On Tue, 16 Dec 2014 15:13:24 +1300 , Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx> wrote: > Currently in arch and driver code that needs early access to the > flattened device tree it is necessary to add specific CFLAGS so that > when scripts/dtc/libfdt/libfdt.h is included the C preprocessor is able > to locate the libfdt versions of libfdt_env.h and fdt.h without > generating an error. > > We already provide an alternative linux-specific > version of libfdt_env.h and directly include scripts/dtc/libfdt/fdt.h > so the inclusion by scripts/dtc/libfdt/libfdt.h is a no-op thanks to the > inclusion guards. > > By using quotes in scripts/dtc/libfdt/libfdt.h it picks up fdt.h and > libfdt_env.h from the source directory without needing to add CFLAGS for > the sources that happen to include linux/libfdt.h. > > Signed-off-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx> > --- > Hi, > > This probably should come via git://git.jdl.com/software/dtc.git however > this appears to be inaccessible at the moment. Is this still the > canonical source for the device tree compiler and libfdt or has it been > moved? How much deviation from the canonical source are we prepared to > live with in the kernel? > > This came up on the arm-LKML[1]. Basically in the name of backwards > compatibility I need to add a .dt_fixup to add some required nodes to > the flattened device tree prior to the tree being un-flattened and > processed. This is a trick powerpc makes use of fairly extensively and > there are a few other instances of this. > > For the files that include linux/libfdt.h we currently also have to > specify additional CFLAGS to satisfy the CPP. > > $ git grep '<linux/libfdt.h>' > arch/mips/cavium-octeon/octeon-platform.c:#include <linux/libfdt.h> > arch/mips/cavium-octeon/setup.c:#include <linux/libfdt.h> > arch/mips/mti-sead3/sead3-setup.c:#include <linux/libfdt.h> > arch/powerpc/kernel/prom.c:#include <linux/libfdt.h> > drivers/firmware/efi/libstub/fdt.c:#include <linux/libfdt.h> > drivers/of/fdt.c:#include <linux/libfdt.h> > drivers/of/fdt_address.c:#include <linux/libfdt.h> > > $ git grep -e '-I.*dtc/libfdt' > arch/mips/cavium-octeon/Makefile:CFLAGS_octeon-platform.o = -I$(src)/../../../scripts/dtc/libfdt > arch/mips/cavium-octeon/Makefile:CFLAGS_setup.o = -I$(src)/../../../scripts/dtc/libfdt > arch/mips/mti-sead3/Makefile:CFLAGS_sead3-setup.o = -I$(src)/../../../scripts/dtc/libfdt > arch/powerpc/kernel/Makefile:CFLAGS_prom.o = -I$(src)/../../../scripts/dtc/libfdt > drivers/firmware/efi/libstub/Makefile:CFLAGS_fdt.o += -I$(srctree)/scripts/dtc/libfdt/ > drivers/of/Makefile:CFLAGS_fdt.o = -I$(src)/../../scripts/dtc/libfdt > drivers/of/Makefile:CFLAGS_fdt_address.o = -I$(src)/../../scripts/dtc/libfdt > lib/Makefile: $(eval CFLAGS_$(file) = -I$(src)/../scripts/dtc/libfdt)) > > Simply by switching to using quotes we can avoid having this extra step. > > Assuming that this patch is acceptable a follow on clean up would be to > remove the instances of CFLAGS_... listed above. > > Regards, > Chris > -- > [1] - http://lists.infradead.org/pipermail/linux-arm-kernel/2014-December/310840.html > > scripts/dtc/libfdt/libfdt.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/scripts/dtc/libfdt/libfdt.h b/scripts/dtc/libfdt/libfdt.h > index 73f4975..ea1ddcd 100644 > --- a/scripts/dtc/libfdt/libfdt.h > +++ b/scripts/dtc/libfdt/libfdt.h > @@ -51,8 +51,8 @@ > * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. > */ > > -#include <libfdt_env.h> > -#include <fdt.h> > +#include "libfdt_env.h" > +#include "fdt.h" Until this is resolved with upstream DTC, what about adding dummy libfdt.h, libfdt_env.h and fdt.h to include/linux? That would get this out of the blocker path for merging this code. g. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
