serial: Add driver for the Cell Network Processor serial port NWP device

Add support for the nwp serial device which is connected to a DCR bus. It
uses the of_serial device driver to determine necessary properties from
the device tree.  The supported device is added as serial port number 85.

NWP stands for network processor and it is part of the QPACE - Quantum
Chromodynamics Parallel Computing on the Cell Broadband Engine project.
The implementation is a lightweight uart implementation with the focus
to consume as little resources as possible and it is connected to a
DCR bus.
Signed-off-by: Benjamin Krill <ben@codiert.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

drivers/serial/Kconfig

@@ -1320,13 +1320,30 @@ config SERIAL_NETX_CONSOLE
 config SERIAL_OF_PLATFORM
 	tristate "Serial port on Open Firmware platform bus"
 	depends on PPC_OF
-	depends on SERIAL_8250
+	depends on SERIAL_8250 || SERIAL_OF_PLATFORM_NWPSERIAL
 	help
 	  If you have a PowerPC based system that has serial ports
 	  on a platform specific bus, you should enable this option.
 	  Currently, only 8250 compatible ports are supported, but
 	  others can easily be added.
 
+config SERIAL_OF_PLATFORM_NWPSERIAL
+	tristate "NWP serial port driver"
+	depends on PPC_OF && PPC_DCR
+	select SERIAL_OF_PLATFORM
+	select SERIAL_CORE_CONSOLE
+	select SERIAL_CORE
+	help
+	  This driver supports the cell network processor nwp serial
+	  device.
+
+config SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE
+	bool "Console on NWP serial port"
+	depends on SERIAL_OF_PLATFORM_NWPSERIAL=y
+	select SERIAL_CORE_CONSOLE
+	help
+	  Support for Console on the NWP serial ports.
+
 config SERIAL_QE
 	tristate "Freescale QUICC Engine serial port support"
 	depends on QUICC_ENGINE

drivers/serial/Makefile

@@ -72,6 +72,7 @@ obj-$(CONFIG_SERIAL_ATMEL) += atmel_serial.o
 obj-$(CONFIG_SERIAL_UARTLITE) += uartlite.o
 obj-$(CONFIG_SERIAL_NETX) += netx-serial.o
 obj-$(CONFIG_SERIAL_OF_PLATFORM) += of_serial.o
+obj-$(CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL) += nwpserial.o
 obj-$(CONFIG_SERIAL_KS8695) += serial_ks8695.o
 obj-$(CONFIG_KGDB_SERIAL_CONSOLE) += kgdboc.o
 obj-$(CONFIG_SERIAL_QE) += ucc_uart.o

drivers/serial/of_serial.c

@@ -14,6 +14,7 @@
 #include <linux/serial_core.h>
 #include <linux/serial_8250.h>
 #include <linux/of_platform.h>
+#include <linux/nwpserial.h>
 
 #include <asm/prom.h>
 
@@ -99,9 +100,16 @@ static int __devinit of_platform_serial_probe(struct of_device *ofdev,
 		goto out;
 
 	switch (port_type) {
+#ifdef CONFIG_SERIAL_8250
 	case PORT_8250 ... PORT_MAX_8250:
 		ret = serial8250_register_port(&port);
 		break;
+#endif
+#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
+	case PORT_NWPSERIAL:
+		ret = nwpserial_register_port(&port);
+		break;
+#endif
 	default:
 		/* need to add code for these */
 	case PORT_UNKNOWN:
@@ -129,9 +137,16 @@ static int of_platform_serial_remove(struct of_device *ofdev)
 {
 	struct of_serial_info *info = ofdev->dev.driver_data;
 	switch (info->type) {
+#ifdef CONFIG_SERIAL_8250
 	case PORT_8250 ... PORT_MAX_8250:
 		serial8250_unregister_port(info->line);
 		break;
+#endif
+#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
+	case PORT_NWPSERIAL:
+		nwpserial_unregister_port(info->line);
+		break;
+#endif
 	default:
 		/* need to add code for these */
 		break;
@@ -148,6 +163,10 @@ static struct of_device_id __devinitdata of_platform_serial_table[] = {
 	{ .type = "serial", .compatible = "ns16450",  .data = (void *)PORT_16450, },
 	{ .type = "serial", .compatible = "ns16550",  .data = (void *)PORT_16550, },
 	{ .type = "serial", .compatible = "ns16750",  .data = (void *)PORT_16750, },
+#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
+	{ .type = "serial", .compatible = "ibm,qpace-nwp-serial",
+					.data = (void *)PORT_NWPSERIAL, },
+#endif
 	{ .type = "serial",			      .data = (void *)PORT_UNKNOWN, },
 	{ /* end of list */ },
 };

include/linux/nwpserial.h

+/*
+ *  Serial Port driver for a NWP uart device
+ *
+ *    Copyright (C) 2008 IBM Corp., Benjamin Krill <ben@codiert.org>
+ *
+ *  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.
+ *
+ */
+#ifndef _NWPSERIAL_H
+#define _NWPSERIAL_H
+
+int nwpserial_register_port(struct uart_port *port);
+void nwpserial_unregister_port(int line);
+
+#endif /* _NWPSERIAL_H */

include/linux/serial_core.h

@@ -161,6 +161,9 @@
 
 #define PORT_S3C6400	84
 
+/* NWPSERIAL */
+#define PORT_NWPSERIAL	85
+
 #ifdef __KERNEL__
 
 #include <linux/compiler.h>