xref: /linux/drivers/tty/serial/mcf.c (revision e6a901a00822659181c93c86d8bbc2a17779fddc) 
1 // SPDX-License-Identifier: GPL-2.0+
2 /****************************************************************************/
3 
4 /*
5  *	mcf.c -- Freescale ColdFire UART driver
6  *
7  *	(C) Copyright 2003-2007, Greg Ungerer <gerg@uclinux.org>
8  */
9 
10 /****************************************************************************/
11 
12 #include <linux/kernel.h>
13 #include <linux/init.h>
14 #include <linux/interrupt.h>
15 #include <linux/module.h>
16 #include <linux/console.h>
17 #include <linux/tty.h>
18 #include <linux/tty_flip.h>
19 #include <linux/serial.h>
20 #include <linux/serial_core.h>
21 #include <linux/io.h>
22 #include <linux/uaccess.h>
23 #include <linux/platform_device.h>
24 #include <asm/coldfire.h>
25 #include <asm/mcfsim.h>
26 #include <asm/mcfuart.h>
27 #include <asm/nettel.h>
28 
29 /****************************************************************************/
30 
31 /*
32  *	Some boards implement the DTR/DCD lines using GPIO lines, most
33  *	don't. Dummy out the access macros for those that don't. Those
34  *	that do should define these macros somewhere in there board
35  *	specific inlude files.
36  */
37 #if !defined(mcf_getppdcd)
38 #define	mcf_getppdcd(p)		(1)
39 #endif
40 #if !defined(mcf_getppdtr)
41 #define	mcf_getppdtr(p)		(1)
42 #endif
43 #if !defined(mcf_setppdtr)
44 #define	mcf_setppdtr(p, v)	do { } while (0)
45 #endif
46 
47 /****************************************************************************/
48 
49 /*
50  *	Local per-uart structure.
51  */
52 struct mcf_uart {
53 	struct uart_port	port;
54 	unsigned int		sigs;		/* Local copy of line sigs */
55 	unsigned char		imr;		/* Local IMR mirror */
56 };
57 
58 /****************************************************************************/
59 
60 static unsigned int mcf_tx_empty(struct uart_port *port)
61 {
62 	return (readb(port->membase + MCFUART_USR) & MCFUART_USR_TXEMPTY) ?
63 		TIOCSER_TEMT : 0;
64 }
65 
66 /****************************************************************************/
67 
68 static unsigned int mcf_get_mctrl(struct uart_port *port)
69 {
70 	struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
71 	unsigned int sigs;
72 
73 	sigs = (readb(port->membase + MCFUART_UIPR) & MCFUART_UIPR_CTS) ?
74 		0 : TIOCM_CTS;
75 	sigs |= (pp->sigs & TIOCM_RTS);
76 	sigs |= (mcf_getppdcd(port->line) ? TIOCM_CD : 0);
77 	sigs |= (mcf_getppdtr(port->line) ? TIOCM_DTR : 0);
78 
79 	return sigs;
80 }
81 
82 /****************************************************************************/
83 
84 static void mcf_set_mctrl(struct uart_port *port, unsigned int sigs)
85 {
86 	struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
87 
88 	pp->sigs = sigs;
89 	mcf_setppdtr(port->line, (sigs & TIOCM_DTR));
90 	if (sigs & TIOCM_RTS)
91 		writeb(MCFUART_UOP_RTS, port->membase + MCFUART_UOP1);
92 	else
93 		writeb(MCFUART_UOP_RTS, port->membase + MCFUART_UOP0);
94 }
95 
96 /****************************************************************************/
97 
98 static void mcf_start_tx(struct uart_port *port)
99 {
100 	struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
101 
102 	if (port->rs485.flags & SER_RS485_ENABLED) {
103 		/* Enable Transmitter */
104 		writeb(MCFUART_UCR_TXENABLE, port->membase + MCFUART_UCR);
105 		/* Manually assert RTS */
106 		writeb(MCFUART_UOP_RTS, port->membase + MCFUART_UOP1);
107 	}
108 	pp->imr |= MCFUART_UIR_TXREADY;
109 	writeb(pp->imr, port->membase + MCFUART_UIMR);
110 }
111 
112 /****************************************************************************/
113 
114 static void mcf_stop_tx(struct uart_port *port)
115 {
116 	struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
117 
118 	pp->imr &= ~MCFUART_UIR_TXREADY;
119 	writeb(pp->imr, port->membase + MCFUART_UIMR);
120 }
121 
122 /****************************************************************************/
123 
124 static void mcf_stop_rx(struct uart_port *port)
125 {
126 	struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
127 
128 	pp->imr &= ~MCFUART_UIR_RXREADY;
129 	writeb(pp->imr, port->membase + MCFUART_UIMR);
130 }
131 
132 /****************************************************************************/
133 
134 static void mcf_break_ctl(struct uart_port *port, int break_state)
135 {
136 	unsigned long flags;
137 
138 	uart_port_lock_irqsave(port, &flags);
139 	if (break_state == -1)
140 		writeb(MCFUART_UCR_CMDBREAKSTART, port->membase + MCFUART_UCR);
141 	else
142 		writeb(MCFUART_UCR_CMDBREAKSTOP, port->membase + MCFUART_UCR);
143 	uart_port_unlock_irqrestore(port, flags);
144 }
145 
146 /****************************************************************************/
147 
148 static int mcf_startup(struct uart_port *port)
149 {
150 	struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
151 	unsigned long flags;
152 
153 	uart_port_lock_irqsave(port, &flags);
154 
155 	/* Reset UART, get it into known state... */
156 	writeb(MCFUART_UCR_CMDRESETRX, port->membase + MCFUART_UCR);
157 	writeb(MCFUART_UCR_CMDRESETTX, port->membase + MCFUART_UCR);
158 
159 	/* Enable the UART transmitter and receiver */
160 	writeb(MCFUART_UCR_RXENABLE | MCFUART_UCR_TXENABLE,
161 		port->membase + MCFUART_UCR);
162 
163 	/* Enable RX interrupts now */
164 	pp->imr = MCFUART_UIR_RXREADY;
165 	writeb(pp->imr, port->membase + MCFUART_UIMR);
166 
167 	uart_port_unlock_irqrestore(port, flags);
168 
169 	return 0;
170 }
171 
172 /****************************************************************************/
173 
174 static void mcf_shutdown(struct uart_port *port)
175 {
176 	struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
177 	unsigned long flags;
178 
179 	uart_port_lock_irqsave(port, &flags);
180 
181 	/* Disable all interrupts now */
182 	pp->imr = 0;
183 	writeb(pp->imr, port->membase + MCFUART_UIMR);
184 
185 	/* Disable UART transmitter and receiver */
186 	writeb(MCFUART_UCR_CMDRESETRX, port->membase + MCFUART_UCR);
187 	writeb(MCFUART_UCR_CMDRESETTX, port->membase + MCFUART_UCR);
188 
189 	uart_port_unlock_irqrestore(port, flags);
190 }
191 
192 /****************************************************************************/
193 
194 static void mcf_set_termios(struct uart_port *port, struct ktermios *termios,
195 			    const struct ktermios *old)
196 {
197 	unsigned long flags;
198 	unsigned int baud, baudclk;
199 #if defined(CONFIG_M5272)
200 	unsigned int baudfr;
201 #endif
202 	unsigned char mr1, mr2;
203 
204 	baud = uart_get_baud_rate(port, termios, old, 0, 230400);
205 #if defined(CONFIG_M5272)
206 	baudclk = (MCF_BUSCLK / baud) / 32;
207 	baudfr = (((MCF_BUSCLK / baud) + 1) / 2) % 16;
208 #else
209 	baudclk = ((MCF_BUSCLK / baud) + 16) / 32;
210 #endif
211 
212 	mr1 = MCFUART_MR1_RXIRQRDY | MCFUART_MR1_RXERRCHAR;
213 	mr2 = 0;
214 
215 	switch (termios->c_cflag & CSIZE) {
216 	case CS5: mr1 |= MCFUART_MR1_CS5; break;
217 	case CS6: mr1 |= MCFUART_MR1_CS6; break;
218 	case CS7: mr1 |= MCFUART_MR1_CS7; break;
219 	case CS8:
220 	default:  mr1 |= MCFUART_MR1_CS8; break;
221 	}
222 
223 	if (termios->c_cflag & PARENB) {
224 		if (termios->c_cflag & CMSPAR) {
225 			if (termios->c_cflag & PARODD)
226 				mr1 |= MCFUART_MR1_PARITYMARK;
227 			else
228 				mr1 |= MCFUART_MR1_PARITYSPACE;
229 		} else {
230 			if (termios->c_cflag & PARODD)
231 				mr1 |= MCFUART_MR1_PARITYODD;
232 			else
233 				mr1 |= MCFUART_MR1_PARITYEVEN;
234 		}
235 	} else {
236 		mr1 |= MCFUART_MR1_PARITYNONE;
237 	}
238 
239 	/*
240 	 * FIXME: port->read_status_mask and port->ignore_status_mask
241 	 * need to be initialized based on termios settings for
242 	 * INPCK, IGNBRK, IGNPAR, PARMRK, BRKINT
243 	 */
244 
245 	if (termios->c_cflag & CSTOPB)
246 		mr2 |= MCFUART_MR2_STOP2;
247 	else
248 		mr2 |= MCFUART_MR2_STOP1;
249 
250 	if (termios->c_cflag & CRTSCTS) {
251 		mr1 |= MCFUART_MR1_RXRTS;
252 		mr2 |= MCFUART_MR2_TXCTS;
253 	}
254 
255 	uart_port_lock_irqsave(port, &flags);
256 	if (port->rs485.flags & SER_RS485_ENABLED) {
257 		dev_dbg(port->dev, "Setting UART to RS485\n");
258 		mr2 |= MCFUART_MR2_TXRTS;
259 	}
260 
261 	uart_update_timeout(port, termios->c_cflag, baud);
262 	writeb(MCFUART_UCR_CMDRESETRX, port->membase + MCFUART_UCR);
263 	writeb(MCFUART_UCR_CMDRESETTX, port->membase + MCFUART_UCR);
264 	writeb(MCFUART_UCR_CMDRESETMRPTR, port->membase + MCFUART_UCR);
265 	writeb(mr1, port->membase + MCFUART_UMR);
266 	writeb(mr2, port->membase + MCFUART_UMR);
267 	writeb((baudclk & 0xff00) >> 8, port->membase + MCFUART_UBG1);
268 	writeb((baudclk & 0xff), port->membase + MCFUART_UBG2);
269 #if defined(CONFIG_M5272)
270 	writeb((baudfr & 0x0f), port->membase + MCFUART_UFPD);
271 #endif
272 	writeb(MCFUART_UCSR_RXCLKTIMER | MCFUART_UCSR_TXCLKTIMER,
273 		port->membase + MCFUART_UCSR);
274 	writeb(MCFUART_UCR_RXENABLE | MCFUART_UCR_TXENABLE,
275 		port->membase + MCFUART_UCR);
276 	uart_port_unlock_irqrestore(port, flags);
277 }
278 
279 /****************************************************************************/
280 
281 static void mcf_rx_chars(struct mcf_uart *pp)
282 {
283 	struct uart_port *port = &pp->port;
284 	u8 status, ch, flag;
285 
286 	while ((status = readb(port->membase + MCFUART_USR)) & MCFUART_USR_RXREADY) {
287 		ch = readb(port->membase + MCFUART_URB);
288 		flag = TTY_NORMAL;
289 		port->icount.rx++;
290 
291 		if (status & MCFUART_USR_RXERR) {
292 			writeb(MCFUART_UCR_CMDRESETERR,
293 				port->membase + MCFUART_UCR);
294 
295 			if (status & MCFUART_USR_RXBREAK) {
296 				port->icount.brk++;
297 				if (uart_handle_break(port))
298 					continue;
299 			} else if (status & MCFUART_USR_RXPARITY) {
300 				port->icount.parity++;
301 			} else if (status & MCFUART_USR_RXOVERRUN) {
302 				port->icount.overrun++;
303 			} else if (status & MCFUART_USR_RXFRAMING) {
304 				port->icount.frame++;
305 			}
306 
307 			status &= port->read_status_mask;
308 
309 			if (status & MCFUART_USR_RXBREAK)
310 				flag = TTY_BREAK;
311 			else if (status & MCFUART_USR_RXPARITY)
312 				flag = TTY_PARITY;
313 			else if (status & MCFUART_USR_RXFRAMING)
314 				flag = TTY_FRAME;
315 		}
316 
317 		if (uart_handle_sysrq_char(port, ch))
318 			continue;
319 		uart_insert_char(port, status, MCFUART_USR_RXOVERRUN, ch, flag);
320 	}
321 
322 	tty_flip_buffer_push(&port->state->port);
323 }
324 
325 /****************************************************************************/
326 
327 static void mcf_tx_chars(struct mcf_uart *pp)
328 {
329 	struct uart_port *port = &pp->port;
330 	bool pending;
331 	u8 ch;
332 
333 	pending = uart_port_tx(port, ch,
334 		readb(port->membase + MCFUART_USR) & MCFUART_USR_TXREADY,
335 		writeb(ch, port->membase + MCFUART_UTB));
336 
337 	/* Disable TX to negate RTS automatically */
338 	if (!pending && (port->rs485.flags & SER_RS485_ENABLED))
339 		writeb(MCFUART_UCR_TXDISABLE, port->membase + MCFUART_UCR);
340 }
341 
342 /****************************************************************************/
343 
344 static irqreturn_t mcf_interrupt(int irq, void *data)
345 {
346 	struct uart_port *port = data;
347 	struct mcf_uart *pp = container_of(port, struct mcf_uart, port);
348 	unsigned int isr;
349 	irqreturn_t ret = IRQ_NONE;
350 
351 	isr = readb(port->membase + MCFUART_UISR) & pp->imr;
352 
353 	uart_port_lock(port);
354 	if (isr & MCFUART_UIR_RXREADY) {
355 		mcf_rx_chars(pp);
356 		ret = IRQ_HANDLED;
357 	}
358 	if (isr & MCFUART_UIR_TXREADY) {
359 		mcf_tx_chars(pp);
360 		ret = IRQ_HANDLED;
361 	}
362 	uart_port_unlock(port);
363 
364 	return ret;
365 }
366 
367 /****************************************************************************/
368 
369 static void mcf_config_port(struct uart_port *port, int flags)
370 {
371 	port->type = PORT_MCF;
372 	port->fifosize = MCFUART_TXFIFOSIZE;
373 
374 	/* Clear mask, so no surprise interrupts. */
375 	writeb(0, port->membase + MCFUART_UIMR);
376 
377 	if (request_irq(port->irq, mcf_interrupt, 0, "UART", port))
378 		printk(KERN_ERR "MCF: unable to attach ColdFire UART %d "
379 			"interrupt vector=%d\n", port->line, port->irq);
380 }
381 
382 /****************************************************************************/
383 
384 static const char *mcf_type(struct uart_port *port)
385 {
386 	return (port->type == PORT_MCF) ? "ColdFire UART" : NULL;
387 }
388 
389 /****************************************************************************/
390 
391 static int mcf_request_port(struct uart_port *port)
392 {
393 	/* UARTs always present */
394 	return 0;
395 }
396 
397 /****************************************************************************/
398 
399 static void mcf_release_port(struct uart_port *port)
400 {
401 	/* Nothing to release... */
402 }
403 
404 /****************************************************************************/
405 
406 static int mcf_verify_port(struct uart_port *port, struct serial_struct *ser)
407 {
408 	if ((ser->type != PORT_UNKNOWN) && (ser->type != PORT_MCF))
409 		return -EINVAL;
410 	return 0;
411 }
412 
413 /****************************************************************************/
414 
415 /* Enable or disable the RS485 support */
416 static int mcf_config_rs485(struct uart_port *port, struct ktermios *termios,
417 			    struct serial_rs485 *rs485)
418 {
419 	unsigned char mr1, mr2;
420 
421 	/* Get mode registers */
422 	mr1 = readb(port->membase + MCFUART_UMR);
423 	mr2 = readb(port->membase + MCFUART_UMR);
424 	if (rs485->flags & SER_RS485_ENABLED) {
425 		dev_dbg(port->dev, "Setting UART to RS485\n");
426 		/* Automatically negate RTS after TX completes */
427 		mr2 |= MCFUART_MR2_TXRTS;
428 	} else {
429 		dev_dbg(port->dev, "Setting UART to RS232\n");
430 		mr2 &= ~MCFUART_MR2_TXRTS;
431 	}
432 	writeb(mr1, port->membase + MCFUART_UMR);
433 	writeb(mr2, port->membase + MCFUART_UMR);
434 
435 	return 0;
436 }
437 
438 static const struct serial_rs485 mcf_rs485_supported = {
439 	.flags = SER_RS485_ENABLED | SER_RS485_RTS_AFTER_SEND,
440 };
441 
442 /****************************************************************************/
443 
444 /*
445  *	Define the basic serial functions we support.
446  */
447 static const struct uart_ops mcf_uart_ops = {
448 	.tx_empty	= mcf_tx_empty,
449 	.get_mctrl	= mcf_get_mctrl,
450 	.set_mctrl	= mcf_set_mctrl,
451 	.start_tx	= mcf_start_tx,
452 	.stop_tx	= mcf_stop_tx,
453 	.stop_rx	= mcf_stop_rx,
454 	.break_ctl	= mcf_break_ctl,
455 	.startup	= mcf_startup,
456 	.shutdown	= mcf_shutdown,
457 	.set_termios	= mcf_set_termios,
458 	.type		= mcf_type,
459 	.request_port	= mcf_request_port,
460 	.release_port	= mcf_release_port,
461 	.config_port	= mcf_config_port,
462 	.verify_port	= mcf_verify_port,
463 };
464 
465 static struct mcf_uart mcf_ports[4];
466 
467 #define	MCF_MAXPORTS	ARRAY_SIZE(mcf_ports)
468 
469 /****************************************************************************/
470 #if defined(CONFIG_SERIAL_MCF_CONSOLE)
471 /****************************************************************************/
472 
473 static void mcf_console_putc(struct console *co, const char c)
474 {
475 	struct uart_port *port = &(mcf_ports + co->index)->port;
476 	int i;
477 
478 	for (i = 0; (i < 0x10000); i++) {
479 		if (readb(port->membase + MCFUART_USR) & MCFUART_USR_TXREADY)
480 			break;
481 	}
482 	writeb(c, port->membase + MCFUART_UTB);
483 	for (i = 0; (i < 0x10000); i++) {
484 		if (readb(port->membase + MCFUART_USR) & MCFUART_USR_TXREADY)
485 			break;
486 	}
487 }
488 
489 /****************************************************************************/
490 
491 static void mcf_console_write(struct console *co, const char *s, unsigned int count)
492 {
493 	for (; (count); count--, s++) {
494 		mcf_console_putc(co, *s);
495 		if (*s == '\n')
496 			mcf_console_putc(co, '\r');
497 	}
498 }
499 
500 /****************************************************************************/
501 
502 static int __init mcf_console_setup(struct console *co, char *options)
503 {
504 	struct uart_port *port;
505 	int baud = CONFIG_SERIAL_MCF_BAUDRATE;
506 	int bits = 8;
507 	int parity = 'n';
508 	int flow = 'n';
509 
510 	if ((co->index < 0) || (co->index >= MCF_MAXPORTS))
511 		co->index = 0;
512 	port = &mcf_ports[co->index].port;
513 	if (port->membase == 0)
514 		return -ENODEV;
515 
516 	if (options)
517 		uart_parse_options(options, &baud, &parity, &bits, &flow);
518 
519 	return uart_set_options(port, co, baud, parity, bits, flow);
520 }
521 
522 /****************************************************************************/
523 
524 static struct uart_driver mcf_driver;
525 
526 static struct console mcf_console = {
527 	.name		= "ttyS",
528 	.write		= mcf_console_write,
529 	.device		= uart_console_device,
530 	.setup		= mcf_console_setup,
531 	.flags		= CON_PRINTBUFFER,
532 	.index		= -1,
533 	.data		= &mcf_driver,
534 };
535 
536 static int __init mcf_console_init(void)
537 {
538 	register_console(&mcf_console);
539 	return 0;
540 }
541 
542 console_initcall(mcf_console_init);
543 
544 #define	MCF_CONSOLE	&mcf_console
545 
546 /****************************************************************************/
547 #else
548 /****************************************************************************/
549 
550 #define	MCF_CONSOLE	NULL
551 
552 /****************************************************************************/
553 #endif /* CONFIG_SERIAL_MCF_CONSOLE */
554 /****************************************************************************/
555 
556 /*
557  *	Define the mcf UART driver structure.
558  */
559 static struct uart_driver mcf_driver = {
560 	.owner		= THIS_MODULE,
561 	.driver_name	= "mcf",
562 	.dev_name	= "ttyS",
563 	.major		= TTY_MAJOR,
564 	.minor		= 64,
565 	.nr		= MCF_MAXPORTS,
566 	.cons		= MCF_CONSOLE,
567 };
568 
569 /****************************************************************************/
570 
571 static int mcf_probe(struct platform_device *pdev)
572 {
573 	struct mcf_platform_uart *platp = dev_get_platdata(&pdev->dev);
574 	struct uart_port *port;
575 	int i;
576 
577 	for (i = 0; ((i < MCF_MAXPORTS) && (platp[i].mapbase)); i++) {
578 		port = &mcf_ports[i].port;
579 
580 		port->line = i;
581 		port->type = PORT_MCF;
582 		port->mapbase = platp[i].mapbase;
583 		port->membase = (platp[i].membase) ? platp[i].membase :
584 			(unsigned char __iomem *) platp[i].mapbase;
585 		port->dev = &pdev->dev;
586 		port->iotype = SERIAL_IO_MEM;
587 		port->irq = platp[i].irq;
588 		port->uartclk = MCF_BUSCLK;
589 		port->ops = &mcf_uart_ops;
590 		port->flags = UPF_BOOT_AUTOCONF;
591 		port->rs485_config = mcf_config_rs485;
592 		port->rs485_supported = mcf_rs485_supported;
593 		port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_MCF_CONSOLE);
594 
595 		uart_add_one_port(&mcf_driver, port);
596 	}
597 
598 	return 0;
599 }
600 
601 /****************************************************************************/
602 
603 static void mcf_remove(struct platform_device *pdev)
604 {
605 	struct uart_port *port;
606 	int i;
607 
608 	for (i = 0; (i < MCF_MAXPORTS); i++) {
609 		port = &mcf_ports[i].port;
610 		if (port)
611 			uart_remove_one_port(&mcf_driver, port);
612 	}
613 }
614 
615 /****************************************************************************/
616 
617 static struct platform_driver mcf_platform_driver = {
618 	.probe		= mcf_probe,
619 	.remove_new	= mcf_remove,
620 	.driver		= {
621 		.name	= "mcfuart",
622 	},
623 };
624 
625 /****************************************************************************/
626 
627 static int __init mcf_init(void)
628 {
629 	int rc;
630 
631 	printk("ColdFire internal UART serial driver\n");
632 
633 	rc = uart_register_driver(&mcf_driver);
634 	if (rc)
635 		return rc;
636 	rc = platform_driver_register(&mcf_platform_driver);
637 	if (rc) {
638 		uart_unregister_driver(&mcf_driver);
639 		return rc;
640 	}
641 	return 0;
642 }
643 
644 /****************************************************************************/
645 
646 static void __exit mcf_exit(void)
647 {
648 	platform_driver_unregister(&mcf_platform_driver);
649 	uart_unregister_driver(&mcf_driver);
650 }
651 
652 /****************************************************************************/
653 
654 module_init(mcf_init);
655 module_exit(mcf_exit);
656 
657 MODULE_AUTHOR("Greg Ungerer <gerg@uclinux.org>");
658 MODULE_DESCRIPTION("Freescale ColdFire UART driver");
659 MODULE_LICENSE("GPL");
660 MODULE_ALIAS("platform:mcfuart");
661 
662 /****************************************************************************/
663