On Wed, Nov 17, 2010 at 10:27:51AM +0100, Sam Ravnborg wrote: > On Tue, Nov 16, 2010 at 02:41:36PM -0800, dirk.brandewie@xxxxxxxxx wrote: > > From: Dirk Brandewie <dirk.brandewie@xxxxxxxxx> > > > > This patch adds support for linking device tree blobs into > > vmlinux. Modifies asm-generic/vmlinux.lds.h to add linking > > .dtb.init.rodata sections into the .init.data section of the vmlinux > > image. Modifies scripts/Makefile.lib to add a kbuild command to > > compile DTS files to device tree blobs and a rule to create objects to > > wrap the blobs for linking. > > > > The DTB's are placed on 32 byte boundries to allow parsing the blob > > with driver/of/fdt.c during early boot without having to copy the blob > > to get the structure alignment GCC expects. > > > > A DTB is linked in by adding the DTB object to the list of objects to > > be linked into vmlinux in the archtecture specific Makefile using > > obj-y += foo.dtb.o > > > > Signed-off-by: Dirk Brandewie <dirk.brandewie@xxxxxxxxx> > > --- > > include/asm-generic/vmlinux.lds.h | 19 +++++++++++++++++-- > > scripts/Makefile.lib | 20 ++++++++++++++++++++ > > 2 files changed, 37 insertions(+), 2 deletions(-) > > When you touch Makefiles in scripts/* it is always a good idea to cc: > kbuild maintainer on the patch - I have added Michal. > > Support functionality in Makefile.lib is documented in > Documentation/kbuild/* - please add documentation there. > > > > > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > > index bd69d79..ea671e7 100644 > > --- a/include/asm-generic/vmlinux.lds.h > > +++ b/include/asm-generic/vmlinux.lds.h > > @@ -67,7 +67,14 @@ > > * Align to a 32 byte boundary equal to the > > * alignment gcc 4.5 uses for a struct > > */ > > -#define STRUCT_ALIGN() . = ALIGN(32) > > +#define STRUCT_ALIGNMENT 32 > > +#define STRUCT_ALIGN() . = ALIGN(STRUCT_ALIGNMENT) > > + > > +/* Device tree blobs linked into the kernel need to have proper > > + * structure alignment to be parsed by the flat device tree library > > + * used in early boot > > +*/ > > +#define DTB_ALIGNMENT STRUCT_ALIGNMENT > > It has been discussed in another thread some time ago to move > to a general 32 byte alignment for everything in vmlinux.lds.h > So there is not much need for the specific DTB alignment. > > > diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib > > index 4c72c11..29db062 100644 > > --- a/scripts/Makefile.lib > > +++ b/scripts/Makefile.lib > > @@ -200,6 +200,26 @@ quiet_cmd_gzip = GZIP $@ > > cmd_gzip = (cat $(filter-out FORCE,$^) | gzip -f -9 > $@) || \ > > (rm -f $@ ; false) > > > > +# DTC > > +# --------------------------------------------------------------------------- > > +$(obj)/%.dtb.S: $(obj)/%.dtb FORCE > > + @echo '#include <asm-generic/vmlinux.lds.h>' > $@ > > + @echo '.section .dtb.init.rodata,"a"' >> $@ > > + @echo '.balign DTB_ALIGNMENT' >> $@ > > + @echo '.global __dtb_$(*F)_begin' >> $@ > > + @echo '__dtb_$(*F)_begin:' >> $@ > > + @echo '.incbin "$<" ' >> $@ > > + @echo '__dtb_$(*F)_end:' >> $@ > > + @echo '.global __dtb_$(*F)_end' >> $@ > > + @echo '.balign DTB_ALIGNMENT' >> $@ > > > This will be noisy during build. Please use proper macors to supress output. > > > > + > > +DTC = $(objtree)/scripts/dtc/dtc > > + > > +quiet_cmd_dtc = DTC $@ > Please avoid tabs in the output - all other uses spaces. (There is a tab between DTC and $@) > > > + cmd_dtc = $(DTC) -O dtb -o $(obj)/$*.dtb -b 0 $(DTS_FLAGS) $(src)/dts/$*.dts > > Looks strange. How about: > cmd_dtc = $(DTC) -O dtb -o $@ -b 0 $(DTS_FLAGS) $< > > Then you avoid the hardcoded path in the rule too. > > > > + > > +$(obj)/%.dtb: $(src)/dts/%.dts > > + $(call if_changed,dtc) The rule should be generic (not depend on the presence of a dts subdirectory. Basically, the .dtb really should be generated in the same directory as the .dts file. There is no reason for this rule to have special behaviour. > > This snippet belong in the file that uses this. > This is how we do for other rules like bzip etc. This rule is intended to be generic and usable anywhere in the tree. g. -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
