linux-kernel - Re: [PATCH] pinctrl: zynq: Use define directive for PIN_CONFIG_IO

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Message-ID: <20181109153626.GA6494@flashbox>
Date:   Fri, 9 Nov 2018 08:36:26 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Michal Simek <michal.simek@...inx.com>
Cc:     Nick Desaulniers <ndesaulniers@...gle.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-gpio@...r.kernel.org,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] pinctrl: zynq: Use define directive for
 PIN_CONFIG_IO_STANDARD

On Fri, Nov 09, 2018 at 10:33:00AM +0100, Michal Simek wrote:
> On 08. 11. 18 16:01, Nathan Chancellor wrote:
> > On Thu, Nov 08, 2018 at 07:45:42AM +0100, Michal Simek wrote:
> >> On 07. 11. 18 18:48, Nick Desaulniers wrote:
> >>> On Wed, Nov 7, 2018 at 1:01 AM Michal Simek <michal.simek@...inx.com> wrote:
> >>>>
> >>>> On 07. 11. 18 9:55, Nathan Chancellor wrote:
> >>>>> On Wed, Nov 07, 2018 at 09:46:12AM +0100, Michal Simek wrote:
> >>>>>> On 01. 11. 18 1:57, Nathan Chancellor wrote:
> >>>>>>> Clang warns when one enumerated type is implicitly converted to another:
> >>>>>>>
> >>>>>>> drivers/pinctrl/pinctrl-zynq.c:985:18: warning: implicit conversion from
> >>>>>>> enumeration type 'enum zynq_pin_config_param' to different enumeration
> >>>>>>> type 'enum pin_config_param' [-Wenum-conversion]
> >>>>>>>         {"io-standard", PIN_CONFIG_IOSTANDARD, zynq_iostd_lvcmos18},
> >>>>>>>         ~               ^~~~~~~~~~~~~~~~~~~~~
> >>>>>>> drivers/pinctrl/pinctrl-zynq.c:990:16: warning: implicit conversion from
> >>>>>>> enumeration type 'enum zynq_pin_config_param' to different enumeration
> >>>>>>> type 'enum pin_config_param' [-Wenum-conversion]
> >>>>>>>         = { PCONFDUMP(PIN_CONFIG_IOSTANDARD, "IO-standard", NULL, true),
> >>>>>>>             ~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >>>>>>> ./include/linux/pinctrl/pinconf-generic.h:163:11: note: expanded from
> >>>>>>> macro 'PCONFDUMP'
> >>>>>>>         .param = a, .display = b, .format = c, .has_arg = d     \
> >>>>>>>                  ^
> >>>>>>> 2 warnings generated.
> >>>>>>
> >>>>>> This is interesting. I have never tried to use llvm for building the
> >>>>>> kernel. Do you have any description how this can be done?
> >>>>>>
> >>>>>
> >>>>> Depending on what version of Clang you have access to, it is usually just as
> >>>>> simple as running 'make ARCH=arm CC=clang CROSS_COMPILE=arm-linux-gnueabi-'.
> >>>>>
> >>>>> Clang 7.0+ is recommended but 6.0 might work too.
> >>>>
> >>>> TBH I would expect to download container and run this there to make sure
> >>>> that I don't break anything else.
> >>>
> >>> This is the first request we've had for a container in order to test a
> >>> patch.  If it comes up again from other folks, I think it makes sense
> >>> to create one.  Until then, its nice to have.  It's definitely
> >>> overkill for this patch.
> >>
> >> I have played with it to see that error and here are some steps I did.
> >>
> >> docker run --name test-clang -it --rm debian:latest bash
> >> apt-get update
> >> apt-get install gcc-arm-linux-gnueabi gcc-aarch64-linux-gnu clang git bc
> >> build-essential bison flex make llvm vim libssl-dev sparse
> >>
> >> git clone
> >> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git --depth 1
> >> cd linux
> >>
> >> export ARCH=arm64
> >> export CROSS_COMPILE=aarch64-linux-gnu-
> >>
> >> make defconfig
> > 
> > This should also have 'CC=clang' because compiler detection happens in
> > Kconfig now so compiler flags get properly set. Other than that, looks
> > good and I was able to build pinctrl-zynq.o without any issues with
> > those commands.
> 
> For arm32 I am still getting compilation issue (arm64 is fine)
> Below are my steps and version I use. Do you know what could be the
> problem?
> 
> Thanks,
> Michal
> 
> root@...5921e6d15:~/linux# arm-linux-gnueabi-gcc --version
> arm-linux-gnueabi-gcc (Debian 6.3.0-18) 6.3.0 20170516
> Copyright (C) 2016 Free Software Foundation, Inc.
> This is free software; see the source for copying conditions.  There is NO
> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> 
> root@...5921e6d15:~/linux# clang --version
> clang version 3.8.1-24 (tags/RELEASE_381/final)
> Target: x86_64-pc-linux-gnu
> Thread model: posix
> InstalledDir: /usr/bin
> 
> 
> export ARCH=arm
> export CROSS_COMPILE=arm-linux-gnuaebi-
> make CC=clang defconfig
> make CC=clang drivers/pinctrl/pinctrl-zynq.o
> 
> and I get
> clang: error: unsupported argument '-W' to option 'Wa,'
> scripts/Makefile.build:305: recipe for target 'scripts/mod/empty.o' failed
> make[2]: *** [scripts/mod/empty.o] Error 1
> scripts/Makefile.build:546: recipe for target 'scripts/mod' failed
> 

Ah because Debian's regular Clang is ancient.

For testing, we use the builds from apt.llvm.org. Commands assuming
you're using the normal Debian image:

curl https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add -
echo "deb http://apt.llvm.org/stretch/ llvm-toolchain-stretch main" | tee -a /etc/apt/sources.list
apt-get update -qq && apt-get install -y clang-8

Then use `CC=clang-8' instead of 'CC=clang' for all make invocations.

Let me know if there are any more issues!
Nathan