Provided by:
linux-doc-2.6.15_2.6.15-23.39_all 
NAME
uart_get_baud_rate - return baud rate for a particular port
SYNOPSIS
unsigned int uart_get_baud_rate (struct uart_port * port,
struct termios * termios,
struct termios * old,
unsigned int min,
unsigned int max);
ARGUMENTS
port uart_port structure describing the port in question.
termios
desired termios settings.
old old termios (or NULL)
min minimum acceptable baud rate
max maximum acceptable baud rate
DESCRIPTION
Decode the termios structure into a numeric baud rate, taking account
of the magic 38400 baud rate (with spd_* flags), and mapping the B0
rate to 9600 baud.
If the new baud rate is invalid, try the old termios setting. If it’s
still invalid, we try 9600 baud.
Update the termios structure to reflect the baud rate we’re actually
going to be using.