Re: [PATCH 3/3] iommu: Enable compile testing for some of drivers

From: Krzysztof Kozlowski <krzk@kernel.org>
To: Suman Anna <s-anna@ti.com>
Cc: kbuild test robot <lkp@intel.com>,
	kbuild-all@lists.01.org, Joerg Roedel <joro@8bytes.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Eric Auger <eric.auger@redhat.com>,
	Douglas Anderson <dianders@chromium.org>,
	Tero Kristo <t-kristo@ti.com>,
	iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] iommu: Enable compile testing for some of drivers
Date: Fri, 3 Jan 2020 09:57:42 +0100	[thread overview]
Message-ID: <20200103081201.GA1439@pi3> (raw)
In-Reply-To: <923b1f2f-2b5c-8b6e-6083-243beae09777@ti.com>

On Thu, Jan 02, 2020 at 04:40:16PM -0600, Suman Anna wrote:
> Hi Krzysztof,
> 
> On 12/31/19 2:07 AM, Krzysztof Kozlowski wrote:
> > On Tue, Dec 31, 2019 at 03:43:39PM +0800, kbuild test robot wrote:
> >> Hi Krzysztof,
> >>
> >> I love your patch! Perhaps something to improve:
> >>
> >> [auto build test WARNING on iommu/next]
> >> [also build test WARNING on v5.5-rc4]
> >> [if your patch is applied to the wrong git tree, please drop us a note to help
> >> improve the system. BTW, we also suggest to use '--base' option to specify the
> >> base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
> >>
> >> url:    https://github.com/0day-ci/linux/commits/Krzysztof-Kozlowski/iommu-omap-Fix-pointer-cast-Wpointer-to-int-cast-warnings-on-64-bit/20191231-022212
> >> base:   https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git next
> >> config: ia64-allmodconfig (attached as .config)
> >> compiler: ia64-linux-gcc (GCC) 7.5.0
> >> reproduce:
> >>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> >>         chmod +x ~/bin/make.cross
> >>         # save the attached .config to linux build tree
> >>         GCC_VERSION=7.5.0 make.cross ARCH=ia64 
> >>
> >> If you fix the issue, kindly add following tag
> >> Reported-by: kbuild test robot <lkp@intel.com>
> > 
> > I saw it already while compile testing my patch. I must admit that I
> > could not find easy/fast fix for it.  Probably the
> > omap_iommu_translate() helper should be made 64-bit friendly but this
> > obfuscates the code. 
> 
> >The driver and hardware supports only 32-bit addresses.
> 
> Yeah, is there a reason why you are trying to enable the build for the
> OMAP IOMMU driver on 64-bit platforms or other architectures - the IP
> and driver is only ever used on ARMv7 platforms, and it should already
> be available for COMPILE_TEST on those.

It's the same reason we enable compile testing on all other drivers
which will never be used outside original platforms. There are many
of such examples because we want to increase the build coverage to as
many different configurations as possible. There could be also another
benefit - easier code reusability - although it is purely theoretical in
this case, I think.

Best regards,
Krzysztof