xref: /openbmc/linux/drivers/tty/serial/dz.c (revision ee160a38)
1 /*
2  * dz.c: Serial port driver for DECstations equipped
3  *       with the DZ chipset.
4  *
5  * Copyright (C) 1998 Olivier A. D. Lebaillif
6  *
7  * Email: olivier.lebaillif@ifrsys.com
8  *
9  * Copyright (C) 2004, 2006, 2007  Maciej W. Rozycki
10  *
11  * [31-AUG-98] triemer
12  * Changed IRQ to use Harald's dec internals interrupts.h
13  * removed base_addr code - moving address assignment to setup.c
14  * Changed name of dz_init to rs_init to be consistent with tc code
15  * [13-NOV-98] triemer fixed code to receive characters
16  *    after patches by harald to irq code.
17  * [09-JAN-99] triemer minor fix for schedule - due to removal of timeout
18  *            field from "current" - somewhere between 2.1.121 and 2.1.131
19  Qua Jun 27 15:02:26 BRT 2001
20  * [27-JUN-2001] Arnaldo Carvalho de Melo <acme@conectiva.com.br> - cleanups
21  *
22  * Parts (C) 1999 David Airlie, airlied@linux.ie
23  * [07-SEP-99] Bugfixes
24  *
25  * [06-Jan-2002] Russell King <rmk@arm.linux.org.uk>
26  * Converted to new serial core
27  */
28 
29 #undef DEBUG_DZ
30 
31 #if defined(CONFIG_SERIAL_DZ_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
32 #define SUPPORT_SYSRQ
33 #endif
34 
35 #include <linux/bitops.h>
36 #include <linux/compiler.h>
37 #include <linux/console.h>
38 #include <linux/delay.h>
39 #include <linux/errno.h>
40 #include <linux/init.h>
41 #include <linux/interrupt.h>
42 #include <linux/ioport.h>
43 #include <linux/kernel.h>
44 #include <linux/major.h>
45 #include <linux/module.h>
46 #include <linux/serial.h>
47 #include <linux/serial_core.h>
48 #include <linux/sysrq.h>
49 #include <linux/tty.h>
50 #include <linux/tty_flip.h>
51 
52 #include <linux/atomic.h>
53 #include <asm/bootinfo.h>
54 #include <asm/io.h>
55 #include <asm/system.h>
56 
57 #include <asm/dec/interrupts.h>
58 #include <asm/dec/kn01.h>
59 #include <asm/dec/kn02.h>
60 #include <asm/dec/machtype.h>
61 #include <asm/dec/prom.h>
62 #include <asm/dec/system.h>
63 
64 #include "dz.h"
65 
66 
67 MODULE_DESCRIPTION("DECstation DZ serial driver");
68 MODULE_LICENSE("GPL");
69 
70 
71 static char dz_name[] __initdata = "DECstation DZ serial driver version ";
72 static char dz_version[] __initdata = "1.04";
73 
74 struct dz_port {
75 	struct dz_mux		*mux;
76 	struct uart_port	port;
77 	unsigned int		cflag;
78 };
79 
80 struct dz_mux {
81 	struct dz_port		dport[DZ_NB_PORT];
82 	atomic_t		map_guard;
83 	atomic_t		irq_guard;
84 	int			initialised;
85 };
86 
87 static struct dz_mux dz_mux;
88 
89 static inline struct dz_port *to_dport(struct uart_port *uport)
90 {
91 	return container_of(uport, struct dz_port, port);
92 }
93 
94 /*
95  * ------------------------------------------------------------
96  * dz_in () and dz_out ()
97  *
98  * These routines are used to access the registers of the DZ
99  * chip, hiding relocation differences between implementation.
100  * ------------------------------------------------------------
101  */
102 
103 static u16 dz_in(struct dz_port *dport, unsigned offset)
104 {
105 	void __iomem *addr = dport->port.membase + offset;
106 
107 	return readw(addr);
108 }
109 
110 static void dz_out(struct dz_port *dport, unsigned offset, u16 value)
111 {
112 	void __iomem *addr = dport->port.membase + offset;
113 
114 	writew(value, addr);
115 }
116 
117 /*
118  * ------------------------------------------------------------
119  * rs_stop () and rs_start ()
120  *
121  * These routines are called before setting or resetting
122  * tty->stopped. They enable or disable transmitter interrupts,
123  * as necessary.
124  * ------------------------------------------------------------
125  */
126 
127 static void dz_stop_tx(struct uart_port *uport)
128 {
129 	struct dz_port *dport = to_dport(uport);
130 	u16 tmp, mask = 1 << dport->port.line;
131 
132 	tmp = dz_in(dport, DZ_TCR);	/* read the TX flag */
133 	tmp &= ~mask;			/* clear the TX flag */
134 	dz_out(dport, DZ_TCR, tmp);
135 }
136 
137 static void dz_start_tx(struct uart_port *uport)
138 {
139 	struct dz_port *dport = to_dport(uport);
140 	u16 tmp, mask = 1 << dport->port.line;
141 
142 	tmp = dz_in(dport, DZ_TCR);	/* read the TX flag */
143 	tmp |= mask;			/* set the TX flag */
144 	dz_out(dport, DZ_TCR, tmp);
145 }
146 
147 static void dz_stop_rx(struct uart_port *uport)
148 {
149 	struct dz_port *dport = to_dport(uport);
150 
151 	dport->cflag &= ~DZ_RXENAB;
152 	dz_out(dport, DZ_LPR, dport->cflag);
153 }
154 
155 static void dz_enable_ms(struct uart_port *uport)
156 {
157 	/* nothing to do */
158 }
159 
160 /*
161  * ------------------------------------------------------------
162  *
163  * Here start the interrupt handling routines.  All of the following
164  * subroutines are declared as inline and are folded into
165  * dz_interrupt.  They were separated out for readability's sake.
166  *
167  * Note: dz_interrupt() is a "fast" interrupt, which means that it
168  * runs with interrupts turned off.  People who may want to modify
169  * dz_interrupt() should try to keep the interrupt handler as fast as
170  * possible.  After you are done making modifications, it is not a bad
171  * idea to do:
172  *
173  *	make drivers/serial/dz.s
174  *
175  * and look at the resulting assemble code in dz.s.
176  *
177  * ------------------------------------------------------------
178  */
179 
180 /*
181  * ------------------------------------------------------------
182  * receive_char ()
183  *
184  * This routine deals with inputs from any lines.
185  * ------------------------------------------------------------
186  */
187 static inline void dz_receive_chars(struct dz_mux *mux)
188 {
189 	struct uart_port *uport;
190 	struct dz_port *dport = &mux->dport[0];
191 	struct tty_struct *tty = NULL;
192 	struct uart_icount *icount;
193 	int lines_rx[DZ_NB_PORT] = { [0 ... DZ_NB_PORT - 1] = 0 };
194 	unsigned char ch, flag;
195 	u16 status;
196 	int i;
197 
198 	while ((status = dz_in(dport, DZ_RBUF)) & DZ_DVAL) {
199 		dport = &mux->dport[LINE(status)];
200 		uport = &dport->port;
201 		tty = uport->state->port.tty;	/* point to the proper dev */
202 
203 		ch = UCHAR(status);		/* grab the char */
204 		flag = TTY_NORMAL;
205 
206 		icount = &uport->icount;
207 		icount->rx++;
208 
209 		if (unlikely(status & (DZ_OERR | DZ_FERR | DZ_PERR))) {
210 
211 			/*
212 			 * There is no separate BREAK status bit, so treat
213 			 * null characters with framing errors as BREAKs;
214 			 * normally, otherwise.  For this move the Framing
215 			 * Error bit to a simulated BREAK bit.
216 			 */
217 			if (!ch) {
218 				status |= (status & DZ_FERR) >>
219 					  (ffs(DZ_FERR) - ffs(DZ_BREAK));
220 				status &= ~DZ_FERR;
221 			}
222 
223 			/* Handle SysRq/SAK & keep track of the statistics. */
224 			if (status & DZ_BREAK) {
225 				icount->brk++;
226 				if (uart_handle_break(uport))
227 					continue;
228 			} else if (status & DZ_FERR)
229 				icount->frame++;
230 			else if (status & DZ_PERR)
231 				icount->parity++;
232 			if (status & DZ_OERR)
233 				icount->overrun++;
234 
235 			status &= uport->read_status_mask;
236 			if (status & DZ_BREAK)
237 				flag = TTY_BREAK;
238 			else if (status & DZ_FERR)
239 				flag = TTY_FRAME;
240 			else if (status & DZ_PERR)
241 				flag = TTY_PARITY;
242 
243 		}
244 
245 		if (uart_handle_sysrq_char(uport, ch))
246 			continue;
247 
248 		uart_insert_char(uport, status, DZ_OERR, ch, flag);
249 		lines_rx[LINE(status)] = 1;
250 	}
251 	for (i = 0; i < DZ_NB_PORT; i++)
252 		if (lines_rx[i])
253 			tty_flip_buffer_push(mux->dport[i].port.state->port.tty);
254 }
255 
256 /*
257  * ------------------------------------------------------------
258  * transmit_char ()
259  *
260  * This routine deals with outputs to any lines.
261  * ------------------------------------------------------------
262  */
263 static inline void dz_transmit_chars(struct dz_mux *mux)
264 {
265 	struct dz_port *dport = &mux->dport[0];
266 	struct circ_buf *xmit;
267 	unsigned char tmp;
268 	u16 status;
269 
270 	status = dz_in(dport, DZ_CSR);
271 	dport = &mux->dport[LINE(status)];
272 	xmit = &dport->port.state->xmit;
273 
274 	if (dport->port.x_char) {		/* XON/XOFF chars */
275 		dz_out(dport, DZ_TDR, dport->port.x_char);
276 		dport->port.icount.tx++;
277 		dport->port.x_char = 0;
278 		return;
279 	}
280 	/* If nothing to do or stopped or hardware stopped. */
281 	if (uart_circ_empty(xmit) || uart_tx_stopped(&dport->port)) {
282 		spin_lock(&dport->port.lock);
283 		dz_stop_tx(&dport->port);
284 		spin_unlock(&dport->port.lock);
285 		return;
286 	}
287 
288 	/*
289 	 * If something to do... (remember the dz has no output fifo,
290 	 * so we go one char at a time) :-<
291 	 */
292 	tmp = xmit->buf[xmit->tail];
293 	xmit->tail = (xmit->tail + 1) & (DZ_XMIT_SIZE - 1);
294 	dz_out(dport, DZ_TDR, tmp);
295 	dport->port.icount.tx++;
296 
297 	if (uart_circ_chars_pending(xmit) < DZ_WAKEUP_CHARS)
298 		uart_write_wakeup(&dport->port);
299 
300 	/* Are we are done. */
301 	if (uart_circ_empty(xmit)) {
302 		spin_lock(&dport->port.lock);
303 		dz_stop_tx(&dport->port);
304 		spin_unlock(&dport->port.lock);
305 	}
306 }
307 
308 /*
309  * ------------------------------------------------------------
310  * check_modem_status()
311  *
312  * DS 3100 & 5100: Only valid for the MODEM line, duh!
313  * DS 5000/200: Valid for the MODEM and PRINTER line.
314  * ------------------------------------------------------------
315  */
316 static inline void check_modem_status(struct dz_port *dport)
317 {
318 	/*
319 	 * FIXME:
320 	 * 1. No status change interrupt; use a timer.
321 	 * 2. Handle the 3100/5000 as appropriate. --macro
322 	 */
323 	u16 status;
324 
325 	/* If not the modem line just return.  */
326 	if (dport->port.line != DZ_MODEM)
327 		return;
328 
329 	status = dz_in(dport, DZ_MSR);
330 
331 	/* it's easy, since DSR2 is the only bit in the register */
332 	if (status)
333 		dport->port.icount.dsr++;
334 }
335 
336 /*
337  * ------------------------------------------------------------
338  * dz_interrupt ()
339  *
340  * this is the main interrupt routine for the DZ chip.
341  * It deals with the multiple ports.
342  * ------------------------------------------------------------
343  */
344 static irqreturn_t dz_interrupt(int irq, void *dev_id)
345 {
346 	struct dz_mux *mux = dev_id;
347 	struct dz_port *dport = &mux->dport[0];
348 	u16 status;
349 
350 	/* get the reason why we just got an irq */
351 	status = dz_in(dport, DZ_CSR);
352 
353 	if ((status & (DZ_RDONE | DZ_RIE)) == (DZ_RDONE | DZ_RIE))
354 		dz_receive_chars(mux);
355 
356 	if ((status & (DZ_TRDY | DZ_TIE)) == (DZ_TRDY | DZ_TIE))
357 		dz_transmit_chars(mux);
358 
359 	return IRQ_HANDLED;
360 }
361 
362 /*
363  * -------------------------------------------------------------------
364  * Here ends the DZ interrupt routines.
365  * -------------------------------------------------------------------
366  */
367 
368 static unsigned int dz_get_mctrl(struct uart_port *uport)
369 {
370 	/*
371 	 * FIXME: Handle the 3100/5000 as appropriate. --macro
372 	 */
373 	struct dz_port *dport = to_dport(uport);
374 	unsigned int mctrl = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
375 
376 	if (dport->port.line == DZ_MODEM) {
377 		if (dz_in(dport, DZ_MSR) & DZ_MODEM_DSR)
378 			mctrl &= ~TIOCM_DSR;
379 	}
380 
381 	return mctrl;
382 }
383 
384 static void dz_set_mctrl(struct uart_port *uport, unsigned int mctrl)
385 {
386 	/*
387 	 * FIXME: Handle the 3100/5000 as appropriate. --macro
388 	 */
389 	struct dz_port *dport = to_dport(uport);
390 	u16 tmp;
391 
392 	if (dport->port.line == DZ_MODEM) {
393 		tmp = dz_in(dport, DZ_TCR);
394 		if (mctrl & TIOCM_DTR)
395 			tmp &= ~DZ_MODEM_DTR;
396 		else
397 			tmp |= DZ_MODEM_DTR;
398 		dz_out(dport, DZ_TCR, tmp);
399 	}
400 }
401 
402 /*
403  * -------------------------------------------------------------------
404  * startup ()
405  *
406  * various initialization tasks
407  * -------------------------------------------------------------------
408  */
409 static int dz_startup(struct uart_port *uport)
410 {
411 	struct dz_port *dport = to_dport(uport);
412 	struct dz_mux *mux = dport->mux;
413 	unsigned long flags;
414 	int irq_guard;
415 	int ret;
416 	u16 tmp;
417 
418 	irq_guard = atomic_add_return(1, &mux->irq_guard);
419 	if (irq_guard != 1)
420 		return 0;
421 
422 	ret = request_irq(dport->port.irq, dz_interrupt,
423 			  IRQF_SHARED, "dz", mux);
424 	if (ret) {
425 		atomic_add(-1, &mux->irq_guard);
426 		printk(KERN_ERR "dz: Cannot get IRQ %d!\n", dport->port.irq);
427 		return ret;
428 	}
429 
430 	spin_lock_irqsave(&dport->port.lock, flags);
431 
432 	/* Enable interrupts.  */
433 	tmp = dz_in(dport, DZ_CSR);
434 	tmp |= DZ_RIE | DZ_TIE;
435 	dz_out(dport, DZ_CSR, tmp);
436 
437 	spin_unlock_irqrestore(&dport->port.lock, flags);
438 
439 	return 0;
440 }
441 
442 /*
443  * -------------------------------------------------------------------
444  * shutdown ()
445  *
446  * This routine will shutdown a serial port; interrupts are disabled, and
447  * DTR is dropped if the hangup on close termio flag is on.
448  * -------------------------------------------------------------------
449  */
450 static void dz_shutdown(struct uart_port *uport)
451 {
452 	struct dz_port *dport = to_dport(uport);
453 	struct dz_mux *mux = dport->mux;
454 	unsigned long flags;
455 	int irq_guard;
456 	u16 tmp;
457 
458 	spin_lock_irqsave(&dport->port.lock, flags);
459 	dz_stop_tx(&dport->port);
460 	spin_unlock_irqrestore(&dport->port.lock, flags);
461 
462 	irq_guard = atomic_add_return(-1, &mux->irq_guard);
463 	if (!irq_guard) {
464 		/* Disable interrupts.  */
465 		tmp = dz_in(dport, DZ_CSR);
466 		tmp &= ~(DZ_RIE | DZ_TIE);
467 		dz_out(dport, DZ_CSR, tmp);
468 
469 		free_irq(dport->port.irq, mux);
470 	}
471 }
472 
473 /*
474  * -------------------------------------------------------------------
475  * dz_tx_empty() -- get the transmitter empty status
476  *
477  * Purpose: Let user call ioctl() to get info when the UART physically
478  *          is emptied.  On bus types like RS485, the transmitter must
479  *          release the bus after transmitting. This must be done when
480  *          the transmit shift register is empty, not be done when the
481  *          transmit holding register is empty.  This functionality
482  *          allows an RS485 driver to be written in user space.
483  * -------------------------------------------------------------------
484  */
485 static unsigned int dz_tx_empty(struct uart_port *uport)
486 {
487 	struct dz_port *dport = to_dport(uport);
488 	unsigned short tmp, mask = 1 << dport->port.line;
489 
490 	tmp = dz_in(dport, DZ_TCR);
491 	tmp &= mask;
492 
493 	return tmp ? 0 : TIOCSER_TEMT;
494 }
495 
496 static void dz_break_ctl(struct uart_port *uport, int break_state)
497 {
498 	/*
499 	 * FIXME: Can't access BREAK bits in TDR easily;
500 	 * reuse the code for polled TX. --macro
501 	 */
502 	struct dz_port *dport = to_dport(uport);
503 	unsigned long flags;
504 	unsigned short tmp, mask = 1 << dport->port.line;
505 
506 	spin_lock_irqsave(&uport->lock, flags);
507 	tmp = dz_in(dport, DZ_TCR);
508 	if (break_state)
509 		tmp |= mask;
510 	else
511 		tmp &= ~mask;
512 	dz_out(dport, DZ_TCR, tmp);
513 	spin_unlock_irqrestore(&uport->lock, flags);
514 }
515 
516 static int dz_encode_baud_rate(unsigned int baud)
517 {
518 	switch (baud) {
519 	case 50:
520 		return DZ_B50;
521 	case 75:
522 		return DZ_B75;
523 	case 110:
524 		return DZ_B110;
525 	case 134:
526 		return DZ_B134;
527 	case 150:
528 		return DZ_B150;
529 	case 300:
530 		return DZ_B300;
531 	case 600:
532 		return DZ_B600;
533 	case 1200:
534 		return DZ_B1200;
535 	case 1800:
536 		return DZ_B1800;
537 	case 2000:
538 		return DZ_B2000;
539 	case 2400:
540 		return DZ_B2400;
541 	case 3600:
542 		return DZ_B3600;
543 	case 4800:
544 		return DZ_B4800;
545 	case 7200:
546 		return DZ_B7200;
547 	case 9600:
548 		return DZ_B9600;
549 	default:
550 		return -1;
551 	}
552 }
553 
554 
555 static void dz_reset(struct dz_port *dport)
556 {
557 	struct dz_mux *mux = dport->mux;
558 
559 	if (mux->initialised)
560 		return;
561 
562 	dz_out(dport, DZ_CSR, DZ_CLR);
563 	while (dz_in(dport, DZ_CSR) & DZ_CLR);
564 	iob();
565 
566 	/* Enable scanning.  */
567 	dz_out(dport, DZ_CSR, DZ_MSE);
568 
569 	mux->initialised = 1;
570 }
571 
572 static void dz_set_termios(struct uart_port *uport, struct ktermios *termios,
573 			   struct ktermios *old_termios)
574 {
575 	struct dz_port *dport = to_dport(uport);
576 	unsigned long flags;
577 	unsigned int cflag, baud;
578 	int bflag;
579 
580 	cflag = dport->port.line;
581 
582 	switch (termios->c_cflag & CSIZE) {
583 	case CS5:
584 		cflag |= DZ_CS5;
585 		break;
586 	case CS6:
587 		cflag |= DZ_CS6;
588 		break;
589 	case CS7:
590 		cflag |= DZ_CS7;
591 		break;
592 	case CS8:
593 	default:
594 		cflag |= DZ_CS8;
595 	}
596 
597 	if (termios->c_cflag & CSTOPB)
598 		cflag |= DZ_CSTOPB;
599 	if (termios->c_cflag & PARENB)
600 		cflag |= DZ_PARENB;
601 	if (termios->c_cflag & PARODD)
602 		cflag |= DZ_PARODD;
603 
604 	baud = uart_get_baud_rate(uport, termios, old_termios, 50, 9600);
605 	bflag = dz_encode_baud_rate(baud);
606 	if (bflag < 0)	{			/* Try to keep unchanged.  */
607 		baud = uart_get_baud_rate(uport, old_termios, NULL, 50, 9600);
608 		bflag = dz_encode_baud_rate(baud);
609 		if (bflag < 0)	{		/* Resort to 9600.  */
610 			baud = 9600;
611 			bflag = DZ_B9600;
612 		}
613 		tty_termios_encode_baud_rate(termios, baud, baud);
614 	}
615 	cflag |= bflag;
616 
617 	if (termios->c_cflag & CREAD)
618 		cflag |= DZ_RXENAB;
619 
620 	spin_lock_irqsave(&dport->port.lock, flags);
621 
622 	uart_update_timeout(uport, termios->c_cflag, baud);
623 
624 	dz_out(dport, DZ_LPR, cflag);
625 	dport->cflag = cflag;
626 
627 	/* setup accept flag */
628 	dport->port.read_status_mask = DZ_OERR;
629 	if (termios->c_iflag & INPCK)
630 		dport->port.read_status_mask |= DZ_FERR | DZ_PERR;
631 	if (termios->c_iflag & (BRKINT | PARMRK))
632 		dport->port.read_status_mask |= DZ_BREAK;
633 
634 	/* characters to ignore */
635 	uport->ignore_status_mask = 0;
636 	if ((termios->c_iflag & (IGNPAR | IGNBRK)) == (IGNPAR | IGNBRK))
637 		dport->port.ignore_status_mask |= DZ_OERR;
638 	if (termios->c_iflag & IGNPAR)
639 		dport->port.ignore_status_mask |= DZ_FERR | DZ_PERR;
640 	if (termios->c_iflag & IGNBRK)
641 		dport->port.ignore_status_mask |= DZ_BREAK;
642 
643 	spin_unlock_irqrestore(&dport->port.lock, flags);
644 }
645 
646 /*
647  * Hack alert!
648  * Required solely so that the initial PROM-based console
649  * works undisturbed in parallel with this one.
650  */
651 static void dz_pm(struct uart_port *uport, unsigned int state,
652 		  unsigned int oldstate)
653 {
654 	struct dz_port *dport = to_dport(uport);
655 	unsigned long flags;
656 
657 	spin_lock_irqsave(&dport->port.lock, flags);
658 	if (state < 3)
659 		dz_start_tx(&dport->port);
660 	else
661 		dz_stop_tx(&dport->port);
662 	spin_unlock_irqrestore(&dport->port.lock, flags);
663 }
664 
665 
666 static const char *dz_type(struct uart_port *uport)
667 {
668 	return "DZ";
669 }
670 
671 static void dz_release_port(struct uart_port *uport)
672 {
673 	struct dz_mux *mux = to_dport(uport)->mux;
674 	int map_guard;
675 
676 	iounmap(uport->membase);
677 	uport->membase = NULL;
678 
679 	map_guard = atomic_add_return(-1, &mux->map_guard);
680 	if (!map_guard)
681 		release_mem_region(uport->mapbase, dec_kn_slot_size);
682 }
683 
684 static int dz_map_port(struct uart_port *uport)
685 {
686 	if (!uport->membase)
687 		uport->membase = ioremap_nocache(uport->mapbase,
688 						 dec_kn_slot_size);
689 	if (!uport->membase) {
690 		printk(KERN_ERR "dz: Cannot map MMIO\n");
691 		return -ENOMEM;
692 	}
693 	return 0;
694 }
695 
696 static int dz_request_port(struct uart_port *uport)
697 {
698 	struct dz_mux *mux = to_dport(uport)->mux;
699 	int map_guard;
700 	int ret;
701 
702 	map_guard = atomic_add_return(1, &mux->map_guard);
703 	if (map_guard == 1) {
704 		if (!request_mem_region(uport->mapbase, dec_kn_slot_size,
705 					"dz")) {
706 			atomic_add(-1, &mux->map_guard);
707 			printk(KERN_ERR
708 			       "dz: Unable to reserve MMIO resource\n");
709 			return -EBUSY;
710 		}
711 	}
712 	ret = dz_map_port(uport);
713 	if (ret) {
714 		map_guard = atomic_add_return(-1, &mux->map_guard);
715 		if (!map_guard)
716 			release_mem_region(uport->mapbase, dec_kn_slot_size);
717 		return ret;
718 	}
719 	return 0;
720 }
721 
722 static void dz_config_port(struct uart_port *uport, int flags)
723 {
724 	struct dz_port *dport = to_dport(uport);
725 
726 	if (flags & UART_CONFIG_TYPE) {
727 		if (dz_request_port(uport))
728 			return;
729 
730 		uport->type = PORT_DZ;
731 
732 		dz_reset(dport);
733 	}
734 }
735 
736 /*
737  * Verify the new serial_struct (for TIOCSSERIAL).
738  */
739 static int dz_verify_port(struct uart_port *uport, struct serial_struct *ser)
740 {
741 	int ret = 0;
742 
743 	if (ser->type != PORT_UNKNOWN && ser->type != PORT_DZ)
744 		ret = -EINVAL;
745 	if (ser->irq != uport->irq)
746 		ret = -EINVAL;
747 	return ret;
748 }
749 
750 static struct uart_ops dz_ops = {
751 	.tx_empty	= dz_tx_empty,
752 	.get_mctrl	= dz_get_mctrl,
753 	.set_mctrl	= dz_set_mctrl,
754 	.stop_tx	= dz_stop_tx,
755 	.start_tx	= dz_start_tx,
756 	.stop_rx	= dz_stop_rx,
757 	.enable_ms	= dz_enable_ms,
758 	.break_ctl	= dz_break_ctl,
759 	.startup	= dz_startup,
760 	.shutdown	= dz_shutdown,
761 	.set_termios	= dz_set_termios,
762 	.pm		= dz_pm,
763 	.type		= dz_type,
764 	.release_port	= dz_release_port,
765 	.request_port	= dz_request_port,
766 	.config_port	= dz_config_port,
767 	.verify_port	= dz_verify_port,
768 };
769 
770 static void __init dz_init_ports(void)
771 {
772 	static int first = 1;
773 	unsigned long base;
774 	int line;
775 
776 	if (!first)
777 		return;
778 	first = 0;
779 
780 	if (mips_machtype == MACH_DS23100 || mips_machtype == MACH_DS5100)
781 		base = dec_kn_slot_base + KN01_DZ11;
782 	else
783 		base = dec_kn_slot_base + KN02_DZ11;
784 
785 	for (line = 0; line < DZ_NB_PORT; line++) {
786 		struct dz_port *dport = &dz_mux.dport[line];
787 		struct uart_port *uport = &dport->port;
788 
789 		dport->mux	= &dz_mux;
790 
791 		uport->irq	= dec_interrupt[DEC_IRQ_DZ11];
792 		uport->fifosize	= 1;
793 		uport->iotype	= UPIO_MEM;
794 		uport->flags	= UPF_BOOT_AUTOCONF;
795 		uport->ops	= &dz_ops;
796 		uport->line	= line;
797 		uport->mapbase	= base;
798 	}
799 }
800 
801 #ifdef CONFIG_SERIAL_DZ_CONSOLE
802 /*
803  * -------------------------------------------------------------------
804  * dz_console_putchar() -- transmit a character
805  *
806  * Polled transmission.  This is tricky.  We need to mask transmit
807  * interrupts so that they do not interfere, enable the transmitter
808  * for the line requested and then wait till the transmit scanner
809  * requests data for this line.  But it may request data for another
810  * line first, in which case we have to disable its transmitter and
811  * repeat waiting till our line pops up.  Only then the character may
812  * be transmitted.  Finally, the state of the transmitter mask is
813  * restored.  Welcome to the world of PDP-11!
814  * -------------------------------------------------------------------
815  */
816 static void dz_console_putchar(struct uart_port *uport, int ch)
817 {
818 	struct dz_port *dport = to_dport(uport);
819 	unsigned long flags;
820 	unsigned short csr, tcr, trdy, mask;
821 	int loops = 10000;
822 
823 	spin_lock_irqsave(&dport->port.lock, flags);
824 	csr = dz_in(dport, DZ_CSR);
825 	dz_out(dport, DZ_CSR, csr & ~DZ_TIE);
826 	tcr = dz_in(dport, DZ_TCR);
827 	tcr |= 1 << dport->port.line;
828 	mask = tcr;
829 	dz_out(dport, DZ_TCR, mask);
830 	iob();
831 	spin_unlock_irqrestore(&dport->port.lock, flags);
832 
833 	do {
834 		trdy = dz_in(dport, DZ_CSR);
835 		if (!(trdy & DZ_TRDY))
836 			continue;
837 		trdy = (trdy & DZ_TLINE) >> 8;
838 		if (trdy == dport->port.line)
839 			break;
840 		mask &= ~(1 << trdy);
841 		dz_out(dport, DZ_TCR, mask);
842 		iob();
843 		udelay(2);
844 	} while (--loops);
845 
846 	if (loops)				/* Cannot send otherwise. */
847 		dz_out(dport, DZ_TDR, ch);
848 
849 	dz_out(dport, DZ_TCR, tcr);
850 	dz_out(dport, DZ_CSR, csr);
851 }
852 
853 /*
854  * -------------------------------------------------------------------
855  * dz_console_print ()
856  *
857  * dz_console_print is registered for printk.
858  * The console must be locked when we get here.
859  * -------------------------------------------------------------------
860  */
861 static void dz_console_print(struct console *co,
862 			     const char *str,
863 			     unsigned int count)
864 {
865 	struct dz_port *dport = &dz_mux.dport[co->index];
866 #ifdef DEBUG_DZ
867 	prom_printf((char *) str);
868 #endif
869 	uart_console_write(&dport->port, str, count, dz_console_putchar);
870 }
871 
872 static int __init dz_console_setup(struct console *co, char *options)
873 {
874 	struct dz_port *dport = &dz_mux.dport[co->index];
875 	struct uart_port *uport = &dport->port;
876 	int baud = 9600;
877 	int bits = 8;
878 	int parity = 'n';
879 	int flow = 'n';
880 	int ret;
881 
882 	ret = dz_map_port(uport);
883 	if (ret)
884 		return ret;
885 
886 	spin_lock_init(&dport->port.lock);	/* For dz_pm().  */
887 
888 	dz_reset(dport);
889 	dz_pm(uport, 0, -1);
890 
891 	if (options)
892 		uart_parse_options(options, &baud, &parity, &bits, &flow);
893 
894 	return uart_set_options(&dport->port, co, baud, parity, bits, flow);
895 }
896 
897 static struct uart_driver dz_reg;
898 static struct console dz_console = {
899 	.name	= "ttyS",
900 	.write	= dz_console_print,
901 	.device	= uart_console_device,
902 	.setup	= dz_console_setup,
903 	.flags	= CON_PRINTBUFFER,
904 	.index	= -1,
905 	.data	= &dz_reg,
906 };
907 
908 static int __init dz_serial_console_init(void)
909 {
910 	if (!IOASIC) {
911 		dz_init_ports();
912 		register_console(&dz_console);
913 		return 0;
914 	} else
915 		return -ENXIO;
916 }
917 
918 console_initcall(dz_serial_console_init);
919 
920 #define SERIAL_DZ_CONSOLE	&dz_console
921 #else
922 #define SERIAL_DZ_CONSOLE	NULL
923 #endif /* CONFIG_SERIAL_DZ_CONSOLE */
924 
925 static struct uart_driver dz_reg = {
926 	.owner			= THIS_MODULE,
927 	.driver_name		= "serial",
928 	.dev_name		= "ttyS",
929 	.major			= TTY_MAJOR,
930 	.minor			= 64,
931 	.nr			= DZ_NB_PORT,
932 	.cons			= SERIAL_DZ_CONSOLE,
933 };
934 
935 static int __init dz_init(void)
936 {
937 	int ret, i;
938 
939 	if (IOASIC)
940 		return -ENXIO;
941 
942 	printk("%s%s\n", dz_name, dz_version);
943 
944 	dz_init_ports();
945 
946 	ret = uart_register_driver(&dz_reg);
947 	if (ret)
948 		return ret;
949 
950 	for (i = 0; i < DZ_NB_PORT; i++)
951 		uart_add_one_port(&dz_reg, &dz_mux.dport[i].port);
952 
953 	return 0;
954 }
955 
956 module_init(dz_init);
957