1 files changed, 70 insertions, 0 deletions
diff --git a/linux-2.6-serial-460800.patch b/linux-2.6-serial-460800.patch
new file mode 100644
index 000000000..17d67ef64
--- /dev/null
+++ b/linux-2.6-serial-460800.patch
@@ -0,0 +1,70 @@
+diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
+index 2209620..659c1bb 100644
+--- a/drivers/serial/8250.c
++++ b/drivers/serial/8250.c
+@@ -7,6 +7,9 @@
+  *
+  *  Copyright (C) 2001 Russell King.
+  *
++ *  2005/09/16: Enabled higher baud rates for 16C95x.
++ *		(Mathias Adam <a2@adamis.de>)
++ *
+  * This program is free software; you can redistribute it and/or modify
+  * it under the terms of the GNU General Public License as published by
+  * the Free Software Foundation; either version 2 of the License, or
+@@ -2227,6 +2230,14 @@ static unsigned int serial8250_get_divisor(struct uart_port *port, unsigned int
+ 	else if ((port->flags & UPF_MAGIC_MULTIPLIER) &&
+ 		 baud == (port->uartclk/8))
+ 		quot = 0x8002;
++	/*
++	 * For 16C950s UART_TCR is used in combination with divisor==1
++	 * to achieve baud rates up to baud_base*4.
++	 */
++	else if ((port->type == PORT_16C950) &&
++		 baud > (port->uartclk/16))
++		quot = 1;
++
+ 	else
+ 		quot = uart_get_divisor(port, baud);
+ 
+@@ -2240,7 +2251,7 @@ serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
+ 	struct uart_8250_port *up = (struct uart_8250_port *)port;
+ 	unsigned char cval, fcr = 0;
+ 	unsigned long flags;
+-	unsigned int baud, quot;
++	unsigned int baud, quot, max_baud;
+ 
+ 	switch (termios->c_cflag & CSIZE) {
+ 	case CS5:
+@@ -2272,9 +2283,10 @@ serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
+ 	/*
+ 	 * Ask the core to calculate the divisor for us.
+ 	 */
++	max_baud = (up->port.type == PORT_16C950 ? port->uartclk/4 : port->uartclk/16);
+ 	baud = uart_get_baud_rate(port, termios, old,
+ 				  port->uartclk / 16 / 0xffff,
+-				  port->uartclk / 16);
++				  max_baud);
+ 	quot = serial8250_get_divisor(port, baud);
+ 
+ 	/*
+@@ -2311,6 +2323,19 @@ serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
+ 	spin_lock_irqsave(&up->port.lock, flags);
+ 
+ 	/*
++	 * 16C950 supports additional prescaler ratios between 1:16 and 1:4
++	 * thus increasing max baud rate to uartclk/4.
++	 */
++	if (up->port.type == PORT_16C950) {
++		if (baud == port->uartclk/4)
++			serial_icr_write(up, UART_TCR, 0x4);
++		else if (baud == port->uartclk/8)
++			serial_icr_write(up, UART_TCR, 0x8);
++		else
++			serial_icr_write(up, UART_TCR, 0);
++	}
++
++	/*
+ 	 * Update the per-port timeout.
+ 	 */
+ 	uart_update_timeout(port, termios->c_cflag, baud);