xref: /openbmc/linux/drivers/tty/serial/lantiq.c (revision 4f3db074)
1 /*
2  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms of the GNU General Public License version 2 as published
6  * by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11  * GNU General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public License
14  * along with this program; if not, write to the Free Software
15  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
16  *
17  * Copyright (C) 2004 Infineon IFAP DC COM CPE
18  * Copyright (C) 2007 Felix Fietkau <nbd@openwrt.org>
19  * Copyright (C) 2007 John Crispin <blogic@openwrt.org>
20  * Copyright (C) 2010 Thomas Langer, <thomas.langer@lantiq.com>
21  */
22 
23 #include <linux/slab.h>
24 #include <linux/module.h>
25 #include <linux/ioport.h>
26 #include <linux/init.h>
27 #include <linux/console.h>
28 #include <linux/sysrq.h>
29 #include <linux/device.h>
30 #include <linux/tty.h>
31 #include <linux/tty_flip.h>
32 #include <linux/serial_core.h>
33 #include <linux/serial.h>
34 #include <linux/of_platform.h>
35 #include <linux/of_address.h>
36 #include <linux/of_irq.h>
37 #include <linux/io.h>
38 #include <linux/clk.h>
39 #include <linux/gpio.h>
40 
41 #include <lantiq_soc.h>
42 
43 #define PORT_LTQ_ASC		111
44 #define MAXPORTS		2
45 #define UART_DUMMY_UER_RX	1
46 #define DRVNAME			"lantiq,asc"
47 #ifdef __BIG_ENDIAN
48 #define LTQ_ASC_TBUF		(0x0020 + 3)
49 #define LTQ_ASC_RBUF		(0x0024 + 3)
50 #else
51 #define LTQ_ASC_TBUF		0x0020
52 #define LTQ_ASC_RBUF		0x0024
53 #endif
54 #define LTQ_ASC_FSTAT		0x0048
55 #define LTQ_ASC_WHBSTATE	0x0018
56 #define LTQ_ASC_STATE		0x0014
57 #define LTQ_ASC_IRNCR		0x00F8
58 #define LTQ_ASC_CLC		0x0000
59 #define LTQ_ASC_ID		0x0008
60 #define LTQ_ASC_PISEL		0x0004
61 #define LTQ_ASC_TXFCON		0x0044
62 #define LTQ_ASC_RXFCON		0x0040
63 #define LTQ_ASC_CON		0x0010
64 #define LTQ_ASC_BG		0x0050
65 #define LTQ_ASC_IRNREN		0x00F4
66 
67 #define ASC_IRNREN_TX		0x1
68 #define ASC_IRNREN_RX		0x2
69 #define ASC_IRNREN_ERR		0x4
70 #define ASC_IRNREN_TX_BUF	0x8
71 #define ASC_IRNCR_TIR		0x1
72 #define ASC_IRNCR_RIR		0x2
73 #define ASC_IRNCR_EIR		0x4
74 
75 #define ASCOPT_CSIZE		0x3
76 #define TXFIFO_FL		1
77 #define RXFIFO_FL		1
78 #define ASCCLC_DISS		0x2
79 #define ASCCLC_RMCMASK		0x0000FF00
80 #define ASCCLC_RMCOFFSET	8
81 #define ASCCON_M_8ASYNC		0x0
82 #define ASCCON_M_7ASYNC		0x2
83 #define ASCCON_ODD		0x00000020
84 #define ASCCON_STP		0x00000080
85 #define ASCCON_BRS		0x00000100
86 #define ASCCON_FDE		0x00000200
87 #define ASCCON_R		0x00008000
88 #define ASCCON_FEN		0x00020000
89 #define ASCCON_ROEN		0x00080000
90 #define ASCCON_TOEN		0x00100000
91 #define ASCSTATE_PE		0x00010000
92 #define ASCSTATE_FE		0x00020000
93 #define ASCSTATE_ROE		0x00080000
94 #define ASCSTATE_ANY		(ASCSTATE_ROE|ASCSTATE_PE|ASCSTATE_FE)
95 #define ASCWHBSTATE_CLRREN	0x00000001
96 #define ASCWHBSTATE_SETREN	0x00000002
97 #define ASCWHBSTATE_CLRPE	0x00000004
98 #define ASCWHBSTATE_CLRFE	0x00000008
99 #define ASCWHBSTATE_CLRROE	0x00000020
100 #define ASCTXFCON_TXFEN		0x0001
101 #define ASCTXFCON_TXFFLU	0x0002
102 #define ASCTXFCON_TXFITLMASK	0x3F00
103 #define ASCTXFCON_TXFITLOFF	8
104 #define ASCRXFCON_RXFEN		0x0001
105 #define ASCRXFCON_RXFFLU	0x0002
106 #define ASCRXFCON_RXFITLMASK	0x3F00
107 #define ASCRXFCON_RXFITLOFF	8
108 #define ASCFSTAT_RXFFLMASK	0x003F
109 #define ASCFSTAT_TXFFLMASK	0x3F00
110 #define ASCFSTAT_TXFREEMASK	0x3F000000
111 #define ASCFSTAT_TXFREEOFF	24
112 
113 static void lqasc_tx_chars(struct uart_port *port);
114 static struct ltq_uart_port *lqasc_port[MAXPORTS];
115 static struct uart_driver lqasc_reg;
116 static DEFINE_SPINLOCK(ltq_asc_lock);
117 
118 struct ltq_uart_port {
119 	struct uart_port	port;
120 	/* clock used to derive divider */
121 	struct clk		*fpiclk;
122 	/* clock gating of the ASC core */
123 	struct clk		*clk;
124 	unsigned int		tx_irq;
125 	unsigned int		rx_irq;
126 	unsigned int		err_irq;
127 };
128 
129 static inline struct
130 ltq_uart_port *to_ltq_uart_port(struct uart_port *port)
131 {
132 	return container_of(port, struct ltq_uart_port, port);
133 }
134 
135 static void
136 lqasc_stop_tx(struct uart_port *port)
137 {
138 	return;
139 }
140 
141 static void
142 lqasc_start_tx(struct uart_port *port)
143 {
144 	unsigned long flags;
145 	spin_lock_irqsave(&ltq_asc_lock, flags);
146 	lqasc_tx_chars(port);
147 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
148 	return;
149 }
150 
151 static void
152 lqasc_stop_rx(struct uart_port *port)
153 {
154 	ltq_w32(ASCWHBSTATE_CLRREN, port->membase + LTQ_ASC_WHBSTATE);
155 }
156 
157 static int
158 lqasc_rx_chars(struct uart_port *port)
159 {
160 	struct tty_port *tport = &port->state->port;
161 	unsigned int ch = 0, rsr = 0, fifocnt;
162 
163 	fifocnt = ltq_r32(port->membase + LTQ_ASC_FSTAT) & ASCFSTAT_RXFFLMASK;
164 	while (fifocnt--) {
165 		u8 flag = TTY_NORMAL;
166 		ch = ltq_r8(port->membase + LTQ_ASC_RBUF);
167 		rsr = (ltq_r32(port->membase + LTQ_ASC_STATE)
168 			& ASCSTATE_ANY) | UART_DUMMY_UER_RX;
169 		tty_flip_buffer_push(tport);
170 		port->icount.rx++;
171 
172 		/*
173 		 * Note that the error handling code is
174 		 * out of the main execution path
175 		 */
176 		if (rsr & ASCSTATE_ANY) {
177 			if (rsr & ASCSTATE_PE) {
178 				port->icount.parity++;
179 				ltq_w32_mask(0, ASCWHBSTATE_CLRPE,
180 					port->membase + LTQ_ASC_WHBSTATE);
181 			} else if (rsr & ASCSTATE_FE) {
182 				port->icount.frame++;
183 				ltq_w32_mask(0, ASCWHBSTATE_CLRFE,
184 					port->membase + LTQ_ASC_WHBSTATE);
185 			}
186 			if (rsr & ASCSTATE_ROE) {
187 				port->icount.overrun++;
188 				ltq_w32_mask(0, ASCWHBSTATE_CLRROE,
189 					port->membase + LTQ_ASC_WHBSTATE);
190 			}
191 
192 			rsr &= port->read_status_mask;
193 
194 			if (rsr & ASCSTATE_PE)
195 				flag = TTY_PARITY;
196 			else if (rsr & ASCSTATE_FE)
197 				flag = TTY_FRAME;
198 		}
199 
200 		if ((rsr & port->ignore_status_mask) == 0)
201 			tty_insert_flip_char(tport, ch, flag);
202 
203 		if (rsr & ASCSTATE_ROE)
204 			/*
205 			 * Overrun is special, since it's reported
206 			 * immediately, and doesn't affect the current
207 			 * character
208 			 */
209 			tty_insert_flip_char(tport, 0, TTY_OVERRUN);
210 	}
211 
212 	if (ch != 0)
213 		tty_flip_buffer_push(tport);
214 
215 	return 0;
216 }
217 
218 static void
219 lqasc_tx_chars(struct uart_port *port)
220 {
221 	struct circ_buf *xmit = &port->state->xmit;
222 	if (uart_tx_stopped(port)) {
223 		lqasc_stop_tx(port);
224 		return;
225 	}
226 
227 	while (((ltq_r32(port->membase + LTQ_ASC_FSTAT) &
228 		ASCFSTAT_TXFREEMASK) >> ASCFSTAT_TXFREEOFF) != 0) {
229 		if (port->x_char) {
230 			ltq_w8(port->x_char, port->membase + LTQ_ASC_TBUF);
231 			port->icount.tx++;
232 			port->x_char = 0;
233 			continue;
234 		}
235 
236 		if (uart_circ_empty(xmit))
237 			break;
238 
239 		ltq_w8(port->state->xmit.buf[port->state->xmit.tail],
240 			port->membase + LTQ_ASC_TBUF);
241 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
242 		port->icount.tx++;
243 	}
244 
245 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
246 		uart_write_wakeup(port);
247 }
248 
249 static irqreturn_t
250 lqasc_tx_int(int irq, void *_port)
251 {
252 	unsigned long flags;
253 	struct uart_port *port = (struct uart_port *)_port;
254 	spin_lock_irqsave(&ltq_asc_lock, flags);
255 	ltq_w32(ASC_IRNCR_TIR, port->membase + LTQ_ASC_IRNCR);
256 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
257 	lqasc_start_tx(port);
258 	return IRQ_HANDLED;
259 }
260 
261 static irqreturn_t
262 lqasc_err_int(int irq, void *_port)
263 {
264 	unsigned long flags;
265 	struct uart_port *port = (struct uart_port *)_port;
266 	spin_lock_irqsave(&ltq_asc_lock, flags);
267 	/* clear any pending interrupts */
268 	ltq_w32_mask(0, ASCWHBSTATE_CLRPE | ASCWHBSTATE_CLRFE |
269 		ASCWHBSTATE_CLRROE, port->membase + LTQ_ASC_WHBSTATE);
270 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
271 	return IRQ_HANDLED;
272 }
273 
274 static irqreturn_t
275 lqasc_rx_int(int irq, void *_port)
276 {
277 	unsigned long flags;
278 	struct uart_port *port = (struct uart_port *)_port;
279 	spin_lock_irqsave(&ltq_asc_lock, flags);
280 	ltq_w32(ASC_IRNCR_RIR, port->membase + LTQ_ASC_IRNCR);
281 	lqasc_rx_chars(port);
282 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
283 	return IRQ_HANDLED;
284 }
285 
286 static unsigned int
287 lqasc_tx_empty(struct uart_port *port)
288 {
289 	int status;
290 	status = ltq_r32(port->membase + LTQ_ASC_FSTAT) & ASCFSTAT_TXFFLMASK;
291 	return status ? 0 : TIOCSER_TEMT;
292 }
293 
294 static unsigned int
295 lqasc_get_mctrl(struct uart_port *port)
296 {
297 	return TIOCM_CTS | TIOCM_CAR | TIOCM_DSR;
298 }
299 
300 static void
301 lqasc_set_mctrl(struct uart_port *port, u_int mctrl)
302 {
303 }
304 
305 static void
306 lqasc_break_ctl(struct uart_port *port, int break_state)
307 {
308 }
309 
310 static int
311 lqasc_startup(struct uart_port *port)
312 {
313 	struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
314 	int retval;
315 
316 	if (!IS_ERR(ltq_port->clk))
317 		clk_enable(ltq_port->clk);
318 	port->uartclk = clk_get_rate(ltq_port->fpiclk);
319 
320 	ltq_w32_mask(ASCCLC_DISS | ASCCLC_RMCMASK, (1 << ASCCLC_RMCOFFSET),
321 		port->membase + LTQ_ASC_CLC);
322 
323 	ltq_w32(0, port->membase + LTQ_ASC_PISEL);
324 	ltq_w32(
325 		((TXFIFO_FL << ASCTXFCON_TXFITLOFF) & ASCTXFCON_TXFITLMASK) |
326 		ASCTXFCON_TXFEN | ASCTXFCON_TXFFLU,
327 		port->membase + LTQ_ASC_TXFCON);
328 	ltq_w32(
329 		((RXFIFO_FL << ASCRXFCON_RXFITLOFF) & ASCRXFCON_RXFITLMASK)
330 		| ASCRXFCON_RXFEN | ASCRXFCON_RXFFLU,
331 		port->membase + LTQ_ASC_RXFCON);
332 	/* make sure other settings are written to hardware before
333 	 * setting enable bits
334 	 */
335 	wmb();
336 	ltq_w32_mask(0, ASCCON_M_8ASYNC | ASCCON_FEN | ASCCON_TOEN |
337 		ASCCON_ROEN, port->membase + LTQ_ASC_CON);
338 
339 	retval = request_irq(ltq_port->tx_irq, lqasc_tx_int,
340 		0, "asc_tx", port);
341 	if (retval) {
342 		pr_err("failed to request lqasc_tx_int\n");
343 		return retval;
344 	}
345 
346 	retval = request_irq(ltq_port->rx_irq, lqasc_rx_int,
347 		0, "asc_rx", port);
348 	if (retval) {
349 		pr_err("failed to request lqasc_rx_int\n");
350 		goto err1;
351 	}
352 
353 	retval = request_irq(ltq_port->err_irq, lqasc_err_int,
354 		0, "asc_err", port);
355 	if (retval) {
356 		pr_err("failed to request lqasc_err_int\n");
357 		goto err2;
358 	}
359 
360 	ltq_w32(ASC_IRNREN_RX | ASC_IRNREN_ERR | ASC_IRNREN_TX,
361 		port->membase + LTQ_ASC_IRNREN);
362 	return 0;
363 
364 err2:
365 	free_irq(ltq_port->rx_irq, port);
366 err1:
367 	free_irq(ltq_port->tx_irq, port);
368 	return retval;
369 }
370 
371 static void
372 lqasc_shutdown(struct uart_port *port)
373 {
374 	struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
375 	free_irq(ltq_port->tx_irq, port);
376 	free_irq(ltq_port->rx_irq, port);
377 	free_irq(ltq_port->err_irq, port);
378 
379 	ltq_w32(0, port->membase + LTQ_ASC_CON);
380 	ltq_w32_mask(ASCRXFCON_RXFEN, ASCRXFCON_RXFFLU,
381 		port->membase + LTQ_ASC_RXFCON);
382 	ltq_w32_mask(ASCTXFCON_TXFEN, ASCTXFCON_TXFFLU,
383 		port->membase + LTQ_ASC_TXFCON);
384 	if (!IS_ERR(ltq_port->clk))
385 		clk_disable(ltq_port->clk);
386 }
387 
388 static void
389 lqasc_set_termios(struct uart_port *port,
390 	struct ktermios *new, struct ktermios *old)
391 {
392 	unsigned int cflag;
393 	unsigned int iflag;
394 	unsigned int divisor;
395 	unsigned int baud;
396 	unsigned int con = 0;
397 	unsigned long flags;
398 
399 	cflag = new->c_cflag;
400 	iflag = new->c_iflag;
401 
402 	switch (cflag & CSIZE) {
403 	case CS7:
404 		con = ASCCON_M_7ASYNC;
405 		break;
406 
407 	case CS5:
408 	case CS6:
409 	default:
410 		new->c_cflag &= ~ CSIZE;
411 		new->c_cflag |= CS8;
412 		con = ASCCON_M_8ASYNC;
413 		break;
414 	}
415 
416 	cflag &= ~CMSPAR; /* Mark/Space parity is not supported */
417 
418 	if (cflag & CSTOPB)
419 		con |= ASCCON_STP;
420 
421 	if (cflag & PARENB) {
422 		if (!(cflag & PARODD))
423 			con &= ~ASCCON_ODD;
424 		else
425 			con |= ASCCON_ODD;
426 	}
427 
428 	port->read_status_mask = ASCSTATE_ROE;
429 	if (iflag & INPCK)
430 		port->read_status_mask |= ASCSTATE_FE | ASCSTATE_PE;
431 
432 	port->ignore_status_mask = 0;
433 	if (iflag & IGNPAR)
434 		port->ignore_status_mask |= ASCSTATE_FE | ASCSTATE_PE;
435 
436 	if (iflag & IGNBRK) {
437 		/*
438 		 * If we're ignoring parity and break indicators,
439 		 * ignore overruns too (for real raw support).
440 		 */
441 		if (iflag & IGNPAR)
442 			port->ignore_status_mask |= ASCSTATE_ROE;
443 	}
444 
445 	if ((cflag & CREAD) == 0)
446 		port->ignore_status_mask |= UART_DUMMY_UER_RX;
447 
448 	/* set error signals  - framing, parity  and overrun, enable receiver */
449 	con |= ASCCON_FEN | ASCCON_TOEN | ASCCON_ROEN;
450 
451 	spin_lock_irqsave(&ltq_asc_lock, flags);
452 
453 	/* set up CON */
454 	ltq_w32_mask(0, con, port->membase + LTQ_ASC_CON);
455 
456 	/* Set baud rate - take a divider of 2 into account */
457 	baud = uart_get_baud_rate(port, new, old, 0, port->uartclk / 16);
458 	divisor = uart_get_divisor(port, baud);
459 	divisor = divisor / 2 - 1;
460 
461 	/* disable the baudrate generator */
462 	ltq_w32_mask(ASCCON_R, 0, port->membase + LTQ_ASC_CON);
463 
464 	/* make sure the fractional divider is off */
465 	ltq_w32_mask(ASCCON_FDE, 0, port->membase + LTQ_ASC_CON);
466 
467 	/* set up to use divisor of 2 */
468 	ltq_w32_mask(ASCCON_BRS, 0, port->membase + LTQ_ASC_CON);
469 
470 	/* now we can write the new baudrate into the register */
471 	ltq_w32(divisor, port->membase + LTQ_ASC_BG);
472 
473 	/* turn the baudrate generator back on */
474 	ltq_w32_mask(0, ASCCON_R, port->membase + LTQ_ASC_CON);
475 
476 	/* enable rx */
477 	ltq_w32(ASCWHBSTATE_SETREN, port->membase + LTQ_ASC_WHBSTATE);
478 
479 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
480 
481 	/* Don't rewrite B0 */
482 	if (tty_termios_baud_rate(new))
483 		tty_termios_encode_baud_rate(new, baud, baud);
484 
485 	uart_update_timeout(port, cflag, baud);
486 }
487 
488 static const char*
489 lqasc_type(struct uart_port *port)
490 {
491 	if (port->type == PORT_LTQ_ASC)
492 		return DRVNAME;
493 	else
494 		return NULL;
495 }
496 
497 static void
498 lqasc_release_port(struct uart_port *port)
499 {
500 	struct platform_device *pdev = to_platform_device(port->dev);
501 
502 	if (port->flags & UPF_IOREMAP) {
503 		devm_iounmap(&pdev->dev, port->membase);
504 		port->membase = NULL;
505 	}
506 }
507 
508 static int
509 lqasc_request_port(struct uart_port *port)
510 {
511 	struct platform_device *pdev = to_platform_device(port->dev);
512 	struct resource *res;
513 	int size;
514 
515 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
516 	if (!res) {
517 		dev_err(&pdev->dev, "cannot obtain I/O memory region");
518 		return -ENODEV;
519 	}
520 	size = resource_size(res);
521 
522 	res = devm_request_mem_region(&pdev->dev, res->start,
523 		size, dev_name(&pdev->dev));
524 	if (!res) {
525 		dev_err(&pdev->dev, "cannot request I/O memory region");
526 		return -EBUSY;
527 	}
528 
529 	if (port->flags & UPF_IOREMAP) {
530 		port->membase = devm_ioremap_nocache(&pdev->dev,
531 			port->mapbase, size);
532 		if (port->membase == NULL)
533 			return -ENOMEM;
534 	}
535 	return 0;
536 }
537 
538 static void
539 lqasc_config_port(struct uart_port *port, int flags)
540 {
541 	if (flags & UART_CONFIG_TYPE) {
542 		port->type = PORT_LTQ_ASC;
543 		lqasc_request_port(port);
544 	}
545 }
546 
547 static int
548 lqasc_verify_port(struct uart_port *port,
549 	struct serial_struct *ser)
550 {
551 	int ret = 0;
552 	if (ser->type != PORT_UNKNOWN && ser->type != PORT_LTQ_ASC)
553 		ret = -EINVAL;
554 	if (ser->irq < 0 || ser->irq >= NR_IRQS)
555 		ret = -EINVAL;
556 	if (ser->baud_base < 9600)
557 		ret = -EINVAL;
558 	return ret;
559 }
560 
561 static struct uart_ops lqasc_pops = {
562 	.tx_empty =	lqasc_tx_empty,
563 	.set_mctrl =	lqasc_set_mctrl,
564 	.get_mctrl =	lqasc_get_mctrl,
565 	.stop_tx =	lqasc_stop_tx,
566 	.start_tx =	lqasc_start_tx,
567 	.stop_rx =	lqasc_stop_rx,
568 	.break_ctl =	lqasc_break_ctl,
569 	.startup =	lqasc_startup,
570 	.shutdown =	lqasc_shutdown,
571 	.set_termios =	lqasc_set_termios,
572 	.type =		lqasc_type,
573 	.release_port =	lqasc_release_port,
574 	.request_port =	lqasc_request_port,
575 	.config_port =	lqasc_config_port,
576 	.verify_port =	lqasc_verify_port,
577 };
578 
579 static void
580 lqasc_console_putchar(struct uart_port *port, int ch)
581 {
582 	int fifofree;
583 
584 	if (!port->membase)
585 		return;
586 
587 	do {
588 		fifofree = (ltq_r32(port->membase + LTQ_ASC_FSTAT)
589 			& ASCFSTAT_TXFREEMASK) >> ASCFSTAT_TXFREEOFF;
590 	} while (fifofree == 0);
591 	ltq_w8(ch, port->membase + LTQ_ASC_TBUF);
592 }
593 
594 
595 static void
596 lqasc_console_write(struct console *co, const char *s, u_int count)
597 {
598 	struct ltq_uart_port *ltq_port;
599 	struct uart_port *port;
600 	unsigned long flags;
601 
602 	if (co->index >= MAXPORTS)
603 		return;
604 
605 	ltq_port = lqasc_port[co->index];
606 	if (!ltq_port)
607 		return;
608 
609 	port = &ltq_port->port;
610 
611 	spin_lock_irqsave(&ltq_asc_lock, flags);
612 	uart_console_write(port, s, count, lqasc_console_putchar);
613 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
614 }
615 
616 static int __init
617 lqasc_console_setup(struct console *co, char *options)
618 {
619 	struct ltq_uart_port *ltq_port;
620 	struct uart_port *port;
621 	int baud = 115200;
622 	int bits = 8;
623 	int parity = 'n';
624 	int flow = 'n';
625 
626 	if (co->index >= MAXPORTS)
627 		return -ENODEV;
628 
629 	ltq_port = lqasc_port[co->index];
630 	if (!ltq_port)
631 		return -ENODEV;
632 
633 	port = &ltq_port->port;
634 
635 	if (!IS_ERR(ltq_port->clk))
636 		clk_enable(ltq_port->clk);
637 
638 	port->uartclk = clk_get_rate(ltq_port->fpiclk);
639 
640 	if (options)
641 		uart_parse_options(options, &baud, &parity, &bits, &flow);
642 	return uart_set_options(port, co, baud, parity, bits, flow);
643 }
644 
645 static struct console lqasc_console = {
646 	.name =		"ttyLTQ",
647 	.write =	lqasc_console_write,
648 	.device =	uart_console_device,
649 	.setup =	lqasc_console_setup,
650 	.flags =	CON_PRINTBUFFER,
651 	.index =	-1,
652 	.data =		&lqasc_reg,
653 };
654 
655 static int __init
656 lqasc_console_init(void)
657 {
658 	register_console(&lqasc_console);
659 	return 0;
660 }
661 console_initcall(lqasc_console_init);
662 
663 static struct uart_driver lqasc_reg = {
664 	.owner =	THIS_MODULE,
665 	.driver_name =	DRVNAME,
666 	.dev_name =	"ttyLTQ",
667 	.major =	0,
668 	.minor =	0,
669 	.nr =		MAXPORTS,
670 	.cons =		&lqasc_console,
671 };
672 
673 static int __init
674 lqasc_probe(struct platform_device *pdev)
675 {
676 	struct device_node *node = pdev->dev.of_node;
677 	struct ltq_uart_port *ltq_port;
678 	struct uart_port *port;
679 	struct resource *mmres, irqres[3];
680 	int line = 0;
681 	int ret;
682 
683 	mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
684 	ret = of_irq_to_resource_table(node, irqres, 3);
685 	if (!mmres || (ret != 3)) {
686 		dev_err(&pdev->dev,
687 			"failed to get memory/irq for serial port\n");
688 		return -ENODEV;
689 	}
690 
691 	/* check if this is the console port */
692 	if (mmres->start != CPHYSADDR(LTQ_EARLY_ASC))
693 		line = 1;
694 
695 	if (lqasc_port[line]) {
696 		dev_err(&pdev->dev, "port %d already allocated\n", line);
697 		return -EBUSY;
698 	}
699 
700 	ltq_port = devm_kzalloc(&pdev->dev, sizeof(struct ltq_uart_port),
701 			GFP_KERNEL);
702 	if (!ltq_port)
703 		return -ENOMEM;
704 
705 	port = &ltq_port->port;
706 
707 	port->iotype	= SERIAL_IO_MEM;
708 	port->flags	= UPF_BOOT_AUTOCONF | UPF_IOREMAP;
709 	port->ops	= &lqasc_pops;
710 	port->fifosize	= 16;
711 	port->type	= PORT_LTQ_ASC,
712 	port->line	= line;
713 	port->dev	= &pdev->dev;
714 	/* unused, just to be backward-compatible */
715 	port->irq	= irqres[0].start;
716 	port->mapbase	= mmres->start;
717 
718 	ltq_port->fpiclk = clk_get_fpi();
719 	if (IS_ERR(ltq_port->fpiclk)) {
720 		pr_err("failed to get fpi clk\n");
721 		return -ENOENT;
722 	}
723 
724 	/* not all asc ports have clock gates, lets ignore the return code */
725 	ltq_port->clk = clk_get(&pdev->dev, NULL);
726 
727 	ltq_port->tx_irq = irqres[0].start;
728 	ltq_port->rx_irq = irqres[1].start;
729 	ltq_port->err_irq = irqres[2].start;
730 
731 	lqasc_port[line] = ltq_port;
732 	platform_set_drvdata(pdev, ltq_port);
733 
734 	ret = uart_add_one_port(&lqasc_reg, port);
735 
736 	return ret;
737 }
738 
739 static const struct of_device_id ltq_asc_match[] = {
740 	{ .compatible = DRVNAME },
741 	{},
742 };
743 MODULE_DEVICE_TABLE(of, ltq_asc_match);
744 
745 static struct platform_driver lqasc_driver = {
746 	.driver		= {
747 		.name	= DRVNAME,
748 		.of_match_table = ltq_asc_match,
749 	},
750 };
751 
752 int __init
753 init_lqasc(void)
754 {
755 	int ret;
756 
757 	ret = uart_register_driver(&lqasc_reg);
758 	if (ret != 0)
759 		return ret;
760 
761 	ret = platform_driver_probe(&lqasc_driver, lqasc_probe);
762 	if (ret != 0)
763 		uart_unregister_driver(&lqasc_reg);
764 
765 	return ret;
766 }
767 
768 module_init(init_lqasc);
769 
770 MODULE_DESCRIPTION("Lantiq serial port driver");
771 MODULE_LICENSE("GPL");
772