xref: /openbmc/linux/drivers/tty/serial/pxa.c (revision dd1431e5)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *  Based on drivers/serial/8250.c by Russell King.
4  *
5  *  Author:	Nicolas Pitre
6  *  Created:	Feb 20, 2003
7  *  Copyright:	(C) 2003 Monta Vista Software, Inc.
8  *
9  * Note 1: This driver is made separate from the already too overloaded
10  * 8250.c because it needs some kirks of its own and that'll make it
11  * easier to add DMA support.
12  *
13  * Note 2: I'm too sick of device allocation policies for serial ports.
14  * If someone else wants to request an "official" allocation of major/minor
15  * for this driver please be my guest.  And don't forget that new hardware
16  * to come from Intel might have more than 3 or 4 of those UARTs.  Let's
17  * hope for a better port registration and dynamic device allocation scheme
18  * with the serial core maintainer satisfaction to appear soon.
19  */
20 
21 
22 #include <linux/ioport.h>
23 #include <linux/init.h>
24 #include <linux/console.h>
25 #include <linux/sysrq.h>
26 #include <linux/serial_reg.h>
27 #include <linux/circ_buf.h>
28 #include <linux/delay.h>
29 #include <linux/interrupt.h>
30 #include <linux/of.h>
31 #include <linux/platform_device.h>
32 #include <linux/tty.h>
33 #include <linux/tty_flip.h>
34 #include <linux/serial_core.h>
35 #include <linux/clk.h>
36 #include <linux/io.h>
37 #include <linux/slab.h>
38 
39 #define PXA_NAME_LEN		8
40 
41 struct uart_pxa_port {
42 	struct uart_port        port;
43 	unsigned char           ier;
44 	unsigned char           lcr;
45 	unsigned char           mcr;
46 	unsigned int            lsr_break_flag;
47 	struct clk		*clk;
48 	char			name[PXA_NAME_LEN];
49 };
50 
51 static inline unsigned int serial_in(struct uart_pxa_port *up, int offset)
52 {
53 	offset <<= 2;
54 	return readl(up->port.membase + offset);
55 }
56 
57 static inline void serial_out(struct uart_pxa_port *up, int offset, int value)
58 {
59 	offset <<= 2;
60 	writel(value, up->port.membase + offset);
61 }
62 
63 static void serial_pxa_enable_ms(struct uart_port *port)
64 {
65 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
66 
67 	up->ier |= UART_IER_MSI;
68 	serial_out(up, UART_IER, up->ier);
69 }
70 
71 static void serial_pxa_stop_tx(struct uart_port *port)
72 {
73 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
74 
75 	if (up->ier & UART_IER_THRI) {
76 		up->ier &= ~UART_IER_THRI;
77 		serial_out(up, UART_IER, up->ier);
78 	}
79 }
80 
81 static void serial_pxa_stop_rx(struct uart_port *port)
82 {
83 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
84 
85 	up->ier &= ~UART_IER_RLSI;
86 	up->port.read_status_mask &= ~UART_LSR_DR;
87 	serial_out(up, UART_IER, up->ier);
88 }
89 
90 static inline void receive_chars(struct uart_pxa_port *up, int *status)
91 {
92 	unsigned int ch, flag;
93 	int max_count = 256;
94 
95 	do {
96 		/* work around Errata #20 according to
97 		 * Intel(R) PXA27x Processor Family
98 		 * Specification Update (May 2005)
99 		 *
100 		 * Step 2
101 		 * Disable the Reciever Time Out Interrupt via IER[RTOEI]
102 		 */
103 		up->ier &= ~UART_IER_RTOIE;
104 		serial_out(up, UART_IER, up->ier);
105 
106 		ch = serial_in(up, UART_RX);
107 		flag = TTY_NORMAL;
108 		up->port.icount.rx++;
109 
110 		if (unlikely(*status & (UART_LSR_BI | UART_LSR_PE |
111 				       UART_LSR_FE | UART_LSR_OE))) {
112 			/*
113 			 * For statistics only
114 			 */
115 			if (*status & UART_LSR_BI) {
116 				*status &= ~(UART_LSR_FE | UART_LSR_PE);
117 				up->port.icount.brk++;
118 				/*
119 				 * We do the SysRQ and SAK checking
120 				 * here because otherwise the break
121 				 * may get masked by ignore_status_mask
122 				 * or read_status_mask.
123 				 */
124 				if (uart_handle_break(&up->port))
125 					goto ignore_char;
126 			} else if (*status & UART_LSR_PE)
127 				up->port.icount.parity++;
128 			else if (*status & UART_LSR_FE)
129 				up->port.icount.frame++;
130 			if (*status & UART_LSR_OE)
131 				up->port.icount.overrun++;
132 
133 			/*
134 			 * Mask off conditions which should be ignored.
135 			 */
136 			*status &= up->port.read_status_mask;
137 
138 #ifdef CONFIG_SERIAL_PXA_CONSOLE
139 			if (up->port.line == up->port.cons->index) {
140 				/* Recover the break flag from console xmit */
141 				*status |= up->lsr_break_flag;
142 				up->lsr_break_flag = 0;
143 			}
144 #endif
145 			if (*status & UART_LSR_BI) {
146 				flag = TTY_BREAK;
147 			} else if (*status & UART_LSR_PE)
148 				flag = TTY_PARITY;
149 			else if (*status & UART_LSR_FE)
150 				flag = TTY_FRAME;
151 		}
152 
153 		if (uart_handle_sysrq_char(&up->port, ch))
154 			goto ignore_char;
155 
156 		uart_insert_char(&up->port, *status, UART_LSR_OE, ch, flag);
157 
158 	ignore_char:
159 		*status = serial_in(up, UART_LSR);
160 	} while ((*status & UART_LSR_DR) && (max_count-- > 0));
161 	tty_flip_buffer_push(&up->port.state->port);
162 
163 	/* work around Errata #20 according to
164 	 * Intel(R) PXA27x Processor Family
165 	 * Specification Update (May 2005)
166 	 *
167 	 * Step 6:
168 	 * No more data in FIFO: Re-enable RTO interrupt via IER[RTOIE]
169 	 */
170 	up->ier |= UART_IER_RTOIE;
171 	serial_out(up, UART_IER, up->ier);
172 }
173 
174 static void transmit_chars(struct uart_pxa_port *up)
175 {
176 	struct circ_buf *xmit = &up->port.state->xmit;
177 	int count;
178 
179 	if (up->port.x_char) {
180 		serial_out(up, UART_TX, up->port.x_char);
181 		up->port.icount.tx++;
182 		up->port.x_char = 0;
183 		return;
184 	}
185 	if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) {
186 		serial_pxa_stop_tx(&up->port);
187 		return;
188 	}
189 
190 	count = up->port.fifosize / 2;
191 	do {
192 		serial_out(up, UART_TX, xmit->buf[xmit->tail]);
193 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
194 		up->port.icount.tx++;
195 		if (uart_circ_empty(xmit))
196 			break;
197 	} while (--count > 0);
198 
199 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
200 		uart_write_wakeup(&up->port);
201 
202 
203 	if (uart_circ_empty(xmit))
204 		serial_pxa_stop_tx(&up->port);
205 }
206 
207 static void serial_pxa_start_tx(struct uart_port *port)
208 {
209 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
210 
211 	if (!(up->ier & UART_IER_THRI)) {
212 		up->ier |= UART_IER_THRI;
213 		serial_out(up, UART_IER, up->ier);
214 	}
215 }
216 
217 /* should hold up->port.lock */
218 static inline void check_modem_status(struct uart_pxa_port *up)
219 {
220 	int status;
221 
222 	status = serial_in(up, UART_MSR);
223 
224 	if ((status & UART_MSR_ANY_DELTA) == 0)
225 		return;
226 
227 	if (status & UART_MSR_TERI)
228 		up->port.icount.rng++;
229 	if (status & UART_MSR_DDSR)
230 		up->port.icount.dsr++;
231 	if (status & UART_MSR_DDCD)
232 		uart_handle_dcd_change(&up->port, status & UART_MSR_DCD);
233 	if (status & UART_MSR_DCTS)
234 		uart_handle_cts_change(&up->port, status & UART_MSR_CTS);
235 
236 	wake_up_interruptible(&up->port.state->port.delta_msr_wait);
237 }
238 
239 /*
240  * This handles the interrupt from one port.
241  */
242 static inline irqreturn_t serial_pxa_irq(int irq, void *dev_id)
243 {
244 	struct uart_pxa_port *up = dev_id;
245 	unsigned int iir, lsr;
246 
247 	iir = serial_in(up, UART_IIR);
248 	if (iir & UART_IIR_NO_INT)
249 		return IRQ_NONE;
250 	spin_lock(&up->port.lock);
251 	lsr = serial_in(up, UART_LSR);
252 	if (lsr & UART_LSR_DR)
253 		receive_chars(up, &lsr);
254 	check_modem_status(up);
255 	if (lsr & UART_LSR_THRE)
256 		transmit_chars(up);
257 	spin_unlock(&up->port.lock);
258 	return IRQ_HANDLED;
259 }
260 
261 static unsigned int serial_pxa_tx_empty(struct uart_port *port)
262 {
263 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
264 	unsigned long flags;
265 	unsigned int ret;
266 
267 	spin_lock_irqsave(&up->port.lock, flags);
268 	ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
269 	spin_unlock_irqrestore(&up->port.lock, flags);
270 
271 	return ret;
272 }
273 
274 static unsigned int serial_pxa_get_mctrl(struct uart_port *port)
275 {
276 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
277 	unsigned char status;
278 	unsigned int ret;
279 
280 	status = serial_in(up, UART_MSR);
281 
282 	ret = 0;
283 	if (status & UART_MSR_DCD)
284 		ret |= TIOCM_CAR;
285 	if (status & UART_MSR_RI)
286 		ret |= TIOCM_RNG;
287 	if (status & UART_MSR_DSR)
288 		ret |= TIOCM_DSR;
289 	if (status & UART_MSR_CTS)
290 		ret |= TIOCM_CTS;
291 	return ret;
292 }
293 
294 static void serial_pxa_set_mctrl(struct uart_port *port, unsigned int mctrl)
295 {
296 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
297 	unsigned char mcr = 0;
298 
299 	if (mctrl & TIOCM_RTS)
300 		mcr |= UART_MCR_RTS;
301 	if (mctrl & TIOCM_DTR)
302 		mcr |= UART_MCR_DTR;
303 	if (mctrl & TIOCM_OUT1)
304 		mcr |= UART_MCR_OUT1;
305 	if (mctrl & TIOCM_OUT2)
306 		mcr |= UART_MCR_OUT2;
307 	if (mctrl & TIOCM_LOOP)
308 		mcr |= UART_MCR_LOOP;
309 
310 	mcr |= up->mcr;
311 
312 	serial_out(up, UART_MCR, mcr);
313 }
314 
315 static void serial_pxa_break_ctl(struct uart_port *port, int break_state)
316 {
317 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
318 	unsigned long flags;
319 
320 	spin_lock_irqsave(&up->port.lock, flags);
321 	if (break_state == -1)
322 		up->lcr |= UART_LCR_SBC;
323 	else
324 		up->lcr &= ~UART_LCR_SBC;
325 	serial_out(up, UART_LCR, up->lcr);
326 	spin_unlock_irqrestore(&up->port.lock, flags);
327 }
328 
329 static int serial_pxa_startup(struct uart_port *port)
330 {
331 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
332 	unsigned long flags;
333 	int retval;
334 
335 	if (port->line == 3) /* HWUART */
336 		up->mcr |= UART_MCR_AFE;
337 	else
338 		up->mcr = 0;
339 
340 	up->port.uartclk = clk_get_rate(up->clk);
341 
342 	/*
343 	 * Allocate the IRQ
344 	 */
345 	retval = request_irq(up->port.irq, serial_pxa_irq, 0, up->name, up);
346 	if (retval)
347 		return retval;
348 
349 	/*
350 	 * Clear the FIFO buffers and disable them.
351 	 * (they will be reenabled in set_termios())
352 	 */
353 	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
354 	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
355 			UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
356 	serial_out(up, UART_FCR, 0);
357 
358 	/*
359 	 * Clear the interrupt registers.
360 	 */
361 	(void) serial_in(up, UART_LSR);
362 	(void) serial_in(up, UART_RX);
363 	(void) serial_in(up, UART_IIR);
364 	(void) serial_in(up, UART_MSR);
365 
366 	/*
367 	 * Now, initialize the UART
368 	 */
369 	serial_out(up, UART_LCR, UART_LCR_WLEN8);
370 
371 	spin_lock_irqsave(&up->port.lock, flags);
372 	up->port.mctrl |= TIOCM_OUT2;
373 	serial_pxa_set_mctrl(&up->port, up->port.mctrl);
374 	spin_unlock_irqrestore(&up->port.lock, flags);
375 
376 	/*
377 	 * Finally, enable interrupts.  Note: Modem status interrupts
378 	 * are set via set_termios(), which will be occurring imminently
379 	 * anyway, so we don't enable them here.
380 	 */
381 	up->ier = UART_IER_RLSI | UART_IER_RDI | UART_IER_RTOIE | UART_IER_UUE;
382 	serial_out(up, UART_IER, up->ier);
383 
384 	/*
385 	 * And clear the interrupt registers again for luck.
386 	 */
387 	(void) serial_in(up, UART_LSR);
388 	(void) serial_in(up, UART_RX);
389 	(void) serial_in(up, UART_IIR);
390 	(void) serial_in(up, UART_MSR);
391 
392 	return 0;
393 }
394 
395 static void serial_pxa_shutdown(struct uart_port *port)
396 {
397 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
398 	unsigned long flags;
399 
400 	free_irq(up->port.irq, up);
401 
402 	/*
403 	 * Disable interrupts from this port
404 	 */
405 	up->ier = 0;
406 	serial_out(up, UART_IER, 0);
407 
408 	spin_lock_irqsave(&up->port.lock, flags);
409 	up->port.mctrl &= ~TIOCM_OUT2;
410 	serial_pxa_set_mctrl(&up->port, up->port.mctrl);
411 	spin_unlock_irqrestore(&up->port.lock, flags);
412 
413 	/*
414 	 * Disable break condition and FIFOs
415 	 */
416 	serial_out(up, UART_LCR, serial_in(up, UART_LCR) & ~UART_LCR_SBC);
417 	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
418 				  UART_FCR_CLEAR_RCVR |
419 				  UART_FCR_CLEAR_XMIT);
420 	serial_out(up, UART_FCR, 0);
421 }
422 
423 static void
424 serial_pxa_set_termios(struct uart_port *port, struct ktermios *termios,
425 		       struct ktermios *old)
426 {
427 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
428 	unsigned char cval, fcr = 0;
429 	unsigned long flags;
430 	unsigned int baud, quot;
431 	unsigned int dll;
432 
433 	switch (termios->c_cflag & CSIZE) {
434 	case CS5:
435 		cval = UART_LCR_WLEN5;
436 		break;
437 	case CS6:
438 		cval = UART_LCR_WLEN6;
439 		break;
440 	case CS7:
441 		cval = UART_LCR_WLEN7;
442 		break;
443 	default:
444 	case CS8:
445 		cval = UART_LCR_WLEN8;
446 		break;
447 	}
448 
449 	if (termios->c_cflag & CSTOPB)
450 		cval |= UART_LCR_STOP;
451 	if (termios->c_cflag & PARENB)
452 		cval |= UART_LCR_PARITY;
453 	if (!(termios->c_cflag & PARODD))
454 		cval |= UART_LCR_EPAR;
455 
456 	/*
457 	 * Ask the core to calculate the divisor for us.
458 	 */
459 	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
460 	quot = uart_get_divisor(port, baud);
461 
462 	if ((up->port.uartclk / quot) < (2400 * 16))
463 		fcr = UART_FCR_ENABLE_FIFO | UART_FCR_PXAR1;
464 	else if ((up->port.uartclk / quot) < (230400 * 16))
465 		fcr = UART_FCR_ENABLE_FIFO | UART_FCR_PXAR8;
466 	else
467 		fcr = UART_FCR_ENABLE_FIFO | UART_FCR_PXAR32;
468 
469 	/*
470 	 * Ok, we're now changing the port state.  Do it with
471 	 * interrupts disabled.
472 	 */
473 	spin_lock_irqsave(&up->port.lock, flags);
474 
475 	/*
476 	 * Ensure the port will be enabled.
477 	 * This is required especially for serial console.
478 	 */
479 	up->ier |= UART_IER_UUE;
480 
481 	/*
482 	 * Update the per-port timeout.
483 	 */
484 	uart_update_timeout(port, termios->c_cflag, baud);
485 
486 	up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
487 	if (termios->c_iflag & INPCK)
488 		up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
489 	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
490 		up->port.read_status_mask |= UART_LSR_BI;
491 
492 	/*
493 	 * Characters to ignore
494 	 */
495 	up->port.ignore_status_mask = 0;
496 	if (termios->c_iflag & IGNPAR)
497 		up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
498 	if (termios->c_iflag & IGNBRK) {
499 		up->port.ignore_status_mask |= UART_LSR_BI;
500 		/*
501 		 * If we're ignoring parity and break indicators,
502 		 * ignore overruns too (for real raw support).
503 		 */
504 		if (termios->c_iflag & IGNPAR)
505 			up->port.ignore_status_mask |= UART_LSR_OE;
506 	}
507 
508 	/*
509 	 * ignore all characters if CREAD is not set
510 	 */
511 	if ((termios->c_cflag & CREAD) == 0)
512 		up->port.ignore_status_mask |= UART_LSR_DR;
513 
514 	/*
515 	 * CTS flow control flag and modem status interrupts
516 	 */
517 	up->ier &= ~UART_IER_MSI;
518 	if (UART_ENABLE_MS(&up->port, termios->c_cflag))
519 		up->ier |= UART_IER_MSI;
520 
521 	serial_out(up, UART_IER, up->ier);
522 
523 	if (termios->c_cflag & CRTSCTS)
524 		up->mcr |= UART_MCR_AFE;
525 	else
526 		up->mcr &= ~UART_MCR_AFE;
527 
528 	serial_out(up, UART_LCR, cval | UART_LCR_DLAB);	/* set DLAB */
529 	serial_out(up, UART_DLL, quot & 0xff);		/* LS of divisor */
530 
531 	/*
532 	 * work around Errata #75 according to Intel(R) PXA27x Processor Family
533 	 * Specification Update (Nov 2005)
534 	 */
535 	dll = serial_in(up, UART_DLL);
536 	WARN_ON(dll != (quot & 0xff));
537 
538 	serial_out(up, UART_DLM, quot >> 8);		/* MS of divisor */
539 	serial_out(up, UART_LCR, cval);			/* reset DLAB */
540 	up->lcr = cval;					/* Save LCR */
541 	serial_pxa_set_mctrl(&up->port, up->port.mctrl);
542 	serial_out(up, UART_FCR, fcr);
543 	spin_unlock_irqrestore(&up->port.lock, flags);
544 }
545 
546 static void
547 serial_pxa_pm(struct uart_port *port, unsigned int state,
548 	      unsigned int oldstate)
549 {
550 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
551 
552 	if (!state)
553 		clk_prepare_enable(up->clk);
554 	else
555 		clk_disable_unprepare(up->clk);
556 }
557 
558 static void serial_pxa_release_port(struct uart_port *port)
559 {
560 }
561 
562 static int serial_pxa_request_port(struct uart_port *port)
563 {
564 	return 0;
565 }
566 
567 static void serial_pxa_config_port(struct uart_port *port, int flags)
568 {
569 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
570 	up->port.type = PORT_PXA;
571 }
572 
573 static int
574 serial_pxa_verify_port(struct uart_port *port, struct serial_struct *ser)
575 {
576 	/* we don't want the core code to modify any port params */
577 	return -EINVAL;
578 }
579 
580 static const char *
581 serial_pxa_type(struct uart_port *port)
582 {
583 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
584 	return up->name;
585 }
586 
587 static struct uart_pxa_port *serial_pxa_ports[4];
588 static struct uart_driver serial_pxa_reg;
589 
590 #ifdef CONFIG_SERIAL_PXA_CONSOLE
591 
592 #define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
593 
594 /*
595  *	Wait for transmitter & holding register to empty
596  */
597 static void wait_for_xmitr(struct uart_pxa_port *up)
598 {
599 	unsigned int status, tmout = 10000;
600 
601 	/* Wait up to 10ms for the character(s) to be sent. */
602 	do {
603 		status = serial_in(up, UART_LSR);
604 
605 		if (status & UART_LSR_BI)
606 			up->lsr_break_flag = UART_LSR_BI;
607 
608 		if (--tmout == 0)
609 			break;
610 		udelay(1);
611 	} while ((status & BOTH_EMPTY) != BOTH_EMPTY);
612 
613 	/* Wait up to 1s for flow control if necessary */
614 	if (up->port.flags & UPF_CONS_FLOW) {
615 		tmout = 1000000;
616 		while (--tmout &&
617 		       ((serial_in(up, UART_MSR) & UART_MSR_CTS) == 0))
618 			udelay(1);
619 	}
620 }
621 
622 static void serial_pxa_console_putchar(struct uart_port *port, int ch)
623 {
624 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
625 
626 	wait_for_xmitr(up);
627 	serial_out(up, UART_TX, ch);
628 }
629 
630 /*
631  * Print a string to the serial port trying not to disturb
632  * any possible real use of the port...
633  *
634  *	The console_lock must be held when we get here.
635  */
636 static void
637 serial_pxa_console_write(struct console *co, const char *s, unsigned int count)
638 {
639 	struct uart_pxa_port *up = serial_pxa_ports[co->index];
640 	unsigned int ier;
641 	unsigned long flags;
642 	int locked = 1;
643 
644 	clk_enable(up->clk);
645 	local_irq_save(flags);
646 	if (up->port.sysrq)
647 		locked = 0;
648 	else if (oops_in_progress)
649 		locked = spin_trylock(&up->port.lock);
650 	else
651 		spin_lock(&up->port.lock);
652 
653 	/*
654 	 *	First save the IER then disable the interrupts
655 	 */
656 	ier = serial_in(up, UART_IER);
657 	serial_out(up, UART_IER, UART_IER_UUE);
658 
659 	uart_console_write(&up->port, s, count, serial_pxa_console_putchar);
660 
661 	/*
662 	 *	Finally, wait for transmitter to become empty
663 	 *	and restore the IER
664 	 */
665 	wait_for_xmitr(up);
666 	serial_out(up, UART_IER, ier);
667 
668 	if (locked)
669 		spin_unlock(&up->port.lock);
670 	local_irq_restore(flags);
671 	clk_disable(up->clk);
672 
673 }
674 
675 #ifdef CONFIG_CONSOLE_POLL
676 /*
677  * Console polling routines for writing and reading from the uart while
678  * in an interrupt or debug context.
679  */
680 
681 static int serial_pxa_get_poll_char(struct uart_port *port)
682 {
683 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
684 	unsigned char lsr = serial_in(up, UART_LSR);
685 
686 	while (!(lsr & UART_LSR_DR))
687 		lsr = serial_in(up, UART_LSR);
688 
689 	return serial_in(up, UART_RX);
690 }
691 
692 
693 static void serial_pxa_put_poll_char(struct uart_port *port,
694 			 unsigned char c)
695 {
696 	unsigned int ier;
697 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
698 
699 	/*
700 	 *	First save the IER then disable the interrupts
701 	 */
702 	ier = serial_in(up, UART_IER);
703 	serial_out(up, UART_IER, UART_IER_UUE);
704 
705 	wait_for_xmitr(up);
706 	/*
707 	 *	Send the character out.
708 	 */
709 	serial_out(up, UART_TX, c);
710 
711 	/*
712 	 *	Finally, wait for transmitter to become empty
713 	 *	and restore the IER
714 	 */
715 	wait_for_xmitr(up);
716 	serial_out(up, UART_IER, ier);
717 }
718 
719 #endif /* CONFIG_CONSOLE_POLL */
720 
721 static int __init
722 serial_pxa_console_setup(struct console *co, char *options)
723 {
724 	struct uart_pxa_port *up;
725 	int baud = 9600;
726 	int bits = 8;
727 	int parity = 'n';
728 	int flow = 'n';
729 
730 	if (co->index == -1 || co->index >= serial_pxa_reg.nr)
731 		co->index = 0;
732 	up = serial_pxa_ports[co->index];
733 	if (!up)
734 		return -ENODEV;
735 
736 	if (options)
737 		uart_parse_options(options, &baud, &parity, &bits, &flow);
738 
739 	return uart_set_options(&up->port, co, baud, parity, bits, flow);
740 }
741 
742 static struct console serial_pxa_console = {
743 	.name		= "ttyS",
744 	.write		= serial_pxa_console_write,
745 	.device		= uart_console_device,
746 	.setup		= serial_pxa_console_setup,
747 	.flags		= CON_PRINTBUFFER,
748 	.index		= -1,
749 	.data		= &serial_pxa_reg,
750 };
751 
752 #define PXA_CONSOLE	&serial_pxa_console
753 #else
754 #define PXA_CONSOLE	NULL
755 #endif
756 
757 static const struct uart_ops serial_pxa_pops = {
758 	.tx_empty	= serial_pxa_tx_empty,
759 	.set_mctrl	= serial_pxa_set_mctrl,
760 	.get_mctrl	= serial_pxa_get_mctrl,
761 	.stop_tx	= serial_pxa_stop_tx,
762 	.start_tx	= serial_pxa_start_tx,
763 	.stop_rx	= serial_pxa_stop_rx,
764 	.enable_ms	= serial_pxa_enable_ms,
765 	.break_ctl	= serial_pxa_break_ctl,
766 	.startup	= serial_pxa_startup,
767 	.shutdown	= serial_pxa_shutdown,
768 	.set_termios	= serial_pxa_set_termios,
769 	.pm		= serial_pxa_pm,
770 	.type		= serial_pxa_type,
771 	.release_port	= serial_pxa_release_port,
772 	.request_port	= serial_pxa_request_port,
773 	.config_port	= serial_pxa_config_port,
774 	.verify_port	= serial_pxa_verify_port,
775 #if defined(CONFIG_CONSOLE_POLL) && defined(CONFIG_SERIAL_PXA_CONSOLE)
776 	.poll_get_char = serial_pxa_get_poll_char,
777 	.poll_put_char = serial_pxa_put_poll_char,
778 #endif
779 };
780 
781 static struct uart_driver serial_pxa_reg = {
782 	.owner		= THIS_MODULE,
783 	.driver_name	= "PXA serial",
784 	.dev_name	= "ttyS",
785 	.major		= TTY_MAJOR,
786 	.minor		= 64,
787 	.nr		= 4,
788 	.cons		= PXA_CONSOLE,
789 };
790 
791 #ifdef CONFIG_PM
792 static int serial_pxa_suspend(struct device *dev)
793 {
794         struct uart_pxa_port *sport = dev_get_drvdata(dev);
795 
796         if (sport)
797                 uart_suspend_port(&serial_pxa_reg, &sport->port);
798 
799         return 0;
800 }
801 
802 static int serial_pxa_resume(struct device *dev)
803 {
804         struct uart_pxa_port *sport = dev_get_drvdata(dev);
805 
806         if (sport)
807                 uart_resume_port(&serial_pxa_reg, &sport->port);
808 
809         return 0;
810 }
811 
812 static const struct dev_pm_ops serial_pxa_pm_ops = {
813 	.suspend	= serial_pxa_suspend,
814 	.resume		= serial_pxa_resume,
815 };
816 #endif
817 
818 static const struct of_device_id serial_pxa_dt_ids[] = {
819 	{ .compatible = "mrvl,pxa-uart", },
820 	{ .compatible = "mrvl,mmp-uart", },
821 	{}
822 };
823 
824 static int serial_pxa_probe_dt(struct platform_device *pdev,
825 			       struct uart_pxa_port *sport)
826 {
827 	struct device_node *np = pdev->dev.of_node;
828 	int ret;
829 
830 	if (!np)
831 		return 1;
832 
833 	ret = of_alias_get_id(np, "serial");
834 	if (ret < 0) {
835 		dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
836 		return ret;
837 	}
838 	sport->port.line = ret;
839 	return 0;
840 }
841 
842 static int serial_pxa_probe(struct platform_device *dev)
843 {
844 	struct uart_pxa_port *sport;
845 	struct resource *mmres, *irqres;
846 	int ret;
847 
848 	mmres = platform_get_resource(dev, IORESOURCE_MEM, 0);
849 	irqres = platform_get_resource(dev, IORESOURCE_IRQ, 0);
850 	if (!mmres || !irqres)
851 		return -ENODEV;
852 
853 	sport = kzalloc(sizeof(struct uart_pxa_port), GFP_KERNEL);
854 	if (!sport)
855 		return -ENOMEM;
856 
857 	sport->clk = clk_get(&dev->dev, NULL);
858 	if (IS_ERR(sport->clk)) {
859 		ret = PTR_ERR(sport->clk);
860 		goto err_free;
861 	}
862 
863 	ret = clk_prepare(sport->clk);
864 	if (ret) {
865 		clk_put(sport->clk);
866 		goto err_free;
867 	}
868 
869 	sport->port.type = PORT_PXA;
870 	sport->port.iotype = UPIO_MEM;
871 	sport->port.mapbase = mmres->start;
872 	sport->port.irq = irqres->start;
873 	sport->port.fifosize = 64;
874 	sport->port.ops = &serial_pxa_pops;
875 	sport->port.dev = &dev->dev;
876 	sport->port.flags = UPF_IOREMAP | UPF_BOOT_AUTOCONF;
877 	sport->port.uartclk = clk_get_rate(sport->clk);
878 	sport->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_PXA_CONSOLE);
879 
880 	ret = serial_pxa_probe_dt(dev, sport);
881 	if (ret > 0)
882 		sport->port.line = dev->id;
883 	else if (ret < 0)
884 		goto err_clk;
885 	if (sport->port.line >= ARRAY_SIZE(serial_pxa_ports)) {
886 		dev_err(&dev->dev, "serial%d out of range\n", sport->port.line);
887 		ret = -EINVAL;
888 		goto err_clk;
889 	}
890 	snprintf(sport->name, PXA_NAME_LEN - 1, "UART%d", sport->port.line + 1);
891 
892 	sport->port.membase = ioremap(mmres->start, resource_size(mmres));
893 	if (!sport->port.membase) {
894 		ret = -ENOMEM;
895 		goto err_clk;
896 	}
897 
898 	serial_pxa_ports[sport->port.line] = sport;
899 
900 	uart_add_one_port(&serial_pxa_reg, &sport->port);
901 	platform_set_drvdata(dev, sport);
902 
903 	return 0;
904 
905  err_clk:
906 	clk_unprepare(sport->clk);
907 	clk_put(sport->clk);
908  err_free:
909 	kfree(sport);
910 	return ret;
911 }
912 
913 static struct platform_driver serial_pxa_driver = {
914         .probe          = serial_pxa_probe,
915 
916 	.driver		= {
917 	        .name	= "pxa2xx-uart",
918 #ifdef CONFIG_PM
919 		.pm	= &serial_pxa_pm_ops,
920 #endif
921 		.suppress_bind_attrs = true,
922 		.of_match_table = serial_pxa_dt_ids,
923 	},
924 };
925 
926 
927 /* 8250 driver for PXA serial ports should be used */
928 static int __init serial_pxa_init(void)
929 {
930 	int ret;
931 
932 	ret = uart_register_driver(&serial_pxa_reg);
933 	if (ret != 0)
934 		return ret;
935 
936 	ret = platform_driver_register(&serial_pxa_driver);
937 	if (ret != 0)
938 		uart_unregister_driver(&serial_pxa_reg);
939 
940 	return ret;
941 }
942 device_initcall(serial_pxa_init);
943