xref: /openbmc/linux/drivers/tty/serial/amba-pl010.c (revision 0e17c50f)
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_amba_port *uap)
114 {
115 	unsigned int status, ch, flag, rsr, max_count = 256;
116 
117 	status = readb(uap->port.membase + UART01x_FR);
118 	while (UART_RX_DATA(status) && max_count--) {
119 		ch = readb(uap->port.membase + UART01x_DR);
120 		flag = TTY_NORMAL;
121 
122 		uap->port.icount.rx++;
123 
124 		/*
125 		 * Note that the error handling code is
126 		 * out of the main execution path
127 		 */
128 		rsr = readb(uap->port.membase + UART01x_RSR) | UART_DUMMY_RSR_RX;
129 		if (unlikely(rsr & UART01x_RSR_ANY)) {
130 			writel(0, uap->port.membase + UART01x_ECR);
131 
132 			if (rsr & UART01x_RSR_BE) {
133 				rsr &= ~(UART01x_RSR_FE | UART01x_RSR_PE);
134 				uap->port.icount.brk++;
135 				if (uart_handle_break(&uap->port))
136 					goto ignore_char;
137 			} else if (rsr & UART01x_RSR_PE)
138 				uap->port.icount.parity++;
139 			else if (rsr & UART01x_RSR_FE)
140 				uap->port.icount.frame++;
141 			if (rsr & UART01x_RSR_OE)
142 				uap->port.icount.overrun++;
143 
144 			rsr &= uap->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(&uap->port, ch))
155 			goto ignore_char;
156 
157 		uart_insert_char(&uap->port, rsr, UART01x_RSR_OE, ch, flag);
158 
159 	ignore_char:
160 		status = readb(uap->port.membase + UART01x_FR);
161 	}
162 	spin_unlock(&uap->port.lock);
163 	tty_flip_buffer_push(&uap->port.state->port);
164 	spin_lock(&uap->port.lock);
165 }
166 
167 static void pl010_tx_chars(struct uart_amba_port *uap)
168 {
169 	struct circ_buf *xmit = &uap->port.state->xmit;
170 	int count;
171 
172 	if (uap->port.x_char) {
173 		writel(uap->port.x_char, uap->port.membase + UART01x_DR);
174 		uap->port.icount.tx++;
175 		uap->port.x_char = 0;
176 		return;
177 	}
178 	if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) {
179 		pl010_stop_tx(&uap->port);
180 		return;
181 	}
182 
183 	count = uap->port.fifosize >> 1;
184 	do {
185 		writel(xmit->buf[xmit->tail], uap->port.membase + UART01x_DR);
186 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
187 		uap->port.icount.tx++;
188 		if (uart_circ_empty(xmit))
189 			break;
190 	} while (--count > 0);
191 
192 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
193 		uart_write_wakeup(&uap->port);
194 
195 	if (uart_circ_empty(xmit))
196 		pl010_stop_tx(&uap->port);
197 }
198 
199 static void pl010_modem_status(struct uart_amba_port *uap)
200 {
201 	unsigned int status, delta;
202 
203 	writel(0, uap->port.membase + UART010_ICR);
204 
205 	status = readb(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
206 
207 	delta = status ^ uap->old_status;
208 	uap->old_status = status;
209 
210 	if (!delta)
211 		return;
212 
213 	if (delta & UART01x_FR_DCD)
214 		uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD);
215 
216 	if (delta & UART01x_FR_DSR)
217 		uap->port.icount.dsr++;
218 
219 	if (delta & UART01x_FR_CTS)
220 		uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS);
221 
222 	wake_up_interruptible(&uap->port.state->port.delta_msr_wait);
223 }
224 
225 static irqreturn_t pl010_int(int irq, void *dev_id)
226 {
227 	struct uart_amba_port *uap = dev_id;
228 	unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
229 	int handled = 0;
230 
231 	spin_lock(&uap->port.lock);
232 
233 	status = readb(uap->port.membase + UART010_IIR);
234 	if (status) {
235 		do {
236 			if (status & (UART010_IIR_RTIS | UART010_IIR_RIS))
237 				pl010_rx_chars(uap);
238 			if (status & UART010_IIR_MIS)
239 				pl010_modem_status(uap);
240 			if (status & UART010_IIR_TIS)
241 				pl010_tx_chars(uap);
242 
243 			if (pass_counter-- == 0)
244 				break;
245 
246 			status = readb(uap->port.membase + UART010_IIR);
247 		} while (status & (UART010_IIR_RTIS | UART010_IIR_RIS |
248 				   UART010_IIR_TIS));
249 		handled = 1;
250 	}
251 
252 	spin_unlock(&uap->port.lock);
253 
254 	return IRQ_RETVAL(handled);
255 }
256 
257 static unsigned int pl010_tx_empty(struct uart_port *port)
258 {
259 	struct uart_amba_port *uap =
260 		container_of(port, struct uart_amba_port, port);
261 	unsigned int status = readb(uap->port.membase + UART01x_FR);
262 	return status & UART01x_FR_BUSY ? 0 : TIOCSER_TEMT;
263 }
264 
265 static unsigned int pl010_get_mctrl(struct uart_port *port)
266 {
267 	struct uart_amba_port *uap =
268 		container_of(port, struct uart_amba_port, port);
269 	unsigned int result = 0;
270 	unsigned int status;
271 
272 	status = readb(uap->port.membase + UART01x_FR);
273 	if (status & UART01x_FR_DCD)
274 		result |= TIOCM_CAR;
275 	if (status & UART01x_FR_DSR)
276 		result |= TIOCM_DSR;
277 	if (status & UART01x_FR_CTS)
278 		result |= TIOCM_CTS;
279 
280 	return result;
281 }
282 
283 static void pl010_set_mctrl(struct uart_port *port, unsigned int mctrl)
284 {
285 	struct uart_amba_port *uap =
286 		container_of(port, struct uart_amba_port, port);
287 
288 	if (uap->data)
289 		uap->data->set_mctrl(uap->dev, uap->port.membase, mctrl);
290 }
291 
292 static void pl010_break_ctl(struct uart_port *port, int break_state)
293 {
294 	struct uart_amba_port *uap =
295 		container_of(port, struct uart_amba_port, port);
296 	unsigned long flags;
297 	unsigned int lcr_h;
298 
299 	spin_lock_irqsave(&uap->port.lock, flags);
300 	lcr_h = readb(uap->port.membase + UART010_LCRH);
301 	if (break_state == -1)
302 		lcr_h |= UART01x_LCRH_BRK;
303 	else
304 		lcr_h &= ~UART01x_LCRH_BRK;
305 	writel(lcr_h, uap->port.membase + UART010_LCRH);
306 	spin_unlock_irqrestore(&uap->port.lock, flags);
307 }
308 
309 static int pl010_startup(struct uart_port *port)
310 {
311 	struct uart_amba_port *uap =
312 		container_of(port, struct uart_amba_port, port);
313 	int retval;
314 
315 	/*
316 	 * Try to enable the clock producer.
317 	 */
318 	retval = clk_prepare_enable(uap->clk);
319 	if (retval)
320 		goto out;
321 
322 	uap->port.uartclk = clk_get_rate(uap->clk);
323 
324 	/*
325 	 * Allocate the IRQ
326 	 */
327 	retval = request_irq(uap->port.irq, pl010_int, 0, "uart-pl010", uap);
328 	if (retval)
329 		goto clk_dis;
330 
331 	/*
332 	 * initialise the old status of the modem signals
333 	 */
334 	uap->old_status = readb(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
335 
336 	/*
337 	 * Finally, enable interrupts
338 	 */
339 	writel(UART01x_CR_UARTEN | UART010_CR_RIE | UART010_CR_RTIE,
340 	       uap->port.membase + UART010_CR);
341 
342 	return 0;
343 
344  clk_dis:
345 	clk_disable_unprepare(uap->clk);
346  out:
347 	return retval;
348 }
349 
350 static void pl010_shutdown(struct uart_port *port)
351 {
352 	struct uart_amba_port *uap =
353 		container_of(port, struct uart_amba_port, port);
354 
355 	/*
356 	 * Free the interrupt
357 	 */
358 	free_irq(uap->port.irq, uap);
359 
360 	/*
361 	 * disable all interrupts, disable the port
362 	 */
363 	writel(0, uap->port.membase + UART010_CR);
364 
365 	/* disable break condition and fifos */
366 	writel(readb(uap->port.membase + UART010_LCRH) &
367 		~(UART01x_LCRH_BRK | UART01x_LCRH_FEN),
368 	       uap->port.membase + UART010_LCRH);
369 
370 	/*
371 	 * Shut down the clock producer
372 	 */
373 	clk_disable_unprepare(uap->clk);
374 }
375 
376 static void
377 pl010_set_termios(struct uart_port *port, struct ktermios *termios,
378 		     struct ktermios *old)
379 {
380 	struct uart_amba_port *uap =
381 		container_of(port, 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 & (IGNBRK | 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, struct ktermios *termios)
476 {
477 	if (termios->c_line == N_PPS) {
478 		port->flags |= UPF_HARDPPS_CD;
479 		spin_lock_irq(&port->lock);
480 		pl010_enable_ms(port);
481 		spin_unlock_irq(&port->lock);
482 	} else {
483 		port->flags &= ~UPF_HARDPPS_CD;
484 		if (!UART_ENABLE_MS(port, termios->c_cflag)) {
485 			spin_lock_irq(&port->lock);
486 			pl010_disable_ms(port);
487 			spin_unlock_irq(&port->lock);
488 		}
489 	}
490 }
491 
492 static const char *pl010_type(struct uart_port *port)
493 {
494 	return port->type == PORT_AMBA ? "AMBA" : NULL;
495 }
496 
497 /*
498  * Release the memory region(s) being used by 'port'
499  */
500 static void pl010_release_port(struct uart_port *port)
501 {
502 	release_mem_region(port->mapbase, UART_PORT_SIZE);
503 }
504 
505 /*
506  * Request the memory region(s) being used by 'port'
507  */
508 static int pl010_request_port(struct uart_port *port)
509 {
510 	return request_mem_region(port->mapbase, UART_PORT_SIZE, "uart-pl010")
511 			!= NULL ? 0 : -EBUSY;
512 }
513 
514 /*
515  * Configure/autoconfigure the port.
516  */
517 static void pl010_config_port(struct uart_port *port, int flags)
518 {
519 	if (flags & UART_CONFIG_TYPE) {
520 		port->type = PORT_AMBA;
521 		pl010_request_port(port);
522 	}
523 }
524 
525 /*
526  * verify the new serial_struct (for TIOCSSERIAL).
527  */
528 static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser)
529 {
530 	int ret = 0;
531 	if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
532 		ret = -EINVAL;
533 	if (ser->irq < 0 || ser->irq >= nr_irqs)
534 		ret = -EINVAL;
535 	if (ser->baud_base < 9600)
536 		ret = -EINVAL;
537 	return ret;
538 }
539 
540 static const struct uart_ops amba_pl010_pops = {
541 	.tx_empty	= pl010_tx_empty,
542 	.set_mctrl	= pl010_set_mctrl,
543 	.get_mctrl	= pl010_get_mctrl,
544 	.stop_tx	= pl010_stop_tx,
545 	.start_tx	= pl010_start_tx,
546 	.stop_rx	= pl010_stop_rx,
547 	.enable_ms	= pl010_enable_ms,
548 	.break_ctl	= pl010_break_ctl,
549 	.startup	= pl010_startup,
550 	.shutdown	= pl010_shutdown,
551 	.set_termios	= pl010_set_termios,
552 	.set_ldisc	= pl010_set_ldisc,
553 	.type		= pl010_type,
554 	.release_port	= pl010_release_port,
555 	.request_port	= pl010_request_port,
556 	.config_port	= pl010_config_port,
557 	.verify_port	= pl010_verify_port,
558 };
559 
560 static struct uart_amba_port *amba_ports[UART_NR];
561 
562 #ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE
563 
564 static void pl010_console_putchar(struct uart_port *port, int ch)
565 {
566 	struct uart_amba_port *uap =
567 		container_of(port, struct uart_amba_port, port);
568 	unsigned int status;
569 
570 	do {
571 		status = readb(uap->port.membase + UART01x_FR);
572 		barrier();
573 	} while (!UART_TX_READY(status));
574 	writel(ch, uap->port.membase + UART01x_DR);
575 }
576 
577 static void
578 pl010_console_write(struct console *co, const char *s, unsigned int count)
579 {
580 	struct uart_amba_port *uap = amba_ports[co->index];
581 	unsigned int status, old_cr;
582 
583 	clk_enable(uap->clk);
584 
585 	/*
586 	 *	First save the CR then disable the interrupts
587 	 */
588 	old_cr = readb(uap->port.membase + UART010_CR);
589 	writel(UART01x_CR_UARTEN, uap->port.membase + UART010_CR);
590 
591 	uart_console_write(&uap->port, s, count, pl010_console_putchar);
592 
593 	/*
594 	 *	Finally, wait for transmitter to become empty
595 	 *	and restore the TCR
596 	 */
597 	do {
598 		status = readb(uap->port.membase + UART01x_FR);
599 		barrier();
600 	} while (status & UART01x_FR_BUSY);
601 	writel(old_cr, uap->port.membase + UART010_CR);
602 
603 	clk_disable(uap->clk);
604 }
605 
606 static void __init
607 pl010_console_get_options(struct uart_amba_port *uap, int *baud,
608 			     int *parity, int *bits)
609 {
610 	if (readb(uap->port.membase + UART010_CR) & UART01x_CR_UARTEN) {
611 		unsigned int lcr_h, quot;
612 		lcr_h = readb(uap->port.membase + UART010_LCRH);
613 
614 		*parity = 'n';
615 		if (lcr_h & UART01x_LCRH_PEN) {
616 			if (lcr_h & UART01x_LCRH_EPS)
617 				*parity = 'e';
618 			else
619 				*parity = 'o';
620 		}
621 
622 		if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
623 			*bits = 7;
624 		else
625 			*bits = 8;
626 
627 		quot = readb(uap->port.membase + UART010_LCRL) |
628 		       readb(uap->port.membase + UART010_LCRM) << 8;
629 		*baud = uap->port.uartclk / (16 * (quot + 1));
630 	}
631 }
632 
633 static int __init pl010_console_setup(struct console *co, char *options)
634 {
635 	struct uart_amba_port *uap;
636 	int baud = 38400;
637 	int bits = 8;
638 	int parity = 'n';
639 	int flow = 'n';
640 	int ret;
641 
642 	/*
643 	 * Check whether an invalid uart number has been specified, and
644 	 * if so, search for the first available port that does have
645 	 * console support.
646 	 */
647 	if (co->index >= UART_NR)
648 		co->index = 0;
649 	uap = amba_ports[co->index];
650 	if (!uap)
651 		return -ENODEV;
652 
653 	ret = clk_prepare(uap->clk);
654 	if (ret)
655 		return ret;
656 
657 	uap->port.uartclk = clk_get_rate(uap->clk);
658 
659 	if (options)
660 		uart_parse_options(options, &baud, &parity, &bits, &flow);
661 	else
662 		pl010_console_get_options(uap, &baud, &parity, &bits);
663 
664 	return uart_set_options(&uap->port, co, baud, parity, bits, flow);
665 }
666 
667 static struct uart_driver amba_reg;
668 static struct console amba_console = {
669 	.name		= "ttyAM",
670 	.write		= pl010_console_write,
671 	.device		= uart_console_device,
672 	.setup		= pl010_console_setup,
673 	.flags		= CON_PRINTBUFFER,
674 	.index		= -1,
675 	.data		= &amba_reg,
676 };
677 
678 #define AMBA_CONSOLE	&amba_console
679 #else
680 #define AMBA_CONSOLE	NULL
681 #endif
682 
683 static DEFINE_MUTEX(amba_reg_lock);
684 static struct uart_driver amba_reg = {
685 	.owner			= THIS_MODULE,
686 	.driver_name		= "ttyAM",
687 	.dev_name		= "ttyAM",
688 	.major			= SERIAL_AMBA_MAJOR,
689 	.minor			= SERIAL_AMBA_MINOR,
690 	.nr			= UART_NR,
691 	.cons			= AMBA_CONSOLE,
692 };
693 
694 static int pl010_probe(struct amba_device *dev, const struct amba_id *id)
695 {
696 	struct uart_amba_port *uap;
697 	void __iomem *base;
698 	int i, ret;
699 
700 	for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
701 		if (amba_ports[i] == NULL)
702 			break;
703 
704 	if (i == ARRAY_SIZE(amba_ports))
705 		return -EBUSY;
706 
707 	uap = devm_kzalloc(&dev->dev, sizeof(struct uart_amba_port),
708 			   GFP_KERNEL);
709 	if (!uap)
710 		return -ENOMEM;
711 
712 	base = devm_ioremap(&dev->dev, dev->res.start,
713 			    resource_size(&dev->res));
714 	if (!base)
715 		return -ENOMEM;
716 
717 	uap->clk = devm_clk_get(&dev->dev, NULL);
718 	if (IS_ERR(uap->clk))
719 		return PTR_ERR(uap->clk);
720 
721 	uap->port.dev = &dev->dev;
722 	uap->port.mapbase = dev->res.start;
723 	uap->port.membase = base;
724 	uap->port.iotype = UPIO_MEM;
725 	uap->port.irq = dev->irq[0];
726 	uap->port.fifosize = 16;
727 	uap->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_AMBA_PL010_CONSOLE);
728 	uap->port.ops = &amba_pl010_pops;
729 	uap->port.flags = UPF_BOOT_AUTOCONF;
730 	uap->port.line = i;
731 	uap->dev = dev;
732 	uap->data = dev_get_platdata(&dev->dev);
733 
734 	amba_ports[i] = uap;
735 
736 	amba_set_drvdata(dev, uap);
737 
738 	mutex_lock(&amba_reg_lock);
739 	if (!amba_reg.state) {
740 		ret = uart_register_driver(&amba_reg);
741 		if (ret < 0) {
742 			mutex_unlock(&amba_reg_lock);
743 			dev_err(uap->port.dev,
744 				"Failed to register AMBA-PL010 driver\n");
745 			return ret;
746 		}
747 	}
748 	mutex_unlock(&amba_reg_lock);
749 
750 	ret = uart_add_one_port(&amba_reg, &uap->port);
751 	if (ret)
752 		amba_ports[i] = NULL;
753 
754 	return ret;
755 }
756 
757 static int pl010_remove(struct amba_device *dev)
758 {
759 	struct uart_amba_port *uap = amba_get_drvdata(dev);
760 	int i;
761 	bool busy = false;
762 
763 	uart_remove_one_port(&amba_reg, &uap->port);
764 
765 	for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
766 		if (amba_ports[i] == uap)
767 			amba_ports[i] = NULL;
768 		else if (amba_ports[i])
769 			busy = true;
770 
771 	if (!busy)
772 		uart_unregister_driver(&amba_reg);
773 
774 	return 0;
775 }
776 
777 #ifdef CONFIG_PM_SLEEP
778 static int pl010_suspend(struct device *dev)
779 {
780 	struct uart_amba_port *uap = dev_get_drvdata(dev);
781 
782 	if (uap)
783 		uart_suspend_port(&amba_reg, &uap->port);
784 
785 	return 0;
786 }
787 
788 static int pl010_resume(struct device *dev)
789 {
790 	struct uart_amba_port *uap = dev_get_drvdata(dev);
791 
792 	if (uap)
793 		uart_resume_port(&amba_reg, &uap->port);
794 
795 	return 0;
796 }
797 #endif
798 
799 static SIMPLE_DEV_PM_OPS(pl010_dev_pm_ops, pl010_suspend, pl010_resume);
800 
801 static const struct amba_id pl010_ids[] = {
802 	{
803 		.id	= 0x00041010,
804 		.mask	= 0x000fffff,
805 	},
806 	{ 0, 0 },
807 };
808 
809 MODULE_DEVICE_TABLE(amba, pl010_ids);
810 
811 static struct amba_driver pl010_driver = {
812 	.drv = {
813 		.name	= "uart-pl010",
814 		.pm	= &pl010_dev_pm_ops,
815 	},
816 	.id_table	= pl010_ids,
817 	.probe		= pl010_probe,
818 	.remove		= pl010_remove,
819 };
820 
821 static int __init pl010_init(void)
822 {
823 	printk(KERN_INFO "Serial: AMBA driver\n");
824 
825 	return  amba_driver_register(&pl010_driver);
826 }
827 
828 static void __exit pl010_exit(void)
829 {
830 	amba_driver_unregister(&pl010_driver);
831 }
832 
833 module_init(pl010_init);
834 module_exit(pl010_exit);
835 
836 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
837 MODULE_DESCRIPTION("ARM AMBA serial port driver");
838 MODULE_LICENSE("GPL");
839