drivers/isdn/mISDN/hwchannel.c

   1 /*
   2  *
   3  * Author       Karsten Keil <kkeil@novell.com>
   4  *
   5  * Copyright 2008  by Karsten Keil <kkeil@novell.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  */
  17
  18 #include <linux/gfp.h>
  19 #include <linux/module.h>
  20 #include <linux/mISDNhw.h>
  21
  22 static void
  23 dchannel_bh(struct work_struct *ws)
  24 {
  25         struct dchannel *dch  = container_of(ws, struct dchannel, workq);
  26         struct sk_buff  *skb;
  27         int             err;
  28
  29         if (test_and_clear_bit(FLG_RECVQUEUE, &dch->Flags)) {
  30                 while ((skb = skb_dequeue(&dch->rqueue))) {
  31                         if (likely(dch->dev.D.peer)) {
  32                                 err = dch->dev.D.recv(dch->dev.D.peer, skb);
  33                                 if (err)
  34                                         dev_kfree_skb(skb);
  35                         } else
  36                                 dev_kfree_skb(skb);
  37                 }
  38         }
  39         if (test_and_clear_bit(FLG_PHCHANGE, &dch->Flags)) {
  40                 if (dch->phfunc)
  41                         dch->phfunc(dch);
  42         }
  43 }
  44
  45 static void
  46 bchannel_bh(struct work_struct *ws)
  47 {
  48         struct bchannel *bch  = container_of(ws, struct bchannel, workq);
  49         struct sk_buff  *skb;
  50         int             err;
  51
  52         if (test_and_clear_bit(FLG_RECVQUEUE, &bch->Flags)) {
  53                 while ((skb = skb_dequeue(&bch->rqueue))) {
  54                         bch->rcount--;
  55                         if (likely(bch->ch.peer)) {
  56                                 err = bch->ch.recv(bch->ch.peer, skb);
  57                                 if (err)
  58                                         dev_kfree_skb(skb);
  59                         } else
  60                                 dev_kfree_skb(skb);
  61                 }
  62         }
  63 }
  64
  65 int
  66 mISDN_initdchannel(struct dchannel *ch, int maxlen, void *phf)
  67 {
  68         test_and_set_bit(FLG_HDLC, &ch->Flags);
  69         ch->maxlen = maxlen;
  70         ch->hw = NULL;
  71         ch->rx_skb = NULL;
  72         ch->tx_skb = NULL;
  73         ch->tx_idx = 0;
  74         ch->phfunc = phf;
  75         skb_queue_head_init(&ch->squeue);
  76         skb_queue_head_init(&ch->rqueue);
  77         INIT_LIST_HEAD(&ch->dev.bchannels);
  78         INIT_WORK(&ch->workq, dchannel_bh);
  79         return 0;
  80 }
  81 EXPORT_SYMBOL(mISDN_initdchannel);
  82
  83 int
  84 mISDN_initbchannel(struct bchannel *ch, unsigned short maxlen,
  85                    unsigned short minlen)
  86 {
  87         ch->Flags = 0;
  88         ch->minlen = minlen;
  89         ch->next_minlen = minlen;
  90         ch->init_minlen = minlen;
  91         ch->maxlen = maxlen;
  92         ch->next_maxlen = maxlen;
  93         ch->init_maxlen = maxlen;
  94         ch->hw = NULL;
  95         ch->rx_skb = NULL;
  96         ch->tx_skb = NULL;
  97         ch->tx_idx = 0;
  98         skb_queue_head_init(&ch->rqueue);
  99         ch->rcount = 0;
 100         ch->next_skb = NULL;
 101         INIT_WORK(&ch->workq, bchannel_bh);
 102         return 0;
 103 }
 104 EXPORT_SYMBOL(mISDN_initbchannel);
 105
 106 int
 107 mISDN_freedchannel(struct dchannel *ch)
 108 {
 109         if (ch->tx_skb) {
 110                 dev_kfree_skb(ch->tx_skb);
 111                 ch->tx_skb = NULL;
 112         }
 113         if (ch->rx_skb) {
 114                 dev_kfree_skb(ch->rx_skb);
 115                 ch->rx_skb = NULL;
 116         }
 117         skb_queue_purge(&ch->squeue);
 118         skb_queue_purge(&ch->rqueue);
 119         flush_work_sync(&ch->workq);
 120         return 0;
 121 }
 122 EXPORT_SYMBOL(mISDN_freedchannel);
 123
 124 void
 125 mISDN_clear_bchannel(struct bchannel *ch)
 126 {
 127         if (ch->tx_skb) {
 128                 dev_kfree_skb(ch->tx_skb);
 129                 ch->tx_skb = NULL;
 130         }
 131         ch->tx_idx = 0;
 132         if (ch->rx_skb) {
 133                 dev_kfree_skb(ch->rx_skb);
 134                 ch->rx_skb = NULL;
 135         }
 136         if (ch->next_skb) {
 137                 dev_kfree_skb(ch->next_skb);
 138                 ch->next_skb = NULL;
 139         }
 140         test_and_clear_bit(FLG_TX_BUSY, &ch->Flags);
 141         test_and_clear_bit(FLG_TX_NEXT, &ch->Flags);
 142         test_and_clear_bit(FLG_ACTIVE, &ch->Flags);
 143         test_and_clear_bit(FLG_FILLEMPTY, &ch->Flags);
 144         test_and_clear_bit(FLG_TX_EMPTY, &ch->Flags);
 145         test_and_clear_bit(FLG_RX_OFF, &ch->Flags);
 146         ch->dropcnt = 0;
 147         ch->minlen = ch->init_minlen;
 148         ch->next_minlen = ch->init_minlen;
 149         ch->maxlen = ch->init_maxlen;
 150         ch->next_maxlen = ch->init_maxlen;
 151 }
 152 EXPORT_SYMBOL(mISDN_clear_bchannel);
 153
 154 int
 155 mISDN_freebchannel(struct bchannel *ch)
 156 {
 157         mISDN_clear_bchannel(ch);
 158         skb_queue_purge(&ch->rqueue);
 159         ch->rcount = 0;
 160         flush_work_sync(&ch->workq);
 161         return 0;
 162 }
 163 EXPORT_SYMBOL(mISDN_freebchannel);
 164
 165 int
 166 mISDN_ctrl_bchannel(struct bchannel *bch, struct mISDN_ctrl_req *cq)
 167 {
 168         int ret = 0;
 169
 170         switch (cq->op) {
 171         case MISDN_CTRL_GETOP:
 172                 cq->op = MISDN_CTRL_RX_BUFFER | MISDN_CTRL_FILL_EMPTY |
 173                          MISDN_CTRL_RX_OFF;
 174                 break;
 175         case MISDN_CTRL_FILL_EMPTY:
 176                 if (cq->p1) {
 177                         memset(bch->fill, cq->p2 & 0xff, MISDN_BCH_FILL_SIZE);
 178                         test_and_set_bit(FLG_FILLEMPTY, &bch->Flags);
 179                 } else {
 180                         test_and_clear_bit(FLG_FILLEMPTY, &bch->Flags);
 181                 }
 182                 break;
 183         case MISDN_CTRL_RX_OFF:
 184                 /* read back dropped byte count */
 185                 cq->p2 = bch->dropcnt;
 186                 if (cq->p1)
 187                         test_and_set_bit(FLG_RX_OFF, &bch->Flags);
 188                 else
 189                         test_and_clear_bit(FLG_RX_OFF, &bch->Flags);
 190                 bch->dropcnt = 0;
 191                 break;
 192         case MISDN_CTRL_RX_BUFFER:
 193                 if (cq->p2 > MISDN_CTRL_RX_SIZE_IGNORE)
 194                         bch->next_maxlen = cq->p2;
 195                 if (cq->p1 > MISDN_CTRL_RX_SIZE_IGNORE)
 196                         bch->next_minlen = cq->p1;
 197                 /* we return the old values */
 198                 cq->p1 = bch->minlen;
 199                 cq->p2 = bch->maxlen;
 200                 break;
 201         default:
 202                 pr_info("mISDN unhandled control %x operation\n", cq->op);
 203                 ret = -EINVAL;
 204                 break;
 205         }
 206         return ret;
 207 }
 208 EXPORT_SYMBOL(mISDN_ctrl_bchannel);
 209
 210 static inline u_int
 211 get_sapi_tei(u_char *p)
 212 {
 213         u_int   sapi, tei;
 214
 215         sapi = *p >> 2;
 216         tei = p[1] >> 1;
 217         return sapi | (tei << 8);
 218 }
 219
 220 void
 221 recv_Dchannel(struct dchannel *dch)
 222 {
 223         struct mISDNhead *hh;
 224
 225         if (dch->rx_skb->len < 2) { /* at least 2 for sapi / tei */
 226                 dev_kfree_skb(dch->rx_skb);
 227                 dch->rx_skb = NULL;
 228                 return;
 229         }
 230         hh = mISDN_HEAD_P(dch->rx_skb);
 231         hh->prim = PH_DATA_IND;
 232         hh->id = get_sapi_tei(dch->rx_skb->data);
 233         skb_queue_tail(&dch->rqueue, dch->rx_skb);
 234         dch->rx_skb = NULL;
 235         schedule_event(dch, FLG_RECVQUEUE);
 236 }
 237 EXPORT_SYMBOL(recv_Dchannel);
 238
 239 void
 240 recv_Echannel(struct dchannel *ech, struct dchannel *dch)
 241 {
 242         struct mISDNhead *hh;
 243
 244         if (ech->rx_skb->len < 2) { /* at least 2 for sapi / tei */
 245                 dev_kfree_skb(ech->rx_skb);
 246                 ech->rx_skb = NULL;
 247                 return;
 248         }
 249         hh = mISDN_HEAD_P(ech->rx_skb);
 250         hh->prim = PH_DATA_E_IND;
 251         hh->id = get_sapi_tei(ech->rx_skb->data);
 252         skb_queue_tail(&dch->rqueue, ech->rx_skb);
 253         ech->rx_skb = NULL;
 254         schedule_event(dch, FLG_RECVQUEUE);
 255 }
 256 EXPORT_SYMBOL(recv_Echannel);
 257
 258 void
 259 recv_Bchannel(struct bchannel *bch, unsigned int id, bool force)
 260 {
 261         struct mISDNhead *hh;
 262
 263         /* if allocation did fail upper functions still may call us */
 264         if (unlikely(!bch->rx_skb))
 265                 return;
 266         if (unlikely(!bch->rx_skb->len)) {
 267                 /* we have no data to send - this may happen after recovery
 268                  * from overflow or too small allocation.
 269                  * We need to free the buffer here */
 270                 dev_kfree_skb(bch->rx_skb);
 271                 bch->rx_skb = NULL;
 272         } else {
 273                 if (test_bit(FLG_TRANSPARENT, &bch->Flags) &&
 274                     (bch->rx_skb->len < bch->minlen) && !force)
 275                                 return;
 276                 hh = mISDN_HEAD_P(bch->rx_skb);
 277                 hh->prim = PH_DATA_IND;
 278                 hh->id = id;
 279                 if (bch->rcount >= 64) {
 280                         printk(KERN_WARNING
 281                                "B%d receive queue overflow - flushing!\n",
 282                                bch->nr);
 283                         skb_queue_purge(&bch->rqueue);
 284                 }
 285                 bch->rcount++;
 286                 skb_queue_tail(&bch->rqueue, bch->rx_skb);
 287                 bch->rx_skb = NULL;
 288                 schedule_event(bch, FLG_RECVQUEUE);
 289         }
 290 }
 291 EXPORT_SYMBOL(recv_Bchannel);
 292
 293 void
 294 recv_Dchannel_skb(struct dchannel *dch, struct sk_buff *skb)
 295 {
 296         skb_queue_tail(&dch->rqueue, skb);
 297         schedule_event(dch, FLG_RECVQUEUE);
 298 }
 299 EXPORT_SYMBOL(recv_Dchannel_skb);
 300
 301 void
 302 recv_Bchannel_skb(struct bchannel *bch, struct sk_buff *skb)
 303 {
 304         if (bch->rcount >= 64) {
 305                 printk(KERN_WARNING "B-channel %p receive queue overflow, "
 306                        "flushing!\n", bch);
 307                 skb_queue_purge(&bch->rqueue);
 308                 bch->rcount = 0;
 309         }
 310         bch->rcount++;
 311         skb_queue_tail(&bch->rqueue, skb);
 312         schedule_event(bch, FLG_RECVQUEUE);
 313 }
 314 EXPORT_SYMBOL(recv_Bchannel_skb);
 315
 316 static void
 317 confirm_Dsend(struct dchannel *dch)
 318 {
 319         struct sk_buff  *skb;
 320
 321         skb = _alloc_mISDN_skb(PH_DATA_CNF, mISDN_HEAD_ID(dch->tx_skb),
 322                                0, NULL, GFP_ATOMIC);
 323         if (!skb) {
 324                 printk(KERN_ERR "%s: no skb id %x\n", __func__,
 325                        mISDN_HEAD_ID(dch->tx_skb));
 326                 return;
 327         }
 328         skb_queue_tail(&dch->rqueue, skb);
 329         schedule_event(dch, FLG_RECVQUEUE);
 330 }
 331
 332 int
 333 get_next_dframe(struct dchannel *dch)
 334 {
 335         dch->tx_idx = 0;
 336         dch->tx_skb = skb_dequeue(&dch->squeue);
 337         if (dch->tx_skb) {
 338                 confirm_Dsend(dch);
 339                 return 1;
 340         }
 341         dch->tx_skb = NULL;
 342         test_and_clear_bit(FLG_TX_BUSY, &dch->Flags);
 343         return 0;
 344 }
 345 EXPORT_SYMBOL(get_next_dframe);
 346
 347 static void
 348 confirm_Bsend(struct bchannel *bch)
 349 {
 350         struct sk_buff  *skb;
 351
 352         if (bch->rcount >= 64) {
 353                 printk(KERN_WARNING "B-channel %p receive queue overflow, "
 354                        "flushing!\n", bch);
 355                 skb_queue_purge(&bch->rqueue);
 356                 bch->rcount = 0;
 357         }
 358         skb = _alloc_mISDN_skb(PH_DATA_CNF, mISDN_HEAD_ID(bch->tx_skb),
 359                                0, NULL, GFP_ATOMIC);
 360         if (!skb) {
 361                 printk(KERN_ERR "%s: no skb id %x\n", __func__,
 362                        mISDN_HEAD_ID(bch->tx_skb));
 363                 return;
 364         }
 365         bch->rcount++;
 366         skb_queue_tail(&bch->rqueue, skb);
 367         schedule_event(bch, FLG_RECVQUEUE);
 368 }
 369
 370 int
 371 get_next_bframe(struct bchannel *bch)
 372 {
 373         bch->tx_idx = 0;
 374         if (test_bit(FLG_TX_NEXT, &bch->Flags)) {
 375                 bch->tx_skb = bch->next_skb;
 376                 if (bch->tx_skb) {
 377                         bch->next_skb = NULL;
 378                         test_and_clear_bit(FLG_TX_NEXT, &bch->Flags);
 379                         /* confirm imediately to allow next data */
 380                         confirm_Bsend(bch);
 381                         return 1;
 382                 } else {
 383                         test_and_clear_bit(FLG_TX_NEXT, &bch->Flags);
 384                         printk(KERN_WARNING "B TX_NEXT without skb\n");
 385                 }
 386         }
 387         bch->tx_skb = NULL;
 388         test_and_clear_bit(FLG_TX_BUSY, &bch->Flags);
 389         return 0;
 390 }
 391 EXPORT_SYMBOL(get_next_bframe);
 392
 393 void
 394 queue_ch_frame(struct mISDNchannel *ch, u_int pr, int id, struct sk_buff *skb)
 395 {
 396         struct mISDNhead *hh;
 397
 398         if (!skb) {
 399                 _queue_data(ch, pr, id, 0, NULL, GFP_ATOMIC);
 400         } else {
 401                 if (ch->peer) {
 402                         hh = mISDN_HEAD_P(skb);
 403                         hh->prim = pr;
 404                         hh->id = id;
 405                         if (!ch->recv(ch->peer, skb))
 406                                 return;
 407                 }
 408                 dev_kfree_skb(skb);
 409         }
 410 }
 411 EXPORT_SYMBOL(queue_ch_frame);
 412
 413 int
 414 dchannel_senddata(struct dchannel *ch, struct sk_buff *skb)
 415 {
 416         /* check oversize */
 417         if (skb->len <= 0) {
 418                 printk(KERN_WARNING "%s: skb too small\n", __func__);
 419                 return -EINVAL;
 420         }
 421         if (skb->len > ch->maxlen) {
 422                 printk(KERN_WARNING "%s: skb too large(%d/%d)\n",
 423                        __func__, skb->len, ch->maxlen);
 424                 return -EINVAL;
 425         }
 426         /* HW lock must be obtained */
 427         if (test_and_set_bit(FLG_TX_BUSY, &ch->Flags)) {
 428                 skb_queue_tail(&ch->squeue, skb);
 429                 return 0;
 430         } else {
 431                 /* write to fifo */
 432                 ch->tx_skb = skb;
 433                 ch->tx_idx = 0;
 434                 return 1;
 435         }
 436 }
 437 EXPORT_SYMBOL(dchannel_senddata);
 438
 439 int
 440 bchannel_senddata(struct bchannel *ch, struct sk_buff *skb)
 441 {
 442
 443         /* check oversize */
 444         if (skb->len <= 0) {
 445                 printk(KERN_WARNING "%s: skb too small\n", __func__);
 446                 return -EINVAL;
 447         }
 448         if (skb->len > ch->maxlen) {
 449                 printk(KERN_WARNING "%s: skb too large(%d/%d)\n",
 450                        __func__, skb->len, ch->maxlen);
 451                 return -EINVAL;
 452         }
 453         /* HW lock must be obtained */
 454         /* check for pending next_skb */
 455         if (ch->next_skb) {
 456                 printk(KERN_WARNING
 457                        "%s: next_skb exist ERROR (skb->len=%d next_skb->len=%d)\n",
 458                        __func__, skb->len, ch->next_skb->len);
 459                 return -EBUSY;
 460         }
 461         if (test_and_set_bit(FLG_TX_BUSY, &ch->Flags)) {
 462                 test_and_set_bit(FLG_TX_NEXT, &ch->Flags);
 463                 ch->next_skb = skb;
 464                 return 0;
 465         } else {
 466                 /* write to fifo */
 467                 ch->tx_skb = skb;
 468                 ch->tx_idx = 0;
 469                 confirm_Bsend(ch);
 470                 return 1;
 471         }
 472 }
 473 EXPORT_SYMBOL(bchannel_senddata);
 474
 475 /* The function allocates a new receive skb on demand with a size for the
 476  * requirements of the current protocol. It returns the tailroom of the
 477  * receive skb or an error.
 478  */
 479 int
 480 bchannel_get_rxbuf(struct bchannel *bch, int reqlen)
 481 {
 482         int len;
 483
 484         if (bch->rx_skb) {
 485                 len = skb_tailroom(bch->rx_skb);
 486                 if (len < reqlen) {
 487                         pr_warning("B%d no space for %d (only %d) bytes\n",
 488                                    bch->nr, reqlen, len);
 489                         if (test_bit(FLG_TRANSPARENT, &bch->Flags)) {
 490                                 /* send what we have now and try a new buffer */
 491                                 recv_Bchannel(bch, 0, true);
 492                         } else {
 493                                 /* on HDLC we have to drop too big frames */
 494                                 return -EMSGSIZE;
 495                         }
 496                 } else {
 497                         return len;
 498                 }
 499         }
 500         /* update current min/max length first */
 501         if (unlikely(bch->maxlen != bch->next_maxlen))
 502                 bch->maxlen = bch->next_maxlen;
 503         if (unlikely(bch->minlen != bch->next_minlen))
 504                 bch->minlen = bch->next_minlen;
 505         if (unlikely(reqlen > bch->maxlen))
 506                 return -EMSGSIZE;
 507         if (test_bit(FLG_TRANSPARENT, &bch->Flags)) {
 508                 if (reqlen >= bch->minlen) {
 509                         len = reqlen;
 510                 } else {
 511                         len = 2 * bch->minlen;
 512                         if (len > bch->maxlen)
 513                                 len = bch->maxlen;
 514                 }
 515         } else {
 516                 /* with HDLC we do not know the length yet */
 517                 len = bch->maxlen;
 518         }
 519         bch->rx_skb = mI_alloc_skb(len, GFP_ATOMIC);
 520         if (!bch->rx_skb) {
 521                 pr_warning("B%d receive no memory for %d bytes\n",
 522                            bch->nr, len);
 523                 len = -ENOMEM;
 524         }
 525         return len;
 526 }
 527 EXPORT_SYMBOL(bchannel_get_rxbuf);