xref: /openbmc/linux/drivers/tty/serial/altera_uart.c (revision 99a15348) 
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * altera_uart.c -- Altera UART driver
4  *
5  * Based on mcf.c -- Freescale ColdFire UART driver
6  *
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>
10  */
11 
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>
23 #include <linux/of.h>
24 #include <linux/io.h>
25 #include <linux/altera_uart.h>
26 
27 #define DRV_NAME "altera_uart"
28 #define SERIAL_ALTERA_MAJOR 204
29 #define SERIAL_ALTERA_MINOR 213
30 
31 /*
32  * Altera UART register definitions according to the Nios UART datasheet:
33  * http://www.altera.com/literature/ds/ds_nios_uart.pdf
34  */
35 
36 #define ALTERA_UART_SIZE		32
37 
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
44 
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 */
57 
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*/
68 
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 */
73 
74 /*
75  * Local per-uart structure.
76  */
77 struct altera_uart {
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 */
82 };
83 
84 static u32 altera_uart_readl(struct uart_port *port, int reg)
85 {
86 	return readl(port->membase + (reg << port->regshift));
87 }
88 
89 static void altera_uart_writel(struct uart_port *port, u32 dat, int reg)
90 {
91 	writel(dat, port->membase + (reg << port->regshift));
92 }
93 
94 static unsigned int altera_uart_tx_empty(struct uart_port *port)
95 {
96 	return (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
97 		ALTERA_UART_STATUS_TMT_MSK) ? TIOCSER_TEMT : 0;
98 }
99 
100 static unsigned int altera_uart_get_mctrl(struct uart_port *port)
101 {
102 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
103 	unsigned int sigs;
104 
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);
108 
109 	return sigs;
110 }
111 
112 static void altera_uart_update_ctrl_reg(struct altera_uart *pp)
113 {
114 	unsigned short imr = pp->imr;
115 
116 	/*
117 	 * If the device doesn't have an irq, ensure that the irq bits are
118 	 * masked out to keep the irq line inactive.
119 	 */
120 	if (!pp->port.irq)
121 		imr &= ALTERA_UART_CONTROL_TRBK_MSK | ALTERA_UART_CONTROL_RTS_MSK;
122 
123 	altera_uart_writel(&pp->port, imr, ALTERA_UART_CONTROL_REG);
124 }
125 
126 static void altera_uart_set_mctrl(struct uart_port *port, unsigned int sigs)
127 {
128 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
129 
130 	pp->sigs = sigs;
131 	if (sigs & TIOCM_RTS)
132 		pp->imr |= ALTERA_UART_CONTROL_RTS_MSK;
133 	else
134 		pp->imr &= ~ALTERA_UART_CONTROL_RTS_MSK;
135 	altera_uart_update_ctrl_reg(pp);
136 }
137 
138 static void altera_uart_start_tx(struct uart_port *port)
139 {
140 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
141 
142 	pp->imr |= ALTERA_UART_CONTROL_TRDY_MSK;
143 	altera_uart_update_ctrl_reg(pp);
144 }
145 
146 static void altera_uart_stop_tx(struct uart_port *port)
147 {
148 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
149 
150 	pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
151 	altera_uart_update_ctrl_reg(pp);
152 }
153 
154 static void altera_uart_stop_rx(struct uart_port *port)
155 {
156 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
157 
158 	pp->imr &= ~ALTERA_UART_CONTROL_RRDY_MSK;
159 	altera_uart_update_ctrl_reg(pp);
160 }
161 
162 static void altera_uart_break_ctl(struct uart_port *port, int break_state)
163 {
164 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
165 	unsigned long flags;
166 
167 	spin_lock_irqsave(&port->lock, flags);
168 	if (break_state == -1)
169 		pp->imr |= ALTERA_UART_CONTROL_TRBK_MSK;
170 	else
171 		pp->imr &= ~ALTERA_UART_CONTROL_TRBK_MSK;
172 	altera_uart_update_ctrl_reg(pp);
173 	spin_unlock_irqrestore(&port->lock, flags);
174 }
175 
176 static void altera_uart_set_termios(struct uart_port *port,
177 				    struct ktermios *termios,
178 				    struct ktermios *old)
179 {
180 	unsigned long flags;
181 	unsigned int baud, baudclk;
182 
183 	baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
184 	baudclk = port->uartclk / baud;
185 
186 	if (old)
187 		tty_termios_copy_hw(termios, old);
188 	tty_termios_encode_baud_rate(termios, baud, baud);
189 
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);
194 
195 	/*
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
199 	 */
200 }
201 
202 static void altera_uart_rx_chars(struct altera_uart *pp)
203 {
204 	struct uart_port *port = &pp->port;
205 	unsigned char ch, flag;
206 	unsigned short status;
207 
208 	while ((status = altera_uart_readl(port, ALTERA_UART_STATUS_REG)) &
209 	       ALTERA_UART_STATUS_RRDY_MSK) {
210 		ch = altera_uart_readl(port, ALTERA_UART_RXDATA_REG);
211 		flag = TTY_NORMAL;
212 		port->icount.rx++;
213 
214 		if (status & ALTERA_UART_STATUS_E_MSK) {
215 			altera_uart_writel(port, status,
216 					   ALTERA_UART_STATUS_REG);
217 
218 			if (status & ALTERA_UART_STATUS_BRK_MSK) {
219 				port->icount.brk++;
220 				if (uart_handle_break(port))
221 					continue;
222 			} else if (status & ALTERA_UART_STATUS_PE_MSK) {
223 				port->icount.parity++;
224 			} else if (status & ALTERA_UART_STATUS_ROE_MSK) {
225 				port->icount.overrun++;
226 			} else if (status & ALTERA_UART_STATUS_FE_MSK) {
227 				port->icount.frame++;
228 			}
229 
230 			status &= port->read_status_mask;
231 
232 			if (status & ALTERA_UART_STATUS_BRK_MSK)
233 				flag = TTY_BREAK;
234 			else if (status & ALTERA_UART_STATUS_PE_MSK)
235 				flag = TTY_PARITY;
236 			else if (status & ALTERA_UART_STATUS_FE_MSK)
237 				flag = TTY_FRAME;
238 		}
239 
240 		if (uart_handle_sysrq_char(port, ch))
241 			continue;
242 		uart_insert_char(port, status, ALTERA_UART_STATUS_ROE_MSK, ch,
243 				 flag);
244 	}
245 
246 	tty_flip_buffer_push(&port->state->port);
247 }
248 
249 static void altera_uart_tx_chars(struct altera_uart *pp)
250 {
251 	struct uart_port *port = &pp->port;
252 	struct circ_buf *xmit = &port->state->xmit;
253 
254 	if (port->x_char) {
255 		/* Send special char - probably flow control */
256 		altera_uart_writel(port, port->x_char, ALTERA_UART_TXDATA_REG);
257 		port->x_char = 0;
258 		port->icount.tx++;
259 		return;
260 	}
261 
262 	while (altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
263 	       ALTERA_UART_STATUS_TRDY_MSK) {
264 		if (xmit->head == xmit->tail)
265 			break;
266 		altera_uart_writel(port, xmit->buf[xmit->tail],
267 		       ALTERA_UART_TXDATA_REG);
268 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
269 		port->icount.tx++;
270 	}
271 
272 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
273 		uart_write_wakeup(port);
274 
275 	if (xmit->head == xmit->tail) {
276 		pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
277 		altera_uart_update_ctrl_reg(pp);
278 	}
279 }
280 
281 static irqreturn_t altera_uart_interrupt(int irq, void *data)
282 {
283 	struct uart_port *port = data;
284 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
285 	unsigned int isr;
286 
287 	isr = altera_uart_readl(port, ALTERA_UART_STATUS_REG) & pp->imr;
288 
289 	spin_lock(&port->lock);
290 	if (isr & ALTERA_UART_STATUS_RRDY_MSK)
291 		altera_uart_rx_chars(pp);
292 	if (isr & ALTERA_UART_STATUS_TRDY_MSK)
293 		altera_uart_tx_chars(pp);
294 	spin_unlock(&port->lock);
295 
296 	return IRQ_RETVAL(isr);
297 }
298 
299 static void altera_uart_timer(struct timer_list *t)
300 {
301 	struct altera_uart *pp = from_timer(pp, t, tmr);
302 	struct uart_port *port = &pp->port;
303 
304 	altera_uart_interrupt(0, port);
305 	mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
306 }
307 
308 static void altera_uart_config_port(struct uart_port *port, int flags)
309 {
310 	port->type = PORT_ALTERA_UART;
311 
312 	/* Clear mask, so no surprise interrupts. */
313 	altera_uart_writel(port, 0, ALTERA_UART_CONTROL_REG);
314 	/* Clear status register */
315 	altera_uart_writel(port, 0, ALTERA_UART_STATUS_REG);
316 }
317 
318 static int altera_uart_startup(struct uart_port *port)
319 {
320 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
321 	unsigned long flags;
322 
323 	if (!port->irq) {
324 		timer_setup(&pp->tmr, altera_uart_timer, 0);
325 		mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
326 	} else {
327 		int ret;
328 
329 		ret = request_irq(port->irq, altera_uart_interrupt, 0,
330 				DRV_NAME, port);
331 		if (ret) {
332 			pr_err(DRV_NAME ": unable to attach Altera UART %d "
333 			       "interrupt vector=%d\n", port->line, port->irq);
334 			return ret;
335 		}
336 	}
337 
338 	spin_lock_irqsave(&port->lock, flags);
339 
340 	/* Enable RX interrupts now */
341 	pp->imr = ALTERA_UART_CONTROL_RRDY_MSK;
342 	altera_uart_update_ctrl_reg(pp);
343 
344 	spin_unlock_irqrestore(&port->lock, flags);
345 
346 	return 0;
347 }
348 
349 static void altera_uart_shutdown(struct uart_port *port)
350 {
351 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
352 	unsigned long flags;
353 
354 	spin_lock_irqsave(&port->lock, flags);
355 
356 	/* Disable all interrupts now */
357 	pp->imr = 0;
358 	altera_uart_update_ctrl_reg(pp);
359 
360 	spin_unlock_irqrestore(&port->lock, flags);
361 
362 	if (port->irq)
363 		free_irq(port->irq, port);
364 	else
365 		del_timer_sync(&pp->tmr);
366 }
367 
368 static const char *altera_uart_type(struct uart_port *port)
369 {
370 	return (port->type == PORT_ALTERA_UART) ? "Altera UART" : NULL;
371 }
372 
373 static int altera_uart_request_port(struct uart_port *port)
374 {
375 	/* UARTs always present */
376 	return 0;
377 }
378 
379 static void altera_uart_release_port(struct uart_port *port)
380 {
381 	/* Nothing to release... */
382 }
383 
384 static int altera_uart_verify_port(struct uart_port *port,
385 				   struct serial_struct *ser)
386 {
387 	if ((ser->type != PORT_UNKNOWN) && (ser->type != PORT_ALTERA_UART))
388 		return -EINVAL;
389 	return 0;
390 }
391 
392 #ifdef CONFIG_CONSOLE_POLL
393 static int altera_uart_poll_get_char(struct uart_port *port)
394 {
395 	while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
396 		 ALTERA_UART_STATUS_RRDY_MSK))
397 		cpu_relax();
398 
399 	return altera_uart_readl(port, ALTERA_UART_RXDATA_REG);
400 }
401 
402 static void altera_uart_poll_put_char(struct uart_port *port, unsigned char c)
403 {
404 	while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
405 		 ALTERA_UART_STATUS_TRDY_MSK))
406 		cpu_relax();
407 
408 	altera_uart_writel(port, c, ALTERA_UART_TXDATA_REG);
409 }
410 #endif
411 
412 /*
413  *	Define the basic serial functions we support.
414  */
415 static const struct uart_ops altera_uart_ops = {
416 	.tx_empty	= altera_uart_tx_empty,
417 	.get_mctrl	= altera_uart_get_mctrl,
418 	.set_mctrl	= altera_uart_set_mctrl,
419 	.start_tx	= altera_uart_start_tx,
420 	.stop_tx	= altera_uart_stop_tx,
421 	.stop_rx	= altera_uart_stop_rx,
422 	.break_ctl	= altera_uart_break_ctl,
423 	.startup	= altera_uart_startup,
424 	.shutdown	= altera_uart_shutdown,
425 	.set_termios	= altera_uart_set_termios,
426 	.type		= altera_uart_type,
427 	.request_port	= altera_uart_request_port,
428 	.release_port	= altera_uart_release_port,
429 	.config_port	= altera_uart_config_port,
430 	.verify_port	= altera_uart_verify_port,
431 #ifdef CONFIG_CONSOLE_POLL
432 	.poll_get_char	= altera_uart_poll_get_char,
433 	.poll_put_char	= altera_uart_poll_put_char,
434 #endif
435 };
436 
437 static struct altera_uart altera_uart_ports[CONFIG_SERIAL_ALTERA_UART_MAXPORTS];
438 
439 #if defined(CONFIG_SERIAL_ALTERA_UART_CONSOLE)
440 
441 static void altera_uart_console_putc(struct uart_port *port, unsigned char c)
442 {
443 	while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
444 		 ALTERA_UART_STATUS_TRDY_MSK))
445 		cpu_relax();
446 
447 	altera_uart_writel(port, c, ALTERA_UART_TXDATA_REG);
448 }
449 
450 static void altera_uart_console_write(struct console *co, const char *s,
451 				      unsigned int count)
452 {
453 	struct uart_port *port = &(altera_uart_ports + co->index)->port;
454 
455 	uart_console_write(port, s, count, altera_uart_console_putc);
456 }
457 
458 static int __init altera_uart_console_setup(struct console *co, char *options)
459 {
460 	struct uart_port *port;
461 	int baud = CONFIG_SERIAL_ALTERA_UART_BAUDRATE;
462 	int bits = 8;
463 	int parity = 'n';
464 	int flow = 'n';
465 
466 	if (co->index < 0 || co->index >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
467 		return -EINVAL;
468 	port = &altera_uart_ports[co->index].port;
469 	if (!port->membase)
470 		return -ENODEV;
471 
472 	if (options)
473 		uart_parse_options(options, &baud, &parity, &bits, &flow);
474 
475 	return uart_set_options(port, co, baud, parity, bits, flow);
476 }
477 
478 static struct uart_driver altera_uart_driver;
479 
480 static struct console altera_uart_console = {
481 	.name	= "ttyAL",
482 	.write	= altera_uart_console_write,
483 	.device	= uart_console_device,
484 	.setup	= altera_uart_console_setup,
485 	.flags	= CON_PRINTBUFFER,
486 	.index	= -1,
487 	.data	= &altera_uart_driver,
488 };
489 
490 static int __init altera_uart_console_init(void)
491 {
492 	register_console(&altera_uart_console);
493 	return 0;
494 }
495 
496 console_initcall(altera_uart_console_init);
497 
498 #define	ALTERA_UART_CONSOLE	(&altera_uart_console)
499 
500 static void altera_uart_earlycon_write(struct console *co, const char *s,
501 				       unsigned int count)
502 {
503 	struct earlycon_device *dev = co->data;
504 
505 	uart_console_write(&dev->port, s, count, altera_uart_console_putc);
506 }
507 
508 static int __init altera_uart_earlycon_setup(struct earlycon_device *dev,
509 					     const char *options)
510 {
511 	struct uart_port *port = &dev->port;
512 
513 	if (!port->membase)
514 		return -ENODEV;
515 
516 	/* Enable RX interrupts now */
517 	altera_uart_writel(port, ALTERA_UART_CONTROL_RRDY_MSK,
518 			   ALTERA_UART_CONTROL_REG);
519 
520 	if (dev->baud) {
521 		unsigned int baudclk = port->uartclk / dev->baud;
522 
523 		altera_uart_writel(port, baudclk, ALTERA_UART_DIVISOR_REG);
524 	}
525 
526 	dev->con->write = altera_uart_earlycon_write;
527 	return 0;
528 }
529 
530 OF_EARLYCON_DECLARE(uart, "altr,uart-1.0", altera_uart_earlycon_setup);
531 
532 #else
533 
534 #define	ALTERA_UART_CONSOLE	NULL
535 
536 #endif /* CONFIG_SERIAL_ALTERA_UART_CONSOLE */
537 
538 /*
539  *	Define the altera_uart UART driver structure.
540  */
541 static struct uart_driver altera_uart_driver = {
542 	.owner		= THIS_MODULE,
543 	.driver_name	= DRV_NAME,
544 	.dev_name	= "ttyAL",
545 	.major		= SERIAL_ALTERA_MAJOR,
546 	.minor		= SERIAL_ALTERA_MINOR,
547 	.nr		= CONFIG_SERIAL_ALTERA_UART_MAXPORTS,
548 	.cons		= ALTERA_UART_CONSOLE,
549 };
550 
551 static int altera_uart_probe(struct platform_device *pdev)
552 {
553 	struct altera_uart_platform_uart *platp = dev_get_platdata(&pdev->dev);
554 	struct uart_port *port;
555 	struct resource *res_mem;
556 	int i = pdev->id;
557 	int ret;
558 
559 	/* if id is -1 scan for a free id and use that one */
560 	if (i == -1) {
561 		for (i = 0; i < CONFIG_SERIAL_ALTERA_UART_MAXPORTS; i++)
562 			if (altera_uart_ports[i].port.mapbase == 0)
563 				break;
564 	}
565 
566 	if (i < 0 || i >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
567 		return -EINVAL;
568 
569 	port = &altera_uart_ports[i].port;
570 
571 	res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
572 	if (res_mem)
573 		port->mapbase = res_mem->start;
574 	else if (platp)
575 		port->mapbase = platp->mapbase;
576 	else
577 		return -EINVAL;
578 
579 	ret = platform_get_irq_optional(pdev, 0);
580 	if (ret < 0 && ret != -ENXIO)
581 		return ret;
582 	if (ret > 0)
583 		port->irq = ret;
584 	else if (platp)
585 		port->irq = platp->irq;
586 
587 	/* Check platform data first so we can override device node data */
588 	if (platp)
589 		port->uartclk = platp->uartclk;
590 	else {
591 		ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency",
592 					   &port->uartclk);
593 		if (ret)
594 			return ret;
595 	}
596 
597 	port->membase = ioremap(port->mapbase, ALTERA_UART_SIZE);
598 	if (!port->membase)
599 		return -ENOMEM;
600 
601 	if (platp)
602 		port->regshift = platp->bus_shift;
603 	else
604 		port->regshift = 0;
605 
606 	port->line = i;
607 	port->type = PORT_ALTERA_UART;
608 	port->iotype = SERIAL_IO_MEM;
609 	port->ops = &altera_uart_ops;
610 	port->flags = UPF_BOOT_AUTOCONF;
611 	port->dev = &pdev->dev;
612 
613 	platform_set_drvdata(pdev, port);
614 
615 	uart_add_one_port(&altera_uart_driver, port);
616 
617 	return 0;
618 }
619 
620 static int altera_uart_remove(struct platform_device *pdev)
621 {
622 	struct uart_port *port = platform_get_drvdata(pdev);
623 
624 	if (port) {
625 		uart_remove_one_port(&altera_uart_driver, port);
626 		port->mapbase = 0;
627 		iounmap(port->membase);
628 	}
629 
630 	return 0;
631 }
632 
633 #ifdef CONFIG_OF
634 static const struct of_device_id altera_uart_match[] = {
635 	{ .compatible = "ALTR,uart-1.0", },
636 	{ .compatible = "altr,uart-1.0", },
637 	{},
638 };
639 MODULE_DEVICE_TABLE(of, altera_uart_match);
640 #endif /* CONFIG_OF */
641 
642 static struct platform_driver altera_uart_platform_driver = {
643 	.probe	= altera_uart_probe,
644 	.remove	= altera_uart_remove,
645 	.driver	= {
646 		.name		= DRV_NAME,
647 		.of_match_table	= of_match_ptr(altera_uart_match),
648 	},
649 };
650 
651 static int __init altera_uart_init(void)
652 {
653 	int rc;
654 
655 	rc = uart_register_driver(&altera_uart_driver);
656 	if (rc)
657 		return rc;
658 	rc = platform_driver_register(&altera_uart_platform_driver);
659 	if (rc)
660 		uart_unregister_driver(&altera_uart_driver);
661 	return rc;
662 }
663 
664 static void __exit altera_uart_exit(void)
665 {
666 	platform_driver_unregister(&altera_uart_platform_driver);
667 	uart_unregister_driver(&altera_uart_driver);
668 }
669 
670 module_init(altera_uart_init);
671 module_exit(altera_uart_exit);
672 
673 MODULE_DESCRIPTION("Altera UART driver");
674 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
675 MODULE_LICENSE("GPL");
676 MODULE_ALIAS("platform:" DRV_NAME);
677 MODULE_ALIAS_CHARDEV_MAJOR(SERIAL_ALTERA_MAJOR);
678