[ARM] 3242/2: AT91RM9200 support for 2.6 (Serial)

Patch from Andrew Victor

This patch adds support to the 2.6 kernel series for the Atmel
AT91RM9200 processor.

This patch is the Serial driver.

This version uses the newly re-written GPL'ed hardware headers.

Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 894 insertions, 0 deletions

diff --git a/drivers/serial/at91_serial.c b/drivers/serial/at91_serial.c
new file mode 100644
index 0000000..0e20606
--- /dev/null
+++ b/drivers/serial/at91_serial.c
@@ -0,0 +1,894 @@
+/*
+ *  linux/drivers/char/at91_serial.c
+ *
+ *  Driver for Atmel AT91RM9200 Serial ports
+ *
+ *  Copyright (C) 2003 Rick Bronson
+ *
+ *  Based on drivers/char/serial_sa1100.c, by Deep Blue Solutions Ltd.
+ *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/tty.h>
+#include <linux/ioport.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/serial.h>
+#include <linux/console.h>
+#include <linux/sysrq.h>
+#include <linux/tty_flip.h>
+
+#include <asm/io.h>
+
+#include <asm/arch/at91rm9200_usart.h>
+#include <asm/mach/serial_at91rm9200.h>
+#include <asm/arch/board.h>
+#include <asm/arch/pio.h>
+
+
+#if defined(CONFIG_SERIAL_AT91_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
+#include <linux/serial_core.h>
+
+#ifdef CONFIG_SERIAL_AT91_TTYAT
+
+/* Use device name ttyAT, major 204 and minor 154-169.  This is necessary if we
+ * should coexist with the 8250 driver, such as if we have an external 16C550
+ * UART. */
+#define SERIAL_AT91_MAJOR	204
+#define MINOR_START		154
+#define AT91_DEVICENAME		"ttyAT"
+
+#else
+
+/* Use device name ttyS, major 4, minor 64-68.  This is the usual serial port
+ * name, but it is legally reserved for the 8250 driver. */
+#define SERIAL_AT91_MAJOR	TTY_MAJOR
+#define MINOR_START		64
+#define AT91_DEVICENAME		"ttyS"
+
+#endif
+
+#define AT91_VA_BASE_DBGU	((unsigned long) AT91_VA_BASE_SYS + AT91_DBGU)
+#define AT91_ISR_PASS_LIMIT	256
+
+#define UART_PUT_CR(port,v)	writel(v, (port)->membase + AT91_US_CR)
+#define UART_GET_MR(port)	readl((port)->membase + AT91_US_MR)
+#define UART_PUT_MR(port,v)	writel(v, (port)->membase + AT91_US_MR)
+#define UART_PUT_IER(port,v)	writel(v, (port)->membase + AT91_US_IER)
+#define UART_PUT_IDR(port,v)	writel(v, (port)->membase + AT91_US_IDR)
+#define UART_GET_IMR(port)	readl((port)->membase + AT91_US_IMR)
+#define UART_GET_CSR(port)	readl((port)->membase + AT91_US_CSR)
+#define UART_GET_CHAR(port)	readl((port)->membase + AT91_US_RHR)
+#define UART_PUT_CHAR(port,v)	writel(v, (port)->membase + AT91_US_THR)
+#define UART_GET_BRGR(port)	readl((port)->membase + AT91_US_BRGR)
+#define UART_PUT_BRGR(port,v)	writel(v, (port)->membase + AT91_US_BRGR)
+#define UART_PUT_RTOR(port,v)	writel(v, (port)->membase + AT91_US_RTOR)
+
+// #define UART_GET_CR(port)	readl((port)->membase + AT91_US_CR)		// is write-only
+
+ /* PDC registers */
+#define UART_PUT_PTCR(port,v)	writel(v, (port)->membase + AT91_PDC_PTCR)
+#define UART_PUT_RPR(port,v)	writel(v, (port)->membase + AT91_PDC_RPR)
+#define UART_PUT_RCR(port,v)	writel(v, (port)->membase + AT91_PDC_RCR)
+#define UART_GET_RCR(port)	readl((port)->membase + AT91_PDC_RCR)
+#define UART_PUT_RNPR(port,v)	writel(v, (port)->membase + AT91_PDC_RNPR)
+#define UART_PUT_RNCR(port,v)	writel(v, (port)->membase + AT91_PDC_RNCR)
+
+
+static int (*at91_open)(struct uart_port *);
+static void (*at91_close)(struct uart_port *);
+
+#ifdef SUPPORT_SYSRQ
+static struct console at91_console;
+#endif
+
+/*
+ * Return TIOCSER_TEMT when transmitter FIFO and Shift register is empty.
+ */
+static u_int at91_tx_empty(struct uart_port *port)
+{
+	return (UART_GET_CSR(port) & AT91_US_TXEMPTY) ? TIOCSER_TEMT : 0;
+}
+
+/*
+ * Set state of the modem control output lines
+ */
+static void at91_set_mctrl(struct uart_port *port, u_int mctrl)
+{
+	unsigned int control = 0;
+
+	/*
+	 * Errata #39: RTS0 is not internally connected to PA21.  We need to drive
+	 *  the pin manually.
+	 */
+	if (port->mapbase == AT91_VA_BASE_US0) {
+		if (mctrl & TIOCM_RTS)
+			at91_sys_write(AT91_PIOA + PIO_CODR, AT91_PA21_RTS0);
+		else
+			at91_sys_write(AT91_PIOA + PIO_SODR, AT91_PA21_RTS0);
+	}
+
+	if (mctrl & TIOCM_RTS)
+		control |= AT91_US_RTSEN;
+	else
+		control |= AT91_US_RTSDIS;
+
+	if (mctrl & TIOCM_DTR)
+		control |= AT91_US_DTREN;
+	else
+		control |= AT91_US_DTRDIS;
+
+	UART_PUT_CR(port,control);
+}
+
+/*
+ * Get state of the modem control input lines
+ */
+static u_int at91_get_mctrl(struct uart_port *port)
+{
+	unsigned int status, ret = 0;
+
+	status = UART_GET_CSR(port);
+
+	/*
+	 * The control signals are active low.
+	 */
+	if (!(status & AT91_US_DCD))
+		ret |= TIOCM_CD;
+	if (!(status & AT91_US_CTS))
+		ret |= TIOCM_CTS;
+	if (!(status & AT91_US_DSR))
+		ret |= TIOCM_DSR;
+	if (!(status & AT91_US_RI))
+		ret |= TIOCM_RI;
+
+	return ret;
+}
+
+/*
+ * Stop transmitting.
+ */
+static void at91_stop_tx(struct uart_port *port)
+{
+	UART_PUT_IDR(port, AT91_US_TXRDY);
+	port->read_status_mask &= ~AT91_US_TXRDY;
+}
+
+/*
+ * Start transmitting.
+ */
+static void at91_start_tx(struct uart_port *port)
+{
+	port->read_status_mask |= AT91_US_TXRDY;
+	UART_PUT_IER(port, AT91_US_TXRDY);
+}
+
+/*
+ * Stop receiving - port is in process of being closed.
+ */
+static void at91_stop_rx(struct uart_port *port)
+{
+	UART_PUT_IDR(port, AT91_US_RXRDY);
+}
+
+/*
+ * Enable modem status interrupts
+ */
+static void at91_enable_ms(struct uart_port *port)
+{
+	port->read_status_mask |= (AT91_US_RIIC | AT91_US_DSRIC | AT91_US_DCDIC | AT91_US_CTSIC);
+	UART_PUT_IER(port, AT91_US_RIIC | AT91_US_DSRIC | AT91_US_DCDIC | AT91_US_CTSIC);
+}
+
+/*
+ * Control the transmission of a break signal
+ */
+static void at91_break_ctl(struct uart_port *port, int break_state)
+{
+	if (break_state != 0)
+		UART_PUT_CR(port, AT91_US_STTBRK);	/* start break */
+	else
+		UART_PUT_CR(port, AT91_US_STPBRK);	/* stop break */
+}
+
+/*
+ * Characters received (called from interrupt handler)
+ */
+static void at91_rx_chars(struct uart_port *port, struct pt_regs *regs)
+{
+	struct tty_struct *tty = port->info->tty;
+	unsigned int status, ch, flg;
+
+	status = UART_GET_CSR(port) & port->read_status_mask;
+	while (status & (AT91_US_RXRDY)) {
+		ch = UART_GET_CHAR(port);
+
+		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
+			goto ignore_char;
+		port->icount.rx++;
+
+		flg = TTY_NORMAL;
+
+		/*
+		 * note that the error handling code is
+		 * out of the main execution path
+		 */
+		if (unlikely(status & (AT91_US_PARE | AT91_US_FRAME | AT91_US_OVRE))) {
+			UART_PUT_CR(port, AT91_US_RSTSTA);	/* clear error */
+			if (status & (AT91_US_PARE))
+				port->icount.parity++;
+			if (status & (AT91_US_FRAME))
+				port->icount.frame++;
+			if (status & (AT91_US_OVRE))
+				port->icount.overrun++;
+
+			if (status & AT91_US_PARE)
+				flg = TTY_PARITY;
+			else if (status & AT91_US_FRAME)
+				flg = TTY_FRAME;
+			if (status & AT91_US_OVRE) {
+				/*
+				 * overrun does *not* affect the character
+				 * we read from the FIFO
+				 */
+				tty_insert_flip_char(tty, ch, flg);
+				ch = 0;
+				flg = TTY_OVERRUN;
+			}
+#ifdef SUPPORT_SYSRQ
+			port->sysrq = 0;
+#endif
+		}
+
+		if (uart_handle_sysrq_char(port, ch, regs))
+			goto ignore_char;
+
+		tty_insert_flip_char(tty, ch, flg);
+
+	ignore_char:
+		status = UART_GET_CSR(port) & port->read_status_mask;
+	}
+
+	tty_flip_buffer_push(tty);
+}
+
+/*
+ * Transmit characters (called from interrupt handler)
+ */
+static void at91_tx_chars(struct uart_port *port)
+{
+	struct circ_buf *xmit = &port->info->xmit;
+
+	if (port->x_char) {
+		UART_PUT_CHAR(port, port->x_char);
+		port->icount.tx++;
+		port->x_char = 0;
+		return;
+	}
+	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
+		at91_stop_tx(port);
+		return;
+	}
+
+	while (UART_GET_CSR(port) & AT91_US_TXRDY) {
+		UART_PUT_CHAR(port, xmit->buf[xmit->tail]);
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		port->icount.tx++;
+		if (uart_circ_empty(xmit))
+			break;
+	}
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+
+	if (uart_circ_empty(xmit))
+		at91_stop_tx(port);
+}
+
+/*
+ * Interrupt handler
+ */
+static irqreturn_t at91_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+	struct uart_port *port = dev_id;
+	unsigned int status, pending, pass_counter = 0;
+
+	status = UART_GET_CSR(port);
+	pending = status & port->read_status_mask;
+	if (pending) {
+		do {
+			if (pending & AT91_US_RXRDY)
+				at91_rx_chars(port, regs);
+
+			/* Clear the relevent break bits */
+			if (pending & AT91_US_RXBRK) {
+				UART_PUT_CR(port, AT91_US_RSTSTA);
+				port->icount.brk++;
+				uart_handle_break(port);
+			}
+
+			// TODO: All reads to CSR will clear these interrupts!
+			if (pending & AT91_US_RIIC) port->icount.rng++;
+			if (pending & AT91_US_DSRIC) port->icount.dsr++;
+			if (pending & AT91_US_DCDIC)
+				uart_handle_dcd_change(port, !(status & AT91_US_DCD));
+			if (pending & AT91_US_CTSIC)
+				uart_handle_cts_change(port, !(status & AT91_US_CTS));
+			if (pending & (AT91_US_RIIC | AT91_US_DSRIC | AT91_US_DCDIC | AT91_US_CTSIC))
+				wake_up_interruptible(&port->info->delta_msr_wait);
+
+			if (pending & AT91_US_TXRDY)
+				at91_tx_chars(port);
+			if (pass_counter++ > AT91_ISR_PASS_LIMIT)
+				break;
+
+			status = UART_GET_CSR(port);
+			pending = status & port->read_status_mask;
+		} while (pending);
+	}
+	return IRQ_HANDLED;
+}
+
+/*
+ * Perform initialization and enable port for reception
+ */
+static int at91_startup(struct uart_port *port)
+{
+	int retval;
+
+	/*
+	 * Ensure that no interrupts are enabled otherwise when
+	 * request_irq() is called we could get stuck trying to
+	 * handle an unexpected interrupt
+	 */
+	UART_PUT_IDR(port, -1);
+
+	/*
+	 * Allocate the IRQ
+	 */
+	retval = request_irq(port->irq, at91_interrupt, SA_SHIRQ, "at91_serial", port);
+	if (retval) {
+		printk("at91_serial: at91_startup - Can't get irq\n");
+		return retval;
+	}
+
+	/*
+	 * If there is a specific "open" function (to register
+	 * control line interrupts)
+	 */
+	if (at91_open) {
+		retval = at91_open(port);
+		if (retval) {
+			free_irq(port->irq, port);
+			return retval;
+		}
+	}
+
+	port->read_status_mask = AT91_US_RXRDY | AT91_US_TXRDY | AT91_US_OVRE
+			| AT91_US_FRAME | AT91_US_PARE | AT91_US_RXBRK;
+	/*
+	 * Finally, enable the serial port
+	 */
+	UART_PUT_CR(port, AT91_US_RSTSTA | AT91_US_RSTRX);
+	UART_PUT_CR(port, AT91_US_TXEN | AT91_US_RXEN);		/* enable xmit & rcvr */
+	UART_PUT_IER(port, AT91_US_RXRDY);			/* do receive only */
+	return 0;
+}
+
+/*
+ * Disable the port
+ */
+static void at91_shutdown(struct uart_port *port)
+{
+	/*
+	 * Disable all interrupts, port and break condition.
+	 */
+	UART_PUT_CR(port, AT91_US_RSTSTA);
+	UART_PUT_IDR(port, -1);
+
+	/*
+	 * Free the interrupt
+	 */
+	free_irq(port->irq, port);
+
+	/*
+	 * If there is a specific "close" function (to unregister
+	 * control line interrupts)
+	 */
+	if (at91_close)
+		at91_close(port);
+}
+
+/*
+ * Power / Clock management.
+ */
+static void at91_serial_pm(struct uart_port *port, unsigned int state, unsigned int oldstate)
+{
+	switch (state) {
+		case 0:
+			/*
+			 * Enable the peripheral clock for this serial port.
+			 * This is called on uart_open() or a resume event.
+			 */
+			at91_sys_write(AT91_PMC_PCER, 1 << port->irq);
+			break;
+		case 3:
+			/*
+			 * Disable the peripheral clock for this serial port.
+			 * This is called on uart_close() or a suspend event.
+			 */
+			if (port->irq != AT91_ID_SYS)			/* is this a shared clock? */
+				at91_sys_write(AT91_PMC_PCDR, 1 << port->irq);
+			break;
+		default:
+			printk(KERN_ERR "at91_serial: unknown pm %d\n", state);
+	}
+}
+
+/*
+ * Change the port parameters
+ */
+static void at91_set_termios(struct uart_port *port, struct termios * termios, struct termios * old)
+{
+	unsigned long flags;
+	unsigned int mode, imr, quot, baud;
+
+	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
+	quot = uart_get_divisor(port, baud);
+
+	/* Get current mode register */
+	mode = UART_GET_MR(port) & ~(AT91_US_CHRL | AT91_US_NBSTOP | AT91_US_PAR);
+
+	/* byte size */
+	switch (termios->c_cflag & CSIZE) {
+	case CS5:
+		mode |= AT91_US_CHRL_5;
+		break;
+	case CS6:
+		mode |= AT91_US_CHRL_6;
+		break;
+	case CS7:
+		mode |= AT91_US_CHRL_7;
+		break;
+	default:
+		mode |= AT91_US_CHRL_8;
+		break;
+	}
+
+	/* stop bits */
+	if (termios->c_cflag & CSTOPB)
+		mode |= AT91_US_NBSTOP_2;
+
+	/* parity */
+	if (termios->c_cflag & PARENB) {
+		if (termios->c_cflag & CMSPAR) {			/* Mark or Space parity */
+			if (termios->c_cflag & PARODD)
+				mode |= AT91_US_PAR_MARK;
+			else
+				mode |= AT91_US_PAR_SPACE;
+		}
+		else if (termios->c_cflag & PARODD)
+			mode |= AT91_US_PAR_ODD;
+		else
+			mode |= AT91_US_PAR_EVEN;
+	}
+	else
+		mode |= AT91_US_PAR_NONE;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	port->read_status_mask |= AT91_US_OVRE;
+	if (termios->c_iflag & INPCK)
+		port->read_status_mask |= AT91_US_FRAME | AT91_US_PARE;
+	if (termios->c_iflag & (BRKINT | PARMRK))
+		port->read_status_mask |= AT91_US_RXBRK;
+
+	/*
+	 * Characters to ignore
+	 */
+	port->ignore_status_mask = 0;
+	if (termios->c_iflag & IGNPAR)
+		port->ignore_status_mask |= (AT91_US_FRAME | AT91_US_PARE);
+	if (termios->c_iflag & IGNBRK) {
+		port->ignore_status_mask |= AT91_US_RXBRK;
+		/*
+		 * If we're ignoring parity and break indicators,
+		 * ignore overruns too (for real raw support).
+		 */
+		if (termios->c_iflag & IGNPAR)
+			port->ignore_status_mask |= AT91_US_OVRE;
+	}
+
+	// TODO: Ignore all characters if CREAD is set.
+
+	/* update the per-port timeout */
+	uart_update_timeout(port, termios->c_cflag, baud);
+
+	/* disable interrupts and drain transmitter */
+	imr = UART_GET_IMR(port);	/* get interrupt mask */
+	UART_PUT_IDR(port, -1);		/* disable all interrupts */
+	while (!(UART_GET_CSR(port) & AT91_US_TXEMPTY)) { barrier(); }
+
+	/* disable receiver and transmitter */
+	UART_PUT_CR(port, AT91_US_TXDIS | AT91_US_RXDIS);
+
+	/* set the parity, stop bits and data size */
+	UART_PUT_MR(port, mode);
+
+	/* set the baud rate */
+	UART_PUT_BRGR(port, quot);
+	UART_PUT_CR(port, AT91_US_RSTSTA | AT91_US_RSTRX);
+	UART_PUT_CR(port, AT91_US_TXEN | AT91_US_RXEN);
+
+	/* restore interrupts */
+	UART_PUT_IER(port, imr);
+
+	/* CTS flow-control and modem-status interrupts */
+	if (UART_ENABLE_MS(port, termios->c_cflag))
+		port->ops->enable_ms(port);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+/*
+ * Return string describing the specified port
+ */
+static const char *at91_type(struct uart_port *port)
+{
+	return (port->type == PORT_AT91RM9200) ? "AT91_SERIAL" : NULL;
+}
+
+/*
+ * Release the memory region(s) being used by 'port'.
+ */
+static void at91_release_port(struct uart_port *port)
+{
+	release_mem_region(port->mapbase,
+		(port->mapbase == AT91_VA_BASE_DBGU) ? 512 : SZ_16K);
+}
+
+/*
+ * Request the memory region(s) being used by 'port'.
+ */
+static int at91_request_port(struct uart_port *port)
+{
+	return request_mem_region(port->mapbase,
+		(port->mapbase == AT91_VA_BASE_DBGU) ? 512 : SZ_16K,
+		"at91_serial") != NULL ? 0 : -EBUSY;
+
+}
+
+/*
+ * Configure/autoconfigure the port.
+ */
+static void at91_config_port(struct uart_port *port, int flags)
+{
+	if (flags & UART_CONFIG_TYPE) {
+		port->type = PORT_AT91RM9200;
+		at91_request_port(port);
+	}
+}
+
+/*
+ * Verify the new serial_struct (for TIOCSSERIAL).
+ */
+static int at91_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+	int ret = 0;
+	if (ser->type != PORT_UNKNOWN && ser->type != PORT_AT91RM9200)
+		ret = -EINVAL;
+	if (port->irq != ser->irq)
+		ret = -EINVAL;
+	if (ser->io_type != SERIAL_IO_MEM)
+		ret = -EINVAL;
+	if (port->uartclk / 16 != ser->baud_base)
+		ret = -EINVAL;
+	if ((void *)port->mapbase != ser->iomem_base)
+		ret = -EINVAL;
+	if (port->iobase != ser->port)
+		ret = -EINVAL;
+	if (ser->hub6 != 0)
+		ret = -EINVAL;
+	return ret;
+}
+
+static struct uart_ops at91_pops = {
+	.tx_empty	= at91_tx_empty,
+	.set_mctrl	= at91_set_mctrl,
+	.get_mctrl	= at91_get_mctrl,
+	.stop_tx	= at91_stop_tx,
+	.start_tx	= at91_start_tx,
+	.stop_rx	= at91_stop_rx,
+	.enable_ms	= at91_enable_ms,
+	.break_ctl	= at91_break_ctl,
+	.startup	= at91_startup,
+	.shutdown	= at91_shutdown,
+	.set_termios	= at91_set_termios,
+	.type		= at91_type,
+	.release_port	= at91_release_port,
+	.request_port	= at91_request_port,
+	.config_port 	= at91_config_port,
+	.verify_port 	= at91_verify_port,
+	.pm		= at91_serial_pm,
+};
+
+static struct uart_port at91_ports[AT91_NR_UART];
+
+void __init at91_init_ports(void)
+{
+	static int first = 1;
+	int i;
+
+	if (!first)
+		return;
+	first = 0;
+
+	for (i = 0; i < AT91_NR_UART; i++) {
+		at91_ports[i].iotype	= UPIO_MEM;
+		at91_ports[i].flags     = UPF_BOOT_AUTOCONF;
+		at91_ports[i].uartclk   = at91_master_clock;
+		at91_ports[i].ops	= &at91_pops;
+		at91_ports[i].fifosize  = 1;
+		at91_ports[i].line	= i;
+ 	}
+}
+
+void __init at91_register_uart_fns(struct at91rm9200_port_fns *fns)
+{
+	if (fns->enable_ms)
+		at91_pops.enable_ms = fns->enable_ms;
+	if (fns->get_mctrl)
+		at91_pops.get_mctrl = fns->get_mctrl;
+	if (fns->set_mctrl)
+		at91_pops.set_mctrl = fns->set_mctrl;
+	at91_open          = fns->open;
+	at91_close         = fns->close;
+	at91_pops.pm       = fns->pm;
+	at91_pops.set_wake = fns->set_wake;
+}
+
+/*
+ * Setup ports.
+ */
+void __init at91_register_uart(int idx, int port)
+{
+	if ((idx < 0) || (idx >= AT91_NR_UART)) {
+		printk(KERN_ERR "%s: bad index number %d\n", __FUNCTION__, idx);
+		return;
+	}
+
+	switch (port) {
+	case 0:
+		at91_ports[idx].membase = (void __iomem *) AT91_VA_BASE_US0;
+		at91_ports[idx].mapbase = AT91_VA_BASE_US0;
+		at91_ports[idx].irq     = AT91_ID_US0;
+		AT91_CfgPIO_USART0();
+		break;
+	case 1:
+		at91_ports[idx].membase = (void __iomem *) AT91_VA_BASE_US1;
+		at91_ports[idx].mapbase = AT91_VA_BASE_US1;
+		at91_ports[idx].irq     = AT91_ID_US1;
+		AT91_CfgPIO_USART1();
+		break;
+	case 2:
+		at91_ports[idx].membase = (void __iomem *) AT91_VA_BASE_US2;
+		at91_ports[idx].mapbase = AT91_VA_BASE_US2;
+		at91_ports[idx].irq     = AT91_ID_US2;
+		AT91_CfgPIO_USART2();
+		break;
+	case 3:
+		at91_ports[idx].membase = (void __iomem *) AT91_VA_BASE_US3;
+		at91_ports[idx].mapbase = AT91_VA_BASE_US3;
+		at91_ports[idx].irq     = AT91_ID_US3;
+		AT91_CfgPIO_USART3();
+		break;
+	case 4:
+		at91_ports[idx].membase = (void __iomem *) AT91_VA_BASE_DBGU;
+		at91_ports[idx].mapbase = AT91_VA_BASE_DBGU;
+		at91_ports[idx].irq     = AT91_ID_SYS;
+		AT91_CfgPIO_DBGU();
+		break;
+	default:
+		printk(KERN_ERR  "%s : bad port number %d\n", __FUNCTION__, port);
+	}
+}
+
+#ifdef CONFIG_SERIAL_AT91_CONSOLE
+
+/*
+ * Interrupts are disabled on entering
+ */
+static void at91_console_write(struct console *co, const char *s, u_int count)
+{
+	struct uart_port *port = at91_ports + co->index;
+	unsigned int status, i, imr;
+
+	/*
+	 *	First, save IMR and then disable interrupts
+	 */
+	imr = UART_GET_IMR(port);	/* get interrupt mask */
+	UART_PUT_IDR(port, AT91_US_RXRDY | AT91_US_TXRDY);
+
+	/*
+	 *	Now, do each character
+	 */
+	for (i = 0; i < count; i++) {
+		do {
+			status = UART_GET_CSR(port);
+		} while (!(status & AT91_US_TXRDY));
+		UART_PUT_CHAR(port, s[i]);
+		if (s[i] == '\n') {
+			do {
+				status = UART_GET_CSR(port);
+			} while (!(status & AT91_US_TXRDY));
+			UART_PUT_CHAR(port, '\r');
+		}
+	}
+
+	/*
+	 *	Finally, wait for transmitter to become empty
+	 *	and restore IMR
+	 */
+	do {
+		status = UART_GET_CSR(port);
+	} while (!(status & AT91_US_TXRDY));
+	UART_PUT_IER(port, imr);	/* set interrupts back the way they were */
+}
+
+/*
+ * If the port was already initialised (eg, by a boot loader), try to determine
+ * the current setup.
+ */
+static void __init at91_console_get_options(struct uart_port *port, int *baud, int *parity, int *bits)
+{
+	unsigned int mr, quot;
+
+// TODO: CR is a write-only register
+//	unsigned int cr;
+//
+//	cr = UART_GET_CR(port) & (AT91_US_RXEN | AT91_US_TXEN);
+//	if (cr == (AT91_US_RXEN | AT91_US_TXEN)) {
+//		/* ok, the port was enabled */
+//	}
+
+	mr = UART_GET_MR(port) & AT91_US_CHRL;
+	if (mr == AT91_US_CHRL_8)
+		*bits = 8;
+	else
+		*bits = 7;
+
+	mr = UART_GET_MR(port) & AT91_US_PAR;
+	if (mr == AT91_US_PAR_EVEN)
+		*parity = 'e';
+	else if (mr == AT91_US_PAR_ODD)
+		*parity = 'o';
+
+	quot = UART_GET_BRGR(port);
+	*baud = port->uartclk / (16 * (quot));
+}
+
+static int __init at91_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.
+	 */
+	port = uart_get_console(at91_ports, AT91_NR_UART, co);
+
+	/*
+	 * Enable the serial console, in-case bootloader did not do it.
+	 */
+	at91_sys_write(AT91_PMC_PCER, 1 << port->irq);	/* enable clock */
+	UART_PUT_IDR(port, -1);				/* disable interrupts */
+	UART_PUT_CR(port, AT91_US_RSTSTA | AT91_US_RSTRX);
+	UART_PUT_CR(port, AT91_US_TXEN | AT91_US_RXEN);
+
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+	else
+		at91_console_get_options(port, &baud, &parity, &bits);
+
+	return uart_set_options(port, co, baud, parity, bits, flow);
+}
+
+static struct uart_driver at91_uart;
+
+static struct console at91_console = {
+	.name		= AT91_DEVICENAME,
+	.write		= at91_console_write,
+	.device		= uart_console_device,
+	.setup		= at91_console_setup,
+	.flags		= CON_PRINTBUFFER,
+	.index		= -1,
+	.data		= &at91_uart,
+};
+
+#define AT91_CONSOLE_DEVICE	&at91_console
+
+static int  __init at91_console_init(void)
+{
+	at91_init_ports();
+
+	at91_console.index = at91_console_port;
+	register_console(&at91_console);
+	return 0;
+}
+console_initcall(at91_console_init);
+
+#else
+#define AT91_CONSOLE_DEVICE	NULL
+#endif
+
+static struct uart_driver at91_uart = {
+	.owner			= THIS_MODULE,
+	.driver_name		= AT91_DEVICENAME,
+	.dev_name		= AT91_DEVICENAME,
+	.devfs_name		= AT91_DEVICENAME,
+	.major			= SERIAL_AT91_MAJOR,
+	.minor			= MINOR_START,
+	.nr			= AT91_NR_UART,
+	.cons			= AT91_CONSOLE_DEVICE,
+};
+
+static int __init at91_serial_init(void)
+{
+	int ret, i;
+
+	at91_init_ports();
+
+	ret = uart_register_driver(&at91_uart);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < AT91_NR_UART; i++) {
+		if (at91_serial_map[i] >= 0)
+			uart_add_one_port(&at91_uart, &at91_ports[i]);
+	}
+
+	return 0;
+}
+
+static void __exit at91_serial_exit(void)
+{
+	int i;
+
+	for (i = 0; i < AT91_NR_UART; i++) {
+ 		if (at91_serial_map[i] >= 0)
+			uart_remove_one_port(&at91_uart, &at91_ports[i]);
+  	}
+
+	uart_unregister_driver(&at91_uart);
+}
+
+module_init(at91_serial_init);
+module_exit(at91_serial_exit);
+
+MODULE_AUTHOR("Rick Bronson");
+MODULE_DESCRIPTION("AT91 generic serial port driver");
+MODULE_LICENSE("GPL");