xref: /openbmc/linux/drivers/tty/serial/pxa.c (revision a06c488d)
1 /*
2  *  Based on drivers/serial/8250.c by Russell King.
3  *
4  *  Author:	Nicolas Pitre
5  *  Created:	Feb 20, 2003
6  *  Copyright:	(C) 2003 Monta Vista Software, Inc.
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * Note 1: This driver is made separate from the already too overloaded
14  * 8250.c because it needs some kirks of its own and that'll make it
15  * easier to add DMA support.
16  *
17  * Note 2: I'm too sick of device allocation policies for serial ports.
18  * If someone else wants to request an "official" allocation of major/minor
19  * for this driver please be my guest.  And don't forget that new hardware
20  * to come from Intel might have more than 3 or 4 of those UARTs.  Let's
21  * hope for a better port registration and dynamic device allocation scheme
22  * with the serial core maintainer satisfaction to appear soon.
23  */
24 
25 
26 #if defined(CONFIG_SERIAL_PXA_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
27 #define SUPPORT_SYSRQ
28 #endif
29 
30 #include <linux/module.h>
31 #include <linux/ioport.h>
32 #include <linux/init.h>
33 #include <linux/console.h>
34 #include <linux/sysrq.h>
35 #include <linux/serial_reg.h>
36 #include <linux/circ_buf.h>
37 #include <linux/delay.h>
38 #include <linux/interrupt.h>
39 #include <linux/of.h>
40 #include <linux/platform_device.h>
41 #include <linux/tty.h>
42 #include <linux/tty_flip.h>
43 #include <linux/serial_core.h>
44 #include <linux/clk.h>
45 #include <linux/io.h>
46 #include <linux/slab.h>
47 
48 #define PXA_NAME_LEN		8
49 
50 struct uart_pxa_port {
51 	struct uart_port        port;
52 	unsigned char           ier;
53 	unsigned char           lcr;
54 	unsigned char           mcr;
55 	unsigned int            lsr_break_flag;
56 	struct clk		*clk;
57 	char			name[PXA_NAME_LEN];
58 };
59 
60 static inline unsigned int serial_in(struct uart_pxa_port *up, int offset)
61 {
62 	offset <<= 2;
63 	return readl(up->port.membase + offset);
64 }
65 
66 static inline void serial_out(struct uart_pxa_port *up, int offset, int value)
67 {
68 	offset <<= 2;
69 	writel(value, up->port.membase + offset);
70 }
71 
72 static void serial_pxa_enable_ms(struct uart_port *port)
73 {
74 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
75 
76 	up->ier |= UART_IER_MSI;
77 	serial_out(up, UART_IER, up->ier);
78 }
79 
80 static void serial_pxa_stop_tx(struct uart_port *port)
81 {
82 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
83 
84 	if (up->ier & UART_IER_THRI) {
85 		up->ier &= ~UART_IER_THRI;
86 		serial_out(up, UART_IER, up->ier);
87 	}
88 }
89 
90 static void serial_pxa_stop_rx(struct uart_port *port)
91 {
92 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
93 
94 	up->ier &= ~UART_IER_RLSI;
95 	up->port.read_status_mask &= ~UART_LSR_DR;
96 	serial_out(up, UART_IER, up->ier);
97 }
98 
99 static inline void receive_chars(struct uart_pxa_port *up, int *status)
100 {
101 	unsigned int ch, flag;
102 	int max_count = 256;
103 
104 	do {
105 		/* work around Errata #20 according to
106 		 * Intel(R) PXA27x Processor Family
107 		 * Specification Update (May 2005)
108 		 *
109 		 * Step 2
110 		 * Disable the Reciever Time Out Interrupt via IER[RTOEI]
111 		 */
112 		up->ier &= ~UART_IER_RTOIE;
113 		serial_out(up, UART_IER, up->ier);
114 
115 		ch = serial_in(up, UART_RX);
116 		flag = TTY_NORMAL;
117 		up->port.icount.rx++;
118 
119 		if (unlikely(*status & (UART_LSR_BI | UART_LSR_PE |
120 				       UART_LSR_FE | UART_LSR_OE))) {
121 			/*
122 			 * For statistics only
123 			 */
124 			if (*status & UART_LSR_BI) {
125 				*status &= ~(UART_LSR_FE | UART_LSR_PE);
126 				up->port.icount.brk++;
127 				/*
128 				 * We do the SysRQ and SAK checking
129 				 * here because otherwise the break
130 				 * may get masked by ignore_status_mask
131 				 * or read_status_mask.
132 				 */
133 				if (uart_handle_break(&up->port))
134 					goto ignore_char;
135 			} else if (*status & UART_LSR_PE)
136 				up->port.icount.parity++;
137 			else if (*status & UART_LSR_FE)
138 				up->port.icount.frame++;
139 			if (*status & UART_LSR_OE)
140 				up->port.icount.overrun++;
141 
142 			/*
143 			 * Mask off conditions which should be ignored.
144 			 */
145 			*status &= up->port.read_status_mask;
146 
147 #ifdef CONFIG_SERIAL_PXA_CONSOLE
148 			if (up->port.line == up->port.cons->index) {
149 				/* Recover the break flag from console xmit */
150 				*status |= up->lsr_break_flag;
151 				up->lsr_break_flag = 0;
152 			}
153 #endif
154 			if (*status & UART_LSR_BI) {
155 				flag = TTY_BREAK;
156 			} else if (*status & UART_LSR_PE)
157 				flag = TTY_PARITY;
158 			else if (*status & UART_LSR_FE)
159 				flag = TTY_FRAME;
160 		}
161 
162 		if (uart_handle_sysrq_char(&up->port, ch))
163 			goto ignore_char;
164 
165 		uart_insert_char(&up->port, *status, UART_LSR_OE, ch, flag);
166 
167 	ignore_char:
168 		*status = serial_in(up, UART_LSR);
169 	} while ((*status & UART_LSR_DR) && (max_count-- > 0));
170 	tty_flip_buffer_push(&up->port.state->port);
171 
172 	/* work around Errata #20 according to
173 	 * Intel(R) PXA27x Processor Family
174 	 * Specification Update (May 2005)
175 	 *
176 	 * Step 6:
177 	 * No more data in FIFO: Re-enable RTO interrupt via IER[RTOIE]
178 	 */
179 	up->ier |= UART_IER_RTOIE;
180 	serial_out(up, UART_IER, up->ier);
181 }
182 
183 static void transmit_chars(struct uart_pxa_port *up)
184 {
185 	struct circ_buf *xmit = &up->port.state->xmit;
186 	int count;
187 
188 	if (up->port.x_char) {
189 		serial_out(up, UART_TX, up->port.x_char);
190 		up->port.icount.tx++;
191 		up->port.x_char = 0;
192 		return;
193 	}
194 	if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) {
195 		serial_pxa_stop_tx(&up->port);
196 		return;
197 	}
198 
199 	count = up->port.fifosize / 2;
200 	do {
201 		serial_out(up, UART_TX, xmit->buf[xmit->tail]);
202 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
203 		up->port.icount.tx++;
204 		if (uart_circ_empty(xmit))
205 			break;
206 	} while (--count > 0);
207 
208 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
209 		uart_write_wakeup(&up->port);
210 
211 
212 	if (uart_circ_empty(xmit))
213 		serial_pxa_stop_tx(&up->port);
214 }
215 
216 static void serial_pxa_start_tx(struct uart_port *port)
217 {
218 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
219 
220 	if (!(up->ier & UART_IER_THRI)) {
221 		up->ier |= UART_IER_THRI;
222 		serial_out(up, UART_IER, up->ier);
223 	}
224 }
225 
226 /* should hold up->port.lock */
227 static inline void check_modem_status(struct uart_pxa_port *up)
228 {
229 	int status;
230 
231 	status = serial_in(up, UART_MSR);
232 
233 	if ((status & UART_MSR_ANY_DELTA) == 0)
234 		return;
235 
236 	if (status & UART_MSR_TERI)
237 		up->port.icount.rng++;
238 	if (status & UART_MSR_DDSR)
239 		up->port.icount.dsr++;
240 	if (status & UART_MSR_DDCD)
241 		uart_handle_dcd_change(&up->port, status & UART_MSR_DCD);
242 	if (status & UART_MSR_DCTS)
243 		uart_handle_cts_change(&up->port, status & UART_MSR_CTS);
244 
245 	wake_up_interruptible(&up->port.state->port.delta_msr_wait);
246 }
247 
248 /*
249  * This handles the interrupt from one port.
250  */
251 static inline irqreturn_t serial_pxa_irq(int irq, void *dev_id)
252 {
253 	struct uart_pxa_port *up = dev_id;
254 	unsigned int iir, lsr;
255 
256 	iir = serial_in(up, UART_IIR);
257 	if (iir & UART_IIR_NO_INT)
258 		return IRQ_NONE;
259 	spin_lock(&up->port.lock);
260 	lsr = serial_in(up, UART_LSR);
261 	if (lsr & UART_LSR_DR)
262 		receive_chars(up, &lsr);
263 	check_modem_status(up);
264 	if (lsr & UART_LSR_THRE)
265 		transmit_chars(up);
266 	spin_unlock(&up->port.lock);
267 	return IRQ_HANDLED;
268 }
269 
270 static unsigned int serial_pxa_tx_empty(struct uart_port *port)
271 {
272 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
273 	unsigned long flags;
274 	unsigned int ret;
275 
276 	spin_lock_irqsave(&up->port.lock, flags);
277 	ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
278 	spin_unlock_irqrestore(&up->port.lock, flags);
279 
280 	return ret;
281 }
282 
283 static unsigned int serial_pxa_get_mctrl(struct uart_port *port)
284 {
285 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
286 	unsigned char status;
287 	unsigned int ret;
288 
289 	status = serial_in(up, UART_MSR);
290 
291 	ret = 0;
292 	if (status & UART_MSR_DCD)
293 		ret |= TIOCM_CAR;
294 	if (status & UART_MSR_RI)
295 		ret |= TIOCM_RNG;
296 	if (status & UART_MSR_DSR)
297 		ret |= TIOCM_DSR;
298 	if (status & UART_MSR_CTS)
299 		ret |= TIOCM_CTS;
300 	return ret;
301 }
302 
303 static void serial_pxa_set_mctrl(struct uart_port *port, unsigned int mctrl)
304 {
305 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
306 	unsigned char mcr = 0;
307 
308 	if (mctrl & TIOCM_RTS)
309 		mcr |= UART_MCR_RTS;
310 	if (mctrl & TIOCM_DTR)
311 		mcr |= UART_MCR_DTR;
312 	if (mctrl & TIOCM_OUT1)
313 		mcr |= UART_MCR_OUT1;
314 	if (mctrl & TIOCM_OUT2)
315 		mcr |= UART_MCR_OUT2;
316 	if (mctrl & TIOCM_LOOP)
317 		mcr |= UART_MCR_LOOP;
318 
319 	mcr |= up->mcr;
320 
321 	serial_out(up, UART_MCR, mcr);
322 }
323 
324 static void serial_pxa_break_ctl(struct uart_port *port, int break_state)
325 {
326 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
327 	unsigned long flags;
328 
329 	spin_lock_irqsave(&up->port.lock, flags);
330 	if (break_state == -1)
331 		up->lcr |= UART_LCR_SBC;
332 	else
333 		up->lcr &= ~UART_LCR_SBC;
334 	serial_out(up, UART_LCR, up->lcr);
335 	spin_unlock_irqrestore(&up->port.lock, flags);
336 }
337 
338 static int serial_pxa_startup(struct uart_port *port)
339 {
340 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
341 	unsigned long flags;
342 	int retval;
343 
344 	if (port->line == 3) /* HWUART */
345 		up->mcr |= UART_MCR_AFE;
346 	else
347 		up->mcr = 0;
348 
349 	up->port.uartclk = clk_get_rate(up->clk);
350 
351 	/*
352 	 * Allocate the IRQ
353 	 */
354 	retval = request_irq(up->port.irq, serial_pxa_irq, 0, up->name, up);
355 	if (retval)
356 		return retval;
357 
358 	/*
359 	 * Clear the FIFO buffers and disable them.
360 	 * (they will be reenabled in set_termios())
361 	 */
362 	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
363 	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
364 			UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
365 	serial_out(up, UART_FCR, 0);
366 
367 	/*
368 	 * Clear the interrupt registers.
369 	 */
370 	(void) serial_in(up, UART_LSR);
371 	(void) serial_in(up, UART_RX);
372 	(void) serial_in(up, UART_IIR);
373 	(void) serial_in(up, UART_MSR);
374 
375 	/*
376 	 * Now, initialize the UART
377 	 */
378 	serial_out(up, UART_LCR, UART_LCR_WLEN8);
379 
380 	spin_lock_irqsave(&up->port.lock, flags);
381 	up->port.mctrl |= TIOCM_OUT2;
382 	serial_pxa_set_mctrl(&up->port, up->port.mctrl);
383 	spin_unlock_irqrestore(&up->port.lock, flags);
384 
385 	/*
386 	 * Finally, enable interrupts.  Note: Modem status interrupts
387 	 * are set via set_termios(), which will be occurring imminently
388 	 * anyway, so we don't enable them here.
389 	 */
390 	up->ier = UART_IER_RLSI | UART_IER_RDI | UART_IER_RTOIE | UART_IER_UUE;
391 	serial_out(up, UART_IER, up->ier);
392 
393 	/*
394 	 * And clear the interrupt registers again for luck.
395 	 */
396 	(void) serial_in(up, UART_LSR);
397 	(void) serial_in(up, UART_RX);
398 	(void) serial_in(up, UART_IIR);
399 	(void) serial_in(up, UART_MSR);
400 
401 	return 0;
402 }
403 
404 static void serial_pxa_shutdown(struct uart_port *port)
405 {
406 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
407 	unsigned long flags;
408 
409 	free_irq(up->port.irq, up);
410 
411 	/*
412 	 * Disable interrupts from this port
413 	 */
414 	up->ier = 0;
415 	serial_out(up, UART_IER, 0);
416 
417 	spin_lock_irqsave(&up->port.lock, flags);
418 	up->port.mctrl &= ~TIOCM_OUT2;
419 	serial_pxa_set_mctrl(&up->port, up->port.mctrl);
420 	spin_unlock_irqrestore(&up->port.lock, flags);
421 
422 	/*
423 	 * Disable break condition and FIFOs
424 	 */
425 	serial_out(up, UART_LCR, serial_in(up, UART_LCR) & ~UART_LCR_SBC);
426 	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
427 				  UART_FCR_CLEAR_RCVR |
428 				  UART_FCR_CLEAR_XMIT);
429 	serial_out(up, UART_FCR, 0);
430 }
431 
432 static void
433 serial_pxa_set_termios(struct uart_port *port, struct ktermios *termios,
434 		       struct ktermios *old)
435 {
436 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
437 	unsigned char cval, fcr = 0;
438 	unsigned long flags;
439 	unsigned int baud, quot;
440 	unsigned int dll;
441 
442 	switch (termios->c_cflag & CSIZE) {
443 	case CS5:
444 		cval = UART_LCR_WLEN5;
445 		break;
446 	case CS6:
447 		cval = UART_LCR_WLEN6;
448 		break;
449 	case CS7:
450 		cval = UART_LCR_WLEN7;
451 		break;
452 	default:
453 	case CS8:
454 		cval = UART_LCR_WLEN8;
455 		break;
456 	}
457 
458 	if (termios->c_cflag & CSTOPB)
459 		cval |= UART_LCR_STOP;
460 	if (termios->c_cflag & PARENB)
461 		cval |= UART_LCR_PARITY;
462 	if (!(termios->c_cflag & PARODD))
463 		cval |= UART_LCR_EPAR;
464 
465 	/*
466 	 * Ask the core to calculate the divisor for us.
467 	 */
468 	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
469 	quot = uart_get_divisor(port, baud);
470 
471 	if ((up->port.uartclk / quot) < (2400 * 16))
472 		fcr = UART_FCR_ENABLE_FIFO | UART_FCR_PXAR1;
473 	else if ((up->port.uartclk / quot) < (230400 * 16))
474 		fcr = UART_FCR_ENABLE_FIFO | UART_FCR_PXAR8;
475 	else
476 		fcr = UART_FCR_ENABLE_FIFO | UART_FCR_PXAR32;
477 
478 	/*
479 	 * Ok, we're now changing the port state.  Do it with
480 	 * interrupts disabled.
481 	 */
482 	spin_lock_irqsave(&up->port.lock, flags);
483 
484 	/*
485 	 * Ensure the port will be enabled.
486 	 * This is required especially for serial console.
487 	 */
488 	up->ier |= UART_IER_UUE;
489 
490 	/*
491 	 * Update the per-port timeout.
492 	 */
493 	uart_update_timeout(port, termios->c_cflag, baud);
494 
495 	up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
496 	if (termios->c_iflag & INPCK)
497 		up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
498 	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
499 		up->port.read_status_mask |= UART_LSR_BI;
500 
501 	/*
502 	 * Characters to ignore
503 	 */
504 	up->port.ignore_status_mask = 0;
505 	if (termios->c_iflag & IGNPAR)
506 		up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
507 	if (termios->c_iflag & IGNBRK) {
508 		up->port.ignore_status_mask |= UART_LSR_BI;
509 		/*
510 		 * If we're ignoring parity and break indicators,
511 		 * ignore overruns too (for real raw support).
512 		 */
513 		if (termios->c_iflag & IGNPAR)
514 			up->port.ignore_status_mask |= UART_LSR_OE;
515 	}
516 
517 	/*
518 	 * ignore all characters if CREAD is not set
519 	 */
520 	if ((termios->c_cflag & CREAD) == 0)
521 		up->port.ignore_status_mask |= UART_LSR_DR;
522 
523 	/*
524 	 * CTS flow control flag and modem status interrupts
525 	 */
526 	up->ier &= ~UART_IER_MSI;
527 	if (UART_ENABLE_MS(&up->port, termios->c_cflag))
528 		up->ier |= UART_IER_MSI;
529 
530 	serial_out(up, UART_IER, up->ier);
531 
532 	if (termios->c_cflag & CRTSCTS)
533 		up->mcr |= UART_MCR_AFE;
534 	else
535 		up->mcr &= ~UART_MCR_AFE;
536 
537 	serial_out(up, UART_LCR, cval | UART_LCR_DLAB);	/* set DLAB */
538 	serial_out(up, UART_DLL, quot & 0xff);		/* LS of divisor */
539 
540 	/*
541 	 * work around Errata #75 according to Intel(R) PXA27x Processor Family
542 	 * Specification Update (Nov 2005)
543 	 */
544 	dll = serial_in(up, UART_DLL);
545 	WARN_ON(dll != (quot & 0xff));
546 
547 	serial_out(up, UART_DLM, quot >> 8);		/* MS of divisor */
548 	serial_out(up, UART_LCR, cval);			/* reset DLAB */
549 	up->lcr = cval;					/* Save LCR */
550 	serial_pxa_set_mctrl(&up->port, up->port.mctrl);
551 	serial_out(up, UART_FCR, fcr);
552 	spin_unlock_irqrestore(&up->port.lock, flags);
553 }
554 
555 static void
556 serial_pxa_pm(struct uart_port *port, unsigned int state,
557 	      unsigned int oldstate)
558 {
559 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
560 
561 	if (!state)
562 		clk_prepare_enable(up->clk);
563 	else
564 		clk_disable_unprepare(up->clk);
565 }
566 
567 static void serial_pxa_release_port(struct uart_port *port)
568 {
569 }
570 
571 static int serial_pxa_request_port(struct uart_port *port)
572 {
573 	return 0;
574 }
575 
576 static void serial_pxa_config_port(struct uart_port *port, int flags)
577 {
578 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
579 	up->port.type = PORT_PXA;
580 }
581 
582 static int
583 serial_pxa_verify_port(struct uart_port *port, struct serial_struct *ser)
584 {
585 	/* we don't want the core code to modify any port params */
586 	return -EINVAL;
587 }
588 
589 static const char *
590 serial_pxa_type(struct uart_port *port)
591 {
592 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
593 	return up->name;
594 }
595 
596 static struct uart_pxa_port *serial_pxa_ports[4];
597 static struct uart_driver serial_pxa_reg;
598 
599 #ifdef CONFIG_SERIAL_PXA_CONSOLE
600 
601 #define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
602 
603 /*
604  *	Wait for transmitter & holding register to empty
605  */
606 static void wait_for_xmitr(struct uart_pxa_port *up)
607 {
608 	unsigned int status, tmout = 10000;
609 
610 	/* Wait up to 10ms for the character(s) to be sent. */
611 	do {
612 		status = serial_in(up, UART_LSR);
613 
614 		if (status & UART_LSR_BI)
615 			up->lsr_break_flag = UART_LSR_BI;
616 
617 		if (--tmout == 0)
618 			break;
619 		udelay(1);
620 	} while ((status & BOTH_EMPTY) != BOTH_EMPTY);
621 
622 	/* Wait up to 1s for flow control if necessary */
623 	if (up->port.flags & UPF_CONS_FLOW) {
624 		tmout = 1000000;
625 		while (--tmout &&
626 		       ((serial_in(up, UART_MSR) & UART_MSR_CTS) == 0))
627 			udelay(1);
628 	}
629 }
630 
631 static void serial_pxa_console_putchar(struct uart_port *port, int ch)
632 {
633 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
634 
635 	wait_for_xmitr(up);
636 	serial_out(up, UART_TX, ch);
637 }
638 
639 /*
640  * Print a string to the serial port trying not to disturb
641  * any possible real use of the port...
642  *
643  *	The console_lock must be held when we get here.
644  */
645 static void
646 serial_pxa_console_write(struct console *co, const char *s, unsigned int count)
647 {
648 	struct uart_pxa_port *up = serial_pxa_ports[co->index];
649 	unsigned int ier;
650 	unsigned long flags;
651 	int locked = 1;
652 
653 	clk_enable(up->clk);
654 	local_irq_save(flags);
655 	if (up->port.sysrq)
656 		locked = 0;
657 	else if (oops_in_progress)
658 		locked = spin_trylock(&up->port.lock);
659 	else
660 		spin_lock(&up->port.lock);
661 
662 	/*
663 	 *	First save the IER then disable the interrupts
664 	 */
665 	ier = serial_in(up, UART_IER);
666 	serial_out(up, UART_IER, UART_IER_UUE);
667 
668 	uart_console_write(&up->port, s, count, serial_pxa_console_putchar);
669 
670 	/*
671 	 *	Finally, wait for transmitter to become empty
672 	 *	and restore the IER
673 	 */
674 	wait_for_xmitr(up);
675 	serial_out(up, UART_IER, ier);
676 
677 	if (locked)
678 		spin_unlock(&up->port.lock);
679 	local_irq_restore(flags);
680 	clk_disable(up->clk);
681 
682 }
683 
684 #ifdef CONFIG_CONSOLE_POLL
685 /*
686  * Console polling routines for writing and reading from the uart while
687  * in an interrupt or debug context.
688  */
689 
690 static int serial_pxa_get_poll_char(struct uart_port *port)
691 {
692 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
693 	unsigned char lsr = serial_in(up, UART_LSR);
694 
695 	while (!(lsr & UART_LSR_DR))
696 		lsr = serial_in(up, UART_LSR);
697 
698 	return serial_in(up, UART_RX);
699 }
700 
701 
702 static void serial_pxa_put_poll_char(struct uart_port *port,
703 			 unsigned char c)
704 {
705 	unsigned int ier;
706 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
707 
708 	/*
709 	 *	First save the IER then disable the interrupts
710 	 */
711 	ier = serial_in(up, UART_IER);
712 	serial_out(up, UART_IER, UART_IER_UUE);
713 
714 	wait_for_xmitr(up);
715 	/*
716 	 *	Send the character out.
717 	 */
718 	serial_out(up, UART_TX, c);
719 
720 	/*
721 	 *	Finally, wait for transmitter to become empty
722 	 *	and restore the IER
723 	 */
724 	wait_for_xmitr(up);
725 	serial_out(up, UART_IER, ier);
726 }
727 
728 #endif /* CONFIG_CONSOLE_POLL */
729 
730 static int __init
731 serial_pxa_console_setup(struct console *co, char *options)
732 {
733 	struct uart_pxa_port *up;
734 	int baud = 9600;
735 	int bits = 8;
736 	int parity = 'n';
737 	int flow = 'n';
738 
739 	if (co->index == -1 || co->index >= serial_pxa_reg.nr)
740 		co->index = 0;
741 	up = serial_pxa_ports[co->index];
742 	if (!up)
743 		return -ENODEV;
744 
745 	if (options)
746 		uart_parse_options(options, &baud, &parity, &bits, &flow);
747 
748 	return uart_set_options(&up->port, co, baud, parity, bits, flow);
749 }
750 
751 static struct console serial_pxa_console = {
752 	.name		= "ttyS",
753 	.write		= serial_pxa_console_write,
754 	.device		= uart_console_device,
755 	.setup		= serial_pxa_console_setup,
756 	.flags		= CON_PRINTBUFFER,
757 	.index		= -1,
758 	.data		= &serial_pxa_reg,
759 };
760 
761 #define PXA_CONSOLE	&serial_pxa_console
762 #else
763 #define PXA_CONSOLE	NULL
764 #endif
765 
766 static struct uart_ops serial_pxa_pops = {
767 	.tx_empty	= serial_pxa_tx_empty,
768 	.set_mctrl	= serial_pxa_set_mctrl,
769 	.get_mctrl	= serial_pxa_get_mctrl,
770 	.stop_tx	= serial_pxa_stop_tx,
771 	.start_tx	= serial_pxa_start_tx,
772 	.stop_rx	= serial_pxa_stop_rx,
773 	.enable_ms	= serial_pxa_enable_ms,
774 	.break_ctl	= serial_pxa_break_ctl,
775 	.startup	= serial_pxa_startup,
776 	.shutdown	= serial_pxa_shutdown,
777 	.set_termios	= serial_pxa_set_termios,
778 	.pm		= serial_pxa_pm,
779 	.type		= serial_pxa_type,
780 	.release_port	= serial_pxa_release_port,
781 	.request_port	= serial_pxa_request_port,
782 	.config_port	= serial_pxa_config_port,
783 	.verify_port	= serial_pxa_verify_port,
784 #if defined(CONFIG_CONSOLE_POLL) && defined(CONFIG_SERIAL_PXA_CONSOLE)
785 	.poll_get_char = serial_pxa_get_poll_char,
786 	.poll_put_char = serial_pxa_put_poll_char,
787 #endif
788 };
789 
790 static struct uart_driver serial_pxa_reg = {
791 	.owner		= THIS_MODULE,
792 	.driver_name	= "PXA serial",
793 	.dev_name	= "ttyS",
794 	.major		= TTY_MAJOR,
795 	.minor		= 64,
796 	.nr		= 4,
797 	.cons		= PXA_CONSOLE,
798 };
799 
800 #ifdef CONFIG_PM
801 static int serial_pxa_suspend(struct device *dev)
802 {
803         struct uart_pxa_port *sport = dev_get_drvdata(dev);
804 
805         if (sport)
806                 uart_suspend_port(&serial_pxa_reg, &sport->port);
807 
808         return 0;
809 }
810 
811 static int serial_pxa_resume(struct device *dev)
812 {
813         struct uart_pxa_port *sport = dev_get_drvdata(dev);
814 
815         if (sport)
816                 uart_resume_port(&serial_pxa_reg, &sport->port);
817 
818         return 0;
819 }
820 
821 static const struct dev_pm_ops serial_pxa_pm_ops = {
822 	.suspend	= serial_pxa_suspend,
823 	.resume		= serial_pxa_resume,
824 };
825 #endif
826 
827 static const struct of_device_id serial_pxa_dt_ids[] = {
828 	{ .compatible = "mrvl,pxa-uart", },
829 	{ .compatible = "mrvl,mmp-uart", },
830 	{}
831 };
832 MODULE_DEVICE_TABLE(of, serial_pxa_dt_ids);
833 
834 static int serial_pxa_probe_dt(struct platform_device *pdev,
835 			       struct uart_pxa_port *sport)
836 {
837 	struct device_node *np = pdev->dev.of_node;
838 	int ret;
839 
840 	if (!np)
841 		return 1;
842 
843 	ret = of_alias_get_id(np, "serial");
844 	if (ret < 0) {
845 		dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
846 		return ret;
847 	}
848 	sport->port.line = ret;
849 	return 0;
850 }
851 
852 static int serial_pxa_probe(struct platform_device *dev)
853 {
854 	struct uart_pxa_port *sport;
855 	struct resource *mmres, *irqres;
856 	int ret;
857 
858 	mmres = platform_get_resource(dev, IORESOURCE_MEM, 0);
859 	irqres = platform_get_resource(dev, IORESOURCE_IRQ, 0);
860 	if (!mmres || !irqres)
861 		return -ENODEV;
862 
863 	sport = kzalloc(sizeof(struct uart_pxa_port), GFP_KERNEL);
864 	if (!sport)
865 		return -ENOMEM;
866 
867 	sport->clk = clk_get(&dev->dev, NULL);
868 	if (IS_ERR(sport->clk)) {
869 		ret = PTR_ERR(sport->clk);
870 		goto err_free;
871 	}
872 
873 	ret = clk_prepare(sport->clk);
874 	if (ret) {
875 		clk_put(sport->clk);
876 		goto err_free;
877 	}
878 
879 	sport->port.type = PORT_PXA;
880 	sport->port.iotype = UPIO_MEM;
881 	sport->port.mapbase = mmres->start;
882 	sport->port.irq = irqres->start;
883 	sport->port.fifosize = 64;
884 	sport->port.ops = &serial_pxa_pops;
885 	sport->port.dev = &dev->dev;
886 	sport->port.flags = UPF_IOREMAP | UPF_BOOT_AUTOCONF;
887 	sport->port.uartclk = clk_get_rate(sport->clk);
888 
889 	ret = serial_pxa_probe_dt(dev, sport);
890 	if (ret > 0)
891 		sport->port.line = dev->id;
892 	else if (ret < 0)
893 		goto err_clk;
894 	snprintf(sport->name, PXA_NAME_LEN - 1, "UART%d", sport->port.line + 1);
895 
896 	sport->port.membase = ioremap(mmres->start, resource_size(mmres));
897 	if (!sport->port.membase) {
898 		ret = -ENOMEM;
899 		goto err_clk;
900 	}
901 
902 	serial_pxa_ports[sport->port.line] = sport;
903 
904 	uart_add_one_port(&serial_pxa_reg, &sport->port);
905 	platform_set_drvdata(dev, sport);
906 
907 	return 0;
908 
909  err_clk:
910 	clk_unprepare(sport->clk);
911 	clk_put(sport->clk);
912  err_free:
913 	kfree(sport);
914 	return ret;
915 }
916 
917 static int serial_pxa_remove(struct platform_device *dev)
918 {
919 	struct uart_pxa_port *sport = platform_get_drvdata(dev);
920 
921 	uart_remove_one_port(&serial_pxa_reg, &sport->port);
922 
923 	clk_unprepare(sport->clk);
924 	clk_put(sport->clk);
925 	kfree(sport);
926 
927 	return 0;
928 }
929 
930 static struct platform_driver serial_pxa_driver = {
931         .probe          = serial_pxa_probe,
932         .remove         = serial_pxa_remove,
933 
934 	.driver		= {
935 	        .name	= "pxa2xx-uart",
936 #ifdef CONFIG_PM
937 		.pm	= &serial_pxa_pm_ops,
938 #endif
939 		.of_match_table = serial_pxa_dt_ids,
940 	},
941 };
942 
943 static int __init serial_pxa_init(void)
944 {
945 	int ret;
946 
947 	ret = uart_register_driver(&serial_pxa_reg);
948 	if (ret != 0)
949 		return ret;
950 
951 	ret = platform_driver_register(&serial_pxa_driver);
952 	if (ret != 0)
953 		uart_unregister_driver(&serial_pxa_reg);
954 
955 	return ret;
956 }
957 
958 static void __exit serial_pxa_exit(void)
959 {
960 	platform_driver_unregister(&serial_pxa_driver);
961 	uart_unregister_driver(&serial_pxa_reg);
962 }
963 
964 module_init(serial_pxa_init);
965 module_exit(serial_pxa_exit);
966 
967 MODULE_LICENSE("GPL");
968 MODULE_ALIAS("platform:pxa2xx-uart");
969