On Wed, 4 May 2022, Arnd Bergmann wrote:
> Almost all architectures that support CONFIG_PCI also provide
> HAS_IOPORT today (at least at compile time, if not at runtime),
> with s390 as a notable exception. Any machines that have legacy
> PCI device support will also have I/O ports because a lot of
> legacy PCI cards used it, and any machine with a pc-card slot
> should also support legacy PCI devices.
>
> If we get new architectures without I/O space in the future, they
> would certainly not care about supporting old cardbus devices.
POWER9 is another architecture with no port I/O space[1]:
Table 3-2. PCIe TLP command summary
-----------+-----------------------------+-------------------------------
Class | Type Name | Notes
===========+=============================+===============================
Completion | Completion without Data | For PCI CFG Writes (nonposted)
| | or for error responses.
Completion | Completion with Data | CI load responses.
Nonposted | Configuration Read Request | Outbound only.
Nonposted | Configuration Write Request | Outbound only.
Posted | Message Request | Inbound only.
Nonposted | Memory Read Request |
Posted | Memory Write Request |
===========+=============================+===============================
1. All other valid PCIe command types are ignored and dropped.
2. Invalid PCIe request command types will result in a completion
response of Unsupported Request.
------------------------------------+------------------------------------
that we do support -- I have such a system. And I guess POWER10 is the
same, as will be all future architecture updates.
References:
[1] "Power Systems Host Bridge 4 (PHB4) Specification", Version 1.0,
International Business Machines Corporation, 27 July 2018, Section 3.1
"PHB4 Command Details", p.29
Maciej
