1 files changed, 803 insertions, 0 deletions

diff --git a/drivers/serial/mxs-duart.c b/drivers/serial/mxs-duart.c
new file mode 100644
index 000000000000..64e5057344e1
--- /dev/null
+++ b/drivers/serial/mxs-duart.c
@@ -0,0 +1,803 @@
+/*
+ * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
+ * Copyright (C) 2009-2010 Freescale Semiconductor, Inc.
+ *
+ * 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.
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#if defined(CONFIG_SERIAL_MXS_DUART_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
+#include <linux/module.h>
+#include <linux/ioport.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/sysrq.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/serial_core.h>
+#include <linux/serial.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+
+#include <mach/hardware.h>
+#include <mach/device.h>
+#include "regs-duart.h"
+
+/* treated as variable unless submitted to open-source */
+#define PORT_DUART		100
+#define SERIAL_DUART_MAJOR	204
+#define SERIAL_DUART_MINOR	16
+#define SERIAL_RX_LIMIT		256
+#define ISR_PASS_LIMIT		256
+
+#define DUART_DEVID		"DebugUART"
+
+static int force_cd = 1;
+static struct uart_driver duart_drv;
+
+/*
+ * We wrap our port structure around the generic uart_port.
+ */
+struct duart_port {
+	struct uart_port port;
+	struct clk *clk;
+	unsigned int im;	/* interrupt mask */
+	unsigned int old_status;
+	int suspended;
+};
+
+static void duart_stop_tx(struct uart_port *port)
+{
+	struct duart_port *dp = container_of(port, struct duart_port, port);
+
+	dp->im &= ~BM_UARTDBGIMSC_TXIM;
+	__raw_writel(dp->im, dp->port.membase + HW_UARTDBGIMSC);
+}
+
+static void duart_start_tx(struct uart_port *port)
+{
+	struct duart_port *dp = container_of(port, struct duart_port, port);
+
+	dp->im |= BM_UARTDBGIMSC_TXIM;
+	__raw_writel(dp->im, dp->port.membase + HW_UARTDBGIMSC);
+}
+
+static void duart_stop_rx(struct uart_port *port)
+{
+	struct duart_port *dp = container_of(port, struct duart_port, port);
+
+	dp->im &= ~(BM_UARTDBGIMSC_OEIM | BM_UARTDBGIMSC_BEIM |
+		    BM_UARTDBGIMSC_PEIM | BM_UARTDBGIMSC_FEIM |
+		    BM_UARTDBGIMSC_RTIM | BM_UARTDBGIMSC_RXIM);
+	__raw_writel(dp->im, dp->port.membase + HW_UARTDBGIMSC);
+}
+
+static void duart_enable_ms(struct uart_port *port)
+{
+	struct duart_port *dp = container_of(port, struct duart_port, port);
+
+	dp->im |= BM_UARTDBGIMSC_RIMIM | BM_UARTDBGIMSC_CTSMIM |
+	    BM_UARTDBGIMSC_DCDMIM | BM_UARTDBGIMSC_DSRMIM;
+	__raw_writel(dp->im, dp->port.membase + HW_UARTDBGIMSC);
+}
+
+static void duart_rx_chars(struct duart_port *dp)
+{
+	struct tty_struct *tty = dp->port.state->port.tty;
+	unsigned int status, ch, flag, rsr, max_count = SERIAL_RX_LIMIT;
+
+	status = __raw_readl(dp->port.membase + HW_UARTDBGFR);
+	while ((status & BM_UARTDBGFR_RXFE) == 0 && max_count--) {
+		ch = __raw_readl(dp->port.membase + HW_UARTDBGDR);
+		flag = TTY_NORMAL;
+		dp->port.icount.rx++;
+
+		/*
+		 * Note that the error handling code is
+		 * out of the main execution path
+		 */
+		rsr = __raw_readl(dp->port.membase + HW_UARTDBGRSR_ECR);
+		if (unlikely(rsr & (BM_UARTDBGRSR_ECR_OE |
+				    BM_UARTDBGRSR_ECR_BE |
+				    BM_UARTDBGRSR_ECR_PE |
+				    BM_UARTDBGRSR_ECR_FE))) {
+			if (rsr & BM_UARTDBGRSR_ECR_BE) {
+				rsr &= ~(BM_UARTDBGRSR_ECR_FE |
+					 BM_UARTDBGRSR_ECR_PE);
+				dp->port.icount.brk++;
+				if (uart_handle_break(&dp->port))
+					goto ignore_char;
+			} else if (rsr & BM_UARTDBGRSR_ECR_PE)
+				dp->port.icount.parity++;
+			else if (rsr & BM_UARTDBGRSR_ECR_FE)
+				dp->port.icount.frame++;
+			if (rsr & BM_UARTDBGRSR_ECR_OE)
+				dp->port.icount.overrun++;
+
+			rsr &= dp->port.read_status_mask;
+
+			if (rsr & BM_UARTDBGRSR_ECR_BE)
+				flag = TTY_BREAK;
+			else if (rsr & BM_UARTDBGRSR_ECR_PE)
+				flag = TTY_PARITY;
+			else if (rsr & BM_UARTDBGRSR_ECR_FE)
+				flag = TTY_FRAME;
+		}
+
+		if (uart_handle_sysrq_char(&dp->port, ch))
+			goto ignore_char;
+
+		uart_insert_char(&dp->port, rsr, BM_UARTDBGRSR_ECR_OE, ch,
+				 flag);
+
+ignore_char:
+		status = __raw_readl(dp->port.membase + HW_UARTDBGFR);
+	}
+	tty_flip_buffer_push(tty);
+	return;
+}
+
+static void duart_tx_chars(struct duart_port *dp)
+{
+	int count;
+	struct circ_buf *xmit = &dp->port.state->xmit;
+
+	if (dp->port.x_char) {
+		__raw_writel(dp->port.x_char, dp->port.membase + HW_UARTDBGDR);
+		dp->port.icount.tx++;
+		dp->port.x_char = 0;
+		return;
+	}
+	if (uart_circ_empty(xmit) || uart_tx_stopped(&dp->port)) {
+		duart_stop_tx(&dp->port);
+		return;
+	}
+
+	count = dp->port.fifosize >> 1;
+	do {
+		__raw_writel(xmit->buf[xmit->tail],
+			     dp->port.membase + HW_UARTDBGDR);
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		dp->port.icount.tx++;
+		if (uart_circ_empty(xmit))
+			break;
+	} while (--count > 0);
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(&dp->port);
+
+	if (uart_circ_empty(xmit))
+		duart_stop_tx(&dp->port);
+}
+
+static void duart_modem_status(struct duart_port *dp)
+{
+	unsigned int status, delta;
+	status = __raw_readl(dp->port.membase + HW_UARTDBGFR) &
+	    (BM_UARTDBGFR_DCD | BM_UARTDBGFR_DSR | BM_UARTDBGFR_CTS);
+
+	delta = status ^ dp->old_status;
+	dp->old_status = status;
+
+	if (!delta)
+		return;
+
+	if (delta & BM_UARTDBGFR_DCD)
+		uart_handle_dcd_change(&dp->port, status & BM_UARTDBGFR_DCD);
+
+	if (delta & BM_UARTDBGFR_DSR)
+		dp->port.icount.dsr++;
+
+	if (delta & BM_UARTDBGFR_CTS)
+		uart_handle_cts_change(&dp->port, status & BM_UARTDBGFR_CTS);
+
+	wake_up_interruptible(&dp->port.state->port.delta_msr_wait);
+}
+
+static irqreturn_t duart_int(int irq, void *dev_id)
+{
+	int handled = 0;
+	struct duart_port *dp = dev_id;
+	unsigned int status, pass_counter = ISR_PASS_LIMIT;
+
+	spin_lock(&dp->port.lock);
+
+	status = __raw_readl(dp->port.membase + HW_UARTDBGMIS);
+	while (status) {
+		handled = 1;
+
+		__raw_writel(status & ~(BM_UARTDBGMIS_TXMIS |
+					BM_UARTDBGMIS_RTMIS |
+					BM_UARTDBGMIS_RXMIS),
+			     dp->port.membase + HW_UARTDBGICR);
+
+		if (status & (BM_UARTDBGMIS_RTMIS | BM_UARTDBGMIS_RXMIS))
+			duart_rx_chars(dp);
+		if (status & (BM_UARTDBGMIS_DSRMMIS |
+			      BM_UARTDBGMIS_DCDMMIS |
+			      BM_UARTDBGMIS_CTSMMIS | BM_UARTDBGMIS_RIMMIS))
+			duart_modem_status(dp);
+		if (status & BM_UARTDBGMIS_TXMIS)
+			duart_tx_chars(dp);
+
+		if (pass_counter-- == 0)
+			break;
+
+		status = __raw_readl(dp->port.membase + HW_UARTDBGMIS);
+	};
+
+	spin_unlock(&dp->port.lock);
+
+	return IRQ_RETVAL(handled);
+}
+
+static unsigned int duart_tx_empty(struct uart_port *port)
+{
+	struct duart_port *dp = (struct duart_port *)port;
+	unsigned int status = __raw_readl(dp->port.membase + HW_UARTDBGFR);
+	return status & (BM_UARTDBGFR_BUSY | BM_UARTDBGFR_TXFF) ?
+	    0 : TIOCSER_TEMT;
+}
+
+static unsigned int duart_get_mctrl(struct uart_port *port)
+{
+	unsigned int result = 0;
+	struct duart_port *dp = (struct duart_port *)port;
+	unsigned int status = __raw_readl(dp->port.membase + HW_UARTDBGFR);
+
+#define TEST_AND_SET_BIT(uartbit, tiocmbit)	do { \
+		if (status & uartbit)		\
+			result |= tiocmbit;	\
+	} while (0)
+
+	TEST_AND_SET_BIT(BM_UARTDBGFR_DCD, TIOCM_CAR);
+	TEST_AND_SET_BIT(BM_UARTDBGFR_DSR, TIOCM_DSR);
+	TEST_AND_SET_BIT(BM_UARTDBGFR_CTS, TIOCM_CTS);
+	TEST_AND_SET_BIT(BM_UARTDBGFR_RI, TIOCM_RNG);
+#undef TEST_AND_SET_BIT
+	if (force_cd)
+		result |= TIOCM_CAR;
+	return result;
+}
+
+static void duart_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	unsigned int cr;
+	struct duart_port *dp = (struct duart_port *)port;
+
+	cr = __raw_readl(dp->port.membase + HW_UARTDBGCR);
+
+#define	TEST_AND_SET_BIT(tiocmbit, uartbit)	do { \
+		if (mctrl & tiocmbit)		\
+			cr |= uartbit;		\
+		else				\
+			cr &= ~uartbit;		\
+	} while (0)
+
+	TEST_AND_SET_BIT(TIOCM_RTS, BM_UARTDBGCR_RTS);
+	TEST_AND_SET_BIT(TIOCM_DTR, BM_UARTDBGCR_DTR);
+	TEST_AND_SET_BIT(TIOCM_OUT1, BM_UARTDBGCR_OUT1);
+	TEST_AND_SET_BIT(TIOCM_OUT2, BM_UARTDBGCR_OUT2);
+	TEST_AND_SET_BIT(TIOCM_LOOP, BM_UARTDBGCR_LBE);
+#undef TEST_AND_SET_BIT
+
+	__raw_writel(cr, dp->port.membase + HW_UARTDBGCR);
+}
+
+static void duart_break_ctl(struct uart_port *port, int break_state)
+{
+	unsigned long flags;
+	unsigned int lcr_h;
+	struct duart_port *dp = (struct duart_port *)port;
+
+	spin_lock_irqsave(&dp->port.lock, flags);
+	lcr_h = __raw_readl(dp->port.membase + HW_UARTDBGLCR_H);
+	if (break_state == -1)
+		lcr_h |= BM_UARTDBGLCR_H_BRK;
+	else
+		lcr_h &= ~BM_UARTDBGLCR_H_BRK;
+	__raw_writel(lcr_h, dp->port.membase + HW_UARTDBGLCR_H);
+	spin_unlock_irqrestore(&dp->port.lock, flags);
+}
+
+static int duart_startup(struct uart_port *port)
+{
+	u32 cr, lcr;
+	int retval;
+	struct duart_port *dp = (struct duart_port *)port;
+
+	/*
+	 * Allocate the IRQ
+	 */
+	retval = request_irq(dp->port.irq, duart_int, 0, DUART_DEVID, dp);
+	if (retval)
+		return retval;
+
+	/* wake up the UART */
+	__raw_writel(0, dp->port.membase + HW_UARTDBGDR);
+
+	__raw_writel(BF_UARTDBGIFLS_TXIFLSEL(BV_UARTDBGIFLS_TXIFLSEL__ONE_HALF)
+		     |
+		     BF_UARTDBGIFLS_RXIFLSEL(BV_UARTDBGIFLS_RXIFLSEL__ONE_HALF),
+		     dp->port.membase + HW_UARTDBGIFLS);
+
+	/*
+	 * Provoke TX FIFO interrupt into asserting.
+	 */
+	cr = BM_UARTDBGCR_UARTEN | BM_UARTDBGCR_RXE | BM_UARTDBGCR_TXE;
+	__raw_writel(cr, dp->port.membase + HW_UARTDBGCR);
+
+	lcr = __raw_readl(dp->port.membase + HW_UARTDBGLCR_H);
+	lcr |= BM_UARTDBGLCR_H_FEN;
+	__raw_writel(lcr, dp->port.membase + HW_UARTDBGLCR_H);
+
+	/*
+	 * initialise the old status of the modem signals
+	 */
+	dp->old_status = __raw_readl(dp->port.membase + HW_UARTDBGFR) &
+	    (BM_UARTDBGFR_DCD | BM_UARTDBGFR_DSR | BM_UARTDBGFR_CTS);
+	/*
+	 * Finally, enable interrupts
+	 */
+	dp->im = BM_UARTDBGIMSC_RXIM | BM_UARTDBGIMSC_RTIM;
+	__raw_writel(dp->im, dp->port.membase + HW_UARTDBGIMSC);
+
+	return 0;
+}
+
+static void duart_shutdown(struct uart_port *port)
+{
+	unsigned long flags;
+	unsigned int val;
+	struct duart_port *dp = (struct duart_port *)port;
+
+	/*
+	 * disable all interrupts
+	 */
+	spin_lock_irqsave(&dp->port.lock, flags);
+	dp->im = 0;
+	__raw_writel(dp->im, dp->port.membase + HW_UARTDBGIMSC);
+	__raw_writel(0xffff, dp->port.membase + HW_UARTDBGICR);
+	spin_unlock_irqrestore(&dp->port.lock, flags);
+
+	free_irq(dp->port.irq, dp);
+
+	/*
+	 * disable the port
+	 */
+	__raw_writel(BM_UARTDBGCR_UARTEN | BM_UARTDBGCR_TXE,
+		     dp->port.membase + HW_UARTDBGCR);
+	/*
+	 * disable break condition and fifos
+	 */
+	val = __raw_readl(dp->port.membase + HW_UARTDBGLCR_H);
+	val &= ~(BM_UARTDBGLCR_H_BRK | BM_UARTDBGLCR_H_FEN);
+	__raw_writel(val, dp->port.membase + HW_UARTDBGLCR_H);
+}
+
+static void
+duart_set_termios(struct uart_port *port, struct ktermios *termios,
+		  struct ktermios *old)
+{
+	unsigned int lcr_h, old_cr;
+	unsigned long flags;
+	unsigned int baud, quot;
+
+	/*
+	 * Ask the core to calculate the divisor for us.
+	 */
+	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
+	quot = (port->uartclk << 2) / baud;
+
+	switch (termios->c_cflag & CSIZE) {
+	case CS5:
+		lcr_h = BF_UARTDBGLCR_H_WLEN(0);
+		break;
+	case CS6:
+		lcr_h = BF_UARTDBGLCR_H_WLEN(1);
+		break;
+	case CS7:
+		lcr_h = BF_UARTDBGLCR_H_WLEN(2);
+		break;
+	default:		/* CS8 */
+		lcr_h = BF_UARTDBGLCR_H_WLEN(3);
+		break;
+	}
+	if (termios->c_cflag & CSTOPB)
+		lcr_h |= BM_UARTDBGLCR_H_STP2;
+	if (termios->c_cflag & PARENB) {
+		lcr_h |= BM_UARTDBGLCR_H_PEN;
+		if (!(termios->c_cflag & PARODD))
+			lcr_h |= BM_UARTDBGLCR_H_EPS;
+	}
+	lcr_h |= BM_UARTDBGLCR_H_FEN;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	/*
+	 * Update the per-port timeout.
+	 */
+	uart_update_timeout(port, termios->c_cflag, baud);
+
+	port->read_status_mask = BM_UARTDBGRSR_ECR_OE;
+	if (termios->c_iflag & INPCK)
+		port->read_status_mask |= BM_UARTDBGRSR_ECR_FE |
+		    BM_UARTDBGRSR_ECR_PE;
+	if (termios->c_iflag & (BRKINT | PARMRK))
+		port->read_status_mask |= BM_UARTDBGRSR_ECR_BE;
+
+	/*
+	 * Characters to ignore
+	 */
+	port->ignore_status_mask = 0;
+	if (termios->c_iflag & IGNPAR)
+		port->ignore_status_mask |= BM_UARTDBGRSR_ECR_FE |
+		    BM_UARTDBGRSR_ECR_PE;
+	if (termios->c_iflag & IGNBRK) {
+		port->ignore_status_mask |= BM_UARTDBGRSR_ECR_BE;
+		/*
+		 * If we're ignoring parity and break indicators,
+		 * ignore overruns too (for real raw support).
+		 */
+		if (termios->c_iflag & IGNPAR)
+			port->ignore_status_mask |= BM_UARTDBGRSR_ECR_OE;
+	}
+
+	if (UART_ENABLE_MS(port, termios->c_cflag))
+		duart_enable_ms(port);
+
+	/* first, disable everything */
+	old_cr = __raw_readl(port->membase + HW_UARTDBGCR);
+	__raw_writel(0, port->membase + HW_UARTDBGCR);
+
+	/* Set baud rate */
+	__raw_writel(quot & 0x3f, port->membase + HW_UARTDBGFBRD);
+	__raw_writel(quot >> 6, port->membase + HW_UARTDBGIBRD);
+	/*
+	 * ----------v----------v----------v----------v-----
+	 * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
+	 * ----------^----------^----------^----------^-----
+	 */
+	__raw_writel(lcr_h, port->membase + HW_UARTDBGLCR_H);
+	__raw_writel(old_cr, port->membase + HW_UARTDBGCR);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *duart_type(struct uart_port *port)
+{
+	return port->type == PORT_DUART ? DUART_DEVID : NULL;
+}
+
+/*
+ * Release the memory region(s) being used by 'port'
+ */
+static void duart_release_port(struct uart_port *port)
+{
+	release_mem_region(port->mapbase, PAGE_SIZE);
+}
+
+/*
+ * Request the memory region(s) being used by 'port'
+ */
+static int duart_request_port(struct uart_port *port)
+{
+	return request_mem_region(port->mapbase, PAGE_SIZE, DUART_DEVID)
+	    != NULL ? 0 : -EBUSY;
+}
+
+/*
+ * Configure/autoconfigure the port.
+ */
+static void duart_config_port(struct uart_port *port, int flags)
+{
+	if (flags & UART_CONFIG_TYPE) {
+		port->type = PORT_DUART;
+		duart_request_port(port);
+	}
+}
+
+/*
+ * verify the new serial_struct (for TIOCSSERIAL).
+ */
+static int duart_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+	int ret = 0;
+	if (ser->type != PORT_UNKNOWN && ser->type != PORT_DUART)
+		ret = -EINVAL;
+	if (ser->irq < 0 || ser->irq >= NR_IRQS)
+		ret = -EINVAL;
+	if (ser->baud_base < 9600)
+		ret = -EINVAL;
+	return ret;
+}
+
+static struct uart_ops duart_pops = {
+	.tx_empty = duart_tx_empty,
+	.set_mctrl = duart_set_mctrl,
+	.get_mctrl = duart_get_mctrl,
+	.stop_tx = duart_stop_tx,
+	.start_tx = duart_start_tx,
+	.stop_rx = duart_stop_rx,
+	.enable_ms = duart_enable_ms,
+	.break_ctl = duart_break_ctl,
+	.startup = duart_startup,
+	.shutdown = duart_shutdown,
+	.set_termios = duart_set_termios,
+	.type = duart_type,
+	.release_port = duart_release_port,
+	.request_port = duart_request_port,
+	.config_port = duart_config_port,
+	.verify_port = duart_verify_port,
+};
+
+static struct duart_port duart_port = {
+	.port = {
+		 .iotype = SERIAL_IO_MEM,
+#ifdef CONFIG_MXS_EARLY_CONSOLE
+		 .membase = MXS_DEBUG_CONSOLE_VIRT,
+		 .mapbase = MXS_DEBUG_CONSOLE_PHYS,
+#endif
+		 .fifosize = 16,
+		 .ops = &duart_pops,
+		 .flags = ASYNC_BOOT_AUTOCONF,
+		 .line = 0,
+		 },
+};
+
+#ifdef CONFIG_SERIAL_MXS_DUART_CONSOLE
+
+static void
+duart_console_write(struct console *co, const char *s, unsigned int count)
+{
+	struct uart_port *port = &duart_port.port;
+	unsigned int status, old_cr;
+	int i;
+	/*
+	 *      First save the CR then disable the interrupts
+	 */
+	old_cr = __raw_readl(port->membase + HW_UARTDBGCR);
+	__raw_writel(BM_UARTDBGCR_UARTEN | BM_UARTDBGCR_TXE,
+		     port->membase + HW_UARTDBGCR);
+	/*
+	 *      Now, do each character
+	 */
+	for (i = 0; i < count; i++) {
+		do {
+			status = __raw_readl(port->membase + HW_UARTDBGFR);
+		} while (status & BM_UARTDBGFR_TXFF);
+
+		__raw_writel(s[i], port->membase + HW_UARTDBGDR);
+		if (s[i] == '\n') {
+			do {
+				status = __raw_readl(port->membase +
+						     HW_UARTDBGFR);
+			} while (status & BM_UARTDBGFR_TXFF);
+			__raw_writel('\r', port->membase + HW_UARTDBGDR);
+		}
+	}
+
+	/*
+	 *      Finally, wait for transmitter to become empty
+	 *      and restore the TCR
+	 */
+	do {
+		status = __raw_readl(port->membase + HW_UARTDBGFR);
+	} while (status & BM_UARTDBGFR_BUSY);
+	__raw_writel(old_cr, port->membase + HW_UARTDBGCR);
+}
+
+static void __init
+duart_console_get_options(struct uart_port *port, int *baud,
+			  int *parity, int *bits)
+{
+	if (__raw_readl(port->membase + HW_UARTDBGCR) & BM_UARTDBGCR_UARTEN) {
+		unsigned int lcr_h, quot;
+		lcr_h = __raw_readl(port->membase + HW_UARTDBGLCR_H);
+
+		*parity = 'n';
+		if (lcr_h & BM_UARTDBGLCR_H_PEN) {
+			if (lcr_h & BM_UARTDBGLCR_H_EPS)
+				*parity = 'e';
+			else
+				*parity = 'o';
+		}
+
+		if ((lcr_h & BM_UARTDBGLCR_H_WLEN) == BF_UARTDBGLCR_H_WLEN(2))
+			*bits = 7;
+		else
+			*bits = 8;
+
+		quot = (__raw_readl(port->membase + HW_UARTDBGFBRD) & 0x3F) |
+		    __raw_readl(port->membase + HW_UARTDBGIBRD) << 6;
+		if (quot == 0)
+			quot = 1;
+		*baud = (port->uartclk << 2) / quot;
+	}
+}
+
+static int __init duart_console_setup(struct console *co, char *options)
+{
+	struct uart_port *port;
+	int baud = 115200;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+	/*
+	 * Check whether an invalid uart number has been specified, and
+	 * if so, search for the first available port that does have
+	 * console support.
+	 */
+	if (co->index)
+		return -EINVAL;
+
+	port = &duart_port.port;
+
+	if (duart_port.clk == NULL || IS_ERR(duart_port.clk)) {
+		duart_port.clk = clk_get(NULL, "uart");
+		if (duart_port.clk == NULL || IS_ERR(duart_port.clk))
+			return -ENODEV;
+		duart_port.port.uartclk = clk_get_rate(duart_port.clk);
+	}
+
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+	else
+		duart_console_get_options(port, &baud, &parity, &bits);
+	return uart_set_options(port, co, baud, parity, bits, flow);
+}
+
+static struct console duart_console = {
+	.name = "ttyAM",
+	.write = duart_console_write,
+	.device = uart_console_device,
+	.setup = duart_console_setup,
+	.flags = CON_PRINTBUFFER,
+	.index = -1,
+	.data = &duart_drv,
+};
+
+#ifdef CONFIG_MXS_EARLY_CONSOLE
+static int __init duart_console_init(void)
+{
+	register_console(&duart_console);
+	return 0;
+}
+
+console_initcall(duart_console_init);
+#endif
+
+#endif
+
+static struct uart_driver duart_drv = {
+	.owner = THIS_MODULE,
+	.driver_name = "ttyAM",
+	.dev_name = "ttyAM",
+	.major = SERIAL_DUART_MAJOR,
+	.minor = SERIAL_DUART_MINOR,
+	.nr = 1,
+#ifdef CONFIG_SERIAL_MXS_DUART_CONSOLE
+	.cons = &duart_console,
+#endif
+};
+
+static int __devinit duart_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENOMEM;
+	/*
+	 * Will use mapbase and membase here if !CONFIG_MXS_EARLY_CONSOLE,
+	 * or use the overridden values later if CONFIG_MXS_EARLY_CONSOLE
+	 */
+	duart_port.port.mapbase = res->start;
+	duart_port.port.membase =
+	    (unsigned char __iomem *)IO_ADDRESS(res->start);
+
+	duart_port.port.irq = platform_get_irq(pdev, 0);
+	if (duart_port.port.irq < 0)
+		return -EINVAL;
+	device_init_wakeup(&pdev->dev, 1);
+
+	duart_port.clk = clk_get(NULL, "uart");
+	if (duart_port.clk == NULL || IS_ERR(duart_port.clk))
+		return -ENODEV;
+	duart_port.suspended = 0;
+	duart_port.port.dev = &pdev->dev;
+	duart_port.port.uartclk = clk_get_rate(duart_port.clk);
+	uart_add_one_port(&duart_drv, &duart_port.port);
+	return 0;
+}
+
+static int __devexit duart_remove(struct platform_device *pdev)
+{
+	clk_put(duart_port.clk);
+	uart_remove_one_port(&duart_drv, &duart_port.port);
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int duart_suspend(struct platform_device *pdev,
+		pm_message_t state)
+{
+	int ret = 0;
+	if (!duart_port.suspended) {
+		ret = uart_suspend_port(&duart_drv, &duart_port.port);
+		if (!ret)
+			duart_port.suspended = 1;
+	}
+	return ret;
+}
+
+static int duart_resume(struct platform_device *pdev,
+		pm_message_t state)
+{
+	int ret = 0;
+	if (duart_port.suspended) {
+		ret = uart_resume_port(&duart_drv, &duart_port.port);
+		if (!ret)
+			duart_port.suspended = 0;
+	}
+	return ret;
+}
+#else
+#define	duart_suspend	NULL
+#define	duart_resume	NULL
+#endif
+
+static struct platform_driver duart_driver = {
+	.probe = duart_probe,
+	.remove = __devexit_p(duart_remove),
+	.suspend = duart_suspend,
+	.resume = duart_resume,
+	.driver = {
+		   .name = "mxs-duart",
+		   .owner = THIS_MODULE,
+		   },
+};
+
+static int __init duart_init(void)
+{
+	int ret;
+	ret = uart_register_driver(&duart_drv);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&duart_driver);
+	if (ret)
+		uart_unregister_driver(&duart_drv);
+
+	return ret;
+}
+
+static void __exit duart_exit(void)
+{
+	platform_driver_unregister(&duart_driver);
+	uart_unregister_driver(&duart_drv);
+}
+
+module_init(duart_init);
+module_exit(duart_exit);
+module_param(force_cd, int, 0644);
+MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd/Freescale Inc");
+MODULE_DESCRIPTION("i.MXS debug uart");
+MODULE_LICENSE("GPL");