Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
[linux-2.6] / drivers / char / n_r3964.c
1 /* r3964 linediscipline for linux
2  *
3  * -----------------------------------------------------------
4  * Copyright by 
5  * Philips Automation Projects
6  * Kassel (Germany)
7  * http://www.pap-philips.de
8  * -----------------------------------------------------------
9  * This software may be used and distributed according to the terms of
10  * the GNU General Public License, incorporated herein by reference.
11  *
12  * Author:
13  * L. Haag
14  *
15  * $Log: n_r3964.c,v $
16  * Revision 1.10  2001/03/18 13:02:24  dwmw2
17  * Fix timer usage, use spinlocks properly.
18  *
19  * Revision 1.9  2001/03/18 12:52:14  dwmw2
20  * Merge changes in 2.4.2
21  *
22  * Revision 1.8  2000/03/23 14:14:54  dwmw2
23  * Fix race in sleeping in r3964_read()
24  *
25  * Revision 1.7  1999/28/08 11:41:50  dwmw2
26  * Port to 2.3 kernel
27  *
28  * Revision 1.6  1998/09/30 00:40:40  dwmw2
29  * Fixed compilation on 2.0.x kernels
30  * Updated to newly registered tty-ldisc number 9
31  *
32  * Revision 1.5  1998/09/04 21:57:36  dwmw2
33  * Signal handling bug fixes, port to 2.1.x.
34  *
35  * Revision 1.4  1998/04/02 20:26:59  lhaag
36  * select, blocking, ...
37  *
38  * Revision 1.3  1998/02/12 18:58:43  root
39  * fixed some memory leaks
40  * calculation of checksum characters
41  *
42  * Revision 1.2  1998/02/07 13:03:34  root
43  * ioctl read_telegram
44  *
45  * Revision 1.1  1998/02/06 19:21:03  root
46  * Initial revision
47  *
48  *
49  */
50
51 #include <linux/module.h>
52 #include <linux/kernel.h>
53 #include <linux/sched.h>
54 #include <linux/types.h>
55 #include <linux/fcntl.h>
56 #include <linux/interrupt.h>
57 #include <linux/ptrace.h>
58 #include <linux/ioport.h>
59 #include <linux/in.h>
60 #include <linux/slab.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
376         if (tty == NULL)
377                 return;
378
379         /* FIXME: put_char should not be called from an IRQ */
380         if (tty->ops->put_char) {
381                 tty->ops->put_char(tty, ch);
382         }
383         pInfo->bcc ^= ch;
384 }
385
386 static void flush(struct r3964_info *pInfo)
387 {
388         struct tty_struct *tty = pInfo->tty;
389
390         if (tty == NULL || tty->ops->flush_chars == NULL)
391                 return;
392         tty->ops->flush_chars(tty);
393 }
394
395 static void trigger_transmit(struct r3964_info *pInfo)
396 {
397         unsigned long flags;
398
399         spin_lock_irqsave(&pInfo->lock, flags);
400
401         if ((pInfo->state == R3964_IDLE) && (pInfo->tx_first != NULL)) {
402                 pInfo->state = R3964_TX_REQUEST;
403                 pInfo->nRetry = 0;
404                 pInfo->flags &= ~R3964_ERROR;
405                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
406
407                 spin_unlock_irqrestore(&pInfo->lock, flags);
408
409                 TRACE_PS("trigger_transmit - sent STX");
410
411                 put_char(pInfo, STX);
412                 flush(pInfo);
413
414                 pInfo->bcc = 0;
415         } else {
416                 spin_unlock_irqrestore(&pInfo->lock, flags);
417         }
418 }
419
420 static void retry_transmit(struct r3964_info *pInfo)
421 {
422         if (pInfo->nRetry < R3964_MAX_RETRIES) {
423                 TRACE_PE("transmission failed. Retry #%d", pInfo->nRetry);
424                 pInfo->bcc = 0;
425                 put_char(pInfo, STX);
426                 flush(pInfo);
427                 pInfo->state = R3964_TX_REQUEST;
428                 pInfo->nRetry++;
429                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
430         } else {
431                 TRACE_PE("transmission failed after %d retries",
432                          R3964_MAX_RETRIES);
433
434                 remove_from_tx_queue(pInfo, R3964_TX_FAIL);
435
436                 put_char(pInfo, NAK);
437                 flush(pInfo);
438                 pInfo->state = R3964_IDLE;
439
440                 trigger_transmit(pInfo);
441         }
442 }
443
444 static void transmit_block(struct r3964_info *pInfo)
445 {
446         struct tty_struct *tty = pInfo->tty;
447         struct r3964_block_header *pBlock = pInfo->tx_first;
448         int room = 0;
449
450         if (tty == NULL || pBlock == NULL) {
451                 return;
452         }
453
454         room = tty_write_room(tty);
455
456         TRACE_PS("transmit_block %p, room %d, length %d",
457                  pBlock, room, pBlock->length);
458
459         while (pInfo->tx_position < pBlock->length) {
460                 if (room < 2)
461                         break;
462
463                 if (pBlock->data[pInfo->tx_position] == DLE) {
464                         /* send additional DLE char: */
465                         put_char(pInfo, DLE);
466                 }
467                 put_char(pInfo, pBlock->data[pInfo->tx_position++]);
468
469                 room--;
470         }
471
472         if ((pInfo->tx_position == pBlock->length) && (room >= 3)) {
473                 put_char(pInfo, DLE);
474                 put_char(pInfo, ETX);
475                 if (pInfo->flags & R3964_BCC) {
476                         put_char(pInfo, pInfo->bcc);
477                 }
478                 pInfo->state = R3964_WAIT_FOR_TX_ACK;
479                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
480         }
481         flush(pInfo);
482 }
483
484 static void on_receive_block(struct r3964_info *pInfo)
485 {
486         unsigned int length;
487         struct r3964_client_info *pClient;
488         struct r3964_block_header *pBlock;
489
490         length = pInfo->rx_position;
491
492         /* compare byte checksum characters: */
493         if (pInfo->flags & R3964_BCC) {
494                 if (pInfo->bcc != pInfo->last_rx) {
495                         TRACE_PE("checksum error - got %x but expected %x",
496                                  pInfo->last_rx, pInfo->bcc);
497                         pInfo->flags |= R3964_CHECKSUM;
498                 }
499         }
500
501         /* check for errors (parity, overrun,...): */
502         if (pInfo->flags & R3964_ERROR) {
503                 TRACE_PE("on_receive_block - transmission failed error %x",
504                          pInfo->flags & R3964_ERROR);
505
506                 put_char(pInfo, NAK);
507                 flush(pInfo);
508                 if (pInfo->nRetry < R3964_MAX_RETRIES) {
509                         pInfo->state = R3964_WAIT_FOR_RX_REPEAT;
510                         pInfo->nRetry++;
511                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_RX_PANIC);
512                 } else {
513                         TRACE_PE("on_receive_block - failed after max retries");
514                         pInfo->state = R3964_IDLE;
515                 }
516                 return;
517         }
518
519         /* received block; submit DLE: */
520         put_char(pInfo, DLE);
521         flush(pInfo);
522         del_timer_sync(&pInfo->tmr);
523         TRACE_PS(" rx success: got %d chars", length);
524
525         /* prepare struct r3964_block_header: */
526         pBlock = kmalloc(length + sizeof(struct r3964_block_header),
527                         GFP_KERNEL);
528         TRACE_M("on_receive_block - kmalloc %p", pBlock);
529
530         if (pBlock == NULL)
531                 return;
532
533         pBlock->length = length;
534         pBlock->data = ((unsigned char *)pBlock) +
535                         sizeof(struct r3964_block_header);
536         pBlock->locks = 0;
537         pBlock->next = NULL;
538         pBlock->owner = NULL;
539
540         memcpy(pBlock->data, pInfo->rx_buf, length);
541
542         /* queue block into rx_queue: */
543         add_rx_queue(pInfo, pBlock);
544
545         /* notify attached client processes: */
546         for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
547                 if (pClient->sig_flags & R3964_SIG_DATA) {
548                         add_msg(pClient, R3964_MSG_DATA, length, R3964_OK,
549                                 pBlock);
550                 }
551         }
552         wake_up_interruptible(&pInfo->read_wait);
553
554         pInfo->state = R3964_IDLE;
555
556         trigger_transmit(pInfo);
557 }
558
559 static void receive_char(struct r3964_info *pInfo, const unsigned char c)
560 {
561         switch (pInfo->state) {
562         case R3964_TX_REQUEST:
563                 if (c == DLE) {
564                         TRACE_PS("TX_REQUEST - got DLE");
565
566                         pInfo->state = R3964_TRANSMITTING;
567                         pInfo->tx_position = 0;
568
569                         transmit_block(pInfo);
570                 } else if (c == STX) {
571                         if (pInfo->nRetry == 0) {
572                                 TRACE_PE("TX_REQUEST - init conflict");
573                                 if (pInfo->priority == R3964_SLAVE) {
574                                         goto start_receiving;
575                                 }
576                         } else {
577                                 TRACE_PE("TX_REQUEST - secondary init "
578                                         "conflict!? Switching to SLAVE mode "
579                                         "for next rx.");
580                                 goto start_receiving;
581                         }
582                 } else {
583                         TRACE_PE("TX_REQUEST - char != DLE: %x", c);
584                         retry_transmit(pInfo);
585                 }
586                 break;
587         case R3964_TRANSMITTING:
588                 if (c == NAK) {
589                         TRACE_PE("TRANSMITTING - got NAK");
590                         retry_transmit(pInfo);
591                 } else {
592                         TRACE_PE("TRANSMITTING - got invalid char");
593
594                         pInfo->state = R3964_WAIT_ZVZ_BEFORE_TX_RETRY;
595                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
596                 }
597                 break;
598         case R3964_WAIT_FOR_TX_ACK:
599                 if (c == DLE) {
600                         TRACE_PS("WAIT_FOR_TX_ACK - got DLE");
601                         remove_from_tx_queue(pInfo, R3964_OK);
602
603                         pInfo->state = R3964_IDLE;
604                         trigger_transmit(pInfo);
605                 } else {
606                         retry_transmit(pInfo);
607                 }
608                 break;
609         case R3964_WAIT_FOR_RX_REPEAT:
610                 /* FALLTROUGH */
611         case R3964_IDLE:
612                 if (c == STX) {
613                         /* Prevent rx_queue from overflow: */
614                         if (pInfo->blocks_in_rx_queue >=
615                             R3964_MAX_BLOCKS_IN_RX_QUEUE) {
616                                 TRACE_PE("IDLE - got STX but no space in "
617                                                 "rx_queue!");
618                                 pInfo->state = R3964_WAIT_FOR_RX_BUF;
619                                 mod_timer(&pInfo->tmr,
620                                           jiffies + R3964_TO_NO_BUF);
621                                 break;
622                         }
623 start_receiving:
624                         /* Ok, start receiving: */
625                         TRACE_PS("IDLE - got STX");
626                         pInfo->rx_position = 0;
627                         pInfo->last_rx = 0;
628                         pInfo->flags &= ~R3964_ERROR;
629                         pInfo->state = R3964_RECEIVING;
630                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
631                         pInfo->nRetry = 0;
632                         put_char(pInfo, DLE);
633                         flush(pInfo);
634                         pInfo->bcc = 0;
635                 }
636                 break;
637         case R3964_RECEIVING:
638                 if (pInfo->rx_position < RX_BUF_SIZE) {
639                         pInfo->bcc ^= c;
640
641                         if (c == DLE) {
642                                 if (pInfo->last_rx == DLE) {
643                                         pInfo->last_rx = 0;
644                                         goto char_to_buf;
645                                 }
646                                 pInfo->last_rx = DLE;
647                                 break;
648                         } else if ((c == ETX) && (pInfo->last_rx == DLE)) {
649                                 if (pInfo->flags & R3964_BCC) {
650                                         pInfo->state = R3964_WAIT_FOR_BCC;
651                                         mod_timer(&pInfo->tmr,
652                                                   jiffies + R3964_TO_ZVZ);
653                                 } else {
654                                         on_receive_block(pInfo);
655                                 }
656                         } else {
657                                 pInfo->last_rx = c;
658 char_to_buf:
659                                 pInfo->rx_buf[pInfo->rx_position++] = c;
660                                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
661                         }
662                 }
663                 /* else: overflow-msg? BUF_SIZE>MTU; should not happen? */
664                 break;
665         case R3964_WAIT_FOR_BCC:
666                 pInfo->last_rx = c;
667                 on_receive_block(pInfo);
668                 break;
669         }
670 }
671
672 static void receive_error(struct r3964_info *pInfo, const char flag)
673 {
674         switch (flag) {
675         case TTY_NORMAL:
676                 break;
677         case TTY_BREAK:
678                 TRACE_PE("received break");
679                 pInfo->flags |= R3964_BREAK;
680                 break;
681         case TTY_PARITY:
682                 TRACE_PE("parity error");
683                 pInfo->flags |= R3964_PARITY;
684                 break;
685         case TTY_FRAME:
686                 TRACE_PE("frame error");
687                 pInfo->flags |= R3964_FRAME;
688                 break;
689         case TTY_OVERRUN:
690                 TRACE_PE("frame overrun");
691                 pInfo->flags |= R3964_OVERRUN;
692                 break;
693         default:
694                 TRACE_PE("receive_error - unknown flag %d", flag);
695                 pInfo->flags |= R3964_UNKNOWN;
696                 break;
697         }
698 }
699
700 static void on_timeout(unsigned long priv)
701 {
702         struct r3964_info *pInfo = (void *)priv;
703
704         switch (pInfo->state) {
705         case R3964_TX_REQUEST:
706                 TRACE_PE("TX_REQUEST - timeout");
707                 retry_transmit(pInfo);
708                 break;
709         case R3964_WAIT_ZVZ_BEFORE_TX_RETRY:
710                 put_char(pInfo, NAK);
711                 flush(pInfo);
712                 retry_transmit(pInfo);
713                 break;
714         case R3964_WAIT_FOR_TX_ACK:
715                 TRACE_PE("WAIT_FOR_TX_ACK - timeout");
716                 retry_transmit(pInfo);
717                 break;
718         case R3964_WAIT_FOR_RX_BUF:
719                 TRACE_PE("WAIT_FOR_RX_BUF - timeout");
720                 put_char(pInfo, NAK);
721                 flush(pInfo);
722                 pInfo->state = R3964_IDLE;
723                 break;
724         case R3964_RECEIVING:
725                 TRACE_PE("RECEIVING - timeout after %d chars",
726                          pInfo->rx_position);
727                 put_char(pInfo, NAK);
728                 flush(pInfo);
729                 pInfo->state = R3964_IDLE;
730                 break;
731         case R3964_WAIT_FOR_RX_REPEAT:
732                 TRACE_PE("WAIT_FOR_RX_REPEAT - timeout");
733                 pInfo->state = R3964_IDLE;
734                 break;
735         case R3964_WAIT_FOR_BCC:
736                 TRACE_PE("WAIT_FOR_BCC - timeout");
737                 put_char(pInfo, NAK);
738                 flush(pInfo);
739                 pInfo->state = R3964_IDLE;
740                 break;
741         }
742 }
743
744 static struct r3964_client_info *findClient(struct r3964_info *pInfo,
745                 struct pid *pid)
746 {
747         struct r3964_client_info *pClient;
748
749         for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
750                 if (pClient->pid == pid) {
751                         return pClient;
752                 }
753         }
754         return NULL;
755 }
756
757 static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg)
758 {
759         struct r3964_client_info *pClient;
760         struct r3964_client_info **ppClient;
761         struct r3964_message *pMsg;
762
763         if ((arg & R3964_SIG_ALL) == 0) {
764                 /* Remove client from client list */
765                 for (ppClient = &pInfo->firstClient; *ppClient;
766                      ppClient = &(*ppClient)->next) {
767                         pClient = *ppClient;
768
769                         if (pClient->pid == pid) {
770                                 TRACE_PS("removing client %d from client list",
771                                          pid_nr(pid));
772                                 *ppClient = pClient->next;
773                                 while (pClient->msg_count) {
774                                         pMsg = remove_msg(pInfo, pClient);
775                                         if (pMsg) {
776                                                 kfree(pMsg);
777                                                 TRACE_M("enable_signals - msg "
778                                                         "kfree %p", pMsg);
779                                         }
780                                 }
781                                 put_pid(pClient->pid);
782                                 kfree(pClient);
783                                 TRACE_M("enable_signals - kfree %p", pClient);
784                                 return 0;
785                         }
786                 }
787                 return -EINVAL;
788         } else {
789                 pClient = findClient(pInfo, pid);
790                 if (pClient) {
791                         /* update signal options */
792                         pClient->sig_flags = arg;
793                 } else {
794                         /* add client to client list */
795                         pClient = kmalloc(sizeof(struct r3964_client_info),
796                                         GFP_KERNEL);
797                         TRACE_M("enable_signals - kmalloc %p", pClient);
798                         if (pClient == NULL)
799                                 return -ENOMEM;
800
801                         TRACE_PS("add client %d to client list", pid_nr(pid));
802                         spin_lock_init(&pClient->lock);
803                         pClient->sig_flags = arg;
804                         pClient->pid = get_pid(pid);
805                         pClient->next = pInfo->firstClient;
806                         pClient->first_msg = NULL;
807                         pClient->last_msg = NULL;
808                         pClient->next_block_to_read = NULL;
809                         pClient->msg_count = 0;
810                         pInfo->firstClient = pClient;
811                 }
812         }
813
814         return 0;
815 }
816
817 static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
818                          unsigned char __user * buf)
819 {
820         struct r3964_client_info *pClient;
821         struct r3964_block_header *block;
822
823         if (!buf) {
824                 return -EINVAL;
825         }
826
827         pClient = findClient(pInfo, pid);
828         if (pClient == NULL) {
829                 return -EINVAL;
830         }
831
832         block = pClient->next_block_to_read;
833         if (!block) {
834                 return 0;
835         } else {
836                 if (copy_to_user(buf, block->data, block->length))
837                         return -EFAULT;
838
839                 remove_client_block(pInfo, pClient);
840                 return block->length;
841         }
842
843         return -EINVAL;
844 }
845
846 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
847                 int error_code, struct r3964_block_header *pBlock)
848 {
849         struct r3964_message *pMsg;
850         unsigned long flags;
851
852         if (pClient->msg_count < R3964_MAX_MSG_COUNT - 1) {
853 queue_the_message:
854
855                 pMsg = kmalloc(sizeof(struct r3964_message),
856                                 error_code ? GFP_ATOMIC : GFP_KERNEL);
857                 TRACE_M("add_msg - kmalloc %p", pMsg);
858                 if (pMsg == NULL) {
859                         return;
860                 }
861
862                 spin_lock_irqsave(&pClient->lock, flags);
863
864                 pMsg->msg_id = msg_id;
865                 pMsg->arg = arg;
866                 pMsg->error_code = error_code;
867                 pMsg->block = pBlock;
868                 pMsg->next = NULL;
869
870                 if (pClient->last_msg == NULL) {
871                         pClient->first_msg = pClient->last_msg = pMsg;
872                 } else {
873                         pClient->last_msg->next = pMsg;
874                         pClient->last_msg = pMsg;
875                 }
876
877                 pClient->msg_count++;
878
879                 if (pBlock != NULL) {
880                         pBlock->locks++;
881                 }
882                 spin_unlock_irqrestore(&pClient->lock, flags);
883         } else {
884                 if ((pClient->last_msg->msg_id == R3964_MSG_ACK)
885                     && (pClient->last_msg->error_code == R3964_OVERFLOW)) {
886                         pClient->last_msg->arg++;
887                         TRACE_PE("add_msg - inc prev OVERFLOW-msg");
888                 } else {
889                         msg_id = R3964_MSG_ACK;
890                         arg = 0;
891                         error_code = R3964_OVERFLOW;
892                         pBlock = NULL;
893                         TRACE_PE("add_msg - queue OVERFLOW-msg");
894                         goto queue_the_message;
895                 }
896         }
897         /* Send SIGIO signal to client process: */
898         if (pClient->sig_flags & R3964_USE_SIGIO) {
899                 kill_pid(pClient->pid, SIGIO, 1);
900         }
901 }
902
903 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
904                                         struct r3964_client_info *pClient)
905 {
906         struct r3964_message *pMsg = NULL;
907         unsigned long flags;
908
909         if (pClient->first_msg) {
910                 spin_lock_irqsave(&pClient->lock, flags);
911
912                 pMsg = pClient->first_msg;
913                 pClient->first_msg = pMsg->next;
914                 if (pClient->first_msg == NULL) {
915                         pClient->last_msg = NULL;
916                 }
917
918                 pClient->msg_count--;
919                 if (pMsg->block) {
920                         remove_client_block(pInfo, pClient);
921                         pClient->next_block_to_read = pMsg->block;
922                 }
923                 spin_unlock_irqrestore(&pClient->lock, flags);
924         }
925         return pMsg;
926 }
927
928 static void remove_client_block(struct r3964_info *pInfo,
929                                 struct r3964_client_info *pClient)
930 {
931         struct r3964_block_header *block;
932
933         TRACE_PS("remove_client_block PID %d", pid_nr(pClient->pid));
934
935         block = pClient->next_block_to_read;
936         if (block) {
937                 block->locks--;
938                 if (block->locks == 0) {
939                         remove_from_rx_queue(pInfo, block);
940                 }
941         }
942         pClient->next_block_to_read = NULL;
943 }
944
945 /*************************************************************
946  * Line discipline routines
947  *************************************************************/
948
949 static int r3964_open(struct tty_struct *tty)
950 {
951         struct r3964_info *pInfo;
952
953         TRACE_L("open");
954         TRACE_L("tty=%p, PID=%d, disc_data=%p",
955                 tty, current->pid, tty->disc_data);
956
957         pInfo = kmalloc(sizeof(struct r3964_info), GFP_KERNEL);
958         TRACE_M("r3964_open - info kmalloc %p", pInfo);
959
960         if (!pInfo) {
961                 printk(KERN_ERR "r3964: failed to alloc info structure\n");
962                 return -ENOMEM;
963         }
964
965         pInfo->rx_buf = kmalloc(RX_BUF_SIZE, GFP_KERNEL);
966         TRACE_M("r3964_open - rx_buf kmalloc %p", pInfo->rx_buf);
967
968         if (!pInfo->rx_buf) {
969                 printk(KERN_ERR "r3964: failed to alloc receive buffer\n");
970                 kfree(pInfo);
971                 TRACE_M("r3964_open - info kfree %p", pInfo);
972                 return -ENOMEM;
973         }
974
975         pInfo->tx_buf = kmalloc(TX_BUF_SIZE, GFP_KERNEL);
976         TRACE_M("r3964_open - tx_buf kmalloc %p", pInfo->tx_buf);
977
978         if (!pInfo->tx_buf) {
979                 printk(KERN_ERR "r3964: failed to alloc transmit buffer\n");
980                 kfree(pInfo->rx_buf);
981                 TRACE_M("r3964_open - rx_buf kfree %p", pInfo->rx_buf);
982                 kfree(pInfo);
983                 TRACE_M("r3964_open - info kfree %p", pInfo);
984                 return -ENOMEM;
985         }
986
987         spin_lock_init(&pInfo->lock);
988         pInfo->tty = tty;
989         init_waitqueue_head(&pInfo->read_wait);
990         pInfo->priority = R3964_MASTER;
991         pInfo->rx_first = pInfo->rx_last = NULL;
992         pInfo->tx_first = pInfo->tx_last = NULL;
993         pInfo->rx_position = 0;
994         pInfo->tx_position = 0;
995         pInfo->last_rx = 0;
996         pInfo->blocks_in_rx_queue = 0;
997         pInfo->firstClient = NULL;
998         pInfo->state = R3964_IDLE;
999         pInfo->flags = R3964_DEBUG;
1000         pInfo->nRetry = 0;
1001
1002         tty->disc_data = pInfo;
1003         tty->receive_room = 65536;
1004
1005         setup_timer(&pInfo->tmr, on_timeout, (unsigned long)pInfo);
1006
1007         return 0;
1008 }
1009
1010 static void r3964_close(struct tty_struct *tty)
1011 {
1012         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1013         struct r3964_client_info *pClient, *pNext;
1014         struct r3964_message *pMsg;
1015         struct r3964_block_header *pHeader, *pNextHeader;
1016         unsigned long flags;
1017
1018         TRACE_L("close");
1019
1020         /*
1021          * Make sure that our task queue isn't activated.  If it
1022          * is, take it out of the linked list.
1023          */
1024         del_timer_sync(&pInfo->tmr);
1025
1026         /* Remove client-structs and message queues: */
1027         pClient = pInfo->firstClient;
1028         while (pClient) {
1029                 pNext = pClient->next;
1030                 while (pClient->msg_count) {
1031                         pMsg = remove_msg(pInfo, pClient);
1032                         if (pMsg) {
1033                                 kfree(pMsg);
1034                                 TRACE_M("r3964_close - msg kfree %p", pMsg);
1035                         }
1036                 }
1037                 put_pid(pClient->pid);
1038                 kfree(pClient);
1039                 TRACE_M("r3964_close - client kfree %p", pClient);
1040                 pClient = pNext;
1041         }
1042         /* Remove jobs from tx_queue: */
1043         spin_lock_irqsave(&pInfo->lock, flags);
1044         pHeader = pInfo->tx_first;
1045         pInfo->tx_first = pInfo->tx_last = NULL;
1046         spin_unlock_irqrestore(&pInfo->lock, flags);
1047
1048         while (pHeader) {
1049                 pNextHeader = pHeader->next;
1050                 kfree(pHeader);
1051                 pHeader = pNextHeader;
1052         }
1053
1054         /* Free buffers: */
1055         wake_up_interruptible(&pInfo->read_wait);
1056         kfree(pInfo->rx_buf);
1057         TRACE_M("r3964_close - rx_buf kfree %p", pInfo->rx_buf);
1058         kfree(pInfo->tx_buf);
1059         TRACE_M("r3964_close - tx_buf kfree %p", pInfo->tx_buf);
1060         kfree(pInfo);
1061         TRACE_M("r3964_close - info kfree %p", pInfo);
1062 }
1063
1064 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
1065                           unsigned char __user * buf, size_t nr)
1066 {
1067         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1068         struct r3964_client_info *pClient;
1069         struct r3964_message *pMsg;
1070         struct r3964_client_message theMsg;
1071         int count;
1072
1073         TRACE_L("read()");
1074
1075         lock_kernel();
1076
1077         pClient = findClient(pInfo, task_pid(current));
1078         if (pClient) {
1079                 pMsg = remove_msg(pInfo, pClient);
1080                 if (pMsg == NULL) {
1081                         /* no messages available. */
1082                         if (file->f_flags & O_NONBLOCK) {
1083                                 unlock_kernel();
1084                                 return -EAGAIN;
1085                         }
1086                         /* block until there is a message: */
1087                         wait_event_interruptible(pInfo->read_wait,
1088                                         (pMsg = remove_msg(pInfo, pClient)));
1089                 }
1090
1091                 /* If we still haven't got a message, we must have been signalled */
1092
1093                 if (!pMsg) {
1094                         unlock_kernel();
1095                         return -EINTR;
1096                 }
1097
1098                 /* deliver msg to client process: */
1099                 theMsg.msg_id = pMsg->msg_id;
1100                 theMsg.arg = pMsg->arg;
1101                 theMsg.error_code = pMsg->error_code;
1102                 count = sizeof(struct r3964_client_message);
1103
1104                 kfree(pMsg);
1105                 TRACE_M("r3964_read - msg kfree %p", pMsg);
1106
1107                 if (copy_to_user(buf, &theMsg, count)) {
1108                         unlock_kernel();
1109                         return -EFAULT;
1110                 }
1111
1112                 TRACE_PS("read - return %d", count);
1113                 return count;
1114         }
1115         unlock_kernel();
1116         return -EPERM;
1117 }
1118
1119 static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
1120                            const unsigned char *data, size_t count)
1121 {
1122         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1123         struct r3964_block_header *pHeader;
1124         struct r3964_client_info *pClient;
1125         unsigned char *new_data;
1126
1127         TRACE_L("write request, %d characters", count);
1128 /* 
1129  * Verify the pointers 
1130  */
1131
1132         if (!pInfo)
1133                 return -EIO;
1134
1135 /*
1136  * Ensure that the caller does not wish to send too much.
1137  */
1138         if (count > R3964_MTU) {
1139                 if (pInfo->flags & R3964_DEBUG) {
1140                         TRACE_L(KERN_WARNING "r3964_write: truncating user "
1141                                 "packet from %u to mtu %d", count, R3964_MTU);
1142                 }
1143                 count = R3964_MTU;
1144         }
1145 /*
1146  * Allocate a buffer for the data and copy it from the buffer with header prepended
1147  */
1148         new_data = kmalloc(count + sizeof(struct r3964_block_header),
1149                         GFP_KERNEL);
1150         TRACE_M("r3964_write - kmalloc %p", new_data);
1151         if (new_data == NULL) {
1152                 if (pInfo->flags & R3964_DEBUG) {
1153                         printk(KERN_ERR "r3964_write: no memory\n");
1154                 }
1155                 return -ENOSPC;
1156         }
1157
1158         pHeader = (struct r3964_block_header *)new_data;
1159         pHeader->data = new_data + sizeof(struct r3964_block_header);
1160         pHeader->length = count;
1161         pHeader->locks = 0;
1162         pHeader->owner = NULL;
1163
1164         lock_kernel();
1165
1166         pClient = findClient(pInfo, task_pid(current));
1167         if (pClient) {
1168                 pHeader->owner = pClient;
1169         }
1170
1171         memcpy(pHeader->data, data, count);     /* We already verified this */
1172
1173         if (pInfo->flags & R3964_DEBUG) {
1174                 dump_block(pHeader->data, count);
1175         }
1176
1177 /*
1178  * Add buffer to transmit-queue:
1179  */
1180         add_tx_queue(pInfo, pHeader);
1181         trigger_transmit(pInfo);
1182
1183         unlock_kernel();
1184
1185         return 0;
1186 }
1187
1188 static int r3964_ioctl(struct tty_struct *tty, struct file *file,
1189                 unsigned int cmd, unsigned long arg)
1190 {
1191         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1192         if (pInfo == NULL)
1193                 return -EINVAL;
1194         switch (cmd) {
1195         case R3964_ENABLE_SIGNALS:
1196                 return enable_signals(pInfo, task_pid(current), arg);
1197         case R3964_SETPRIORITY:
1198                 if (arg < R3964_MASTER || arg > R3964_SLAVE)
1199                         return -EINVAL;
1200                 pInfo->priority = arg & 0xff;
1201                 return 0;
1202         case R3964_USE_BCC:
1203                 if (arg)
1204                         pInfo->flags |= R3964_BCC;
1205                 else
1206                         pInfo->flags &= ~R3964_BCC;
1207                 return 0;
1208         case R3964_READ_TELEGRAM:
1209                 return read_telegram(pInfo, task_pid(current),
1210                                 (unsigned char __user *)arg);
1211         default:
1212                 return -ENOIOCTLCMD;
1213         }
1214 }
1215
1216 static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old)
1217 {
1218         TRACE_L("set_termios");
1219 }
1220
1221 /* Called without the kernel lock held - fine */
1222 static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,
1223                         struct poll_table_struct *wait)
1224 {
1225         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1226         struct r3964_client_info *pClient;
1227         struct r3964_message *pMsg = NULL;
1228         unsigned long flags;
1229         int result = POLLOUT;
1230
1231         TRACE_L("POLL");
1232
1233         pClient = findClient(pInfo, task_pid(current));
1234         if (pClient) {
1235                 poll_wait(file, &pInfo->read_wait, wait);
1236                 spin_lock_irqsave(&pInfo->lock, flags);
1237                 pMsg = pClient->first_msg;
1238                 spin_unlock_irqrestore(&pInfo->lock, flags);
1239                 if (pMsg)
1240                         result |= POLLIN | POLLRDNORM;
1241         } else {
1242                 result = -EINVAL;
1243         }
1244         return result;
1245 }
1246
1247 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1248                         char *fp, int count)
1249 {
1250         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1251         const unsigned char *p;
1252         char *f, flags = 0;
1253         int i;
1254
1255         for (i = count, p = cp, f = fp; i; i--, p++) {
1256                 if (f)
1257                         flags = *f++;
1258                 if (flags == TTY_NORMAL) {
1259                         receive_char(pInfo, *p);
1260                 } else {
1261                         receive_error(pInfo, flags);
1262                 }
1263
1264         }
1265 }
1266
1267 MODULE_LICENSE("GPL");
1268 MODULE_ALIAS_LDISC(N_R3964);