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 void pcbit_deliver(void *data);
  71 static void pcbit_transmit(struct pcbit_dev *dev);
  72
  73 static void pcbit_recv_ack(struct pcbit_dev *dev, unsigned char ack);
  74
  75 static void pcbit_l2_error(struct pcbit_dev *dev);
  76 static void pcbit_l2_active_conf(struct pcbit_dev *dev, u_char info);
  77 static void pcbit_l2_err_recover(unsigned long data);
  78
  79 static void pcbit_firmware_bug(struct pcbit_dev *dev);
  80
  81 static __inline__ void
  82 pcbit_sched_delivery(struct pcbit_dev *dev)
  83 {
  84         schedule_work(&dev->qdelivery);
  85 }
  86
  87
  88 /*
  89  *  Called from layer3
  90  */
  91
  92 int
  93 pcbit_l2_write(struct pcbit_dev *dev, ulong msg, ushort refnum,
  94                struct sk_buff *skb, unsigned short hdr_len)
  95 {
  96         struct frame_buf *frame,
  97         *ptr;
  98         unsigned long flags;
  99
 100         if (dev->l2_state != L2_RUNNING && dev->l2_state != L2_LOADING) {
 101                 dev_kfree_skb(skb);
 102                 return -1;
 103         }
 104         if ((frame = (struct frame_buf *) kmalloc(sizeof(struct frame_buf),
 105                                                   GFP_ATOMIC)) == NULL) {
 106                 printk(KERN_WARNING "pcbit_2_write: kmalloc failed\n");
 107                 dev_kfree_skb(skb);
 108                 return -1;
 109         }
 110         frame->msg = msg;
 111         frame->refnum = refnum;
 112         frame->copied = 0;
 113         frame->hdr_len = hdr_len;
 114
 115         if (skb)
 116                 frame->dt_len = skb->len - hdr_len;
 117         else
 118                 frame->dt_len = 0;
 119
 120         frame->skb = skb;
 121
 122         frame->next = NULL;
 123
 124         spin_lock_irqsave(&dev->lock, flags);
 125
 126         if (dev->write_queue == NULL) {
 127                 dev->write_queue = frame;
 128                 spin_unlock_irqrestore(&dev->lock, flags);
 129                 pcbit_transmit(dev);
 130         } else {
 131                 for (ptr = dev->write_queue; ptr->next; ptr = ptr->next);
 132                 ptr->next = frame;
 133
 134                 spin_unlock_irqrestore(&dev->lock, flags);
 135         }
 136         return 0;
 137 }
 138
 139 static __inline__ void
 140 pcbit_tx_update(struct pcbit_dev *dev, ushort len)
 141 {
 142         u_char info;
 143
 144         dev->send_seq = (dev->send_seq + 1) % 8;
 145
 146         dev->fsize[dev->send_seq] = len;
 147         info = 0;
 148         info |= dev->rcv_seq << 3;
 149         info |= dev->send_seq;
 150
 151         writeb(info, dev->sh_mem + BANK4);
 152
 153 }
 154
 155 /*
 156  * called by interrupt service routine or by write_2
 157  */
 158
 159 static void
 160 pcbit_transmit(struct pcbit_dev *dev)
 161 {
 162         struct frame_buf *frame = NULL;
 163         unsigned char unacked;
 164         int flen;               /* fragment frame length including all headers */
 165         int free;
 166         int count,
 167          cp_len;
 168         unsigned long flags;
 169         unsigned short tt;
 170
 171         if (dev->l2_state != L2_RUNNING && dev->l2_state != L2_LOADING)
 172                 return;
 173
 174         unacked = (dev->send_seq + (8 - dev->unack_seq)) & 0x07;
 175
 176         spin_lock_irqsave(&dev->lock, flags);
 177
 178         if (dev->free > 16 && dev->write_queue && unacked < 7) {
 179
 180                 if (!dev->w_busy)
 181                         dev->w_busy = 1;
 182                 else {
 183                         spin_unlock_irqrestore(&dev->lock, flags);
 184                         return;
 185                 }
 186
 187
 188                 frame = dev->write_queue;
 189                 free = dev->free;
 190
 191                 spin_unlock_irqrestore(&dev->lock, flags);
 192
 193                 if (frame->copied == 0) {
 194
 195                         /* Type 0 frame */
 196
 197                         ulong   msg;
 198
 199                         if (frame->skb)
 200                                 flen = FRAME_HDR_LEN + PREHDR_LEN + frame->skb->len;
 201                         else
 202                                 flen = FRAME_HDR_LEN + PREHDR_LEN;
 203
 204                         if (flen > free)
 205                                 flen = free;
 206
 207                         msg = frame->msg;
 208
 209                         /*
 210                          *  Board level 2 header
 211                          */
 212
 213                         pcbit_writew(dev, flen - FRAME_HDR_LEN);
 214
 215                         pcbit_writeb(dev, GET_MSG_CPU(msg));
 216
 217                         pcbit_writeb(dev, GET_MSG_PROC(msg));
 218
 219                         /* TH */
 220                         pcbit_writew(dev, frame->hdr_len + PREHDR_LEN);
 221
 222                         /* TD */
 223                         pcbit_writew(dev, frame->dt_len);
 224
 225
 226                         /*
 227                          *  Board level 3 fixed-header
 228                          */
 229
 230                         /* LEN = TH */
 231                         pcbit_writew(dev, frame->hdr_len + PREHDR_LEN);
 232
 233                         /* XX */
 234                         pcbit_writew(dev, 0);
 235
 236                         /* C + S */
 237                         pcbit_writeb(dev, GET_MSG_CMD(msg));
 238                         pcbit_writeb(dev, GET_MSG_SCMD(msg));
 239
 240                         /* NUM */
 241                         pcbit_writew(dev, frame->refnum);
 242
 243                         count = FRAME_HDR_LEN + PREHDR_LEN;
 244                 } else {
 245                         /* Type 1 frame */
 246
 247                         flen = 2 + (frame->skb->len - frame->copied);
 248
 249                         if (flen > free)
 250                                 flen = free;
 251
 252                         /* TT */
 253                         tt = ((ushort) (flen - 2)) | 0x8000U;   /* Type 1 */
 254                         pcbit_writew(dev, tt);
 255
 256                         count = 2;
 257                 }
 258
 259                 if (frame->skb) {
 260                         cp_len = frame->skb->len - frame->copied;
 261                         if (cp_len > flen - count)
 262                                 cp_len = flen - count;
 263
 264                         memcpy_topcbit(dev, frame->skb->data + frame->copied,
 265                                        cp_len);
 266                         frame->copied += cp_len;
 267                 }
 268                 /* bookkeeping */
 269                 dev->free -= flen;
 270                 pcbit_tx_update(dev, flen);
 271
 272                 spin_lock_irqsave(&dev->lock, flags);
 273
 274                 if (frame->skb == NULL || frame->copied == frame->skb->len) {
 275
 276                         dev->write_queue = frame->next;
 277
 278                         if (frame->skb != NULL) {
 279                                 /* free frame */
 280                                 dev_kfree_skb(frame->skb);
 281                         }
 282                         kfree(frame);
 283                 }
 284                 dev->w_busy = 0;
 285                 spin_unlock_irqrestore(&dev->lock, flags);
 286         } else {
 287                 spin_unlock_irqrestore(&dev->lock, flags);
 288 #ifdef DEBUG
 289                 printk(KERN_DEBUG "unacked %d free %d write_queue %s\n",
 290                      unacked, dev->free, dev->write_queue ? "not empty" :
 291                        "empty");
 292 #endif
 293         }
 294 }
 295
 296
 297 /*
 298  *  deliver a queued frame to the upper layer
 299  */
 300
 301 void
 302 pcbit_deliver(void *data)
 303 {
 304         struct frame_buf *frame;
 305         unsigned long flags, msg;
 306         struct pcbit_dev *dev = (struct pcbit_dev *) data;
 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                 SET_MSG_CPU(msg, 0);
 315                 SET_MSG_PROC(msg, 0);
 316                 SET_MSG_CMD(msg, frame->skb->data[2]);
 317                 SET_MSG_SCMD(msg, frame->skb->data[3]);
 318
 319                 frame->refnum = *((ushort *) frame->skb->data + 4);
 320                 frame->msg = *((ulong *) & msg);
 321
 322                 skb_pull(frame->skb, 6);
 323
 324                 pcbit_l3_receive(dev, frame->msg, frame->skb, frame->hdr_len,
 325                                  frame->refnum);
 326
 327                 kfree(frame);
 328
 329                 spin_lock_irqsave(&dev->lock, flags);
 330         }
 331
 332         spin_unlock_irqrestore(&dev->lock, flags);
 333 }
 334
 335 /*
 336  * Reads BANK 2 & Reassembles
 337  */
 338
 339 static void
 340 pcbit_receive(struct pcbit_dev *dev)
 341 {
 342         unsigned short tt;
 343         u_char cpu,
 344          proc;
 345         struct frame_buf *frame = NULL;
 346         unsigned long flags;
 347         u_char type1;
 348
 349         if (dev->l2_state != L2_RUNNING && dev->l2_state != L2_LOADING)
 350                 return;
 351
 352         tt = pcbit_readw(dev);
 353
 354         if ((tt & 0x7fffU) > 511) {
 355                 printk(KERN_INFO "pcbit: invalid frame length -> TT=%04x\n",
 356                        tt);
 357                 pcbit_l2_error(dev);
 358                 return;
 359         }
 360         if (!(tt & 0x8000U)) {  /* Type 0 */
 361                 type1 = 0;
 362
 363                 if (dev->read_frame) {
 364                         printk(KERN_DEBUG "pcbit_receive: Type 0 frame and read_frame != NULL\n");
 365                         /* discard previous queued frame */
 366                         if (dev->read_frame->skb)
 367                                 kfree_skb(dev->read_frame->skb);
 368                         kfree(dev->read_frame);
 369                         dev->read_frame = NULL;
 370                 }
 371                 frame = kmalloc(sizeof(struct frame_buf), GFP_ATOMIC);
 372
 373                 if (frame == NULL) {
 374                         printk(KERN_WARNING "kmalloc failed\n");
 375                         return;
 376                 }
 377                 memset(frame, 0, sizeof(struct frame_buf));
 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, struct pt_regs *regs)
 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 }