On 07/17/2014 11:20 AM, 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'.
The point of this exercise is that we do not have to replace a good chunk of
'depends on COMPILE_TEST' with 'depends on COMPILE_TEST && HAS_IOMEM'
E.g. the typical Kconfig entry for your random SoC peripheral driver looks like
config ARCH_FOOBAR_DRIVER
depends on ARCH_FOOBAR || COMPILE_TEST
...
Now when COMPILE_TEST is not set there is a implicit dependency on HAS_IOMEM
since the architecture will provide it. If COMPILE_TEST is selected the
driver will also be build-able on architectures that do no have HAS_IOMEM
and hence linking the driver fails. One way to fix this is of course to
replace the COMPILE_TEST with (COMPILE_TEST && HAS_IOMEM). But this is very
often overlooked and only noticed later on when somebody actually builds a
allyesconfig on an architecture that does not provide HAS_IOMEM. To avoid
these kinds of build errors and tedious fixup patches the idea is to provide
a stub function when HAS_IOMEM is not enabled, but COMPILE_TEST is enabled.
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