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/sched.h>
  28 #include <linux/string.h>
  29 #include <linux/kernel.h>
  30 #include <linux/types.h>
  31 #include <linux/slab.h>
  32 #include <linux/interrupt.h>
  33 #include <linux/workqueue.h>
  34 #include <linux/mm.h>
  35 #include <linux/skbuff.h>
  36
  37 #include <linux/isdnif.h>
  38
  39 #include <asm/system.h>
  40 #include <asm/io.h>
  41
  42
  43 #include "pcbit.h"
  44 #include "layer2.h"
  45 #include "edss1.h"
  46
  47 #undef DEBUG_FRAG
  48
  49
  50
  51 /*
  52  *  task queue struct
  53  */
  54
  55
  56
  57 /*
  58  *  Layer 3 packet demultiplexer
  59  *  drv.c
  60  */
  61
  62 extern void pcbit_l3_receive(struct pcbit_dev *dev, ulong msg,
  63                              struct sk_buff *skb,
  64                              ushort hdr_len, ushort refnum);
  65
  66 /*
  67  *  Prototypes
  68  */
  69
  70 static void pcbit_transmit(struct pcbit_dev *dev);
  71
  72 static void pcbit_recv_ack(struct pcbit_dev *dev, unsigned char ack);
  73
  74 static void pcbit_l2_error(struct pcbit_dev *dev);
  75 static void pcbit_l2_active_conf(struct pcbit_dev *dev, u_char info);
  76 static void pcbit_l2_err_recover(unsigned long data);
  77
  78 static void pcbit_firmware_bug(struct pcbit_dev *dev);
  79
  80 static __inline__ void
  81 pcbit_sched_delivery(struct pcbit_dev *dev)
  82 {
  83         schedule_work(&dev->qdelivery);
  84 }
  85
  86
  87 /*
  88  *  Called from layer3
  89  */
  90
  91 int
  92 pcbit_l2_write(struct pcbit_dev *dev, ulong msg, ushort refnum,
  93                struct sk_buff *skb, unsigned short hdr_len)
  94 {
  95         struct frame_buf *frame,
  96         *ptr;
  97         unsigned long flags;
  98
  99         if (dev->l2_state != L2_RUNNING && dev->l2_state != L2_LOADING) {
 100                 dev_kfree_skb(skb);
 101                 return -1;
 102         }
 103         if ((frame = (struct frame_buf *) kmalloc(sizeof(struct frame_buf),
 104                                                   GFP_ATOMIC)) == NULL) {
 105                 printk(KERN_WARNING "pcbit_2_write: kmalloc failed\n");
 106                 dev_kfree_skb(skb);
 107                 return -1;
 108         }
 109         frame->msg = msg;
 110         frame->refnum = refnum;
 111         frame->copied = 0;
 112         frame->hdr_len = hdr_len;
 113
 114         if (skb)
 115                 frame->dt_len = skb->len - hdr_len;
 116         else
 117                 frame->dt_len = 0;
 118
 119         frame->skb = skb;
 120
 121         frame->next = NULL;
 122
 123         spin_lock_irqsave(&dev->lock, flags);
 124
 125         if (dev->write_queue == NULL) {
 126                 dev->write_queue = frame;
 127                 spin_unlock_irqrestore(&dev->lock, flags);
 128                 pcbit_transmit(dev);
 129         } else {
 130                 for (ptr = dev->write_queue; ptr->next; ptr = ptr->next);
 131                 ptr->next = frame;
 132
 133                 spin_unlock_irqrestore(&dev->lock, flags);
 134         }
 135         return 0;
 136 }
 137
 138 static __inline__ void
 139 pcbit_tx_update(struct pcbit_dev *dev, ushort len)
 140 {
 141         u_char info;
 142
 143         dev->send_seq = (dev->send_seq + 1) % 8;
 144
 145         dev->fsize[dev->send_seq] = len;
 146         info = 0;
 147         info |= dev->rcv_seq << 3;
 148         info |= dev->send_seq;
 149
 150         writeb(info, dev->sh_mem + BANK4);
 151
 152 }
 153
 154 /*
 155  * called by interrupt service routine or by write_2
 156  */
 157
 158 static void
 159 pcbit_transmit(struct pcbit_dev *dev)
 160 {
 161         struct frame_buf *frame = NULL;
 162         unsigned char unacked;
 163         int flen;               /* fragment frame length including all headers */
 164         int free;
 165         int count,
 166          cp_len;
 167         unsigned long flags;
 168         unsigned short tt;
 169
 170         if (dev->l2_state != L2_RUNNING && dev->l2_state != L2_LOADING)
 171                 return;
 172
 173         unacked = (dev->send_seq + (8 - dev->unack_seq)) & 0x07;
 174
 175         spin_lock_irqsave(&dev->lock, flags);
 176
 177         if (dev->free > 16 && dev->write_queue && unacked < 7) {
 178
 179                 if (!dev->w_busy)
 180                         dev->w_busy = 1;
 181                 else {
 182                         spin_unlock_irqrestore(&dev->lock, flags);
 183                         return;
 184                 }
 185
 186
 187                 frame = dev->write_queue;
 188                 free = dev->free;
 189
 190                 spin_unlock_irqrestore(&dev->lock, flags);
 191
 192                 if (frame->copied == 0) {
 193
 194                         /* Type 0 frame */
 195
 196                         ulong   msg;
 197
 198                         if (frame->skb)
 199                                 flen = FRAME_HDR_LEN + PREHDR_LEN + frame->skb->len;
 200                         else
 201                                 flen = FRAME_HDR_LEN + PREHDR_LEN;
 202
 203                         if (flen > free)
 204                                 flen = free;
 205
 206                         msg = frame->msg;
 207
 208                         /*
 209                          *  Board level 2 header
 210                          */
 211
 212                         pcbit_writew(dev, flen - FRAME_HDR_LEN);
 213
 214                         pcbit_writeb(dev, GET_MSG_CPU(msg));
 215
 216                         pcbit_writeb(dev, GET_MSG_PROC(msg));
 217
 218                         /* TH */
 219                         pcbit_writew(dev, frame->hdr_len + PREHDR_LEN);
 220
 221                         /* TD */
 222                         pcbit_writew(dev, frame->dt_len);
 223
 224
 225                         /*
 226                          *  Board level 3 fixed-header
 227                          */
 228
 229                         /* LEN = TH */
 230                         pcbit_writew(dev, frame->hdr_len + PREHDR_LEN);
 231
 232                         /* XX */
 233                         pcbit_writew(dev, 0);
 234
 235                         /* C + S */
 236                         pcbit_writeb(dev, GET_MSG_CMD(msg));
 237                         pcbit_writeb(dev, GET_MSG_SCMD(msg));
 238
 239                         /* NUM */
 240                         pcbit_writew(dev, frame->refnum);
 241
 242                         count = FRAME_HDR_LEN + PREHDR_LEN;
 243                 } else {
 244                         /* Type 1 frame */
 245
 246                         flen = 2 + (frame->skb->len - frame->copied);
 247
 248                         if (flen > free)
 249                                 flen = free;
 250
 251                         /* TT */
 252                         tt = ((ushort) (flen - 2)) | 0x8000U;   /* Type 1 */
 253                         pcbit_writew(dev, tt);
 254
 255                         count = 2;
 256                 }
 257
 258                 if (frame->skb) {
 259                         cp_len = frame->skb->len - frame->copied;
 260                         if (cp_len > flen - count)
 261                                 cp_len = flen - count;
 262
 263                         memcpy_topcbit(dev, frame->skb->data + frame->copied,
 264                                        cp_len);
 265                         frame->copied += cp_len;
 266                 }
 267                 /* bookkeeping */
 268                 dev->free -= flen;
 269                 pcbit_tx_update(dev, flen);
 270
 271                 spin_lock_irqsave(&dev->lock, flags);
 272
 273                 if (frame->skb == NULL || frame->copied == frame->skb->len) {
 274
 275                         dev->write_queue = frame->next;
 276
 277                         if (frame->skb != NULL) {
 278                                 /* free frame */
 279                                 dev_kfree_skb(frame->skb);
 280                         }
 281                         kfree(frame);
 282                 }
 283                 dev->w_busy = 0;
 284                 spin_unlock_irqrestore(&dev->lock, flags);
 285         } else {
 286                 spin_unlock_irqrestore(&dev->lock, flags);
 287 #ifdef DEBUG
 288                 printk(KERN_DEBUG "unacked %d free %d write_queue %s\n",
 289                      unacked, dev->free, dev->write_queue ? "not empty" :
 290                        "empty");
 291 #endif
 292         }
 293 }
 294
 295
 296 /*
 297  *  deliver a queued frame to the upper layer
 298  */
 299
 300 void
 301 pcbit_deliver(struct work_struct *work)
 302 {
 303         struct frame_buf *frame;
 304         unsigned long flags, msg;
 305         struct pcbit_dev *dev =
 306                 container_of(work, struct pcbit_dev, qdelivery);
 307
 308         spin_lock_irqsave(&dev->lock, flags);
 309
 310         while ((frame = dev->read_queue)) {
 311                 dev->read_queue = frame->next;
 312                 spin_unlock_irqrestore(&dev->lock, flags);
 313
 314                 msg = 0;
 315                 SET_MSG_CPU(msg, 0);
 316                 SET_MSG_PROC(msg, 0);
 317                 SET_MSG_CMD(msg, frame->skb->data[2]);
 318                 SET_MSG_SCMD(msg, frame->skb->data[3]);
 319
 320                 frame->refnum = *((ushort *) frame->skb->data + 4);
 321                 frame->msg = *((ulong *) & msg);
 322
 323                 skb_pull(frame->skb, 6);
 324
 325                 pcbit_l3_receive(dev, frame->msg, frame->skb, frame->hdr_len,
 326                                  frame->refnum);
 327
 328                 kfree(frame);
 329
 330                 spin_lock_irqsave(&dev->lock, flags);
 331         }
 332
 333         spin_unlock_irqrestore(&dev->lock, flags);
 334 }
 335
 336 /*
 337  * Reads BANK 2 & Reassembles
 338  */
 339
 340 static void
 341 pcbit_receive(struct pcbit_dev *dev)
 342 {
 343         unsigned short tt;
 344         u_char cpu,
 345          proc;
 346         struct frame_buf *frame = NULL;
 347         unsigned long flags;
 348         u_char type1;
 349
 350         if (dev->l2_state != L2_RUNNING && dev->l2_state != L2_LOADING)
 351                 return;
 352
 353         tt = pcbit_readw(dev);
 354
 355         if ((tt & 0x7fffU) > 511) {
 356                 printk(KERN_INFO "pcbit: invalid frame length -> TT=%04x\n",
 357                        tt);
 358                 pcbit_l2_error(dev);
 359                 return;
 360         }
 361         if (!(tt & 0x8000U)) {  /* Type 0 */
 362                 type1 = 0;
 363
 364                 if (dev->read_frame) {
 365                         printk(KERN_DEBUG "pcbit_receive: Type 0 frame and read_frame != NULL\n");
 366                         /* discard previous queued frame */
 367                         if (dev->read_frame->skb)
 368                                 kfree_skb(dev->read_frame->skb);
 369                         kfree(dev->read_frame);
 370                         dev->read_frame = NULL;
 371                 }
 372                 frame = kzalloc(sizeof(struct frame_buf), GFP_ATOMIC);
 373
 374                 if (frame == NULL) {
 375                         printk(KERN_WARNING "kmalloc failed\n");
 376                         return;
 377                 }
 378
 379                 cpu = pcbit_readb(dev);
 380                 proc = pcbit_readb(dev);
 381
 382
 383                 if (cpu != 0x06 && cpu != 0x02) {
 384                         printk(KERN_DEBUG "pcbit: invalid cpu value\n");
 385                         kfree(frame);
 386                         pcbit_l2_error(dev);
 387                         return;
 388                 }
 389                 /*
 390                  * we discard cpu & proc on receiving
 391                  * but we read it to update the pointer
 392                  */
 393
 394                 frame->hdr_len = pcbit_readw(dev);
 395                 frame->dt_len = pcbit_readw(dev);
 396
 397                 /*
 398                    * 0 sized packet
 399                    * I don't know if they are an error or not...
 400                    * But they are very frequent
 401                    * Not documented
 402                  */
 403
 404                 if (frame->hdr_len == 0) {
 405                         kfree(frame);
 406 #ifdef DEBUG
 407                         printk(KERN_DEBUG "0 sized frame\n");
 408 #endif
 409                         pcbit_firmware_bug(dev);
 410                         return;
 411                 }
 412                 /* sanity check the length values */
 413                 if (frame->hdr_len > 1024 || frame->dt_len > 2048) {
 414 #ifdef DEBUG
 415                         printk(KERN_DEBUG "length problem: ");
 416                         printk(KERN_DEBUG "TH=%04x TD=%04x\n",
 417                                frame->hdr_len,
 418                                frame->dt_len);
 419 #endif
 420                         pcbit_l2_error(dev);
 421                         kfree(frame);
 422                         return;
 423                 }
 424                 /* minimum frame read */
 425
 426                 frame->skb = dev_alloc_skb(frame->hdr_len + frame->dt_len +
 427                                            ((frame->hdr_len + 15) & ~15));
 428
 429                 if (!frame->skb) {
 430                         printk(KERN_DEBUG "pcbit_receive: out of memory\n");
 431                         kfree(frame);
 432                         return;
 433                 }
 434                 /* 16 byte alignment for IP */
 435                 if (frame->dt_len)
 436                         skb_reserve(frame->skb, (frame->hdr_len + 15) & ~15);
 437
 438         } else {
 439                 /* Type 1 */
 440                 type1 = 1;
 441                 tt &= 0x7fffU;
 442
 443                 if (!(frame = dev->read_frame)) {
 444                         printk("Type 1 frame and no frame queued\n");
 445                         /* usually after an error: toss frame */
 446                         dev->readptr += tt;
 447                         if (dev->readptr > dev->sh_mem + BANK2 + BANKLEN)
 448                                 dev->readptr -= BANKLEN;
 449                         return;
 450
 451                 }
 452         }
 453
 454         memcpy_frompcbit(dev, skb_put(frame->skb, tt), tt);
 455
 456         frame->copied += tt;
 457         spin_lock_irqsave(&dev->lock, flags);
 458         if (frame->copied == frame->hdr_len + frame->dt_len) {
 459
 460                 if (type1) {
 461                         dev->read_frame = NULL;
 462                 }
 463                 if (dev->read_queue) {
 464                         struct frame_buf *ptr;
 465                         for (ptr = dev->read_queue; ptr->next; ptr = ptr->next);
 466                         ptr->next = frame;
 467                 } else
 468                         dev->read_queue = frame;
 469
 470         } else {
 471                 dev->read_frame = frame;
 472         }
 473         spin_unlock_irqrestore(&dev->lock, flags);
 474 }
 475
 476 /*
 477  *  The board sends 0 sized frames
 478  *  They are TDATA_CONFs that get messed up somehow
 479  *  gotta send a fake acknowledgment to the upper layer somehow
 480  */
 481
 482 static __inline__ void
 483 pcbit_fake_conf(struct pcbit_dev *dev, struct pcbit_chan *chan)
 484 {
 485         isdn_ctrl ictl;
 486
 487         if (chan->queued) {
 488                 chan->queued--;
 489
 490                 ictl.driver = dev->id;
 491                 ictl.command = ISDN_STAT_BSENT;
 492                 ictl.arg = chan->id;
 493                 dev->dev_if->statcallb(&ictl);
 494         }
 495 }
 496
 497 static void
 498 pcbit_firmware_bug(struct pcbit_dev *dev)
 499 {
 500         struct pcbit_chan *chan;
 501
 502         chan = dev->b1;
 503
 504         if (chan->fsm_state == ST_ACTIVE) {
 505                 pcbit_fake_conf(dev, chan);
 506         }
 507         chan = dev->b2;
 508
 509         if (chan->fsm_state == ST_ACTIVE) {
 510                 pcbit_fake_conf(dev, chan);
 511         }
 512 }
 513
 514 irqreturn_t
 515 pcbit_irq_handler(int interrupt, void *devptr)
 516 {
 517         struct pcbit_dev *dev;
 518         u_char info,
 519          ack_seq,
 520          read_seq;
 521
 522         dev = (struct pcbit_dev *) devptr;
 523
 524         if (!dev) {
 525                 printk(KERN_WARNING "pcbit_irq_handler: wrong device\n");
 526                 return IRQ_NONE;
 527         }
 528         if (dev->interrupt) {
 529                 printk(KERN_DEBUG "pcbit: reentering interrupt hander\n");
 530                 return IRQ_HANDLED;
 531         }
 532         dev->interrupt = 1;
 533
 534         info = readb(dev->sh_mem + BANK3);
 535
 536         if (dev->l2_state == L2_STARTING || dev->l2_state == L2_ERROR) {
 537                 pcbit_l2_active_conf(dev, info);
 538                 dev->interrupt = 0;
 539                 return IRQ_HANDLED;
 540         }
 541         if (info & 0x40U) {     /* E bit set */
 542 #ifdef DEBUG
 543                 printk(KERN_DEBUG "pcbit_irq_handler: E bit on\n");
 544 #endif
 545                 pcbit_l2_error(dev);
 546                 dev->interrupt = 0;
 547                 return IRQ_HANDLED;
 548         }
 549         if (dev->l2_state != L2_RUNNING && dev->l2_state != L2_LOADING) {
 550                 dev->interrupt = 0;
 551                 return IRQ_HANDLED;
 552         }
 553         ack_seq = (info >> 3) & 0x07U;
 554         read_seq = (info & 0x07U);
 555
 556         dev->interrupt = 0;
 557
 558         if (read_seq != dev->rcv_seq) {
 559                 while (read_seq != dev->rcv_seq) {
 560                         pcbit_receive(dev);
 561                         dev->rcv_seq = (dev->rcv_seq + 1) % 8;
 562                 }
 563                 pcbit_sched_delivery(dev);
 564         }
 565         if (ack_seq != dev->unack_seq) {
 566                 pcbit_recv_ack(dev, ack_seq);
 567         }
 568         info = dev->rcv_seq << 3;
 569         info |= dev->send_seq;
 570
 571         writeb(info, dev->sh_mem + BANK4);
 572         return IRQ_HANDLED;
 573 }
 574
 575
 576 static void
 577 pcbit_l2_active_conf(struct pcbit_dev *dev, u_char info)
 578 {
 579         u_char state;
 580
 581         state = dev->l2_state;
 582
 583 #ifdef DEBUG
 584         printk(KERN_DEBUG "layer2_active_confirm\n");
 585 #endif
 586
 587
 588         if (info & 0x80U) {
 589                 dev->rcv_seq = info & 0x07U;
 590                 dev->l2_state = L2_RUNNING;
 591         } else
 592                 dev->l2_state = L2_DOWN;
 593
 594         if (state == L2_STARTING)
 595                 wake_up_interruptible(&dev->set_running_wq);
 596
 597         if (state == L2_ERROR && dev->l2_state == L2_RUNNING) {
 598                 pcbit_transmit(dev);
 599         }
 600 }
 601
 602 static void
 603 pcbit_l2_err_recover(unsigned long data)
 604 {
 605
 606         struct pcbit_dev *dev;
 607         struct frame_buf *frame;
 608
 609         dev = (struct pcbit_dev *) data;
 610
 611         del_timer(&dev->error_recover_timer);
 612         if (dev->w_busy || dev->r_busy) {
 613                 init_timer(&dev->error_recover_timer);
 614                 dev->error_recover_timer.expires = jiffies + ERRTIME;
 615                 add_timer(&dev->error_recover_timer);
 616                 return;
 617         }
 618         dev->w_busy = dev->r_busy = 1;
 619
 620         if (dev->read_frame) {
 621                 if (dev->read_frame->skb)
 622                         kfree_skb(dev->read_frame->skb);
 623                 kfree(dev->read_frame);
 624                 dev->read_frame = NULL;
 625         }
 626         if (dev->write_queue) {
 627                 frame = dev->write_queue;
 628 #ifdef FREE_ON_ERROR
 629                 dev->write_queue = dev->write_queue->next;
 630
 631                 if (frame->skb) {
 632                         dev_kfree_skb(frame->skb);
 633                 }
 634                 kfree(frame);
 635 #else
 636                 frame->copied = 0;
 637 #endif
 638         }
 639         dev->rcv_seq = dev->send_seq = dev->unack_seq = 0;
 640         dev->free = 511;
 641         dev->l2_state = L2_ERROR;
 642
 643         /* this is an hack... */
 644         pcbit_firmware_bug(dev);
 645
 646         dev->writeptr = dev->sh_mem;
 647         dev->readptr = dev->sh_mem + BANK2;
 648
 649         writeb((0x80U | ((dev->rcv_seq & 0x07) << 3) | (dev->send_seq & 0x07)),
 650                dev->sh_mem + BANK4);
 651         dev->w_busy = dev->r_busy = 0;
 652
 653 }
 654
 655 static void
 656 pcbit_l2_error(struct pcbit_dev *dev)
 657 {
 658         if (dev->l2_state == L2_RUNNING) {
 659
 660                 printk(KERN_INFO "pcbit: layer 2 error\n");
 661
 662 #ifdef DEBUG
 663                 log_state(dev);
 664 #endif
 665
 666                 dev->l2_state = L2_DOWN;
 667
 668                 init_timer(&dev->error_recover_timer);
 669                 dev->error_recover_timer.function = &pcbit_l2_err_recover;
 670                 dev->error_recover_timer.data = (ulong) dev;
 671                 dev->error_recover_timer.expires = jiffies + ERRTIME;
 672                 add_timer(&dev->error_recover_timer);
 673         }
 674 }
 675
 676 /*
 677  * Description:
 678  * if board acks frames
 679  *   update dev->free
 680  *   call pcbit_transmit to write possible queued frames
 681  */
 682
 683 static void
 684 pcbit_recv_ack(struct pcbit_dev *dev, unsigned char ack)
 685 {
 686         int i,
 687          count;
 688         int unacked;
 689
 690         unacked = (dev->send_seq + (8 - dev->unack_seq)) & 0x07;
 691
 692         /* dev->unack_seq < ack <= dev->send_seq; */
 693
 694         if (unacked) {
 695
 696                 if (dev->send_seq > dev->unack_seq) {
 697                         if (ack <= dev->unack_seq || ack > dev->send_seq) {
 698                                 printk(KERN_DEBUG
 699                                      "layer 2 ack unacceptable - dev %d",
 700                                        dev->id);
 701
 702                                 pcbit_l2_error(dev);
 703                         } else if (ack > dev->send_seq && ack <= dev->unack_seq) {
 704                                 printk(KERN_DEBUG
 705                                      "layer 2 ack unacceptable - dev %d",
 706                                        dev->id);
 707                                 pcbit_l2_error(dev);
 708                         }
 709                 }
 710                 /* ack is acceptable */
 711
 712
 713                 i = dev->unack_seq;
 714
 715                 do {
 716                         dev->unack_seq = i = (i + 1) % 8;
 717                         dev->free += dev->fsize[i];
 718                 } while (i != ack);
 719
 720                 count = 0;
 721                 while (count < 7 && dev->write_queue) {
 722                         u8 lsend_seq = dev->send_seq;
 723
 724                         pcbit_transmit(dev);
 725
 726                         if (dev->send_seq == lsend_seq)
 727                                 break;
 728                         count++;
 729                 }
 730         } else
 731                 printk(KERN_DEBUG "recv_ack: unacked = 0\n");
 732 }