board: cssi: Create dedicated file for common sources

In preparation of the new cssi board called cmpcpro which
we be introduce in a future patch, move common
functions into a dedicated file in a common directory.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
diff --git a/board/cssi/common/common.c b/board/cssi/common/common.c
new file mode 100644
index 0000000..71b35cc
--- /dev/null
+++ b/board/cssi/common/common.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2010-2020 CS Group
+ * Charles Frey <charles.frey@c-s.fr>
+ * Florent Trinh Thai <florent.trinh-thai@c-s.fr>
+ * Christophe Leroy <christophe.leroy@c-s.fr>
+ *
+ * Common specific routines for the CS Group boards
+ */
+
+#include <fdt_support.h>
+
+static int fdt_set_node_and_value(void *blob, char *node, const char *prop,
+				  void *var, int size)
+{
+	int ret, off;
+
+	off = fdt_path_offset(blob, node);
+
+	if (off < 0) {
+		printf("Cannot find %s node err:%s\n", node, fdt_strerror(off));
+
+		return off;
+	}
+
+	ret = fdt_setprop(blob, off, prop, var, size);
+
+	if (ret < 0)
+		printf("Cannot set %s/%s prop err: %s\n", node, prop, fdt_strerror(ret));
+
+	return ret;
+}
+
+/* Checks front/rear id and remove unneeded nodes from the blob */
+void ft_cleanup(void *blob, unsigned long id, const char *prop, const char *compatible)
+{
+	int off;
+
+	off = fdt_node_offset_by_compatible(blob, -1, compatible);
+
+	while (off != -FDT_ERR_NOTFOUND) {
+		const struct fdt_property *ids;
+		int nb_ids, idx;
+		int tmp = -1;
+
+		ids = fdt_get_property(blob, off, prop, &nb_ids);
+
+		for (idx = 0; idx < nb_ids; idx += 4) {
+			if (*((uint32_t *)&ids->data[idx]) == id)
+				break;
+		}
+
+		if (idx >= nb_ids)
+			fdt_del_node(blob, off);
+		else
+			tmp = off;
+
+		off = fdt_node_offset_by_compatible(blob, tmp, compatible);
+	}
+
+	fdt_set_node_and_value(blob, "/", prop, &id, sizeof(uint32_t));
+}