diff options
| author | Grant Likely <grant.likely@secretlab.ca> | 2007-10-23 14:27:46 +1000 |
|---|---|---|
| committer | Josh Boyer <jwboyer@linux.vnet.ibm.com> | 2007-11-01 07:12:19 -0500 |
| commit | 1d6b698764084510fe6168bb5b650165dced03ae (patch) | |
| tree | 3fce7676f8086b0b49d676dcaf99f04a253be989 | |
| parent | 7ae0fa49c6502ca1ada0e043c5d25ee73c0a28c6 (diff) | |
| download | op-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.c | 10 |
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(); } } |
