xref: /openbmc/linux/drivers/tty/serial/amba-pl010.c (revision 61f4d204)
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, ch, flag, rsr, max_count = 256;
116 
117 	status = readb(port->membase + UART01x_FR);
118 	while (UART_RX_DATA(status) && max_count--) {
119 		ch = readb(port->membase + UART01x_DR);
120 		flag = TTY_NORMAL;
121 
122 		port->icount.rx++;
123 
124 		/*
125 		 * Note that the error handling code is
126 		 * out of the main execution path
127 		 */
128 		rsr = readb(port->membase + UART01x_RSR) | UART_DUMMY_RSR_RX;
129 		if (unlikely(rsr & UART01x_RSR_ANY)) {
130 			writel(0, port->membase + UART01x_ECR);
131 
132 			if (rsr & UART01x_RSR_BE) {
133 				rsr &= ~(UART01x_RSR_FE | UART01x_RSR_PE);
134 				port->icount.brk++;
135 				if (uart_handle_break(port))
136 					goto ignore_char;
137 			} else if (rsr & UART01x_RSR_PE)
138 				port->icount.parity++;
139 			else if (rsr & UART01x_RSR_FE)
140 				port->icount.frame++;
141 			if (rsr & UART01x_RSR_OE)
142 				port->icount.overrun++;
143 
144 			rsr &= port->read_status_mask;
145 
146 			if (rsr & UART01x_RSR_BE)
147 				flag = TTY_BREAK;
148 			else if (rsr & UART01x_RSR_PE)
149 				flag = TTY_PARITY;
150 			else if (rsr & UART01x_RSR_FE)
151 				flag = TTY_FRAME;
152 		}
153 
154 		if (uart_handle_sysrq_char(port, ch))
155 			goto ignore_char;
156 
157 		uart_insert_char(port, rsr, UART01x_RSR_OE, ch, flag);
158 
159 	ignore_char:
160 		status = readb(port->membase + UART01x_FR);
161 	}
162 	tty_flip_buffer_push(&port->state->port);
163 }
164 
165 static void pl010_tx_chars(struct uart_port *port)
166 {
167 	u8 ch;
168 
169 	uart_port_tx_limited(port, ch, port->fifosize >> 1,
170 		true,
171 		writel(ch, port->membase + UART01x_DR),
172 		({}));
173 }
174 
175 static void pl010_modem_status(struct uart_amba_port *uap)
176 {
177 	struct uart_port *port = &uap->port;
178 	unsigned int status, delta;
179 
180 	writel(0, port->membase + UART010_ICR);
181 
182 	status = readb(port->membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
183 
184 	delta = status ^ uap->old_status;
185 	uap->old_status = status;
186 
187 	if (!delta)
188 		return;
189 
190 	if (delta & UART01x_FR_DCD)
191 		uart_handle_dcd_change(port, status & UART01x_FR_DCD);
192 
193 	if (delta & UART01x_FR_DSR)
194 		port->icount.dsr++;
195 
196 	if (delta & UART01x_FR_CTS)
197 		uart_handle_cts_change(port, status & UART01x_FR_CTS);
198 
199 	wake_up_interruptible(&port->state->port.delta_msr_wait);
200 }
201 
202 static irqreturn_t pl010_int(int irq, void *dev_id)
203 {
204 	struct uart_amba_port *uap = dev_id;
205 	struct uart_port *port = &uap->port;
206 	unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
207 	int handled = 0;
208 
209 	spin_lock(&port->lock);
210 
211 	status = readb(port->membase + UART010_IIR);
212 	if (status) {
213 		do {
214 			if (status & (UART010_IIR_RTIS | UART010_IIR_RIS))
215 				pl010_rx_chars(port);
216 			if (status & UART010_IIR_MIS)
217 				pl010_modem_status(uap);
218 			if (status & UART010_IIR_TIS)
219 				pl010_tx_chars(port);
220 
221 			if (pass_counter-- == 0)
222 				break;
223 
224 			status = readb(port->membase + UART010_IIR);
225 		} while (status & (UART010_IIR_RTIS | UART010_IIR_RIS |
226 				   UART010_IIR_TIS));
227 		handled = 1;
228 	}
229 
230 	spin_unlock(&port->lock);
231 
232 	return IRQ_RETVAL(handled);
233 }
234 
235 static unsigned int pl010_tx_empty(struct uart_port *port)
236 {
237 	unsigned int status = readb(port->membase + UART01x_FR);
238 
239 	return status & UART01x_FR_BUSY ? 0 : TIOCSER_TEMT;
240 }
241 
242 static unsigned int pl010_get_mctrl(struct uart_port *port)
243 {
244 	unsigned int result = 0;
245 	unsigned int status;
246 
247 	status = readb(port->membase + UART01x_FR);
248 	if (status & UART01x_FR_DCD)
249 		result |= TIOCM_CAR;
250 	if (status & UART01x_FR_DSR)
251 		result |= TIOCM_DSR;
252 	if (status & UART01x_FR_CTS)
253 		result |= TIOCM_CTS;
254 
255 	return result;
256 }
257 
258 static void pl010_set_mctrl(struct uart_port *port, unsigned int mctrl)
259 {
260 	struct uart_amba_port *uap =
261 		container_of(port, struct uart_amba_port, port);
262 
263 	if (uap->data)
264 		uap->data->set_mctrl(uap->dev, port->membase, mctrl);
265 }
266 
267 static void pl010_break_ctl(struct uart_port *port, int break_state)
268 {
269 	unsigned long flags;
270 	unsigned int lcr_h;
271 
272 	spin_lock_irqsave(&port->lock, flags);
273 	lcr_h = readb(port->membase + UART010_LCRH);
274 	if (break_state == -1)
275 		lcr_h |= UART01x_LCRH_BRK;
276 	else
277 		lcr_h &= ~UART01x_LCRH_BRK;
278 	writel(lcr_h, port->membase + UART010_LCRH);
279 	spin_unlock_irqrestore(&port->lock, flags);
280 }
281 
282 static int pl010_startup(struct uart_port *port)
283 {
284 	struct uart_amba_port *uap =
285 		container_of(port, struct uart_amba_port, port);
286 	int retval;
287 
288 	/*
289 	 * Try to enable the clock producer.
290 	 */
291 	retval = clk_prepare_enable(uap->clk);
292 	if (retval)
293 		goto out;
294 
295 	port->uartclk = clk_get_rate(uap->clk);
296 
297 	/*
298 	 * Allocate the IRQ
299 	 */
300 	retval = request_irq(port->irq, pl010_int, 0, "uart-pl010", uap);
301 	if (retval)
302 		goto clk_dis;
303 
304 	/*
305 	 * initialise the old status of the modem signals
306 	 */
307 	uap->old_status = readb(port->membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
308 
309 	/*
310 	 * Finally, enable interrupts
311 	 */
312 	writel(UART01x_CR_UARTEN | UART010_CR_RIE | UART010_CR_RTIE,
313 	       port->membase + UART010_CR);
314 
315 	return 0;
316 
317  clk_dis:
318 	clk_disable_unprepare(uap->clk);
319  out:
320 	return retval;
321 }
322 
323 static void pl010_shutdown(struct uart_port *port)
324 {
325 	struct uart_amba_port *uap =
326 		container_of(port, struct uart_amba_port, port);
327 
328 	/*
329 	 * Free the interrupt
330 	 */
331 	free_irq(port->irq, uap);
332 
333 	/*
334 	 * disable all interrupts, disable the port
335 	 */
336 	writel(0, port->membase + UART010_CR);
337 
338 	/* disable break condition and fifos */
339 	writel(readb(port->membase + UART010_LCRH) &
340 		~(UART01x_LCRH_BRK | UART01x_LCRH_FEN),
341 	       port->membase + UART010_LCRH);
342 
343 	/*
344 	 * Shut down the clock producer
345 	 */
346 	clk_disable_unprepare(uap->clk);
347 }
348 
349 static void
350 pl010_set_termios(struct uart_port *port, struct ktermios *termios,
351 		  const struct ktermios *old)
352 {
353 	unsigned int lcr_h, old_cr;
354 	unsigned long flags;
355 	unsigned int baud, quot;
356 
357 	/*
358 	 * Ask the core to calculate the divisor for us.
359 	 */
360 	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
361 	quot = uart_get_divisor(port, baud);
362 
363 	switch (termios->c_cflag & CSIZE) {
364 	case CS5:
365 		lcr_h = UART01x_LCRH_WLEN_5;
366 		break;
367 	case CS6:
368 		lcr_h = UART01x_LCRH_WLEN_6;
369 		break;
370 	case CS7:
371 		lcr_h = UART01x_LCRH_WLEN_7;
372 		break;
373 	default: // CS8
374 		lcr_h = UART01x_LCRH_WLEN_8;
375 		break;
376 	}
377 	if (termios->c_cflag & CSTOPB)
378 		lcr_h |= UART01x_LCRH_STP2;
379 	if (termios->c_cflag & PARENB) {
380 		lcr_h |= UART01x_LCRH_PEN;
381 		if (!(termios->c_cflag & PARODD))
382 			lcr_h |= UART01x_LCRH_EPS;
383 	}
384 	if (port->fifosize > 1)
385 		lcr_h |= UART01x_LCRH_FEN;
386 
387 	spin_lock_irqsave(&port->lock, flags);
388 
389 	/*
390 	 * Update the per-port timeout.
391 	 */
392 	uart_update_timeout(port, termios->c_cflag, baud);
393 
394 	port->read_status_mask = UART01x_RSR_OE;
395 	if (termios->c_iflag & INPCK)
396 		port->read_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
397 	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
398 		port->read_status_mask |= UART01x_RSR_BE;
399 
400 	/*
401 	 * Characters to ignore
402 	 */
403 	port->ignore_status_mask = 0;
404 	if (termios->c_iflag & IGNPAR)
405 		port->ignore_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
406 	if (termios->c_iflag & IGNBRK) {
407 		port->ignore_status_mask |= UART01x_RSR_BE;
408 		/*
409 		 * If we're ignoring parity and break indicators,
410 		 * ignore overruns too (for real raw support).
411 		 */
412 		if (termios->c_iflag & IGNPAR)
413 			port->ignore_status_mask |= UART01x_RSR_OE;
414 	}
415 
416 	/*
417 	 * Ignore all characters if CREAD is not set.
418 	 */
419 	if ((termios->c_cflag & CREAD) == 0)
420 		port->ignore_status_mask |= UART_DUMMY_RSR_RX;
421 
422 	old_cr = readb(port->membase + UART010_CR) & ~UART010_CR_MSIE;
423 
424 	if (UART_ENABLE_MS(port, termios->c_cflag))
425 		old_cr |= UART010_CR_MSIE;
426 
427 	/* Set baud rate */
428 	quot -= 1;
429 	writel((quot & 0xf00) >> 8, port->membase + UART010_LCRM);
430 	writel(quot & 0xff, port->membase + UART010_LCRL);
431 
432 	/*
433 	 * ----------v----------v----------v----------v-----
434 	 * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
435 	 * ----------^----------^----------^----------^-----
436 	 */
437 	writel(lcr_h, port->membase + UART010_LCRH);
438 	writel(old_cr, port->membase + UART010_CR);
439 
440 	spin_unlock_irqrestore(&port->lock, flags);
441 }
442 
443 static void pl010_set_ldisc(struct uart_port *port, struct ktermios *termios)
444 {
445 	if (termios->c_line == N_PPS) {
446 		port->flags |= UPF_HARDPPS_CD;
447 		spin_lock_irq(&port->lock);
448 		pl010_enable_ms(port);
449 		spin_unlock_irq(&port->lock);
450 	} else {
451 		port->flags &= ~UPF_HARDPPS_CD;
452 		if (!UART_ENABLE_MS(port, termios->c_cflag)) {
453 			spin_lock_irq(&port->lock);
454 			pl010_disable_ms(port);
455 			spin_unlock_irq(&port->lock);
456 		}
457 	}
458 }
459 
460 static const char *pl010_type(struct uart_port *port)
461 {
462 	return port->type == PORT_AMBA ? "AMBA" : NULL;
463 }
464 
465 /*
466  * Release the memory region(s) being used by 'port'
467  */
468 static void pl010_release_port(struct uart_port *port)
469 {
470 	release_mem_region(port->mapbase, UART_PORT_SIZE);
471 }
472 
473 /*
474  * Request the memory region(s) being used by 'port'
475  */
476 static int pl010_request_port(struct uart_port *port)
477 {
478 	return request_mem_region(port->mapbase, UART_PORT_SIZE, "uart-pl010")
479 			!= NULL ? 0 : -EBUSY;
480 }
481 
482 /*
483  * Configure/autoconfigure the port.
484  */
485 static void pl010_config_port(struct uart_port *port, int flags)
486 {
487 	if (flags & UART_CONFIG_TYPE) {
488 		port->type = PORT_AMBA;
489 		pl010_request_port(port);
490 	}
491 }
492 
493 /*
494  * verify the new serial_struct (for TIOCSSERIAL).
495  */
496 static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser)
497 {
498 	int ret = 0;
499 	if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
500 		ret = -EINVAL;
501 	if (ser->irq < 0 || ser->irq >= nr_irqs)
502 		ret = -EINVAL;
503 	if (ser->baud_base < 9600)
504 		ret = -EINVAL;
505 	return ret;
506 }
507 
508 static const struct uart_ops amba_pl010_pops = {
509 	.tx_empty	= pl010_tx_empty,
510 	.set_mctrl	= pl010_set_mctrl,
511 	.get_mctrl	= pl010_get_mctrl,
512 	.stop_tx	= pl010_stop_tx,
513 	.start_tx	= pl010_start_tx,
514 	.stop_rx	= pl010_stop_rx,
515 	.enable_ms	= pl010_enable_ms,
516 	.break_ctl	= pl010_break_ctl,
517 	.startup	= pl010_startup,
518 	.shutdown	= pl010_shutdown,
519 	.set_termios	= pl010_set_termios,
520 	.set_ldisc	= pl010_set_ldisc,
521 	.type		= pl010_type,
522 	.release_port	= pl010_release_port,
523 	.request_port	= pl010_request_port,
524 	.config_port	= pl010_config_port,
525 	.verify_port	= pl010_verify_port,
526 };
527 
528 static struct uart_amba_port *amba_ports[UART_NR];
529 
530 #ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE
531 
532 static void pl010_console_putchar(struct uart_port *port, unsigned char ch)
533 {
534 	unsigned int status;
535 
536 	do {
537 		status = readb(port->membase + UART01x_FR);
538 		barrier();
539 	} while (!UART_TX_READY(status));
540 	writel(ch, port->membase + UART01x_DR);
541 }
542 
543 static void
544 pl010_console_write(struct console *co, const char *s, unsigned int count)
545 {
546 	struct uart_amba_port *uap = amba_ports[co->index];
547 	struct uart_port *port = &uap->port;
548 	unsigned int status, old_cr;
549 
550 	clk_enable(uap->clk);
551 
552 	/*
553 	 *	First save the CR then disable the interrupts
554 	 */
555 	old_cr = readb(port->membase + UART010_CR);
556 	writel(UART01x_CR_UARTEN, port->membase + UART010_CR);
557 
558 	uart_console_write(port, s, count, pl010_console_putchar);
559 
560 	/*
561 	 *	Finally, wait for transmitter to become empty
562 	 *	and restore the TCR
563 	 */
564 	do {
565 		status = readb(port->membase + UART01x_FR);
566 		barrier();
567 	} while (status & UART01x_FR_BUSY);
568 	writel(old_cr, port->membase + UART010_CR);
569 
570 	clk_disable(uap->clk);
571 }
572 
573 static void __init
574 pl010_console_get_options(struct uart_amba_port *uap, int *baud,
575 			     int *parity, int *bits)
576 {
577 	if (readb(uap->port.membase + UART010_CR) & UART01x_CR_UARTEN) {
578 		unsigned int lcr_h, quot;
579 		lcr_h = readb(uap->port.membase + UART010_LCRH);
580 
581 		*parity = 'n';
582 		if (lcr_h & UART01x_LCRH_PEN) {
583 			if (lcr_h & UART01x_LCRH_EPS)
584 				*parity = 'e';
585 			else
586 				*parity = 'o';
587 		}
588 
589 		if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
590 			*bits = 7;
591 		else
592 			*bits = 8;
593 
594 		quot = readb(uap->port.membase + UART010_LCRL) |
595 		       readb(uap->port.membase + UART010_LCRM) << 8;
596 		*baud = uap->port.uartclk / (16 * (quot + 1));
597 	}
598 }
599 
600 static int __init pl010_console_setup(struct console *co, char *options)
601 {
602 	struct uart_amba_port *uap;
603 	int baud = 38400;
604 	int bits = 8;
605 	int parity = 'n';
606 	int flow = 'n';
607 	int ret;
608 
609 	/*
610 	 * Check whether an invalid uart number has been specified, and
611 	 * if so, search for the first available port that does have
612 	 * console support.
613 	 */
614 	if (co->index >= UART_NR)
615 		co->index = 0;
616 	uap = amba_ports[co->index];
617 	if (!uap)
618 		return -ENODEV;
619 
620 	ret = clk_prepare(uap->clk);
621 	if (ret)
622 		return ret;
623 
624 	uap->port.uartclk = clk_get_rate(uap->clk);
625 
626 	if (options)
627 		uart_parse_options(options, &baud, &parity, &bits, &flow);
628 	else
629 		pl010_console_get_options(uap, &baud, &parity, &bits);
630 
631 	return uart_set_options(&uap->port, co, baud, parity, bits, flow);
632 }
633 
634 static struct uart_driver amba_reg;
635 static struct console amba_console = {
636 	.name		= "ttyAM",
637 	.write		= pl010_console_write,
638 	.device		= uart_console_device,
639 	.setup		= pl010_console_setup,
640 	.flags		= CON_PRINTBUFFER,
641 	.index		= -1,
642 	.data		= &amba_reg,
643 };
644 
645 #define AMBA_CONSOLE	&amba_console
646 #else
647 #define AMBA_CONSOLE	NULL
648 #endif
649 
650 static DEFINE_MUTEX(amba_reg_lock);
651 static struct uart_driver amba_reg = {
652 	.owner			= THIS_MODULE,
653 	.driver_name		= "ttyAM",
654 	.dev_name		= "ttyAM",
655 	.major			= SERIAL_AMBA_MAJOR,
656 	.minor			= SERIAL_AMBA_MINOR,
657 	.nr			= UART_NR,
658 	.cons			= AMBA_CONSOLE,
659 };
660 
661 static int pl010_probe(struct amba_device *dev, const struct amba_id *id)
662 {
663 	struct uart_amba_port *uap;
664 	void __iomem *base;
665 	int i, ret;
666 
667 	for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
668 		if (amba_ports[i] == NULL)
669 			break;
670 
671 	if (i == ARRAY_SIZE(amba_ports))
672 		return -EBUSY;
673 
674 	uap = devm_kzalloc(&dev->dev, sizeof(struct uart_amba_port),
675 			   GFP_KERNEL);
676 	if (!uap)
677 		return -ENOMEM;
678 
679 	base = devm_ioremap(&dev->dev, dev->res.start,
680 			    resource_size(&dev->res));
681 	if (!base)
682 		return -ENOMEM;
683 
684 	uap->clk = devm_clk_get(&dev->dev, NULL);
685 	if (IS_ERR(uap->clk))
686 		return PTR_ERR(uap->clk);
687 
688 	uap->port.dev = &dev->dev;
689 	uap->port.mapbase = dev->res.start;
690 	uap->port.membase = base;
691 	uap->port.iotype = UPIO_MEM;
692 	uap->port.irq = dev->irq[0];
693 	uap->port.fifosize = 16;
694 	uap->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_AMBA_PL010_CONSOLE);
695 	uap->port.ops = &amba_pl010_pops;
696 	uap->port.flags = UPF_BOOT_AUTOCONF;
697 	uap->port.line = i;
698 	uap->dev = dev;
699 	uap->data = dev_get_platdata(&dev->dev);
700 
701 	amba_ports[i] = uap;
702 
703 	amba_set_drvdata(dev, uap);
704 
705 	mutex_lock(&amba_reg_lock);
706 	if (!amba_reg.state) {
707 		ret = uart_register_driver(&amba_reg);
708 		if (ret < 0) {
709 			mutex_unlock(&amba_reg_lock);
710 			dev_err(uap->port.dev,
711 				"Failed to register AMBA-PL010 driver\n");
712 			return ret;
713 		}
714 	}
715 	mutex_unlock(&amba_reg_lock);
716 
717 	ret = uart_add_one_port(&amba_reg, &uap->port);
718 	if (ret)
719 		amba_ports[i] = NULL;
720 
721 	return ret;
722 }
723 
724 static void pl010_remove(struct amba_device *dev)
725 {
726 	struct uart_amba_port *uap = amba_get_drvdata(dev);
727 	int i;
728 	bool busy = false;
729 
730 	uart_remove_one_port(&amba_reg, &uap->port);
731 
732 	for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
733 		if (amba_ports[i] == uap)
734 			amba_ports[i] = NULL;
735 		else if (amba_ports[i])
736 			busy = true;
737 
738 	if (!busy)
739 		uart_unregister_driver(&amba_reg);
740 }
741 
742 #ifdef CONFIG_PM_SLEEP
743 static int pl010_suspend(struct device *dev)
744 {
745 	struct uart_amba_port *uap = dev_get_drvdata(dev);
746 
747 	if (uap)
748 		uart_suspend_port(&amba_reg, &uap->port);
749 
750 	return 0;
751 }
752 
753 static int pl010_resume(struct device *dev)
754 {
755 	struct uart_amba_port *uap = dev_get_drvdata(dev);
756 
757 	if (uap)
758 		uart_resume_port(&amba_reg, &uap->port);
759 
760 	return 0;
761 }
762 #endif
763 
764 static SIMPLE_DEV_PM_OPS(pl010_dev_pm_ops, pl010_suspend, pl010_resume);
765 
766 static const struct amba_id pl010_ids[] = {
767 	{
768 		.id	= 0x00041010,
769 		.mask	= 0x000fffff,
770 	},
771 	{ 0, 0 },
772 };
773 
774 MODULE_DEVICE_TABLE(amba, pl010_ids);
775 
776 static struct amba_driver pl010_driver = {
777 	.drv = {
778 		.name	= "uart-pl010",
779 		.pm	= &pl010_dev_pm_ops,
780 	},
781 	.id_table	= pl010_ids,
782 	.probe		= pl010_probe,
783 	.remove		= pl010_remove,
784 };
785 
786 static int __init pl010_init(void)
787 {
788 	printk(KERN_INFO "Serial: AMBA driver\n");
789 
790 	return  amba_driver_register(&pl010_driver);
791 }
792 
793 static void __exit pl010_exit(void)
794 {
795 	amba_driver_unregister(&pl010_driver);
796 }
797 
798 module_init(pl010_init);
799 module_exit(pl010_exit);
800 
801 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
802 MODULE_DESCRIPTION("ARM AMBA serial port driver");
803 MODULE_LICENSE("GPL");
804