aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/serial/jsm/jsm_tty.c
blob: f8262e6ad8d3c3fc9728e621248c2d54f70bf2e5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
/************************************************************************
 * Copyright 2003 Digi International (www.digi.com)
 *
 * Copyright (C) 2004 IBM Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
 * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE.  See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 * Temple Place - Suite 330, Boston,
 * MA  02111-1307, USA.
 *
 * Contact Information:
 * Scott H Kilau <Scott_Kilau@digi.com>
 * Ananda Venkatarman <mansarov@us.ibm.com>
 * Modifications:
 * 01/19/06:	changed jsm_input routine to use the dynamically allocated
 *		tty_buffer changes. Contributors: Scott Kilau and Ananda V.
 ***********************************************************************/
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_reg.h>
#include <linux/delay.h>	/* For udelay */
#include <linux/pci.h>

#include "jsm.h"

static void jsm_carrier(struct jsm_channel *ch);

static inline int jsm_get_mstat(struct jsm_channel *ch)
{
	unsigned char mstat;
	unsigned result;

	jsm_printk(IOCTL, INFO, &ch->ch_bd->pci_dev, "start\n");

	mstat = (ch->ch_mostat | ch->ch_mistat);

	result = 0;

	if (mstat & UART_MCR_DTR)
		result |= TIOCM_DTR;
	if (mstat & UART_MCR_RTS)
		result |= TIOCM_RTS;
	if (mstat & UART_MSR_CTS)
		result |= TIOCM_CTS;
	if (mstat & UART_MSR_DSR)
		result |= TIOCM_DSR;
	if (mstat & UART_MSR_RI)
		result |= TIOCM_RI;
	if (mstat & UART_MSR_DCD)
		result |= TIOCM_CD;

	jsm_printk(IOCTL, INFO, &ch->ch_bd->pci_dev, "finish\n");
	return result;
}

static unsigned int jsm_tty_tx_empty(struct uart_port *port)
{
	return TIOCSER_TEMT;
}

/*
 * Return modem signals to ld.
 */
static unsigned int jsm_tty_get_mctrl(struct uart_port *port)
{
	int result;
	struct jsm_channel *channel = (struct jsm_channel *)port;

	jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "start\n");

	result = jsm_get_mstat(channel);

	if (result < 0)
		return -ENXIO;

	jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "finish\n");

	return result;
}

/*
 * jsm_set_modem_info()
 *
 * Set modem signals, called by ld.
 */
static void jsm_tty_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
	struct jsm_channel *channel = (struct jsm_channel *)port;

	jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "start\n");

	if (mctrl & TIOCM_RTS)
		channel->ch_mostat |= UART_MCR_RTS;
	else
		channel->ch_mostat &= ~UART_MCR_RTS;

	if (mctrl & TIOCM_DTR)
		channel->ch_mostat |= UART_MCR_DTR;
	else
		channel->ch_mostat &= ~UART_MCR_DTR;

	channel->ch_bd->bd_ops->assert_modem_signals(channel);

	jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "finish\n");
	udelay(10);
}

static void jsm_tty_start_tx(struct uart_port *port)
{
	struct jsm_channel *channel = (struct jsm_channel *)port;

	jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "start\n");

	channel->ch_flags &= ~(CH_STOP);
	jsm_tty_write(port);

	jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "finish\n");
}

static void jsm_tty_stop_tx(struct uart_port *port)
{
	struct jsm_channel *channel = (struct jsm_channel *)port;

	jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "start\n");

	channel->ch_flags |= (CH_STOP);

	jsm_printk(IOCTL, INFO, &channel->ch_bd->pci_dev, "finish\n");
}

static void jsm_tty_send_xchar(struct uart_port *port, char ch)
{
	unsigned long lock_flags;
	struct jsm_channel *channel = (struct jsm_channel *)port;
	struct termios *termios;

	spin_lock_irqsave(&port->lock, lock_flags);
	termios = port->info->tty->termios;
	if (ch == termios->c_cc[VSTART])
		channel->ch_bd->bd_ops->send_start_character(channel);

	if (ch == termios->c_cc[VSTOP])
		channel->ch_bd->bd_ops->send_stop_character(channel);
	spin_unlock_irqrestore(&port->lock, lock_flags);
}

static void jsm_tty_stop_rx(struct uart_port *port)
{
	struct jsm_channel *channel = (struct jsm_channel *)port;

	channel->ch_bd->bd_ops->disable_receiver(channel);
}

static void jsm_tty_break(struct uart_port *port, int break_state)
{
	unsigned long lock_flags;
	struct jsm_channel *channel = (struct jsm_channel *)port;

	spin_lock_irqsave(&port->lock, lock_flags);
	if (break_state == -1)
		channel->ch_bd->bd_ops->send_break(channel);
	else
		channel->ch_bd->bd_ops->clear_break(channel, 0);

	spin_unlock_irqrestore(&port->lock, lock_flags);
}

static int jsm_tty_open(struct uart_port *port)
{
	struct jsm_board *brd;
	int rc = 0;
	struct jsm_channel *channel = (struct jsm_channel *)port;
	struct termios *termios;

	/* Get board pointer from our array of majors we have allocated */
	brd = channel->ch_bd;

	/*
	 * Allocate channel buffers for read/write/error.
	 * Set flag, so we don't get trounced on.
	 */
	channel->ch_flags |= (CH_OPENING);

	/* Drop locks, as malloc with GFP_KERNEL can sleep */

	if (!channel->ch_rqueue) {
		channel->ch_rqueue = (u8 *) kmalloc(RQUEUESIZE, GFP_KERNEL);
		if (!channel->ch_rqueue) {
			jsm_printk(INIT, ERR, &channel->ch_bd->pci_dev,
				"unable to allocate read queue buf");
			return -ENOMEM;
		}
		memset(channel->ch_rqueue, 0, RQUEUESIZE);
	}
	if (!channel->ch_equeue) {
		channel->ch_equeue = (u8 *) kmalloc(EQUEUESIZE, GFP_KERNEL);
		if (!channel->ch_equeue) {
			jsm_printk(INIT, ERR, &channel->ch_bd->pci_dev,
				"unable to allocate error queue buf");
			return -ENOMEM;
		}
		memset(channel->ch_equeue, 0, EQUEUESIZE);
	}
	if (!channel->ch_wqueue) {
		channel->ch_wqueue = (u8 *) kmalloc(WQUEUESIZE, GFP_KERNEL);
		if (!channel->ch_wqueue) {
			jsm_printk(INIT, ERR, &channel->ch_bd->pci_dev,
				"unable to allocate write queue buf");
			return -ENOMEM;
		}
		memset(channel->ch_wqueue, 0, WQUEUESIZE);
	}

	channel->ch_flags &= ~(CH_OPENING);
	/*
	 * Initialize if neither terminal is open.
	 */
	jsm_printk(OPEN, INFO, &channel->ch_bd->pci_dev,
		"jsm_open: initializing channel in open...\n");

	/*
	 * Flush input queues.
	 */
	channel->ch_r_head = channel->ch_r_tail = 0;
	channel->ch_e_head = channel->ch_e_tail = 0;
	channel->ch_w_head = channel->ch_w_tail = 0;

	brd->bd_ops->flush_uart_write(channel);
	brd->bd_ops->flush_uart_read(channel);

	channel->ch_flags = 0;
	channel->ch_cached_lsr = 0;
	channel->ch_stops_sent = 0;

	termios = port->info->tty->termios;
	channel->ch_c_cflag	= termios->c_cflag;
	channel->ch_c_iflag	= termios->c_iflag;
	channel->ch_c_oflag	= termios->c_oflag;
	channel->ch_c_lflag	= termios->c_lflag;
	channel->ch_startc	= termios->c_cc[VSTART];
	channel->ch_stopc	= termios->c_cc[VSTOP];

	/* Tell UART to init itself */
	brd->bd_ops->uart_init(channel);

	/*
	 * Run param in case we changed anything
	 */
	brd->bd_ops->param(channel);

	jsm_carrier(channel);

	channel->ch_open_count++;

	jsm_printk(OPEN, INFO, &channel->ch_bd->pci_dev, "finish\n");
	return rc;
}

static void jsm_tty_close(struct uart_port *port)
{
	struct jsm_board *bd;
	struct termios *ts;
	struct jsm_channel *channel = (struct jsm_channel *)port;

	jsm_printk(CLOSE, INFO, &channel->ch_bd->pci_dev, "start\n");

	bd = channel->ch_bd;
	ts = channel->uart_port.info->tty->termios;

	channel->ch_flags &= ~(CH_STOPI);

	channel->ch_open_count--;

	/*
	 * If we have HUPCL set, lower DTR and RTS
	 */
	if (channel->ch_c_cflag & HUPCL) {
		jsm_printk(CLOSE, INFO, &channel->ch_bd->pci_dev,
			"Close. HUPCL set, dropping DTR/RTS\n");

		/* Drop RTS/DTR */
		channel->ch_mostat &= ~(UART_MCR_DTR | UART_MCR_RTS);
		bd->bd_ops->assert_modem_signals(channel);
	}

	channel->ch_old_baud = 0;

	/* Turn off UART interrupts for this port */
	channel->ch_bd->bd_ops->uart_off(channel);

	jsm_printk(CLOSE, INFO, &channel->ch_bd->pci_dev, "finish\n");
}

static void jsm_tty_set_termios(struct uart_port *port,
				 struct termios *termios,
				 struct termios *old_termios)
{
	unsigned long lock_flags;
	struct jsm_channel *channel = (struct jsm_channel *)port;

	spin_lock_irqsave(&port->lock, lock_flags);
	channel->ch_c_cflag	= termios->c_cflag;
	channel->ch_c_iflag	= termios->c_iflag;
	channel->ch_c_oflag	= termios->c_oflag;
	channel->ch_c_lflag	= termios->c_lflag;
	channel->ch_startc	= termios->c_cc[VSTART];
	channel->ch_stopc	= termios->c_cc[VSTOP];

	channel->ch_bd->bd_ops->param(channel);
	jsm_carrier(channel);
	spin_unlock_irqrestore(&port->lock, lock_flags);
}

static const char *jsm_tty_type(struct uart_port *port)
{
	return "jsm";
}

static void jsm_tty_release_port(struct uart_port *port)
{
}

static int jsm_tty_request_port(struct uart_port *port)
{
	return 0;
}

static void jsm_config_port(struct uart_port *port, int flags)
{
	port->type = PORT_JSM;
}

static struct uart_ops jsm_ops = {
	.tx_empty	= jsm_tty_tx_empty,
	.set_mctrl	= jsm_tty_set_mctrl,
	.get_mctrl	= jsm_tty_get_mctrl,
	.stop_tx	= jsm_tty_stop_tx,
	.start_tx	= jsm_tty_start_tx,
	.send_xchar	= jsm_tty_send_xchar,
	.stop_rx	= jsm_tty_stop_rx,
	.break_ctl	= jsm_tty_break,
	.startup	= jsm_tty_open,
	.shutdown	= jsm_tty_close,
	.set_termios	= jsm_tty_set_termios,
	.type		= jsm_tty_type,
	.release_port	= jsm_tty_release_port,
	.request_port	= jsm_tty_request_port,
	.config_port	= jsm_config_port,
};

/*
 * jsm_tty_init()
 *
 * Init the tty subsystem.  Called once per board after board has been
 * downloaded and init'ed.
 */
int jsm_tty_init(struct jsm_board *brd)
{
	int i;
	void __iomem *vaddr;
	struct jsm_channel *ch;

	if (!brd)
		return -ENXIO;

	jsm_printk(INIT, INFO, &brd->pci_dev, "start\n");

	/*
	 * Initialize board structure elements.
	 */

	brd->nasync = brd->maxports;

	/*
	 * Allocate channel memory that might not have been allocated
	 * when the driver was first loaded.
	 */
	for (i = 0; i < brd->nasync; i++) {
		if (!brd->channels[i]) {

			/*
			 * Okay to malloc with GFP_KERNEL, we are not at
			 * interrupt context, and there are no locks held.
			 */
			brd->channels[i] = kmalloc(sizeof(struct jsm_channel), GFP_KERNEL);
			if (!brd->channels[i]) {
				jsm_printk(CORE, ERR, &brd->pci_dev,
					"%s:%d Unable to allocate memory for channel struct\n",
							 __FILE__, __LINE__);
			}
			memset(brd->channels[i], 0, sizeof(struct jsm_channel));
		}
	}

	ch = brd->channels[0];
	vaddr = brd->re_map_membase;

	/* Set up channel variables */
	for (i = 0; i < brd->nasync; i++, ch = brd->channels[i]) {

		if (!brd->channels[i])
			continue;

		spin_lock_init(&ch->ch_lock);

		if (brd->bd_uart_offset == 0x200)
			ch->ch_neo_uart =  vaddr + (brd->bd_uart_offset * i);

		ch->ch_bd = brd;
		ch->ch_portnum = i;

		/* .25 second delay */
		ch->ch_close_delay = 250;

		init_waitqueue_head(&ch->ch_flags_wait);
	}

	jsm_printk(INIT, INFO, &brd->pci_dev, "finish\n");
	return 0;
}

int jsm_uart_port_init(struct jsm_board *brd)
{
	int i;
	struct jsm_channel *ch;

	if (!brd)
		return -ENXIO;

	jsm_printk(INIT, INFO, &brd->pci_dev, "start\n");

	/*
	 * Initialize board structure elements.
	 */

	brd->nasync = brd->maxports;

	/* Set up channel variables */
	for (i = 0; i < brd->nasync; i++, ch = brd->channels[i]) {

		if (!brd->channels[i])
			continue;

		brd->channels[i]->uart_port.irq = brd->irq;
		brd->channels[i]->uart_port.type = PORT_JSM;
		brd->channels[i]->uart_port.iotype = UPIO_MEM;
		brd->channels[i]->uart_port.membase = brd->re_map_membase;
		brd->channels[i]->uart_port.fifosize = 16;
		brd->channels[i]->uart_port.ops = &jsm_ops;
		brd->channels[i]->uart_port.line = brd->channels[i]->ch_portnum + brd->boardnum * 2;
		if (uart_add_one_port (&jsm_uart_driver, &brd->channels[i]->uart_port))
			printk(KERN_INFO "Added device failed\n");
		else
			printk(KERN_INFO "Added device \n");
	}

	jsm_printk(INIT, INFO, &brd->pci_dev, "finish\n");
	return 0;
}

int jsm_remove_uart_port(struct jsm_board *brd)
{
	int i;
	struct jsm_channel *ch;

	if (!brd)
		return -ENXIO;

	jsm_printk(INIT, INFO, &brd->pci_dev, "start\n");

	/*
	 * Initialize board structure elements.
	 */

	brd->nasync = brd->maxports;

	/* Set up channel variables */
	for (i = 0; i < brd->nasync; i++) {

		if (!brd->channels[i])
			continue;

		ch = brd->channels[i];

		uart_remove_one_port(&jsm_uart_driver, &brd->channels[i]->uart_port);
	}

	jsm_printk(INIT, INFO, &brd->pci_dev, "finish\n");
	return 0;
}

void jsm_input(struct jsm_channel *ch)
{
	struct jsm_board *bd;
	struct tty_struct *tp;
	struct tty_ldisc *ld;
	u32 rmask;
	u16 head;
	u16 tail;
	int data_len;
	unsigned long lock_flags;
	int flip_len = 0;
	int len = 0;
	int n = 0;
	int s = 0;
	int i = 0;

	jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start\n");

	if (!ch)
		return;

	tp = ch->uart_port.info->tty;

	bd = ch->ch_bd;
	if(!bd)
		return;

	spin_lock_irqsave(&ch->ch_lock, lock_flags);

	/*
	 *Figure the number of characters in the buffer.
	 *Exit immediately if none.
	 */

	rmask = RQUEUEMASK;

	head = ch->ch_r_head & rmask;
	tail = ch->ch_r_tail & rmask;

	data_len = (head - tail) & rmask;
	if (data_len == 0) {
		spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
		return;
	}

	jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start\n");

	/*
	 *If the device is not open, or CREAD is off, flush
	 *input data and return immediately.
	 */
	if (!tp ||
		!(tp->termios->c_cflag & CREAD) ) {

		jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
			"input. dropping %d bytes on port %d...\n", data_len, ch->ch_portnum);
		ch->ch_r_head = tail;

		/* Force queue flow control to be released, if needed */
		jsm_check_queue_flow_control(ch);

		spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
		return;
	}

	/*
	 * If we are throttled, simply don't read any data.
	 */
	if (ch->ch_flags & CH_STOPI) {
		spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
		jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
			"Port %d throttled, not reading any data. head: %x tail: %x\n",
			ch->ch_portnum, head, tail);
		return;
	}

	jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "start 2\n");

	/*
	 * If the rxbuf is empty and we are not throttled, put as much
	 * as we can directly into the linux TTY buffer.
	 *
	 */
	flip_len = TTY_FLIPBUF_SIZE;

	len = min(data_len, flip_len);
	len = min(len, (N_TTY_BUF_SIZE - 1) - tp->read_cnt);
	ld = tty_ldisc_ref(tp);

	/*
	 * If we were unable to get a reference to the ld,
	 * don't flush our buffer, and act like the ld doesn't
	 * have any space to put the data right now.
	 */
	if (!ld) {
		len = 0;
	} else {
		/*
		 * If ld doesn't have a pointer to a receive_buf function,
		 * flush the data, then act like the ld doesn't have any
		 * space to put the data right now.
		 */
		if (!ld->receive_buf) {
				ch->ch_r_head = ch->ch_r_tail;
				len = 0;
		}
	}

	if (len <= 0) {
		spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
		jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "jsm_input 1\n");
		if (ld)
			tty_ldisc_deref(ld);
		return;
	}

	len = tty_buffer_request_room(tp, len);
	n = len;

	/*
	 * n now contains the most amount of data we can copy,
	 * bounded either by the flip buffer size or the amount
	 * of data the card actually has pending...
	 */
	while (n) {
		s = ((head >= tail) ? head : RQUEUESIZE) - tail;
		s = min(s, n);

		if (s <= 0)
			break;

			/*
			 * If conditions are such that ld needs to see all
			 * UART errors, we will have to walk each character
			 * and error byte and send them to the buffer one at
			 * a time.
			 */

		if (I_PARMRK(tp) || I_BRKINT(tp) || I_INPCK(tp)) {
			for (i = 0; i < s; i++) {
				/*
				 * Give the Linux ld the flags in the
				 * format it likes.
				 */
				if (*(ch->ch_equeue +tail +i) & UART_LSR_BI)
					tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i),  TTY_BREAK);
				else if (*(ch->ch_equeue +tail +i) & UART_LSR_PE)
					tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_PARITY);
				else if (*(ch->ch_equeue +tail +i) & UART_LSR_FE)
					tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_FRAME);
				else
				tty_insert_flip_char(tp, *(ch->ch_rqueue +tail +i), TTY_NORMAL);
			}
		} else {
			tty_insert_flip_string(tp, ch->ch_rqueue + tail, s) ;
		}
		tail += s;
		n -= s;
		/* Flip queue if needed */
		tail &= rmask;
	}

	ch->ch_r_tail = tail & rmask;
	ch->ch_e_tail = tail & rmask;
	jsm_check_queue_flow_control(ch);
	spin_unlock_irqrestore(&ch->ch_lock, lock_flags);

	/* Tell the tty layer its okay to "eat" the data now */
	tty_flip_buffer_push(tp);

	if (ld)
		tty_ldisc_deref(ld);

	jsm_printk(IOCTL, INFO, &ch->ch_bd->pci_dev, "finish\n");
}

static void jsm_carrier(struct jsm_channel *ch)
{
	struct jsm_board *bd;

	int virt_carrier = 0;
	int phys_carrier = 0;

	jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev, "start\n");
	if (!ch)
		return;

	bd = ch->ch_bd;

	if (!bd)
		return;

	if (ch->ch_mistat & UART_MSR_DCD) {
		jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
			"mistat: %x D_CD: %x\n", ch->ch_mistat, ch->ch_mistat & UART_MSR_DCD);
		phys_carrier = 1;
	}

	if (ch->ch_c_cflag & CLOCAL)
		virt_carrier = 1;

	jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
		"DCD: physical: %d virt: %d\n", phys_carrier, virt_carrier);

	/*
	 * Test for a VIRTUAL carrier transition to HIGH.
	 */
	if (((ch->ch_flags & CH_FCAR) == 0) && (virt_carrier == 1)) {

		/*
		 * When carrier rises, wake any threads waiting
		 * for carrier in the open routine.
		 */

		jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
			"carrier: virt DCD rose\n");

		if (waitqueue_active(&(ch->ch_flags_wait)))
			wake_up_interruptible(&ch->ch_flags_wait);
	}

	/*
	 * Test for a PHYSICAL carrier transition to HIGH.
	 */
	if (((ch->ch_flags & CH_CD) == 0) && (phys_carrier == 1)) {

		/*
		 * When carrier rises, wake any threads waiting
		 * for carrier in the open routine.
		 */

		jsm_printk(CARR, INFO, &ch->ch_bd->pci_dev,
			"carrier: physical DCD rose\n");

		if (waitqueue_active(&(ch->ch_flags_wait)))
			wake_up_interruptible(&ch->ch_flags_wait);
	}

	/*
	 *  Test for a PHYSICAL transition to low, so long as we aren't
	 *  currently ignoring physical transitions (which is what "virtual
	 *  carrier" indicates).
	 *
	 *  The transition of the virtual carrier to low really doesn't
	 *  matter... it really only means "ignore carrier state", not
	 *  "make pretend that carrier is there".
	 */
	if ((virt_carrier == 0) && ((ch->ch_flags & CH_CD) != 0)
			&& (phys_carrier == 0)) {
		/*
		 *	When carrier drops:
		 *
		 *	Drop carrier on all open units.
		 *
		 *	Flush queues, waking up any task waiting in the
		 *	line discipline.
		 *
		 *	Send a hangup to the control terminal.
		 *
		 *	Enable all select calls.
		 */
		if (waitqueue_active(&(ch->ch_flags_wait)))
			wake_up_interruptible(&ch->ch_flags_wait);
	}

	/*
	 *  Make sure that our cached values reflect the current reality.
	 */
	if (virt_carrier == 1)
		ch->ch_flags |= CH_FCAR;
	else
		ch->ch_flags &= ~CH_FCAR;

	if (phys_carrier == 1)
		ch->ch_flags |= CH_CD;
	else
		ch->ch_flags &= ~CH_CD;
}


void jsm_check_queue_flow_control(struct jsm_channel *ch)
{
	struct board_ops *bd_ops = ch->ch_bd->bd_ops;
	int qleft = 0;

	/* Store how much space we have left in the queue */
	if ((qleft = ch->ch_r_tail - ch->ch_r_head - 1) < 0)
		qleft += RQUEUEMASK + 1;

	/*
	 * Check to see if we should enforce flow control on our queue because
	 * the ld (or user) isn't reading data out of our queue fast enuf.
	 *
	 * NOTE: This is done based on what the current flow control of the
	 * port is set for.
	 *
	 * 1) HWFLOW (RTS) - Turn off the UART's Receive interrupt.
	 *	This will cause the UART's FIFO to back up, and force
	 *	the RTS signal to be dropped.
	 * 2) SWFLOW (IXOFF) - Keep trying to send a stop character to
	 *	the other side, in hopes it will stop sending data to us.
	 * 3) NONE - Nothing we can do.  We will simply drop any extra data
	 *	that gets sent into us when the queue fills up.
	 */
	if (qleft < 256) {
		/* HWFLOW */
		if (ch->ch_c_cflag & CRTSCTS) {
			if(!(ch->ch_flags & CH_RECEIVER_OFF)) {
				bd_ops->disable_receiver(ch);
				ch->ch_flags |= (CH_RECEIVER_OFF);
				jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
					"Internal queue hit hilevel mark (%d)! Turning off interrupts.\n",
					qleft);
			}
		}
		/* SWFLOW */
		else if (ch->ch_c_iflag & IXOFF) {
			if (ch->ch_stops_sent <= MAX_STOPS_SENT) {
				bd_ops->send_stop_character(ch);
				ch->ch_stops_sent++;
				jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
					"Sending stop char! Times sent: %x\n", ch->ch_stops_sent);
			}
		}
	}

	/*
	 * Check to see if we should unenforce flow control because
	 * ld (or user) finally read enuf data out of our queue.
	 *
	 * NOTE: This is done based on what the current flow control of the
	 * port is set for.
	 *
	 * 1) HWFLOW (RTS) - Turn back on the UART's Receive interrupt.
	 *	This will cause the UART's FIFO to raise RTS back up,
	 *	which will allow the other side to start sending data again.
	 * 2) SWFLOW (IXOFF) - Send a start character to
	 *	the other side, so it will start sending data to us again.
	 * 3) NONE - Do nothing. Since we didn't do anything to turn off the
	 *	other side, we don't need to do anything now.
	 */
	if (qleft > (RQUEUESIZE / 2)) {
		/* HWFLOW */
		if (ch->ch_c_cflag & CRTSCTS) {
			if (ch->ch_flags & CH_RECEIVER_OFF) {
				bd_ops->enable_receiver(ch);
				ch->ch_flags &= ~(CH_RECEIVER_OFF);
				jsm_printk(READ, INFO, &ch->ch_bd->pci_dev,
					"Internal queue hit lowlevel mark (%d)! Turning on interrupts.\n",
					qleft);
			}
		}
		/* SWFLOW */
		else if (ch->ch_c_iflag & IXOFF && ch->ch_stops_sent) {
			ch->ch_stops_sent = 0;
			bd_ops->send_start_character(ch);
			jsm_printk(READ, INFO, &ch->ch_bd->pci_dev, "Sending start char!\n");
		}
	}
}

/*
 * jsm_tty_write()
 *
 * Take data from the user or kernel and send it out to the FEP.
 * In here exists all the Transparent Print magic as well.
 */
int jsm_tty_write(struct uart_port *port)
{
	int bufcount = 0, n = 0;
	int data_count = 0,data_count1 =0;
	u16 head;
	u16 tail;
	u16 tmask;
	u32 remain;
	int temp_tail = port->info->xmit.tail;
	struct jsm_channel *channel = (struct jsm_channel *)port;

	tmask = WQUEUEMASK;
	head = (channel->ch_w_head) & tmask;
	tail = (channel->ch_w_tail) & tmask;

	if ((bufcount = tail - head - 1) < 0)
		bufcount += WQUEUESIZE;

	n = bufcount;

	n = min(n, 56);
	remain = WQUEUESIZE - head;

	data_count = 0;
	if (n >= remain) {
		n -= remain;
		while ((port->info->xmit.head != temp_tail) &&
		(data_count < remain)) {
			channel->ch_wqueue[head++] =
			port->info->xmit.buf[temp_tail];

			temp_tail++;
			temp_tail &= (UART_XMIT_SIZE - 1);
			data_count++;
		}
		if (data_count == remain) head = 0;
	}

	data_count1 = 0;
	if (n > 0) {
		remain = n;
		while ((port->info->xmit.head != temp_tail) &&
			(data_count1 < remain)) {
			channel->ch_wqueue[head++] =
				port->info->xmit.buf[temp_tail];

			temp_tail++;
			temp_tail &= (UART_XMIT_SIZE - 1);
			data_count1++;

		}
	}

	port->info->xmit.tail = temp_tail;

	data_count += data_count1;
	if (data_count) {
		head &= tmask;
		channel->ch_w_head = head;
	}

	if (data_count) {
		channel->ch_bd->bd_ops->copy_data_from_queue_to_uart(channel);
	}

	return data_count;
}