From: Sonic Zhang Date: Mon, 19 Nov 2012 06:40:56 +0000 (+0800) Subject: serial: bfin_uart: Don't switch baud rate untill the transfer buffer is empty. X-Git-Tag: firefly_0821_release~3680^2~1518^2~24 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=1cd3f2d2c99892209c4751155ae56ff18b1b253e;p=firefly-linux-kernel-4.4.55.git serial: bfin_uart: Don't switch baud rate untill the transfer buffer is empty. set_termios may be invoked before the former data transfer is completed. Block until the tranfer is done. Signed-off-by: Sonic Zhang Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/tty/serial/bfin_uart.c b/drivers/tty/serial/bfin_uart.c index 18cf45a29d40..e6a008f4939f 100644 --- a/drivers/tty/serial/bfin_uart.c +++ b/drivers/tty/serial/bfin_uart.c @@ -799,6 +799,7 @@ 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: @@ -868,6 +869,14 @@ 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);