diff options
author | Dirk Brandewie <dirk.brandewie@gmail.com> | 2010-12-22 11:57:26 -0800 |
---|---|---|
committer | Grant Likely <grant.likely@secretlab.ca> | 2010-12-23 14:43:00 -0700 |
commit | aab94339cd85d726abeae78fc02351fc1910e6a4 (patch) | |
tree | 25d434a1dec4f758a9938e621dc1516f7a788521 | |
parent | cfb13c5db08c90311a5defdde9a0328ee788cca5 (diff) |
of: Add support for linking device tree blobs into vmlinux
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@gmail.com>
Acked-by: Michal Marek <mmarek@suse.cz>
[grant.likely@secretlab.ca: cleaned up whitespace inconsistencies]
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
-rw-r--r-- | Documentation/kbuild/makefiles.txt | 15 | ||||
-rw-r--r-- | include/asm-generic/vmlinux.lds.h | 13 | ||||
-rw-r--r-- | scripts/Makefile.lib | 23 |
3 files changed, 49 insertions, 2 deletions
diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index 0ef00bd6e54..86e3cd0d26a 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 bd69d79208d..05cbad03c5a 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 4c72c118947..396da16aabf 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 # --------------------------------------------------------------------------- |