Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux...
[linux-2.6.git] / drivers / tty / n_r3964.c
1 /* r3964 linediscipline for linux
2  *
3  * -----------------------------------------------------------
4  * Copyright by 
5  * Philips Automation Projects
6  * Kassel (Germany)
7  * -----------------------------------------------------------
8  * This software may be used and distributed according to the terms of
9  * the GNU General Public License, incorporated herein by reference.
10  *
11  * Author:
12  * L. Haag
13  *
14  * $Log: n_r3964.c,v $
15  * Revision 1.10  2001/03/18 13:02:24  dwmw2
16  * Fix timer usage, use spinlocks properly.
17  *
18  * Revision 1.9  2001/03/18 12:52:14  dwmw2
19  * Merge changes in 2.4.2
20  *
21  * Revision 1.8  2000/03/23 14:14:54  dwmw2
22  * Fix race in sleeping in r3964_read()
23  *
24  * Revision 1.7  1999/28/08 11:41:50  dwmw2
25  * Port to 2.3 kernel
26  *
27  * Revision 1.6  1998/09/30 00:40:40  dwmw2
28  * Fixed compilation on 2.0.x kernels
29  * Updated to newly registered tty-ldisc number 9
30  *
31  * Revision 1.5  1998/09/04 21:57:36  dwmw2
32  * Signal handling bug fixes, port to 2.1.x.
33  *
34  * Revision 1.4  1998/04/02 20:26:59  lhaag
35  * select, blocking, ...
36  *
37  * Revision 1.3  1998/02/12 18:58:43  root
38  * fixed some memory leaks
39  * calculation of checksum characters
40  *
41  * Revision 1.2  1998/02/07 13:03:34  root
42  * ioctl read_telegram
43  *
44  * Revision 1.1  1998/02/06 19:21:03  root
45  * Initial revision
46  *
47  *
48  */
49
50 #include <linux/module.h>
51 #include <linux/kernel.h>
52 #include <linux/sched.h>
53 #include <linux/types.h>
54 #include <linux/fcntl.h>
55 #include <linux/interrupt.h>
56 #include <linux/ptrace.h>
57 #include <linux/ioport.h>
58 #include <linux/in.h>
59 #include <linux/slab.h>
60 #include <linux/smp_lock.h>
61 #include <linux/tty.h>
62 #include <linux/errno.h>
63 #include <linux/string.h>       /* used in new tty drivers */
64 #include <linux/signal.h>       /* used in new tty drivers */
65 #include <linux/ioctl.h>
66 #include <linux/n_r3964.h>
67 #include <linux/poll.h>
68 #include <linux/init.h>
69 #include <asm/uaccess.h>
70
71 /*#define DEBUG_QUEUE*/
72
73 /* Log successful handshake and protocol operations  */
74 /*#define DEBUG_PROTO_S*/
75
76 /* Log handshake and protocol errors: */
77 /*#define DEBUG_PROTO_E*/
78
79 /* Log Linediscipline operations (open, close, read, write...): */
80 /*#define DEBUG_LDISC*/
81
82 /* Log module and memory operations (init, cleanup; kmalloc, kfree): */
83 /*#define DEBUG_MODUL*/
84
85 /* Macro helpers for debug output: */
86 #define TRACE(format, args...) printk("r3964: " format "\n" , ## args)
87
88 #ifdef DEBUG_MODUL
89 #define TRACE_M(format, args...) printk("r3964: " format "\n" , ## args)
90 #else
91 #define TRACE_M(fmt, arg...) do {} while (0)
92 #endif
93 #ifdef DEBUG_PROTO_S
94 #define TRACE_PS(format, args...) printk("r3964: " format "\n" , ## args)
95 #else
96 #define TRACE_PS(fmt, arg...) do {} while (0)
97 #endif
98 #ifdef DEBUG_PROTO_E
99 #define TRACE_PE(format, args...) printk("r3964: " format "\n" , ## args)
100 #else
101 #define TRACE_PE(fmt, arg...) do {} while (0)
102 #endif
103 #ifdef DEBUG_LDISC
104 #define TRACE_L(format, args...) printk("r3964: " format "\n" , ## args)
105 #else
106 #define TRACE_L(fmt, arg...) do {} while (0)
107 #endif
108 #ifdef DEBUG_QUEUE
109 #define TRACE_Q(format, args...) printk("r3964: " format "\n" , ## args)
110 #else
111 #define TRACE_Q(fmt, arg...) do {} while (0)
112 #endif
113 static void add_tx_queue(struct r3964_info *, struct r3964_block_header *);
114 static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code);
115 static void put_char(struct r3964_info *pInfo, unsigned char ch);
116 static void trigger_transmit(struct r3964_info *pInfo);
117 static void retry_transmit(struct r3964_info *pInfo);
118 static void transmit_block(struct r3964_info *pInfo);
119 static void receive_char(struct r3964_info *pInfo, const unsigned char c);
120 static void receive_error(struct r3964_info *pInfo, const char flag);
121 static void on_timeout(unsigned long priv);
122 static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg);
123 static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
124                 unsigned char __user * buf);
125 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
126                 int error_code, struct r3964_block_header *pBlock);
127 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
128                 struct r3964_client_info *pClient);
129 static void remove_client_block(struct r3964_info *pInfo,
130                 struct r3964_client_info *pClient);
131
132 static int r3964_open(struct tty_struct *tty);
133 static void r3964_close(struct tty_struct *tty);
134 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
135                 unsigned char __user * buf, size_t nr);
136 static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
137                 const unsigned char *buf, size_t nr);
138 static int r3964_ioctl(struct tty_struct *tty, struct file *file,
139                 unsigned int cmd, unsigned long arg);
140 static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old);
141 static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,
142                 struct poll_table_struct *wait);
143 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
144                 char *fp, int count);
145
146 static struct tty_ldisc_ops tty_ldisc_N_R3964 = {
147         .owner = THIS_MODULE,
148         .magic = TTY_LDISC_MAGIC,
149         .name = "R3964",
150         .open = r3964_open,
151         .close = r3964_close,
152         .read = r3964_read,
153         .write = r3964_write,
154         .ioctl = r3964_ioctl,
155         .set_termios = r3964_set_termios,
156         .poll = r3964_poll,
157         .receive_buf = r3964_receive_buf,
158 };
159
160 static void dump_block(const unsigned char *block, unsigned int length)
161 {
162         unsigned int i, j;
163         char linebuf[16 * 3 + 1];
164
165         for (i = 0; i < length; i += 16) {
166                 for (j = 0; (j < 16) && (j + i < length); j++) {
167                         sprintf(linebuf + 3 * j, "%02x ", block[i + j]);
168                 }
169                 linebuf[3 * j] = '\0';
170                 TRACE_PS("%s", linebuf);
171         }
172 }
173
174 /*************************************************************
175  * Driver initialisation
176  *************************************************************/
177
178 /*************************************************************
179  * Module support routines
180  *************************************************************/
181
182 static void __exit r3964_exit(void)
183 {
184         int status;
185
186         TRACE_M("cleanup_module()");
187
188         status = tty_unregister_ldisc(N_R3964);
189
190         if (status != 0) {
191                 printk(KERN_ERR "r3964: error unregistering linediscipline: "
192                                 "%d\n", status);
193         } else {
194                 TRACE_L("linediscipline successfully unregistered");
195         }
196 }
197
198 static int __init r3964_init(void)
199 {
200         int status;
201
202         printk("r3964: Philips r3964 Driver $Revision: 1.10 $\n");
203
204         /*
205          * Register the tty line discipline
206          */
207
208         status = tty_register_ldisc(N_R3964, &tty_ldisc_N_R3964);
209         if (status == 0) {
210                 TRACE_L("line discipline %d registered", N_R3964);
211                 TRACE_L("flags=%x num=%x", tty_ldisc_N_R3964.flags,
212                         tty_ldisc_N_R3964.num);
213                 TRACE_L("open=%p", tty_ldisc_N_R3964.open);
214                 TRACE_L("tty_ldisc_N_R3964 = %p", &tty_ldisc_N_R3964);
215         } else {
216                 printk(KERN_ERR "r3964: error registering line discipline: "
217                                 "%d\n", status);
218         }
219         return status;
220 }
221
222 module_init(r3964_init);
223 module_exit(r3964_exit);
224
225 /*************************************************************
226  * Protocol implementation routines
227  *************************************************************/
228
229 static void add_tx_queue(struct r3964_info *pInfo,
230                          struct r3964_block_header *pHeader)
231 {
232         unsigned long flags;
233
234         spin_lock_irqsave(&pInfo->lock, flags);
235
236         pHeader->next = NULL;
237
238         if (pInfo->tx_last == NULL) {
239                 pInfo->tx_first = pInfo->tx_last = pHeader;
240         } else {
241                 pInfo->tx_last->next = pHeader;
242                 pInfo->tx_last = pHeader;
243         }
244
245         spin_unlock_irqrestore(&pInfo->lock, flags);
246
247         TRACE_Q("add_tx_queue %p, length %d, tx_first = %p",
248                 pHeader, pHeader->length, pInfo->tx_first);
249 }
250
251 static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code)
252 {
253         struct r3964_block_header *pHeader;
254         unsigned long flags;
255 #ifdef DEBUG_QUEUE
256         struct r3964_block_header *pDump;
257 #endif
258
259         pHeader = pInfo->tx_first;
260
261         if (pHeader == NULL)
262                 return;
263
264 #ifdef DEBUG_QUEUE
265         printk("r3964: remove_from_tx_queue: %p, length %u - ",
266                 pHeader, pHeader->length);
267         for (pDump = pHeader; pDump; pDump = pDump->next)
268                 printk("%p ", pDump);
269         printk("\n");
270 #endif
271
272         if (pHeader->owner) {
273                 if (error_code) {
274                         add_msg(pHeader->owner, R3964_MSG_ACK, 0,
275                                 error_code, NULL);
276                 } else {
277                         add_msg(pHeader->owner, R3964_MSG_ACK, pHeader->length,
278                                 error_code, NULL);
279                 }
280                 wake_up_interruptible(&pInfo->read_wait);
281         }
282
283         spin_lock_irqsave(&pInfo->lock, flags);
284
285         pInfo->tx_first = pHeader->next;
286         if (pInfo->tx_first == NULL) {
287                 pInfo->tx_last = NULL;
288         }
289
290         spin_unlock_irqrestore(&pInfo->lock, flags);
291
292         kfree(pHeader);
293         TRACE_M("remove_from_tx_queue - kfree %p", pHeader);
294
295         TRACE_Q("remove_from_tx_queue: tx_first = %p, tx_last = %p",
296                 pInfo->tx_first, pInfo->tx_last);
297 }
298
299 static void add_rx_queue(struct r3964_info *pInfo,
300                          struct r3964_block_header *pHeader)
301 {
302         unsigned long flags;
303
304         spin_lock_irqsave(&pInfo->lock, flags);
305
306         pHeader->next = NULL;
307
308         if (pInfo->rx_last == NULL) {
309                 pInfo->rx_first = pInfo->rx_last = pHeader;
310         } else {
311                 pInfo->rx_last->next = pHeader;
312                 pInfo->rx_last = pHeader;
313         }
314         pInfo->blocks_in_rx_queue++;
315
316         spin_unlock_irqrestore(&pInfo->lock, flags);
317
318         TRACE_Q("add_rx_queue: %p, length = %d, rx_first = %p, count = %d",
319                 pHeader, pHeader->length,
320                 pInfo->rx_first, pInfo->blocks_in_rx_queue);
321 }
322
323 static void remove_from_rx_queue(struct r3964_info *pInfo,
324                                  struct r3964_block_header *pHeader)
325 {
326         unsigned long flags;
327         struct r3964_block_header *pFind;
328
329         if (pHeader == NULL)
330                 return;
331
332         TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
333                 pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
334         TRACE_Q("remove_from_rx_queue: %p, length %u",
335                 pHeader, pHeader->length);
336
337         spin_lock_irqsave(&pInfo->lock, flags);
338
339         if (pInfo->rx_first == pHeader) {
340                 /* Remove the first block in the linked list: */
341                 pInfo->rx_first = pHeader->next;
342
343                 if (pInfo->rx_first == NULL) {
344                         pInfo->rx_last = NULL;
345                 }
346                 pInfo->blocks_in_rx_queue--;
347         } else {
348                 /* Find block to remove: */
349                 for (pFind = pInfo->rx_first; pFind; pFind = pFind->next) {
350                         if (pFind->next == pHeader) {
351                                 /* Got it. */
352                                 pFind->next = pHeader->next;
353                                 pInfo->blocks_in_rx_queue--;
354                                 if (pFind->next == NULL) {
355                                         /* Oh, removed the last one! */
356                                         pInfo->rx_last = pFind;
357                                 }
358                                 break;
359                         }
360                 }
361         }
362
363         spin_unlock_irqrestore(&pInfo->lock, flags);
364
365         kfree(pHeader);
366         TRACE_M("remove_from_rx_queue - kfree %p", pHeader);
367
368         TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
369                 pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
370 }
371
372 static void put_char(struct r3964_info *pInfo, unsigned char ch)
373 {
374         struct tty_struct *tty = pInfo->tty;
375         /* FIXME: put_char should not be called from an IRQ */
376         tty_put_char(tty, ch);
377         pInfo->bcc ^= ch;
378 }
379
380 static void flush(struct r3964_info *pInfo)
381 {
382         struct tty_struct *tty = pInfo->tty;
383
384         if (tty == NULL || tty->ops->flush_chars == NULL)
385                 return;
386         tty->ops->flush_chars(tty);
387 }
388
389 static void trigger_transmit(struct r3964_info *pInfo)
390 {
391         unsigned long flags;
392
393         spin_lock_irqsave(&pInfo->lock, flags);
394
395         if ((pInfo->state == R3964_IDLE) && (pInfo->tx_first != NULL)) {
396                 pInfo->state = R3964_TX_REQUEST;
397                 pInfo->nRetry = 0;
398                 pInfo->flags &= ~R3964_ERROR;
399                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
400
401                 spin_unlock_irqrestore(&pInfo->lock, flags);
402
403                 TRACE_PS("trigger_transmit - sent STX");
404
405                 put_char(pInfo, STX);
406                 flush(pInfo);
407
408                 pInfo->bcc = 0;
409         } else {
410                 spin_unlock_irqrestore(&pInfo->lock, flags);
411         }
412 }
413
414 static void retry_transmit(struct r3964_info *pInfo)
415 {
416         if (pInfo->nRetry < R3964_MAX_RETRIES) {
417                 TRACE_PE("transmission failed. Retry #%d", pInfo->nRetry);
418                 pInfo->bcc = 0;
419                 put_char(pInfo, STX);
420                 flush(pInfo);
421                 pInfo->state = R3964_TX_REQUEST;
422                 pInfo->nRetry++;
423                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
424         } else {
425                 TRACE_PE("transmission failed after %d retries",
426                          R3964_MAX_RETRIES);
427
428                 remove_from_tx_queue(pInfo, R3964_TX_FAIL);
429
430                 put_char(pInfo, NAK);
431                 flush(pInfo);
432                 pInfo->state = R3964_IDLE;
433
434                 trigger_transmit(pInfo);
435         }
436 }
437
438 static void transmit_block(struct r3964_info *pInfo)
439 {
440         struct tty_struct *tty = pInfo->tty;
441         struct r3964_block_header *pBlock = pInfo->tx_first;
442         int room = 0;
443
444         if (tty == NULL || pBlock == NULL) {
445                 return;
446         }
447
448         room = tty_write_room(tty);
449
450         TRACE_PS("transmit_block %p, room %d, length %d",
451                  pBlock, room, pBlock->length);
452
453         while (pInfo->tx_position < pBlock->length) {
454                 if (room < 2)
455                         break;
456
457                 if (pBlock->data[pInfo->tx_position] == DLE) {
458                         /* send additional DLE char: */
459                         put_char(pInfo, DLE);
460                 }
461                 put_char(pInfo, pBlock->data[pInfo->tx_position++]);
462
463                 room--;
464         }
465
466         if ((pInfo->tx_position == pBlock->length) && (room >= 3)) {
467                 put_char(pInfo, DLE);
468                 put_char(pInfo, ETX);
469                 if (pInfo->flags & R3964_BCC) {
470                         put_char(pInfo, pInfo->bcc);
471                 }
472                 pInfo->state = R3964_WAIT_FOR_TX_ACK;
473                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
474         }
475         flush(pInfo);
476 }
477
478 static void on_receive_block(struct r3964_info *pInfo)
479 {
480         unsigned int length;
481         struct r3964_client_info *pClient;
482         struct r3964_block_header *pBlock;
483
484         length = pInfo->rx_position;
485
486         /* compare byte checksum characters: */
487         if (pInfo->flags & R3964_BCC) {
488                 if (pInfo->bcc != pInfo->last_rx) {
489                         TRACE_PE("checksum error - got %x but expected %x",
490                                  pInfo->last_rx, pInfo->bcc);
491                         pInfo->flags |= R3964_CHECKSUM;
492                 }
493         }
494
495         /* check for errors (parity, overrun,...): */
496         if (pInfo->flags & R3964_ERROR) {
497                 TRACE_PE("on_receive_block - transmission failed error %x",
498                          pInfo->flags & R3964_ERROR);
499
500                 put_char(pInfo, NAK);
501                 flush(pInfo);
502                 if (pInfo->nRetry < R3964_MAX_RETRIES) {
503                         pInfo->state = R3964_WAIT_FOR_RX_REPEAT;
504                         pInfo->nRetry++;
505                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_RX_PANIC);
506                 } else {
507                         TRACE_PE("on_receive_block - failed after max retries");
508                         pInfo->state = R3964_IDLE;
509                 }
510                 return;
511         }
512
513         /* received block; submit DLE: */
514         put_char(pInfo, DLE);
515         flush(pInfo);
516         del_timer_sync(&pInfo->tmr);
517         TRACE_PS(" rx success: got %d chars", length);
518
519         /* prepare struct r3964_block_header: */
520         pBlock = kmalloc(length + sizeof(struct r3964_block_header),
521                         GFP_KERNEL);
522         TRACE_M("on_receive_block - kmalloc %p", pBlock);
523
524         if (pBlock == NULL)
525                 return;
526
527         pBlock->length = length;
528         pBlock->data = ((unsigned char *)pBlock) +
529                         sizeof(struct r3964_block_header);
530         pBlock->locks = 0;
531         pBlock->next = NULL;
532         pBlock->owner = NULL;
533
534         memcpy(pBlock->data, pInfo->rx_buf, length);
535
536         /* queue block into rx_queue: */
537         add_rx_queue(pInfo, pBlock);
538
539         /* notify attached client processes: */
540         for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
541                 if (pClient->sig_flags & R3964_SIG_DATA) {
542                         add_msg(pClient, R3964_MSG_DATA, length, R3964_OK,
543                                 pBlock);
544                 }
545         }
546         wake_up_interruptible(&pInfo->read_wait);
547
548         pInfo->state = R3964_IDLE;
549
550         trigger_transmit(pInfo);
551 }
552
553 static void receive_char(struct r3964_info *pInfo, const unsigned char c)
554 {
555         switch (pInfo->state) {
556         case R3964_TX_REQUEST:
557                 if (c == DLE) {
558                         TRACE_PS("TX_REQUEST - got DLE");
559
560                         pInfo->state = R3964_TRANSMITTING;
561                         pInfo->tx_position = 0;
562
563                         transmit_block(pInfo);
564                 } else if (c == STX) {
565                         if (pInfo->nRetry == 0) {
566                                 TRACE_PE("TX_REQUEST - init conflict");
567                                 if (pInfo->priority == R3964_SLAVE) {
568                                         goto start_receiving;
569                                 }
570                         } else {
571                                 TRACE_PE("TX_REQUEST - secondary init "
572                                         "conflict!? Switching to SLAVE mode "
573                                         "for next rx.");
574                                 goto start_receiving;
575                         }
576                 } else {
577                         TRACE_PE("TX_REQUEST - char != DLE: %x", c);
578                         retry_transmit(pInfo);
579                 }
580                 break;
581         case R3964_TRANSMITTING:
582                 if (c == NAK) {
583                         TRACE_PE("TRANSMITTING - got NAK");
584                         retry_transmit(pInfo);
585                 } else {
586                         TRACE_PE("TRANSMITTING - got invalid char");
587
588                         pInfo->state = R3964_WAIT_ZVZ_BEFORE_TX_RETRY;
589                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
590                 }
591                 break;
592         case R3964_WAIT_FOR_TX_ACK:
593                 if (c == DLE) {
594                         TRACE_PS("WAIT_FOR_TX_ACK - got DLE");
595                         remove_from_tx_queue(pInfo, R3964_OK);
596
597                         pInfo->state = R3964_IDLE;
598                         trigger_transmit(pInfo);
599                 } else {
600                         retry_transmit(pInfo);
601                 }
602                 break;
603         case R3964_WAIT_FOR_RX_REPEAT:
604                 /* FALLTHROUGH */
605         case R3964_IDLE:
606                 if (c == STX) {
607                         /* Prevent rx_queue from overflow: */
608                         if (pInfo->blocks_in_rx_queue >=
609                             R3964_MAX_BLOCKS_IN_RX_QUEUE) {
610                                 TRACE_PE("IDLE - got STX but no space in "
611                                                 "rx_queue!");
612                                 pInfo->state = R3964_WAIT_FOR_RX_BUF;
613                                 mod_timer(&pInfo->tmr,
614                                           jiffies + R3964_TO_NO_BUF);
615                                 break;
616                         }
617 start_receiving:
618                         /* Ok, start receiving: */
619                         TRACE_PS("IDLE - got STX");
620                         pInfo->rx_position = 0;
621                         pInfo->last_rx = 0;
622                         pInfo->flags &= ~R3964_ERROR;
623                         pInfo->state = R3964_RECEIVING;
624                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
625                         pInfo->nRetry = 0;
626                         put_char(pInfo, DLE);
627                         flush(pInfo);
628                         pInfo->bcc = 0;
629                 }
630                 break;
631         case R3964_RECEIVING:
632                 if (pInfo->rx_position < RX_BUF_SIZE) {
633                         pInfo->bcc ^= c;
634
635                         if (c == DLE) {
636                                 if (pInfo->last_rx == DLE) {
637                                         pInfo->last_rx = 0;
638                                         goto char_to_buf;
639                                 }
640                                 pInfo->last_rx = DLE;
641                                 break;
642                         } else if ((c == ETX) && (pInfo->last_rx == DLE)) {
643                                 if (pInfo->flags & R3964_BCC) {
644                                         pInfo->state = R3964_WAIT_FOR_BCC;
645                                         mod_timer(&pInfo->tmr,
646                                                   jiffies + R3964_TO_ZVZ);
647                                 } else {
648                                         on_receive_block(pInfo);
649                                 }
650                         } else {
651                                 pInfo->last_rx = c;
652 char_to_buf:
653                                 pInfo->rx_buf[pInfo->rx_position++] = c;
654                                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
655                         }
656                 }
657                 /* else: overflow-msg? BUF_SIZE>MTU; should not happen? */
658                 break;
659         case R3964_WAIT_FOR_BCC:
660                 pInfo->last_rx = c;
661                 on_receive_block(pInfo);
662                 break;
663         }
664 }
665
666 static void receive_error(struct r3964_info *pInfo, const char flag)
667 {
668         switch (flag) {
669         case TTY_NORMAL:
670                 break;
671         case TTY_BREAK:
672                 TRACE_PE("received break");
673                 pInfo->flags |= R3964_BREAK;
674                 break;
675         case TTY_PARITY:
676                 TRACE_PE("parity error");
677                 pInfo->flags |= R3964_PARITY;
678                 break;
679         case TTY_FRAME:
680                 TRACE_PE("frame error");
681                 pInfo->flags |= R3964_FRAME;
682                 break;
683         case TTY_OVERRUN:
684                 TRACE_PE("frame overrun");
685                 pInfo->flags |= R3964_OVERRUN;
686                 break;
687         default:
688                 TRACE_PE("receive_error - unknown flag %d", flag);
689                 pInfo->flags |= R3964_UNKNOWN;
690                 break;
691         }
692 }
693
694 static void on_timeout(unsigned long priv)
695 {
696         struct r3964_info *pInfo = (void *)priv;
697
698         switch (pInfo->state) {
699         case R3964_TX_REQUEST:
700                 TRACE_PE("TX_REQUEST - timeout");
701                 retry_transmit(pInfo);
702                 break;
703         case R3964_WAIT_ZVZ_BEFORE_TX_RETRY:
704                 put_char(pInfo, NAK);
705                 flush(pInfo);
706                 retry_transmit(pInfo);
707                 break;
708         case R3964_WAIT_FOR_TX_ACK:
709                 TRACE_PE("WAIT_FOR_TX_ACK - timeout");
710                 retry_transmit(pInfo);
711                 break;
712         case R3964_WAIT_FOR_RX_BUF:
713                 TRACE_PE("WAIT_FOR_RX_BUF - timeout");
714                 put_char(pInfo, NAK);
715                 flush(pInfo);
716                 pInfo->state = R3964_IDLE;
717                 break;
718         case R3964_RECEIVING:
719                 TRACE_PE("RECEIVING - timeout after %d chars",
720                          pInfo->rx_position);
721                 put_char(pInfo, NAK);
722                 flush(pInfo);
723                 pInfo->state = R3964_IDLE;
724                 break;
725         case R3964_WAIT_FOR_RX_REPEAT:
726                 TRACE_PE("WAIT_FOR_RX_REPEAT - timeout");
727                 pInfo->state = R3964_IDLE;
728                 break;
729         case R3964_WAIT_FOR_BCC:
730                 TRACE_PE("WAIT_FOR_BCC - timeout");
731                 put_char(pInfo, NAK);
732                 flush(pInfo);
733                 pInfo->state = R3964_IDLE;
734                 break;
735         }
736 }
737
738 static struct r3964_client_info *findClient(struct r3964_info *pInfo,
739                 struct pid *pid)
740 {
741         struct r3964_client_info *pClient;
742
743         for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
744                 if (pClient->pid == pid) {
745                         return pClient;
746                 }
747         }
748         return NULL;
749 }
750
751 static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg)
752 {
753         struct r3964_client_info *pClient;
754         struct r3964_client_info **ppClient;
755         struct r3964_message *pMsg;
756
757         if ((arg & R3964_SIG_ALL) == 0) {
758                 /* Remove client from client list */
759                 for (ppClient = &pInfo->firstClient; *ppClient;
760                      ppClient = &(*ppClient)->next) {
761                         pClient = *ppClient;
762
763                         if (pClient->pid == pid) {
764                                 TRACE_PS("removing client %d from client list",
765                                          pid_nr(pid));
766                                 *ppClient = pClient->next;
767                                 while (pClient->msg_count) {
768                                         pMsg = remove_msg(pInfo, pClient);
769                                         if (pMsg) {
770                                                 kfree(pMsg);
771                                                 TRACE_M("enable_signals - msg "
772                                                         "kfree %p", pMsg);
773                                         }
774                                 }
775                                 put_pid(pClient->pid);
776                                 kfree(pClient);
777                                 TRACE_M("enable_signals - kfree %p", pClient);
778                                 return 0;
779                         }
780                 }
781                 return -EINVAL;
782         } else {
783                 pClient = findClient(pInfo, pid);
784                 if (pClient) {
785                         /* update signal options */
786                         pClient->sig_flags = arg;
787                 } else {
788                         /* add client to client list */
789                         pClient = kmalloc(sizeof(struct r3964_client_info),
790                                         GFP_KERNEL);
791                         TRACE_M("enable_signals - kmalloc %p", pClient);
792                         if (pClient == NULL)
793                                 return -ENOMEM;
794
795                         TRACE_PS("add client %d to client list", pid_nr(pid));
796                         spin_lock_init(&pClient->lock);
797                         pClient->sig_flags = arg;
798                         pClient->pid = get_pid(pid);
799                         pClient->next = pInfo->firstClient;
800                         pClient->first_msg = NULL;
801                         pClient->last_msg = NULL;
802                         pClient->next_block_to_read = NULL;
803                         pClient->msg_count = 0;
804                         pInfo->firstClient = pClient;
805                 }
806         }
807
808         return 0;
809 }
810
811 static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
812                          unsigned char __user * buf)
813 {
814         struct r3964_client_info *pClient;
815         struct r3964_block_header *block;
816
817         if (!buf) {
818                 return -EINVAL;
819         }
820
821         pClient = findClient(pInfo, pid);
822         if (pClient == NULL) {
823                 return -EINVAL;
824         }
825
826         block = pClient->next_block_to_read;
827         if (!block) {
828                 return 0;
829         } else {
830                 if (copy_to_user(buf, block->data, block->length))
831                         return -EFAULT;
832
833                 remove_client_block(pInfo, pClient);
834                 return block->length;
835         }
836
837         return -EINVAL;
838 }
839
840 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
841                 int error_code, struct r3964_block_header *pBlock)
842 {
843         struct r3964_message *pMsg;
844         unsigned long flags;
845
846         if (pClient->msg_count < R3964_MAX_MSG_COUNT - 1) {
847 queue_the_message:
848
849                 pMsg = kmalloc(sizeof(struct r3964_message),
850                                 error_code ? GFP_ATOMIC : GFP_KERNEL);
851                 TRACE_M("add_msg - kmalloc %p", pMsg);
852                 if (pMsg == NULL) {
853                         return;
854                 }
855
856                 spin_lock_irqsave(&pClient->lock, flags);
857
858                 pMsg->msg_id = msg_id;
859                 pMsg->arg = arg;
860                 pMsg->error_code = error_code;
861                 pMsg->block = pBlock;
862                 pMsg->next = NULL;
863
864                 if (pClient->last_msg == NULL) {
865                         pClient->first_msg = pClient->last_msg = pMsg;
866                 } else {
867                         pClient->last_msg->next = pMsg;
868                         pClient->last_msg = pMsg;
869                 }
870
871                 pClient->msg_count++;
872
873                 if (pBlock != NULL) {
874                         pBlock->locks++;
875                 }
876                 spin_unlock_irqrestore(&pClient->lock, flags);
877         } else {
878                 if ((pClient->last_msg->msg_id == R3964_MSG_ACK)
879                     && (pClient->last_msg->error_code == R3964_OVERFLOW)) {
880                         pClient->last_msg->arg++;
881                         TRACE_PE("add_msg - inc prev OVERFLOW-msg");
882                 } else {
883                         msg_id = R3964_MSG_ACK;
884                         arg = 0;
885                         error_code = R3964_OVERFLOW;
886                         pBlock = NULL;
887                         TRACE_PE("add_msg - queue OVERFLOW-msg");
888                         goto queue_the_message;
889                 }
890         }
891         /* Send SIGIO signal to client process: */
892         if (pClient->sig_flags & R3964_USE_SIGIO) {
893                 kill_pid(pClient->pid, SIGIO, 1);
894         }
895 }
896
897 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
898                                         struct r3964_client_info *pClient)
899 {
900         struct r3964_message *pMsg = NULL;
901         unsigned long flags;
902
903         if (pClient->first_msg) {
904                 spin_lock_irqsave(&pClient->lock, flags);
905
906                 pMsg = pClient->first_msg;
907                 pClient->first_msg = pMsg->next;
908                 if (pClient->first_msg == NULL) {
909                         pClient->last_msg = NULL;
910                 }
911
912                 pClient->msg_count--;
913                 if (pMsg->block) {
914                         remove_client_block(pInfo, pClient);
915                         pClient->next_block_to_read = pMsg->block;
916                 }
917                 spin_unlock_irqrestore(&pClient->lock, flags);
918         }
919         return pMsg;
920 }
921
922 static void remove_client_block(struct r3964_info *pInfo,
923                                 struct r3964_client_info *pClient)
924 {
925         struct r3964_block_header *block;
926
927         TRACE_PS("remove_client_block PID %d", pid_nr(pClient->pid));
928
929         block = pClient->next_block_to_read;
930         if (block) {
931                 block->locks--;
932                 if (block->locks == 0) {
933                         remove_from_rx_queue(pInfo, block);
934                 }
935         }
936         pClient->next_block_to_read = NULL;
937 }
938
939 /*************************************************************
940  * Line discipline routines
941  *************************************************************/
942
943 static int r3964_open(struct tty_struct *tty)
944 {
945         struct r3964_info *pInfo;
946
947         TRACE_L("open");
948         TRACE_L("tty=%p, PID=%d, disc_data=%p",
949                 tty, current->pid, tty->disc_data);
950
951         pInfo = kmalloc(sizeof(struct r3964_info), GFP_KERNEL);
952         TRACE_M("r3964_open - info kmalloc %p", pInfo);
953
954         if (!pInfo) {
955                 printk(KERN_ERR "r3964: failed to alloc info structure\n");
956                 return -ENOMEM;
957         }
958
959         pInfo->rx_buf = kmalloc(RX_BUF_SIZE, GFP_KERNEL);
960         TRACE_M("r3964_open - rx_buf kmalloc %p", pInfo->rx_buf);
961
962         if (!pInfo->rx_buf) {
963                 printk(KERN_ERR "r3964: failed to alloc receive buffer\n");
964                 kfree(pInfo);
965                 TRACE_M("r3964_open - info kfree %p", pInfo);
966                 return -ENOMEM;
967         }
968
969         pInfo->tx_buf = kmalloc(TX_BUF_SIZE, GFP_KERNEL);
970         TRACE_M("r3964_open - tx_buf kmalloc %p", pInfo->tx_buf);
971
972         if (!pInfo->tx_buf) {
973                 printk(KERN_ERR "r3964: failed to alloc transmit buffer\n");
974                 kfree(pInfo->rx_buf);
975                 TRACE_M("r3964_open - rx_buf kfree %p", pInfo->rx_buf);
976                 kfree(pInfo);
977                 TRACE_M("r3964_open - info kfree %p", pInfo);
978                 return -ENOMEM;
979         }
980
981         spin_lock_init(&pInfo->lock);
982         pInfo->tty = tty;
983         init_waitqueue_head(&pInfo->read_wait);
984         pInfo->priority = R3964_MASTER;
985         pInfo->rx_first = pInfo->rx_last = NULL;
986         pInfo->tx_first = pInfo->tx_last = NULL;
987         pInfo->rx_position = 0;
988         pInfo->tx_position = 0;
989         pInfo->last_rx = 0;
990         pInfo->blocks_in_rx_queue = 0;
991         pInfo->firstClient = NULL;
992         pInfo->state = R3964_IDLE;
993         pInfo->flags = R3964_DEBUG;
994         pInfo->nRetry = 0;
995
996         tty->disc_data = pInfo;
997         tty->receive_room = 65536;
998
999         setup_timer(&pInfo->tmr, on_timeout, (unsigned long)pInfo);
1000
1001         return 0;
1002 }
1003
1004 static void r3964_close(struct tty_struct *tty)
1005 {
1006         struct r3964_info *pInfo = tty->disc_data;
1007         struct r3964_client_info *pClient, *pNext;
1008         struct r3964_message *pMsg;
1009         struct r3964_block_header *pHeader, *pNextHeader;
1010         unsigned long flags;
1011
1012         TRACE_L("close");
1013
1014         /*
1015          * Make sure that our task queue isn't activated.  If it
1016          * is, take it out of the linked list.
1017          */
1018         del_timer_sync(&pInfo->tmr);
1019
1020         /* Remove client-structs and message queues: */
1021         pClient = pInfo->firstClient;
1022         while (pClient) {
1023                 pNext = pClient->next;
1024                 while (pClient->msg_count) {
1025                         pMsg = remove_msg(pInfo, pClient);
1026                         if (pMsg) {
1027                                 kfree(pMsg);
1028                                 TRACE_M("r3964_close - msg kfree %p", pMsg);
1029                         }
1030                 }
1031                 put_pid(pClient->pid);
1032                 kfree(pClient);
1033                 TRACE_M("r3964_close - client kfree %p", pClient);
1034                 pClient = pNext;
1035         }
1036         /* Remove jobs from tx_queue: */
1037         spin_lock_irqsave(&pInfo->lock, flags);
1038         pHeader = pInfo->tx_first;
1039         pInfo->tx_first = pInfo->tx_last = NULL;
1040         spin_unlock_irqrestore(&pInfo->lock, flags);
1041
1042         while (pHeader) {
1043                 pNextHeader = pHeader->next;
1044                 kfree(pHeader);
1045                 pHeader = pNextHeader;
1046         }
1047
1048         /* Free buffers: */
1049         wake_up_interruptible(&pInfo->read_wait);
1050         kfree(pInfo->rx_buf);
1051         TRACE_M("r3964_close - rx_buf kfree %p", pInfo->rx_buf);
1052         kfree(pInfo->tx_buf);
1053         TRACE_M("r3964_close - tx_buf kfree %p", pInfo->tx_buf);
1054         kfree(pInfo);
1055         TRACE_M("r3964_close - info kfree %p", pInfo);
1056 }
1057
1058 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
1059                           unsigned char __user * buf, size_t nr)
1060 {
1061         struct r3964_info *pInfo = tty->disc_data;
1062         struct r3964_client_info *pClient;
1063         struct r3964_message *pMsg;
1064         struct r3964_client_message theMsg;
1065         int ret;
1066
1067         TRACE_L("read()");
1068
1069         tty_lock();
1070
1071         pClient = findClient(pInfo, task_pid(current));
1072         if (pClient) {
1073                 pMsg = remove_msg(pInfo, pClient);
1074                 if (pMsg == NULL) {
1075                         /* no messages available. */
1076                         if (file->f_flags & O_NONBLOCK) {
1077                                 ret = -EAGAIN;
1078                                 goto unlock;
1079                         }
1080                         /* block until there is a message: */
1081                         wait_event_interruptible_tty(pInfo->read_wait,
1082                                         (pMsg = remove_msg(pInfo, pClient)));
1083                 }
1084
1085                 /* If we still haven't got a message, we must have been signalled */
1086
1087                 if (!pMsg) {
1088                         ret = -EINTR;
1089                         goto unlock;
1090                 }
1091
1092                 /* deliver msg to client process: */
1093                 theMsg.msg_id = pMsg->msg_id;
1094                 theMsg.arg = pMsg->arg;
1095                 theMsg.error_code = pMsg->error_code;
1096                 ret = sizeof(struct r3964_client_message);
1097
1098                 kfree(pMsg);
1099                 TRACE_M("r3964_read - msg kfree %p", pMsg);
1100
1101                 if (copy_to_user(buf, &theMsg, ret)) {
1102                         ret = -EFAULT;
1103                         goto unlock;
1104                 }
1105
1106                 TRACE_PS("read - return %d", ret);
1107                 goto unlock;
1108         }
1109         ret = -EPERM;
1110 unlock:
1111         tty_unlock();
1112         return ret;
1113 }
1114
1115 static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
1116                            const unsigned char *data, size_t count)
1117 {
1118         struct r3964_info *pInfo = tty->disc_data;
1119         struct r3964_block_header *pHeader;
1120         struct r3964_client_info *pClient;
1121         unsigned char *new_data;
1122
1123         TRACE_L("write request, %d characters", count);
1124 /* 
1125  * Verify the pointers 
1126  */
1127
1128         if (!pInfo)
1129                 return -EIO;
1130
1131 /*
1132  * Ensure that the caller does not wish to send too much.
1133  */
1134         if (count > R3964_MTU) {
1135                 if (pInfo->flags & R3964_DEBUG) {
1136                         TRACE_L(KERN_WARNING "r3964_write: truncating user "
1137                                 "packet from %u to mtu %d", count, R3964_MTU);
1138                 }
1139                 count = R3964_MTU;
1140         }
1141 /*
1142  * Allocate a buffer for the data and copy it from the buffer with header prepended
1143  */
1144         new_data = kmalloc(count + sizeof(struct r3964_block_header),
1145                         GFP_KERNEL);
1146         TRACE_M("r3964_write - kmalloc %p", new_data);
1147         if (new_data == NULL) {
1148                 if (pInfo->flags & R3964_DEBUG) {
1149                         printk(KERN_ERR "r3964_write: no memory\n");
1150                 }
1151                 return -ENOSPC;
1152         }
1153
1154         pHeader = (struct r3964_block_header *)new_data;
1155         pHeader->data = new_data + sizeof(struct r3964_block_header);
1156         pHeader->length = count;
1157         pHeader->locks = 0;
1158         pHeader->owner = NULL;
1159
1160         tty_lock();
1161
1162         pClient = findClient(pInfo, task_pid(current));
1163         if (pClient) {
1164                 pHeader->owner = pClient;
1165         }
1166
1167         memcpy(pHeader->data, data, count);     /* We already verified this */
1168
1169         if (pInfo->flags & R3964_DEBUG) {
1170                 dump_block(pHeader->data, count);
1171         }
1172
1173 /*
1174  * Add buffer to transmit-queue:
1175  */
1176         add_tx_queue(pInfo, pHeader);
1177         trigger_transmit(pInfo);
1178
1179         tty_unlock();
1180
1181         return 0;
1182 }
1183
1184 static int r3964_ioctl(struct tty_struct *tty, struct file *file,
1185                 unsigned int cmd, unsigned long arg)
1186 {
1187         struct r3964_info *pInfo = tty->disc_data;
1188         if (pInfo == NULL)
1189                 return -EINVAL;
1190         switch (cmd) {
1191         case R3964_ENABLE_SIGNALS:
1192                 return enable_signals(pInfo, task_pid(current), arg);
1193         case R3964_SETPRIORITY:
1194                 if (arg < R3964_MASTER || arg > R3964_SLAVE)
1195                         return -EINVAL;
1196                 pInfo->priority = arg & 0xff;
1197                 return 0;
1198         case R3964_USE_BCC:
1199                 if (arg)
1200                         pInfo->flags |= R3964_BCC;
1201                 else
1202                         pInfo->flags &= ~R3964_BCC;
1203                 return 0;
1204         case R3964_READ_TELEGRAM:
1205                 return read_telegram(pInfo, task_pid(current),
1206                                 (unsigned char __user *)arg);
1207         default:
1208                 return -ENOIOCTLCMD;
1209         }
1210 }
1211
1212 static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old)
1213 {
1214         TRACE_L("set_termios");
1215 }
1216
1217 /* Called without the kernel lock held - fine */
1218 static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,
1219                         struct poll_table_struct *wait)
1220 {
1221         struct r3964_info *pInfo = tty->disc_data;
1222         struct r3964_client_info *pClient;
1223         struct r3964_message *pMsg = NULL;
1224         unsigned long flags;
1225         int result = POLLOUT;
1226
1227         TRACE_L("POLL");
1228
1229         pClient = findClient(pInfo, task_pid(current));
1230         if (pClient) {
1231                 poll_wait(file, &pInfo->read_wait, wait);
1232                 spin_lock_irqsave(&pInfo->lock, flags);
1233                 pMsg = pClient->first_msg;
1234                 spin_unlock_irqrestore(&pInfo->lock, flags);
1235                 if (pMsg)
1236                         result |= POLLIN | POLLRDNORM;
1237         } else {
1238                 result = -EINVAL;
1239         }
1240         return result;
1241 }
1242
1243 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1244                         char *fp, int count)
1245 {
1246         struct r3964_info *pInfo = tty->disc_data;
1247         const unsigned char *p;
1248         char *f, flags = 0;
1249         int i;
1250
1251         for (i = count, p = cp, f = fp; i; i--, p++) {
1252                 if (f)
1253                         flags = *f++;
1254                 if (flags == TTY_NORMAL) {
1255                         receive_char(pInfo, *p);
1256                 } else {
1257                         receive_error(pInfo, flags);
1258                 }
1259
1260         }
1261 }
1262
1263 MODULE_LICENSE("GPL");
1264 MODULE_ALIAS_LDISC(N_R3964);