[PATCH 01/10] serial: mvebu-uart: initial support for Armada-3700 serial port

[Gregory CLEMENT]

From: Wilson Ding <dingwei@xxxxxxxxxxx>

Armada-3700's uart is a simple serial port, which doesn't
support. Configuring the modem control lines. The uart port has a 32
bytes Tx FIFO and a 64 bytes Rx FIFO

The uart driver implements the uart core operations. It also support the
system (early) console based on Armada-3700's serial port.

Known Issue:

The uart driver currently doesn't support clock programming, which means
the baud-rate stays with the default value configured by the bootloader
at boot time

[gregory.clement@xxxxxxxxxxxxxxxxxx: Rewrite many part which are too long
to enumerate]

Signed-off-by: Wilson Ding <dingwei@xxxxxxxxxxx>
Signed-off-by: Nadav Haklai <nadavh@xxxxxxxxxxx>
Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>
---
 .../devicetree/bindings/tty/serial/mvebu-uart.txt  |  13 +
 Documentation/kernel-parameters.txt                |   6 +
 drivers/tty/serial/Kconfig                         |  22 +
 drivers/tty/serial/Makefile                        |   1 +
 drivers/tty/serial/mvebu-uart.c                    | 649 +++++++++++++++++++++
 include/uapi/linux/serial_core.h                   |   3 +
 6 files changed, 694 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/tty/serial/mvebu-uart.txt
 create mode 100644 drivers/tty/serial/mvebu-uart.c

diff --git a/Documentation/devicetree/bindings/tty/serial/mvebu-uart.txt b/Documentation/devicetree/bindings/tty/serial/mvebu-uart.txt
new file mode 100644
index 000000000000..6087defd9f93
--- /dev/null
+++ b/Documentation/devicetree/bindings/tty/serial/mvebu-uart.txt
@@ -0,0 +1,13 @@
+* Marvell UART : Non standard UART used in some of Marvell EBU SoCs (e.g., Armada-3700)
+
+Required properties:
+- compatible: "marvell,armada-3700-uart"
+- reg: offset and length of the register set for the device.
+- interrupts: device interrupt
+
+Example:
+	serial@12000 {
+		compatible = "marvell,armada-3700-uart";
+		reg = <0x12000 0x400>;
+		interrupts = <43>;
+	};
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 87d40a72f6a1..198f6bd56e84 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1058,6 +1058,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			A valid base address must be provided, and the serial
 			port must already be setup and configured.
 
+		mvebu_uart,<addr>
+			Start an early, polled-mode console on an some mvebu
+			SoC (as the Armada-3700) serial port at the specified
+			address. The serial port must already be setup and
+			configured. Options are not yet supported.
+
 	earlyprintk=	[X86,SH,BLACKFIN,ARM,M68k]
 			earlyprintk=vga
 			earlyprintk=efi
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 39721ec4f415..b291f934d51b 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1606,6 +1606,28 @@ config SERIAL_STM32_CONSOLE
 	depends on SERIAL_STM32=y
 	select SERIAL_CORE_CONSOLE
 
+config SERIAL_MVEBU_UART
+	bool "Marvell EBU serial port support"
+	select SERIAL_CORE
+	help
+	  This driver is for Marvell EBU SoC's UART. If you have a machine
+	  based on the Armada-3700 SoC and wish to use the on-board serial
+	  port,
+	  say 'Y' here.
+	  Otherwise, say 'N'.
+
+config SERIAL_MVEBU_CONSOLE
+	bool "Console on Marvell EBU serial port"
+	depends on SERIAL_MVEBU_UART
+	select SERIAL_CORE_CONSOLE
+	select SERIAL_EARLYCON
+	default y
+	help
+	  Say 'Y' here if you wish to use Armada-3700 UART as the system console.
+	  (the system console is the device which receives all kernel messages
+	  and warnings and which allows logins in single user mode)
+	  Otherwise, say 'N'.
+
 endmenu
 
 config SERIAL_MCTRL_GPIO
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index b391c9b31960..988167595330 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -91,6 +91,7 @@ obj-$(CONFIG_SERIAL_CONEXANT_DIGICOLOR)	+= digicolor-usart.o
 obj-$(CONFIG_SERIAL_MEN_Z135)	+= men_z135_uart.o
 obj-$(CONFIG_SERIAL_SPRD) += sprd_serial.o
 obj-$(CONFIG_SERIAL_STM32)	+= stm32-usart.o
+obj-$(CONFIG_SERIAL_MVEBU_UART)	+= mvebu-uart.o
 
 # GPIOLIB helpers for modem control lines
 obj-$(CONFIG_SERIAL_MCTRL_GPIO)	+= serial_mctrl_gpio.o
diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c
new file mode 100644
index 000000000000..9624070d6058
--- /dev/null
+++ b/drivers/tty/serial/mvebu-uart.c
@@ -0,0 +1,649 @@
+/*
+* ***************************************************************************
+* Copyright (C) 2015 Marvell International Ltd.
+* ***************************************************************************
+* 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 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, see <http://www.gnu.org/licenses/>.
+* ***************************************************************************
+*/
+
+#include <linux/clk.h>
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/serial.h>
+#include <linux/serial_core.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+
+/* Register Map */
+#define UART_RBR		0x00
+#define  RBR_BRK_DET		BIT(15)
+#define  RBR_FRM_ERR_DET	BIT(14)
+#define  RBR_PAR_ERR_DET	BIT(13)
+#define  RBR_OVR_ERR_DET	BIT(12)
+
+#define UART_TSH		0x04
+
+#define UART_CTRL		0x08
+#define  CTRL_SOFT_RST		BIT(31)
+#define  CTRL_TXFIFO_RST	BIT(15)
+#define  CTRL_RXFIFO_RST	BIT(14)
+#define  CTRL_ST_MIRR_EN	BIT(13)
+#define  CTRL_LPBK_EN		BIT(12)
+#define  CTRL_SND_BRK_SEQ	BIT(11)
+#define  CTRL_PAR_EN		BIT(10)
+#define  CTRL_TWO_STOP		BIT(9)
+#define  CTRL_TX_HFL_INT	BIT(8)
+#define  CTRL_RX_HFL_INT	BIT(7)
+#define  CTRL_TX_EMP_INT	BIT(6)
+#define  CTRL_TX_RDY_INT	BIT(5)
+#define  CTRL_RX_RDY_INT	BIT(4)
+#define  CTRL_BRK_DET_INT	BIT(3)
+#define  CTRL_FRM_ERR_INT	BIT(2)
+#define  CTRL_PAR_ERR_INT	BIT(1)
+#define  CTRL_OVR_ERR_INT	BIT(0)
+#define  CTRL_RX_INT			(CTRL_RX_RDY_INT | CTRL_BRK_DET_INT |\
+	CTRL_FRM_ERR_INT | CTRL_PAR_ERR_INT | CTRL_OVR_ERR_INT)
+
+#define UART_STAT		0x0c
+#define  STAT_TX_FIFO_EMP	BIT(13)
+#define  STAT_RX_FIFO_EMP	BIT(12)
+#define  STAT_TX_FIFO_FUL	BIT(11)
+#define  STAT_TX_FIFO_HFL	BIT(10)
+#define  STAT_RX_TOGL		BIT(9)
+#define  STAT_RX_FIFO_FUL	BIT(8)
+#define  STAT_RX_FIFO_HFL	BIT(7)
+#define  STAT_TX_EMP		BIT(6)
+#define  STAT_TX_RDY		BIT(5)
+#define  STAT_RX_RDY		BIT(4)
+#define  STAT_BRK_DET		BIT(3)
+#define  STAT_FRM_ERR		BIT(2)
+#define  STAT_PAR_ERR		BIT(1)
+#define  STAT_OVR_ERR		BIT(0)
+#define  STAT_BRK_ERR		(STAT_BRK_DET | STAT_FRM_ERR | STAT_FRM_ERR\
+				 | STAT_PAR_ERR | STAT_OVR_ERR)
+
+#define UART_BRDV		0x10
+
+#define MVEBU_NR_UARTS		1
+
+#define MVEBU_UART_TYPE		"mvebu-uart"
+
+static struct uart_port mvebu_uart_ports[MVEBU_NR_UARTS];
+
+struct mvebu_uart_data {
+	struct uart_port *port;
+	struct clk       *clk;
+};
+
+/* Core UART Driver Operations */
+static unsigned int mvebu_uart_tx_empty(struct uart_port *port)
+{
+	unsigned long flags;
+	unsigned int st;
+
+	spin_lock_irqsave(&port->lock, flags);
+	st = readl(port->membase + UART_STAT);
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	return (st & STAT_TX_FIFO_EMP) ? TIOCSER_TEMT : 0;
+}
+
+static unsigned int mvebu_uart_get_mctrl(struct uart_port *port)
+{
+	return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
+}
+
+static void mvebu_uart_set_mctrl(struct uart_port *port,
+				 unsigned int mctrl)
+{
+/*
+ * Even if we do not support configuring the modem control lines, this
+ * function must be proided to the serial core
+ */
+}
+
+static void mvebu_uart_stop_tx(struct uart_port *port)
+{
+	unsigned int ctl = readl(port->membase + UART_CTRL);
+
+	ctl &= ~CTRL_TX_RDY_INT;
+	writel(ctl, port->membase + UART_CTRL);
+}
+
+static void mvebu_uart_start_tx(struct uart_port *port)
+{
+	unsigned int ctl = readl(port->membase + UART_CTRL);
+
+	ctl |= CTRL_TX_RDY_INT;
+	writel(ctl, port->membase + UART_CTRL);
+}
+
+static void mvebu_uart_stop_rx(struct uart_port *port)
+{
+	unsigned int ctl = readl(port->membase + UART_CTRL);
+
+	ctl &= ~CTRL_RX_INT;
+	writel(ctl, port->membase + UART_CTRL);
+}
+
+static void mvebu_uart_break_ctl(struct uart_port *port, int brk)
+{
+	unsigned int ctl;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+	ctl = readl(port->membase + UART_CTRL);
+	if (brk == -1)
+		ctl |= CTRL_SND_BRK_SEQ;
+	else
+		ctl &= ~CTRL_SND_BRK_SEQ;
+	writel(ctl, port->membase + UART_CTRL);
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static void mvebu_uart_rx_chars(struct uart_port *port, unsigned int status)
+{
+	struct tty_port *tport = &port->state->port;
+	unsigned char ch = 0;
+	char flag = 0;
+
+	do {
+		if (status & STAT_RX_RDY) {
+			ch = readl(port->membase + UART_RBR);
+			ch &= 0xff;
+			flag = TTY_NORMAL;
+			port->icount.rx++;
+
+			if (status & STAT_PAR_ERR)
+				port->icount.parity++;
+		}
+
+		if (status & STAT_BRK_DET) {
+			port->icount.brk++;
+			status &= ~(STAT_FRM_ERR | STAT_PAR_ERR);
+			if (uart_handle_break(port))
+				goto ignore_char;
+		}
+
+		if (status & STAT_OVR_ERR)
+			port->icount.overrun++;
+
+		if (status & STAT_FRM_ERR)
+			port->icount.frame++;
+
+		if (uart_handle_sysrq_char(port, ch))
+			goto ignore_char;
+
+		if (status & port->ignore_status_mask & STAT_PAR_ERR)
+			status &= ~STAT_RX_RDY;
+
+		status &= port->read_status_mask;
+
+		if (status & STAT_PAR_ERR)
+			flag = TTY_PARITY;
+
+		status &= ~port->ignore_status_mask;
+
+		if (status & STAT_RX_RDY)
+			tty_insert_flip_char(tport, ch, flag);
+
+		if (status & STAT_BRK_DET)
+			tty_insert_flip_char(tport, 0, TTY_BREAK);
+
+		if (status & STAT_FRM_ERR)
+			tty_insert_flip_char(tport, 0, TTY_FRAME);
+
+		if (status & STAT_OVR_ERR)
+			tty_insert_flip_char(tport, 0, TTY_OVERRUN);
+
+ignore_char:
+		status = readl(port->membase + UART_STAT);
+	} while (status & (STAT_RX_RDY | STAT_BRK_DET));
+
+	tty_flip_buffer_push(tport);
+}
+
+static void mvebu_uart_tx_chars(struct uart_port *port, unsigned int status)
+{
+	struct circ_buf *xmit = &port->state->xmit;
+	unsigned int count;
+	unsigned int st;
+
+	if (port->x_char) {
+		writel(port->x_char, port->membase + UART_TSH);
+		port->icount.tx++;
+		port->x_char = 0;
+		return;
+	}
+
+	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
+		mvebu_uart_stop_tx(port);
+		return;
+	}
+
+	for (count = 0; count < port->fifosize; count++) {
+		writel(xmit->buf[xmit->tail], port->membase + UART_TSH);
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		port->icount.tx++;
+
+		if (uart_circ_empty(xmit))
+			break;
+
+		st = readl(port->membase + UART_STAT);
+		if (st & STAT_TX_FIFO_FUL)
+			break;
+	}
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+
+	if (uart_circ_empty(xmit))
+		mvebu_uart_stop_tx(port);
+}
+
+static irqreturn_t mvebu_uart_isr(int irq, void *dev_id)
+{
+	struct uart_port *port = (struct uart_port *)dev_id;
+	unsigned int st = readl(port->membase + UART_STAT);
+
+	if (st & (STAT_RX_RDY | STAT_OVR_ERR | STAT_FRM_ERR | STAT_BRK_DET))
+		mvebu_uart_rx_chars(port, st);
+
+	if (st & STAT_TX_RDY)
+		mvebu_uart_tx_chars(port, st);
+
+	return IRQ_HANDLED;
+}
+
+static int mvebu_uart_startup(struct uart_port *port)
+{
+	int ret;
+
+	writel(CTRL_TXFIFO_RST | CTRL_RXFIFO_RST,
+	       port->membase + UART_CTRL);
+	udelay(1);
+	writel(CTRL_RX_INT, port->membase + UART_CTRL);
+
+	ret = request_irq(port->irq, mvebu_uart_isr, port->irqflags, "serial",
+			  port);
+	if (ret) {
+		dev_err(port->dev, "failed to request irq\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static void mvebu_uart_shutdown(struct uart_port *port)
+{
+	writel(0, port->membase + UART_CTRL);
+}
+
+static void mvebu_uart_set_termios(struct uart_port *port,
+				   struct ktermios *termios,
+				   struct ktermios *old)
+{
+	unsigned long flags;
+	unsigned int baud;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	port->read_status_mask = STAT_RX_RDY | STAT_OVR_ERR |
+		STAT_TX_RDY | STAT_TX_FIFO_FUL;
+
+	if (termios->c_iflag & INPCK)
+		port->read_status_mask |= STAT_FRM_ERR | STAT_PAR_ERR;
+
+	port->ignore_status_mask = 0;
+	if (termios->c_iflag & IGNPAR)
+		port->ignore_status_mask |=
+			STAT_FRM_ERR | STAT_PAR_ERR | STAT_OVR_ERR;
+
+	if ((termios->c_cflag & CREAD) == 0)
+		port->ignore_status_mask |= STAT_RX_RDY | STAT_BRK_ERR;
+
+	baud = uart_get_baud_rate(port, termios, old, 0, 460800);
+	uart_update_timeout(port, termios->c_cflag, baud);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *mvebu_uart_type(struct uart_port *port)
+{
+	return MVEBU_UART_TYPE;
+}
+
+static void mvebu_uart_release_port(struct uart_port *port)
+{
+	/* Nothing to do here */
+}
+
+static int mvebu_uart_request_port(struct uart_port *port)
+{
+	return 0;
+}
+
+#ifdef CONFIG_CONSOLE_POLL
+static int mvebu_uart_get_poll_char(struct uart_port *port)
+{
+	unsigned int st = readl(port->membase + UART_STAT);
+
+	if (!(st & STAT_RX_RDY))
+		return NO_POLL_CHAR;
+
+	return readl(port->membase + UART_RBR);
+}
+
+static void mvebu_uart_put_poll_char(struct uart_port *port, unsigned char c)
+{
+	unsigned int st;
+
+	for (;;) {
+		st = readl(port->membase + UART_STAT);
+
+		if (!(st & STAT_TX_FIFO_FUL))
+			break;
+
+		udelay(1);
+	}
+
+	writel(c, port->membase + UART_TSH);
+}
+#endif
+
+static const struct uart_ops mvebu_uart_ops = {
+	.tx_empty	= mvebu_uart_tx_empty,
+	.set_mctrl	= mvebu_uart_set_mctrl,
+	.get_mctrl	= mvebu_uart_get_mctrl,
+	.stop_tx	= mvebu_uart_stop_tx,
+	.start_tx	= mvebu_uart_start_tx,
+	.stop_rx	= mvebu_uart_stop_rx,
+	.break_ctl	= mvebu_uart_break_ctl,
+	.startup	= mvebu_uart_startup,
+	.shutdown	= mvebu_uart_shutdown,
+	.set_termios	= mvebu_uart_set_termios,
+	.type		= mvebu_uart_type,
+	.release_port	= mvebu_uart_release_port,
+	.request_port	= mvebu_uart_request_port,
+#ifdef CONFIG_CONSOLE_POLL
+	.poll_get_char	= mvebu_uart_get_poll_char,
+	.poll_put_char	= mvebu_uart_put_poll_char,
+#endif
+};
+
+/* Console Driver Operations  */
+
+#ifdef CONFIG_SERIAL_MVEBU_CONSOLE
+/* Early Console */
+static void mvebu_uart_putc(struct uart_port *port, int c)
+{
+	unsigned int st;
+
+	for (;;) {
+		st = readl(port->membase + UART_STAT);
+		if (!(st & STAT_TX_FIFO_FUL))
+			break;
+	}
+
+	writel(c, port->membase + UART_TSH);
+
+	for (;;) {
+		st = readl(port->membase + UART_STAT);
+		if (st & STAT_TX_FIFO_EMP)
+			break;
+	}
+}
+
+static void mvebu_uart_putc_early_write(struct console *con,
+					const char *s,
+					unsigned n)
+{
+	struct earlycon_device *dev = con->data;
+
+	uart_console_write(&dev->port, s, n, mvebu_uart_putc);
+}
+
+static int __init
+mvebu_uart_early_console_setup(struct earlycon_device *device,
+			       const char *opt)
+{
+	if (!device->port.membase)
+		return -ENODEV;
+
+	device->con->write = mvebu_uart_putc_early_write;
+
+	return 0;
+}
+
+EARLYCON_DECLARE(ar3700_uart, mvebu_uart_early_console_setup);
+OF_EARLYCON_DECLARE(ar3700_uart, "marvell,armada-3700-uart",
+		    mvebu_uart_early_console_setup);
+
+static void wait_for_xmitr(struct uart_port *port)
+{
+	u32 val;
+
+	readl_poll_timeout_atomic(port->membase + UART_STAT, val,
+				  (val & STAT_TX_EMP), 1, 10000);
+}
+
+static void mvebu_uart_console_putchar(struct uart_port *port, int ch)
+{
+	wait_for_xmitr(port);
+	writel(ch, port->membase + UART_TSH);
+}
+
+static void mvebu_uart_console_write(struct console *co, const char *s,
+				     unsigned int count)
+{
+	struct uart_port *port = &mvebu_uart_ports[co->index];
+	unsigned long flags;
+	unsigned int ier;
+	int locked = 1;
+
+	if (oops_in_progress)
+		locked = spin_trylock_irqsave(&port->lock, flags);
+	else
+		spin_lock_irqsave(&port->lock, flags);
+
+	ier = readl(port->membase + UART_CTRL) &
+		(CTRL_RX_INT | CTRL_TX_RDY_INT);
+	writel(0, port->membase + UART_CTRL);
+
+	uart_console_write(port, s, count, mvebu_uart_console_putchar);
+
+	wait_for_xmitr(port);
+
+	if (ier)
+		writel(ier, port->membase + UART_CTRL);
+
+	if (locked)
+		spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static int mvebu_uart_console_setup(struct console *co, char *options)
+{
+	struct uart_port *port;
+	int baud = 9600;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+
+	if (co->index < 0 || co->index >= MVEBU_NR_UARTS)
+		return -EINVAL;
+
+	port = &mvebu_uart_ports[co->index];
+
+	if (!port->mapbase || !port->membase) {
+		pr_debug("console on ttyS%i not present\n", co->index);
+		return -ENODEV;
+	}
+
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+	return uart_set_options(port, co, baud, parity, bits, flow);
+}
+
+static struct uart_driver mvebu_uart_driver;
+
+static struct console mvebu_uart_console = {
+	.name	= "ttyS",
+	.write	= mvebu_uart_console_write,
+	.device	= uart_console_device,
+	.setup	= mvebu_uart_console_setup,
+	.flags	= CON_PRINTBUFFER,
+	.index	= -1,
+	.data	= &mvebu_uart_driver,
+};
+
+static int __init mvebu_uart_console_init(void)
+{
+	register_console(&mvebu_uart_console);
+	return 0;
+}
+
+console_initcall(mvebu_uart_console_init);
+
+
+#endif /* CONFIG_SERIAL_MVEBU_CONSOLE */
+
+static struct uart_driver mvebu_uart_driver = {
+	.owner			= THIS_MODULE,
+	.driver_name		= "serial",
+	.dev_name		= "ttyS",
+	.major			= TTY_MAJOR,
+	.minor			= 64,
+	.nr			= MVEBU_NR_UARTS,
+#ifdef CONFIG_SERIAL_MVEBU_CONSOLE
+	.cons			= &mvebu_uart_console,
+#endif
+};
+
+static int mvebu_uart_probe(struct platform_device *pdev)
+{
+	struct resource *reg = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	struct uart_port *port;
+	struct mvebu_uart_data *data;
+	int ret;
+
+	if (!reg || !irq) {
+		dev_err(&pdev->dev, "no registers/irq defined\n");
+		return -EINVAL;
+	}
+
+	port = &mvebu_uart_ports[0];
+
+	spin_lock_init(&port->lock);
+
+	port->dev        = &pdev->dev;
+	port->type       = PORT_MVEBU;
+	port->ops        = &mvebu_uart_ops;
+	port->regshift   = 0;
+
+	port->fifosize   = 32;
+	port->iotype     = UPIO_MEM32;
+	port->flags      = UPF_FIXED_PORT;
+	port->line       = 0; /* single port: force line number to  0 */
+
+	port->irq        = irq->start;
+	port->irqflags   = 0;
+	port->mapbase    = reg->start;
+
+	port->membase = devm_ioremap_resource(&pdev->dev, reg);
+	if (IS_ERR(port->membase))
+		return -PTR_ERR(port->membase);
+
+	data = devm_kzalloc(&pdev->dev, sizeof(struct mvebu_uart_data),
+			    GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->port = port;
+
+	port->private_data = data;
+	platform_set_drvdata(pdev, data);
+
+	ret = uart_add_one_port(&mvebu_uart_driver, port);
+	if (ret)
+		return ret;
+	return 0;
+}
+
+static int mvebu_uart_remove(struct platform_device *pdev)
+{
+	struct mvebu_uart_data *data = platform_get_drvdata(pdev);
+
+	uart_remove_one_port(&mvebu_uart_driver, data->port);
+	data->port->private_data = NULL;
+	data->port->mapbase      = 0;
+	return 0;
+}
+
+/* Match table for of_platform binding */
+static const struct of_device_id mvebu_uart_of_match[] = {
+	{ .compatible = "marvell,armada-3700-uart", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, mvebu_uart_of_match);
+
+static struct platform_driver mvebu_uart_platform_driver = {
+	.probe	= mvebu_uart_probe,
+	.remove	= mvebu_uart_remove,
+	.driver	= {
+		.owner	= THIS_MODULE,
+		.name  = "mvebu-uart",
+		.of_match_table = of_match_ptr(mvebu_uart_of_match),
+	},
+};
+
+static int __init mvebu_uart_init(void)
+{
+	int ret;
+
+	ret = uart_register_driver(&mvebu_uart_driver);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&mvebu_uart_platform_driver);
+	if (ret)
+		uart_unregister_driver(&mvebu_uart_driver);
+
+	return ret;
+}
+
+static void __exit mvebu_uart_exit(void)
+{
+	platform_driver_unregister(&mvebu_uart_platform_driver);
+	uart_unregister_driver(&mvebu_uart_driver);
+}
+
+arch_initcall(mvebu_uart_init);
+module_exit(mvebu_uart_exit);
+
+MODULE_AUTHOR("Wilson Ding <dingwei@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("Marvell Armada-3700 Serial Driver");
+MODULE_LICENSE("GPL");
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
index 3e5d757407fb..e513a4ee369b 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -261,4 +261,7 @@
 /* STM32 USART */
 #define PORT_STM32	113
 
+/* MVEBU UART */
+#define PORT_MVEBU	114
+
 #endif /* _UAPILINUX_SERIAL_CORE_H */
-- 
2.5.0