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80#define HDLC_MAGIC 0x239e
81
82#include <linux/module.h>
83#include <linux/init.h>
84#include <linux/kernel.h>
85#include <linux/sched.h>
86#include <linux/types.h>
87#include <linux/fcntl.h>
88#include <linux/interrupt.h>
89#include <linux/ptrace.h>
90
91#undef VERSION
92#define VERSION(major,minor,patch) (((((major)<<8)+(minor))<<8)+(patch))
93
94#include <linux/poll.h>
95#include <linux/in.h>
96#include <linux/ioctl.h>
97#include <linux/slab.h>
98#include <linux/tty.h>
99#include <linux/errno.h>
100#include <linux/smp_lock.h>
101#include <linux/string.h>
102#include <linux/signal.h>
103#include <linux/if.h>
104#include <linux/bitops.h>
105
106#include <asm/system.h>
107#include <asm/termios.h>
108#include <asm/uaccess.h>
109
110
111
112
113#define MAX_HDLC_FRAME_SIZE 65535
114#define DEFAULT_RX_BUF_COUNT 10
115#define MAX_RX_BUF_COUNT 60
116#define DEFAULT_TX_BUF_COUNT 3
117
118struct n_hdlc_buf {
119 struct n_hdlc_buf *link;
120 int count;
121 char buf[1];
122};
123
124#define N_HDLC_BUF_SIZE (sizeof(struct n_hdlc_buf) + maxframe)
125
126struct n_hdlc_buf_list {
127 struct n_hdlc_buf *head;
128 struct n_hdlc_buf *tail;
129 int count;
130 spinlock_t spinlock;
131};
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147struct n_hdlc {
148 int magic;
149 __u32 flags;
150 struct tty_struct *tty;
151 struct tty_struct *backup_tty;
152 int tbusy;
153 int woke_up;
154 struct n_hdlc_buf *tbuf;
155 struct n_hdlc_buf_list tx_buf_list;
156 struct n_hdlc_buf_list rx_buf_list;
157 struct n_hdlc_buf_list tx_free_buf_list;
158 struct n_hdlc_buf_list rx_free_buf_list;
159};
160
161
162
163
164static void n_hdlc_buf_list_init(struct n_hdlc_buf_list *list);
165static void n_hdlc_buf_put(struct n_hdlc_buf_list *list,
166 struct n_hdlc_buf *buf);
167static struct n_hdlc_buf *n_hdlc_buf_get(struct n_hdlc_buf_list *list);
168
169
170
171static struct n_hdlc *n_hdlc_alloc (void);
172
173
174#define DEBUG_LEVEL_INFO 1
175static int debuglevel;
176
177
178static int maxframe = 4096;
179
180
181
182static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file,
183 __u8 __user *buf, size_t nr);
184static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file,
185 const unsigned char *buf, size_t nr);
186static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file,
187 unsigned int cmd, unsigned long arg);
188static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp,
189 poll_table *wait);
190static int n_hdlc_tty_open(struct tty_struct *tty);
191static void n_hdlc_tty_close(struct tty_struct *tty);
192static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *cp,
193 char *fp, int count);
194static void n_hdlc_tty_wakeup(struct tty_struct *tty);
195
196#define bset(p,b) ((p)[(b) >> 5] |= (1 << ((b) & 0x1f)))
197
198#define tty2n_hdlc(tty) ((struct n_hdlc *) ((tty)->disc_data))
199#define n_hdlc2tty(n_hdlc) ((n_hdlc)->tty)
200
201static void flush_rx_queue(struct tty_struct *tty)
202{
203 struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
204 struct n_hdlc_buf *buf;
205
206 while ((buf = n_hdlc_buf_get(&n_hdlc->rx_buf_list)))
207 n_hdlc_buf_put(&n_hdlc->rx_free_buf_list, buf);
208}
209
210static void flush_tx_queue(struct tty_struct *tty)
211{
212 struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
213 struct n_hdlc_buf *buf;
214 unsigned long flags;
215
216 while ((buf = n_hdlc_buf_get(&n_hdlc->tx_buf_list)))
217 n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, buf);
218 spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
219 if (n_hdlc->tbuf) {
220 n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, n_hdlc->tbuf);
221 n_hdlc->tbuf = NULL;
222 }
223 spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
224}
225
226static struct tty_ldisc_ops n_hdlc_ldisc = {
227 .owner = THIS_MODULE,
228 .magic = TTY_LDISC_MAGIC,
229 .name = "hdlc",
230 .open = n_hdlc_tty_open,
231 .close = n_hdlc_tty_close,
232 .read = n_hdlc_tty_read,
233 .write = n_hdlc_tty_write,
234 .ioctl = n_hdlc_tty_ioctl,
235 .poll = n_hdlc_tty_poll,
236 .receive_buf = n_hdlc_tty_receive,
237 .write_wakeup = n_hdlc_tty_wakeup,
238 .flush_buffer = flush_rx_queue,
239};
240
241
242
243
244
245static void n_hdlc_release(struct n_hdlc *n_hdlc)
246{
247 struct tty_struct *tty = n_hdlc2tty (n_hdlc);
248 struct n_hdlc_buf *buf;
249
250 if (debuglevel >= DEBUG_LEVEL_INFO)
251 printk("%s(%d)n_hdlc_release() called\n",__FILE__,__LINE__);
252
253
254 wake_up_interruptible (&tty->read_wait);
255 wake_up_interruptible (&tty->write_wait);
256
257 if (tty->disc_data == n_hdlc)
258 tty->disc_data = NULL;
259
260
261 for(;;) {
262 buf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list);
263 if (buf) {
264 kfree(buf);
265 } else
266 break;
267 }
268 for(;;) {
269 buf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list);
270 if (buf) {
271 kfree(buf);
272 } else
273 break;
274 }
275 for(;;) {
276 buf = n_hdlc_buf_get(&n_hdlc->rx_buf_list);
277 if (buf) {
278 kfree(buf);
279 } else
280 break;
281 }
282 for(;;) {
283 buf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
284 if (buf) {
285 kfree(buf);
286 } else
287 break;
288 }
289 kfree(n_hdlc->tbuf);
290 kfree(n_hdlc);
291
292}
293
294
295
296
297
298
299
300
301static void n_hdlc_tty_close(struct tty_struct *tty)
302{
303 struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
304
305 if (debuglevel >= DEBUG_LEVEL_INFO)
306 printk("%s(%d)n_hdlc_tty_close() called\n",__FILE__,__LINE__);
307
308 if (n_hdlc != NULL) {
309 if (n_hdlc->magic != HDLC_MAGIC) {
310 printk (KERN_WARNING"n_hdlc: trying to close unopened tty!\n");
311 return;
312 }
313#if defined(TTY_NO_WRITE_SPLIT)
314 clear_bit(TTY_NO_WRITE_SPLIT,&tty->flags);
315#endif
316 tty->disc_data = NULL;
317 if (tty == n_hdlc->backup_tty)
318 n_hdlc->backup_tty = NULL;
319 if (tty != n_hdlc->tty)
320 return;
321 if (n_hdlc->backup_tty) {
322 n_hdlc->tty = n_hdlc->backup_tty;
323 } else {
324 n_hdlc_release (n_hdlc);
325 }
326 }
327
328 if (debuglevel >= DEBUG_LEVEL_INFO)
329 printk("%s(%d)n_hdlc_tty_close() success\n",__FILE__,__LINE__);
330
331}
332
333
334
335
336
337
338
339static int n_hdlc_tty_open (struct tty_struct *tty)
340{
341 struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
342
343 if (debuglevel >= DEBUG_LEVEL_INFO)
344 printk("%s(%d)n_hdlc_tty_open() called (device=%s)\n",
345 __FILE__,__LINE__,
346 tty->name);
347
348
349 if (n_hdlc) {
350 printk (KERN_ERR"n_hdlc_tty_open:tty already associated!\n" );
351 return -EEXIST;
352 }
353
354 n_hdlc = n_hdlc_alloc();
355 if (!n_hdlc) {
356 printk (KERN_ERR "n_hdlc_alloc failed\n");
357 return -ENFILE;
358 }
359
360 tty->disc_data = n_hdlc;
361 n_hdlc->tty = tty;
362 tty->receive_room = 65536;
363
364#if defined(TTY_NO_WRITE_SPLIT)
365
366 set_bit(TTY_NO_WRITE_SPLIT,&tty->flags);
367#endif
368
369
370 tty_driver_flush_buffer(tty);
371
372 if (debuglevel >= DEBUG_LEVEL_INFO)
373 printk("%s(%d)n_hdlc_tty_open() success\n",__FILE__,__LINE__);
374
375 return 0;
376
377}
378
379
380
381
382
383
384
385
386
387
388static void n_hdlc_send_frames(struct n_hdlc *n_hdlc, struct tty_struct *tty)
389{
390 register int actual;
391 unsigned long flags;
392 struct n_hdlc_buf *tbuf;
393
394 if (debuglevel >= DEBUG_LEVEL_INFO)
395 printk("%s(%d)n_hdlc_send_frames() called\n",__FILE__,__LINE__);
396 check_again:
397
398 spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
399 if (n_hdlc->tbusy) {
400 n_hdlc->woke_up = 1;
401 spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
402 return;
403 }
404 n_hdlc->tbusy = 1;
405 n_hdlc->woke_up = 0;
406 spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
407
408
409
410
411 tbuf = n_hdlc->tbuf;
412 if (!tbuf)
413 tbuf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
414
415 while (tbuf) {
416 if (debuglevel >= DEBUG_LEVEL_INFO)
417 printk("%s(%d)sending frame %p, count=%d\n",
418 __FILE__,__LINE__,tbuf,tbuf->count);
419
420
421 tty->flags |= (1 << TTY_DO_WRITE_WAKEUP);
422 actual = tty->ops->write(tty, tbuf->buf, tbuf->count);
423
424
425 if (actual == -ERESTARTSYS) {
426 n_hdlc->tbuf = tbuf;
427 break;
428 }
429
430
431 if (actual < 0)
432 actual = tbuf->count;
433
434 if (actual == tbuf->count) {
435 if (debuglevel >= DEBUG_LEVEL_INFO)
436 printk("%s(%d)frame %p completed\n",
437 __FILE__,__LINE__,tbuf);
438
439
440 n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, tbuf);
441
442
443 n_hdlc->tbuf = NULL;
444
445
446 wake_up_interruptible(&tty->write_wait);
447
448
449 tbuf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
450 } else {
451 if (debuglevel >= DEBUG_LEVEL_INFO)
452 printk("%s(%d)frame %p pending\n",
453 __FILE__,__LINE__,tbuf);
454
455
456
457 n_hdlc->tbuf = tbuf;
458 break;
459 }
460 }
461
462 if (!tbuf)
463 tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
464
465
466 spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
467 n_hdlc->tbusy = 0;
468 spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
469
470 if (n_hdlc->woke_up)
471 goto check_again;
472
473 if (debuglevel >= DEBUG_LEVEL_INFO)
474 printk("%s(%d)n_hdlc_send_frames() exit\n",__FILE__,__LINE__);
475
476}
477
478
479
480
481
482
483
484static void n_hdlc_tty_wakeup(struct tty_struct *tty)
485{
486 struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
487
488 if (debuglevel >= DEBUG_LEVEL_INFO)
489 printk("%s(%d)n_hdlc_tty_wakeup() called\n",__FILE__,__LINE__);
490
491 if (!n_hdlc)
492 return;
493
494 if (tty != n_hdlc->tty) {
495 tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
496 return;
497 }
498
499 n_hdlc_send_frames (n_hdlc, tty);
500
501}
502
503
504
505
506
507
508
509
510
511
512
513static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data,
514 char *flags, int count)
515{
516 register struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
517 register struct n_hdlc_buf *buf;
518
519 if (debuglevel >= DEBUG_LEVEL_INFO)
520 printk("%s(%d)n_hdlc_tty_receive() called count=%d\n",
521 __FILE__,__LINE__, count);
522
523
524 if (!n_hdlc || tty != n_hdlc->tty)
525 return;
526
527
528 if (n_hdlc->magic != HDLC_MAGIC) {
529 printk("%s(%d) line not using HDLC discipline\n",
530 __FILE__,__LINE__);
531 return;
532 }
533
534 if ( count>maxframe ) {
535 if (debuglevel >= DEBUG_LEVEL_INFO)
536 printk("%s(%d) rx count>maxframesize, data discarded\n",
537 __FILE__,__LINE__);
538 return;
539 }
540
541
542 buf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list);
543 if (!buf) {
544
545
546 if (n_hdlc->rx_buf_list.count < MAX_RX_BUF_COUNT)
547 buf = kmalloc(N_HDLC_BUF_SIZE, GFP_ATOMIC);
548 }
549
550 if (!buf) {
551 if (debuglevel >= DEBUG_LEVEL_INFO)
552 printk("%s(%d) no more rx buffers, data discarded\n",
553 __FILE__,__LINE__);
554 return;
555 }
556
557
558 memcpy(buf->buf,data,count);
559 buf->count=count;
560
561
562 n_hdlc_buf_put(&n_hdlc->rx_buf_list, buf);
563
564
565 wake_up_interruptible (&tty->read_wait);
566 if (n_hdlc->tty->fasync != NULL)
567 kill_fasync (&n_hdlc->tty->fasync, SIGIO, POLL_IN);
568
569}
570
571
572
573
574
575
576
577
578
579
580static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file,
581 __u8 __user *buf, size_t nr)
582{
583 struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
584 int ret;
585 struct n_hdlc_buf *rbuf;
586
587 if (debuglevel >= DEBUG_LEVEL_INFO)
588 printk("%s(%d)n_hdlc_tty_read() called\n",__FILE__,__LINE__);
589
590
591 if (!n_hdlc)
592 return -EIO;
593
594
595 if (!access_ok(VERIFY_WRITE, buf, nr)) {
596 printk(KERN_WARNING "%s(%d) n_hdlc_tty_read() can't verify user "
597 "buffer\n", __FILE__, __LINE__);
598 return -EFAULT;
599 }
600
601 lock_kernel();
602
603 for (;;) {
604 if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
605 unlock_kernel();
606 return -EIO;
607 }
608
609 n_hdlc = tty2n_hdlc (tty);
610 if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC ||
611 tty != n_hdlc->tty) {
612 unlock_kernel();
613 return 0;
614 }
615
616 rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list);
617 if (rbuf)
618 break;
619
620
621 if (file->f_flags & O_NONBLOCK) {
622 unlock_kernel();
623 return -EAGAIN;
624 }
625
626 interruptible_sleep_on (&tty->read_wait);
627 if (signal_pending(current)) {
628 unlock_kernel();
629 return -EINTR;
630 }
631 }
632
633 if (rbuf->count > nr)
634
635 ret = -EOVERFLOW;
636 else {
637
638 if (copy_to_user(buf, rbuf->buf, rbuf->count))
639 ret = -EFAULT;
640 else
641 ret = rbuf->count;
642 }
643
644
645
646
647 if (n_hdlc->rx_free_buf_list.count > DEFAULT_RX_BUF_COUNT)
648 kfree(rbuf);
649 else
650 n_hdlc_buf_put(&n_hdlc->rx_free_buf_list,rbuf);
651 unlock_kernel();
652 return ret;
653
654}
655
656
657
658
659
660
661
662
663
664
665static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file,
666 const unsigned char *data, size_t count)
667{
668 struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
669 int error = 0;
670 DECLARE_WAITQUEUE(wait, current);
671 struct n_hdlc_buf *tbuf;
672
673 if (debuglevel >= DEBUG_LEVEL_INFO)
674 printk("%s(%d)n_hdlc_tty_write() called count=%Zd\n",
675 __FILE__,__LINE__,count);
676
677
678 if (!n_hdlc)
679 return -EIO;
680
681 if (n_hdlc->magic != HDLC_MAGIC)
682 return -EIO;
683
684
685 if (count > maxframe ) {
686 if (debuglevel & DEBUG_LEVEL_INFO)
687 printk (KERN_WARNING
688 "n_hdlc_tty_write: truncating user packet "
689 "from %lu to %d\n", (unsigned long) count,
690 maxframe );
691 count = maxframe;
692 }
693
694 lock_kernel();
695
696 add_wait_queue(&tty->write_wait, &wait);
697 set_current_state(TASK_INTERRUPTIBLE);
698
699
700
701 while (!(tbuf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list))) {
702 if (file->f_flags & O_NONBLOCK) {
703 error = -EAGAIN;
704 break;
705 }
706 schedule();
707
708 n_hdlc = tty2n_hdlc (tty);
709 if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC ||
710 tty != n_hdlc->tty) {
711 printk("n_hdlc_tty_write: %p invalid after wait!\n", n_hdlc);
712 error = -EIO;
713 break;
714 }
715
716 if (signal_pending(current)) {
717 error = -EINTR;
718 break;
719 }
720 }
721
722 set_current_state(TASK_RUNNING);
723 remove_wait_queue(&tty->write_wait, &wait);
724
725 if (!error) {
726
727 memcpy(tbuf->buf, data, count);
728
729
730 tbuf->count = error = count;
731 n_hdlc_buf_put(&n_hdlc->tx_buf_list,tbuf);
732 n_hdlc_send_frames(n_hdlc,tty);
733 }
734 unlock_kernel();
735 return error;
736
737}
738
739
740
741
742
743
744
745
746
747
748static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file,
749 unsigned int cmd, unsigned long arg)
750{
751 struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
752 int error = 0;
753 int count;
754 unsigned long flags;
755
756 if (debuglevel >= DEBUG_LEVEL_INFO)
757 printk("%s(%d)n_hdlc_tty_ioctl() called %d\n",
758 __FILE__,__LINE__,cmd);
759
760
761 if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC)
762 return -EBADF;
763
764 switch (cmd) {
765 case FIONREAD:
766
767
768 spin_lock_irqsave(&n_hdlc->rx_buf_list.spinlock,flags);
769 if (n_hdlc->rx_buf_list.head)
770 count = n_hdlc->rx_buf_list.head->count;
771 else
772 count = 0;
773 spin_unlock_irqrestore(&n_hdlc->rx_buf_list.spinlock,flags);
774 error = put_user(count, (int __user *)arg);
775 break;
776
777 case TIOCOUTQ:
778
779 count = tty_chars_in_buffer(tty);
780
781 spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock,flags);
782 if (n_hdlc->tx_buf_list.head)
783 count += n_hdlc->tx_buf_list.head->count;
784 spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock,flags);
785 error = put_user(count, (int __user *)arg);
786 break;
787
788 case TCFLSH:
789 switch (arg) {
790 case TCIOFLUSH:
791 case TCOFLUSH:
792 flush_tx_queue(tty);
793 }
794
795
796 default:
797 error = n_tty_ioctl_helper(tty, file, cmd, arg);
798 break;
799 }
800 return error;
801
802}
803
804
805
806
807
808
809
810
811
812
813
814static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp,
815 poll_table *wait)
816{
817 struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
818 unsigned int mask = 0;
819
820 if (debuglevel >= DEBUG_LEVEL_INFO)
821 printk("%s(%d)n_hdlc_tty_poll() called\n",__FILE__,__LINE__);
822
823 if (n_hdlc && n_hdlc->magic == HDLC_MAGIC && tty == n_hdlc->tty) {
824
825
826
827 poll_wait(filp, &tty->read_wait, wait);
828 poll_wait(filp, &tty->write_wait, wait);
829
830
831 if (n_hdlc->rx_buf_list.head)
832 mask |= POLLIN | POLLRDNORM;
833 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
834 mask |= POLLHUP;
835 if (tty_hung_up_p(filp))
836 mask |= POLLHUP;
837 if (!tty_is_writelocked(tty) &&
838 n_hdlc->tx_free_buf_list.head)
839 mask |= POLLOUT | POLLWRNORM;
840 }
841 return mask;
842}
843
844
845
846
847
848
849static struct n_hdlc *n_hdlc_alloc(void)
850{
851 struct n_hdlc_buf *buf;
852 int i;
853 struct n_hdlc *n_hdlc = kmalloc(sizeof(*n_hdlc), GFP_KERNEL);
854
855 if (!n_hdlc)
856 return NULL;
857
858 memset(n_hdlc, 0, sizeof(*n_hdlc));
859
860 n_hdlc_buf_list_init(&n_hdlc->rx_free_buf_list);
861 n_hdlc_buf_list_init(&n_hdlc->tx_free_buf_list);
862 n_hdlc_buf_list_init(&n_hdlc->rx_buf_list);
863 n_hdlc_buf_list_init(&n_hdlc->tx_buf_list);
864
865
866 for(i=0;i<DEFAULT_RX_BUF_COUNT;i++) {
867 buf = kmalloc(N_HDLC_BUF_SIZE, GFP_KERNEL);
868 if (buf)
869 n_hdlc_buf_put(&n_hdlc->rx_free_buf_list,buf);
870 else if (debuglevel >= DEBUG_LEVEL_INFO)
871 printk("%s(%d)n_hdlc_alloc(), kalloc() failed for rx buffer %d\n",__FILE__,__LINE__, i);
872 }
873
874
875 for(i=0;i<DEFAULT_TX_BUF_COUNT;i++) {
876 buf = kmalloc(N_HDLC_BUF_SIZE, GFP_KERNEL);
877 if (buf)
878 n_hdlc_buf_put(&n_hdlc->tx_free_buf_list,buf);
879 else if (debuglevel >= DEBUG_LEVEL_INFO)
880 printk("%s(%d)n_hdlc_alloc(), kalloc() failed for tx buffer %d\n",__FILE__,__LINE__, i);
881 }
882
883
884 n_hdlc->magic = HDLC_MAGIC;
885 n_hdlc->flags = 0;
886
887 return n_hdlc;
888
889}
890
891
892
893
894
895static void n_hdlc_buf_list_init(struct n_hdlc_buf_list *list)
896{
897 memset(list, 0, sizeof(*list));
898 spin_lock_init(&list->spinlock);
899}
900
901
902
903
904
905
906static void n_hdlc_buf_put(struct n_hdlc_buf_list *list,
907 struct n_hdlc_buf *buf)
908{
909 unsigned long flags;
910 spin_lock_irqsave(&list->spinlock,flags);
911
912 buf->link=NULL;
913 if (list->tail)
914 list->tail->link = buf;
915 else
916 list->head = buf;
917 list->tail = buf;
918 (list->count)++;
919
920 spin_unlock_irqrestore(&list->spinlock,flags);
921
922}
923
924
925
926
927
928
929
930
931
932static struct n_hdlc_buf* n_hdlc_buf_get(struct n_hdlc_buf_list *list)
933{
934 unsigned long flags;
935 struct n_hdlc_buf *buf;
936 spin_lock_irqsave(&list->spinlock,flags);
937
938 buf = list->head;
939 if (buf) {
940 list->head = buf->link;
941 (list->count)--;
942 }
943 if (!list->head)
944 list->tail = NULL;
945
946 spin_unlock_irqrestore(&list->spinlock,flags);
947 return buf;
948
949}
950
951static char hdlc_banner[] __initdata =
952 KERN_INFO "HDLC line discipline maxframe=%u\n";
953static char hdlc_register_ok[] __initdata =
954 KERN_INFO "N_HDLC line discipline registered.\n";
955static char hdlc_register_fail[] __initdata =
956 KERN_ERR "error registering line discipline: %d\n";
957static char hdlc_init_fail[] __initdata =
958 KERN_INFO "N_HDLC: init failure %d\n";
959
960static int __init n_hdlc_init(void)
961{
962 int status;
963
964
965 if (maxframe < 4096)
966 maxframe = 4096;
967 else if (maxframe > 65535)
968 maxframe = 65535;
969
970 printk(hdlc_banner, maxframe);
971
972 status = tty_register_ldisc(N_HDLC, &n_hdlc_ldisc);
973 if (!status)
974 printk(hdlc_register_ok);
975 else
976 printk(hdlc_register_fail, status);
977
978 if (status)
979 printk(hdlc_init_fail, status);
980 return status;
981
982}
983
984static char hdlc_unregister_ok[] __exitdata =
985 KERN_INFO "N_HDLC: line discipline unregistered\n";
986static char hdlc_unregister_fail[] __exitdata =
987 KERN_ERR "N_HDLC: can't unregister line discipline (err = %d)\n";
988
989static void __exit n_hdlc_exit(void)
990{
991
992 int status = tty_unregister_ldisc(N_HDLC);
993
994 if (status)
995 printk(hdlc_unregister_fail, status);
996 else
997 printk(hdlc_unregister_ok);
998}
999
1000module_init(n_hdlc_init);
1001module_exit(n_hdlc_exit);
1002
1003MODULE_LICENSE("GPL");
1004MODULE_AUTHOR("Paul Fulghum paulkf@microgate.com");
1005module_param(debuglevel, int, 0);
1006module_param(maxframe, int, 0);
1007MODULE_ALIAS_LDISC(N_HDLC);
1008