libfdt: Add new errors for the overlay code

Add a few new error codes to report the failure conditions we might
encounter in the overlay application code:
   - FDT_ERR_BADOVERLAY, when an overlay cannot be parsed, even though its
     structure is correct
   - FDT_ERR_NOPHANDLES, when we ran out of available phandles and we
     cannot use a new phandle without either using an invalid one (-1 or
     0), or one already used.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

libfdt/fdt_strerror.c

@@ -76,6 +76,9 @@ static struct fdt_errtabent fdt_errtable[] = {
 	FDT_ERRTABENT(FDT_ERR_BADVERSION),
 	FDT_ERRTABENT(FDT_ERR_BADSTRUCTURE),
 	FDT_ERRTABENT(FDT_ERR_BADLAYOUT),
+	FDT_ERRTABENT(FDT_ERR_BADOVERLAY),
+	FDT_ERRTABENT(FDT_ERR_BADOVERLAY),
+	FDT_ERRTABENT(FDT_ERR_NOPHANDLES),
 };
 #define FDT_ERRTABSIZE	(sizeof(fdt_errtable) / sizeof(fdt_errtable[0]))
 

libfdt/libfdt.h

@@ -126,7 +126,16 @@
 	 * value. For example: a property expected to contain a string list
 	 * is not NUL-terminated within the length of its value. */
 
-#define FDT_ERR_MAX		15
+#define FDT_ERR_BADOVERLAY	16
+	/* FDT_ERR_BADOVERLAY: The device tree overlay, while
+	 * correctly structured, cannot be applied due to some
+	 * unexpected or missing value, property or node. */
+
+#define FDT_ERR_NOPHANDLES	17
+	/* FDT_ERR_NOPHANDLES: The device tree doesn't have any
+	 * phandle available anymore without causing an overflow */
+
+#define FDT_ERR_MAX		17
 
 /**********************************************************************/
 /* Low-level functions (you probably don't need these)                */