Subject: Re: [GIT PULL 1/2] asm-generic: rework PCI I/O space access
To:     Arnd Bergmann <arnd@kernel.org>
CC:     Niklas Schnelle <schnelle@linux.ibm.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-arch <linux-arch@vger.kernel.org>,
        linux-pci <linux-pci@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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From:   John Garry <john.garry@huawei.com>
Message-ID: <d45ee18a-1faa-9c56-071d-18f5737d225c@huawei.com>
Date:   Fri, 17 Dec 2021 16:30:15 +0000
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On 17/12/2021 15:55, Arnd Bergmann wrote:
>> > If you have a better way of finding the affected drivers,
>>   > that would be great.
>>
>> Assuming arm64 should select HAS_IOPORT, I am talking about f71805f as
>> an example. According to that patch, this driver additionally depends on
>> HAS_IOPORT; however I would rather arm64, like powerpc, should not allow
>> that driver to be built at all.
> Agreed, I missed these when I looked through the HAS_IOPORT users,
> that's why I suggested to split up that part of the patch per subsystem
> so they can be inspected more carefully.

ok

 >
 > My feeling is that in this case we want some other dependency, e.g. a
 > new CONFIG_LPC. It should actually be possible to use this driver on
 > any machine with an LPC bus, which would by definition be the primary
 > I/O space, so it should be possible to load it on Arm64.

You did suggest HARDCODED_IOPORT earlier in this thread, and the 
definition/premise there seemed sensible to me.

Anyway it seems practical to make all these changes in a single series, 
so need a way forward as Niklas has no such changes for this additional 
kconfig option.

As a start, may I suggest we at least have Niklas' patch committed to a 
dev branch based on -next or latest mainline release for further analysis?

Thanks,
John