Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1531 insertions, 0 deletions

diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c
new file mode 100644
index 0000000000..ea924e9b91
--- /dev/null
+++ b/drivers/tty/serial/mvebu-uart.c
@@ -0,0 +1,1531 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+* ***************************************************************************
+* Marvell Armada-3700 Serial Driver
+* Author: Wilson Ding <dingwei@marvell.com>
+* Copyright (C) 2015 Marvell International Ltd.
+* ***************************************************************************
+*/
+
+#include <linux/clk.h>
+#include <linux/clk-provider.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/math64.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_STD_RBR		0x00
+#define UART_EXT_RBR		0x18
+
+#define UART_STD_TSH		0x04
+#define UART_EXT_TSH		0x1C
+
+#define UART_STD_CTRL1		0x08
+#define UART_EXT_CTRL1		0x04
+#define  CTRL_SOFT_RST		BIT(31)
+#define  CTRL_TXFIFO_RST	BIT(15)
+#define  CTRL_RXFIFO_RST	BIT(14)
+#define  CTRL_SND_BRK_SEQ	BIT(11)
+#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_BRK_INT		(CTRL_BRK_DET_INT | CTRL_FRM_ERR_INT | \
+				CTRL_PAR_ERR_INT | CTRL_OVR_ERR_INT)
+
+#define UART_STD_CTRL2		UART_STD_CTRL1
+#define UART_EXT_CTRL2		0x20
+#define  CTRL_STD_TX_RDY_INT	BIT(5)
+#define  CTRL_EXT_TX_RDY_INT	BIT(6)
+#define  CTRL_STD_RX_RDY_INT	BIT(4)
+#define  CTRL_EXT_RX_RDY_INT	BIT(5)
+
+#define UART_STAT		0x0C
+#define  STAT_TX_FIFO_EMP	BIT(13)
+#define  STAT_TX_FIFO_FUL	BIT(11)
+#define  STAT_TX_EMP		BIT(6)
+#define  STAT_STD_TX_RDY	BIT(5)
+#define  STAT_EXT_TX_RDY	BIT(15)
+#define  STAT_STD_RX_RDY	BIT(4)
+#define  STAT_EXT_RX_RDY	BIT(14)
+#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_PAR_ERR | STAT_OVR_ERR)
+
+/*
+ * Marvell Armada 3700 Functional Specifications describes that bit 21 of UART
+ * Clock Control register controls UART1 and bit 20 controls UART2. But in
+ * reality bit 21 controls UART2 and bit 20 controls UART1. This seems to be an
+ * error in Marvell's documentation. Hence following CLK_DIS macros are swapped.
+ */
+
+#define UART_BRDV		0x10
+/* These bits are located in UART1 address space and control UART2 */
+#define  UART2_CLK_DIS		BIT(21)
+/* These bits are located in UART1 address space and control UART1 */
+#define  UART1_CLK_DIS		BIT(20)
+/* These bits are located in UART1 address space and control both UARTs */
+#define  CLK_NO_XTAL		BIT(19)
+#define  CLK_TBG_DIV1_SHIFT	15
+#define  CLK_TBG_DIV1_MASK	0x7
+#define  CLK_TBG_DIV1_MAX	6
+#define  CLK_TBG_DIV2_SHIFT	12
+#define  CLK_TBG_DIV2_MASK	0x7
+#define  CLK_TBG_DIV2_MAX	6
+#define  CLK_TBG_SEL_SHIFT	10
+#define  CLK_TBG_SEL_MASK	0x3
+/* These bits are located in both UARTs address space */
+#define  BRDV_BAUD_MASK         0x3FF
+#define  BRDV_BAUD_MAX		BRDV_BAUD_MASK
+
+#define UART_OSAMP		0x14
+#define  OSAMP_DEFAULT_DIVISOR	16
+#define  OSAMP_DIVISORS_MASK	0x3F3F3F3F
+#define  OSAMP_MAX_DIVISOR	63
+
+#define MVEBU_NR_UARTS		2
+
+#define MVEBU_UART_TYPE		"mvebu-uart"
+#define DRIVER_NAME		"mvebu_serial"
+
+enum {
+	/* Either there is only one summed IRQ... */
+	UART_IRQ_SUM = 0,
+	/* ...or there are two separate IRQ for RX and TX */
+	UART_RX_IRQ = 0,
+	UART_TX_IRQ,
+	UART_IRQ_COUNT
+};
+
+/* Diverging register offsets */
+struct uart_regs_layout {
+	unsigned int rbr;
+	unsigned int tsh;
+	unsigned int ctrl;
+	unsigned int intr;
+};
+
+/* Diverging flags */
+struct uart_flags {
+	unsigned int ctrl_tx_rdy_int;
+	unsigned int ctrl_rx_rdy_int;
+	unsigned int stat_tx_rdy;
+	unsigned int stat_rx_rdy;
+};
+
+/* Driver data, a structure for each UART port */
+struct mvebu_uart_driver_data {
+	bool is_ext;
+	struct uart_regs_layout regs;
+	struct uart_flags flags;
+};
+
+/* Saved registers during suspend */
+struct mvebu_uart_pm_regs {
+	unsigned int rbr;
+	unsigned int tsh;
+	unsigned int ctrl;
+	unsigned int intr;
+	unsigned int stat;
+	unsigned int brdv;
+	unsigned int osamp;
+};
+
+/* MVEBU UART driver structure */
+struct mvebu_uart {
+	struct uart_port *port;
+	struct clk *clk;
+	int irq[UART_IRQ_COUNT];
+	struct mvebu_uart_driver_data *data;
+#if defined(CONFIG_PM)
+	struct mvebu_uart_pm_regs pm_regs;
+#endif /* CONFIG_PM */
+};
+
+static struct mvebu_uart *to_mvuart(struct uart_port *port)
+{
+	return (struct mvebu_uart *)port->private_data;
+}
+
+#define IS_EXTENDED(port) (to_mvuart(port)->data->is_ext)
+
+#define UART_RBR(port) (to_mvuart(port)->data->regs.rbr)
+#define UART_TSH(port) (to_mvuart(port)->data->regs.tsh)
+#define UART_CTRL(port) (to_mvuart(port)->data->regs.ctrl)
+#define UART_INTR(port) (to_mvuart(port)->data->regs.intr)
+
+#define CTRL_TX_RDY_INT(port) (to_mvuart(port)->data->flags.ctrl_tx_rdy_int)
+#define CTRL_RX_RDY_INT(port) (to_mvuart(port)->data->flags.ctrl_rx_rdy_int)
+#define STAT_TX_RDY(port) (to_mvuart(port)->data->flags.stat_tx_rdy)
+#define STAT_RX_RDY(port) (to_mvuart(port)->data->flags.stat_rx_rdy)
+
+static struct uart_port mvebu_uart_ports[MVEBU_NR_UARTS];
+
+static DEFINE_SPINLOCK(mvebu_uart_lock);
+
+/* 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_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_INTR(port));
+
+	ctl &= ~CTRL_TX_RDY_INT(port);
+	writel(ctl, port->membase + UART_INTR(port));
+}
+
+static void mvebu_uart_start_tx(struct uart_port *port)
+{
+	unsigned int ctl;
+	struct circ_buf *xmit = &port->state->xmit;
+
+	if (IS_EXTENDED(port) && !uart_circ_empty(xmit)) {
+		writel(xmit->buf[xmit->tail], port->membase + UART_TSH(port));
+		uart_xmit_advance(port, 1);
+	}
+
+	ctl = readl(port->membase + UART_INTR(port));
+	ctl |= CTRL_TX_RDY_INT(port);
+	writel(ctl, port->membase + UART_INTR(port));
+}
+
+static void mvebu_uart_stop_rx(struct uart_port *port)
+{
+	unsigned int ctl;
+
+	ctl = readl(port->membase + UART_CTRL(port));
+	ctl &= ~CTRL_BRK_INT;
+	writel(ctl, port->membase + UART_CTRL(port));
+
+	ctl = readl(port->membase + UART_INTR(port));
+	ctl &= ~CTRL_RX_RDY_INT(port);
+	writel(ctl, port->membase + UART_INTR(port));
+}
+
+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(port));
+	if (brk == -1)
+		ctl |= CTRL_SND_BRK_SEQ;
+	else
+		ctl &= ~CTRL_SND_BRK_SEQ;
+	writel(ctl, port->membase + UART_CTRL(port));
+	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;
+	int ret;
+
+	do {
+		if (status & STAT_RX_RDY(port)) {
+			ch = readl(port->membase + UART_RBR(port));
+			ch &= 0xff;
+			flag = TTY_NORMAL;
+			port->icount.rx++;
+
+			if (status & STAT_PAR_ERR)
+				port->icount.parity++;
+		}
+
+		/*
+		 * For UART2, error bits are not cleared on buffer read.
+		 * This causes interrupt loop and system hang.
+		 */
+		if (IS_EXTENDED(port) && (status & STAT_BRK_ERR)) {
+			ret = readl(port->membase + UART_STAT);
+			ret |= STAT_BRK_ERR;
+			writel(ret, port->membase + UART_STAT);
+		}
+
+		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(port);
+
+		status &= port->read_status_mask;
+
+		if (status & STAT_PAR_ERR)
+			flag = TTY_PARITY;
+
+		status &= ~port->ignore_status_mask;
+
+		if (status & STAT_RX_RDY(port))
+			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(port) | STAT_BRK_DET));
+
+	tty_flip_buffer_push(tport);
+}
+
+static void mvebu_uart_tx_chars(struct uart_port *port, unsigned int status)
+{
+	u8 ch;
+
+	uart_port_tx_limited(port, ch, port->fifosize,
+		!(readl(port->membase + UART_STAT) & STAT_TX_FIFO_FUL),
+		writel(ch, port->membase + UART_TSH(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(port) | STAT_OVR_ERR | STAT_FRM_ERR |
+		  STAT_BRK_DET))
+		mvebu_uart_rx_chars(port, st);
+
+	if (st & STAT_TX_RDY(port))
+		mvebu_uart_tx_chars(port, st);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t mvebu_uart_rx_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(port) | STAT_OVR_ERR | STAT_FRM_ERR |
+			STAT_BRK_DET))
+		mvebu_uart_rx_chars(port, st);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t mvebu_uart_tx_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_TX_RDY(port))
+		mvebu_uart_tx_chars(port, st);
+
+	return IRQ_HANDLED;
+}
+
+static int mvebu_uart_startup(struct uart_port *port)
+{
+	struct mvebu_uart *mvuart = to_mvuart(port);
+	unsigned int ctl;
+	int ret;
+
+	writel(CTRL_TXFIFO_RST | CTRL_RXFIFO_RST,
+	       port->membase + UART_CTRL(port));
+	udelay(1);
+
+	/* Clear the error bits of state register before IRQ request */
+	ret = readl(port->membase + UART_STAT);
+	ret |= STAT_BRK_ERR;
+	writel(ret, port->membase + UART_STAT);
+
+	writel(CTRL_BRK_INT, port->membase + UART_CTRL(port));
+
+	ctl = readl(port->membase + UART_INTR(port));
+	ctl |= CTRL_RX_RDY_INT(port);
+	writel(ctl, port->membase + UART_INTR(port));
+
+	if (!mvuart->irq[UART_TX_IRQ]) {
+		/* Old bindings with just one interrupt (UART0 only) */
+		ret = devm_request_irq(port->dev, mvuart->irq[UART_IRQ_SUM],
+				       mvebu_uart_isr, port->irqflags,
+				       dev_name(port->dev), port);
+		if (ret) {
+			dev_err(port->dev, "unable to request IRQ %d\n",
+				mvuart->irq[UART_IRQ_SUM]);
+			return ret;
+		}
+	} else {
+		/* New bindings with an IRQ for RX and TX (both UART) */
+		ret = devm_request_irq(port->dev, mvuart->irq[UART_RX_IRQ],
+				       mvebu_uart_rx_isr, port->irqflags,
+				       dev_name(port->dev), port);
+		if (ret) {
+			dev_err(port->dev, "unable to request IRQ %d\n",
+				mvuart->irq[UART_RX_IRQ]);
+			return ret;
+		}
+
+		ret = devm_request_irq(port->dev, mvuart->irq[UART_TX_IRQ],
+				       mvebu_uart_tx_isr, port->irqflags,
+				       dev_name(port->dev),
+				       port);
+		if (ret) {
+			dev_err(port->dev, "unable to request IRQ %d\n",
+				mvuart->irq[UART_TX_IRQ]);
+			devm_free_irq(port->dev, mvuart->irq[UART_RX_IRQ],
+				      port);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static void mvebu_uart_shutdown(struct uart_port *port)
+{
+	struct mvebu_uart *mvuart = to_mvuart(port);
+
+	writel(0, port->membase + UART_INTR(port));
+
+	if (!mvuart->irq[UART_TX_IRQ]) {
+		devm_free_irq(port->dev, mvuart->irq[UART_IRQ_SUM], port);
+	} else {
+		devm_free_irq(port->dev, mvuart->irq[UART_RX_IRQ], port);
+		devm_free_irq(port->dev, mvuart->irq[UART_TX_IRQ], port);
+	}
+}
+
+static unsigned int mvebu_uart_baud_rate_set(struct uart_port *port, unsigned int baud)
+{
+	unsigned int d_divisor, m_divisor;
+	unsigned long flags;
+	u32 brdv, osamp;
+
+	if (!port->uartclk)
+		return 0;
+
+	/*
+	 * The baudrate is derived from the UART clock thanks to divisors:
+	 *   > d1 * d2 ("TBG divisors"): can divide only TBG clock from 1 to 6
+	 *   > D ("baud generator"): can divide the clock from 1 to 1023
+	 *   > M ("fractional divisor"): allows a better accuracy (from 1 to 63)
+	 *
+	 * Exact formulas for calculating baudrate:
+	 *
+	 * with default x16 scheme:
+	 *   baudrate = xtal / (d * 16)
+	 *   baudrate = tbg / (d1 * d2 * d * 16)
+	 *
+	 * with fractional divisor:
+	 *   baudrate = 10 * xtal / (d * (3 * (m1 + m2) + 2 * (m3 + m4)))
+	 *   baudrate = 10 * tbg / (d1*d2 * d * (3 * (m1 + m2) + 2 * (m3 + m4)))
+	 *
+	 * Oversampling value:
+	 *   osamp = (m1 << 0) | (m2 << 8) | (m3 << 16) | (m4 << 24);
+	 *
+	 * Where m1 controls number of clock cycles per bit for bits 1,2,3;
+	 * m2 for bits 4,5,6; m3 for bits 7,8 and m4 for bits 9,10.
+	 *
+	 * To simplify baudrate setup set all the M prescalers to the same
+	 * value. For baudrates 9600 Bd and higher, it is enough to use the
+	 * default (x16) divisor or fractional divisor with M = 63, so there
+	 * is no need to use real fractional support (where the M prescalers
+	 * are not equal).
+	 *
+	 * When all the M prescalers are zeroed then default (x16) divisor is
+	 * used. Default x16 scheme is more stable than M (fractional divisor),
+	 * so use M only when D divisor is not enough to derive baudrate.
+	 *
+	 * Member port->uartclk is either xtal clock rate or TBG clock rate
+	 * divided by (d1 * d2). So d1 and d2 are already set by the UART clock
+	 * driver (and UART driver itself cannot change them). Moreover they are
+	 * shared between both UARTs.
+	 */
+
+	m_divisor = OSAMP_DEFAULT_DIVISOR;
+	d_divisor = DIV_ROUND_CLOSEST(port->uartclk, baud * m_divisor);
+
+	if (d_divisor > BRDV_BAUD_MAX) {
+		/*
+		 * Experiments show that small M divisors are unstable.
+		 * Use maximal possible M = 63 and calculate D divisor.
+		 */
+		m_divisor = OSAMP_MAX_DIVISOR;
+		d_divisor = DIV_ROUND_CLOSEST(port->uartclk, baud * m_divisor);
+	}
+
+	if (d_divisor < 1)
+		d_divisor = 1;
+	else if (d_divisor > BRDV_BAUD_MAX)
+		d_divisor = BRDV_BAUD_MAX;
+
+	spin_lock_irqsave(&mvebu_uart_lock, flags);
+	brdv = readl(port->membase + UART_BRDV);
+	brdv &= ~BRDV_BAUD_MASK;
+	brdv |= d_divisor;
+	writel(brdv, port->membase + UART_BRDV);
+	spin_unlock_irqrestore(&mvebu_uart_lock, flags);
+
+	osamp = readl(port->membase + UART_OSAMP);
+	osamp &= ~OSAMP_DIVISORS_MASK;
+	if (m_divisor != OSAMP_DEFAULT_DIVISOR)
+		osamp |= (m_divisor << 0) | (m_divisor << 8) |
+			(m_divisor << 16) | (m_divisor << 24);
+	writel(osamp, port->membase + UART_OSAMP);
+
+	return DIV_ROUND_CLOSEST(port->uartclk, d_divisor * m_divisor);
+}
+
+static void mvebu_uart_set_termios(struct uart_port *port,
+				   struct ktermios *termios,
+				   const struct ktermios *old)
+{
+	unsigned long flags;
+	unsigned int baud, min_baud, max_baud;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	port->read_status_mask = STAT_RX_RDY(port) | STAT_OVR_ERR |
+		STAT_TX_RDY(port) | 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(port) | STAT_BRK_ERR;
+
+	/*
+	 * Maximal divisor is 1023 and maximal fractional divisor is 63. And
+	 * experiments show that baudrates above 1/80 of parent clock rate are
+	 * not stable. So disallow baudrates above 1/80 of the parent clock
+	 * rate. If port->uartclk is not available, then
+	 * mvebu_uart_baud_rate_set() fails, so values min_baud and max_baud
+	 * in this case do not matter.
+	 */
+	min_baud = DIV_ROUND_UP(port->uartclk, BRDV_BAUD_MAX *
+				OSAMP_MAX_DIVISOR);
+	max_baud = port->uartclk / 80;
+
+	baud = uart_get_baud_rate(port, termios, old, min_baud, max_baud);
+	baud = mvebu_uart_baud_rate_set(port, baud);
+
+	/* In case baudrate cannot be changed, report previous old value */
+	if (baud == 0 && old)
+		baud = tty_termios_baud_rate(old);
+
+	/* Only the following flag changes are supported */
+	if (old) {
+		termios->c_iflag &= INPCK | IGNPAR;
+		termios->c_iflag |= old->c_iflag & ~(INPCK | IGNPAR);
+		termios->c_cflag &= CREAD | CBAUD;
+		termios->c_cflag |= old->c_cflag & ~(CREAD | CBAUD);
+		termios->c_cflag |= CS8;
+	}
+
+	if (baud != 0) {
+		tty_termios_encode_baud_rate(termios, baud, baud);
+		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(port)))
+		return NO_POLL_CHAR;
+
+	return readl(port->membase + UART_RBR(port));
+}
+
+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(port));
+}
+#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, unsigned char c)
+{
+	unsigned int st;
+
+	for (;;) {
+		st = readl(port->membase + UART_STAT);
+		if (!(st & STAT_TX_FIFO_FUL))
+			break;
+	}
+
+	/* At early stage, DT is not parsed yet, only use UART0 */
+	writel(c, port->membase + UART_STD_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 int 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_RDY(port)), 1, 10000);
+}
+
+static void wait_for_xmite(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, unsigned char ch)
+{
+	wait_for_xmitr(port);
+	writel(ch, port->membase + UART_TSH(port));
+}
+
+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, intr, ctl;
+	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(port)) & CTRL_BRK_INT;
+	intr = readl(port->membase + UART_INTR(port)) &
+		(CTRL_RX_RDY_INT(port) | CTRL_TX_RDY_INT(port));
+	writel(0, port->membase + UART_CTRL(port));
+	writel(0, port->membase + UART_INTR(port));
+
+	uart_console_write(port, s, count, mvebu_uart_console_putchar);
+
+	wait_for_xmite(port);
+
+	if (ier)
+		writel(ier, port->membase + UART_CTRL(port));
+
+	if (intr) {
+		ctl = intr | readl(port->membase + UART_INTR(port));
+		writel(ctl, port->membase + UART_INTR(port));
+	}
+
+	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 ttyMV%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	= "ttyMV",
+	.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		= DRIVER_NAME,
+	.dev_name		= "ttyMV",
+	.nr			= MVEBU_NR_UARTS,
+#ifdef CONFIG_SERIAL_MVEBU_CONSOLE
+	.cons			= &mvebu_uart_console,
+#endif
+};
+
+#if defined(CONFIG_PM)
+static int mvebu_uart_suspend(struct device *dev)
+{
+	struct mvebu_uart *mvuart = dev_get_drvdata(dev);
+	struct uart_port *port = mvuart->port;
+	unsigned long flags;
+
+	uart_suspend_port(&mvebu_uart_driver, port);
+
+	mvuart->pm_regs.rbr = readl(port->membase + UART_RBR(port));
+	mvuart->pm_regs.tsh = readl(port->membase + UART_TSH(port));
+	mvuart->pm_regs.ctrl = readl(port->membase + UART_CTRL(port));
+	mvuart->pm_regs.intr = readl(port->membase + UART_INTR(port));
+	mvuart->pm_regs.stat = readl(port->membase + UART_STAT);
+	spin_lock_irqsave(&mvebu_uart_lock, flags);
+	mvuart->pm_regs.brdv = readl(port->membase + UART_BRDV);
+	spin_unlock_irqrestore(&mvebu_uart_lock, flags);
+	mvuart->pm_regs.osamp = readl(port->membase + UART_OSAMP);
+
+	device_set_wakeup_enable(dev, true);
+
+	return 0;
+}
+
+static int mvebu_uart_resume(struct device *dev)
+{
+	struct mvebu_uart *mvuart = dev_get_drvdata(dev);
+	struct uart_port *port = mvuart->port;
+	unsigned long flags;
+
+	writel(mvuart->pm_regs.rbr, port->membase + UART_RBR(port));
+	writel(mvuart->pm_regs.tsh, port->membase + UART_TSH(port));
+	writel(mvuart->pm_regs.ctrl, port->membase + UART_CTRL(port));
+	writel(mvuart->pm_regs.intr, port->membase + UART_INTR(port));
+	writel(mvuart->pm_regs.stat, port->membase + UART_STAT);
+	spin_lock_irqsave(&mvebu_uart_lock, flags);
+	writel(mvuart->pm_regs.brdv, port->membase + UART_BRDV);
+	spin_unlock_irqrestore(&mvebu_uart_lock, flags);
+	writel(mvuart->pm_regs.osamp, port->membase + UART_OSAMP);
+
+	uart_resume_port(&mvebu_uart_driver, port);
+
+	return 0;
+}
+
+static const struct dev_pm_ops mvebu_uart_pm_ops = {
+	.suspend        = mvebu_uart_suspend,
+	.resume         = mvebu_uart_resume,
+};
+#endif /* CONFIG_PM */
+
+static const struct of_device_id mvebu_uart_of_match[];
+
+/* Counter to keep track of each UART port id when not using CONFIG_OF */
+static int uart_num_counter;
+
+static int mvebu_uart_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *match = of_match_device(mvebu_uart_of_match,
+							   &pdev->dev);
+	struct uart_port *port;
+	struct mvebu_uart *mvuart;
+	struct resource *reg;
+	int id, irq;
+
+	/* Assume that all UART ports have a DT alias or none has */
+	id = of_alias_get_id(pdev->dev.of_node, "serial");
+	if (!pdev->dev.of_node || id < 0)
+		pdev->id = uart_num_counter++;
+	else
+		pdev->id = id;
+
+	if (pdev->id >= MVEBU_NR_UARTS) {
+		dev_err(&pdev->dev, "cannot have more than %d UART ports\n",
+			MVEBU_NR_UARTS);
+		return -EINVAL;
+	}
+
+	port = &mvebu_uart_ports[pdev->id];
+
+	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       = pdev->id;
+
+	/*
+	 * IRQ number is not stored in this structure because we may have two of
+	 * them per port (RX and TX). Instead, use the driver UART structure
+	 * array so called ->irq[].
+	 */
+	port->irq        = 0;
+	port->irqflags   = 0;
+
+	port->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &reg);
+	if (IS_ERR(port->membase))
+		return PTR_ERR(port->membase);
+	port->mapbase    = reg->start;
+
+	mvuart = devm_kzalloc(&pdev->dev, sizeof(struct mvebu_uart),
+			      GFP_KERNEL);
+	if (!mvuart)
+		return -ENOMEM;
+
+	/* Get controller data depending on the compatible string */
+	mvuart->data = (struct mvebu_uart_driver_data *)match->data;
+	mvuart->port = port;
+
+	port->private_data = mvuart;
+	platform_set_drvdata(pdev, mvuart);
+
+	/* Get fixed clock frequency */
+	mvuart->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(mvuart->clk)) {
+		if (PTR_ERR(mvuart->clk) == -EPROBE_DEFER)
+			return PTR_ERR(mvuart->clk);
+
+		if (IS_EXTENDED(port)) {
+			dev_err(&pdev->dev, "unable to get UART clock\n");
+			return PTR_ERR(mvuart->clk);
+		}
+	} else {
+		if (!clk_prepare_enable(mvuart->clk))
+			port->uartclk = clk_get_rate(mvuart->clk);
+	}
+
+	/* Manage interrupts */
+	if (platform_irq_count(pdev) == 1) {
+		/* Old bindings: no name on the single unamed UART0 IRQ */
+		irq = platform_get_irq(pdev, 0);
+		if (irq < 0)
+			return irq;
+
+		mvuart->irq[UART_IRQ_SUM] = irq;
+	} else {
+		/*
+		 * New bindings: named interrupts (RX, TX) for both UARTS,
+		 * only make use of uart-rx and uart-tx interrupts, do not use
+		 * uart-sum of UART0 port.
+		 */
+		irq = platform_get_irq_byname(pdev, "uart-rx");
+		if (irq < 0)
+			return irq;
+
+		mvuart->irq[UART_RX_IRQ] = irq;
+
+		irq = platform_get_irq_byname(pdev, "uart-tx");
+		if (irq < 0)
+			return irq;
+
+		mvuart->irq[UART_TX_IRQ] = irq;
+	}
+
+	/* UART Soft Reset*/
+	writel(CTRL_SOFT_RST, port->membase + UART_CTRL(port));
+	udelay(1);
+	writel(0, port->membase + UART_CTRL(port));
+
+	return uart_add_one_port(&mvebu_uart_driver, port);
+}
+
+static struct mvebu_uart_driver_data uart_std_driver_data = {
+	.is_ext = false,
+	.regs.rbr = UART_STD_RBR,
+	.regs.tsh = UART_STD_TSH,
+	.regs.ctrl = UART_STD_CTRL1,
+	.regs.intr = UART_STD_CTRL2,
+	.flags.ctrl_tx_rdy_int = CTRL_STD_TX_RDY_INT,
+	.flags.ctrl_rx_rdy_int = CTRL_STD_RX_RDY_INT,
+	.flags.stat_tx_rdy = STAT_STD_TX_RDY,
+	.flags.stat_rx_rdy = STAT_STD_RX_RDY,
+};
+
+static struct mvebu_uart_driver_data uart_ext_driver_data = {
+	.is_ext = true,
+	.regs.rbr = UART_EXT_RBR,
+	.regs.tsh = UART_EXT_TSH,
+	.regs.ctrl = UART_EXT_CTRL1,
+	.regs.intr = UART_EXT_CTRL2,
+	.flags.ctrl_tx_rdy_int = CTRL_EXT_TX_RDY_INT,
+	.flags.ctrl_rx_rdy_int = CTRL_EXT_RX_RDY_INT,
+	.flags.stat_tx_rdy = STAT_EXT_TX_RDY,
+	.flags.stat_rx_rdy = STAT_EXT_RX_RDY,
+};
+
+/* Match table for of_platform binding */
+static const struct of_device_id mvebu_uart_of_match[] = {
+	{
+		.compatible = "marvell,armada-3700-uart",
+		.data = (void *)&uart_std_driver_data,
+	},
+	{
+		.compatible = "marvell,armada-3700-uart-ext",
+		.data = (void *)&uart_ext_driver_data,
+	},
+	{}
+};
+
+static struct platform_driver mvebu_uart_platform_driver = {
+	.probe	= mvebu_uart_probe,
+	.driver	= {
+		.name  = "mvebu-uart",
+		.of_match_table = of_match_ptr(mvebu_uart_of_match),
+		.suppress_bind_attrs = true,
+#if defined(CONFIG_PM)
+		.pm	= &mvebu_uart_pm_ops,
+#endif /* CONFIG_PM */
+	},
+};
+
+/* This code is based on clk-fixed-factor.c driver and modified. */
+
+struct mvebu_uart_clock {
+	struct clk_hw clk_hw;
+	int clock_idx;
+	u32 pm_context_reg1;
+	u32 pm_context_reg2;
+};
+
+struct mvebu_uart_clock_base {
+	struct mvebu_uart_clock clocks[2];
+	unsigned int parent_rates[5];
+	int parent_idx;
+	unsigned int div;
+	void __iomem *reg1;
+	void __iomem *reg2;
+	bool configured;
+};
+
+#define PARENT_CLOCK_XTAL 4
+
+#define to_uart_clock(hw) container_of(hw, struct mvebu_uart_clock, clk_hw)
+#define to_uart_clock_base(uart_clock) container_of(uart_clock, \
+	struct mvebu_uart_clock_base, clocks[uart_clock->clock_idx])
+
+static int mvebu_uart_clock_prepare(struct clk_hw *hw)
+{
+	struct mvebu_uart_clock *uart_clock = to_uart_clock(hw);
+	struct mvebu_uart_clock_base *uart_clock_base =
+						to_uart_clock_base(uart_clock);
+	unsigned int prev_clock_idx, prev_clock_rate, prev_d1d2;
+	unsigned int parent_clock_idx, parent_clock_rate;
+	unsigned long flags;
+	unsigned int d1, d2;
+	u64 divisor;
+	u32 val;
+
+	/*
+	 * This function just reconfigures UART Clock Control register (located
+	 * in UART1 address space which controls both UART1 and UART2) to
+	 * selected UART base clock and recalculates current UART1/UART2
+	 * divisors in their address spaces, so that final baudrate will not be
+	 * changed by switching UART parent clock. This is required for
+	 * otherwise kernel's boot log stops working - we need to ensure that
+	 * UART baudrate does not change during this setup. It is a one time
+	 * operation, it will execute only once and set `configured` to true,
+	 * and be skipped on subsequent calls. Because this UART Clock Control
+	 * register (UART_BRDV) is shared between UART1 baudrate function,
+	 * UART1 clock selector and UART2 clock selector, every access to
+	 * UART_BRDV (reg1) needs to be protected by a lock.
+	 */
+
+	spin_lock_irqsave(&mvebu_uart_lock, flags);
+
+	if (uart_clock_base->configured) {
+		spin_unlock_irqrestore(&mvebu_uart_lock, flags);
+		return 0;
+	}
+
+	parent_clock_idx = uart_clock_base->parent_idx;
+	parent_clock_rate = uart_clock_base->parent_rates[parent_clock_idx];
+
+	val = readl(uart_clock_base->reg1);
+
+	if (uart_clock_base->div > CLK_TBG_DIV1_MAX) {
+		d1 = CLK_TBG_DIV1_MAX;
+		d2 = uart_clock_base->div / CLK_TBG_DIV1_MAX;
+	} else {
+		d1 = uart_clock_base->div;
+		d2 = 1;
+	}
+
+	if (val & CLK_NO_XTAL) {
+		prev_clock_idx = (val >> CLK_TBG_SEL_SHIFT) & CLK_TBG_SEL_MASK;
+		prev_d1d2 = ((val >> CLK_TBG_DIV1_SHIFT) & CLK_TBG_DIV1_MASK) *
+			    ((val >> CLK_TBG_DIV2_SHIFT) & CLK_TBG_DIV2_MASK);
+	} else {
+		prev_clock_idx = PARENT_CLOCK_XTAL;
+		prev_d1d2 = 1;
+	}
+
+	/* Note that uart_clock_base->parent_rates[i] may not be available */
+	prev_clock_rate = uart_clock_base->parent_rates[prev_clock_idx];
+
+	/* Recalculate UART1 divisor so UART1 baudrate does not change */
+	if (prev_clock_rate) {
+		divisor = DIV_U64_ROUND_CLOSEST((u64)(val & BRDV_BAUD_MASK) *
+						parent_clock_rate * prev_d1d2,
+						prev_clock_rate * d1 * d2);
+		if (divisor < 1)
+			divisor = 1;
+		else if (divisor > BRDV_BAUD_MAX)
+			divisor = BRDV_BAUD_MAX;
+		val = (val & ~BRDV_BAUD_MASK) | divisor;
+	}
+
+	if (parent_clock_idx != PARENT_CLOCK_XTAL) {
+		/* Do not use XTAL, select TBG clock and TBG d1 * d2 divisors */
+		val |= CLK_NO_XTAL;
+		val &= ~(CLK_TBG_DIV1_MASK << CLK_TBG_DIV1_SHIFT);
+		val |= d1 << CLK_TBG_DIV1_SHIFT;
+		val &= ~(CLK_TBG_DIV2_MASK << CLK_TBG_DIV2_SHIFT);
+		val |= d2 << CLK_TBG_DIV2_SHIFT;
+		val &= ~(CLK_TBG_SEL_MASK << CLK_TBG_SEL_SHIFT);
+		val |= parent_clock_idx << CLK_TBG_SEL_SHIFT;
+	} else {
+		/* Use XTAL, TBG bits are then ignored */
+		val &= ~CLK_NO_XTAL;
+	}
+
+	writel(val, uart_clock_base->reg1);
+
+	/* Recalculate UART2 divisor so UART2 baudrate does not change */
+	if (prev_clock_rate) {
+		val = readl(uart_clock_base->reg2);
+		divisor = DIV_U64_ROUND_CLOSEST((u64)(val & BRDV_BAUD_MASK) *
+						parent_clock_rate * prev_d1d2,
+						prev_clock_rate * d1 * d2);
+		if (divisor < 1)
+			divisor = 1;
+		else if (divisor > BRDV_BAUD_MAX)
+			divisor = BRDV_BAUD_MAX;
+		val = (val & ~BRDV_BAUD_MASK) | divisor;
+		writel(val, uart_clock_base->reg2);
+	}
+
+	uart_clock_base->configured = true;
+
+	spin_unlock_irqrestore(&mvebu_uart_lock, flags);
+
+	return 0;
+}
+
+static int mvebu_uart_clock_enable(struct clk_hw *hw)
+{
+	struct mvebu_uart_clock *uart_clock = to_uart_clock(hw);
+	struct mvebu_uart_clock_base *uart_clock_base =
+						to_uart_clock_base(uart_clock);
+	unsigned long flags;
+	u32 val;
+
+	spin_lock_irqsave(&mvebu_uart_lock, flags);
+
+	val = readl(uart_clock_base->reg1);
+
+	if (uart_clock->clock_idx == 0)
+		val &= ~UART1_CLK_DIS;
+	else
+		val &= ~UART2_CLK_DIS;
+
+	writel(val, uart_clock_base->reg1);
+
+	spin_unlock_irqrestore(&mvebu_uart_lock, flags);
+
+	return 0;
+}
+
+static void mvebu_uart_clock_disable(struct clk_hw *hw)
+{
+	struct mvebu_uart_clock *uart_clock = to_uart_clock(hw);
+	struct mvebu_uart_clock_base *uart_clock_base =
+						to_uart_clock_base(uart_clock);
+	unsigned long flags;
+	u32 val;
+
+	spin_lock_irqsave(&mvebu_uart_lock, flags);
+
+	val = readl(uart_clock_base->reg1);
+
+	if (uart_clock->clock_idx == 0)
+		val |= UART1_CLK_DIS;
+	else
+		val |= UART2_CLK_DIS;
+
+	writel(val, uart_clock_base->reg1);
+
+	spin_unlock_irqrestore(&mvebu_uart_lock, flags);
+}
+
+static int mvebu_uart_clock_is_enabled(struct clk_hw *hw)
+{
+	struct mvebu_uart_clock *uart_clock = to_uart_clock(hw);
+	struct mvebu_uart_clock_base *uart_clock_base =
+						to_uart_clock_base(uart_clock);
+	u32 val;
+
+	val = readl(uart_clock_base->reg1);
+
+	if (uart_clock->clock_idx == 0)
+		return !(val & UART1_CLK_DIS);
+	else
+		return !(val & UART2_CLK_DIS);
+}
+
+static int mvebu_uart_clock_save_context(struct clk_hw *hw)
+{
+	struct mvebu_uart_clock *uart_clock = to_uart_clock(hw);
+	struct mvebu_uart_clock_base *uart_clock_base =
+						to_uart_clock_base(uart_clock);
+	unsigned long flags;
+
+	spin_lock_irqsave(&mvebu_uart_lock, flags);
+	uart_clock->pm_context_reg1 = readl(uart_clock_base->reg1);
+	uart_clock->pm_context_reg2 = readl(uart_clock_base->reg2);
+	spin_unlock_irqrestore(&mvebu_uart_lock, flags);
+
+	return 0;
+}
+
+static void mvebu_uart_clock_restore_context(struct clk_hw *hw)
+{
+	struct mvebu_uart_clock *uart_clock = to_uart_clock(hw);
+	struct mvebu_uart_clock_base *uart_clock_base =
+						to_uart_clock_base(uart_clock);
+	unsigned long flags;
+
+	spin_lock_irqsave(&mvebu_uart_lock, flags);
+	writel(uart_clock->pm_context_reg1, uart_clock_base->reg1);
+	writel(uart_clock->pm_context_reg2, uart_clock_base->reg2);
+	spin_unlock_irqrestore(&mvebu_uart_lock, flags);
+}
+
+static unsigned long mvebu_uart_clock_recalc_rate(struct clk_hw *hw,
+						  unsigned long parent_rate)
+{
+	struct mvebu_uart_clock *uart_clock = to_uart_clock(hw);
+	struct mvebu_uart_clock_base *uart_clock_base =
+						to_uart_clock_base(uart_clock);
+
+	return parent_rate / uart_clock_base->div;
+}
+
+static long mvebu_uart_clock_round_rate(struct clk_hw *hw, unsigned long rate,
+					unsigned long *parent_rate)
+{
+	struct mvebu_uart_clock *uart_clock = to_uart_clock(hw);
+	struct mvebu_uart_clock_base *uart_clock_base =
+						to_uart_clock_base(uart_clock);
+
+	return *parent_rate / uart_clock_base->div;
+}
+
+static int mvebu_uart_clock_set_rate(struct clk_hw *hw, unsigned long rate,
+				     unsigned long parent_rate)
+{
+	/*
+	 * We must report success but we can do so unconditionally because
+	 * mvebu_uart_clock_round_rate returns values that ensure this call is a
+	 * nop.
+	 */
+
+	return 0;
+}
+
+static const struct clk_ops mvebu_uart_clock_ops = {
+	.prepare = mvebu_uart_clock_prepare,
+	.enable = mvebu_uart_clock_enable,
+	.disable = mvebu_uart_clock_disable,
+	.is_enabled = mvebu_uart_clock_is_enabled,
+	.save_context = mvebu_uart_clock_save_context,
+	.restore_context = mvebu_uart_clock_restore_context,
+	.round_rate = mvebu_uart_clock_round_rate,
+	.set_rate = mvebu_uart_clock_set_rate,
+	.recalc_rate = mvebu_uart_clock_recalc_rate,
+};
+
+static int mvebu_uart_clock_register(struct device *dev,
+				     struct mvebu_uart_clock *uart_clock,
+				     const char *name,
+				     const char *parent_name)
+{
+	struct clk_init_data init = { };
+
+	uart_clock->clk_hw.init = &init;
+
+	init.name = name;
+	init.ops = &mvebu_uart_clock_ops;
+	init.flags = 0;
+	init.num_parents = 1;
+	init.parent_names = &parent_name;
+
+	return devm_clk_hw_register(dev, &uart_clock->clk_hw);
+}
+
+static int mvebu_uart_clock_probe(struct platform_device *pdev)
+{
+	static const char *const uart_clk_names[] = { "uart_1", "uart_2" };
+	static const char *const parent_clk_names[] = { "TBG-A-P", "TBG-B-P",
+							"TBG-A-S", "TBG-B-S",
+							"xtal" };
+	struct clk *parent_clks[ARRAY_SIZE(parent_clk_names)];
+	struct mvebu_uart_clock_base *uart_clock_base;
+	struct clk_hw_onecell_data *hw_clk_data;
+	struct device *dev = &pdev->dev;
+	int i, parent_clk_idx, ret;
+	unsigned long div, rate;
+	struct resource *res;
+	unsigned int d1, d2;
+
+	BUILD_BUG_ON(ARRAY_SIZE(uart_clk_names) !=
+		     ARRAY_SIZE(uart_clock_base->clocks));
+	BUILD_BUG_ON(ARRAY_SIZE(parent_clk_names) !=
+		     ARRAY_SIZE(uart_clock_base->parent_rates));
+
+	uart_clock_base = devm_kzalloc(dev,
+				       sizeof(*uart_clock_base),
+				       GFP_KERNEL);
+	if (!uart_clock_base)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(dev, "Couldn't get first register\n");
+		return -ENOENT;
+	}
+
+	/*
+	 * UART Clock Control register (reg1 / UART_BRDV) is in the address
+	 * space of UART1 (standard UART variant), controls parent clock and
+	 * dividers for both UART1 and UART2 and is supplied via DT as the first
+	 * resource. Therefore use ioremap() rather than ioremap_resource() to
+	 * avoid conflicts with UART1 driver. Access to UART_BRDV is protected
+	 * by a lock shared between clock and UART driver.
+	 */
+	uart_clock_base->reg1 = devm_ioremap(dev, res->start,
+					     resource_size(res));
+	if (!uart_clock_base->reg1)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (!res) {
+		dev_err(dev, "Couldn't get second register\n");
+		return -ENOENT;
+	}
+
+	/*
+	 * UART 2 Baud Rate Divisor register (reg2 / UART_BRDV) is in address
+	 * space of UART2 (extended UART variant), controls only one UART2
+	 * specific divider and is supplied via DT as second resource.
+	 * Therefore use ioremap() rather than ioremap_resource() to avoid
+	 * conflicts with UART2 driver. Access to UART_BRDV is protected by a
+	 * by lock shared between clock and UART driver.
+	 */
+	uart_clock_base->reg2 = devm_ioremap(dev, res->start,
+					     resource_size(res));
+	if (!uart_clock_base->reg2)
+		return -ENOMEM;
+
+	hw_clk_data = devm_kzalloc(dev,
+				   struct_size(hw_clk_data, hws,
+					       ARRAY_SIZE(uart_clk_names)),
+				   GFP_KERNEL);
+	if (!hw_clk_data)
+		return -ENOMEM;
+
+	hw_clk_data->num = ARRAY_SIZE(uart_clk_names);
+	for (i = 0; i < ARRAY_SIZE(uart_clk_names); i++) {
+		hw_clk_data->hws[i] = &uart_clock_base->clocks[i].clk_hw;
+		uart_clock_base->clocks[i].clock_idx = i;
+	}
+
+	parent_clk_idx = -1;
+
+	for (i = 0; i < ARRAY_SIZE(parent_clk_names); i++) {
+		parent_clks[i] = devm_clk_get(dev, parent_clk_names[i]);
+		if (IS_ERR(parent_clks[i])) {
+			if (PTR_ERR(parent_clks[i]) == -EPROBE_DEFER)
+				return -EPROBE_DEFER;
+			dev_warn(dev, "Couldn't get the parent clock %s: %ld\n",
+				 parent_clk_names[i], PTR_ERR(parent_clks[i]));
+			continue;
+		}
+
+		ret = clk_prepare_enable(parent_clks[i]);
+		if (ret) {
+			dev_warn(dev, "Couldn't enable parent clock %s: %d\n",
+				 parent_clk_names[i], ret);
+			continue;
+		}
+		rate = clk_get_rate(parent_clks[i]);
+		uart_clock_base->parent_rates[i] = rate;
+
+		if (i != PARENT_CLOCK_XTAL) {
+			/*
+			 * Calculate the smallest TBG d1 and d2 divisors that
+			 * still can provide 9600 baudrate.
+			 */
+			d1 = DIV_ROUND_UP(rate, 9600 * OSAMP_MAX_DIVISOR *
+					  BRDV_BAUD_MAX);
+			if (d1 < 1)
+				d1 = 1;
+			else if (d1 > CLK_TBG_DIV1_MAX)
+				d1 = CLK_TBG_DIV1_MAX;
+
+			d2 = DIV_ROUND_UP(rate, 9600 * OSAMP_MAX_DIVISOR *
+					  BRDV_BAUD_MAX * d1);
+			if (d2 < 1)
+				d2 = 1;
+			else if (d2 > CLK_TBG_DIV2_MAX)
+				d2 = CLK_TBG_DIV2_MAX;
+		} else {
+			/*
+			 * When UART clock uses XTAL clock as a source then it
+			 * is not possible to use d1 and d2 divisors.
+			 */
+			d1 = d2 = 1;
+		}
+
+		/* Skip clock source which cannot provide 9600 baudrate */
+		if (rate > 9600 * OSAMP_MAX_DIVISOR * BRDV_BAUD_MAX * d1 * d2)
+			continue;
+
+		/*
+		 * Choose TBG clock source with the smallest divisors. Use XTAL
+		 * clock source only in case TBG is not available as XTAL cannot
+		 * be used for baudrates higher than 230400.
+		 */
+		if (parent_clk_idx == -1 ||
+		    (i != PARENT_CLOCK_XTAL && div > d1 * d2)) {
+			parent_clk_idx = i;
+			div = d1 * d2;
+		}
+	}
+
+	for (i = 0; i < ARRAY_SIZE(parent_clk_names); i++) {
+		if (i == parent_clk_idx || IS_ERR(parent_clks[i]))
+			continue;
+		clk_disable_unprepare(parent_clks[i]);
+		devm_clk_put(dev, parent_clks[i]);
+	}
+
+	if (parent_clk_idx == -1) {
+		dev_err(dev, "No usable parent clock\n");
+		return -ENOENT;
+	}
+
+	uart_clock_base->parent_idx = parent_clk_idx;
+	uart_clock_base->div = div;
+
+	dev_notice(dev, "Using parent clock %s as base UART clock\n",
+		   __clk_get_name(parent_clks[parent_clk_idx]));
+
+	for (i = 0; i < ARRAY_SIZE(uart_clk_names); i++) {
+		ret = mvebu_uart_clock_register(dev,
+				&uart_clock_base->clocks[i],
+				uart_clk_names[i],
+				__clk_get_name(parent_clks[parent_clk_idx]));
+		if (ret) {
+			dev_err(dev, "Can't register UART clock %d: %d\n",
+				i, ret);
+			return ret;
+		}
+	}
+
+	return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
+					   hw_clk_data);
+}
+
+static const struct of_device_id mvebu_uart_clock_of_match[] = {
+	{ .compatible = "marvell,armada-3700-uart-clock", },
+	{ }
+};
+
+static struct platform_driver mvebu_uart_clock_platform_driver = {
+	.probe = mvebu_uart_clock_probe,
+	.driver		= {
+		.name	= "mvebu-uart-clock",
+		.of_match_table = mvebu_uart_clock_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_clock_platform_driver);
+	if (ret) {
+		uart_unregister_driver(&mvebu_uart_driver);
+		return ret;
+	}
+
+	ret = platform_driver_register(&mvebu_uart_platform_driver);
+	if (ret) {
+		platform_driver_unregister(&mvebu_uart_clock_platform_driver);
+		uart_unregister_driver(&mvebu_uart_driver);
+		return ret;
+	}
+
+	return 0;
+}
+arch_initcall(mvebu_uart_init);