xref: /linux/drivers/tty/amiserial.c (revision fbce3befd60d40639bf3c6b60f7477b2f988f92d)
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 
36 /* Set of debugging defines */
37 
38 #undef SERIAL_DEBUG_INTR
39 #undef SERIAL_DEBUG_OPEN
40 #undef SERIAL_DEBUG_FLOW
41 #undef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
42 
43 /* Sanity checks */
44 
45 #if defined(MODULE) && defined(SERIAL_DEBUG_MCOUNT)
46 #define DBG_CNT(s) printk("(%s): [%x] refc=%d, serc=%d, ttyc=%d -> %s\n", \
47  tty->name, (info->tport.flags), serial_driver->refcount,info->count,tty->count,s)
48 #else
49 #define DBG_CNT(s)
50 #endif
51 
52 /*
53  * End of serial driver configuration section.
54  */
55 
56 #include <linux/module.h>
57 
58 #include <linux/types.h>
59 #include <linux/serial.h>
60 #include <linux/serial_reg.h>
61 static char *serial_version = "4.30";
62 
63 #include <linux/errno.h>
64 #include <linux/signal.h>
65 #include <linux/sched.h>
66 #include <linux/kernel.h>
67 #include <linux/timer.h>
68 #include <linux/interrupt.h>
69 #include <linux/tty.h>
70 #include <linux/tty_flip.h>
71 #include <linux/circ_buf.h>
72 #include <linux/console.h>
73 #include <linux/major.h>
74 #include <linux/string.h>
75 #include <linux/fcntl.h>
76 #include <linux/ptrace.h>
77 #include <linux/ioport.h>
78 #include <linux/mm.h>
79 #include <linux/seq_file.h>
80 #include <linux/slab.h>
81 #include <linux/init.h>
82 #include <linux/bitops.h>
83 #include <linux/platform_device.h>
84 
85 #include <asm/setup.h>
86 
87 
88 #include <asm/irq.h>
89 
90 #include <asm/amigahw.h>
91 #include <asm/amigaints.h>
92 
93 struct serial_state {
94 	struct tty_port		tport;
95 	struct circ_buf		xmit;
96 	struct async_icount	icount;
97 
98 	unsigned long		port;
99 	int			baud_base;
100 	int			xmit_fifo_size;
101 	int			custom_divisor;
102 	int			read_status_mask;
103 	int			ignore_status_mask;
104 	int			timeout;
105 	int			quot;
106 	int			IER; 	/* Interrupt Enable Register */
107 	int			MCR; 	/* Modem control register */
108 	int			x_char;	/* xon/xoff character */
109 };
110 
111 #define custom amiga_custom
112 static char *serial_name = "Amiga-builtin serial driver";
113 
114 static struct tty_driver *serial_driver;
115 
116 /* number of characters left in xmit buffer before we ask for more */
117 #define WAKEUP_CHARS 256
118 
119 static unsigned char current_ctl_bits;
120 
121 static void change_speed(struct tty_struct *tty, struct serial_state *info,
122 		struct ktermios *old);
123 static void rs_wait_until_sent(struct tty_struct *tty, int timeout);
124 
125 
126 static struct serial_state rs_table[1];
127 
128 #define NR_PORTS ARRAY_SIZE(rs_table)
129 
130 #include <asm/uaccess.h>
131 
132 #define serial_isroot()	(capable(CAP_SYS_ADMIN))
133 
134 
135 static inline int serial_paranoia_check(struct serial_state *info,
136 					char *name, const char *routine)
137 {
138 #ifdef SERIAL_PARANOIA_CHECK
139 	static const char *badmagic =
140 		"Warning: bad magic number for serial struct (%s) in %s\n";
141 	static const char *badinfo =
142 		"Warning: null async_struct for (%s) in %s\n";
143 
144 	if (!info) {
145 		printk(badinfo, name, routine);
146 		return 1;
147 	}
148 	if (info->magic != SERIAL_MAGIC) {
149 		printk(badmagic, name, routine);
150 		return 1;
151 	}
152 #endif
153 	return 0;
154 }
155 
156 /* some serial hardware definitions */
157 #define SDR_OVRUN   (1<<15)
158 #define SDR_RBF     (1<<14)
159 #define SDR_TBE     (1<<13)
160 #define SDR_TSRE    (1<<12)
161 
162 #define SERPER_PARENB    (1<<15)
163 
164 #define AC_SETCLR   (1<<15)
165 #define AC_UARTBRK  (1<<11)
166 
167 #define SER_DTR     (1<<7)
168 #define SER_RTS     (1<<6)
169 #define SER_DCD     (1<<5)
170 #define SER_CTS     (1<<4)
171 #define SER_DSR     (1<<3)
172 
173 static __inline__ void rtsdtr_ctrl(int bits)
174 {
175     ciab.pra = ((bits & (SER_RTS | SER_DTR)) ^ (SER_RTS | SER_DTR)) | (ciab.pra & ~(SER_RTS | SER_DTR));
176 }
177 
178 /*
179  * ------------------------------------------------------------
180  * rs_stop() and rs_start()
181  *
182  * This routines are called before setting or resetting tty->stopped.
183  * They enable or disable transmitter interrupts, as necessary.
184  * ------------------------------------------------------------
185  */
186 static void rs_stop(struct tty_struct *tty)
187 {
188 	struct serial_state *info = tty->driver_data;
189 	unsigned long flags;
190 
191 	if (serial_paranoia_check(info, tty->name, "rs_stop"))
192 		return;
193 
194 	local_irq_save(flags);
195 	if (info->IER & UART_IER_THRI) {
196 		info->IER &= ~UART_IER_THRI;
197 		/* disable Tx interrupt and remove any pending interrupts */
198 		custom.intena = IF_TBE;
199 		mb();
200 		custom.intreq = IF_TBE;
201 		mb();
202 	}
203 	local_irq_restore(flags);
204 }
205 
206 static void rs_start(struct tty_struct *tty)
207 {
208 	struct serial_state *info = tty->driver_data;
209 	unsigned long flags;
210 
211 	if (serial_paranoia_check(info, tty->name, "rs_start"))
212 		return;
213 
214 	local_irq_save(flags);
215 	if (info->xmit.head != info->xmit.tail
216 	    && info->xmit.buf
217 	    && !(info->IER & UART_IER_THRI)) {
218 		info->IER |= UART_IER_THRI;
219 		custom.intena = IF_SETCLR | IF_TBE;
220 		mb();
221 		/* set a pending Tx Interrupt, transmitter should restart now */
222 		custom.intreq = IF_SETCLR | IF_TBE;
223 		mb();
224 	}
225 	local_irq_restore(flags);
226 }
227 
228 /*
229  * ----------------------------------------------------------------------
230  *
231  * Here starts the interrupt handling routines.  All of the following
232  * subroutines are declared as inline and are folded into
233  * rs_interrupt().  They were separated out for readability's sake.
234  *
235  * Note: rs_interrupt() is a "fast" interrupt, which means that it
236  * runs with interrupts turned off.  People who may want to modify
237  * rs_interrupt() should try to keep the interrupt handler as fast as
238  * possible.  After you are done making modifications, it is not a bad
239  * idea to do:
240  *
241  * gcc -S -DKERNEL -Wall -Wstrict-prototypes -O6 -fomit-frame-pointer serial.c
242  *
243  * and look at the resulting assemble code in serial.s.
244  *
245  * 				- Ted Ts'o (tytso@mit.edu), 7-Mar-93
246  * -----------------------------------------------------------------------
247  */
248 
249 static void receive_chars(struct serial_state *info)
250 {
251         int status;
252 	int serdatr;
253 	unsigned char ch, flag;
254 	struct	async_icount *icount;
255 	int oe = 0;
256 
257 	icount = &info->icount;
258 
259 	status = UART_LSR_DR; /* We obviously have a character! */
260 	serdatr = custom.serdatr;
261 	mb();
262 	custom.intreq = IF_RBF;
263 	mb();
264 
265 	if((serdatr & 0x1ff) == 0)
266 	    status |= UART_LSR_BI;
267 	if(serdatr & SDR_OVRUN)
268 	    status |= UART_LSR_OE;
269 
270 	ch = serdatr & 0xff;
271 	icount->rx++;
272 
273 #ifdef SERIAL_DEBUG_INTR
274 	printk("DR%02x:%02x...", ch, status);
275 #endif
276 	flag = TTY_NORMAL;
277 
278 	/*
279 	 * We don't handle parity or frame errors - but I have left
280 	 * the code in, since I'm not sure that the errors can't be
281 	 * detected.
282 	 */
283 
284 	if (status & (UART_LSR_BI | UART_LSR_PE |
285 		      UART_LSR_FE | UART_LSR_OE)) {
286 	  /*
287 	   * For statistics only
288 	   */
289 	  if (status & UART_LSR_BI) {
290 	    status &= ~(UART_LSR_FE | UART_LSR_PE);
291 	    icount->brk++;
292 	  } else if (status & UART_LSR_PE)
293 	    icount->parity++;
294 	  else if (status & UART_LSR_FE)
295 	    icount->frame++;
296 	  if (status & UART_LSR_OE)
297 	    icount->overrun++;
298 
299 	  /*
300 	   * Now check to see if character should be
301 	   * ignored, and mask off conditions which
302 	   * should be ignored.
303 	   */
304 	  if (status & info->ignore_status_mask)
305 	    goto out;
306 
307 	  status &= info->read_status_mask;
308 
309 	  if (status & (UART_LSR_BI)) {
310 #ifdef SERIAL_DEBUG_INTR
311 	    printk("handling break....");
312 #endif
313 	    flag = TTY_BREAK;
314 	    if (info->tport.flags & ASYNC_SAK)
315 	      do_SAK(info->tport.tty);
316 	  } else if (status & UART_LSR_PE)
317 	    flag = TTY_PARITY;
318 	  else if (status & UART_LSR_FE)
319 	    flag = TTY_FRAME;
320 	  if (status & UART_LSR_OE) {
321 	    /*
322 	     * Overrun is special, since it's
323 	     * reported immediately, and doesn't
324 	     * affect the current character
325 	     */
326 	     oe = 1;
327 	  }
328 	}
329 	tty_insert_flip_char(&info->tport, ch, flag);
330 	if (oe == 1)
331 		tty_insert_flip_char(&info->tport, 0, TTY_OVERRUN);
332 	tty_flip_buffer_push(&info->tport);
333 out:
334 	return;
335 }
336 
337 static void transmit_chars(struct serial_state *info)
338 {
339 	custom.intreq = IF_TBE;
340 	mb();
341 	if (info->x_char) {
342 	        custom.serdat = info->x_char | 0x100;
343 		mb();
344 		info->icount.tx++;
345 		info->x_char = 0;
346 		return;
347 	}
348 	if (info->xmit.head == info->xmit.tail
349 	    || info->tport.tty->stopped
350 	    || info->tport.tty->hw_stopped) {
351 		info->IER &= ~UART_IER_THRI;
352 	        custom.intena = IF_TBE;
353 		mb();
354 		return;
355 	}
356 
357 	custom.serdat = info->xmit.buf[info->xmit.tail++] | 0x100;
358 	mb();
359 	info->xmit.tail = info->xmit.tail & (SERIAL_XMIT_SIZE-1);
360 	info->icount.tx++;
361 
362 	if (CIRC_CNT(info->xmit.head,
363 		     info->xmit.tail,
364 		     SERIAL_XMIT_SIZE) < WAKEUP_CHARS)
365 		tty_wakeup(info->tport.tty);
366 
367 #ifdef SERIAL_DEBUG_INTR
368 	printk("THRE...");
369 #endif
370 	if (info->xmit.head == info->xmit.tail) {
371 	        custom.intena = IF_TBE;
372 		mb();
373 		info->IER &= ~UART_IER_THRI;
374 	}
375 }
376 
377 static void check_modem_status(struct serial_state *info)
378 {
379 	struct tty_port *port = &info->tport;
380 	unsigned char status = ciab.pra & (SER_DCD | SER_CTS | SER_DSR);
381 	unsigned char dstatus;
382 	struct	async_icount *icount;
383 
384 	/* Determine bits that have changed */
385 	dstatus = status ^ current_ctl_bits;
386 	current_ctl_bits = status;
387 
388 	if (dstatus) {
389 		icount = &info->icount;
390 		/* update input line counters */
391 		if (dstatus & SER_DSR)
392 			icount->dsr++;
393 		if (dstatus & SER_DCD) {
394 			icount->dcd++;
395 		}
396 		if (dstatus & SER_CTS)
397 			icount->cts++;
398 		wake_up_interruptible(&port->delta_msr_wait);
399 	}
400 
401 	if ((port->flags & ASYNC_CHECK_CD) && (dstatus & SER_DCD)) {
402 #if (defined(SERIAL_DEBUG_OPEN) || defined(SERIAL_DEBUG_INTR))
403 		printk("ttyS%d CD now %s...", info->line,
404 		       (!(status & SER_DCD)) ? "on" : "off");
405 #endif
406 		if (!(status & SER_DCD))
407 			wake_up_interruptible(&port->open_wait);
408 		else {
409 #ifdef SERIAL_DEBUG_OPEN
410 			printk("doing serial hangup...");
411 #endif
412 			if (port->tty)
413 				tty_hangup(port->tty);
414 		}
415 	}
416 	if (tty_port_cts_enabled(port)) {
417 		if (port->tty->hw_stopped) {
418 			if (!(status & SER_CTS)) {
419 #if (defined(SERIAL_DEBUG_INTR) || defined(SERIAL_DEBUG_FLOW))
420 				printk("CTS tx start...");
421 #endif
422 				port->tty->hw_stopped = 0;
423 				info->IER |= UART_IER_THRI;
424 				custom.intena = IF_SETCLR | IF_TBE;
425 				mb();
426 				/* set a pending Tx Interrupt, transmitter should restart now */
427 				custom.intreq = IF_SETCLR | IF_TBE;
428 				mb();
429 				tty_wakeup(port->tty);
430 				return;
431 			}
432 		} else {
433 			if ((status & SER_CTS)) {
434 #if (defined(SERIAL_DEBUG_INTR) || defined(SERIAL_DEBUG_FLOW))
435 				printk("CTS tx stop...");
436 #endif
437 				port->tty->hw_stopped = 1;
438 				info->IER &= ~UART_IER_THRI;
439 				/* disable Tx interrupt and remove any pending interrupts */
440 				custom.intena = IF_TBE;
441 				mb();
442 				custom.intreq = IF_TBE;
443 				mb();
444 			}
445 		}
446 	}
447 }
448 
449 static irqreturn_t ser_vbl_int( int irq, void *data)
450 {
451         /* vbl is just a periodic interrupt we tie into to update modem status */
452 	struct serial_state *info = data;
453 	/*
454 	 * TBD - is it better to unregister from this interrupt or to
455 	 * ignore it if MSI is clear ?
456 	 */
457 	if(info->IER & UART_IER_MSI)
458 	  check_modem_status(info);
459 	return IRQ_HANDLED;
460 }
461 
462 static irqreturn_t ser_rx_int(int irq, void *dev_id)
463 {
464 	struct serial_state *info = dev_id;
465 
466 #ifdef SERIAL_DEBUG_INTR
467 	printk("ser_rx_int...");
468 #endif
469 
470 	if (!info->tport.tty)
471 		return IRQ_NONE;
472 
473 	receive_chars(info);
474 #ifdef SERIAL_DEBUG_INTR
475 	printk("end.\n");
476 #endif
477 	return IRQ_HANDLED;
478 }
479 
480 static irqreturn_t ser_tx_int(int irq, void *dev_id)
481 {
482 	struct serial_state *info = dev_id;
483 
484 	if (custom.serdatr & SDR_TBE) {
485 #ifdef SERIAL_DEBUG_INTR
486 	  printk("ser_tx_int...");
487 #endif
488 
489 	  if (!info->tport.tty)
490 		return IRQ_NONE;
491 
492 	  transmit_chars(info);
493 #ifdef SERIAL_DEBUG_INTR
494 	  printk("end.\n");
495 #endif
496 	}
497 	return IRQ_HANDLED;
498 }
499 
500 /*
501  * -------------------------------------------------------------------
502  * Here ends the serial interrupt routines.
503  * -------------------------------------------------------------------
504  */
505 
506 /*
507  * ---------------------------------------------------------------
508  * Low level utility subroutines for the serial driver:  routines to
509  * figure out the appropriate timeout for an interrupt chain, routines
510  * to initialize and startup a serial port, and routines to shutdown a
511  * serial port.  Useful stuff like that.
512  * ---------------------------------------------------------------
513  */
514 
515 static int startup(struct tty_struct *tty, struct serial_state *info)
516 {
517 	struct tty_port *port = &info->tport;
518 	unsigned long flags;
519 	int	retval=0;
520 	unsigned long page;
521 
522 	page = get_zeroed_page(GFP_KERNEL);
523 	if (!page)
524 		return -ENOMEM;
525 
526 	local_irq_save(flags);
527 
528 	if (port->flags & ASYNC_INITIALIZED) {
529 		free_page(page);
530 		goto errout;
531 	}
532 
533 	if (info->xmit.buf)
534 		free_page(page);
535 	else
536 		info->xmit.buf = (unsigned char *) page;
537 
538 #ifdef SERIAL_DEBUG_OPEN
539 	printk("starting up ttys%d ...", info->line);
540 #endif
541 
542 	/* Clear anything in the input buffer */
543 
544 	custom.intreq = IF_RBF;
545 	mb();
546 
547 	retval = request_irq(IRQ_AMIGA_VERTB, ser_vbl_int, 0, "serial status", info);
548 	if (retval) {
549 	  if (serial_isroot()) {
550 	      set_bit(TTY_IO_ERROR, &tty->flags);
551 	    retval = 0;
552 	  }
553 	  goto errout;
554 	}
555 
556 	/* enable both Rx and Tx interrupts */
557 	custom.intena = IF_SETCLR | IF_RBF | IF_TBE;
558 	mb();
559 	info->IER = UART_IER_MSI;
560 
561 	/* remember current state of the DCD and CTS bits */
562 	current_ctl_bits = ciab.pra & (SER_DCD | SER_CTS | SER_DSR);
563 
564 	info->MCR = 0;
565 	if (C_BAUD(tty))
566 	  info->MCR = SER_DTR | SER_RTS;
567 	rtsdtr_ctrl(info->MCR);
568 
569 	clear_bit(TTY_IO_ERROR, &tty->flags);
570 	info->xmit.head = info->xmit.tail = 0;
571 
572 	/*
573 	 * Set up the tty->alt_speed kludge
574 	 */
575 	if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
576 		tty->alt_speed = 57600;
577 	if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
578 		tty->alt_speed = 115200;
579 	if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
580 		tty->alt_speed = 230400;
581 	if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
582 		tty->alt_speed = 460800;
583 
584 	/*
585 	 * and set the speed of the serial port
586 	 */
587 	change_speed(tty, info, NULL);
588 
589 	port->flags |= ASYNC_INITIALIZED;
590 	local_irq_restore(flags);
591 	return 0;
592 
593 errout:
594 	local_irq_restore(flags);
595 	return retval;
596 }
597 
598 /*
599  * This routine will shutdown a serial port; interrupts are disabled, and
600  * DTR is dropped if the hangup on close termio flag is on.
601  */
602 static void shutdown(struct tty_struct *tty, struct serial_state *info)
603 {
604 	unsigned long	flags;
605 	struct serial_state *state;
606 
607 	if (!(info->tport.flags & ASYNC_INITIALIZED))
608 		return;
609 
610 	state = info;
611 
612 #ifdef SERIAL_DEBUG_OPEN
613 	printk("Shutting down serial port %d ....\n", info->line);
614 #endif
615 
616 	local_irq_save(flags); /* Disable interrupts */
617 
618 	/*
619 	 * clear delta_msr_wait queue to avoid mem leaks: we may free the irq
620 	 * here so the queue might never be waken up
621 	 */
622 	wake_up_interruptible(&info->tport.delta_msr_wait);
623 
624 	/*
625 	 * Free the IRQ, if necessary
626 	 */
627 	free_irq(IRQ_AMIGA_VERTB, info);
628 
629 	if (info->xmit.buf) {
630 		free_page((unsigned long) info->xmit.buf);
631 		info->xmit.buf = NULL;
632 	}
633 
634 	info->IER = 0;
635 	custom.intena = IF_RBF | IF_TBE;
636 	mb();
637 
638 	/* disable break condition */
639 	custom.adkcon = AC_UARTBRK;
640 	mb();
641 
642 	if (C_HUPCL(tty))
643 		info->MCR &= ~(SER_DTR|SER_RTS);
644 	rtsdtr_ctrl(info->MCR);
645 
646 	set_bit(TTY_IO_ERROR, &tty->flags);
647 
648 	info->tport.flags &= ~ASYNC_INITIALIZED;
649 	local_irq_restore(flags);
650 }
651 
652 
653 /*
654  * This routine is called to set the UART divisor registers to match
655  * the specified baud rate for a serial port.
656  */
657 static void change_speed(struct tty_struct *tty, struct serial_state *info,
658 			 struct ktermios *old_termios)
659 {
660 	struct tty_port *port = &info->tport;
661 	int	quot = 0, baud_base, baud;
662 	unsigned cflag, cval = 0;
663 	int	bits;
664 	unsigned long	flags;
665 
666 	cflag = tty->termios.c_cflag;
667 
668 	/* Byte size is always 8 bits plus parity bit if requested */
669 
670 	cval = 3; bits = 10;
671 	if (cflag & CSTOPB) {
672 		cval |= 0x04;
673 		bits++;
674 	}
675 	if (cflag & PARENB) {
676 		cval |= UART_LCR_PARITY;
677 		bits++;
678 	}
679 	if (!(cflag & PARODD))
680 		cval |= UART_LCR_EPAR;
681 #ifdef CMSPAR
682 	if (cflag & CMSPAR)
683 		cval |= UART_LCR_SPAR;
684 #endif
685 
686 	/* Determine divisor based on baud rate */
687 	baud = tty_get_baud_rate(tty);
688 	if (!baud)
689 		baud = 9600;	/* B0 transition handled in rs_set_termios */
690 	baud_base = info->baud_base;
691 	if (baud == 38400 && (port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST)
692 		quot = info->custom_divisor;
693 	else {
694 		if (baud == 134)
695 			/* Special case since 134 is really 134.5 */
696 			quot = (2*baud_base / 269);
697 		else if (baud)
698 			quot = baud_base / baud;
699 	}
700 	/* If the quotient is zero refuse the change */
701 	if (!quot && old_termios) {
702 		/* FIXME: Will need updating for new tty in the end */
703 		tty->termios.c_cflag &= ~CBAUD;
704 		tty->termios.c_cflag |= (old_termios->c_cflag & CBAUD);
705 		baud = tty_get_baud_rate(tty);
706 		if (!baud)
707 			baud = 9600;
708 		if (baud == 38400 &&
709 		    (port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST)
710 			quot = info->custom_divisor;
711 		else {
712 			if (baud == 134)
713 				/* Special case since 134 is really 134.5 */
714 				quot = (2*baud_base / 269);
715 			else if (baud)
716 				quot = baud_base / baud;
717 		}
718 	}
719 	/* As a last resort, if the quotient is zero, default to 9600 bps */
720 	if (!quot)
721 		quot = baud_base / 9600;
722 	info->quot = quot;
723 	info->timeout = ((info->xmit_fifo_size*HZ*bits*quot) / baud_base);
724 	info->timeout += HZ/50;		/* Add .02 seconds of slop */
725 
726 	/* CTS flow control flag and modem status interrupts */
727 	info->IER &= ~UART_IER_MSI;
728 	if (port->flags & ASYNC_HARDPPS_CD)
729 		info->IER |= UART_IER_MSI;
730 	if (cflag & CRTSCTS) {
731 		port->flags |= ASYNC_CTS_FLOW;
732 		info->IER |= UART_IER_MSI;
733 	} else
734 		port->flags &= ~ASYNC_CTS_FLOW;
735 	if (cflag & CLOCAL)
736 		port->flags &= ~ASYNC_CHECK_CD;
737 	else {
738 		port->flags |= ASYNC_CHECK_CD;
739 		info->IER |= UART_IER_MSI;
740 	}
741 	/* TBD:
742 	 * Does clearing IER_MSI imply that we should disable the VBL interrupt ?
743 	 */
744 
745 	/*
746 	 * Set up parity check flag
747 	 */
748 
749 	info->read_status_mask = UART_LSR_OE | UART_LSR_DR;
750 	if (I_INPCK(tty))
751 		info->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
752 	if (I_BRKINT(tty) || I_PARMRK(tty))
753 		info->read_status_mask |= UART_LSR_BI;
754 
755 	/*
756 	 * Characters to ignore
757 	 */
758 	info->ignore_status_mask = 0;
759 	if (I_IGNPAR(tty))
760 		info->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
761 	if (I_IGNBRK(tty)) {
762 		info->ignore_status_mask |= UART_LSR_BI;
763 		/*
764 		 * If we're ignore parity and break indicators, ignore
765 		 * overruns too.  (For real raw support).
766 		 */
767 		if (I_IGNPAR(tty))
768 			info->ignore_status_mask |= UART_LSR_OE;
769 	}
770 	/*
771 	 * !!! ignore all characters if CREAD is not set
772 	 */
773 	if ((cflag & CREAD) == 0)
774 		info->ignore_status_mask |= UART_LSR_DR;
775 	local_irq_save(flags);
776 
777 	{
778 	  short serper;
779 
780 	/* Set up the baud rate */
781 	  serper = quot - 1;
782 
783 	/* Enable or disable parity bit */
784 
785 	if(cval & UART_LCR_PARITY)
786 	  serper |= (SERPER_PARENB);
787 
788 	custom.serper = serper;
789 	mb();
790 	}
791 
792 	local_irq_restore(flags);
793 }
794 
795 static int rs_put_char(struct tty_struct *tty, unsigned char ch)
796 {
797 	struct serial_state *info;
798 	unsigned long flags;
799 
800 	info = tty->driver_data;
801 
802 	if (serial_paranoia_check(info, tty->name, "rs_put_char"))
803 		return 0;
804 
805 	if (!info->xmit.buf)
806 		return 0;
807 
808 	local_irq_save(flags);
809 	if (CIRC_SPACE(info->xmit.head,
810 		       info->xmit.tail,
811 		       SERIAL_XMIT_SIZE) == 0) {
812 		local_irq_restore(flags);
813 		return 0;
814 	}
815 
816 	info->xmit.buf[info->xmit.head++] = ch;
817 	info->xmit.head &= SERIAL_XMIT_SIZE-1;
818 	local_irq_restore(flags);
819 	return 1;
820 }
821 
822 static void rs_flush_chars(struct tty_struct *tty)
823 {
824 	struct serial_state *info = tty->driver_data;
825 	unsigned long flags;
826 
827 	if (serial_paranoia_check(info, tty->name, "rs_flush_chars"))
828 		return;
829 
830 	if (info->xmit.head == info->xmit.tail
831 	    || tty->stopped
832 	    || tty->hw_stopped
833 	    || !info->xmit.buf)
834 		return;
835 
836 	local_irq_save(flags);
837 	info->IER |= UART_IER_THRI;
838 	custom.intena = IF_SETCLR | IF_TBE;
839 	mb();
840 	/* set a pending Tx Interrupt, transmitter should restart now */
841 	custom.intreq = IF_SETCLR | IF_TBE;
842 	mb();
843 	local_irq_restore(flags);
844 }
845 
846 static int rs_write(struct tty_struct * tty, const unsigned char *buf, int count)
847 {
848 	int	c, ret = 0;
849 	struct serial_state *info = tty->driver_data;
850 	unsigned long flags;
851 
852 	if (serial_paranoia_check(info, tty->name, "rs_write"))
853 		return 0;
854 
855 	if (!info->xmit.buf)
856 		return 0;
857 
858 	local_irq_save(flags);
859 	while (1) {
860 		c = CIRC_SPACE_TO_END(info->xmit.head,
861 				      info->xmit.tail,
862 				      SERIAL_XMIT_SIZE);
863 		if (count < c)
864 			c = count;
865 		if (c <= 0) {
866 			break;
867 		}
868 		memcpy(info->xmit.buf + info->xmit.head, buf, c);
869 		info->xmit.head = ((info->xmit.head + c) &
870 				   (SERIAL_XMIT_SIZE-1));
871 		buf += c;
872 		count -= c;
873 		ret += c;
874 	}
875 	local_irq_restore(flags);
876 
877 	if (info->xmit.head != info->xmit.tail
878 	    && !tty->stopped
879 	    && !tty->hw_stopped
880 	    && !(info->IER & UART_IER_THRI)) {
881 		info->IER |= UART_IER_THRI;
882 		local_irq_disable();
883 		custom.intena = IF_SETCLR | IF_TBE;
884 		mb();
885 		/* set a pending Tx Interrupt, transmitter should restart now */
886 		custom.intreq = IF_SETCLR | IF_TBE;
887 		mb();
888 		local_irq_restore(flags);
889 	}
890 	return ret;
891 }
892 
893 static int rs_write_room(struct tty_struct *tty)
894 {
895 	struct serial_state *info = tty->driver_data;
896 
897 	if (serial_paranoia_check(info, tty->name, "rs_write_room"))
898 		return 0;
899 	return CIRC_SPACE(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
900 }
901 
902 static int rs_chars_in_buffer(struct tty_struct *tty)
903 {
904 	struct serial_state *info = tty->driver_data;
905 
906 	if (serial_paranoia_check(info, tty->name, "rs_chars_in_buffer"))
907 		return 0;
908 	return CIRC_CNT(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
909 }
910 
911 static void rs_flush_buffer(struct tty_struct *tty)
912 {
913 	struct serial_state *info = tty->driver_data;
914 	unsigned long flags;
915 
916 	if (serial_paranoia_check(info, tty->name, "rs_flush_buffer"))
917 		return;
918 	local_irq_save(flags);
919 	info->xmit.head = info->xmit.tail = 0;
920 	local_irq_restore(flags);
921 	tty_wakeup(tty);
922 }
923 
924 /*
925  * This function is used to send a high-priority XON/XOFF character to
926  * the device
927  */
928 static void rs_send_xchar(struct tty_struct *tty, char ch)
929 {
930 	struct serial_state *info = tty->driver_data;
931         unsigned long flags;
932 
933 	if (serial_paranoia_check(info, tty->name, "rs_send_xchar"))
934 		return;
935 
936 	info->x_char = ch;
937 	if (ch) {
938 		/* Make sure transmit interrupts are on */
939 
940 	        /* Check this ! */
941 	        local_irq_save(flags);
942 		if(!(custom.intenar & IF_TBE)) {
943 		    custom.intena = IF_SETCLR | IF_TBE;
944 		    mb();
945 		    /* set a pending Tx Interrupt, transmitter should restart now */
946 		    custom.intreq = IF_SETCLR | IF_TBE;
947 		    mb();
948 		}
949 		local_irq_restore(flags);
950 
951 		info->IER |= UART_IER_THRI;
952 	}
953 }
954 
955 /*
956  * ------------------------------------------------------------
957  * rs_throttle()
958  *
959  * This routine is called by the upper-layer tty layer to signal that
960  * incoming characters should be throttled.
961  * ------------------------------------------------------------
962  */
963 static void rs_throttle(struct tty_struct * tty)
964 {
965 	struct serial_state *info = tty->driver_data;
966 	unsigned long flags;
967 #ifdef SERIAL_DEBUG_THROTTLE
968 	printk("throttle %s ....\n", tty_name(tty));
969 #endif
970 
971 	if (serial_paranoia_check(info, tty->name, "rs_throttle"))
972 		return;
973 
974 	if (I_IXOFF(tty))
975 		rs_send_xchar(tty, STOP_CHAR(tty));
976 
977 	if (C_CRTSCTS(tty))
978 		info->MCR &= ~SER_RTS;
979 
980 	local_irq_save(flags);
981 	rtsdtr_ctrl(info->MCR);
982 	local_irq_restore(flags);
983 }
984 
985 static void rs_unthrottle(struct tty_struct * tty)
986 {
987 	struct serial_state *info = tty->driver_data;
988 	unsigned long flags;
989 #ifdef SERIAL_DEBUG_THROTTLE
990 	printk("unthrottle %s ....\n", tty_name(tty));
991 #endif
992 
993 	if (serial_paranoia_check(info, tty->name, "rs_unthrottle"))
994 		return;
995 
996 	if (I_IXOFF(tty)) {
997 		if (info->x_char)
998 			info->x_char = 0;
999 		else
1000 			rs_send_xchar(tty, START_CHAR(tty));
1001 	}
1002 	if (C_CRTSCTS(tty))
1003 		info->MCR |= SER_RTS;
1004 	local_irq_save(flags);
1005 	rtsdtr_ctrl(info->MCR);
1006 	local_irq_restore(flags);
1007 }
1008 
1009 /*
1010  * ------------------------------------------------------------
1011  * rs_ioctl() and friends
1012  * ------------------------------------------------------------
1013  */
1014 
1015 static int get_serial_info(struct tty_struct *tty, struct serial_state *state,
1016 			   struct serial_struct __user * retinfo)
1017 {
1018 	struct serial_struct tmp;
1019 
1020 	if (!retinfo)
1021 		return -EFAULT;
1022 	memset(&tmp, 0, sizeof(tmp));
1023 	tty_lock(tty);
1024 	tmp.line = tty->index;
1025 	tmp.port = state->port;
1026 	tmp.flags = state->tport.flags;
1027 	tmp.xmit_fifo_size = state->xmit_fifo_size;
1028 	tmp.baud_base = state->baud_base;
1029 	tmp.close_delay = state->tport.close_delay;
1030 	tmp.closing_wait = state->tport.closing_wait;
1031 	tmp.custom_divisor = state->custom_divisor;
1032 	tty_unlock(tty);
1033 	if (copy_to_user(retinfo,&tmp,sizeof(*retinfo)))
1034 		return -EFAULT;
1035 	return 0;
1036 }
1037 
1038 static int set_serial_info(struct tty_struct *tty, struct serial_state *state,
1039 			   struct serial_struct __user * new_info)
1040 {
1041 	struct tty_port *port = &state->tport;
1042 	struct serial_struct new_serial;
1043 	bool change_spd;
1044 	int 			retval = 0;
1045 
1046 	if (copy_from_user(&new_serial,new_info,sizeof(new_serial)))
1047 		return -EFAULT;
1048 
1049 	tty_lock(tty);
1050 	change_spd = ((new_serial.flags ^ port->flags) & ASYNC_SPD_MASK) ||
1051 		new_serial.custom_divisor != state->custom_divisor;
1052 	if (new_serial.irq || new_serial.port != state->port ||
1053 			new_serial.xmit_fifo_size != state->xmit_fifo_size) {
1054 		tty_unlock(tty);
1055 		return -EINVAL;
1056 	}
1057 
1058 	if (!serial_isroot()) {
1059 		if ((new_serial.baud_base != state->baud_base) ||
1060 		    (new_serial.close_delay != port->close_delay) ||
1061 		    (new_serial.xmit_fifo_size != state->xmit_fifo_size) ||
1062 		    ((new_serial.flags & ~ASYNC_USR_MASK) !=
1063 		     (port->flags & ~ASYNC_USR_MASK))) {
1064 			tty_unlock(tty);
1065 			return -EPERM;
1066 		}
1067 		port->flags = ((port->flags & ~ASYNC_USR_MASK) |
1068 			       (new_serial.flags & ASYNC_USR_MASK));
1069 		state->custom_divisor = new_serial.custom_divisor;
1070 		goto check_and_exit;
1071 	}
1072 
1073 	if (new_serial.baud_base < 9600) {
1074 		tty_unlock(tty);
1075 		return -EINVAL;
1076 	}
1077 
1078 	/*
1079 	 * OK, past this point, all the error checking has been done.
1080 	 * At this point, we start making changes.....
1081 	 */
1082 
1083 	state->baud_base = new_serial.baud_base;
1084 	port->flags = ((port->flags & ~ASYNC_FLAGS) |
1085 			(new_serial.flags & ASYNC_FLAGS));
1086 	state->custom_divisor = new_serial.custom_divisor;
1087 	port->close_delay = new_serial.close_delay * HZ/100;
1088 	port->closing_wait = new_serial.closing_wait * HZ/100;
1089 	port->low_latency = (port->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
1090 
1091 check_and_exit:
1092 	if (port->flags & ASYNC_INITIALIZED) {
1093 		if (change_spd) {
1094 			if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
1095 				tty->alt_speed = 57600;
1096 			if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
1097 				tty->alt_speed = 115200;
1098 			if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
1099 				tty->alt_speed = 230400;
1100 			if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
1101 				tty->alt_speed = 460800;
1102 			change_speed(tty, state, NULL);
1103 		}
1104 	} else
1105 		retval = startup(tty, state);
1106 	tty_unlock(tty);
1107 	return retval;
1108 }
1109 
1110 
1111 /*
1112  * get_lsr_info - get line status register info
1113  *
1114  * Purpose: Let user call ioctl() to get info when the UART physically
1115  * 	    is emptied.  On bus types like RS485, the transmitter must
1116  * 	    release the bus after transmitting. This must be done when
1117  * 	    the transmit shift register is empty, not be done when the
1118  * 	    transmit holding register is empty.  This functionality
1119  * 	    allows an RS485 driver to be written in user space.
1120  */
1121 static int get_lsr_info(struct serial_state *info, unsigned int __user *value)
1122 {
1123 	unsigned char status;
1124 	unsigned int result;
1125 	unsigned long flags;
1126 
1127 	local_irq_save(flags);
1128 	status = custom.serdatr;
1129 	mb();
1130 	local_irq_restore(flags);
1131 	result = ((status & SDR_TSRE) ? TIOCSER_TEMT : 0);
1132 	if (copy_to_user(value, &result, sizeof(int)))
1133 		return -EFAULT;
1134 	return 0;
1135 }
1136 
1137 
1138 static int rs_tiocmget(struct tty_struct *tty)
1139 {
1140 	struct serial_state *info = tty->driver_data;
1141 	unsigned char control, status;
1142 	unsigned long flags;
1143 
1144 	if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
1145 		return -ENODEV;
1146 	if (tty->flags & (1 << TTY_IO_ERROR))
1147 		return -EIO;
1148 
1149 	control = info->MCR;
1150 	local_irq_save(flags);
1151 	status = ciab.pra;
1152 	local_irq_restore(flags);
1153 	return    ((control & SER_RTS) ? TIOCM_RTS : 0)
1154 		| ((control & SER_DTR) ? TIOCM_DTR : 0)
1155 		| (!(status  & SER_DCD) ? TIOCM_CAR : 0)
1156 		| (!(status  & SER_DSR) ? TIOCM_DSR : 0)
1157 		| (!(status  & SER_CTS) ? TIOCM_CTS : 0);
1158 }
1159 
1160 static int rs_tiocmset(struct tty_struct *tty, unsigned int set,
1161 						unsigned int clear)
1162 {
1163 	struct serial_state *info = tty->driver_data;
1164 	unsigned long flags;
1165 
1166 	if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
1167 		return -ENODEV;
1168 	if (tty->flags & (1 << TTY_IO_ERROR))
1169 		return -EIO;
1170 
1171 	local_irq_save(flags);
1172 	if (set & TIOCM_RTS)
1173 		info->MCR |= SER_RTS;
1174 	if (set & TIOCM_DTR)
1175 		info->MCR |= SER_DTR;
1176 	if (clear & TIOCM_RTS)
1177 		info->MCR &= ~SER_RTS;
1178 	if (clear & TIOCM_DTR)
1179 		info->MCR &= ~SER_DTR;
1180 	rtsdtr_ctrl(info->MCR);
1181 	local_irq_restore(flags);
1182 	return 0;
1183 }
1184 
1185 /*
1186  * rs_break() --- routine which turns the break handling on or off
1187  */
1188 static int rs_break(struct tty_struct *tty, int break_state)
1189 {
1190 	struct serial_state *info = tty->driver_data;
1191 	unsigned long flags;
1192 
1193 	if (serial_paranoia_check(info, tty->name, "rs_break"))
1194 		return -EINVAL;
1195 
1196 	local_irq_save(flags);
1197 	if (break_state == -1)
1198 	  custom.adkcon = AC_SETCLR | AC_UARTBRK;
1199 	else
1200 	  custom.adkcon = AC_UARTBRK;
1201 	mb();
1202 	local_irq_restore(flags);
1203 	return 0;
1204 }
1205 
1206 /*
1207  * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1208  * Return: write counters to the user passed counter struct
1209  * NB: both 1->0 and 0->1 transitions are counted except for
1210  *     RI where only 0->1 is counted.
1211  */
1212 static int rs_get_icount(struct tty_struct *tty,
1213 				struct serial_icounter_struct *icount)
1214 {
1215 	struct serial_state *info = tty->driver_data;
1216 	struct async_icount cnow;
1217 	unsigned long flags;
1218 
1219 	local_irq_save(flags);
1220 	cnow = info->icount;
1221 	local_irq_restore(flags);
1222 	icount->cts = cnow.cts;
1223 	icount->dsr = cnow.dsr;
1224 	icount->rng = cnow.rng;
1225 	icount->dcd = cnow.dcd;
1226 	icount->rx = cnow.rx;
1227 	icount->tx = cnow.tx;
1228 	icount->frame = cnow.frame;
1229 	icount->overrun = cnow.overrun;
1230 	icount->parity = cnow.parity;
1231 	icount->brk = cnow.brk;
1232 	icount->buf_overrun = cnow.buf_overrun;
1233 
1234 	return 0;
1235 }
1236 
1237 static int rs_ioctl(struct tty_struct *tty,
1238 		    unsigned int cmd, unsigned long arg)
1239 {
1240 	struct serial_state *info = tty->driver_data;
1241 	struct async_icount cprev, cnow;	/* kernel counter temps */
1242 	void __user *argp = (void __user *)arg;
1243 	unsigned long flags;
1244 	DEFINE_WAIT(wait);
1245 	int ret;
1246 
1247 	if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
1248 		return -ENODEV;
1249 
1250 	if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
1251 	    (cmd != TIOCSERCONFIG) && (cmd != TIOCSERGSTRUCT) &&
1252 	    (cmd != TIOCMIWAIT) && (cmd != TIOCGICOUNT)) {
1253 		if (tty->flags & (1 << TTY_IO_ERROR))
1254 		    return -EIO;
1255 	}
1256 
1257 	switch (cmd) {
1258 		case TIOCGSERIAL:
1259 			return get_serial_info(tty, info, argp);
1260 		case TIOCSSERIAL:
1261 			return set_serial_info(tty, info, argp);
1262 		case TIOCSERCONFIG:
1263 			return 0;
1264 
1265 		case TIOCSERGETLSR: /* Get line status register */
1266 			return get_lsr_info(info, argp);
1267 
1268 		case TIOCSERGSTRUCT:
1269 			if (copy_to_user(argp,
1270 					 info, sizeof(struct serial_state)))
1271 				return -EFAULT;
1272 			return 0;
1273 
1274 		/*
1275 		 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1276 		 * - mask passed in arg for lines of interest
1277  		 *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1278 		 * Caller should use TIOCGICOUNT to see which one it was
1279 		 */
1280 		case TIOCMIWAIT:
1281 			local_irq_save(flags);
1282 			/* note the counters on entry */
1283 			cprev = info->icount;
1284 			local_irq_restore(flags);
1285 			while (1) {
1286 				prepare_to_wait(&info->tport.delta_msr_wait,
1287 						&wait, TASK_INTERRUPTIBLE);
1288 				local_irq_save(flags);
1289 				cnow = info->icount; /* atomic copy */
1290 				local_irq_restore(flags);
1291 				if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
1292 				    cnow.dcd == cprev.dcd && cnow.cts == cprev.cts) {
1293 					ret = -EIO; /* no change => error */
1294 					break;
1295 				}
1296 				if ( ((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1297 				     ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1298 				     ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
1299 				     ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts)) ) {
1300 					ret = 0;
1301 					break;
1302 				}
1303 				schedule();
1304 				/* see if a signal did it */
1305 				if (signal_pending(current)) {
1306 					ret = -ERESTARTSYS;
1307 					break;
1308 				}
1309 				cprev = cnow;
1310 			}
1311 			finish_wait(&info->tport.delta_msr_wait, &wait);
1312 			return ret;
1313 
1314 		case TIOCSERGWILD:
1315 		case TIOCSERSWILD:
1316 			/* "setserial -W" is called in Debian boot */
1317 			printk ("TIOCSER?WILD ioctl obsolete, ignored.\n");
1318 			return 0;
1319 
1320 		default:
1321 			return -ENOIOCTLCMD;
1322 		}
1323 	return 0;
1324 }
1325 
1326 static void rs_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
1327 {
1328 	struct serial_state *info = tty->driver_data;
1329 	unsigned long flags;
1330 	unsigned int cflag = tty->termios.c_cflag;
1331 
1332 	change_speed(tty, info, old_termios);
1333 
1334 	/* Handle transition to B0 status */
1335 	if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD)) {
1336 		info->MCR &= ~(SER_DTR|SER_RTS);
1337 		local_irq_save(flags);
1338 		rtsdtr_ctrl(info->MCR);
1339 		local_irq_restore(flags);
1340 	}
1341 
1342 	/* Handle transition away from B0 status */
1343 	if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1344 		info->MCR |= SER_DTR;
1345 		if (!C_CRTSCTS(tty) || !test_bit(TTY_THROTTLED, &tty->flags))
1346 			info->MCR |= SER_RTS;
1347 		local_irq_save(flags);
1348 		rtsdtr_ctrl(info->MCR);
1349 		local_irq_restore(flags);
1350 	}
1351 
1352 	/* Handle turning off CRTSCTS */
1353 	if ((old_termios->c_cflag & CRTSCTS) && !C_CRTSCTS(tty)) {
1354 		tty->hw_stopped = 0;
1355 		rs_start(tty);
1356 	}
1357 
1358 #if 0
1359 	/*
1360 	 * No need to wake up processes in open wait, since they
1361 	 * sample the CLOCAL flag once, and don't recheck it.
1362 	 * XXX  It's not clear whether the current behavior is correct
1363 	 * or not.  Hence, this may change.....
1364 	 */
1365 	if (!(old_termios->c_cflag & CLOCAL) && C_CLOCAL(tty))
1366 		wake_up_interruptible(&info->open_wait);
1367 #endif
1368 }
1369 
1370 /*
1371  * ------------------------------------------------------------
1372  * rs_close()
1373  *
1374  * This routine is called when the serial port gets closed.  First, we
1375  * wait for the last remaining data to be sent.  Then, we unlink its
1376  * async structure from the interrupt chain if necessary, and we free
1377  * that IRQ if nothing is left in the chain.
1378  * ------------------------------------------------------------
1379  */
1380 static void rs_close(struct tty_struct *tty, struct file * filp)
1381 {
1382 	struct serial_state *state = tty->driver_data;
1383 	struct tty_port *port = &state->tport;
1384 
1385 	if (serial_paranoia_check(state, tty->name, "rs_close"))
1386 		return;
1387 
1388 	if (tty_port_close_start(port, tty, filp) == 0)
1389 		return;
1390 
1391 	/*
1392 	 * At this point we stop accepting input.  To do this, we
1393 	 * disable the receive line status interrupts, and tell the
1394 	 * interrupt driver to stop checking the data ready bit in the
1395 	 * line status register.
1396 	 */
1397 	state->read_status_mask &= ~UART_LSR_DR;
1398 	if (port->flags & ASYNC_INITIALIZED) {
1399 	        /* disable receive interrupts */
1400 	        custom.intena = IF_RBF;
1401 		mb();
1402 		/* clear any pending receive interrupt */
1403 		custom.intreq = IF_RBF;
1404 		mb();
1405 
1406 		/*
1407 		 * Before we drop DTR, make sure the UART transmitter
1408 		 * has completely drained; this is especially
1409 		 * important if there is a transmit FIFO!
1410 		 */
1411 		rs_wait_until_sent(tty, state->timeout);
1412 	}
1413 	shutdown(tty, state);
1414 	rs_flush_buffer(tty);
1415 
1416 	tty_ldisc_flush(tty);
1417 	port->tty = NULL;
1418 
1419 	tty_port_close_end(port, tty);
1420 }
1421 
1422 /*
1423  * rs_wait_until_sent() --- wait until the transmitter is empty
1424  */
1425 static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
1426 {
1427 	struct serial_state *info = tty->driver_data;
1428 	unsigned long orig_jiffies, char_time;
1429 	int lsr;
1430 
1431 	if (serial_paranoia_check(info, tty->name, "rs_wait_until_sent"))
1432 		return;
1433 
1434 	if (info->xmit_fifo_size == 0)
1435 		return; /* Just in case.... */
1436 
1437 	orig_jiffies = jiffies;
1438 
1439 	/*
1440 	 * Set the check interval to be 1/5 of the estimated time to
1441 	 * send a single character, and make it at least 1.  The check
1442 	 * interval should also be less than the timeout.
1443 	 *
1444 	 * Note: we have to use pretty tight timings here to satisfy
1445 	 * the NIST-PCTS.
1446 	 */
1447 	char_time = (info->timeout - HZ/50) / info->xmit_fifo_size;
1448 	char_time = char_time / 5;
1449 	if (char_time == 0)
1450 		char_time = 1;
1451 	if (timeout)
1452 	  char_time = min_t(unsigned long, char_time, timeout);
1453 	/*
1454 	 * If the transmitter hasn't cleared in twice the approximate
1455 	 * amount of time to send the entire FIFO, it probably won't
1456 	 * ever clear.  This assumes the UART isn't doing flow
1457 	 * control, which is currently the case.  Hence, if it ever
1458 	 * takes longer than info->timeout, this is probably due to a
1459 	 * UART bug of some kind.  So, we clamp the timeout parameter at
1460 	 * 2*info->timeout.
1461 	 */
1462 	if (!timeout || timeout > 2*info->timeout)
1463 		timeout = 2*info->timeout;
1464 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
1465 	printk("In rs_wait_until_sent(%d) check=%lu...", timeout, char_time);
1466 	printk("jiff=%lu...", jiffies);
1467 #endif
1468 	while(!((lsr = custom.serdatr) & SDR_TSRE)) {
1469 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
1470 		printk("serdatr = %d (jiff=%lu)...", lsr, jiffies);
1471 #endif
1472 		msleep_interruptible(jiffies_to_msecs(char_time));
1473 		if (signal_pending(current))
1474 			break;
1475 		if (timeout && time_after(jiffies, orig_jiffies + timeout))
1476 			break;
1477 	}
1478 	__set_current_state(TASK_RUNNING);
1479 
1480 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
1481 	printk("lsr = %d (jiff=%lu)...done\n", lsr, jiffies);
1482 #endif
1483 }
1484 
1485 /*
1486  * rs_hangup() --- called by tty_hangup() when a hangup is signaled.
1487  */
1488 static void rs_hangup(struct tty_struct *tty)
1489 {
1490 	struct serial_state *info = tty->driver_data;
1491 
1492 	if (serial_paranoia_check(info, tty->name, "rs_hangup"))
1493 		return;
1494 
1495 	rs_flush_buffer(tty);
1496 	shutdown(tty, info);
1497 	info->tport.count = 0;
1498 	info->tport.flags &= ~ASYNC_NORMAL_ACTIVE;
1499 	info->tport.tty = NULL;
1500 	wake_up_interruptible(&info->tport.open_wait);
1501 }
1502 
1503 /*
1504  * This routine is called whenever a serial port is opened.  It
1505  * enables interrupts for a serial port, linking in its async structure into
1506  * the IRQ chain.   It also performs the serial-specific
1507  * initialization for the tty structure.
1508  */
1509 static int rs_open(struct tty_struct *tty, struct file * filp)
1510 {
1511 	struct serial_state *info = rs_table + tty->index;
1512 	struct tty_port *port = &info->tport;
1513 	int retval;
1514 
1515 	port->count++;
1516 	port->tty = tty;
1517 	tty->driver_data = info;
1518 	tty->port = port;
1519 	if (serial_paranoia_check(info, tty->name, "rs_open"))
1520 		return -ENODEV;
1521 
1522 	port->low_latency = (port->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
1523 
1524 	retval = startup(tty, info);
1525 	if (retval) {
1526 		return retval;
1527 	}
1528 
1529 	return tty_port_block_til_ready(port, tty, filp);
1530 }
1531 
1532 /*
1533  * /proc fs routines....
1534  */
1535 
1536 static inline void line_info(struct seq_file *m, int line,
1537 		struct serial_state *state)
1538 {
1539 	char	stat_buf[30], control, status;
1540 	unsigned long flags;
1541 
1542 	seq_printf(m, "%d: uart:amiga_builtin", line);
1543 
1544 	local_irq_save(flags);
1545 	status = ciab.pra;
1546 	control = (state->tport.flags & ASYNC_INITIALIZED) ? state->MCR : status;
1547 	local_irq_restore(flags);
1548 
1549 	stat_buf[0] = 0;
1550 	stat_buf[1] = 0;
1551 	if(!(control & SER_RTS))
1552 		strcat(stat_buf, "|RTS");
1553 	if(!(status & SER_CTS))
1554 		strcat(stat_buf, "|CTS");
1555 	if(!(control & SER_DTR))
1556 		strcat(stat_buf, "|DTR");
1557 	if(!(status & SER_DSR))
1558 		strcat(stat_buf, "|DSR");
1559 	if(!(status & SER_DCD))
1560 		strcat(stat_buf, "|CD");
1561 
1562 	if (state->quot)
1563 		seq_printf(m, " baud:%d", state->baud_base / state->quot);
1564 
1565 	seq_printf(m, " tx:%d rx:%d", state->icount.tx, state->icount.rx);
1566 
1567 	if (state->icount.frame)
1568 		seq_printf(m, " fe:%d", state->icount.frame);
1569 
1570 	if (state->icount.parity)
1571 		seq_printf(m, " pe:%d", state->icount.parity);
1572 
1573 	if (state->icount.brk)
1574 		seq_printf(m, " brk:%d", state->icount.brk);
1575 
1576 	if (state->icount.overrun)
1577 		seq_printf(m, " oe:%d", state->icount.overrun);
1578 
1579 	/*
1580 	 * Last thing is the RS-232 status lines
1581 	 */
1582 	seq_printf(m, " %s\n", stat_buf+1);
1583 }
1584 
1585 static int rs_proc_show(struct seq_file *m, void *v)
1586 {
1587 	seq_printf(m, "serinfo:1.0 driver:%s\n", serial_version);
1588 	line_info(m, 0, &rs_table[0]);
1589 	return 0;
1590 }
1591 
1592 static int rs_proc_open(struct inode *inode, struct file *file)
1593 {
1594 	return single_open(file, rs_proc_show, NULL);
1595 }
1596 
1597 static const struct file_operations rs_proc_fops = {
1598 	.owner		= THIS_MODULE,
1599 	.open		= rs_proc_open,
1600 	.read		= seq_read,
1601 	.llseek		= seq_lseek,
1602 	.release	= single_release,
1603 };
1604 
1605 /*
1606  * ---------------------------------------------------------------------
1607  * rs_init() and friends
1608  *
1609  * rs_init() is called at boot-time to initialize the serial driver.
1610  * ---------------------------------------------------------------------
1611  */
1612 
1613 /*
1614  * This routine prints out the appropriate serial driver version
1615  * number, and identifies which options were configured into this
1616  * driver.
1617  */
1618 static void show_serial_version(void)
1619 {
1620  	printk(KERN_INFO "%s version %s\n", serial_name, serial_version);
1621 }
1622 
1623 
1624 static const struct tty_operations serial_ops = {
1625 	.open = rs_open,
1626 	.close = rs_close,
1627 	.write = rs_write,
1628 	.put_char = rs_put_char,
1629 	.flush_chars = rs_flush_chars,
1630 	.write_room = rs_write_room,
1631 	.chars_in_buffer = rs_chars_in_buffer,
1632 	.flush_buffer = rs_flush_buffer,
1633 	.ioctl = rs_ioctl,
1634 	.throttle = rs_throttle,
1635 	.unthrottle = rs_unthrottle,
1636 	.set_termios = rs_set_termios,
1637 	.stop = rs_stop,
1638 	.start = rs_start,
1639 	.hangup = rs_hangup,
1640 	.break_ctl = rs_break,
1641 	.send_xchar = rs_send_xchar,
1642 	.wait_until_sent = rs_wait_until_sent,
1643 	.tiocmget = rs_tiocmget,
1644 	.tiocmset = rs_tiocmset,
1645 	.get_icount = rs_get_icount,
1646 	.proc_fops = &rs_proc_fops,
1647 };
1648 
1649 static int amiga_carrier_raised(struct tty_port *port)
1650 {
1651 	return !(ciab.pra & SER_DCD);
1652 }
1653 
1654 static void amiga_dtr_rts(struct tty_port *port, int raise)
1655 {
1656 	struct serial_state *info = container_of(port, struct serial_state,
1657 			tport);
1658 	unsigned long flags;
1659 
1660 	if (raise)
1661 		info->MCR |= SER_DTR|SER_RTS;
1662 	else
1663 		info->MCR &= ~(SER_DTR|SER_RTS);
1664 
1665 	local_irq_save(flags);
1666 	rtsdtr_ctrl(info->MCR);
1667 	local_irq_restore(flags);
1668 }
1669 
1670 static const struct tty_port_operations amiga_port_ops = {
1671 	.carrier_raised = amiga_carrier_raised,
1672 	.dtr_rts = amiga_dtr_rts,
1673 };
1674 
1675 /*
1676  * The serial driver boot-time initialization code!
1677  */
1678 static int __init amiga_serial_probe(struct platform_device *pdev)
1679 {
1680 	unsigned long flags;
1681 	struct serial_state * state;
1682 	int error;
1683 
1684 	serial_driver = alloc_tty_driver(NR_PORTS);
1685 	if (!serial_driver)
1686 		return -ENOMEM;
1687 
1688 	show_serial_version();
1689 
1690 	/* Initialize the tty_driver structure */
1691 
1692 	serial_driver->driver_name = "amiserial";
1693 	serial_driver->name = "ttyS";
1694 	serial_driver->major = TTY_MAJOR;
1695 	serial_driver->minor_start = 64;
1696 	serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
1697 	serial_driver->subtype = SERIAL_TYPE_NORMAL;
1698 	serial_driver->init_termios = tty_std_termios;
1699 	serial_driver->init_termios.c_cflag =
1700 		B9600 | CS8 | CREAD | HUPCL | CLOCAL;
1701 	serial_driver->flags = TTY_DRIVER_REAL_RAW;
1702 	tty_set_operations(serial_driver, &serial_ops);
1703 
1704 	state = rs_table;
1705 	state->port = (int)&custom.serdatr; /* Just to give it a value */
1706 	state->custom_divisor = 0;
1707 	state->icount.cts = state->icount.dsr =
1708 	  state->icount.rng = state->icount.dcd = 0;
1709 	state->icount.rx = state->icount.tx = 0;
1710 	state->icount.frame = state->icount.parity = 0;
1711 	state->icount.overrun = state->icount.brk = 0;
1712 	tty_port_init(&state->tport);
1713 	state->tport.ops = &amiga_port_ops;
1714 	tty_port_link_device(&state->tport, serial_driver, 0);
1715 
1716 	error = tty_register_driver(serial_driver);
1717 	if (error)
1718 		goto fail_put_tty_driver;
1719 
1720 	printk(KERN_INFO "ttyS0 is the amiga builtin serial port\n");
1721 
1722 	/* Hardware set up */
1723 
1724 	state->baud_base = amiga_colorclock;
1725 	state->xmit_fifo_size = 1;
1726 
1727 	/* set ISRs, and then disable the rx interrupts */
1728 	error = request_irq(IRQ_AMIGA_TBE, ser_tx_int, 0, "serial TX", state);
1729 	if (error)
1730 		goto fail_unregister;
1731 
1732 	error = request_irq(IRQ_AMIGA_RBF, ser_rx_int, 0,
1733 			    "serial RX", state);
1734 	if (error)
1735 		goto fail_free_irq;
1736 
1737 	local_irq_save(flags);
1738 
1739 	/* turn off Rx and Tx interrupts */
1740 	custom.intena = IF_RBF | IF_TBE;
1741 	mb();
1742 
1743 	/* clear any pending interrupt */
1744 	custom.intreq = IF_RBF | IF_TBE;
1745 	mb();
1746 
1747 	local_irq_restore(flags);
1748 
1749 	/*
1750 	 * set the appropriate directions for the modem control flags,
1751 	 * and clear RTS and DTR
1752 	 */
1753 	ciab.ddra |= (SER_DTR | SER_RTS);   /* outputs */
1754 	ciab.ddra &= ~(SER_DCD | SER_CTS | SER_DSR);  /* inputs */
1755 
1756 	platform_set_drvdata(pdev, state);
1757 
1758 	return 0;
1759 
1760 fail_free_irq:
1761 	free_irq(IRQ_AMIGA_TBE, state);
1762 fail_unregister:
1763 	tty_unregister_driver(serial_driver);
1764 fail_put_tty_driver:
1765 	tty_port_destroy(&state->tport);
1766 	put_tty_driver(serial_driver);
1767 	return error;
1768 }
1769 
1770 static int __exit amiga_serial_remove(struct platform_device *pdev)
1771 {
1772 	int error;
1773 	struct serial_state *state = platform_get_drvdata(pdev);
1774 
1775 	/* printk("Unloading %s: version %s\n", serial_name, serial_version); */
1776 	error = tty_unregister_driver(serial_driver);
1777 	if (error)
1778 		printk("SERIAL: failed to unregister serial driver (%d)\n",
1779 		       error);
1780 	put_tty_driver(serial_driver);
1781 	tty_port_destroy(&state->tport);
1782 
1783 	free_irq(IRQ_AMIGA_TBE, state);
1784 	free_irq(IRQ_AMIGA_RBF, state);
1785 
1786 	return error;
1787 }
1788 
1789 static struct platform_driver amiga_serial_driver = {
1790 	.remove = __exit_p(amiga_serial_remove),
1791 	.driver   = {
1792 		.name	= "amiga-serial",
1793 	},
1794 };
1795 
1796 module_platform_driver_probe(amiga_serial_driver, amiga_serial_probe);
1797 
1798 
1799 #if defined(CONFIG_SERIAL_CONSOLE) && !defined(MODULE)
1800 
1801 /*
1802  * ------------------------------------------------------------
1803  * Serial console driver
1804  * ------------------------------------------------------------
1805  */
1806 
1807 static void amiga_serial_putc(char c)
1808 {
1809 	custom.serdat = (unsigned char)c | 0x100;
1810 	while (!(custom.serdatr & 0x2000))
1811 		barrier();
1812 }
1813 
1814 /*
1815  *	Print a string to the serial port trying not to disturb
1816  *	any possible real use of the port...
1817  *
1818  *	The console must be locked when we get here.
1819  */
1820 static void serial_console_write(struct console *co, const char *s,
1821 				unsigned count)
1822 {
1823 	unsigned short intena = custom.intenar;
1824 
1825 	custom.intena = IF_TBE;
1826 
1827 	while (count--) {
1828 		if (*s == '\n')
1829 			amiga_serial_putc('\r');
1830 		amiga_serial_putc(*s++);
1831 	}
1832 
1833 	custom.intena = IF_SETCLR | (intena & IF_TBE);
1834 }
1835 
1836 static struct tty_driver *serial_console_device(struct console *c, int *index)
1837 {
1838 	*index = 0;
1839 	return serial_driver;
1840 }
1841 
1842 static struct console sercons = {
1843 	.name =		"ttyS",
1844 	.write =	serial_console_write,
1845 	.device =	serial_console_device,
1846 	.flags =	CON_PRINTBUFFER,
1847 	.index =	-1,
1848 };
1849 
1850 /*
1851  *	Register console.
1852  */
1853 static int __init amiserial_console_init(void)
1854 {
1855 	if (!MACH_IS_AMIGA)
1856 		return -ENODEV;
1857 
1858 	register_console(&sercons);
1859 	return 0;
1860 }
1861 console_initcall(amiserial_console_init);
1862 
1863 #endif /* CONFIG_SERIAL_CONSOLE && !MODULE */
1864 
1865 MODULE_LICENSE("GPL");
1866 MODULE_ALIAS("platform:amiga-serial");
1867