From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sonic Zhang Subject: [PATCH 1/2 v2] serial: bfin_uart: Don't switch baud rate untill the transfer buffer is empty. Date: Mon, 19 Nov 2012 14:40:56 +0800 Message-ID: <1353307256-25676-1-git-send-email-sonic.adi@gmail.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from co1ehsobe004.messaging.microsoft.com ([216.32.180.187]:14836 "EHLO co1outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751365Ab2KSGmW (ORCPT ); Mon, 19 Nov 2012 01:42:22 -0500 Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Greg Kroah-Hartman Cc: linux-serial@vger.kernel.org, uclinux-dist-devel@blackfin.uclinux.org, Sonic Zhang From: Sonic Zhang set_termios may be invoked before the former data transfer is completed. Block until the tranfer is done. Signed-off-by: Sonic Zhang --- drivers/tty/serial/bfin_uart.c | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-) diff --git a/drivers/tty/serial/bfin_uart.c b/drivers/tty/serial/bfin_uart.c index 9242d56..f8dc8f1 100644 --- a/drivers/tty/serial/bfin_uart.c +++ b/drivers/tty/serial/bfin_uart.c @@ -800,6 +800,7 @@ bfin_serial_set_termios(struct uart_port *port, struct ktermios *termios, unsigned long flags; unsigned int baud, quot; unsigned int ier, lcr = 0; + unsigned long timeout; switch (termios->c_cflag & CSIZE) { case CS8: @@ -869,6 +870,14 @@ bfin_serial_set_termios(struct uart_port *port, struct ktermios *termios, UART_SET_ANOMALY_THRESHOLD(uart, USEC_PER_SEC / baud * 15); + /* Wait till the transfer buffer is empty */ + timeout = jiffies + msecs_to_jiffies(10); + while (UART_GET_GCTL(uart) & UCEN && !(UART_GET_LSR(uart) & TEMT)) + if (time_after(jiffies, timeout)) { + dev_warn(port->dev, "timeout waiting for TX buffer empty\n"); + break; + } + /* Disable UART */ ier = UART_GET_IER(uart); UART_PUT_GCTL(uart, UART_GET_GCTL(uart) & ~UCEN); -- 1.7.0.4