ar71xx: cleanup AR933X UART driver

SVN-Revision: 27222

2 files changed, 152 insertions, 483 deletions

diff --git a/target/linux/ar71xx/files/arch/mips/include/asm/mach-ar71xx/ar933x_uart.h b/target/linux/ar71xx/files/arch/mips/include/asm/mach-ar71xx/ar933x_uart.h
index edb13cd..5273055 100644
--- a/target/linux/ar71xx/files/arch/mips/include/asm/mach-ar71xx/ar933x_uart.h
+++ b/target/linux/ar71xx/files/arch/mips/include/asm/mach-ar71xx/ar933x_uart.h
@@ -11,6 +11,9 @@
 #ifndef __AR933X_UART_H
 #define __AR933X_UART_H
 
+#define AR933X_UART_REGS_SIZE		20
+#define AR933X_UART_FIFO_SIZE		16
+
 #define AR933X_UART_DATA_REG		0x00
 #define AR933X_UART_CS_REG		0x04
 #define AR933X_UART_CLOCK_REG		0x08
@@ -23,9 +26,14 @@
 
 #define AR933X_UART_CS_PARITY_S		0
 #define AR933X_UART_CS_PARITY_M		0x3
-#define AR933X_UART_CS_PARITY_M		0x3
+#define   AR933X_UART_CS_PARITY_NONE	0
+#define   AR933X_UART_CS_PARITY_ODD	1
+#define   AR933X_UART_CS_PARITY_EVEN	2
 #define AR933X_UART_CS_IF_MODE_S	2
 #define AR933X_UART_CS_IF_MODE_M	0x3
+#define   AR933X_UART_CS_IF_MODE_NONE	0
+#define   AR933X_UART_CS_IF_MODE_DTE	1
+#define   AR933X_UART_CS_IF_MODE_DCE	2
 #define AR933X_UART_CS_FLOW_CTRL_S	4
 #define AR933X_UART_CS_FLOW_CTRL_M	0x3
 #define AR933X_UART_CS_DMA_EN		BIT(6)
@@ -41,7 +49,8 @@
 
 #define AR933X_UART_CLOCK_STEP_M	0xffff
 #define AR933X_UART_CLOCK_SCALE_M	0xfff
-#define AR933X_UART_CLCOK_SCALE_S	16
+#define AR933X_UART_CLOCK_SCALE_S	16
+#define AR933X_UART_CLOCK_STEP_M	0xffff
 
 #define AR933X_UART_INT_RX_VALID	BIT(0)
 #define AR933X_UART_INT_TX_READY	BIT(1)
diff --git a/target/linux/ar71xx/files/drivers/serial/ar933x_uart.c b/target/linux/ar71xx/files/drivers/serial/ar933x_uart.c
index 66925c9..ea12e40 100644
--- a/target/linux/ar71xx/files/drivers/serial/ar933x_uart.c
+++ b/target/linux/ar71xx/files/drivers/serial/ar933x_uart.c
@@ -1,27 +1,16 @@
 /*
- *  linux/drivers/serial/hornet_serial.c
+ *  Atheros AR933X SoC built-in UART driver
  *
- *  Driver for hornet serial ports
+ *  Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
  *
  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
  *
- *  Copyright (C) 2010 Ryan Hsu.
- *
- * 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.
- *
- *  $Id$
- *
- * A note about mapbase / membase
- *
- *  mapbase is the physical address of the IO port.
- *  membase is an 'ioremapped' cookie.
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 as published
+ *  by the Free Software Foundation.
  */
 
 #include <linux/module.h>
-#include <linux/moduleparam.h>
 #include <linux/ioport.h>
 #include <linux/init.h>
 #include <linux/console.h>
@@ -30,77 +19,26 @@
 #include <linux/platform_device.h>
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
-#include <linux/serial_reg.h>
 #include <linux/serial_core.h>
 #include <linux/serial.h>
-#include <linux/serial_8250.h>
-#include <linux/nmi.h>
-#include <linux/mutex.h>
 #include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/irq.h>
 
 #include <asm/mach-ar71xx/ar933x_uart.h>
 #include <asm/mach-ar71xx/ar933x_uart_platform.h>
 
-#include <asm/io.h>
-#include <asm/irq.h>
-
-#include "8250.h"
-#define ar7240_reg_rmw_clear(_reg, _val)	do {} while (0)
-
 #define DRIVER_NAME "ar933x-uart"
 
-#define AR933X_UART_REGS_SIZE	20
-#define AR933X_UART_FIFO_SIZE	16
-
-/*
- * uncomment below to enable WAR for EV81847.
- */
-//#define AR933X_EV81847_WAR
+#define AR933X_DUMMY_STATUS_RD	0x01
 
 static struct uart_driver ar933x_uart_driver;
 
-/*
- * Debugging.
- */
-#if 0
-#define DEBUG_AUTOCONF(fmt...)	printk(fmt)
-#else
-#define DEBUG_AUTOCONF(fmt...)	do { } while (0)
-#endif
-
-#if 0
-#define DEBUG_INTR(fmt...)	printk(fmt)
-#else
-#define DEBUG_INTR(fmt...)	do { } while (0)
-#endif
-
-/*
- * We default to IRQ0 for the "no irq" hack.   Some
- * machine types want others as well - they're free
- * to redefine this in their header file.
- */
-#define is_real_interrupt(irq)	((irq) != 0)
-
-#include <asm/serial.h>
-
 struct ar933x_uart_port {
 	struct uart_port	port;
-	struct timer_list	timer;		/* "no irq" timer */
-	unsigned char		acr;
-	unsigned char		ier;
-	unsigned char		lcr;
-	unsigned char		mcr;
+	unsigned int 		ier;	/* shadow Interrupt Enable Register */
 };
 
-static inline int ar933x_ev81847_war(void)
-{
-#if defined(AR933X_EV81847_WAR)
-	return 1;
-#else
-	return 0;
-#endif
-}
-
 static inline unsigned int ar933x_uart_read(struct ar933x_uart_port *up,
 					    int offset)
 {
@@ -142,19 +80,23 @@ static inline void ar933x_uart_rmw_clear(struct ar933x_uart_port *up,
 
 static inline void ar933x_uart_start_tx_interrupt(struct ar933x_uart_port *up)
 {
-	ar933x_uart_rmw_set(up, AR933X_UART_INT_EN_REG,
-			    AR933X_UART_INT_TX_EMPTY);
+	up->ier |= AR933X_UART_INT_TX_EMPTY;
+	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
 }
 
 static inline void ar933x_uart_stop_tx_interrupt(struct ar933x_uart_port *up)
 {
-	if (up->ier & UART_IER_THRI) {
-		up->ier &= ~UART_IER_THRI;
+	up->ier &= ~AR933X_UART_INT_TX_EMPTY;
+	ar933x_uart_write(up, AR933X_UART_INT_EN_REG,up->ier);
+}
 
-		/* FIXME: why this uses RXVALIDINTEN? */
-		ar933x_uart_rmw_clear(up, AR933X_UART_INT_EN_REG,
-				      AR933X_UART_INT_RX_VALID);
-	}
+static inline void ar933x_uart_putc(struct ar933x_uart_port *up, int ch)
+{
+	unsigned int rdata;
+
+	rdata = ch & AR933X_UART_DATA_TX_RX_MASK;
+	rdata |= AR933X_UART_DATA_TX_CSR;
+	ar933x_uart_write(up, AR933X_UART_DATA_REG, rdata);
 }
 
 static unsigned int ar933x_uart_tx_empty(struct uart_port *port)
@@ -197,34 +139,22 @@ static void ar933x_uart_stop_rx(struct uart_port *port)
 {
 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 
-	up->ier &= ~UART_IER_RLSI;
-	up->port.read_status_mask &= ~UART_LSR_DR;
-
-	ar933x_uart_rmw_clear(up, AR933X_UART_INT_EN_REG,
-			      AR933X_UART_INT_RX_VALID);
+	up->ier &= ~AR933X_UART_INT_RX_VALID;
+	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
 }
 
 static void ar933x_uart_break_ctl(struct uart_port *port, int break_state)
 {
 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 	unsigned long flags;
-	unsigned long rdata;
 
 	spin_lock_irqsave(&up->port.lock, flags);
-
 	if (break_state == -1)
-		up->lcr |= UART_LCR_SBC;
-	else
-		up->lcr &= ~UART_LCR_SBC;
-
-	rdata = ar933x_uart_read(up, AR933X_UART_CS_REG);
-	if (up->lcr & UART_LCR_SBC)
-		rdata |= AR933X_UART_CS_TX_BREAK;
+		ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
+				    AR933X_UART_CS_TX_BREAK);
 	else
-		rdata &= ~AR933X_UART_CS_TX_BREAK;
-
-	ar933x_uart_write(up, AR933X_UART_CS_REG, rdata);
-
+		ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
+				      AR933X_UART_CS_TX_BREAK);
 	spin_unlock_irqrestore(&up->port.lock, flags);
 }
 
@@ -232,395 +162,170 @@ static void ar933x_uart_enable_ms(struct uart_port *port)
 {
 }
 
-static inline unsigned int ar933x_uart_get_divisor(struct uart_port *port,
-						   unsigned int baud)
-{
-	return (port->uartclk / (16 * baud)) - 1;
-}
-
 static void ar933x_uart_set_termios(struct uart_port *port,
-				    struct ktermios *termios,
+				    struct ktermios *new,
 				    struct ktermios *old)
 {
 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
-	unsigned char cval;
+	unsigned int cs;
 	unsigned long flags;
-	unsigned int baud, quot;
-
-	switch (termios->c_cflag & CSIZE) {
-	case CS5:
-		cval = UART_LCR_WLEN5;
-		break;
-	case CS6:
-		cval = UART_LCR_WLEN6;
-		break;
-	case CS7:
-		cval = UART_LCR_WLEN7;
-		break;
-	default:
-	case CS8:
-		cval = UART_LCR_WLEN8;
-		break;
-	}
+	unsigned int baud, scale;
 
-	if (termios->c_cflag & CSTOPB)
-		cval |= UART_LCR_STOP;
-	if (termios->c_cflag & PARENB)
-		cval |= UART_LCR_PARITY;
-	if (!(termios->c_cflag & PARODD))
-		cval |= UART_LCR_EPAR;
-#ifdef CMSPAR
-	if (termios->c_cflag & CMSPAR)
-		cval |= UART_LCR_SPAR;
-#endif
+	/* Only CS8 is supported */
+	new->c_cflag &= ~CSIZE;
+	new->c_cflag |= CS8;
 
-	/*
-	 * Ask the core to calculate the divisor for us.
-	 */
-	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
-	quot = ar933x_uart_get_divisor(port, baud);
+	/* Only one stop bit is supported */
+	new->c_cflag &= ~CSTOPB;
 
-#if 0
-	if (up->capabilities & UART_CAP_FIFO && up->port.fifosize > 1) {
-		if (baud < 2400)
-			fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_1;
+	cs = 0;
+	if (new->c_cflag & PARENB) {
+		if (!(new->c_cflag & PARODD))
+			cs |= AR933X_UART_CS_PARITY_EVEN;
 		else
-			fcr = uart_config[up->port.type].fcr;
+			cs |= AR933X_UART_CS_PARITY_ODD;
+	} else {
+		cs |= AR933X_UART_CS_PARITY_NONE;
 	}
 
-	/*
-	 * MCR-based auto flow control.  When AFE is enabled, RTS will be
-	 * deasserted when the receive FIFO contains more characters than
-	 * the trigger, or the MCR RTS bit is cleared.  In the case where
-	 * the remote UART is not using CTS auto flow control, we must
-	 * have sufficient FIFO entries for the latency of the remote
-	 * UART to respond.  IOW, at least 32 bytes of FIFO.
-	 */
-	if (up->capabilities & UART_CAP_AFE && up->port.fifosize >= 32) {
-		up->mcr &= ~UART_MCR_AFE;
-		if (termios->c_cflag & CRTSCTS)
-			up->mcr |= UART_MCR_AFE;
-	}
-#endif
+	/* Mark/space parity is not supported */
+	new->c_cflag &= ~CMSPAR;
+
+	baud = uart_get_baud_rate(port, new, old, 0, port->uartclk / 16);
+	scale = (port->uartclk / (16 * baud)) - 1;
 
 	/*
-	 * Ok, we're now changing the port state.  Do it with
+	 * Ok, we're now changing the port state. Do it with
 	 * interrupts disabled.
 	 */
 	spin_lock_irqsave(&up->port.lock, flags);
 
-	/*
-	 * Update the per-port timeout.
-	 */
-	uart_update_timeout(port, termios->c_cflag, baud);
+	/* Update the per-port timeout. */
+	uart_update_timeout(port, new->c_cflag, baud);
 
-	up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
-	if (termios->c_iflag & INPCK)
-		up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
-	if (termios->c_iflag & (BRKINT | PARMRK))
-		up->port.read_status_mask |= UART_LSR_BI;
-
-	/*
-	 * Characteres to ignore
-	 */
 	up->port.ignore_status_mask = 0;
-	if (termios->c_iflag & IGNPAR)
-		up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
-	if (termios->c_iflag & IGNBRK) {
-		up->port.ignore_status_mask |= UART_LSR_BI;
-		/*
-		 * If we're ignoring parity and break indicators,
-		 * ignore overruns too (for real raw support).
-		 */
-		if (termios->c_iflag & IGNPAR)
-			up->port.ignore_status_mask |= UART_LSR_OE;
-	}
 
-	/*
-	 * ignore all characters if CREAD is not set
-	 */
-	if ((termios->c_cflag & CREAD) == 0)
-		up->port.ignore_status_mask |= UART_LSR_DR;
+	/* ignore all characters if CREAD is not set */
+	if ((new->c_cflag & CREAD) == 0)
+		up->port.ignore_status_mask |= AR933X_DUMMY_STATUS_RD;
 
-	/*
-	 * CTS flow control flag and modem status interrupts
-	 */
-	up->ier &= ~UART_IER_MSI;
-	if (UART_ENABLE_MS(&up->port, termios->c_cflag))
-		up->ier |= UART_IER_MSI;
+	ar933x_uart_write(up, AR933X_UART_CLOCK_REG,
+			  scale << AR933X_UART_CLOCK_SCALE_S | 8192);
+
+	/* setup configuration register */
+	ar933x_uart_rmw(up, AR933X_UART_CS_REG, AR933X_UART_CS_PARITY_M, cs);
 
+	/* enable host interrupt */
 	ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
 			    AR933X_UART_CS_HOST_INT_EN);
 
-	/* Save LCR */
-	up->lcr = cval;
-
-	ar933x_uart_set_mctrl(&up->port, up->port.mctrl);
 	spin_unlock_irqrestore(&up->port.lock, flags);
+
+	if (tty_termios_baud_rate(new))
+		tty_termios_encode_baud_rate(new, baud, baud);
 }
 
-static void ar933x_uart_rx_chars(struct ar933x_uart_port *up, int *status)
+static void ar933x_uart_rx_chars(struct ar933x_uart_port *up)
 {
 	struct tty_struct *tty = up->port.state->port.tty;
-	unsigned int lsr = *status;
-	unsigned char ch;
 	int max_count = 256;
-	char flag;
 
 	do {
-		ch = lsr & AR933X_UART_DATA_TX_RX_MASK;
+		unsigned int rdata;
+		unsigned char ch;
 
-		flag = TTY_NORMAL;
-		up->port.icount.rx++;
+		rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
+		if ((rdata & AR933X_UART_DATA_RX_CSR) == 0)
+			break;
 
-		lsr = AR933X_UART_DATA_RX_CSR;
-		ar933x_uart_write(up, AR933X_UART_DATA_REG, lsr);
-
-		if (unlikely(lsr & (UART_LSR_BI | UART_LSR_PE |
-				    UART_LSR_FE | UART_LSR_OE))) {
-			/*
-			 * For statistics only
-			 */
-			if (lsr & UART_LSR_BI) {
-				lsr &= ~(UART_LSR_FE | UART_LSR_PE);
-				up->port.icount.brk++;
-				/*
-				 * We do the SysRQ and SAK checking
-				 * here because otherwise the break
-				 * may get masked by ignore_status_mask
-				 * or read_status_mask.
-				 */
-				if (uart_handle_break(&up->port))
-					goto ignore_char;
-			} else if (lsr & UART_LSR_PE)
-				up->port.icount.parity++;
-			else if (lsr & UART_LSR_FE)
-				up->port.icount.frame++;
-			if (lsr & UART_LSR_OE)
-				up->port.icount.overrun++;
-
-			/*
-			 * Mask off conditions which should be ignored.
-			 */
-			lsr &= up->port.read_status_mask;
-
-			if (lsr & UART_LSR_BI) {
-				DEBUG_INTR("handling break....");
-				flag = TTY_BREAK;
-			} else if (lsr & UART_LSR_PE)
-				flag = TTY_PARITY;
-			else if (lsr & UART_LSR_FE)
-				flag = TTY_FRAME;
-		}
+		/* remove the character from the FIFO */
+		ar933x_uart_write(up, AR933X_UART_DATA_REG,
+				  AR933X_UART_DATA_RX_CSR);
 
-		if (uart_handle_sysrq_char(&up->port, ch))
-			goto ignore_char;
+		up->port.icount.rx++;
+		ch = rdata & AR933X_UART_DATA_TX_RX_MASK;
 
-		uart_insert_char(&up->port, lsr, UART_LSR_OE, ch, flag);
+		if (uart_handle_sysrq_char(&up->port, ch))
+			continue;
 
-ignore_char:
-		lsr = ar933x_uart_read(up, AR933X_UART_DATA_REG);
-	} while ((lsr & AR933X_UART_DATA_RX_CSR) && (max_count-- > 0));
+		if ((up->port.ignore_status_mask & AR933X_DUMMY_STATUS_RD) == 0)
+			tty_insert_flip_char(tty, ch, TTY_NORMAL);
+	} while (max_count-- > 0);
 
-	spin_unlock(&up->port.lock);
 	tty_flip_buffer_push(tty);
-	spin_lock(&up->port.lock);
-
-	*status = lsr;
 }
 
 static void ar933x_uart_tx_chars(struct ar933x_uart_port *up)
 {
 	struct circ_buf *xmit = &up->port.state->xmit;
 	int count;
-	unsigned int rdata;
-
-	rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
-	if ((rdata & AR933X_UART_DATA_TX_CSR) == 0) {
-		ar933x_uart_start_tx_interrupt(up);
-		return;
-	}
 
-	if (up->port.x_char) {
-		rdata = up->port.x_char & AR933X_UART_DATA_TX_RX_MASK;
-		rdata |= AR933X_UART_DATA_TX_CSR;
-		ar933x_uart_write(up, AR933X_UART_DATA_REG, rdata);
-		up->port.icount.tx++;
-		up->port.x_char = 0;
-		ar933x_uart_start_tx_interrupt(up);
+	if (uart_tx_stopped(&up->port))
 		return;
-	}
 
-	if (uart_tx_stopped(&up->port)) {
-		ar933x_uart_stop_tx(&up->port);
-		return;
-	}
-
-	if (uart_circ_empty(xmit)) {
-		ar933x_uart_stop_tx_interrupt(up);
-		return;
-	}
-
-	count = up->port.fifosize / 4;
+	count = up->port.fifosize;
 	do {
+		unsigned int rdata;
+
 		rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
-		if ((rdata & AR933X_UART_DATA_TX_CSR) == 0) {
-			ar933x_uart_start_tx_interrupt(up);
-			return;
+		if ((rdata & AR933X_UART_DATA_TX_CSR) == 0)
+			break;
+
+		if (up->port.x_char) {
+			ar933x_uart_putc(up, up->port.x_char);
+			up->port.icount.tx++;
+			up->port.x_char = 0;
+			continue;
 		}
 
-		rdata = xmit->buf[xmit->tail] & AR933X_UART_DATA_TX_RX_MASK;
-		rdata |= AR933X_UART_DATA_TX_CSR;
-		ar933x_uart_write(up, AR933X_UART_DATA_REG, rdata);
+		if (uart_circ_empty(xmit))
+			break;
+
+		ar933x_uart_putc(up, xmit->buf[xmit->tail]);
 
 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 		up->port.icount.tx++;
-		if (uart_circ_empty(xmit))
-			break;
 	} while (--count > 0);
 
-	rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
-	if ((rdata & AR933X_UART_DATA_TX_CSR) == 0) {
-		ar933x_uart_start_tx_interrupt(up);
-		return;
-	}
-
-	/* Re-enable TX Empty Interrupt to transmit pending chars */
-	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) {
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 		uart_write_wakeup(&up->port);
-		ar933x_uart_start_tx_interrupt(up);
-	}
 
-	DEBUG_INTR("THRE...");
-
-	if (uart_circ_empty(xmit))
-		ar933x_uart_stop_tx_interrupt(up);
-	else
+	if (!uart_circ_empty(xmit))
 		ar933x_uart_start_tx_interrupt(up);
 }
 
-/*! Hornet's interrupt status is not read clear, so that we have to...
- * a. read out the interrupt status
- * b. clear the interrupt mask to reset the interrupt status
- * c. enable the interrupt to reactivate interrupt
- *
- * Disable and clear the interrupt status
- */
-static inline void ar933x_uart_clear_int(struct ar933x_uart_port *up)
-{
-#define BIT3 (0x1>>3)
-
-	/* 1. clear MISC interrupt mask */
-	//ar7240_reg_rmw_clear(AR7240_MISC_INT_MASK, BIT3);
-
-	/* 2. clear uartcs hostinten mask, bit13 */
-	ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
-			      AR933X_UART_CS_HOST_INT_EN);
-
-	/* 3. clear rx uartint */
-	ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_RX_VALID);
-
-	/* 4. clear misc interrupt status  */
-	ar7240_reg_rmw_clear(AR7240_MISC_INT_STATUS, BIT3);
-
-	/* 5. clear rx uartinten*/
-	ar933x_uart_rmw_clear(up, AR933X_UART_INT_EN_REG,
-			      AR933X_UART_INT_RX_VALID);
-
-	/* 6. enable rx int*/
-	ar933x_uart_rmw_set(up, AR933X_UART_INT_EN_REG,
-			    AR933X_UART_INT_RX_VALID);
-
-	/* 7. set uartcs hostinten mask */
-	ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
-			    AR933X_UART_CS_HOST_INT_EN);
-
-	/* 8. set misc int mask */
-	//ar7240_reg_wr(AR7240_MISC_INT_MASK, BIT3);
-}
-
-static inline void ar933x_uart_handle_port(struct ar933x_uart_port *up)
+static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id)
 {
+	struct ar933x_uart_port *up = dev_id;
 	unsigned int status;
-	unsigned int int_status;
-	unsigned int en_status;
-	unsigned long flags;
 
-	status = ar933x_uart_read(up, AR933X_UART_DATA_REG);
-	int_status = ar933x_uart_read(up, AR933X_UART_INT_REG);
-	en_status = ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
+	status = ar933x_uart_read(up, AR933X_UART_CS_REG);
+	if ((status & AR933X_UART_CS_HOST_INT) == 0)
+		return IRQ_NONE;
 
-	spin_lock_irqsave(&up->port.lock, flags);
+	spin_lock(&up->port.lock);
 
-	if( (int_status & en_status) & AR933X_UART_INT_RX_VALID )
-		ar933x_uart_rx_chars(up, &status);
+	status = ar933x_uart_read(up, AR933X_UART_INT_REG);
+	status &= ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
 
-	if (((int_status & en_status) & AR933X_UART_INT_TX_EMPTY)) {
-		/* clear TX empty interrupts */
+	if (status & AR933X_UART_INT_RX_VALID) {
 		ar933x_uart_write(up, AR933X_UART_INT_REG,
-				  AR933X_UART_INT_TX_EMPTY);
-
-		/* disable TX empty interrupts */
-		ar933x_uart_rmw_clear(up, AR933X_UART_INT_EN_REG,
-				      AR933X_UART_INT_TX_EMPTY);
-
-		if (!uart_circ_empty(&up->port.state->xmit))
-			ar933x_uart_tx_chars(up);
+				  AR933X_UART_INT_RX_VALID);
+		ar933x_uart_rx_chars(up);
 	}
 
-	spin_unlock_irqrestore(&up->port.lock, flags);
-}
-
-static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id)
-{
-	struct ar933x_uart_port *up;
-	unsigned int iir;
-
-	up = (struct ar933x_uart_port *) dev_id;
-
-	iir = ar933x_uart_read(up, AR933X_UART_CS_REG);
-	if ((iir & AR933X_UART_CS_HOST_INT) == 0)
-		return IRQ_NONE;
-
-	DEBUG_INTR("ar933x_uart_interrupt(%d)...", irq);
+	if (status & AR933X_UART_INT_TX_EMPTY) {
+		ar933x_uart_write(up, AR933X_UART_INT_REG,
+				  AR933X_UART_INT_TX_EMPTY);
+		ar933x_uart_stop_tx_interrupt(up);
+		ar933x_uart_tx_chars(up);
+	}
 
-	spin_lock(&up->port.lock);
-	ar933x_uart_handle_port(up);
-	ar933x_uart_clear_int(up);
 	spin_unlock(&up->port.lock);
 
-	DEBUG_INTR("end.\n");
-
 	return IRQ_HANDLED;
 }
 
-static void ar933x_uart_timer(unsigned long data)
-{
-	struct uart_port *port = (void *)data;
-	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
-	unsigned int iir;
-
-	if (ar933x_ev81847_war()) {
-		struct circ_buf *xmit = &up->port.state->xmit;
-		unsigned long flags;
-
-		if (!uart_circ_empty(xmit)) {
-			spin_lock_irqsave(&up->port.lock, flags);
-			ar933x_uart_tx_chars(up);
-			spin_unlock_irqrestore(&up->port.lock, flags);
-		}
-	} else {
-		iir = ar933x_uart_read(up, AR933X_UART_CS_REG);
-		if (iir & AR933X_UART_CS_HOST_INT) {
-			spin_lock(&up->port.lock);
-			ar933x_uart_handle_port(up);
-			spin_unlock(&up->port.lock);
-		}
-	}
-
-	mod_timer(&up->timer, jiffies + uart_poll_timeout(port));
-}
-
 static int ar933x_uart_startup(struct uart_port *port)
 {
 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
@@ -632,39 +337,15 @@ static int ar933x_uart_startup(struct uart_port *port)
 	if (ret)
 		return ret;
 
-	up->mcr = 0;
-
-	/*
-	 * Clear the interrupt registers.
-	 */
-	ar933x_uart_read(up, AR933X_UART_CS_REG);
-	ar933x_uart_read(up, AR933X_UART_INT_REG);
-
-	if (!is_real_interrupt(up->port.irq) || ar933x_ev81847_war()) {
-		setup_timer(&up->timer, ar933x_uart_timer, (unsigned long)port);
-		mod_timer(&up->timer, jiffies + uart_poll_timeout(port));
-		return 0;
-	}
-
 	spin_lock_irqsave(&up->port.lock, flags);
 
-	/*
-	 * Enable host interrupts
-	 */
+	/* Enable HOST interrupts */
 	ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
 			    AR933X_UART_CS_HOST_INT_EN);
 
-	/*
-	 * Enable RX interrupts
-	 */
-	up->ier = UART_IER_RLSI | UART_IER_RDI;
-	ar933x_uart_write(up, AR933X_UART_INT_EN_REG,
-			  AR933X_UART_INT_RX_VALID);
-
-	/*
-	 * And clear the interrupt registers again for luck.
-	 */
-	ar933x_uart_read(up, AR933X_UART_INT_REG);
+	/* Enable RX interrupts */
+	up->ier = AR933X_UART_INT_RX_VALID;
+	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
 
 	spin_unlock_irqrestore(&up->port.lock, flags);
 
@@ -674,29 +355,15 @@ static int ar933x_uart_startup(struct uart_port *port)
 static void ar933x_uart_shutdown(struct uart_port *port)
 {
 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
-	unsigned long flags;
 
-	/*
-	 * Disable all interrupts from this port
-	 */
+	/* Disable all interrupts */
 	up->ier = 0;
-	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, 0);
-
-	spin_lock_irqsave(&up->port.lock, flags);
-	up->port.mctrl &= ~TIOCM_OUT2;
-	ar933x_uart_set_mctrl(&up->port, up->port.mctrl);
-	spin_unlock_irqrestore(&up->port.lock, flags);
+	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
 
-	/*
-	 * Disable break condition
-	 */
+	/* Disable break condition */
 	ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
 			      AR933X_UART_CS_TX_BREAK);
 
-	if (!is_real_interrupt(up->port.irq) ||
-	    ar933x_ev81847_war())
-		del_timer_sync(&up->timer);
-
 	free_irq(up->port.irq, up);
 }
 
@@ -718,20 +385,24 @@ static int ar933x_uart_request_port(struct uart_port *port)
 
 static void ar933x_uart_config_port(struct uart_port *port, int flags)
 {
-	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
-
-	port->type = PORT_AR933X;
-
-	/* Clear mask, so no surprise interrupts. */
-	ar933x_uart_read(up, AR933X_UART_CS_REG);
-	/* Clear interrupts status register */
-	ar933x_uart_read(up, AR933X_UART_INT_REG);
+	if (flags & UART_CONFIG_TYPE)
+		port->type = PORT_AR933X;
 }
 
 static int ar933x_uart_verify_port(struct uart_port *port,
 				   struct serial_struct *ser)
 {
-	return -EINVAL;
+	if (ser->type != PORT_UNKNOWN &&
+	    ser->type != PORT_AR933X)
+		return -EINVAL;
+
+	if (ser->irq < 0 || ser->irq >= NR_IRQS)
+		return -EINVAL;
+
+	if (ser->baud_base < 28800)
+		return -EINVAL;
+
+	return 0;
 }
 
 static struct uart_ops ar933x_uart_ops = {
@@ -774,13 +445,9 @@ static void ar933x_uart_wait_xmitr(struct ar933x_uart_port *up)
 static void ar933x_uart_console_putchar(struct uart_port *port, int ch)
 {
 	struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
-	unsigned int rdata;
 
 	ar933x_uart_wait_xmitr(up);
-
-	rdata = ch & AR933X_UART_DATA_TX_RX_MASK;
-	rdata |= AR933X_UART_DATA_TX_CSR;
-	ar933x_uart_write(up, AR933X_UART_DATA_REG, rdata);
+	ar933x_uart_putc(up, ch);
 }
 
 static void ar933x_uart_console_write(struct console *co, const char *s,
@@ -788,22 +455,22 @@ static void ar933x_uart_console_write(struct console *co, const char *s,
 {
 	struct ar933x_uart_port *up = ar933x_console_ports[co->index];
 	unsigned long flags;
-	unsigned int ier;
+	unsigned int int_en;
 	int locked = 1;
 
 	local_irq_save(flags);
 
-	if (up->port.sysrq) {
+	if (up->port.sysrq)
 		locked = 0;
-	} else if (oops_in_progress) {
+	else if (oops_in_progress)
 		locked = spin_trylock(&up->port.lock);
-	} else
+	else
 		spin_lock(&up->port.lock);
 
 	/*
 	 * First save the IER then disable the interrupts
 	 */
-	ier = ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
+	int_en = ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
 	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, 0);
 
 	uart_console_write(&up->port, s, count, ar933x_uart_console_putchar);
@@ -813,8 +480,8 @@ static void ar933x_uart_console_write(struct console *co, const char *s,
 	 * and restore the IER
 	 */
 	ar933x_uart_wait_xmitr(up);
+	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, int_en);
 
-	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, ier);
 	ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_ALLINTS);
 
 	if (locked)
@@ -854,13 +521,6 @@ static struct console ar933x_uart_console = {
 	.data		= &ar933x_uart_driver,
 };
 
-static int __init ar933x_uart_console_init(void)
-{
-	register_console(&ar933x_uart_console);
-	return 0;
-}
-console_initcall(ar933x_uart_console_init);
-
 static void ar933x_uart_add_console_port(struct ar933x_uart_port *up)
 {
 	ar933x_console_ports[up->port.line] = up;
@@ -1015,4 +675,4 @@ module_exit(ar933x_uart_exit);
 MODULE_DESCRIPTION("Atheros AR933X UART driver");
 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 MODULE_LICENSE("GPL v2");
-MODULE_ALIAS("platform:" DRV_NAME);
+MODULE_ALIAS("platform:" DRIVER_NAME);