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-rw-r--r--linux-2.6-serial-460800.patch70
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);