1 // SPDX-License-Identifier: GPL-1.0+
2 /* r3964 linediscipline for linux
3 *
4 * -----------------------------------------------------------
5 * Copyright by
6 * Philips Automation Projects
7 * Kassel (Germany)
8 * -----------------------------------------------------------
9 * Author:
10 * L. Haag
11 *
12 * $Log: n_r3964.c,v $
13 * Revision 1.10 2001/03/18 13:02:24 dwmw2
14 * Fix timer usage, use spinlocks properly.
15 *
16 * Revision 1.9 2001/03/18 12:52:14 dwmw2
17 * Merge changes in 2.4.2
18 *
19 * Revision 1.8 2000/03/23 14:14:54 dwmw2
20 * Fix race in sleeping in r3964_read()
21 *
22 * Revision 1.7 1999/28/08 11:41:50 dwmw2
23 * Port to 2.3 kernel
24 *
25 * Revision 1.6 1998/09/30 00:40:40 dwmw2
26 * Fixed compilation on 2.0.x kernels
27 * Updated to newly registered tty-ldisc number 9
28 *
29 * Revision 1.5 1998/09/04 21:57:36 dwmw2
30 * Signal handling bug fixes, port to 2.1.x.
31 *
32 * Revision 1.4 1998/04/02 20:26:59 lhaag
33 * select, blocking, ...
34 *
35 * Revision 1.3 1998/02/12 18:58:43 root
36 * fixed some memory leaks
37 * calculation of checksum characters
38 *
39 * Revision 1.2 1998/02/07 13:03:34 root
40 * ioctl read_telegram
41 *
42 * Revision 1.1 1998/02/06 19:21:03 root
43 * Initial revision
44 *
45 *
46 */
47
48 #include <linux/module.h>
49 #include <linux/kernel.h>
50 #include <linux/sched.h>
51 #include <linux/types.h>
52 #include <linux/fcntl.h>
53 #include <linux/interrupt.h>
54 #include <linux/ptrace.h>
55 #include <linux/ioport.h>
56 #include <linux/in.h>
57 #include <linux/slab.h>
58 #include <linux/tty.h>
59 #include <linux/errno.h>
60 #include <linux/string.h> /* used in new tty drivers */
61 #include <linux/signal.h> /* used in new tty drivers */
62 #include <linux/ioctl.h>
63 #include <linux/n_r3964.h>
64 #include <linux/poll.h>
65 #include <linux/init.h>
66 #include <linux/uaccess.h>
67
68 /*#define DEBUG_QUEUE*/
69
70 /* Log successful handshake and protocol operations */
71 /*#define DEBUG_PROTO_S*/
72
73 /* Log handshake and protocol errors: */
74 /*#define DEBUG_PROTO_E*/
75
76 /* Log Linediscipline operations (open, close, read, write...): */
77 /*#define DEBUG_LDISC*/
78
79 /* Log module and memory operations (init, cleanup; kmalloc, kfree): */
80 /*#define DEBUG_MODUL*/
81
82 /* Macro helpers for debug output: */
83 #define TRACE(format, args...) printk("r3964: " format "\n" , ## args)
84
85 #ifdef DEBUG_MODUL
86 #define TRACE_M(format, args...) printk("r3964: " format "\n" , ## args)
87 #else
88 #define TRACE_M(fmt, arg...) do {} while (0)
89 #endif
90 #ifdef DEBUG_PROTO_S
91 #define TRACE_PS(format, args...) printk("r3964: " format "\n" , ## args)
92 #else
93 #define TRACE_PS(fmt, arg...) do {} while (0)
94 #endif
95 #ifdef DEBUG_PROTO_E
96 #define TRACE_PE(format, args...) printk("r3964: " format "\n" , ## args)
97 #else
98 #define TRACE_PE(fmt, arg...) do {} while (0)
99 #endif
100 #ifdef DEBUG_LDISC
101 #define TRACE_L(format, args...) printk("r3964: " format "\n" , ## args)
102 #else
103 #define TRACE_L(fmt, arg...) do {} while (0)
104 #endif
105 #ifdef DEBUG_QUEUE
106 #define TRACE_Q(format, args...) printk("r3964: " format "\n" , ## args)
107 #else
108 #define TRACE_Q(fmt, arg...) do {} while (0)
109 #endif
110 static void add_tx_queue(struct r3964_info *, struct r3964_block_header *);
111 static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code);
112 static void put_char(struct r3964_info *pInfo, unsigned char ch);
113 static void trigger_transmit(struct r3964_info *pInfo);
114 static void retry_transmit(struct r3964_info *pInfo);
115 static void transmit_block(struct r3964_info *pInfo);
116 static void receive_char(struct r3964_info *pInfo, const unsigned char c);
117 static void receive_error(struct r3964_info *pInfo, const char flag);
118 static void on_timeout(struct timer_list *t);
119 static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg);
120 static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
121 unsigned char __user * buf);
122 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
123 int error_code, struct r3964_block_header *pBlock);
124 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
125 struct r3964_client_info *pClient);
126 static void remove_client_block(struct r3964_info *pInfo,
127 struct r3964_client_info *pClient);
128
129 static int r3964_open(struct tty_struct *tty);
130 static void r3964_close(struct tty_struct *tty);
131 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
132 unsigned char __user * buf, size_t nr);
133 static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
134 const unsigned char *buf, size_t nr);
135 static int r3964_ioctl(struct tty_struct *tty, struct file *file,
136 unsigned int cmd, unsigned long arg);
137 #ifdef CONFIG_COMPAT
138 static int r3964_compat_ioctl(struct tty_struct *tty, struct file *file,
139 unsigned int cmd, unsigned long arg);
140 #endif
141 static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old);
142 static __poll_t r3964_poll(struct tty_struct *tty, struct file *file,
143 struct poll_table_struct *wait);
144 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
145 char *fp, int count);
146
147 static struct tty_ldisc_ops tty_ldisc_N_R3964 = {
148 .owner = THIS_MODULE,
149 .magic = TTY_LDISC_MAGIC,
150 .name = "R3964",
151 .open = r3964_open,
152 .close = r3964_close,
153 .read = r3964_read,
154 .write = r3964_write,
155 .ioctl = r3964_ioctl,
156 #ifdef CONFIG_COMPAT
157 .compat_ioctl = r3964_compat_ioctl,
158 #endif
159 .set_termios = r3964_set_termios,
160 .poll = r3964_poll,
161 .receive_buf = r3964_receive_buf,
162 };
163
dump_block(const unsigned char * block,unsigned int length)164 static void dump_block(const unsigned char *block, unsigned int length)
165 {
166 unsigned int i, j;
167 char linebuf[16 * 3 + 1];
168
169 for (i = 0; i < length; i += 16) {
170 for (j = 0; (j < 16) && (j + i < length); j++) {
171 sprintf(linebuf + 3 * j, "%02x ", block[i + j]);
172 }
173 linebuf[3 * j] = '\0';
174 TRACE_PS("%s", linebuf);
175 }
176 }
177
178 /*************************************************************
179 * Driver initialisation
180 *************************************************************/
181
182 /*************************************************************
183 * Module support routines
184 *************************************************************/
185
r3964_exit(void)186 static void __exit r3964_exit(void)
187 {
188 int status;
189
190 TRACE_M("cleanup_module()");
191
192 status = tty_unregister_ldisc(N_R3964);
193
194 if (status != 0) {
195 printk(KERN_ERR "r3964: error unregistering linediscipline: "
196 "%d\n", status);
197 } else {
198 TRACE_L("linediscipline successfully unregistered");
199 }
200 }
201
r3964_init(void)202 static int __init r3964_init(void)
203 {
204 int status;
205
206 printk("r3964: Philips r3964 Driver $Revision: 1.10 $\n");
207
208 /*
209 * Register the tty line discipline
210 */
211
212 status = tty_register_ldisc(N_R3964, &tty_ldisc_N_R3964);
213 if (status == 0) {
214 TRACE_L("line discipline %d registered", N_R3964);
215 TRACE_L("flags=%x num=%x", tty_ldisc_N_R3964.flags,
216 tty_ldisc_N_R3964.num);
217 TRACE_L("open=%p", tty_ldisc_N_R3964.open);
218 TRACE_L("tty_ldisc_N_R3964 = %p", &tty_ldisc_N_R3964);
219 } else {
220 printk(KERN_ERR "r3964: error registering line discipline: "
221 "%d\n", status);
222 }
223 return status;
224 }
225
226 module_init(r3964_init);
227 module_exit(r3964_exit);
228
229 /*************************************************************
230 * Protocol implementation routines
231 *************************************************************/
232
add_tx_queue(struct r3964_info * pInfo,struct r3964_block_header * pHeader)233 static void add_tx_queue(struct r3964_info *pInfo,
234 struct r3964_block_header *pHeader)
235 {
236 unsigned long flags;
237
238 spin_lock_irqsave(&pInfo->lock, flags);
239
240 pHeader->next = NULL;
241
242 if (pInfo->tx_last == NULL) {
243 pInfo->tx_first = pInfo->tx_last = pHeader;
244 } else {
245 pInfo->tx_last->next = pHeader;
246 pInfo->tx_last = pHeader;
247 }
248
249 spin_unlock_irqrestore(&pInfo->lock, flags);
250
251 TRACE_Q("add_tx_queue %p, length %d, tx_first = %p",
252 pHeader, pHeader->length, pInfo->tx_first);
253 }
254
remove_from_tx_queue(struct r3964_info * pInfo,int error_code)255 static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code)
256 {
257 struct r3964_block_header *pHeader;
258 unsigned long flags;
259 #ifdef DEBUG_QUEUE
260 struct r3964_block_header *pDump;
261 #endif
262
263 pHeader = pInfo->tx_first;
264
265 if (pHeader == NULL)
266 return;
267
268 #ifdef DEBUG_QUEUE
269 printk("r3964: remove_from_tx_queue: %p, length %u - ",
270 pHeader, pHeader->length);
271 for (pDump = pHeader; pDump; pDump = pDump->next)
272 printk("%p ", pDump);
273 printk("\n");
274 #endif
275
276 if (pHeader->owner) {
277 if (error_code) {
278 add_msg(pHeader->owner, R3964_MSG_ACK, 0,
279 error_code, NULL);
280 } else {
281 add_msg(pHeader->owner, R3964_MSG_ACK, pHeader->length,
282 error_code, NULL);
283 }
284 wake_up_interruptible(&pInfo->tty->read_wait);
285 }
286
287 spin_lock_irqsave(&pInfo->lock, flags);
288
289 pInfo->tx_first = pHeader->next;
290 if (pInfo->tx_first == NULL) {
291 pInfo->tx_last = NULL;
292 }
293
294 spin_unlock_irqrestore(&pInfo->lock, flags);
295
296 kfree(pHeader);
297 TRACE_M("remove_from_tx_queue - kfree %p", pHeader);
298
299 TRACE_Q("remove_from_tx_queue: tx_first = %p, tx_last = %p",
300 pInfo->tx_first, pInfo->tx_last);
301 }
302
add_rx_queue(struct r3964_info * pInfo,struct r3964_block_header * pHeader)303 static void add_rx_queue(struct r3964_info *pInfo,
304 struct r3964_block_header *pHeader)
305 {
306 unsigned long flags;
307
308 spin_lock_irqsave(&pInfo->lock, flags);
309
310 pHeader->next = NULL;
311
312 if (pInfo->rx_last == NULL) {
313 pInfo->rx_first = pInfo->rx_last = pHeader;
314 } else {
315 pInfo->rx_last->next = pHeader;
316 pInfo->rx_last = pHeader;
317 }
318 pInfo->blocks_in_rx_queue++;
319
320 spin_unlock_irqrestore(&pInfo->lock, flags);
321
322 TRACE_Q("add_rx_queue: %p, length = %d, rx_first = %p, count = %d",
323 pHeader, pHeader->length,
324 pInfo->rx_first, pInfo->blocks_in_rx_queue);
325 }
326
remove_from_rx_queue(struct r3964_info * pInfo,struct r3964_block_header * pHeader)327 static void remove_from_rx_queue(struct r3964_info *pInfo,
328 struct r3964_block_header *pHeader)
329 {
330 unsigned long flags;
331 struct r3964_block_header *pFind;
332
333 if (pHeader == NULL)
334 return;
335
336 TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
337 pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
338 TRACE_Q("remove_from_rx_queue: %p, length %u",
339 pHeader, pHeader->length);
340
341 spin_lock_irqsave(&pInfo->lock, flags);
342
343 if (pInfo->rx_first == pHeader) {
344 /* Remove the first block in the linked list: */
345 pInfo->rx_first = pHeader->next;
346
347 if (pInfo->rx_first == NULL) {
348 pInfo->rx_last = NULL;
349 }
350 pInfo->blocks_in_rx_queue--;
351 } else {
352 /* Find block to remove: */
353 for (pFind = pInfo->rx_first; pFind; pFind = pFind->next) {
354 if (pFind->next == pHeader) {
355 /* Got it. */
356 pFind->next = pHeader->next;
357 pInfo->blocks_in_rx_queue--;
358 if (pFind->next == NULL) {
359 /* Oh, removed the last one! */
360 pInfo->rx_last = pFind;
361 }
362 break;
363 }
364 }
365 }
366
367 spin_unlock_irqrestore(&pInfo->lock, flags);
368
369 kfree(pHeader);
370 TRACE_M("remove_from_rx_queue - kfree %p", pHeader);
371
372 TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
373 pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
374 }
375
put_char(struct r3964_info * pInfo,unsigned char ch)376 static void put_char(struct r3964_info *pInfo, unsigned char ch)
377 {
378 struct tty_struct *tty = pInfo->tty;
379 /* FIXME: put_char should not be called from an IRQ */
380 tty_put_char(tty, ch);
381 pInfo->bcc ^= ch;
382 }
383
flush(struct r3964_info * pInfo)384 static void flush(struct r3964_info *pInfo)
385 {
386 struct tty_struct *tty = pInfo->tty;
387
388 if (tty == NULL || tty->ops->flush_chars == NULL)
389 return;
390 tty->ops->flush_chars(tty);
391 }
392
trigger_transmit(struct r3964_info * pInfo)393 static void trigger_transmit(struct r3964_info *pInfo)
394 {
395 unsigned long flags;
396
397 spin_lock_irqsave(&pInfo->lock, flags);
398
399 if ((pInfo->state == R3964_IDLE) && (pInfo->tx_first != NULL)) {
400 pInfo->state = R3964_TX_REQUEST;
401 pInfo->nRetry = 0;
402 pInfo->flags &= ~R3964_ERROR;
403 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
404
405 spin_unlock_irqrestore(&pInfo->lock, flags);
406
407 TRACE_PS("trigger_transmit - sent STX");
408
409 put_char(pInfo, STX);
410 flush(pInfo);
411
412 pInfo->bcc = 0;
413 } else {
414 spin_unlock_irqrestore(&pInfo->lock, flags);
415 }
416 }
417
retry_transmit(struct r3964_info * pInfo)418 static void retry_transmit(struct r3964_info *pInfo)
419 {
420 if (pInfo->nRetry < R3964_MAX_RETRIES) {
421 TRACE_PE("transmission failed. Retry #%d", pInfo->nRetry);
422 pInfo->bcc = 0;
423 put_char(pInfo, STX);
424 flush(pInfo);
425 pInfo->state = R3964_TX_REQUEST;
426 pInfo->nRetry++;
427 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
428 } else {
429 TRACE_PE("transmission failed after %d retries",
430 R3964_MAX_RETRIES);
431
432 remove_from_tx_queue(pInfo, R3964_TX_FAIL);
433
434 put_char(pInfo, NAK);
435 flush(pInfo);
436 pInfo->state = R3964_IDLE;
437
438 trigger_transmit(pInfo);
439 }
440 }
441
transmit_block(struct r3964_info * pInfo)442 static void transmit_block(struct r3964_info *pInfo)
443 {
444 struct tty_struct *tty = pInfo->tty;
445 struct r3964_block_header *pBlock = pInfo->tx_first;
446 int room = 0;
447
448 if (tty == NULL || pBlock == NULL) {
449 return;
450 }
451
452 room = tty_write_room(tty);
453
454 TRACE_PS("transmit_block %p, room %d, length %d",
455 pBlock, room, pBlock->length);
456
457 while (pInfo->tx_position < pBlock->length) {
458 if (room < 2)
459 break;
460
461 if (pBlock->data[pInfo->tx_position] == DLE) {
462 /* send additional DLE char: */
463 put_char(pInfo, DLE);
464 }
465 put_char(pInfo, pBlock->data[pInfo->tx_position++]);
466
467 room--;
468 }
469
470 if ((pInfo->tx_position == pBlock->length) && (room >= 3)) {
471 put_char(pInfo, DLE);
472 put_char(pInfo, ETX);
473 if (pInfo->flags & R3964_BCC) {
474 put_char(pInfo, pInfo->bcc);
475 }
476 pInfo->state = R3964_WAIT_FOR_TX_ACK;
477 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
478 }
479 flush(pInfo);
480 }
481
on_receive_block(struct r3964_info * pInfo)482 static void on_receive_block(struct r3964_info *pInfo)
483 {
484 unsigned int length;
485 struct r3964_client_info *pClient;
486 struct r3964_block_header *pBlock;
487
488 length = pInfo->rx_position;
489
490 /* compare byte checksum characters: */
491 if (pInfo->flags & R3964_BCC) {
492 if (pInfo->bcc != pInfo->last_rx) {
493 TRACE_PE("checksum error - got %x but expected %x",
494 pInfo->last_rx, pInfo->bcc);
495 pInfo->flags |= R3964_CHECKSUM;
496 }
497 }
498
499 /* check for errors (parity, overrun,...): */
500 if (pInfo->flags & R3964_ERROR) {
501 TRACE_PE("on_receive_block - transmission failed error %x",
502 pInfo->flags & R3964_ERROR);
503
504 put_char(pInfo, NAK);
505 flush(pInfo);
506 if (pInfo->nRetry < R3964_MAX_RETRIES) {
507 pInfo->state = R3964_WAIT_FOR_RX_REPEAT;
508 pInfo->nRetry++;
509 mod_timer(&pInfo->tmr, jiffies + R3964_TO_RX_PANIC);
510 } else {
511 TRACE_PE("on_receive_block - failed after max retries");
512 pInfo->state = R3964_IDLE;
513 }
514 return;
515 }
516
517 /* received block; submit DLE: */
518 put_char(pInfo, DLE);
519 flush(pInfo);
520 del_timer_sync(&pInfo->tmr);
521 TRACE_PS(" rx success: got %d chars", length);
522
523 /* prepare struct r3964_block_header: */
524 pBlock = kmalloc(length + sizeof(struct r3964_block_header),
525 GFP_KERNEL);
526 TRACE_M("on_receive_block - kmalloc %p", pBlock);
527
528 if (pBlock == NULL)
529 return;
530
531 pBlock->length = length;
532 pBlock->data = ((unsigned char *)pBlock) +
533 sizeof(struct r3964_block_header);
534 pBlock->locks = 0;
535 pBlock->next = NULL;
536 pBlock->owner = NULL;
537
538 memcpy(pBlock->data, pInfo->rx_buf, length);
539
540 /* queue block into rx_queue: */
541 add_rx_queue(pInfo, pBlock);
542
543 /* notify attached client processes: */
544 for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
545 if (pClient->sig_flags & R3964_SIG_DATA) {
546 add_msg(pClient, R3964_MSG_DATA, length, R3964_OK,
547 pBlock);
548 }
549 }
550 wake_up_interruptible(&pInfo->tty->read_wait);
551
552 pInfo->state = R3964_IDLE;
553
554 trigger_transmit(pInfo);
555 }
556
receive_char(struct r3964_info * pInfo,const unsigned char c)557 static void receive_char(struct r3964_info *pInfo, const unsigned char c)
558 {
559 switch (pInfo->state) {
560 case R3964_TX_REQUEST:
561 if (c == DLE) {
562 TRACE_PS("TX_REQUEST - got DLE");
563
564 pInfo->state = R3964_TRANSMITTING;
565 pInfo->tx_position = 0;
566
567 transmit_block(pInfo);
568 } else if (c == STX) {
569 if (pInfo->nRetry == 0) {
570 TRACE_PE("TX_REQUEST - init conflict");
571 if (pInfo->priority == R3964_SLAVE) {
572 goto start_receiving;
573 }
574 } else {
575 TRACE_PE("TX_REQUEST - secondary init "
576 "conflict!? Switching to SLAVE mode "
577 "for next rx.");
578 goto start_receiving;
579 }
580 } else {
581 TRACE_PE("TX_REQUEST - char != DLE: %x", c);
582 retry_transmit(pInfo);
583 }
584 break;
585 case R3964_TRANSMITTING:
586 if (c == NAK) {
587 TRACE_PE("TRANSMITTING - got NAK");
588 retry_transmit(pInfo);
589 } else {
590 TRACE_PE("TRANSMITTING - got invalid char");
591
592 pInfo->state = R3964_WAIT_ZVZ_BEFORE_TX_RETRY;
593 mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
594 }
595 break;
596 case R3964_WAIT_FOR_TX_ACK:
597 if (c == DLE) {
598 TRACE_PS("WAIT_FOR_TX_ACK - got DLE");
599 remove_from_tx_queue(pInfo, R3964_OK);
600
601 pInfo->state = R3964_IDLE;
602 trigger_transmit(pInfo);
603 } else {
604 retry_transmit(pInfo);
605 }
606 break;
607 case R3964_WAIT_FOR_RX_REPEAT:
608 case R3964_IDLE:
609 if (c == STX) {
610 /* Prevent rx_queue from overflow: */
611 if (pInfo->blocks_in_rx_queue >=
612 R3964_MAX_BLOCKS_IN_RX_QUEUE) {
613 TRACE_PE("IDLE - got STX but no space in "
614 "rx_queue!");
615 pInfo->state = R3964_WAIT_FOR_RX_BUF;
616 mod_timer(&pInfo->tmr,
617 jiffies + R3964_TO_NO_BUF);
618 break;
619 }
620 start_receiving:
621 /* Ok, start receiving: */
622 TRACE_PS("IDLE - got STX");
623 pInfo->rx_position = 0;
624 pInfo->last_rx = 0;
625 pInfo->flags &= ~R3964_ERROR;
626 pInfo->state = R3964_RECEIVING;
627 mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
628 pInfo->nRetry = 0;
629 put_char(pInfo, DLE);
630 flush(pInfo);
631 pInfo->bcc = 0;
632 }
633 break;
634 case R3964_RECEIVING:
635 if (pInfo->rx_position < RX_BUF_SIZE) {
636 pInfo->bcc ^= c;
637
638 if (c == DLE) {
639 if (pInfo->last_rx == DLE) {
640 pInfo->last_rx = 0;
641 goto char_to_buf;
642 }
643 pInfo->last_rx = DLE;
644 break;
645 } else if ((c == ETX) && (pInfo->last_rx == DLE)) {
646 if (pInfo->flags & R3964_BCC) {
647 pInfo->state = R3964_WAIT_FOR_BCC;
648 mod_timer(&pInfo->tmr,
649 jiffies + R3964_TO_ZVZ);
650 } else {
651 on_receive_block(pInfo);
652 }
653 } else {
654 pInfo->last_rx = c;
655 char_to_buf:
656 pInfo->rx_buf[pInfo->rx_position++] = c;
657 mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
658 }
659 }
660 /* else: overflow-msg? BUF_SIZE>MTU; should not happen? */
661 break;
662 case R3964_WAIT_FOR_BCC:
663 pInfo->last_rx = c;
664 on_receive_block(pInfo);
665 break;
666 }
667 }
668
receive_error(struct r3964_info * pInfo,const char flag)669 static void receive_error(struct r3964_info *pInfo, const char flag)
670 {
671 switch (flag) {
672 case TTY_NORMAL:
673 break;
674 case TTY_BREAK:
675 TRACE_PE("received break");
676 pInfo->flags |= R3964_BREAK;
677 break;
678 case TTY_PARITY:
679 TRACE_PE("parity error");
680 pInfo->flags |= R3964_PARITY;
681 break;
682 case TTY_FRAME:
683 TRACE_PE("frame error");
684 pInfo->flags |= R3964_FRAME;
685 break;
686 case TTY_OVERRUN:
687 TRACE_PE("frame overrun");
688 pInfo->flags |= R3964_OVERRUN;
689 break;
690 default:
691 TRACE_PE("receive_error - unknown flag %d", flag);
692 pInfo->flags |= R3964_UNKNOWN;
693 break;
694 }
695 }
696
on_timeout(struct timer_list * t)697 static void on_timeout(struct timer_list *t)
698 {
699 struct r3964_info *pInfo = from_timer(pInfo, t, tmr);
700
701 switch (pInfo->state) {
702 case R3964_TX_REQUEST:
703 TRACE_PE("TX_REQUEST - timeout");
704 retry_transmit(pInfo);
705 break;
706 case R3964_WAIT_ZVZ_BEFORE_TX_RETRY:
707 put_char(pInfo, NAK);
708 flush(pInfo);
709 retry_transmit(pInfo);
710 break;
711 case R3964_WAIT_FOR_TX_ACK:
712 TRACE_PE("WAIT_FOR_TX_ACK - timeout");
713 retry_transmit(pInfo);
714 break;
715 case R3964_WAIT_FOR_RX_BUF:
716 TRACE_PE("WAIT_FOR_RX_BUF - timeout");
717 put_char(pInfo, NAK);
718 flush(pInfo);
719 pInfo->state = R3964_IDLE;
720 break;
721 case R3964_RECEIVING:
722 TRACE_PE("RECEIVING - timeout after %d chars",
723 pInfo->rx_position);
724 put_char(pInfo, NAK);
725 flush(pInfo);
726 pInfo->state = R3964_IDLE;
727 break;
728 case R3964_WAIT_FOR_RX_REPEAT:
729 TRACE_PE("WAIT_FOR_RX_REPEAT - timeout");
730 pInfo->state = R3964_IDLE;
731 break;
732 case R3964_WAIT_FOR_BCC:
733 TRACE_PE("WAIT_FOR_BCC - timeout");
734 put_char(pInfo, NAK);
735 flush(pInfo);
736 pInfo->state = R3964_IDLE;
737 break;
738 }
739 }
740
findClient(struct r3964_info * pInfo,struct pid * pid)741 static struct r3964_client_info *findClient(struct r3964_info *pInfo,
742 struct pid *pid)
743 {
744 struct r3964_client_info *pClient;
745
746 for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
747 if (pClient->pid == pid) {
748 return pClient;
749 }
750 }
751 return NULL;
752 }
753
enable_signals(struct r3964_info * pInfo,struct pid * pid,int arg)754 static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg)
755 {
756 struct r3964_client_info *pClient;
757 struct r3964_client_info **ppClient;
758 struct r3964_message *pMsg;
759
760 if ((arg & R3964_SIG_ALL) == 0) {
761 /* Remove client from client list */
762 for (ppClient = &pInfo->firstClient; *ppClient;
763 ppClient = &(*ppClient)->next) {
764 pClient = *ppClient;
765
766 if (pClient->pid == pid) {
767 TRACE_PS("removing client %d from client list",
768 pid_nr(pid));
769 *ppClient = pClient->next;
770 while (pClient->msg_count) {
771 pMsg = remove_msg(pInfo, pClient);
772 if (pMsg) {
773 kfree(pMsg);
774 TRACE_M("enable_signals - msg "
775 "kfree %p", pMsg);
776 }
777 }
778 put_pid(pClient->pid);
779 kfree(pClient);
780 TRACE_M("enable_signals - kfree %p", pClient);
781 return 0;
782 }
783 }
784 return -EINVAL;
785 } else {
786 pClient = findClient(pInfo, pid);
787 if (pClient) {
788 /* update signal options */
789 pClient->sig_flags = arg;
790 } else {
791 /* add client to client list */
792 pClient = kmalloc(sizeof(struct r3964_client_info),
793 GFP_KERNEL);
794 TRACE_M("enable_signals - kmalloc %p", pClient);
795 if (pClient == NULL)
796 return -ENOMEM;
797
798 TRACE_PS("add client %d to client list", pid_nr(pid));
799 spin_lock_init(&pClient->lock);
800 pClient->sig_flags = arg;
801 pClient->pid = get_pid(pid);
802 pClient->next = pInfo->firstClient;
803 pClient->first_msg = NULL;
804 pClient->last_msg = NULL;
805 pClient->next_block_to_read = NULL;
806 pClient->msg_count = 0;
807 pInfo->firstClient = pClient;
808 }
809 }
810
811 return 0;
812 }
813
read_telegram(struct r3964_info * pInfo,struct pid * pid,unsigned char __user * buf)814 static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
815 unsigned char __user * buf)
816 {
817 struct r3964_client_info *pClient;
818 struct r3964_block_header *block;
819
820 if (!buf) {
821 return -EINVAL;
822 }
823
824 pClient = findClient(pInfo, pid);
825 if (pClient == NULL) {
826 return -EINVAL;
827 }
828
829 block = pClient->next_block_to_read;
830 if (!block) {
831 return 0;
832 } else {
833 if (copy_to_user(buf, block->data, block->length))
834 return -EFAULT;
835
836 remove_client_block(pInfo, pClient);
837 return block->length;
838 }
839
840 return -EINVAL;
841 }
842
add_msg(struct r3964_client_info * pClient,int msg_id,int arg,int error_code,struct r3964_block_header * pBlock)843 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
844 int error_code, struct r3964_block_header *pBlock)
845 {
846 struct r3964_message *pMsg;
847 unsigned long flags;
848
849 if (pClient->msg_count < R3964_MAX_MSG_COUNT - 1) {
850 queue_the_message:
851
852 pMsg = kmalloc(sizeof(struct r3964_message),
853 error_code ? GFP_ATOMIC : GFP_KERNEL);
854 TRACE_M("add_msg - kmalloc %p", pMsg);
855 if (pMsg == NULL) {
856 return;
857 }
858
859 spin_lock_irqsave(&pClient->lock, flags);
860
861 pMsg->msg_id = msg_id;
862 pMsg->arg = arg;
863 pMsg->error_code = error_code;
864 pMsg->block = pBlock;
865 pMsg->next = NULL;
866
867 if (pClient->last_msg == NULL) {
868 pClient->first_msg = pClient->last_msg = pMsg;
869 } else {
870 pClient->last_msg->next = pMsg;
871 pClient->last_msg = pMsg;
872 }
873
874 pClient->msg_count++;
875
876 if (pBlock != NULL) {
877 pBlock->locks++;
878 }
879 spin_unlock_irqrestore(&pClient->lock, flags);
880 } else {
881 if ((pClient->last_msg->msg_id == R3964_MSG_ACK)
882 && (pClient->last_msg->error_code == R3964_OVERFLOW)) {
883 pClient->last_msg->arg++;
884 TRACE_PE("add_msg - inc prev OVERFLOW-msg");
885 } else {
886 msg_id = R3964_MSG_ACK;
887 arg = 0;
888 error_code = R3964_OVERFLOW;
889 pBlock = NULL;
890 TRACE_PE("add_msg - queue OVERFLOW-msg");
891 goto queue_the_message;
892 }
893 }
894 /* Send SIGIO signal to client process: */
895 if (pClient->sig_flags & R3964_USE_SIGIO) {
896 kill_pid(pClient->pid, SIGIO, 1);
897 }
898 }
899
remove_msg(struct r3964_info * pInfo,struct r3964_client_info * pClient)900 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
901 struct r3964_client_info *pClient)
902 {
903 struct r3964_message *pMsg = NULL;
904 unsigned long flags;
905
906 if (pClient->first_msg) {
907 spin_lock_irqsave(&pClient->lock, flags);
908
909 pMsg = pClient->first_msg;
910 pClient->first_msg = pMsg->next;
911 if (pClient->first_msg == NULL) {
912 pClient->last_msg = NULL;
913 }
914
915 pClient->msg_count--;
916 if (pMsg->block) {
917 remove_client_block(pInfo, pClient);
918 pClient->next_block_to_read = pMsg->block;
919 }
920 spin_unlock_irqrestore(&pClient->lock, flags);
921 }
922 return pMsg;
923 }
924
remove_client_block(struct r3964_info * pInfo,struct r3964_client_info * pClient)925 static void remove_client_block(struct r3964_info *pInfo,
926 struct r3964_client_info *pClient)
927 {
928 struct r3964_block_header *block;
929
930 TRACE_PS("remove_client_block PID %d", pid_nr(pClient->pid));
931
932 block = pClient->next_block_to_read;
933 if (block) {
934 block->locks--;
935 if (block->locks == 0) {
936 remove_from_rx_queue(pInfo, block);
937 }
938 }
939 pClient->next_block_to_read = NULL;
940 }
941
942 /*************************************************************
943 * Line discipline routines
944 *************************************************************/
945
r3964_open(struct tty_struct * tty)946 static int r3964_open(struct tty_struct *tty)
947 {
948 struct r3964_info *pInfo;
949
950 TRACE_L("open");
951 TRACE_L("tty=%p, PID=%d, disc_data=%p",
952 tty, current->pid, tty->disc_data);
953
954 pInfo = kmalloc(sizeof(struct r3964_info), GFP_KERNEL);
955 TRACE_M("r3964_open - info kmalloc %p", pInfo);
956
957 if (!pInfo) {
958 printk(KERN_ERR "r3964: failed to alloc info structure\n");
959 return -ENOMEM;
960 }
961
962 pInfo->rx_buf = kmalloc(RX_BUF_SIZE, GFP_KERNEL);
963 TRACE_M("r3964_open - rx_buf kmalloc %p", pInfo->rx_buf);
964
965 if (!pInfo->rx_buf) {
966 printk(KERN_ERR "r3964: failed to alloc receive buffer\n");
967 kfree(pInfo);
968 TRACE_M("r3964_open - info kfree %p", pInfo);
969 return -ENOMEM;
970 }
971
972 pInfo->tx_buf = kmalloc(TX_BUF_SIZE, GFP_KERNEL);
973 TRACE_M("r3964_open - tx_buf kmalloc %p", pInfo->tx_buf);
974
975 if (!pInfo->tx_buf) {
976 printk(KERN_ERR "r3964: failed to alloc transmit buffer\n");
977 kfree(pInfo->rx_buf);
978 TRACE_M("r3964_open - rx_buf kfree %p", pInfo->rx_buf);
979 kfree(pInfo);
980 TRACE_M("r3964_open - info kfree %p", pInfo);
981 return -ENOMEM;
982 }
983
984 spin_lock_init(&pInfo->lock);
985 mutex_init(&pInfo->read_lock);
986 pInfo->tty = tty;
987 pInfo->priority = R3964_MASTER;
988 pInfo->rx_first = pInfo->rx_last = NULL;
989 pInfo->tx_first = pInfo->tx_last = NULL;
990 pInfo->rx_position = 0;
991 pInfo->tx_position = 0;
992 pInfo->last_rx = 0;
993 pInfo->blocks_in_rx_queue = 0;
994 pInfo->firstClient = NULL;
995 pInfo->state = R3964_IDLE;
996 pInfo->flags = R3964_DEBUG;
997 pInfo->nRetry = 0;
998
999 tty->disc_data = pInfo;
1000 tty->receive_room = 65536;
1001
1002 timer_setup(&pInfo->tmr, on_timeout, 0);
1003
1004 return 0;
1005 }
1006
r3964_close(struct tty_struct * tty)1007 static void r3964_close(struct tty_struct *tty)
1008 {
1009 struct r3964_info *pInfo = tty->disc_data;
1010 struct r3964_client_info *pClient, *pNext;
1011 struct r3964_message *pMsg;
1012 struct r3964_block_header *pHeader, *pNextHeader;
1013 unsigned long flags;
1014
1015 TRACE_L("close");
1016
1017 /*
1018 * Make sure that our task queue isn't activated. If it
1019 * is, take it out of the linked list.
1020 */
1021 del_timer_sync(&pInfo->tmr);
1022
1023 /* Remove client-structs and message queues: */
1024 pClient = pInfo->firstClient;
1025 while (pClient) {
1026 pNext = pClient->next;
1027 while (pClient->msg_count) {
1028 pMsg = remove_msg(pInfo, pClient);
1029 if (pMsg) {
1030 kfree(pMsg);
1031 TRACE_M("r3964_close - msg kfree %p", pMsg);
1032 }
1033 }
1034 put_pid(pClient->pid);
1035 kfree(pClient);
1036 TRACE_M("r3964_close - client kfree %p", pClient);
1037 pClient = pNext;
1038 }
1039 /* Remove jobs from tx_queue: */
1040 spin_lock_irqsave(&pInfo->lock, flags);
1041 pHeader = pInfo->tx_first;
1042 pInfo->tx_first = pInfo->tx_last = NULL;
1043 spin_unlock_irqrestore(&pInfo->lock, flags);
1044
1045 while (pHeader) {
1046 pNextHeader = pHeader->next;
1047 kfree(pHeader);
1048 pHeader = pNextHeader;
1049 }
1050
1051 /* Free buffers: */
1052 kfree(pInfo->rx_buf);
1053 TRACE_M("r3964_close - rx_buf kfree %p", pInfo->rx_buf);
1054 kfree(pInfo->tx_buf);
1055 TRACE_M("r3964_close - tx_buf kfree %p", pInfo->tx_buf);
1056 kfree(pInfo);
1057 TRACE_M("r3964_close - info kfree %p", pInfo);
1058 }
1059
r3964_read(struct tty_struct * tty,struct file * file,unsigned char __user * buf,size_t nr)1060 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
1061 unsigned char __user * buf, size_t nr)
1062 {
1063 struct r3964_info *pInfo = tty->disc_data;
1064 struct r3964_client_info *pClient;
1065 struct r3964_message *pMsg;
1066 struct r3964_client_message theMsg;
1067 int ret;
1068
1069 TRACE_L("read()");
1070
1071 /*
1072 * Internal serialization of reads.
1073 */
1074 if (file->f_flags & O_NONBLOCK) {
1075 if (!mutex_trylock(&pInfo->read_lock))
1076 return -EAGAIN;
1077 } else {
1078 if (mutex_lock_interruptible(&pInfo->read_lock))
1079 return -ERESTARTSYS;
1080 }
1081
1082 pClient = findClient(pInfo, task_pid(current));
1083 if (pClient) {
1084 pMsg = remove_msg(pInfo, pClient);
1085 if (pMsg == NULL) {
1086 /* no messages available. */
1087 if (tty_io_nonblock(tty, file)) {
1088 ret = -EAGAIN;
1089 goto unlock;
1090 }
1091 /* block until there is a message: */
1092 wait_event_interruptible(tty->read_wait,
1093 (pMsg = remove_msg(pInfo, pClient)));
1094 }
1095
1096 /* If we still haven't got a message, we must have been signalled */
1097
1098 if (!pMsg) {
1099 ret = -EINTR;
1100 goto unlock;
1101 }
1102
1103 /* deliver msg to client process: */
1104 theMsg.msg_id = pMsg->msg_id;
1105 theMsg.arg = pMsg->arg;
1106 theMsg.error_code = pMsg->error_code;
1107 ret = sizeof(struct r3964_client_message);
1108
1109 kfree(pMsg);
1110 TRACE_M("r3964_read - msg kfree %p", pMsg);
1111
1112 if (copy_to_user(buf, &theMsg, ret)) {
1113 ret = -EFAULT;
1114 goto unlock;
1115 }
1116
1117 TRACE_PS("read - return %d", ret);
1118 goto unlock;
1119 }
1120 ret = -EPERM;
1121 unlock:
1122 mutex_unlock(&pInfo->read_lock);
1123 return ret;
1124 }
1125
r3964_write(struct tty_struct * tty,struct file * file,const unsigned char * data,size_t count)1126 static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
1127 const unsigned char *data, size_t count)
1128 {
1129 struct r3964_info *pInfo = tty->disc_data;
1130 struct r3964_block_header *pHeader;
1131 struct r3964_client_info *pClient;
1132 unsigned char *new_data;
1133
1134 TRACE_L("write request, %d characters", count);
1135 /*
1136 * Verify the pointers
1137 */
1138
1139 if (!pInfo)
1140 return -EIO;
1141
1142 /*
1143 * Ensure that the caller does not wish to send too much.
1144 */
1145 if (count > R3964_MTU) {
1146 if (pInfo->flags & R3964_DEBUG) {
1147 TRACE_L(KERN_WARNING "r3964_write: truncating user "
1148 "packet from %u to mtu %d", count, R3964_MTU);
1149 }
1150 count = R3964_MTU;
1151 }
1152 /*
1153 * Allocate a buffer for the data and copy it from the buffer with header prepended
1154 */
1155 new_data = kmalloc(count + sizeof(struct r3964_block_header),
1156 GFP_KERNEL);
1157 TRACE_M("r3964_write - kmalloc %p", new_data);
1158 if (new_data == NULL) {
1159 if (pInfo->flags & R3964_DEBUG) {
1160 printk(KERN_ERR "r3964_write: no memory\n");
1161 }
1162 return -ENOSPC;
1163 }
1164
1165 pHeader = (struct r3964_block_header *)new_data;
1166 pHeader->data = new_data + sizeof(struct r3964_block_header);
1167 pHeader->length = count;
1168 pHeader->locks = 0;
1169 pHeader->owner = NULL;
1170
1171 pClient = findClient(pInfo, task_pid(current));
1172 if (pClient) {
1173 pHeader->owner = pClient;
1174 }
1175
1176 memcpy(pHeader->data, data, count); /* We already verified this */
1177
1178 if (pInfo->flags & R3964_DEBUG) {
1179 dump_block(pHeader->data, count);
1180 }
1181
1182 /*
1183 * Add buffer to transmit-queue:
1184 */
1185 add_tx_queue(pInfo, pHeader);
1186 trigger_transmit(pInfo);
1187
1188 return 0;
1189 }
1190
r3964_ioctl(struct tty_struct * tty,struct file * file,unsigned int cmd,unsigned long arg)1191 static int r3964_ioctl(struct tty_struct *tty, struct file *file,
1192 unsigned int cmd, unsigned long arg)
1193 {
1194 struct r3964_info *pInfo = tty->disc_data;
1195 if (pInfo == NULL)
1196 return -EINVAL;
1197 switch (cmd) {
1198 case R3964_ENABLE_SIGNALS:
1199 return enable_signals(pInfo, task_pid(current), arg);
1200 case R3964_SETPRIORITY:
1201 if (arg < R3964_MASTER || arg > R3964_SLAVE)
1202 return -EINVAL;
1203 pInfo->priority = arg & 0xff;
1204 return 0;
1205 case R3964_USE_BCC:
1206 if (arg)
1207 pInfo->flags |= R3964_BCC;
1208 else
1209 pInfo->flags &= ~R3964_BCC;
1210 return 0;
1211 case R3964_READ_TELEGRAM:
1212 return read_telegram(pInfo, task_pid(current),
1213 (unsigned char __user *)arg);
1214 default:
1215 return -ENOIOCTLCMD;
1216 }
1217 }
1218
1219 #ifdef CONFIG_COMPAT
r3964_compat_ioctl(struct tty_struct * tty,struct file * file,unsigned int cmd,unsigned long arg)1220 static int r3964_compat_ioctl(struct tty_struct *tty, struct file *file,
1221 unsigned int cmd, unsigned long arg)
1222 {
1223 switch (cmd) {
1224 case R3964_ENABLE_SIGNALS:
1225 case R3964_SETPRIORITY:
1226 case R3964_USE_BCC:
1227 return r3964_ioctl(tty, file, cmd, arg);
1228 default:
1229 return -ENOIOCTLCMD;
1230 }
1231 }
1232 #endif
1233
r3964_set_termios(struct tty_struct * tty,struct ktermios * old)1234 static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old)
1235 {
1236 TRACE_L("set_termios");
1237 }
1238
1239 /* Called without the kernel lock held - fine */
r3964_poll(struct tty_struct * tty,struct file * file,struct poll_table_struct * wait)1240 static __poll_t r3964_poll(struct tty_struct *tty, struct file *file,
1241 struct poll_table_struct *wait)
1242 {
1243 struct r3964_info *pInfo = tty->disc_data;
1244 struct r3964_client_info *pClient;
1245 struct r3964_message *pMsg = NULL;
1246 unsigned long flags;
1247 __poll_t result = EPOLLOUT;
1248
1249 TRACE_L("POLL");
1250
1251 pClient = findClient(pInfo, task_pid(current));
1252 if (pClient) {
1253 poll_wait(file, &tty->read_wait, wait);
1254 spin_lock_irqsave(&pInfo->lock, flags);
1255 pMsg = pClient->first_msg;
1256 spin_unlock_irqrestore(&pInfo->lock, flags);
1257 if (pMsg)
1258 result |= EPOLLIN | EPOLLRDNORM;
1259 } else {
1260 result = -EINVAL;
1261 }
1262 return result;
1263 }
1264
r3964_receive_buf(struct tty_struct * tty,const unsigned char * cp,char * fp,int count)1265 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1266 char *fp, int count)
1267 {
1268 struct r3964_info *pInfo = tty->disc_data;
1269 const unsigned char *p;
1270 char *f, flags = TTY_NORMAL;
1271 int i;
1272
1273 for (i = count, p = cp, f = fp; i; i--, p++) {
1274 if (f)
1275 flags = *f++;
1276 if (flags == TTY_NORMAL) {
1277 receive_char(pInfo, *p);
1278 } else {
1279 receive_error(pInfo, flags);
1280 }
1281
1282 }
1283 }
1284
1285 MODULE_LICENSE("GPL");
1286 MODULE_ALIAS_LDISC(N_R3964);
1287
