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                         if (dev->read_frame->skb)
 351                                 kfree_skb(dev->read_frame->skb);
 352                         kfree(dev->read_frame);
 353                         dev->read_frame = NULL;
 354                 }
 355                 frame = kzalloc(sizeof(struct frame_buf), GFP_ATOMIC);
 356
 357                 if (frame == NULL) {
 358                         printk(KERN_WARNING "kmalloc failed\n");
 359                         return;
 360                 }
 361
 362                 cpu = pcbit_readb(dev);
 363                 proc = pcbit_readb(dev);
 364
 365
 366                 if (cpu != 0x06 && cpu != 0x02) {
 367                         printk(KERN_DEBUG "pcbit: invalid cpu value\n");
 368                         kfree(frame);
 369                         pcbit_l2_error(dev);
 370                         return;
 371                 }
 372                 /*
 373                  * we discard cpu & proc on receiving
 374                  * but we read it to update the pointer
 375                  */
 376
 377                 frame->hdr_len = pcbit_readw(dev);
 378                 frame->dt_len = pcbit_readw(dev);
 379
 380                 /*
 381                    * 0 sized packet
 382                    * I don't know if they are an error or not...
 383                    * But they are very frequent
 384                    * Not documented
 385                  */
 386
 387                 if (frame->hdr_len == 0) {
 388                         kfree(frame);
 389 #ifdef DEBUG
 390                         printk(KERN_DEBUG "0 sized frame\n");
 391 #endif
 392                         pcbit_firmware_bug(dev);
 393                         return;
 394                 }
 395                 /* sanity check the length values */
 396                 if (frame->hdr_len > 1024 || frame->dt_len > 2048) {
 397 #ifdef DEBUG
 398                         printk(KERN_DEBUG "length problem: ");
 399                         printk(KERN_DEBUG "TH=%04x TD=%04x\n",
 400                                frame->hdr_len,
 401                                frame->dt_len);
 402 #endif
 403                         pcbit_l2_error(dev);
 404                         kfree(frame);
 405                         return;
 406                 }
 407                 /* minimum frame read */
 408
 409                 frame->skb = dev_alloc_skb(frame->hdr_len + frame->dt_len +
 410                                            ((frame->hdr_len + 15) & ~15));
 411
 412                 if (!frame->skb) {
 413                         printk(KERN_DEBUG "pcbit_receive: out of memory\n");
 414                         kfree(frame);
 415                         return;
 416                 }
 417                 /* 16 byte alignment for IP */
 418                 if (frame->dt_len)
 419                         skb_reserve(frame->skb, (frame->hdr_len + 15) & ~15);
 420
 421         } else {
 422                 /* Type 1 */
 423                 type1 = 1;
 424                 tt &= 0x7fffU;
 425
 426                 if (!(frame = dev->read_frame)) {
 427                         printk("Type 1 frame and no frame queued\n");
 428                         /* usually after an error: toss frame */
 429                         dev->readptr += tt;
 430                         if (dev->readptr > dev->sh_mem + BANK2 + BANKLEN)
 431                                 dev->readptr -= BANKLEN;
 432                         return;
 433
 434                 }
 435         }
 436
 437         memcpy_frompcbit(dev, skb_put(frame->skb, tt), tt);
 438
 439         frame->copied += tt;
 440         spin_lock_irqsave(&dev->lock, flags);
 441         if (frame->copied == frame->hdr_len + frame->dt_len) {
 442
 443                 if (type1) {
 444                         dev->read_frame = NULL;
 445                 }
 446                 if (dev->read_queue) {
 447                         struct frame_buf *ptr;
 448                         for (ptr = dev->read_queue; ptr->next; ptr = ptr->next);
 449                         ptr->next = frame;
 450                 } else
 451                         dev->read_queue = frame;
 452
 453         } else {
 454                 dev->read_frame = frame;
 455         }
 456         spin_unlock_irqrestore(&dev->lock, flags);
 457 }
 458
 459 /*
 460  *  The board sends 0 sized frames
 461  *  They are TDATA_CONFs that get messed up somehow
 462  *  gotta send a fake acknowledgment to the upper layer somehow
 463  */
 464
 465 static __inline__ void
 466 pcbit_fake_conf(struct pcbit_dev *dev, struct pcbit_chan *chan)
 467 {
 468         isdn_ctrl ictl;
 469
 470         if (chan->queued) {
 471                 chan->queued--;
 472
 473                 ictl.driver = dev->id;
 474                 ictl.command = ISDN_STAT_BSENT;
 475                 ictl.arg = chan->id;
 476                 dev->dev_if->statcallb(&ictl);
 477         }
 478 }
 479
 480 static void
 481 pcbit_firmware_bug(struct pcbit_dev *dev)
 482 {
 483         struct pcbit_chan *chan;
 484
 485         chan = dev->b1;
 486
 487         if (chan->fsm_state == ST_ACTIVE) {
 488                 pcbit_fake_conf(dev, chan);
 489         }
 490         chan = dev->b2;
 491
 492         if (chan->fsm_state == ST_ACTIVE) {
 493                 pcbit_fake_conf(dev, chan);
 494         }
 495 }
 496
 497 irqreturn_t
 498 pcbit_irq_handler(int interrupt, void *devptr)
 499 {
 500         struct pcbit_dev *dev;
 501         u_char info,
 502          ack_seq,
 503          read_seq;
 504
 505         dev = (struct pcbit_dev *) devptr;
 506
 507         if (!dev) {
 508                 printk(KERN_WARNING "pcbit_irq_handler: wrong device\n");
 509                 return IRQ_NONE;
 510         }
 511         if (dev->interrupt) {
 512                 printk(KERN_DEBUG "pcbit: reentering interrupt hander\n");
 513                 return IRQ_HANDLED;
 514         }
 515         dev->interrupt = 1;
 516
 517         info = readb(dev->sh_mem + BANK3);
 518
 519         if (dev->l2_state == L2_STARTING || dev->l2_state == L2_ERROR) {
 520                 pcbit_l2_active_conf(dev, info);
 521                 dev->interrupt = 0;
 522                 return IRQ_HANDLED;
 523         }
 524         if (info & 0x40U) {     /* E bit set */
 525 #ifdef DEBUG
 526                 printk(KERN_DEBUG "pcbit_irq_handler: E bit on\n");
 527 #endif
 528                 pcbit_l2_error(dev);
 529                 dev->interrupt = 0;
 530                 return IRQ_HANDLED;
 531         }
 532         if (dev->l2_state != L2_RUNNING && dev->l2_state != L2_LOADING) {
 533                 dev->interrupt = 0;
 534                 return IRQ_HANDLED;
 535         }
 536         ack_seq = (info >> 3) & 0x07U;
 537         read_seq = (info & 0x07U);
 538
 539         dev->interrupt = 0;
 540
 541         if (read_seq != dev->rcv_seq) {
 542                 while (read_seq != dev->rcv_seq) {
 543                         pcbit_receive(dev);
 544                         dev->rcv_seq = (dev->rcv_seq + 1) % 8;
 545                 }
 546                 pcbit_sched_delivery(dev);
 547         }
 548         if (ack_seq != dev->unack_seq) {
 549                 pcbit_recv_ack(dev, ack_seq);
 550         }
 551         info = dev->rcv_seq << 3;
 552         info |= dev->send_seq;
 553
 554         writeb(info, dev->sh_mem + BANK4);
 555         return IRQ_HANDLED;
 556 }
 557
 558
 559 static void
 560 pcbit_l2_active_conf(struct pcbit_dev *dev, u_char info)
 561 {
 562         u_char state;
 563
 564         state = dev->l2_state;
 565
 566 #ifdef DEBUG
 567         printk(KERN_DEBUG "layer2_active_confirm\n");
 568 #endif
 569
 570
 571         if (info & 0x80U) {
 572                 dev->rcv_seq = info & 0x07U;
 573                 dev->l2_state = L2_RUNNING;
 574         } else
 575                 dev->l2_state = L2_DOWN;
 576
 577         if (state == L2_STARTING)
 578                 wake_up_interruptible(&dev->set_running_wq);
 579
 580         if (state == L2_ERROR && dev->l2_state == L2_RUNNING) {
 581                 pcbit_transmit(dev);
 582         }
 583 }
 584
 585 static void
 586 pcbit_l2_err_recover(unsigned long data)
 587 {
 588
 589         struct pcbit_dev *dev;
 590         struct frame_buf *frame;
 591
 592         dev = (struct pcbit_dev *) data;
 593
 594         del_timer(&dev->error_recover_timer);
 595         if (dev->w_busy || dev->r_busy) {
 596                 init_timer(&dev->error_recover_timer);
 597                 dev->error_recover_timer.expires = jiffies + ERRTIME;
 598                 add_timer(&dev->error_recover_timer);
 599                 return;
 600         }
 601         dev->w_busy = dev->r_busy = 1;
 602
 603         if (dev->read_frame) {
 604                 if (dev->read_frame->skb)
 605                         kfree_skb(dev->read_frame->skb);
 606                 kfree(dev->read_frame);
 607                 dev->read_frame = NULL;
 608         }
 609         if (dev->write_queue) {
 610                 frame = dev->write_queue;
 611 #ifdef FREE_ON_ERROR
 612                 dev->write_queue = dev->write_queue->next;
 613
 614                 if (frame->skb) {
 615                         dev_kfree_skb(frame->skb);
 616                 }
 617                 kfree(frame);
 618 #else
 619                 frame->copied = 0;
 620 #endif
 621         }
 622         dev->rcv_seq = dev->send_seq = dev->unack_seq = 0;
 623         dev->free = 511;
 624         dev->l2_state = L2_ERROR;
 625
 626         /* this is an hack... */
 627         pcbit_firmware_bug(dev);
 628
 629         dev->writeptr = dev->sh_mem;
 630         dev->readptr = dev->sh_mem + BANK2;
 631
 632         writeb((0x80U | ((dev->rcv_seq & 0x07) << 3) | (dev->send_seq & 0x07)),
 633                dev->sh_mem + BANK4);
 634         dev->w_busy = dev->r_busy = 0;
 635
 636 }
 637
 638 static void
 639 pcbit_l2_error(struct pcbit_dev *dev)
 640 {
 641         if (dev->l2_state == L2_RUNNING) {
 642
 643                 printk(KERN_INFO "pcbit: layer 2 error\n");
 644
 645 #ifdef DEBUG
 646                 log_state(dev);
 647 #endif
 648
 649                 dev->l2_state = L2_DOWN;
 650
 651                 init_timer(&dev->error_recover_timer);
 652                 dev->error_recover_timer.function = &pcbit_l2_err_recover;
 653                 dev->error_recover_timer.data = (ulong) dev;
 654                 dev->error_recover_timer.expires = jiffies + ERRTIME;
 655                 add_timer(&dev->error_recover_timer);
 656         }
 657 }
 658
 659 /*
 660  * Description:
 661  * if board acks frames
 662  *   update dev->free
 663  *   call pcbit_transmit to write possible queued frames
 664  */
 665
 666 static void
 667 pcbit_recv_ack(struct pcbit_dev *dev, unsigned char ack)
 668 {
 669         int i,
 670          count;
 671         int unacked;
 672
 673         unacked = (dev->send_seq + (8 - dev->unack_seq)) & 0x07;
 674
 675         /* dev->unack_seq < ack <= dev->send_seq; */
 676
 677         if (unacked) {
 678
 679                 if (dev->send_seq > dev->unack_seq) {
 680                         if (ack <= dev->unack_seq || ack > dev->send_seq) {
 681                                 printk(KERN_DEBUG
 682                                      "layer 2 ack unacceptable - dev %d",
 683                                        dev->id);
 684
 685                                 pcbit_l2_error(dev);
 686                         } else if (ack > dev->send_seq && ack <= dev->unack_seq) {
 687                                 printk(KERN_DEBUG
 688                                      "layer 2 ack unacceptable - dev %d",
 689                                        dev->id);
 690                                 pcbit_l2_error(dev);
 691                         }
 692                 }
 693                 /* ack is acceptable */
 694
 695
 696                 i = dev->unack_seq;
 697
 698                 do {
 699                         dev->unack_seq = i = (i + 1) % 8;
 700                         dev->free += dev->fsize[i];
 701                 } while (i != ack);
 702
 703                 count = 0;
 704                 while (count < 7 && dev->write_queue) {
 705                         u8 lsend_seq = dev->send_seq;
 706
 707                         pcbit_transmit(dev);
 708
 709                         if (dev->send_seq == lsend_seq)
 710                                 break;
 711                         count++;
 712                 }
 713         } else
 714                 printk(KERN_DEBUG "recv_ack: unacked = 0\n");
 715 }