[POWERPC] Uartlite: speed up console output

Change the wait_tx routine to call cpu_relax() instead of udelay() to
reduce console output latency and test for the TXFULL bit instead of
TXEMPTY.  That way the FIFO doesn't need to by 100% flushed before
writing the next character.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/serial/uartlite.c b/drivers/serial/uartlite.c
index dfef83f14960..a85f2d31a686 100644
--- a/drivers/serial/uartlite.c
+++ b/drivers/serial/uartlite.c
@@ -329,12 +329,14 @@ static struct uart_ops ulite_ops = {
 static void ulite_console_wait_tx(struct uart_port *port)
 {
         int i;
+        u8 val;
 
-        /* wait up to 10ms for the character(s) to be sent */
-        for (i = 0; i < 10000; i++) {
-                if (readb(port->membase + ULITE_STATUS) & ULITE_STATUS_TXEMPTY)
+        /* Spin waiting for TX fifo to have space available */
+        for (i = 0; i < 100000; i++) {
+                val = readb(port->membase + ULITE_STATUS);
+                if ((val & ULITE_STATUS_TXFULL) == 0)
                         break;
-                udelay(1);
+                cpu_relax();
         }
 }