On Wed, Dec 22, 2010 at 11:57:26AM -0800, dirk.brandewie@xxxxxxxxx wrote: > From: Dirk Brandewie <dirk.brandewie@xxxxxxxxx> > > This patch adds support for linking device tree blob(s) into > vmlinux. Modifies asm-generic/vmlinux.lds.h to add linking > .dtb sections into vmlinux. To maintain compatiblity with the of/fdt > driver code platforms MUST copy the blob to a non-init memory location > before the kernel frees the .init.* sections in the 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. > > STRUCT_ALIGNMENT is defined in vmlinux.lds.h for use in the rule to > create wrapper objects for the dtb in Makefile.lib. The > STRUCT_ALIGN() macro in vmlinux.lds.h is modified to use the > STRUCT_ALIGNMENT definition. > > 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> merged, thanks. g. > --- > Documentation/kbuild/makefiles.txt | 15 +++++++++++++++ > include/asm-generic/vmlinux.lds.h | 13 +++++++++++-- > scripts/Makefile.lib | 23 +++++++++++++++++++++++ > 3 files changed, 49 insertions(+), 2 deletions(-) > > diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt > index 0ef00bd..86e3cd0 100644 > --- a/Documentation/kbuild/makefiles.txt > +++ b/Documentation/kbuild/makefiles.txt > @@ -1136,6 +1136,21 @@ When kbuild executes, the following steps are followed (roughly): > resulting in the target file being recompiled for no > obvious reason. > > + dtc > + Create flattend device tree blob object suitable for linking > + into vmlinux. Device tree blobs linked into vmlinux are placed > + in an init section in the image. Platform code *must* copy the > + blob to non-init memory prior to calling unflatten_device_tree(). > + > + Example: > + #arch/x86/platform/ce4100/Makefile > + clean-files := *dtb.S > + > + DTC_FLAGS := -p 1024 > + obj-y += foo.dtb.o > + > + $(obj)/%.dtb: $(src)/%.dts > + $(call cmd,dtc) > > --- 6.7 Custom kbuild commands > > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > index bd69d79..05cbad0 100644 > --- a/include/asm-generic/vmlinux.lds.h > +++ b/include/asm-generic/vmlinux.lds.h > @@ -67,7 +67,8 @@ > * 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) > > /* The actual configuration determine if the init/exit sections > * are handled as text/data or they can be discarded (which > @@ -146,6 +147,13 @@ > #define TRACE_SYSCALLS() > #endif > > + > +#define KERNEL_DTB() \ > + STRUCT_ALIGN(); \ > + VMLINUX_SYMBOL(__dtb_start) = .; \ > + *(.dtb.init.rodata) \ > + VMLINUX_SYMBOL(__dtb_end) = .; > + > /* .data section */ > #define DATA_DATA \ > *(.data) \ > @@ -468,7 +476,8 @@ > MCOUNT_REC() \ > DEV_DISCARD(init.rodata) \ > CPU_DISCARD(init.rodata) \ > - MEM_DISCARD(init.rodata) > + MEM_DISCARD(init.rodata) \ > + KERNEL_DTB() > > #define INIT_TEXT \ > *(.init.text) \ > diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib > index 4c72c11..7df8eb5 100644 > --- a/scripts/Makefile.lib > +++ b/scripts/Makefile.lib > @@ -200,6 +200,29 @@ quiet_cmd_gzip = GZIP $@ > cmd_gzip = (cat $(filter-out FORCE,$^) | gzip -f -9 > $@) || \ > (rm -f $@ ; false) > > +# DTC > +# --------------------------------------------------------------------------- > + > +# Generate an assembly file to wrap the output of the device tree compiler > +quiet_cmd_dt_S_dtb= DTB $@ > +cmd_dt_S_dtb= \ > +( \ > + echo '\#include <asm-generic/vmlinux.lds.h>'; \ > + echo '.section .dtb.init.rodata,"a"'; \ > + echo '.balign STRUCT_ALIGNMENT'; \ > + echo '.global __dtb_$(*F)_begin'; \ > + echo '__dtb_$(*F)_begin:'; \ > + echo '.incbin "$<" '; \ > + echo '__dtb_$(*F)_end:'; \ > + echo '.global __dtb_$(*F)_end'; \ > + echo '.balign STRUCT_ALIGNMENT'; \ > +) > $@ > + > +$(obj)/%.dtb.S: $(obj)/%.dtb > + $(call cmd,dt_S_dtb) > + > +quiet_cmd_dtc = DTC $@ > + cmd_dtc = $(objtree)/scripts/dtc/dtc -O dtb -o $@ -b 0 $(DTC_FLAGS) $< > > # Bzip2 > # --------------------------------------------------------------------------- > -- > 1.7.2.3 > > _______________________________________________ > devicetree-discuss mailing list > devicetree-discuss@xxxxxxxxxxxxxxxx > https://lists.ozlabs.org/listinfo/devicetree-discuss -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
