xref: /linux/drivers/tty/serial/amba-pl010.c (revision e58e871becec2d3b04ed91c0c16fe8deac9c9dfa)
1 /*
2  *  Driver for AMBA serial ports
3  *
4  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
5  *
6  *  Copyright 1999 ARM Limited
7  *  Copyright (C) 2000 Deep Blue Solutions Ltd.
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, write to the Free Software
21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
22  *
23  * This is a generic driver for ARM AMBA-type serial ports.  They
24  * have a lot of 16550-like features, but are not register compatible.
25  * Note that although they do have CTS, DCD and DSR inputs, they do
26  * not have an RI input, nor do they have DTR or RTS outputs.  If
27  * required, these have to be supplied via some other means (eg, GPIO)
28  * and hooked into this driver.
29  */
30 
31 #if defined(CONFIG_SERIAL_AMBA_PL010_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
32 #define SUPPORT_SYSRQ
33 #endif
34 
35 #include <linux/module.h>
36 #include <linux/ioport.h>
37 #include <linux/init.h>
38 #include <linux/console.h>
39 #include <linux/sysrq.h>
40 #include <linux/device.h>
41 #include <linux/tty.h>
42 #include <linux/tty_flip.h>
43 #include <linux/serial_core.h>
44 #include <linux/serial.h>
45 #include <linux/amba/bus.h>
46 #include <linux/amba/serial.h>
47 #include <linux/clk.h>
48 #include <linux/slab.h>
49 #include <linux/io.h>
50 
51 #define UART_NR		8
52 
53 #define SERIAL_AMBA_MAJOR	204
54 #define SERIAL_AMBA_MINOR	16
55 #define SERIAL_AMBA_NR		UART_NR
56 
57 #define AMBA_ISR_PASS_LIMIT	256
58 
59 #define UART_RX_DATA(s)		(((s) & UART01x_FR_RXFE) == 0)
60 #define UART_TX_READY(s)	(((s) & UART01x_FR_TXFF) == 0)
61 
62 #define UART_DUMMY_RSR_RX	256
63 #define UART_PORT_SIZE		64
64 
65 /*
66  * We wrap our port structure around the generic uart_port.
67  */
68 struct uart_amba_port {
69 	struct uart_port	port;
70 	struct clk		*clk;
71 	struct amba_device	*dev;
72 	struct amba_pl010_data	*data;
73 	unsigned int		old_status;
74 };
75 
76 static void pl010_stop_tx(struct uart_port *port)
77 {
78 	struct uart_amba_port *uap =
79 		container_of(port, struct uart_amba_port, port);
80 	unsigned int cr;
81 
82 	cr = readb(uap->port.membase + UART010_CR);
83 	cr &= ~UART010_CR_TIE;
84 	writel(cr, uap->port.membase + UART010_CR);
85 }
86 
87 static void pl010_start_tx(struct uart_port *port)
88 {
89 	struct uart_amba_port *uap =
90 		container_of(port, struct uart_amba_port, port);
91 	unsigned int cr;
92 
93 	cr = readb(uap->port.membase + UART010_CR);
94 	cr |= UART010_CR_TIE;
95 	writel(cr, uap->port.membase + UART010_CR);
96 }
97 
98 static void pl010_stop_rx(struct uart_port *port)
99 {
100 	struct uart_amba_port *uap =
101 		container_of(port, struct uart_amba_port, port);
102 	unsigned int cr;
103 
104 	cr = readb(uap->port.membase + UART010_CR);
105 	cr &= ~(UART010_CR_RIE | UART010_CR_RTIE);
106 	writel(cr, uap->port.membase + UART010_CR);
107 }
108 
109 static void pl010_disable_ms(struct uart_port *port)
110 {
111 	struct uart_amba_port *uap = (struct uart_amba_port *)port;
112 	unsigned int cr;
113 
114 	cr = readb(uap->port.membase + UART010_CR);
115 	cr &= ~UART010_CR_MSIE;
116 	writel(cr, uap->port.membase + UART010_CR);
117 }
118 
119 static void pl010_enable_ms(struct uart_port *port)
120 {
121 	struct uart_amba_port *uap =
122 		container_of(port, struct uart_amba_port, port);
123 	unsigned int cr;
124 
125 	cr = readb(uap->port.membase + UART010_CR);
126 	cr |= UART010_CR_MSIE;
127 	writel(cr, uap->port.membase + UART010_CR);
128 }
129 
130 static void pl010_rx_chars(struct uart_amba_port *uap)
131 {
132 	unsigned int status, ch, flag, rsr, max_count = 256;
133 
134 	status = readb(uap->port.membase + UART01x_FR);
135 	while (UART_RX_DATA(status) && max_count--) {
136 		ch = readb(uap->port.membase + UART01x_DR);
137 		flag = TTY_NORMAL;
138 
139 		uap->port.icount.rx++;
140 
141 		/*
142 		 * Note that the error handling code is
143 		 * out of the main execution path
144 		 */
145 		rsr = readb(uap->port.membase + UART01x_RSR) | UART_DUMMY_RSR_RX;
146 		if (unlikely(rsr & UART01x_RSR_ANY)) {
147 			writel(0, uap->port.membase + UART01x_ECR);
148 
149 			if (rsr & UART01x_RSR_BE) {
150 				rsr &= ~(UART01x_RSR_FE | UART01x_RSR_PE);
151 				uap->port.icount.brk++;
152 				if (uart_handle_break(&uap->port))
153 					goto ignore_char;
154 			} else if (rsr & UART01x_RSR_PE)
155 				uap->port.icount.parity++;
156 			else if (rsr & UART01x_RSR_FE)
157 				uap->port.icount.frame++;
158 			if (rsr & UART01x_RSR_OE)
159 				uap->port.icount.overrun++;
160 
161 			rsr &= uap->port.read_status_mask;
162 
163 			if (rsr & UART01x_RSR_BE)
164 				flag = TTY_BREAK;
165 			else if (rsr & UART01x_RSR_PE)
166 				flag = TTY_PARITY;
167 			else if (rsr & UART01x_RSR_FE)
168 				flag = TTY_FRAME;
169 		}
170 
171 		if (uart_handle_sysrq_char(&uap->port, ch))
172 			goto ignore_char;
173 
174 		uart_insert_char(&uap->port, rsr, UART01x_RSR_OE, ch, flag);
175 
176 	ignore_char:
177 		status = readb(uap->port.membase + UART01x_FR);
178 	}
179 	spin_unlock(&uap->port.lock);
180 	tty_flip_buffer_push(&uap->port.state->port);
181 	spin_lock(&uap->port.lock);
182 }
183 
184 static void pl010_tx_chars(struct uart_amba_port *uap)
185 {
186 	struct circ_buf *xmit = &uap->port.state->xmit;
187 	int count;
188 
189 	if (uap->port.x_char) {
190 		writel(uap->port.x_char, uap->port.membase + UART01x_DR);
191 		uap->port.icount.tx++;
192 		uap->port.x_char = 0;
193 		return;
194 	}
195 	if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) {
196 		pl010_stop_tx(&uap->port);
197 		return;
198 	}
199 
200 	count = uap->port.fifosize >> 1;
201 	do {
202 		writel(xmit->buf[xmit->tail], uap->port.membase + UART01x_DR);
203 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
204 		uap->port.icount.tx++;
205 		if (uart_circ_empty(xmit))
206 			break;
207 	} while (--count > 0);
208 
209 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
210 		uart_write_wakeup(&uap->port);
211 
212 	if (uart_circ_empty(xmit))
213 		pl010_stop_tx(&uap->port);
214 }
215 
216 static void pl010_modem_status(struct uart_amba_port *uap)
217 {
218 	unsigned int status, delta;
219 
220 	writel(0, uap->port.membase + UART010_ICR);
221 
222 	status = readb(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
223 
224 	delta = status ^ uap->old_status;
225 	uap->old_status = status;
226 
227 	if (!delta)
228 		return;
229 
230 	if (delta & UART01x_FR_DCD)
231 		uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD);
232 
233 	if (delta & UART01x_FR_DSR)
234 		uap->port.icount.dsr++;
235 
236 	if (delta & UART01x_FR_CTS)
237 		uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS);
238 
239 	wake_up_interruptible(&uap->port.state->port.delta_msr_wait);
240 }
241 
242 static irqreturn_t pl010_int(int irq, void *dev_id)
243 {
244 	struct uart_amba_port *uap = dev_id;
245 	unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
246 	int handled = 0;
247 
248 	spin_lock(&uap->port.lock);
249 
250 	status = readb(uap->port.membase + UART010_IIR);
251 	if (status) {
252 		do {
253 			if (status & (UART010_IIR_RTIS | UART010_IIR_RIS))
254 				pl010_rx_chars(uap);
255 			if (status & UART010_IIR_MIS)
256 				pl010_modem_status(uap);
257 			if (status & UART010_IIR_TIS)
258 				pl010_tx_chars(uap);
259 
260 			if (pass_counter-- == 0)
261 				break;
262 
263 			status = readb(uap->port.membase + UART010_IIR);
264 		} while (status & (UART010_IIR_RTIS | UART010_IIR_RIS |
265 				   UART010_IIR_TIS));
266 		handled = 1;
267 	}
268 
269 	spin_unlock(&uap->port.lock);
270 
271 	return IRQ_RETVAL(handled);
272 }
273 
274 static unsigned int pl010_tx_empty(struct uart_port *port)
275 {
276 	struct uart_amba_port *uap =
277 		container_of(port, struct uart_amba_port, port);
278 	unsigned int status = readb(uap->port.membase + UART01x_FR);
279 	return status & UART01x_FR_BUSY ? 0 : TIOCSER_TEMT;
280 }
281 
282 static unsigned int pl010_get_mctrl(struct uart_port *port)
283 {
284 	struct uart_amba_port *uap =
285 		container_of(port, struct uart_amba_port, port);
286 	unsigned int result = 0;
287 	unsigned int status;
288 
289 	status = readb(uap->port.membase + UART01x_FR);
290 	if (status & UART01x_FR_DCD)
291 		result |= TIOCM_CAR;
292 	if (status & UART01x_FR_DSR)
293 		result |= TIOCM_DSR;
294 	if (status & UART01x_FR_CTS)
295 		result |= TIOCM_CTS;
296 
297 	return result;
298 }
299 
300 static void pl010_set_mctrl(struct uart_port *port, unsigned int mctrl)
301 {
302 	struct uart_amba_port *uap =
303 		container_of(port, struct uart_amba_port, port);
304 
305 	if (uap->data)
306 		uap->data->set_mctrl(uap->dev, uap->port.membase, mctrl);
307 }
308 
309 static void pl010_break_ctl(struct uart_port *port, int break_state)
310 {
311 	struct uart_amba_port *uap =
312 		container_of(port, struct uart_amba_port, port);
313 	unsigned long flags;
314 	unsigned int lcr_h;
315 
316 	spin_lock_irqsave(&uap->port.lock, flags);
317 	lcr_h = readb(uap->port.membase + UART010_LCRH);
318 	if (break_state == -1)
319 		lcr_h |= UART01x_LCRH_BRK;
320 	else
321 		lcr_h &= ~UART01x_LCRH_BRK;
322 	writel(lcr_h, uap->port.membase + UART010_LCRH);
323 	spin_unlock_irqrestore(&uap->port.lock, flags);
324 }
325 
326 static int pl010_startup(struct uart_port *port)
327 {
328 	struct uart_amba_port *uap =
329 		container_of(port, struct uart_amba_port, port);
330 	int retval;
331 
332 	/*
333 	 * Try to enable the clock producer.
334 	 */
335 	retval = clk_prepare_enable(uap->clk);
336 	if (retval)
337 		goto out;
338 
339 	uap->port.uartclk = clk_get_rate(uap->clk);
340 
341 	/*
342 	 * Allocate the IRQ
343 	 */
344 	retval = request_irq(uap->port.irq, pl010_int, 0, "uart-pl010", uap);
345 	if (retval)
346 		goto clk_dis;
347 
348 	/*
349 	 * initialise the old status of the modem signals
350 	 */
351 	uap->old_status = readb(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
352 
353 	/*
354 	 * Finally, enable interrupts
355 	 */
356 	writel(UART01x_CR_UARTEN | UART010_CR_RIE | UART010_CR_RTIE,
357 	       uap->port.membase + UART010_CR);
358 
359 	return 0;
360 
361  clk_dis:
362 	clk_disable_unprepare(uap->clk);
363  out:
364 	return retval;
365 }
366 
367 static void pl010_shutdown(struct uart_port *port)
368 {
369 	struct uart_amba_port *uap =
370 		container_of(port, struct uart_amba_port, port);
371 
372 	/*
373 	 * Free the interrupt
374 	 */
375 	free_irq(uap->port.irq, uap);
376 
377 	/*
378 	 * disable all interrupts, disable the port
379 	 */
380 	writel(0, uap->port.membase + UART010_CR);
381 
382 	/* disable break condition and fifos */
383 	writel(readb(uap->port.membase + UART010_LCRH) &
384 		~(UART01x_LCRH_BRK | UART01x_LCRH_FEN),
385 	       uap->port.membase + UART010_LCRH);
386 
387 	/*
388 	 * Shut down the clock producer
389 	 */
390 	clk_disable_unprepare(uap->clk);
391 }
392 
393 static void
394 pl010_set_termios(struct uart_port *port, struct ktermios *termios,
395 		     struct ktermios *old)
396 {
397 	struct uart_amba_port *uap =
398 		container_of(port, struct uart_amba_port, port);
399 	unsigned int lcr_h, old_cr;
400 	unsigned long flags;
401 	unsigned int baud, quot;
402 
403 	/*
404 	 * Ask the core to calculate the divisor for us.
405 	 */
406 	baud = uart_get_baud_rate(port, termios, old, 0, uap->port.uartclk/16);
407 	quot = uart_get_divisor(port, baud);
408 
409 	switch (termios->c_cflag & CSIZE) {
410 	case CS5:
411 		lcr_h = UART01x_LCRH_WLEN_5;
412 		break;
413 	case CS6:
414 		lcr_h = UART01x_LCRH_WLEN_6;
415 		break;
416 	case CS7:
417 		lcr_h = UART01x_LCRH_WLEN_7;
418 		break;
419 	default: // CS8
420 		lcr_h = UART01x_LCRH_WLEN_8;
421 		break;
422 	}
423 	if (termios->c_cflag & CSTOPB)
424 		lcr_h |= UART01x_LCRH_STP2;
425 	if (termios->c_cflag & PARENB) {
426 		lcr_h |= UART01x_LCRH_PEN;
427 		if (!(termios->c_cflag & PARODD))
428 			lcr_h |= UART01x_LCRH_EPS;
429 	}
430 	if (uap->port.fifosize > 1)
431 		lcr_h |= UART01x_LCRH_FEN;
432 
433 	spin_lock_irqsave(&uap->port.lock, flags);
434 
435 	/*
436 	 * Update the per-port timeout.
437 	 */
438 	uart_update_timeout(port, termios->c_cflag, baud);
439 
440 	uap->port.read_status_mask = UART01x_RSR_OE;
441 	if (termios->c_iflag & INPCK)
442 		uap->port.read_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
443 	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
444 		uap->port.read_status_mask |= UART01x_RSR_BE;
445 
446 	/*
447 	 * Characters to ignore
448 	 */
449 	uap->port.ignore_status_mask = 0;
450 	if (termios->c_iflag & IGNPAR)
451 		uap->port.ignore_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
452 	if (termios->c_iflag & IGNBRK) {
453 		uap->port.ignore_status_mask |= UART01x_RSR_BE;
454 		/*
455 		 * If we're ignoring parity and break indicators,
456 		 * ignore overruns too (for real raw support).
457 		 */
458 		if (termios->c_iflag & IGNPAR)
459 			uap->port.ignore_status_mask |= UART01x_RSR_OE;
460 	}
461 
462 	/*
463 	 * Ignore all characters if CREAD is not set.
464 	 */
465 	if ((termios->c_cflag & CREAD) == 0)
466 		uap->port.ignore_status_mask |= UART_DUMMY_RSR_RX;
467 
468 	/* first, disable everything */
469 	old_cr = readb(uap->port.membase + UART010_CR) & ~UART010_CR_MSIE;
470 
471 	if (UART_ENABLE_MS(port, termios->c_cflag))
472 		old_cr |= UART010_CR_MSIE;
473 
474 	writel(0, uap->port.membase + UART010_CR);
475 
476 	/* Set baud rate */
477 	quot -= 1;
478 	writel((quot & 0xf00) >> 8, uap->port.membase + UART010_LCRM);
479 	writel(quot & 0xff, uap->port.membase + UART010_LCRL);
480 
481 	/*
482 	 * ----------v----------v----------v----------v-----
483 	 * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
484 	 * ----------^----------^----------^----------^-----
485 	 */
486 	writel(lcr_h, uap->port.membase + UART010_LCRH);
487 	writel(old_cr, uap->port.membase + UART010_CR);
488 
489 	spin_unlock_irqrestore(&uap->port.lock, flags);
490 }
491 
492 static void pl010_set_ldisc(struct uart_port *port, struct ktermios *termios)
493 {
494 	if (termios->c_line == N_PPS) {
495 		port->flags |= UPF_HARDPPS_CD;
496 		spin_lock_irq(&port->lock);
497 		pl010_enable_ms(port);
498 		spin_unlock_irq(&port->lock);
499 	} else {
500 		port->flags &= ~UPF_HARDPPS_CD;
501 		if (!UART_ENABLE_MS(port, termios->c_cflag)) {
502 			spin_lock_irq(&port->lock);
503 			pl010_disable_ms(port);
504 			spin_unlock_irq(&port->lock);
505 		}
506 	}
507 }
508 
509 static const char *pl010_type(struct uart_port *port)
510 {
511 	return port->type == PORT_AMBA ? "AMBA" : NULL;
512 }
513 
514 /*
515  * Release the memory region(s) being used by 'port'
516  */
517 static void pl010_release_port(struct uart_port *port)
518 {
519 	release_mem_region(port->mapbase, UART_PORT_SIZE);
520 }
521 
522 /*
523  * Request the memory region(s) being used by 'port'
524  */
525 static int pl010_request_port(struct uart_port *port)
526 {
527 	return request_mem_region(port->mapbase, UART_PORT_SIZE, "uart-pl010")
528 			!= NULL ? 0 : -EBUSY;
529 }
530 
531 /*
532  * Configure/autoconfigure the port.
533  */
534 static void pl010_config_port(struct uart_port *port, int flags)
535 {
536 	if (flags & UART_CONFIG_TYPE) {
537 		port->type = PORT_AMBA;
538 		pl010_request_port(port);
539 	}
540 }
541 
542 /*
543  * verify the new serial_struct (for TIOCSSERIAL).
544  */
545 static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser)
546 {
547 	int ret = 0;
548 	if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
549 		ret = -EINVAL;
550 	if (ser->irq < 0 || ser->irq >= nr_irqs)
551 		ret = -EINVAL;
552 	if (ser->baud_base < 9600)
553 		ret = -EINVAL;
554 	return ret;
555 }
556 
557 static const struct uart_ops amba_pl010_pops = {
558 	.tx_empty	= pl010_tx_empty,
559 	.set_mctrl	= pl010_set_mctrl,
560 	.get_mctrl	= pl010_get_mctrl,
561 	.stop_tx	= pl010_stop_tx,
562 	.start_tx	= pl010_start_tx,
563 	.stop_rx	= pl010_stop_rx,
564 	.enable_ms	= pl010_enable_ms,
565 	.break_ctl	= pl010_break_ctl,
566 	.startup	= pl010_startup,
567 	.shutdown	= pl010_shutdown,
568 	.set_termios	= pl010_set_termios,
569 	.set_ldisc	= pl010_set_ldisc,
570 	.type		= pl010_type,
571 	.release_port	= pl010_release_port,
572 	.request_port	= pl010_request_port,
573 	.config_port	= pl010_config_port,
574 	.verify_port	= pl010_verify_port,
575 };
576 
577 static struct uart_amba_port *amba_ports[UART_NR];
578 
579 #ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE
580 
581 static void pl010_console_putchar(struct uart_port *port, int ch)
582 {
583 	struct uart_amba_port *uap =
584 		container_of(port, struct uart_amba_port, port);
585 	unsigned int status;
586 
587 	do {
588 		status = readb(uap->port.membase + UART01x_FR);
589 		barrier();
590 	} while (!UART_TX_READY(status));
591 	writel(ch, uap->port.membase + UART01x_DR);
592 }
593 
594 static void
595 pl010_console_write(struct console *co, const char *s, unsigned int count)
596 {
597 	struct uart_amba_port *uap = amba_ports[co->index];
598 	unsigned int status, old_cr;
599 
600 	clk_enable(uap->clk);
601 
602 	/*
603 	 *	First save the CR then disable the interrupts
604 	 */
605 	old_cr = readb(uap->port.membase + UART010_CR);
606 	writel(UART01x_CR_UARTEN, uap->port.membase + UART010_CR);
607 
608 	uart_console_write(&uap->port, s, count, pl010_console_putchar);
609 
610 	/*
611 	 *	Finally, wait for transmitter to become empty
612 	 *	and restore the TCR
613 	 */
614 	do {
615 		status = readb(uap->port.membase + UART01x_FR);
616 		barrier();
617 	} while (status & UART01x_FR_BUSY);
618 	writel(old_cr, uap->port.membase + UART010_CR);
619 
620 	clk_disable(uap->clk);
621 }
622 
623 static void __init
624 pl010_console_get_options(struct uart_amba_port *uap, int *baud,
625 			     int *parity, int *bits)
626 {
627 	if (readb(uap->port.membase + UART010_CR) & UART01x_CR_UARTEN) {
628 		unsigned int lcr_h, quot;
629 		lcr_h = readb(uap->port.membase + UART010_LCRH);
630 
631 		*parity = 'n';
632 		if (lcr_h & UART01x_LCRH_PEN) {
633 			if (lcr_h & UART01x_LCRH_EPS)
634 				*parity = 'e';
635 			else
636 				*parity = 'o';
637 		}
638 
639 		if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
640 			*bits = 7;
641 		else
642 			*bits = 8;
643 
644 		quot = readb(uap->port.membase + UART010_LCRL) |
645 		       readb(uap->port.membase + UART010_LCRM) << 8;
646 		*baud = uap->port.uartclk / (16 * (quot + 1));
647 	}
648 }
649 
650 static int __init pl010_console_setup(struct console *co, char *options)
651 {
652 	struct uart_amba_port *uap;
653 	int baud = 38400;
654 	int bits = 8;
655 	int parity = 'n';
656 	int flow = 'n';
657 	int ret;
658 
659 	/*
660 	 * Check whether an invalid uart number has been specified, and
661 	 * if so, search for the first available port that does have
662 	 * console support.
663 	 */
664 	if (co->index >= UART_NR)
665 		co->index = 0;
666 	uap = amba_ports[co->index];
667 	if (!uap)
668 		return -ENODEV;
669 
670 	ret = clk_prepare(uap->clk);
671 	if (ret)
672 		return ret;
673 
674 	uap->port.uartclk = clk_get_rate(uap->clk);
675 
676 	if (options)
677 		uart_parse_options(options, &baud, &parity, &bits, &flow);
678 	else
679 		pl010_console_get_options(uap, &baud, &parity, &bits);
680 
681 	return uart_set_options(&uap->port, co, baud, parity, bits, flow);
682 }
683 
684 static struct uart_driver amba_reg;
685 static struct console amba_console = {
686 	.name		= "ttyAM",
687 	.write		= pl010_console_write,
688 	.device		= uart_console_device,
689 	.setup		= pl010_console_setup,
690 	.flags		= CON_PRINTBUFFER,
691 	.index		= -1,
692 	.data		= &amba_reg,
693 };
694 
695 #define AMBA_CONSOLE	&amba_console
696 #else
697 #define AMBA_CONSOLE	NULL
698 #endif
699 
700 static struct uart_driver amba_reg = {
701 	.owner			= THIS_MODULE,
702 	.driver_name		= "ttyAM",
703 	.dev_name		= "ttyAM",
704 	.major			= SERIAL_AMBA_MAJOR,
705 	.minor			= SERIAL_AMBA_MINOR,
706 	.nr			= UART_NR,
707 	.cons			= AMBA_CONSOLE,
708 };
709 
710 static int pl010_probe(struct amba_device *dev, const struct amba_id *id)
711 {
712 	struct uart_amba_port *uap;
713 	void __iomem *base;
714 	int i, ret;
715 
716 	for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
717 		if (amba_ports[i] == NULL)
718 			break;
719 
720 	if (i == ARRAY_SIZE(amba_ports))
721 		return -EBUSY;
722 
723 	uap = devm_kzalloc(&dev->dev, sizeof(struct uart_amba_port),
724 			   GFP_KERNEL);
725 	if (!uap)
726 		return -ENOMEM;
727 
728 	base = devm_ioremap(&dev->dev, dev->res.start,
729 			    resource_size(&dev->res));
730 	if (!base)
731 		return -ENOMEM;
732 
733 	uap->clk = devm_clk_get(&dev->dev, NULL);
734 	if (IS_ERR(uap->clk))
735 		return PTR_ERR(uap->clk);
736 
737 	uap->port.dev = &dev->dev;
738 	uap->port.mapbase = dev->res.start;
739 	uap->port.membase = base;
740 	uap->port.iotype = UPIO_MEM;
741 	uap->port.irq = dev->irq[0];
742 	uap->port.fifosize = 16;
743 	uap->port.ops = &amba_pl010_pops;
744 	uap->port.flags = UPF_BOOT_AUTOCONF;
745 	uap->port.line = i;
746 	uap->dev = dev;
747 	uap->data = dev_get_platdata(&dev->dev);
748 
749 	amba_ports[i] = uap;
750 
751 	amba_set_drvdata(dev, uap);
752 	ret = uart_add_one_port(&amba_reg, &uap->port);
753 	if (ret)
754 		amba_ports[i] = NULL;
755 
756 	return ret;
757 }
758 
759 static int pl010_remove(struct amba_device *dev)
760 {
761 	struct uart_amba_port *uap = amba_get_drvdata(dev);
762 	int i;
763 
764 	uart_remove_one_port(&amba_reg, &uap->port);
765 
766 	for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
767 		if (amba_ports[i] == uap)
768 			amba_ports[i] = NULL;
769 
770 	return 0;
771 }
772 
773 #ifdef CONFIG_PM_SLEEP
774 static int pl010_suspend(struct device *dev)
775 {
776 	struct uart_amba_port *uap = dev_get_drvdata(dev);
777 
778 	if (uap)
779 		uart_suspend_port(&amba_reg, &uap->port);
780 
781 	return 0;
782 }
783 
784 static int pl010_resume(struct device *dev)
785 {
786 	struct uart_amba_port *uap = dev_get_drvdata(dev);
787 
788 	if (uap)
789 		uart_resume_port(&amba_reg, &uap->port);
790 
791 	return 0;
792 }
793 #endif
794 
795 static SIMPLE_DEV_PM_OPS(pl010_dev_pm_ops, pl010_suspend, pl010_resume);
796 
797 static struct amba_id pl010_ids[] = {
798 	{
799 		.id	= 0x00041010,
800 		.mask	= 0x000fffff,
801 	},
802 	{ 0, 0 },
803 };
804 
805 MODULE_DEVICE_TABLE(amba, pl010_ids);
806 
807 static struct amba_driver pl010_driver = {
808 	.drv = {
809 		.name	= "uart-pl010",
810 		.pm	= &pl010_dev_pm_ops,
811 	},
812 	.id_table	= pl010_ids,
813 	.probe		= pl010_probe,
814 	.remove		= pl010_remove,
815 };
816 
817 static int __init pl010_init(void)
818 {
819 	int ret;
820 
821 	printk(KERN_INFO "Serial: AMBA driver\n");
822 
823 	ret = uart_register_driver(&amba_reg);
824 	if (ret == 0) {
825 		ret = amba_driver_register(&pl010_driver);
826 		if (ret)
827 			uart_unregister_driver(&amba_reg);
828 	}
829 	return ret;
830 }
831 
832 static void __exit pl010_exit(void)
833 {
834 	amba_driver_unregister(&pl010_driver);
835 	uart_unregister_driver(&amba_reg);
836 }
837 
838 module_init(pl010_init);
839 module_exit(pl010_exit);
840 
841 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
842 MODULE_DESCRIPTION("ARM AMBA serial port driver");
843 MODULE_LICENSE("GPL");
844