diff --git a/drivers/block/ftide020.c b/drivers/block/ftide020.c
index ad8fdad..61900ba 100644
--- a/drivers/block/ftide020.c
+++ b/drivers/block/ftide020.c
@@ -81,7 +81,7 @@
 		IDE_REG_DA_WRITE(port) | val);
 }
 
-void ide_write_data(int dev, ulong *sect_buf, int words)
+void ide_write_data(int dev, const ulong *sect_buf, int words)
 {
 	static struct ftide020_s *ftide020 = (struct ftide020_s *) FTIDE_BASE;