xref: /linux/drivers/tty/serial/amba-pl010.c (revision 7f71507851fc7764b36a3221839607d3a45c2025)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *  Driver for AMBA serial ports
4  *
5  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
6  *
7  *  Copyright 1999 ARM Limited
8  *  Copyright (C) 2000 Deep Blue Solutions Ltd.
9  *
10  * This is a generic driver for ARM AMBA-type serial ports.  They
11  * have a lot of 16550-like features, but are not register compatible.
12  * Note that although they do have CTS, DCD and DSR inputs, they do
13  * not have an RI input, nor do they have DTR or RTS outputs.  If
14  * required, these have to be supplied via some other means (eg, GPIO)
15  * and hooked into this driver.
16  */
17 
18 #include <linux/module.h>
19 #include <linux/ioport.h>
20 #include <linux/init.h>
21 #include <linux/console.h>
22 #include <linux/sysrq.h>
23 #include <linux/device.h>
24 #include <linux/tty.h>
25 #include <linux/tty_flip.h>
26 #include <linux/serial_core.h>
27 #include <linux/serial.h>
28 #include <linux/amba/bus.h>
29 #include <linux/amba/serial.h>
30 #include <linux/clk.h>
31 #include <linux/slab.h>
32 #include <linux/io.h>
33 
34 #define UART_NR		8
35 
36 #define SERIAL_AMBA_MAJOR	204
37 #define SERIAL_AMBA_MINOR	16
38 #define SERIAL_AMBA_NR		UART_NR
39 
40 #define AMBA_ISR_PASS_LIMIT	256
41 
42 #define UART_RX_DATA(s)		(((s) & UART01x_FR_RXFE) == 0)
43 #define UART_TX_READY(s)	(((s) & UART01x_FR_TXFF) == 0)
44 
45 #define UART_DUMMY_RSR_RX	256
46 #define UART_PORT_SIZE		64
47 
48 /*
49  * We wrap our port structure around the generic uart_port.
50  */
51 struct uart_amba_port {
52 	struct uart_port	port;
53 	struct clk		*clk;
54 	struct amba_device	*dev;
55 	struct amba_pl010_data	*data;
56 	unsigned int		old_status;
57 };
58 
59 static void pl010_stop_tx(struct uart_port *port)
60 {
61 	struct uart_amba_port *uap =
62 		container_of(port, struct uart_amba_port, port);
63 	unsigned int cr;
64 
65 	cr = readb(uap->port.membase + UART010_CR);
66 	cr &= ~UART010_CR_TIE;
67 	writel(cr, uap->port.membase + UART010_CR);
68 }
69 
70 static void pl010_start_tx(struct uart_port *port)
71 {
72 	struct uart_amba_port *uap =
73 		container_of(port, struct uart_amba_port, port);
74 	unsigned int cr;
75 
76 	cr = readb(uap->port.membase + UART010_CR);
77 	cr |= UART010_CR_TIE;
78 	writel(cr, uap->port.membase + UART010_CR);
79 }
80 
81 static void pl010_stop_rx(struct uart_port *port)
82 {
83 	struct uart_amba_port *uap =
84 		container_of(port, struct uart_amba_port, port);
85 	unsigned int cr;
86 
87 	cr = readb(uap->port.membase + UART010_CR);
88 	cr &= ~(UART010_CR_RIE | UART010_CR_RTIE);
89 	writel(cr, uap->port.membase + UART010_CR);
90 }
91 
92 static void pl010_disable_ms(struct uart_port *port)
93 {
94 	struct uart_amba_port *uap = (struct uart_amba_port *)port;
95 	unsigned int cr;
96 
97 	cr = readb(uap->port.membase + UART010_CR);
98 	cr &= ~UART010_CR_MSIE;
99 	writel(cr, uap->port.membase + UART010_CR);
100 }
101 
102 static void pl010_enable_ms(struct uart_port *port)
103 {
104 	struct uart_amba_port *uap =
105 		container_of(port, struct uart_amba_port, port);
106 	unsigned int cr;
107 
108 	cr = readb(uap->port.membase + UART010_CR);
109 	cr |= UART010_CR_MSIE;
110 	writel(cr, uap->port.membase + UART010_CR);
111 }
112 
113 static void pl010_rx_chars(struct uart_port *port)
114 {
115 	unsigned int status, rsr, max_count = 256;
116 	u8 ch, flag;
117 
118 	status = readb(port->membase + UART01x_FR);
119 	while (UART_RX_DATA(status) && max_count--) {
120 		ch = readb(port->membase + UART01x_DR);
121 		flag = TTY_NORMAL;
122 
123 		port->icount.rx++;
124 
125 		/*
126 		 * Note that the error handling code is
127 		 * out of the main execution path
128 		 */
129 		rsr = readb(port->membase + UART01x_RSR) | UART_DUMMY_RSR_RX;
130 		if (unlikely(rsr & UART01x_RSR_ANY)) {
131 			writel(0, port->membase + UART01x_ECR);
132 
133 			if (rsr & UART01x_RSR_BE) {
134 				rsr &= ~(UART01x_RSR_FE | UART01x_RSR_PE);
135 				port->icount.brk++;
136 				if (uart_handle_break(port))
137 					goto ignore_char;
138 			} else if (rsr & UART01x_RSR_PE)
139 				port->icount.parity++;
140 			else if (rsr & UART01x_RSR_FE)
141 				port->icount.frame++;
142 			if (rsr & UART01x_RSR_OE)
143 				port->icount.overrun++;
144 
145 			rsr &= port->read_status_mask;
146 
147 			if (rsr & UART01x_RSR_BE)
148 				flag = TTY_BREAK;
149 			else if (rsr & UART01x_RSR_PE)
150 				flag = TTY_PARITY;
151 			else if (rsr & UART01x_RSR_FE)
152 				flag = TTY_FRAME;
153 		}
154 
155 		if (uart_handle_sysrq_char(port, ch))
156 			goto ignore_char;
157 
158 		uart_insert_char(port, rsr, UART01x_RSR_OE, ch, flag);
159 
160 	ignore_char:
161 		status = readb(port->membase + UART01x_FR);
162 	}
163 	tty_flip_buffer_push(&port->state->port);
164 }
165 
166 static void pl010_tx_chars(struct uart_port *port)
167 {
168 	u8 ch;
169 
170 	uart_port_tx_limited(port, ch, port->fifosize >> 1,
171 		true,
172 		writel(ch, port->membase + UART01x_DR),
173 		({}));
174 }
175 
176 static void pl010_modem_status(struct uart_amba_port *uap)
177 {
178 	struct uart_port *port = &uap->port;
179 	unsigned int status, delta;
180 
181 	writel(0, port->membase + UART010_ICR);
182 
183 	status = readb(port->membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
184 
185 	delta = status ^ uap->old_status;
186 	uap->old_status = status;
187 
188 	if (!delta)
189 		return;
190 
191 	if (delta & UART01x_FR_DCD)
192 		uart_handle_dcd_change(port, status & UART01x_FR_DCD);
193 
194 	if (delta & UART01x_FR_DSR)
195 		port->icount.dsr++;
196 
197 	if (delta & UART01x_FR_CTS)
198 		uart_handle_cts_change(port, status & UART01x_FR_CTS);
199 
200 	wake_up_interruptible(&port->state->port.delta_msr_wait);
201 }
202 
203 static irqreturn_t pl010_int(int irq, void *dev_id)
204 {
205 	struct uart_amba_port *uap = dev_id;
206 	struct uart_port *port = &uap->port;
207 	unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
208 	int handled = 0;
209 
210 	uart_port_lock(port);
211 
212 	status = readb(port->membase + UART010_IIR);
213 	if (status) {
214 		do {
215 			if (status & (UART010_IIR_RTIS | UART010_IIR_RIS))
216 				pl010_rx_chars(port);
217 			if (status & UART010_IIR_MIS)
218 				pl010_modem_status(uap);
219 			if (status & UART010_IIR_TIS)
220 				pl010_tx_chars(port);
221 
222 			if (pass_counter-- == 0)
223 				break;
224 
225 			status = readb(port->membase + UART010_IIR);
226 		} while (status & (UART010_IIR_RTIS | UART010_IIR_RIS |
227 				   UART010_IIR_TIS));
228 		handled = 1;
229 	}
230 
231 	uart_port_unlock(port);
232 
233 	return IRQ_RETVAL(handled);
234 }
235 
236 static unsigned int pl010_tx_empty(struct uart_port *port)
237 {
238 	unsigned int status = readb(port->membase + UART01x_FR);
239 
240 	return status & UART01x_FR_BUSY ? 0 : TIOCSER_TEMT;
241 }
242 
243 static unsigned int pl010_get_mctrl(struct uart_port *port)
244 {
245 	unsigned int result = 0;
246 	unsigned int status;
247 
248 	status = readb(port->membase + UART01x_FR);
249 	if (status & UART01x_FR_DCD)
250 		result |= TIOCM_CAR;
251 	if (status & UART01x_FR_DSR)
252 		result |= TIOCM_DSR;
253 	if (status & UART01x_FR_CTS)
254 		result |= TIOCM_CTS;
255 
256 	return result;
257 }
258 
259 static void pl010_set_mctrl(struct uart_port *port, unsigned int mctrl)
260 {
261 	struct uart_amba_port *uap =
262 		container_of(port, struct uart_amba_port, port);
263 
264 	if (uap->data)
265 		uap->data->set_mctrl(uap->dev, port->membase, mctrl);
266 }
267 
268 static void pl010_break_ctl(struct uart_port *port, int break_state)
269 {
270 	unsigned long flags;
271 	unsigned int lcr_h;
272 
273 	uart_port_lock_irqsave(port, &flags);
274 	lcr_h = readb(port->membase + UART010_LCRH);
275 	if (break_state == -1)
276 		lcr_h |= UART01x_LCRH_BRK;
277 	else
278 		lcr_h &= ~UART01x_LCRH_BRK;
279 	writel(lcr_h, port->membase + UART010_LCRH);
280 	uart_port_unlock_irqrestore(port, flags);
281 }
282 
283 static int pl010_startup(struct uart_port *port)
284 {
285 	struct uart_amba_port *uap =
286 		container_of(port, struct uart_amba_port, port);
287 	int retval;
288 
289 	/*
290 	 * Try to enable the clock producer.
291 	 */
292 	retval = clk_prepare_enable(uap->clk);
293 	if (retval)
294 		goto out;
295 
296 	port->uartclk = clk_get_rate(uap->clk);
297 
298 	/*
299 	 * Allocate the IRQ
300 	 */
301 	retval = request_irq(port->irq, pl010_int, 0, "uart-pl010", uap);
302 	if (retval)
303 		goto clk_dis;
304 
305 	/*
306 	 * initialise the old status of the modem signals
307 	 */
308 	uap->old_status = readb(port->membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
309 
310 	/*
311 	 * Finally, enable interrupts
312 	 */
313 	writel(UART01x_CR_UARTEN | UART010_CR_RIE | UART010_CR_RTIE,
314 	       port->membase + UART010_CR);
315 
316 	return 0;
317 
318  clk_dis:
319 	clk_disable_unprepare(uap->clk);
320  out:
321 	return retval;
322 }
323 
324 static void pl010_shutdown(struct uart_port *port)
325 {
326 	struct uart_amba_port *uap =
327 		container_of(port, struct uart_amba_port, port);
328 
329 	/*
330 	 * Free the interrupt
331 	 */
332 	free_irq(port->irq, uap);
333 
334 	/*
335 	 * disable all interrupts, disable the port
336 	 */
337 	writel(0, port->membase + UART010_CR);
338 
339 	/* disable break condition and fifos */
340 	writel(readb(port->membase + UART010_LCRH) &
341 		~(UART01x_LCRH_BRK | UART01x_LCRH_FEN),
342 	       port->membase + UART010_LCRH);
343 
344 	/*
345 	 * Shut down the clock producer
346 	 */
347 	clk_disable_unprepare(uap->clk);
348 }
349 
350 static void
351 pl010_set_termios(struct uart_port *port, struct ktermios *termios,
352 		  const struct ktermios *old)
353 {
354 	unsigned int lcr_h, old_cr;
355 	unsigned long flags;
356 	unsigned int baud, quot;
357 
358 	/*
359 	 * Ask the core to calculate the divisor for us.
360 	 */
361 	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
362 	quot = uart_get_divisor(port, baud);
363 
364 	switch (termios->c_cflag & CSIZE) {
365 	case CS5:
366 		lcr_h = UART01x_LCRH_WLEN_5;
367 		break;
368 	case CS6:
369 		lcr_h = UART01x_LCRH_WLEN_6;
370 		break;
371 	case CS7:
372 		lcr_h = UART01x_LCRH_WLEN_7;
373 		break;
374 	default: // CS8
375 		lcr_h = UART01x_LCRH_WLEN_8;
376 		break;
377 	}
378 	if (termios->c_cflag & CSTOPB)
379 		lcr_h |= UART01x_LCRH_STP2;
380 	if (termios->c_cflag & PARENB) {
381 		lcr_h |= UART01x_LCRH_PEN;
382 		if (!(termios->c_cflag & PARODD))
383 			lcr_h |= UART01x_LCRH_EPS;
384 	}
385 	if (port->fifosize > 1)
386 		lcr_h |= UART01x_LCRH_FEN;
387 
388 	uart_port_lock_irqsave(port, &flags);
389 
390 	/*
391 	 * Update the per-port timeout.
392 	 */
393 	uart_update_timeout(port, termios->c_cflag, baud);
394 
395 	port->read_status_mask = UART01x_RSR_OE;
396 	if (termios->c_iflag & INPCK)
397 		port->read_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
398 	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
399 		port->read_status_mask |= UART01x_RSR_BE;
400 
401 	/*
402 	 * Characters to ignore
403 	 */
404 	port->ignore_status_mask = 0;
405 	if (termios->c_iflag & IGNPAR)
406 		port->ignore_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
407 	if (termios->c_iflag & IGNBRK) {
408 		port->ignore_status_mask |= UART01x_RSR_BE;
409 		/*
410 		 * If we're ignoring parity and break indicators,
411 		 * ignore overruns too (for real raw support).
412 		 */
413 		if (termios->c_iflag & IGNPAR)
414 			port->ignore_status_mask |= UART01x_RSR_OE;
415 	}
416 
417 	/*
418 	 * Ignore all characters if CREAD is not set.
419 	 */
420 	if ((termios->c_cflag & CREAD) == 0)
421 		port->ignore_status_mask |= UART_DUMMY_RSR_RX;
422 
423 	old_cr = readb(port->membase + UART010_CR) & ~UART010_CR_MSIE;
424 
425 	if (UART_ENABLE_MS(port, termios->c_cflag))
426 		old_cr |= UART010_CR_MSIE;
427 
428 	/* Set baud rate */
429 	quot -= 1;
430 	writel((quot & 0xf00) >> 8, port->membase + UART010_LCRM);
431 	writel(quot & 0xff, port->membase + UART010_LCRL);
432 
433 	/*
434 	 * ----------v----------v----------v----------v-----
435 	 * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
436 	 * ----------^----------^----------^----------^-----
437 	 */
438 	writel(lcr_h, port->membase + UART010_LCRH);
439 	writel(old_cr, port->membase + UART010_CR);
440 
441 	uart_port_unlock_irqrestore(port, flags);
442 }
443 
444 static void pl010_set_ldisc(struct uart_port *port, struct ktermios *termios)
445 {
446 	if (termios->c_line == N_PPS) {
447 		port->flags |= UPF_HARDPPS_CD;
448 		uart_port_lock_irq(port);
449 		pl010_enable_ms(port);
450 		uart_port_unlock_irq(port);
451 	} else {
452 		port->flags &= ~UPF_HARDPPS_CD;
453 		if (!UART_ENABLE_MS(port, termios->c_cflag)) {
454 			uart_port_lock_irq(port);
455 			pl010_disable_ms(port);
456 			uart_port_unlock_irq(port);
457 		}
458 	}
459 }
460 
461 static const char *pl010_type(struct uart_port *port)
462 {
463 	return port->type == PORT_AMBA ? "AMBA" : NULL;
464 }
465 
466 /*
467  * Release the memory region(s) being used by 'port'
468  */
469 static void pl010_release_port(struct uart_port *port)
470 {
471 	release_mem_region(port->mapbase, UART_PORT_SIZE);
472 }
473 
474 /*
475  * Request the memory region(s) being used by 'port'
476  */
477 static int pl010_request_port(struct uart_port *port)
478 {
479 	return request_mem_region(port->mapbase, UART_PORT_SIZE, "uart-pl010")
480 			!= NULL ? 0 : -EBUSY;
481 }
482 
483 /*
484  * Configure/autoconfigure the port.
485  */
486 static void pl010_config_port(struct uart_port *port, int flags)
487 {
488 	if (flags & UART_CONFIG_TYPE) {
489 		port->type = PORT_AMBA;
490 		pl010_request_port(port);
491 	}
492 }
493 
494 /*
495  * verify the new serial_struct (for TIOCSSERIAL).
496  */
497 static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser)
498 {
499 	int ret = 0;
500 	if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
501 		ret = -EINVAL;
502 	if (ser->irq < 0 || ser->irq >= irq_get_nr_irqs())
503 		ret = -EINVAL;
504 	if (ser->baud_base < 9600)
505 		ret = -EINVAL;
506 	return ret;
507 }
508 
509 static const struct uart_ops amba_pl010_pops = {
510 	.tx_empty	= pl010_tx_empty,
511 	.set_mctrl	= pl010_set_mctrl,
512 	.get_mctrl	= pl010_get_mctrl,
513 	.stop_tx	= pl010_stop_tx,
514 	.start_tx	= pl010_start_tx,
515 	.stop_rx	= pl010_stop_rx,
516 	.enable_ms	= pl010_enable_ms,
517 	.break_ctl	= pl010_break_ctl,
518 	.startup	= pl010_startup,
519 	.shutdown	= pl010_shutdown,
520 	.set_termios	= pl010_set_termios,
521 	.set_ldisc	= pl010_set_ldisc,
522 	.type		= pl010_type,
523 	.release_port	= pl010_release_port,
524 	.request_port	= pl010_request_port,
525 	.config_port	= pl010_config_port,
526 	.verify_port	= pl010_verify_port,
527 };
528 
529 static struct uart_amba_port *amba_ports[UART_NR];
530 
531 #ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE
532 
533 static void pl010_console_putchar(struct uart_port *port, unsigned char ch)
534 {
535 	unsigned int status;
536 
537 	do {
538 		status = readb(port->membase + UART01x_FR);
539 		barrier();
540 	} while (!UART_TX_READY(status));
541 	writel(ch, port->membase + UART01x_DR);
542 }
543 
544 static void
545 pl010_console_write(struct console *co, const char *s, unsigned int count)
546 {
547 	struct uart_amba_port *uap = amba_ports[co->index];
548 	struct uart_port *port = &uap->port;
549 	unsigned int status, old_cr;
550 
551 	clk_enable(uap->clk);
552 
553 	/*
554 	 *	First save the CR then disable the interrupts
555 	 */
556 	old_cr = readb(port->membase + UART010_CR);
557 	writel(UART01x_CR_UARTEN, port->membase + UART010_CR);
558 
559 	uart_console_write(port, s, count, pl010_console_putchar);
560 
561 	/*
562 	 *	Finally, wait for transmitter to become empty
563 	 *	and restore the TCR
564 	 */
565 	do {
566 		status = readb(port->membase + UART01x_FR);
567 		barrier();
568 	} while (status & UART01x_FR_BUSY);
569 	writel(old_cr, port->membase + UART010_CR);
570 
571 	clk_disable(uap->clk);
572 }
573 
574 static void __init
575 pl010_console_get_options(struct uart_amba_port *uap, int *baud,
576 			     int *parity, int *bits)
577 {
578 	if (readb(uap->port.membase + UART010_CR) & UART01x_CR_UARTEN) {
579 		unsigned int lcr_h, quot;
580 		lcr_h = readb(uap->port.membase + UART010_LCRH);
581 
582 		*parity = 'n';
583 		if (lcr_h & UART01x_LCRH_PEN) {
584 			if (lcr_h & UART01x_LCRH_EPS)
585 				*parity = 'e';
586 			else
587 				*parity = 'o';
588 		}
589 
590 		if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
591 			*bits = 7;
592 		else
593 			*bits = 8;
594 
595 		quot = readb(uap->port.membase + UART010_LCRL) |
596 		       readb(uap->port.membase + UART010_LCRM) << 8;
597 		*baud = uap->port.uartclk / (16 * (quot + 1));
598 	}
599 }
600 
601 static int __init pl010_console_setup(struct console *co, char *options)
602 {
603 	struct uart_amba_port *uap;
604 	int baud = 38400;
605 	int bits = 8;
606 	int parity = 'n';
607 	int flow = 'n';
608 	int ret;
609 
610 	/*
611 	 * Check whether an invalid uart number has been specified, and
612 	 * if so, search for the first available port that does have
613 	 * console support.
614 	 */
615 	if (co->index >= UART_NR)
616 		co->index = 0;
617 	uap = amba_ports[co->index];
618 	if (!uap)
619 		return -ENODEV;
620 
621 	ret = clk_prepare(uap->clk);
622 	if (ret)
623 		return ret;
624 
625 	uap->port.uartclk = clk_get_rate(uap->clk);
626 
627 	if (options)
628 		uart_parse_options(options, &baud, &parity, &bits, &flow);
629 	else
630 		pl010_console_get_options(uap, &baud, &parity, &bits);
631 
632 	return uart_set_options(&uap->port, co, baud, parity, bits, flow);
633 }
634 
635 static struct uart_driver amba_reg;
636 static struct console amba_console = {
637 	.name		= "ttyAM",
638 	.write		= pl010_console_write,
639 	.device		= uart_console_device,
640 	.setup		= pl010_console_setup,
641 	.flags		= CON_PRINTBUFFER,
642 	.index		= -1,
643 	.data		= &amba_reg,
644 };
645 
646 #define AMBA_CONSOLE	&amba_console
647 #else
648 #define AMBA_CONSOLE	NULL
649 #endif
650 
651 static DEFINE_MUTEX(amba_reg_lock);
652 static struct uart_driver amba_reg = {
653 	.owner			= THIS_MODULE,
654 	.driver_name		= "ttyAM",
655 	.dev_name		= "ttyAM",
656 	.major			= SERIAL_AMBA_MAJOR,
657 	.minor			= SERIAL_AMBA_MINOR,
658 	.nr			= UART_NR,
659 	.cons			= AMBA_CONSOLE,
660 };
661 
662 static int pl010_probe(struct amba_device *dev, const struct amba_id *id)
663 {
664 	struct uart_amba_port *uap;
665 	void __iomem *base;
666 	int i, ret;
667 
668 	for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
669 		if (amba_ports[i] == NULL)
670 			break;
671 
672 	if (i == ARRAY_SIZE(amba_ports))
673 		return -EBUSY;
674 
675 	uap = devm_kzalloc(&dev->dev, sizeof(struct uart_amba_port),
676 			   GFP_KERNEL);
677 	if (!uap)
678 		return -ENOMEM;
679 
680 	base = devm_ioremap(&dev->dev, dev->res.start,
681 			    resource_size(&dev->res));
682 	if (!base)
683 		return -ENOMEM;
684 
685 	uap->clk = devm_clk_get(&dev->dev, NULL);
686 	if (IS_ERR(uap->clk))
687 		return PTR_ERR(uap->clk);
688 
689 	uap->port.dev = &dev->dev;
690 	uap->port.mapbase = dev->res.start;
691 	uap->port.membase = base;
692 	uap->port.iotype = UPIO_MEM;
693 	uap->port.irq = dev->irq[0];
694 	uap->port.fifosize = 16;
695 	uap->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_AMBA_PL010_CONSOLE);
696 	uap->port.ops = &amba_pl010_pops;
697 	uap->port.flags = UPF_BOOT_AUTOCONF;
698 	uap->port.line = i;
699 	uap->dev = dev;
700 	uap->data = dev_get_platdata(&dev->dev);
701 
702 	amba_ports[i] = uap;
703 
704 	amba_set_drvdata(dev, uap);
705 
706 	mutex_lock(&amba_reg_lock);
707 	if (!amba_reg.state) {
708 		ret = uart_register_driver(&amba_reg);
709 		if (ret < 0) {
710 			mutex_unlock(&amba_reg_lock);
711 			dev_err(uap->port.dev,
712 				"Failed to register AMBA-PL010 driver\n");
713 			return ret;
714 		}
715 	}
716 	mutex_unlock(&amba_reg_lock);
717 
718 	ret = uart_add_one_port(&amba_reg, &uap->port);
719 	if (ret)
720 		amba_ports[i] = NULL;
721 
722 	return ret;
723 }
724 
725 static void pl010_remove(struct amba_device *dev)
726 {
727 	struct uart_amba_port *uap = amba_get_drvdata(dev);
728 	int i;
729 	bool busy = false;
730 
731 	uart_remove_one_port(&amba_reg, &uap->port);
732 
733 	for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
734 		if (amba_ports[i] == uap)
735 			amba_ports[i] = NULL;
736 		else if (amba_ports[i])
737 			busy = true;
738 
739 	if (!busy)
740 		uart_unregister_driver(&amba_reg);
741 }
742 
743 #ifdef CONFIG_PM_SLEEP
744 static int pl010_suspend(struct device *dev)
745 {
746 	struct uart_amba_port *uap = dev_get_drvdata(dev);
747 
748 	if (uap)
749 		uart_suspend_port(&amba_reg, &uap->port);
750 
751 	return 0;
752 }
753 
754 static int pl010_resume(struct device *dev)
755 {
756 	struct uart_amba_port *uap = dev_get_drvdata(dev);
757 
758 	if (uap)
759 		uart_resume_port(&amba_reg, &uap->port);
760 
761 	return 0;
762 }
763 #endif
764 
765 static SIMPLE_DEV_PM_OPS(pl010_dev_pm_ops, pl010_suspend, pl010_resume);
766 
767 static const struct amba_id pl010_ids[] = {
768 	{
769 		.id	= 0x00041010,
770 		.mask	= 0x000fffff,
771 	},
772 	{ 0, 0 },
773 };
774 
775 MODULE_DEVICE_TABLE(amba, pl010_ids);
776 
777 static struct amba_driver pl010_driver = {
778 	.drv = {
779 		.name	= "uart-pl010",
780 		.pm	= &pl010_dev_pm_ops,
781 	},
782 	.id_table	= pl010_ids,
783 	.probe		= pl010_probe,
784 	.remove		= pl010_remove,
785 };
786 
787 static int __init pl010_init(void)
788 {
789 	printk(KERN_INFO "Serial: AMBA driver\n");
790 
791 	return  amba_driver_register(&pl010_driver);
792 }
793 
794 static void __exit pl010_exit(void)
795 {
796 	amba_driver_unregister(&pl010_driver);
797 }
798 
799 module_init(pl010_init);
800 module_exit(pl010_exit);
801 
802 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
803 MODULE_DESCRIPTION("ARM AMBA serial port driver");
804 MODULE_LICENSE("GPL");
805