[PATCH v4] Kconfig: introduce HAS_IOPORT option and select it as necessary

Niklas Schnelle schnelle at linux.ibm.com
Thu Apr 6 01:12:38 AEST 2023

On Thu, 2023-03-23 at 17:33 +0100, Niklas Schnelle wrote:
> We introduce a new HAS_IOPORT Kconfig option to indicate support for I/O
> Port access. In a future patch HAS_IOPORT=n will disable compilation of
> the I/O accessor functions inb()/outb() and friends on architectures
> which can not meaningfully support legacy I/O spaces such as s390.
> The following architectures do not select HAS_IOPORT:
> * ARC
> * C-SKY
> * Hexagon
> * Nios II
> * OpenRISC
> * s390
> * User-Mode Linux
> * Xtensa
> All other architectures select HAS_IOPORT at least conditionally.
> The "depends on" relations on HAS_IOPORT in drivers as well as ifdefs
> for HAS_IOPORT specific sections will be added in subsequent patches on
> a per subsystem basis.
> Co-developed-by: Arnd Bergmann <arnd at kernel.org>
> Signed-off-by: Arnd Bergmann <arnd at kernel.org>
> Acked-by: Johannes Berg <johannes at sipsolutions.net> # for ARCH=um
> Acked-by: Geert Uytterhoeven <geert at linux-m68k.org>
> Signed-off-by: Niklas Schnelle <schnelle at linux.ibm.com>
> ---
> Note: This patch is the initial patch of a larger series[0]. This patch
> introduces the HAS_IOPORT config option while the rest of the series adds
> driver dependencies and the final patch removes inb() / outb() and friends on
> platforms that don't support them. 
> Thus each of the per-subsystem patches is independent from each other but
> depends on this patch while the final patch depends on the whole series. Thus
> splitting this initial patch off allows the per-subsytem HAS_IOPORT dependency
> addition be merged separately via different trees without breaking the build.
> [0] https://lore.kernel.org/lkml/20230314121216.413434-1-schnelle@linux.ibm.com/
> Changes since v3:
> - List archs without HAS_IOPORT in commit message (Arnd)
> - Select HAS_IOPORT for LoongArch (Arnd)
> - Use "select HAS_IOPORT if (E)ISA || .." instead of a "depends on" for (E)ISA
>   for m68k and parisc
> - Select HAS_IOPORT with config GSC on parisc (Arnd)
> - Drop "depends on HAS_IOPORT" for um's config ISA (Johannes)
> - Drop "depends on HAS_IOPORT" for config ISA on x86 and parisc where it is
>   always selected (Arnd)

Gentle ping. As far as I can tell this hasn't been picked to any tree
sp far but also hasn't seen complains so I'm wondering if I should send
a new version of the combined series of this patch plus the added
HAS_IOPORT dependencies per subsystem or wait until this is picked up.


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