1 // SPDX-License-Identifier: GPL-2.0+
3 * altera_uart.c -- Altera UART driver
5 * Based on mcf.c -- Freescale ColdFire UART driver
7 * (C) Copyright 2003-2007, Greg Ungerer <gerg@snapgear.com>
8 * (C) Copyright 2008, Thomas Chou <thomas@wytron.com.tw>
9 * (C) Copyright 2010, Tobias Klauser <tklauser@distanz.ch>
12 #include <linux/kernel.h>
13 #include <linux/init.h>
14 #include <linux/timer.h>
15 #include <linux/interrupt.h>
16 #include <linux/module.h>
17 #include <linux/console.h>
18 #include <linux/tty.h>
19 #include <linux/tty_flip.h>
20 #include <linux/serial.h>
21 #include <linux/serial_core.h>
22 #include <linux/platform_device.h>
25 #include <linux/altera_uart.h>
27 #define DRV_NAME "altera_uart"
28 #define SERIAL_ALTERA_MAJOR 204
29 #define SERIAL_ALTERA_MINOR 213
32 * Altera UART register definitions according to the Nios UART datasheet:
33 * http://www.altera.com/literature/ds/ds_nios_uart.pdf
36 #define ALTERA_UART_SIZE 32
38 #define ALTERA_UART_RXDATA_REG 0
39 #define ALTERA_UART_TXDATA_REG 4
40 #define ALTERA_UART_STATUS_REG 8
41 #define ALTERA_UART_CONTROL_REG 12
42 #define ALTERA_UART_DIVISOR_REG 16
43 #define ALTERA_UART_EOP_REG 20
45 #define ALTERA_UART_STATUS_PE_MSK 0x0001 /* parity error */
46 #define ALTERA_UART_STATUS_FE_MSK 0x0002 /* framing error */
47 #define ALTERA_UART_STATUS_BRK_MSK 0x0004 /* break */
48 #define ALTERA_UART_STATUS_ROE_MSK 0x0008 /* RX overrun error */
49 #define ALTERA_UART_STATUS_TOE_MSK 0x0010 /* TX overrun error */
50 #define ALTERA_UART_STATUS_TMT_MSK 0x0020 /* TX shift register state */
51 #define ALTERA_UART_STATUS_TRDY_MSK 0x0040 /* TX ready */
52 #define ALTERA_UART_STATUS_RRDY_MSK 0x0080 /* RX ready */
53 #define ALTERA_UART_STATUS_E_MSK 0x0100 /* exception condition */
54 #define ALTERA_UART_STATUS_DCTS_MSK 0x0400 /* CTS logic-level change */
55 #define ALTERA_UART_STATUS_CTS_MSK 0x0800 /* CTS logic state */
56 #define ALTERA_UART_STATUS_EOP_MSK 0x1000 /* EOP written/read */
58 /* Enable interrupt on... */
59 #define ALTERA_UART_CONTROL_PE_MSK 0x0001 /* ...parity error */
60 #define ALTERA_UART_CONTROL_FE_MSK 0x0002 /* ...framing error */
61 #define ALTERA_UART_CONTROL_BRK_MSK 0x0004 /* ...break */
62 #define ALTERA_UART_CONTROL_ROE_MSK 0x0008 /* ...RX overrun */
63 #define ALTERA_UART_CONTROL_TOE_MSK 0x0010 /* ...TX overrun */
64 #define ALTERA_UART_CONTROL_TMT_MSK 0x0020 /* ...TX shift register empty */
65 #define ALTERA_UART_CONTROL_TRDY_MSK 0x0040 /* ...TX ready */
66 #define ALTERA_UART_CONTROL_RRDY_MSK 0x0080 /* ...RX ready */
67 #define ALTERA_UART_CONTROL_E_MSK 0x0100 /* ...exception*/
69 #define ALTERA_UART_CONTROL_TRBK_MSK 0x0200 /* TX break */
70 #define ALTERA_UART_CONTROL_DCTS_MSK 0x0400 /* Interrupt on CTS change */
71 #define ALTERA_UART_CONTROL_RTS_MSK 0x0800 /* RTS signal */
72 #define ALTERA_UART_CONTROL_EOP_MSK 0x1000 /* Interrupt on EOP */
75 * Local per-uart structure.
78 struct uart_port port;
79 struct timer_list tmr;
80 unsigned int sigs; /* Local copy of line sigs */
81 unsigned short imr; /* Local IMR mirror */
84 static u32 altera_uart_readl(struct uart_port *port, int reg)
86 return readl(port->membase + (reg << port->regshift));
89 static void altera_uart_writel(struct uart_port *port, u32 dat, int reg)
91 writel(dat, port->membase + (reg << port->regshift));
94 static unsigned int altera_uart_tx_empty(struct uart_port *port)
96 return (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
97 ALTERA_UART_STATUS_TMT_MSK) ? TIOCSER_TEMT : 0;
100 static unsigned int altera_uart_get_mctrl(struct uart_port *port)
102 struct altera_uart *pp = container_of(port, struct altera_uart, port);
105 sigs = (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
106 ALTERA_UART_STATUS_CTS_MSK) ? TIOCM_CTS : 0;
107 sigs |= (pp->sigs & TIOCM_RTS);
112 static void altera_uart_update_ctrl_reg(struct altera_uart *pp)
114 unsigned short imr = pp->imr;
117 * If the device doesn't have an irq, ensure that the irq bits are
118 * masked out to keep the irq line inactive.
121 imr &= ALTERA_UART_CONTROL_TRBK_MSK | ALTERA_UART_CONTROL_RTS_MSK;
123 altera_uart_writel(&pp->port, imr, ALTERA_UART_CONTROL_REG);
126 static void altera_uart_set_mctrl(struct uart_port *port, unsigned int sigs)
128 struct altera_uart *pp = container_of(port, struct altera_uart, port);
131 if (sigs & TIOCM_RTS)
132 pp->imr |= ALTERA_UART_CONTROL_RTS_MSK;
134 pp->imr &= ~ALTERA_UART_CONTROL_RTS_MSK;
135 altera_uart_update_ctrl_reg(pp);
138 static void altera_uart_start_tx(struct uart_port *port)
140 struct altera_uart *pp = container_of(port, struct altera_uart, port);
142 pp->imr |= ALTERA_UART_CONTROL_TRDY_MSK;
143 altera_uart_update_ctrl_reg(pp);
146 static void altera_uart_stop_tx(struct uart_port *port)
148 struct altera_uart *pp = container_of(port, struct altera_uart, port);
150 pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
151 altera_uart_update_ctrl_reg(pp);
154 static void altera_uart_stop_rx(struct uart_port *port)
156 struct altera_uart *pp = container_of(port, struct altera_uart, port);
158 pp->imr &= ~ALTERA_UART_CONTROL_RRDY_MSK;
159 altera_uart_update_ctrl_reg(pp);
162 static void altera_uart_break_ctl(struct uart_port *port, int break_state)
164 struct altera_uart *pp = container_of(port, struct altera_uart, port);
167 spin_lock_irqsave(&port->lock, flags);
168 if (break_state == -1)
169 pp->imr |= ALTERA_UART_CONTROL_TRBK_MSK;
171 pp->imr &= ~ALTERA_UART_CONTROL_TRBK_MSK;
172 altera_uart_update_ctrl_reg(pp);
173 spin_unlock_irqrestore(&port->lock, flags);
176 static void altera_uart_set_termios(struct uart_port *port,
177 struct ktermios *termios,
178 struct ktermios *old)
181 unsigned int baud, baudclk;
183 baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
184 baudclk = port->uartclk / baud;
187 tty_termios_copy_hw(termios, old);
188 tty_termios_encode_baud_rate(termios, baud, baud);
190 spin_lock_irqsave(&port->lock, flags);
191 uart_update_timeout(port, termios->c_cflag, baud);
192 altera_uart_writel(port, baudclk, ALTERA_UART_DIVISOR_REG);
193 spin_unlock_irqrestore(&port->lock, flags);
196 * FIXME: port->read_status_mask and port->ignore_status_mask
197 * need to be initialized based on termios settings for
198 * INPCK, IGNBRK, IGNPAR, PARMRK, BRKINT
202 static void altera_uart_rx_chars(struct uart_port *port)
204 unsigned char ch, flag;
205 unsigned short status;
207 while ((status = altera_uart_readl(port, ALTERA_UART_STATUS_REG)) &
208 ALTERA_UART_STATUS_RRDY_MSK) {
209 ch = altera_uart_readl(port, ALTERA_UART_RXDATA_REG);
213 if (status & ALTERA_UART_STATUS_E_MSK) {
214 altera_uart_writel(port, status,
215 ALTERA_UART_STATUS_REG);
217 if (status & ALTERA_UART_STATUS_BRK_MSK) {
219 if (uart_handle_break(port))
221 } else if (status & ALTERA_UART_STATUS_PE_MSK) {
222 port->icount.parity++;
223 } else if (status & ALTERA_UART_STATUS_ROE_MSK) {
224 port->icount.overrun++;
225 } else if (status & ALTERA_UART_STATUS_FE_MSK) {
226 port->icount.frame++;
229 status &= port->read_status_mask;
231 if (status & ALTERA_UART_STATUS_BRK_MSK)
233 else if (status & ALTERA_UART_STATUS_PE_MSK)
235 else if (status & ALTERA_UART_STATUS_FE_MSK)
239 if (uart_handle_sysrq_char(port, ch))
241 uart_insert_char(port, status, ALTERA_UART_STATUS_ROE_MSK, ch,
245 spin_unlock(&port->lock);
246 tty_flip_buffer_push(&port->state->port);
247 spin_lock(&port->lock);
250 static void altera_uart_tx_chars(struct uart_port *port)
252 struct circ_buf *xmit = &port->state->xmit;
255 /* Send special char - probably flow control */
256 altera_uart_writel(port, port->x_char, ALTERA_UART_TXDATA_REG);
262 while (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
263 ALTERA_UART_STATUS_TRDY_MSK) {
264 if (xmit->head == xmit->tail)
266 altera_uart_writel(port, xmit->buf[xmit->tail],
267 ALTERA_UART_TXDATA_REG);
268 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
272 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
273 uart_write_wakeup(port);
275 if (uart_circ_empty(xmit))
276 altera_uart_stop_tx(port);
279 static irqreturn_t altera_uart_interrupt(int irq, void *data)
281 struct uart_port *port = data;
282 struct altera_uart *pp = container_of(port, struct altera_uart, port);
286 isr = altera_uart_readl(port, ALTERA_UART_STATUS_REG) & pp->imr;
288 spin_lock_irqsave(&port->lock, flags);
289 if (isr & ALTERA_UART_STATUS_RRDY_MSK)
290 altera_uart_rx_chars(port);
291 if (isr & ALTERA_UART_STATUS_TRDY_MSK)
292 altera_uart_tx_chars(port);
293 spin_unlock_irqrestore(&port->lock, flags);
295 return IRQ_RETVAL(isr);
298 static void altera_uart_timer(struct timer_list *t)
300 struct altera_uart *pp = from_timer(pp, t, tmr);
301 struct uart_port *port = &pp->port;
303 altera_uart_interrupt(0, port);
304 mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
307 static void altera_uart_config_port(struct uart_port *port, int flags)
309 port->type = PORT_ALTERA_UART;
311 /* Clear mask, so no surprise interrupts. */
312 altera_uart_writel(port, 0, ALTERA_UART_CONTROL_REG);
313 /* Clear status register */
314 altera_uart_writel(port, 0, ALTERA_UART_STATUS_REG);
317 static int altera_uart_startup(struct uart_port *port)
319 struct altera_uart *pp = container_of(port, struct altera_uart, port);
323 timer_setup(&pp->tmr, altera_uart_timer, 0);
324 mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
328 ret = request_irq(port->irq, altera_uart_interrupt, 0,
331 pr_err(DRV_NAME ": unable to attach Altera UART %d "
332 "interrupt vector=%d\n", port->line, port->irq);
337 spin_lock_irqsave(&port->lock, flags);
339 /* Enable RX interrupts now */
340 pp->imr = ALTERA_UART_CONTROL_RRDY_MSK;
341 altera_uart_update_ctrl_reg(pp);
343 spin_unlock_irqrestore(&port->lock, flags);
348 static void altera_uart_shutdown(struct uart_port *port)
350 struct altera_uart *pp = container_of(port, struct altera_uart, port);
353 spin_lock_irqsave(&port->lock, flags);
355 /* Disable all interrupts now */
357 altera_uart_update_ctrl_reg(pp);
359 spin_unlock_irqrestore(&port->lock, flags);
362 free_irq(port->irq, port);
364 del_timer_sync(&pp->tmr);
367 static const char *altera_uart_type(struct uart_port *port)
369 return (port->type == PORT_ALTERA_UART) ? "Altera UART" : NULL;
372 static int altera_uart_request_port(struct uart_port *port)
374 /* UARTs always present */
378 static void altera_uart_release_port(struct uart_port *port)
380 /* Nothing to release... */
383 static int altera_uart_verify_port(struct uart_port *port,
384 struct serial_struct *ser)
386 if ((ser->type != PORT_UNKNOWN) && (ser->type != PORT_ALTERA_UART))
391 #ifdef CONFIG_CONSOLE_POLL
392 static int altera_uart_poll_get_char(struct uart_port *port)
394 while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
395 ALTERA_UART_STATUS_RRDY_MSK))
398 return altera_uart_readl(port, ALTERA_UART_RXDATA_REG);
401 static void altera_uart_poll_put_char(struct uart_port *port, unsigned char c)
403 while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
404 ALTERA_UART_STATUS_TRDY_MSK))
407 altera_uart_writel(port, c, ALTERA_UART_TXDATA_REG);
412 * Define the basic serial functions we support.
414 static const struct uart_ops altera_uart_ops = {
415 .tx_empty = altera_uart_tx_empty,
416 .get_mctrl = altera_uart_get_mctrl,
417 .set_mctrl = altera_uart_set_mctrl,
418 .start_tx = altera_uart_start_tx,
419 .stop_tx = altera_uart_stop_tx,
420 .stop_rx = altera_uart_stop_rx,
421 .break_ctl = altera_uart_break_ctl,
422 .startup = altera_uart_startup,
423 .shutdown = altera_uart_shutdown,
424 .set_termios = altera_uart_set_termios,
425 .type = altera_uart_type,
426 .request_port = altera_uart_request_port,
427 .release_port = altera_uart_release_port,
428 .config_port = altera_uart_config_port,
429 .verify_port = altera_uart_verify_port,
430 #ifdef CONFIG_CONSOLE_POLL
431 .poll_get_char = altera_uart_poll_get_char,
432 .poll_put_char = altera_uart_poll_put_char,
436 static struct altera_uart altera_uart_ports[CONFIG_SERIAL_ALTERA_UART_MAXPORTS];
438 #if defined(CONFIG_SERIAL_ALTERA_UART_CONSOLE)
440 static void altera_uart_console_putc(struct uart_port *port, int c)
442 while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
443 ALTERA_UART_STATUS_TRDY_MSK))
446 altera_uart_writel(port, c, ALTERA_UART_TXDATA_REG);
449 static void altera_uart_console_write(struct console *co, const char *s,
452 struct uart_port *port = &(altera_uart_ports + co->index)->port;
454 uart_console_write(port, s, count, altera_uart_console_putc);
457 static int __init altera_uart_console_setup(struct console *co, char *options)
459 struct uart_port *port;
460 int baud = CONFIG_SERIAL_ALTERA_UART_BAUDRATE;
465 if (co->index < 0 || co->index >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
467 port = &altera_uart_ports[co->index].port;
472 uart_parse_options(options, &baud, &parity, &bits, &flow);
474 return uart_set_options(port, co, baud, parity, bits, flow);
477 static struct uart_driver altera_uart_driver;
479 static struct console altera_uart_console = {
481 .write = altera_uart_console_write,
482 .device = uart_console_device,
483 .setup = altera_uart_console_setup,
484 .flags = CON_PRINTBUFFER,
486 .data = &altera_uart_driver,
489 static int __init altera_uart_console_init(void)
491 register_console(&altera_uart_console);
495 console_initcall(altera_uart_console_init);
497 #define ALTERA_UART_CONSOLE (&altera_uart_console)
499 static void altera_uart_earlycon_write(struct console *co, const char *s,
502 struct earlycon_device *dev = co->data;
504 uart_console_write(&dev->port, s, count, altera_uart_console_putc);
507 static int __init altera_uart_earlycon_setup(struct earlycon_device *dev,
510 struct uart_port *port = &dev->port;
515 /* Enable RX interrupts now */
516 altera_uart_writel(port, ALTERA_UART_CONTROL_RRDY_MSK,
517 ALTERA_UART_CONTROL_REG);
520 unsigned int baudclk = port->uartclk / dev->baud;
522 altera_uart_writel(port, baudclk, ALTERA_UART_DIVISOR_REG);
525 dev->con->write = altera_uart_earlycon_write;
529 OF_EARLYCON_DECLARE(uart, "altr,uart-1.0", altera_uart_earlycon_setup);
533 #define ALTERA_UART_CONSOLE NULL
535 #endif /* CONFIG_SERIAL_ALTERA_UART_CONSOLE */
538 * Define the altera_uart UART driver structure.
540 static struct uart_driver altera_uart_driver = {
541 .owner = THIS_MODULE,
542 .driver_name = DRV_NAME,
544 .major = SERIAL_ALTERA_MAJOR,
545 .minor = SERIAL_ALTERA_MINOR,
546 .nr = CONFIG_SERIAL_ALTERA_UART_MAXPORTS,
547 .cons = ALTERA_UART_CONSOLE,
550 static int altera_uart_probe(struct platform_device *pdev)
552 struct altera_uart_platform_uart *platp = dev_get_platdata(&pdev->dev);
553 struct uart_port *port;
554 struct resource *res_mem;
555 struct resource *res_irq;
559 /* if id is -1 scan for a free id and use that one */
561 for (i = 0; i < CONFIG_SERIAL_ALTERA_UART_MAXPORTS; i++)
562 if (altera_uart_ports[i].port.mapbase == 0)
566 if (i < 0 || i >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
569 port = &altera_uart_ports[i].port;
571 res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
573 port->mapbase = res_mem->start;
575 port->mapbase = platp->mapbase;
579 res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
581 port->irq = res_irq->start;
583 port->irq = platp->irq;
585 /* Check platform data first so we can override device node data */
587 port->uartclk = platp->uartclk;
589 ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency",
595 port->membase = ioremap(port->mapbase, ALTERA_UART_SIZE);
600 port->regshift = platp->bus_shift;
605 port->type = PORT_ALTERA_UART;
606 port->iotype = SERIAL_IO_MEM;
607 port->ops = &altera_uart_ops;
608 port->flags = UPF_BOOT_AUTOCONF;
609 port->dev = &pdev->dev;
611 platform_set_drvdata(pdev, port);
613 uart_add_one_port(&altera_uart_driver, port);
618 static int altera_uart_remove(struct platform_device *pdev)
620 struct uart_port *port = platform_get_drvdata(pdev);
623 uart_remove_one_port(&altera_uart_driver, port);
625 iounmap(port->membase);
632 static const struct of_device_id altera_uart_match[] = {
633 { .compatible = "ALTR,uart-1.0", },
634 { .compatible = "altr,uart-1.0", },
637 MODULE_DEVICE_TABLE(of, altera_uart_match);
638 #endif /* CONFIG_OF */
640 static struct platform_driver altera_uart_platform_driver = {
641 .probe = altera_uart_probe,
642 .remove = altera_uart_remove,
645 .of_match_table = of_match_ptr(altera_uart_match),
649 static int __init altera_uart_init(void)
653 rc = uart_register_driver(&altera_uart_driver);
656 rc = platform_driver_register(&altera_uart_platform_driver);
658 uart_unregister_driver(&altera_uart_driver);
662 static void __exit altera_uart_exit(void)
664 platform_driver_unregister(&altera_uart_platform_driver);
665 uart_unregister_driver(&altera_uart_driver);
668 module_init(altera_uart_init);
669 module_exit(altera_uart_exit);
671 MODULE_DESCRIPTION("Altera UART driver");
672 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
673 MODULE_LICENSE("GPL");
674 MODULE_ALIAS("platform:" DRV_NAME);
675 MODULE_ALIAS_CHARDEV_MAJOR(SERIAL_ALTERA_MAJOR);