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