serial8250: DLL/DLM rework, Emma Mobile UART driver

@@ -284,6 +284,66 @@ static const struct serial8250_config ua
 	},
 };
 
+/* Uart divisor latch read */
+static int default_dl_read(struct uart_8250_port *up)
+{
+	return serial_in(up, UART_DLL) | serial_in(up, UART_DLM) << 8;
+}
+
+/* Uart divisor latch write */
+static void default_dl_write(struct uart_8250_port *up, int value)
+{
+	serial_out(up, UART_DLL, value & 0xff);
+	serial_out(up, UART_DLM, value >> 8 & 0xff);
+}
+
+#if defined(CONFIG_MIPS_ALCHEMY)
+/* Au1x00 haven't got a standard divisor latch */
+static int _serial_dl_read(struct uart_8250_port *up)
+{
+	if (up->port.iotype == UPIO_AU)
+		return __raw_readl(up->port.membase + 0x28);
+	else
+		return default_dl_read(up);
+}
+
+static void _serial_dl_write(struct uart_8250_port *up, int value)
+{
+	if (up->port.iotype == UPIO_AU)
+		__raw_writel(value, up->port.membase + 0x28);
+	else
+		default_dl_write(up, value);
+}
+#elif defined(CONFIG_SERIAL_8250_RM9K)
+static int _serial_dl_read(struct uart_8250_port *up)
+{
+	return	(up->port.iotype == UPIO_RM9000) ?
+		(((__raw_readl(up->port.membase + 0x10) << 8) |
+		(__raw_readl(up->port.membase + 0x08) & 0xff)) & 0xffff) :
+		default_dl_read(up);
+}
+
+static void _serial_dl_write(struct uart_8250_port *up, int value)
+{
+	if (up->port.iotype == UPIO_RM9000) {
+		__raw_writel(value, up->port.membase + 0x08);
+		__raw_writel(value >> 8, up->port.membase + 0x10);
+	} else {
+		default_dl_write(up, value);
+	}
+}
+#else
+static int _serial_dl_read(struct uart_8250_port *up)
+{
+	return default_dl_read(up);
+}
+
+static void _serial_dl_write(struct uart_8250_port *up, int value)
+{
+	default_dl_write(up, value);
+}
+#endif
+
 #if defined(CONFIG_MIPS_ALCHEMY)
 
 /* Au1x00 UART hardware has a weird register layout */

@@ -434,6 +494,10 @@ static void set_io_from_upio(struct uart
 {
 	struct uart_8250_port *up =
 		container_of(p, struct uart_8250_port, port);
+
+	up->dl_read = _serial_dl_read;
+	up->dl_write = _serial_dl_write;
+
 	switch (p->iotype) {
 	case UPIO_HUB6:
 		p->serial_in = hub6_serial_in;

@@ -481,59 +545,6 @@ serial_port_out_sync(struct uart_port *p
 	}
 }
 
-/* Uart divisor latch read */
-static inline int _serial_dl_read(struct uart_8250_port *up)
-{
-	return serial_in(up, UART_DLL) | serial_in(up, UART_DLM) << 8;
-}
-
-/* Uart divisor latch write */
-static inline void _serial_dl_write(struct uart_8250_port *up, int value)
-{
-	serial_out(up, UART_DLL, value & 0xff);
-	serial_out(up, UART_DLM, value >> 8 & 0xff);
-}
-
-#if defined(CONFIG_MIPS_ALCHEMY)
-/* Au1x00 haven't got a standard divisor latch */
-static int serial_dl_read(struct uart_8250_port *up)
-{
-	if (up->port.iotype == UPIO_AU)
-		return __raw_readl(up->port.membase + 0x28);
-	else
-		return _serial_dl_read(up);
-}
-
-static void serial_dl_write(struct uart_8250_port *up, int value)
-{
-	if (up->port.iotype == UPIO_AU)
-		__raw_writel(value, up->port.membase + 0x28);
-	else
-		_serial_dl_write(up, value);
-}
-#elif defined(CONFIG_SERIAL_8250_RM9K)
-static int serial_dl_read(struct uart_8250_port *up)
-{
-	return	(up->port.iotype == UPIO_RM9000) ?
-		(((__raw_readl(up->port.membase + 0x10) << 8) |
-		(__raw_readl(up->port.membase + 0x08) & 0xff)) & 0xffff) :
-		_serial_dl_read(up);
-}
-
-static void serial_dl_write(struct uart_8250_port *up, int value)
-{
-	if (up->port.iotype == UPIO_RM9000) {
-		__raw_writel(value, up->port.membase + 0x08);
-		__raw_writel(value >> 8, up->port.membase + 0x10);
-	} else {
-		_serial_dl_write(up, value);
-	}
-}
-#else
-#define serial_dl_read(up) _serial_dl_read(up)
-#define serial_dl_write(up, value) _serial_dl_write(up, value)
-#endif
-
 /*
  * For the 16C950
  */

@@ -37,6 +37,10 @@ struct uart_8250_port {
 	unsigned char		lsr_saved_flags;
 #define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA
 	unsigned char		msr_saved_flags;
+
+	/* 8250 specific callbacks */
+	int			(*dl_read)(struct uart_8250_port *);
+	void			(*dl_write)(struct uart_8250_port *, int);
 };
 
 struct old_serial_port {

@@ -96,6 +100,16 @@ static inline void serial_out(struct uar
 	up->port.serial_out(&up->port, offset, value);
 }
 
+static inline int serial_dl_read(struct uart_8250_port *up)
+{
+	return up->dl_read(up);
+}
+
+static inline void serial_dl_write(struct uart_8250_port *up, int value)
+{
+	up->dl_write(up, value);
+}
+
 #if defined(__alpha__) && !defined(CONFIG_PCI)
 /*
  * Digital did something really horribly wrong with the OUT1 and OUT2

@@ -297,24 +297,7 @@ static void default_dl_write(struct uart
 	serial_out(up, UART_DLM, value >> 8 & 0xff);
 }
 
-#if defined(CONFIG_MIPS_ALCHEMY)
-/* Au1x00 haven't got a standard divisor latch */
-static int _serial_dl_read(struct uart_8250_port *up)
-{
-	if (up->port.iotype == UPIO_AU)
-		return __raw_readl(up->port.membase + 0x28);
-	else
-		return default_dl_read(up);
-}
-
-static void _serial_dl_write(struct uart_8250_port *up, int value)
-{
-	if (up->port.iotype == UPIO_AU)
-		__raw_writel(value, up->port.membase + 0x28);
-	else
-		default_dl_write(up, value);
-}
-#elif defined(CONFIG_SERIAL_8250_RM9K)
+#if defined(CONFIG_SERIAL_8250_RM9K)
 static int _serial_dl_read(struct uart_8250_port *up)
 {
 	return	(up->port.iotype == UPIO_RM9000) ?

@@ -344,7 +327,7 @@ static void _serial_dl_write(struct uart
 }
 #endif
 
-#if defined(CONFIG_MIPS_ALCHEMY)
+#ifdef CONFIG_MIPS_ALCHEMY
 
 /* Au1x00 UART hardware has a weird register layout */
 static const u8 au_io_in_map[] = {

@@ -365,22 +348,32 @@ static const u8 au_io_out_map[] = {
 	[UART_MCR] = 6,
 };
 
-/* sane hardware needs no mapping */
-static inline int map_8250_in_reg(struct uart_port *p, int offset)
+static unsigned int au_serial_in(struct uart_port *p, int offset)
 {
-	if (p->iotype != UPIO_AU)
-		return offset;
-	return au_io_in_map[offset];
+	offset = au_io_in_map[offset] << p->regshift;
+	return __raw_readl(p->membase + offset);
 }
 
-static inline int map_8250_out_reg(struct uart_port *p, int offset)
+static void au_serial_out(struct uart_port *p, int offset, int value)
 {
-	if (p->iotype != UPIO_AU)
-		return offset;
-	return au_io_out_map[offset];
+	offset = au_io_out_map[offset] << p->regshift;
+	__raw_writel(value, p->membase + offset);
+}
+
+/* Au1x00 haven't got a standard divisor latch */
+static int au_serial_dl_read(struct uart_8250_port *up)
+{
+	return __raw_readl(up->port.membase + 0x28);
+}
+
+static void au_serial_dl_write(struct uart_8250_port *up, int value)
+{
+	__raw_writel(value, up->port.membase + 0x28);
 }
 
-#elif defined(CONFIG_SERIAL_8250_RM9K)
+#endif
+
+#if defined(CONFIG_SERIAL_8250_RM9K)
 
 static const u8
 	regmap_in[8] = {

@@ -464,18 +457,6 @@ static unsigned int mem32_serial_in(stru
 	return readl(p->membase + offset);
 }
 
-static unsigned int au_serial_in(struct uart_port *p, int offset)
-{
-	offset = map_8250_in_reg(p, offset) << p->regshift;
-	return __raw_readl(p->membase + offset);
-}
-
-static void au_serial_out(struct uart_port *p, int offset, int value)
-{
-	offset = map_8250_out_reg(p, offset) << p->regshift;
-	__raw_writel(value, p->membase + offset);
-}
-
 static unsigned int io_serial_in(struct uart_port *p, int offset)
 {
 	offset = map_8250_in_reg(p, offset) << p->regshift;

@@ -515,10 +496,14 @@ static void set_io_from_upio(struct uart
 		p->serial_out = mem32_serial_out;
 		break;
 
+#ifdef CONFIG_MIPS_ALCHEMY
 	case UPIO_AU:
 		p->serial_in = au_serial_in;
 		p->serial_out = au_serial_out;
+		up->dl_read = au_serial_dl_read;
+		up->dl_write = au_serial_dl_write;
 		break;
+#endif
 
 	default:
 		p->serial_in = io_serial_in;

@@ -297,25 +297,6 @@ static void default_dl_write(struct uart
 	serial_out(up, UART_DLM, value >> 8 & 0xff);
 }
 
-#if defined(CONFIG_SERIAL_8250_RM9K)
-static int _serial_dl_read(struct uart_8250_port *up)
-{
-	return	(up->port.iotype == UPIO_RM9000) ?
-		(((__raw_readl(up->port.membase + 0x10) << 8) |
-		(__raw_readl(up->port.membase + 0x08) & 0xff)) & 0xffff) :
-		default_dl_read(up);
-}
-
-static void _serial_dl_write(struct uart_8250_port *up, int value)
-{
-	if (up->port.iotype == UPIO_RM9000) {
-		__raw_writel(value, up->port.membase + 0x08);
-		__raw_writel(value >> 8, up->port.membase + 0x10);
-	} else {
-		default_dl_write(up, value);
-	}
-}
-#else
 static int _serial_dl_read(struct uart_8250_port *up)
 {
 	return default_dl_read(up);

@@ -325,7 +306,6 @@ static void _serial_dl_write(struct uart
 {
 	default_dl_write(up, value);
 }
-#endif
 
 #ifdef CONFIG_MIPS_ALCHEMY
 

@@ -373,7 +353,7 @@ static void au_serial_dl_write(struct ua
 
 #endif
 
-#if defined(CONFIG_SERIAL_8250_RM9K)
+#ifdef CONFIG_SERIAL_8250_RM9K
 
 static const u8
 	regmap_in[8] = {

@@ -397,28 +377,36 @@ static const u8
 		[UART_SCR]	= 0x2c
 	};
 
-static inline int map_8250_in_reg(struct uart_port *p, int offset)
+static unsigned int rm9k_serial_in(struct uart_port *p, int offset)
+{
+	offset = regmap_in[offset] << p->regshift;
+	return readl(p->membase + offset);
+}
+
+static void rm9k_serial_out(struct uart_port *p, int offset, int value)
 {
-	if (p->iotype != UPIO_RM9000)
-		return offset;
-	return regmap_in[offset];
+	offset = regmap_out[offset] << p->regshift;
+	writel(value, p->membase + offset);
+}
+
+static int rm9k_serial_dl_read(struct uart_8250_port *up)
+{
+	return ((__raw_readl(up->port.membase + 0x10) << 8) |
+		(__raw_readl(up->port.membase + 0x08) & 0xff)) & 0xffff;
 }
 
-static inline int map_8250_out_reg(struct uart_port *p, int offset)
+static void rm9k_serial_dl_write(struct uart_8250_port *up, int value)
 {
-	if (p->iotype != UPIO_RM9000)
-		return offset;
-	return regmap_out[offset];
+	__raw_writel(value, up->port.membase + 0x08);
+	__raw_writel(value >> 8, up->port.membase + 0x10);
 }
 
-#else
+#endif
 
 /* sane hardware needs no mapping */
 #define map_8250_in_reg(up, offset) (offset)
 #define map_8250_out_reg(up, offset) (offset)
 
-#endif
-
 static unsigned int hub6_serial_in(struct uart_port *p, int offset)
 {
 	offset = map_8250_in_reg(p, offset) << p->regshift;

@@ -490,12 +478,20 @@ static void set_io_from_upio(struct uart
 		p->serial_out = mem_serial_out;
 		break;
 
-	case UPIO_RM9000:
 	case UPIO_MEM32:
 		p->serial_in = mem32_serial_in;
 		p->serial_out = mem32_serial_out;
 		break;
 
+#ifdef CONFIG_SERIAL_8250_RM9K
+	case UPIO_RM9000:
+		p->serial_in = rm9k_serial_in;
+		p->serial_out = rm9k_serial_out;
+		up->dl_read = rm9k_serial_dl_read;
+		up->dl_write = rm9k_serial_dl_write;
+		break;
+#endif
+
 #ifdef CONFIG_MIPS_ALCHEMY
 	case UPIO_AU:
 		p->serial_in = au_serial_in;

@@ -285,28 +285,18 @@ static const struct serial8250_config ua
 };
 
 /* Uart divisor latch read */
-static int default_dl_read(struct uart_8250_port *up)
+static int default_serial_dl_read(struct uart_8250_port *up)
 {
 	return serial_in(up, UART_DLL) | serial_in(up, UART_DLM) << 8;
 }
 
 /* Uart divisor latch write */
-static void default_dl_write(struct uart_8250_port *up, int value)
+static void default_serial_dl_write(struct uart_8250_port *up, int value)
 {
 	serial_out(up, UART_DLL, value & 0xff);
 	serial_out(up, UART_DLM, value >> 8 & 0xff);
 }
 
-static int _serial_dl_read(struct uart_8250_port *up)
-{
-	return default_dl_read(up);
-}
-
-static void _serial_dl_write(struct uart_8250_port *up, int value)
-{
-	default_dl_write(up, value);
-}
-
 #ifdef CONFIG_MIPS_ALCHEMY
 
 /* Au1x00 UART hardware has a weird register layout */

@@ -403,57 +393,53 @@ static void rm9k_serial_dl_write(struct
 
 #endif
 
-/* sane hardware needs no mapping */
-#define map_8250_in_reg(up, offset) (offset)
-#define map_8250_out_reg(up, offset) (offset)
-
 static unsigned int hub6_serial_in(struct uart_port *p, int offset)
 {
-	offset = map_8250_in_reg(p, offset) << p->regshift;
+	offset = offset << p->regshift;
 	outb(p->hub6 - 1 + offset, p->iobase);
 	return inb(p->iobase + 1);
 }
 
 static void hub6_serial_out(struct uart_port *p, int offset, int value)
 {
-	offset = map_8250_out_reg(p, offset) << p->regshift;
+	offset = offset << p->regshift;
 	outb(p->hub6 - 1 + offset, p->iobase);
 	outb(value, p->iobase + 1);
 }
 
 static unsigned int mem_serial_in(struct uart_port *p, int offset)
 {
-	offset = map_8250_in_reg(p, offset) << p->regshift;
+	offset = offset << p->regshift;
 	return readb(p->membase + offset);
 }
 
 static void mem_serial_out(struct uart_port *p, int offset, int value)
 {
-	offset = map_8250_out_reg(p, offset) << p->regshift;
+	offset = offset << p->regshift;
 	writeb(value, p->membase + offset);
 }
 
 static void mem32_serial_out(struct uart_port *p, int offset, int value)
 {
-	offset = map_8250_out_reg(p, offset) << p->regshift;
+	offset = offset << p->regshift;
 	writel(value, p->membase + offset);
 }
 
 static unsigned int mem32_serial_in(struct uart_port *p, int offset)
 {
-	offset = map_8250_in_reg(p, offset) << p->regshift;
+	offset = offset << p->regshift;
 	return readl(p->membase + offset);
 }
 
 static unsigned int io_serial_in(struct uart_port *p, int offset)
 {
-	offset = map_8250_in_reg(p, offset) << p->regshift;
+	offset = offset << p->regshift;
 	return inb(p->iobase + offset);
 }
 
 static void io_serial_out(struct uart_port *p, int offset, int value)
 {
-	offset = map_8250_out_reg(p, offset) << p->regshift;
+	offset = offset << p->regshift;
 	outb(value, p->iobase + offset);
 }
 

@@ -464,8 +450,8 @@ static void set_io_from_upio(struct uart
 	struct uart_8250_port *up =
 		container_of(p, struct uart_8250_port, port);
 
-	up->dl_read = _serial_dl_read;
-	up->dl_write = _serial_dl_write;
+	up->dl_read = default_serial_dl_read;
+	up->dl_write = default_serial_dl_write;
 
 	switch (p->iotype) {
 	case UPIO_HUB6:

@@ -3111,7 +3111,7 @@ static struct uart_8250_port *serial8250
 }
 
 /**
- *	serial8250_register_port - register a serial port
+ *	serial8250_register_8250_port - register a serial port
  *	@port: serial port template
  *
  *	Configure the serial port specified by the request. If the

@@ -3123,52 +3123,56 @@ static struct uart_8250_port *serial8250
  *
  *	On success the port is ready to use and the line number is returned.
  */
-int serial8250_register_port(struct uart_port *port)
+int serial8250_register_8250_port(struct uart_8250_port *up)
 {
 	struct uart_8250_port *uart;
 	int ret = -ENOSPC;
 
-	if (port->uartclk == 0)
+	if (up->port.uartclk == 0)
 		return -EINVAL;
 
 	mutex_lock(&serial_mutex);
 
-	uart = serial8250_find_match_or_unused(port);
+	uart = serial8250_find_match_or_unused(&up->port);
 	if (uart) {
 		uart_remove_one_port(&serial8250_reg, &uart->port);
 
-		uart->port.iobase       = port->iobase;
-		uart->port.membase      = port->membase;
-		uart->port.irq          = port->irq;
-		uart->port.irqflags     = port->irqflags;
-		uart->port.uartclk      = port->uartclk;
-		uart->port.fifosize     = port->fifosize;
-		uart->port.regshift     = port->regshift;
-		uart->port.iotype       = port->iotype;
-		uart->port.flags        = port->flags | UPF_BOOT_AUTOCONF;
-		uart->port.mapbase      = port->mapbase;
-		uart->port.private_data = port->private_data;
-		if (port->dev)
-			uart->port.dev = port->dev;
+		uart->port.iobase       = up->port.iobase;
+		uart->port.membase      = up->port.membase;
+		uart->port.irq          = up->port.irq;
+		uart->port.irqflags     = up->port.irqflags;
+		uart->port.uartclk      = up->port.uartclk;
+		uart->port.fifosize     = up->port.fifosize;
+		uart->port.regshift     = up->port.regshift;
+		uart->port.iotype       = up->port.iotype;
+		uart->port.flags        = up->port.flags | UPF_BOOT_AUTOCONF;
+		uart->port.mapbase      = up->port.mapbase;
+		uart->port.private_data = up->port.private_data;
+		if (up->port.dev)
+			uart->port.dev = up->port.dev;
 
-		if (port->flags & UPF_FIXED_TYPE)
-			serial8250_init_fixed_type_port(uart, port->type);
+		if (up->port.flags & UPF_FIXED_TYPE)
+			serial8250_init_fixed_type_port(uart, up->port.type);
 
 		set_io_from_upio(&uart->port);
 		/* Possibly override default I/O functions.  */
-		if (port->serial_in)
-			uart->port.serial_in = port->serial_in;
-		if (port->serial_out)
-			uart->port.serial_out = port->serial_out;
-		if (port->handle_irq)
-			uart->port.handle_irq = port->handle_irq;
+		if (up->port.serial_in)
+			uart->port.serial_in = up->port.serial_in;
+		if (up->port.serial_out)
+			uart->port.serial_out = up->port.serial_out;
+		if (up->port.handle_irq)
+			uart->port.handle_irq = up->port.handle_irq;
 		/*  Possibly override set_termios call */
-		if (port->set_termios)
-			uart->port.set_termios = port->set_termios;
-		if (port->pm)
-			uart->port.pm = port->pm;
-		if (port->handle_break)
-			uart->port.handle_break = port->handle_break;
+		if (up->port.set_termios)
+			uart->port.set_termios = up->port.set_termios;
+		if (up->port.pm)
+			uart->port.pm = up->port.pm;
+		if (up->port.handle_break)
+			uart->port.handle_break = up->port.handle_break;
+		if (up->dl_read)
+			uart->dl_read = up->dl_read;
+		if (up->dl_write)
+			uart->dl_write = up->dl_write;
 
 		if (serial8250_isa_config != NULL)
 			serial8250_isa_config(0, &uart->port,

@@ -3182,6 +3186,29 @@ int serial8250_register_port(struct uart
 
 	return ret;
 }
+EXPORT_SYMBOL(serial8250_register_8250_port);
+
+/**
+ *	serial8250_register_port - register a serial port
+ *	@port: serial port template
+ *
+ *	Configure the serial port specified by the request. If the
+ *	port exists and is in use, it is hung up and unregistered
+ *	first.
+ *
+ *	The port is then probed and if necessary the IRQ is autodetected
+ *	If this fails an error is returned.
+ *
+ *	On success the port is ready to use and the line number is returned.
+ */
+int serial8250_register_port(struct uart_port *port)
+{
+	struct uart_8250_port up;
+
+	memset(&up, 0, sizeof(up));
+	memcpy(&up.port, port, sizeof(*port));
+	return serial8250_register_8250_port(&up);
+}
 EXPORT_SYMBOL(serial8250_register_port);
 
 /**

@@ -69,6 +69,7 @@ enum {
 struct uart_port;
 struct uart_8250_port;
 
+int serial8250_register_8250_port(struct uart_8250_port *);
 int serial8250_register_port(struct uart_port *);
 void serial8250_unregister_port(int line);
 void serial8250_suspend_port(int line);

@@ -0,0 +1,179 @@
+/*
+ * Renesas Emma Mobile 8250 driver
+ *
+ *  Copyright (C) 2012 Magnus Damm
+ *
+ * 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
+ *
+ * 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
+ */
+
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/serial_8250.h>
+#include <linux/serial_core.h>
+#include <linux/serial_reg.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/slab.h>
+
+#include "8250.h"
+
+#define UART_DLL_EM 9
+#define UART_DLM_EM 10
+
+struct serial8250_em_priv {
+	struct clk *sclk;
+	int line;
+};
+
+static void serial8250_em_serial_out(struct uart_port *p, int offset, int value)
+{
+	switch (offset) {
+	case UART_TX: /* TX @ 0x00 */
+		writeb(value, p->membase);
+		break;
+	case UART_FCR: /* FCR @ 0x0c (+1) */
+	case UART_LCR: /* LCR @ 0x10 (+1) */
+	case UART_MCR: /* MCR @ 0x14 (+1) */
+	case UART_SCR: /* SCR @ 0x20 (+1) */
+		writel(value, p->membase + ((offset + 1) << 2));
+		break;
+	case UART_IER: /* IER @ 0x04 */
+		value &= 0x0f; /* only 4 valid bits - not Xscale */
+		/* fall-through */
+	case UART_DLL_EM: /* DLL @ 0x24 (+9) */
+	case UART_DLM_EM: /* DLM @ 0x28 (+9) */
+		writel(value, p->membase + (offset << 2));
+	}
+}
+
+static unsigned int serial8250_em_serial_in(struct uart_port *p, int offset)
+{
+	switch (offset) {
+	case UART_RX: /* RX @ 0x00 */
+		return readb(p->membase);
+	case UART_MCR: /* MCR @ 0x14 (+1) */
+	case UART_LSR: /* LSR @ 0x18 (+1) */
+	case UART_MSR: /* MSR @ 0x1c (+1) */
+	case UART_SCR: /* SCR @ 0x20 (+1) */
+		return readl(p->membase + ((offset + 1) << 2));
+	case UART_IER: /* IER @ 0x04 */
+	case UART_IIR: /* IIR @ 0x08 */
+	case UART_DLL_EM: /* DLL @ 0x24 (+9) */
+	case UART_DLM_EM: /* DLM @ 0x28 (+9) */
+		return readl(p->membase + (offset << 2));
+	}
+	return 0;
+}
+
+static int serial8250_em_serial_dl_read(struct uart_8250_port *up)
+{
+	return serial_in(up, UART_DLL_EM) | serial_in(up, UART_DLM_EM) << 8;
+}
+
+static void serial8250_em_serial_dl_write(struct uart_8250_port *up, int value)
+{
+	serial_out(up, UART_DLL_EM, value & 0xff);
+	serial_out(up, UART_DLM_EM, value >> 8 & 0xff);
+}
+
+static int __devinit serial8250_em_probe(struct platform_device *pdev)
+{
+	struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	struct serial8250_em_priv *priv;
+	struct uart_8250_port up;
+	int ret = -EINVAL;
+
+	if (!regs || !irq) {
+		dev_err(&pdev->dev, "missing registers or irq\n");
+		goto err0;
+	}
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv) {
+		dev_err(&pdev->dev, "unable to allocate private data\n");
+		ret = -ENOMEM;
+		goto err0;
+	}
+
+	priv->sclk = clk_get(&pdev->dev, "sclk");
+	if (!priv->sclk) {
+		dev_err(&pdev->dev, "unable to get clock\n");
+		goto err1;
+	}
+
+	memset(&up, 0, sizeof(up));
+	up.port.mapbase = regs->start; /* assume 1:1 entity map */
+	up.port.membase = (void __iomem *)regs->start;
+	up.port.irq = irq->start;
+	up.port.type = PORT_UNKNOWN;
+	up.port.flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT;
+	up.port.dev = &pdev->dev;
+	up.port.private_data = priv;
+
+	clk_enable(priv->sclk);
+	up.port.uartclk = clk_get_rate(priv->sclk);
+
+	up.port.iotype = UPIO_MEM32;
+	up.port.serial_in = serial8250_em_serial_in;
+	up.port.serial_out = serial8250_em_serial_out;
+	up.dl_read = serial8250_em_serial_dl_read;
+	up.dl_write = serial8250_em_serial_dl_write;
+
+	ret = serial8250_register_8250_port(&up);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "unable to register 8250 port\n");
+		goto err2;
+	}
+
+	priv->line = ret;
+	platform_set_drvdata(pdev, priv);
+	return 0;
+
+ err2:
+	clk_disable(priv->sclk);
+	clk_put(priv->sclk);
+ err1:
+	kfree(priv);
+ err0:
+	return ret;
+}
+
+static int __devexit serial8250_em_remove(struct platform_device *pdev)
+{
+	struct serial8250_em_priv *priv = platform_get_drvdata(pdev);
+
+	serial8250_unregister_port(priv->line);
+	clk_disable(priv->sclk);
+	clk_put(priv->sclk);
+	kfree(priv);
+	return 0;
+}
+
+static struct platform_driver serial8250_em_platform_driver = {
+	.driver = {
+		.name		= "serial8250-em",
+		.owner		= THIS_MODULE,
+	},
+	.probe			= serial8250_em_probe,
+	.remove			= __devexit_p(serial8250_em_remove),
+};
+
+module_platform_driver(serial8250_em_platform_driver);
+
+MODULE_AUTHOR("Magnus Damm");
+MODULE_DESCRIPTION("Renesas Emma Mobile 8250 Driver");
+MODULE_LICENSE("GPL v2");