[PATCH] Exar quad port serial

This is on our "Envoy" boxes which we have, according to the documentation, an
"Exar ST16C554/554D Quad UART with 16-byte Fifo's".  The box also has two
other "on-board" serial ports and a modem chip.

The two on-board serial UARTs were being detected along with the first two
Exar UARTs.  The last two Exar UARTs were not showing up and neither was the
modem.

This patch was the only way I could the kernel to see beyond the standard four
serial ports and get all four of the Exar UARTs to show up.

[[email protected]: build fix]
Signed-off-by:  Paul B Schroeder <[email protected]>
Cc: Lennart Sorensen <[email protected]>
Acked-by: Alan Cox <[email protected]>
Cc: Russell King <[email protected]>
Cc: Greg KH <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

drivers/serial/8250_exar_st16c554.c

@@ -0,0 +1,52 @@
+/*
+ *  linux/drivers/serial/8250_exar.c
+ *
+ *  Written by Paul B Schroeder < pschroeder "at" uplogix "dot" com >
+ *  Based on 8250_boca.
+ *
+ *  Copyright (C) 2005 Russell King.
+ *  Data taken from include/asm-i386/serial.h
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/serial_8250.h>
+
+#define PORT(_base,_irq)				\
+	{						\
+		.iobase		= _base,		\
+		.irq		= _irq,			\
+		.uartclk	= 1843200,		\
+		.iotype		= UPIO_PORT,		\
+		.flags		= UPF_BOOT_AUTOCONF,	\
+	}
+
+static struct plat_serial8250_port exar_data[] = {
+	PORT(0x100, 5),
+	PORT(0x108, 5),
+	PORT(0x110, 5),
+	PORT(0x118, 5),
+	{ },
+};
+
+static struct platform_device exar_device = {
+	.name			= "serial8250",
+	.id			= PLAT8250_DEV_EXAR_ST16C554,
+	.dev			= {
+		.platform_data	= exar_data,
+	},
+};
+
+static int __init exar_init(void)
+{
+	return platform_device_register(&exar_device);
+}
+
+module_init(exar_init);
+
+MODULE_AUTHOR("Paul B Schroeder");
+MODULE_DESCRIPTION("8250 serial probe module for Exar cards");
+MODULE_LICENSE("GPL");

drivers/serial/Kconfig

@@ -210,6 +210,17 @@ config SERIAL_8250_BOCA
 	  To compile this driver as a module, choose M here: the module
 	  will be called 8250_boca.
 
+config SERIAL_8250_EXAR_ST16C554
+	tristate "Support Exar ST16C554/554D Quad UART"
+	depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
+	help
+	  The Uplogix Envoy TU301 uses this Exar Quad UART.  If you are
+	  tinkering with your Envoy TU301, or have a machine with this UART,
+	  say Y here.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called 8250_exar_st16c554.
+
 config SERIAL_8250_HUB6
 	tristate "Support Hub6 cards"
 	depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS

drivers/serial/Makefile

@@ -17,6 +17,7 @@ obj-$(CONFIG_SERIAL_8250_CONSOLE) += 8250_early.o
 obj-$(CONFIG_SERIAL_8250_FOURPORT) += 8250_fourport.o
 obj-$(CONFIG_SERIAL_8250_ACCENT) += 8250_accent.o
 obj-$(CONFIG_SERIAL_8250_BOCA) += 8250_boca.o
+obj-$(CONFIG_SERIAL_8250_EXAR_ST16C554) += 8250_exar_st16c554.o
 obj-$(CONFIG_SERIAL_8250_HUB6) += 8250_hub6.o
 obj-$(CONFIG_SERIAL_8250_MCA) += 8250_mca.o
 obj-$(CONFIG_SERIAL_8250_AU1X00) += 8250_au1x00.o

include/linux/serial_8250.h

@@ -41,6 +41,7 @@ enum {
 	PLAT8250_DEV_FOURPORT,
 	PLAT8250_DEV_ACCENT,
 	PLAT8250_DEV_BOCA,
+	PLAT8250_DEV_EXAR_ST16C554,
 	PLAT8250_DEV_HUB6,
 	PLAT8250_DEV_MCA,
 	PLAT8250_DEV_AU1X00,