xref: /openbmc/linux/drivers/tty/serial/lantiq.c (revision 92a19f9cec9a80ad93c06e115822deb729e2c6ad)
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 void
158 lqasc_enable_ms(struct uart_port *port)
159 {
160 }
161 
162 static int
163 lqasc_rx_chars(struct uart_port *port)
164 {
165 	struct tty_port *tport = &port->state->port;
166 	struct tty_struct *tty = tty_port_tty_get(tport);
167 	unsigned int ch = 0, rsr = 0, fifocnt;
168 
169 	if (!tty) {
170 		dev_dbg(port->dev, "%s:tty is busy now", __func__);
171 		return -EBUSY;
172 	}
173 	fifocnt =
174 		ltq_r32(port->membase + LTQ_ASC_FSTAT) & ASCFSTAT_RXFFLMASK;
175 	while (fifocnt--) {
176 		u8 flag = TTY_NORMAL;
177 		ch = ltq_r8(port->membase + LTQ_ASC_RBUF);
178 		rsr = (ltq_r32(port->membase + LTQ_ASC_STATE)
179 			& ASCSTATE_ANY) | UART_DUMMY_UER_RX;
180 		tty_flip_buffer_push(tty);
181 		port->icount.rx++;
182 
183 		/*
184 		 * Note that the error handling code is
185 		 * out of the main execution path
186 		 */
187 		if (rsr & ASCSTATE_ANY) {
188 			if (rsr & ASCSTATE_PE) {
189 				port->icount.parity++;
190 				ltq_w32_mask(0, ASCWHBSTATE_CLRPE,
191 					port->membase + LTQ_ASC_WHBSTATE);
192 			} else if (rsr & ASCSTATE_FE) {
193 				port->icount.frame++;
194 				ltq_w32_mask(0, ASCWHBSTATE_CLRFE,
195 					port->membase + LTQ_ASC_WHBSTATE);
196 			}
197 			if (rsr & ASCSTATE_ROE) {
198 				port->icount.overrun++;
199 				ltq_w32_mask(0, ASCWHBSTATE_CLRROE,
200 					port->membase + LTQ_ASC_WHBSTATE);
201 			}
202 
203 			rsr &= port->read_status_mask;
204 
205 			if (rsr & ASCSTATE_PE)
206 				flag = TTY_PARITY;
207 			else if (rsr & ASCSTATE_FE)
208 				flag = TTY_FRAME;
209 		}
210 
211 		if ((rsr & port->ignore_status_mask) == 0)
212 			tty_insert_flip_char(tport, ch, flag);
213 
214 		if (rsr & ASCSTATE_ROE)
215 			/*
216 			 * Overrun is special, since it's reported
217 			 * immediately, and doesn't affect the current
218 			 * character
219 			 */
220 			tty_insert_flip_char(tport, 0, TTY_OVERRUN);
221 	}
222 	if (ch != 0)
223 		tty_flip_buffer_push(tty);
224 	tty_kref_put(tty);
225 	return 0;
226 }
227 
228 static void
229 lqasc_tx_chars(struct uart_port *port)
230 {
231 	struct circ_buf *xmit = &port->state->xmit;
232 	if (uart_tx_stopped(port)) {
233 		lqasc_stop_tx(port);
234 		return;
235 	}
236 
237 	while (((ltq_r32(port->membase + LTQ_ASC_FSTAT) &
238 		ASCFSTAT_TXFREEMASK) >> ASCFSTAT_TXFREEOFF) != 0) {
239 		if (port->x_char) {
240 			ltq_w8(port->x_char, port->membase + LTQ_ASC_TBUF);
241 			port->icount.tx++;
242 			port->x_char = 0;
243 			continue;
244 		}
245 
246 		if (uart_circ_empty(xmit))
247 			break;
248 
249 		ltq_w8(port->state->xmit.buf[port->state->xmit.tail],
250 			port->membase + LTQ_ASC_TBUF);
251 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
252 		port->icount.tx++;
253 	}
254 
255 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
256 		uart_write_wakeup(port);
257 }
258 
259 static irqreturn_t
260 lqasc_tx_int(int irq, void *_port)
261 {
262 	unsigned long flags;
263 	struct uart_port *port = (struct uart_port *)_port;
264 	spin_lock_irqsave(&ltq_asc_lock, flags);
265 	ltq_w32(ASC_IRNCR_TIR, port->membase + LTQ_ASC_IRNCR);
266 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
267 	lqasc_start_tx(port);
268 	return IRQ_HANDLED;
269 }
270 
271 static irqreturn_t
272 lqasc_err_int(int irq, void *_port)
273 {
274 	unsigned long flags;
275 	struct uart_port *port = (struct uart_port *)_port;
276 	spin_lock_irqsave(&ltq_asc_lock, flags);
277 	/* clear any pending interrupts */
278 	ltq_w32_mask(0, ASCWHBSTATE_CLRPE | ASCWHBSTATE_CLRFE |
279 		ASCWHBSTATE_CLRROE, port->membase + LTQ_ASC_WHBSTATE);
280 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
281 	return IRQ_HANDLED;
282 }
283 
284 static irqreturn_t
285 lqasc_rx_int(int irq, void *_port)
286 {
287 	unsigned long flags;
288 	struct uart_port *port = (struct uart_port *)_port;
289 	spin_lock_irqsave(&ltq_asc_lock, flags);
290 	ltq_w32(ASC_IRNCR_RIR, port->membase + LTQ_ASC_IRNCR);
291 	lqasc_rx_chars(port);
292 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
293 	return IRQ_HANDLED;
294 }
295 
296 static unsigned int
297 lqasc_tx_empty(struct uart_port *port)
298 {
299 	int status;
300 	status = ltq_r32(port->membase + LTQ_ASC_FSTAT) & ASCFSTAT_TXFFLMASK;
301 	return status ? 0 : TIOCSER_TEMT;
302 }
303 
304 static unsigned int
305 lqasc_get_mctrl(struct uart_port *port)
306 {
307 	return TIOCM_CTS | TIOCM_CAR | TIOCM_DSR;
308 }
309 
310 static void
311 lqasc_set_mctrl(struct uart_port *port, u_int mctrl)
312 {
313 }
314 
315 static void
316 lqasc_break_ctl(struct uart_port *port, int break_state)
317 {
318 }
319 
320 static int
321 lqasc_startup(struct uart_port *port)
322 {
323 	struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
324 	int retval;
325 
326 	if (ltq_port->clk)
327 		clk_enable(ltq_port->clk);
328 	port->uartclk = clk_get_rate(ltq_port->fpiclk);
329 
330 	ltq_w32_mask(ASCCLC_DISS | ASCCLC_RMCMASK, (1 << ASCCLC_RMCOFFSET),
331 		port->membase + LTQ_ASC_CLC);
332 
333 	ltq_w32(0, port->membase + LTQ_ASC_PISEL);
334 	ltq_w32(
335 		((TXFIFO_FL << ASCTXFCON_TXFITLOFF) & ASCTXFCON_TXFITLMASK) |
336 		ASCTXFCON_TXFEN | ASCTXFCON_TXFFLU,
337 		port->membase + LTQ_ASC_TXFCON);
338 	ltq_w32(
339 		((RXFIFO_FL << ASCRXFCON_RXFITLOFF) & ASCRXFCON_RXFITLMASK)
340 		| ASCRXFCON_RXFEN | ASCRXFCON_RXFFLU,
341 		port->membase + LTQ_ASC_RXFCON);
342 	/* make sure other settings are written to hardware before
343 	 * setting enable bits
344 	 */
345 	wmb();
346 	ltq_w32_mask(0, ASCCON_M_8ASYNC | ASCCON_FEN | ASCCON_TOEN |
347 		ASCCON_ROEN, port->membase + LTQ_ASC_CON);
348 
349 	retval = request_irq(ltq_port->tx_irq, lqasc_tx_int,
350 		0, "asc_tx", port);
351 	if (retval) {
352 		pr_err("failed to request lqasc_tx_int\n");
353 		return retval;
354 	}
355 
356 	retval = request_irq(ltq_port->rx_irq, lqasc_rx_int,
357 		0, "asc_rx", port);
358 	if (retval) {
359 		pr_err("failed to request lqasc_rx_int\n");
360 		goto err1;
361 	}
362 
363 	retval = request_irq(ltq_port->err_irq, lqasc_err_int,
364 		0, "asc_err", port);
365 	if (retval) {
366 		pr_err("failed to request lqasc_err_int\n");
367 		goto err2;
368 	}
369 
370 	ltq_w32(ASC_IRNREN_RX | ASC_IRNREN_ERR | ASC_IRNREN_TX,
371 		port->membase + LTQ_ASC_IRNREN);
372 	return 0;
373 
374 err2:
375 	free_irq(ltq_port->rx_irq, port);
376 err1:
377 	free_irq(ltq_port->tx_irq, port);
378 	return retval;
379 }
380 
381 static void
382 lqasc_shutdown(struct uart_port *port)
383 {
384 	struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
385 	free_irq(ltq_port->tx_irq, port);
386 	free_irq(ltq_port->rx_irq, port);
387 	free_irq(ltq_port->err_irq, port);
388 
389 	ltq_w32(0, port->membase + LTQ_ASC_CON);
390 	ltq_w32_mask(ASCRXFCON_RXFEN, ASCRXFCON_RXFFLU,
391 		port->membase + LTQ_ASC_RXFCON);
392 	ltq_w32_mask(ASCTXFCON_TXFEN, ASCTXFCON_TXFFLU,
393 		port->membase + LTQ_ASC_TXFCON);
394 	if (ltq_port->clk)
395 		clk_disable(ltq_port->clk);
396 }
397 
398 static void
399 lqasc_set_termios(struct uart_port *port,
400 	struct ktermios *new, struct ktermios *old)
401 {
402 	unsigned int cflag;
403 	unsigned int iflag;
404 	unsigned int divisor;
405 	unsigned int baud;
406 	unsigned int con = 0;
407 	unsigned long flags;
408 
409 	cflag = new->c_cflag;
410 	iflag = new->c_iflag;
411 
412 	switch (cflag & CSIZE) {
413 	case CS7:
414 		con = ASCCON_M_7ASYNC;
415 		break;
416 
417 	case CS5:
418 	case CS6:
419 	default:
420 		new->c_cflag &= ~ CSIZE;
421 		new->c_cflag |= CS8;
422 		con = ASCCON_M_8ASYNC;
423 		break;
424 	}
425 
426 	cflag &= ~CMSPAR; /* Mark/Space parity is not supported */
427 
428 	if (cflag & CSTOPB)
429 		con |= ASCCON_STP;
430 
431 	if (cflag & PARENB) {
432 		if (!(cflag & PARODD))
433 			con &= ~ASCCON_ODD;
434 		else
435 			con |= ASCCON_ODD;
436 	}
437 
438 	port->read_status_mask = ASCSTATE_ROE;
439 	if (iflag & INPCK)
440 		port->read_status_mask |= ASCSTATE_FE | ASCSTATE_PE;
441 
442 	port->ignore_status_mask = 0;
443 	if (iflag & IGNPAR)
444 		port->ignore_status_mask |= ASCSTATE_FE | ASCSTATE_PE;
445 
446 	if (iflag & IGNBRK) {
447 		/*
448 		 * If we're ignoring parity and break indicators,
449 		 * ignore overruns too (for real raw support).
450 		 */
451 		if (iflag & IGNPAR)
452 			port->ignore_status_mask |= ASCSTATE_ROE;
453 	}
454 
455 	if ((cflag & CREAD) == 0)
456 		port->ignore_status_mask |= UART_DUMMY_UER_RX;
457 
458 	/* set error signals  - framing, parity  and overrun, enable receiver */
459 	con |= ASCCON_FEN | ASCCON_TOEN | ASCCON_ROEN;
460 
461 	spin_lock_irqsave(&ltq_asc_lock, flags);
462 
463 	/* set up CON */
464 	ltq_w32_mask(0, con, port->membase + LTQ_ASC_CON);
465 
466 	/* Set baud rate - take a divider of 2 into account */
467 	baud = uart_get_baud_rate(port, new, old, 0, port->uartclk / 16);
468 	divisor = uart_get_divisor(port, baud);
469 	divisor = divisor / 2 - 1;
470 
471 	/* disable the baudrate generator */
472 	ltq_w32_mask(ASCCON_R, 0, port->membase + LTQ_ASC_CON);
473 
474 	/* make sure the fractional divider is off */
475 	ltq_w32_mask(ASCCON_FDE, 0, port->membase + LTQ_ASC_CON);
476 
477 	/* set up to use divisor of 2 */
478 	ltq_w32_mask(ASCCON_BRS, 0, port->membase + LTQ_ASC_CON);
479 
480 	/* now we can write the new baudrate into the register */
481 	ltq_w32(divisor, port->membase + LTQ_ASC_BG);
482 
483 	/* turn the baudrate generator back on */
484 	ltq_w32_mask(0, ASCCON_R, port->membase + LTQ_ASC_CON);
485 
486 	/* enable rx */
487 	ltq_w32(ASCWHBSTATE_SETREN, port->membase + LTQ_ASC_WHBSTATE);
488 
489 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
490 
491 	/* Don't rewrite B0 */
492 	if (tty_termios_baud_rate(new))
493 		tty_termios_encode_baud_rate(new, baud, baud);
494 
495 	uart_update_timeout(port, cflag, baud);
496 }
497 
498 static const char*
499 lqasc_type(struct uart_port *port)
500 {
501 	if (port->type == PORT_LTQ_ASC)
502 		return DRVNAME;
503 	else
504 		return NULL;
505 }
506 
507 static void
508 lqasc_release_port(struct uart_port *port)
509 {
510 	if (port->flags & UPF_IOREMAP) {
511 		iounmap(port->membase);
512 		port->membase = NULL;
513 	}
514 }
515 
516 static int
517 lqasc_request_port(struct uart_port *port)
518 {
519 	struct platform_device *pdev = to_platform_device(port->dev);
520 	struct resource *res;
521 	int size;
522 
523 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
524 	if (!res) {
525 		dev_err(&pdev->dev, "cannot obtain I/O memory region");
526 		return -ENODEV;
527 	}
528 	size = resource_size(res);
529 
530 	res = devm_request_mem_region(&pdev->dev, res->start,
531 		size, dev_name(&pdev->dev));
532 	if (!res) {
533 		dev_err(&pdev->dev, "cannot request I/O memory region");
534 		return -EBUSY;
535 	}
536 
537 	if (port->flags & UPF_IOREMAP) {
538 		port->membase = devm_ioremap_nocache(&pdev->dev,
539 			port->mapbase, size);
540 		if (port->membase == NULL)
541 			return -ENOMEM;
542 	}
543 	return 0;
544 }
545 
546 static void
547 lqasc_config_port(struct uart_port *port, int flags)
548 {
549 	if (flags & UART_CONFIG_TYPE) {
550 		port->type = PORT_LTQ_ASC;
551 		lqasc_request_port(port);
552 	}
553 }
554 
555 static int
556 lqasc_verify_port(struct uart_port *port,
557 	struct serial_struct *ser)
558 {
559 	int ret = 0;
560 	if (ser->type != PORT_UNKNOWN && ser->type != PORT_LTQ_ASC)
561 		ret = -EINVAL;
562 	if (ser->irq < 0 || ser->irq >= NR_IRQS)
563 		ret = -EINVAL;
564 	if (ser->baud_base < 9600)
565 		ret = -EINVAL;
566 	return ret;
567 }
568 
569 static struct uart_ops lqasc_pops = {
570 	.tx_empty =	lqasc_tx_empty,
571 	.set_mctrl =	lqasc_set_mctrl,
572 	.get_mctrl =	lqasc_get_mctrl,
573 	.stop_tx =	lqasc_stop_tx,
574 	.start_tx =	lqasc_start_tx,
575 	.stop_rx =	lqasc_stop_rx,
576 	.enable_ms =	lqasc_enable_ms,
577 	.break_ctl =	lqasc_break_ctl,
578 	.startup =	lqasc_startup,
579 	.shutdown =	lqasc_shutdown,
580 	.set_termios =	lqasc_set_termios,
581 	.type =		lqasc_type,
582 	.release_port =	lqasc_release_port,
583 	.request_port =	lqasc_request_port,
584 	.config_port =	lqasc_config_port,
585 	.verify_port =	lqasc_verify_port,
586 };
587 
588 static void
589 lqasc_console_putchar(struct uart_port *port, int ch)
590 {
591 	int fifofree;
592 
593 	if (!port->membase)
594 		return;
595 
596 	do {
597 		fifofree = (ltq_r32(port->membase + LTQ_ASC_FSTAT)
598 			& ASCFSTAT_TXFREEMASK) >> ASCFSTAT_TXFREEOFF;
599 	} while (fifofree == 0);
600 	ltq_w8(ch, port->membase + LTQ_ASC_TBUF);
601 }
602 
603 
604 static void
605 lqasc_console_write(struct console *co, const char *s, u_int count)
606 {
607 	struct ltq_uart_port *ltq_port;
608 	struct uart_port *port;
609 	unsigned long flags;
610 
611 	if (co->index >= MAXPORTS)
612 		return;
613 
614 	ltq_port = lqasc_port[co->index];
615 	if (!ltq_port)
616 		return;
617 
618 	port = &ltq_port->port;
619 
620 	spin_lock_irqsave(&ltq_asc_lock, flags);
621 	uart_console_write(port, s, count, lqasc_console_putchar);
622 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
623 }
624 
625 static int __init
626 lqasc_console_setup(struct console *co, char *options)
627 {
628 	struct ltq_uart_port *ltq_port;
629 	struct uart_port *port;
630 	int baud = 115200;
631 	int bits = 8;
632 	int parity = 'n';
633 	int flow = 'n';
634 
635 	if (co->index >= MAXPORTS)
636 		return -ENODEV;
637 
638 	ltq_port = lqasc_port[co->index];
639 	if (!ltq_port)
640 		return -ENODEV;
641 
642 	port = &ltq_port->port;
643 
644 	port->uartclk = clk_get_rate(ltq_port->fpiclk);
645 
646 	if (options)
647 		uart_parse_options(options, &baud, &parity, &bits, &flow);
648 	return uart_set_options(port, co, baud, parity, bits, flow);
649 }
650 
651 static struct console lqasc_console = {
652 	.name =		"ttyLTQ",
653 	.write =	lqasc_console_write,
654 	.device =	uart_console_device,
655 	.setup =	lqasc_console_setup,
656 	.flags =	CON_PRINTBUFFER,
657 	.index =	-1,
658 	.data =		&lqasc_reg,
659 };
660 
661 static int __init
662 lqasc_console_init(void)
663 {
664 	register_console(&lqasc_console);
665 	return 0;
666 }
667 console_initcall(lqasc_console_init);
668 
669 static struct uart_driver lqasc_reg = {
670 	.owner =	THIS_MODULE,
671 	.driver_name =	DRVNAME,
672 	.dev_name =	"ttyLTQ",
673 	.major =	0,
674 	.minor =	0,
675 	.nr =		MAXPORTS,
676 	.cons =		&lqasc_console,
677 };
678 
679 static int __init
680 lqasc_probe(struct platform_device *pdev)
681 {
682 	struct device_node *node = pdev->dev.of_node;
683 	struct ltq_uart_port *ltq_port;
684 	struct uart_port *port;
685 	struct resource *mmres, irqres[3];
686 	int line = 0;
687 	int ret;
688 
689 	mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
690 	ret = of_irq_to_resource_table(node, irqres, 3);
691 	if (!mmres || (ret != 3)) {
692 		dev_err(&pdev->dev,
693 			"failed to get memory/irq for serial port\n");
694 		return -ENODEV;
695 	}
696 
697 	/* check if this is the console port */
698 	if (mmres->start != CPHYSADDR(LTQ_EARLY_ASC))
699 		line = 1;
700 
701 	if (lqasc_port[line]) {
702 		dev_err(&pdev->dev, "port %d already allocated\n", line);
703 		return -EBUSY;
704 	}
705 
706 	ltq_port = devm_kzalloc(&pdev->dev, sizeof(struct ltq_uart_port),
707 			GFP_KERNEL);
708 	if (!ltq_port)
709 		return -ENOMEM;
710 
711 	port = &ltq_port->port;
712 
713 	port->iotype	= SERIAL_IO_MEM;
714 	port->flags	= ASYNC_BOOT_AUTOCONF | UPF_IOREMAP;
715 	port->ops	= &lqasc_pops;
716 	port->fifosize	= 16;
717 	port->type	= PORT_LTQ_ASC,
718 	port->line	= line;
719 	port->dev	= &pdev->dev;
720 	/* unused, just to be backward-compatible */
721 	port->irq	= irqres[0].start;
722 	port->mapbase	= mmres->start;
723 
724 	ltq_port->fpiclk = clk_get_fpi();
725 	if (IS_ERR(ltq_port->fpiclk)) {
726 		pr_err("failed to get fpi clk\n");
727 		return -ENOENT;
728 	}
729 
730 	/* not all asc ports have clock gates, lets ignore the return code */
731 	ltq_port->clk = clk_get(&pdev->dev, NULL);
732 
733 	ltq_port->tx_irq = irqres[0].start;
734 	ltq_port->rx_irq = irqres[1].start;
735 	ltq_port->err_irq = irqres[2].start;
736 
737 	lqasc_port[line] = ltq_port;
738 	platform_set_drvdata(pdev, ltq_port);
739 
740 	ret = uart_add_one_port(&lqasc_reg, port);
741 
742 	return ret;
743 }
744 
745 static const struct of_device_id ltq_asc_match[] = {
746 	{ .compatible = DRVNAME },
747 	{},
748 };
749 MODULE_DEVICE_TABLE(of, ltq_asc_match);
750 
751 static struct platform_driver lqasc_driver = {
752 	.driver		= {
753 		.name	= DRVNAME,
754 		.owner	= THIS_MODULE,
755 		.of_match_table = ltq_asc_match,
756 	},
757 };
758 
759 int __init
760 init_lqasc(void)
761 {
762 	int ret;
763 
764 	ret = uart_register_driver(&lqasc_reg);
765 	if (ret != 0)
766 		return ret;
767 
768 	ret = platform_driver_probe(&lqasc_driver, lqasc_probe);
769 	if (ret != 0)
770 		uart_unregister_driver(&lqasc_reg);
771 
772 	return ret;
773 }
774 
775 module_init(init_lqasc);
776 
777 MODULE_DESCRIPTION("Lantiq serial port driver");
778 MODULE_LICENSE("GPL");
779