Documentation/PCI/acpi-info.rst

1 .. SPDX-License-Identifier: GPL-2.0
12 method for accessing PCI config space below it, the address space windows
33 reserving address space.  The static tables are for things the OS needs to
39 If the OS is expected to manage a non-discoverable device described via
45 describe all the address space they consume.  This includes all the windows
50 These are all device-specific, non-architected things, so the only way a
52 the device-specific details.  The host bridge registers also include ECAM
53 space, since it is consumed by the host bridge.
58 spec defines Consumer/Producer only for the Extended Address Space
60 Address Space descriptors.  Consequently, OSes have to assume all
63 Prior to the addition of Extended Address Space descriptors, the failure of
66 bridge registers (including ECAM space) in PNP0C02 catch-all devices [6].
67 With the exception of ECAM, the bridge register space is device-specific
71 New architectures should be able to use "Consumer" Extended Address Space
74 ia64 kernels assume all address space descriptors, including "Consumer"
75 Extended Address Space ones, are windows, so it would not be safe to
78 PNP0C02 "motherboard" devices are basically a catch-all.  There's no
80 anything else."  So a PNP0C02 _CRS should claim any address space that is
84 The PCIe spec requires the Enhanced Configuration Access Method (ECAM)
86 ia64 SAL interface [7].  A host bridge consumes ECAM memory address space
87 and converts memory accesses into PCI configuration accesses.  The spec
88 defines the ECAM address space layout and functionality; only the base of
89 the address space is device-specific.  An ACPI OS learns the base address
92 The MCFG table must describe the ECAM space of non-hot pluggable host
94 a _CBA method in the PNP0A03 device describes the ECAM space of a
95 hot-pluggable host bridge [9].  Note that for both MCFG and _CBA, the base
101     For any device that is on a non-enumerable type of bus (for example, an
110     Each device enumerated by ACPI includes ACPI-defined objects in the
118     OSPM uses device configuration objects to configure hardware resources
119     for devices enumerated via ACPI.  Device configuration objects provide
137     QWord/DWord/Word Address Space Descriptor (.1, .2, .3)
140     Extended Address Space Descriptor (.4)
165     For systems that are PC-compatible, or that do not implement a
166     processor-architecture-specific firmware interface standard that allows
167     access to the Configuration Space, the ECAM is required as defined in
172     addresses corresponding to the non-hot removable PCI Segment Groups
174     boot. This is required for the PC-compatible systems.
181     The _CBA (Memory mapped Configuration Base Address) control method is
182     an optional ACPI object that returns the 64-bit memory mapped
183     configuration base address for the hot plug capable host bridge. The
184     base address returned by _CBA is processor-relative address. The _CBA
189     evaluates this structure to identify the memory mapped configuration
191     range specified in _CRS method. An ACPI name space object that contains