drivers/tty/serial/timbuart.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * timbuart.c timberdale FPGA UART driver
  * Copyright (c) 2009 Intel Corporation
  */

 /* Supports:
  * Timberdale FPGA UART
  */

 #include <linux/pci.h>
 #include <linux/interrupt.h>
 #include <linux/serial_core.h>
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
 #include <linux/kernel.h>
 #include <linux/platform_device.h>
 #include <linux/ioport.h>
 #include <linux/slab.h>
 #include <linux/module.h>

 #include "timbuart.h"

 struct timbuart_port {
 	struct uart_port	port;
 	struct tasklet_struct	tasklet;
 	int			usedma;
 	u32			last_ier;
 	struct platform_device  *dev;
 };

 static int baudrates[] = {9600, 19200, 38400, 57600, 115200, 230400, 460800,
 	921600, 1843200, 3250000};

 static void timbuart_mctrl_check(struct uart_port *port, u32 isr, u32 *ier);

 static irqreturn_t timbuart_handleinterrupt(int irq, void *devid);

 static void timbuart_stop_rx(struct uart_port *port)
 {
 	/* spin lock held by upper layer, disable all RX interrupts */
 	u32 ier = ioread32(port->membase + TIMBUART_IER) & ~RXFLAGS;
 	iowrite32(ier, port->membase + TIMBUART_IER);
 }

 static void timbuart_stop_tx(struct uart_port *port)
 {
 	/* spinlock held by upper layer, disable TX interrupt */
 	u32 ier = ioread32(port->membase + TIMBUART_IER) & ~TXBAE;
 	iowrite32(ier, port->membase + TIMBUART_IER);
 }

 static void timbuart_start_tx(struct uart_port *port)
 {
 	struct timbuart_port *uart =
 		container_of(port, struct timbuart_port, port);

 	/* do not transfer anything here -> fire off the tasklet */
 	tasklet_schedule(&uart->tasklet);
 }

 static unsigned int timbuart_tx_empty(struct uart_port *port)
 {
 	u32 isr = ioread32(port->membase + TIMBUART_ISR);

 	return (isr & TXBE) ? TIOCSER_TEMT : 0;
 }

 static void timbuart_flush_buffer(struct uart_port *port)
 {
 	if (!timbuart_tx_empty(port)) {
 		u8 ctl = ioread8(port->membase + TIMBUART_CTRL) |
 			TIMBUART_CTRL_FLSHTX;

 		iowrite8(ctl, port->membase + TIMBUART_CTRL);
 		iowrite32(TXBF, port->membase + TIMBUART_ISR);
 	}
 }

 static void timbuart_rx_chars(struct uart_port *port)
 {
 	struct tty_port *tport = &port->state->port;

 	while (ioread32(port->membase + TIMBUART_ISR) & RXDP) {
 		u8 ch = ioread8(port->membase + TIMBUART_RXFIFO);
 		port->icount.rx++;
 		tty_insert_flip_char(tport, ch, TTY_NORMAL);
 	}

 	tty_flip_buffer_push(tport);

 	dev_dbg(port->dev, "%s - total read %d bytes\n",
 		__func__, port->icount.rx);
 }

 static void timbuart_tx_chars(struct uart_port *port)
 {
 	struct circ_buf *xmit = &port->state->xmit;

 	while (!(ioread32(port->membase + TIMBUART_ISR) & TXBF) &&
 		!uart_circ_empty(xmit)) {
 		iowrite8(xmit->buf[xmit->tail],
 			port->membase + TIMBUART_TXFIFO);
 		uart_xmit_advance(port, 1);
 	}

 	dev_dbg(port->dev,
 		"%s - total written %d bytes, CTL: %x, RTS: %x, baud: %x\n",
 		 __func__,
 		port->icount.tx,
 		ioread8(port->membase + TIMBUART_CTRL),
 		port->mctrl & TIOCM_RTS,
 		ioread8(port->membase + TIMBUART_BAUDRATE));
 }

 static void timbuart_handle_tx_port(struct uart_port *port, u32 isr, u32 *ier)
 {
 	struct timbuart_port *uart =
 		container_of(port, struct timbuart_port, port);
 	struct circ_buf *xmit = &port->state->xmit;

 	if (uart_circ_empty(xmit) || uart_tx_stopped(port))
 		return;

 	if (port->x_char)
 		return;

 	if (isr & TXFLAGS) {
 		timbuart_tx_chars(port);
 		/* clear all TX interrupts */
 		iowrite32(TXFLAGS, port->membase + TIMBUART_ISR);

 		if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 			uart_write_wakeup(port);
 	} else
 		/* Re-enable any tx interrupt */
 		*ier |= uart->last_ier & TXFLAGS;

 	/* enable interrupts if there are chars in the transmit buffer,
 	 * Or if we delivered some bytes and want the almost empty interrupt
 	 * we wake up the upper layer later when we got the interrupt
 	 * to give it some time to go out...
 	 */
 	if (!uart_circ_empty(xmit))
 		*ier |= TXBAE;

 	dev_dbg(port->dev, "%s - leaving\n", __func__);
 }

 static void timbuart_handle_rx_port(struct uart_port *port, u32 isr, u32 *ier)
 {
 	if (isr & RXFLAGS) {
 		/* Some RX status is set */
 		if (isr & RXBF) {
 			u8 ctl = ioread8(port->membase + TIMBUART_CTRL) |
 				TIMBUART_CTRL_FLSHRX;
 			iowrite8(ctl, port->membase + TIMBUART_CTRL);
 			port->icount.overrun++;
 		} else if (isr & (RXDP))
 			timbuart_rx_chars(port);

 		/* ack all RX interrupts */
 		iowrite32(RXFLAGS, port->membase + TIMBUART_ISR);
 	}

 	/* always have the RX interrupts enabled */
 	*ier |= RXBAF | RXBF | RXTT;

 	dev_dbg(port->dev, "%s - leaving\n", __func__);
 }

 static void timbuart_tasklet(struct tasklet_struct *t)
 {
 	struct timbuart_port *uart = from_tasklet(uart, t, tasklet);
 	u32 isr, ier = 0;

 	spin_lock(&uart->port.lock);

 	isr = ioread32(uart->port.membase + TIMBUART_ISR);
 	dev_dbg(uart->port.dev, "%s ISR: %x\n", __func__, isr);

 	if (!uart->usedma)
 		timbuart_handle_tx_port(&uart->port, isr, &ier);

 	timbuart_mctrl_check(&uart->port, isr, &ier);

 	if (!uart->usedma)
 		timbuart_handle_rx_port(&uart->port, isr, &ier);

 	iowrite32(ier, uart->port.membase + TIMBUART_IER);

 	spin_unlock(&uart->port.lock);
 	dev_dbg(uart->port.dev, "%s leaving\n", __func__);
 }

 static unsigned int timbuart_get_mctrl(struct uart_port *port)
 {
 	u8 cts = ioread8(port->membase + TIMBUART_CTRL);
 	dev_dbg(port->dev, "%s - cts %x\n", __func__, cts);

 	if (cts & TIMBUART_CTRL_CTS)
 		return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
 	else
 		return TIOCM_DSR | TIOCM_CAR;
 }

 static void timbuart_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
 	dev_dbg(port->dev, "%s - %x\n", __func__, mctrl);

 	if (mctrl & TIOCM_RTS)
 		iowrite8(TIMBUART_CTRL_RTS, port->membase + TIMBUART_CTRL);
 	else
 		iowrite8(0, port->membase + TIMBUART_CTRL);
 }

 static void timbuart_mctrl_check(struct uart_port *port, u32 isr, u32 *ier)
 {
 	unsigned int cts;

 	if (isr & CTS_DELTA) {
 		/* ack */
 		iowrite32(CTS_DELTA, port->membase + TIMBUART_ISR);
 		cts = timbuart_get_mctrl(port);
 		uart_handle_cts_change(port, cts & TIOCM_CTS);
 		wake_up_interruptible(&port->state->port.delta_msr_wait);
 	}

 	*ier |= CTS_DELTA;
 }

 static void timbuart_break_ctl(struct uart_port *port, int ctl)
 {
 	/* N/A */
 }

 static int timbuart_startup(struct uart_port *port)
 {
 	struct timbuart_port *uart =
 		container_of(port, struct timbuart_port, port);

 	dev_dbg(port->dev, "%s\n", __func__);

 	iowrite8(TIMBUART_CTRL_FLSHRX, port->membase + TIMBUART_CTRL);
 	iowrite32(0x1ff, port->membase + TIMBUART_ISR);
 	/* Enable all but TX interrupts */
 	iowrite32(RXBAF | RXBF | RXTT | CTS_DELTA,
 		port->membase + TIMBUART_IER);

 	return request_irq(port->irq, timbuart_handleinterrupt, IRQF_SHARED,
 		"timb-uart", uart);
 }

 static void timbuart_shutdown(struct uart_port *port)
 {
 	struct timbuart_port *uart =
 		container_of(port, struct timbuart_port, port);
 	dev_dbg(port->dev, "%s\n", __func__);
 	free_irq(port->irq, uart);
 	iowrite32(0, port->membase + TIMBUART_IER);

 	timbuart_flush_buffer(port);
 }

 static int get_bindex(int baud)
 {
 	int i;

 	for (i = 0; i < ARRAY_SIZE(baudrates); i++)
 		if (baud <= baudrates[i])
 			return i;

 	return -1;
 }

 static void timbuart_set_termios(struct uart_port *port,
 				 struct ktermios *termios,
 				 const struct ktermios *old)
 {
 	unsigned int baud;
 	short bindex;
 	unsigned long flags;

 	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
 	bindex = get_bindex(baud);
 	dev_dbg(port->dev, "%s - bindex %d\n", __func__, bindex);

 	if (bindex < 0)
 		bindex = 0;
 	baud = baudrates[bindex];

 	/* The serial layer calls into this once with old = NULL when setting
 	   up initially */
 	if (old)
 		tty_termios_copy_hw(termios, old);
 	tty_termios_encode_baud_rate(termios, baud, baud);

 	spin_lock_irqsave(&port->lock, flags);
 	iowrite8((u8)bindex, port->membase + TIMBUART_BAUDRATE);
 	uart_update_timeout(port, termios->c_cflag, baud);
 	spin_unlock_irqrestore(&port->lock, flags);
 }

 static const char *timbuart_type(struct uart_port *port)
 {
 	return port->type == PORT_UNKNOWN ? "timbuart" : NULL;
 }

 /* We do not request/release mappings of the registers here,
  * currently it's done in the proble function.
  */
 static void timbuart_release_port(struct uart_port *port)
 {
 	struct platform_device *pdev = to_platform_device(port->dev);
 	int size =
 		resource_size(platform_get_resource(pdev, IORESOURCE_MEM, 0));

 	if (port->flags & UPF_IOREMAP) {
 		iounmap(port->membase);
 		port->membase = NULL;
 	}

 	release_mem_region(port->mapbase, size);
 }

 static int timbuart_request_port(struct uart_port *port)
 {
 	struct platform_device *pdev = to_platform_device(port->dev);
 	int size =
 		resource_size(platform_get_resource(pdev, IORESOURCE_MEM, 0));

 	if (!request_mem_region(port->mapbase, size, "timb-uart"))
 		return -EBUSY;

 	if (port->flags & UPF_IOREMAP) {
 		port->membase = ioremap(port->mapbase, size);
 		if (port->membase == NULL) {
 			release_mem_region(port->mapbase, size);
 			return -ENOMEM;
 		}
 	}

 	return 0;
 }

 static irqreturn_t timbuart_handleinterrupt(int irq, void *devid)
 {
 	struct timbuart_port *uart = (struct timbuart_port *)devid;

 	if (ioread8(uart->port.membase + TIMBUART_IPR)) {
 		uart->last_ier = ioread32(uart->port.membase + TIMBUART_IER);

 		/* disable interrupts, the tasklet enables them again */
 		iowrite32(0, uart->port.membase + TIMBUART_IER);

 		/* fire off bottom half */
 		tasklet_schedule(&uart->tasklet);

 		return IRQ_HANDLED;
 	} else
 		return IRQ_NONE;
 }

 /*
  * Configure/autoconfigure the port.
  */
 static void timbuart_config_port(struct uart_port *port, int flags)
 {
 	if (flags & UART_CONFIG_TYPE) {
 		port->type = PORT_TIMBUART;
 		timbuart_request_port(port);
 	}
 }

 static int timbuart_verify_port(struct uart_port *port,
 	struct serial_struct *ser)
 {
 	/* we don't want the core code to modify any port params */
 	return -EINVAL;
 }

 static const struct uart_ops timbuart_ops = {
 	.tx_empty = timbuart_tx_empty,
 	.set_mctrl = timbuart_set_mctrl,
 	.get_mctrl = timbuart_get_mctrl,
 	.stop_tx = timbuart_stop_tx,
 	.start_tx = timbuart_start_tx,
 	.flush_buffer = timbuart_flush_buffer,
 	.stop_rx = timbuart_stop_rx,
 	.break_ctl = timbuart_break_ctl,
 	.startup = timbuart_startup,
 	.shutdown = timbuart_shutdown,
 	.set_termios = timbuart_set_termios,
 	.type = timbuart_type,
 	.release_port = timbuart_release_port,
 	.request_port = timbuart_request_port,
 	.config_port = timbuart_config_port,
 	.verify_port = timbuart_verify_port
 };

 static struct uart_driver timbuart_driver = {
 	.owner = THIS_MODULE,
 	.driver_name = "timberdale_uart",
 	.dev_name = "ttyTU",
 	.major = TIMBUART_MAJOR,
 	.minor = TIMBUART_MINOR,
 	.nr = 1
 };

 static int timbuart_probe(struct platform_device *dev)
 {
 	int err, irq;
 	struct timbuart_port *uart;
 	struct resource *iomem;

 	dev_dbg(&dev->dev, "%s\n", __func__);

 	uart = kzalloc(sizeof(*uart), GFP_KERNEL);
 	if (!uart) {
 		err = -EINVAL;
 		goto err_mem;
 	}

 	uart->usedma = 0;

 	uart->port.uartclk = 3250000 * 16;
 	uart->port.fifosize  = TIMBUART_FIFO_SIZE;
 	uart->port.regshift  = 2;
 	uart->port.iotype  = UPIO_MEM;
 	uart->port.ops = &timbuart_ops;
 	uart->port.irq = 0;
 	uart->port.flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP;
 	uart->port.line  = 0;
 	uart->port.dev	= &dev->dev;

 	iomem = platform_get_resource(dev, IORESOURCE_MEM, 0);
 	if (!iomem) {
 		err = -ENOMEM;
 		goto err_register;
 	}
 	uart->port.mapbase = iomem->start;
 	uart->port.membase = NULL;

 	irq = platform_get_irq(dev, 0);
 	if (irq < 0) {
 		err = -EINVAL;
 		goto err_register;
 	}
 	uart->port.irq = irq;

 	tasklet_setup(&uart->tasklet, timbuart_tasklet);

 	err = uart_register_driver(&timbuart_driver);
 	if (err)
 		goto err_register;

 	err = uart_add_one_port(&timbuart_driver, &uart->port);
 	if (err)
 		goto err_add_port;

 	platform_set_drvdata(dev, uart);

 	return 0;

 err_add_port:
 	uart_unregister_driver(&timbuart_driver);
 err_register:
 	kfree(uart);
 err_mem:
 	printk(KERN_ERR "timberdale: Failed to register Timberdale UART: %d\n",
 		err);

 	return err;
 }

 static int timbuart_remove(struct platform_device *dev)
 {
 	struct timbuart_port *uart = platform_get_drvdata(dev);

 	tasklet_kill(&uart->tasklet);
 	uart_remove_one_port(&timbuart_driver, &uart->port);
 	uart_unregister_driver(&timbuart_driver);
 	kfree(uart);

 	return 0;
 }

 static struct platform_driver timbuart_platform_driver = {
 	.driver = {
 		.name	= "timb-uart",
 	},
 	.probe		= timbuart_probe,
 	.remove		= timbuart_remove,
 };

 module_platform_driver(timbuart_platform_driver);

 MODULE_DESCRIPTION("Timberdale UART driver");
 MODULE_LICENSE("GPL v2");
 MODULE_ALIAS("platform:timb-uart");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* timbuart.c timberdale FPGA UART driver
	* Copyright (c) 2009 Intel Corporation
	*/

	/* Supports:
	* Timberdale FPGA UART
	*/

	#include <linux/pci.h>
	#include <linux/interrupt.h>
	#include <linux/serial_core.h>
	#include <linux/tty.h>
	#include <linux/tty_flip.h>
	#include <linux/kernel.h>
	#include <linux/platform_device.h>
	#include <linux/ioport.h>
	#include <linux/slab.h>
	#include <linux/module.h>

	#include "timbuart.h"

	struct timbuart_port {
	struct uart_port port;
	struct tasklet_struct tasklet;
	int usedma;
	u32 last_ier;
	struct platform_device *dev;
	};

	static int baudrates[] = {9600, 19200, 38400, 57600, 115200, 230400, 460800,
	921600, 1843200, 3250000};

	static void timbuart_mctrl_check(struct uart_port port, u32 isr, u32 ier);

	static irqreturn_t timbuart_handleinterrupt(int irq, void *devid);

	static void timbuart_stop_rx(struct uart_port *port)
	{
	/* spin lock held by upper layer, disable all RX interrupts */
	u32 ier = ioread32(port->membase + TIMBUART_IER) & ~RXFLAGS;
	iowrite32(ier, port->membase + TIMBUART_IER);
	}

	static void timbuart_stop_tx(struct uart_port *port)
	{
	/* spinlock held by upper layer, disable TX interrupt */
	u32 ier = ioread32(port->membase + TIMBUART_IER) & ~TXBAE;
	iowrite32(ier, port->membase + TIMBUART_IER);
	}

	static void timbuart_start_tx(struct uart_port *port)
	{
	struct timbuart_port *uart =
	container_of(port, struct timbuart_port, port);

	/* do not transfer anything here -> fire off the tasklet */
	tasklet_schedule(&uart->tasklet);
	}

	static unsigned int timbuart_tx_empty(struct uart_port *port)
	{
	u32 isr = ioread32(port->membase + TIMBUART_ISR);

	return (isr & TXBE) ? TIOCSER_TEMT : 0;
	}

	static void timbuart_flush_buffer(struct uart_port *port)
	{
	if (!timbuart_tx_empty(port)) {
	u8 ctl = ioread8(port->membase + TIMBUART_CTRL) \|
	TIMBUART_CTRL_FLSHTX;

	iowrite8(ctl, port->membase + TIMBUART_CTRL);
	iowrite32(TXBF, port->membase + TIMBUART_ISR);
	}
	}

	static void timbuart_rx_chars(struct uart_port *port)
	{
	struct tty_port *tport = &port->state->port;

	while (ioread32(port->membase + TIMBUART_ISR) & RXDP) {
	u8 ch = ioread8(port->membase + TIMBUART_RXFIFO);
	port->icount.rx++;
	tty_insert_flip_char(tport, ch, TTY_NORMAL);
	}

	tty_flip_buffer_push(tport);

	dev_dbg(port->dev, "%s - total read %d bytes\n",
	__func__, port->icount.rx);
	}

	static void timbuart_tx_chars(struct uart_port *port)
	{
	struct circ_buf *xmit = &port->state->xmit;

	while (!(ioread32(port->membase + TIMBUART_ISR) & TXBF) &&
	!uart_circ_empty(xmit)) {
	iowrite8(xmit->buf[xmit->tail],
	port->membase + TIMBUART_TXFIFO);
	uart_xmit_advance(port, 1);
	}

	dev_dbg(port->dev,
	"%s - total written %d bytes, CTL: %x, RTS: %x, baud: %x\n",
	__func__,
	port->icount.tx,
	ioread8(port->membase + TIMBUART_CTRL),
	port->mctrl & TIOCM_RTS,
	ioread8(port->membase + TIMBUART_BAUDRATE));
	}

	static void timbuart_handle_tx_port(struct uart_port port, u32 isr, u32 ier)
	{
	struct timbuart_port *uart =
	container_of(port, struct timbuart_port, port);
	struct circ_buf *xmit = &port->state->xmit;

	if (uart_circ_empty(xmit) \|\| uart_tx_stopped(port))
	return;

	if (port->x_char)
	return;

	if (isr & TXFLAGS) {
	timbuart_tx_chars(port);
	/* clear all TX interrupts */
	iowrite32(TXFLAGS, port->membase + TIMBUART_ISR);

	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
	uart_write_wakeup(port);
	} else
	/* Re-enable any tx interrupt */
	*ier \|= uart->last_ier & TXFLAGS;

	/* enable interrupts if there are chars in the transmit buffer,
	* Or if we delivered some bytes and want the almost empty interrupt
	* we wake up the upper layer later when we got the interrupt
	* to give it some time to go out...
	*/
	if (!uart_circ_empty(xmit))
	*ier \|= TXBAE;

	dev_dbg(port->dev, "%s - leaving\n", __func__);
	}

	static void timbuart_handle_rx_port(struct uart_port port, u32 isr, u32 ier)
	{
	if (isr & RXFLAGS) {
	/* Some RX status is set */
	if (isr & RXBF) {
	u8 ctl = ioread8(port->membase + TIMBUART_CTRL) \|
	TIMBUART_CTRL_FLSHRX;
	iowrite8(ctl, port->membase + TIMBUART_CTRL);
	port->icount.overrun++;
	} else if (isr & (RXDP))
	timbuart_rx_chars(port);

	/* ack all RX interrupts */
	iowrite32(RXFLAGS, port->membase + TIMBUART_ISR);
	}

	/* always have the RX interrupts enabled */
	*ier \|= RXBAF \| RXBF \| RXTT;

	dev_dbg(port->dev, "%s - leaving\n", __func__);
	}

	static void timbuart_tasklet(struct tasklet_struct *t)
	{
	struct timbuart_port *uart = from_tasklet(uart, t, tasklet);
	u32 isr, ier = 0;

	spin_lock(&uart->port.lock);

	isr = ioread32(uart->port.membase + TIMBUART_ISR);
	dev_dbg(uart->port.dev, "%s ISR: %x\n", __func__, isr);

	if (!uart->usedma)
	timbuart_handle_tx_port(&uart->port, isr, &ier);

	timbuart_mctrl_check(&uart->port, isr, &ier);

	if (!uart->usedma)
	timbuart_handle_rx_port(&uart->port, isr, &ier);

	iowrite32(ier, uart->port.membase + TIMBUART_IER);

	spin_unlock(&uart->port.lock);
	dev_dbg(uart->port.dev, "%s leaving\n", __func__);
	}

	static unsigned int timbuart_get_mctrl(struct uart_port *port)
	{
	u8 cts = ioread8(port->membase + TIMBUART_CTRL);
	dev_dbg(port->dev, "%s - cts %x\n", __func__, cts);

	if (cts & TIMBUART_CTRL_CTS)
	return TIOCM_CTS \| TIOCM_DSR \| TIOCM_CAR;
	else
	return TIOCM_DSR \| TIOCM_CAR;
	}

	static void timbuart_set_mctrl(struct uart_port *port, unsigned int mctrl)
	{
	dev_dbg(port->dev, "%s - %x\n", __func__, mctrl);

	if (mctrl & TIOCM_RTS)
	iowrite8(TIMBUART_CTRL_RTS, port->membase + TIMBUART_CTRL);
	else
	iowrite8(0, port->membase + TIMBUART_CTRL);
	}

	static void timbuart_mctrl_check(struct uart_port port, u32 isr, u32 ier)
	{
	unsigned int cts;

	if (isr & CTS_DELTA) {
	/* ack */
	iowrite32(CTS_DELTA, port->membase + TIMBUART_ISR);
	cts = timbuart_get_mctrl(port);
	uart_handle_cts_change(port, cts & TIOCM_CTS);
	wake_up_interruptible(&port->state->port.delta_msr_wait);
	}

	*ier \|= CTS_DELTA;
	}

	static void timbuart_break_ctl(struct uart_port *port, int ctl)
	{
	/* N/A */
	}

	static int timbuart_startup(struct uart_port *port)
	{
	struct timbuart_port *uart =
	container_of(port, struct timbuart_port, port);

	dev_dbg(port->dev, "%s\n", __func__);

	iowrite8(TIMBUART_CTRL_FLSHRX, port->membase + TIMBUART_CTRL);
	iowrite32(0x1ff, port->membase + TIMBUART_ISR);
	/* Enable all but TX interrupts */
	iowrite32(RXBAF \| RXBF \| RXTT \| CTS_DELTA,
	port->membase + TIMBUART_IER);

	return request_irq(port->irq, timbuart_handleinterrupt, IRQF_SHARED,
	"timb-uart", uart);
	}

	static void timbuart_shutdown(struct uart_port *port)
	{
	struct timbuart_port *uart =
	container_of(port, struct timbuart_port, port);
	dev_dbg(port->dev, "%s\n", __func__);
	free_irq(port->irq, uart);
	iowrite32(0, port->membase + TIMBUART_IER);

	timbuart_flush_buffer(port);
	}

	static int get_bindex(int baud)
	{
	int i;

	for (i = 0; i < ARRAY_SIZE(baudrates); i++)
	if (baud <= baudrates[i])
	return i;

	return -1;
	}

	static void timbuart_set_termios(struct uart_port *port,
	struct ktermios *termios,
	const struct ktermios *old)
	{
	unsigned int baud;
	short bindex;
	unsigned long flags;

	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
	bindex = get_bindex(baud);
	dev_dbg(port->dev, "%s - bindex %d\n", __func__, bindex);

	if (bindex < 0)
	bindex = 0;
	baud = baudrates[bindex];

	/* The serial layer calls into this once with old = NULL when setting
	up initially */
	if (old)
	tty_termios_copy_hw(termios, old);
	tty_termios_encode_baud_rate(termios, baud, baud);

	spin_lock_irqsave(&port->lock, flags);
	iowrite8((u8)bindex, port->membase + TIMBUART_BAUDRATE);
	uart_update_timeout(port, termios->c_cflag, baud);
	spin_unlock_irqrestore(&port->lock, flags);
	}

	static const char timbuart_type(struct uart_port port)
	{
	return port->type == PORT_UNKNOWN ? "timbuart" : NULL;
	}

	/* We do not request/release mappings of the registers here,
	* currently it's done in the proble function.
	*/
	static void timbuart_release_port(struct uart_port *port)
	{
	struct platform_device *pdev = to_platform_device(port->dev);
	int size =
	resource_size(platform_get_resource(pdev, IORESOURCE_MEM, 0));

	if (port->flags & UPF_IOREMAP) {
	iounmap(port->membase);
	port->membase = NULL;
	}

	release_mem_region(port->mapbase, size);
	}

	static int timbuart_request_port(struct uart_port *port)
	{
	struct platform_device *pdev = to_platform_device(port->dev);
	int size =
	resource_size(platform_get_resource(pdev, IORESOURCE_MEM, 0));

	if (!request_mem_region(port->mapbase, size, "timb-uart"))
	return -EBUSY;

	if (port->flags & UPF_IOREMAP) {
	port->membase = ioremap(port->mapbase, size);
	if (port->membase == NULL) {
	release_mem_region(port->mapbase, size);
	return -ENOMEM;
	}
	}

	return 0;
	}

	static irqreturn_t timbuart_handleinterrupt(int irq, void *devid)
	{
	struct timbuart_port uart = (struct timbuart_port )devid;

	if (ioread8(uart->port.membase + TIMBUART_IPR)) {
	uart->last_ier = ioread32(uart->port.membase + TIMBUART_IER);

	/* disable interrupts, the tasklet enables them again */
	iowrite32(0, uart->port.membase + TIMBUART_IER);

	/* fire off bottom half */
	tasklet_schedule(&uart->tasklet);

	return IRQ_HANDLED;
	} else
	return IRQ_NONE;
	}

	/*
	* Configure/autoconfigure the port.
	*/
	static void timbuart_config_port(struct uart_port *port, int flags)
	{
	if (flags & UART_CONFIG_TYPE) {
	port->type = PORT_TIMBUART;
	timbuart_request_port(port);
	}
	}

	static int timbuart_verify_port(struct uart_port *port,
	struct serial_struct *ser)
	{
	/* we don't want the core code to modify any port params */
	return -EINVAL;
	}

	static const struct uart_ops timbuart_ops = {
	.tx_empty = timbuart_tx_empty,
	.set_mctrl = timbuart_set_mctrl,
	.get_mctrl = timbuart_get_mctrl,
	.stop_tx = timbuart_stop_tx,
	.start_tx = timbuart_start_tx,
	.flush_buffer = timbuart_flush_buffer,
	.stop_rx = timbuart_stop_rx,
	.break_ctl = timbuart_break_ctl,
	.startup = timbuart_startup,
	.shutdown = timbuart_shutdown,
	.set_termios = timbuart_set_termios,
	.type = timbuart_type,
	.release_port = timbuart_release_port,
	.request_port = timbuart_request_port,
	.config_port = timbuart_config_port,
	.verify_port = timbuart_verify_port
	};

	static struct uart_driver timbuart_driver = {
	.owner = THIS_MODULE,
	.driver_name = "timberdale_uart",
	.dev_name = "ttyTU",
	.major = TIMBUART_MAJOR,
	.minor = TIMBUART_MINOR,
	.nr = 1
	};

	static int timbuart_probe(struct platform_device *dev)
	{
	int err, irq;
	struct timbuart_port *uart;
	struct resource *iomem;

	dev_dbg(&dev->dev, "%s\n", __func__);

	uart = kzalloc(sizeof(*uart), GFP_KERNEL);
	if (!uart) {
	err = -EINVAL;
	goto err_mem;
	}

	uart->usedma = 0;

	uart->port.uartclk = 3250000 * 16;
	uart->port.fifosize = TIMBUART_FIFO_SIZE;
	uart->port.regshift = 2;
	uart->port.iotype = UPIO_MEM;
	uart->port.ops = &timbuart_ops;
	uart->port.irq = 0;
	uart->port.flags = UPF_BOOT_AUTOCONF \| UPF_IOREMAP;
	uart->port.line = 0;
	uart->port.dev = &dev->dev;

	iomem = platform_get_resource(dev, IORESOURCE_MEM, 0);
	if (!iomem) {
	err = -ENOMEM;
	goto err_register;
	}
	uart->port.mapbase = iomem->start;
	uart->port.membase = NULL;

	irq = platform_get_irq(dev, 0);
	if (irq < 0) {
	err = -EINVAL;
	goto err_register;
	}
	uart->port.irq = irq;

	tasklet_setup(&uart->tasklet, timbuart_tasklet);

	err = uart_register_driver(&timbuart_driver);
	if (err)
	goto err_register;

	err = uart_add_one_port(&timbuart_driver, &uart->port);
	if (err)
	goto err_add_port;

	platform_set_drvdata(dev, uart);

	return 0;

	err_add_port:
	uart_unregister_driver(&timbuart_driver);
	err_register:
	kfree(uart);
	err_mem:
	printk(KERN_ERR "timberdale: Failed to register Timberdale UART: %d\n",
	err);

	return err;
	}

	static int timbuart_remove(struct platform_device *dev)
	{
	struct timbuart_port *uart = platform_get_drvdata(dev);

	tasklet_kill(&uart->tasklet);
	uart_remove_one_port(&timbuart_driver, &uart->port);
	uart_unregister_driver(&timbuart_driver);
	kfree(uart);

	return 0;
	}

	static struct platform_driver timbuart_platform_driver = {
	.driver = {
	.name = "timb-uart",
	},
	.probe = timbuart_probe,
	.remove = timbuart_remove,
	};

	module_platform_driver(timbuart_platform_driver);

	MODULE_DESCRIPTION("Timberdale UART driver");
	MODULE_LICENSE("GPL v2");
	MODULE_ALIAS("platform:timb-uart");