xref: /linux/drivers/tty/amiserial.c (revision ec2212088c42ff7d1362629ec26dda4f3e8bdad3)
1 /*
2  * Serial driver for the amiga builtin port.
3  *
4  * This code was created by taking serial.c version 4.30 from kernel
5  * release 2.3.22, replacing all hardware related stuff with the
6  * corresponding amiga hardware actions, and removing all irrelevant
7  * code. As a consequence, it uses many of the constants and names
8  * associated with the registers and bits of 16550 compatible UARTS -
9  * but only to keep track of status, etc in the state variables. It
10  * was done this was to make it easier to keep the code in line with
11  * (non hardware specific) changes to serial.c.
12  *
13  * The port is registered with the tty driver as minor device 64, and
14  * therefore other ports should should only use 65 upwards.
15  *
16  * Richard Lucock 28/12/99
17  *
18  *  Copyright (C) 1991, 1992  Linus Torvalds
19  *  Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997,
20  * 		1998, 1999  Theodore Ts'o
21  *
22  */
23 
24 /*
25  * Serial driver configuration section.  Here are the various options:
26  *
27  * SERIAL_PARANOIA_CHECK
28  * 		Check the magic number for the async_structure where
29  * 		ever possible.
30  */
31 
32 #include <linux/delay.h>
33 
34 #undef SERIAL_PARANOIA_CHECK
35 #define SERIAL_DO_RESTART
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 #include <asm/system.h>
89 
90 #include <asm/irq.h>
91 
92 #include <asm/amigahw.h>
93 #include <asm/amigaints.h>
94 
95 struct serial_state {
96 	struct tty_port		tport;
97 	struct circ_buf		xmit;
98 	struct async_icount	icount;
99 
100 	unsigned long		port;
101 	int			baud_base;
102 	int			xmit_fifo_size;
103 	int			custom_divisor;
104 	int			read_status_mask;
105 	int			ignore_status_mask;
106 	int			timeout;
107 	int			quot;
108 	int			IER; 	/* Interrupt Enable Register */
109 	int			MCR; 	/* Modem control register */
110 	int			x_char;	/* xon/xoff character */
111 };
112 
113 #define custom amiga_custom
114 static char *serial_name = "Amiga-builtin serial driver";
115 
116 static struct tty_driver *serial_driver;
117 
118 /* number of characters left in xmit buffer before we ask for more */
119 #define WAKEUP_CHARS 256
120 
121 static unsigned char current_ctl_bits;
122 
123 static void change_speed(struct tty_struct *tty, struct serial_state *info,
124 		struct ktermios *old);
125 static void rs_wait_until_sent(struct tty_struct *tty, int timeout);
126 
127 
128 static struct serial_state rs_table[1];
129 
130 #define NR_PORTS ARRAY_SIZE(rs_table)
131 
132 #include <asm/uaccess.h>
133 
134 #define serial_isroot()	(capable(CAP_SYS_ADMIN))
135 
136 
137 static inline int serial_paranoia_check(struct serial_state *info,
138 					char *name, const char *routine)
139 {
140 #ifdef SERIAL_PARANOIA_CHECK
141 	static const char *badmagic =
142 		"Warning: bad magic number for serial struct (%s) in %s\n";
143 	static const char *badinfo =
144 		"Warning: null async_struct for (%s) in %s\n";
145 
146 	if (!info) {
147 		printk(badinfo, name, routine);
148 		return 1;
149 	}
150 	if (info->magic != SERIAL_MAGIC) {
151 		printk(badmagic, name, routine);
152 		return 1;
153 	}
154 #endif
155 	return 0;
156 }
157 
158 /* some serial hardware definitions */
159 #define SDR_OVRUN   (1<<15)
160 #define SDR_RBF     (1<<14)
161 #define SDR_TBE     (1<<13)
162 #define SDR_TSRE    (1<<12)
163 
164 #define SERPER_PARENB    (1<<15)
165 
166 #define AC_SETCLR   (1<<15)
167 #define AC_UARTBRK  (1<<11)
168 
169 #define SER_DTR     (1<<7)
170 #define SER_RTS     (1<<6)
171 #define SER_DCD     (1<<5)
172 #define SER_CTS     (1<<4)
173 #define SER_DSR     (1<<3)
174 
175 static __inline__ void rtsdtr_ctrl(int bits)
176 {
177     ciab.pra = ((bits & (SER_RTS | SER_DTR)) ^ (SER_RTS | SER_DTR)) | (ciab.pra & ~(SER_RTS | SER_DTR));
178 }
179 
180 /*
181  * ------------------------------------------------------------
182  * rs_stop() and rs_start()
183  *
184  * This routines are called before setting or resetting tty->stopped.
185  * They enable or disable transmitter interrupts, as necessary.
186  * ------------------------------------------------------------
187  */
188 static void rs_stop(struct tty_struct *tty)
189 {
190 	struct serial_state *info = tty->driver_data;
191 	unsigned long flags;
192 
193 	if (serial_paranoia_check(info, tty->name, "rs_stop"))
194 		return;
195 
196 	local_irq_save(flags);
197 	if (info->IER & UART_IER_THRI) {
198 		info->IER &= ~UART_IER_THRI;
199 		/* disable Tx interrupt and remove any pending interrupts */
200 		custom.intena = IF_TBE;
201 		mb();
202 		custom.intreq = IF_TBE;
203 		mb();
204 	}
205 	local_irq_restore(flags);
206 }
207 
208 static void rs_start(struct tty_struct *tty)
209 {
210 	struct serial_state *info = tty->driver_data;
211 	unsigned long flags;
212 
213 	if (serial_paranoia_check(info, tty->name, "rs_start"))
214 		return;
215 
216 	local_irq_save(flags);
217 	if (info->xmit.head != info->xmit.tail
218 	    && info->xmit.buf
219 	    && !(info->IER & UART_IER_THRI)) {
220 		info->IER |= UART_IER_THRI;
221 		custom.intena = IF_SETCLR | IF_TBE;
222 		mb();
223 		/* set a pending Tx Interrupt, transmitter should restart now */
224 		custom.intreq = IF_SETCLR | IF_TBE;
225 		mb();
226 	}
227 	local_irq_restore(flags);
228 }
229 
230 /*
231  * ----------------------------------------------------------------------
232  *
233  * Here starts the interrupt handling routines.  All of the following
234  * subroutines are declared as inline and are folded into
235  * rs_interrupt().  They were separated out for readability's sake.
236  *
237  * Note: rs_interrupt() is a "fast" interrupt, which means that it
238  * runs with interrupts turned off.  People who may want to modify
239  * rs_interrupt() should try to keep the interrupt handler as fast as
240  * possible.  After you are done making modifications, it is not a bad
241  * idea to do:
242  *
243  * gcc -S -DKERNEL -Wall -Wstrict-prototypes -O6 -fomit-frame-pointer serial.c
244  *
245  * and look at the resulting assemble code in serial.s.
246  *
247  * 				- Ted Ts'o (tytso@mit.edu), 7-Mar-93
248  * -----------------------------------------------------------------------
249  */
250 
251 static void receive_chars(struct serial_state *info)
252 {
253         int status;
254 	int serdatr;
255 	struct tty_struct *tty = info->tport.tty;
256 	unsigned char ch, flag;
257 	struct	async_icount *icount;
258 	int oe = 0;
259 
260 	icount = &info->icount;
261 
262 	status = UART_LSR_DR; /* We obviously have a character! */
263 	serdatr = custom.serdatr;
264 	mb();
265 	custom.intreq = IF_RBF;
266 	mb();
267 
268 	if((serdatr & 0x1ff) == 0)
269 	    status |= UART_LSR_BI;
270 	if(serdatr & SDR_OVRUN)
271 	    status |= UART_LSR_OE;
272 
273 	ch = serdatr & 0xff;
274 	icount->rx++;
275 
276 #ifdef SERIAL_DEBUG_INTR
277 	printk("DR%02x:%02x...", ch, status);
278 #endif
279 	flag = TTY_NORMAL;
280 
281 	/*
282 	 * We don't handle parity or frame errors - but I have left
283 	 * the code in, since I'm not sure that the errors can't be
284 	 * detected.
285 	 */
286 
287 	if (status & (UART_LSR_BI | UART_LSR_PE |
288 		      UART_LSR_FE | UART_LSR_OE)) {
289 	  /*
290 	   * For statistics only
291 	   */
292 	  if (status & UART_LSR_BI) {
293 	    status &= ~(UART_LSR_FE | UART_LSR_PE);
294 	    icount->brk++;
295 	  } else if (status & UART_LSR_PE)
296 	    icount->parity++;
297 	  else if (status & UART_LSR_FE)
298 	    icount->frame++;
299 	  if (status & UART_LSR_OE)
300 	    icount->overrun++;
301 
302 	  /*
303 	   * Now check to see if character should be
304 	   * ignored, and mask off conditions which
305 	   * should be ignored.
306 	   */
307 	  if (status & info->ignore_status_mask)
308 	    goto out;
309 
310 	  status &= info->read_status_mask;
311 
312 	  if (status & (UART_LSR_BI)) {
313 #ifdef SERIAL_DEBUG_INTR
314 	    printk("handling break....");
315 #endif
316 	    flag = TTY_BREAK;
317 	    if (info->tport.flags & ASYNC_SAK)
318 	      do_SAK(tty);
319 	  } else if (status & UART_LSR_PE)
320 	    flag = TTY_PARITY;
321 	  else if (status & UART_LSR_FE)
322 	    flag = TTY_FRAME;
323 	  if (status & UART_LSR_OE) {
324 	    /*
325 	     * Overrun is special, since it's
326 	     * reported immediately, and doesn't
327 	     * affect the current character
328 	     */
329 	     oe = 1;
330 	  }
331 	}
332 	tty_insert_flip_char(tty, ch, flag);
333 	if (oe == 1)
334 		tty_insert_flip_char(tty, 0, TTY_OVERRUN);
335 	tty_flip_buffer_push(tty);
336 out:
337 	return;
338 }
339 
340 static void transmit_chars(struct serial_state *info)
341 {
342 	custom.intreq = IF_TBE;
343 	mb();
344 	if (info->x_char) {
345 	        custom.serdat = info->x_char | 0x100;
346 		mb();
347 		info->icount.tx++;
348 		info->x_char = 0;
349 		return;
350 	}
351 	if (info->xmit.head == info->xmit.tail
352 	    || info->tport.tty->stopped
353 	    || info->tport.tty->hw_stopped) {
354 		info->IER &= ~UART_IER_THRI;
355 	        custom.intena = IF_TBE;
356 		mb();
357 		return;
358 	}
359 
360 	custom.serdat = info->xmit.buf[info->xmit.tail++] | 0x100;
361 	mb();
362 	info->xmit.tail = info->xmit.tail & (SERIAL_XMIT_SIZE-1);
363 	info->icount.tx++;
364 
365 	if (CIRC_CNT(info->xmit.head,
366 		     info->xmit.tail,
367 		     SERIAL_XMIT_SIZE) < WAKEUP_CHARS)
368 		tty_wakeup(info->tport.tty);
369 
370 #ifdef SERIAL_DEBUG_INTR
371 	printk("THRE...");
372 #endif
373 	if (info->xmit.head == info->xmit.tail) {
374 	        custom.intena = IF_TBE;
375 		mb();
376 		info->IER &= ~UART_IER_THRI;
377 	}
378 }
379 
380 static void check_modem_status(struct serial_state *info)
381 {
382 	struct tty_port *port = &info->tport;
383 	unsigned char status = ciab.pra & (SER_DCD | SER_CTS | SER_DSR);
384 	unsigned char dstatus;
385 	struct	async_icount *icount;
386 
387 	/* Determine bits that have changed */
388 	dstatus = status ^ current_ctl_bits;
389 	current_ctl_bits = status;
390 
391 	if (dstatus) {
392 		icount = &info->icount;
393 		/* update input line counters */
394 		if (dstatus & SER_DSR)
395 			icount->dsr++;
396 		if (dstatus & SER_DCD) {
397 			icount->dcd++;
398 #ifdef CONFIG_HARD_PPS
399 			if ((port->flags & ASYNC_HARDPPS_CD) &&
400 			    !(status & SER_DCD))
401 				hardpps();
402 #endif
403 		}
404 		if (dstatus & SER_CTS)
405 			icount->cts++;
406 		wake_up_interruptible(&port->delta_msr_wait);
407 	}
408 
409 	if ((port->flags & ASYNC_CHECK_CD) && (dstatus & SER_DCD)) {
410 #if (defined(SERIAL_DEBUG_OPEN) || defined(SERIAL_DEBUG_INTR))
411 		printk("ttyS%d CD now %s...", info->line,
412 		       (!(status & SER_DCD)) ? "on" : "off");
413 #endif
414 		if (!(status & SER_DCD))
415 			wake_up_interruptible(&port->open_wait);
416 		else {
417 #ifdef SERIAL_DEBUG_OPEN
418 			printk("doing serial hangup...");
419 #endif
420 			if (port->tty)
421 				tty_hangup(port->tty);
422 		}
423 	}
424 	if (port->flags & ASYNC_CTS_FLOW) {
425 		if (port->tty->hw_stopped) {
426 			if (!(status & SER_CTS)) {
427 #if (defined(SERIAL_DEBUG_INTR) || defined(SERIAL_DEBUG_FLOW))
428 				printk("CTS tx start...");
429 #endif
430 				port->tty->hw_stopped = 0;
431 				info->IER |= UART_IER_THRI;
432 				custom.intena = IF_SETCLR | IF_TBE;
433 				mb();
434 				/* set a pending Tx Interrupt, transmitter should restart now */
435 				custom.intreq = IF_SETCLR | IF_TBE;
436 				mb();
437 				tty_wakeup(port->tty);
438 				return;
439 			}
440 		} else {
441 			if ((status & SER_CTS)) {
442 #if (defined(SERIAL_DEBUG_INTR) || defined(SERIAL_DEBUG_FLOW))
443 				printk("CTS tx stop...");
444 #endif
445 				port->tty->hw_stopped = 1;
446 				info->IER &= ~UART_IER_THRI;
447 				/* disable Tx interrupt and remove any pending interrupts */
448 				custom.intena = IF_TBE;
449 				mb();
450 				custom.intreq = IF_TBE;
451 				mb();
452 			}
453 		}
454 	}
455 }
456 
457 static irqreturn_t ser_vbl_int( int irq, void *data)
458 {
459         /* vbl is just a periodic interrupt we tie into to update modem status */
460 	struct serial_state *info = data;
461 	/*
462 	 * TBD - is it better to unregister from this interrupt or to
463 	 * ignore it if MSI is clear ?
464 	 */
465 	if(info->IER & UART_IER_MSI)
466 	  check_modem_status(info);
467 	return IRQ_HANDLED;
468 }
469 
470 static irqreturn_t ser_rx_int(int irq, void *dev_id)
471 {
472 	struct serial_state *info = dev_id;
473 
474 #ifdef SERIAL_DEBUG_INTR
475 	printk("ser_rx_int...");
476 #endif
477 
478 	if (!info->tport.tty)
479 		return IRQ_NONE;
480 
481 	receive_chars(info);
482 #ifdef SERIAL_DEBUG_INTR
483 	printk("end.\n");
484 #endif
485 	return IRQ_HANDLED;
486 }
487 
488 static irqreturn_t ser_tx_int(int irq, void *dev_id)
489 {
490 	struct serial_state *info = dev_id;
491 
492 	if (custom.serdatr & SDR_TBE) {
493 #ifdef SERIAL_DEBUG_INTR
494 	  printk("ser_tx_int...");
495 #endif
496 
497 	  if (!info->tport.tty)
498 		return IRQ_NONE;
499 
500 	  transmit_chars(info);
501 #ifdef SERIAL_DEBUG_INTR
502 	  printk("end.\n");
503 #endif
504 	}
505 	return IRQ_HANDLED;
506 }
507 
508 /*
509  * -------------------------------------------------------------------
510  * Here ends the serial interrupt routines.
511  * -------------------------------------------------------------------
512  */
513 
514 /*
515  * ---------------------------------------------------------------
516  * Low level utility subroutines for the serial driver:  routines to
517  * figure out the appropriate timeout for an interrupt chain, routines
518  * to initialize and startup a serial port, and routines to shutdown a
519  * serial port.  Useful stuff like that.
520  * ---------------------------------------------------------------
521  */
522 
523 static int startup(struct tty_struct *tty, struct serial_state *info)
524 {
525 	struct tty_port *port = &info->tport;
526 	unsigned long flags;
527 	int	retval=0;
528 	unsigned long page;
529 
530 	page = get_zeroed_page(GFP_KERNEL);
531 	if (!page)
532 		return -ENOMEM;
533 
534 	local_irq_save(flags);
535 
536 	if (port->flags & ASYNC_INITIALIZED) {
537 		free_page(page);
538 		goto errout;
539 	}
540 
541 	if (info->xmit.buf)
542 		free_page(page);
543 	else
544 		info->xmit.buf = (unsigned char *) page;
545 
546 #ifdef SERIAL_DEBUG_OPEN
547 	printk("starting up ttys%d ...", info->line);
548 #endif
549 
550 	/* Clear anything in the input buffer */
551 
552 	custom.intreq = IF_RBF;
553 	mb();
554 
555 	retval = request_irq(IRQ_AMIGA_VERTB, ser_vbl_int, 0, "serial status", info);
556 	if (retval) {
557 	  if (serial_isroot()) {
558 	      set_bit(TTY_IO_ERROR, &tty->flags);
559 	    retval = 0;
560 	  }
561 	  goto errout;
562 	}
563 
564 	/* enable both Rx and Tx interrupts */
565 	custom.intena = IF_SETCLR | IF_RBF | IF_TBE;
566 	mb();
567 	info->IER = UART_IER_MSI;
568 
569 	/* remember current state of the DCD and CTS bits */
570 	current_ctl_bits = ciab.pra & (SER_DCD | SER_CTS | SER_DSR);
571 
572 	info->MCR = 0;
573 	if (C_BAUD(tty))
574 	  info->MCR = SER_DTR | SER_RTS;
575 	rtsdtr_ctrl(info->MCR);
576 
577 	clear_bit(TTY_IO_ERROR, &tty->flags);
578 	info->xmit.head = info->xmit.tail = 0;
579 
580 	/*
581 	 * Set up the tty->alt_speed kludge
582 	 */
583 	if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
584 		tty->alt_speed = 57600;
585 	if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
586 		tty->alt_speed = 115200;
587 	if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
588 		tty->alt_speed = 230400;
589 	if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
590 		tty->alt_speed = 460800;
591 
592 	/*
593 	 * and set the speed of the serial port
594 	 */
595 	change_speed(tty, info, NULL);
596 
597 	port->flags |= ASYNC_INITIALIZED;
598 	local_irq_restore(flags);
599 	return 0;
600 
601 errout:
602 	local_irq_restore(flags);
603 	return retval;
604 }
605 
606 /*
607  * This routine will shutdown a serial port; interrupts are disabled, and
608  * DTR is dropped if the hangup on close termio flag is on.
609  */
610 static void shutdown(struct tty_struct *tty, struct serial_state *info)
611 {
612 	unsigned long	flags;
613 	struct serial_state *state;
614 
615 	if (!(info->tport.flags & ASYNC_INITIALIZED))
616 		return;
617 
618 	state = info;
619 
620 #ifdef SERIAL_DEBUG_OPEN
621 	printk("Shutting down serial port %d ....\n", info->line);
622 #endif
623 
624 	local_irq_save(flags); /* Disable interrupts */
625 
626 	/*
627 	 * clear delta_msr_wait queue to avoid mem leaks: we may free the irq
628 	 * here so the queue might never be waken up
629 	 */
630 	wake_up_interruptible(&info->tport.delta_msr_wait);
631 
632 	/*
633 	 * Free the IRQ, if necessary
634 	 */
635 	free_irq(IRQ_AMIGA_VERTB, info);
636 
637 	if (info->xmit.buf) {
638 		free_page((unsigned long) info->xmit.buf);
639 		info->xmit.buf = NULL;
640 	}
641 
642 	info->IER = 0;
643 	custom.intena = IF_RBF | IF_TBE;
644 	mb();
645 
646 	/* disable break condition */
647 	custom.adkcon = AC_UARTBRK;
648 	mb();
649 
650 	if (tty->termios->c_cflag & HUPCL)
651 		info->MCR &= ~(SER_DTR|SER_RTS);
652 	rtsdtr_ctrl(info->MCR);
653 
654 	set_bit(TTY_IO_ERROR, &tty->flags);
655 
656 	info->tport.flags &= ~ASYNC_INITIALIZED;
657 	local_irq_restore(flags);
658 }
659 
660 
661 /*
662  * This routine is called to set the UART divisor registers to match
663  * the specified baud rate for a serial port.
664  */
665 static void change_speed(struct tty_struct *tty, struct serial_state *info,
666 			 struct ktermios *old_termios)
667 {
668 	struct tty_port *port = &info->tport;
669 	int	quot = 0, baud_base, baud;
670 	unsigned cflag, cval = 0;
671 	int	bits;
672 	unsigned long	flags;
673 
674 	cflag = tty->termios->c_cflag;
675 
676 	/* Byte size is always 8 bits plus parity bit if requested */
677 
678 	cval = 3; bits = 10;
679 	if (cflag & CSTOPB) {
680 		cval |= 0x04;
681 		bits++;
682 	}
683 	if (cflag & PARENB) {
684 		cval |= UART_LCR_PARITY;
685 		bits++;
686 	}
687 	if (!(cflag & PARODD))
688 		cval |= UART_LCR_EPAR;
689 #ifdef CMSPAR
690 	if (cflag & CMSPAR)
691 		cval |= UART_LCR_SPAR;
692 #endif
693 
694 	/* Determine divisor based on baud rate */
695 	baud = tty_get_baud_rate(tty);
696 	if (!baud)
697 		baud = 9600;	/* B0 transition handled in rs_set_termios */
698 	baud_base = info->baud_base;
699 	if (baud == 38400 && (port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST)
700 		quot = info->custom_divisor;
701 	else {
702 		if (baud == 134)
703 			/* Special case since 134 is really 134.5 */
704 			quot = (2*baud_base / 269);
705 		else if (baud)
706 			quot = baud_base / baud;
707 	}
708 	/* If the quotient is zero refuse the change */
709 	if (!quot && old_termios) {
710 		/* FIXME: Will need updating for new tty in the end */
711 		tty->termios->c_cflag &= ~CBAUD;
712 		tty->termios->c_cflag |= (old_termios->c_cflag & CBAUD);
713 		baud = tty_get_baud_rate(tty);
714 		if (!baud)
715 			baud = 9600;
716 		if (baud == 38400 &&
717 		    (port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST)
718 			quot = info->custom_divisor;
719 		else {
720 			if (baud == 134)
721 				/* Special case since 134 is really 134.5 */
722 				quot = (2*baud_base / 269);
723 			else if (baud)
724 				quot = baud_base / baud;
725 		}
726 	}
727 	/* As a last resort, if the quotient is zero, default to 9600 bps */
728 	if (!quot)
729 		quot = baud_base / 9600;
730 	info->quot = quot;
731 	info->timeout = ((info->xmit_fifo_size*HZ*bits*quot) / baud_base);
732 	info->timeout += HZ/50;		/* Add .02 seconds of slop */
733 
734 	/* CTS flow control flag and modem status interrupts */
735 	info->IER &= ~UART_IER_MSI;
736 	if (port->flags & ASYNC_HARDPPS_CD)
737 		info->IER |= UART_IER_MSI;
738 	if (cflag & CRTSCTS) {
739 		port->flags |= ASYNC_CTS_FLOW;
740 		info->IER |= UART_IER_MSI;
741 	} else
742 		port->flags &= ~ASYNC_CTS_FLOW;
743 	if (cflag & CLOCAL)
744 		port->flags &= ~ASYNC_CHECK_CD;
745 	else {
746 		port->flags |= ASYNC_CHECK_CD;
747 		info->IER |= UART_IER_MSI;
748 	}
749 	/* TBD:
750 	 * Does clearing IER_MSI imply that we should disable the VBL interrupt ?
751 	 */
752 
753 	/*
754 	 * Set up parity check flag
755 	 */
756 
757 	info->read_status_mask = UART_LSR_OE | UART_LSR_DR;
758 	if (I_INPCK(tty))
759 		info->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
760 	if (I_BRKINT(tty) || I_PARMRK(tty))
761 		info->read_status_mask |= UART_LSR_BI;
762 
763 	/*
764 	 * Characters to ignore
765 	 */
766 	info->ignore_status_mask = 0;
767 	if (I_IGNPAR(tty))
768 		info->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
769 	if (I_IGNBRK(tty)) {
770 		info->ignore_status_mask |= UART_LSR_BI;
771 		/*
772 		 * If we're ignore parity and break indicators, ignore
773 		 * overruns too.  (For real raw support).
774 		 */
775 		if (I_IGNPAR(tty))
776 			info->ignore_status_mask |= UART_LSR_OE;
777 	}
778 	/*
779 	 * !!! ignore all characters if CREAD is not set
780 	 */
781 	if ((cflag & CREAD) == 0)
782 		info->ignore_status_mask |= UART_LSR_DR;
783 	local_irq_save(flags);
784 
785 	{
786 	  short serper;
787 
788 	/* Set up the baud rate */
789 	  serper = quot - 1;
790 
791 	/* Enable or disable parity bit */
792 
793 	if(cval & UART_LCR_PARITY)
794 	  serper |= (SERPER_PARENB);
795 
796 	custom.serper = serper;
797 	mb();
798 	}
799 
800 	local_irq_restore(flags);
801 }
802 
803 static int rs_put_char(struct tty_struct *tty, unsigned char ch)
804 {
805 	struct serial_state *info;
806 	unsigned long flags;
807 
808 	info = tty->driver_data;
809 
810 	if (serial_paranoia_check(info, tty->name, "rs_put_char"))
811 		return 0;
812 
813 	if (!info->xmit.buf)
814 		return 0;
815 
816 	local_irq_save(flags);
817 	if (CIRC_SPACE(info->xmit.head,
818 		       info->xmit.tail,
819 		       SERIAL_XMIT_SIZE) == 0) {
820 		local_irq_restore(flags);
821 		return 0;
822 	}
823 
824 	info->xmit.buf[info->xmit.head++] = ch;
825 	info->xmit.head &= SERIAL_XMIT_SIZE-1;
826 	local_irq_restore(flags);
827 	return 1;
828 }
829 
830 static void rs_flush_chars(struct tty_struct *tty)
831 {
832 	struct serial_state *info = tty->driver_data;
833 	unsigned long flags;
834 
835 	if (serial_paranoia_check(info, tty->name, "rs_flush_chars"))
836 		return;
837 
838 	if (info->xmit.head == info->xmit.tail
839 	    || tty->stopped
840 	    || tty->hw_stopped
841 	    || !info->xmit.buf)
842 		return;
843 
844 	local_irq_save(flags);
845 	info->IER |= UART_IER_THRI;
846 	custom.intena = IF_SETCLR | IF_TBE;
847 	mb();
848 	/* set a pending Tx Interrupt, transmitter should restart now */
849 	custom.intreq = IF_SETCLR | IF_TBE;
850 	mb();
851 	local_irq_restore(flags);
852 }
853 
854 static int rs_write(struct tty_struct * tty, const unsigned char *buf, int count)
855 {
856 	int	c, ret = 0;
857 	struct serial_state *info = tty->driver_data;
858 	unsigned long flags;
859 
860 	if (serial_paranoia_check(info, tty->name, "rs_write"))
861 		return 0;
862 
863 	if (!info->xmit.buf)
864 		return 0;
865 
866 	local_irq_save(flags);
867 	while (1) {
868 		c = CIRC_SPACE_TO_END(info->xmit.head,
869 				      info->xmit.tail,
870 				      SERIAL_XMIT_SIZE);
871 		if (count < c)
872 			c = count;
873 		if (c <= 0) {
874 			break;
875 		}
876 		memcpy(info->xmit.buf + info->xmit.head, buf, c);
877 		info->xmit.head = ((info->xmit.head + c) &
878 				   (SERIAL_XMIT_SIZE-1));
879 		buf += c;
880 		count -= c;
881 		ret += c;
882 	}
883 	local_irq_restore(flags);
884 
885 	if (info->xmit.head != info->xmit.tail
886 	    && !tty->stopped
887 	    && !tty->hw_stopped
888 	    && !(info->IER & UART_IER_THRI)) {
889 		info->IER |= UART_IER_THRI;
890 		local_irq_disable();
891 		custom.intena = IF_SETCLR | IF_TBE;
892 		mb();
893 		/* set a pending Tx Interrupt, transmitter should restart now */
894 		custom.intreq = IF_SETCLR | IF_TBE;
895 		mb();
896 		local_irq_restore(flags);
897 	}
898 	return ret;
899 }
900 
901 static int rs_write_room(struct tty_struct *tty)
902 {
903 	struct serial_state *info = tty->driver_data;
904 
905 	if (serial_paranoia_check(info, tty->name, "rs_write_room"))
906 		return 0;
907 	return CIRC_SPACE(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
908 }
909 
910 static int rs_chars_in_buffer(struct tty_struct *tty)
911 {
912 	struct serial_state *info = tty->driver_data;
913 
914 	if (serial_paranoia_check(info, tty->name, "rs_chars_in_buffer"))
915 		return 0;
916 	return CIRC_CNT(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
917 }
918 
919 static void rs_flush_buffer(struct tty_struct *tty)
920 {
921 	struct serial_state *info = tty->driver_data;
922 	unsigned long flags;
923 
924 	if (serial_paranoia_check(info, tty->name, "rs_flush_buffer"))
925 		return;
926 	local_irq_save(flags);
927 	info->xmit.head = info->xmit.tail = 0;
928 	local_irq_restore(flags);
929 	tty_wakeup(tty);
930 }
931 
932 /*
933  * This function is used to send a high-priority XON/XOFF character to
934  * the device
935  */
936 static void rs_send_xchar(struct tty_struct *tty, char ch)
937 {
938 	struct serial_state *info = tty->driver_data;
939         unsigned long flags;
940 
941 	if (serial_paranoia_check(info, tty->name, "rs_send_char"))
942 		return;
943 
944 	info->x_char = ch;
945 	if (ch) {
946 		/* Make sure transmit interrupts are on */
947 
948 	        /* Check this ! */
949 	        local_irq_save(flags);
950 		if(!(custom.intenar & IF_TBE)) {
951 		    custom.intena = IF_SETCLR | IF_TBE;
952 		    mb();
953 		    /* set a pending Tx Interrupt, transmitter should restart now */
954 		    custom.intreq = IF_SETCLR | IF_TBE;
955 		    mb();
956 		}
957 		local_irq_restore(flags);
958 
959 		info->IER |= UART_IER_THRI;
960 	}
961 }
962 
963 /*
964  * ------------------------------------------------------------
965  * rs_throttle()
966  *
967  * This routine is called by the upper-layer tty layer to signal that
968  * incoming characters should be throttled.
969  * ------------------------------------------------------------
970  */
971 static void rs_throttle(struct tty_struct * tty)
972 {
973 	struct serial_state *info = tty->driver_data;
974 	unsigned long flags;
975 #ifdef SERIAL_DEBUG_THROTTLE
976 	char	buf[64];
977 
978 	printk("throttle %s: %d....\n", tty_name(tty, buf),
979 	       tty->ldisc.chars_in_buffer(tty));
980 #endif
981 
982 	if (serial_paranoia_check(info, tty->name, "rs_throttle"))
983 		return;
984 
985 	if (I_IXOFF(tty))
986 		rs_send_xchar(tty, STOP_CHAR(tty));
987 
988 	if (tty->termios->c_cflag & CRTSCTS)
989 		info->MCR &= ~SER_RTS;
990 
991 	local_irq_save(flags);
992 	rtsdtr_ctrl(info->MCR);
993 	local_irq_restore(flags);
994 }
995 
996 static void rs_unthrottle(struct tty_struct * tty)
997 {
998 	struct serial_state *info = tty->driver_data;
999 	unsigned long flags;
1000 #ifdef SERIAL_DEBUG_THROTTLE
1001 	char	buf[64];
1002 
1003 	printk("unthrottle %s: %d....\n", tty_name(tty, buf),
1004 	       tty->ldisc.chars_in_buffer(tty));
1005 #endif
1006 
1007 	if (serial_paranoia_check(info, tty->name, "rs_unthrottle"))
1008 		return;
1009 
1010 	if (I_IXOFF(tty)) {
1011 		if (info->x_char)
1012 			info->x_char = 0;
1013 		else
1014 			rs_send_xchar(tty, START_CHAR(tty));
1015 	}
1016 	if (tty->termios->c_cflag & CRTSCTS)
1017 		info->MCR |= SER_RTS;
1018 	local_irq_save(flags);
1019 	rtsdtr_ctrl(info->MCR);
1020 	local_irq_restore(flags);
1021 }
1022 
1023 /*
1024  * ------------------------------------------------------------
1025  * rs_ioctl() and friends
1026  * ------------------------------------------------------------
1027  */
1028 
1029 static int get_serial_info(struct tty_struct *tty, struct serial_state *state,
1030 			   struct serial_struct __user * retinfo)
1031 {
1032 	struct serial_struct tmp;
1033 
1034 	if (!retinfo)
1035 		return -EFAULT;
1036 	memset(&tmp, 0, sizeof(tmp));
1037 	tty_lock();
1038 	tmp.line = tty->index;
1039 	tmp.port = state->port;
1040 	tmp.flags = state->tport.flags;
1041 	tmp.xmit_fifo_size = state->xmit_fifo_size;
1042 	tmp.baud_base = state->baud_base;
1043 	tmp.close_delay = state->tport.close_delay;
1044 	tmp.closing_wait = state->tport.closing_wait;
1045 	tmp.custom_divisor = state->custom_divisor;
1046 	tty_unlock();
1047 	if (copy_to_user(retinfo,&tmp,sizeof(*retinfo)))
1048 		return -EFAULT;
1049 	return 0;
1050 }
1051 
1052 static int set_serial_info(struct tty_struct *tty, struct serial_state *state,
1053 			   struct serial_struct __user * new_info)
1054 {
1055 	struct tty_port *port = &state->tport;
1056 	struct serial_struct new_serial;
1057 	bool change_spd;
1058 	int 			retval = 0;
1059 
1060 	if (copy_from_user(&new_serial,new_info,sizeof(new_serial)))
1061 		return -EFAULT;
1062 
1063 	tty_lock();
1064 	change_spd = ((new_serial.flags ^ port->flags) & ASYNC_SPD_MASK) ||
1065 		new_serial.custom_divisor != state->custom_divisor;
1066 	if (new_serial.irq || new_serial.port != state->port ||
1067 			new_serial.xmit_fifo_size != state->xmit_fifo_size) {
1068 		tty_unlock();
1069 		return -EINVAL;
1070 	}
1071 
1072 	if (!serial_isroot()) {
1073 		if ((new_serial.baud_base != state->baud_base) ||
1074 		    (new_serial.close_delay != port->close_delay) ||
1075 		    (new_serial.xmit_fifo_size != state->xmit_fifo_size) ||
1076 		    ((new_serial.flags & ~ASYNC_USR_MASK) !=
1077 		     (port->flags & ~ASYNC_USR_MASK)))
1078 			return -EPERM;
1079 		port->flags = ((port->flags & ~ASYNC_USR_MASK) |
1080 			       (new_serial.flags & ASYNC_USR_MASK));
1081 		state->custom_divisor = new_serial.custom_divisor;
1082 		goto check_and_exit;
1083 	}
1084 
1085 	if (new_serial.baud_base < 9600) {
1086 		tty_unlock();
1087 		return -EINVAL;
1088 	}
1089 
1090 	/*
1091 	 * OK, past this point, all the error checking has been done.
1092 	 * At this point, we start making changes.....
1093 	 */
1094 
1095 	state->baud_base = new_serial.baud_base;
1096 	port->flags = ((port->flags & ~ASYNC_FLAGS) |
1097 			(new_serial.flags & ASYNC_FLAGS));
1098 	state->custom_divisor = new_serial.custom_divisor;
1099 	port->close_delay = new_serial.close_delay * HZ/100;
1100 	port->closing_wait = new_serial.closing_wait * HZ/100;
1101 	tty->low_latency = (port->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
1102 
1103 check_and_exit:
1104 	if (port->flags & ASYNC_INITIALIZED) {
1105 		if (change_spd) {
1106 			if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
1107 				tty->alt_speed = 57600;
1108 			if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
1109 				tty->alt_speed = 115200;
1110 			if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
1111 				tty->alt_speed = 230400;
1112 			if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
1113 				tty->alt_speed = 460800;
1114 			change_speed(tty, state, NULL);
1115 		}
1116 	} else
1117 		retval = startup(tty, state);
1118 	tty_unlock();
1119 	return retval;
1120 }
1121 
1122 
1123 /*
1124  * get_lsr_info - get line status register info
1125  *
1126  * Purpose: Let user call ioctl() to get info when the UART physically
1127  * 	    is emptied.  On bus types like RS485, the transmitter must
1128  * 	    release the bus after transmitting. This must be done when
1129  * 	    the transmit shift register is empty, not be done when the
1130  * 	    transmit holding register is empty.  This functionality
1131  * 	    allows an RS485 driver to be written in user space.
1132  */
1133 static int get_lsr_info(struct serial_state *info, unsigned int __user *value)
1134 {
1135 	unsigned char status;
1136 	unsigned int result;
1137 	unsigned long flags;
1138 
1139 	local_irq_save(flags);
1140 	status = custom.serdatr;
1141 	mb();
1142 	local_irq_restore(flags);
1143 	result = ((status & SDR_TSRE) ? TIOCSER_TEMT : 0);
1144 	if (copy_to_user(value, &result, sizeof(int)))
1145 		return -EFAULT;
1146 	return 0;
1147 }
1148 
1149 
1150 static int rs_tiocmget(struct tty_struct *tty)
1151 {
1152 	struct serial_state *info = tty->driver_data;
1153 	unsigned char control, status;
1154 	unsigned long flags;
1155 
1156 	if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
1157 		return -ENODEV;
1158 	if (tty->flags & (1 << TTY_IO_ERROR))
1159 		return -EIO;
1160 
1161 	control = info->MCR;
1162 	local_irq_save(flags);
1163 	status = ciab.pra;
1164 	local_irq_restore(flags);
1165 	return    ((control & SER_RTS) ? TIOCM_RTS : 0)
1166 		| ((control & SER_DTR) ? TIOCM_DTR : 0)
1167 		| (!(status  & SER_DCD) ? TIOCM_CAR : 0)
1168 		| (!(status  & SER_DSR) ? TIOCM_DSR : 0)
1169 		| (!(status  & SER_CTS) ? TIOCM_CTS : 0);
1170 }
1171 
1172 static int rs_tiocmset(struct tty_struct *tty, unsigned int set,
1173 						unsigned int clear)
1174 {
1175 	struct serial_state *info = tty->driver_data;
1176 	unsigned long flags;
1177 
1178 	if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
1179 		return -ENODEV;
1180 	if (tty->flags & (1 << TTY_IO_ERROR))
1181 		return -EIO;
1182 
1183 	local_irq_save(flags);
1184 	if (set & TIOCM_RTS)
1185 		info->MCR |= SER_RTS;
1186 	if (set & TIOCM_DTR)
1187 		info->MCR |= SER_DTR;
1188 	if (clear & TIOCM_RTS)
1189 		info->MCR &= ~SER_RTS;
1190 	if (clear & TIOCM_DTR)
1191 		info->MCR &= ~SER_DTR;
1192 	rtsdtr_ctrl(info->MCR);
1193 	local_irq_restore(flags);
1194 	return 0;
1195 }
1196 
1197 /*
1198  * rs_break() --- routine which turns the break handling on or off
1199  */
1200 static int rs_break(struct tty_struct *tty, int break_state)
1201 {
1202 	struct serial_state *info = tty->driver_data;
1203 	unsigned long flags;
1204 
1205 	if (serial_paranoia_check(info, tty->name, "rs_break"))
1206 		return -EINVAL;
1207 
1208 	local_irq_save(flags);
1209 	if (break_state == -1)
1210 	  custom.adkcon = AC_SETCLR | AC_UARTBRK;
1211 	else
1212 	  custom.adkcon = AC_UARTBRK;
1213 	mb();
1214 	local_irq_restore(flags);
1215 	return 0;
1216 }
1217 
1218 /*
1219  * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1220  * Return: write counters to the user passed counter struct
1221  * NB: both 1->0 and 0->1 transitions are counted except for
1222  *     RI where only 0->1 is counted.
1223  */
1224 static int rs_get_icount(struct tty_struct *tty,
1225 				struct serial_icounter_struct *icount)
1226 {
1227 	struct serial_state *info = tty->driver_data;
1228 	struct async_icount cnow;
1229 	unsigned long flags;
1230 
1231 	local_irq_save(flags);
1232 	cnow = info->icount;
1233 	local_irq_restore(flags);
1234 	icount->cts = cnow.cts;
1235 	icount->dsr = cnow.dsr;
1236 	icount->rng = cnow.rng;
1237 	icount->dcd = cnow.dcd;
1238 	icount->rx = cnow.rx;
1239 	icount->tx = cnow.tx;
1240 	icount->frame = cnow.frame;
1241 	icount->overrun = cnow.overrun;
1242 	icount->parity = cnow.parity;
1243 	icount->brk = cnow.brk;
1244 	icount->buf_overrun = cnow.buf_overrun;
1245 
1246 	return 0;
1247 }
1248 
1249 static int rs_ioctl(struct tty_struct *tty,
1250 		    unsigned int cmd, unsigned long arg)
1251 {
1252 	struct serial_state *info = tty->driver_data;
1253 	struct async_icount cprev, cnow;	/* kernel counter temps */
1254 	void __user *argp = (void __user *)arg;
1255 	unsigned long flags;
1256 
1257 	if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
1258 		return -ENODEV;
1259 
1260 	if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
1261 	    (cmd != TIOCSERCONFIG) && (cmd != TIOCSERGSTRUCT) &&
1262 	    (cmd != TIOCMIWAIT) && (cmd != TIOCGICOUNT)) {
1263 		if (tty->flags & (1 << TTY_IO_ERROR))
1264 		    return -EIO;
1265 	}
1266 
1267 	switch (cmd) {
1268 		case TIOCGSERIAL:
1269 			return get_serial_info(tty, info, argp);
1270 		case TIOCSSERIAL:
1271 			return set_serial_info(tty, info, argp);
1272 		case TIOCSERCONFIG:
1273 			return 0;
1274 
1275 		case TIOCSERGETLSR: /* Get line status register */
1276 			return get_lsr_info(info, argp);
1277 
1278 		case TIOCSERGSTRUCT:
1279 			if (copy_to_user(argp,
1280 					 info, sizeof(struct serial_state)))
1281 				return -EFAULT;
1282 			return 0;
1283 
1284 		/*
1285 		 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1286 		 * - mask passed in arg for lines of interest
1287  		 *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1288 		 * Caller should use TIOCGICOUNT to see which one it was
1289 		 */
1290 		case TIOCMIWAIT:
1291 			local_irq_save(flags);
1292 			/* note the counters on entry */
1293 			cprev = info->icount;
1294 			local_irq_restore(flags);
1295 			while (1) {
1296 				interruptible_sleep_on(&info->tport.delta_msr_wait);
1297 				/* see if a signal did it */
1298 				if (signal_pending(current))
1299 					return -ERESTARTSYS;
1300 				local_irq_save(flags);
1301 				cnow = info->icount; /* atomic copy */
1302 				local_irq_restore(flags);
1303 				if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
1304 				    cnow.dcd == cprev.dcd && cnow.cts == cprev.cts)
1305 					return -EIO; /* no change => error */
1306 				if ( ((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1307 				     ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1308 				     ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
1309 				     ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts)) ) {
1310 					return 0;
1311 				}
1312 				cprev = cnow;
1313 			}
1314 			/* NOTREACHED */
1315 
1316 		case TIOCSERGWILD:
1317 		case TIOCSERSWILD:
1318 			/* "setserial -W" is called in Debian boot */
1319 			printk ("TIOCSER?WILD ioctl obsolete, ignored.\n");
1320 			return 0;
1321 
1322 		default:
1323 			return -ENOIOCTLCMD;
1324 		}
1325 	return 0;
1326 }
1327 
1328 static void rs_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
1329 {
1330 	struct serial_state *info = tty->driver_data;
1331 	unsigned long flags;
1332 	unsigned int cflag = tty->termios->c_cflag;
1333 
1334 	change_speed(tty, info, old_termios);
1335 
1336 	/* Handle transition to B0 status */
1337 	if ((old_termios->c_cflag & CBAUD) &&
1338 	    !(cflag & CBAUD)) {
1339 		info->MCR &= ~(SER_DTR|SER_RTS);
1340 		local_irq_save(flags);
1341 		rtsdtr_ctrl(info->MCR);
1342 		local_irq_restore(flags);
1343 	}
1344 
1345 	/* Handle transition away from B0 status */
1346 	if (!(old_termios->c_cflag & CBAUD) &&
1347 	    (cflag & CBAUD)) {
1348 		info->MCR |= SER_DTR;
1349 		if (!(tty->termios->c_cflag & CRTSCTS) ||
1350 		    !test_bit(TTY_THROTTLED, &tty->flags)) {
1351 			info->MCR |= SER_RTS;
1352 		}
1353 		local_irq_save(flags);
1354 		rtsdtr_ctrl(info->MCR);
1355 		local_irq_restore(flags);
1356 	}
1357 
1358 	/* Handle turning off CRTSCTS */
1359 	if ((old_termios->c_cflag & CRTSCTS) &&
1360 	    !(tty->termios->c_cflag & CRTSCTS)) {
1361 		tty->hw_stopped = 0;
1362 		rs_start(tty);
1363 	}
1364 
1365 #if 0
1366 	/*
1367 	 * No need to wake up processes in open wait, since they
1368 	 * sample the CLOCAL flag once, and don't recheck it.
1369 	 * XXX  It's not clear whether the current behavior is correct
1370 	 * or not.  Hence, this may change.....
1371 	 */
1372 	if (!(old_termios->c_cflag & CLOCAL) &&
1373 	    (tty->termios->c_cflag & CLOCAL))
1374 		wake_up_interruptible(&info->open_wait);
1375 #endif
1376 }
1377 
1378 /*
1379  * ------------------------------------------------------------
1380  * rs_close()
1381  *
1382  * This routine is called when the serial port gets closed.  First, we
1383  * wait for the last remaining data to be sent.  Then, we unlink its
1384  * async structure from the interrupt chain if necessary, and we free
1385  * that IRQ if nothing is left in the chain.
1386  * ------------------------------------------------------------
1387  */
1388 static void rs_close(struct tty_struct *tty, struct file * filp)
1389 {
1390 	struct serial_state *state = tty->driver_data;
1391 	struct tty_port *port = &state->tport;
1392 
1393 	if (serial_paranoia_check(state, tty->name, "rs_close"))
1394 		return;
1395 
1396 	if (tty_port_close_start(port, tty, filp) == 0)
1397 		return;
1398 
1399 	/*
1400 	 * At this point we stop accepting input.  To do this, we
1401 	 * disable the receive line status interrupts, and tell the
1402 	 * interrupt driver to stop checking the data ready bit in the
1403 	 * line status register.
1404 	 */
1405 	state->read_status_mask &= ~UART_LSR_DR;
1406 	if (port->flags & ASYNC_INITIALIZED) {
1407 	        /* disable receive interrupts */
1408 	        custom.intena = IF_RBF;
1409 		mb();
1410 		/* clear any pending receive interrupt */
1411 		custom.intreq = IF_RBF;
1412 		mb();
1413 
1414 		/*
1415 		 * Before we drop DTR, make sure the UART transmitter
1416 		 * has completely drained; this is especially
1417 		 * important if there is a transmit FIFO!
1418 		 */
1419 		rs_wait_until_sent(tty, state->timeout);
1420 	}
1421 	shutdown(tty, state);
1422 	rs_flush_buffer(tty);
1423 
1424 	tty_ldisc_flush(tty);
1425 	port->tty = NULL;
1426 
1427 	tty_port_close_end(port, tty);
1428 }
1429 
1430 /*
1431  * rs_wait_until_sent() --- wait until the transmitter is empty
1432  */
1433 static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
1434 {
1435 	struct serial_state *info = tty->driver_data;
1436 	unsigned long orig_jiffies, char_time;
1437 	int lsr;
1438 
1439 	if (serial_paranoia_check(info, tty->name, "rs_wait_until_sent"))
1440 		return;
1441 
1442 	if (info->xmit_fifo_size == 0)
1443 		return; /* Just in case.... */
1444 
1445 	orig_jiffies = jiffies;
1446 
1447 	/*
1448 	 * Set the check interval to be 1/5 of the estimated time to
1449 	 * send a single character, and make it at least 1.  The check
1450 	 * interval should also be less than the timeout.
1451 	 *
1452 	 * Note: we have to use pretty tight timings here to satisfy
1453 	 * the NIST-PCTS.
1454 	 */
1455 	char_time = (info->timeout - HZ/50) / info->xmit_fifo_size;
1456 	char_time = char_time / 5;
1457 	if (char_time == 0)
1458 		char_time = 1;
1459 	if (timeout)
1460 	  char_time = min_t(unsigned long, char_time, timeout);
1461 	/*
1462 	 * If the transmitter hasn't cleared in twice the approximate
1463 	 * amount of time to send the entire FIFO, it probably won't
1464 	 * ever clear.  This assumes the UART isn't doing flow
1465 	 * control, which is currently the case.  Hence, if it ever
1466 	 * takes longer than info->timeout, this is probably due to a
1467 	 * UART bug of some kind.  So, we clamp the timeout parameter at
1468 	 * 2*info->timeout.
1469 	 */
1470 	if (!timeout || timeout > 2*info->timeout)
1471 		timeout = 2*info->timeout;
1472 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
1473 	printk("In rs_wait_until_sent(%d) check=%lu...", timeout, char_time);
1474 	printk("jiff=%lu...", jiffies);
1475 #endif
1476 	while(!((lsr = custom.serdatr) & SDR_TSRE)) {
1477 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
1478 		printk("serdatr = %d (jiff=%lu)...", lsr, jiffies);
1479 #endif
1480 		msleep_interruptible(jiffies_to_msecs(char_time));
1481 		if (signal_pending(current))
1482 			break;
1483 		if (timeout && time_after(jiffies, orig_jiffies + timeout))
1484 			break;
1485 	}
1486 	__set_current_state(TASK_RUNNING);
1487 
1488 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
1489 	printk("lsr = %d (jiff=%lu)...done\n", lsr, jiffies);
1490 #endif
1491 }
1492 
1493 /*
1494  * rs_hangup() --- called by tty_hangup() when a hangup is signaled.
1495  */
1496 static void rs_hangup(struct tty_struct *tty)
1497 {
1498 	struct serial_state *info = tty->driver_data;
1499 
1500 	if (serial_paranoia_check(info, tty->name, "rs_hangup"))
1501 		return;
1502 
1503 	rs_flush_buffer(tty);
1504 	shutdown(tty, info);
1505 	info->tport.count = 0;
1506 	info->tport.flags &= ~ASYNC_NORMAL_ACTIVE;
1507 	info->tport.tty = NULL;
1508 	wake_up_interruptible(&info->tport.open_wait);
1509 }
1510 
1511 /*
1512  * This routine is called whenever a serial port is opened.  It
1513  * enables interrupts for a serial port, linking in its async structure into
1514  * the IRQ chain.   It also performs the serial-specific
1515  * initialization for the tty structure.
1516  */
1517 static int rs_open(struct tty_struct *tty, struct file * filp)
1518 {
1519 	struct serial_state *info = rs_table + tty->index;
1520 	struct tty_port *port = &info->tport;
1521 	int retval;
1522 
1523 	port->count++;
1524 	port->tty = tty;
1525 	tty->driver_data = info;
1526 	tty->port = port;
1527 	if (serial_paranoia_check(info, tty->name, "rs_open"))
1528 		return -ENODEV;
1529 
1530 	tty->low_latency = (port->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
1531 
1532 	retval = startup(tty, info);
1533 	if (retval) {
1534 		return retval;
1535 	}
1536 
1537 	return tty_port_block_til_ready(port, tty, filp);
1538 }
1539 
1540 /*
1541  * /proc fs routines....
1542  */
1543 
1544 static inline void line_info(struct seq_file *m, int line,
1545 		struct serial_state *state)
1546 {
1547 	char	stat_buf[30], control, status;
1548 	unsigned long flags;
1549 
1550 	seq_printf(m, "%d: uart:amiga_builtin", line);
1551 
1552 	local_irq_save(flags);
1553 	status = ciab.pra;
1554 	control = (state->tport.flags & ASYNC_INITIALIZED) ? state->MCR : status;
1555 	local_irq_restore(flags);
1556 
1557 	stat_buf[0] = 0;
1558 	stat_buf[1] = 0;
1559 	if(!(control & SER_RTS))
1560 		strcat(stat_buf, "|RTS");
1561 	if(!(status & SER_CTS))
1562 		strcat(stat_buf, "|CTS");
1563 	if(!(control & SER_DTR))
1564 		strcat(stat_buf, "|DTR");
1565 	if(!(status & SER_DSR))
1566 		strcat(stat_buf, "|DSR");
1567 	if(!(status & SER_DCD))
1568 		strcat(stat_buf, "|CD");
1569 
1570 	if (state->quot)
1571 		seq_printf(m, " baud:%d", state->baud_base / state->quot);
1572 
1573 	seq_printf(m, " tx:%d rx:%d", state->icount.tx, state->icount.rx);
1574 
1575 	if (state->icount.frame)
1576 		seq_printf(m, " fe:%d", state->icount.frame);
1577 
1578 	if (state->icount.parity)
1579 		seq_printf(m, " pe:%d", state->icount.parity);
1580 
1581 	if (state->icount.brk)
1582 		seq_printf(m, " brk:%d", state->icount.brk);
1583 
1584 	if (state->icount.overrun)
1585 		seq_printf(m, " oe:%d", state->icount.overrun);
1586 
1587 	/*
1588 	 * Last thing is the RS-232 status lines
1589 	 */
1590 	seq_printf(m, " %s\n", stat_buf+1);
1591 }
1592 
1593 static int rs_proc_show(struct seq_file *m, void *v)
1594 {
1595 	seq_printf(m, "serinfo:1.0 driver:%s\n", serial_version);
1596 	line_info(m, 0, &rs_table[0]);
1597 	return 0;
1598 }
1599 
1600 static int rs_proc_open(struct inode *inode, struct file *file)
1601 {
1602 	return single_open(file, rs_proc_show, NULL);
1603 }
1604 
1605 static const struct file_operations rs_proc_fops = {
1606 	.owner		= THIS_MODULE,
1607 	.open		= rs_proc_open,
1608 	.read		= seq_read,
1609 	.llseek		= seq_lseek,
1610 	.release	= single_release,
1611 };
1612 
1613 /*
1614  * ---------------------------------------------------------------------
1615  * rs_init() and friends
1616  *
1617  * rs_init() is called at boot-time to initialize the serial driver.
1618  * ---------------------------------------------------------------------
1619  */
1620 
1621 /*
1622  * This routine prints out the appropriate serial driver version
1623  * number, and identifies which options were configured into this
1624  * driver.
1625  */
1626 static void show_serial_version(void)
1627 {
1628  	printk(KERN_INFO "%s version %s\n", serial_name, serial_version);
1629 }
1630 
1631 
1632 static const struct tty_operations serial_ops = {
1633 	.open = rs_open,
1634 	.close = rs_close,
1635 	.write = rs_write,
1636 	.put_char = rs_put_char,
1637 	.flush_chars = rs_flush_chars,
1638 	.write_room = rs_write_room,
1639 	.chars_in_buffer = rs_chars_in_buffer,
1640 	.flush_buffer = rs_flush_buffer,
1641 	.ioctl = rs_ioctl,
1642 	.throttle = rs_throttle,
1643 	.unthrottle = rs_unthrottle,
1644 	.set_termios = rs_set_termios,
1645 	.stop = rs_stop,
1646 	.start = rs_start,
1647 	.hangup = rs_hangup,
1648 	.break_ctl = rs_break,
1649 	.send_xchar = rs_send_xchar,
1650 	.wait_until_sent = rs_wait_until_sent,
1651 	.tiocmget = rs_tiocmget,
1652 	.tiocmset = rs_tiocmset,
1653 	.get_icount = rs_get_icount,
1654 	.proc_fops = &rs_proc_fops,
1655 };
1656 
1657 static int amiga_carrier_raised(struct tty_port *port)
1658 {
1659 	return !(ciab.pra & SER_DCD);
1660 }
1661 
1662 static void amiga_dtr_rts(struct tty_port *port, int raise)
1663 {
1664 	struct serial_state *info = container_of(port, struct serial_state,
1665 			tport);
1666 	unsigned long flags;
1667 
1668 	if (raise)
1669 		info->MCR |= SER_DTR|SER_RTS;
1670 	else
1671 		info->MCR &= ~(SER_DTR|SER_RTS);
1672 
1673 	local_irq_save(flags);
1674 	rtsdtr_ctrl(info->MCR);
1675 	local_irq_restore(flags);
1676 }
1677 
1678 static const struct tty_port_operations amiga_port_ops = {
1679 	.carrier_raised = amiga_carrier_raised,
1680 	.dtr_rts = amiga_dtr_rts,
1681 };
1682 
1683 /*
1684  * The serial driver boot-time initialization code!
1685  */
1686 static int __init amiga_serial_probe(struct platform_device *pdev)
1687 {
1688 	unsigned long flags;
1689 	struct serial_state * state;
1690 	int error;
1691 
1692 	serial_driver = alloc_tty_driver(NR_PORTS);
1693 	if (!serial_driver)
1694 		return -ENOMEM;
1695 
1696 	show_serial_version();
1697 
1698 	/* Initialize the tty_driver structure */
1699 
1700 	serial_driver->driver_name = "amiserial";
1701 	serial_driver->name = "ttyS";
1702 	serial_driver->major = TTY_MAJOR;
1703 	serial_driver->minor_start = 64;
1704 	serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
1705 	serial_driver->subtype = SERIAL_TYPE_NORMAL;
1706 	serial_driver->init_termios = tty_std_termios;
1707 	serial_driver->init_termios.c_cflag =
1708 		B9600 | CS8 | CREAD | HUPCL | CLOCAL;
1709 	serial_driver->flags = TTY_DRIVER_REAL_RAW;
1710 	tty_set_operations(serial_driver, &serial_ops);
1711 
1712 	error = tty_register_driver(serial_driver);
1713 	if (error)
1714 		goto fail_put_tty_driver;
1715 
1716 	state = rs_table;
1717 	state->port = (int)&custom.serdatr; /* Just to give it a value */
1718 	state->custom_divisor = 0;
1719 	state->icount.cts = state->icount.dsr =
1720 	  state->icount.rng = state->icount.dcd = 0;
1721 	state->icount.rx = state->icount.tx = 0;
1722 	state->icount.frame = state->icount.parity = 0;
1723 	state->icount.overrun = state->icount.brk = 0;
1724 	tty_port_init(&state->tport);
1725 	state->tport.ops = &amiga_port_ops;
1726 
1727 	printk(KERN_INFO "ttyS0 is the amiga builtin serial port\n");
1728 
1729 	/* Hardware set up */
1730 
1731 	state->baud_base = amiga_colorclock;
1732 	state->xmit_fifo_size = 1;
1733 
1734 	/* set ISRs, and then disable the rx interrupts */
1735 	error = request_irq(IRQ_AMIGA_TBE, ser_tx_int, 0, "serial TX", state);
1736 	if (error)
1737 		goto fail_unregister;
1738 
1739 	error = request_irq(IRQ_AMIGA_RBF, ser_rx_int, 0,
1740 			    "serial RX", state);
1741 	if (error)
1742 		goto fail_free_irq;
1743 
1744 	local_irq_save(flags);
1745 
1746 	/* turn off Rx and Tx interrupts */
1747 	custom.intena = IF_RBF | IF_TBE;
1748 	mb();
1749 
1750 	/* clear any pending interrupt */
1751 	custom.intreq = IF_RBF | IF_TBE;
1752 	mb();
1753 
1754 	local_irq_restore(flags);
1755 
1756 	/*
1757 	 * set the appropriate directions for the modem control flags,
1758 	 * and clear RTS and DTR
1759 	 */
1760 	ciab.ddra |= (SER_DTR | SER_RTS);   /* outputs */
1761 	ciab.ddra &= ~(SER_DCD | SER_CTS | SER_DSR);  /* inputs */
1762 
1763 	platform_set_drvdata(pdev, state);
1764 
1765 	return 0;
1766 
1767 fail_free_irq:
1768 	free_irq(IRQ_AMIGA_TBE, state);
1769 fail_unregister:
1770 	tty_unregister_driver(serial_driver);
1771 fail_put_tty_driver:
1772 	put_tty_driver(serial_driver);
1773 	return error;
1774 }
1775 
1776 static int __exit amiga_serial_remove(struct platform_device *pdev)
1777 {
1778 	int error;
1779 	struct serial_state *state = platform_get_drvdata(pdev);
1780 
1781 	/* printk("Unloading %s: version %s\n", serial_name, serial_version); */
1782 	if ((error = tty_unregister_driver(serial_driver)))
1783 		printk("SERIAL: failed to unregister serial driver (%d)\n",
1784 		       error);
1785 	put_tty_driver(serial_driver);
1786 
1787 	free_irq(IRQ_AMIGA_TBE, state);
1788 	free_irq(IRQ_AMIGA_RBF, state);
1789 
1790 	platform_set_drvdata(pdev, NULL);
1791 
1792 	return error;
1793 }
1794 
1795 static struct platform_driver amiga_serial_driver = {
1796 	.remove = __exit_p(amiga_serial_remove),
1797 	.driver   = {
1798 		.name	= "amiga-serial",
1799 		.owner	= THIS_MODULE,
1800 	},
1801 };
1802 
1803 static int __init amiga_serial_init(void)
1804 {
1805 	return platform_driver_probe(&amiga_serial_driver, amiga_serial_probe);
1806 }
1807 
1808 module_init(amiga_serial_init);
1809 
1810 static void __exit amiga_serial_exit(void)
1811 {
1812 	platform_driver_unregister(&amiga_serial_driver);
1813 }
1814 
1815 module_exit(amiga_serial_exit);
1816 
1817 
1818 #if defined(CONFIG_SERIAL_CONSOLE) && !defined(MODULE)
1819 
1820 /*
1821  * ------------------------------------------------------------
1822  * Serial console driver
1823  * ------------------------------------------------------------
1824  */
1825 
1826 static void amiga_serial_putc(char c)
1827 {
1828 	custom.serdat = (unsigned char)c | 0x100;
1829 	while (!(custom.serdatr & 0x2000))
1830 		barrier();
1831 }
1832 
1833 /*
1834  *	Print a string to the serial port trying not to disturb
1835  *	any possible real use of the port...
1836  *
1837  *	The console must be locked when we get here.
1838  */
1839 static void serial_console_write(struct console *co, const char *s,
1840 				unsigned count)
1841 {
1842 	unsigned short intena = custom.intenar;
1843 
1844 	custom.intena = IF_TBE;
1845 
1846 	while (count--) {
1847 		if (*s == '\n')
1848 			amiga_serial_putc('\r');
1849 		amiga_serial_putc(*s++);
1850 	}
1851 
1852 	custom.intena = IF_SETCLR | (intena & IF_TBE);
1853 }
1854 
1855 static struct tty_driver *serial_console_device(struct console *c, int *index)
1856 {
1857 	*index = 0;
1858 	return serial_driver;
1859 }
1860 
1861 static struct console sercons = {
1862 	.name =		"ttyS",
1863 	.write =	serial_console_write,
1864 	.device =	serial_console_device,
1865 	.flags =	CON_PRINTBUFFER,
1866 	.index =	-1,
1867 };
1868 
1869 /*
1870  *	Register console.
1871  */
1872 static int __init amiserial_console_init(void)
1873 {
1874 	register_console(&sercons);
1875 	return 0;
1876 }
1877 console_initcall(amiserial_console_init);
1878 
1879 #endif /* CONFIG_SERIAL_CONSOLE && !MODULE */
1880 
1881 MODULE_LICENSE("GPL");
1882 MODULE_ALIAS("platform:amiga-serial");
1883