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

[Maciej W. Rozycki]

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