xref: /linux/drivers/tty/amiserial.c (revision 4e0ae876f77bc01a7e77724dea57b4b82bd53244)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Serial driver for the amiga builtin port.
4  *
5  * This code was created by taking serial.c version 4.30 from kernel
6  * release 2.3.22, replacing all hardware related stuff with the
7  * corresponding amiga hardware actions, and removing all irrelevant
8  * code. As a consequence, it uses many of the constants and names
9  * associated with the registers and bits of 16550 compatible UARTS -
10  * but only to keep track of status, etc in the state variables. It
11  * was done this was to make it easier to keep the code in line with
12  * (non hardware specific) changes to serial.c.
13  *
14  * The port is registered with the tty driver as minor device 64, and
15  * therefore other ports should should only use 65 upwards.
16  *
17  * Richard Lucock 28/12/99
18  *
19  *  Copyright (C) 1991, 1992  Linus Torvalds
20  *  Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997,
21  * 		1998, 1999  Theodore Ts'o
22  *
23  */
24 
25 /*
26  * Serial driver configuration section.  Here are the various options:
27  *
28  * SERIAL_PARANOIA_CHECK
29  * 		Check the magic number for the async_structure where
30  * 		ever possible.
31  */
32 
33 #include <linux/delay.h>
34 
35 #undef SERIAL_PARANOIA_CHECK
36 
37 /* Set of debugging defines */
38 
39 #undef SERIAL_DEBUG_INTR
40 #undef SERIAL_DEBUG_OPEN
41 #undef SERIAL_DEBUG_FLOW
42 #undef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
43 
44 /* Sanity checks */
45 
46 #if defined(MODULE) && defined(SERIAL_DEBUG_MCOUNT)
47 #define DBG_CNT(s) printk("(%s): [%x] refc=%d, serc=%d, ttyc=%d -> %s\n", \
48  tty->name, (info->tport.flags), serial_driver->refcount,info->count,tty->count,s)
49 #else
50 #define DBG_CNT(s)
51 #endif
52 
53 /*
54  * End of serial driver configuration section.
55  */
56 
57 #include <linux/module.h>
58 
59 #include <linux/types.h>
60 #include <linux/serial.h>
61 #include <linux/serial_reg.h>
62 static char *serial_version = "4.30";
63 
64 #include <linux/errno.h>
65 #include <linux/signal.h>
66 #include <linux/sched.h>
67 #include <linux/kernel.h>
68 #include <linux/timer.h>
69 #include <linux/interrupt.h>
70 #include <linux/tty.h>
71 #include <linux/tty_flip.h>
72 #include <linux/circ_buf.h>
73 #include <linux/console.h>
74 #include <linux/major.h>
75 #include <linux/string.h>
76 #include <linux/fcntl.h>
77 #include <linux/ptrace.h>
78 #include <linux/ioport.h>
79 #include <linux/mm.h>
80 #include <linux/seq_file.h>
81 #include <linux/slab.h>
82 #include <linux/init.h>
83 #include <linux/bitops.h>
84 #include <linux/platform_device.h>
85 
86 #include <asm/setup.h>
87 
88 
89 #include <asm/irq.h>
90 
91 #include <asm/amigahw.h>
92 #include <asm/amigaints.h>
93 
94 struct serial_state {
95 	struct tty_port		tport;
96 	struct circ_buf		xmit;
97 	struct async_icount	icount;
98 
99 	unsigned long		port;
100 	int			baud_base;
101 	int			xmit_fifo_size;
102 	int			custom_divisor;
103 	int			read_status_mask;
104 	int			ignore_status_mask;
105 	int			timeout;
106 	int			quot;
107 	int			IER; 	/* Interrupt Enable Register */
108 	int			MCR; 	/* Modem control register */
109 	int			x_char;	/* xon/xoff character */
110 };
111 
112 #define custom amiga_custom
113 static char *serial_name = "Amiga-builtin serial driver";
114 
115 static struct tty_driver *serial_driver;
116 
117 /* number of characters left in xmit buffer before we ask for more */
118 #define WAKEUP_CHARS 256
119 
120 static unsigned char current_ctl_bits;
121 
122 static void change_speed(struct tty_struct *tty, struct serial_state *info,
123 		struct ktermios *old);
124 static void rs_wait_until_sent(struct tty_struct *tty, int timeout);
125 
126 
127 static struct serial_state rs_table[1];
128 
129 #define NR_PORTS ARRAY_SIZE(rs_table)
130 
131 #include <linux/uaccess.h>
132 
133 #define serial_isroot()	(capable(CAP_SYS_ADMIN))
134 
135 
136 static inline int serial_paranoia_check(struct serial_state *info,
137 					char *name, const char *routine)
138 {
139 #ifdef SERIAL_PARANOIA_CHECK
140 	static const char *badmagic =
141 		"Warning: bad magic number for serial struct (%s) in %s\n";
142 	static const char *badinfo =
143 		"Warning: null async_struct for (%s) in %s\n";
144 
145 	if (!info) {
146 		printk(badinfo, name, routine);
147 		return 1;
148 	}
149 	if (info->magic != SERIAL_MAGIC) {
150 		printk(badmagic, name, routine);
151 		return 1;
152 	}
153 #endif
154 	return 0;
155 }
156 
157 /* some serial hardware definitions */
158 #define SDR_OVRUN   (1<<15)
159 #define SDR_RBF     (1<<14)
160 #define SDR_TBE     (1<<13)
161 #define SDR_TSRE    (1<<12)
162 
163 #define SERPER_PARENB    (1<<15)
164 
165 #define AC_SETCLR   (1<<15)
166 #define AC_UARTBRK  (1<<11)
167 
168 #define SER_DTR     (1<<7)
169 #define SER_RTS     (1<<6)
170 #define SER_DCD     (1<<5)
171 #define SER_CTS     (1<<4)
172 #define SER_DSR     (1<<3)
173 
174 static __inline__ void rtsdtr_ctrl(int bits)
175 {
176     ciab.pra = ((bits & (SER_RTS | SER_DTR)) ^ (SER_RTS | SER_DTR)) | (ciab.pra & ~(SER_RTS | SER_DTR));
177 }
178 
179 /*
180  * ------------------------------------------------------------
181  * rs_stop() and rs_start()
182  *
183  * This routines are called before setting or resetting tty->stopped.
184  * They enable or disable transmitter interrupts, as necessary.
185  * ------------------------------------------------------------
186  */
187 static void rs_stop(struct tty_struct *tty)
188 {
189 	struct serial_state *info = tty->driver_data;
190 	unsigned long flags;
191 
192 	if (serial_paranoia_check(info, tty->name, "rs_stop"))
193 		return;
194 
195 	local_irq_save(flags);
196 	if (info->IER & UART_IER_THRI) {
197 		info->IER &= ~UART_IER_THRI;
198 		/* disable Tx interrupt and remove any pending interrupts */
199 		custom.intena = IF_TBE;
200 		mb();
201 		custom.intreq = IF_TBE;
202 		mb();
203 	}
204 	local_irq_restore(flags);
205 }
206 
207 static void rs_start(struct tty_struct *tty)
208 {
209 	struct serial_state *info = tty->driver_data;
210 	unsigned long flags;
211 
212 	if (serial_paranoia_check(info, tty->name, "rs_start"))
213 		return;
214 
215 	local_irq_save(flags);
216 	if (info->xmit.head != info->xmit.tail
217 	    && info->xmit.buf
218 	    && !(info->IER & UART_IER_THRI)) {
219 		info->IER |= UART_IER_THRI;
220 		custom.intena = IF_SETCLR | IF_TBE;
221 		mb();
222 		/* set a pending Tx Interrupt, transmitter should restart now */
223 		custom.intreq = IF_SETCLR | IF_TBE;
224 		mb();
225 	}
226 	local_irq_restore(flags);
227 }
228 
229 /*
230  * ----------------------------------------------------------------------
231  *
232  * Here starts the interrupt handling routines.  All of the following
233  * subroutines are declared as inline and are folded into
234  * rs_interrupt().  They were separated out for readability's sake.
235  *
236  * Note: rs_interrupt() is a "fast" interrupt, which means that it
237  * runs with interrupts turned off.  People who may want to modify
238  * rs_interrupt() should try to keep the interrupt handler as fast as
239  * possible.  After you are done making modifications, it is not a bad
240  * idea to do:
241  *
242  * gcc -S -DKERNEL -Wall -Wstrict-prototypes -O6 -fomit-frame-pointer serial.c
243  *
244  * and look at the resulting assemble code in serial.s.
245  *
246  * 				- Ted Ts'o (tytso@mit.edu), 7-Mar-93
247  * -----------------------------------------------------------------------
248  */
249 
250 static void receive_chars(struct serial_state *info)
251 {
252         int status;
253 	int serdatr;
254 	unsigned char ch, flag;
255 	struct	async_icount *icount;
256 	int oe = 0;
257 
258 	icount = &info->icount;
259 
260 	status = UART_LSR_DR; /* We obviously have a character! */
261 	serdatr = custom.serdatr;
262 	mb();
263 	custom.intreq = IF_RBF;
264 	mb();
265 
266 	if((serdatr & 0x1ff) == 0)
267 	    status |= UART_LSR_BI;
268 	if(serdatr & SDR_OVRUN)
269 	    status |= UART_LSR_OE;
270 
271 	ch = serdatr & 0xff;
272 	icount->rx++;
273 
274 #ifdef SERIAL_DEBUG_INTR
275 	printk("DR%02x:%02x...", ch, status);
276 #endif
277 	flag = TTY_NORMAL;
278 
279 	/*
280 	 * We don't handle parity or frame errors - but I have left
281 	 * the code in, since I'm not sure that the errors can't be
282 	 * detected.
283 	 */
284 
285 	if (status & (UART_LSR_BI | UART_LSR_PE |
286 		      UART_LSR_FE | UART_LSR_OE)) {
287 	  /*
288 	   * For statistics only
289 	   */
290 	  if (status & UART_LSR_BI) {
291 	    status &= ~(UART_LSR_FE | UART_LSR_PE);
292 	    icount->brk++;
293 	  } else if (status & UART_LSR_PE)
294 	    icount->parity++;
295 	  else if (status & UART_LSR_FE)
296 	    icount->frame++;
297 	  if (status & UART_LSR_OE)
298 	    icount->overrun++;
299 
300 	  /*
301 	   * Now check to see if character should be
302 	   * ignored, and mask off conditions which
303 	   * should be ignored.
304 	   */
305 	  if (status & info->ignore_status_mask)
306 	    goto out;
307 
308 	  status &= info->read_status_mask;
309 
310 	  if (status & (UART_LSR_BI)) {
311 #ifdef SERIAL_DEBUG_INTR
312 	    printk("handling break....");
313 #endif
314 	    flag = TTY_BREAK;
315 	    if (info->tport.flags & ASYNC_SAK)
316 	      do_SAK(info->tport.tty);
317 	  } else if (status & UART_LSR_PE)
318 	    flag = TTY_PARITY;
319 	  else if (status & UART_LSR_FE)
320 	    flag = TTY_FRAME;
321 	  if (status & UART_LSR_OE) {
322 	    /*
323 	     * Overrun is special, since it's
324 	     * reported immediately, and doesn't
325 	     * affect the current character
326 	     */
327 	     oe = 1;
328 	  }
329 	}
330 	tty_insert_flip_char(&info->tport, ch, flag);
331 	if (oe == 1)
332 		tty_insert_flip_char(&info->tport, 0, TTY_OVERRUN);
333 	tty_flip_buffer_push(&info->tport);
334 out:
335 	return;
336 }
337 
338 static void transmit_chars(struct serial_state *info)
339 {
340 	custom.intreq = IF_TBE;
341 	mb();
342 	if (info->x_char) {
343 	        custom.serdat = info->x_char | 0x100;
344 		mb();
345 		info->icount.tx++;
346 		info->x_char = 0;
347 		return;
348 	}
349 	if (info->xmit.head == info->xmit.tail
350 	    || info->tport.tty->stopped
351 	    || info->tport.tty->hw_stopped) {
352 		info->IER &= ~UART_IER_THRI;
353 	        custom.intena = IF_TBE;
354 		mb();
355 		return;
356 	}
357 
358 	custom.serdat = info->xmit.buf[info->xmit.tail++] | 0x100;
359 	mb();
360 	info->xmit.tail = info->xmit.tail & (SERIAL_XMIT_SIZE-1);
361 	info->icount.tx++;
362 
363 	if (CIRC_CNT(info->xmit.head,
364 		     info->xmit.tail,
365 		     SERIAL_XMIT_SIZE) < WAKEUP_CHARS)
366 		tty_wakeup(info->tport.tty);
367 
368 #ifdef SERIAL_DEBUG_INTR
369 	printk("THRE...");
370 #endif
371 	if (info->xmit.head == info->xmit.tail) {
372 	        custom.intena = IF_TBE;
373 		mb();
374 		info->IER &= ~UART_IER_THRI;
375 	}
376 }
377 
378 static void check_modem_status(struct serial_state *info)
379 {
380 	struct tty_port *port = &info->tport;
381 	unsigned char status = ciab.pra & (SER_DCD | SER_CTS | SER_DSR);
382 	unsigned char dstatus;
383 	struct	async_icount *icount;
384 
385 	/* Determine bits that have changed */
386 	dstatus = status ^ current_ctl_bits;
387 	current_ctl_bits = status;
388 
389 	if (dstatus) {
390 		icount = &info->icount;
391 		/* update input line counters */
392 		if (dstatus & SER_DSR)
393 			icount->dsr++;
394 		if (dstatus & SER_DCD) {
395 			icount->dcd++;
396 		}
397 		if (dstatus & SER_CTS)
398 			icount->cts++;
399 		wake_up_interruptible(&port->delta_msr_wait);
400 	}
401 
402 	if (tty_port_check_carrier(port) && (dstatus & SER_DCD)) {
403 #if (defined(SERIAL_DEBUG_OPEN) || defined(SERIAL_DEBUG_INTR))
404 		printk("ttyS%d CD now %s...", info->line,
405 		       (!(status & SER_DCD)) ? "on" : "off");
406 #endif
407 		if (!(status & SER_DCD))
408 			wake_up_interruptible(&port->open_wait);
409 		else {
410 #ifdef SERIAL_DEBUG_OPEN
411 			printk("doing serial hangup...");
412 #endif
413 			if (port->tty)
414 				tty_hangup(port->tty);
415 		}
416 	}
417 	if (tty_port_cts_enabled(port)) {
418 		if (port->tty->hw_stopped) {
419 			if (!(status & SER_CTS)) {
420 #if (defined(SERIAL_DEBUG_INTR) || defined(SERIAL_DEBUG_FLOW))
421 				printk("CTS tx start...");
422 #endif
423 				port->tty->hw_stopped = 0;
424 				info->IER |= UART_IER_THRI;
425 				custom.intena = IF_SETCLR | IF_TBE;
426 				mb();
427 				/* set a pending Tx Interrupt, transmitter should restart now */
428 				custom.intreq = IF_SETCLR | IF_TBE;
429 				mb();
430 				tty_wakeup(port->tty);
431 				return;
432 			}
433 		} else {
434 			if ((status & SER_CTS)) {
435 #if (defined(SERIAL_DEBUG_INTR) || defined(SERIAL_DEBUG_FLOW))
436 				printk("CTS tx stop...");
437 #endif
438 				port->tty->hw_stopped = 1;
439 				info->IER &= ~UART_IER_THRI;
440 				/* disable Tx interrupt and remove any pending interrupts */
441 				custom.intena = IF_TBE;
442 				mb();
443 				custom.intreq = IF_TBE;
444 				mb();
445 			}
446 		}
447 	}
448 }
449 
450 static irqreturn_t ser_vbl_int( int irq, void *data)
451 {
452         /* vbl is just a periodic interrupt we tie into to update modem status */
453 	struct serial_state *info = data;
454 	/*
455 	 * TBD - is it better to unregister from this interrupt or to
456 	 * ignore it if MSI is clear ?
457 	 */
458 	if(info->IER & UART_IER_MSI)
459 	  check_modem_status(info);
460 	return IRQ_HANDLED;
461 }
462 
463 static irqreturn_t ser_rx_int(int irq, void *dev_id)
464 {
465 	struct serial_state *info = dev_id;
466 
467 #ifdef SERIAL_DEBUG_INTR
468 	printk("ser_rx_int...");
469 #endif
470 
471 	if (!info->tport.tty)
472 		return IRQ_NONE;
473 
474 	receive_chars(info);
475 #ifdef SERIAL_DEBUG_INTR
476 	printk("end.\n");
477 #endif
478 	return IRQ_HANDLED;
479 }
480 
481 static irqreturn_t ser_tx_int(int irq, void *dev_id)
482 {
483 	struct serial_state *info = dev_id;
484 
485 	if (custom.serdatr & SDR_TBE) {
486 #ifdef SERIAL_DEBUG_INTR
487 	  printk("ser_tx_int...");
488 #endif
489 
490 	  if (!info->tport.tty)
491 		return IRQ_NONE;
492 
493 	  transmit_chars(info);
494 #ifdef SERIAL_DEBUG_INTR
495 	  printk("end.\n");
496 #endif
497 	}
498 	return IRQ_HANDLED;
499 }
500 
501 /*
502  * -------------------------------------------------------------------
503  * Here ends the serial interrupt routines.
504  * -------------------------------------------------------------------
505  */
506 
507 /*
508  * ---------------------------------------------------------------
509  * Low level utility subroutines for the serial driver:  routines to
510  * figure out the appropriate timeout for an interrupt chain, routines
511  * to initialize and startup a serial port, and routines to shutdown a
512  * serial port.  Useful stuff like that.
513  * ---------------------------------------------------------------
514  */
515 
516 static int startup(struct tty_struct *tty, struct serial_state *info)
517 {
518 	struct tty_port *port = &info->tport;
519 	unsigned long flags;
520 	int	retval=0;
521 	unsigned long page;
522 
523 	page = get_zeroed_page(GFP_KERNEL);
524 	if (!page)
525 		return -ENOMEM;
526 
527 	local_irq_save(flags);
528 
529 	if (tty_port_initialized(port)) {
530 		free_page(page);
531 		goto errout;
532 	}
533 
534 	if (info->xmit.buf)
535 		free_page(page);
536 	else
537 		info->xmit.buf = (unsigned char *) page;
538 
539 #ifdef SERIAL_DEBUG_OPEN
540 	printk("starting up ttys%d ...", info->line);
541 #endif
542 
543 	/* Clear anything in the input buffer */
544 
545 	custom.intreq = IF_RBF;
546 	mb();
547 
548 	retval = request_irq(IRQ_AMIGA_VERTB, ser_vbl_int, 0, "serial status", info);
549 	if (retval) {
550 	  if (serial_isroot()) {
551 	      set_bit(TTY_IO_ERROR, &tty->flags);
552 	    retval = 0;
553 	  }
554 	  goto errout;
555 	}
556 
557 	/* enable both Rx and Tx interrupts */
558 	custom.intena = IF_SETCLR | IF_RBF | IF_TBE;
559 	mb();
560 	info->IER = UART_IER_MSI;
561 
562 	/* remember current state of the DCD and CTS bits */
563 	current_ctl_bits = ciab.pra & (SER_DCD | SER_CTS | SER_DSR);
564 
565 	info->MCR = 0;
566 	if (C_BAUD(tty))
567 	  info->MCR = SER_DTR | SER_RTS;
568 	rtsdtr_ctrl(info->MCR);
569 
570 	clear_bit(TTY_IO_ERROR, &tty->flags);
571 	info->xmit.head = info->xmit.tail = 0;
572 
573 	/*
574 	 * and set the speed of the serial port
575 	 */
576 	change_speed(tty, info, NULL);
577 
578 	tty_port_set_initialized(port, 1);
579 	local_irq_restore(flags);
580 	return 0;
581 
582 errout:
583 	local_irq_restore(flags);
584 	return retval;
585 }
586 
587 /*
588  * This routine will shutdown a serial port; interrupts are disabled, and
589  * DTR is dropped if the hangup on close termio flag is on.
590  */
591 static void shutdown(struct tty_struct *tty, struct serial_state *info)
592 {
593 	unsigned long	flags;
594 	struct serial_state *state;
595 
596 	if (!tty_port_initialized(&info->tport))
597 		return;
598 
599 	state = info;
600 
601 #ifdef SERIAL_DEBUG_OPEN
602 	printk("Shutting down serial port %d ....\n", info->line);
603 #endif
604 
605 	local_irq_save(flags); /* Disable interrupts */
606 
607 	/*
608 	 * clear delta_msr_wait queue to avoid mem leaks: we may free the irq
609 	 * here so the queue might never be waken up
610 	 */
611 	wake_up_interruptible(&info->tport.delta_msr_wait);
612 
613 	/*
614 	 * Free the IRQ, if necessary
615 	 */
616 	free_irq(IRQ_AMIGA_VERTB, info);
617 
618 	if (info->xmit.buf) {
619 		free_page((unsigned long) info->xmit.buf);
620 		info->xmit.buf = NULL;
621 	}
622 
623 	info->IER = 0;
624 	custom.intena = IF_RBF | IF_TBE;
625 	mb();
626 
627 	/* disable break condition */
628 	custom.adkcon = AC_UARTBRK;
629 	mb();
630 
631 	if (C_HUPCL(tty))
632 		info->MCR &= ~(SER_DTR|SER_RTS);
633 	rtsdtr_ctrl(info->MCR);
634 
635 	set_bit(TTY_IO_ERROR, &tty->flags);
636 
637 	tty_port_set_initialized(&info->tport, 0);
638 	local_irq_restore(flags);
639 }
640 
641 
642 /*
643  * This routine is called to set the UART divisor registers to match
644  * the specified baud rate for a serial port.
645  */
646 static void change_speed(struct tty_struct *tty, struct serial_state *info,
647 			 struct ktermios *old_termios)
648 {
649 	struct tty_port *port = &info->tport;
650 	int	quot = 0, baud_base, baud;
651 	unsigned cflag, cval = 0;
652 	int	bits;
653 	unsigned long	flags;
654 
655 	cflag = tty->termios.c_cflag;
656 
657 	/* Byte size is always 8 bits plus parity bit if requested */
658 
659 	cval = 3; bits = 10;
660 	if (cflag & CSTOPB) {
661 		cval |= 0x04;
662 		bits++;
663 	}
664 	if (cflag & PARENB) {
665 		cval |= UART_LCR_PARITY;
666 		bits++;
667 	}
668 	if (!(cflag & PARODD))
669 		cval |= UART_LCR_EPAR;
670 #ifdef CMSPAR
671 	if (cflag & CMSPAR)
672 		cval |= UART_LCR_SPAR;
673 #endif
674 
675 	/* Determine divisor based on baud rate */
676 	baud = tty_get_baud_rate(tty);
677 	if (!baud)
678 		baud = 9600;	/* B0 transition handled in rs_set_termios */
679 	baud_base = info->baud_base;
680 	if (baud == 38400 && (port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST)
681 		quot = info->custom_divisor;
682 	else {
683 		if (baud == 134)
684 			/* Special case since 134 is really 134.5 */
685 			quot = (2*baud_base / 269);
686 		else if (baud)
687 			quot = baud_base / baud;
688 	}
689 	/* If the quotient is zero refuse the change */
690 	if (!quot && old_termios) {
691 		/* FIXME: Will need updating for new tty in the end */
692 		tty->termios.c_cflag &= ~CBAUD;
693 		tty->termios.c_cflag |= (old_termios->c_cflag & CBAUD);
694 		baud = tty_get_baud_rate(tty);
695 		if (!baud)
696 			baud = 9600;
697 		if (baud == 38400 &&
698 		    (port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST)
699 			quot = info->custom_divisor;
700 		else {
701 			if (baud == 134)
702 				/* Special case since 134 is really 134.5 */
703 				quot = (2*baud_base / 269);
704 			else if (baud)
705 				quot = baud_base / baud;
706 		}
707 	}
708 	/* As a last resort, if the quotient is zero, default to 9600 bps */
709 	if (!quot)
710 		quot = baud_base / 9600;
711 	info->quot = quot;
712 	info->timeout = ((info->xmit_fifo_size*HZ*bits*quot) / baud_base);
713 	info->timeout += HZ/50;		/* Add .02 seconds of slop */
714 
715 	/* CTS flow control flag and modem status interrupts */
716 	info->IER &= ~UART_IER_MSI;
717 	if (port->flags & ASYNC_HARDPPS_CD)
718 		info->IER |= UART_IER_MSI;
719 	tty_port_set_cts_flow(port, cflag & CRTSCTS);
720 	if (cflag & CRTSCTS)
721 		info->IER |= UART_IER_MSI;
722 	tty_port_set_check_carrier(port, ~cflag & CLOCAL);
723 	if (~cflag & CLOCAL)
724 		info->IER |= UART_IER_MSI;
725 	/* TBD:
726 	 * Does clearing IER_MSI imply that we should disable the VBL interrupt ?
727 	 */
728 
729 	/*
730 	 * Set up parity check flag
731 	 */
732 
733 	info->read_status_mask = UART_LSR_OE | UART_LSR_DR;
734 	if (I_INPCK(tty))
735 		info->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
736 	if (I_BRKINT(tty) || I_PARMRK(tty))
737 		info->read_status_mask |= UART_LSR_BI;
738 
739 	/*
740 	 * Characters to ignore
741 	 */
742 	info->ignore_status_mask = 0;
743 	if (I_IGNPAR(tty))
744 		info->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
745 	if (I_IGNBRK(tty)) {
746 		info->ignore_status_mask |= UART_LSR_BI;
747 		/*
748 		 * If we're ignore parity and break indicators, ignore
749 		 * overruns too.  (For real raw support).
750 		 */
751 		if (I_IGNPAR(tty))
752 			info->ignore_status_mask |= UART_LSR_OE;
753 	}
754 	/*
755 	 * !!! ignore all characters if CREAD is not set
756 	 */
757 	if ((cflag & CREAD) == 0)
758 		info->ignore_status_mask |= UART_LSR_DR;
759 	local_irq_save(flags);
760 
761 	{
762 	  short serper;
763 
764 	/* Set up the baud rate */
765 	  serper = quot - 1;
766 
767 	/* Enable or disable parity bit */
768 
769 	if(cval & UART_LCR_PARITY)
770 	  serper |= (SERPER_PARENB);
771 
772 	custom.serper = serper;
773 	mb();
774 	}
775 
776 	local_irq_restore(flags);
777 }
778 
779 static int rs_put_char(struct tty_struct *tty, unsigned char ch)
780 {
781 	struct serial_state *info;
782 	unsigned long flags;
783 
784 	info = tty->driver_data;
785 
786 	if (serial_paranoia_check(info, tty->name, "rs_put_char"))
787 		return 0;
788 
789 	if (!info->xmit.buf)
790 		return 0;
791 
792 	local_irq_save(flags);
793 	if (CIRC_SPACE(info->xmit.head,
794 		       info->xmit.tail,
795 		       SERIAL_XMIT_SIZE) == 0) {
796 		local_irq_restore(flags);
797 		return 0;
798 	}
799 
800 	info->xmit.buf[info->xmit.head++] = ch;
801 	info->xmit.head &= SERIAL_XMIT_SIZE-1;
802 	local_irq_restore(flags);
803 	return 1;
804 }
805 
806 static void rs_flush_chars(struct tty_struct *tty)
807 {
808 	struct serial_state *info = tty->driver_data;
809 	unsigned long flags;
810 
811 	if (serial_paranoia_check(info, tty->name, "rs_flush_chars"))
812 		return;
813 
814 	if (info->xmit.head == info->xmit.tail
815 	    || tty->stopped
816 	    || tty->hw_stopped
817 	    || !info->xmit.buf)
818 		return;
819 
820 	local_irq_save(flags);
821 	info->IER |= UART_IER_THRI;
822 	custom.intena = IF_SETCLR | IF_TBE;
823 	mb();
824 	/* set a pending Tx Interrupt, transmitter should restart now */
825 	custom.intreq = IF_SETCLR | IF_TBE;
826 	mb();
827 	local_irq_restore(flags);
828 }
829 
830 static int rs_write(struct tty_struct * tty, const unsigned char *buf, int count)
831 {
832 	int	c, ret = 0;
833 	struct serial_state *info = tty->driver_data;
834 	unsigned long flags;
835 
836 	if (serial_paranoia_check(info, tty->name, "rs_write"))
837 		return 0;
838 
839 	if (!info->xmit.buf)
840 		return 0;
841 
842 	local_irq_save(flags);
843 	while (1) {
844 		c = CIRC_SPACE_TO_END(info->xmit.head,
845 				      info->xmit.tail,
846 				      SERIAL_XMIT_SIZE);
847 		if (count < c)
848 			c = count;
849 		if (c <= 0) {
850 			break;
851 		}
852 		memcpy(info->xmit.buf + info->xmit.head, buf, c);
853 		info->xmit.head = ((info->xmit.head + c) &
854 				   (SERIAL_XMIT_SIZE-1));
855 		buf += c;
856 		count -= c;
857 		ret += c;
858 	}
859 	local_irq_restore(flags);
860 
861 	if (info->xmit.head != info->xmit.tail
862 	    && !tty->stopped
863 	    && !tty->hw_stopped
864 	    && !(info->IER & UART_IER_THRI)) {
865 		info->IER |= UART_IER_THRI;
866 		local_irq_disable();
867 		custom.intena = IF_SETCLR | IF_TBE;
868 		mb();
869 		/* set a pending Tx Interrupt, transmitter should restart now */
870 		custom.intreq = IF_SETCLR | IF_TBE;
871 		mb();
872 		local_irq_restore(flags);
873 	}
874 	return ret;
875 }
876 
877 static int rs_write_room(struct tty_struct *tty)
878 {
879 	struct serial_state *info = tty->driver_data;
880 
881 	if (serial_paranoia_check(info, tty->name, "rs_write_room"))
882 		return 0;
883 	return CIRC_SPACE(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
884 }
885 
886 static int rs_chars_in_buffer(struct tty_struct *tty)
887 {
888 	struct serial_state *info = tty->driver_data;
889 
890 	if (serial_paranoia_check(info, tty->name, "rs_chars_in_buffer"))
891 		return 0;
892 	return CIRC_CNT(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
893 }
894 
895 static void rs_flush_buffer(struct tty_struct *tty)
896 {
897 	struct serial_state *info = tty->driver_data;
898 	unsigned long flags;
899 
900 	if (serial_paranoia_check(info, tty->name, "rs_flush_buffer"))
901 		return;
902 	local_irq_save(flags);
903 	info->xmit.head = info->xmit.tail = 0;
904 	local_irq_restore(flags);
905 	tty_wakeup(tty);
906 }
907 
908 /*
909  * This function is used to send a high-priority XON/XOFF character to
910  * the device
911  */
912 static void rs_send_xchar(struct tty_struct *tty, char ch)
913 {
914 	struct serial_state *info = tty->driver_data;
915         unsigned long flags;
916 
917 	if (serial_paranoia_check(info, tty->name, "rs_send_xchar"))
918 		return;
919 
920 	info->x_char = ch;
921 	if (ch) {
922 		/* Make sure transmit interrupts are on */
923 
924 	        /* Check this ! */
925 	        local_irq_save(flags);
926 		if(!(custom.intenar & IF_TBE)) {
927 		    custom.intena = IF_SETCLR | IF_TBE;
928 		    mb();
929 		    /* set a pending Tx Interrupt, transmitter should restart now */
930 		    custom.intreq = IF_SETCLR | IF_TBE;
931 		    mb();
932 		}
933 		local_irq_restore(flags);
934 
935 		info->IER |= UART_IER_THRI;
936 	}
937 }
938 
939 /*
940  * ------------------------------------------------------------
941  * rs_throttle()
942  *
943  * This routine is called by the upper-layer tty layer to signal that
944  * incoming characters should be throttled.
945  * ------------------------------------------------------------
946  */
947 static void rs_throttle(struct tty_struct * tty)
948 {
949 	struct serial_state *info = tty->driver_data;
950 	unsigned long flags;
951 #ifdef SERIAL_DEBUG_THROTTLE
952 	printk("throttle %s ....\n", tty_name(tty));
953 #endif
954 
955 	if (serial_paranoia_check(info, tty->name, "rs_throttle"))
956 		return;
957 
958 	if (I_IXOFF(tty))
959 		rs_send_xchar(tty, STOP_CHAR(tty));
960 
961 	if (C_CRTSCTS(tty))
962 		info->MCR &= ~SER_RTS;
963 
964 	local_irq_save(flags);
965 	rtsdtr_ctrl(info->MCR);
966 	local_irq_restore(flags);
967 }
968 
969 static void rs_unthrottle(struct tty_struct * tty)
970 {
971 	struct serial_state *info = tty->driver_data;
972 	unsigned long flags;
973 #ifdef SERIAL_DEBUG_THROTTLE
974 	printk("unthrottle %s ....\n", tty_name(tty));
975 #endif
976 
977 	if (serial_paranoia_check(info, tty->name, "rs_unthrottle"))
978 		return;
979 
980 	if (I_IXOFF(tty)) {
981 		if (info->x_char)
982 			info->x_char = 0;
983 		else
984 			rs_send_xchar(tty, START_CHAR(tty));
985 	}
986 	if (C_CRTSCTS(tty))
987 		info->MCR |= SER_RTS;
988 	local_irq_save(flags);
989 	rtsdtr_ctrl(info->MCR);
990 	local_irq_restore(flags);
991 }
992 
993 /*
994  * ------------------------------------------------------------
995  * rs_ioctl() and friends
996  * ------------------------------------------------------------
997  */
998 
999 static int get_serial_info(struct tty_struct *tty, struct serial_struct *ss)
1000 {
1001 	struct serial_state *state = tty->driver_data;
1002 
1003 	tty_lock(tty);
1004 	ss->line = tty->index;
1005 	ss->port = state->port;
1006 	ss->flags = state->tport.flags;
1007 	ss->xmit_fifo_size = state->xmit_fifo_size;
1008 	ss->baud_base = state->baud_base;
1009 	ss->close_delay = state->tport.close_delay;
1010 	ss->closing_wait = state->tport.closing_wait;
1011 	ss->custom_divisor = state->custom_divisor;
1012 	tty_unlock(tty);
1013 	return 0;
1014 }
1015 
1016 static int set_serial_info(struct tty_struct *tty, struct serial_struct *ss)
1017 {
1018 	struct serial_state *state = tty->driver_data;
1019 	struct tty_port *port = &state->tport;
1020 	bool change_spd;
1021 	int 			retval = 0;
1022 
1023 	tty_lock(tty);
1024 	change_spd = ((ss->flags ^ port->flags) & ASYNC_SPD_MASK) ||
1025 		ss->custom_divisor != state->custom_divisor;
1026 	if (ss->irq || ss->port != state->port ||
1027 			ss->xmit_fifo_size != state->xmit_fifo_size) {
1028 		tty_unlock(tty);
1029 		return -EINVAL;
1030 	}
1031 
1032 	if (!serial_isroot()) {
1033 		if ((ss->baud_base != state->baud_base) ||
1034 		    (ss->close_delay != port->close_delay) ||
1035 		    (ss->xmit_fifo_size != state->xmit_fifo_size) ||
1036 		    ((ss->flags & ~ASYNC_USR_MASK) !=
1037 		     (port->flags & ~ASYNC_USR_MASK))) {
1038 			tty_unlock(tty);
1039 			return -EPERM;
1040 		}
1041 		port->flags = ((port->flags & ~ASYNC_USR_MASK) |
1042 			       (ss->flags & ASYNC_USR_MASK));
1043 		state->custom_divisor = ss->custom_divisor;
1044 		goto check_and_exit;
1045 	}
1046 
1047 	if (ss->baud_base < 9600) {
1048 		tty_unlock(tty);
1049 		return -EINVAL;
1050 	}
1051 
1052 	/*
1053 	 * OK, past this point, all the error checking has been done.
1054 	 * At this point, we start making changes.....
1055 	 */
1056 
1057 	state->baud_base = ss->baud_base;
1058 	port->flags = ((port->flags & ~ASYNC_FLAGS) |
1059 			(ss->flags & ASYNC_FLAGS));
1060 	state->custom_divisor = ss->custom_divisor;
1061 	port->close_delay = ss->close_delay * HZ/100;
1062 	port->closing_wait = ss->closing_wait * HZ/100;
1063 	port->low_latency = (port->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
1064 
1065 check_and_exit:
1066 	if (tty_port_initialized(port)) {
1067 		if (change_spd) {
1068 			/* warn about deprecation unless clearing */
1069 			if (ss->flags & ASYNC_SPD_MASK)
1070 				dev_warn_ratelimited(tty->dev, "use of SPD flags is deprecated\n");
1071 			change_speed(tty, state, NULL);
1072 		}
1073 	} else
1074 		retval = startup(tty, state);
1075 	tty_unlock(tty);
1076 	return retval;
1077 }
1078 
1079 /*
1080  * get_lsr_info - get line status register info
1081  *
1082  * Purpose: Let user call ioctl() to get info when the UART physically
1083  * 	    is emptied.  On bus types like RS485, the transmitter must
1084  * 	    release the bus after transmitting. This must be done when
1085  * 	    the transmit shift register is empty, not be done when the
1086  * 	    transmit holding register is empty.  This functionality
1087  * 	    allows an RS485 driver to be written in user space.
1088  */
1089 static int get_lsr_info(struct serial_state *info, unsigned int __user *value)
1090 {
1091 	unsigned char status;
1092 	unsigned int result;
1093 	unsigned long flags;
1094 
1095 	local_irq_save(flags);
1096 	status = custom.serdatr;
1097 	mb();
1098 	local_irq_restore(flags);
1099 	result = ((status & SDR_TSRE) ? TIOCSER_TEMT : 0);
1100 	if (copy_to_user(value, &result, sizeof(int)))
1101 		return -EFAULT;
1102 	return 0;
1103 }
1104 
1105 
1106 static int rs_tiocmget(struct tty_struct *tty)
1107 {
1108 	struct serial_state *info = tty->driver_data;
1109 	unsigned char control, status;
1110 	unsigned long flags;
1111 
1112 	if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
1113 		return -ENODEV;
1114 	if (tty_io_error(tty))
1115 		return -EIO;
1116 
1117 	control = info->MCR;
1118 	local_irq_save(flags);
1119 	status = ciab.pra;
1120 	local_irq_restore(flags);
1121 	return    ((control & SER_RTS) ? TIOCM_RTS : 0)
1122 		| ((control & SER_DTR) ? TIOCM_DTR : 0)
1123 		| (!(status  & SER_DCD) ? TIOCM_CAR : 0)
1124 		| (!(status  & SER_DSR) ? TIOCM_DSR : 0)
1125 		| (!(status  & SER_CTS) ? TIOCM_CTS : 0);
1126 }
1127 
1128 static int rs_tiocmset(struct tty_struct *tty, unsigned int set,
1129 						unsigned int clear)
1130 {
1131 	struct serial_state *info = tty->driver_data;
1132 	unsigned long flags;
1133 
1134 	if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
1135 		return -ENODEV;
1136 	if (tty_io_error(tty))
1137 		return -EIO;
1138 
1139 	local_irq_save(flags);
1140 	if (set & TIOCM_RTS)
1141 		info->MCR |= SER_RTS;
1142 	if (set & TIOCM_DTR)
1143 		info->MCR |= SER_DTR;
1144 	if (clear & TIOCM_RTS)
1145 		info->MCR &= ~SER_RTS;
1146 	if (clear & TIOCM_DTR)
1147 		info->MCR &= ~SER_DTR;
1148 	rtsdtr_ctrl(info->MCR);
1149 	local_irq_restore(flags);
1150 	return 0;
1151 }
1152 
1153 /*
1154  * rs_break() --- routine which turns the break handling on or off
1155  */
1156 static int rs_break(struct tty_struct *tty, int break_state)
1157 {
1158 	struct serial_state *info = tty->driver_data;
1159 	unsigned long flags;
1160 
1161 	if (serial_paranoia_check(info, tty->name, "rs_break"))
1162 		return -EINVAL;
1163 
1164 	local_irq_save(flags);
1165 	if (break_state == -1)
1166 	  custom.adkcon = AC_SETCLR | AC_UARTBRK;
1167 	else
1168 	  custom.adkcon = AC_UARTBRK;
1169 	mb();
1170 	local_irq_restore(flags);
1171 	return 0;
1172 }
1173 
1174 /*
1175  * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1176  * Return: write counters to the user passed counter struct
1177  * NB: both 1->0 and 0->1 transitions are counted except for
1178  *     RI where only 0->1 is counted.
1179  */
1180 static int rs_get_icount(struct tty_struct *tty,
1181 				struct serial_icounter_struct *icount)
1182 {
1183 	struct serial_state *info = tty->driver_data;
1184 	struct async_icount cnow;
1185 	unsigned long flags;
1186 
1187 	local_irq_save(flags);
1188 	cnow = info->icount;
1189 	local_irq_restore(flags);
1190 	icount->cts = cnow.cts;
1191 	icount->dsr = cnow.dsr;
1192 	icount->rng = cnow.rng;
1193 	icount->dcd = cnow.dcd;
1194 	icount->rx = cnow.rx;
1195 	icount->tx = cnow.tx;
1196 	icount->frame = cnow.frame;
1197 	icount->overrun = cnow.overrun;
1198 	icount->parity = cnow.parity;
1199 	icount->brk = cnow.brk;
1200 	icount->buf_overrun = cnow.buf_overrun;
1201 
1202 	return 0;
1203 }
1204 
1205 static int rs_ioctl(struct tty_struct *tty,
1206 		    unsigned int cmd, unsigned long arg)
1207 {
1208 	struct serial_state *info = tty->driver_data;
1209 	struct async_icount cprev, cnow;	/* kernel counter temps */
1210 	void __user *argp = (void __user *)arg;
1211 	unsigned long flags;
1212 	DEFINE_WAIT(wait);
1213 	int ret;
1214 
1215 	if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
1216 		return -ENODEV;
1217 
1218 	if ((cmd != TIOCSERCONFIG) &&
1219 	    (cmd != TIOCMIWAIT) && (cmd != TIOCGICOUNT)) {
1220 		if (tty_io_error(tty))
1221 		    return -EIO;
1222 	}
1223 
1224 	switch (cmd) {
1225 		case TIOCSERCONFIG:
1226 			return 0;
1227 
1228 		case TIOCSERGETLSR: /* Get line status register */
1229 			return get_lsr_info(info, argp);
1230 
1231 		/*
1232 		 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1233 		 * - mask passed in arg for lines of interest
1234  		 *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1235 		 * Caller should use TIOCGICOUNT to see which one it was
1236 		 */
1237 		case TIOCMIWAIT:
1238 			local_irq_save(flags);
1239 			/* note the counters on entry */
1240 			cprev = info->icount;
1241 			local_irq_restore(flags);
1242 			while (1) {
1243 				prepare_to_wait(&info->tport.delta_msr_wait,
1244 						&wait, TASK_INTERRUPTIBLE);
1245 				local_irq_save(flags);
1246 				cnow = info->icount; /* atomic copy */
1247 				local_irq_restore(flags);
1248 				if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
1249 				    cnow.dcd == cprev.dcd && cnow.cts == cprev.cts) {
1250 					ret = -EIO; /* no change => error */
1251 					break;
1252 				}
1253 				if ( ((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1254 				     ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1255 				     ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
1256 				     ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts)) ) {
1257 					ret = 0;
1258 					break;
1259 				}
1260 				schedule();
1261 				/* see if a signal did it */
1262 				if (signal_pending(current)) {
1263 					ret = -ERESTARTSYS;
1264 					break;
1265 				}
1266 				cprev = cnow;
1267 			}
1268 			finish_wait(&info->tport.delta_msr_wait, &wait);
1269 			return ret;
1270 
1271 		default:
1272 			return -ENOIOCTLCMD;
1273 		}
1274 	return 0;
1275 }
1276 
1277 static void rs_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
1278 {
1279 	struct serial_state *info = tty->driver_data;
1280 	unsigned long flags;
1281 	unsigned int cflag = tty->termios.c_cflag;
1282 
1283 	change_speed(tty, info, old_termios);
1284 
1285 	/* Handle transition to B0 status */
1286 	if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD)) {
1287 		info->MCR &= ~(SER_DTR|SER_RTS);
1288 		local_irq_save(flags);
1289 		rtsdtr_ctrl(info->MCR);
1290 		local_irq_restore(flags);
1291 	}
1292 
1293 	/* Handle transition away from B0 status */
1294 	if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1295 		info->MCR |= SER_DTR;
1296 		if (!C_CRTSCTS(tty) || !tty_throttled(tty))
1297 			info->MCR |= SER_RTS;
1298 		local_irq_save(flags);
1299 		rtsdtr_ctrl(info->MCR);
1300 		local_irq_restore(flags);
1301 	}
1302 
1303 	/* Handle turning off CRTSCTS */
1304 	if ((old_termios->c_cflag & CRTSCTS) && !C_CRTSCTS(tty)) {
1305 		tty->hw_stopped = 0;
1306 		rs_start(tty);
1307 	}
1308 
1309 #if 0
1310 	/*
1311 	 * No need to wake up processes in open wait, since they
1312 	 * sample the CLOCAL flag once, and don't recheck it.
1313 	 * XXX  It's not clear whether the current behavior is correct
1314 	 * or not.  Hence, this may change.....
1315 	 */
1316 	if (!(old_termios->c_cflag & CLOCAL) && C_CLOCAL(tty))
1317 		wake_up_interruptible(&info->open_wait);
1318 #endif
1319 }
1320 
1321 /*
1322  * ------------------------------------------------------------
1323  * rs_close()
1324  *
1325  * This routine is called when the serial port gets closed.  First, we
1326  * wait for the last remaining data to be sent.  Then, we unlink its
1327  * async structure from the interrupt chain if necessary, and we free
1328  * that IRQ if nothing is left in the chain.
1329  * ------------------------------------------------------------
1330  */
1331 static void rs_close(struct tty_struct *tty, struct file * filp)
1332 {
1333 	struct serial_state *state = tty->driver_data;
1334 	struct tty_port *port = &state->tport;
1335 
1336 	if (serial_paranoia_check(state, tty->name, "rs_close"))
1337 		return;
1338 
1339 	if (tty_port_close_start(port, tty, filp) == 0)
1340 		return;
1341 
1342 	/*
1343 	 * At this point we stop accepting input.  To do this, we
1344 	 * disable the receive line status interrupts, and tell the
1345 	 * interrupt driver to stop checking the data ready bit in the
1346 	 * line status register.
1347 	 */
1348 	state->read_status_mask &= ~UART_LSR_DR;
1349 	if (tty_port_initialized(port)) {
1350 	        /* disable receive interrupts */
1351 	        custom.intena = IF_RBF;
1352 		mb();
1353 		/* clear any pending receive interrupt */
1354 		custom.intreq = IF_RBF;
1355 		mb();
1356 
1357 		/*
1358 		 * Before we drop DTR, make sure the UART transmitter
1359 		 * has completely drained; this is especially
1360 		 * important if there is a transmit FIFO!
1361 		 */
1362 		rs_wait_until_sent(tty, state->timeout);
1363 	}
1364 	shutdown(tty, state);
1365 	rs_flush_buffer(tty);
1366 
1367 	tty_ldisc_flush(tty);
1368 	port->tty = NULL;
1369 
1370 	tty_port_close_end(port, tty);
1371 }
1372 
1373 /*
1374  * rs_wait_until_sent() --- wait until the transmitter is empty
1375  */
1376 static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
1377 {
1378 	struct serial_state *info = tty->driver_data;
1379 	unsigned long orig_jiffies, char_time;
1380 	int lsr;
1381 
1382 	if (serial_paranoia_check(info, tty->name, "rs_wait_until_sent"))
1383 		return;
1384 
1385 	if (info->xmit_fifo_size == 0)
1386 		return; /* Just in case.... */
1387 
1388 	orig_jiffies = jiffies;
1389 
1390 	/*
1391 	 * Set the check interval to be 1/5 of the estimated time to
1392 	 * send a single character, and make it at least 1.  The check
1393 	 * interval should also be less than the timeout.
1394 	 *
1395 	 * Note: we have to use pretty tight timings here to satisfy
1396 	 * the NIST-PCTS.
1397 	 */
1398 	char_time = (info->timeout - HZ/50) / info->xmit_fifo_size;
1399 	char_time = char_time / 5;
1400 	if (char_time == 0)
1401 		char_time = 1;
1402 	if (timeout)
1403 	  char_time = min_t(unsigned long, char_time, timeout);
1404 	/*
1405 	 * If the transmitter hasn't cleared in twice the approximate
1406 	 * amount of time to send the entire FIFO, it probably won't
1407 	 * ever clear.  This assumes the UART isn't doing flow
1408 	 * control, which is currently the case.  Hence, if it ever
1409 	 * takes longer than info->timeout, this is probably due to a
1410 	 * UART bug of some kind.  So, we clamp the timeout parameter at
1411 	 * 2*info->timeout.
1412 	 */
1413 	if (!timeout || timeout > 2*info->timeout)
1414 		timeout = 2*info->timeout;
1415 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
1416 	printk("In rs_wait_until_sent(%d) check=%lu...", timeout, char_time);
1417 	printk("jiff=%lu...", jiffies);
1418 #endif
1419 	while(!((lsr = custom.serdatr) & SDR_TSRE)) {
1420 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
1421 		printk("serdatr = %d (jiff=%lu)...", lsr, jiffies);
1422 #endif
1423 		msleep_interruptible(jiffies_to_msecs(char_time));
1424 		if (signal_pending(current))
1425 			break;
1426 		if (timeout && time_after(jiffies, orig_jiffies + timeout))
1427 			break;
1428 	}
1429 	__set_current_state(TASK_RUNNING);
1430 
1431 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
1432 	printk("lsr = %d (jiff=%lu)...done\n", lsr, jiffies);
1433 #endif
1434 }
1435 
1436 /*
1437  * rs_hangup() --- called by tty_hangup() when a hangup is signaled.
1438  */
1439 static void rs_hangup(struct tty_struct *tty)
1440 {
1441 	struct serial_state *info = tty->driver_data;
1442 
1443 	if (serial_paranoia_check(info, tty->name, "rs_hangup"))
1444 		return;
1445 
1446 	rs_flush_buffer(tty);
1447 	shutdown(tty, info);
1448 	info->tport.count = 0;
1449 	tty_port_set_active(&info->tport, 0);
1450 	info->tport.tty = NULL;
1451 	wake_up_interruptible(&info->tport.open_wait);
1452 }
1453 
1454 /*
1455  * This routine is called whenever a serial port is opened.  It
1456  * enables interrupts for a serial port, linking in its async structure into
1457  * the IRQ chain.   It also performs the serial-specific
1458  * initialization for the tty structure.
1459  */
1460 static int rs_open(struct tty_struct *tty, struct file * filp)
1461 {
1462 	struct serial_state *info = rs_table + tty->index;
1463 	struct tty_port *port = &info->tport;
1464 	int retval;
1465 
1466 	port->count++;
1467 	port->tty = tty;
1468 	tty->driver_data = info;
1469 	tty->port = port;
1470 	if (serial_paranoia_check(info, tty->name, "rs_open"))
1471 		return -ENODEV;
1472 
1473 	port->low_latency = (port->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
1474 
1475 	retval = startup(tty, info);
1476 	if (retval) {
1477 		return retval;
1478 	}
1479 
1480 	return tty_port_block_til_ready(port, tty, filp);
1481 }
1482 
1483 /*
1484  * /proc fs routines....
1485  */
1486 
1487 static inline void line_info(struct seq_file *m, int line,
1488 		struct serial_state *state)
1489 {
1490 	char	stat_buf[30], control, status;
1491 	unsigned long flags;
1492 
1493 	seq_printf(m, "%d: uart:amiga_builtin", line);
1494 
1495 	local_irq_save(flags);
1496 	status = ciab.pra;
1497 	control = tty_port_initialized(&state->tport) ? state->MCR : status;
1498 	local_irq_restore(flags);
1499 
1500 	stat_buf[0] = 0;
1501 	stat_buf[1] = 0;
1502 	if(!(control & SER_RTS))
1503 		strcat(stat_buf, "|RTS");
1504 	if(!(status & SER_CTS))
1505 		strcat(stat_buf, "|CTS");
1506 	if(!(control & SER_DTR))
1507 		strcat(stat_buf, "|DTR");
1508 	if(!(status & SER_DSR))
1509 		strcat(stat_buf, "|DSR");
1510 	if(!(status & SER_DCD))
1511 		strcat(stat_buf, "|CD");
1512 
1513 	if (state->quot)
1514 		seq_printf(m, " baud:%d", state->baud_base / state->quot);
1515 
1516 	seq_printf(m, " tx:%d rx:%d", state->icount.tx, state->icount.rx);
1517 
1518 	if (state->icount.frame)
1519 		seq_printf(m, " fe:%d", state->icount.frame);
1520 
1521 	if (state->icount.parity)
1522 		seq_printf(m, " pe:%d", state->icount.parity);
1523 
1524 	if (state->icount.brk)
1525 		seq_printf(m, " brk:%d", state->icount.brk);
1526 
1527 	if (state->icount.overrun)
1528 		seq_printf(m, " oe:%d", state->icount.overrun);
1529 
1530 	/*
1531 	 * Last thing is the RS-232 status lines
1532 	 */
1533 	seq_printf(m, " %s\n", stat_buf+1);
1534 }
1535 
1536 static int rs_proc_show(struct seq_file *m, void *v)
1537 {
1538 	seq_printf(m, "serinfo:1.0 driver:%s\n", serial_version);
1539 	line_info(m, 0, &rs_table[0]);
1540 	return 0;
1541 }
1542 
1543 /*
1544  * ---------------------------------------------------------------------
1545  * rs_init() and friends
1546  *
1547  * rs_init() is called at boot-time to initialize the serial driver.
1548  * ---------------------------------------------------------------------
1549  */
1550 
1551 /*
1552  * This routine prints out the appropriate serial driver version
1553  * number, and identifies which options were configured into this
1554  * driver.
1555  */
1556 static void show_serial_version(void)
1557 {
1558  	printk(KERN_INFO "%s version %s\n", serial_name, serial_version);
1559 }
1560 
1561 
1562 static const struct tty_operations serial_ops = {
1563 	.open = rs_open,
1564 	.close = rs_close,
1565 	.write = rs_write,
1566 	.put_char = rs_put_char,
1567 	.flush_chars = rs_flush_chars,
1568 	.write_room = rs_write_room,
1569 	.chars_in_buffer = rs_chars_in_buffer,
1570 	.flush_buffer = rs_flush_buffer,
1571 	.ioctl = rs_ioctl,
1572 	.throttle = rs_throttle,
1573 	.unthrottle = rs_unthrottle,
1574 	.set_termios = rs_set_termios,
1575 	.stop = rs_stop,
1576 	.start = rs_start,
1577 	.hangup = rs_hangup,
1578 	.break_ctl = rs_break,
1579 	.send_xchar = rs_send_xchar,
1580 	.wait_until_sent = rs_wait_until_sent,
1581 	.tiocmget = rs_tiocmget,
1582 	.tiocmset = rs_tiocmset,
1583 	.get_icount = rs_get_icount,
1584 	.set_serial = set_serial_info,
1585 	.get_serial = get_serial_info,
1586 	.proc_show = rs_proc_show,
1587 };
1588 
1589 static int amiga_carrier_raised(struct tty_port *port)
1590 {
1591 	return !(ciab.pra & SER_DCD);
1592 }
1593 
1594 static void amiga_dtr_rts(struct tty_port *port, int raise)
1595 {
1596 	struct serial_state *info = container_of(port, struct serial_state,
1597 			tport);
1598 	unsigned long flags;
1599 
1600 	if (raise)
1601 		info->MCR |= SER_DTR|SER_RTS;
1602 	else
1603 		info->MCR &= ~(SER_DTR|SER_RTS);
1604 
1605 	local_irq_save(flags);
1606 	rtsdtr_ctrl(info->MCR);
1607 	local_irq_restore(flags);
1608 }
1609 
1610 static const struct tty_port_operations amiga_port_ops = {
1611 	.carrier_raised = amiga_carrier_raised,
1612 	.dtr_rts = amiga_dtr_rts,
1613 };
1614 
1615 /*
1616  * The serial driver boot-time initialization code!
1617  */
1618 static int __init amiga_serial_probe(struct platform_device *pdev)
1619 {
1620 	unsigned long flags;
1621 	struct serial_state * state;
1622 	int error;
1623 
1624 	serial_driver = alloc_tty_driver(NR_PORTS);
1625 	if (!serial_driver)
1626 		return -ENOMEM;
1627 
1628 	show_serial_version();
1629 
1630 	/* Initialize the tty_driver structure */
1631 
1632 	serial_driver->driver_name = "amiserial";
1633 	serial_driver->name = "ttyS";
1634 	serial_driver->major = TTY_MAJOR;
1635 	serial_driver->minor_start = 64;
1636 	serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
1637 	serial_driver->subtype = SERIAL_TYPE_NORMAL;
1638 	serial_driver->init_termios = tty_std_termios;
1639 	serial_driver->init_termios.c_cflag =
1640 		B9600 | CS8 | CREAD | HUPCL | CLOCAL;
1641 	serial_driver->flags = TTY_DRIVER_REAL_RAW;
1642 	tty_set_operations(serial_driver, &serial_ops);
1643 
1644 	state = rs_table;
1645 	state->port = (int)&custom.serdatr; /* Just to give it a value */
1646 	state->custom_divisor = 0;
1647 	state->icount.cts = state->icount.dsr =
1648 	  state->icount.rng = state->icount.dcd = 0;
1649 	state->icount.rx = state->icount.tx = 0;
1650 	state->icount.frame = state->icount.parity = 0;
1651 	state->icount.overrun = state->icount.brk = 0;
1652 	tty_port_init(&state->tport);
1653 	state->tport.ops = &amiga_port_ops;
1654 	tty_port_link_device(&state->tport, serial_driver, 0);
1655 
1656 	error = tty_register_driver(serial_driver);
1657 	if (error)
1658 		goto fail_put_tty_driver;
1659 
1660 	printk(KERN_INFO "ttyS0 is the amiga builtin serial port\n");
1661 
1662 	/* Hardware set up */
1663 
1664 	state->baud_base = amiga_colorclock;
1665 	state->xmit_fifo_size = 1;
1666 
1667 	/* set ISRs, and then disable the rx interrupts */
1668 	error = request_irq(IRQ_AMIGA_TBE, ser_tx_int, 0, "serial TX", state);
1669 	if (error)
1670 		goto fail_unregister;
1671 
1672 	error = request_irq(IRQ_AMIGA_RBF, ser_rx_int, 0,
1673 			    "serial RX", state);
1674 	if (error)
1675 		goto fail_free_irq;
1676 
1677 	local_irq_save(flags);
1678 
1679 	/* turn off Rx and Tx interrupts */
1680 	custom.intena = IF_RBF | IF_TBE;
1681 	mb();
1682 
1683 	/* clear any pending interrupt */
1684 	custom.intreq = IF_RBF | IF_TBE;
1685 	mb();
1686 
1687 	local_irq_restore(flags);
1688 
1689 	/*
1690 	 * set the appropriate directions for the modem control flags,
1691 	 * and clear RTS and DTR
1692 	 */
1693 	ciab.ddra |= (SER_DTR | SER_RTS);   /* outputs */
1694 	ciab.ddra &= ~(SER_DCD | SER_CTS | SER_DSR);  /* inputs */
1695 
1696 	platform_set_drvdata(pdev, state);
1697 
1698 	return 0;
1699 
1700 fail_free_irq:
1701 	free_irq(IRQ_AMIGA_TBE, state);
1702 fail_unregister:
1703 	tty_unregister_driver(serial_driver);
1704 fail_put_tty_driver:
1705 	tty_port_destroy(&state->tport);
1706 	put_tty_driver(serial_driver);
1707 	return error;
1708 }
1709 
1710 static int __exit amiga_serial_remove(struct platform_device *pdev)
1711 {
1712 	int error;
1713 	struct serial_state *state = platform_get_drvdata(pdev);
1714 
1715 	/* printk("Unloading %s: version %s\n", serial_name, serial_version); */
1716 	error = tty_unregister_driver(serial_driver);
1717 	if (error)
1718 		printk("SERIAL: failed to unregister serial driver (%d)\n",
1719 		       error);
1720 	put_tty_driver(serial_driver);
1721 	tty_port_destroy(&state->tport);
1722 
1723 	free_irq(IRQ_AMIGA_TBE, state);
1724 	free_irq(IRQ_AMIGA_RBF, state);
1725 
1726 	return error;
1727 }
1728 
1729 static struct platform_driver amiga_serial_driver = {
1730 	.remove = __exit_p(amiga_serial_remove),
1731 	.driver   = {
1732 		.name	= "amiga-serial",
1733 	},
1734 };
1735 
1736 module_platform_driver_probe(amiga_serial_driver, amiga_serial_probe);
1737 
1738 
1739 #if defined(CONFIG_SERIAL_CONSOLE) && !defined(MODULE)
1740 
1741 /*
1742  * ------------------------------------------------------------
1743  * Serial console driver
1744  * ------------------------------------------------------------
1745  */
1746 
1747 static void amiga_serial_putc(char c)
1748 {
1749 	custom.serdat = (unsigned char)c | 0x100;
1750 	while (!(custom.serdatr & 0x2000))
1751 		barrier();
1752 }
1753 
1754 /*
1755  *	Print a string to the serial port trying not to disturb
1756  *	any possible real use of the port...
1757  *
1758  *	The console must be locked when we get here.
1759  */
1760 static void serial_console_write(struct console *co, const char *s,
1761 				unsigned count)
1762 {
1763 	unsigned short intena = custom.intenar;
1764 
1765 	custom.intena = IF_TBE;
1766 
1767 	while (count--) {
1768 		if (*s == '\n')
1769 			amiga_serial_putc('\r');
1770 		amiga_serial_putc(*s++);
1771 	}
1772 
1773 	custom.intena = IF_SETCLR | (intena & IF_TBE);
1774 }
1775 
1776 static struct tty_driver *serial_console_device(struct console *c, int *index)
1777 {
1778 	*index = 0;
1779 	return serial_driver;
1780 }
1781 
1782 static struct console sercons = {
1783 	.name =		"ttyS",
1784 	.write =	serial_console_write,
1785 	.device =	serial_console_device,
1786 	.flags =	CON_PRINTBUFFER,
1787 	.index =	-1,
1788 };
1789 
1790 /*
1791  *	Register console.
1792  */
1793 static int __init amiserial_console_init(void)
1794 {
1795 	if (!MACH_IS_AMIGA)
1796 		return -ENODEV;
1797 
1798 	register_console(&sercons);
1799 	return 0;
1800 }
1801 console_initcall(amiserial_console_init);
1802 
1803 #endif /* CONFIG_SERIAL_CONSOLE && !MODULE */
1804 
1805 MODULE_LICENSE("GPL");
1806 MODULE_ALIAS("platform:amiga-serial");
1807