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authorSimon Glass <sjg@chromium.org>2016-02-22 22:55:39 -0700
committerTom Rini <trini@konsulko.com>2016-03-14 14:19:11 -0400
commitf8a2d7a4162d2c8ca6adbb1fe0ef7d2a9765c923 (patch)
tree34545d4396f01a984035300d3891b453466205d0
parentcc7a64447bc3e90a8133b2fce98d7526089a7033 (diff)
libfdt: Add a function to write a property placeholder
The existing function to add a new property to a tree being built requires that the entire contents of the new property be passed in. For some applications it is more convenient to be able to add the property contents later, perhaps by reading from a file. This avoids double-buffering of the contents. Add a new function to support this and adust the existing fdt_property() to use it. Signed-off-by: Simon Glass <sjg@chromium.org>
-rw-r--r--include/libfdt.h16
-rw-r--r--lib/libfdt/fdt_sw.c16
2 files changed, 30 insertions, 2 deletions
diff --git a/include/libfdt.h b/include/libfdt.h
index e48c21aced0..74b1d149c2d 100644
--- a/include/libfdt.h
+++ b/include/libfdt.h
@@ -1181,6 +1181,22 @@ static inline int fdt_property_cell(void *fdt, const char *name, uint32_t val)
{
return fdt_property_u32(fdt, name, val);
}
+
+/**
+ * fdt_property_placeholder - add a new property and return a ptr to its value
+ *
+ * @fdt: pointer to the device tree blob
+ * @name: name of property to add
+ * @len: length of property value in bytes
+ * @valp: returns a pointer to where where the value should be placed
+ *
+ * returns:
+ * 0, on success
+ * -FDT_ERR_BADMAGIC,
+ * -FDT_ERR_NOSPACE, standard meanings
+ */
+int fdt_property_placeholder(void *fdt, const char *name, int len, void **valp);
+
#define fdt_property_string(fdt, name, str) \
fdt_property(fdt, name, str, strlen(str)+1)
int fdt_end_node(void *fdt);
diff --git a/lib/libfdt/fdt_sw.c b/lib/libfdt/fdt_sw.c
index 320a914991a..345a3acbf8e 100644
--- a/lib/libfdt/fdt_sw.c
+++ b/lib/libfdt/fdt_sw.c
@@ -175,7 +175,7 @@ static int _fdt_find_add_string(void *fdt, const char *s)
return offset;
}
-int fdt_property(void *fdt, const char *name, const void *val, int len)
+int fdt_property_placeholder(void *fdt, const char *name, int len, void **valp)
{
struct fdt_property *prop;
int nameoff;
@@ -193,7 +193,19 @@ int fdt_property(void *fdt, const char *name, const void *val, int len)
prop->tag = cpu_to_fdt32(FDT_PROP);
prop->nameoff = cpu_to_fdt32(nameoff);
prop->len = cpu_to_fdt32(len);
- memcpy(prop->data, val, len);
+ *valp = prop->data;
+ return 0;
+}
+
+int fdt_property(void *fdt, const char *name, const void *val, int len)
+{
+ void *ptr;
+ int ret;
+
+ ret = fdt_property_placeholder(fdt, name, len, &ptr);
+ if (ret)
+ return ret;
+ memcpy(ptr, val, len);
return 0;
}