[PATCH 3/6] AMD Geode GX/LX Support (Refreshed)

[Jordan Crouse]

The 5535 has a muxed serial port that can either be used to drive GPIO pins
or a second 16550 UART.  This code enables that UART via a command line
option.
This is most often used with a dongle attached to the VGA port to provide a
a serial port on boards with no dedicated serial goesouta.

Kconfig       |   11 +++++++
Makefile      |    1
cs5535_uart.c |   83 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 95 insertions(+)

Index: linux-2.6.14/drivers/serial/Kconfig
===================================================================
--- linux-2.6.14.orig/drivers/serial/Kconfig
+++ linux-2.6.14/drivers/serial/Kconfig
@@ -608,6 +608,17 @@ config SERIAL_AU1X00_CONSOLE
 	  If you have an Alchemy AU1X00 processor (MIPS based) and you want
 	  to use a console on a serial port, say Y.  Otherwise, say N.
 
+config SERIAL_GEODE_UART2
+	bool "Enable AMD CS5535 UART2 as a serial port"
+	depends on MGEODE_LX
+	default y
+	select SERIAL_CORE
+	help
+	  Select this to allow the user to select the secondary CS5535 UART
+	  as a 16550 serial port instead of the default DDC interface. The
+	  UART2 can be selected by specifying geodeuart2 on the command
+	  line.
+
 config SERIAL_CORE
 	tristate
 
Index: linux-2.6.14/drivers/serial/Makefile
===================================================================
--- linux-2.6.14.orig/drivers/serial/Makefile
+++ linux-2.6.14/drivers/serial/Makefile
@@ -56,3 +56,4 @@ obj-$(CONFIG_SERIAL_JSM) += jsm/
 obj-$(CONFIG_SERIAL_TXX9) += serial_txx9.o
 obj-$(CONFIG_SERIAL_VR41XX) += vr41xx_siu.o
 obj-$(CONFIG_SERIAL_SGI_IOC4) += ioc4_serial.o
+obj-$(CONFIG_SERIAL_GEODE_UART2) += cs5535_uart.o
Index: linux-2.6.14/drivers/serial/cs5535_uart.c
===================================================================
--- /dev/null
+++ linux-2.6.14/drivers/serial/cs5535_uart.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2004-2005 Advanced Micro Devices, Inc.
+ *
+ * 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
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * The full GNU General Public License is included in this distribution in the
+ * file called COPYING
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <asm/msr.h>
+#include <asm/io.h>
+
+/* The CS5535 companion chip has two UARTs.  This code enables the second
+   UART so other devices can use it.  We do it here so we can expose the
+   port early enough for serial debugging
+*/
+
+/* Note - this does not check to see if the CS5535 actually exists */
+
+#define LO(b)  (((1 << b) << 16) | 0x0000)
+#define HI(b)  ((0x0000 << 16) | (1 << b))
+
+static u32 outtab[16] __initdata =
+{
+	0x00,HI(4), 0x04,HI(4), 0x08,HI(4),
+	0x0c,LO(4), 0x10,HI(4), 0x14,LO(4),
+	0x18,LO(4), 0x1C,LO(4)
+};
+
+static u32 intab[16] __initdata = {
+	0x20,HI(3), 0x24,LO(3), 0x28,LO(3),
+	0x2C,LO(3), 0x34,HI(3), 0x38,LO(3),
+     0x40,LO(3), 0x44,LO(3)
+};
+
+static int __init init_cs5535_uart2(char *str)
+{
+	u32 lo = 0, hi = 0;
+	u32 base; u32 i;
+
+	/* Enable UART2 instead of DDC */
+
+	rdmsr(0x51400014, lo, hi);
+	lo &= 0xFF8FFFFF;
+	lo |= 0x00500000;   /* 0x2F8 ttyS1 */
+	wrmsr(0x51400014, lo, hi);
+
+	/* Set up the UART registers */
+	wrmsr(0x5140003E, 0x12, 0x00);
+
+	rdmsr(0x5140000C, lo, hi);
+	base = (u32)(lo & 0xFF00);
+
+	/* Enable the GPIO pins (in and out) */
+
+	for(i = 0; i < 16; i += 2) {
+		outl(outtab[i + 1], base + outtab[i]);
+		outl(intab[i + 1], base + intab[i]);
+	}
+
+	/* Enable the IRQ */
+
+	rdmsr(0x51400021,lo,hi);
+	lo &= 0x0FFFFFFF;
+	lo |= 0x30000000; /* IRQ 3 */
+	wrmsr(0x51400021,lo,hi);
+}
+
+__setup("geodeuart2", init_cs5535_uart2);

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