// SPDX-License-Identifier: GPL-2.0+
|
/*
|
* altera_jtaguart.c -- Altera JTAG UART driver
|
*
|
* Based on mcf.c -- Freescale ColdFire UART driver
|
*
|
* (C) Copyright 2003-2007, Greg Ungerer <gerg@snapgear.com>
|
* (C) Copyright 2008, Thomas Chou <thomas@wytron.com.tw>
|
* (C) Copyright 2010, Tobias Klauser <tklauser@distanz.ch>
|
*/
|
|
#include <linux/kernel.h>
|
#include <linux/init.h>
|
#include <linux/interrupt.h>
|
#include <linux/module.h>
|
#include <linux/console.h>
|
#include <linux/of.h>
|
#include <linux/tty.h>
|
#include <linux/tty_flip.h>
|
#include <linux/serial.h>
|
#include <linux/serial_core.h>
|
#include <linux/platform_device.h>
|
#include <linux/io.h>
|
#include <linux/altera_jtaguart.h>
|
|
#define DRV_NAME "altera_jtaguart"
|
|
/*
|
* Altera JTAG UART register definitions according to the Altera JTAG UART
|
* datasheet: http://www.altera.com/literature/hb/nios2/n2cpu_nii51009.pdf
|
*/
|
|
#define ALTERA_JTAGUART_SIZE 8
|
|
#define ALTERA_JTAGUART_DATA_REG 0
|
|
#define ALTERA_JTAGUART_DATA_DATA_MSK 0x000000FF
|
#define ALTERA_JTAGUART_DATA_RVALID_MSK 0x00008000
|
#define ALTERA_JTAGUART_DATA_RAVAIL_MSK 0xFFFF0000
|
#define ALTERA_JTAGUART_DATA_RAVAIL_OFF 16
|
|
#define ALTERA_JTAGUART_CONTROL_REG 4
|
|
#define ALTERA_JTAGUART_CONTROL_RE_MSK 0x00000001
|
#define ALTERA_JTAGUART_CONTROL_WE_MSK 0x00000002
|
#define ALTERA_JTAGUART_CONTROL_RI_MSK 0x00000100
|
#define ALTERA_JTAGUART_CONTROL_RI_OFF 8
|
#define ALTERA_JTAGUART_CONTROL_WI_MSK 0x00000200
|
#define ALTERA_JTAGUART_CONTROL_AC_MSK 0x00000400
|
#define ALTERA_JTAGUART_CONTROL_WSPACE_MSK 0xFFFF0000
|
#define ALTERA_JTAGUART_CONTROL_WSPACE_OFF 16
|
|
/*
|
* Local per-uart structure.
|
*/
|
struct altera_jtaguart {
|
struct uart_port port;
|
unsigned int sigs; /* Local copy of line sigs */
|
unsigned long imr; /* Local IMR mirror */
|
};
|
|
static unsigned int altera_jtaguart_tx_empty(struct uart_port *port)
|
{
|
return (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) &
|
ALTERA_JTAGUART_CONTROL_WSPACE_MSK) ? TIOCSER_TEMT : 0;
|
}
|
|
static unsigned int altera_jtaguart_get_mctrl(struct uart_port *port)
|
{
|
return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
|
}
|
|
static void altera_jtaguart_set_mctrl(struct uart_port *port, unsigned int sigs)
|
{
|
}
|
|
static void altera_jtaguart_start_tx(struct uart_port *port)
|
{
|
struct altera_jtaguart *pp =
|
container_of(port, struct altera_jtaguart, port);
|
|
pp->imr |= ALTERA_JTAGUART_CONTROL_WE_MSK;
|
writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
|
}
|
|
static void altera_jtaguart_stop_tx(struct uart_port *port)
|
{
|
struct altera_jtaguart *pp =
|
container_of(port, struct altera_jtaguart, port);
|
|
pp->imr &= ~ALTERA_JTAGUART_CONTROL_WE_MSK;
|
writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
|
}
|
|
static void altera_jtaguart_stop_rx(struct uart_port *port)
|
{
|
struct altera_jtaguart *pp =
|
container_of(port, struct altera_jtaguart, port);
|
|
pp->imr &= ~ALTERA_JTAGUART_CONTROL_RE_MSK;
|
writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
|
}
|
|
static void altera_jtaguart_break_ctl(struct uart_port *port, int break_state)
|
{
|
}
|
|
static void altera_jtaguart_set_termios(struct uart_port *port,
|
struct ktermios *termios,
|
struct ktermios *old)
|
{
|
/* Just copy the old termios settings back */
|
if (old)
|
tty_termios_copy_hw(termios, old);
|
}
|
|
static void altera_jtaguart_rx_chars(struct altera_jtaguart *pp)
|
{
|
struct uart_port *port = &pp->port;
|
unsigned char ch, flag;
|
unsigned long status;
|
|
while ((status = readl(port->membase + ALTERA_JTAGUART_DATA_REG)) &
|
ALTERA_JTAGUART_DATA_RVALID_MSK) {
|
ch = status & ALTERA_JTAGUART_DATA_DATA_MSK;
|
flag = TTY_NORMAL;
|
port->icount.rx++;
|
|
if (uart_handle_sysrq_char(port, ch))
|
continue;
|
uart_insert_char(port, 0, 0, ch, flag);
|
}
|
|
spin_unlock(&port->lock);
|
tty_flip_buffer_push(&port->state->port);
|
spin_lock(&port->lock);
|
}
|
|
static void altera_jtaguart_tx_chars(struct altera_jtaguart *pp)
|
{
|
struct uart_port *port = &pp->port;
|
struct circ_buf *xmit = &port->state->xmit;
|
unsigned int pending, count;
|
|
if (port->x_char) {
|
/* Send special char - probably flow control */
|
writel(port->x_char, port->membase + ALTERA_JTAGUART_DATA_REG);
|
port->x_char = 0;
|
port->icount.tx++;
|
return;
|
}
|
|
pending = uart_circ_chars_pending(xmit);
|
if (pending > 0) {
|
count = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) &
|
ALTERA_JTAGUART_CONTROL_WSPACE_MSK) >>
|
ALTERA_JTAGUART_CONTROL_WSPACE_OFF;
|
if (count > pending)
|
count = pending;
|
if (count > 0) {
|
pending -= count;
|
while (count--) {
|
writel(xmit->buf[xmit->tail],
|
port->membase + ALTERA_JTAGUART_DATA_REG);
|
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
|
port->icount.tx++;
|
}
|
if (pending < WAKEUP_CHARS)
|
uart_write_wakeup(port);
|
}
|
}
|
|
if (pending == 0) {
|
pp->imr &= ~ALTERA_JTAGUART_CONTROL_WE_MSK;
|
writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
|
}
|
}
|
|
static irqreturn_t altera_jtaguart_interrupt(int irq, void *data)
|
{
|
struct uart_port *port = data;
|
struct altera_jtaguart *pp =
|
container_of(port, struct altera_jtaguart, port);
|
unsigned int isr;
|
|
isr = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) >>
|
ALTERA_JTAGUART_CONTROL_RI_OFF) & pp->imr;
|
|
spin_lock(&port->lock);
|
|
if (isr & ALTERA_JTAGUART_CONTROL_RE_MSK)
|
altera_jtaguart_rx_chars(pp);
|
if (isr & ALTERA_JTAGUART_CONTROL_WE_MSK)
|
altera_jtaguart_tx_chars(pp);
|
|
spin_unlock(&port->lock);
|
|
return IRQ_RETVAL(isr);
|
}
|
|
static void altera_jtaguart_config_port(struct uart_port *port, int flags)
|
{
|
port->type = PORT_ALTERA_JTAGUART;
|
|
/* Clear mask, so no surprise interrupts. */
|
writel(0, port->membase + ALTERA_JTAGUART_CONTROL_REG);
|
}
|
|
static int altera_jtaguart_startup(struct uart_port *port)
|
{
|
struct altera_jtaguart *pp =
|
container_of(port, struct altera_jtaguart, port);
|
unsigned long flags;
|
int ret;
|
|
ret = request_irq(port->irq, altera_jtaguart_interrupt, 0,
|
DRV_NAME, port);
|
if (ret) {
|
pr_err(DRV_NAME ": unable to attach Altera JTAG UART %d "
|
"interrupt vector=%d\n", port->line, port->irq);
|
return ret;
|
}
|
|
spin_lock_irqsave(&port->lock, flags);
|
|
/* Enable RX interrupts now */
|
pp->imr = ALTERA_JTAGUART_CONTROL_RE_MSK;
|
writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
|
|
spin_unlock_irqrestore(&port->lock, flags);
|
|
return 0;
|
}
|
|
static void altera_jtaguart_shutdown(struct uart_port *port)
|
{
|
struct altera_jtaguart *pp =
|
container_of(port, struct altera_jtaguart, port);
|
unsigned long flags;
|
|
spin_lock_irqsave(&port->lock, flags);
|
|
/* Disable all interrupts now */
|
pp->imr = 0;
|
writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
|
|
spin_unlock_irqrestore(&port->lock, flags);
|
|
free_irq(port->irq, port);
|
}
|
|
static const char *altera_jtaguart_type(struct uart_port *port)
|
{
|
return (port->type == PORT_ALTERA_JTAGUART) ? "Altera JTAG UART" : NULL;
|
}
|
|
static int altera_jtaguart_request_port(struct uart_port *port)
|
{
|
/* UARTs always present */
|
return 0;
|
}
|
|
static void altera_jtaguart_release_port(struct uart_port *port)
|
{
|
/* Nothing to release... */
|
}
|
|
static int altera_jtaguart_verify_port(struct uart_port *port,
|
struct serial_struct *ser)
|
{
|
if (ser->type != PORT_UNKNOWN && ser->type != PORT_ALTERA_JTAGUART)
|
return -EINVAL;
|
return 0;
|
}
|
|
/*
|
* Define the basic serial functions we support.
|
*/
|
static const struct uart_ops altera_jtaguart_ops = {
|
.tx_empty = altera_jtaguart_tx_empty,
|
.get_mctrl = altera_jtaguart_get_mctrl,
|
.set_mctrl = altera_jtaguart_set_mctrl,
|
.start_tx = altera_jtaguart_start_tx,
|
.stop_tx = altera_jtaguart_stop_tx,
|
.stop_rx = altera_jtaguart_stop_rx,
|
.break_ctl = altera_jtaguart_break_ctl,
|
.startup = altera_jtaguart_startup,
|
.shutdown = altera_jtaguart_shutdown,
|
.set_termios = altera_jtaguart_set_termios,
|
.type = altera_jtaguart_type,
|
.request_port = altera_jtaguart_request_port,
|
.release_port = altera_jtaguart_release_port,
|
.config_port = altera_jtaguart_config_port,
|
.verify_port = altera_jtaguart_verify_port,
|
};
|
|
#define ALTERA_JTAGUART_MAXPORTS 1
|
static struct altera_jtaguart altera_jtaguart_ports[ALTERA_JTAGUART_MAXPORTS];
|
|
#if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE)
|
|
#if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE_BYPASS)
|
static void altera_jtaguart_console_putc(struct uart_port *port, int c)
|
{
|
unsigned long status;
|
unsigned long flags;
|
|
spin_lock_irqsave(&port->lock, flags);
|
while (((status = readl(port->membase + ALTERA_JTAGUART_CONTROL_REG)) &
|
ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) {
|
if ((status & ALTERA_JTAGUART_CONTROL_AC_MSK) == 0) {
|
spin_unlock_irqrestore(&port->lock, flags);
|
return; /* no connection activity */
|
}
|
spin_unlock_irqrestore(&port->lock, flags);
|
cpu_relax();
|
spin_lock_irqsave(&port->lock, flags);
|
}
|
writel(c, port->membase + ALTERA_JTAGUART_DATA_REG);
|
spin_unlock_irqrestore(&port->lock, flags);
|
}
|
#else
|
static void altera_jtaguart_console_putc(struct uart_port *port, int c)
|
{
|
unsigned long flags;
|
|
spin_lock_irqsave(&port->lock, flags);
|
while ((readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) &
|
ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) {
|
spin_unlock_irqrestore(&port->lock, flags);
|
cpu_relax();
|
spin_lock_irqsave(&port->lock, flags);
|
}
|
writel(c, port->membase + ALTERA_JTAGUART_DATA_REG);
|
spin_unlock_irqrestore(&port->lock, flags);
|
}
|
#endif
|
|
static void altera_jtaguart_console_write(struct console *co, const char *s,
|
unsigned int count)
|
{
|
struct uart_port *port = &(altera_jtaguart_ports + co->index)->port;
|
|
uart_console_write(port, s, count, altera_jtaguart_console_putc);
|
}
|
|
static int __init altera_jtaguart_console_setup(struct console *co,
|
char *options)
|
{
|
struct uart_port *port;
|
|
if (co->index < 0 || co->index >= ALTERA_JTAGUART_MAXPORTS)
|
return -EINVAL;
|
port = &altera_jtaguart_ports[co->index].port;
|
if (port->membase == NULL)
|
return -ENODEV;
|
return 0;
|
}
|
|
static struct uart_driver altera_jtaguart_driver;
|
|
static struct console altera_jtaguart_console = {
|
.name = "ttyJ",
|
.write = altera_jtaguart_console_write,
|
.device = uart_console_device,
|
.setup = altera_jtaguart_console_setup,
|
.flags = CON_PRINTBUFFER,
|
.index = -1,
|
.data = &altera_jtaguart_driver,
|
};
|
|
static int __init altera_jtaguart_console_init(void)
|
{
|
register_console(&altera_jtaguart_console);
|
return 0;
|
}
|
|
console_initcall(altera_jtaguart_console_init);
|
|
#define ALTERA_JTAGUART_CONSOLE (&altera_jtaguart_console)
|
|
static void altera_jtaguart_earlycon_write(struct console *co, const char *s,
|
unsigned int count)
|
{
|
struct earlycon_device *dev = co->data;
|
|
uart_console_write(&dev->port, s, count, altera_jtaguart_console_putc);
|
}
|
|
static int __init altera_jtaguart_earlycon_setup(struct earlycon_device *dev,
|
const char *options)
|
{
|
if (!dev->port.membase)
|
return -ENODEV;
|
|
dev->con->write = altera_jtaguart_earlycon_write;
|
return 0;
|
}
|
|
OF_EARLYCON_DECLARE(juart, "altr,juart-1.0", altera_jtaguart_earlycon_setup);
|
|
#else
|
|
#define ALTERA_JTAGUART_CONSOLE NULL
|
|
#endif /* CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE */
|
|
static struct uart_driver altera_jtaguart_driver = {
|
.owner = THIS_MODULE,
|
.driver_name = "altera_jtaguart",
|
.dev_name = "ttyJ",
|
.major = ALTERA_JTAGUART_MAJOR,
|
.minor = ALTERA_JTAGUART_MINOR,
|
.nr = ALTERA_JTAGUART_MAXPORTS,
|
.cons = ALTERA_JTAGUART_CONSOLE,
|
};
|
|
static int altera_jtaguart_probe(struct platform_device *pdev)
|
{
|
struct altera_jtaguart_platform_uart *platp =
|
dev_get_platdata(&pdev->dev);
|
struct uart_port *port;
|
struct resource *res_irq, *res_mem;
|
int i = pdev->id;
|
|
/* -1 emphasizes that the platform must have one port, no .N suffix */
|
if (i == -1)
|
i = 0;
|
|
if (i >= ALTERA_JTAGUART_MAXPORTS)
|
return -EINVAL;
|
|
port = &altera_jtaguart_ports[i].port;
|
|
res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
if (res_mem)
|
port->mapbase = res_mem->start;
|
else if (platp)
|
port->mapbase = platp->mapbase;
|
else
|
return -ENODEV;
|
|
res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
|
if (res_irq)
|
port->irq = res_irq->start;
|
else if (platp)
|
port->irq = platp->irq;
|
else
|
return -ENODEV;
|
|
port->membase = ioremap(port->mapbase, ALTERA_JTAGUART_SIZE);
|
if (!port->membase)
|
return -ENOMEM;
|
|
port->line = i;
|
port->type = PORT_ALTERA_JTAGUART;
|
port->iotype = SERIAL_IO_MEM;
|
port->ops = &altera_jtaguart_ops;
|
port->flags = UPF_BOOT_AUTOCONF;
|
port->dev = &pdev->dev;
|
|
uart_add_one_port(&altera_jtaguart_driver, port);
|
|
return 0;
|
}
|
|
static int altera_jtaguart_remove(struct platform_device *pdev)
|
{
|
struct uart_port *port;
|
int i = pdev->id;
|
|
if (i == -1)
|
i = 0;
|
|
port = &altera_jtaguart_ports[i].port;
|
uart_remove_one_port(&altera_jtaguart_driver, port);
|
iounmap(port->membase);
|
|
return 0;
|
}
|
|
#ifdef CONFIG_OF
|
static const struct of_device_id altera_jtaguart_match[] = {
|
{ .compatible = "ALTR,juart-1.0", },
|
{ .compatible = "altr,juart-1.0", },
|
{},
|
};
|
MODULE_DEVICE_TABLE(of, altera_jtaguart_match);
|
#endif /* CONFIG_OF */
|
|
static struct platform_driver altera_jtaguart_platform_driver = {
|
.probe = altera_jtaguart_probe,
|
.remove = altera_jtaguart_remove,
|
.driver = {
|
.name = DRV_NAME,
|
.of_match_table = of_match_ptr(altera_jtaguart_match),
|
},
|
};
|
|
static int __init altera_jtaguart_init(void)
|
{
|
int rc;
|
|
rc = uart_register_driver(&altera_jtaguart_driver);
|
if (rc)
|
return rc;
|
rc = platform_driver_register(&altera_jtaguart_platform_driver);
|
if (rc)
|
uart_unregister_driver(&altera_jtaguart_driver);
|
return rc;
|
}
|
|
static void __exit altera_jtaguart_exit(void)
|
{
|
platform_driver_unregister(&altera_jtaguart_platform_driver);
|
uart_unregister_driver(&altera_jtaguart_driver);
|
}
|
|
module_init(altera_jtaguart_init);
|
module_exit(altera_jtaguart_exit);
|
|
MODULE_DESCRIPTION("Altera JTAG UART driver");
|
MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
|
MODULE_LICENSE("GPL");
|
MODULE_ALIAS("platform:" DRV_NAME);
|
