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

Richard Weinberger
2014-07-17T09:26:57Z

Am 17.07.2014 11:20, schrieb Arnd Bergmann:
> 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'.
>
> 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.

Huh? UML (v3.16-rc5-143-gb6603fe) builds fine here. What build issue are you facing?

Thanks,
//richard