From: Peter Korsgaard <jacmet@sunsite.dk>

 >> Ok, I can add a wmb(); between.

 Andrew> wmb() won't make that `0' hit the device.  It'll take a
 Andrew> readb() to accomplish that.

Ah yes, the following tiny patch does that:

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Olof Johansson <olof@lixom.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 drivers/serial/uartlite.c |    1 +
 1 files changed, 1 insertion(+)

diff -puN drivers/serial/uartlite.c~serial-uartlite-driver-fix drivers/serial/uartlite.c
--- a/drivers/serial/uartlite.c~serial-uartlite-driver-fix
+++ a/drivers/serial/uartlite.c
@@ -210,6 +210,7 @@ static int ulite_startup(struct uart_por
 static void ulite_shutdown(struct uart_port *port)
 {
 	writeb(0, port->membase + ULITE_CONTROL);
+	readb(port->membase + ULITE_CONTROL); /* dummy */
 	free_irq(port->irq, port);
 }
 
_