From 8f6e2e1ee17bb1ecce03518b8eceda6965617477 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Tue, 23 Jun 2015 15:38:26 -0600 Subject: fdt: Add a function to remove unused strings from a device tree Property names are stored in a string table. When a node property is removed, the string table is not updated since other nodes may have a property with the same name. Thus it is possible for the string table to build up a number of unused strings. Add a function to remove these. This works by building a new device tree from the old one, adding strings one by one as needed. Signed-off-by: Simon Glass --- lib/libfdt/fdt_rw.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) (limited to 'lib/libfdt/fdt_rw.c') diff --git a/lib/libfdt/fdt_rw.c b/lib/libfdt/fdt_rw.c index bec8b8ad89..1a358a8ca0 100644 --- a/lib/libfdt/fdt_rw.c +++ b/lib/libfdt/fdt_rw.c @@ -449,3 +449,35 @@ int fdt_pack(void *fdt) return 0; } + +int fdt_remove_unused_strings(const void *old, void *new) +{ + const struct fdt_property *old_prop; + struct fdt_property *new_prop; + int size = fdt_totalsize(old); + int next_offset, offset; + const char *str; + int ret; + int tag = FDT_PROP; + + /* Make a copy and remove the strings */ + memcpy(new, old, size); + fdt_set_size_dt_strings(new, 0); + + /* Add every property name back into the new string table */ + for (offset = 0; tag != FDT_END; offset = next_offset) { + tag = fdt_next_tag(old, offset, &next_offset); + if (tag != FDT_PROP) + continue; + old_prop = fdt_get_property_by_offset(old, offset, NULL); + new_prop = (struct fdt_property *)(unsigned long) + fdt_get_property_by_offset(new, offset, NULL); + str = fdt_string(old, fdt32_to_cpu(old_prop->nameoff)); + ret = _fdt_find_add_string(new, str); + if (ret < 0) + return ret; + new_prop->nameoff = cpu_to_fdt32(ret); + } + + return 0; +} -- cgit v1.2.1