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/platform_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 
linflex_stop_tx(struct uart_port * port)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 
linflex_stop_rx(struct uart_port * port)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 
linflex_put_char(struct uart_port * sport,unsigned char c)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 
linflex_transmit_buffer(struct uart_port * sport)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 		uart_xmit_advance(sport, 1);
182 	}
183 
184 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
185 		uart_write_wakeup(sport);
186 
187 	if (uart_circ_empty(xmit))
188 		linflex_stop_tx(sport);
189 }
190 
linflex_start_tx(struct uart_port * port)191 static void linflex_start_tx(struct uart_port *port)
192 {
193 	unsigned long ier;
194 
195 	linflex_transmit_buffer(port);
196 	ier = readl(port->membase + LINIER);
197 	writel(ier | LINFLEXD_LINIER_DTIE, port->membase + LINIER);
198 }
199 
linflex_txint(int irq,void * dev_id)200 static irqreturn_t linflex_txint(int irq, void *dev_id)
201 {
202 	struct uart_port *sport = dev_id;
203 	struct circ_buf *xmit = &sport->state->xmit;
204 	unsigned long flags;
205 
206 	spin_lock_irqsave(&sport->lock, flags);
207 
208 	if (sport->x_char) {
209 		linflex_put_char(sport, sport->x_char);
210 		goto out;
211 	}
212 
213 	if (uart_circ_empty(xmit) || uart_tx_stopped(sport)) {
214 		linflex_stop_tx(sport);
215 		goto out;
216 	}
217 
218 	linflex_transmit_buffer(sport);
219 out:
220 	spin_unlock_irqrestore(&sport->lock, flags);
221 	return IRQ_HANDLED;
222 }
223 
linflex_rxint(int irq,void * dev_id)224 static irqreturn_t linflex_rxint(int irq, void *dev_id)
225 {
226 	struct uart_port *sport = dev_id;
227 	unsigned int flg;
228 	struct tty_port *port = &sport->state->port;
229 	unsigned long flags, status;
230 	unsigned char rx;
231 	bool brk;
232 
233 	spin_lock_irqsave(&sport->lock, flags);
234 
235 	status = readl(sport->membase + UARTSR);
236 	while (status & LINFLEXD_UARTSR_RMB) {
237 		rx = readb(sport->membase + BDRM);
238 		brk = false;
239 		flg = TTY_NORMAL;
240 		sport->icount.rx++;
241 
242 		if (status & (LINFLEXD_UARTSR_BOF | LINFLEXD_UARTSR_FEF |
243 				LINFLEXD_UARTSR_PE)) {
244 			if (status & LINFLEXD_UARTSR_BOF)
245 				sport->icount.overrun++;
246 			if (status & LINFLEXD_UARTSR_FEF) {
247 				if (!rx) {
248 					brk = true;
249 					sport->icount.brk++;
250 				} else
251 					sport->icount.frame++;
252 			}
253 			if (status & LINFLEXD_UARTSR_PE)
254 				sport->icount.parity++;
255 		}
256 
257 		writel(status, sport->membase + UARTSR);
258 		status = readl(sport->membase + UARTSR);
259 
260 		if (brk) {
261 			uart_handle_break(sport);
262 		} else {
263 			if (uart_handle_sysrq_char(sport, (unsigned char)rx))
264 				continue;
265 			tty_insert_flip_char(port, rx, flg);
266 		}
267 	}
268 
269 	spin_unlock_irqrestore(&sport->lock, flags);
270 
271 	tty_flip_buffer_push(port);
272 
273 	return IRQ_HANDLED;
274 }
275 
linflex_int(int irq,void * dev_id)276 static irqreturn_t linflex_int(int irq, void *dev_id)
277 {
278 	struct uart_port *sport = dev_id;
279 	unsigned long status;
280 
281 	status = readl(sport->membase + UARTSR);
282 
283 	if (status & LINFLEXD_UARTSR_DRFRFE)
284 		linflex_rxint(irq, dev_id);
285 	if (status & LINFLEXD_UARTSR_DTFTFF)
286 		linflex_txint(irq, dev_id);
287 
288 	return IRQ_HANDLED;
289 }
290 
291 /* return TIOCSER_TEMT when transmitter is not busy */
linflex_tx_empty(struct uart_port * port)292 static unsigned int linflex_tx_empty(struct uart_port *port)
293 {
294 	unsigned long status;
295 
296 	status = readl(port->membase + UARTSR) & LINFLEXD_UARTSR_DTFTFF;
297 
298 	return status ? TIOCSER_TEMT : 0;
299 }
300 
linflex_get_mctrl(struct uart_port * port)301 static unsigned int linflex_get_mctrl(struct uart_port *port)
302 {
303 	return 0;
304 }
305 
linflex_set_mctrl(struct uart_port * port,unsigned int mctrl)306 static void linflex_set_mctrl(struct uart_port *port, unsigned int mctrl)
307 {
308 }
309 
linflex_break_ctl(struct uart_port * port,int break_state)310 static void linflex_break_ctl(struct uart_port *port, int break_state)
311 {
312 }
313 
linflex_setup_watermark(struct uart_port * sport)314 static void linflex_setup_watermark(struct uart_port *sport)
315 {
316 	unsigned long cr, ier, cr1;
317 
318 	/* Disable transmission/reception */
319 	ier = readl(sport->membase + LINIER);
320 	ier &= ~(LINFLEXD_LINIER_DRIE | LINFLEXD_LINIER_DTIE);
321 	writel(ier, sport->membase + LINIER);
322 
323 	cr = readl(sport->membase + UARTCR);
324 	cr &= ~(LINFLEXD_UARTCR_RXEN | LINFLEXD_UARTCR_TXEN);
325 	writel(cr, sport->membase + UARTCR);
326 
327 	/* Enter initialization mode by setting INIT bit */
328 
329 	/* set the Linflex in master mode and activate by-pass filter */
330 	cr1 = LINFLEXD_LINCR1_BF | LINFLEXD_LINCR1_MME
331 	      | LINFLEXD_LINCR1_INIT;
332 	writel(cr1, sport->membase + LINCR1);
333 
334 	/* wait for init mode entry */
335 	while ((readl(sport->membase + LINSR)
336 		& LINFLEXD_LINSR_LINS_MASK)
337 		!= LINFLEXD_LINSR_LINS_INITMODE)
338 		;
339 
340 	/*
341 	 *	UART = 0x1;		- Linflex working in UART mode
342 	 *	TXEN = 0x1;		- Enable transmission of data now
343 	 *	RXEn = 0x1;		- Receiver enabled
344 	 *	WL0 = 0x1;		- 8 bit data
345 	 *	PCE = 0x0;		- No parity
346 	 */
347 
348 	/* set UART bit to allow writing other bits */
349 	writel(LINFLEXD_UARTCR_UART, sport->membase + UARTCR);
350 
351 	cr = (LINFLEXD_UARTCR_RXEN | LINFLEXD_UARTCR_TXEN |
352 	      LINFLEXD_UARTCR_WL0 | LINFLEXD_UARTCR_UART);
353 
354 	writel(cr, sport->membase + UARTCR);
355 
356 	cr1 &= ~(LINFLEXD_LINCR1_INIT);
357 
358 	writel(cr1, sport->membase + LINCR1);
359 
360 	ier = readl(sport->membase + LINIER);
361 	ier |= LINFLEXD_LINIER_DRIE;
362 	ier |= LINFLEXD_LINIER_DTIE;
363 
364 	writel(ier, sport->membase + LINIER);
365 }
366 
linflex_startup(struct uart_port * port)367 static int linflex_startup(struct uart_port *port)
368 {
369 	int ret = 0;
370 	unsigned long flags;
371 
372 	spin_lock_irqsave(&port->lock, flags);
373 
374 	linflex_setup_watermark(port);
375 
376 	spin_unlock_irqrestore(&port->lock, flags);
377 
378 	ret = devm_request_irq(port->dev, port->irq, linflex_int, 0,
379 			       DRIVER_NAME, port);
380 
381 	return ret;
382 }
383 
linflex_shutdown(struct uart_port * port)384 static void linflex_shutdown(struct uart_port *port)
385 {
386 	unsigned long ier;
387 	unsigned long flags;
388 
389 	spin_lock_irqsave(&port->lock, flags);
390 
391 	/* disable interrupts */
392 	ier = readl(port->membase + LINIER);
393 	ier &= ~(LINFLEXD_LINIER_DRIE | LINFLEXD_LINIER_DTIE);
394 	writel(ier, port->membase + LINIER);
395 
396 	spin_unlock_irqrestore(&port->lock, flags);
397 
398 	devm_free_irq(port->dev, port->irq, port);
399 }
400 
401 static void
linflex_set_termios(struct uart_port * port,struct ktermios * termios,const struct ktermios * old)402 linflex_set_termios(struct uart_port *port, struct ktermios *termios,
403 		    const struct ktermios *old)
404 {
405 	unsigned long flags;
406 	unsigned long cr, old_cr, cr1;
407 	unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;
408 
409 	cr = readl(port->membase + UARTCR);
410 	old_cr = cr;
411 
412 	/* Enter initialization mode by setting INIT bit */
413 	cr1 = readl(port->membase + LINCR1);
414 	cr1 |= LINFLEXD_LINCR1_INIT;
415 	writel(cr1, port->membase + LINCR1);
416 
417 	/* wait for init mode entry */
418 	while ((readl(port->membase + LINSR)
419 		& LINFLEXD_LINSR_LINS_MASK)
420 		!= LINFLEXD_LINSR_LINS_INITMODE)
421 		;
422 
423 	/*
424 	 * only support CS8 and CS7, and for CS7 must enable PE.
425 	 * supported mode:
426 	 *	- (7,e/o,1)
427 	 *	- (8,n,1)
428 	 *	- (8,e/o,1)
429 	 */
430 	/* enter the UART into configuration mode */
431 
432 	while ((termios->c_cflag & CSIZE) != CS8 &&
433 	       (termios->c_cflag & CSIZE) != CS7) {
434 		termios->c_cflag &= ~CSIZE;
435 		termios->c_cflag |= old_csize;
436 		old_csize = CS8;
437 	}
438 
439 	if ((termios->c_cflag & CSIZE) == CS7) {
440 		/* Word length: WL1WL0:00 */
441 		cr = old_cr & ~LINFLEXD_UARTCR_WL1 & ~LINFLEXD_UARTCR_WL0;
442 	}
443 
444 	if ((termios->c_cflag & CSIZE) == CS8) {
445 		/* Word length: WL1WL0:01 */
446 		cr = (old_cr | LINFLEXD_UARTCR_WL0) & ~LINFLEXD_UARTCR_WL1;
447 	}
448 
449 	if (termios->c_cflag & CMSPAR) {
450 		if ((termios->c_cflag & CSIZE) != CS8) {
451 			termios->c_cflag &= ~CSIZE;
452 			termios->c_cflag |= CS8;
453 		}
454 		/* has a space/sticky bit */
455 		cr |= LINFLEXD_UARTCR_WL0;
456 	}
457 
458 	if (termios->c_cflag & CSTOPB)
459 		termios->c_cflag &= ~CSTOPB;
460 
461 	/* parity must be enabled when CS7 to match 8-bits format */
462 	if ((termios->c_cflag & CSIZE) == CS7)
463 		termios->c_cflag |= PARENB;
464 
465 	if ((termios->c_cflag & PARENB)) {
466 		cr |= LINFLEXD_UARTCR_PCE;
467 		if (termios->c_cflag & PARODD)
468 			cr = (cr | LINFLEXD_UARTCR_PC0) &
469 			     (~LINFLEXD_UARTCR_PC1);
470 		else
471 			cr = cr & (~LINFLEXD_UARTCR_PC1 &
472 				   ~LINFLEXD_UARTCR_PC0);
473 	} else {
474 		cr &= ~LINFLEXD_UARTCR_PCE;
475 	}
476 
477 	spin_lock_irqsave(&port->lock, flags);
478 
479 	port->read_status_mask = 0;
480 
481 	if (termios->c_iflag & INPCK)
482 		port->read_status_mask |=	(LINFLEXD_UARTSR_FEF |
483 						 LINFLEXD_UARTSR_PE0 |
484 						 LINFLEXD_UARTSR_PE1 |
485 						 LINFLEXD_UARTSR_PE2 |
486 						 LINFLEXD_UARTSR_PE3);
487 	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
488 		port->read_status_mask |= LINFLEXD_UARTSR_FEF;
489 
490 	/* characters to ignore */
491 	port->ignore_status_mask = 0;
492 	if (termios->c_iflag & IGNPAR)
493 		port->ignore_status_mask |= LINFLEXD_UARTSR_PE;
494 	if (termios->c_iflag & IGNBRK) {
495 		port->ignore_status_mask |= LINFLEXD_UARTSR_PE;
496 		/*
497 		 * if we're ignoring parity and break indicators,
498 		 * ignore overruns too (for real raw support).
499 		 */
500 		if (termios->c_iflag & IGNPAR)
501 			port->ignore_status_mask |= LINFLEXD_UARTSR_BOF;
502 	}
503 
504 	writel(cr, port->membase + UARTCR);
505 
506 	cr1 &= ~(LINFLEXD_LINCR1_INIT);
507 
508 	writel(cr1, port->membase + LINCR1);
509 
510 	spin_unlock_irqrestore(&port->lock, flags);
511 }
512 
linflex_type(struct uart_port * port)513 static const char *linflex_type(struct uart_port *port)
514 {
515 	return "FSL_LINFLEX";
516 }
517 
linflex_release_port(struct uart_port * port)518 static void linflex_release_port(struct uart_port *port)
519 {
520 	/* nothing to do */
521 }
522 
linflex_request_port(struct uart_port * port)523 static int linflex_request_port(struct uart_port *port)
524 {
525 	return 0;
526 }
527 
528 /* configure/auto-configure the port */
linflex_config_port(struct uart_port * port,int flags)529 static void linflex_config_port(struct uart_port *port, int flags)
530 {
531 	if (flags & UART_CONFIG_TYPE)
532 		port->type = PORT_LINFLEXUART;
533 }
534 
535 static const struct uart_ops linflex_pops = {
536 	.tx_empty	= linflex_tx_empty,
537 	.set_mctrl	= linflex_set_mctrl,
538 	.get_mctrl	= linflex_get_mctrl,
539 	.stop_tx	= linflex_stop_tx,
540 	.start_tx	= linflex_start_tx,
541 	.stop_rx	= linflex_stop_rx,
542 	.break_ctl	= linflex_break_ctl,
543 	.startup	= linflex_startup,
544 	.shutdown	= linflex_shutdown,
545 	.set_termios	= linflex_set_termios,
546 	.type		= linflex_type,
547 	.request_port	= linflex_request_port,
548 	.release_port	= linflex_release_port,
549 	.config_port	= linflex_config_port,
550 };
551 
552 static struct uart_port *linflex_ports[UART_NR];
553 
554 #ifdef CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE
linflex_console_putchar(struct uart_port * port,unsigned char ch)555 static void linflex_console_putchar(struct uart_port *port, unsigned char ch)
556 {
557 	unsigned long cr;
558 
559 	cr = readl(port->membase + UARTCR);
560 
561 	writeb(ch, port->membase + BDRL);
562 
563 	if (!(cr & LINFLEXD_UARTCR_TFBM))
564 		while ((readl(port->membase + UARTSR) &
565 					LINFLEXD_UARTSR_DTFTFF)
566 				!= LINFLEXD_UARTSR_DTFTFF)
567 			;
568 	else
569 		while (readl(port->membase + UARTSR) &
570 					LINFLEXD_UARTSR_DTFTFF)
571 			;
572 
573 	if (!(cr & LINFLEXD_UARTCR_TFBM)) {
574 		writel((readl(port->membase + UARTSR) |
575 					LINFLEXD_UARTSR_DTFTFF),
576 					port->membase + UARTSR);
577 	}
578 }
579 
linflex_earlycon_putchar(struct uart_port * port,unsigned char ch)580 static void linflex_earlycon_putchar(struct uart_port *port, unsigned char ch)
581 {
582 	unsigned long flags;
583 	char *ret;
584 
585 	if (!linflex_earlycon_same_instance) {
586 		linflex_console_putchar(port, ch);
587 		return;
588 	}
589 
590 	spin_lock_irqsave(&init_lock, flags);
591 	if (!during_init)
592 		goto outside_init;
593 
594 	if (earlycon_buf.len >= 1 << CONFIG_LOG_BUF_SHIFT)
595 		goto init_release;
596 
597 	if (!earlycon_buf.cap) {
598 		earlycon_buf.content = kmalloc(EARLYCON_BUFFER_INITIAL_CAP,
599 					       GFP_ATOMIC);
600 		earlycon_buf.cap = earlycon_buf.content ?
601 				   EARLYCON_BUFFER_INITIAL_CAP : 0;
602 	} else if (earlycon_buf.len == earlycon_buf.cap) {
603 		ret = krealloc(earlycon_buf.content, earlycon_buf.cap << 1,
604 			       GFP_ATOMIC);
605 		if (ret) {
606 			earlycon_buf.content = ret;
607 			earlycon_buf.cap <<= 1;
608 		}
609 	}
610 
611 	if (earlycon_buf.len < earlycon_buf.cap)
612 		earlycon_buf.content[earlycon_buf.len++] = ch;
613 
614 	goto init_release;
615 
616 outside_init:
617 	linflex_console_putchar(port, ch);
618 init_release:
619 	spin_unlock_irqrestore(&init_lock, flags);
620 }
621 
linflex_string_write(struct uart_port * sport,const char * s,unsigned int count)622 static void linflex_string_write(struct uart_port *sport, const char *s,
623 				 unsigned int count)
624 {
625 	unsigned long cr, ier = 0;
626 
627 	ier = readl(sport->membase + LINIER);
628 	linflex_stop_tx(sport);
629 
630 	cr = readl(sport->membase + UARTCR);
631 	cr |= (LINFLEXD_UARTCR_TXEN);
632 	writel(cr, sport->membase + UARTCR);
633 
634 	uart_console_write(sport, s, count, linflex_console_putchar);
635 
636 	writel(ier, sport->membase + LINIER);
637 }
638 
639 static void
linflex_console_write(struct console * co,const char * s,unsigned int count)640 linflex_console_write(struct console *co, const char *s, unsigned int count)
641 {
642 	struct uart_port *sport = linflex_ports[co->index];
643 	unsigned long flags;
644 	int locked = 1;
645 
646 	if (sport->sysrq)
647 		locked = 0;
648 	else if (oops_in_progress)
649 		locked = spin_trylock_irqsave(&sport->lock, flags);
650 	else
651 		spin_lock_irqsave(&sport->lock, flags);
652 
653 	linflex_string_write(sport, s, count);
654 
655 	if (locked)
656 		spin_unlock_irqrestore(&sport->lock, flags);
657 }
658 
659 /*
660  * if the port was already initialised (eg, by a boot loader),
661  * try to determine the current setup.
662  */
663 static void __init
linflex_console_get_options(struct uart_port * sport,int * parity,int * bits)664 linflex_console_get_options(struct uart_port *sport, int *parity, int *bits)
665 {
666 	unsigned long cr;
667 
668 	cr = readl(sport->membase + UARTCR);
669 	cr &= LINFLEXD_UARTCR_RXEN | LINFLEXD_UARTCR_TXEN;
670 
671 	if (!cr)
672 		return;
673 
674 	/* ok, the port was enabled */
675 
676 	*parity = 'n';
677 	if (cr & LINFLEXD_UARTCR_PCE) {
678 		if (cr & LINFLEXD_UARTCR_PC0)
679 			*parity = 'o';
680 		else
681 			*parity = 'e';
682 	}
683 
684 	if ((cr & LINFLEXD_UARTCR_WL0) && ((cr & LINFLEXD_UARTCR_WL1) == 0)) {
685 		if (cr & LINFLEXD_UARTCR_PCE)
686 			*bits = 9;
687 		else
688 			*bits = 8;
689 	}
690 }
691 
linflex_console_setup(struct console * co,char * options)692 static int __init linflex_console_setup(struct console *co, char *options)
693 {
694 	struct uart_port *sport;
695 	int baud = 115200;
696 	int bits = 8;
697 	int parity = 'n';
698 	int flow = 'n';
699 	int ret;
700 	int i;
701 	unsigned long flags;
702 	/*
703 	 * check whether an invalid uart number has been specified, and
704 	 * if so, search for the first available port that does have
705 	 * console support.
706 	 */
707 	if (co->index == -1 || co->index >= ARRAY_SIZE(linflex_ports))
708 		co->index = 0;
709 
710 	sport = linflex_ports[co->index];
711 	if (!sport)
712 		return -ENODEV;
713 
714 	if (options)
715 		uart_parse_options(options, &baud, &parity, &bits, &flow);
716 	else
717 		linflex_console_get_options(sport, &parity, &bits);
718 
719 	if (earlycon_port && sport->mapbase == earlycon_port->mapbase) {
720 		linflex_earlycon_same_instance = true;
721 
722 		spin_lock_irqsave(&init_lock, flags);
723 		during_init = true;
724 		spin_unlock_irqrestore(&init_lock, flags);
725 
726 		/* Workaround for character loss or output of many invalid
727 		 * characters, when INIT mode is entered shortly after a
728 		 * character has just been printed.
729 		 */
730 		udelay(PREINIT_DELAY);
731 	}
732 
733 	linflex_setup_watermark(sport);
734 
735 	ret = uart_set_options(sport, co, baud, parity, bits, flow);
736 
737 	if (!linflex_earlycon_same_instance)
738 		goto done;
739 
740 	spin_lock_irqsave(&init_lock, flags);
741 
742 	/* Emptying buffer */
743 	if (earlycon_buf.len) {
744 		for (i = 0; i < earlycon_buf.len; i++)
745 			linflex_console_putchar(earlycon_port,
746 				earlycon_buf.content[i]);
747 
748 		kfree(earlycon_buf.content);
749 		earlycon_buf.len = 0;
750 	}
751 
752 	during_init = false;
753 	spin_unlock_irqrestore(&init_lock, flags);
754 
755 done:
756 	return ret;
757 }
758 
759 static struct uart_driver linflex_reg;
760 static struct console linflex_console = {
761 	.name		= DEV_NAME,
762 	.write		= linflex_console_write,
763 	.device		= uart_console_device,
764 	.setup		= linflex_console_setup,
765 	.flags		= CON_PRINTBUFFER,
766 	.index		= -1,
767 	.data		= &linflex_reg,
768 };
769 
linflex_earlycon_write(struct console * con,const char * s,unsigned int n)770 static void linflex_earlycon_write(struct console *con, const char *s,
771 				   unsigned int n)
772 {
773 	struct earlycon_device *dev = con->data;
774 
775 	uart_console_write(&dev->port, s, n, linflex_earlycon_putchar);
776 }
777 
linflex_early_console_setup(struct earlycon_device * device,const char * options)778 static int __init linflex_early_console_setup(struct earlycon_device *device,
779 					      const char *options)
780 {
781 	if (!device->port.membase)
782 		return -ENODEV;
783 
784 	device->con->write = linflex_earlycon_write;
785 	earlycon_port = &device->port;
786 
787 	return 0;
788 }
789 
790 OF_EARLYCON_DECLARE(linflex, "fsl,s32v234-linflexuart",
791 		    linflex_early_console_setup);
792 
793 #define LINFLEX_CONSOLE	(&linflex_console)
794 #else
795 #define LINFLEX_CONSOLE	NULL
796 #endif
797 
798 static struct uart_driver linflex_reg = {
799 	.owner		= THIS_MODULE,
800 	.driver_name	= DRIVER_NAME,
801 	.dev_name	= DEV_NAME,
802 	.nr		= ARRAY_SIZE(linflex_ports),
803 	.cons		= LINFLEX_CONSOLE,
804 };
805 
linflex_probe(struct platform_device * pdev)806 static int linflex_probe(struct platform_device *pdev)
807 {
808 	struct device_node *np = pdev->dev.of_node;
809 	struct uart_port *sport;
810 	struct resource *res;
811 	int ret;
812 
813 	sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL);
814 	if (!sport)
815 		return -ENOMEM;
816 
817 	ret = of_alias_get_id(np, "serial");
818 	if (ret < 0) {
819 		dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
820 		return ret;
821 	}
822 	if (ret >= UART_NR) {
823 		dev_err(&pdev->dev, "driver limited to %d serial ports\n",
824 			UART_NR);
825 		return -ENOMEM;
826 	}
827 
828 	sport->line = ret;
829 
830 	sport->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
831 	if (IS_ERR(sport->membase))
832 		return PTR_ERR(sport->membase);
833 	sport->mapbase = res->start;
834 
835 	sport->dev = &pdev->dev;
836 	sport->type = PORT_LINFLEXUART;
837 	sport->iotype = UPIO_MEM;
838 	sport->irq = platform_get_irq(pdev, 0);
839 	sport->ops = &linflex_pops;
840 	sport->flags = UPF_BOOT_AUTOCONF;
841 	sport->has_sysrq = IS_ENABLED(CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE);
842 
843 	linflex_ports[sport->line] = sport;
844 
845 	platform_set_drvdata(pdev, sport);
846 
847 	return uart_add_one_port(&linflex_reg, sport);
848 }
849 
linflex_remove(struct platform_device * pdev)850 static int linflex_remove(struct platform_device *pdev)
851 {
852 	struct uart_port *sport = platform_get_drvdata(pdev);
853 
854 	uart_remove_one_port(&linflex_reg, sport);
855 
856 	return 0;
857 }
858 
859 #ifdef CONFIG_PM_SLEEP
linflex_suspend(struct device * dev)860 static int linflex_suspend(struct device *dev)
861 {
862 	struct uart_port *sport = dev_get_drvdata(dev);
863 
864 	uart_suspend_port(&linflex_reg, sport);
865 
866 	return 0;
867 }
868 
linflex_resume(struct device * dev)869 static int linflex_resume(struct device *dev)
870 {
871 	struct uart_port *sport = dev_get_drvdata(dev);
872 
873 	uart_resume_port(&linflex_reg, sport);
874 
875 	return 0;
876 }
877 #endif
878 
879 static SIMPLE_DEV_PM_OPS(linflex_pm_ops, linflex_suspend, linflex_resume);
880 
881 static struct platform_driver linflex_driver = {
882 	.probe		= linflex_probe,
883 	.remove		= linflex_remove,
884 	.driver		= {
885 		.name	= DRIVER_NAME,
886 		.of_match_table	= linflex_dt_ids,
887 		.pm	= &linflex_pm_ops,
888 	},
889 };
890 
linflex_serial_init(void)891 static int __init linflex_serial_init(void)
892 {
893 	int ret;
894 
895 	ret = uart_register_driver(&linflex_reg);
896 	if (ret)
897 		return ret;
898 
899 	ret = platform_driver_register(&linflex_driver);
900 	if (ret)
901 		uart_unregister_driver(&linflex_reg);
902 
903 	return ret;
904 }
905 
linflex_serial_exit(void)906 static void __exit linflex_serial_exit(void)
907 {
908 	platform_driver_unregister(&linflex_driver);
909 	uart_unregister_driver(&linflex_reg);
910 }
911 
912 module_init(linflex_serial_init);
913 module_exit(linflex_serial_exit);
914 
915 MODULE_DESCRIPTION("Freescale LINFlexD serial port driver");
916 MODULE_LICENSE("GPL v2");
917