1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Freescale LINFlexD UART serial port driver
4  *
5  * Copyright 2012-2016 Freescale Semiconductor, Inc.
6  * Copyright 2017-2019 NXP
7  */
8 
9 #include <linux/console.h>
10 #include <linux/io.h>
11 #include <linux/irq.h>
12 #include <linux/module.h>
13 #include <linux/of.h>
14 #include <linux/of_device.h>
15 #include <linux/serial_core.h>
16 #include <linux/slab.h>
17 #include <linux/tty_flip.h>
18 #include <linux/delay.h>
19 
20 /* All registers are 32-bit width */
21 
22 #define LINCR1	0x0000	/* LIN control register				*/
23 #define LINIER	0x0004	/* LIN interrupt enable register		*/
24 #define LINSR	0x0008	/* LIN status register				*/
25 #define LINESR	0x000C	/* LIN error status register			*/
26 #define UARTCR	0x0010	/* UART mode control register			*/
27 #define UARTSR	0x0014	/* UART mode status register			*/
28 #define LINTCSR	0x0018	/* LIN timeout control status register		*/
29 #define LINOCR	0x001C	/* LIN output compare register			*/
30 #define LINTOCR	0x0020	/* LIN timeout control register			*/
31 #define LINFBRR	0x0024	/* LIN fractional baud rate register		*/
32 #define LINIBRR	0x0028	/* LIN integer baud rate register		*/
33 #define LINCFR	0x002C	/* LIN checksum field register			*/
34 #define LINCR2	0x0030	/* LIN control register 2			*/
35 #define BIDR	0x0034	/* Buffer identifier register			*/
36 #define BDRL	0x0038	/* Buffer data register least significant	*/
37 #define BDRM	0x003C	/* Buffer data register most significant	*/
38 #define IFER	0x0040	/* Identifier filter enable register		*/
39 #define IFMI	0x0044	/* Identifier filter match index		*/
40 #define IFMR	0x0048	/* Identifier filter mode register		*/
41 #define GCR	0x004C	/* Global control register			*/
42 #define UARTPTO	0x0050	/* UART preset timeout register			*/
43 #define UARTCTO	0x0054	/* UART current timeout register		*/
44 
45 /*
46  * Register field definitions
47  */
48 
49 #define LINFLEXD_LINCR1_INIT		BIT(0)
50 #define LINFLEXD_LINCR1_MME		BIT(4)
51 #define LINFLEXD_LINCR1_BF		BIT(7)
52 
53 #define LINFLEXD_LINSR_LINS_INITMODE	BIT(12)
54 #define LINFLEXD_LINSR_LINS_MASK	(0xF << 12)
55 
56 #define LINFLEXD_LINIER_SZIE		BIT(15)
57 #define LINFLEXD_LINIER_OCIE		BIT(14)
58 #define LINFLEXD_LINIER_BEIE		BIT(13)
59 #define LINFLEXD_LINIER_CEIE		BIT(12)
60 #define LINFLEXD_LINIER_HEIE		BIT(11)
61 #define LINFLEXD_LINIER_FEIE		BIT(8)
62 #define LINFLEXD_LINIER_BOIE		BIT(7)
63 #define LINFLEXD_LINIER_LSIE		BIT(6)
64 #define LINFLEXD_LINIER_WUIE		BIT(5)
65 #define LINFLEXD_LINIER_DBFIE		BIT(4)
66 #define LINFLEXD_LINIER_DBEIETOIE	BIT(3)
67 #define LINFLEXD_LINIER_DRIE		BIT(2)
68 #define LINFLEXD_LINIER_DTIE		BIT(1)
69 #define LINFLEXD_LINIER_HRIE		BIT(0)
70 
71 #define LINFLEXD_UARTCR_OSR_MASK	(0xF << 24)
72 #define LINFLEXD_UARTCR_OSR(uartcr)	(((uartcr) \
73 					& LINFLEXD_UARTCR_OSR_MASK) >> 24)
74 
75 #define LINFLEXD_UARTCR_ROSE		BIT(23)
76 
77 #define LINFLEXD_UARTCR_RFBM		BIT(9)
78 #define LINFLEXD_UARTCR_TFBM		BIT(8)
79 #define LINFLEXD_UARTCR_WL1		BIT(7)
80 #define LINFLEXD_UARTCR_PC1		BIT(6)
81 
82 #define LINFLEXD_UARTCR_RXEN		BIT(5)
83 #define LINFLEXD_UARTCR_TXEN		BIT(4)
84 #define LINFLEXD_UARTCR_PC0		BIT(3)
85 
86 #define LINFLEXD_UARTCR_PCE		BIT(2)
87 #define LINFLEXD_UARTCR_WL0		BIT(1)
88 #define LINFLEXD_UARTCR_UART		BIT(0)
89 
90 #define LINFLEXD_UARTSR_SZF		BIT(15)
91 #define LINFLEXD_UARTSR_OCF		BIT(14)
92 #define LINFLEXD_UARTSR_PE3		BIT(13)
93 #define LINFLEXD_UARTSR_PE2		BIT(12)
94 #define LINFLEXD_UARTSR_PE1		BIT(11)
95 #define LINFLEXD_UARTSR_PE0		BIT(10)
96 #define LINFLEXD_UARTSR_RMB		BIT(9)
97 #define LINFLEXD_UARTSR_FEF		BIT(8)
98 #define LINFLEXD_UARTSR_BOF		BIT(7)
99 #define LINFLEXD_UARTSR_RPS		BIT(6)
100 #define LINFLEXD_UARTSR_WUF		BIT(5)
101 #define LINFLEXD_UARTSR_4		BIT(4)
102 
103 #define LINFLEXD_UARTSR_TO		BIT(3)
104 
105 #define LINFLEXD_UARTSR_DRFRFE		BIT(2)
106 #define LINFLEXD_UARTSR_DTFTFF		BIT(1)
107 #define LINFLEXD_UARTSR_NF		BIT(0)
108 #define LINFLEXD_UARTSR_PE		(LINFLEXD_UARTSR_PE0 |\
109 					 LINFLEXD_UARTSR_PE1 |\
110 					 LINFLEXD_UARTSR_PE2 |\
111 					 LINFLEXD_UARTSR_PE3)
112 
113 #define LINFLEX_LDIV_MULTIPLIER		(16)
114 
115 #define DRIVER_NAME	"fsl-linflexuart"
116 #define DEV_NAME	"ttyLF"
117 #define UART_NR		4
118 
119 #define EARLYCON_BUFFER_INITIAL_CAP	8
120 
121 #define PREINIT_DELAY			2000 /* us */
122 
123 static const struct of_device_id linflex_dt_ids[] = {
124 	{
125 		.compatible = "fsl,s32v234-linflexuart",
126 	},
127 	{ /* sentinel */ }
128 };
129 MODULE_DEVICE_TABLE(of, linflex_dt_ids);
130 
131 #ifdef CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE
132 static struct uart_port *earlycon_port;
133 static bool linflex_earlycon_same_instance;
134 static DEFINE_SPINLOCK(init_lock);
135 static bool during_init;
136 
137 static struct {
138 	char *content;
139 	unsigned int len, cap;
140 } earlycon_buf;
141 #endif
142 
143 static void linflex_stop_tx(struct uart_port *port)
144 {
145 	unsigned long ier;
146 
147 	ier = readl(port->membase + LINIER);
148 	ier &= ~(LINFLEXD_LINIER_DTIE);
149 	writel(ier, port->membase + LINIER);
150 }
151 
152 static void linflex_stop_rx(struct uart_port *port)
153 {
154 	unsigned long ier;
155 
156 	ier = readl(port->membase + LINIER);
157 	writel(ier & ~LINFLEXD_LINIER_DRIE, port->membase + LINIER);
158 }
159 
160 static void linflex_put_char(struct uart_port *sport, unsigned char c)
161 {
162 	unsigned long status;
163 
164 	writeb(c, sport->membase + BDRL);
165 
166 	/* Waiting for data transmission completed. */
167 	while (((status = readl(sport->membase + UARTSR)) &
168 				LINFLEXD_UARTSR_DTFTFF) !=
169 				LINFLEXD_UARTSR_DTFTFF)
170 		;
171 
172 	writel(status | LINFLEXD_UARTSR_DTFTFF, sport->membase + UARTSR);
173 }
174 
175 static inline void linflex_transmit_buffer(struct uart_port *sport)
176 {
177 	struct circ_buf *xmit = &sport->state->xmit;
178 
179 	while (!uart_circ_empty(xmit)) {
180 		linflex_put_char(sport, xmit->buf[xmit->tail]);
181 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
182 		sport->icount.tx++;
183 	}
184 
185 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
186 		uart_write_wakeup(sport);
187 
188 	if (uart_circ_empty(xmit))
189 		linflex_stop_tx(sport);
190 }
191 
192 static void linflex_start_tx(struct uart_port *port)
193 {
194 	unsigned long ier;
195 
196 	linflex_transmit_buffer(port);
197 	ier = readl(port->membase + LINIER);
198 	writel(ier | LINFLEXD_LINIER_DTIE, port->membase + LINIER);
199 }
200 
201 static irqreturn_t linflex_txint(int irq, void *dev_id)
202 {
203 	struct uart_port *sport = dev_id;
204 	struct circ_buf *xmit = &sport->state->xmit;
205 	unsigned long flags;
206 
207 	spin_lock_irqsave(&sport->lock, flags);
208 
209 	if (sport->x_char) {
210 		linflex_put_char(sport, sport->x_char);
211 		goto out;
212 	}
213 
214 	if (uart_circ_empty(xmit) || uart_tx_stopped(sport)) {
215 		linflex_stop_tx(sport);
216 		goto out;
217 	}
218 
219 	linflex_transmit_buffer(sport);
220 out:
221 	spin_unlock_irqrestore(&sport->lock, flags);
222 	return IRQ_HANDLED;
223 }
224 
225 static irqreturn_t linflex_rxint(int irq, void *dev_id)
226 {
227 	struct uart_port *sport = dev_id;
228 	unsigned int flg;
229 	struct tty_port *port = &sport->state->port;
230 	unsigned long flags, status;
231 	unsigned char rx;
232 	bool brk;
233 
234 	spin_lock_irqsave(&sport->lock, flags);
235 
236 	status = readl(sport->membase + UARTSR);
237 	while (status & LINFLEXD_UARTSR_RMB) {
238 		rx = readb(sport->membase + BDRM);
239 		brk = false;
240 		flg = TTY_NORMAL;
241 		sport->icount.rx++;
242 
243 		if (status & (LINFLEXD_UARTSR_BOF | LINFLEXD_UARTSR_FEF |
244 				LINFLEXD_UARTSR_PE)) {
245 			if (status & LINFLEXD_UARTSR_BOF)
246 				sport->icount.overrun++;
247 			if (status & LINFLEXD_UARTSR_FEF) {
248 				if (!rx) {
249 					brk = true;
250 					sport->icount.brk++;
251 				} else
252 					sport->icount.frame++;
253 			}
254 			if (status & LINFLEXD_UARTSR_PE)
255 				sport->icount.parity++;
256 		}
257 
258 		writel(status, sport->membase + UARTSR);
259 		status = readl(sport->membase + UARTSR);
260 
261 		if (brk) {
262 			uart_handle_break(sport);
263 		} else {
264 			if (uart_handle_sysrq_char(sport, (unsigned char)rx))
265 				continue;
266 			tty_insert_flip_char(port, rx, flg);
267 		}
268 	}
269 
270 	spin_unlock_irqrestore(&sport->lock, flags);
271 
272 	tty_flip_buffer_push(port);
273 
274 	return IRQ_HANDLED;
275 }
276 
277 static irqreturn_t linflex_int(int irq, void *dev_id)
278 {
279 	struct uart_port *sport = dev_id;
280 	unsigned long status;
281 
282 	status = readl(sport->membase + UARTSR);
283 
284 	if (status & LINFLEXD_UARTSR_DRFRFE)
285 		linflex_rxint(irq, dev_id);
286 	if (status & LINFLEXD_UARTSR_DTFTFF)
287 		linflex_txint(irq, dev_id);
288 
289 	return IRQ_HANDLED;
290 }
291 
292 /* return TIOCSER_TEMT when transmitter is not busy */
293 static unsigned int linflex_tx_empty(struct uart_port *port)
294 {
295 	unsigned long status;
296 
297 	status = readl(port->membase + UARTSR) & LINFLEXD_UARTSR_DTFTFF;
298 
299 	return status ? TIOCSER_TEMT : 0;
300 }
301 
302 static unsigned int linflex_get_mctrl(struct uart_port *port)
303 {
304 	return 0;
305 }
306 
307 static void linflex_set_mctrl(struct uart_port *port, unsigned int mctrl)
308 {
309 }
310 
311 static void linflex_break_ctl(struct uart_port *port, int break_state)
312 {
313 }
314 
315 static void linflex_setup_watermark(struct uart_port *sport)
316 {
317 	unsigned long cr, ier, cr1;
318 
319 	/* Disable transmission/reception */
320 	ier = readl(sport->membase + LINIER);
321 	ier &= ~(LINFLEXD_LINIER_DRIE | LINFLEXD_LINIER_DTIE);
322 	writel(ier, sport->membase + LINIER);
323 
324 	cr = readl(sport->membase + UARTCR);
325 	cr &= ~(LINFLEXD_UARTCR_RXEN | LINFLEXD_UARTCR_TXEN);
326 	writel(cr, sport->membase + UARTCR);
327 
328 	/* Enter initialization mode by setting INIT bit */
329 
330 	/* set the Linflex in master mode and activate by-pass filter */
331 	cr1 = LINFLEXD_LINCR1_BF | LINFLEXD_LINCR1_MME
332 	      | LINFLEXD_LINCR1_INIT;
333 	writel(cr1, sport->membase + LINCR1);
334 
335 	/* wait for init mode entry */
336 	while ((readl(sport->membase + LINSR)
337 		& LINFLEXD_LINSR_LINS_MASK)
338 		!= LINFLEXD_LINSR_LINS_INITMODE)
339 		;
340 
341 	/*
342 	 *	UART = 0x1;		- Linflex working in UART mode
343 	 *	TXEN = 0x1;		- Enable transmission of data now
344 	 *	RXEn = 0x1;		- Receiver enabled
345 	 *	WL0 = 0x1;		- 8 bit data
346 	 *	PCE = 0x0;		- No parity
347 	 */
348 
349 	/* set UART bit to allow writing other bits */
350 	writel(LINFLEXD_UARTCR_UART, sport->membase + UARTCR);
351 
352 	cr = (LINFLEXD_UARTCR_RXEN | LINFLEXD_UARTCR_TXEN |
353 	      LINFLEXD_UARTCR_WL0 | LINFLEXD_UARTCR_UART);
354 
355 	writel(cr, sport->membase + UARTCR);
356 
357 	cr1 &= ~(LINFLEXD_LINCR1_INIT);
358 
359 	writel(cr1, sport->membase + LINCR1);
360 
361 	ier = readl(sport->membase + LINIER);
362 	ier |= LINFLEXD_LINIER_DRIE;
363 	ier |= LINFLEXD_LINIER_DTIE;
364 
365 	writel(ier, sport->membase + LINIER);
366 }
367 
368 static int linflex_startup(struct uart_port *port)
369 {
370 	int ret = 0;
371 	unsigned long flags;
372 
373 	spin_lock_irqsave(&port->lock, flags);
374 
375 	linflex_setup_watermark(port);
376 
377 	spin_unlock_irqrestore(&port->lock, flags);
378 
379 	ret = devm_request_irq(port->dev, port->irq, linflex_int, 0,
380 			       DRIVER_NAME, port);
381 
382 	return ret;
383 }
384 
385 static void linflex_shutdown(struct uart_port *port)
386 {
387 	unsigned long ier;
388 	unsigned long flags;
389 
390 	spin_lock_irqsave(&port->lock, flags);
391 
392 	/* disable interrupts */
393 	ier = readl(port->membase + LINIER);
394 	ier &= ~(LINFLEXD_LINIER_DRIE | LINFLEXD_LINIER_DTIE);
395 	writel(ier, port->membase + LINIER);
396 
397 	spin_unlock_irqrestore(&port->lock, flags);
398 
399 	devm_free_irq(port->dev, port->irq, port);
400 }
401 
402 static void
403 linflex_set_termios(struct uart_port *port, struct ktermios *termios,
404 		    struct ktermios *old)
405 {
406 	unsigned long flags;
407 	unsigned long cr, old_cr, cr1;
408 	unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;
409 
410 	cr = readl(port->membase + UARTCR);
411 	old_cr = cr;
412 
413 	/* Enter initialization mode by setting INIT bit */
414 	cr1 = readl(port->membase + LINCR1);
415 	cr1 |= LINFLEXD_LINCR1_INIT;
416 	writel(cr1, port->membase + LINCR1);
417 
418 	/* wait for init mode entry */
419 	while ((readl(port->membase + LINSR)
420 		& LINFLEXD_LINSR_LINS_MASK)
421 		!= LINFLEXD_LINSR_LINS_INITMODE)
422 		;
423 
424 	/*
425 	 * only support CS8 and CS7, and for CS7 must enable PE.
426 	 * supported mode:
427 	 *	- (7,e/o,1)
428 	 *	- (8,n,1)
429 	 *	- (8,e/o,1)
430 	 */
431 	/* enter the UART into configuration mode */
432 
433 	while ((termios->c_cflag & CSIZE) != CS8 &&
434 	       (termios->c_cflag & CSIZE) != CS7) {
435 		termios->c_cflag &= ~CSIZE;
436 		termios->c_cflag |= old_csize;
437 		old_csize = CS8;
438 	}
439 
440 	if ((termios->c_cflag & CSIZE) == CS7) {
441 		/* Word length: WL1WL0:00 */
442 		cr = old_cr & ~LINFLEXD_UARTCR_WL1 & ~LINFLEXD_UARTCR_WL0;
443 	}
444 
445 	if ((termios->c_cflag & CSIZE) == CS8) {
446 		/* Word length: WL1WL0:01 */
447 		cr = (old_cr | LINFLEXD_UARTCR_WL0) & ~LINFLEXD_UARTCR_WL1;
448 	}
449 
450 	if (termios->c_cflag & CMSPAR) {
451 		if ((termios->c_cflag & CSIZE) != CS8) {
452 			termios->c_cflag &= ~CSIZE;
453 			termios->c_cflag |= CS8;
454 		}
455 		/* has a space/sticky bit */
456 		cr |= LINFLEXD_UARTCR_WL0;
457 	}
458 
459 	if (termios->c_cflag & CSTOPB)
460 		termios->c_cflag &= ~CSTOPB;
461 
462 	/* parity must be enabled when CS7 to match 8-bits format */
463 	if ((termios->c_cflag & CSIZE) == CS7)
464 		termios->c_cflag |= PARENB;
465 
466 	if ((termios->c_cflag & PARENB)) {
467 		cr |= LINFLEXD_UARTCR_PCE;
468 		if (termios->c_cflag & PARODD)
469 			cr = (cr | LINFLEXD_UARTCR_PC0) &
470 			     (~LINFLEXD_UARTCR_PC1);
471 		else
472 			cr = cr & (~LINFLEXD_UARTCR_PC1 &
473 				   ~LINFLEXD_UARTCR_PC0);
474 	} else {
475 		cr &= ~LINFLEXD_UARTCR_PCE;
476 	}
477 
478 	spin_lock_irqsave(&port->lock, flags);
479 
480 	port->read_status_mask = 0;
481 
482 	if (termios->c_iflag & INPCK)
483 		port->read_status_mask |=	(LINFLEXD_UARTSR_FEF |
484 						 LINFLEXD_UARTSR_PE0 |
485 						 LINFLEXD_UARTSR_PE1 |
486 						 LINFLEXD_UARTSR_PE2 |
487 						 LINFLEXD_UARTSR_PE3);
488 	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
489 		port->read_status_mask |= LINFLEXD_UARTSR_FEF;
490 
491 	/* characters to ignore */
492 	port->ignore_status_mask = 0;
493 	if (termios->c_iflag & IGNPAR)
494 		port->ignore_status_mask |= LINFLEXD_UARTSR_PE;
495 	if (termios->c_iflag & IGNBRK) {
496 		port->ignore_status_mask |= LINFLEXD_UARTSR_PE;
497 		/*
498 		 * if we're ignoring parity and break indicators,
499 		 * ignore overruns too (for real raw support).
500 		 */
501 		if (termios->c_iflag & IGNPAR)
502 			port->ignore_status_mask |= LINFLEXD_UARTSR_BOF;
503 	}
504 
505 	writel(cr, port->membase + UARTCR);
506 
507 	cr1 &= ~(LINFLEXD_LINCR1_INIT);
508 
509 	writel(cr1, port->membase + LINCR1);
510 
511 	spin_unlock_irqrestore(&port->lock, flags);
512 }
513 
514 static const char *linflex_type(struct uart_port *port)
515 {
516 	return "FSL_LINFLEX";
517 }
518 
519 static void linflex_release_port(struct uart_port *port)
520 {
521 	/* nothing to do */
522 }
523 
524 static int linflex_request_port(struct uart_port *port)
525 {
526 	return 0;
527 }
528 
529 /* configure/auto-configure the port */
530 static void linflex_config_port(struct uart_port *port, int flags)
531 {
532 	if (flags & UART_CONFIG_TYPE)
533 		port->type = PORT_LINFLEXUART;
534 }
535 
536 static const struct uart_ops linflex_pops = {
537 	.tx_empty	= linflex_tx_empty,
538 	.set_mctrl	= linflex_set_mctrl,
539 	.get_mctrl	= linflex_get_mctrl,
540 	.stop_tx	= linflex_stop_tx,
541 	.start_tx	= linflex_start_tx,
542 	.stop_rx	= linflex_stop_rx,
543 	.break_ctl	= linflex_break_ctl,
544 	.startup	= linflex_startup,
545 	.shutdown	= linflex_shutdown,
546 	.set_termios	= linflex_set_termios,
547 	.type		= linflex_type,
548 	.request_port	= linflex_request_port,
549 	.release_port	= linflex_release_port,
550 	.config_port	= linflex_config_port,
551 };
552 
553 static struct uart_port *linflex_ports[UART_NR];
554 
555 #ifdef CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE
556 static void linflex_console_putchar(struct uart_port *port, unsigned char ch)
557 {
558 	unsigned long cr;
559 
560 	cr = readl(port->membase + UARTCR);
561 
562 	writeb(ch, port->membase + BDRL);
563 
564 	if (!(cr & LINFLEXD_UARTCR_TFBM))
565 		while ((readl(port->membase + UARTSR) &
566 					LINFLEXD_UARTSR_DTFTFF)
567 				!= LINFLEXD_UARTSR_DTFTFF)
568 			;
569 	else
570 		while (readl(port->membase + UARTSR) &
571 					LINFLEXD_UARTSR_DTFTFF)
572 			;
573 
574 	if (!(cr & LINFLEXD_UARTCR_TFBM)) {
575 		writel((readl(port->membase + UARTSR) |
576 					LINFLEXD_UARTSR_DTFTFF),
577 					port->membase + UARTSR);
578 	}
579 }
580 
581 static void linflex_earlycon_putchar(struct uart_port *port, unsigned char ch)
582 {
583 	unsigned long flags;
584 	char *ret;
585 
586 	if (!linflex_earlycon_same_instance) {
587 		linflex_console_putchar(port, ch);
588 		return;
589 	}
590 
591 	spin_lock_irqsave(&init_lock, flags);
592 	if (!during_init)
593 		goto outside_init;
594 
595 	if (earlycon_buf.len >= 1 << CONFIG_LOG_BUF_SHIFT)
596 		goto init_release;
597 
598 	if (!earlycon_buf.cap) {
599 		earlycon_buf.content = kmalloc(EARLYCON_BUFFER_INITIAL_CAP,
600 					       GFP_ATOMIC);
601 		earlycon_buf.cap = earlycon_buf.content ?
602 				   EARLYCON_BUFFER_INITIAL_CAP : 0;
603 	} else if (earlycon_buf.len == earlycon_buf.cap) {
604 		ret = krealloc(earlycon_buf.content, earlycon_buf.cap << 1,
605 			       GFP_ATOMIC);
606 		if (ret) {
607 			earlycon_buf.content = ret;
608 			earlycon_buf.cap <<= 1;
609 		}
610 	}
611 
612 	if (earlycon_buf.len < earlycon_buf.cap)
613 		earlycon_buf.content[earlycon_buf.len++] = ch;
614 
615 	goto init_release;
616 
617 outside_init:
618 	linflex_console_putchar(port, ch);
619 init_release:
620 	spin_unlock_irqrestore(&init_lock, flags);
621 }
622 
623 static void linflex_string_write(struct uart_port *sport, const char *s,
624 				 unsigned int count)
625 {
626 	unsigned long cr, ier = 0;
627 
628 	ier = readl(sport->membase + LINIER);
629 	linflex_stop_tx(sport);
630 
631 	cr = readl(sport->membase + UARTCR);
632 	cr |= (LINFLEXD_UARTCR_TXEN);
633 	writel(cr, sport->membase + UARTCR);
634 
635 	uart_console_write(sport, s, count, linflex_console_putchar);
636 
637 	writel(ier, sport->membase + LINIER);
638 }
639 
640 static void
641 linflex_console_write(struct console *co, const char *s, unsigned int count)
642 {
643 	struct uart_port *sport = linflex_ports[co->index];
644 	unsigned long flags;
645 	int locked = 1;
646 
647 	if (sport->sysrq)
648 		locked = 0;
649 	else if (oops_in_progress)
650 		locked = spin_trylock_irqsave(&sport->lock, flags);
651 	else
652 		spin_lock_irqsave(&sport->lock, flags);
653 
654 	linflex_string_write(sport, s, count);
655 
656 	if (locked)
657 		spin_unlock_irqrestore(&sport->lock, flags);
658 }
659 
660 /*
661  * if the port was already initialised (eg, by a boot loader),
662  * try to determine the current setup.
663  */
664 static void __init
665 linflex_console_get_options(struct uart_port *sport, int *parity, int *bits)
666 {
667 	unsigned long cr;
668 
669 	cr = readl(sport->membase + UARTCR);
670 	cr &= LINFLEXD_UARTCR_RXEN | LINFLEXD_UARTCR_TXEN;
671 
672 	if (!cr)
673 		return;
674 
675 	/* ok, the port was enabled */
676 
677 	*parity = 'n';
678 	if (cr & LINFLEXD_UARTCR_PCE) {
679 		if (cr & LINFLEXD_UARTCR_PC0)
680 			*parity = 'o';
681 		else
682 			*parity = 'e';
683 	}
684 
685 	if ((cr & LINFLEXD_UARTCR_WL0) && ((cr & LINFLEXD_UARTCR_WL1) == 0)) {
686 		if (cr & LINFLEXD_UARTCR_PCE)
687 			*bits = 9;
688 		else
689 			*bits = 8;
690 	}
691 }
692 
693 static int __init linflex_console_setup(struct console *co, char *options)
694 {
695 	struct uart_port *sport;
696 	int baud = 115200;
697 	int bits = 8;
698 	int parity = 'n';
699 	int flow = 'n';
700 	int ret;
701 	int i;
702 	unsigned long flags;
703 	/*
704 	 * check whether an invalid uart number has been specified, and
705 	 * if so, search for the first available port that does have
706 	 * console support.
707 	 */
708 	if (co->index == -1 || co->index >= ARRAY_SIZE(linflex_ports))
709 		co->index = 0;
710 
711 	sport = linflex_ports[co->index];
712 	if (!sport)
713 		return -ENODEV;
714 
715 	if (options)
716 		uart_parse_options(options, &baud, &parity, &bits, &flow);
717 	else
718 		linflex_console_get_options(sport, &parity, &bits);
719 
720 	if (earlycon_port && sport->mapbase == earlycon_port->mapbase) {
721 		linflex_earlycon_same_instance = true;
722 
723 		spin_lock_irqsave(&init_lock, flags);
724 		during_init = true;
725 		spin_unlock_irqrestore(&init_lock, flags);
726 
727 		/* Workaround for character loss or output of many invalid
728 		 * characters, when INIT mode is entered shortly after a
729 		 * character has just been printed.
730 		 */
731 		udelay(PREINIT_DELAY);
732 	}
733 
734 	linflex_setup_watermark(sport);
735 
736 	ret = uart_set_options(sport, co, baud, parity, bits, flow);
737 
738 	if (!linflex_earlycon_same_instance)
739 		goto done;
740 
741 	spin_lock_irqsave(&init_lock, flags);
742 
743 	/* Emptying buffer */
744 	if (earlycon_buf.len) {
745 		for (i = 0; i < earlycon_buf.len; i++)
746 			linflex_console_putchar(earlycon_port,
747 				earlycon_buf.content[i]);
748 
749 		kfree(earlycon_buf.content);
750 		earlycon_buf.len = 0;
751 	}
752 
753 	during_init = false;
754 	spin_unlock_irqrestore(&init_lock, flags);
755 
756 done:
757 	return ret;
758 }
759 
760 static struct uart_driver linflex_reg;
761 static struct console linflex_console = {
762 	.name		= DEV_NAME,
763 	.write		= linflex_console_write,
764 	.device		= uart_console_device,
765 	.setup		= linflex_console_setup,
766 	.flags		= CON_PRINTBUFFER,
767 	.index		= -1,
768 	.data		= &linflex_reg,
769 };
770 
771 static void linflex_earlycon_write(struct console *con, const char *s,
772 				   unsigned int n)
773 {
774 	struct earlycon_device *dev = con->data;
775 
776 	uart_console_write(&dev->port, s, n, linflex_earlycon_putchar);
777 }
778 
779 static int __init linflex_early_console_setup(struct earlycon_device *device,
780 					      const char *options)
781 {
782 	if (!device->port.membase)
783 		return -ENODEV;
784 
785 	device->con->write = linflex_earlycon_write;
786 	earlycon_port = &device->port;
787 
788 	return 0;
789 }
790 
791 OF_EARLYCON_DECLARE(linflex, "fsl,s32v234-linflexuart",
792 		    linflex_early_console_setup);
793 
794 #define LINFLEX_CONSOLE	(&linflex_console)
795 #else
796 #define LINFLEX_CONSOLE	NULL
797 #endif
798 
799 static struct uart_driver linflex_reg = {
800 	.owner		= THIS_MODULE,
801 	.driver_name	= DRIVER_NAME,
802 	.dev_name	= DEV_NAME,
803 	.nr		= ARRAY_SIZE(linflex_ports),
804 	.cons		= LINFLEX_CONSOLE,
805 };
806 
807 static int linflex_probe(struct platform_device *pdev)
808 {
809 	struct device_node *np = pdev->dev.of_node;
810 	struct uart_port *sport;
811 	struct resource *res;
812 	int ret;
813 
814 	sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL);
815 	if (!sport)
816 		return -ENOMEM;
817 
818 	ret = of_alias_get_id(np, "serial");
819 	if (ret < 0) {
820 		dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
821 		return ret;
822 	}
823 	if (ret >= UART_NR) {
824 		dev_err(&pdev->dev, "driver limited to %d serial ports\n",
825 			UART_NR);
826 		return -ENOMEM;
827 	}
828 
829 	sport->line = ret;
830 
831 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
832 	if (!res)
833 		return -ENODEV;
834 
835 	sport->mapbase = res->start;
836 	sport->membase = devm_ioremap_resource(&pdev->dev, res);
837 	if (IS_ERR(sport->membase))
838 		return PTR_ERR(sport->membase);
839 
840 	sport->dev = &pdev->dev;
841 	sport->type = PORT_LINFLEXUART;
842 	sport->iotype = UPIO_MEM;
843 	sport->irq = platform_get_irq(pdev, 0);
844 	sport->ops = &linflex_pops;
845 	sport->flags = UPF_BOOT_AUTOCONF;
846 	sport->has_sysrq = IS_ENABLED(CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE);
847 
848 	linflex_ports[sport->line] = sport;
849 
850 	platform_set_drvdata(pdev, sport);
851 
852 	return uart_add_one_port(&linflex_reg, sport);
853 }
854 
855 static int linflex_remove(struct platform_device *pdev)
856 {
857 	struct uart_port *sport = platform_get_drvdata(pdev);
858 
859 	uart_remove_one_port(&linflex_reg, sport);
860 
861 	return 0;
862 }
863 
864 #ifdef CONFIG_PM_SLEEP
865 static int linflex_suspend(struct device *dev)
866 {
867 	struct uart_port *sport = dev_get_drvdata(dev);
868 
869 	uart_suspend_port(&linflex_reg, sport);
870 
871 	return 0;
872 }
873 
874 static int linflex_resume(struct device *dev)
875 {
876 	struct uart_port *sport = dev_get_drvdata(dev);
877 
878 	uart_resume_port(&linflex_reg, sport);
879 
880 	return 0;
881 }
882 #endif
883 
884 static SIMPLE_DEV_PM_OPS(linflex_pm_ops, linflex_suspend, linflex_resume);
885 
886 static struct platform_driver linflex_driver = {
887 	.probe		= linflex_probe,
888 	.remove		= linflex_remove,
889 	.driver		= {
890 		.name	= DRIVER_NAME,
891 		.of_match_table	= linflex_dt_ids,
892 		.pm	= &linflex_pm_ops,
893 	},
894 };
895 
896 static int __init linflex_serial_init(void)
897 {
898 	int ret;
899 
900 	ret = uart_register_driver(&linflex_reg);
901 	if (ret)
902 		return ret;
903 
904 	ret = platform_driver_register(&linflex_driver);
905 	if (ret)
906 		uart_unregister_driver(&linflex_reg);
907 
908 	return ret;
909 }
910 
911 static void __exit linflex_serial_exit(void)
912 {
913 	platform_driver_unregister(&linflex_driver);
914 	uart_unregister_driver(&linflex_reg);
915 }
916 
917 module_init(linflex_serial_init);
918 module_exit(linflex_serial_exit);
919 
920 MODULE_DESCRIPTION("Freescale LINFlexD serial port driver");
921 MODULE_LICENSE("GPL v2");
922