From: dirk.brandewie@gmail.com
To: devicetree-discuss@lists.ozlabs.org
Cc: sodaville@linutronix.de, arjan@linux.intel.com,
dirk.brandewie@gmail.com, linuxppc-dev@lists.ozlabs.org,
microblaze-uclinux@itee.uq.edu.au, linux-arch@vger.kernel.org,
linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 1/5] of: Add support for linking device tree blobs into vmlinux
Date: Tue, 16 Nov 2010 14:41:36 -0800 [thread overview]
Message-ID: <9129f0a21ea48fb2dcb89cea290e88f3e8c0d8a2.1289943240.git.dirk.brandewie@gmail.com> (raw)
In-Reply-To: <cover.1289943240.git.dirk.brandewie@gmail.com>
From: Dirk Brandewie <dirk.brandewie@gmail.com>
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@gmail.com>
---
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
next prev parent reply other threads:[~2010-11-16 22:42 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-16 22:41 [PATCH 0/5] Add the ability to link device blobs into vmlinux dirk.brandewie
2010-11-16 22:41 ` dirk.brandewie [this message]
2010-11-17 0:39 ` [PATCH 1/5] of: Add support for linking device tree " David Daney
2010-11-17 2:21 ` Dirk Brandewie
2010-11-17 2:58 ` Grant Likely
2010-11-17 6:14 ` Dirk Brandewie
2010-11-17 17:54 ` David Daney
2010-11-17 9:27 ` Sam Ravnborg
2010-11-17 18:07 ` Grant Likely
2010-11-17 20:24 ` Sam Ravnborg
2010-11-16 22:41 ` [PATCH 2/5] of/fdt: add kernel command line option for dtb_compat string dirk.brandewie
2010-11-17 0:16 ` Grant Likely
2010-11-16 22:41 ` [PATCH 3/5] x86/of: Add building device tree blob(s) into image dirk.brandewie
2010-11-17 6:02 ` Grant Likely
2010-11-17 6:43 ` Dirk Brandewie
2010-11-16 22:41 ` [PATCH 4/5] of/powerpc: Move build to use generic dts->dtb rule dirk.brandewie
2010-11-17 6:06 ` Grant Likely
2010-11-17 6:32 ` Dirk Brandewie
2010-11-16 22:41 ` [PATCH 5/5] of/microblaze: " dirk.brandewie
2010-12-02 16:31 ` [PATCH 0/4] V2 Add ability to link device blob(s) into vmlinux dirk.brandewie
2010-12-02 16:31 ` [PATCH 1/4] of: Add support for linking device tree blobs " dirk.brandewie
2010-12-02 16:31 ` [PATCH 2/4] x86/of: Add building device tree blob(s) into image dirk.brandewie
2010-12-02 16:31 ` [PATCH 3/4] of/powerpc: Use generic rule to build dtb's dirk.brandewie
2010-12-02 16:31 ` [PATCH 4/4] microblaze/of: " dirk.brandewie
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