serial: bfin_sport_uart: shorten the SPORT TX waiting loop

The waiting loop to stop SPORT TX from TX interrupt is too long.  This may
block the SPORT RX interrupts and cause the RX FIFO to overflow. So, do
stop sport TX only after the last char in TX FIFO is moved into the shift
register.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Sonic Zhang 2010-03-09 12:25:29 -05:00 committed by Greg Kroah-Hartman
parent a5a420d207
commit 3f3a978b9f
1 changed files with 7 additions and 1 deletions

View File

@ -271,7 +271,13 @@ static void sport_uart_tx_chars(struct sport_uart_port *up)
}
if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) {
sport_stop_tx(&up->port);
/* The waiting loop to stop SPORT TX from TX interrupt is
* too long. This may block SPORT RX interrupts and cause
* RX FIFO overflow. So, do stop sport TX only after the last
* char in TX FIFO is moved into the shift register.
*/
if (SPORT_GET_STAT(up) & TXHRE)
sport_stop_tx(&up->port);
return;
}