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 (filled with garbage) while a pointer to the property data will be provided.
Signed-off-by: Pantelis Antoniou pantelis.antoniou@konsulko.com [dwg: Corrected commit message] Signed-off-by: David Gibson david@gibson.dropbear.id.au --- lib/libfdt/fdt_rw.c | 20 +++++++++++++++++--- lib/libfdt/libfdt.h | 31 +++++++++++++++++++++++++++++++ 2 files changed, 48 insertions(+), 3 deletions(-)
diff --git a/lib/libfdt/fdt_rw.c b/lib/libfdt/fdt_rw.c index 80a3212..3dc7752 100644 --- a/lib/libfdt/fdt_rw.c +++ b/lib/libfdt/fdt_rw.c @@ -228,8 +228,8 @@ int fdt_set_name(void *fdt, int nodeoffset, const char *name) return 0; }
-int fdt_setprop(void *fdt, int nodeoffset, const char *name, - const void *val, int len) +int fdt_setprop_placeholder(void *fdt, int nodeoffset, const char *name, + int len, void **prop_data) { struct fdt_property *prop; int err; @@ -242,8 +242,22 @@ int fdt_setprop(void *fdt, int nodeoffset, const char *name, if (err) return err;
+ *prop_data = prop->data; + return 0; +} + +int fdt_setprop(void *fdt, int nodeoffset, const char *name, + const void *val, int len) +{ + void *prop_data; + int err; + + err = fdt_setprop_placeholder(fdt, nodeoffset, name, len, &prop_data); + if (err) + return err; + if (len) - memcpy(prop->data, val, len); + memcpy(prop_data, val, len); return 0; }
diff --git a/lib/libfdt/libfdt.h b/lib/libfdt/libfdt.h index f3f9cad..6af94cb 100644 --- a/lib/libfdt/libfdt.h +++ b/lib/libfdt/libfdt.h @@ -1405,6 +1405,37 @@ 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 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