- 根目录:
- drivers
- tty
- serial
- tilegx.c
/*
* Copyright 2013 Tilera Corporation. All Rights Reserved.
*
* 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, version 2.
*
* 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, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*
* TILEGx UART driver.
*/
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/serial_core.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <gxio/common.h>
#include <gxio/iorpc_globals.h>
#include <gxio/iorpc_uart.h>
#include <gxio/kiorpc.h>
#include <hv/drv_uart_intf.h>
/*
* Use device name ttyS, major 4, minor 64-65.
* This is the usual serial port name, 8250 conventional range.
*/
#define TILEGX_UART_MAJOR TTY_MAJOR
#define TILEGX_UART_MINOR 64
#define TILEGX_UART_NAME "ttyS"
#define DRIVER_NAME_STRING "TILEGx_Serial"
#define TILEGX_UART_REF_CLK 125000000; /* REF_CLK is always 125 MHz. */
struct tile_uart_port {
/* UART port. */
struct uart_port uart;
/* GXIO device context. */
gxio_uart_context_t context;
/* UART access mutex. */
struct mutex mutex;
/* CPU receiving interrupts. */
int irq_cpu;
};
static struct tile_uart_port tile_uart_ports[TILEGX_UART_NR];
static struct uart_driver tilegx_uart_driver;
/*
* Read UART rx fifo, and insert the chars into tty buffer.
*/
static void receive_chars(struct tile_uart_port *tile_uart,
struct tty_struct *tty)
{
int i;
char c;
UART_FIFO_COUNT_t count;
gxio_uart_context_t *context = &tile_uart->context;
struct tty_port *port = tty->port;
count.word = gxio_uart_read(context, UART_FIFO_COUNT);
for (i = 0; i < count.rfifo_count; i++) {
c = (char)gxio_uart_read(context, UART_RECEIVE_DATA);
tty_insert_flip_char(port, c, TTY_NORMAL);
}
}
/*
* Drain the Rx FIFO, called by interrupt handler.
*/
static void handle_receive(struct tile_uart_port *tile_uart)
{
struct tty_port *port = &tile_uart->uart.state->port;
struct tty_struct *tty = tty_port_tty_get(port);
gxio_uart_context_t *context = &tile_uart->context;
if (!tty)
return;
/* First read UART rx fifo. */
receive_chars(tile_uart, tty);
/* Reset RFIFO_WE interrupt. */
gxio_uart_write(context, UART_INTERRUPT_STATUS,
UART_INTERRUPT_MASK__RFIFO_WE_MASK);
/* Final read, if any chars comes between the first read and
* the interrupt reset.
*/
receive_chars(tile_uart, tty);
spin_unlock(&tile_uart->uart.lock);
tty_flip_buffer_push(port);
spin_lock(&tile_uart->uart.lock);
tty_kref_put(tty);
}
/*
* Push one char to UART Write FIFO.
* Return 0 on success, -1 if write filo is full.
*/
static int tilegx_putchar(gxio_uart_context_t *context, char c)
{
UART_FLAG_t flag;
flag.word = gxio_uart_read(context, UART_FLAG);
if (flag.wfifo_full)
return -1;
gxio_uart_write(context, UART_TRANSMIT_DATA, (unsigned long)c);
return 0;
}
/*
* Send chars to UART Write FIFO; called by interrupt handler.
*/
static void handle_transmit(struct tile_uart_port *tile_uart)
{
unsigned char ch;
struct uart_port *port;
struct circ_buf *xmit;
gxio_uart_context_t *context = &tile_uart->context;
/* First reset WFIFO_RE interrupt. */
gxio_uart_write(context, UART_INTERRUPT_STATUS,
UART_INTERRUPT_MASK__WFIFO_RE_MASK);
port = &tile_uart->uart;
xmit = &port->state->xmit;
if (port->x_char) {
if (tilegx_putchar(context, port->x_char))
return;
port->x_char = 0;
port->icount.tx++;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(port))
return;
while (!uart_circ_empty(xmit)) {
ch = xmit->buf[xmit->tail];
if (tilegx_putchar(context, ch))
break;
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
}
/* Reset WFIFO_RE interrupt. */
gxio_uart_write(context, UART_INTERRUPT_STATUS,
UART_INTERRUPT_MASK__WFIFO_RE_MASK);
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
}
/*
* UART Interrupt handler.
*/
static irqreturn_t tilegx_interrupt(int irq, void *dev_id)
{
unsigned long flags;
UART_INTERRUPT_STATUS_t intr_stat;
struct tile_uart_port *tile_uart;
gxio_uart_context_t *context;
struct uart_port *port = dev_id;
irqreturn_t ret = IRQ_NONE;
spin_lock_irqsave(&port->lock, flags);
tile_uart = container_of(port, struct tile_uart_port, uart);
context = &tile_uart->context;
intr_stat.word = gxio_uart_read(context, UART_INTERRUPT_STATUS);
if (intr_stat.rfifo_we) {
handle_receive(tile_uart);
ret = IRQ_HANDLED;
}
if (intr_stat.wfifo_re) {
handle_transmit(tile_uart);
ret = IRQ_HANDLED;
}
spin_unlock_irqrestore(&port->lock, flags);
return ret;
}
/*
* Return TIOCSER_TEMT when transmitter FIFO is empty.
*/
static u_int tilegx_tx_empty(struct uart_port *port)
{
int ret;
UART_FLAG_t flag;
struct tile_uart_port *tile_uart;
gxio_uart_context_t *context;
tile_uart = container_of(port, struct tile_uart_port, uart);
if (!mutex_trylock(&tile_uart->mutex))
return 0;
context = &tile_uart->context;
flag.word = gxio_uart_read(context, UART_FLAG);
ret = (flag.wfifo_empty) ? TIOCSER_TEMT : 0;
mutex_unlock(&tile_uart->mutex);
return ret;
}
/*
* Set state of the modem control output lines.
*/
static void tilegx_set_mctrl(struct uart_port *port, u_int mctrl)
{
/* N/A */
}
/*
* Get state of the modem control input lines.
*/
static u_int tilegx_get_mctrl(struct uart_port *port)
{
return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
}
/*
* Stop transmitting.
*/
static void tilegx_stop_tx(struct uart_port *port)
{
/* N/A */
}
/*
* Start transmitting.
*/
static void tilegx_start_tx(struct uart_port *port)
{
unsigned char ch;
struct circ_buf *xmit;
struct tile_uart_port *tile_uart;
gxio_uart_context_t *context;
tile_uart = container_of(port, struct tile_uart_port, uart);
if (!mutex_trylock(&tile_uart->mutex))
return;
context = &tile_uart->context;
xmit = &port->state->xmit;
if (port->x_char) {
if (tilegx_putchar(context, port->x_char))
return;
port->x_char = 0;
port->icount.tx++;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
mutex_unlock(&tile_uart->mutex);
return;
}
while (!uart_circ_empty(xmit)) {
ch = xmit->buf[xmit->tail];
if (tilegx_putchar(context, ch))
break;
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
}
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
mutex_unlock(&tile_uart->mutex);
}
/*
* Stop receiving - port is in process of being closed.
*/
static void tilegx_stop_rx(struct uart_port *port)
{
int err;
struct tile_uart_port *tile_uart;
gxio_uart_context_t *context;
int cpu;
tile_uart = container_of(port, struct tile_uart_port, uart);
if (!mutex_trylock(&tile_uart->mutex))
return;
context = &tile_uart->context;
cpu = tile_uart->irq_cpu;
err = gxio_uart_cfg_interrupt(context, cpu_x(cpu), cpu_y(cpu),
KERNEL_PL, -1);
mutex_unlock(&tile_uart->mutex);
}
/*
* Control the transmission of a break signal.
*/
static void tilegx_break_ctl(struct uart_port *port, int break_state)
{
/* N/A */
}
/*
* Perform initialization and enable port for reception.
*/
static int tilegx_startup(struct uart_port *port)
{
struct tile_uart_port *tile_uart;
gxio_uart_context_t *context;
int ret = 0;
int cpu = raw_smp_processor_id(); /* pick an arbitrary cpu */
tile_uart = container_of(port, struct tile_uart_port, uart);
if (mutex_lock_interruptible(&tile_uart->mutex))
return -EBUSY;
context = &tile_uart->context;
/* Now open the hypervisor device if we haven't already. */
if (context->fd < 0) {
UART_INTERRUPT_MASK_t intr_mask;
/* Initialize UART device. */
ret = gxio_uart_init(context, port->line);
if (ret) {
ret = -ENXIO;
goto err;
}
/* Create our IRQs. */
port->irq = irq_alloc_hwirq(-1);
if (!port->irq)
goto err_uart_dest;
tile_irq_activate(port->irq, TILE_IRQ_PERCPU);
/* Register our IRQs. */
ret = request_irq(port->irq, tilegx_interrupt, 0,
tilegx_uart_driver.driver_name, port);
if (ret)
goto err_dest_irq;
/* Request that the hardware start sending us interrupts. */
tile_uart->irq_cpu = cpu;
ret = gxio_uart_cfg_interrupt(context, cpu_x(cpu), cpu_y(cpu),
KERNEL_PL, port->irq);
if (ret)
goto err_free_irq;
/* Enable UART Tx/Rx Interrupt. */
intr_mask.word = gxio_uart_read(context, UART_INTERRUPT_MASK);
intr_mask.wfifo_re = 0;
intr_mask.rfifo_we = 0;
gxio_uart_write(context, UART_INTERRUPT_MASK, intr_mask.word);
/* Reset the Tx/Rx interrupt in case it's set. */
gxio_uart_write(context, UART_INTERRUPT_STATUS,
UART_INTERRUPT_MASK__WFIFO_RE_MASK |
UART_INTERRUPT_MASK__RFIFO_WE_MASK);
}
mutex_unlock(&tile_uart->mutex);
return ret;
err_free_irq:
free_irq(port->irq, port);
err_dest_irq:
irq_free_hwirq(port->irq);
err_uart_dest:
gxio_uart_destroy(context);
ret = -ENXIO;
err:
mutex_unlock(&tile_uart->mutex);
return ret;
}
/*
* Release kernel resources if it is the last close, disable the port,
* free IRQ and close the port.
*/
static void tilegx_shutdown(struct uart_port *port)
{
int err;
UART_INTERRUPT_MASK_t intr_mask;
struct tile_uart_port *tile_uart;
gxio_uart_context_t *context;
int cpu;
tile_uart = container_of(port, struct tile_uart_port, uart);
if (mutex_lock_interruptible(&tile_uart->mutex))
return;
context = &tile_uart->context;
/* Disable UART Tx/Rx Interrupt. */
intr_mask.word = gxio_uart_read(context, UART_INTERRUPT_MASK);
intr_mask.wfifo_re = 1;
intr_mask.rfifo_we = 1;
gxio_uart_write(context, UART_INTERRUPT_MASK, intr_mask.word);
/* Request that the hardware stop sending us interrupts. */
cpu = tile_uart->irq_cpu;
err = gxio_uart_cfg_interrupt(context, cpu_x(cpu), cpu_y(cpu),
KERNEL_PL, -1);
if (port->irq > 0) {
free_irq(port->irq, port);
irq_free_hwirq(port->irq);
port->irq = 0;
}
gxio_uart_destroy(context);
mutex_unlock(&tile_uart->mutex);
}
/*
* Flush the buffer.
*/
static void tilegx_flush_buffer(struct uart_port *port)
{
/* N/A */
}
/*
* Change the port parameters.
*/
static void tilegx_set_termios(struct uart_port *port,
struct ktermios *termios, struct ktermios *old)
{
int err;
UART_DIVISOR_t divisor;
UART_TYPE_t type;
unsigned int baud;
struct tile_uart_port *tile_uart;
gxio_uart_context_t *context;
tile_uart = container_of(port, struct tile_uart_port, uart);
if (!mutex_trylock(&tile_uart->mutex))
return;
context = &tile_uart->context;
/* Open the hypervisor device if we haven't already. */
if (context->fd < 0) {
err = gxio_uart_init(context, port->line);
if (err) {
mutex_unlock(&tile_uart->mutex);
return;
}
}
divisor.word = gxio_uart_read(context, UART_DIVISOR);
type.word = gxio_uart_read(context, UART_TYPE);
/* Divisor. */
baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
divisor.divisor = uart_get_divisor(port, baud);
/* Byte size. */
if ((termios->c_cflag & CSIZE) == CS7)
type.dbits = UART_TYPE__DBITS_VAL_SEVEN_DBITS;
else
type.dbits = UART_TYPE__DBITS_VAL_EIGHT_DBITS;
/* Parity. */
if (termios->c_cflag & PARENB) {
/* Mark or Space parity. */
if (termios->c_cflag & CMSPAR)
if (termios->c_cflag & PARODD)
type.ptype = UART_TYPE__PTYPE_VAL_MARK;
else
type.ptype = UART_TYPE__PTYPE_VAL_SPACE;
else if (termios->c_cflag & PARODD)
type.ptype = UART_TYPE__PTYPE_VAL_ODD;
else
type.ptype = UART_TYPE__PTYPE_VAL_EVEN;
} else
type.ptype = UART_TYPE__PTYPE_VAL_NONE;
/* Stop bits. */
if (termios->c_cflag & CSTOPB)
type.sbits = UART_TYPE__SBITS_VAL_TWO_SBITS;
else
type.sbits = UART_TYPE__SBITS_VAL_ONE_SBITS;
/* Set the uart paramters. */
gxio_uart_write(context, UART_DIVISOR, divisor.word);
gxio_uart_write(context, UART_TYPE, type.word);
mutex_unlock(&tile_uart->mutex);
}
/*
* Return string describing the specified port.
*/
static const char *tilegx_type(struct uart_port *port)
{
return port->type == PORT_TILEGX ? DRIVER_NAME_STRING : NULL;
}
/*
* Release the resources being used by 'port'.
*/
static void tilegx_release_port(struct uart_port *port)
{
/* Nothing to release. */
}
/*
* Request the resources being used by 'port'.
*/
static int tilegx_request_port(struct uart_port *port)
{
/* Always present. */
return 0;
}
/*
* Configure/autoconfigure the port.
*/
static void tilegx_config_port(struct uart_port *port, int flags)
{
if (flags & UART_CONFIG_TYPE)
port->type = PORT_TILEGX;
}
/*
* Verify the new serial_struct (for TIOCSSERIAL).
*/
static int tilegx_verify_port(struct uart_port *port,
struct serial_struct *ser)
{
if ((ser->type != PORT_UNKNOWN) && (ser->type != PORT_TILEGX))
return -EINVAL;
return 0;
}
#ifdef CONFIG_CONSOLE_POLL
/*
* Console polling routines for writing and reading from the uart while
* in an interrupt or debug context.
*/
static int tilegx_poll_get_char(struct uart_port *port)
{
UART_FIFO_COUNT_t count;
gxio_uart_context_t *context;
struct tile_uart_port *tile_uart;
tile_uart = container_of(port, struct tile_uart_port, uart);
context = &tile_uart->context;
count.word = gxio_uart_read(context, UART_FIFO_COUNT);
if (count.rfifo_count == 0)
return NO_POLL_CHAR;
return (char)gxio_uart_read(context, UART_RECEIVE_DATA);
}
static void tilegx_poll_put_char(struct uart_port *port, unsigned char c)
{
gxio_uart_context_t *context;
struct tile_uart_port *tile_uart;
tile_uart = container_of(port, struct tile_uart_port, uart);
context = &tile_uart->context;
gxio_uart_write(context, UART_TRANSMIT_DATA, (unsigned long)c);
}
#endif /* CONFIG_CONSOLE_POLL */
static const struct uart_ops tilegx_ops = {
.tx_empty = tilegx_tx_empty,
.set_mctrl = tilegx_set_mctrl,
.get_mctrl = tilegx_get_mctrl,
.stop_tx = tilegx_stop_tx,
.start_tx = tilegx_start_tx,
.stop_rx = tilegx_stop_rx,
.break_ctl = tilegx_break_ctl,
.startup = tilegx_startup,
.shutdown = tilegx_shutdown,
.flush_buffer = tilegx_flush_buffer,
.set_termios = tilegx_set_termios,
.type = tilegx_type,
.release_port = tilegx_release_port,
.request_port = tilegx_request_port,
.config_port = tilegx_config_port,
.verify_port = tilegx_verify_port,
#ifdef CONFIG_CONSOLE_POLL
.poll_get_char = tilegx_poll_get_char,
.poll_put_char = tilegx_poll_put_char,
#endif
};
static void tilegx_init_ports(void)
{
int i;
struct uart_port *port;
for (i = 0; i < TILEGX_UART_NR; i++) {
port = &tile_uart_ports[i].uart;
port->ops = &tilegx_ops;
port->line = i;
port->type = PORT_TILEGX;
port->uartclk = TILEGX_UART_REF_CLK;
port->flags = UPF_BOOT_AUTOCONF;
tile_uart_ports[i].context.fd = -1;
mutex_init(&tile_uart_ports[i].mutex);
}
}
static struct uart_driver tilegx_uart_driver = {
.owner = THIS_MODULE,
.driver_name = DRIVER_NAME_STRING,
.dev_name = TILEGX_UART_NAME,
.major = TILEGX_UART_MAJOR,
.minor = TILEGX_UART_MINOR,
.nr = TILEGX_UART_NR,
};
static int __init tilegx_init(void)
{
int i;
int ret;
struct tty_driver *tty_drv;
ret = uart_register_driver(&tilegx_uart_driver);
if (ret)
return ret;
tty_drv = tilegx_uart_driver.tty_driver;
tty_drv->init_termios.c_cflag = B115200 | CS8 | CREAD | HUPCL | CLOCAL;
tty_drv->init_termios.c_ispeed = 115200;
tty_drv->init_termios.c_ospeed = 115200;
tilegx_init_ports();
for (i = 0; i < TILEGX_UART_NR; i++) {
struct uart_port *port = &tile_uart_ports[i].uart;
ret = uart_add_one_port(&tilegx_uart_driver, port);
}
return 0;
}
static void __exit tilegx_exit(void)
{
int i;
struct uart_port *port;
for (i = 0; i < TILEGX_UART_NR; i++) {
port = &tile_uart_ports[i].uart;
uart_remove_one_port(&tilegx_uart_driver, port);
}
uart_unregister_driver(&tilegx_uart_driver);
}
module_init(tilegx_init);
module_exit(tilegx_exit);
MODULE_AUTHOR("Tilera Corporation");
MODULE_DESCRIPTION("TILEGx serial port driver");
MODULE_LICENSE("GPL");