fdt: Add a function to remove unused strings from a device tree

[karo-tx-uboot.git] / lib / libfdt / fdt_rw.c

diff --git a/lib/libfdt/fdt_rw.c b/lib/libfdt/fdt_rw.c
index bec8b8ad891846e5240c476cf3b15e34eb3f66e8..1a358a8ca0a6f59e8652a8d92fd712d53bf96408 100644 (file)
--- 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;
+}