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>;
};
};
|
