refactor(fdt): introduce common fdt_node_is_enabled()
There are several users in the tree which want to check whether a given
FDT node is enabled or not: the "status" property holds that
information. So far all those users provide private implementations,
some of them having issues.
Export a generic implementation of that function in fdt_wrappers.h, as
a "static inline" function to not increase code size.
Also replace the existing implementation in Arm's fconf code, which had
a tiny bug in needlessly using the property length:
"status = [6f 6b 61 79 20];" would pass the check, where it should not.
The proper solution is also simpler: status must be a string, and
strings must be NUL-terminated in a DT. strcmp() would terminate on the
first NUL in *either* of the two strings it compares, so it would never
walk beyond the property boundary in the DTB.
Change-Id: I9d89093432f127c09add6cf5c93a725bc534e5de
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/include/common/fdt_wrappers.h b/include/common/fdt_wrappers.h
index 2929fc2..b16510f 100644
--- a/include/common/fdt_wrappers.h
+++ b/include/common/fdt_wrappers.h
@@ -10,6 +10,7 @@
#define FDT_WRAPPERS_H
#include <libfdt_env.h>
+#include <libfdt.h>
/* Number of cells, given total length in bytes. Each cell is 4 bytes long */
#define NCELLS(len) ((len) / 4U)
@@ -53,6 +54,15 @@
return fdt32_to_cpu(dtb_header[1]);
}
+static inline bool fdt_node_is_enabled(const void *fdt, int node)
+{
+ int len;
+ const void *prop = fdt_getprop(fdt, node, "status", &len);
+
+ /* A non-existing status property means the device is enabled. */
+ return (prop == NULL) || (len == 5 && strcmp(prop, "okay") == 0);
+}
+
#define fdt_for_each_compatible_node(dtb, node, compatible_str) \
for (node = fdt_node_offset_by_compatible(dtb, -1, compatible_str); \
node >= 0; \