xref: /linux/drivers/tty/amiserial.c (revision f3a8b6645dc2e60d11f20c1c23afd964ff4e55ae)
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 (tty_port_check_carrier(port) && (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 (tty_port_initialized(port)) {
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 	tty_port_set_initialized(port, 1);
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 (!tty_port_initialized(&info->tport))
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 	tty_port_set_initialized(&info->tport, 0);
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 	tty_port_set_cts_flow(port, cflag & CRTSCTS);
731 	if (cflag & CRTSCTS)
732 		info->IER |= UART_IER_MSI;
733 	tty_port_set_check_carrier(port, ~cflag & CLOCAL);
734 	if (~cflag & CLOCAL)
735 		info->IER |= UART_IER_MSI;
736 	/* TBD:
737 	 * Does clearing IER_MSI imply that we should disable the VBL interrupt ?
738 	 */
739 
740 	/*
741 	 * Set up parity check flag
742 	 */
743 
744 	info->read_status_mask = UART_LSR_OE | UART_LSR_DR;
745 	if (I_INPCK(tty))
746 		info->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
747 	if (I_BRKINT(tty) || I_PARMRK(tty))
748 		info->read_status_mask |= UART_LSR_BI;
749 
750 	/*
751 	 * Characters to ignore
752 	 */
753 	info->ignore_status_mask = 0;
754 	if (I_IGNPAR(tty))
755 		info->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
756 	if (I_IGNBRK(tty)) {
757 		info->ignore_status_mask |= UART_LSR_BI;
758 		/*
759 		 * If we're ignore parity and break indicators, ignore
760 		 * overruns too.  (For real raw support).
761 		 */
762 		if (I_IGNPAR(tty))
763 			info->ignore_status_mask |= UART_LSR_OE;
764 	}
765 	/*
766 	 * !!! ignore all characters if CREAD is not set
767 	 */
768 	if ((cflag & CREAD) == 0)
769 		info->ignore_status_mask |= UART_LSR_DR;
770 	local_irq_save(flags);
771 
772 	{
773 	  short serper;
774 
775 	/* Set up the baud rate */
776 	  serper = quot - 1;
777 
778 	/* Enable or disable parity bit */
779 
780 	if(cval & UART_LCR_PARITY)
781 	  serper |= (SERPER_PARENB);
782 
783 	custom.serper = serper;
784 	mb();
785 	}
786 
787 	local_irq_restore(flags);
788 }
789 
790 static int rs_put_char(struct tty_struct *tty, unsigned char ch)
791 {
792 	struct serial_state *info;
793 	unsigned long flags;
794 
795 	info = tty->driver_data;
796 
797 	if (serial_paranoia_check(info, tty->name, "rs_put_char"))
798 		return 0;
799 
800 	if (!info->xmit.buf)
801 		return 0;
802 
803 	local_irq_save(flags);
804 	if (CIRC_SPACE(info->xmit.head,
805 		       info->xmit.tail,
806 		       SERIAL_XMIT_SIZE) == 0) {
807 		local_irq_restore(flags);
808 		return 0;
809 	}
810 
811 	info->xmit.buf[info->xmit.head++] = ch;
812 	info->xmit.head &= SERIAL_XMIT_SIZE-1;
813 	local_irq_restore(flags);
814 	return 1;
815 }
816 
817 static void rs_flush_chars(struct tty_struct *tty)
818 {
819 	struct serial_state *info = tty->driver_data;
820 	unsigned long flags;
821 
822 	if (serial_paranoia_check(info, tty->name, "rs_flush_chars"))
823 		return;
824 
825 	if (info->xmit.head == info->xmit.tail
826 	    || tty->stopped
827 	    || tty->hw_stopped
828 	    || !info->xmit.buf)
829 		return;
830 
831 	local_irq_save(flags);
832 	info->IER |= UART_IER_THRI;
833 	custom.intena = IF_SETCLR | IF_TBE;
834 	mb();
835 	/* set a pending Tx Interrupt, transmitter should restart now */
836 	custom.intreq = IF_SETCLR | IF_TBE;
837 	mb();
838 	local_irq_restore(flags);
839 }
840 
841 static int rs_write(struct tty_struct * tty, const unsigned char *buf, int count)
842 {
843 	int	c, ret = 0;
844 	struct serial_state *info = tty->driver_data;
845 	unsigned long flags;
846 
847 	if (serial_paranoia_check(info, tty->name, "rs_write"))
848 		return 0;
849 
850 	if (!info->xmit.buf)
851 		return 0;
852 
853 	local_irq_save(flags);
854 	while (1) {
855 		c = CIRC_SPACE_TO_END(info->xmit.head,
856 				      info->xmit.tail,
857 				      SERIAL_XMIT_SIZE);
858 		if (count < c)
859 			c = count;
860 		if (c <= 0) {
861 			break;
862 		}
863 		memcpy(info->xmit.buf + info->xmit.head, buf, c);
864 		info->xmit.head = ((info->xmit.head + c) &
865 				   (SERIAL_XMIT_SIZE-1));
866 		buf += c;
867 		count -= c;
868 		ret += c;
869 	}
870 	local_irq_restore(flags);
871 
872 	if (info->xmit.head != info->xmit.tail
873 	    && !tty->stopped
874 	    && !tty->hw_stopped
875 	    && !(info->IER & UART_IER_THRI)) {
876 		info->IER |= UART_IER_THRI;
877 		local_irq_disable();
878 		custom.intena = IF_SETCLR | IF_TBE;
879 		mb();
880 		/* set a pending Tx Interrupt, transmitter should restart now */
881 		custom.intreq = IF_SETCLR | IF_TBE;
882 		mb();
883 		local_irq_restore(flags);
884 	}
885 	return ret;
886 }
887 
888 static int rs_write_room(struct tty_struct *tty)
889 {
890 	struct serial_state *info = tty->driver_data;
891 
892 	if (serial_paranoia_check(info, tty->name, "rs_write_room"))
893 		return 0;
894 	return CIRC_SPACE(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
895 }
896 
897 static int rs_chars_in_buffer(struct tty_struct *tty)
898 {
899 	struct serial_state *info = tty->driver_data;
900 
901 	if (serial_paranoia_check(info, tty->name, "rs_chars_in_buffer"))
902 		return 0;
903 	return CIRC_CNT(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
904 }
905 
906 static void rs_flush_buffer(struct tty_struct *tty)
907 {
908 	struct serial_state *info = tty->driver_data;
909 	unsigned long flags;
910 
911 	if (serial_paranoia_check(info, tty->name, "rs_flush_buffer"))
912 		return;
913 	local_irq_save(flags);
914 	info->xmit.head = info->xmit.tail = 0;
915 	local_irq_restore(flags);
916 	tty_wakeup(tty);
917 }
918 
919 /*
920  * This function is used to send a high-priority XON/XOFF character to
921  * the device
922  */
923 static void rs_send_xchar(struct tty_struct *tty, char ch)
924 {
925 	struct serial_state *info = tty->driver_data;
926         unsigned long flags;
927 
928 	if (serial_paranoia_check(info, tty->name, "rs_send_xchar"))
929 		return;
930 
931 	info->x_char = ch;
932 	if (ch) {
933 		/* Make sure transmit interrupts are on */
934 
935 	        /* Check this ! */
936 	        local_irq_save(flags);
937 		if(!(custom.intenar & IF_TBE)) {
938 		    custom.intena = IF_SETCLR | IF_TBE;
939 		    mb();
940 		    /* set a pending Tx Interrupt, transmitter should restart now */
941 		    custom.intreq = IF_SETCLR | IF_TBE;
942 		    mb();
943 		}
944 		local_irq_restore(flags);
945 
946 		info->IER |= UART_IER_THRI;
947 	}
948 }
949 
950 /*
951  * ------------------------------------------------------------
952  * rs_throttle()
953  *
954  * This routine is called by the upper-layer tty layer to signal that
955  * incoming characters should be throttled.
956  * ------------------------------------------------------------
957  */
958 static void rs_throttle(struct tty_struct * tty)
959 {
960 	struct serial_state *info = tty->driver_data;
961 	unsigned long flags;
962 #ifdef SERIAL_DEBUG_THROTTLE
963 	printk("throttle %s ....\n", tty_name(tty));
964 #endif
965 
966 	if (serial_paranoia_check(info, tty->name, "rs_throttle"))
967 		return;
968 
969 	if (I_IXOFF(tty))
970 		rs_send_xchar(tty, STOP_CHAR(tty));
971 
972 	if (C_CRTSCTS(tty))
973 		info->MCR &= ~SER_RTS;
974 
975 	local_irq_save(flags);
976 	rtsdtr_ctrl(info->MCR);
977 	local_irq_restore(flags);
978 }
979 
980 static void rs_unthrottle(struct tty_struct * tty)
981 {
982 	struct serial_state *info = tty->driver_data;
983 	unsigned long flags;
984 #ifdef SERIAL_DEBUG_THROTTLE
985 	printk("unthrottle %s ....\n", tty_name(tty));
986 #endif
987 
988 	if (serial_paranoia_check(info, tty->name, "rs_unthrottle"))
989 		return;
990 
991 	if (I_IXOFF(tty)) {
992 		if (info->x_char)
993 			info->x_char = 0;
994 		else
995 			rs_send_xchar(tty, START_CHAR(tty));
996 	}
997 	if (C_CRTSCTS(tty))
998 		info->MCR |= SER_RTS;
999 	local_irq_save(flags);
1000 	rtsdtr_ctrl(info->MCR);
1001 	local_irq_restore(flags);
1002 }
1003 
1004 /*
1005  * ------------------------------------------------------------
1006  * rs_ioctl() and friends
1007  * ------------------------------------------------------------
1008  */
1009 
1010 static int get_serial_info(struct tty_struct *tty, struct serial_state *state,
1011 			   struct serial_struct __user * retinfo)
1012 {
1013 	struct serial_struct tmp;
1014 
1015 	if (!retinfo)
1016 		return -EFAULT;
1017 	memset(&tmp, 0, sizeof(tmp));
1018 	tty_lock(tty);
1019 	tmp.line = tty->index;
1020 	tmp.port = state->port;
1021 	tmp.flags = state->tport.flags;
1022 	tmp.xmit_fifo_size = state->xmit_fifo_size;
1023 	tmp.baud_base = state->baud_base;
1024 	tmp.close_delay = state->tport.close_delay;
1025 	tmp.closing_wait = state->tport.closing_wait;
1026 	tmp.custom_divisor = state->custom_divisor;
1027 	tty_unlock(tty);
1028 	if (copy_to_user(retinfo,&tmp,sizeof(*retinfo)))
1029 		return -EFAULT;
1030 	return 0;
1031 }
1032 
1033 static int set_serial_info(struct tty_struct *tty, struct serial_state *state,
1034 			   struct serial_struct __user * new_info)
1035 {
1036 	struct tty_port *port = &state->tport;
1037 	struct serial_struct new_serial;
1038 	bool change_spd;
1039 	int 			retval = 0;
1040 
1041 	if (copy_from_user(&new_serial,new_info,sizeof(new_serial)))
1042 		return -EFAULT;
1043 
1044 	tty_lock(tty);
1045 	change_spd = ((new_serial.flags ^ port->flags) & ASYNC_SPD_MASK) ||
1046 		new_serial.custom_divisor != state->custom_divisor;
1047 	if (new_serial.irq || new_serial.port != state->port ||
1048 			new_serial.xmit_fifo_size != state->xmit_fifo_size) {
1049 		tty_unlock(tty);
1050 		return -EINVAL;
1051 	}
1052 
1053 	if (!serial_isroot()) {
1054 		if ((new_serial.baud_base != state->baud_base) ||
1055 		    (new_serial.close_delay != port->close_delay) ||
1056 		    (new_serial.xmit_fifo_size != state->xmit_fifo_size) ||
1057 		    ((new_serial.flags & ~ASYNC_USR_MASK) !=
1058 		     (port->flags & ~ASYNC_USR_MASK))) {
1059 			tty_unlock(tty);
1060 			return -EPERM;
1061 		}
1062 		port->flags = ((port->flags & ~ASYNC_USR_MASK) |
1063 			       (new_serial.flags & ASYNC_USR_MASK));
1064 		state->custom_divisor = new_serial.custom_divisor;
1065 		goto check_and_exit;
1066 	}
1067 
1068 	if (new_serial.baud_base < 9600) {
1069 		tty_unlock(tty);
1070 		return -EINVAL;
1071 	}
1072 
1073 	/*
1074 	 * OK, past this point, all the error checking has been done.
1075 	 * At this point, we start making changes.....
1076 	 */
1077 
1078 	state->baud_base = new_serial.baud_base;
1079 	port->flags = ((port->flags & ~ASYNC_FLAGS) |
1080 			(new_serial.flags & ASYNC_FLAGS));
1081 	state->custom_divisor = new_serial.custom_divisor;
1082 	port->close_delay = new_serial.close_delay * HZ/100;
1083 	port->closing_wait = new_serial.closing_wait * HZ/100;
1084 	port->low_latency = (port->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
1085 
1086 check_and_exit:
1087 	if (tty_port_initialized(port)) {
1088 		if (change_spd) {
1089 			if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
1090 				tty->alt_speed = 57600;
1091 			if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
1092 				tty->alt_speed = 115200;
1093 			if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
1094 				tty->alt_speed = 230400;
1095 			if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
1096 				tty->alt_speed = 460800;
1097 			change_speed(tty, state, NULL);
1098 		}
1099 	} else
1100 		retval = startup(tty, state);
1101 	tty_unlock(tty);
1102 	return retval;
1103 }
1104 
1105 
1106 /*
1107  * get_lsr_info - get line status register info
1108  *
1109  * Purpose: Let user call ioctl() to get info when the UART physically
1110  * 	    is emptied.  On bus types like RS485, the transmitter must
1111  * 	    release the bus after transmitting. This must be done when
1112  * 	    the transmit shift register is empty, not be done when the
1113  * 	    transmit holding register is empty.  This functionality
1114  * 	    allows an RS485 driver to be written in user space.
1115  */
1116 static int get_lsr_info(struct serial_state *info, unsigned int __user *value)
1117 {
1118 	unsigned char status;
1119 	unsigned int result;
1120 	unsigned long flags;
1121 
1122 	local_irq_save(flags);
1123 	status = custom.serdatr;
1124 	mb();
1125 	local_irq_restore(flags);
1126 	result = ((status & SDR_TSRE) ? TIOCSER_TEMT : 0);
1127 	if (copy_to_user(value, &result, sizeof(int)))
1128 		return -EFAULT;
1129 	return 0;
1130 }
1131 
1132 
1133 static int rs_tiocmget(struct tty_struct *tty)
1134 {
1135 	struct serial_state *info = tty->driver_data;
1136 	unsigned char control, status;
1137 	unsigned long flags;
1138 
1139 	if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
1140 		return -ENODEV;
1141 	if (tty_io_error(tty))
1142 		return -EIO;
1143 
1144 	control = info->MCR;
1145 	local_irq_save(flags);
1146 	status = ciab.pra;
1147 	local_irq_restore(flags);
1148 	return    ((control & SER_RTS) ? TIOCM_RTS : 0)
1149 		| ((control & SER_DTR) ? TIOCM_DTR : 0)
1150 		| (!(status  & SER_DCD) ? TIOCM_CAR : 0)
1151 		| (!(status  & SER_DSR) ? TIOCM_DSR : 0)
1152 		| (!(status  & SER_CTS) ? TIOCM_CTS : 0);
1153 }
1154 
1155 static int rs_tiocmset(struct tty_struct *tty, unsigned int set,
1156 						unsigned int clear)
1157 {
1158 	struct serial_state *info = tty->driver_data;
1159 	unsigned long flags;
1160 
1161 	if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
1162 		return -ENODEV;
1163 	if (tty_io_error(tty))
1164 		return -EIO;
1165 
1166 	local_irq_save(flags);
1167 	if (set & TIOCM_RTS)
1168 		info->MCR |= SER_RTS;
1169 	if (set & TIOCM_DTR)
1170 		info->MCR |= SER_DTR;
1171 	if (clear & TIOCM_RTS)
1172 		info->MCR &= ~SER_RTS;
1173 	if (clear & TIOCM_DTR)
1174 		info->MCR &= ~SER_DTR;
1175 	rtsdtr_ctrl(info->MCR);
1176 	local_irq_restore(flags);
1177 	return 0;
1178 }
1179 
1180 /*
1181  * rs_break() --- routine which turns the break handling on or off
1182  */
1183 static int rs_break(struct tty_struct *tty, int break_state)
1184 {
1185 	struct serial_state *info = tty->driver_data;
1186 	unsigned long flags;
1187 
1188 	if (serial_paranoia_check(info, tty->name, "rs_break"))
1189 		return -EINVAL;
1190 
1191 	local_irq_save(flags);
1192 	if (break_state == -1)
1193 	  custom.adkcon = AC_SETCLR | AC_UARTBRK;
1194 	else
1195 	  custom.adkcon = AC_UARTBRK;
1196 	mb();
1197 	local_irq_restore(flags);
1198 	return 0;
1199 }
1200 
1201 /*
1202  * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1203  * Return: write counters to the user passed counter struct
1204  * NB: both 1->0 and 0->1 transitions are counted except for
1205  *     RI where only 0->1 is counted.
1206  */
1207 static int rs_get_icount(struct tty_struct *tty,
1208 				struct serial_icounter_struct *icount)
1209 {
1210 	struct serial_state *info = tty->driver_data;
1211 	struct async_icount cnow;
1212 	unsigned long flags;
1213 
1214 	local_irq_save(flags);
1215 	cnow = info->icount;
1216 	local_irq_restore(flags);
1217 	icount->cts = cnow.cts;
1218 	icount->dsr = cnow.dsr;
1219 	icount->rng = cnow.rng;
1220 	icount->dcd = cnow.dcd;
1221 	icount->rx = cnow.rx;
1222 	icount->tx = cnow.tx;
1223 	icount->frame = cnow.frame;
1224 	icount->overrun = cnow.overrun;
1225 	icount->parity = cnow.parity;
1226 	icount->brk = cnow.brk;
1227 	icount->buf_overrun = cnow.buf_overrun;
1228 
1229 	return 0;
1230 }
1231 
1232 static int rs_ioctl(struct tty_struct *tty,
1233 		    unsigned int cmd, unsigned long arg)
1234 {
1235 	struct serial_state *info = tty->driver_data;
1236 	struct async_icount cprev, cnow;	/* kernel counter temps */
1237 	void __user *argp = (void __user *)arg;
1238 	unsigned long flags;
1239 	DEFINE_WAIT(wait);
1240 	int ret;
1241 
1242 	if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
1243 		return -ENODEV;
1244 
1245 	if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
1246 	    (cmd != TIOCSERCONFIG) && (cmd != TIOCSERGSTRUCT) &&
1247 	    (cmd != TIOCMIWAIT) && (cmd != TIOCGICOUNT)) {
1248 		if (tty_io_error(tty))
1249 		    return -EIO;
1250 	}
1251 
1252 	switch (cmd) {
1253 		case TIOCGSERIAL:
1254 			return get_serial_info(tty, info, argp);
1255 		case TIOCSSERIAL:
1256 			return set_serial_info(tty, info, argp);
1257 		case TIOCSERCONFIG:
1258 			return 0;
1259 
1260 		case TIOCSERGETLSR: /* Get line status register */
1261 			return get_lsr_info(info, argp);
1262 
1263 		case TIOCSERGSTRUCT:
1264 			if (copy_to_user(argp,
1265 					 info, sizeof(struct serial_state)))
1266 				return -EFAULT;
1267 			return 0;
1268 
1269 		/*
1270 		 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1271 		 * - mask passed in arg for lines of interest
1272  		 *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1273 		 * Caller should use TIOCGICOUNT to see which one it was
1274 		 */
1275 		case TIOCMIWAIT:
1276 			local_irq_save(flags);
1277 			/* note the counters on entry */
1278 			cprev = info->icount;
1279 			local_irq_restore(flags);
1280 			while (1) {
1281 				prepare_to_wait(&info->tport.delta_msr_wait,
1282 						&wait, TASK_INTERRUPTIBLE);
1283 				local_irq_save(flags);
1284 				cnow = info->icount; /* atomic copy */
1285 				local_irq_restore(flags);
1286 				if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
1287 				    cnow.dcd == cprev.dcd && cnow.cts == cprev.cts) {
1288 					ret = -EIO; /* no change => error */
1289 					break;
1290 				}
1291 				if ( ((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1292 				     ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1293 				     ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
1294 				     ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts)) ) {
1295 					ret = 0;
1296 					break;
1297 				}
1298 				schedule();
1299 				/* see if a signal did it */
1300 				if (signal_pending(current)) {
1301 					ret = -ERESTARTSYS;
1302 					break;
1303 				}
1304 				cprev = cnow;
1305 			}
1306 			finish_wait(&info->tport.delta_msr_wait, &wait);
1307 			return ret;
1308 
1309 		case TIOCSERGWILD:
1310 		case TIOCSERSWILD:
1311 			/* "setserial -W" is called in Debian boot */
1312 			printk ("TIOCSER?WILD ioctl obsolete, ignored.\n");
1313 			return 0;
1314 
1315 		default:
1316 			return -ENOIOCTLCMD;
1317 		}
1318 	return 0;
1319 }
1320 
1321 static void rs_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
1322 {
1323 	struct serial_state *info = tty->driver_data;
1324 	unsigned long flags;
1325 	unsigned int cflag = tty->termios.c_cflag;
1326 
1327 	change_speed(tty, info, old_termios);
1328 
1329 	/* Handle transition to B0 status */
1330 	if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD)) {
1331 		info->MCR &= ~(SER_DTR|SER_RTS);
1332 		local_irq_save(flags);
1333 		rtsdtr_ctrl(info->MCR);
1334 		local_irq_restore(flags);
1335 	}
1336 
1337 	/* Handle transition away from B0 status */
1338 	if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1339 		info->MCR |= SER_DTR;
1340 		if (!C_CRTSCTS(tty) || !tty_throttled(tty))
1341 			info->MCR |= SER_RTS;
1342 		local_irq_save(flags);
1343 		rtsdtr_ctrl(info->MCR);
1344 		local_irq_restore(flags);
1345 	}
1346 
1347 	/* Handle turning off CRTSCTS */
1348 	if ((old_termios->c_cflag & CRTSCTS) && !C_CRTSCTS(tty)) {
1349 		tty->hw_stopped = 0;
1350 		rs_start(tty);
1351 	}
1352 
1353 #if 0
1354 	/*
1355 	 * No need to wake up processes in open wait, since they
1356 	 * sample the CLOCAL flag once, and don't recheck it.
1357 	 * XXX  It's not clear whether the current behavior is correct
1358 	 * or not.  Hence, this may change.....
1359 	 */
1360 	if (!(old_termios->c_cflag & CLOCAL) && C_CLOCAL(tty))
1361 		wake_up_interruptible(&info->open_wait);
1362 #endif
1363 }
1364 
1365 /*
1366  * ------------------------------------------------------------
1367  * rs_close()
1368  *
1369  * This routine is called when the serial port gets closed.  First, we
1370  * wait for the last remaining data to be sent.  Then, we unlink its
1371  * async structure from the interrupt chain if necessary, and we free
1372  * that IRQ if nothing is left in the chain.
1373  * ------------------------------------------------------------
1374  */
1375 static void rs_close(struct tty_struct *tty, struct file * filp)
1376 {
1377 	struct serial_state *state = tty->driver_data;
1378 	struct tty_port *port = &state->tport;
1379 
1380 	if (serial_paranoia_check(state, tty->name, "rs_close"))
1381 		return;
1382 
1383 	if (tty_port_close_start(port, tty, filp) == 0)
1384 		return;
1385 
1386 	/*
1387 	 * At this point we stop accepting input.  To do this, we
1388 	 * disable the receive line status interrupts, and tell the
1389 	 * interrupt driver to stop checking the data ready bit in the
1390 	 * line status register.
1391 	 */
1392 	state->read_status_mask &= ~UART_LSR_DR;
1393 	if (tty_port_initialized(port)) {
1394 	        /* disable receive interrupts */
1395 	        custom.intena = IF_RBF;
1396 		mb();
1397 		/* clear any pending receive interrupt */
1398 		custom.intreq = IF_RBF;
1399 		mb();
1400 
1401 		/*
1402 		 * Before we drop DTR, make sure the UART transmitter
1403 		 * has completely drained; this is especially
1404 		 * important if there is a transmit FIFO!
1405 		 */
1406 		rs_wait_until_sent(tty, state->timeout);
1407 	}
1408 	shutdown(tty, state);
1409 	rs_flush_buffer(tty);
1410 
1411 	tty_ldisc_flush(tty);
1412 	port->tty = NULL;
1413 
1414 	tty_port_close_end(port, tty);
1415 }
1416 
1417 /*
1418  * rs_wait_until_sent() --- wait until the transmitter is empty
1419  */
1420 static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
1421 {
1422 	struct serial_state *info = tty->driver_data;
1423 	unsigned long orig_jiffies, char_time;
1424 	int lsr;
1425 
1426 	if (serial_paranoia_check(info, tty->name, "rs_wait_until_sent"))
1427 		return;
1428 
1429 	if (info->xmit_fifo_size == 0)
1430 		return; /* Just in case.... */
1431 
1432 	orig_jiffies = jiffies;
1433 
1434 	/*
1435 	 * Set the check interval to be 1/5 of the estimated time to
1436 	 * send a single character, and make it at least 1.  The check
1437 	 * interval should also be less than the timeout.
1438 	 *
1439 	 * Note: we have to use pretty tight timings here to satisfy
1440 	 * the NIST-PCTS.
1441 	 */
1442 	char_time = (info->timeout - HZ/50) / info->xmit_fifo_size;
1443 	char_time = char_time / 5;
1444 	if (char_time == 0)
1445 		char_time = 1;
1446 	if (timeout)
1447 	  char_time = min_t(unsigned long, char_time, timeout);
1448 	/*
1449 	 * If the transmitter hasn't cleared in twice the approximate
1450 	 * amount of time to send the entire FIFO, it probably won't
1451 	 * ever clear.  This assumes the UART isn't doing flow
1452 	 * control, which is currently the case.  Hence, if it ever
1453 	 * takes longer than info->timeout, this is probably due to a
1454 	 * UART bug of some kind.  So, we clamp the timeout parameter at
1455 	 * 2*info->timeout.
1456 	 */
1457 	if (!timeout || timeout > 2*info->timeout)
1458 		timeout = 2*info->timeout;
1459 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
1460 	printk("In rs_wait_until_sent(%d) check=%lu...", timeout, char_time);
1461 	printk("jiff=%lu...", jiffies);
1462 #endif
1463 	while(!((lsr = custom.serdatr) & SDR_TSRE)) {
1464 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
1465 		printk("serdatr = %d (jiff=%lu)...", lsr, jiffies);
1466 #endif
1467 		msleep_interruptible(jiffies_to_msecs(char_time));
1468 		if (signal_pending(current))
1469 			break;
1470 		if (timeout && time_after(jiffies, orig_jiffies + timeout))
1471 			break;
1472 	}
1473 	__set_current_state(TASK_RUNNING);
1474 
1475 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
1476 	printk("lsr = %d (jiff=%lu)...done\n", lsr, jiffies);
1477 #endif
1478 }
1479 
1480 /*
1481  * rs_hangup() --- called by tty_hangup() when a hangup is signaled.
1482  */
1483 static void rs_hangup(struct tty_struct *tty)
1484 {
1485 	struct serial_state *info = tty->driver_data;
1486 
1487 	if (serial_paranoia_check(info, tty->name, "rs_hangup"))
1488 		return;
1489 
1490 	rs_flush_buffer(tty);
1491 	shutdown(tty, info);
1492 	info->tport.count = 0;
1493 	tty_port_set_active(&info->tport, 0);
1494 	info->tport.tty = NULL;
1495 	wake_up_interruptible(&info->tport.open_wait);
1496 }
1497 
1498 /*
1499  * This routine is called whenever a serial port is opened.  It
1500  * enables interrupts for a serial port, linking in its async structure into
1501  * the IRQ chain.   It also performs the serial-specific
1502  * initialization for the tty structure.
1503  */
1504 static int rs_open(struct tty_struct *tty, struct file * filp)
1505 {
1506 	struct serial_state *info = rs_table + tty->index;
1507 	struct tty_port *port = &info->tport;
1508 	int retval;
1509 
1510 	port->count++;
1511 	port->tty = tty;
1512 	tty->driver_data = info;
1513 	tty->port = port;
1514 	if (serial_paranoia_check(info, tty->name, "rs_open"))
1515 		return -ENODEV;
1516 
1517 	port->low_latency = (port->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
1518 
1519 	retval = startup(tty, info);
1520 	if (retval) {
1521 		return retval;
1522 	}
1523 
1524 	return tty_port_block_til_ready(port, tty, filp);
1525 }
1526 
1527 /*
1528  * /proc fs routines....
1529  */
1530 
1531 static inline void line_info(struct seq_file *m, int line,
1532 		struct serial_state *state)
1533 {
1534 	char	stat_buf[30], control, status;
1535 	unsigned long flags;
1536 
1537 	seq_printf(m, "%d: uart:amiga_builtin", line);
1538 
1539 	local_irq_save(flags);
1540 	status = ciab.pra;
1541 	control = tty_port_initialized(&state->tport) ? state->MCR : status;
1542 	local_irq_restore(flags);
1543 
1544 	stat_buf[0] = 0;
1545 	stat_buf[1] = 0;
1546 	if(!(control & SER_RTS))
1547 		strcat(stat_buf, "|RTS");
1548 	if(!(status & SER_CTS))
1549 		strcat(stat_buf, "|CTS");
1550 	if(!(control & SER_DTR))
1551 		strcat(stat_buf, "|DTR");
1552 	if(!(status & SER_DSR))
1553 		strcat(stat_buf, "|DSR");
1554 	if(!(status & SER_DCD))
1555 		strcat(stat_buf, "|CD");
1556 
1557 	if (state->quot)
1558 		seq_printf(m, " baud:%d", state->baud_base / state->quot);
1559 
1560 	seq_printf(m, " tx:%d rx:%d", state->icount.tx, state->icount.rx);
1561 
1562 	if (state->icount.frame)
1563 		seq_printf(m, " fe:%d", state->icount.frame);
1564 
1565 	if (state->icount.parity)
1566 		seq_printf(m, " pe:%d", state->icount.parity);
1567 
1568 	if (state->icount.brk)
1569 		seq_printf(m, " brk:%d", state->icount.brk);
1570 
1571 	if (state->icount.overrun)
1572 		seq_printf(m, " oe:%d", state->icount.overrun);
1573 
1574 	/*
1575 	 * Last thing is the RS-232 status lines
1576 	 */
1577 	seq_printf(m, " %s\n", stat_buf+1);
1578 }
1579 
1580 static int rs_proc_show(struct seq_file *m, void *v)
1581 {
1582 	seq_printf(m, "serinfo:1.0 driver:%s\n", serial_version);
1583 	line_info(m, 0, &rs_table[0]);
1584 	return 0;
1585 }
1586 
1587 static int rs_proc_open(struct inode *inode, struct file *file)
1588 {
1589 	return single_open(file, rs_proc_show, NULL);
1590 }
1591 
1592 static const struct file_operations rs_proc_fops = {
1593 	.owner		= THIS_MODULE,
1594 	.open		= rs_proc_open,
1595 	.read		= seq_read,
1596 	.llseek		= seq_lseek,
1597 	.release	= single_release,
1598 };
1599 
1600 /*
1601  * ---------------------------------------------------------------------
1602  * rs_init() and friends
1603  *
1604  * rs_init() is called at boot-time to initialize the serial driver.
1605  * ---------------------------------------------------------------------
1606  */
1607 
1608 /*
1609  * This routine prints out the appropriate serial driver version
1610  * number, and identifies which options were configured into this
1611  * driver.
1612  */
1613 static void show_serial_version(void)
1614 {
1615  	printk(KERN_INFO "%s version %s\n", serial_name, serial_version);
1616 }
1617 
1618 
1619 static const struct tty_operations serial_ops = {
1620 	.open = rs_open,
1621 	.close = rs_close,
1622 	.write = rs_write,
1623 	.put_char = rs_put_char,
1624 	.flush_chars = rs_flush_chars,
1625 	.write_room = rs_write_room,
1626 	.chars_in_buffer = rs_chars_in_buffer,
1627 	.flush_buffer = rs_flush_buffer,
1628 	.ioctl = rs_ioctl,
1629 	.throttle = rs_throttle,
1630 	.unthrottle = rs_unthrottle,
1631 	.set_termios = rs_set_termios,
1632 	.stop = rs_stop,
1633 	.start = rs_start,
1634 	.hangup = rs_hangup,
1635 	.break_ctl = rs_break,
1636 	.send_xchar = rs_send_xchar,
1637 	.wait_until_sent = rs_wait_until_sent,
1638 	.tiocmget = rs_tiocmget,
1639 	.tiocmset = rs_tiocmset,
1640 	.get_icount = rs_get_icount,
1641 	.proc_fops = &rs_proc_fops,
1642 };
1643 
1644 static int amiga_carrier_raised(struct tty_port *port)
1645 {
1646 	return !(ciab.pra & SER_DCD);
1647 }
1648 
1649 static void amiga_dtr_rts(struct tty_port *port, int raise)
1650 {
1651 	struct serial_state *info = container_of(port, struct serial_state,
1652 			tport);
1653 	unsigned long flags;
1654 
1655 	if (raise)
1656 		info->MCR |= SER_DTR|SER_RTS;
1657 	else
1658 		info->MCR &= ~(SER_DTR|SER_RTS);
1659 
1660 	local_irq_save(flags);
1661 	rtsdtr_ctrl(info->MCR);
1662 	local_irq_restore(flags);
1663 }
1664 
1665 static const struct tty_port_operations amiga_port_ops = {
1666 	.carrier_raised = amiga_carrier_raised,
1667 	.dtr_rts = amiga_dtr_rts,
1668 };
1669 
1670 /*
1671  * The serial driver boot-time initialization code!
1672  */
1673 static int __init amiga_serial_probe(struct platform_device *pdev)
1674 {
1675 	unsigned long flags;
1676 	struct serial_state * state;
1677 	int error;
1678 
1679 	serial_driver = alloc_tty_driver(NR_PORTS);
1680 	if (!serial_driver)
1681 		return -ENOMEM;
1682 
1683 	show_serial_version();
1684 
1685 	/* Initialize the tty_driver structure */
1686 
1687 	serial_driver->driver_name = "amiserial";
1688 	serial_driver->name = "ttyS";
1689 	serial_driver->major = TTY_MAJOR;
1690 	serial_driver->minor_start = 64;
1691 	serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
1692 	serial_driver->subtype = SERIAL_TYPE_NORMAL;
1693 	serial_driver->init_termios = tty_std_termios;
1694 	serial_driver->init_termios.c_cflag =
1695 		B9600 | CS8 | CREAD | HUPCL | CLOCAL;
1696 	serial_driver->flags = TTY_DRIVER_REAL_RAW;
1697 	tty_set_operations(serial_driver, &serial_ops);
1698 
1699 	state = rs_table;
1700 	state->port = (int)&custom.serdatr; /* Just to give it a value */
1701 	state->custom_divisor = 0;
1702 	state->icount.cts = state->icount.dsr =
1703 	  state->icount.rng = state->icount.dcd = 0;
1704 	state->icount.rx = state->icount.tx = 0;
1705 	state->icount.frame = state->icount.parity = 0;
1706 	state->icount.overrun = state->icount.brk = 0;
1707 	tty_port_init(&state->tport);
1708 	state->tport.ops = &amiga_port_ops;
1709 	tty_port_link_device(&state->tport, serial_driver, 0);
1710 
1711 	error = tty_register_driver(serial_driver);
1712 	if (error)
1713 		goto fail_put_tty_driver;
1714 
1715 	printk(KERN_INFO "ttyS0 is the amiga builtin serial port\n");
1716 
1717 	/* Hardware set up */
1718 
1719 	state->baud_base = amiga_colorclock;
1720 	state->xmit_fifo_size = 1;
1721 
1722 	/* set ISRs, and then disable the rx interrupts */
1723 	error = request_irq(IRQ_AMIGA_TBE, ser_tx_int, 0, "serial TX", state);
1724 	if (error)
1725 		goto fail_unregister;
1726 
1727 	error = request_irq(IRQ_AMIGA_RBF, ser_rx_int, 0,
1728 			    "serial RX", state);
1729 	if (error)
1730 		goto fail_free_irq;
1731 
1732 	local_irq_save(flags);
1733 
1734 	/* turn off Rx and Tx interrupts */
1735 	custom.intena = IF_RBF | IF_TBE;
1736 	mb();
1737 
1738 	/* clear any pending interrupt */
1739 	custom.intreq = IF_RBF | IF_TBE;
1740 	mb();
1741 
1742 	local_irq_restore(flags);
1743 
1744 	/*
1745 	 * set the appropriate directions for the modem control flags,
1746 	 * and clear RTS and DTR
1747 	 */
1748 	ciab.ddra |= (SER_DTR | SER_RTS);   /* outputs */
1749 	ciab.ddra &= ~(SER_DCD | SER_CTS | SER_DSR);  /* inputs */
1750 
1751 	platform_set_drvdata(pdev, state);
1752 
1753 	return 0;
1754 
1755 fail_free_irq:
1756 	free_irq(IRQ_AMIGA_TBE, state);
1757 fail_unregister:
1758 	tty_unregister_driver(serial_driver);
1759 fail_put_tty_driver:
1760 	tty_port_destroy(&state->tport);
1761 	put_tty_driver(serial_driver);
1762 	return error;
1763 }
1764 
1765 static int __exit amiga_serial_remove(struct platform_device *pdev)
1766 {
1767 	int error;
1768 	struct serial_state *state = platform_get_drvdata(pdev);
1769 
1770 	/* printk("Unloading %s: version %s\n", serial_name, serial_version); */
1771 	error = tty_unregister_driver(serial_driver);
1772 	if (error)
1773 		printk("SERIAL: failed to unregister serial driver (%d)\n",
1774 		       error);
1775 	put_tty_driver(serial_driver);
1776 	tty_port_destroy(&state->tport);
1777 
1778 	free_irq(IRQ_AMIGA_TBE, state);
1779 	free_irq(IRQ_AMIGA_RBF, state);
1780 
1781 	return error;
1782 }
1783 
1784 static struct platform_driver amiga_serial_driver = {
1785 	.remove = __exit_p(amiga_serial_remove),
1786 	.driver   = {
1787 		.name	= "amiga-serial",
1788 	},
1789 };
1790 
1791 module_platform_driver_probe(amiga_serial_driver, amiga_serial_probe);
1792 
1793 
1794 #if defined(CONFIG_SERIAL_CONSOLE) && !defined(MODULE)
1795 
1796 /*
1797  * ------------------------------------------------------------
1798  * Serial console driver
1799  * ------------------------------------------------------------
1800  */
1801 
1802 static void amiga_serial_putc(char c)
1803 {
1804 	custom.serdat = (unsigned char)c | 0x100;
1805 	while (!(custom.serdatr & 0x2000))
1806 		barrier();
1807 }
1808 
1809 /*
1810  *	Print a string to the serial port trying not to disturb
1811  *	any possible real use of the port...
1812  *
1813  *	The console must be locked when we get here.
1814  */
1815 static void serial_console_write(struct console *co, const char *s,
1816 				unsigned count)
1817 {
1818 	unsigned short intena = custom.intenar;
1819 
1820 	custom.intena = IF_TBE;
1821 
1822 	while (count--) {
1823 		if (*s == '\n')
1824 			amiga_serial_putc('\r');
1825 		amiga_serial_putc(*s++);
1826 	}
1827 
1828 	custom.intena = IF_SETCLR | (intena & IF_TBE);
1829 }
1830 
1831 static struct tty_driver *serial_console_device(struct console *c, int *index)
1832 {
1833 	*index = 0;
1834 	return serial_driver;
1835 }
1836 
1837 static struct console sercons = {
1838 	.name =		"ttyS",
1839 	.write =	serial_console_write,
1840 	.device =	serial_console_device,
1841 	.flags =	CON_PRINTBUFFER,
1842 	.index =	-1,
1843 };
1844 
1845 /*
1846  *	Register console.
1847  */
1848 static int __init amiserial_console_init(void)
1849 {
1850 	if (!MACH_IS_AMIGA)
1851 		return -ENODEV;
1852 
1853 	register_console(&sercons);
1854 	return 0;
1855 }
1856 console_initcall(amiserial_console_init);
1857 
1858 #endif /* CONFIG_SERIAL_CONSOLE && !MODULE */
1859 
1860 MODULE_LICENSE("GPL");
1861 MODULE_ALIAS("platform:amiga-serial");
1862