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SubjectRe: [RFC v2 25/39] pcmcia: add HAS_IOPORT dependencies
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

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