// SPDX-License-Identifier: GPL-2.0+
/*
* altera_uart.c -- Altera 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/kernel.h>
#include <linux/init.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/console.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/of.h>
#include <linux/io.h>
#include <linux/altera_uart.h>
#define DRV_NAME "altera_uart"
#define SERIAL_ALTERA_MAJOR 204
#define SERIAL_ALTERA_MINOR 213
/*
* Altera UART register definitions according to the Nios UART datasheet:
* http://www.altera.com/literature/ds/ds_nios_uart.pdf
*/
#define ALTERA_UART_SIZE 32
#define ALTERA_UART_RXDATA_REG 0
#define ALTERA_UART_TXDATA_REG 4
#define ALTERA_UART_STATUS_REG 8
#define ALTERA_UART_CONTROL_REG 12
#define ALTERA_UART_DIVISOR_REG 16
#define ALTERA_UART_EOP_REG 20
#define ALTERA_UART_STATUS_PE_MSK 0x0001 /* parity error */
#define ALTERA_UART_STATUS_FE_MSK 0x0002 /* framing error */
#define ALTERA_UART_STATUS_BRK_MSK 0x0004 /* break */
#define ALTERA_UART_STATUS_ROE_MSK 0x0008 /* RX overrun error */
#define ALTERA_UART_STATUS_TOE_MSK 0x0010 /* TX overrun error */
#define ALTERA_UART_STATUS_TMT_MSK 0x0020 /* TX shift register state */
#define ALTERA_UART_STATUS_TRDY_MSK 0x0040 /* TX ready */
#define ALTERA_UART_STATUS_RRDY_MSK 0x0080 /* RX ready */
#define ALTERA_UART_STATUS_E_MSK 0x0100 /* exception condition */
#define ALTERA_UART_STATUS_DCTS_MSK 0x0400 /* CTS logic-level change */
#define ALTERA_UART_STATUS_CTS_MSK 0x0800 /* CTS logic state */
#define ALTERA_UART_STATUS_EOP_MSK 0x1000 /* EOP written/read */
/* Enable interrupt on... */
#define ALTERA_UART_CONTROL_PE_MSK 0x0001 /* ...parity error */
#define ALTERA_UART_CONTROL_FE_MSK 0x0002 /* ...framing error */
#define ALTERA_UART_CONTROL_BRK_MSK 0x0004 /* ...break */
#define ALTERA_UART_CONTROL_ROE_MSK 0x0008 /* ...RX overrun */
#define ALTERA_UART_CONTROL_TOE_MSK 0x0010 /* ...TX overrun */
#define ALTERA_UART_CONTROL_TMT_MSK 0x0020 /* ...TX shift register empty */
#define ALTERA_UART_CONTROL_TRDY_MSK 0x0040 /* ...TX ready */
#define ALTERA_UART_CONTROL_RRDY_MSK 0x0080 /* ...RX ready */
#define ALTERA_UART_CONTROL_E_MSK 0x0100 /* ...exception*/
#define ALTERA_UART_CONTROL_TRBK_MSK 0x0200 /* TX break */
#define ALTERA_UART_CONTROL_DCTS_MSK 0x0400 /* Interrupt on CTS change */
#define ALTERA_UART_CONTROL_RTS_MSK 0x0800 /* RTS signal */
#define ALTERA_UART_CONTROL_EOP_MSK 0x1000 /* Interrupt on EOP */
/*
* Local per-uart structure.
*/
struct altera_uart {
struct uart_port port;
struct timer_list tmr;
unsigned int sigs; /* Local copy of line sigs */
unsigned short imr; /* Local IMR mirror */
};
static u32 altera_uart_readl(struct uart_port *port, int reg)
{
return readl(port->membase + (reg << port->regshift));
}
static void altera_uart_writel(struct uart_port *port, u32 dat, int reg)
{
writel(dat, port->membase + (reg << port->regshift));
}
static unsigned int altera_uart_tx_empty(struct uart_port *port)
{
return (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
ALTERA_UART_STATUS_TMT_MSK) ? TIOCSER_TEMT : 0;
}
static unsigned int altera_uart_get_mctrl(struct uart_port *port)
{
struct altera_uart *pp = container_of(port, struct altera_uart, port);
unsigned int sigs;
sigs = (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
ALTERA_UART_STATUS_CTS_MSK) ? TIOCM_CTS : 0;
sigs |= (pp->sigs & TIOCM_RTS);
return sigs;
}
static void altera_uart_update_ctrl_reg(struct altera_uart *pp)
{
unsigned short imr = pp->imr;
/*
* If the device doesn't have an irq, ensure that the irq bits are
* masked out to keep the irq line inactive.
*/
if (!pp->port.irq)
imr &= ALTERA_UART_CONTROL_TRBK_MSK | ALTERA_UART_CONTROL_RTS_MSK;
altera_uart_writel(&pp->port, imr, ALTERA_UART_CONTROL_REG);
}
static void altera_uart_set_mctrl(struct uart_port *port, unsigned int sigs)
{
struct altera_uart *pp = container_of(port, struct altera_uart, port);
pp->sigs = sigs;
if (sigs & TIOCM_RTS)
pp->imr |= ALTERA_UART_CONTROL_RTS_MSK;
else
pp->imr &= ~ALTERA_UART_CONTROL_RTS_MSK;
altera_uart_update_ctrl_reg(pp);
}
static void altera_uart_start_tx(struct uart_port *port)
{
struct altera_uart *pp = container_of(port, struct altera_uart, port);
pp->imr |= ALTERA_UART_CONTROL_TRDY_MSK;
altera_uart_update_ctrl_reg(pp);
}
static void altera_uart_stop_tx(struct uart_port *port)
{
struct altera_uart *pp = container_of(port, struct altera_uart, port);
pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
altera_uart_update_ctrl_reg(pp);
}
static void altera_uart_stop_rx(struct uart_port *port)
{
struct altera_uart *pp = container_of(port, struct altera_uart, port);
pp->imr &= ~ALTERA_UART_CONTROL_RRDY_MSK;
altera_uart_update_ctrl_reg(pp);
}
static void altera_uart_break_ctl(struct uart_port *port, int break_state)
{
struct altera_uart *pp = container_of(port, struct altera_uart, port);
unsigned long flags;
uart_port_lock_irqsave(port, &flags);
if (break_state == -1)
pp->imr |= ALTERA_UART_CONTROL_TRBK_MSK;
else
pp->imr &= ~ALTERA_UART_CONTROL_TRBK_MSK;
altera_uart_update_ctrl_reg(pp);
uart_port_unlock_irqrestore(port, flags);
}
static void altera_uart_set_termios(struct uart_port *port,
struct ktermios *termios,
const struct ktermios *old)
{
unsigned long flags;
unsigned int baud, baudclk;
baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
baudclk = port->uartclk / baud;
if (old)
tty_termios_copy_hw(termios, old);
tty_termios_encode_baud_rate(termios, baud, baud);
uart_port_lock_irqsave(port, &flags);
uart_update_timeout(port, termios->c_cflag, baud);
altera_uart_writel(port, baudclk, ALTERA_UART_DIVISOR_REG);
uart_port_unlock_irqrestore(port, flags);
/*
* FIXME: port->read_status_mask and port->ignore_status_mask
* need to be initialized based on termios settings for
* INPCK, IGNBRK, IGNPAR, PARMRK, BRKINT
*/
}
static void altera_uart_rx_chars(struct uart_port *port)
{
unsigned short status;
u8 ch, flag;
while ((status = altera_uart_readl(port, ALTERA_UART_STATUS_REG)) &
ALTERA_UART_STATUS_RRDY_MSK) {
ch = altera_uart_readl(port, ALTERA_UART_RXDATA_REG);
flag = TTY_NORMAL;
port->icount.rx++;
if (status & ALTERA_UART_STATUS_E_MSK) {
altera_uart_writel(port, status,
ALTERA_UART_STATUS_REG);
if (status & ALTERA_UART_STATUS_BRK_MSK) {
port->icount.brk++;
if (uart_handle_break(port))
continue;
} else if (status & ALTERA_UART_STATUS_PE_MSK) {
port->icount.parity++;
} else if (status & ALTERA_UART_STATUS_ROE_MSK) {
port->icount.overrun++;
} else if (status & ALTERA_UART_STATUS_FE_MSK) {
port->icount.frame++;
}
status &= port->read_status_mask;
if (status & ALTERA_UART_STATUS_BRK_MSK)
flag = TTY_BREAK;
else if (status & ALTERA_UART_STATUS_PE_MSK)
flag = TTY_PARITY;
else if (status & ALTERA_UART_STATUS_FE_MSK)
flag = TTY_FRAME;
}
if (uart_handle_sysrq_char(port, ch))
continue;
uart_insert_char(port, status, ALTERA_UART_STATUS_ROE_MSK, ch,
flag);
}
tty_flip_buffer_push(&port->state->port);
}
static void altera_uart_tx_chars(struct uart_port *port)
{
u8 ch;
uart_port_tx(port, ch,
altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
ALTERA_UART_STATUS_TRDY_MSK,
altera_uart_writel(port, ch, ALTERA_UART_TXDATA_REG));
}
static irqreturn_t altera_uart_interrupt(int irq, void *data)
{
struct uart_port *port = data;
struct altera_uart *pp = container_of(port, struct altera_uart, port);
unsigned long flags;
unsigned int isr;
isr = altera_uart_readl(port, ALTERA_UART_STATUS_REG) & pp->imr;
uart_port_lock_irqsave(port, &flags);
if (isr & ALTERA_UART_STATUS_RRDY_MSK)
altera_uart_rx_chars(port);
if (isr & ALTERA_UART_STATUS_TRDY_MSK)
altera_uart_tx_chars(port);
uart_port_unlock_irqrestore(port, flags);
return IRQ_RETVAL(isr);
}
static void altera_uart_timer(struct timer_list *t)
{
struct altera_uart *pp = from_timer(pp, t, tmr);
struct uart_port *port = &pp->port;
altera_uart_interrupt(0, port);
mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
}
static void altera_uart_config_port(struct uart_port *port, int flags)
{
port->type = PORT_ALTERA_UART;
/* Clear mask, so no surprise interrupts. */
altera_uart_writel(port, 0, ALTERA_UART_CONTROL_REG);
/* Clear status register */
altera_uart_writel(port, 0, ALTERA_UART_STATUS_REG);
}
static int altera_uart_startup(struct uart_port *port)
{
struct altera_uart *pp = container_of(port, struct altera_uart, port);
unsigned long flags;
if (!port->irq) {
timer_setup(&pp->tmr, altera_uart_timer, 0);
mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
} else {
int ret;
ret = request_irq(port->irq, altera_uart_interrupt, 0,
dev_name(port->dev), port);
if (ret) {
pr_err(DRV_NAME ": unable to attach Altera UART %d "
"interrupt vector=%d\n", port->line, port->irq);
return ret;
}
}
uart_port_lock_irqsave(port, &flags);
/* Enable RX interrupts now */
pp->imr = ALTERA_UART_CONTROL_RRDY_MSK;
altera_uart_update_ctrl_reg(pp);
uart_port_unlock_irqrestore(port, flags);
return 0;
}
static void altera_uart_shutdown(struct uart_port *port)
{
struct altera_uart *pp = container_of(port, struct altera_uart, port);
unsigned long flags;
uart_port_lock_irqsave(port, &flags);
/* Disable all interrupts now */
pp->imr = 0;
altera_uart_update_ctrl_reg(pp);
uart_port_unlock_irqrestore(port, flags);
if (port->irq)
free_irq(port->irq, port);
else
del_timer_sync(&pp->tmr);
}
static const char *altera_uart_type(struct uart_port *port)
{
return (port->type == PORT_ALTERA_UART) ? "Altera UART" : NULL;
}
static int altera_uart_request_port(struct uart_port *port)
{
/* UARTs always present */
return 0;
}
static void altera_uart_release_port(struct uart_port *port)
{
/* Nothing to release... */
}
static int altera_uart_verify_port(struct uart_port *port,
struct serial_struct *ser)
{
if ((ser->type != PORT_UNKNOWN) && (ser->type != PORT_ALTERA_UART))
return -EINVAL;
return 0;
}
#ifdef CONFIG_CONSOLE_POLL
static int altera_uart_poll_get_char(struct uart_port *port)
{
while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
ALTERA_UART_STATUS_RRDY_MSK))
cpu_relax();
return altera_uart_readl(port, ALTERA_UART_RXDATA_REG);
}
static void altera_uart_poll_put_char(struct uart_port *port, unsigned char c)
{
while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
ALTERA_UART_STATUS_TRDY_MSK))
cpu_relax();
altera_uart_writel(port, c, ALTERA_UART_TXDATA_REG);
}
#endif
/*
* Define the basic serial functions we support.
*/
static const struct uart_ops altera_uart_ops = {
.tx_empty = altera_uart_tx_empty,
.get_mctrl = altera_uart_get_mctrl,
.set_mctrl = altera_uart_set_mctrl,
.start_tx = altera_uart_start_tx,
.stop_tx = altera_uart_stop_tx,
.stop_rx = altera_uart_stop_rx,
.break_ctl = altera_uart_break_ctl,
.startup = altera_uart_startup,
.shutdown = altera_uart_shutdown,
.set_termios = altera_uart_set_termios,
.type = altera_uart_type,
.request_port = altera_uart_request_port,
.release_port = altera_uart_release_port,
.config_port = altera_uart_config_port,
.verify_port = altera_uart_verify_port,
#ifdef CONFIG_CONSOLE_POLL
.poll_get_char = altera_uart_poll_get_char,
.poll_put_char = altera_uart_poll_put_char,
#endif
};
static struct altera_uart altera_uart_ports[CONFIG_SERIAL_ALTERA_UART_MAXPORTS];
#if defined(CONFIG_SERIAL_ALTERA_UART_CONSOLE)
static void altera_uart_console_putc(struct uart_port *port, unsigned char c)
{
while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
ALTERA_UART_STATUS_TRDY_MSK))
cpu_relax();
altera_uart_writel(port, c, ALTERA_UART_TXDATA_REG);
}
static void altera_uart_console_write(struct console *co, const char *s,
unsigned int count)
{
struct uart_port *port = &(altera_uart_ports + co->index)->port;
uart_console_write(port, s, count, altera_uart_console_putc);
}
static int __init altera_uart_console_setup(struct console *co, char *options)
{
struct uart_port *port;
int baud = CONFIG_SERIAL_ALTERA_UART_BAUDRATE;
int bits = 8;
int parity = 'n';
int flow = 'n';
if (co->index < 0 || co->index >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
return -EINVAL;
port = &altera_uart_ports[co->index].port;
if (!port->membase)
return -ENODEV;
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(port, co, baud, parity, bits, flow);
}
static struct uart_driver altera_uart_driver;
static struct console altera_uart_console = {
.name = "ttyAL",
.write = altera_uart_console_write,
.device = uart_console_device,
.setup = altera_uart_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &altera_uart_driver,
};
static int __init altera_uart_console_init(void)
{
register_console(&altera_uart_console);
return 0;
}
console_initcall(altera_uart_console_init);
#define ALTERA_UART_CONSOLE (&altera_uart_console)
static void altera_uart_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_uart_console_putc);
}
static int __init altera_uart_earlycon_setup(struct earlycon_device *dev,
const char *options)
{
struct uart_port *port = &dev->port;
if (!port->membase)
return -ENODEV;
/* Enable RX interrupts now */
altera_uart_writel(port, ALTERA_UART_CONTROL_RRDY_MSK,
ALTERA_UART_CONTROL_REG);
if (dev->baud) {
unsigned int baudclk = port->uartclk / dev->baud;
altera_uart_writel(port, baudclk, ALTERA_UART_DIVISOR_REG);
}
dev->con->write = altera_uart_earlycon_write;
return 0;
}
OF_EARLYCON_DECLARE(uart, "altr,uart-1.0", altera_uart_earlycon_setup);
#else
#define ALTERA_UART_CONSOLE NULL
#endif /* CONFIG_SERIAL_ALTERA_UART_CONSOLE */
/*
* Define the altera_uart UART driver structure.
*/
static struct uart_driver altera_uart_driver = {
.owner = THIS_MODULE,
.driver_name = DRV_NAME,
.dev_name = "ttyAL",
.major = SERIAL_ALTERA_MAJOR,
.minor = SERIAL_ALTERA_MINOR,
.nr = CONFIG_SERIAL_ALTERA_UART_MAXPORTS,
.cons = ALTERA_UART_CONSOLE,
};
static int altera_uart_probe(struct platform_device *pdev)
{
struct altera_uart_platform_uart *platp = dev_get_platdata(&pdev->dev);
struct uart_port *port;
struct resource *res_mem;
int i = pdev->id;
int ret;
/* if id is -1 scan for a free id and use that one */
if (i == -1) {
for (i = 0; i < CONFIG_SERIAL_ALTERA_UART_MAXPORTS; i++)
if (altera_uart_ports[i].port.mapbase == 0)
break;
}
if (i < 0 || i >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
return -EINVAL;
port = &altera_uart_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 -EINVAL;
ret = platform_get_irq_optional(pdev, 0);
if (ret < 0 && ret != -ENXIO)
return ret;
if (ret > 0)
port->irq = ret;
else if (platp)
port->irq = platp->irq;
/* Check platform data first so we can override device node data */
if (platp)
port->uartclk = platp->uartclk;
else {
ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency",
&port->uartclk);
if (ret)
return ret;
}
port->membase = ioremap(port->mapbase, ALTERA_UART_SIZE);
if (!port->membase)
return -ENOMEM;
if (platp)
port->regshift = platp->bus_shift;
else
port->regshift = 0;
port->line = i;
port->type = PORT_ALTERA_UART;
port->iotype = SERIAL_IO_MEM;
port->ops = &altera_uart_ops;
port->flags = UPF_BOOT_AUTOCONF;
port->dev = &pdev->dev;
platform_set_drvdata(pdev, port);
uart_add_one_port(&altera_uart_driver, port);
return 0;
}
static void altera_uart_remove(struct platform_device *pdev)
{
struct uart_port *port = platform_get_drvdata(pdev);
if (port) {
uart_remove_one_port(&altera_uart_driver, port);
port->mapbase = 0;
iounmap(port->membase);
}
}
#ifdef CONFIG_OF
static const struct of_device_id altera_uart_match[] = {
{ .compatible = "ALTR,uart-1.0", },
{ .compatible = "altr,uart-1.0", },
{},
};
MODULE_DEVICE_TABLE(of, altera_uart_match);
#endif /* CONFIG_OF */
static struct platform_driver altera_uart_platform_driver = {
.probe = altera_uart_probe,
.remove_new = altera_uart_remove,
.driver = {
.name = DRV_NAME,
.of_match_table = of_match_ptr(altera_uart_match),
},
};
static int __init altera_uart_init(void)
{
int rc;
rc = uart_register_driver(&altera_uart_driver);
if (rc)
return rc;
rc = platform_driver_register(&altera_uart_platform_driver);
if (rc)
uart_unregister_driver(&altera_uart_driver);
return rc;
}
static void __exit altera_uart_exit(void)
{
platform_driver_unregister(&altera_uart_platform_driver);
uart_unregister_driver(&altera_uart_driver);
}
module_init(altera_uart_init);
module_exit(altera_uart_exit);
MODULE_DESCRIPTION("Altera UART driver");
MODULE_AUTHOR("Thomas Chou <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);
MODULE_ALIAS_CHARDEV_MAJOR(SERIAL_ALTERA_MAJOR);
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