data. For generic IOMMU bindings, see Documentation/devicetree/bindings/iommu/iommu.txt. PCI root complex ================ Optional properties ------------------- - iommu-map: Maps a Requester ID to an IOMMU and associated IOMMU specifier data. The property is an arbitrary number of tuples of (rid-base,iommu,iommu-base,length). Any RID r in the interval [rid-base, rid-base + length) is associated with the listed IOMMU, with the IOMMU specifier (r - rid-base + iommu-base). - iommu-map-mask: A mask to be applied to each Requester ID prior to being mapped to an IOMMU specifier per the iommu-map property. Example (1) =========== / { #address-cells = <1>; #size-cells = <1>; iommu: iommu@a { reg = <0xa 0x1>; compatible = "vendor,some-iommu"; #iommu-cells = <1>; }; pci: pci@f { reg = <0xf 0x1>; compatible = "vendor,pcie-root-complex"; device_type = "pci"; /* * The sideband data provided to the IOMMU is the RID, * identity-mapped. */ iommu-map = <0x0 &iommu 0x0 0x10000>; }; }; Example (2) =========== / { #address-cells = <1>; #size-cells = <1>; iommu: iommu@a { reg = <0xa 0x1>; compatible = "vendor,some-iommu"; #iommu-cells = <1>; }; pci: pci@f { reg = <0xf 0x1>; compatible = "vendor,pcie-root-complex"; device_type = "pci"; /* * The sideband data provided to the IOMMU is the RID with the * function bits masked out. */ iommu-map = <0x0 &iommu 0x0 0x10000>; iommu-map-mask = <0xfff8>; }; }; Example (3) =========== / { #address-cells = <1>; #size-cells = <1>; iommu: iommu@a { reg = <0xa 0x1>; compatible = "vendor,some-iommu"; #iommu-cells = <1>; }; pci: pci@f { reg = <0xf 0x1>; compatible = "vendor,pcie-root-complex"; device_type = "pci"; /* * The sideband data provided to the IOMMU is the RID, * but the high bits of the bus number are flipped. */ iommu-map = <0x0000 &iommu 0x8000 0x8000>, <0x8000 &iommu 0x0000 0x8000>; }; }; Example (4) =========== / { #address-cells = <1>; #size-cells = <1>; iommu_a: iommu@a { reg = <0xa 0x1>; compatible = "vendor,some-iommu"; #iommu-cells = <1>; }; iommu_b: iommu@b { reg = <0xb 0x1>; compatible = "vendor,some-iommu"; #iommu-cells = <1>; }; iommu_c: iommu@c { reg = <0xc 0x1>; compatible = "vendor,some-iommu"; #iommu-cells = <1>; }; pci: pci@f { reg = <0xf 0x1>; compatible = "vendor,pcie-root-complex"; device_type = "pci"; /* * Devices with bus number 0-127 are mastered via IOMMU * a, with sideband data being RID[14:0]. * Devices with bus number 128-255 are mastered via * IOMMU b, with sideband data being RID[14:0]. * No devices master via IOMMU c. */ iommu-map = <0x0000 &iommu_a 0x0000 0x8000>, <0x8000 &iommu_b 0x0000 0x8000>; }; }; |