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authorGrant Likely <grant.likely@secretlab.ca>2007-10-23 14:27:46 +1000
committerJosh Boyer <jwboyer@linux.vnet.ibm.com>2007-11-01 07:12:19 -0500
commit1d6b698764084510fe6168bb5b650165dced03ae (patch)
tree3fce7676f8086b0b49d676dcaf99f04a253be989
parent7ae0fa49c6502ca1ada0e043c5d25ee73c0a28c6 (diff)
downloadop-kernel-dev-1d6b698764084510fe6168bb5b650165dced03ae.zip
op-kernel-dev-1d6b698764084510fe6168bb5b650165dced03ae.tar.gz
[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>
-rw-r--r--drivers/serial/uartlite.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/serial/uartlite.c b/drivers/serial/uartlite.c
index dfef83f..a85f2d3 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();
}
}
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