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treewide: remove redundant IS_ERR() before error code check
[linux/fpc-iii.git] / drivers / tty / n_r3964.c
blobf75696f0ee2d03c83de6ee7af0ae93bd93440c4a
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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 /* FALLTHROUGH */
609 case R3964_IDLE:
610 if (c == STX) {
611 /* Prevent rx_queue from overflow: */
612 if (pInfo->blocks_in_rx_queue >=
613 R3964_MAX_BLOCKS_IN_RX_QUEUE) {
614 TRACE_PE("IDLE - got STX but no space in "
615 "rx_queue!");
616 pInfo->state = R3964_WAIT_FOR_RX_BUF;
617 mod_timer(&pInfo->tmr,
618 jiffies + R3964_TO_NO_BUF);
619 break;
620 }
621 start_receiving:
622 /* Ok, start receiving: */
623 TRACE_PS("IDLE - got STX");
624 pInfo->rx_position = 0;
625 pInfo->last_rx = 0;
626 pInfo->flags &= ~R3964_ERROR;
627 pInfo->state = R3964_RECEIVING;
628 mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
629 pInfo->nRetry = 0;
630 put_char(pInfo, DLE);
631 flush(pInfo);
632 pInfo->bcc = 0;
633 }
634 break;
635 case R3964_RECEIVING:
636 if (pInfo->rx_position < RX_BUF_SIZE) {
637 pInfo->bcc ^= c;
638
639 if (c == DLE) {
640 if (pInfo->last_rx == DLE) {
641 pInfo->last_rx = 0;
642 goto char_to_buf;
643 }
644 pInfo->last_rx = DLE;
645 break;
646 } else if ((c == ETX) && (pInfo->last_rx == DLE)) {
647 if (pInfo->flags & R3964_BCC) {
648 pInfo->state = R3964_WAIT_FOR_BCC;
649 mod_timer(&pInfo->tmr,
650 jiffies + R3964_TO_ZVZ);
651 } else {
652 on_receive_block(pInfo);
653 }
654 } else {
655 pInfo->last_rx = c;
656 char_to_buf:
657 pInfo->rx_buf[pInfo->rx_position++] = c;
658 mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
659 }
660 }
661 /* else: overflow-msg? BUF_SIZE>MTU; should not happen? */
662 break;
663 case R3964_WAIT_FOR_BCC:
664 pInfo->last_rx = c;
665 on_receive_block(pInfo);
666 break;
667 }
668 }
669
670 static void receive_error(struct r3964_info *pInfo, const char flag)
671 {
672 switch (flag) {
673 case TTY_NORMAL:
674 break;
675 case TTY_BREAK:
676 TRACE_PE("received break");
677 pInfo->flags |= R3964_BREAK;
678 break;
679 case TTY_PARITY:
680 TRACE_PE("parity error");
681 pInfo->flags |= R3964_PARITY;
682 break;
683 case TTY_FRAME:
684 TRACE_PE("frame error");
685 pInfo->flags |= R3964_FRAME;
686 break;
687 case TTY_OVERRUN:
688 TRACE_PE("frame overrun");
689 pInfo->flags |= R3964_OVERRUN;
690 break;
691 default:
692 TRACE_PE("receive_error - unknown flag %d", flag);
693 pInfo->flags |= R3964_UNKNOWN;
694 break;
695 }
696 }
697
698 static void on_timeout(struct timer_list *t)
699 {
700 struct r3964_info *pInfo = from_timer(pInfo, t, tmr);
701
702 switch (pInfo->state) {
703 case R3964_TX_REQUEST:
704 TRACE_PE("TX_REQUEST - timeout");
705 retry_transmit(pInfo);
706 break;
707 case R3964_WAIT_ZVZ_BEFORE_TX_RETRY:
708 put_char(pInfo, NAK);
709 flush(pInfo);
710 retry_transmit(pInfo);
711 break;
712 case R3964_WAIT_FOR_TX_ACK:
713 TRACE_PE("WAIT_FOR_TX_ACK - timeout");
714 retry_transmit(pInfo);
715 break;
716 case R3964_WAIT_FOR_RX_BUF:
717 TRACE_PE("WAIT_FOR_RX_BUF - timeout");
718 put_char(pInfo, NAK);
719 flush(pInfo);
720 pInfo->state = R3964_IDLE;
721 break;
722 case R3964_RECEIVING:
723 TRACE_PE("RECEIVING - timeout after %d chars",
724 pInfo->rx_position);
725 put_char(pInfo, NAK);
726 flush(pInfo);
727 pInfo->state = R3964_IDLE;
728 break;
729 case R3964_WAIT_FOR_RX_REPEAT:
730 TRACE_PE("WAIT_FOR_RX_REPEAT - timeout");
731 pInfo->state = R3964_IDLE;
732 break;
733 case R3964_WAIT_FOR_BCC:
734 TRACE_PE("WAIT_FOR_BCC - timeout");
735 put_char(pInfo, NAK);
736 flush(pInfo);
737 pInfo->state = R3964_IDLE;
738 break;
739 }
740 }
741
742 static struct r3964_client_info *findClient(struct r3964_info *pInfo,
743 struct pid *pid)
744 {
745 struct r3964_client_info *pClient;
746
747 for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
748 if (pClient->pid == pid) {
749 return pClient;
750 }
751 }
752 return NULL;
753 }
754
755 static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg)
756 {
757 struct r3964_client_info *pClient;
758 struct r3964_client_info **ppClient;
759 struct r3964_message *pMsg;
760
761 if ((arg & R3964_SIG_ALL) == 0) {
762 /* Remove client from client list */
763 for (ppClient = &pInfo->firstClient; *ppClient;
764 ppClient = &(*ppClient)->next) {
765 pClient = *ppClient;
766
767 if (pClient->pid == pid) {
768 TRACE_PS("removing client %d from client list",
769 pid_nr(pid));
770 *ppClient = pClient->next;
771 while (pClient->msg_count) {
772 pMsg = remove_msg(pInfo, pClient);
773 if (pMsg) {
774 kfree(pMsg);
775 TRACE_M("enable_signals - msg "
776 "kfree %p", pMsg);
777 }
778 }
779 put_pid(pClient->pid);
780 kfree(pClient);
781 TRACE_M("enable_signals - kfree %p", pClient);
782 return 0;
783 }
784 }
785 return -EINVAL;
786 } else {
787 pClient = findClient(pInfo, pid);
788 if (pClient) {
789 /* update signal options */
790 pClient->sig_flags = arg;
791 } else {
792 /* add client to client list */
793 pClient = kmalloc(sizeof(struct r3964_client_info),
794 GFP_KERNEL);
795 TRACE_M("enable_signals - kmalloc %p", pClient);
796 if (pClient == NULL)
797 return -ENOMEM;
798
799 TRACE_PS("add client %d to client list", pid_nr(pid));
800 spin_lock_init(&pClient->lock);
801 pClient->sig_flags = arg;
802 pClient->pid = get_pid(pid);
803 pClient->next = pInfo->firstClient;
804 pClient->first_msg = NULL;
805 pClient->last_msg = NULL;
806 pClient->next_block_to_read = NULL;
807 pClient->msg_count = 0;
808 pInfo->firstClient = pClient;
809 }
810 }
811
812 return 0;
813 }
814
815 static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
816 unsigned char __user * buf)
817 {
818 struct r3964_client_info *pClient;
819 struct r3964_block_header *block;
820
821 if (!buf) {
822 return -EINVAL;
823 }
824
825 pClient = findClient(pInfo, pid);
826 if (pClient == NULL) {
827 return -EINVAL;
828 }
829
830 block = pClient->next_block_to_read;
831 if (!block) {
832 return 0;
833 } else {
834 if (copy_to_user(buf, block->data, block->length))
835 return -EFAULT;
836
837 remove_client_block(pInfo, pClient);
838 return block->length;
839 }
840
841 return -EINVAL;
842 }
843
844 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
845 int error_code, struct r3964_block_header *pBlock)
846 {
847 struct r3964_message *pMsg;
848 unsigned long flags;
849
850 if (pClient->msg_count < R3964_MAX_MSG_COUNT - 1) {
851 queue_the_message:
852
853 pMsg = kmalloc(sizeof(struct r3964_message),
854 error_code ? GFP_ATOMIC : GFP_KERNEL);
855 TRACE_M("add_msg - kmalloc %p", pMsg);
856 if (pMsg == NULL) {
857 return;
858 }
859
860 spin_lock_irqsave(&pClient->lock, flags);
861
862 pMsg->msg_id = msg_id;
863 pMsg->arg = arg;
864 pMsg->error_code = error_code;
865 pMsg->block = pBlock;
866 pMsg->next = NULL;
867
868 if (pClient->last_msg == NULL) {
869 pClient->first_msg = pClient->last_msg = pMsg;
870 } else {
871 pClient->last_msg->next = pMsg;
872 pClient->last_msg = pMsg;
873 }
874
875 pClient->msg_count++;
876
877 if (pBlock != NULL) {
878 pBlock->locks++;
879 }
880 spin_unlock_irqrestore(&pClient->lock, flags);
881 } else {
882 if ((pClient->last_msg->msg_id == R3964_MSG_ACK)
883 && (pClient->last_msg->error_code == R3964_OVERFLOW)) {
884 pClient->last_msg->arg++;
885 TRACE_PE("add_msg - inc prev OVERFLOW-msg");
886 } else {
887 msg_id = R3964_MSG_ACK;
888 arg = 0;
889 error_code = R3964_OVERFLOW;
890 pBlock = NULL;
891 TRACE_PE("add_msg - queue OVERFLOW-msg");
892 goto queue_the_message;
893 }
894 }
895 /* Send SIGIO signal to client process: */
896 if (pClient->sig_flags & R3964_USE_SIGIO) {
897 kill_pid(pClient->pid, SIGIO, 1);
898 }
899 }
900
901 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
902 struct r3964_client_info *pClient)
903 {
904 struct r3964_message *pMsg = NULL;
905 unsigned long flags;
906
907 if (pClient->first_msg) {
908 spin_lock_irqsave(&pClient->lock, flags);
909
910 pMsg = pClient->first_msg;
911 pClient->first_msg = pMsg->next;
912 if (pClient->first_msg == NULL) {
913 pClient->last_msg = NULL;
914 }
915
916 pClient->msg_count--;
917 if (pMsg->block) {
918 remove_client_block(pInfo, pClient);
919 pClient->next_block_to_read = pMsg->block;
920 }
921 spin_unlock_irqrestore(&pClient->lock, flags);
922 }
923 return pMsg;
924 }
925
926 static void remove_client_block(struct r3964_info *pInfo,
927 struct r3964_client_info *pClient)
928 {
929 struct r3964_block_header *block;
930
931 TRACE_PS("remove_client_block PID %d", pid_nr(pClient->pid));
932
933 block = pClient->next_block_to_read;
934 if (block) {
935 block->locks--;
936 if (block->locks == 0) {
937 remove_from_rx_queue(pInfo, block);
938 }
939 }
940 pClient->next_block_to_read = NULL;
941 }
942
943 /*************************************************************
944 * Line discipline routines
945 *************************************************************/
946
947 static int r3964_open(struct tty_struct *tty)
948 {
949 struct r3964_info *pInfo;
950
951 TRACE_L("open");
952 TRACE_L("tty=%p, PID=%d, disc_data=%p",
953 tty, current->pid, tty->disc_data);
954
955 pInfo = kmalloc(sizeof(struct r3964_info), GFP_KERNEL);
956 TRACE_M("r3964_open - info kmalloc %p", pInfo);
957
958 if (!pInfo) {
959 printk(KERN_ERR "r3964: failed to alloc info structure\n");
960 return -ENOMEM;
961 }
962
963 pInfo->rx_buf = kmalloc(RX_BUF_SIZE, GFP_KERNEL);
964 TRACE_M("r3964_open - rx_buf kmalloc %p", pInfo->rx_buf);
965
966 if (!pInfo->rx_buf) {
967 printk(KERN_ERR "r3964: failed to alloc receive buffer\n");
968 kfree(pInfo);
969 TRACE_M("r3964_open - info kfree %p", pInfo);
970 return -ENOMEM;
971 }
972
973 pInfo->tx_buf = kmalloc(TX_BUF_SIZE, GFP_KERNEL);
974 TRACE_M("r3964_open - tx_buf kmalloc %p", pInfo->tx_buf);
975
976 if (!pInfo->tx_buf) {
977 printk(KERN_ERR "r3964: failed to alloc transmit buffer\n");
978 kfree(pInfo->rx_buf);
979 TRACE_M("r3964_open - rx_buf kfree %p", pInfo->rx_buf);
980 kfree(pInfo);
981 TRACE_M("r3964_open - info kfree %p", pInfo);
982 return -ENOMEM;
983 }
984
985 spin_lock_init(&pInfo->lock);
986 mutex_init(&pInfo->read_lock);
987 pInfo->tty = tty;
988 pInfo->priority = R3964_MASTER;
989 pInfo->rx_first = pInfo->rx_last = NULL;
990 pInfo->tx_first = pInfo->tx_last = NULL;
991 pInfo->rx_position = 0;
992 pInfo->tx_position = 0;
993 pInfo->last_rx = 0;
994 pInfo->blocks_in_rx_queue = 0;
995 pInfo->firstClient = NULL;
996 pInfo->state = R3964_IDLE;
997 pInfo->flags = R3964_DEBUG;
998 pInfo->nRetry = 0;
999
1000 tty->disc_data = pInfo;
1001 tty->receive_room = 65536;
1002
1003 timer_setup(&pInfo->tmr, on_timeout, 0);
1004
1005 return 0;
1006 }
1007
1008 static void r3964_close(struct tty_struct *tty)
1009 {
1010 struct r3964_info *pInfo = tty->disc_data;
1011 struct r3964_client_info *pClient, *pNext;
1012 struct r3964_message *pMsg;
1013 struct r3964_block_header *pHeader, *pNextHeader;
1014 unsigned long flags;
1015
1016 TRACE_L("close");
1017
1018 /*
1019 * Make sure that our task queue isn't activated. If it
1020 * is, take it out of the linked list.
1021 */
1022 del_timer_sync(&pInfo->tmr);
1023
1024 /* Remove client-structs and message queues: */
1025 pClient = pInfo->firstClient;
1026 while (pClient) {
1027 pNext = pClient->next;
1028 while (pClient->msg_count) {
1029 pMsg = remove_msg(pInfo, pClient);
1030 if (pMsg) {
1031 kfree(pMsg);
1032 TRACE_M("r3964_close - msg kfree %p", pMsg);
1033 }
1034 }
1035 put_pid(pClient->pid);
1036 kfree(pClient);
1037 TRACE_M("r3964_close - client kfree %p", pClient);
1038 pClient = pNext;
1039 }
1040 /* Remove jobs from tx_queue: */
1041 spin_lock_irqsave(&pInfo->lock, flags);
1042 pHeader = pInfo->tx_first;
1043 pInfo->tx_first = pInfo->tx_last = NULL;
1044 spin_unlock_irqrestore(&pInfo->lock, flags);
1045
1046 while (pHeader) {
1047 pNextHeader = pHeader->next;
1048 kfree(pHeader);
1049 pHeader = pNextHeader;
1050 }
1051
1052 /* Free buffers: */
1053 kfree(pInfo->rx_buf);
1054 TRACE_M("r3964_close - rx_buf kfree %p", pInfo->rx_buf);
1055 kfree(pInfo->tx_buf);
1056 TRACE_M("r3964_close - tx_buf kfree %p", pInfo->tx_buf);
1057 kfree(pInfo);
1058 TRACE_M("r3964_close - info kfree %p", pInfo);
1059 }
1060
1061 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
1062 unsigned char __user * buf, size_t nr)
1063 {
1064 struct r3964_info *pInfo = tty->disc_data;
1065 struct r3964_client_info *pClient;
1066 struct r3964_message *pMsg;
1067 struct r3964_client_message theMsg;
1068 int ret;
1069
1070 TRACE_L("read()");
1071
1072 /*
1073 * Internal serialization of reads.
1074 */
1075 if (file->f_flags & O_NONBLOCK) {
1076 if (!mutex_trylock(&pInfo->read_lock))
1077 return -EAGAIN;
1078 } else {
1079 if (mutex_lock_interruptible(&pInfo->read_lock))
1080 return -ERESTARTSYS;
1081 }
1082
1083 pClient = findClient(pInfo, task_pid(current));
1084 if (pClient) {
1085 pMsg = remove_msg(pInfo, pClient);
1086 if (pMsg == NULL) {
1087 /* no messages available. */
1088 if (tty_io_nonblock(tty, file)) {
1089 ret = -EAGAIN;
1090 goto unlock;
1091 }
1092 /* block until there is a message: */
1093 wait_event_interruptible(tty->read_wait,
1094 (pMsg = remove_msg(pInfo, pClient)));
1095 }
1096
1097 /* If we still haven't got a message, we must have been signalled */
1098
1099 if (!pMsg) {
1100 ret = -EINTR;
1101 goto unlock;
1102 }
1103
1104 /* deliver msg to client process: */
1105 theMsg.msg_id = pMsg->msg_id;
1106 theMsg.arg = pMsg->arg;
1107 theMsg.error_code = pMsg->error_code;
1108 ret = sizeof(struct r3964_client_message);
1109
1110 kfree(pMsg);
1111 TRACE_M("r3964_read - msg kfree %p", pMsg);
1112
1113 if (copy_to_user(buf, &theMsg, ret)) {
1114 ret = -EFAULT;
1115 goto unlock;
1116 }
1117
1118 TRACE_PS("read - return %d", ret);
1119 goto unlock;
1120 }
1121 ret = -EPERM;
1122 unlock:
1123 mutex_unlock(&pInfo->read_lock);
1124 return ret;
1125 }
1126
1127 static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
1128 const unsigned char *data, size_t count)
1129 {
1130 struct r3964_info *pInfo = tty->disc_data;
1131 struct r3964_block_header *pHeader;
1132 struct r3964_client_info *pClient;
1133 unsigned char *new_data;
1134
1135 TRACE_L("write request, %d characters", count);
1136 /*
1137 * Verify the pointers
1138 */
1139
1140 if (!pInfo)
1141 return -EIO;
1142
1143 /*
1144 * Ensure that the caller does not wish to send too much.
1145 */
1146 if (count > R3964_MTU) {
1147 if (pInfo->flags & R3964_DEBUG) {
1148 TRACE_L(KERN_WARNING "r3964_write: truncating user "
1149 "packet from %u to mtu %d", count, R3964_MTU);
1150 }
1151 count = R3964_MTU;
1152 }
1153 /*
1154 * Allocate a buffer for the data and copy it from the buffer with header prepended
1155 */
1156 new_data = kmalloc(count + sizeof(struct r3964_block_header),
1157 GFP_KERNEL);
1158 TRACE_M("r3964_write - kmalloc %p", new_data);
1159 if (new_data == NULL) {
1160 if (pInfo->flags & R3964_DEBUG) {
1161 printk(KERN_ERR "r3964_write: no memory\n");
1162 }
1163 return -ENOSPC;
1164 }
1165
1166 pHeader = (struct r3964_block_header *)new_data;
1167 pHeader->data = new_data + sizeof(struct r3964_block_header);
1168 pHeader->length = count;
1169 pHeader->locks = 0;
1170 pHeader->owner = NULL;
1171
1172 pClient = findClient(pInfo, task_pid(current));
1173 if (pClient) {
1174 pHeader->owner = pClient;
1175 }
1176
1177 memcpy(pHeader->data, data, count); /* We already verified this */
1178
1179 if (pInfo->flags & R3964_DEBUG) {
1180 dump_block(pHeader->data, count);
1181 }
1182
1183 /*
1184 * Add buffer to transmit-queue:
1185 */
1186 add_tx_queue(pInfo, pHeader);
1187 trigger_transmit(pInfo);
1188
1189 return 0;
1190 }
1191
1192 static int r3964_ioctl(struct tty_struct *tty, struct file *file,
1193 unsigned int cmd, unsigned long arg)
1194 {
1195 struct r3964_info *pInfo = tty->disc_data;
1196 if (pInfo == NULL)
1197 return -EINVAL;
1198 switch (cmd) {
1199 case R3964_ENABLE_SIGNALS:
1200 return enable_signals(pInfo, task_pid(current), arg);
1201 case R3964_SETPRIORITY:
1202 if (arg < R3964_MASTER || arg > R3964_SLAVE)
1203 return -EINVAL;
1204 pInfo->priority = arg & 0xff;
1205 return 0;
1206 case R3964_USE_BCC:
1207 if (arg)
1208 pInfo->flags |= R3964_BCC;
1209 else
1210 pInfo->flags &= ~R3964_BCC;
1211 return 0;
1212 case R3964_READ_TELEGRAM:
1213 return read_telegram(pInfo, task_pid(current),
1214 (unsigned char __user *)arg);
1215 default:
1216 return -ENOIOCTLCMD;
1217 }
1218 }
1219
1220 #ifdef CONFIG_COMPAT
1221 static int r3964_compat_ioctl(struct tty_struct *tty, struct file *file,
1222 unsigned int cmd, unsigned long arg)
1223 {
1224 switch (cmd) {
1225 case R3964_ENABLE_SIGNALS:
1226 case R3964_SETPRIORITY:
1227 case R3964_USE_BCC:
1228 return r3964_ioctl(tty, file, cmd, arg);
1229 default:
1230 return -ENOIOCTLCMD;
1231 }
1232 }
1233 #endif
1234
1235 static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old)
1236 {
1237 TRACE_L("set_termios");
1238 }
1239
1240 /* Called without the kernel lock held - fine */
1241 static __poll_t r3964_poll(struct tty_struct *tty, struct file *file,
1242 struct poll_table_struct *wait)
1243 {
1244 struct r3964_info *pInfo = tty->disc_data;
1245 struct r3964_client_info *pClient;
1246 struct r3964_message *pMsg = NULL;
1247 unsigned long flags;
1248 __poll_t result = EPOLLOUT;
1249
1250 TRACE_L("POLL");
1251
1252 pClient = findClient(pInfo, task_pid(current));
1253 if (pClient) {
1254 poll_wait(file, &tty->read_wait, wait);
1255 spin_lock_irqsave(&pInfo->lock, flags);
1256 pMsg = pClient->first_msg;
1257 spin_unlock_irqrestore(&pInfo->lock, flags);
1258 if (pMsg)
1259 result |= EPOLLIN | EPOLLRDNORM;
1260 } else {
1261 result = -EINVAL;
1262 }
1263 return result;
1264 }
1265
1266 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1267 char *fp, int count)
1268 {
1269 struct r3964_info *pInfo = tty->disc_data;
1270 const unsigned char *p;
1271 char *f, flags = TTY_NORMAL;
1272 int i;
1273
1274 for (i = count, p = cp, f = fp; i; i--, p++) {
1275 if (f)
1276 flags = *f++;
1277 if (flags == TTY_NORMAL) {
1278 receive_char(pInfo, *p);
1279 } else {
1280 receive_error(pInfo, flags);
1281 }
1282
1283 }
1284 }
1285
1286 MODULE_LICENSE("GPL");
1287 MODULE_ALIAS_LDISC(N_R3964);
Linux with added FPC-III support