xref: /openbmc/linux/drivers/tty/amiserial.c (revision f9834f18)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Serial driver for the amiga builtin port.
4  *
5  * This code was created by taking serial.c version 4.30 from kernel
6  * release 2.3.22, replacing all hardware related stuff with the
7  * corresponding amiga hardware actions, and removing all irrelevant
8  * code. As a consequence, it uses many of the constants and names
9  * associated with the registers and bits of 16550 compatible UARTS -
10  * but only to keep track of status, etc in the state variables. It
11  * was done this was to make it easier to keep the code in line with
12  * (non hardware specific) changes to serial.c.
13  *
14  * The port is registered with the tty driver as minor device 64, and
15  * therefore other ports should should only use 65 upwards.
16  *
17  * Richard Lucock 28/12/99
18  *
19  *  Copyright (C) 1991, 1992  Linus Torvalds
20  *  Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997,
21  * 		1998, 1999  Theodore Ts'o
22  *
23  */
24 
25 #include <linux/delay.h>
26 
27 /* Set of debugging defines */
28 
29 #undef SERIAL_DEBUG_INTR
30 #undef SERIAL_DEBUG_OPEN
31 #undef SERIAL_DEBUG_FLOW
32 #undef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
33 
34 /* Sanity checks */
35 
36 #if defined(MODULE) && defined(SERIAL_DEBUG_MCOUNT)
37 #define DBG_CNT(s) printk("(%s): [%x] refc=%d, serc=%d, ttyc=%d -> %s\n", \
38  tty->name, (info->tport.flags), serial_driver->refcount,info->count,tty->count,s)
39 #else
40 #define DBG_CNT(s)
41 #endif
42 
43 /*
44  * End of serial driver configuration section.
45  */
46 
47 #include <linux/module.h>
48 
49 #include <linux/types.h>
50 #include <linux/serial.h>
51 #include <linux/serial_reg.h>
52 static char *serial_version = "4.30";
53 
54 #include <linux/errno.h>
55 #include <linux/signal.h>
56 #include <linux/sched.h>
57 #include <linux/kernel.h>
58 #include <linux/timer.h>
59 #include <linux/interrupt.h>
60 #include <linux/tty.h>
61 #include <linux/tty_flip.h>
62 #include <linux/circ_buf.h>
63 #include <linux/console.h>
64 #include <linux/major.h>
65 #include <linux/string.h>
66 #include <linux/fcntl.h>
67 #include <linux/ptrace.h>
68 #include <linux/ioport.h>
69 #include <linux/mm.h>
70 #include <linux/seq_file.h>
71 #include <linux/slab.h>
72 #include <linux/init.h>
73 #include <linux/bitops.h>
74 #include <linux/platform_device.h>
75 
76 #include <asm/setup.h>
77 
78 
79 #include <asm/irq.h>
80 
81 #include <asm/amigahw.h>
82 #include <asm/amigaints.h>
83 
84 struct serial_state {
85 	struct tty_port		tport;
86 	struct circ_buf		xmit;
87 	struct async_icount	icount;
88 
89 	unsigned long		port;
90 	int			baud_base;
91 	int			xmit_fifo_size;
92 	int			custom_divisor;
93 	int			read_status_mask;
94 	int			ignore_status_mask;
95 	int			timeout;
96 	int			quot;
97 	int			IER; 	/* Interrupt Enable Register */
98 	int			MCR; 	/* Modem control register */
99 	int			x_char;	/* xon/xoff character */
100 };
101 
102 #define custom amiga_custom
103 static char *serial_name = "Amiga-builtin serial driver";
104 
105 static struct tty_driver *serial_driver;
106 
107 /* number of characters left in xmit buffer before we ask for more */
108 #define WAKEUP_CHARS 256
109 
110 static unsigned char current_ctl_bits;
111 
112 static void change_speed(struct tty_struct *tty, struct serial_state *info,
113 		struct ktermios *old);
114 static void rs_wait_until_sent(struct tty_struct *tty, int timeout);
115 
116 
117 static struct serial_state rs_table[1];
118 
119 #define NR_PORTS ARRAY_SIZE(rs_table)
120 
121 #include <linux/uaccess.h>
122 
123 #define serial_isroot()	(capable(CAP_SYS_ADMIN))
124 
125 /* some serial hardware definitions */
126 #define SDR_OVRUN   (1<<15)
127 #define SDR_RBF     (1<<14)
128 #define SDR_TBE     (1<<13)
129 #define SDR_TSRE    (1<<12)
130 
131 #define SERPER_PARENB    (1<<15)
132 
133 #define AC_SETCLR   (1<<15)
134 #define AC_UARTBRK  (1<<11)
135 
136 #define SER_DTR     (1<<7)
137 #define SER_RTS     (1<<6)
138 #define SER_DCD     (1<<5)
139 #define SER_CTS     (1<<4)
140 #define SER_DSR     (1<<3)
141 
142 static __inline__ void rtsdtr_ctrl(int bits)
143 {
144     ciab.pra = ((bits & (SER_RTS | SER_DTR)) ^ (SER_RTS | SER_DTR)) | (ciab.pra & ~(SER_RTS | SER_DTR));
145 }
146 
147 /*
148  * ------------------------------------------------------------
149  * rs_stop() and rs_start()
150  *
151  * This routines are called before setting or resetting tty->stopped.
152  * They enable or disable transmitter interrupts, as necessary.
153  * ------------------------------------------------------------
154  */
155 static void rs_stop(struct tty_struct *tty)
156 {
157 	struct serial_state *info = tty->driver_data;
158 	unsigned long flags;
159 
160 	local_irq_save(flags);
161 	if (info->IER & UART_IER_THRI) {
162 		info->IER &= ~UART_IER_THRI;
163 		/* disable Tx interrupt and remove any pending interrupts */
164 		custom.intena = IF_TBE;
165 		mb();
166 		custom.intreq = IF_TBE;
167 		mb();
168 	}
169 	local_irq_restore(flags);
170 }
171 
172 static void rs_start(struct tty_struct *tty)
173 {
174 	struct serial_state *info = tty->driver_data;
175 	unsigned long flags;
176 
177 	local_irq_save(flags);
178 	if (info->xmit.head != info->xmit.tail
179 	    && info->xmit.buf
180 	    && !(info->IER & UART_IER_THRI)) {
181 		info->IER |= UART_IER_THRI;
182 		custom.intena = IF_SETCLR | IF_TBE;
183 		mb();
184 		/* set a pending Tx Interrupt, transmitter should restart now */
185 		custom.intreq = IF_SETCLR | IF_TBE;
186 		mb();
187 	}
188 	local_irq_restore(flags);
189 }
190 
191 /*
192  * ----------------------------------------------------------------------
193  *
194  * Here starts the interrupt handling routines.  All of the following
195  * subroutines are declared as inline and are folded into
196  * rs_interrupt().  They were separated out for readability's sake.
197  *
198  * Note: rs_interrupt() is a "fast" interrupt, which means that it
199  * runs with interrupts turned off.  People who may want to modify
200  * rs_interrupt() should try to keep the interrupt handler as fast as
201  * possible.  After you are done making modifications, it is not a bad
202  * idea to do:
203  *
204  * gcc -S -DKERNEL -Wall -Wstrict-prototypes -O6 -fomit-frame-pointer serial.c
205  *
206  * and look at the resulting assemble code in serial.s.
207  *
208  * 				- Ted Ts'o (tytso@mit.edu), 7-Mar-93
209  * -----------------------------------------------------------------------
210  */
211 
212 static void receive_chars(struct serial_state *info)
213 {
214         int status;
215 	int serdatr;
216 	unsigned char ch, flag;
217 	struct	async_icount *icount;
218 	int oe = 0;
219 
220 	icount = &info->icount;
221 
222 	status = UART_LSR_DR; /* We obviously have a character! */
223 	serdatr = custom.serdatr;
224 	mb();
225 	custom.intreq = IF_RBF;
226 	mb();
227 
228 	if((serdatr & 0x1ff) == 0)
229 	    status |= UART_LSR_BI;
230 	if(serdatr & SDR_OVRUN)
231 	    status |= UART_LSR_OE;
232 
233 	ch = serdatr & 0xff;
234 	icount->rx++;
235 
236 #ifdef SERIAL_DEBUG_INTR
237 	printk("DR%02x:%02x...", ch, status);
238 #endif
239 	flag = TTY_NORMAL;
240 
241 	/*
242 	 * We don't handle parity or frame errors - but I have left
243 	 * the code in, since I'm not sure that the errors can't be
244 	 * detected.
245 	 */
246 
247 	if (status & (UART_LSR_BI | UART_LSR_PE |
248 		      UART_LSR_FE | UART_LSR_OE)) {
249 	  /*
250 	   * For statistics only
251 	   */
252 	  if (status & UART_LSR_BI) {
253 	    status &= ~(UART_LSR_FE | UART_LSR_PE);
254 	    icount->brk++;
255 	  } else if (status & UART_LSR_PE)
256 	    icount->parity++;
257 	  else if (status & UART_LSR_FE)
258 	    icount->frame++;
259 	  if (status & UART_LSR_OE)
260 	    icount->overrun++;
261 
262 	  /*
263 	   * Now check to see if character should be
264 	   * ignored, and mask off conditions which
265 	   * should be ignored.
266 	   */
267 	  if (status & info->ignore_status_mask)
268 	    goto out;
269 
270 	  status &= info->read_status_mask;
271 
272 	  if (status & (UART_LSR_BI)) {
273 #ifdef SERIAL_DEBUG_INTR
274 	    printk("handling break....");
275 #endif
276 	    flag = TTY_BREAK;
277 	    if (info->tport.flags & ASYNC_SAK)
278 	      do_SAK(info->tport.tty);
279 	  } else if (status & UART_LSR_PE)
280 	    flag = TTY_PARITY;
281 	  else if (status & UART_LSR_FE)
282 	    flag = TTY_FRAME;
283 	  if (status & UART_LSR_OE) {
284 	    /*
285 	     * Overrun is special, since it's
286 	     * reported immediately, and doesn't
287 	     * affect the current character
288 	     */
289 	     oe = 1;
290 	  }
291 	}
292 	tty_insert_flip_char(&info->tport, ch, flag);
293 	if (oe == 1)
294 		tty_insert_flip_char(&info->tport, 0, TTY_OVERRUN);
295 	tty_flip_buffer_push(&info->tport);
296 out:
297 	return;
298 }
299 
300 static void transmit_chars(struct serial_state *info)
301 {
302 	custom.intreq = IF_TBE;
303 	mb();
304 	if (info->x_char) {
305 	        custom.serdat = info->x_char | 0x100;
306 		mb();
307 		info->icount.tx++;
308 		info->x_char = 0;
309 		return;
310 	}
311 	if (info->xmit.head == info->xmit.tail
312 	    || info->tport.tty->stopped
313 	    || info->tport.tty->hw_stopped) {
314 		info->IER &= ~UART_IER_THRI;
315 	        custom.intena = IF_TBE;
316 		mb();
317 		return;
318 	}
319 
320 	custom.serdat = info->xmit.buf[info->xmit.tail++] | 0x100;
321 	mb();
322 	info->xmit.tail = info->xmit.tail & (SERIAL_XMIT_SIZE-1);
323 	info->icount.tx++;
324 
325 	if (CIRC_CNT(info->xmit.head,
326 		     info->xmit.tail,
327 		     SERIAL_XMIT_SIZE) < WAKEUP_CHARS)
328 		tty_wakeup(info->tport.tty);
329 
330 #ifdef SERIAL_DEBUG_INTR
331 	printk("THRE...");
332 #endif
333 	if (info->xmit.head == info->xmit.tail) {
334 	        custom.intena = IF_TBE;
335 		mb();
336 		info->IER &= ~UART_IER_THRI;
337 	}
338 }
339 
340 static void check_modem_status(struct serial_state *info)
341 {
342 	struct tty_port *port = &info->tport;
343 	unsigned char status = ciab.pra & (SER_DCD | SER_CTS | SER_DSR);
344 	unsigned char dstatus;
345 	struct	async_icount *icount;
346 
347 	/* Determine bits that have changed */
348 	dstatus = status ^ current_ctl_bits;
349 	current_ctl_bits = status;
350 
351 	if (dstatus) {
352 		icount = &info->icount;
353 		/* update input line counters */
354 		if (dstatus & SER_DSR)
355 			icount->dsr++;
356 		if (dstatus & SER_DCD) {
357 			icount->dcd++;
358 		}
359 		if (dstatus & SER_CTS)
360 			icount->cts++;
361 		wake_up_interruptible(&port->delta_msr_wait);
362 	}
363 
364 	if (tty_port_check_carrier(port) && (dstatus & SER_DCD)) {
365 #if (defined(SERIAL_DEBUG_OPEN) || defined(SERIAL_DEBUG_INTR))
366 		printk("ttyS%d CD now %s...", info->line,
367 		       (!(status & SER_DCD)) ? "on" : "off");
368 #endif
369 		if (!(status & SER_DCD))
370 			wake_up_interruptible(&port->open_wait);
371 		else {
372 #ifdef SERIAL_DEBUG_OPEN
373 			printk("doing serial hangup...");
374 #endif
375 			if (port->tty)
376 				tty_hangup(port->tty);
377 		}
378 	}
379 	if (tty_port_cts_enabled(port)) {
380 		if (port->tty->hw_stopped) {
381 			if (!(status & SER_CTS)) {
382 #if (defined(SERIAL_DEBUG_INTR) || defined(SERIAL_DEBUG_FLOW))
383 				printk("CTS tx start...");
384 #endif
385 				port->tty->hw_stopped = 0;
386 				info->IER |= UART_IER_THRI;
387 				custom.intena = IF_SETCLR | IF_TBE;
388 				mb();
389 				/* set a pending Tx Interrupt, transmitter should restart now */
390 				custom.intreq = IF_SETCLR | IF_TBE;
391 				mb();
392 				tty_wakeup(port->tty);
393 				return;
394 			}
395 		} else {
396 			if ((status & SER_CTS)) {
397 #if (defined(SERIAL_DEBUG_INTR) || defined(SERIAL_DEBUG_FLOW))
398 				printk("CTS tx stop...");
399 #endif
400 				port->tty->hw_stopped = 1;
401 				info->IER &= ~UART_IER_THRI;
402 				/* disable Tx interrupt and remove any pending interrupts */
403 				custom.intena = IF_TBE;
404 				mb();
405 				custom.intreq = IF_TBE;
406 				mb();
407 			}
408 		}
409 	}
410 }
411 
412 static irqreturn_t ser_vbl_int( int irq, void *data)
413 {
414         /* vbl is just a periodic interrupt we tie into to update modem status */
415 	struct serial_state *info = data;
416 	/*
417 	 * TBD - is it better to unregister from this interrupt or to
418 	 * ignore it if MSI is clear ?
419 	 */
420 	if(info->IER & UART_IER_MSI)
421 	  check_modem_status(info);
422 	return IRQ_HANDLED;
423 }
424 
425 static irqreturn_t ser_rx_int(int irq, void *dev_id)
426 {
427 	struct serial_state *info = dev_id;
428 
429 #ifdef SERIAL_DEBUG_INTR
430 	printk("ser_rx_int...");
431 #endif
432 
433 	if (!info->tport.tty)
434 		return IRQ_NONE;
435 
436 	receive_chars(info);
437 #ifdef SERIAL_DEBUG_INTR
438 	printk("end.\n");
439 #endif
440 	return IRQ_HANDLED;
441 }
442 
443 static irqreturn_t ser_tx_int(int irq, void *dev_id)
444 {
445 	struct serial_state *info = dev_id;
446 
447 	if (custom.serdatr & SDR_TBE) {
448 #ifdef SERIAL_DEBUG_INTR
449 	  printk("ser_tx_int...");
450 #endif
451 
452 	  if (!info->tport.tty)
453 		return IRQ_NONE;
454 
455 	  transmit_chars(info);
456 #ifdef SERIAL_DEBUG_INTR
457 	  printk("end.\n");
458 #endif
459 	}
460 	return IRQ_HANDLED;
461 }
462 
463 /*
464  * -------------------------------------------------------------------
465  * Here ends the serial interrupt routines.
466  * -------------------------------------------------------------------
467  */
468 
469 /*
470  * ---------------------------------------------------------------
471  * Low level utility subroutines for the serial driver:  routines to
472  * figure out the appropriate timeout for an interrupt chain, routines
473  * to initialize and startup a serial port, and routines to shutdown a
474  * serial port.  Useful stuff like that.
475  * ---------------------------------------------------------------
476  */
477 
478 static int startup(struct tty_struct *tty, struct serial_state *info)
479 {
480 	struct tty_port *port = &info->tport;
481 	unsigned long flags;
482 	int	retval=0;
483 	unsigned long page;
484 
485 	page = get_zeroed_page(GFP_KERNEL);
486 	if (!page)
487 		return -ENOMEM;
488 
489 	local_irq_save(flags);
490 
491 	if (tty_port_initialized(port)) {
492 		free_page(page);
493 		goto errout;
494 	}
495 
496 	if (info->xmit.buf)
497 		free_page(page);
498 	else
499 		info->xmit.buf = (unsigned char *) page;
500 
501 #ifdef SERIAL_DEBUG_OPEN
502 	printk("starting up ttys%d ...", info->line);
503 #endif
504 
505 	/* Clear anything in the input buffer */
506 
507 	custom.intreq = IF_RBF;
508 	mb();
509 
510 	retval = request_irq(IRQ_AMIGA_VERTB, ser_vbl_int, 0, "serial status", info);
511 	if (retval) {
512 	  if (serial_isroot()) {
513 	      set_bit(TTY_IO_ERROR, &tty->flags);
514 	    retval = 0;
515 	  }
516 	  goto errout;
517 	}
518 
519 	/* enable both Rx and Tx interrupts */
520 	custom.intena = IF_SETCLR | IF_RBF | IF_TBE;
521 	mb();
522 	info->IER = UART_IER_MSI;
523 
524 	/* remember current state of the DCD and CTS bits */
525 	current_ctl_bits = ciab.pra & (SER_DCD | SER_CTS | SER_DSR);
526 
527 	info->MCR = 0;
528 	if (C_BAUD(tty))
529 	  info->MCR = SER_DTR | SER_RTS;
530 	rtsdtr_ctrl(info->MCR);
531 
532 	clear_bit(TTY_IO_ERROR, &tty->flags);
533 	info->xmit.head = info->xmit.tail = 0;
534 
535 	/*
536 	 * and set the speed of the serial port
537 	 */
538 	change_speed(tty, info, NULL);
539 
540 	tty_port_set_initialized(port, 1);
541 	local_irq_restore(flags);
542 	return 0;
543 
544 errout:
545 	local_irq_restore(flags);
546 	return retval;
547 }
548 
549 /*
550  * This routine will shutdown a serial port; interrupts are disabled, and
551  * DTR is dropped if the hangup on close termio flag is on.
552  */
553 static void shutdown(struct tty_struct *tty, struct serial_state *info)
554 {
555 	unsigned long	flags;
556 	struct serial_state *state;
557 
558 	if (!tty_port_initialized(&info->tport))
559 		return;
560 
561 	state = info;
562 
563 #ifdef SERIAL_DEBUG_OPEN
564 	printk("Shutting down serial port %d ....\n", info->line);
565 #endif
566 
567 	local_irq_save(flags); /* Disable interrupts */
568 
569 	/*
570 	 * clear delta_msr_wait queue to avoid mem leaks: we may free the irq
571 	 * here so the queue might never be waken up
572 	 */
573 	wake_up_interruptible(&info->tport.delta_msr_wait);
574 
575 	/*
576 	 * Free the IRQ, if necessary
577 	 */
578 	free_irq(IRQ_AMIGA_VERTB, info);
579 
580 	if (info->xmit.buf) {
581 		free_page((unsigned long) info->xmit.buf);
582 		info->xmit.buf = NULL;
583 	}
584 
585 	info->IER = 0;
586 	custom.intena = IF_RBF | IF_TBE;
587 	mb();
588 
589 	/* disable break condition */
590 	custom.adkcon = AC_UARTBRK;
591 	mb();
592 
593 	if (C_HUPCL(tty))
594 		info->MCR &= ~(SER_DTR|SER_RTS);
595 	rtsdtr_ctrl(info->MCR);
596 
597 	set_bit(TTY_IO_ERROR, &tty->flags);
598 
599 	tty_port_set_initialized(&info->tport, 0);
600 	local_irq_restore(flags);
601 }
602 
603 
604 /*
605  * This routine is called to set the UART divisor registers to match
606  * the specified baud rate for a serial port.
607  */
608 static void change_speed(struct tty_struct *tty, struct serial_state *info,
609 			 struct ktermios *old_termios)
610 {
611 	struct tty_port *port = &info->tport;
612 	int	quot = 0, baud_base, baud;
613 	unsigned cflag, cval = 0;
614 	int	bits;
615 	unsigned long	flags;
616 
617 	cflag = tty->termios.c_cflag;
618 
619 	/* Byte size is always 8 bits plus parity bit if requested */
620 
621 	cval = 3; bits = 10;
622 	if (cflag & CSTOPB) {
623 		cval |= 0x04;
624 		bits++;
625 	}
626 	if (cflag & PARENB) {
627 		cval |= UART_LCR_PARITY;
628 		bits++;
629 	}
630 	if (!(cflag & PARODD))
631 		cval |= UART_LCR_EPAR;
632 #ifdef CMSPAR
633 	if (cflag & CMSPAR)
634 		cval |= UART_LCR_SPAR;
635 #endif
636 
637 	/* Determine divisor based on baud rate */
638 	baud = tty_get_baud_rate(tty);
639 	if (!baud)
640 		baud = 9600;	/* B0 transition handled in rs_set_termios */
641 	baud_base = info->baud_base;
642 	if (baud == 38400 && (port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST)
643 		quot = info->custom_divisor;
644 	else {
645 		if (baud == 134)
646 			/* Special case since 134 is really 134.5 */
647 			quot = (2*baud_base / 269);
648 		else if (baud)
649 			quot = baud_base / baud;
650 	}
651 	/* If the quotient is zero refuse the change */
652 	if (!quot && old_termios) {
653 		/* FIXME: Will need updating for new tty in the end */
654 		tty->termios.c_cflag &= ~CBAUD;
655 		tty->termios.c_cflag |= (old_termios->c_cflag & CBAUD);
656 		baud = tty_get_baud_rate(tty);
657 		if (!baud)
658 			baud = 9600;
659 		if (baud == 38400 &&
660 		    (port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST)
661 			quot = info->custom_divisor;
662 		else {
663 			if (baud == 134)
664 				/* Special case since 134 is really 134.5 */
665 				quot = (2*baud_base / 269);
666 			else if (baud)
667 				quot = baud_base / baud;
668 		}
669 	}
670 	/* As a last resort, if the quotient is zero, default to 9600 bps */
671 	if (!quot)
672 		quot = baud_base / 9600;
673 	info->quot = quot;
674 	info->timeout = ((info->xmit_fifo_size*HZ*bits*quot) / baud_base);
675 	info->timeout += HZ/50;		/* Add .02 seconds of slop */
676 
677 	/* CTS flow control flag and modem status interrupts */
678 	info->IER &= ~UART_IER_MSI;
679 	if (port->flags & ASYNC_HARDPPS_CD)
680 		info->IER |= UART_IER_MSI;
681 	tty_port_set_cts_flow(port, cflag & CRTSCTS);
682 	if (cflag & CRTSCTS)
683 		info->IER |= UART_IER_MSI;
684 	tty_port_set_check_carrier(port, ~cflag & CLOCAL);
685 	if (~cflag & CLOCAL)
686 		info->IER |= UART_IER_MSI;
687 	/* TBD:
688 	 * Does clearing IER_MSI imply that we should disable the VBL interrupt ?
689 	 */
690 
691 	/*
692 	 * Set up parity check flag
693 	 */
694 
695 	info->read_status_mask = UART_LSR_OE | UART_LSR_DR;
696 	if (I_INPCK(tty))
697 		info->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
698 	if (I_BRKINT(tty) || I_PARMRK(tty))
699 		info->read_status_mask |= UART_LSR_BI;
700 
701 	/*
702 	 * Characters to ignore
703 	 */
704 	info->ignore_status_mask = 0;
705 	if (I_IGNPAR(tty))
706 		info->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
707 	if (I_IGNBRK(tty)) {
708 		info->ignore_status_mask |= UART_LSR_BI;
709 		/*
710 		 * If we're ignore parity and break indicators, ignore
711 		 * overruns too.  (For real raw support).
712 		 */
713 		if (I_IGNPAR(tty))
714 			info->ignore_status_mask |= UART_LSR_OE;
715 	}
716 	/*
717 	 * !!! ignore all characters if CREAD is not set
718 	 */
719 	if ((cflag & CREAD) == 0)
720 		info->ignore_status_mask |= UART_LSR_DR;
721 	local_irq_save(flags);
722 
723 	{
724 	  short serper;
725 
726 	/* Set up the baud rate */
727 	  serper = quot - 1;
728 
729 	/* Enable or disable parity bit */
730 
731 	if(cval & UART_LCR_PARITY)
732 	  serper |= (SERPER_PARENB);
733 
734 	custom.serper = serper;
735 	mb();
736 	}
737 
738 	local_irq_restore(flags);
739 }
740 
741 static int rs_put_char(struct tty_struct *tty, unsigned char ch)
742 {
743 	struct serial_state *info;
744 	unsigned long flags;
745 
746 	info = tty->driver_data;
747 
748 	if (!info->xmit.buf)
749 		return 0;
750 
751 	local_irq_save(flags);
752 	if (CIRC_SPACE(info->xmit.head,
753 		       info->xmit.tail,
754 		       SERIAL_XMIT_SIZE) == 0) {
755 		local_irq_restore(flags);
756 		return 0;
757 	}
758 
759 	info->xmit.buf[info->xmit.head++] = ch;
760 	info->xmit.head &= SERIAL_XMIT_SIZE-1;
761 	local_irq_restore(flags);
762 	return 1;
763 }
764 
765 static void rs_flush_chars(struct tty_struct *tty)
766 {
767 	struct serial_state *info = tty->driver_data;
768 	unsigned long flags;
769 
770 	if (info->xmit.head == info->xmit.tail
771 	    || tty->stopped
772 	    || tty->hw_stopped
773 	    || !info->xmit.buf)
774 		return;
775 
776 	local_irq_save(flags);
777 	info->IER |= UART_IER_THRI;
778 	custom.intena = IF_SETCLR | IF_TBE;
779 	mb();
780 	/* set a pending Tx Interrupt, transmitter should restart now */
781 	custom.intreq = IF_SETCLR | IF_TBE;
782 	mb();
783 	local_irq_restore(flags);
784 }
785 
786 static int rs_write(struct tty_struct * tty, const unsigned char *buf, int count)
787 {
788 	int	c, ret = 0;
789 	struct serial_state *info = tty->driver_data;
790 	unsigned long flags;
791 
792 	if (!info->xmit.buf)
793 		return 0;
794 
795 	local_irq_save(flags);
796 	while (1) {
797 		c = CIRC_SPACE_TO_END(info->xmit.head,
798 				      info->xmit.tail,
799 				      SERIAL_XMIT_SIZE);
800 		if (count < c)
801 			c = count;
802 		if (c <= 0) {
803 			break;
804 		}
805 		memcpy(info->xmit.buf + info->xmit.head, buf, c);
806 		info->xmit.head = ((info->xmit.head + c) &
807 				   (SERIAL_XMIT_SIZE-1));
808 		buf += c;
809 		count -= c;
810 		ret += c;
811 	}
812 	local_irq_restore(flags);
813 
814 	if (info->xmit.head != info->xmit.tail
815 	    && !tty->stopped
816 	    && !tty->hw_stopped
817 	    && !(info->IER & UART_IER_THRI)) {
818 		info->IER |= UART_IER_THRI;
819 		local_irq_disable();
820 		custom.intena = IF_SETCLR | IF_TBE;
821 		mb();
822 		/* set a pending Tx Interrupt, transmitter should restart now */
823 		custom.intreq = IF_SETCLR | IF_TBE;
824 		mb();
825 		local_irq_restore(flags);
826 	}
827 	return ret;
828 }
829 
830 static int rs_write_room(struct tty_struct *tty)
831 {
832 	struct serial_state *info = tty->driver_data;
833 
834 	return CIRC_SPACE(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
835 }
836 
837 static int rs_chars_in_buffer(struct tty_struct *tty)
838 {
839 	struct serial_state *info = tty->driver_data;
840 
841 	return CIRC_CNT(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
842 }
843 
844 static void rs_flush_buffer(struct tty_struct *tty)
845 {
846 	struct serial_state *info = tty->driver_data;
847 	unsigned long flags;
848 
849 	local_irq_save(flags);
850 	info->xmit.head = info->xmit.tail = 0;
851 	local_irq_restore(flags);
852 	tty_wakeup(tty);
853 }
854 
855 /*
856  * This function is used to send a high-priority XON/XOFF character to
857  * the device
858  */
859 static void rs_send_xchar(struct tty_struct *tty, char ch)
860 {
861 	struct serial_state *info = tty->driver_data;
862         unsigned long flags;
863 
864 	info->x_char = ch;
865 	if (ch) {
866 		/* Make sure transmit interrupts are on */
867 
868 	        /* Check this ! */
869 	        local_irq_save(flags);
870 		if(!(custom.intenar & IF_TBE)) {
871 		    custom.intena = IF_SETCLR | IF_TBE;
872 		    mb();
873 		    /* set a pending Tx Interrupt, transmitter should restart now */
874 		    custom.intreq = IF_SETCLR | IF_TBE;
875 		    mb();
876 		}
877 		local_irq_restore(flags);
878 
879 		info->IER |= UART_IER_THRI;
880 	}
881 }
882 
883 /*
884  * ------------------------------------------------------------
885  * rs_throttle()
886  *
887  * This routine is called by the upper-layer tty layer to signal that
888  * incoming characters should be throttled.
889  * ------------------------------------------------------------
890  */
891 static void rs_throttle(struct tty_struct * tty)
892 {
893 	struct serial_state *info = tty->driver_data;
894 	unsigned long flags;
895 #ifdef SERIAL_DEBUG_THROTTLE
896 	printk("throttle %s ....\n", tty_name(tty));
897 #endif
898 
899 	if (I_IXOFF(tty))
900 		rs_send_xchar(tty, STOP_CHAR(tty));
901 
902 	if (C_CRTSCTS(tty))
903 		info->MCR &= ~SER_RTS;
904 
905 	local_irq_save(flags);
906 	rtsdtr_ctrl(info->MCR);
907 	local_irq_restore(flags);
908 }
909 
910 static void rs_unthrottle(struct tty_struct * tty)
911 {
912 	struct serial_state *info = tty->driver_data;
913 	unsigned long flags;
914 #ifdef SERIAL_DEBUG_THROTTLE
915 	printk("unthrottle %s ....\n", tty_name(tty));
916 #endif
917 
918 	if (I_IXOFF(tty)) {
919 		if (info->x_char)
920 			info->x_char = 0;
921 		else
922 			rs_send_xchar(tty, START_CHAR(tty));
923 	}
924 	if (C_CRTSCTS(tty))
925 		info->MCR |= SER_RTS;
926 	local_irq_save(flags);
927 	rtsdtr_ctrl(info->MCR);
928 	local_irq_restore(flags);
929 }
930 
931 /*
932  * ------------------------------------------------------------
933  * rs_ioctl() and friends
934  * ------------------------------------------------------------
935  */
936 
937 static int get_serial_info(struct tty_struct *tty, struct serial_struct *ss)
938 {
939 	struct serial_state *state = tty->driver_data;
940 
941 	tty_lock(tty);
942 	ss->line = tty->index;
943 	ss->port = state->port;
944 	ss->flags = state->tport.flags;
945 	ss->xmit_fifo_size = state->xmit_fifo_size;
946 	ss->baud_base = state->baud_base;
947 	ss->close_delay = state->tport.close_delay;
948 	ss->closing_wait = state->tport.closing_wait;
949 	ss->custom_divisor = state->custom_divisor;
950 	tty_unlock(tty);
951 	return 0;
952 }
953 
954 static int set_serial_info(struct tty_struct *tty, struct serial_struct *ss)
955 {
956 	struct serial_state *state = tty->driver_data;
957 	struct tty_port *port = &state->tport;
958 	bool change_spd;
959 	int 			retval = 0;
960 
961 	tty_lock(tty);
962 	change_spd = ((ss->flags ^ port->flags) & ASYNC_SPD_MASK) ||
963 		ss->custom_divisor != state->custom_divisor;
964 	if (ss->irq || ss->port != state->port ||
965 			ss->xmit_fifo_size != state->xmit_fifo_size) {
966 		tty_unlock(tty);
967 		return -EINVAL;
968 	}
969 
970 	if (!serial_isroot()) {
971 		if ((ss->baud_base != state->baud_base) ||
972 		    (ss->close_delay != port->close_delay) ||
973 		    (ss->xmit_fifo_size != state->xmit_fifo_size) ||
974 		    ((ss->flags & ~ASYNC_USR_MASK) !=
975 		     (port->flags & ~ASYNC_USR_MASK))) {
976 			tty_unlock(tty);
977 			return -EPERM;
978 		}
979 		port->flags = ((port->flags & ~ASYNC_USR_MASK) |
980 			       (ss->flags & ASYNC_USR_MASK));
981 		state->custom_divisor = ss->custom_divisor;
982 		goto check_and_exit;
983 	}
984 
985 	if (ss->baud_base < 9600) {
986 		tty_unlock(tty);
987 		return -EINVAL;
988 	}
989 
990 	/*
991 	 * OK, past this point, all the error checking has been done.
992 	 * At this point, we start making changes.....
993 	 */
994 
995 	state->baud_base = ss->baud_base;
996 	port->flags = ((port->flags & ~ASYNC_FLAGS) |
997 			(ss->flags & ASYNC_FLAGS));
998 	state->custom_divisor = ss->custom_divisor;
999 	port->close_delay = ss->close_delay * HZ/100;
1000 	port->closing_wait = ss->closing_wait * HZ/100;
1001 	port->low_latency = (port->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
1002 
1003 check_and_exit:
1004 	if (tty_port_initialized(port)) {
1005 		if (change_spd) {
1006 			/* warn about deprecation unless clearing */
1007 			if (ss->flags & ASYNC_SPD_MASK)
1008 				dev_warn_ratelimited(tty->dev, "use of SPD flags is deprecated\n");
1009 			change_speed(tty, state, NULL);
1010 		}
1011 	} else
1012 		retval = startup(tty, state);
1013 	tty_unlock(tty);
1014 	return retval;
1015 }
1016 
1017 /*
1018  * get_lsr_info - get line status register info
1019  *
1020  * Purpose: Let user call ioctl() to get info when the UART physically
1021  * 	    is emptied.  On bus types like RS485, the transmitter must
1022  * 	    release the bus after transmitting. This must be done when
1023  * 	    the transmit shift register is empty, not be done when the
1024  * 	    transmit holding register is empty.  This functionality
1025  * 	    allows an RS485 driver to be written in user space.
1026  */
1027 static int get_lsr_info(struct serial_state *info, unsigned int __user *value)
1028 {
1029 	unsigned char status;
1030 	unsigned int result;
1031 	unsigned long flags;
1032 
1033 	local_irq_save(flags);
1034 	status = custom.serdatr;
1035 	mb();
1036 	local_irq_restore(flags);
1037 	result = ((status & SDR_TSRE) ? TIOCSER_TEMT : 0);
1038 	if (copy_to_user(value, &result, sizeof(int)))
1039 		return -EFAULT;
1040 	return 0;
1041 }
1042 
1043 
1044 static int rs_tiocmget(struct tty_struct *tty)
1045 {
1046 	struct serial_state *info = tty->driver_data;
1047 	unsigned char control, status;
1048 	unsigned long flags;
1049 
1050 	if (tty_io_error(tty))
1051 		return -EIO;
1052 
1053 	control = info->MCR;
1054 	local_irq_save(flags);
1055 	status = ciab.pra;
1056 	local_irq_restore(flags);
1057 	return    ((control & SER_RTS) ? TIOCM_RTS : 0)
1058 		| ((control & SER_DTR) ? TIOCM_DTR : 0)
1059 		| (!(status  & SER_DCD) ? TIOCM_CAR : 0)
1060 		| (!(status  & SER_DSR) ? TIOCM_DSR : 0)
1061 		| (!(status  & SER_CTS) ? TIOCM_CTS : 0);
1062 }
1063 
1064 static int rs_tiocmset(struct tty_struct *tty, unsigned int set,
1065 						unsigned int clear)
1066 {
1067 	struct serial_state *info = tty->driver_data;
1068 	unsigned long flags;
1069 
1070 	if (tty_io_error(tty))
1071 		return -EIO;
1072 
1073 	local_irq_save(flags);
1074 	if (set & TIOCM_RTS)
1075 		info->MCR |= SER_RTS;
1076 	if (set & TIOCM_DTR)
1077 		info->MCR |= SER_DTR;
1078 	if (clear & TIOCM_RTS)
1079 		info->MCR &= ~SER_RTS;
1080 	if (clear & TIOCM_DTR)
1081 		info->MCR &= ~SER_DTR;
1082 	rtsdtr_ctrl(info->MCR);
1083 	local_irq_restore(flags);
1084 	return 0;
1085 }
1086 
1087 /*
1088  * rs_break() --- routine which turns the break handling on or off
1089  */
1090 static int rs_break(struct tty_struct *tty, int break_state)
1091 {
1092 	unsigned long flags;
1093 
1094 	local_irq_save(flags);
1095 	if (break_state == -1)
1096 	  custom.adkcon = AC_SETCLR | AC_UARTBRK;
1097 	else
1098 	  custom.adkcon = AC_UARTBRK;
1099 	mb();
1100 	local_irq_restore(flags);
1101 	return 0;
1102 }
1103 
1104 /*
1105  * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1106  * Return: write counters to the user passed counter struct
1107  * NB: both 1->0 and 0->1 transitions are counted except for
1108  *     RI where only 0->1 is counted.
1109  */
1110 static int rs_get_icount(struct tty_struct *tty,
1111 				struct serial_icounter_struct *icount)
1112 {
1113 	struct serial_state *info = tty->driver_data;
1114 	struct async_icount cnow;
1115 	unsigned long flags;
1116 
1117 	local_irq_save(flags);
1118 	cnow = info->icount;
1119 	local_irq_restore(flags);
1120 	icount->cts = cnow.cts;
1121 	icount->dsr = cnow.dsr;
1122 	icount->rng = cnow.rng;
1123 	icount->dcd = cnow.dcd;
1124 	icount->rx = cnow.rx;
1125 	icount->tx = cnow.tx;
1126 	icount->frame = cnow.frame;
1127 	icount->overrun = cnow.overrun;
1128 	icount->parity = cnow.parity;
1129 	icount->brk = cnow.brk;
1130 	icount->buf_overrun = cnow.buf_overrun;
1131 
1132 	return 0;
1133 }
1134 
1135 static int rs_ioctl(struct tty_struct *tty,
1136 		    unsigned int cmd, unsigned long arg)
1137 {
1138 	struct serial_state *info = tty->driver_data;
1139 	struct async_icount cprev, cnow;	/* kernel counter temps */
1140 	void __user *argp = (void __user *)arg;
1141 	unsigned long flags;
1142 	DEFINE_WAIT(wait);
1143 	int ret;
1144 
1145 	if ((cmd != TIOCSERCONFIG) &&
1146 	    (cmd != TIOCMIWAIT) && (cmd != TIOCGICOUNT)) {
1147 		if (tty_io_error(tty))
1148 		    return -EIO;
1149 	}
1150 
1151 	switch (cmd) {
1152 		case TIOCSERCONFIG:
1153 			return 0;
1154 
1155 		case TIOCSERGETLSR: /* Get line status register */
1156 			return get_lsr_info(info, argp);
1157 
1158 		/*
1159 		 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1160 		 * - mask passed in arg for lines of interest
1161  		 *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1162 		 * Caller should use TIOCGICOUNT to see which one it was
1163 		 */
1164 		case TIOCMIWAIT:
1165 			local_irq_save(flags);
1166 			/* note the counters on entry */
1167 			cprev = info->icount;
1168 			local_irq_restore(flags);
1169 			while (1) {
1170 				prepare_to_wait(&info->tport.delta_msr_wait,
1171 						&wait, TASK_INTERRUPTIBLE);
1172 				local_irq_save(flags);
1173 				cnow = info->icount; /* atomic copy */
1174 				local_irq_restore(flags);
1175 				if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
1176 				    cnow.dcd == cprev.dcd && cnow.cts == cprev.cts) {
1177 					ret = -EIO; /* no change => error */
1178 					break;
1179 				}
1180 				if ( ((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1181 				     ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1182 				     ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
1183 				     ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts)) ) {
1184 					ret = 0;
1185 					break;
1186 				}
1187 				schedule();
1188 				/* see if a signal did it */
1189 				if (signal_pending(current)) {
1190 					ret = -ERESTARTSYS;
1191 					break;
1192 				}
1193 				cprev = cnow;
1194 			}
1195 			finish_wait(&info->tport.delta_msr_wait, &wait);
1196 			return ret;
1197 
1198 		default:
1199 			return -ENOIOCTLCMD;
1200 		}
1201 	return 0;
1202 }
1203 
1204 static void rs_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
1205 {
1206 	struct serial_state *info = tty->driver_data;
1207 	unsigned long flags;
1208 	unsigned int cflag = tty->termios.c_cflag;
1209 
1210 	change_speed(tty, info, old_termios);
1211 
1212 	/* Handle transition to B0 status */
1213 	if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD)) {
1214 		info->MCR &= ~(SER_DTR|SER_RTS);
1215 		local_irq_save(flags);
1216 		rtsdtr_ctrl(info->MCR);
1217 		local_irq_restore(flags);
1218 	}
1219 
1220 	/* Handle transition away from B0 status */
1221 	if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1222 		info->MCR |= SER_DTR;
1223 		if (!C_CRTSCTS(tty) || !tty_throttled(tty))
1224 			info->MCR |= SER_RTS;
1225 		local_irq_save(flags);
1226 		rtsdtr_ctrl(info->MCR);
1227 		local_irq_restore(flags);
1228 	}
1229 
1230 	/* Handle turning off CRTSCTS */
1231 	if ((old_termios->c_cflag & CRTSCTS) && !C_CRTSCTS(tty)) {
1232 		tty->hw_stopped = 0;
1233 		rs_start(tty);
1234 	}
1235 
1236 #if 0
1237 	/*
1238 	 * No need to wake up processes in open wait, since they
1239 	 * sample the CLOCAL flag once, and don't recheck it.
1240 	 * XXX  It's not clear whether the current behavior is correct
1241 	 * or not.  Hence, this may change.....
1242 	 */
1243 	if (!(old_termios->c_cflag & CLOCAL) && C_CLOCAL(tty))
1244 		wake_up_interruptible(&info->open_wait);
1245 #endif
1246 }
1247 
1248 /*
1249  * ------------------------------------------------------------
1250  * rs_close()
1251  *
1252  * This routine is called when the serial port gets closed.  First, we
1253  * wait for the last remaining data to be sent.  Then, we unlink its
1254  * async structure from the interrupt chain if necessary, and we free
1255  * that IRQ if nothing is left in the chain.
1256  * ------------------------------------------------------------
1257  */
1258 static void rs_close(struct tty_struct *tty, struct file * filp)
1259 {
1260 	struct serial_state *state = tty->driver_data;
1261 	struct tty_port *port = &state->tport;
1262 
1263 	if (tty_port_close_start(port, tty, filp) == 0)
1264 		return;
1265 
1266 	/*
1267 	 * At this point we stop accepting input.  To do this, we
1268 	 * disable the receive line status interrupts, and tell the
1269 	 * interrupt driver to stop checking the data ready bit in the
1270 	 * line status register.
1271 	 */
1272 	state->read_status_mask &= ~UART_LSR_DR;
1273 	if (tty_port_initialized(port)) {
1274 	        /* disable receive interrupts */
1275 	        custom.intena = IF_RBF;
1276 		mb();
1277 		/* clear any pending receive interrupt */
1278 		custom.intreq = IF_RBF;
1279 		mb();
1280 
1281 		/*
1282 		 * Before we drop DTR, make sure the UART transmitter
1283 		 * has completely drained; this is especially
1284 		 * important if there is a transmit FIFO!
1285 		 */
1286 		rs_wait_until_sent(tty, state->timeout);
1287 	}
1288 	shutdown(tty, state);
1289 	rs_flush_buffer(tty);
1290 
1291 	tty_ldisc_flush(tty);
1292 	port->tty = NULL;
1293 
1294 	tty_port_close_end(port, tty);
1295 }
1296 
1297 /*
1298  * rs_wait_until_sent() --- wait until the transmitter is empty
1299  */
1300 static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
1301 {
1302 	struct serial_state *info = tty->driver_data;
1303 	unsigned long orig_jiffies, char_time;
1304 	int lsr;
1305 
1306 	if (info->xmit_fifo_size == 0)
1307 		return; /* Just in case.... */
1308 
1309 	orig_jiffies = jiffies;
1310 
1311 	/*
1312 	 * Set the check interval to be 1/5 of the estimated time to
1313 	 * send a single character, and make it at least 1.  The check
1314 	 * interval should also be less than the timeout.
1315 	 *
1316 	 * Note: we have to use pretty tight timings here to satisfy
1317 	 * the NIST-PCTS.
1318 	 */
1319 	char_time = (info->timeout - HZ/50) / info->xmit_fifo_size;
1320 	char_time = char_time / 5;
1321 	if (char_time == 0)
1322 		char_time = 1;
1323 	if (timeout)
1324 	  char_time = min_t(unsigned long, char_time, timeout);
1325 	/*
1326 	 * If the transmitter hasn't cleared in twice the approximate
1327 	 * amount of time to send the entire FIFO, it probably won't
1328 	 * ever clear.  This assumes the UART isn't doing flow
1329 	 * control, which is currently the case.  Hence, if it ever
1330 	 * takes longer than info->timeout, this is probably due to a
1331 	 * UART bug of some kind.  So, we clamp the timeout parameter at
1332 	 * 2*info->timeout.
1333 	 */
1334 	if (!timeout || timeout > 2*info->timeout)
1335 		timeout = 2*info->timeout;
1336 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
1337 	printk("In rs_wait_until_sent(%d) check=%lu...", timeout, char_time);
1338 	printk("jiff=%lu...", jiffies);
1339 #endif
1340 	while(!((lsr = custom.serdatr) & SDR_TSRE)) {
1341 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
1342 		printk("serdatr = %d (jiff=%lu)...", lsr, jiffies);
1343 #endif
1344 		msleep_interruptible(jiffies_to_msecs(char_time));
1345 		if (signal_pending(current))
1346 			break;
1347 		if (timeout && time_after(jiffies, orig_jiffies + timeout))
1348 			break;
1349 	}
1350 	__set_current_state(TASK_RUNNING);
1351 
1352 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
1353 	printk("lsr = %d (jiff=%lu)...done\n", lsr, jiffies);
1354 #endif
1355 }
1356 
1357 /*
1358  * rs_hangup() --- called by tty_hangup() when a hangup is signaled.
1359  */
1360 static void rs_hangup(struct tty_struct *tty)
1361 {
1362 	struct serial_state *info = tty->driver_data;
1363 
1364 	rs_flush_buffer(tty);
1365 	shutdown(tty, info);
1366 	info->tport.count = 0;
1367 	tty_port_set_active(&info->tport, 0);
1368 	info->tport.tty = NULL;
1369 	wake_up_interruptible(&info->tport.open_wait);
1370 }
1371 
1372 /*
1373  * This routine is called whenever a serial port is opened.  It
1374  * enables interrupts for a serial port, linking in its async structure into
1375  * the IRQ chain.   It also performs the serial-specific
1376  * initialization for the tty structure.
1377  */
1378 static int rs_open(struct tty_struct *tty, struct file * filp)
1379 {
1380 	struct serial_state *info = rs_table + tty->index;
1381 	struct tty_port *port = &info->tport;
1382 	int retval;
1383 
1384 	port->count++;
1385 	port->tty = tty;
1386 	tty->driver_data = info;
1387 	tty->port = port;
1388 
1389 	port->low_latency = (port->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
1390 
1391 	retval = startup(tty, info);
1392 	if (retval) {
1393 		return retval;
1394 	}
1395 
1396 	return tty_port_block_til_ready(port, tty, filp);
1397 }
1398 
1399 /*
1400  * /proc fs routines....
1401  */
1402 
1403 static inline void line_info(struct seq_file *m, int line,
1404 		struct serial_state *state)
1405 {
1406 	char	stat_buf[30], control, status;
1407 	unsigned long flags;
1408 
1409 	seq_printf(m, "%d: uart:amiga_builtin", line);
1410 
1411 	local_irq_save(flags);
1412 	status = ciab.pra;
1413 	control = tty_port_initialized(&state->tport) ? state->MCR : status;
1414 	local_irq_restore(flags);
1415 
1416 	stat_buf[0] = 0;
1417 	stat_buf[1] = 0;
1418 	if(!(control & SER_RTS))
1419 		strcat(stat_buf, "|RTS");
1420 	if(!(status & SER_CTS))
1421 		strcat(stat_buf, "|CTS");
1422 	if(!(control & SER_DTR))
1423 		strcat(stat_buf, "|DTR");
1424 	if(!(status & SER_DSR))
1425 		strcat(stat_buf, "|DSR");
1426 	if(!(status & SER_DCD))
1427 		strcat(stat_buf, "|CD");
1428 
1429 	if (state->quot)
1430 		seq_printf(m, " baud:%d", state->baud_base / state->quot);
1431 
1432 	seq_printf(m, " tx:%d rx:%d", state->icount.tx, state->icount.rx);
1433 
1434 	if (state->icount.frame)
1435 		seq_printf(m, " fe:%d", state->icount.frame);
1436 
1437 	if (state->icount.parity)
1438 		seq_printf(m, " pe:%d", state->icount.parity);
1439 
1440 	if (state->icount.brk)
1441 		seq_printf(m, " brk:%d", state->icount.brk);
1442 
1443 	if (state->icount.overrun)
1444 		seq_printf(m, " oe:%d", state->icount.overrun);
1445 
1446 	/*
1447 	 * Last thing is the RS-232 status lines
1448 	 */
1449 	seq_printf(m, " %s\n", stat_buf+1);
1450 }
1451 
1452 static int rs_proc_show(struct seq_file *m, void *v)
1453 {
1454 	seq_printf(m, "serinfo:1.0 driver:%s\n", serial_version);
1455 	line_info(m, 0, &rs_table[0]);
1456 	return 0;
1457 }
1458 
1459 /*
1460  * ---------------------------------------------------------------------
1461  * rs_init() and friends
1462  *
1463  * rs_init() is called at boot-time to initialize the serial driver.
1464  * ---------------------------------------------------------------------
1465  */
1466 
1467 /*
1468  * This routine prints out the appropriate serial driver version
1469  * number, and identifies which options were configured into this
1470  * driver.
1471  */
1472 static void show_serial_version(void)
1473 {
1474  	printk(KERN_INFO "%s version %s\n", serial_name, serial_version);
1475 }
1476 
1477 
1478 static const struct tty_operations serial_ops = {
1479 	.open = rs_open,
1480 	.close = rs_close,
1481 	.write = rs_write,
1482 	.put_char = rs_put_char,
1483 	.flush_chars = rs_flush_chars,
1484 	.write_room = rs_write_room,
1485 	.chars_in_buffer = rs_chars_in_buffer,
1486 	.flush_buffer = rs_flush_buffer,
1487 	.ioctl = rs_ioctl,
1488 	.throttle = rs_throttle,
1489 	.unthrottle = rs_unthrottle,
1490 	.set_termios = rs_set_termios,
1491 	.stop = rs_stop,
1492 	.start = rs_start,
1493 	.hangup = rs_hangup,
1494 	.break_ctl = rs_break,
1495 	.send_xchar = rs_send_xchar,
1496 	.wait_until_sent = rs_wait_until_sent,
1497 	.tiocmget = rs_tiocmget,
1498 	.tiocmset = rs_tiocmset,
1499 	.get_icount = rs_get_icount,
1500 	.set_serial = set_serial_info,
1501 	.get_serial = get_serial_info,
1502 	.proc_show = rs_proc_show,
1503 };
1504 
1505 static int amiga_carrier_raised(struct tty_port *port)
1506 {
1507 	return !(ciab.pra & SER_DCD);
1508 }
1509 
1510 static void amiga_dtr_rts(struct tty_port *port, int raise)
1511 {
1512 	struct serial_state *info = container_of(port, struct serial_state,
1513 			tport);
1514 	unsigned long flags;
1515 
1516 	if (raise)
1517 		info->MCR |= SER_DTR|SER_RTS;
1518 	else
1519 		info->MCR &= ~(SER_DTR|SER_RTS);
1520 
1521 	local_irq_save(flags);
1522 	rtsdtr_ctrl(info->MCR);
1523 	local_irq_restore(flags);
1524 }
1525 
1526 static const struct tty_port_operations amiga_port_ops = {
1527 	.carrier_raised = amiga_carrier_raised,
1528 	.dtr_rts = amiga_dtr_rts,
1529 };
1530 
1531 /*
1532  * The serial driver boot-time initialization code!
1533  */
1534 static int __init amiga_serial_probe(struct platform_device *pdev)
1535 {
1536 	unsigned long flags;
1537 	struct serial_state * state;
1538 	int error;
1539 
1540 	serial_driver = alloc_tty_driver(NR_PORTS);
1541 	if (!serial_driver)
1542 		return -ENOMEM;
1543 
1544 	show_serial_version();
1545 
1546 	/* Initialize the tty_driver structure */
1547 
1548 	serial_driver->driver_name = "amiserial";
1549 	serial_driver->name = "ttyS";
1550 	serial_driver->major = TTY_MAJOR;
1551 	serial_driver->minor_start = 64;
1552 	serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
1553 	serial_driver->subtype = SERIAL_TYPE_NORMAL;
1554 	serial_driver->init_termios = tty_std_termios;
1555 	serial_driver->init_termios.c_cflag =
1556 		B9600 | CS8 | CREAD | HUPCL | CLOCAL;
1557 	serial_driver->flags = TTY_DRIVER_REAL_RAW;
1558 	tty_set_operations(serial_driver, &serial_ops);
1559 
1560 	state = rs_table;
1561 	state->port = (int)&custom.serdatr; /* Just to give it a value */
1562 	state->custom_divisor = 0;
1563 	state->icount.cts = state->icount.dsr =
1564 	  state->icount.rng = state->icount.dcd = 0;
1565 	state->icount.rx = state->icount.tx = 0;
1566 	state->icount.frame = state->icount.parity = 0;
1567 	state->icount.overrun = state->icount.brk = 0;
1568 	tty_port_init(&state->tport);
1569 	state->tport.ops = &amiga_port_ops;
1570 	tty_port_link_device(&state->tport, serial_driver, 0);
1571 
1572 	error = tty_register_driver(serial_driver);
1573 	if (error)
1574 		goto fail_put_tty_driver;
1575 
1576 	printk(KERN_INFO "ttyS0 is the amiga builtin serial port\n");
1577 
1578 	/* Hardware set up */
1579 
1580 	state->baud_base = amiga_colorclock;
1581 	state->xmit_fifo_size = 1;
1582 
1583 	/* set ISRs, and then disable the rx interrupts */
1584 	error = request_irq(IRQ_AMIGA_TBE, ser_tx_int, 0, "serial TX", state);
1585 	if (error)
1586 		goto fail_unregister;
1587 
1588 	error = request_irq(IRQ_AMIGA_RBF, ser_rx_int, 0,
1589 			    "serial RX", state);
1590 	if (error)
1591 		goto fail_free_irq;
1592 
1593 	local_irq_save(flags);
1594 
1595 	/* turn off Rx and Tx interrupts */
1596 	custom.intena = IF_RBF | IF_TBE;
1597 	mb();
1598 
1599 	/* clear any pending interrupt */
1600 	custom.intreq = IF_RBF | IF_TBE;
1601 	mb();
1602 
1603 	local_irq_restore(flags);
1604 
1605 	/*
1606 	 * set the appropriate directions for the modem control flags,
1607 	 * and clear RTS and DTR
1608 	 */
1609 	ciab.ddra |= (SER_DTR | SER_RTS);   /* outputs */
1610 	ciab.ddra &= ~(SER_DCD | SER_CTS | SER_DSR);  /* inputs */
1611 
1612 	platform_set_drvdata(pdev, state);
1613 
1614 	return 0;
1615 
1616 fail_free_irq:
1617 	free_irq(IRQ_AMIGA_TBE, state);
1618 fail_unregister:
1619 	tty_unregister_driver(serial_driver);
1620 fail_put_tty_driver:
1621 	tty_port_destroy(&state->tport);
1622 	put_tty_driver(serial_driver);
1623 	return error;
1624 }
1625 
1626 static int __exit amiga_serial_remove(struct platform_device *pdev)
1627 {
1628 	int error;
1629 	struct serial_state *state = platform_get_drvdata(pdev);
1630 
1631 	/* printk("Unloading %s: version %s\n", serial_name, serial_version); */
1632 	error = tty_unregister_driver(serial_driver);
1633 	if (error)
1634 		printk("SERIAL: failed to unregister serial driver (%d)\n",
1635 		       error);
1636 	put_tty_driver(serial_driver);
1637 	tty_port_destroy(&state->tport);
1638 
1639 	free_irq(IRQ_AMIGA_TBE, state);
1640 	free_irq(IRQ_AMIGA_RBF, state);
1641 
1642 	return error;
1643 }
1644 
1645 static struct platform_driver amiga_serial_driver = {
1646 	.remove = __exit_p(amiga_serial_remove),
1647 	.driver   = {
1648 		.name	= "amiga-serial",
1649 	},
1650 };
1651 
1652 module_platform_driver_probe(amiga_serial_driver, amiga_serial_probe);
1653 
1654 
1655 #if defined(CONFIG_SERIAL_CONSOLE) && !defined(MODULE)
1656 
1657 /*
1658  * ------------------------------------------------------------
1659  * Serial console driver
1660  * ------------------------------------------------------------
1661  */
1662 
1663 static void amiga_serial_putc(char c)
1664 {
1665 	custom.serdat = (unsigned char)c | 0x100;
1666 	while (!(custom.serdatr & 0x2000))
1667 		barrier();
1668 }
1669 
1670 /*
1671  *	Print a string to the serial port trying not to disturb
1672  *	any possible real use of the port...
1673  *
1674  *	The console must be locked when we get here.
1675  */
1676 static void serial_console_write(struct console *co, const char *s,
1677 				unsigned count)
1678 {
1679 	unsigned short intena = custom.intenar;
1680 
1681 	custom.intena = IF_TBE;
1682 
1683 	while (count--) {
1684 		if (*s == '\n')
1685 			amiga_serial_putc('\r');
1686 		amiga_serial_putc(*s++);
1687 	}
1688 
1689 	custom.intena = IF_SETCLR | (intena & IF_TBE);
1690 }
1691 
1692 static struct tty_driver *serial_console_device(struct console *c, int *index)
1693 {
1694 	*index = 0;
1695 	return serial_driver;
1696 }
1697 
1698 static struct console sercons = {
1699 	.name =		"ttyS",
1700 	.write =	serial_console_write,
1701 	.device =	serial_console_device,
1702 	.flags =	CON_PRINTBUFFER,
1703 	.index =	-1,
1704 };
1705 
1706 /*
1707  *	Register console.
1708  */
1709 static int __init amiserial_console_init(void)
1710 {
1711 	if (!MACH_IS_AMIGA)
1712 		return -ENODEV;
1713 
1714 	register_console(&sercons);
1715 	return 0;
1716 }
1717 console_initcall(amiserial_console_init);
1718 
1719 #endif /* CONFIG_SERIAL_CONSOLE && !MODULE */
1720 
1721 MODULE_LICENSE("GPL");
1722 MODULE_ALIAS("platform:amiga-serial");
1723