[SERIAL] Restrict the baud rates returnable from uart_get_baud_rate()

Supply the old termios, along with the max and min acceptable baud
rate to uart_get_baud_rate().  uart_get_baud_rate() will now try to
find a baud rate that satisfies the max and min constraint out of
(requested rate, old rate, 9600 baud).

We remove the code which performed a similar act in uart_get_divisor()
and pass an appropriate min and max baud rate to uart_get_baud_rate()
based on the UART clock rate.

1 files changed, 3 insertions, 2 deletions

diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 58fe38afbd8e..41b764e48f77 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -280,8 +280,9 @@ void uart_write_wakeup(struct uart_port *port);
  */
 void uart_update_timeout(struct uart_port *port, unsigned int cflag,
 			 unsigned int quot);
-unsigned int uart_get_baud_rate(struct uart_port *port,
-				struct termios *termios);
+unsigned int uart_get_baud_rate(struct uart_port *port, struct termios *termios
+				struct termios *old, unsigned int min,
+				unsigned int max);
 unsigned int uart_get_divisor(struct uart_port *port, struct termios *termios,
 			      struct termios *old_termios);