Re: [PATCH v4 10/19] Introduce asm-generic/*.h files

[Christoffer Dall <christoffer.dall@linaro.org>]

On Mon, Jun 09, 2014 at 10:23:27AM +0200, Andrew Jones wrote:
> On Fri, Jun 06, 2014 at 08:39:09PM +0200, Christoffer Dall wrote:
> > On Thu, Apr 10, 2014 at 06:56:51PM +0200, Andrew Jones wrote:
> > > Architecture neutral code may need to call low-level io accessors,
> > > or use spinlocks. Create a generic io.h to ensure those accessors
> > > are defined, and a generic spinlock.h that complains when included,
> > > as we can't write a generic spinlock. These files can be overridden
> > > or extended by architecture specific versions placed in
> > > lib/$ARCH/asm/.
> > > 
> > > Signed-off-by: Andrew Jones <drjones@redhat.com>
> > > ---
> > > v4: introduce lib/asm symlink to get rid of #ifdef __arm__,
> > >     add spinlock.h too
> > > v3: wrt to io.h (was libio.[ch]) only
> > >     - get rid of CONFIG_64BIT, replace with asserts
> > >     - get rid of {read,write}_len() [libio.c]
> > >     - fix bad *64_to_cpu macros
> > > ---
> > >  .gitignore                 |   1 +
> > >  Makefile                   |   6 +-
> > >  configure                  |  11 ++++
> > >  lib/asm-generic/io.h       | 154 +++++++++++++++++++++++++++++++++++++++++++++
> > >  lib/asm-generic/spinlock.h |   4 ++
> > >  5 files changed, 173 insertions(+), 3 deletions(-)
> > >  create mode 100644 lib/asm-generic/io.h
> > >  create mode 100644 lib/asm-generic/spinlock.h
> > > 
> > > diff --git a/.gitignore b/.gitignore
> > > index 775d0dfd8263e..e21939a8771e9 100644
> > > --- a/.gitignore
> > > +++ b/.gitignore
> > > @@ -9,6 +9,7 @@ patches
> > >  .stgit-*
> > >  cscope.*
> > >  *.swp
> > > +/lib/asm
> > >  /config.mak
> > >  /*-run
> > >  /test.log
> > > diff --git a/Makefile b/Makefile
> > > index fba58e36f272f..51cacdac00615 100644
> > > --- a/Makefile
> > > +++ b/Makefile
> > > @@ -76,11 +76,11 @@ libfdt_clean:
> > >  	$(LIBFDT_objdir)/.*.d
> > >  
> > >  distclean: clean libfdt_clean
> > > -	$(RM) config.mak $(TEST_DIR)-run test.log msr.out cscope.*
> > > +	$(RM) lib/asm config.mak $(TEST_DIR)-run test.log msr.out cscope.*
> > >  
> > > -cscope: common_dirs = lib lib/libfdt
> > > +cscope: common_dirs = lib lib/libfdt lib/asm lib/asm-generic
> > >  cscope:
> > >  	$(RM) ./cscope.*
> > > -	find $(TEST_DIR) lib/$(TEST_DIR) $(common_dirs) -maxdepth 1 \
> > > +	find -L $(TEST_DIR) lib/$(TEST_DIR) $(common_dirs) -maxdepth 1 \
> > >  		-name '*.[chsS]' -print | sed 's,^\./,,' > ./cscope.files
> > >  	cscope -bk
> > > diff --git a/configure b/configure
> > > index 6cfc64943f6e6..8a81bf92e27b7 100755
> > > --- a/configure
> > > +++ b/configure
> > > @@ -95,6 +95,17 @@ if [ $exit -eq 0 ]; then
> > >  fi
> > >  rm -f lib_test.c
> > >  
> > > +# link lib/asm for the architecture
> > > +rm -f lib/asm
> > > +asm=asm-generic
> > > +if [ -d lib/$arch/asm ]; then
> > > +	asm=$arch/asm
> > > +elif [ -d lib/$testdir/asm ]; then
> > > +	asm=$testdir/asm
> > 
> > why do you need this elif?  can you not make sure arch is always set?
> 
> arch is always set, but there's a chance some arch may not add it's own
> lib/$arch dir. It's a pretty small chance... but the elif shouldn't hurt.
> 
If we don't have any code that uses this scheme now then let's now have
Makefile rules that encourages non-standard behavior (unless I'm missing
the point and this provides a 'feature' for specific archs or something
like that).

-Christoffer