[PATCH] iio: adc: Specify IOMEM dependency for adi-axi-adc driver

[PATCH] iio: adc: Specify IOMEM dependency for adi-axi-adc driver

[David Gow]

The Analog Devices AXI ADC driver uses the devm_ioremap_resource
function, but does not specify a dependency on IOMEM in Kconfig. This
causes a build failure on architectures without IOMEM, for example, UML
(notably with make allyesconfig).

Fix this by making CONFIG_ADI_AXI_ADC depend on CONFIG_IOMEM.

Signed-off-by: David Gow <davidgow@google.com>
---
 drivers/iio/adc/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index ff3569635ce0..f5009b61b80c 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -263,6 +263,7 @@ config AD9467
 
 config ADI_AXI_ADC
 	tristate "Analog Devices Generic AXI ADC IP core driver"
+	depends on IOMEM
 	select IIO_BUFFER
 	select IIO_BUFFER_HW_CONSUMER
 	select IIO_BUFFER_DMAENGINE
-- 
2.27.0.212.ge8ba1cc988-goog

Re: [PATCH] iio: adc: Specify IOMEM dependency for adi-axi-adc driver

[Jonathan Cameron]

On Tue, 30 Jun 2020 00:05:52 -0700
David Gow <davidgow@google.com> wrote:

> The Analog Devices AXI ADC driver uses the devm_ioremap_resource
> function, but does not specify a dependency on IOMEM in Kconfig. This
> causes a build failure on architectures without IOMEM, for example, UML
> (notably with make allyesconfig).
> 
> Fix this by making CONFIG_ADI_AXI_ADC depend on CONFIG_IOMEM.
> 
> Signed-off-by: David Gow <davidgow@google.com>
Hi David,

Could you confirm what the build error is?  I thought the stubs added in
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1bcbfbfdeb
were meant to allow us to avoid having lots of depends on IOMEM lines for the
few architectures who don't support it.

Jonathan

> ---
>  drivers/iio/adc/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index ff3569635ce0..f5009b61b80c 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -263,6 +263,7 @@ config AD9467
>  
>  config ADI_AXI_ADC
>  	tristate "Analog Devices Generic AXI ADC IP core driver"
> +	depends on IOMEM
>  	select IIO_BUFFER
>  	select IIO_BUFFER_HW_CONSUMER
>  	select IIO_BUFFER_DMAENGINE

Re: [PATCH] iio: adc: Specify IOMEM dependency for adi-axi-adc driver

[David Gow]

On Tue, Jun 30, 2020 at 6:07 PM Jonathan Cameron
<Jonathan.Cameron@huawei.com> wrote:
>
> On Tue, 30 Jun 2020 00:05:52 -0700
> David Gow <davidgow@google.com> wrote:
>
> > The Analog Devices AXI ADC driver uses the devm_ioremap_resource
> > function, but does not specify a dependency on IOMEM in Kconfig. This
> > causes a build failure on architectures without IOMEM, for example, UML
> > (notably with make allyesconfig).
> >
> > Fix this by making CONFIG_ADI_AXI_ADC depend on CONFIG_IOMEM.
> >
> > Signed-off-by: David Gow <davidgow@google.com>
> Hi David,
>
> Could you confirm what the build error is?  I thought the stubs added in
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1bcbfbfdeb
> were meant to allow us to avoid having lots of depends on IOMEM lines for the
> few architectures who don't support it.

No worries:
/usr/bin/ld: drivers/iio/adc/adi-axi-adc.o: in function `adi_axi_adc_probe':
torvalds-linux/drivers/iio/adc/adi-axi-adc.c:415: undefined reference
to `devm_platform_ioremap_resource'

Alas, the devm_platform_ioremap_resource function isn't handled by the
UML stubs: it all seems to be in drivers/base/platform.c and
lib/devres.c, behind #ifdef HAS_IOMEM.

In any case, improving IOMEM support for UML (at least for the KUnit
test case, which is my use case) is something I'd like to do. There
are only three drivers[1,2] upstream at the moment which fail to build
as-is, though, so it seemed worth trying to fix them in the meantime.
That being said, I tried just getting rid of the few #ifdef HAS_IOMEMs
around the various devm_*_ioremap functions, and everything seems to
be working... So maybe that's a false dependency given the various
stubs (at least on UML). I used this (hideously hacky) patch:

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index c0d0a5490ac6..b6f08c88e2b6 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -61,7 +61,7 @@ struct resource *platform_get_resource(struct
platform_device *dev,
}
EXPORT_SYMBOL_GPL(platform_get_resource);

-#ifdef CONFIG_HAS_IOMEM
+#if 1//def CONFIG_HAS_IOMEM
/**
 * devm_platform_get_and_ioremap_resource - call devm_ioremap_resource() for a
 *                                         platform device and get resource
diff --git a/lib/Makefile b/lib/Makefile
index b1c42c10073b..35c21af33b93 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -115,7 +115,7 @@ obj-y += math/ crypto/

obj-$(CONFIG_GENERIC_IOMAP) += iomap.o
obj-$(CONFIG_GENERIC_PCI_IOMAP) += pci_iomap.o
-obj-$(CONFIG_HAS_IOMEM) += iomap_copy.o devres.o
+obj-y += iomap_copy.o devres.o
obj-$(CONFIG_CHECK_SIGNATURE) += check_signature.o
obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o

---

If this seems to work more broadly, I may try to clean it up and post
it for broader review.

Cheers,
-- David

Re: [PATCH] iio: adc: Specify IOMEM dependency for adi-axi-adc driver

[Jonathan Cameron]

On Wed, 1 Jul 2020 11:04:42 +0800
David Gow <davidgow@google.com> wrote:

> On Tue, Jun 30, 2020 at 6:07 PM Jonathan Cameron
> <Jonathan.Cameron@huawei.com> wrote:
> >
> > On Tue, 30 Jun 2020 00:05:52 -0700
> > David Gow <davidgow@google.com> wrote:
> >  
> > > The Analog Devices AXI ADC driver uses the devm_ioremap_resource
> > > function, but does not specify a dependency on IOMEM in Kconfig. This
> > > causes a build failure on architectures without IOMEM, for example, UML
> > > (notably with make allyesconfig).
> > >
> > > Fix this by making CONFIG_ADI_AXI_ADC depend on CONFIG_IOMEM.
> > >
> > > Signed-off-by: David Gow <davidgow@google.com>  
> > Hi David,
> >
> > Could you confirm what the build error is?  I thought the stubs added in
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1bcbfbfdeb
> > were meant to allow us to avoid having lots of depends on IOMEM lines for the
> > few architectures who don't support it.  
> 
> No worries:
> /usr/bin/ld: drivers/iio/adc/adi-axi-adc.o: in function `adi_axi_adc_probe':
> torvalds-linux/drivers/iio/adc/adi-axi-adc.c:415: undefined reference
> to `devm_platform_ioremap_resource'
> 
> Alas, the devm_platform_ioremap_resource function isn't handled by the
> UML stubs: it all seems to be in drivers/base/platform.c and
> lib/devres.c, behind #ifdef HAS_IOMEM.
> 
> In any case, improving IOMEM support for UML (at least for the KUnit
> test case, which is my use case) is something I'd like to do. There
> are only three drivers[1,2] upstream at the moment which fail to build
> as-is, though, so it seemed worth trying to fix them in the meantime.
> That being said, I tried just getting rid of the few #ifdef HAS_IOMEMs
> around the various devm_*_ioremap functions, and everything seems to
> be working... So maybe that's a false dependency given the various
> stubs (at least on UML). I used this (hideously hacky) patch:
> 
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index c0d0a5490ac6..b6f08c88e2b6 100644
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -61,7 +61,7 @@ struct resource *platform_get_resource(struct
> platform_device *dev,
> }
> EXPORT_SYMBOL_GPL(platform_get_resource);
> 
> -#ifdef CONFIG_HAS_IOMEM
> +#if 1//def CONFIG_HAS_IOMEM
> /**
>  * devm_platform_get_and_ioremap_resource - call devm_ioremap_resource() for a
>  *                                         platform device and get resource
> diff --git a/lib/Makefile b/lib/Makefile
> index b1c42c10073b..35c21af33b93 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -115,7 +115,7 @@ obj-y += math/ crypto/
> 
> obj-$(CONFIG_GENERIC_IOMAP) += iomap.o
> obj-$(CONFIG_GENERIC_PCI_IOMAP) += pci_iomap.o
> -obj-$(CONFIG_HAS_IOMEM) += iomap_copy.o devres.o
> +obj-y += iomap_copy.o devres.o
> obj-$(CONFIG_CHECK_SIGNATURE) += check_signature.o
> obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o
> 
> ---
> 
> If this seems to work more broadly, I may try to clean it up and post
> it for broader review.

Looks like a good approach to me!

Jonathan

> 
> Cheers,
> -- David