aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/net/wan/pc300_tty.c
blob: 4917a94943bd9c1567bd63317b89043c3a08ccb3 (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
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
/*
 * pc300_tty.c	Cyclades-PC300(tm) TTY Driver.
 *
 * Author:	Regina Kodato <reginak@cyclades.com>
 *
 * Copyright:	(c) 1999-2002 Cyclades Corp.
 *
 *	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 of the License, or (at your option) any later version.
 *   
 *  $Log: pc300_tty.c,v $
 *  Revision 3.7  2002/03/07 14:17:09  henrique
 *  License data fixed
 *
 *  Revision 3.6  2001/12/10 12:29:42  regina
 *  Fix the MLPPP bug
 *
 *  Revision 3.5  2001/10/31 11:20:05  regina
 *  automatic pppd starts
 *
 *  Revision 3.4  2001/08/06 12:01:51  regina
 *  problem in DSR_DE bit
 *
 *  Revision 3.3  2001/07/26 22:58:41  regina
 *  update EDA value
 *
 *  Revision 3.2  2001/07/12 13:11:20  regina
 *  bug fix - DCD-OFF in pc300 tty driver
 *
 *	DMA transmission bug fix
 *  
 *  Revision 3.1  2001/06/22 13:13:02  regina
 *  MLPPP implementation
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/if.h>
#include <linux/skbuff.h>
/* TTY includes */
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>

#include <asm/io.h>
#include <asm/uaccess.h>

#include "pc300.h"

/* defines and macros */
/* TTY Global definitions */
#define	CPC_TTY_NPORTS	8	/* maximum number of the sync tty connections */
#define	CPC_TTY_MAJOR	CYCLADES_MAJOR	
#define CPC_TTY_MINOR_START	240	/* minor of the first PC300 interface */

#define CPC_TTY_MAX_MTU	2000	

/* tty interface state */
#define	CPC_TTY_ST_IDLE	0
#define CPC_TTY_ST_INIT	1	/* configured with MLPPP and up */
#define CPC_TTY_ST_OPEN	2	/* opened by application */

#define	CPC_TTY_LOCK(card,flags)\
	do {\
		spin_lock_irqsave(&card->card_lock, flags);	\
	} while (0)

#define CPC_TTY_UNLOCK(card,flags)	\
	do {\
		spin_unlock_irqrestore(&card->card_lock, flags);	\
	} while (0)

//#define	CPC_TTY_DBG(format,a...)	printk(format,##a)
#define	CPC_TTY_DBG(format,a...)

/* data structures */
typedef struct _st_cpc_rx_buf {
	struct _st_cpc_rx_buf	*next;
	int		size;
	unsigned char	data[1];
} st_cpc_rx_buf;

struct st_cpc_rx_list {
	st_cpc_rx_buf	*first;
	st_cpc_rx_buf	*last;
};

typedef	struct _st_cpc_tty_area {
	int		state;		/* state of the TTY interface */
	int		num_open;	
	unsigned int 	tty_minor;	/* minor this interface */
	volatile struct st_cpc_rx_list buf_rx;	/* ptr. to reception buffer */
	unsigned char*	buf_tx;		/* ptr. to transmission buffer */
	pc300dev_t*	pc300dev;	/* ptr. to info struct in PC300 driver */
	unsigned char	name[20];	/* interf. name + "-tty" */
	struct tty_struct *tty;		
	struct work_struct tty_tx_work; /* tx work - tx interrupt */
	struct work_struct tty_rx_work; /* rx work - rx interrupt */
	} st_cpc_tty_area;

/* TTY data structures */
static struct tty_driver serial_drv;

/* local variables */
static st_cpc_tty_area	cpc_tty_area[CPC_TTY_NPORTS];

static int cpc_tty_cnt = 0;	/* number of intrfaces configured with MLPPP */
static int cpc_tty_unreg_flag = 0;

/* TTY functions prototype */
static int cpc_tty_open(struct tty_struct *tty, struct file *flip);
static void cpc_tty_close(struct tty_struct *tty, struct file *flip);
static int cpc_tty_write(struct tty_struct *tty, const unsigned char *buf, int count);
static int cpc_tty_write_room(struct tty_struct *tty);
static int cpc_tty_chars_in_buffer(struct tty_struct *tty);
static void cpc_tty_flush_buffer(struct tty_struct *tty);
static void cpc_tty_hangup(struct tty_struct *tty);
static void cpc_tty_rx_work(struct work_struct *work);
static void cpc_tty_tx_work(struct work_struct *work);
static int cpc_tty_send_to_card(pc300dev_t *dev,void *buf, int len);
static void cpc_tty_trace(pc300dev_t *dev, char* buf, int len, char rxtx);
static void cpc_tty_signal_off(pc300dev_t *pc300dev, unsigned char);
static void cpc_tty_signal_on(pc300dev_t *pc300dev, unsigned char);

static int pc300_tiocmset(struct tty_struct *, struct file *,
			  unsigned int, unsigned int);
static int pc300_tiocmget(struct tty_struct *, struct file *);

/* functions called by PC300 driver */
void cpc_tty_init(pc300dev_t *dev);
void cpc_tty_unregister_service(pc300dev_t *pc300dev);
void cpc_tty_receive(pc300dev_t *pc300dev);
void cpc_tty_trigger_poll(pc300dev_t *pc300dev);
void cpc_tty_reset_var(void);

/*
 * PC300 TTY clear "signal"
 */
static void cpc_tty_signal_off(pc300dev_t *pc300dev, unsigned char signal)
{
	pc300ch_t *pc300chan = (pc300ch_t *)pc300dev->chan; 
	pc300_t *card = (pc300_t *) pc300chan->card; 
	int ch = pc300chan->channel; 
	unsigned long flags; 

	CPC_TTY_DBG("%s-tty: Clear signal %x\n",
		pc300dev->dev->name, signal);
	CPC_TTY_LOCK(card, flags); 
	cpc_writeb(card->hw.scabase + M_REG(CTL,ch), 
		cpc_readb(card->hw.scabase+M_REG(CTL,ch))& signal);
	CPC_TTY_UNLOCK(card,flags); 
}

/*
 * PC300 TTY set "signal" to ON
 */
static void cpc_tty_signal_on(pc300dev_t *pc300dev, unsigned char signal)
{
	pc300ch_t *pc300chan = (pc300ch_t *)pc300dev->chan; 
	pc300_t *card = (pc300_t *) pc300chan->card; 
	int ch = pc300chan->channel; 
	unsigned long flags; 

	CPC_TTY_DBG("%s-tty: Set signal %x\n",
		pc300dev->dev->name, signal);
	CPC_TTY_LOCK(card, flags); 
	cpc_writeb(card->hw.scabase + M_REG(CTL,ch), 
		cpc_readb(card->hw.scabase+M_REG(CTL,ch))& ~signal);
	CPC_TTY_UNLOCK(card,flags); 
}


static const struct tty_operations pc300_ops = {
	.open = cpc_tty_open,
	.close = cpc_tty_close,
	.write = cpc_tty_write,
	.write_room = cpc_tty_write_room,
	.chars_in_buffer = cpc_tty_chars_in_buffer,
	.tiocmset = pc300_tiocmset,
	.tiocmget = pc300_tiocmget,
	.flush_buffer = cpc_tty_flush_buffer,
	.hangup = cpc_tty_hangup,
};


/*
 * PC300 TTY initialization routine
 *
 * This routine is called by the PC300 driver during board configuration 
 * (ioctl=SIOCSP300CONF). At this point the adapter is completely
 * initialized.
 * o verify kernel version (only 2.4.x)
 * o register TTY driver
 * o init cpc_tty_area struct
 */
void cpc_tty_init(pc300dev_t *pc300dev)
{
	unsigned long port;
	int aux;
	st_cpc_tty_area * cpc_tty;

	/* hdlcX - X=interface number */
	port = pc300dev->dev->name[4] - '0';
	if (port >= CPC_TTY_NPORTS) {
		printk("%s-tty: invalid interface selected (0-%i): %li",
			pc300dev->dev->name,
			CPC_TTY_NPORTS-1,port);
		return;
	}

	if (cpc_tty_cnt == 0) { /* first TTY connection -> register driver */
		CPC_TTY_DBG("%s-tty: driver init, major:%i, minor range:%i=%i\n",
			pc300dev->dev->name,
			CPC_TTY_MAJOR, CPC_TTY_MINOR_START,
			CPC_TTY_MINOR_START+CPC_TTY_NPORTS);
		/* initialize tty driver struct */
		memset(&serial_drv,0,sizeof(struct tty_driver));
		serial_drv.magic = TTY_DRIVER_MAGIC;
		serial_drv.owner = THIS_MODULE;
		serial_drv.driver_name = "pc300_tty";
		serial_drv.name = "ttyCP";
		serial_drv.major = CPC_TTY_MAJOR;
		serial_drv.minor_start = CPC_TTY_MINOR_START;
		serial_drv.num = CPC_TTY_NPORTS;
		serial_drv.type = TTY_DRIVER_TYPE_SERIAL;
		serial_drv.subtype = SERIAL_TYPE_NORMAL;

		serial_drv.init_termios = tty_std_termios;
		serial_drv.init_termios.c_cflag = B9600|CS8|CREAD|HUPCL|CLOCAL;
		serial_drv.flags = TTY_DRIVER_REAL_RAW;

		/* interface routines from the upper tty layer to the tty driver */
		tty_set_operations(&serial_drv, &pc300_ops);

		/* register the TTY driver */
		if (tty_register_driver(&serial_drv)) { 
			printk("%s-tty: Failed to register serial driver! ",
				pc300dev->dev->name);
		   	return;
		} 

		memset((void *)cpc_tty_area, 0,
								sizeof(st_cpc_tty_area) * CPC_TTY_NPORTS);
	}

	cpc_tty = &cpc_tty_area[port];
	
	if (cpc_tty->state != CPC_TTY_ST_IDLE) {
		CPC_TTY_DBG("%s-tty: TTY port %i, already in use.\n",
				pc300dev->dev->name, port);
		return;
	}

	cpc_tty_cnt++;
	cpc_tty->state = CPC_TTY_ST_INIT; 
	cpc_tty->num_open= 0;
	cpc_tty->tty_minor = port + CPC_TTY_MINOR_START;
	cpc_tty->pc300dev = pc300dev; 

	INIT_WORK(&cpc_tty->tty_tx_work, cpc_tty_tx_work);
	INIT_WORK(&cpc_tty->tty_rx_work, cpc_tty_rx_work);
	
	cpc_tty->buf_rx.first = cpc_tty->buf_rx.last = NULL;

	pc300dev->cpc_tty = (void *)cpc_tty; 
	
	aux = strlen(pc300dev->dev->name);
	memcpy(cpc_tty->name, pc300dev->dev->name, aux);
	memcpy(&cpc_tty->name[aux], "-tty", 5);
	
	cpc_open(pc300dev->dev);
	cpc_tty_signal_off(pc300dev, CTL_DTR);

	CPC_TTY_DBG("%s: Initializing TTY Sync Driver, tty major#%d minor#%i\n",
			cpc_tty->name,CPC_TTY_MAJOR,cpc_tty->tty_minor); 
	return; 
} 

/*
 * PC300 TTY OPEN routine
 *
 * This routine is called by the tty driver to open the interface 
 * o verify minor
 * o allocate buffer to Rx and Tx
 */
static int cpc_tty_open(struct tty_struct *tty, struct file *flip)
{
	int port ;
	st_cpc_tty_area *cpc_tty;

	if (!tty) { 
		return -ENODEV;
	} 

	port = tty->index;

	if ((port < 0) || (port >= CPC_TTY_NPORTS)){ 
		CPC_TTY_DBG("pc300_tty: open invalid port %d\n", port);
		return -ENODEV;
	} 

	cpc_tty = &cpc_tty_area[port];
	
	if (cpc_tty->state == CPC_TTY_ST_IDLE){
		CPC_TTY_DBG("%s: open - invalid interface, port=%d\n",
					cpc_tty->name, tty->index);
		return -ENODEV;
	}

	if (cpc_tty->num_open == 0) { /* first open of this tty */
		if (!cpc_tty_area[port].buf_tx){
			cpc_tty_area[port].buf_tx = kmalloc(CPC_TTY_MAX_MTU,GFP_KERNEL);
			if (!cpc_tty_area[port].buf_tx) {
				CPC_TTY_DBG("%s: error in memory allocation\n",cpc_tty->name);
				return -ENOMEM;
			}
		} 

		if (cpc_tty_area[port].buf_rx.first) {
			unsigned char * aux;
			while (cpc_tty_area[port].buf_rx.first) {
				aux = (unsigned char *)cpc_tty_area[port].buf_rx.first;
				cpc_tty_area[port].buf_rx.first = cpc_tty_area[port].buf_rx.first->next;
				kfree(aux);
			}
			cpc_tty_area[port].buf_rx.first = NULL;
			cpc_tty_area[port].buf_rx.last = NULL;
		}

		cpc_tty_area[port].state = CPC_TTY_ST_OPEN;
		cpc_tty_area[port].tty = tty;
		tty->driver_data = &cpc_tty_area[port];

		cpc_tty_signal_on(cpc_tty->pc300dev, CTL_DTR);
	} 

	cpc_tty->num_open++;

	CPC_TTY_DBG("%s: opening TTY driver\n", cpc_tty->name);
	
	/* avisar driver PC300 */ 
	return 0; 
}

/*
 * PC300 TTY CLOSE routine
 *
 * This routine is called by the tty driver to close the interface 
 * o call close channel in PC300 driver (cpc_closech)
 * o free Rx and Tx buffers
 */

static void cpc_tty_close(struct tty_struct *tty, struct file *flip)
{
	st_cpc_tty_area    *cpc_tty;
	unsigned long flags;
	int res;

	if (!tty || !tty->driver_data ) {
		CPC_TTY_DBG("hdlx-tty: no TTY in close \n");
		return;
	}

	cpc_tty = (st_cpc_tty_area *) tty->driver_data;

	if ((cpc_tty->tty != tty)|| (cpc_tty->state != CPC_TTY_ST_OPEN)) {
		CPC_TTY_DBG("%s: TTY is not opened\n",cpc_tty->name);
		return;
	}
   	
	if (!cpc_tty->num_open) {
		CPC_TTY_DBG("%s: TTY is closed\n",cpc_tty->name);
		return;
	}

	if (--cpc_tty->num_open > 0) {
		CPC_TTY_DBG("%s: TTY closed\n",cpc_tty->name);
		return;
	}

	cpc_tty_signal_off(cpc_tty->pc300dev, CTL_DTR);

	CPC_TTY_LOCK(cpc_tty->pc300dev->chan->card, flags);  /* lock irq */ 
	cpc_tty->tty = NULL;
	cpc_tty->state = CPC_TTY_ST_INIT;
	CPC_TTY_UNLOCK(cpc_tty->pc300dev->chan->card, flags); /* unlock irq */ 
	
	if (cpc_tty->buf_rx.first) {
		unsigned char * aux;
		while (cpc_tty->buf_rx.first) {
			aux = (unsigned char *)cpc_tty->buf_rx.first;
			cpc_tty->buf_rx.first = cpc_tty->buf_rx.first->next;
			kfree(aux);
		}
		cpc_tty->buf_rx.first = NULL;
		cpc_tty->buf_rx.last = NULL;
	}
	
	kfree(cpc_tty->buf_tx);
	cpc_tty->buf_tx = NULL;

	CPC_TTY_DBG("%s: TTY closed\n",cpc_tty->name);
	
	if (!serial_drv.refcount && cpc_tty_unreg_flag) {
		cpc_tty_unreg_flag = 0;
		CPC_TTY_DBG("%s: unregister the tty driver\n", cpc_tty->name);
		if ((res=tty_unregister_driver(&serial_drv))) { 
			CPC_TTY_DBG("%s: ERROR ->unregister the tty driver error=%d\n",
							cpc_tty->name,res);
		}
	}
	return; 
} 

/*
 * PC300 TTY WRITE routine
 *
 * This routine is called by the tty driver to write a series of characters
 * to the tty device. The characters may come from user or kernel space.
 * o verify the DCD signal
 * o send characters to board and start the transmission
 */
static int cpc_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
{
	st_cpc_tty_area    *cpc_tty; 
	pc300ch_t *pc300chan; 
	pc300_t *card; 
	int ch; 
	unsigned long flags; 
	struct net_device_stats *stats; 

	if (!tty || !tty->driver_data ) { 
		CPC_TTY_DBG("hdlcX-tty: no TTY in write\n");
		return -ENODEV;
	} 

	cpc_tty = (st_cpc_tty_area *) tty->driver_data; 

	if ((cpc_tty->tty != tty) ||  (cpc_tty->state != CPC_TTY_ST_OPEN)) { 
		CPC_TTY_DBG("%s: TTY is not opened\n", cpc_tty->name);
		return -ENODEV; 
	}

	if (count > CPC_TTY_MAX_MTU) { 
		CPC_TTY_DBG("%s: count is invalid\n",cpc_tty->name);
		return -EINVAL;        /* frame too big */ 
	}

	CPC_TTY_DBG("%s: cpc_tty_write data len=%i\n",cpc_tty->name,count);
	
	pc300chan = (pc300ch_t *)((pc300dev_t*)cpc_tty->pc300dev)->chan; 
	stats = &cpc_tty->pc300dev->dev->stats;
	card = (pc300_t *) pc300chan->card;
	ch = pc300chan->channel; 

	/* verify DCD signal*/ 
	if (cpc_readb(card->hw.scabase + M_REG(ST3,ch)) & ST3_DCD) { 
		/* DCD is OFF */ 
		CPC_TTY_DBG("%s : DCD is OFF\n", cpc_tty->name);
		stats->tx_errors++;
		stats->tx_carrier_errors++;
		CPC_TTY_LOCK(card, flags); 
		cpc_writeb(card->hw.scabase + M_REG(CMD, ch), CMD_TX_BUF_CLR); 
		
		if (card->hw.type == PC300_TE) { 
			cpc_writeb(card->hw.falcbase + card->hw.cpld_reg2, 
				cpc_readb(card->hw.falcbase + card->hw.cpld_reg2) & 
				~(CPLD_REG2_FALC_LED1 << (2 *ch))); 
		}

		CPC_TTY_UNLOCK(card, flags); 

		return -EINVAL; 
	}

	if (cpc_tty_send_to_card(cpc_tty->pc300dev, (void*)buf, count)) { 
	   /* failed to send */
	   CPC_TTY_DBG("%s: trasmition error\n", cpc_tty->name);
	   return 0;
	}
	return count; 
} 

/*
 * PC300 TTY Write Room routine
 * 
 * This routine returns the numbers of characteres the tty driver will accept
 * for queuing to be written. 
 * o return MTU
 */
static int cpc_tty_write_room(struct tty_struct *tty)
{
	st_cpc_tty_area    *cpc_tty; 

	if (!tty || !tty->driver_data ) { 
		CPC_TTY_DBG("hdlcX-tty: no TTY to write room\n");
		return -ENODEV;
	}

	cpc_tty = (st_cpc_tty_area *) tty->driver_data; 

	if ((cpc_tty->tty != tty) ||  (cpc_tty->state != CPC_TTY_ST_OPEN)) { 
		CPC_TTY_DBG("%s: TTY is not opened\n",cpc_tty->name);
		return -ENODEV; 
	}
   	
	CPC_TTY_DBG("%s: write room\n",cpc_tty->name);
	
	return CPC_TTY_MAX_MTU;
} 

/*
 * PC300 TTY chars in buffer routine
 * 
 * This routine returns the chars number in the transmission buffer 
 * o returns 0
 */
static int cpc_tty_chars_in_buffer(struct tty_struct *tty)
{
	st_cpc_tty_area    *cpc_tty; 

	if (!tty || !tty->driver_data ) {
		CPC_TTY_DBG("hdlcX-tty: no TTY to chars in buffer\n");
		return -ENODEV; 
	}

	cpc_tty = (st_cpc_tty_area *) tty->driver_data; 

	if ((cpc_tty->tty != tty) || (cpc_tty->state != CPC_TTY_ST_OPEN)) { 
		CPC_TTY_DBG("%s: TTY is not opened\n",cpc_tty->name);
		return -ENODEV; 
	}
   
	return(0); 
} 

static int pc300_tiocmset(struct tty_struct *tty, struct file *file,
			  unsigned int set, unsigned int clear)
{
	st_cpc_tty_area    *cpc_tty; 

	CPC_TTY_DBG("%s: set:%x clear:%x\n", __func__, set, clear);

	if (!tty || !tty->driver_data ) {
	   	CPC_TTY_DBG("hdlcX-tty: no TTY to chars in buffer\n");	
		return -ENODEV; 
	}

	cpc_tty = (st_cpc_tty_area *) tty->driver_data; 

	if (set & TIOCM_RTS)
		cpc_tty_signal_on(cpc_tty->pc300dev, CTL_RTS);
	if (set & TIOCM_DTR)
		cpc_tty_signal_on(cpc_tty->pc300dev, CTL_DTR);

	if (clear & TIOCM_RTS)
		cpc_tty_signal_off(cpc_tty->pc300dev, CTL_RTS);
	if (clear & TIOCM_DTR)
		cpc_tty_signal_off(cpc_tty->pc300dev, CTL_DTR);

	return 0;
}

static int pc300_tiocmget(struct tty_struct *tty, struct file *file)
{
	unsigned int result;
	unsigned char status;
	unsigned long flags;
	st_cpc_tty_area  *cpc_tty = (st_cpc_tty_area *) tty->driver_data;
	pc300dev_t *pc300dev = cpc_tty->pc300dev;
	pc300ch_t *pc300chan = (pc300ch_t *)pc300dev->chan;
	pc300_t *card = (pc300_t *) pc300chan->card;
	int ch = pc300chan->channel;

	cpc_tty = (st_cpc_tty_area *) tty->driver_data;

	CPC_TTY_DBG("%s-tty: tiocmget\n",
		((struct net_device*)(pc300dev->hdlc))->name);

	CPC_TTY_LOCK(card, flags);
	status = cpc_readb(card->hw.scabase+M_REG(CTL,ch));
	CPC_TTY_UNLOCK(card,flags);

	result = ((status & CTL_DTR) ? TIOCM_DTR : 0) |
		 ((status & CTL_RTS) ? TIOCM_RTS : 0);

	return result;
}

/*
 * PC300 TTY Flush Buffer routine
 *
 * This routine resets the transmission buffer 
 */
static void cpc_tty_flush_buffer(struct tty_struct *tty)
{ 
	st_cpc_tty_area    *cpc_tty; 
	
	if (!tty || !tty->driver_data ) {
	   	CPC_TTY_DBG("hdlcX-tty: no TTY to flush buffer\n");	
		return; 
	}

	cpc_tty = (st_cpc_tty_area *) tty->driver_data; 

	if ((cpc_tty->tty != tty) ||  (cpc_tty->state != CPC_TTY_ST_OPEN)) { 
		CPC_TTY_DBG("%s: TTY is not opened\n",cpc_tty->name);
		return; 
	}

	CPC_TTY_DBG("%s: call wake_up_interruptible\n",cpc_tty->name);

	tty_wakeup(tty);	
	return; 
} 

/*
 * PC300 TTY Hangup routine
 *
 * This routine is called by the tty driver to hangup the interface 
 * o clear DTR signal
 */

static void cpc_tty_hangup(struct tty_struct *tty)
{ 
	st_cpc_tty_area    *cpc_tty; 
	int res;

	if (!tty || !tty->driver_data ) {
		CPC_TTY_DBG("hdlcX-tty: no TTY to hangup\n");	
		return ; 
	}

	cpc_tty = (st_cpc_tty_area *) tty->driver_data; 

	if ((cpc_tty->tty != tty) || (cpc_tty->state != CPC_TTY_ST_OPEN)) {
		CPC_TTY_DBG("%s: TTY is not opened\n",cpc_tty->name);
		return ;
	}
	if (!serial_drv.refcount && cpc_tty_unreg_flag) {
		cpc_tty_unreg_flag = 0;
		CPC_TTY_DBG("%s: unregister the tty driver\n", cpc_tty->name);
		if ((res=tty_unregister_driver(&serial_drv))) { 
			CPC_TTY_DBG("%s: ERROR ->unregister the tty driver error=%d\n",
							cpc_tty->name,res);
		}
	}
	cpc_tty_signal_off(cpc_tty->pc300dev, CTL_DTR);
}

/*
 * PC300 TTY RX work routine
 * This routine treats RX work
 * o verify read buffer
 * o call the line disc. read
 * o free memory
 */
static void cpc_tty_rx_work(struct work_struct *work)
{
	st_cpc_tty_area *cpc_tty;
	unsigned long port;
	int i, j;
	volatile st_cpc_rx_buf *buf;
	char flags=0,flg_rx=1; 
	struct tty_ldisc *ld;

	if (cpc_tty_cnt == 0) return;
	
	for (i=0; (i < 4) && flg_rx ; i++) {
		flg_rx = 0;

		cpc_tty = container_of(work, st_cpc_tty_area, tty_rx_work);
		port = cpc_tty - cpc_tty_area;

		for (j=0; j < CPC_TTY_NPORTS; j++) {
			cpc_tty = &cpc_tty_area[port];
		
			if ((buf=cpc_tty->buf_rx.first) != NULL) {
				if (cpc_tty->tty) {
					ld = tty_ldisc_ref(cpc_tty->tty);
					if (ld) {
						if (ld->ops->receive_buf) {
							CPC_TTY_DBG("%s: call line disc. receive_buf\n",cpc_tty->name);
							ld->ops->receive_buf(cpc_tty->tty, (char *)(buf->data), &flags, buf->size);
						}
						tty_ldisc_deref(ld);
					}
				}	
				cpc_tty->buf_rx.first = cpc_tty->buf_rx.first->next;
				kfree((void *)buf);
				buf = cpc_tty->buf_rx.first;
				flg_rx = 1;
			}
			if (++port == CPC_TTY_NPORTS) port = 0;
		}
	}
} 

/*
 * PC300 TTY RX work routine
 *
 * This routine treats RX interrupt. 
 * o read all frames in card
 * o verify the frame size
 * o read the frame in rx buffer
 */
static void cpc_tty_rx_disc_frame(pc300ch_t *pc300chan)
{
	volatile pcsca_bd_t __iomem * ptdescr; 
	volatile unsigned char status; 
	pc300_t *card = (pc300_t *)pc300chan->card; 
	int ch = pc300chan->channel; 

	/* dma buf read */ 
	ptdescr = (pcsca_bd_t __iomem *)(card->hw.rambase + 
				RX_BD_ADDR(ch, pc300chan->rx_first_bd)); 
	while (pc300chan->rx_first_bd != pc300chan->rx_last_bd) { 
		status = cpc_readb(&ptdescr->status); 
		cpc_writeb(&ptdescr->status, 0); 
		cpc_writeb(&ptdescr->len, 0); 
		pc300chan->rx_first_bd = (pc300chan->rx_first_bd + 1) & 
					(N_DMA_RX_BUF - 1); 
		if (status & DST_EOM) { 
			break; /* end of message */
		}
		ptdescr = (pcsca_bd_t __iomem *)(card->hw.rambase + cpc_readl(&ptdescr->next)); 
	}
}

void cpc_tty_receive(pc300dev_t *pc300dev)
{
	st_cpc_tty_area *cpc_tty; 
	pc300ch_t *pc300chan = (pc300ch_t *)pc300dev->chan; 
	pc300_t *card = (pc300_t *)pc300chan->card; 
	int ch = pc300chan->channel; 
	volatile pcsca_bd_t  __iomem * ptdescr; 
	struct net_device_stats *stats = &pc300dev->dev->stats;
	int rx_len, rx_aux; 
	volatile unsigned char status; 
	unsigned short first_bd = pc300chan->rx_first_bd;
	st_cpc_rx_buf *new = NULL;
	unsigned char dsr_rx;

	if (pc300dev->cpc_tty == NULL) { 
		return; 
	}

	dsr_rx = cpc_readb(card->hw.scabase + DSR_RX(ch));

	cpc_tty = (st_cpc_tty_area *)pc300dev->cpc_tty; 

	while (1) { 
		rx_len = 0;
		ptdescr = (pcsca_bd_t  __iomem *)(card->hw.rambase + RX_BD_ADDR(ch, first_bd));
		while ((status = cpc_readb(&ptdescr->status)) & DST_OSB) {
			rx_len += cpc_readw(&ptdescr->len);
			first_bd = (first_bd + 1) & (N_DMA_RX_BUF - 1);
			if (status & DST_EOM) {
				break;
			}
			ptdescr = (pcsca_bd_t __iomem *)(card->hw.rambase+cpc_readl(&ptdescr->next));
		}
			
		if (!rx_len) { 
			if (dsr_rx & DSR_BOF) {
				/* update EDA */ 
				cpc_writel(card->hw.scabase + DRX_REG(EDAL, ch), 
						RX_BD_ADDR(ch, pc300chan->rx_last_bd)); 
			}
			kfree(new);
			return; 
		}
		
		if (rx_len > CPC_TTY_MAX_MTU) { 
			/* Free RX descriptors */ 
			CPC_TTY_DBG("%s: frame size is invalid.\n",cpc_tty->name);
			stats->rx_errors++; 
			stats->rx_frame_errors++; 
			cpc_tty_rx_disc_frame(pc300chan);
			continue;
		} 
		
		new = kmalloc(rx_len + sizeof(st_cpc_rx_buf), GFP_ATOMIC);
		if (!new) {
			cpc_tty_rx_disc_frame(pc300chan);
			continue;
		}
		
		/* dma buf read */ 
		ptdescr = (pcsca_bd_t __iomem *)(card->hw.rambase + 
				RX_BD_ADDR(ch, pc300chan->rx_first_bd)); 

		rx_len = 0;	/* counter frame size */
		
		while ((status = cpc_readb(&ptdescr->status)) & DST_OSB) {
			rx_aux = cpc_readw(&ptdescr->len);
			if ((status & (DST_OVR | DST_CRC | DST_RBIT |  DST_SHRT | DST_ABT))
				|| (rx_aux > BD_DEF_LEN)) {
				CPC_TTY_DBG("%s: reception error\n", cpc_tty->name);
				stats->rx_errors++; 
				if (status & DST_OVR) { 
					stats->rx_fifo_errors++; 
				}
				if (status & DST_CRC) { 
					stats->rx_crc_errors++; 
				}
				if ((status & (DST_RBIT | DST_SHRT | DST_ABT)) ||
					(rx_aux > BD_DEF_LEN))	{ 
					stats->rx_frame_errors++; 
				} 
				/* discard remainig descriptors used by the bad frame */ 
				CPC_TTY_DBG("%s: reception error - discard descriptors",
						cpc_tty->name);
				cpc_tty_rx_disc_frame(pc300chan);
				rx_len = 0;
				kfree(new);
				new = NULL;
				break; /* read next frame - while(1) */
			}

			if (cpc_tty->state != CPC_TTY_ST_OPEN) {
				/* Free RX descriptors */ 
				cpc_tty_rx_disc_frame(pc300chan);
				stats->rx_dropped++; 
				rx_len = 0; 
				kfree(new);
				new = NULL;
				break; /* read next frame - while(1) */
			}

			/* read the segment of the frame */
			if (rx_aux != 0) {
				memcpy_fromio((new->data + rx_len), 
					(void __iomem *)(card->hw.rambase + 
					 cpc_readl(&ptdescr->ptbuf)), rx_aux);
				rx_len += rx_aux; 
			}
			cpc_writeb(&ptdescr->status,0); 
			cpc_writeb(&ptdescr->len, 0); 
			pc300chan->rx_first_bd = (pc300chan->rx_first_bd + 1) & 
					(N_DMA_RX_BUF -1); 
			if (status & DST_EOM)break;
			
			ptdescr = (pcsca_bd_t __iomem *) (card->hw.rambase + 
					cpc_readl(&ptdescr->next)); 
		}
		/* update pointer */ 
		pc300chan->rx_last_bd = (pc300chan->rx_first_bd - 1) & 
					(N_DMA_RX_BUF - 1) ; 
		if (!(dsr_rx & DSR_BOF)) {
			/* update EDA */ 
			cpc_writel(card->hw.scabase + DRX_REG(EDAL, ch), 
					RX_BD_ADDR(ch, pc300chan->rx_last_bd)); 
		}
		if (rx_len != 0) { 
			stats->rx_bytes += rx_len; 
		
			if (pc300dev->trace_on) { 
				cpc_tty_trace(pc300dev, new->data,rx_len, 'R'); 
			} 
			new->size = rx_len;
			new->next = NULL;
			if (cpc_tty->buf_rx.first == NULL) {
				cpc_tty->buf_rx.first = new;
				cpc_tty->buf_rx.last = new;
			} else {
				cpc_tty->buf_rx.last->next = new;
				cpc_tty->buf_rx.last = new;
			}
			schedule_work(&(cpc_tty->tty_rx_work));
			stats->rx_packets++;
		}
	} 
} 

/*
 * PC300 TTY TX work routine
 * 
 * This routine treats TX interrupt. 
 * o if need call line discipline wakeup
 * o call wake_up_interruptible
 */
static void cpc_tty_tx_work(struct work_struct *work)
{
	st_cpc_tty_area *cpc_tty =
		container_of(work, st_cpc_tty_area, tty_tx_work);
	struct tty_struct *tty; 

	CPC_TTY_DBG("%s: cpc_tty_tx_work init\n",cpc_tty->name);
	
	if ((tty = cpc_tty->tty) == NULL) { 
		CPC_TTY_DBG("%s: the interface is not opened\n",cpc_tty->name);
		return; 
	}
	tty_wakeup(tty);
}

/*
 * PC300 TTY send to card routine
 * 
 * This routine send data to card. 
 * o clear descriptors
 * o write data to DMA buffers
 * o start the transmission
 */
static int cpc_tty_send_to_card(pc300dev_t *dev,void* buf, int len)
{
	pc300ch_t *chan = (pc300ch_t *)dev->chan; 
	pc300_t *card = (pc300_t *)chan->card; 
	int ch = chan->channel; 
	struct net_device_stats *stats = &dev->dev->stats;
	unsigned long flags; 
	volatile pcsca_bd_t __iomem *ptdescr; 
	int i, nchar;
	int tosend = len;
	int nbuf = ((len - 1)/BD_DEF_LEN) + 1;
	unsigned char *pdata=buf;

	CPC_TTY_DBG("%s:cpc_tty_send_to_cars len=%i", 
			(st_cpc_tty_area *)dev->cpc_tty->name,len);	

	if (nbuf >= card->chan[ch].nfree_tx_bd) {
		return 1;
	}
	
	/* write buffer to DMA buffers */ 
	CPC_TTY_DBG("%s: call dma_buf_write\n",
			(st_cpc_tty_area *)dev->cpc_tty->name);	
	for (i = 0 ; i < nbuf ; i++) {
		ptdescr = (pcsca_bd_t __iomem *)(card->hw.rambase + 
			TX_BD_ADDR(ch, card->chan[ch].tx_next_bd));
		nchar = (BD_DEF_LEN > tosend) ? tosend : BD_DEF_LEN;
		if (cpc_readb(&ptdescr->status) & DST_OSB) {
			memcpy_toio((void __iomem *)(card->hw.rambase + 
				cpc_readl(&ptdescr->ptbuf)), 
				&pdata[len - tosend], 
				nchar);
			card->chan[ch].nfree_tx_bd--;
			if ((i + 1) == nbuf) {
				/* This must be the last BD to be used */
				cpc_writeb(&ptdescr->status, DST_EOM);
			} else {
				cpc_writeb(&ptdescr->status, 0);
			}
			cpc_writew(&ptdescr->len, nchar);
		} else {
			CPC_TTY_DBG("%s: error in dma_buf_write\n",
					(st_cpc_tty_area *)dev->cpc_tty->name);	
			stats->tx_dropped++;
			return 1; 
		}
		tosend -= nchar;
		card->chan[ch].tx_next_bd = 
			(card->chan[ch].tx_next_bd + 1) & (N_DMA_TX_BUF - 1);
	}

	if (dev->trace_on) { 
		cpc_tty_trace(dev, buf, len,'T'); 
	}

	/* start transmission */ 
	CPC_TTY_DBG("%s: start transmission\n",
		(st_cpc_tty_area *)dev->cpc_tty->name);	
	
	CPC_TTY_LOCK(card, flags); 
	cpc_writeb(card->hw.scabase + DTX_REG(EDAL, ch), 
			TX_BD_ADDR(ch, chan->tx_next_bd)); 
	cpc_writeb(card->hw.scabase + M_REG(CMD, ch), CMD_TX_ENA); 
	cpc_writeb(card->hw.scabase + DSR_TX(ch), DSR_DE); 

	if (card->hw.type == PC300_TE) { 
		cpc_writeb(card->hw.falcbase + card->hw.cpld_reg2, 
			cpc_readb(card->hw.falcbase + card->hw.cpld_reg2) |
			(CPLD_REG2_FALC_LED1 << (2 * ch))); 
	}
	CPC_TTY_UNLOCK(card, flags); 
	return 0; 
} 

/*
 *	PC300 TTY trace routine
 *
 *  This routine send trace of connection to application. 
 *  o clear descriptors
 *  o write data to DMA buffers
 *  o start the transmission
 */

static void cpc_tty_trace(pc300dev_t *dev, char* buf, int len, char rxtx)
{
	struct sk_buff *skb; 

	if ((skb = dev_alloc_skb(10 + len)) == NULL) { 
		/* out of memory */ 
		CPC_TTY_DBG("%s: tty_trace - out of memory\n", dev->dev->name);
		return; 
	}

	skb_put (skb, 10 + len); 
	skb->dev = dev->dev; 
	skb->protocol = htons(ETH_P_CUST); 
	skb_reset_mac_header(skb);
	skb->pkt_type = PACKET_HOST; 
	skb->len = 10 + len; 

	skb_copy_to_linear_data(skb, dev->dev->name, 5);
	skb->data[5] = '['; 
	skb->data[6] = rxtx; 
	skb->data[7] = ']'; 
	skb->data[8] = ':'; 
	skb->data[9] = ' '; 
	skb_copy_to_linear_data_offset(skb, 10, buf, len);
	netif_rx(skb); 
} 	

/*
 *	PC300 TTY unregister service routine
 *
 *	This routine unregister one interface. 
 */
void cpc_tty_unregister_service(pc300dev_t *pc300dev)
{
	st_cpc_tty_area *cpc_tty; 
	ulong flags;
	int res;

	if ((cpc_tty= (st_cpc_tty_area *) pc300dev->cpc_tty) == NULL) {
		CPC_TTY_DBG("%s: interface is not TTY\n", pc300dev->dev->name);
		return; 
	}
	CPC_TTY_DBG("%s: cpc_tty_unregister_service", cpc_tty->name);

	if (cpc_tty->pc300dev != pc300dev) { 
		CPC_TTY_DBG("%s: invalid tty ptr=%s\n", 
		pc300dev->dev->name, cpc_tty->name);
		return; 
	}

	if (--cpc_tty_cnt == 0) { 
		if (serial_drv.refcount) {
			CPC_TTY_DBG("%s: unregister is not possible, refcount=%d",
							cpc_tty->name, serial_drv.refcount);
			cpc_tty_cnt++;
			cpc_tty_unreg_flag = 1;
			return;
		} else { 
			CPC_TTY_DBG("%s: unregister the tty driver\n", cpc_tty->name);
			if ((res=tty_unregister_driver(&serial_drv))) { 
				CPC_TTY_DBG("%s: ERROR ->unregister the tty driver error=%d\n",
								cpc_tty->name,res);
			}
		}
	}
	CPC_TTY_LOCK(pc300dev->chan->card,flags);
	cpc_tty->tty = NULL; 
	CPC_TTY_UNLOCK(pc300dev->chan->card, flags);
	cpc_tty->tty_minor = 0; 
	cpc_tty->state = CPC_TTY_ST_IDLE; 
} 

/*
 * PC300 TTY trigger poll routine
 * This routine is called by pc300driver to treats Tx interrupt. 
 */
void cpc_tty_trigger_poll(pc300dev_t *pc300dev)
{
	st_cpc_tty_area *cpc_tty = (st_cpc_tty_area *)pc300dev->cpc_tty; 
	if (!cpc_tty) {
		return;
	}
	schedule_work(&(cpc_tty->tty_tx_work)); 
} 

/*
 * PC300 TTY reset var routine
 * This routine is called by pc300driver to init the TTY area. 
 */

void cpc_tty_reset_var(void)
{
	int i ; 

	CPC_TTY_DBG("hdlcX-tty: reset variables\n");
	/* reset  the tty_driver structure - serial_drv */ 
	memset(&serial_drv, 0, sizeof(struct tty_driver));
	for (i=0; i < CPC_TTY_NPORTS; i++){
		memset(&cpc_tty_area[i],0, sizeof(st_cpc_tty_area)); 
	}
}