mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 19:00:25 +00:00
![Alan Cox](/assets/img/avatar_default.png)
This is used by various drivers not just serial and can be extracted as commonality Signed-off-by: Alan Cox <alan@linux.intel.com>
526 lines
13 KiB
C
526 lines
13 KiB
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/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;
|
|
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 void timbuart_flush_buffer(struct uart_port *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_struct *tty = port->state->port.tty;
|
|
|
|
while (ioread32(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->state->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->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__);
|
|
}
|
|
|
|
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__);
|
|
}
|
|
|
|
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_tx_empty(struct uart_port *port)
|
|
{
|
|
u32 isr = ioread32(port->membase + TIMBUART_ISR);
|
|
|
|
return (isr & TXBE) ? 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, 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_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);
|
|
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,
|
|
.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");
|
|
|