Linux 2.6.31-rc6
[linux-2.6] / drivers / isdn / pcbit / layer2.c
1 /*
2  * PCBIT-D low-layer interface
3  *
4  * Copyright (C) 1996 Universidade de Lisboa
5  *
6  * Written by Pedro Roque Marques (roque@di.fc.ul.pt)
7  *
8  * This software may be used and distributed according to the terms of
9  * the GNU General Public License, incorporated herein by reference.
10  */
11
12 /*
13  * 19991203 - Fernando Carvalho - takion@superbofh.org
14  * Hacked to compile with egcs and run with current version of isdn modules
15 */
16
17 /*
18  *        Based on documentation provided by Inesc:
19  *        - "Interface com bus do PC para o PCBIT e PCBIT-D", Inesc, Jan 93
20  */
21
22 /*
23  *        TODO: better handling of errors
24  *              re-write/remove debug printks
25  */
26
27 #include <linux/string.h>
28 #include <linux/kernel.h>
29 #include <linux/types.h>
30 #include <linux/slab.h>
31 #include <linux/interrupt.h>
32 #include <linux/workqueue.h>
33 #include <linux/mm.h>
34 #include <linux/skbuff.h>
35
36 #include <linux/isdnif.h>
37
38 #include <asm/system.h>
39 #include <asm/io.h>
40
41
42 #include "pcbit.h"
43 #include "layer2.h"
44 #include "edss1.h"
45
46 #undef DEBUG_FRAG
47
48
49 /*
50  *  Prototypes
51  */
52
53 static void pcbit_transmit(struct pcbit_dev *dev);
54
55 static void pcbit_recv_ack(struct pcbit_dev *dev, unsigned char ack);
56
57 static void pcbit_l2_error(struct pcbit_dev *dev);
58 static void pcbit_l2_active_conf(struct pcbit_dev *dev, u_char info);
59 static void pcbit_l2_err_recover(unsigned long data);
60
61 static void pcbit_firmware_bug(struct pcbit_dev *dev);
62
63 static __inline__ void
64 pcbit_sched_delivery(struct pcbit_dev *dev)
65 {
66         schedule_work(&dev->qdelivery);
67 }
68
69
70 /*
71  *  Called from layer3
72  */
73
74 int
75 pcbit_l2_write(struct pcbit_dev *dev, ulong msg, ushort refnum,
76                struct sk_buff *skb, unsigned short hdr_len)
77 {
78         struct frame_buf *frame,
79         *ptr;
80         unsigned long flags;
81
82         if (dev->l2_state != L2_RUNNING && dev->l2_state != L2_LOADING) {
83                 dev_kfree_skb(skb);
84                 return -1;
85         }
86         if ((frame = kmalloc(sizeof(struct frame_buf),
87                                                   GFP_ATOMIC)) == NULL) {
88                 printk(KERN_WARNING "pcbit_2_write: kmalloc failed\n");
89                 dev_kfree_skb(skb);
90                 return -1;
91         }
92         frame->msg = msg;
93         frame->refnum = refnum;
94         frame->copied = 0;
95         frame->hdr_len = hdr_len;
96
97         if (skb)
98                 frame->dt_len = skb->len - hdr_len;
99         else
100                 frame->dt_len = 0;
101
102         frame->skb = skb;
103
104         frame->next = NULL;
105
106         spin_lock_irqsave(&dev->lock, flags);
107
108         if (dev->write_queue == NULL) {
109                 dev->write_queue = frame;
110                 spin_unlock_irqrestore(&dev->lock, flags);
111                 pcbit_transmit(dev);
112         } else {
113                 for (ptr = dev->write_queue; ptr->next; ptr = ptr->next);
114                 ptr->next = frame;
115
116                 spin_unlock_irqrestore(&dev->lock, flags);
117         }
118         return 0;
119 }
120
121 static __inline__ void
122 pcbit_tx_update(struct pcbit_dev *dev, ushort len)
123 {
124         u_char info;
125
126         dev->send_seq = (dev->send_seq + 1) % 8;
127
128         dev->fsize[dev->send_seq] = len;
129         info = 0;
130         info |= dev->rcv_seq << 3;
131         info |= dev->send_seq;
132
133         writeb(info, dev->sh_mem + BANK4);
134
135 }
136
137 /*
138  * called by interrupt service routine or by write_2
139  */
140
141 static void
142 pcbit_transmit(struct pcbit_dev *dev)
143 {
144         struct frame_buf *frame = NULL;
145         unsigned char unacked;
146         int flen;               /* fragment frame length including all headers */
147         int free;
148         int count,
149          cp_len;
150         unsigned long flags;
151         unsigned short tt;
152
153         if (dev->l2_state != L2_RUNNING && dev->l2_state != L2_LOADING)
154                 return;
155
156         unacked = (dev->send_seq + (8 - dev->unack_seq)) & 0x07;
157
158         spin_lock_irqsave(&dev->lock, flags);
159
160         if (dev->free > 16 && dev->write_queue && unacked < 7) {
161
162                 if (!dev->w_busy)
163                         dev->w_busy = 1;
164                 else {
165                         spin_unlock_irqrestore(&dev->lock, flags);
166                         return;
167                 }
168
169
170                 frame = dev->write_queue;
171                 free = dev->free;
172
173                 spin_unlock_irqrestore(&dev->lock, flags);
174
175                 if (frame->copied == 0) {
176
177                         /* Type 0 frame */
178
179                         ulong   msg;
180
181                         if (frame->skb)
182                                 flen = FRAME_HDR_LEN + PREHDR_LEN + frame->skb->len;
183                         else
184                                 flen = FRAME_HDR_LEN + PREHDR_LEN;
185
186                         if (flen > free)
187                                 flen = free;
188
189                         msg = frame->msg;
190
191                         /*
192                          *  Board level 2 header
193                          */
194
195                         pcbit_writew(dev, flen - FRAME_HDR_LEN);
196
197                         pcbit_writeb(dev, GET_MSG_CPU(msg));
198
199                         pcbit_writeb(dev, GET_MSG_PROC(msg));
200
201                         /* TH */
202                         pcbit_writew(dev, frame->hdr_len + PREHDR_LEN);
203
204                         /* TD */
205                         pcbit_writew(dev, frame->dt_len);
206
207
208                         /*
209                          *  Board level 3 fixed-header
210                          */
211
212                         /* LEN = TH */
213                         pcbit_writew(dev, frame->hdr_len + PREHDR_LEN);
214
215                         /* XX */
216                         pcbit_writew(dev, 0);
217
218                         /* C + S */
219                         pcbit_writeb(dev, GET_MSG_CMD(msg));
220                         pcbit_writeb(dev, GET_MSG_SCMD(msg));
221
222                         /* NUM */
223                         pcbit_writew(dev, frame->refnum);
224
225                         count = FRAME_HDR_LEN + PREHDR_LEN;
226                 } else {
227                         /* Type 1 frame */
228
229                         flen = 2 + (frame->skb->len - frame->copied);
230
231                         if (flen > free)
232                                 flen = free;
233
234                         /* TT */
235                         tt = ((ushort) (flen - 2)) | 0x8000U;   /* Type 1 */
236                         pcbit_writew(dev, tt);
237
238                         count = 2;
239                 }
240
241                 if (frame->skb) {
242                         cp_len = frame->skb->len - frame->copied;
243                         if (cp_len > flen - count)
244                                 cp_len = flen - count;
245
246                         memcpy_topcbit(dev, frame->skb->data + frame->copied,
247                                        cp_len);
248                         frame->copied += cp_len;
249                 }
250                 /* bookkeeping */
251                 dev->free -= flen;
252                 pcbit_tx_update(dev, flen);
253
254                 spin_lock_irqsave(&dev->lock, flags);
255
256                 if (frame->skb == NULL || frame->copied == frame->skb->len) {
257
258                         dev->write_queue = frame->next;
259
260                         if (frame->skb != NULL) {
261                                 /* free frame */
262                                 dev_kfree_skb(frame->skb);
263                         }
264                         kfree(frame);
265                 }
266                 dev->w_busy = 0;
267                 spin_unlock_irqrestore(&dev->lock, flags);
268         } else {
269                 spin_unlock_irqrestore(&dev->lock, flags);
270 #ifdef DEBUG
271                 printk(KERN_DEBUG "unacked %d free %d write_queue %s\n",
272                      unacked, dev->free, dev->write_queue ? "not empty" :
273                        "empty");
274 #endif
275         }
276 }
277
278
279 /*
280  *  deliver a queued frame to the upper layer
281  */
282
283 void
284 pcbit_deliver(struct work_struct *work)
285 {
286         struct frame_buf *frame;
287         unsigned long flags, msg;
288         struct pcbit_dev *dev =
289                 container_of(work, struct pcbit_dev, qdelivery);
290
291         spin_lock_irqsave(&dev->lock, flags);
292
293         while ((frame = dev->read_queue)) {
294                 dev->read_queue = frame->next;
295                 spin_unlock_irqrestore(&dev->lock, flags);
296
297                 msg = 0;
298                 SET_MSG_CPU(msg, 0);
299                 SET_MSG_PROC(msg, 0);
300                 SET_MSG_CMD(msg, frame->skb->data[2]);
301                 SET_MSG_SCMD(msg, frame->skb->data[3]);
302
303                 frame->refnum = *((ushort *) frame->skb->data + 4);
304                 frame->msg = *((ulong *) & msg);
305
306                 skb_pull(frame->skb, 6);
307
308                 pcbit_l3_receive(dev, frame->msg, frame->skb, frame->hdr_len,
309                                  frame->refnum);
310
311                 kfree(frame);
312
313                 spin_lock_irqsave(&dev->lock, flags);
314         }
315
316         spin_unlock_irqrestore(&dev->lock, flags);
317 }
318
319 /*
320  * Reads BANK 2 & Reassembles
321  */
322
323 static void
324 pcbit_receive(struct pcbit_dev *dev)
325 {
326         unsigned short tt;
327         u_char cpu,
328          proc;
329         struct frame_buf *frame = NULL;
330         unsigned long flags;
331         u_char type1;
332
333         if (dev->l2_state != L2_RUNNING && dev->l2_state != L2_LOADING)
334                 return;
335
336         tt = pcbit_readw(dev);
337
338         if ((tt & 0x7fffU) > 511) {
339                 printk(KERN_INFO "pcbit: invalid frame length -> TT=%04x\n",
340                        tt);
341                 pcbit_l2_error(dev);
342                 return;
343         }
344         if (!(tt & 0x8000U)) {  /* Type 0 */
345                 type1 = 0;
346
347                 if (dev->read_frame) {
348                         printk(KERN_DEBUG "pcbit_receive: Type 0 frame and read_frame != NULL\n");
349                         /* discard previous queued frame */
350                         kfree_skb(dev->read_frame->skb);
351                         kfree(dev->read_frame);
352                         dev->read_frame = NULL;
353                 }
354                 frame = kzalloc(sizeof(struct frame_buf), GFP_ATOMIC);
355
356                 if (frame == NULL) {
357                         printk(KERN_WARNING "kmalloc failed\n");
358                         return;
359                 }
360
361                 cpu = pcbit_readb(dev);
362                 proc = pcbit_readb(dev);
363
364
365                 if (cpu != 0x06 && cpu != 0x02) {
366                         printk(KERN_DEBUG "pcbit: invalid cpu value\n");
367                         kfree(frame);
368                         pcbit_l2_error(dev);
369                         return;
370                 }
371                 /*
372                  * we discard cpu & proc on receiving
373                  * but we read it to update the pointer
374                  */
375
376                 frame->hdr_len = pcbit_readw(dev);
377                 frame->dt_len = pcbit_readw(dev);
378
379                 /*
380                    * 0 sized packet
381                    * I don't know if they are an error or not...
382                    * But they are very frequent
383                    * Not documented
384                  */
385
386                 if (frame->hdr_len == 0) {
387                         kfree(frame);
388 #ifdef DEBUG
389                         printk(KERN_DEBUG "0 sized frame\n");
390 #endif
391                         pcbit_firmware_bug(dev);
392                         return;
393                 }
394                 /* sanity check the length values */
395                 if (frame->hdr_len > 1024 || frame->dt_len > 2048) {
396 #ifdef DEBUG
397                         printk(KERN_DEBUG "length problem: ");
398                         printk(KERN_DEBUG "TH=%04x TD=%04x\n",
399                                frame->hdr_len,
400                                frame->dt_len);
401 #endif
402                         pcbit_l2_error(dev);
403                         kfree(frame);
404                         return;
405                 }
406                 /* minimum frame read */
407
408                 frame->skb = dev_alloc_skb(frame->hdr_len + frame->dt_len +
409                                            ((frame->hdr_len + 15) & ~15));
410
411                 if (!frame->skb) {
412                         printk(KERN_DEBUG "pcbit_receive: out of memory\n");
413                         kfree(frame);
414                         return;
415                 }
416                 /* 16 byte alignment for IP */
417                 if (frame->dt_len)
418                         skb_reserve(frame->skb, (frame->hdr_len + 15) & ~15);
419
420         } else {
421                 /* Type 1 */
422                 type1 = 1;
423                 tt &= 0x7fffU;
424
425                 if (!(frame = dev->read_frame)) {
426                         printk("Type 1 frame and no frame queued\n");
427                         /* usually after an error: toss frame */
428                         dev->readptr += tt;
429                         if (dev->readptr > dev->sh_mem + BANK2 + BANKLEN)
430                                 dev->readptr -= BANKLEN;
431                         return;
432
433                 }
434         }
435
436         memcpy_frompcbit(dev, skb_put(frame->skb, tt), tt);
437
438         frame->copied += tt;
439         spin_lock_irqsave(&dev->lock, flags);
440         if (frame->copied == frame->hdr_len + frame->dt_len) {
441
442                 if (type1) {
443                         dev->read_frame = NULL;
444                 }
445                 if (dev->read_queue) {
446                         struct frame_buf *ptr;
447                         for (ptr = dev->read_queue; ptr->next; ptr = ptr->next);
448                         ptr->next = frame;
449                 } else
450                         dev->read_queue = frame;
451
452         } else {
453                 dev->read_frame = frame;
454         }
455         spin_unlock_irqrestore(&dev->lock, flags);
456 }
457
458 /*
459  *  The board sends 0 sized frames
460  *  They are TDATA_CONFs that get messed up somehow
461  *  gotta send a fake acknowledgment to the upper layer somehow
462  */
463
464 static __inline__ void
465 pcbit_fake_conf(struct pcbit_dev *dev, struct pcbit_chan *chan)
466 {
467         isdn_ctrl ictl;
468
469         if (chan->queued) {
470                 chan->queued--;
471
472                 ictl.driver = dev->id;
473                 ictl.command = ISDN_STAT_BSENT;
474                 ictl.arg = chan->id;
475                 dev->dev_if->statcallb(&ictl);
476         }
477 }
478
479 static void
480 pcbit_firmware_bug(struct pcbit_dev *dev)
481 {
482         struct pcbit_chan *chan;
483
484         chan = dev->b1;
485
486         if (chan->fsm_state == ST_ACTIVE) {
487                 pcbit_fake_conf(dev, chan);
488         }
489         chan = dev->b2;
490
491         if (chan->fsm_state == ST_ACTIVE) {
492                 pcbit_fake_conf(dev, chan);
493         }
494 }
495
496 irqreturn_t
497 pcbit_irq_handler(int interrupt, void *devptr)
498 {
499         struct pcbit_dev *dev;
500         u_char info,
501          ack_seq,
502          read_seq;
503
504         dev = (struct pcbit_dev *) devptr;
505
506         if (!dev) {
507                 printk(KERN_WARNING "pcbit_irq_handler: wrong device\n");
508                 return IRQ_NONE;
509         }
510         if (dev->interrupt) {
511                 printk(KERN_DEBUG "pcbit: reentering interrupt hander\n");
512                 return IRQ_HANDLED;
513         }
514         dev->interrupt = 1;
515
516         info = readb(dev->sh_mem + BANK3);
517
518         if (dev->l2_state == L2_STARTING || dev->l2_state == L2_ERROR) {
519                 pcbit_l2_active_conf(dev, info);
520                 dev->interrupt = 0;
521                 return IRQ_HANDLED;
522         }
523         if (info & 0x40U) {     /* E bit set */
524 #ifdef DEBUG
525                 printk(KERN_DEBUG "pcbit_irq_handler: E bit on\n");
526 #endif
527                 pcbit_l2_error(dev);
528                 dev->interrupt = 0;
529                 return IRQ_HANDLED;
530         }
531         if (dev->l2_state != L2_RUNNING && dev->l2_state != L2_LOADING) {
532                 dev->interrupt = 0;
533                 return IRQ_HANDLED;
534         }
535         ack_seq = (info >> 3) & 0x07U;
536         read_seq = (info & 0x07U);
537
538         dev->interrupt = 0;
539
540         if (read_seq != dev->rcv_seq) {
541                 while (read_seq != dev->rcv_seq) {
542                         pcbit_receive(dev);
543                         dev->rcv_seq = (dev->rcv_seq + 1) % 8;
544                 }
545                 pcbit_sched_delivery(dev);
546         }
547         if (ack_seq != dev->unack_seq) {
548                 pcbit_recv_ack(dev, ack_seq);
549         }
550         info = dev->rcv_seq << 3;
551         info |= dev->send_seq;
552
553         writeb(info, dev->sh_mem + BANK4);
554         return IRQ_HANDLED;
555 }
556
557
558 static void
559 pcbit_l2_active_conf(struct pcbit_dev *dev, u_char info)
560 {
561         u_char state;
562
563         state = dev->l2_state;
564
565 #ifdef DEBUG
566         printk(KERN_DEBUG "layer2_active_confirm\n");
567 #endif
568
569
570         if (info & 0x80U) {
571                 dev->rcv_seq = info & 0x07U;
572                 dev->l2_state = L2_RUNNING;
573         } else
574                 dev->l2_state = L2_DOWN;
575
576         if (state == L2_STARTING)
577                 wake_up_interruptible(&dev->set_running_wq);
578
579         if (state == L2_ERROR && dev->l2_state == L2_RUNNING) {
580                 pcbit_transmit(dev);
581         }
582 }
583
584 static void
585 pcbit_l2_err_recover(unsigned long data)
586 {
587
588         struct pcbit_dev *dev;
589         struct frame_buf *frame;
590
591         dev = (struct pcbit_dev *) data;
592
593         del_timer(&dev->error_recover_timer);
594         if (dev->w_busy || dev->r_busy) {
595                 init_timer(&dev->error_recover_timer);
596                 dev->error_recover_timer.expires = jiffies + ERRTIME;
597                 add_timer(&dev->error_recover_timer);
598                 return;
599         }
600         dev->w_busy = dev->r_busy = 1;
601
602         if (dev->read_frame) {
603                 kfree_skb(dev->read_frame->skb);
604                 kfree(dev->read_frame);
605                 dev->read_frame = NULL;
606         }
607         if (dev->write_queue) {
608                 frame = dev->write_queue;
609 #ifdef FREE_ON_ERROR
610                 dev->write_queue = dev->write_queue->next;
611
612                 if (frame->skb) {
613                         dev_kfree_skb(frame->skb);
614                 }
615                 kfree(frame);
616 #else
617                 frame->copied = 0;
618 #endif
619         }
620         dev->rcv_seq = dev->send_seq = dev->unack_seq = 0;
621         dev->free = 511;
622         dev->l2_state = L2_ERROR;
623
624         /* this is an hack... */
625         pcbit_firmware_bug(dev);
626
627         dev->writeptr = dev->sh_mem;
628         dev->readptr = dev->sh_mem + BANK2;
629
630         writeb((0x80U | ((dev->rcv_seq & 0x07) << 3) | (dev->send_seq & 0x07)),
631                dev->sh_mem + BANK4);
632         dev->w_busy = dev->r_busy = 0;
633
634 }
635
636 static void
637 pcbit_l2_error(struct pcbit_dev *dev)
638 {
639         if (dev->l2_state == L2_RUNNING) {
640
641                 printk(KERN_INFO "pcbit: layer 2 error\n");
642
643 #ifdef DEBUG
644                 log_state(dev);
645 #endif
646
647                 dev->l2_state = L2_DOWN;
648
649                 init_timer(&dev->error_recover_timer);
650                 dev->error_recover_timer.function = &pcbit_l2_err_recover;
651                 dev->error_recover_timer.data = (ulong) dev;
652                 dev->error_recover_timer.expires = jiffies + ERRTIME;
653                 add_timer(&dev->error_recover_timer);
654         }
655 }
656
657 /*
658  * Description:
659  * if board acks frames
660  *   update dev->free
661  *   call pcbit_transmit to write possible queued frames
662  */
663
664 static void
665 pcbit_recv_ack(struct pcbit_dev *dev, unsigned char ack)
666 {
667         int i,
668          count;
669         int unacked;
670
671         unacked = (dev->send_seq + (8 - dev->unack_seq)) & 0x07;
672
673         /* dev->unack_seq < ack <= dev->send_seq; */
674
675         if (unacked) {
676
677                 if (dev->send_seq > dev->unack_seq) {
678                         if (ack <= dev->unack_seq || ack > dev->send_seq) {
679                                 printk(KERN_DEBUG
680                                      "layer 2 ack unacceptable - dev %d",
681                                        dev->id);
682
683                                 pcbit_l2_error(dev);
684                         } else if (ack > dev->send_seq && ack <= dev->unack_seq) {
685                                 printk(KERN_DEBUG
686                                      "layer 2 ack unacceptable - dev %d",
687                                        dev->id);
688                                 pcbit_l2_error(dev);
689                         }
690                 }
691                 /* ack is acceptable */
692
693
694                 i = dev->unack_seq;
695
696                 do {
697                         dev->unack_seq = i = (i + 1) % 8;
698                         dev->free += dev->fsize[i];
699                 } while (i != ack);
700
701                 count = 0;
702                 while (count < 7 && dev->write_queue) {
703                         u8 lsend_seq = dev->send_seq;
704
705                         pcbit_transmit(dev);
706
707                         if (dev->send_seq == lsend_seq)
708                                 break;
709                         count++;
710                 }
711         } else
712                 printk(KERN_DEBUG "recv_ack: unacked = 0\n");
713 }