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(-) 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 /* The actual configuration determine if the init/exit sections * are handled as text/data or they can be discarded (which @@ -146,6 +153,13 @@ #define TRACE_SYSCALLS() #endif + +#define KERNEL_DTB() \ + . = ALIGN(DTB_ALIGNMENT); \ + VMLINUX_SYMBOL(__dtb_start) = .; \ + *(.dtb.init.rodata) \ + VMLINUX_SYMBOL(__dtb_end) = .; + /* .data section */ #define DATA_DATA \ *(.data) \ @@ -468,7 +482,8 @@ 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..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' >> $@ + +DTC = $(objtree)/scripts/dtc/dtc + +quiet_cmd_dtc = DTC $@ + cmd_dtc = $(DTC) -O dtb -o $(obj)/$*.dtb -b 0 $(DTS_FLAGS) $(src)/dts/$*.dts + +$(obj)/%.dtb: $(src)/dts/%.dts + $(call if_changed,dtc) # Bzip2 # --------------------------------------------------------------------------- -- 1.7.2.3 -- 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
