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

Thierry Reding
2014-07-17T09:51:32Z

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On Thu, Jul 17, 2014 at 05:29:31PM +0800, Chen Gang wrote:
>
>
> On 07/17/2014 05:20 PM, Arnd Bergmann wrote:
> > On Thursday 17 July 2014 09:27:58 Chen Gang wrote:
> >> gfp_t gfp_mask, unsigned int order);
> >> extern void devm_free_pages(struct device *dev, unsigned long addr);
> >>
> >> +#ifdef CONFIG_HAS_IOMEM
> >> void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res);
> >> +#elif defined(CONFIG_COMPILE_TEST)
> >> +static inline void __iomem *devm_ioremap_resource(struct device *dev,
> >> + struct resource *res)
> >> +{
> >> + pr_warn("no hardware io memory, only for COMPILE_TEST\n");
> >> + return (__force void __iomem *)ERR_PTR(-ENXIO);
> >> +}
> >> +#endif /* CONFIG_HAS_IOMEM || CONFIG_COMPILE_TEST */
> >>
> >> /* allows to add/remove a custom action to devres stack */
> >
> > To be honest, I think it's a bad idea to introduce wrappers functions
> > that are only available when CONFIG_COMPILE_TEST is set.
> >
> > COMPILE_TEST is a great tool in general, but it has its limits.
> > In particular, the case for !CONFIG_IOMEM is completely obscure
> > and we won't find any bugs by allowing more drivers to be built
> > in those configurations, but attempting to do it would cause
> > endless churn by changing each instance of 'depends on HAS_IOMEM'
> > to 'depends on HAS_IOMEM || COMPILE_TEST'.
> >
>
> Architecture members and driver members really have different tastes,
> they are different roles. It really need additional discussion.
>
> For me, I only want to change devm_io*map*, not touch so much.
>
> Welcome any other members' idea or suggestions.
>
> > Note that s390 no has gained support for IOMEM, tile has it most
> > of the time (when PCI is enabled, so you get it in half the
> > test builds already), score should set HAS_IOMEM and doesn't
> > even have public compilers, and uml doesn't even compile in
> > latest mainline. Nothing else ever sets NO_IOMEM.
> >
>
> In latest gcc and binutils, can compile score cross compiler
> successfully for building kernel (but I am not quite sure whether the
> compiling result are really OK, but I guess so).

I was only able to ever build a partial bare-metal toolchain for score.
There's no uClibc, glibc or newlib support, so it becomes rather useless
as a Linux architecture.

Also when I run the cross-compiler on a score defconfig build, I get a
bunch of these:

score-unknown-elf-gcc-4.9.0: internal compiler error: Segmentation fault (program as)

Thierry

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