diff --git a/devices/pl011.c b/devices/pl011.c
index fc94ee3..41f61e9 100644
--- a/devices/pl011.c
+++ b/devices/pl011.c
@@ -18,16 +18,17 @@
     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
+#include <types.h>
+
 #define PL011_SERIAL_BASE 0x10009000
 #define PL011_SERIAL_FLAG_REGISTER 0x18
 #define PL011_SERIAL_BUFFER_FULL (1 << 5)
 
 void pl011_putc(char c)
 {
-    /* Wait until the serial buffer is empty */
-    while (*(volatile unsigned long*)(PL011_SERIAL_BASE + PL011_SERIAL_FLAG_REGISTER)
-		    & (PL011_SERIAL_BUFFER_FULL));
+	/* Wait until the serial buffer is empty */
+	while (*(volatile uint32*)(PL011_SERIAL_BASE + PL011_SERIAL_FLAG_REGISTER) & (PL011_SERIAL_BUFFER_FULL));
 
-    /* When it's empty, put our character at the base */
-    *(volatile unsigned long*)PL011_SERIAL_BASE = c;
+	/* When it's empty, put our character at the base */
+	*(volatile uint32*)PL011_SERIAL_BASE = c;
 }