// 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 <[email protected]>
* (C) Copyright 2008, Thomas Chou <[email protected]>
* (C) Copyright 2010, Tobias Klauser <[email protected]>
*/
#include <linux/bitfield.h>
#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: https://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
static unsigned int altera_jtaguart_tx_space(struct uart_port *port, u32 *ctlp)
{
u32 ctl = readl(port->membase + ALTERA_JTAGUART_CONTROL_REG);
if (ctlp)
*ctlp = ctl;
return FIELD_GET(ALTERA_JTAGUART_CONTROL_WSPACE_MSK, ctl);
}
static unsigned int altera_jtaguart_tx_empty(struct uart_port *port)
{
return altera_jtaguart_tx_space(port, NULL) ? 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)
{
port->read_status_mask |= ALTERA_JTAGUART_CONTROL_WE_MSK;
writel(port->read_status_mask,
port->membase + ALTERA_JTAGUART_CONTROL_REG);
}
static void altera_jtaguart_stop_tx(struct uart_port *port)
{
port->read_status_mask &= ~ALTERA_JTAGUART_CONTROL_WE_MSK;
writel(port->read_status_mask,
port->membase + ALTERA_JTAGUART_CONTROL_REG);
}
static void altera_jtaguart_stop_rx(struct uart_port *port)
{
port->read_status_mask &= ~ALTERA_JTAGUART_CONTROL_RE_MSK;
writel(port->read_status_mask,
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,
const 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 uart_port *port)
{
u32 status;
u8 ch;
while ((status = readl(port->membase + ALTERA_JTAGUART_DATA_REG)) &
ALTERA_JTAGUART_DATA_RVALID_MSK) {
ch = status & ALTERA_JTAGUART_DATA_DATA_MSK;
port->icount.rx++;
if (uart_handle_sysrq_char(port, ch))
continue;
uart_insert_char(port, 0, 0, ch, TTY_NORMAL);
}
tty_flip_buffer_push(&port->state->port);
}
static void altera_jtaguart_tx_chars(struct uart_port *port)
{
unsigned int count;
u8 ch;
count = altera_jtaguart_tx_space(port, NULL);
uart_port_tx_limited(port, ch, count,
true,
writel(ch, port->membase + ALTERA_JTAGUART_DATA_REG),
({}));
}
static irqreturn_t altera_jtaguart_interrupt(int irq, void *data)
{
struct uart_port *port = data;
unsigned int isr;
isr = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) >>
ALTERA_JTAGUART_CONTROL_RI_OFF) & port->read_status_mask;
uart_port_lock(port);
if (isr & ALTERA_JTAGUART_CONTROL_RE_MSK)
altera_jtaguart_rx_chars(port);
if (isr & ALTERA_JTAGUART_CONTROL_WE_MSK)
altera_jtaguart_tx_chars(port);
uart_port_unlock(port);
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)
{
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;
}
uart_port_lock_irqsave(port, &flags);
/* Enable RX interrupts now */
port->read_status_mask = ALTERA_JTAGUART_CONTROL_RE_MSK;
writel(port->read_status_mask,
port->membase + ALTERA_JTAGUART_CONTROL_REG);
uart_port_unlock_irqrestore(port, flags);
return 0;
}
static void altera_jtaguart_shutdown(struct uart_port *port)
{
unsigned long flags;
uart_port_lock_irqsave(port, &flags);
/* Disable all interrupts now */
port->read_status_mask = 0;
writel(port->read_status_mask,
port->membase + ALTERA_JTAGUART_CONTROL_REG);
uart_port_unlock_irqrestore(port, 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 uart_port 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, unsigned char c)
{
unsigned long flags;
u32 status;
uart_port_lock_irqsave(port, &flags);
while (!altera_jtaguart_tx_space(port, &status)) {
uart_port_unlock_irqrestore(port, flags);
if ((status & ALTERA_JTAGUART_CONTROL_AC_MSK) == 0) {
return; /* no connection activity */
}
cpu_relax();
uart_port_lock_irqsave(port, &flags);
}
writel(c, port->membase + ALTERA_JTAGUART_DATA_REG);
uart_port_unlock_irqrestore(port, flags);
}
#else
static void altera_jtaguart_console_putc(struct uart_port *port, unsigned char c)
{
unsigned long flags;
uart_port_lock_irqsave(port, &flags);
while (!altera_jtaguart_tx_space(port, NULL)) {
uart_port_unlock_irqrestore(port, flags);
cpu_relax();
uart_port_lock_irqsave(port, &flags);
}
writel(c, port->membase + ALTERA_JTAGUART_DATA_REG);
uart_port_unlock_irqrestore(port, 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];
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];
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_mem;
int i = pdev->id;
int irq;
/* -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];
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;
irq = platform_get_irq_optional(pdev, 0);
if (irq < 0 && irq != -ENXIO)
return irq;
if (irq > 0)
port->irq = irq;
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 void 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];
uart_remove_one_port(&altera_jtaguart_driver, port);
iounmap(port->membase);
}
#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_new = 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 <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);
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