xref: /openbmc/linux/drivers/tty/serial/lantiq.c (revision ba61bb17) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
4  *
5  * Copyright (C) 2004 Infineon IFAP DC COM CPE
6  * Copyright (C) 2007 Felix Fietkau <nbd@openwrt.org>
7  * Copyright (C) 2007 John Crispin <john@phrozen.org>
8  * Copyright (C) 2010 Thomas Langer, <thomas.langer@lantiq.com>
9  */
10 
11 #include <linux/slab.h>
12 #include <linux/ioport.h>
13 #include <linux/init.h>
14 #include <linux/console.h>
15 #include <linux/sysrq.h>
16 #include <linux/device.h>
17 #include <linux/tty.h>
18 #include <linux/tty_flip.h>
19 #include <linux/serial_core.h>
20 #include <linux/serial.h>
21 #include <linux/of_platform.h>
22 #include <linux/of_address.h>
23 #include <linux/of_irq.h>
24 #include <linux/io.h>
25 #include <linux/clk.h>
26 #include <linux/gpio.h>
27 
28 #include <lantiq_soc.h>
29 
30 #define PORT_LTQ_ASC		111
31 #define MAXPORTS		2
32 #define UART_DUMMY_UER_RX	1
33 #define DRVNAME			"lantiq,asc"
34 #ifdef __BIG_ENDIAN
35 #define LTQ_ASC_TBUF		(0x0020 + 3)
36 #define LTQ_ASC_RBUF		(0x0024 + 3)
37 #else
38 #define LTQ_ASC_TBUF		0x0020
39 #define LTQ_ASC_RBUF		0x0024
40 #endif
41 #define LTQ_ASC_FSTAT		0x0048
42 #define LTQ_ASC_WHBSTATE	0x0018
43 #define LTQ_ASC_STATE		0x0014
44 #define LTQ_ASC_IRNCR		0x00F8
45 #define LTQ_ASC_CLC		0x0000
46 #define LTQ_ASC_ID		0x0008
47 #define LTQ_ASC_PISEL		0x0004
48 #define LTQ_ASC_TXFCON		0x0044
49 #define LTQ_ASC_RXFCON		0x0040
50 #define LTQ_ASC_CON		0x0010
51 #define LTQ_ASC_BG		0x0050
52 #define LTQ_ASC_IRNREN		0x00F4
53 
54 #define ASC_IRNREN_TX		0x1
55 #define ASC_IRNREN_RX		0x2
56 #define ASC_IRNREN_ERR		0x4
57 #define ASC_IRNREN_TX_BUF	0x8
58 #define ASC_IRNCR_TIR		0x1
59 #define ASC_IRNCR_RIR		0x2
60 #define ASC_IRNCR_EIR		0x4
61 
62 #define ASCOPT_CSIZE		0x3
63 #define TXFIFO_FL		1
64 #define RXFIFO_FL		1
65 #define ASCCLC_DISS		0x2
66 #define ASCCLC_RMCMASK		0x0000FF00
67 #define ASCCLC_RMCOFFSET	8
68 #define ASCCON_M_8ASYNC		0x0
69 #define ASCCON_M_7ASYNC		0x2
70 #define ASCCON_ODD		0x00000020
71 #define ASCCON_STP		0x00000080
72 #define ASCCON_BRS		0x00000100
73 #define ASCCON_FDE		0x00000200
74 #define ASCCON_R		0x00008000
75 #define ASCCON_FEN		0x00020000
76 #define ASCCON_ROEN		0x00080000
77 #define ASCCON_TOEN		0x00100000
78 #define ASCSTATE_PE		0x00010000
79 #define ASCSTATE_FE		0x00020000
80 #define ASCSTATE_ROE		0x00080000
81 #define ASCSTATE_ANY		(ASCSTATE_ROE|ASCSTATE_PE|ASCSTATE_FE)
82 #define ASCWHBSTATE_CLRREN	0x00000001
83 #define ASCWHBSTATE_SETREN	0x00000002
84 #define ASCWHBSTATE_CLRPE	0x00000004
85 #define ASCWHBSTATE_CLRFE	0x00000008
86 #define ASCWHBSTATE_CLRROE	0x00000020
87 #define ASCTXFCON_TXFEN		0x0001
88 #define ASCTXFCON_TXFFLU	0x0002
89 #define ASCTXFCON_TXFITLMASK	0x3F00
90 #define ASCTXFCON_TXFITLOFF	8
91 #define ASCRXFCON_RXFEN		0x0001
92 #define ASCRXFCON_RXFFLU	0x0002
93 #define ASCRXFCON_RXFITLMASK	0x3F00
94 #define ASCRXFCON_RXFITLOFF	8
95 #define ASCFSTAT_RXFFLMASK	0x003F
96 #define ASCFSTAT_TXFFLMASK	0x3F00
97 #define ASCFSTAT_TXFREEMASK	0x3F000000
98 #define ASCFSTAT_TXFREEOFF	24
99 
100 static void lqasc_tx_chars(struct uart_port *port);
101 static struct ltq_uart_port *lqasc_port[MAXPORTS];
102 static struct uart_driver lqasc_reg;
103 static DEFINE_SPINLOCK(ltq_asc_lock);
104 
105 struct ltq_uart_port {
106 	struct uart_port	port;
107 	/* clock used to derive divider */
108 	struct clk		*fpiclk;
109 	/* clock gating of the ASC core */
110 	struct clk		*clk;
111 	unsigned int		tx_irq;
112 	unsigned int		rx_irq;
113 	unsigned int		err_irq;
114 };
115 
116 static inline struct
117 ltq_uart_port *to_ltq_uart_port(struct uart_port *port)
118 {
119 	return container_of(port, struct ltq_uart_port, port);
120 }
121 
122 static void
123 lqasc_stop_tx(struct uart_port *port)
124 {
125 	return;
126 }
127 
128 static void
129 lqasc_start_tx(struct uart_port *port)
130 {
131 	unsigned long flags;
132 	spin_lock_irqsave(&ltq_asc_lock, flags);
133 	lqasc_tx_chars(port);
134 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
135 	return;
136 }
137 
138 static void
139 lqasc_stop_rx(struct uart_port *port)
140 {
141 	ltq_w32(ASCWHBSTATE_CLRREN, port->membase + LTQ_ASC_WHBSTATE);
142 }
143 
144 static int
145 lqasc_rx_chars(struct uart_port *port)
146 {
147 	struct tty_port *tport = &port->state->port;
148 	unsigned int ch = 0, rsr = 0, fifocnt;
149 
150 	fifocnt = ltq_r32(port->membase + LTQ_ASC_FSTAT) & ASCFSTAT_RXFFLMASK;
151 	while (fifocnt--) {
152 		u8 flag = TTY_NORMAL;
153 		ch = ltq_r8(port->membase + LTQ_ASC_RBUF);
154 		rsr = (ltq_r32(port->membase + LTQ_ASC_STATE)
155 			& ASCSTATE_ANY) | UART_DUMMY_UER_RX;
156 		tty_flip_buffer_push(tport);
157 		port->icount.rx++;
158 
159 		/*
160 		 * Note that the error handling code is
161 		 * out of the main execution path
162 		 */
163 		if (rsr & ASCSTATE_ANY) {
164 			if (rsr & ASCSTATE_PE) {
165 				port->icount.parity++;
166 				ltq_w32_mask(0, ASCWHBSTATE_CLRPE,
167 					port->membase + LTQ_ASC_WHBSTATE);
168 			} else if (rsr & ASCSTATE_FE) {
169 				port->icount.frame++;
170 				ltq_w32_mask(0, ASCWHBSTATE_CLRFE,
171 					port->membase + LTQ_ASC_WHBSTATE);
172 			}
173 			if (rsr & ASCSTATE_ROE) {
174 				port->icount.overrun++;
175 				ltq_w32_mask(0, ASCWHBSTATE_CLRROE,
176 					port->membase + LTQ_ASC_WHBSTATE);
177 			}
178 
179 			rsr &= port->read_status_mask;
180 
181 			if (rsr & ASCSTATE_PE)
182 				flag = TTY_PARITY;
183 			else if (rsr & ASCSTATE_FE)
184 				flag = TTY_FRAME;
185 		}
186 
187 		if ((rsr & port->ignore_status_mask) == 0)
188 			tty_insert_flip_char(tport, ch, flag);
189 
190 		if (rsr & ASCSTATE_ROE)
191 			/*
192 			 * Overrun is special, since it's reported
193 			 * immediately, and doesn't affect the current
194 			 * character
195 			 */
196 			tty_insert_flip_char(tport, 0, TTY_OVERRUN);
197 	}
198 
199 	if (ch != 0)
200 		tty_flip_buffer_push(tport);
201 
202 	return 0;
203 }
204 
205 static void
206 lqasc_tx_chars(struct uart_port *port)
207 {
208 	struct circ_buf *xmit = &port->state->xmit;
209 	if (uart_tx_stopped(port)) {
210 		lqasc_stop_tx(port);
211 		return;
212 	}
213 
214 	while (((ltq_r32(port->membase + LTQ_ASC_FSTAT) &
215 		ASCFSTAT_TXFREEMASK) >> ASCFSTAT_TXFREEOFF) != 0) {
216 		if (port->x_char) {
217 			ltq_w8(port->x_char, port->membase + LTQ_ASC_TBUF);
218 			port->icount.tx++;
219 			port->x_char = 0;
220 			continue;
221 		}
222 
223 		if (uart_circ_empty(xmit))
224 			break;
225 
226 		ltq_w8(port->state->xmit.buf[port->state->xmit.tail],
227 			port->membase + LTQ_ASC_TBUF);
228 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
229 		port->icount.tx++;
230 	}
231 
232 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
233 		uart_write_wakeup(port);
234 }
235 
236 static irqreturn_t
237 lqasc_tx_int(int irq, void *_port)
238 {
239 	unsigned long flags;
240 	struct uart_port *port = (struct uart_port *)_port;
241 	spin_lock_irqsave(&ltq_asc_lock, flags);
242 	ltq_w32(ASC_IRNCR_TIR, port->membase + LTQ_ASC_IRNCR);
243 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
244 	lqasc_start_tx(port);
245 	return IRQ_HANDLED;
246 }
247 
248 static irqreturn_t
249 lqasc_err_int(int irq, void *_port)
250 {
251 	unsigned long flags;
252 	struct uart_port *port = (struct uart_port *)_port;
253 	spin_lock_irqsave(&ltq_asc_lock, flags);
254 	/* clear any pending interrupts */
255 	ltq_w32_mask(0, ASCWHBSTATE_CLRPE | ASCWHBSTATE_CLRFE |
256 		ASCWHBSTATE_CLRROE, port->membase + LTQ_ASC_WHBSTATE);
257 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
258 	return IRQ_HANDLED;
259 }
260 
261 static irqreturn_t
262 lqasc_rx_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 	ltq_w32(ASC_IRNCR_RIR, port->membase + LTQ_ASC_IRNCR);
268 	lqasc_rx_chars(port);
269 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
270 	return IRQ_HANDLED;
271 }
272 
273 static unsigned int
274 lqasc_tx_empty(struct uart_port *port)
275 {
276 	int status;
277 	status = ltq_r32(port->membase + LTQ_ASC_FSTAT) & ASCFSTAT_TXFFLMASK;
278 	return status ? 0 : TIOCSER_TEMT;
279 }
280 
281 static unsigned int
282 lqasc_get_mctrl(struct uart_port *port)
283 {
284 	return TIOCM_CTS | TIOCM_CAR | TIOCM_DSR;
285 }
286 
287 static void
288 lqasc_set_mctrl(struct uart_port *port, u_int mctrl)
289 {
290 }
291 
292 static void
293 lqasc_break_ctl(struct uart_port *port, int break_state)
294 {
295 }
296 
297 static int
298 lqasc_startup(struct uart_port *port)
299 {
300 	struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
301 	int retval;
302 
303 	if (!IS_ERR(ltq_port->clk))
304 		clk_enable(ltq_port->clk);
305 	port->uartclk = clk_get_rate(ltq_port->fpiclk);
306 
307 	ltq_w32_mask(ASCCLC_DISS | ASCCLC_RMCMASK, (1 << ASCCLC_RMCOFFSET),
308 		port->membase + LTQ_ASC_CLC);
309 
310 	ltq_w32(0, port->membase + LTQ_ASC_PISEL);
311 	ltq_w32(
312 		((TXFIFO_FL << ASCTXFCON_TXFITLOFF) & ASCTXFCON_TXFITLMASK) |
313 		ASCTXFCON_TXFEN | ASCTXFCON_TXFFLU,
314 		port->membase + LTQ_ASC_TXFCON);
315 	ltq_w32(
316 		((RXFIFO_FL << ASCRXFCON_RXFITLOFF) & ASCRXFCON_RXFITLMASK)
317 		| ASCRXFCON_RXFEN | ASCRXFCON_RXFFLU,
318 		port->membase + LTQ_ASC_RXFCON);
319 	/* make sure other settings are written to hardware before
320 	 * setting enable bits
321 	 */
322 	wmb();
323 	ltq_w32_mask(0, ASCCON_M_8ASYNC | ASCCON_FEN | ASCCON_TOEN |
324 		ASCCON_ROEN, port->membase + LTQ_ASC_CON);
325 
326 	retval = request_irq(ltq_port->tx_irq, lqasc_tx_int,
327 		0, "asc_tx", port);
328 	if (retval) {
329 		pr_err("failed to request lqasc_tx_int\n");
330 		return retval;
331 	}
332 
333 	retval = request_irq(ltq_port->rx_irq, lqasc_rx_int,
334 		0, "asc_rx", port);
335 	if (retval) {
336 		pr_err("failed to request lqasc_rx_int\n");
337 		goto err1;
338 	}
339 
340 	retval = request_irq(ltq_port->err_irq, lqasc_err_int,
341 		0, "asc_err", port);
342 	if (retval) {
343 		pr_err("failed to request lqasc_err_int\n");
344 		goto err2;
345 	}
346 
347 	ltq_w32(ASC_IRNREN_RX | ASC_IRNREN_ERR | ASC_IRNREN_TX,
348 		port->membase + LTQ_ASC_IRNREN);
349 	return 0;
350 
351 err2:
352 	free_irq(ltq_port->rx_irq, port);
353 err1:
354 	free_irq(ltq_port->tx_irq, port);
355 	return retval;
356 }
357 
358 static void
359 lqasc_shutdown(struct uart_port *port)
360 {
361 	struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
362 	free_irq(ltq_port->tx_irq, port);
363 	free_irq(ltq_port->rx_irq, port);
364 	free_irq(ltq_port->err_irq, port);
365 
366 	ltq_w32(0, port->membase + LTQ_ASC_CON);
367 	ltq_w32_mask(ASCRXFCON_RXFEN, ASCRXFCON_RXFFLU,
368 		port->membase + LTQ_ASC_RXFCON);
369 	ltq_w32_mask(ASCTXFCON_TXFEN, ASCTXFCON_TXFFLU,
370 		port->membase + LTQ_ASC_TXFCON);
371 	if (!IS_ERR(ltq_port->clk))
372 		clk_disable(ltq_port->clk);
373 }
374 
375 static void
376 lqasc_set_termios(struct uart_port *port,
377 	struct ktermios *new, struct ktermios *old)
378 {
379 	unsigned int cflag;
380 	unsigned int iflag;
381 	unsigned int divisor;
382 	unsigned int baud;
383 	unsigned int con = 0;
384 	unsigned long flags;
385 
386 	cflag = new->c_cflag;
387 	iflag = new->c_iflag;
388 
389 	switch (cflag & CSIZE) {
390 	case CS7:
391 		con = ASCCON_M_7ASYNC;
392 		break;
393 
394 	case CS5:
395 	case CS6:
396 	default:
397 		new->c_cflag &= ~ CSIZE;
398 		new->c_cflag |= CS8;
399 		con = ASCCON_M_8ASYNC;
400 		break;
401 	}
402 
403 	cflag &= ~CMSPAR; /* Mark/Space parity is not supported */
404 
405 	if (cflag & CSTOPB)
406 		con |= ASCCON_STP;
407 
408 	if (cflag & PARENB) {
409 		if (!(cflag & PARODD))
410 			con &= ~ASCCON_ODD;
411 		else
412 			con |= ASCCON_ODD;
413 	}
414 
415 	port->read_status_mask = ASCSTATE_ROE;
416 	if (iflag & INPCK)
417 		port->read_status_mask |= ASCSTATE_FE | ASCSTATE_PE;
418 
419 	port->ignore_status_mask = 0;
420 	if (iflag & IGNPAR)
421 		port->ignore_status_mask |= ASCSTATE_FE | ASCSTATE_PE;
422 
423 	if (iflag & IGNBRK) {
424 		/*
425 		 * If we're ignoring parity and break indicators,
426 		 * ignore overruns too (for real raw support).
427 		 */
428 		if (iflag & IGNPAR)
429 			port->ignore_status_mask |= ASCSTATE_ROE;
430 	}
431 
432 	if ((cflag & CREAD) == 0)
433 		port->ignore_status_mask |= UART_DUMMY_UER_RX;
434 
435 	/* set error signals  - framing, parity  and overrun, enable receiver */
436 	con |= ASCCON_FEN | ASCCON_TOEN | ASCCON_ROEN;
437 
438 	spin_lock_irqsave(&ltq_asc_lock, flags);
439 
440 	/* set up CON */
441 	ltq_w32_mask(0, con, port->membase + LTQ_ASC_CON);
442 
443 	/* Set baud rate - take a divider of 2 into account */
444 	baud = uart_get_baud_rate(port, new, old, 0, port->uartclk / 16);
445 	divisor = uart_get_divisor(port, baud);
446 	divisor = divisor / 2 - 1;
447 
448 	/* disable the baudrate generator */
449 	ltq_w32_mask(ASCCON_R, 0, port->membase + LTQ_ASC_CON);
450 
451 	/* make sure the fractional divider is off */
452 	ltq_w32_mask(ASCCON_FDE, 0, port->membase + LTQ_ASC_CON);
453 
454 	/* set up to use divisor of 2 */
455 	ltq_w32_mask(ASCCON_BRS, 0, port->membase + LTQ_ASC_CON);
456 
457 	/* now we can write the new baudrate into the register */
458 	ltq_w32(divisor, port->membase + LTQ_ASC_BG);
459 
460 	/* turn the baudrate generator back on */
461 	ltq_w32_mask(0, ASCCON_R, port->membase + LTQ_ASC_CON);
462 
463 	/* enable rx */
464 	ltq_w32(ASCWHBSTATE_SETREN, port->membase + LTQ_ASC_WHBSTATE);
465 
466 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
467 
468 	/* Don't rewrite B0 */
469 	if (tty_termios_baud_rate(new))
470 		tty_termios_encode_baud_rate(new, baud, baud);
471 
472 	uart_update_timeout(port, cflag, baud);
473 }
474 
475 static const char*
476 lqasc_type(struct uart_port *port)
477 {
478 	if (port->type == PORT_LTQ_ASC)
479 		return DRVNAME;
480 	else
481 		return NULL;
482 }
483 
484 static void
485 lqasc_release_port(struct uart_port *port)
486 {
487 	struct platform_device *pdev = to_platform_device(port->dev);
488 
489 	if (port->flags & UPF_IOREMAP) {
490 		devm_iounmap(&pdev->dev, port->membase);
491 		port->membase = NULL;
492 	}
493 }
494 
495 static int
496 lqasc_request_port(struct uart_port *port)
497 {
498 	struct platform_device *pdev = to_platform_device(port->dev);
499 	struct resource *res;
500 	int size;
501 
502 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
503 	if (!res) {
504 		dev_err(&pdev->dev, "cannot obtain I/O memory region");
505 		return -ENODEV;
506 	}
507 	size = resource_size(res);
508 
509 	res = devm_request_mem_region(&pdev->dev, res->start,
510 		size, dev_name(&pdev->dev));
511 	if (!res) {
512 		dev_err(&pdev->dev, "cannot request I/O memory region");
513 		return -EBUSY;
514 	}
515 
516 	if (port->flags & UPF_IOREMAP) {
517 		port->membase = devm_ioremap_nocache(&pdev->dev,
518 			port->mapbase, size);
519 		if (port->membase == NULL)
520 			return -ENOMEM;
521 	}
522 	return 0;
523 }
524 
525 static void
526 lqasc_config_port(struct uart_port *port, int flags)
527 {
528 	if (flags & UART_CONFIG_TYPE) {
529 		port->type = PORT_LTQ_ASC;
530 		lqasc_request_port(port);
531 	}
532 }
533 
534 static int
535 lqasc_verify_port(struct uart_port *port,
536 	struct serial_struct *ser)
537 {
538 	int ret = 0;
539 	if (ser->type != PORT_UNKNOWN && ser->type != PORT_LTQ_ASC)
540 		ret = -EINVAL;
541 	if (ser->irq < 0 || ser->irq >= NR_IRQS)
542 		ret = -EINVAL;
543 	if (ser->baud_base < 9600)
544 		ret = -EINVAL;
545 	return ret;
546 }
547 
548 static const struct uart_ops lqasc_pops = {
549 	.tx_empty =	lqasc_tx_empty,
550 	.set_mctrl =	lqasc_set_mctrl,
551 	.get_mctrl =	lqasc_get_mctrl,
552 	.stop_tx =	lqasc_stop_tx,
553 	.start_tx =	lqasc_start_tx,
554 	.stop_rx =	lqasc_stop_rx,
555 	.break_ctl =	lqasc_break_ctl,
556 	.startup =	lqasc_startup,
557 	.shutdown =	lqasc_shutdown,
558 	.set_termios =	lqasc_set_termios,
559 	.type =		lqasc_type,
560 	.release_port =	lqasc_release_port,
561 	.request_port =	lqasc_request_port,
562 	.config_port =	lqasc_config_port,
563 	.verify_port =	lqasc_verify_port,
564 };
565 
566 static void
567 lqasc_console_putchar(struct uart_port *port, int ch)
568 {
569 	int fifofree;
570 
571 	if (!port->membase)
572 		return;
573 
574 	do {
575 		fifofree = (ltq_r32(port->membase + LTQ_ASC_FSTAT)
576 			& ASCFSTAT_TXFREEMASK) >> ASCFSTAT_TXFREEOFF;
577 	} while (fifofree == 0);
578 	ltq_w8(ch, port->membase + LTQ_ASC_TBUF);
579 }
580 
581 static void lqasc_serial_port_write(struct uart_port *port, const char *s,
582 				    u_int count)
583 {
584 	unsigned long flags;
585 
586 	spin_lock_irqsave(&ltq_asc_lock, flags);
587 	uart_console_write(port, s, count, lqasc_console_putchar);
588 	spin_unlock_irqrestore(&ltq_asc_lock, flags);
589 }
590 
591 static void
592 lqasc_console_write(struct console *co, const char *s, u_int count)
593 {
594 	struct ltq_uart_port *ltq_port;
595 
596 	if (co->index >= MAXPORTS)
597 		return;
598 
599 	ltq_port = lqasc_port[co->index];
600 	if (!ltq_port)
601 		return;
602 
603 	lqasc_serial_port_write(&ltq_port->port, s, count);
604 }
605 
606 static int __init
607 lqasc_console_setup(struct console *co, char *options)
608 {
609 	struct ltq_uart_port *ltq_port;
610 	struct uart_port *port;
611 	int baud = 115200;
612 	int bits = 8;
613 	int parity = 'n';
614 	int flow = 'n';
615 
616 	if (co->index >= MAXPORTS)
617 		return -ENODEV;
618 
619 	ltq_port = lqasc_port[co->index];
620 	if (!ltq_port)
621 		return -ENODEV;
622 
623 	port = &ltq_port->port;
624 
625 	if (!IS_ERR(ltq_port->clk))
626 		clk_enable(ltq_port->clk);
627 
628 	port->uartclk = clk_get_rate(ltq_port->fpiclk);
629 
630 	if (options)
631 		uart_parse_options(options, &baud, &parity, &bits, &flow);
632 	return uart_set_options(port, co, baud, parity, bits, flow);
633 }
634 
635 static struct console lqasc_console = {
636 	.name =		"ttyLTQ",
637 	.write =	lqasc_console_write,
638 	.device =	uart_console_device,
639 	.setup =	lqasc_console_setup,
640 	.flags =	CON_PRINTBUFFER,
641 	.index =	-1,
642 	.data =		&lqasc_reg,
643 };
644 
645 static int __init
646 lqasc_console_init(void)
647 {
648 	register_console(&lqasc_console);
649 	return 0;
650 }
651 console_initcall(lqasc_console_init);
652 
653 static void lqasc_serial_early_console_write(struct console *co,
654 					     const char *s,
655 					     u_int count)
656 {
657 	struct earlycon_device *dev = co->data;
658 
659 	lqasc_serial_port_write(&dev->port, s, count);
660 }
661 
662 static int __init
663 lqasc_serial_early_console_setup(struct earlycon_device *device,
664 				 const char *opt)
665 {
666 	if (!device->port.membase)
667 		return -ENODEV;
668 
669 	device->con->write = lqasc_serial_early_console_write;
670 	return 0;
671 }
672 OF_EARLYCON_DECLARE(lantiq, DRVNAME, lqasc_serial_early_console_setup);
673 
674 static struct uart_driver lqasc_reg = {
675 	.owner =	THIS_MODULE,
676 	.driver_name =	DRVNAME,
677 	.dev_name =	"ttyLTQ",
678 	.major =	0,
679 	.minor =	0,
680 	.nr =		MAXPORTS,
681 	.cons =		&lqasc_console,
682 };
683 
684 static int __init
685 lqasc_probe(struct platform_device *pdev)
686 {
687 	struct device_node *node = pdev->dev.of_node;
688 	struct ltq_uart_port *ltq_port;
689 	struct uart_port *port;
690 	struct resource *mmres, irqres[3];
691 	int line = 0;
692 	int ret;
693 
694 	mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
695 	ret = of_irq_to_resource_table(node, irqres, 3);
696 	if (!mmres || (ret != 3)) {
697 		dev_err(&pdev->dev,
698 			"failed to get memory/irq for serial port\n");
699 		return -ENODEV;
700 	}
701 
702 	/* check if this is the console port */
703 	if (mmres->start != CPHYSADDR(LTQ_EARLY_ASC))
704 		line = 1;
705 
706 	if (lqasc_port[line]) {
707 		dev_err(&pdev->dev, "port %d already allocated\n", line);
708 		return -EBUSY;
709 	}
710 
711 	ltq_port = devm_kzalloc(&pdev->dev, sizeof(struct ltq_uart_port),
712 			GFP_KERNEL);
713 	if (!ltq_port)
714 		return -ENOMEM;
715 
716 	port = &ltq_port->port;
717 
718 	port->iotype	= SERIAL_IO_MEM;
719 	port->flags	= UPF_BOOT_AUTOCONF | UPF_IOREMAP;
720 	port->ops	= &lqasc_pops;
721 	port->fifosize	= 16;
722 	port->type	= PORT_LTQ_ASC,
723 	port->line	= line;
724 	port->dev	= &pdev->dev;
725 	/* unused, just to be backward-compatible */
726 	port->irq	= irqres[0].start;
727 	port->mapbase	= mmres->start;
728 
729 	ltq_port->fpiclk = clk_get_fpi();
730 	if (IS_ERR(ltq_port->fpiclk)) {
731 		pr_err("failed to get fpi clk\n");
732 		return -ENOENT;
733 	}
734 
735 	/* not all asc ports have clock gates, lets ignore the return code */
736 	ltq_port->clk = clk_get(&pdev->dev, NULL);
737 
738 	ltq_port->tx_irq = irqres[0].start;
739 	ltq_port->rx_irq = irqres[1].start;
740 	ltq_port->err_irq = irqres[2].start;
741 
742 	lqasc_port[line] = ltq_port;
743 	platform_set_drvdata(pdev, ltq_port);
744 
745 	ret = uart_add_one_port(&lqasc_reg, port);
746 
747 	return ret;
748 }
749 
750 static const struct of_device_id ltq_asc_match[] = {
751 	{ .compatible = DRVNAME },
752 	{},
753 };
754 
755 static struct platform_driver lqasc_driver = {
756 	.driver		= {
757 		.name	= DRVNAME,
758 		.of_match_table = ltq_asc_match,
759 	},
760 };
761 
762 int __init
763 init_lqasc(void)
764 {
765 	int ret;
766 
767 	ret = uart_register_driver(&lqasc_reg);
768 	if (ret != 0)
769 		return ret;
770 
771 	ret = platform_driver_probe(&lqasc_driver, lqasc_probe);
772 	if (ret != 0)
773 		uart_unregister_driver(&lqasc_reg);
774 
775 	return ret;
776 }
777 device_initcall(init_lqasc);
778