In some cases you need to add a property but the contents of it
are not known at creation time, merely the extend of it.
This method allows you to create a property of a given size
which will be set to zero while a pointer to the property data
will be provided.
Signed-off-by: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>
---
libfdt/fdt_rw.c | 21 +++++++++++++++++++++
libfdt/libfdt.h | 32 ++++++++++++++++++++++++++++++++
2 files changed, 53 insertions(+)
diff --git a/libfdt/fdt_rw.c b/libfdt/fdt_rw.c
index 8b487f6..2b4432f 100644
--- a/libfdt/fdt_rw.c
+++ b/libfdt/fdt_rw.c
@@ -288,6 +288,27 @@ int fdt_setprop(void *fdt, int nodeoffset, const char *name,
return 0;
}
+int fdt_setprop_placeholder(void *fdt, int nodeoffset, const char *name,
+ int len, void **prop_data)
+{
+ struct fdt_property *prop;
+ int err;
+
+ FDT_RW_CHECK_HEADER(fdt);
+
+ err = _fdt_resize_property(fdt, nodeoffset, name, len, &prop);
+ if (err == -FDT_ERR_NOTFOUND)
+ err = _fdt_add_property(fdt, nodeoffset, name, len, &prop);
+ if (err)
+ return err;
+
+ if (len)
+ memset(prop->data, 0, len);
+ if (prop_data)
+ *prop_data = prop->data;
+ return 0;
+}
+
int fdt_appendprop(void *fdt, int nodeoffset, const char *name,
const void *val, int len)
{
diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
index a248b1b..7ea9a0c 100644
--- a/libfdt/libfdt.h
+++ b/libfdt/libfdt.h
@@ -1449,6 +1449,38 @@ int fdt_setprop(void *fdt, int nodeoffset, const char *name,
const void *val, int len);
/**
+ * fdt_setprop _placeholder - allocate space for a property
+ * @fdt: pointer to the device tree blob
+ * @nodeoffset: offset of the node whose property to change
+ * @name: name of the property to change
+ * @len: length of the property value
+ * @prop_data: return pointer to property data
+ *
+ * fdt_setprop_placeholer() allocates the named property in the given node.
+ * If the property exists it is resized. In either case it filled with
+ * zeroes and if a prop_data argument is provided a pointer to the
+ * property data is returned.
+ *
+ * This function may insert or delete data from the blob, and will
+ * therefore change the offsets of some existing nodes.
+ *
+ * returns:
+ * 0, on success
+ * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
+ * contain the new property value
+ * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
+ * -FDT_ERR_BADLAYOUT,
+ * -FDT_ERR_BADMAGIC,
+ * -FDT_ERR_BADVERSION,
+ * -FDT_ERR_BADSTATE,
+ * -FDT_ERR_BADSTRUCTURE,
+ * -FDT_ERR_BADLAYOUT,
+ * -FDT_ERR_TRUNCATED, standard meanings
+ */
+int fdt_setprop_placeholder(void *fdt, int nodeoffset, const char *name,
+ int len, void **prop_data);
+
+/**
* fdt_setprop_u32 - set a property to a 32-bit integer
* @fdt: pointer to the device tree blob
* @nodeoffset: offset of the node whose property to change
--
2.1.4
--
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