Re: [PATCH] drivers: Let several drivers depends on HAS_IOMEM for 'devm_ioremap_resource'

Am 20.07.2014 10:38, schrieb Chen Gang:

On 07/19/2014 02:02 AM, Chen Gang wrote:

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2014-07-18 18:51 GMT+08:00 Richard Weinberger [off-list ref]:

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Am 18.07.2014 12:44, schrieb Chen Gang:

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On 07/18/2014 03:35 PM, Richard Weinberger wrote:

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Am 18.07.2014 02:36, schrieb Chen Gang:

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On 07/18/2014 02:09 AM, Richard Weinberger wrote:

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Am 17.07.2014 12:48, schrieb Arnd Bergmann:

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AFAICT, NO_IOMEM only has a real purpose on UML these days. Could we take
a shortcut here and make COMPILE_TEST depend on !UML? Getting random stuff
to build on UML seems pointless to me and we special-case it in a number of
places already.

If UML is the only arch without io memory the dependency on !UML seems
reasonable to me. :-)

For me, if only uml left, I suggest to implement dummy functions within
uml instead of let CONFIG_UML appear in generic include directory. And
then remove all HAS_IOMEM and NO_IOMEM from kernel.

Erm, this is something completely different.
I thought we're focusing on COMPILE_TEST?

COMPILE_TEST is none-architecture specific, but UML is. So in generic
include folder, if we're focusing on choosing whether COMPILE_TEST or
UML, for me, I will choose COMPILE_TEST.

If we're not only focusing on COMPILE_TEST, for me, if something only
depend on one architecture, I'd like to put them under "arch/*/" folder.

Especially, after that, we can remove all HAS_IOMEM and NO_IOMEM, nobody
has to think of them again. :-)

And then we end up with a solution that on UML a lot of completely useless
drivers are build which fail in various interesting manners because you'll
add stubs for all kinds of io memory related functions to arch/um/?
We had this kind of discussion already. You'll need more than ioremap...

I like Arnd's idea *much* more to make COMPILE_TEST depend on !UML.

That will let UML itself against COMPILE_TEST (but all the other
architectures not).

And if let COMPILE_TEST depend on !UML, can we still remove all
HAS_IOMEM and NO_IOMEM from kernel? (I guess so).

If we can remove them, we can send related patch firstly -- that will
let current discussion be in UML architecture wide instead of kernel
wide.

Next, I shall:

 - Remove HAS_IOMEM and NO_IOMEM from kernel, firstly.

This needs to be last, otherwise lot's of stuff will break.

 - Try to make dummy IOMEM functions for score architecture.

 - Continue discussing with UML for it.

If you find sane dummy functions for both UML and score I'm fine with it.

Thanks,
//richard