[RFC PATCH v2 02/74] Introduce v20 dtb version
From: Herve Codina
Date: Wed Aug 26 2026 - 05:50:55 EST
This v20 version will add support for
- metadata in device-tree blobs in order to have a better handling of
phandles and unresolved references.
- Addon device-tree blob (successor of device-tree overlay)
- Import and export symbols feature
- multiple trees in an addon device-tree blob (i.e. root device tree
and orphan node tree)
Signed-off-by: Herve Codina <herve.codina@xxxxxxxxxxx>
---
dtc.h | 2 +-
fdtdump.c | 2 +-
flattree.c | 3 +++
libfdt/fdt.h | 1 +
libfdt/fdt_rw.c | 13 +++++++------
libfdt/libfdt.h | 6 +++---
tests/pylibfdt_tests.py | 6 +++---
tests/treegen.c | 2 +-
.../unknown_tags_can_skip.fdtput.test.dtb.1.expect | 2 +-
tests/unknown_tags_can_skip.wip.test.dtb.1.expect | 2 +-
10 files changed, 22 insertions(+), 17 deletions(-)
diff --git a/dtc.h b/dtc.h
index f0c2cde6..ef3f2682 100644
--- a/dtc.h
+++ b/dtc.h
@@ -29,7 +29,7 @@
#define debug(...)
#endif
-#define DEFAULT_FDT_VERSION 18
+#define DEFAULT_FDT_VERSION 20
/*
* Command line options
diff --git a/fdtdump.c b/fdtdump.c
index 5994e1d7..20854752 100644
--- a/fdtdump.c
+++ b/fdtdump.c
@@ -18,7 +18,7 @@
#include "util.h"
#define FDT_MAGIC_SIZE 4
-#define MAX_VERSION 18U
+#define MAX_VERSION 20U
#define ALIGN(x, a) (((x) + ((a) - 1)) & ~((a) - 1))
#define PALIGN(p, a) ((void *)(ALIGN((uintptr_t)(p), (a))))
diff --git a/flattree.c b/flattree.c
index ff57fc5d..dd451f0c 100644
--- a/flattree.c
+++ b/flattree.c
@@ -36,6 +36,9 @@ static struct version_info {
{18, 16, 17, FDT_V18_SIZE,
FTF_BOOTCPUID|FTF_STRTABSIZE|FTF_STRUCTSIZE|FTF_NOPS|FTF_DTFLAGS|
FTF_LCVERSW},
+ {20, 18, 18, FDT_V20_SIZE,
+ FTF_BOOTCPUID|FTF_STRTABSIZE|FTF_STRUCTSIZE|FTF_NOPS|FTF_DTFLAGS|
+ FTF_LCVERSW},
};
struct emitter {
diff --git a/libfdt/fdt.h b/libfdt/fdt.h
index a43b85c1..7c59fed2 100644
--- a/libfdt/fdt.h
+++ b/libfdt/fdt.h
@@ -90,5 +90,6 @@ struct fdt_property {
#define FDT_V16_SIZE FDT_V3_SIZE
#define FDT_V17_SIZE (FDT_V16_SIZE + sizeof(fdt32_t))
#define FDT_V18_SIZE (FDT_V17_SIZE + 2 * sizeof(fdt32_t))
+#define FDT_V20_SIZE FDT_V18_SIZE
#endif /* FDT_H */
diff --git a/libfdt/fdt_rw.c b/libfdt/fdt_rw.c
index 005efde8..1c6ce0a3 100644
--- a/libfdt/fdt_rw.c
+++ b/libfdt/fdt_rw.c
@@ -628,10 +628,11 @@ int fdt_open_into(const void *fdt, void *buf, int bufsize)
err = fdt_move(fdt, buf, bufsize);
if (err)
return err;
- if (can_assume(LATEST) || fdt_version(fdt) < 18) {
- fdt_set_version(buf, 18);
+
+ if (can_assume(LATEST) || fdt_version(fdt) < 20) {
+ fdt_set_version(buf, 20);
fdt_set_dt_flags(buf, 0);
- fdt_set_last_comp_version_w(buf, 17);
+ fdt_set_last_comp_version_w(buf, 18);
}
fdt_set_size_dt_struct(buf, struct_size);
fdt_set_totalsize(buf, bufsize);
@@ -661,10 +662,10 @@ int fdt_open_into(const void *fdt, void *buf, int bufsize)
fdt_set_magic(buf, FDT_MAGIC);
fdt_set_totalsize(buf, bufsize);
- fdt_set_version(buf, 18);
- fdt_set_last_comp_version(buf, 16);
+ fdt_set_version(buf, 20);
+ fdt_set_last_comp_version(buf, 18);
fdt_set_dt_flags(buf, 0);
- fdt_set_last_comp_version_w(buf, 17);
+ fdt_set_last_comp_version_w(buf, 18);
fdt_set_boot_cpuid_phys(buf, fdt_boot_cpuid_phys(fdt));
return 0;
diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
index 8e99e644..5e1e0d06 100644
--- a/libfdt/libfdt.h
+++ b/libfdt/libfdt.h
@@ -14,9 +14,9 @@ extern "C" {
#endif
#define FDT_FIRST_SUPPORTED_VERSION 0x02
-#define FDT_LAST_COMPATIBLE_VERSION 0x10
-#define FDT_LAST_COMPATIBLE_VERSION_W 0x11
-#define FDT_LAST_SUPPORTED_VERSION 0x12
+#define FDT_LAST_COMPATIBLE_VERSION 0x12
+#define FDT_LAST_COMPATIBLE_VERSION_W 0x12
+#define FDT_LAST_SUPPORTED_VERSION 0x14
/* Error codes: informative error codes */
#define FDT_ERR_NOTFOUND 1
diff --git a/tests/pylibfdt_tests.py b/tests/pylibfdt_tests.py
index c3aaf00f..bae52406 100644
--- a/tests/pylibfdt_tests.py
+++ b/tests/pylibfdt_tests.py
@@ -277,13 +277,13 @@ class PyLibfdtBasicTests(unittest.TestCase):
self.assertEqual(self.fdt.off_dt_struct(), 96)
self.assertEqual(self.fdt.off_dt_strings(), 660)
self.assertEqual(self.fdt.off_mem_rsvmap(), 48)
- self.assertEqual(self.fdt.version(), 18)
- self.assertEqual(self.fdt.last_comp_version(), 16)
+ self.assertEqual(self.fdt.version(), 20)
+ self.assertEqual(self.fdt.last_comp_version(), 18)
self.assertEqual(self.fdt.boot_cpuid_phys(), 0)
self.assertEqual(self.fdt.size_dt_strings(), 105)
self.assertEqual(self.fdt.size_dt_struct(), 564)
self.assertEqual(self.fdt.dt_flags(), 0)
- self.assertEqual(self.fdt.last_comp_version_w(), 17)
+ self.assertEqual(self.fdt.last_comp_version_w(), 18)
def testPack(self):
"""Test that we can pack the tree after deleting something"""
diff --git a/tests/treegen.c b/tests/treegen.c
index b0730ef6..36cb5508 100644
--- a/tests/treegen.c
+++ b/tests/treegen.c
@@ -127,7 +127,7 @@ static size_t emit_fdt_header_vers(struct buf *b, uint32_t version,
static size_t emit_fdt_header(struct buf *b)
{
- return emit_fdt_header_vers(b, 0x12, 0x10, 0x11);
+ return emit_fdt_header_vers(b, 0x14, 0x12, 0x12);
}
static void finish_rsvmap(struct buf *b, size_t hdr, size_t rsvmap)
diff --git a/tests/unknown_tags_can_skip.fdtput.test.dtb.1.expect b/tests/unknown_tags_can_skip.fdtput.test.dtb.1.expect
index 6d750f88..204d3d23 100644
--- a/tests/unknown_tags_can_skip.fdtput.test.dtb.1.expect
+++ b/tests/unknown_tags_can_skip.fdtput.test.dtb.1.expect
@@ -1,5 +1,5 @@
/dts-v1/;
-// version: 18
+// version: 20
// last_comp_version: 16
// last_comp_version_w: 17
diff --git a/tests/unknown_tags_can_skip.wip.test.dtb.1.expect b/tests/unknown_tags_can_skip.wip.test.dtb.1.expect
index afd8a4af..a3f9307f 100644
--- a/tests/unknown_tags_can_skip.wip.test.dtb.1.expect
+++ b/tests/unknown_tags_can_skip.wip.test.dtb.1.expect
@@ -1,5 +1,5 @@
/dts-v1/;
-// version: 18
+// version: 20
// last_comp_version: 16
// last_comp_version_w: 17
--
2.55.0