- 根目录:
- drivers
- tty
- serial
- timbuart.c
/*
* 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/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);
}
spin_unlock(&port->lock);
tty_flip_buffer_push(tport);
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->state->xmit;
while (!(ioread32(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, 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(unsigned long arg)
{
struct timbuart_port *uart = (struct timbuart_port *)arg;
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);
}
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)
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 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_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,
};
module_platform_driver(timbuart_platform_driver);
MODULE_DESCRIPTION("Timberdale UART driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:timb-uart");