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Commit 34aec591 authored by Richard Röjfors's avatar Richard Röjfors Committed by Linus Torvalds
Browse files

serial: Added Timberdale UART driver 



Driver for the UART found in the Timberdale FPGA

Signed-off-by: default avatarRichard Röjfors <richard.rojfors.ext@mocean-labs.com>
Signed-off-by: default avatarAlan Cox <alan@linux.intel.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e960bf73

drivers/serial/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -1433,4 +1433,11 @@ config SPORT_BAUD_RATE 
	default 19200 if (SERIAL_SPORT_BAUD_RATE_19200)

	default 9600 if (SERIAL_SPORT_BAUD_RATE_9600)



config SERIAL_TIMBERDALE

	tristate "Support for timberdale UART"

	depends on MFD_TIMBERDALE

	select SERIAL_CORE

	---help---

	Add support for UART controller on timberdale.



endmenu

drivers/serial/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -77,3 +77,4 @@ obj-$(CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL) += nwpserial.o 
obj-$(CONFIG_SERIAL_KS8695) += serial_ks8695.o

obj-$(CONFIG_KGDB_SERIAL_CONSOLE) += kgdboc.o

obj-$(CONFIG_SERIAL_QE) += ucc_uart.o

obj-$(CONFIG_SERIAL_TIMBERDALE)	+= timbuart.o

drivers/serial/timbuart.c

0 → 100644
+520 −0
Original line number Diff line number Diff line 
/*

 * timbuart.c timberdale FPGA UART driver

 * Copyright (c) 2009 Intel Corporation

 *

 * 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.

 *

 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.

 */



/* Supports:

 * Timberdale FPGA UART

 */



#include <linux/pci.h>

#include <linux/interrupt.h>

#include <linux/serial_core.h>

#include <linux/kernel.h>

#include <linux/platform_device.h>

#include <linux/ioport.h>



#include "timbuart.h"



struct timbuart_port {

	struct uart_port	port;

	struct tasklet_struct	tasklet;

	int			usedma;

	u8			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, u8 isr, u8 *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 */

	u8 ier = ioread8(port->membase + TIMBUART_IER) & ~RXFLAGS;

	iowrite8(ier, port->membase + TIMBUART_IER);

}



static void timbuart_stop_tx(struct uart_port *port)

{

	/* spinlock held by upper layer, disable TX interrupt */

	u8 ier = ioread8(port->membase + TIMBUART_IER) & ~TXBAE;

	iowrite8(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 void timbuart_flush_buffer(struct uart_port *port)

{

	u8 ctl = ioread8(port->membase + TIMBUART_CTRL) | TIMBUART_CTRL_FLSHTX;



	iowrite8(ctl, port->membase + TIMBUART_CTRL);

	iowrite8(TXBF, port->membase + TIMBUART_ISR);

}



static void timbuart_rx_chars(struct uart_port *port)

{

	struct tty_struct *tty = port->info->port.tty;



	while (ioread8(port->membase + TIMBUART_ISR) & RXDP) {

		u8 ch = ioread8(port->membase + TIMBUART_RXFIFO);

		port->icount.rx++;

		tty_insert_flip_char(tty, ch, TTY_NORMAL);

	}



	spin_unlock(&port->lock);

	tty_flip_buffer_push(port->info->port.tty);

	spin_lock(&port->lock);



	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->info->xmit;



	while (!(ioread8(port->membase + TIMBUART_ISR) & TXBF) &&

		!uart_circ_empty(xmit)) {

		iowrite8(xmit->buf[xmit->tail],

			port->membase + TIMBUART_TXFIFO);

		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);

		port->icount.tx++;

	}



	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, u8 isr, u8 *ier)

{

	struct timbuart_port *uart =

		container_of(port, struct timbuart_port, port);

	struct circ_buf *xmit = &port->info->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 */

		iowrite8(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__);

}



void timbuart_handle_rx_port(struct uart_port *port, u8 isr, u8 *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 */

		iowrite8(RXFLAGS, port->membase + TIMBUART_ISR);

	}



	/* always have the RX interrupts enabled */

	*ier |= RXBAF | RXBF | RXTT;



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

}



void timbuart_tasklet(unsigned long arg)

{

	struct timbuart_port *uart = (struct timbuart_port *)arg;

	u8 isr, ier = 0;



	spin_lock(&uart->port.lock);



	isr = ioread8(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);



	iowrite8(ier, uart->port.membase + TIMBUART_IER);



	spin_unlock(&uart->port.lock);

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

}



static unsigned int timbuart_tx_empty(struct uart_port *port)

{

	u8 isr = ioread8(port->membase + TIMBUART_ISR);



	return (isr & TXBAE) ? TIOCSER_TEMT : 0;

}



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(TIMBUART_CTRL_RTS, port->membase + TIMBUART_CTRL);

}



static void timbuart_mctrl_check(struct uart_port *port, u8 isr, u8 *ier)

{

	unsigned int cts;



	if (isr & CTS_DELTA) {

		/* ack */

		iowrite8(CTS_DELTA, port->membase + TIMBUART_ISR);

		cts = timbuart_get_mctrl(port);

		uart_handle_cts_change(port, cts & TIOCM_CTS);

		wake_up_interruptible(&port->info->delta_msr_wait);

	}



	*ier |= CTS_DELTA;

}



static void timbuart_enable_ms(struct uart_port *port)

{

	/* N/A */

}



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);

	iowrite8(0xff, port->membase + TIMBUART_ISR);

	/* Enable all but TX interrupts */

	iowrite8(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);

	iowrite8(0, port->membase + TIMBUART_IER);

}



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,

	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) {

		printk(KERN_ALERT "timbuart: Unsupported baud rate\n");

	} else {

		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 = ioread8(uart->port.membase + TIMBUART_IER);



		/* disable interrupts, the tasklet enables them again */

		iowrite8(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 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,

	.enable_ms = timbuart_enable_ms,

	.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;

	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;



	uart->port.irq = platform_get_irq(dev, 0);

	if (uart->port.irq < 0) {

		err = -EINVAL;

		goto err_register;

	}



	tasklet_init(&uart->tasklet, timbuart_tasklet, (unsigned long)uart);



	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",

		.owner	= THIS_MODULE,

	},

	.probe		= timbuart_probe,

	.remove		= timbuart_remove,

};



/*--------------------------------------------------------------------------*/



static int __init timbuart_init(void)

{

	return platform_driver_register(&timbuart_platform_driver);

}



static void __exit timbuart_exit(void)

{

	platform_driver_unregister(&timbuart_platform_driver);

}



module_init(timbuart_init);

module_exit(timbuart_exit);



MODULE_DESCRIPTION("Timberdale UART driver");

MODULE_LICENSE("GPL v2");

MODULE_ALIAS("platform:timb-uart");

drivers/serial/timbuart.h

0 → 100644
+58 −0
Original line number Diff line number Diff line 
/*

 * timbuart.c timberdale FPGA GPIO driver

 * Copyright (c) 2009 Intel Corporation

 *

 * 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.

 *

 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.

 */



/* Supports:

 * Timberdale FPGA UART

 */



#ifndef _TIMBUART_H

#define _TIMBUART_H



#define TIMBUART_FIFO_SIZE	2048



#define TIMBUART_RXFIFO		0x08

#define TIMBUART_TXFIFO		0x0c

#define TIMBUART_IER		0x10

#define TIMBUART_IPR		0x14

#define TIMBUART_ISR		0x18

#define TIMBUART_CTRL		0x1c

#define TIMBUART_BAUDRATE	0x20



#define TIMBUART_CTRL_RTS	0x01

#define TIMBUART_CTRL_CTS	0x02

#define TIMBUART_CTRL_FLSHTX	0x40

#define TIMBUART_CTRL_FLSHRX	0x80



#define TXBF		0x01

#define TXBAE		0x02

#define CTS_DELTA	0x04

#define RXDP		0x08

#define RXBAF		0x10

#define RXBF		0x20

#define RXTT		0x40

#define RXBNAE		0x80

#define TXBE		0x100



#define RXFLAGS (RXDP | RXBAF | RXBF | RXTT | RXBNAE)

#define TXFLAGS (TXBF | TXBAE)



#define TIMBUART_MAJOR 204

#define TIMBUART_MINOR 192



#endif /* _TIMBUART_H */

include/linux/serial_core.h

+3 −0
Original line number Diff line number Diff line
@@ -168,6 +168,9 @@ 
/* MAX3100 */

#define PORT_MAX3100    86



/* Timberdale UART */

#define PORT_TIMBUART	87



#ifdef __KERNEL__



#include <linux/compiler.h>