Re: [PATCH v2 09/10] libfdt: Handle unknown tags on dtb modifications

From: Frank Li

Date: Thu Jun 04 2026 - 17:35:06 EST

On Thu, Apr 09, 2026 at 01:54:25PM +0200, Herve Codina wrote:
> The structured tag value definition introduced recently gives the
> ability to ignore unknown tags without any error.
>
> When the dtb is modified those unknown tags have to be taken into
> account.
>
> First, depending on the unknown tag location, the item associated with
> the tag is identified:
> - An unknown tag located just after a FDT_BEGIN_NODE is related to the
> node.
>
> - An unknown tag located just after a FDT_PROP is related to the
> property.
>
> - An unknown tag out of any node (i.e located before the first
> FDT_BEGIN_NODE or after the last FDT_END_NODE) is a global tag
> related to the dtb itself.
>
> Then, if we are allowed to write a dtb containing unknown tags, the
> following rules are used:
> - When a property is modified, tags related to this property are
> removed and the dtb version is downgraded.
>
> - When a property is removed, tags related to this property are
> obviously removed. The dtb version is kept unchanged.
>
> - When a property or a node is added, obviously no unknown tags are
> added and the dtb version is kept unchanged.
>
> - When a node is removed, tags related to this node are obviously
> removed. The dtb version is kept unchanged.
>
> - Adding, removing or modifying a property is not considered as a node
> modification and so, those operations have no impacts on unknown
> tags related to the node. Those node related tags are kept unchanged.
>
> - The only modification considered as a node modification is setting
> its name. We consider that this operation has no impact on tags
> related to the node. Here also, those node related tags and the
> dtb version are kept unchanged.
>
> - Global (dtb related) unknown tags are kept unchanged regardless the
> modification done.
>
> Implement those rules when a dtb is modified.
>
> Signed-off-by: Herve Codina <herve.codina@xxxxxxxxxxx>
> Reviewed-by: Luca Ceresoli <luca.ceresoli@xxxxxxxxxxx>
> ---

Reviewed-by: Frank Li <Frank.Li@xxxxxxx>

> libfdt/fdt_rw.c | 118 +++++++++++++++++-
> tests/run_tests.sh | 50 ++++++++
> ...own_tags_can_skip.fdtput.test.dtb.0.expect | 31 +++++
> ...own_tags_can_skip.fdtput.test.dtb.1.expect | 35 ++++++
> ...own_tags_can_skip.fdtput.test.dtb.2.expect | 33 +++++
> ...own_tags_can_skip.fdtput.test.dtb.3.expect | 35 ++++++
> ...own_tags_can_skip.fdtput.test.dtb.4.expect | 34 +++++
> ...own_tags_can_skip.fdtput.test.dtb.5.expect | 32 +++++
> ...own_tags_can_skip.fdtput.test.dtb.6.expect | 27 ++++
> 9 files changed, 394 insertions(+), 1 deletion(-)
> create mode 100644 tests/unknown_tags_can_skip.fdtput.test.dtb.0.expect
> create mode 100644 tests/unknown_tags_can_skip.fdtput.test.dtb.1.expect
> create mode 100644 tests/unknown_tags_can_skip.fdtput.test.dtb.2.expect
> create mode 100644 tests/unknown_tags_can_skip.fdtput.test.dtb.3.expect
> create mode 100644 tests/unknown_tags_can_skip.fdtput.test.dtb.4.expect
> create mode 100644 tests/unknown_tags_can_skip.fdtput.test.dtb.5.expect
> create mode 100644 tests/unknown_tags_can_skip.fdtput.test.dtb.6.expect
>
> diff --git a/libfdt/fdt_rw.c b/libfdt/fdt_rw.c
> index f5c28fc..a8f53b4 100644
> --- a/libfdt/fdt_rw.c
> +++ b/libfdt/fdt_rw.c
> @@ -188,6 +188,60 @@ int fdt_del_mem_rsv(void *fdt, int n)
> return fdt_splice_mem_rsv_(fdt, re, 1, 0);
> }
>
> +static void fdt_nopify_area(void *fdt, int start_offset, int next_offset)
> +{
> + int count = (next_offset - start_offset) / sizeof(fdt32_t);
> + fdt32_t fdt32_nop = cpu_to_fdt32(FDT_NOP);
> + fdt32_t *ptr;
> +
> + ptr = fdt_offset_ptr_w_(fdt, start_offset);
> + while (count--)
> + *(ptr++) = fdt32_nop;
> +};
> +
> +static int fdt_property_remove_unknown_tags(void *fdt,
> + const struct fdt_property *prop,
> + bool downgrade_version)
> +{
> + int nextoffset, offset;
> + bool is_unknown;
> + uint32_t tag;
> +
> + tag = fdt_next_tag(fdt, fdt_ptr_offset_(fdt, prop), &nextoffset);
> + if (tag == FDT_END)
> + return nextoffset;
> +
> + /*
> + * Look at all tags related to the current property. I.e. tags after the
> + * current property and before either the next property, a sub-node or
> + * the end of current node
> + */
> + do {
> + offset = nextoffset;
> + tag = fdt_next_tag_(fdt, offset, &nextoffset, &is_unknown);
> + if (tag == FDT_END)
> + return nextoffset;
> +
> + /*
> + * Unknown tags are returned as NOP. Force FDT_NOP to be really
> + * present in the area to remove the unknown tag and its related
> + * data. Also, as a tag is removed, downgrade the dtb version
> + * if asked for.
> + */
> + if (tag == FDT_NOP) {
> + if (is_unknown) {
> + if (downgrade_version)
> + fdt_downgrade_version(fdt);
> + fdt_nopify_area(fdt, offset, nextoffset);
> + }
> + }
> +
> + } while ((tag != FDT_PROP) && (tag != FDT_BEGIN_NODE) &&
> + (tag != FDT_END_NODE));
> +
> + return 0;
> +}
> +
> static int fdt_resize_property_(void *fdt, int nodeoffset,
> const char *name, int namelen,
> int len, struct fdt_property **prop)
> @@ -200,6 +254,14 @@ static int fdt_resize_property_(void *fdt, int nodeoffset,
> if (!*prop)
> return oldlen;
>
> + /*
> + * The property is resized. Remove possible unknown tags related to the
> + * property downgrading the dtb version.
> + */
> + err = fdt_property_remove_unknown_tags(fdt, *prop, true);
> + if (err)
> + return err;
> +
> if ((err = fdt_splice_struct_(fdt, (*prop)->data, FDT_TAGALIGN(oldlen),
> FDT_TAGALIGN(len))))
> return err;
> @@ -208,6 +270,29 @@ static int fdt_resize_property_(void *fdt, int nodeoffset,
> return 0;
> }
>
> +static int fdt_node_skip_unknown_tags(void *fdt, int next)
> +{
> + int nextoffset = next;
> + int offset;
> + uint32_t tag;
> +
> + /*
> + * Skip all tags related to the current node. I.e. tags after the
> + * current node and before either the next property, a sub-node or the
> + * end of current node.
> + */
> + do {
> + offset = nextoffset;
> + tag = fdt_next_tag(fdt, offset, &nextoffset);
> + if (tag == FDT_END)
> + return nextoffset;
> +
> + } while ((tag != FDT_PROP) && (tag != FDT_BEGIN_NODE) &&
> + (tag != FDT_END_NODE));
> +
> + return offset;
> +}
> +
> static int fdt_add_property_(void *fdt, int nodeoffset, const char *name,
> int namelen, int len, struct fdt_property **prop)
> {
> @@ -220,6 +305,15 @@ static int fdt_add_property_(void *fdt, int nodeoffset, const char *name,
> if ((nextoffset = fdt_check_node_offset_(fdt, nodeoffset)) < 0)
> return nextoffset;
>
> + /*
> + * nextoffset it at the first tag after the node.
> + * Skip possible unknown tags related to the node in order to add the
> + * property after those tags.
> + */
> + nextoffset = fdt_node_skip_unknown_tags(fdt, nextoffset);
> + if (nextoffset < 0)
> + return nextoffset;
> +
> namestroff = fdt_find_add_string_(fdt, name, namelen, &allocated);
> if (namestroff < 0)
> return namestroff;
> @@ -309,6 +403,14 @@ int fdt_appendprop(void *fdt, int nodeoffset, const char *name,
>
> prop = fdt_get_property_w(fdt, nodeoffset, name, &oldlen);
> if (prop) {
> + /*
> + * The property is going to be modified. Remove possible unknown
> + * tags related to this property downgrading the dtb version.
> + */
> + err = fdt_property_remove_unknown_tags(fdt, prop, true);
> + if (err)
> + return err;
> +
> newlen = len + oldlen;
> err = fdt_splice_struct_(fdt, prop->data,
> FDT_TAGALIGN(oldlen),
> @@ -331,6 +433,7 @@ int fdt_delprop(void *fdt, int nodeoffset, const char *name)
> {
> struct fdt_property *prop;
> int len, proplen;
> + int err;
>
> FDT_RW_PROBE(fdt);
>
> @@ -338,6 +441,14 @@ int fdt_delprop(void *fdt, int nodeoffset, const char *name)
> if (!prop)
> return len;
>
> + /*
> + * The property is going to be removed. Remove also possible unknown
> + * tags related to this property. Keep the dtb version unchanged.
> + */
> + err = fdt_property_remove_unknown_tags(fdt, prop, false);
> + if (err)
> + return err;
> +
> proplen = sizeof(*prop) + FDT_TAGALIGN(len);
> return fdt_splice_struct_(fdt, prop, proplen, 0);
> }
> @@ -366,7 +477,12 @@ int fdt_add_subnode_namelen(void *fdt, int parentoffset,
> else if (offset != -FDT_ERR_NOTFOUND)
> return offset;
>
> - /* Try to place the new node after the parent's properties */
> + /*
> + * Try to place the new node after the parent's properties and unknown
> + * tags related to those properties.
> + * Unknown tags are reported as FDT_NOP tags by fdt_next_tag.
> + * Skipping FDT_NOP tags will correctly skip unknown tags.
> + */
> tag = fdt_next_tag(fdt, parentoffset, &nextoffset);
> /* the fdt_subnode_offset_namelen() should ensure this never hits */
> if (!can_assume(LIBFDT_FLAWLESS) && (tag != FDT_BEGIN_NODE))
> diff --git a/tests/run_tests.sh b/tests/run_tests.sh
> index 48ac6fa..1ba937d 100755
> --- a/tests/run_tests.sh
> +++ b/tests/run_tests.sh
> @@ -1043,6 +1043,56 @@ fdtput_tests () {
> run_wrap_error_test $DTPUT $dtb -d /chosen non-existent-prop
>
> # TODO: Add tests for verbose mode?
> +
> + # Modify a dtb containing some "unknown" tags that can be skipped
> + dtb=unknown_tags_can_skip.fdtput.test.dtb
> + cp unknown_tags_can_skip.dtb $dtb
> + base_run_test wrap_fdtdump $dtb $dtb.0.out
> + # Remove unneeded header fields (keep those related to versions)
> + sed -i '/^\/.*$magic\|off\|size\|cpu$/d' $dtb.0.out
> + base_run_test check_diff $dtb.0.out "$SRCDIR/$dtb.0.expect"
> +
> + run_fdtput_test "vwxyz" $dtb / prop-str -ts "vwxyz"
> + base_run_test wrap_fdtdump $dtb $dtb.1.out
> + # Remove unneeded header fields (keep those related to versions)
> + sed -i '/^\/.*$magic\|off\|size\|cpu$/d' $dtb.1.out
> + base_run_test check_diff $dtb.1.out "$SRCDIR/$dtb.1.expect"
> +
> + cp unknown_tags_can_skip.dtb $dtb
> + run_wrap_test $DTPUT $dtb -c /tst-fdtput
> + base_run_test wrap_fdtdump $dtb $dtb.2.out
> + # Remove unneeded header fields (keep those related to versions)
> + sed -i '/^\/.*$magic\|off\|size\|cpu$/d' $dtb.2.out
> + base_run_test check_diff $dtb.2.out "$SRCDIR/$dtb.2.expect"
> + run_wrap_test $DTPUT $dtb -c /tst-fdtput/n1 /tst-fdtput/n2 /tst-fdtput/n3
> + run_wrap_test $DTPUT $dtb -r /tst-fdtput/n1 /tst-fdtput/n3
> + run_fdtget_test "n2" $dtb -l /tst-fdtput
> + base_run_test wrap_fdtdump $dtb $dtb.3.out
> + # Remove unneeded header fields (keep those related to versions)
> + sed -i '/^\/.*$magic\|off\|size\|cpu$/d' $dtb.3.out
> + base_run_test check_diff $dtb.3.out "$SRCDIR/$dtb.3.expect"
> +
> + cp unknown_tags_can_skip.dtb $dtb
> + run_wrap_test $DTPUT $dtb -d / prop-str
> + run_fdtget_test "prop-int" $dtb -p /
> + base_run_test wrap_fdtdump $dtb $dtb.4.out
> + # Remove unneeded header fields (keep those related to versions)
> + sed -i '/^\/.*$magic\|off\|size\|cpu$/d' $dtb.4.out
> + base_run_test check_diff $dtb.4.out "$SRCDIR/$dtb.4.expect"
> +
> + cp unknown_tags_can_skip.dtb $dtb
> + run_wrap_test $DTPUT $dtb /subnode2 prop-tst-fdtput -ts "Test fdtput"
> + base_run_test wrap_fdtdump $dtb $dtb.5.out
> + # Remove unneeded header fields (keep those related to versions)
> + sed -i '/^\/.*$magic\|off\|size\|cpu$/d' $dtb.5.out
> + base_run_test check_diff $dtb.5.out "$SRCDIR/$dtb.5.expect"
> +
> + cp unknown_tags_can_skip.dtb $dtb
> + run_wrap_test $DTPUT $dtb -r /subnode2/subsubnode
> + base_run_test wrap_fdtdump $dtb $dtb.6.out
> + # Remove unneeded header fields (keep those related to versions)
> + sed -i '/^\/.*$magic\|off\|size\|cpu$/d' $dtb.6.out
> + base_run_test check_diff $dtb.6.out "$SRCDIR/$dtb.6.expect"
> }
>
> utilfdt_tests () {
> diff --git a/tests/unknown_tags_can_skip.fdtput.test.dtb.0.expect b/tests/unknown_tags_can_skip.fdtput.test.dtb.0.expect
> new file mode 100644
> index 0000000..3cdf448
> --- /dev/null
> +++ b/tests/unknown_tags_can_skip.fdtput.test.dtb.0.expect
> @@ -0,0 +1,31 @@
> +/dts-v1/;
> +// version: 4294967295
> +// last_comp_version: 16
> +
> +// Unknown tag ignored: 0xd0000000, data len 4 00000001
> +/ {
> + // Unknown tag ignored: 0xc0000000, data len 0
> + prop-int = <0x00003201>;
> + // Unknown tag ignored: 0xd0000000, data len 4 00000110
> + prop-str = "abcd";
> + // Unknown tag ignored: 0xe0000000, data len 8 0000012000000121
> + // Unknown tag ignored: 0xf0000000, data len 3 101112
> + subnode1 {
> + prop-int = <0x00006401 0x00006402>;
> + // Unknown tag ignored: 0xc0000000, data len 0
> + };
> + subnode2 {
> + // Unknown tag ignored: 0xd0000000, data len 4 00000121
> + prop-int1 = <0x00064020 0x00064021>;
> + // Unknown tag ignored: 0xe0000000, data len 8 0000122000001221
> + prop-int2 = <0x00032022>;
> + subsubnode {
> + // Unknown tag ignored: 0xe0000000, data len 8 0000123000001231
> + prop-int = <0x00064023 0x00064024>;
> + };
> + // Unknown tag ignored: 0xf0000000, data len 3 212223
> + };
> + // Unknown tag ignored: 0xf0000000, data len 5 3132333435
> +};
> +// Unknown tag ignored: 0xd0000000, data len 4 00000002
> +// Unknown tag ignored: 0xf0000000, data len 2 4041
> diff --git a/tests/unknown_tags_can_skip.fdtput.test.dtb.1.expect b/tests/unknown_tags_can_skip.fdtput.test.dtb.1.expect
> new file mode 100644
> index 0000000..71f2d1c
> --- /dev/null
> +++ b/tests/unknown_tags_can_skip.fdtput.test.dtb.1.expect
> @@ -0,0 +1,35 @@
> +/dts-v1/;
> +// version: 17
> +// last_comp_version: 16
> +
> +// Unknown tag ignored: 0xd0000000, data len 4 00000001
> +/ {
> + // Unknown tag ignored: 0xc0000000, data len 0
> + prop-int = <0x00003201>;
> + // Unknown tag ignored: 0xd0000000, data len 4 00000110
> + prop-str = "vwxyz";
> + // [NOP]
> + // [NOP]
> + // [NOP]
> + // [NOP]
> + // [NOP]
> + // [NOP]
> + subnode1 {
> + prop-int = <0x00006401 0x00006402>;
> + // Unknown tag ignored: 0xc0000000, data len 0
> + };
> + subnode2 {
> + // Unknown tag ignored: 0xd0000000, data len 4 00000121
> + prop-int1 = <0x00064020 0x00064021>;
> + // Unknown tag ignored: 0xe0000000, data len 8 0000122000001221
> + prop-int2 = <0x00032022>;
> + subsubnode {
> + // Unknown tag ignored: 0xe0000000, data len 8 0000123000001231
> + prop-int = <0x00064023 0x00064024>;
> + };
> + // Unknown tag ignored: 0xf0000000, data len 3 212223
> + };
> + // Unknown tag ignored: 0xf0000000, data len 5 3132333435
> +};
> +// Unknown tag ignored: 0xd0000000, data len 4 00000002
> +// Unknown tag ignored: 0xf0000000, data len 2 4041
> diff --git a/tests/unknown_tags_can_skip.fdtput.test.dtb.2.expect b/tests/unknown_tags_can_skip.fdtput.test.dtb.2.expect
> new file mode 100644
> index 0000000..bd3a13b
> --- /dev/null
> +++ b/tests/unknown_tags_can_skip.fdtput.test.dtb.2.expect
> @@ -0,0 +1,33 @@
> +/dts-v1/;
> +// version: 17
> +// last_comp_version: 16
> +
> +// Unknown tag ignored: 0xd0000000, data len 4 00000001
> +/ {
> + // Unknown tag ignored: 0xc0000000, data len 0
> + prop-int = <0x00003201>;
> + // Unknown tag ignored: 0xd0000000, data len 4 00000110
> + prop-str = "abcd";
> + // Unknown tag ignored: 0xe0000000, data len 8 0000012000000121
> + // Unknown tag ignored: 0xf0000000, data len 3 101112
> + tst-fdtput {
> + };
> + subnode1 {
> + prop-int = <0x00006401 0x00006402>;
> + // Unknown tag ignored: 0xc0000000, data len 0
> + };
> + subnode2 {
> + // Unknown tag ignored: 0xd0000000, data len 4 00000121
> + prop-int1 = <0x00064020 0x00064021>;
> + // Unknown tag ignored: 0xe0000000, data len 8 0000122000001221
> + prop-int2 = <0x00032022>;
> + subsubnode {
> + // Unknown tag ignored: 0xe0000000, data len 8 0000123000001231
> + prop-int = <0x00064023 0x00064024>;
> + };
> + // Unknown tag ignored: 0xf0000000, data len 3 212223
> + };
> + // Unknown tag ignored: 0xf0000000, data len 5 3132333435
> +};
> +// Unknown tag ignored: 0xd0000000, data len 4 00000002
> +// Unknown tag ignored: 0xf0000000, data len 2 4041
> diff --git a/tests/unknown_tags_can_skip.fdtput.test.dtb.3.expect b/tests/unknown_tags_can_skip.fdtput.test.dtb.3.expect
> new file mode 100644
> index 0000000..237eb95
> --- /dev/null
> +++ b/tests/unknown_tags_can_skip.fdtput.test.dtb.3.expect
> @@ -0,0 +1,35 @@
> +/dts-v1/;
> +// version: 17
> +// last_comp_version: 16
> +
> +// Unknown tag ignored: 0xd0000000, data len 4 00000001
> +/ {
> + // Unknown tag ignored: 0xc0000000, data len 0
> + prop-int = <0x00003201>;
> + // Unknown tag ignored: 0xd0000000, data len 4 00000110
> + prop-str = "abcd";
> + // Unknown tag ignored: 0xe0000000, data len 8 0000012000000121
> + // Unknown tag ignored: 0xf0000000, data len 3 101112
> + tst-fdtput {
> + n2 {
> + };
> + };
> + subnode1 {
> + prop-int = <0x00006401 0x00006402>;
> + // Unknown tag ignored: 0xc0000000, data len 0
> + };
> + subnode2 {
> + // Unknown tag ignored: 0xd0000000, data len 4 00000121
> + prop-int1 = <0x00064020 0x00064021>;
> + // Unknown tag ignored: 0xe0000000, data len 8 0000122000001221
> + prop-int2 = <0x00032022>;
> + subsubnode {
> + // Unknown tag ignored: 0xe0000000, data len 8 0000123000001231
> + prop-int = <0x00064023 0x00064024>;
> + };
> + // Unknown tag ignored: 0xf0000000, data len 3 212223
> + };
> + // Unknown tag ignored: 0xf0000000, data len 5 3132333435
> +};
> +// Unknown tag ignored: 0xd0000000, data len 4 00000002
> +// Unknown tag ignored: 0xf0000000, data len 2 4041
> diff --git a/tests/unknown_tags_can_skip.fdtput.test.dtb.4.expect b/tests/unknown_tags_can_skip.fdtput.test.dtb.4.expect
> new file mode 100644
> index 0000000..8473040
> --- /dev/null
> +++ b/tests/unknown_tags_can_skip.fdtput.test.dtb.4.expect
> @@ -0,0 +1,34 @@
> +/dts-v1/;
> +// version: 17
> +// last_comp_version: 16
> +
> +// Unknown tag ignored: 0xd0000000, data len 4 00000001
> +/ {
> + // Unknown tag ignored: 0xc0000000, data len 0
> + prop-int = <0x00003201>;
> + // Unknown tag ignored: 0xd0000000, data len 4 00000110
> + // [NOP]
> + // [NOP]
> + // [NOP]
> + // [NOP]
> + // [NOP]
> + // [NOP]
> + subnode1 {
> + prop-int = <0x00006401 0x00006402>;
> + // Unknown tag ignored: 0xc0000000, data len 0
> + };
> + subnode2 {
> + // Unknown tag ignored: 0xd0000000, data len 4 00000121
> + prop-int1 = <0x00064020 0x00064021>;
> + // Unknown tag ignored: 0xe0000000, data len 8 0000122000001221
> + prop-int2 = <0x00032022>;
> + subsubnode {
> + // Unknown tag ignored: 0xe0000000, data len 8 0000123000001231
> + prop-int = <0x00064023 0x00064024>;
> + };
> + // Unknown tag ignored: 0xf0000000, data len 3 212223
> + };
> + // Unknown tag ignored: 0xf0000000, data len 5 3132333435
> +};
> +// Unknown tag ignored: 0xd0000000, data len 4 00000002
> +// Unknown tag ignored: 0xf0000000, data len 2 4041
> diff --git a/tests/unknown_tags_can_skip.fdtput.test.dtb.5.expect b/tests/unknown_tags_can_skip.fdtput.test.dtb.5.expect
> new file mode 100644
> index 0000000..f7806f4
> --- /dev/null
> +++ b/tests/unknown_tags_can_skip.fdtput.test.dtb.5.expect
> @@ -0,0 +1,32 @@
> +/dts-v1/;
> +// version: 17
> +// last_comp_version: 16
> +
> +// Unknown tag ignored: 0xd0000000, data len 4 00000001
> +/ {
> + // Unknown tag ignored: 0xc0000000, data len 0
> + prop-int = <0x00003201>;
> + // Unknown tag ignored: 0xd0000000, data len 4 00000110
> + prop-str = "abcd";
> + // Unknown tag ignored: 0xe0000000, data len 8 0000012000000121
> + // Unknown tag ignored: 0xf0000000, data len 3 101112
> + subnode1 {
> + prop-int = <0x00006401 0x00006402>;
> + // Unknown tag ignored: 0xc0000000, data len 0
> + };
> + subnode2 {
> + // Unknown tag ignored: 0xd0000000, data len 4 00000121
> + prop-tst-fdtput = "Test fdtput";
> + prop-int1 = <0x00064020 0x00064021>;
> + // Unknown tag ignored: 0xe0000000, data len 8 0000122000001221
> + prop-int2 = <0x00032022>;
> + subsubnode {
> + // Unknown tag ignored: 0xe0000000, data len 8 0000123000001231
> + prop-int = <0x00064023 0x00064024>;
> + };
> + // Unknown tag ignored: 0xf0000000, data len 3 212223
> + };
> + // Unknown tag ignored: 0xf0000000, data len 5 3132333435
> +};
> +// Unknown tag ignored: 0xd0000000, data len 4 00000002
> +// Unknown tag ignored: 0xf0000000, data len 2 4041
> diff --git a/tests/unknown_tags_can_skip.fdtput.test.dtb.6.expect b/tests/unknown_tags_can_skip.fdtput.test.dtb.6.expect
> new file mode 100644
> index 0000000..029f3b4
> --- /dev/null
> +++ b/tests/unknown_tags_can_skip.fdtput.test.dtb.6.expect
> @@ -0,0 +1,27 @@
> +/dts-v1/;
> +// version: 17
> +// last_comp_version: 16
> +
> +// Unknown tag ignored: 0xd0000000, data len 4 00000001
> +/ {
> + // Unknown tag ignored: 0xc0000000, data len 0
> + prop-int = <0x00003201>;
> + // Unknown tag ignored: 0xd0000000, data len 4 00000110
> + prop-str = "abcd";
> + // Unknown tag ignored: 0xe0000000, data len 8 0000012000000121
> + // Unknown tag ignored: 0xf0000000, data len 3 101112
> + subnode1 {
> + prop-int = <0x00006401 0x00006402>;
> + // Unknown tag ignored: 0xc0000000, data len 0
> + };
> + subnode2 {
> + // Unknown tag ignored: 0xd0000000, data len 4 00000121
> + prop-int1 = <0x00064020 0x00064021>;
> + // Unknown tag ignored: 0xe0000000, data len 8 0000122000001221
> + prop-int2 = <0x00032022>;
> + // Unknown tag ignored: 0xf0000000, data len 3 212223
> + };
> + // Unknown tag ignored: 0xf0000000, data len 5 3132333435
> +};
> +// Unknown tag ignored: 0xd0000000, data len 4 00000002
> +// Unknown tag ignored: 0xf0000000, data len 2 4041
> --
> 2.53.0
>