1#
2# Copyright 2020 NXP
3#
4# SPDX-License-Identifier:      GPL-2.0+
5#
6
7Specifying extra IOMMU mappings for PCI controllers
8
9This feature can be enabled through the PCI_IOMMU_EXTRA_MAPPINGS Kconfig option.
10
11The "pci_iommu_extra" env var or "pci-iommu-extra" device tree property (to be
12used for example in more static scenarios such as hardwired PCI endpoints that
13get initialized later in the system setup) allows two things:
14 - for a SRIOV capable PCI EP identified by its B.D.F specify the maximum number
15   of VFs that will ever be created for it
16 - for hot-plug case, specify the B.D.F with which the device will show up on
17   the PCI bus
18
19The env var consists of a list of <bdf>,<action> pairs for a certain pci bus
20identified by its controller's base register address, as defined in the "reg"
21property in the device tree.
22
23pci_iommu_extra = pci@<addr1>,<bdf>,<action>,<bdf>,<action>,
24		  pci@<addr2>,<bdf>,<action>,<bdf>,<action>,...
25
26where:
27 <addr> is the base register address of the pci controller for which the
28        subsequent <bdf>,<action> pairs apply
29 <bdf> identifies to which B.D.F the action applies to
30 <action> can be:
31    - "vfs=<number>" to specify that for the PCI EP identified previously by
32      the <bdf> to include mappings for <number> of VFs.
33      The variant "noari_vfs=<number>" is available to disable taking ARI into
34      account.
35    - "hp" to specify that on this <bdf> there will be a hot-plugged device so
36      it needs a mapping
37The device tree property must be placed under the correct pci controller node
38and only the bdf and action pairs need to be specified, like this:
39
40pci-iommu-extra = "<bdf>,<action>,<bdf>,<action>,...";
41
42Note: the env var has priority over the device tree property.
43
44For example, given this configuration on bus 6:
45
46=> pci 6
47Scanning PCI devices on bus 6
48BusDevFun  VendorId   DeviceId   Device Class       Sub-Class
49_____________________________________________________________
5006.00.00   0x8086     0x1572     Network controller      0x00
5106.00.01   0x8086     0x1572     Network controller      0x00
52
53The following u-boot env var will create iommu mappings for 3 VFs for each PF:
54
55=> setenv pci_iommu_extra pci@0x3800000,6.0.0,vfs=3,6.0.1,vfs=3
56
57For the device tree case, this would be specified like this:
58
59pci-iommu-extra = "6.0.0,vfs=3,6.0.1,vfs=3";
60
61To add an iommu mapping for a hot-plugged device, please see following example:
62
63=> setenv pci_iommu_extra pci@0x3800000,2.16.0,hp
64
65For the device tree case, this would be specified like this:
66
67pci-iommu-extra = "2.16.0,hp";
68