xref: /openbmc/linux/drivers/tty/serial/amba-pl010.c (revision 4800cd83)
1 /*
2  *  linux/drivers/char/amba.c
3  *
4  *  Driver for AMBA serial ports
5  *
6  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
7  *
8  *  Copyright 1999 ARM Limited
9  *  Copyright (C) 2000 Deep Blue Solutions Ltd.
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
24  *
25  * This is a generic driver for ARM AMBA-type serial ports.  They
26  * have a lot of 16550-like features, but are not register compatible.
27  * Note that although they do have CTS, DCD and DSR inputs, they do
28  * not have an RI input, nor do they have DTR or RTS outputs.  If
29  * required, these have to be supplied via some other means (eg, GPIO)
30  * and hooked into this driver.
31  */
32 
33 #if defined(CONFIG_SERIAL_AMBA_PL010_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
34 #define SUPPORT_SYSRQ
35 #endif
36 
37 #include <linux/module.h>
38 #include <linux/ioport.h>
39 #include <linux/init.h>
40 #include <linux/console.h>
41 #include <linux/sysrq.h>
42 #include <linux/device.h>
43 #include <linux/tty.h>
44 #include <linux/tty_flip.h>
45 #include <linux/serial_core.h>
46 #include <linux/serial.h>
47 #include <linux/amba/bus.h>
48 #include <linux/amba/serial.h>
49 #include <linux/clk.h>
50 #include <linux/slab.h>
51 
52 #include <asm/io.h>
53 
54 #define UART_NR		8
55 
56 #define SERIAL_AMBA_MAJOR	204
57 #define SERIAL_AMBA_MINOR	16
58 #define SERIAL_AMBA_NR		UART_NR
59 
60 #define AMBA_ISR_PASS_LIMIT	256
61 
62 #define UART_RX_DATA(s)		(((s) & UART01x_FR_RXFE) == 0)
63 #define UART_TX_READY(s)	(((s) & UART01x_FR_TXFF) == 0)
64 
65 #define UART_DUMMY_RSR_RX	256
66 #define UART_PORT_SIZE		64
67 
68 /*
69  * We wrap our port structure around the generic uart_port.
70  */
71 struct uart_amba_port {
72 	struct uart_port	port;
73 	struct clk		*clk;
74 	struct amba_device	*dev;
75 	struct amba_pl010_data	*data;
76 	unsigned int		old_status;
77 };
78 
79 static void pl010_stop_tx(struct uart_port *port)
80 {
81 	struct uart_amba_port *uap = (struct uart_amba_port *)port;
82 	unsigned int cr;
83 
84 	cr = readb(uap->port.membase + UART010_CR);
85 	cr &= ~UART010_CR_TIE;
86 	writel(cr, uap->port.membase + UART010_CR);
87 }
88 
89 static void pl010_start_tx(struct uart_port *port)
90 {
91 	struct uart_amba_port *uap = (struct uart_amba_port *)port;
92 	unsigned int cr;
93 
94 	cr = readb(uap->port.membase + UART010_CR);
95 	cr |= UART010_CR_TIE;
96 	writel(cr, uap->port.membase + UART010_CR);
97 }
98 
99 static void pl010_stop_rx(struct uart_port *port)
100 {
101 	struct uart_amba_port *uap = (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_enable_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_rx_chars(struct uart_amba_port *uap)
120 {
121 	struct tty_struct *tty = uap->port.state->port.tty;
122 	unsigned int status, ch, flag, rsr, max_count = 256;
123 
124 	status = readb(uap->port.membase + UART01x_FR);
125 	while (UART_RX_DATA(status) && max_count--) {
126 		ch = readb(uap->port.membase + UART01x_DR);
127 		flag = TTY_NORMAL;
128 
129 		uap->port.icount.rx++;
130 
131 		/*
132 		 * Note that the error handling code is
133 		 * out of the main execution path
134 		 */
135 		rsr = readb(uap->port.membase + UART01x_RSR) | UART_DUMMY_RSR_RX;
136 		if (unlikely(rsr & UART01x_RSR_ANY)) {
137 			writel(0, uap->port.membase + UART01x_ECR);
138 
139 			if (rsr & UART01x_RSR_BE) {
140 				rsr &= ~(UART01x_RSR_FE | UART01x_RSR_PE);
141 				uap->port.icount.brk++;
142 				if (uart_handle_break(&uap->port))
143 					goto ignore_char;
144 			} else if (rsr & UART01x_RSR_PE)
145 				uap->port.icount.parity++;
146 			else if (rsr & UART01x_RSR_FE)
147 				uap->port.icount.frame++;
148 			if (rsr & UART01x_RSR_OE)
149 				uap->port.icount.overrun++;
150 
151 			rsr &= uap->port.read_status_mask;
152 
153 			if (rsr & UART01x_RSR_BE)
154 				flag = TTY_BREAK;
155 			else if (rsr & UART01x_RSR_PE)
156 				flag = TTY_PARITY;
157 			else if (rsr & UART01x_RSR_FE)
158 				flag = TTY_FRAME;
159 		}
160 
161 		if (uart_handle_sysrq_char(&uap->port, ch))
162 			goto ignore_char;
163 
164 		uart_insert_char(&uap->port, rsr, UART01x_RSR_OE, ch, flag);
165 
166 	ignore_char:
167 		status = readb(uap->port.membase + UART01x_FR);
168 	}
169 	spin_unlock(&uap->port.lock);
170 	tty_flip_buffer_push(tty);
171 	spin_lock(&uap->port.lock);
172 }
173 
174 static void pl010_tx_chars(struct uart_amba_port *uap)
175 {
176 	struct circ_buf *xmit = &uap->port.state->xmit;
177 	int count;
178 
179 	if (uap->port.x_char) {
180 		writel(uap->port.x_char, uap->port.membase + UART01x_DR);
181 		uap->port.icount.tx++;
182 		uap->port.x_char = 0;
183 		return;
184 	}
185 	if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) {
186 		pl010_stop_tx(&uap->port);
187 		return;
188 	}
189 
190 	count = uap->port.fifosize >> 1;
191 	do {
192 		writel(xmit->buf[xmit->tail], uap->port.membase + UART01x_DR);
193 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
194 		uap->port.icount.tx++;
195 		if (uart_circ_empty(xmit))
196 			break;
197 	} while (--count > 0);
198 
199 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
200 		uart_write_wakeup(&uap->port);
201 
202 	if (uart_circ_empty(xmit))
203 		pl010_stop_tx(&uap->port);
204 }
205 
206 static void pl010_modem_status(struct uart_amba_port *uap)
207 {
208 	unsigned int status, delta;
209 
210 	writel(0, uap->port.membase + UART010_ICR);
211 
212 	status = readb(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
213 
214 	delta = status ^ uap->old_status;
215 	uap->old_status = status;
216 
217 	if (!delta)
218 		return;
219 
220 	if (delta & UART01x_FR_DCD)
221 		uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD);
222 
223 	if (delta & UART01x_FR_DSR)
224 		uap->port.icount.dsr++;
225 
226 	if (delta & UART01x_FR_CTS)
227 		uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS);
228 
229 	wake_up_interruptible(&uap->port.state->port.delta_msr_wait);
230 }
231 
232 static irqreturn_t pl010_int(int irq, void *dev_id)
233 {
234 	struct uart_amba_port *uap = dev_id;
235 	unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
236 	int handled = 0;
237 
238 	spin_lock(&uap->port.lock);
239 
240 	status = readb(uap->port.membase + UART010_IIR);
241 	if (status) {
242 		do {
243 			if (status & (UART010_IIR_RTIS | UART010_IIR_RIS))
244 				pl010_rx_chars(uap);
245 			if (status & UART010_IIR_MIS)
246 				pl010_modem_status(uap);
247 			if (status & UART010_IIR_TIS)
248 				pl010_tx_chars(uap);
249 
250 			if (pass_counter-- == 0)
251 				break;
252 
253 			status = readb(uap->port.membase + UART010_IIR);
254 		} while (status & (UART010_IIR_RTIS | UART010_IIR_RIS |
255 				   UART010_IIR_TIS));
256 		handled = 1;
257 	}
258 
259 	spin_unlock(&uap->port.lock);
260 
261 	return IRQ_RETVAL(handled);
262 }
263 
264 static unsigned int pl010_tx_empty(struct uart_port *port)
265 {
266 	struct uart_amba_port *uap = (struct uart_amba_port *)port;
267 	unsigned int status = readb(uap->port.membase + UART01x_FR);
268 	return status & UART01x_FR_BUSY ? 0 : TIOCSER_TEMT;
269 }
270 
271 static unsigned int pl010_get_mctrl(struct uart_port *port)
272 {
273 	struct uart_amba_port *uap = (struct uart_amba_port *)port;
274 	unsigned int result = 0;
275 	unsigned int status;
276 
277 	status = readb(uap->port.membase + UART01x_FR);
278 	if (status & UART01x_FR_DCD)
279 		result |= TIOCM_CAR;
280 	if (status & UART01x_FR_DSR)
281 		result |= TIOCM_DSR;
282 	if (status & UART01x_FR_CTS)
283 		result |= TIOCM_CTS;
284 
285 	return result;
286 }
287 
288 static void pl010_set_mctrl(struct uart_port *port, unsigned int mctrl)
289 {
290 	struct uart_amba_port *uap = (struct uart_amba_port *)port;
291 
292 	if (uap->data)
293 		uap->data->set_mctrl(uap->dev, uap->port.membase, mctrl);
294 }
295 
296 static void pl010_break_ctl(struct uart_port *port, int break_state)
297 {
298 	struct uart_amba_port *uap = (struct uart_amba_port *)port;
299 	unsigned long flags;
300 	unsigned int lcr_h;
301 
302 	spin_lock_irqsave(&uap->port.lock, flags);
303 	lcr_h = readb(uap->port.membase + UART010_LCRH);
304 	if (break_state == -1)
305 		lcr_h |= UART01x_LCRH_BRK;
306 	else
307 		lcr_h &= ~UART01x_LCRH_BRK;
308 	writel(lcr_h, uap->port.membase + UART010_LCRH);
309 	spin_unlock_irqrestore(&uap->port.lock, flags);
310 }
311 
312 static int pl010_startup(struct uart_port *port)
313 {
314 	struct uart_amba_port *uap = (struct uart_amba_port *)port;
315 	int retval;
316 
317 	/*
318 	 * Try to enable the clock producer.
319 	 */
320 	retval = clk_enable(uap->clk);
321 	if (retval)
322 		goto out;
323 
324 	uap->port.uartclk = clk_get_rate(uap->clk);
325 
326 	/*
327 	 * Allocate the IRQ
328 	 */
329 	retval = request_irq(uap->port.irq, pl010_int, 0, "uart-pl010", uap);
330 	if (retval)
331 		goto clk_dis;
332 
333 	/*
334 	 * initialise the old status of the modem signals
335 	 */
336 	uap->old_status = readb(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
337 
338 	/*
339 	 * Finally, enable interrupts
340 	 */
341 	writel(UART01x_CR_UARTEN | UART010_CR_RIE | UART010_CR_RTIE,
342 	       uap->port.membase + UART010_CR);
343 
344 	return 0;
345 
346  clk_dis:
347 	clk_disable(uap->clk);
348  out:
349 	return retval;
350 }
351 
352 static void pl010_shutdown(struct uart_port *port)
353 {
354 	struct uart_amba_port *uap = (struct uart_amba_port *)port;
355 
356 	/*
357 	 * Free the interrupt
358 	 */
359 	free_irq(uap->port.irq, uap);
360 
361 	/*
362 	 * disable all interrupts, disable the port
363 	 */
364 	writel(0, uap->port.membase + UART010_CR);
365 
366 	/* disable break condition and fifos */
367 	writel(readb(uap->port.membase + UART010_LCRH) &
368 		~(UART01x_LCRH_BRK | UART01x_LCRH_FEN),
369 	       uap->port.membase + UART010_LCRH);
370 
371 	/*
372 	 * Shut down the clock producer
373 	 */
374 	clk_disable(uap->clk);
375 }
376 
377 static void
378 pl010_set_termios(struct uart_port *port, struct ktermios *termios,
379 		     struct ktermios *old)
380 {
381 	struct uart_amba_port *uap = (struct uart_amba_port *)port;
382 	unsigned int lcr_h, old_cr;
383 	unsigned long flags;
384 	unsigned int baud, quot;
385 
386 	/*
387 	 * Ask the core to calculate the divisor for us.
388 	 */
389 	baud = uart_get_baud_rate(port, termios, old, 0, uap->port.uartclk/16);
390 	quot = uart_get_divisor(port, baud);
391 
392 	switch (termios->c_cflag & CSIZE) {
393 	case CS5:
394 		lcr_h = UART01x_LCRH_WLEN_5;
395 		break;
396 	case CS6:
397 		lcr_h = UART01x_LCRH_WLEN_6;
398 		break;
399 	case CS7:
400 		lcr_h = UART01x_LCRH_WLEN_7;
401 		break;
402 	default: // CS8
403 		lcr_h = UART01x_LCRH_WLEN_8;
404 		break;
405 	}
406 	if (termios->c_cflag & CSTOPB)
407 		lcr_h |= UART01x_LCRH_STP2;
408 	if (termios->c_cflag & PARENB) {
409 		lcr_h |= UART01x_LCRH_PEN;
410 		if (!(termios->c_cflag & PARODD))
411 			lcr_h |= UART01x_LCRH_EPS;
412 	}
413 	if (uap->port.fifosize > 1)
414 		lcr_h |= UART01x_LCRH_FEN;
415 
416 	spin_lock_irqsave(&uap->port.lock, flags);
417 
418 	/*
419 	 * Update the per-port timeout.
420 	 */
421 	uart_update_timeout(port, termios->c_cflag, baud);
422 
423 	uap->port.read_status_mask = UART01x_RSR_OE;
424 	if (termios->c_iflag & INPCK)
425 		uap->port.read_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
426 	if (termios->c_iflag & (BRKINT | PARMRK))
427 		uap->port.read_status_mask |= UART01x_RSR_BE;
428 
429 	/*
430 	 * Characters to ignore
431 	 */
432 	uap->port.ignore_status_mask = 0;
433 	if (termios->c_iflag & IGNPAR)
434 		uap->port.ignore_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
435 	if (termios->c_iflag & IGNBRK) {
436 		uap->port.ignore_status_mask |= UART01x_RSR_BE;
437 		/*
438 		 * If we're ignoring parity and break indicators,
439 		 * ignore overruns too (for real raw support).
440 		 */
441 		if (termios->c_iflag & IGNPAR)
442 			uap->port.ignore_status_mask |= UART01x_RSR_OE;
443 	}
444 
445 	/*
446 	 * Ignore all characters if CREAD is not set.
447 	 */
448 	if ((termios->c_cflag & CREAD) == 0)
449 		uap->port.ignore_status_mask |= UART_DUMMY_RSR_RX;
450 
451 	/* first, disable everything */
452 	old_cr = readb(uap->port.membase + UART010_CR) & ~UART010_CR_MSIE;
453 
454 	if (UART_ENABLE_MS(port, termios->c_cflag))
455 		old_cr |= UART010_CR_MSIE;
456 
457 	writel(0, uap->port.membase + UART010_CR);
458 
459 	/* Set baud rate */
460 	quot -= 1;
461 	writel((quot & 0xf00) >> 8, uap->port.membase + UART010_LCRM);
462 	writel(quot & 0xff, uap->port.membase + UART010_LCRL);
463 
464 	/*
465 	 * ----------v----------v----------v----------v-----
466 	 * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
467 	 * ----------^----------^----------^----------^-----
468 	 */
469 	writel(lcr_h, uap->port.membase + UART010_LCRH);
470 	writel(old_cr, uap->port.membase + UART010_CR);
471 
472 	spin_unlock_irqrestore(&uap->port.lock, flags);
473 }
474 
475 static void pl010_set_ldisc(struct uart_port *port, int new)
476 {
477 	if (new == N_PPS) {
478 		port->flags |= UPF_HARDPPS_CD;
479 		pl010_enable_ms(port);
480 	} else
481 		port->flags &= ~UPF_HARDPPS_CD;
482 }
483 
484 static const char *pl010_type(struct uart_port *port)
485 {
486 	return port->type == PORT_AMBA ? "AMBA" : NULL;
487 }
488 
489 /*
490  * Release the memory region(s) being used by 'port'
491  */
492 static void pl010_release_port(struct uart_port *port)
493 {
494 	release_mem_region(port->mapbase, UART_PORT_SIZE);
495 }
496 
497 /*
498  * Request the memory region(s) being used by 'port'
499  */
500 static int pl010_request_port(struct uart_port *port)
501 {
502 	return request_mem_region(port->mapbase, UART_PORT_SIZE, "uart-pl010")
503 			!= NULL ? 0 : -EBUSY;
504 }
505 
506 /*
507  * Configure/autoconfigure the port.
508  */
509 static void pl010_config_port(struct uart_port *port, int flags)
510 {
511 	if (flags & UART_CONFIG_TYPE) {
512 		port->type = PORT_AMBA;
513 		pl010_request_port(port);
514 	}
515 }
516 
517 /*
518  * verify the new serial_struct (for TIOCSSERIAL).
519  */
520 static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser)
521 {
522 	int ret = 0;
523 	if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
524 		ret = -EINVAL;
525 	if (ser->irq < 0 || ser->irq >= nr_irqs)
526 		ret = -EINVAL;
527 	if (ser->baud_base < 9600)
528 		ret = -EINVAL;
529 	return ret;
530 }
531 
532 static struct uart_ops amba_pl010_pops = {
533 	.tx_empty	= pl010_tx_empty,
534 	.set_mctrl	= pl010_set_mctrl,
535 	.get_mctrl	= pl010_get_mctrl,
536 	.stop_tx	= pl010_stop_tx,
537 	.start_tx	= pl010_start_tx,
538 	.stop_rx	= pl010_stop_rx,
539 	.enable_ms	= pl010_enable_ms,
540 	.break_ctl	= pl010_break_ctl,
541 	.startup	= pl010_startup,
542 	.shutdown	= pl010_shutdown,
543 	.set_termios	= pl010_set_termios,
544 	.set_ldisc	= pl010_set_ldisc,
545 	.type		= pl010_type,
546 	.release_port	= pl010_release_port,
547 	.request_port	= pl010_request_port,
548 	.config_port	= pl010_config_port,
549 	.verify_port	= pl010_verify_port,
550 };
551 
552 static struct uart_amba_port *amba_ports[UART_NR];
553 
554 #ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE
555 
556 static void pl010_console_putchar(struct uart_port *port, int ch)
557 {
558 	struct uart_amba_port *uap = (struct uart_amba_port *)port;
559 	unsigned int status;
560 
561 	do {
562 		status = readb(uap->port.membase + UART01x_FR);
563 		barrier();
564 	} while (!UART_TX_READY(status));
565 	writel(ch, uap->port.membase + UART01x_DR);
566 }
567 
568 static void
569 pl010_console_write(struct console *co, const char *s, unsigned int count)
570 {
571 	struct uart_amba_port *uap = amba_ports[co->index];
572 	unsigned int status, old_cr;
573 
574 	clk_enable(uap->clk);
575 
576 	/*
577 	 *	First save the CR then disable the interrupts
578 	 */
579 	old_cr = readb(uap->port.membase + UART010_CR);
580 	writel(UART01x_CR_UARTEN, uap->port.membase + UART010_CR);
581 
582 	uart_console_write(&uap->port, s, count, pl010_console_putchar);
583 
584 	/*
585 	 *	Finally, wait for transmitter to become empty
586 	 *	and restore the TCR
587 	 */
588 	do {
589 		status = readb(uap->port.membase + UART01x_FR);
590 		barrier();
591 	} while (status & UART01x_FR_BUSY);
592 	writel(old_cr, uap->port.membase + UART010_CR);
593 
594 	clk_disable(uap->clk);
595 }
596 
597 static void __init
598 pl010_console_get_options(struct uart_amba_port *uap, int *baud,
599 			     int *parity, int *bits)
600 {
601 	if (readb(uap->port.membase + UART010_CR) & UART01x_CR_UARTEN) {
602 		unsigned int lcr_h, quot;
603 		lcr_h = readb(uap->port.membase + UART010_LCRH);
604 
605 		*parity = 'n';
606 		if (lcr_h & UART01x_LCRH_PEN) {
607 			if (lcr_h & UART01x_LCRH_EPS)
608 				*parity = 'e';
609 			else
610 				*parity = 'o';
611 		}
612 
613 		if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
614 			*bits = 7;
615 		else
616 			*bits = 8;
617 
618 		quot = readb(uap->port.membase + UART010_LCRL) |
619 		       readb(uap->port.membase + UART010_LCRM) << 8;
620 		*baud = uap->port.uartclk / (16 * (quot + 1));
621 	}
622 }
623 
624 static int __init pl010_console_setup(struct console *co, char *options)
625 {
626 	struct uart_amba_port *uap;
627 	int baud = 38400;
628 	int bits = 8;
629 	int parity = 'n';
630 	int flow = 'n';
631 
632 	/*
633 	 * Check whether an invalid uart number has been specified, and
634 	 * if so, search for the first available port that does have
635 	 * console support.
636 	 */
637 	if (co->index >= UART_NR)
638 		co->index = 0;
639 	uap = amba_ports[co->index];
640 	if (!uap)
641 		return -ENODEV;
642 
643 	uap->port.uartclk = clk_get_rate(uap->clk);
644 
645 	if (options)
646 		uart_parse_options(options, &baud, &parity, &bits, &flow);
647 	else
648 		pl010_console_get_options(uap, &baud, &parity, &bits);
649 
650 	return uart_set_options(&uap->port, co, baud, parity, bits, flow);
651 }
652 
653 static struct uart_driver amba_reg;
654 static struct console amba_console = {
655 	.name		= "ttyAM",
656 	.write		= pl010_console_write,
657 	.device		= uart_console_device,
658 	.setup		= pl010_console_setup,
659 	.flags		= CON_PRINTBUFFER,
660 	.index		= -1,
661 	.data		= &amba_reg,
662 };
663 
664 #define AMBA_CONSOLE	&amba_console
665 #else
666 #define AMBA_CONSOLE	NULL
667 #endif
668 
669 static struct uart_driver amba_reg = {
670 	.owner			= THIS_MODULE,
671 	.driver_name		= "ttyAM",
672 	.dev_name		= "ttyAM",
673 	.major			= SERIAL_AMBA_MAJOR,
674 	.minor			= SERIAL_AMBA_MINOR,
675 	.nr			= UART_NR,
676 	.cons			= AMBA_CONSOLE,
677 };
678 
679 static int pl010_probe(struct amba_device *dev, struct amba_id *id)
680 {
681 	struct uart_amba_port *uap;
682 	void __iomem *base;
683 	int i, ret;
684 
685 	for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
686 		if (amba_ports[i] == NULL)
687 			break;
688 
689 	if (i == ARRAY_SIZE(amba_ports)) {
690 		ret = -EBUSY;
691 		goto out;
692 	}
693 
694 	uap = kzalloc(sizeof(struct uart_amba_port), GFP_KERNEL);
695 	if (!uap) {
696 		ret = -ENOMEM;
697 		goto out;
698 	}
699 
700 	base = ioremap(dev->res.start, resource_size(&dev->res));
701 	if (!base) {
702 		ret = -ENOMEM;
703 		goto free;
704 	}
705 
706 	uap->clk = clk_get(&dev->dev, NULL);
707 	if (IS_ERR(uap->clk)) {
708 		ret = PTR_ERR(uap->clk);
709 		goto unmap;
710 	}
711 
712 	uap->port.dev = &dev->dev;
713 	uap->port.mapbase = dev->res.start;
714 	uap->port.membase = base;
715 	uap->port.iotype = UPIO_MEM;
716 	uap->port.irq = dev->irq[0];
717 	uap->port.fifosize = 16;
718 	uap->port.ops = &amba_pl010_pops;
719 	uap->port.flags = UPF_BOOT_AUTOCONF;
720 	uap->port.line = i;
721 	uap->dev = dev;
722 	uap->data = dev->dev.platform_data;
723 
724 	amba_ports[i] = uap;
725 
726 	amba_set_drvdata(dev, uap);
727 	ret = uart_add_one_port(&amba_reg, &uap->port);
728 	if (ret) {
729 		amba_set_drvdata(dev, NULL);
730 		amba_ports[i] = NULL;
731 		clk_put(uap->clk);
732  unmap:
733 		iounmap(base);
734  free:
735 		kfree(uap);
736 	}
737  out:
738 	return ret;
739 }
740 
741 static int pl010_remove(struct amba_device *dev)
742 {
743 	struct uart_amba_port *uap = amba_get_drvdata(dev);
744 	int i;
745 
746 	amba_set_drvdata(dev, NULL);
747 
748 	uart_remove_one_port(&amba_reg, &uap->port);
749 
750 	for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
751 		if (amba_ports[i] == uap)
752 			amba_ports[i] = NULL;
753 
754 	iounmap(uap->port.membase);
755 	clk_put(uap->clk);
756 	kfree(uap);
757 	return 0;
758 }
759 
760 static int pl010_suspend(struct amba_device *dev, pm_message_t state)
761 {
762 	struct uart_amba_port *uap = amba_get_drvdata(dev);
763 
764 	if (uap)
765 		uart_suspend_port(&amba_reg, &uap->port);
766 
767 	return 0;
768 }
769 
770 static int pl010_resume(struct amba_device *dev)
771 {
772 	struct uart_amba_port *uap = amba_get_drvdata(dev);
773 
774 	if (uap)
775 		uart_resume_port(&amba_reg, &uap->port);
776 
777 	return 0;
778 }
779 
780 static struct amba_id pl010_ids[] = {
781 	{
782 		.id	= 0x00041010,
783 		.mask	= 0x000fffff,
784 	},
785 	{ 0, 0 },
786 };
787 
788 static struct amba_driver pl010_driver = {
789 	.drv = {
790 		.name	= "uart-pl010",
791 	},
792 	.id_table	= pl010_ids,
793 	.probe		= pl010_probe,
794 	.remove		= pl010_remove,
795 	.suspend	= pl010_suspend,
796 	.resume		= pl010_resume,
797 };
798 
799 static int __init pl010_init(void)
800 {
801 	int ret;
802 
803 	printk(KERN_INFO "Serial: AMBA driver\n");
804 
805 	ret = uart_register_driver(&amba_reg);
806 	if (ret == 0) {
807 		ret = amba_driver_register(&pl010_driver);
808 		if (ret)
809 			uart_unregister_driver(&amba_reg);
810 	}
811 	return ret;
812 }
813 
814 static void __exit pl010_exit(void)
815 {
816 	amba_driver_unregister(&pl010_driver);
817 	uart_unregister_driver(&amba_reg);
818 }
819 
820 module_init(pl010_init);
821 module_exit(pl010_exit);
822 
823 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
824 MODULE_DESCRIPTION("ARM AMBA serial port driver");
825 MODULE_LICENSE("GPL");
826