kernel/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(&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         skb_queue_purge(&ch->rqueue);
 152         ch->rcount = 0;
 153 }
 154 EXPORT_SYMBOL(mISDN_clear_bchannel);
 155
 156 void
 157 mISDN_freebchannel(struct bchannel *ch)
 158 {
 159         cancel_work_sync(&ch->workq);
 160         mISDN_clear_bchannel(ch);
 161 }
 162 EXPORT_SYMBOL(mISDN_freebchannel);
 163
 164 int
 165 mISDN_ctrl_bchannel(struct bchannel *bch, struct mISDN_ctrl_req *cq)
 166 {
 167         int ret = 0;
 168
 169         switch (cq->op) {
 170         case MISDN_CTRL_GETOP:
 171                 cq->op = MISDN_CTRL_RX_BUFFER | MISDN_CTRL_FILL_EMPTY |
 172                          MISDN_CTRL_RX_OFF;
 173                 break;
 174         case MISDN_CTRL_FILL_EMPTY:
 175                 if (cq->p1) {
 176                         memset(bch->fill, cq->p2 & 0xff, MISDN_BCH_FILL_SIZE);
 177                         test_and_set_bit(FLG_FILLEMPTY, &bch->Flags);
 178                 } else {
 179                         test_and_clear_bit(FLG_FILLEMPTY, &bch->Flags);
 180                 }
 181                 break;
 182         case MISDN_CTRL_RX_OFF:
 183                 /* read back dropped byte count */
 184                 cq->p2 = bch->dropcnt;
 185                 if (cq->p1)
 186                         test_and_set_bit(FLG_RX_OFF, &bch->Flags);
 187                 else
 188                         test_and_clear_bit(FLG_RX_OFF, &bch->Flags);
 189                 bch->dropcnt = 0;
 190                 break;
 191         case MISDN_CTRL_RX_BUFFER:
 192                 if (cq->p2 > MISDN_CTRL_RX_SIZE_IGNORE)
 193                         bch->next_maxlen = cq->p2;
 194                 if (cq->p1 > MISDN_CTRL_RX_SIZE_IGNORE)
 195                         bch->next_minlen = cq->p1;
 196                 /* we return the old values */
 197                 cq->p1 = bch->minlen;
 198                 cq->p2 = bch->maxlen;
 199                 break;
 200         default:
 201                 pr_info("mISDN unhandled control %x operation\n", cq->op);
 202                 ret = -EINVAL;
 203                 break;
 204         }
 205         return ret;
 206 }
 207 EXPORT_SYMBOL(mISDN_ctrl_bchannel);
 208
 209 static inline u_int
 210 get_sapi_tei(u_char *p)
 211 {
 212         u_int   sapi, tei;
 213
 214         sapi = *p >> 2;
 215         tei = p[1] >> 1;
 216         return sapi | (tei << 8);
 217 }
 218
 219 void
 220 recv_Dchannel(struct dchannel *dch)
 221 {
 222         struct mISDNhead *hh;
 223
 224         if (dch->rx_skb->len < 2) { /* at least 2 for sapi / tei */
 225                 dev_kfree_skb(dch->rx_skb);
 226                 dch->rx_skb = NULL;
 227                 return;
 228         }
 229         hh = mISDN_HEAD_P(dch->rx_skb);
 230         hh->prim = PH_DATA_IND;
 231         hh->id = get_sapi_tei(dch->rx_skb->data);
 232         skb_queue_tail(&dch->rqueue, dch->rx_skb);
 233         dch->rx_skb = NULL;
 234         schedule_event(dch, FLG_RECVQUEUE);
 235 }
 236 EXPORT_SYMBOL(recv_Dchannel);
 237
 238 void
 239 recv_Echannel(struct dchannel *ech, struct dchannel *dch)
 240 {
 241         struct mISDNhead *hh;
 242
 243         if (ech->rx_skb->len < 2) { /* at least 2 for sapi / tei */
 244                 dev_kfree_skb(ech->rx_skb);
 245                 ech->rx_skb = NULL;
 246                 return;
 247         }
 248         hh = mISDN_HEAD_P(ech->rx_skb);
 249         hh->prim = PH_DATA_E_IND;
 250         hh->id = get_sapi_tei(ech->rx_skb->data);
 251         skb_queue_tail(&dch->rqueue, ech->rx_skb);
 252         ech->rx_skb = NULL;
 253         schedule_event(dch, FLG_RECVQUEUE);
 254 }
 255 EXPORT_SYMBOL(recv_Echannel);
 256
 257 void
 258 recv_Bchannel(struct bchannel *bch, unsigned int id, bool force)
 259 {
 260         struct mISDNhead *hh;
 261
 262         /* if allocation did fail upper functions still may call us */
 263         if (unlikely(!bch->rx_skb))
 264                 return;
 265         if (unlikely(!bch->rx_skb->len)) {
 266                 /* we have no data to send - this may happen after recovery
 267                  * from overflow or too small allocation.
 268                  * We need to free the buffer here */
 269                 dev_kfree_skb(bch->rx_skb);
 270                 bch->rx_skb = NULL;
 271         } else {
 272                 if (test_bit(FLG_TRANSPARENT, &bch->Flags) &&
 273                     (bch->rx_skb->len < bch->minlen) && !force)
 274                                 return;
 275                 hh = mISDN_HEAD_P(bch->rx_skb);
 276                 hh->prim = PH_DATA_IND;
 277                 hh->id = id;
 278                 if (bch->rcount >= 64) {
 279                         printk(KERN_WARNING
 280                                "B%d receive queue overflow - flushing!\n",
 281                                bch->nr);
 282                         skb_queue_purge(&bch->rqueue);
 283                 }
 284                 bch->rcount++;
 285                 skb_queue_tail(&bch->rqueue, bch->rx_skb);
 286                 bch->rx_skb = NULL;
 287                 schedule_event(bch, FLG_RECVQUEUE);
 288         }
 289 }
 290 EXPORT_SYMBOL(recv_Bchannel);
 291
 292 void
 293 recv_Dchannel_skb(struct dchannel *dch, struct sk_buff *skb)
 294 {
 295         skb_queue_tail(&dch->rqueue, skb);
 296         schedule_event(dch, FLG_RECVQUEUE);
 297 }
 298 EXPORT_SYMBOL(recv_Dchannel_skb);
 299
 300 void
 301 recv_Bchannel_skb(struct bchannel *bch, struct sk_buff *skb)
 302 {
 303         if (bch->rcount >= 64) {
 304                 printk(KERN_WARNING "B-channel %p receive queue overflow, "
 305                        "flushing!\n", bch);
 306                 skb_queue_purge(&bch->rqueue);
 307                 bch->rcount = 0;
 308         }
 309         bch->rcount++;
 310         skb_queue_tail(&bch->rqueue, skb);
 311         schedule_event(bch, FLG_RECVQUEUE);
 312 }
 313 EXPORT_SYMBOL(recv_Bchannel_skb);
 314
 315 static void
 316 confirm_Dsend(struct dchannel *dch)
 317 {
 318         struct sk_buff  *skb;
 319
 320         skb = _alloc_mISDN_skb(PH_DATA_CNF, mISDN_HEAD_ID(dch->tx_skb),
 321                                0, NULL, GFP_ATOMIC);
 322         if (!skb) {
 323                 printk(KERN_ERR "%s: no skb id %x\n", __func__,
 324                        mISDN_HEAD_ID(dch->tx_skb));
 325                 return;
 326         }
 327         skb_queue_tail(&dch->rqueue, skb);
 328         schedule_event(dch, FLG_RECVQUEUE);
 329 }
 330
 331 int
 332 get_next_dframe(struct dchannel *dch)
 333 {
 334         dch->tx_idx = 0;
 335         dch->tx_skb = skb_dequeue(&dch->squeue);
 336         if (dch->tx_skb) {
 337                 confirm_Dsend(dch);
 338                 return 1;
 339         }
 340         dch->tx_skb = NULL;
 341         test_and_clear_bit(FLG_TX_BUSY, &dch->Flags);
 342         return 0;
 343 }
 344 EXPORT_SYMBOL(get_next_dframe);
 345
 346 static void
 347 confirm_Bsend(struct bchannel *bch)
 348 {
 349         struct sk_buff  *skb;
 350
 351         if (bch->rcount >= 64) {
 352                 printk(KERN_WARNING "B-channel %p receive queue overflow, "
 353                        "flushing!\n", bch);
 354                 skb_queue_purge(&bch->rqueue);
 355                 bch->rcount = 0;
 356         }
 357         skb = _alloc_mISDN_skb(PH_DATA_CNF, mISDN_HEAD_ID(bch->tx_skb),
 358                                0, NULL, GFP_ATOMIC);
 359         if (!skb) {
 360                 printk(KERN_ERR "%s: no skb id %x\n", __func__,
 361                        mISDN_HEAD_ID(bch->tx_skb));
 362                 return;
 363         }
 364         bch->rcount++;
 365         skb_queue_tail(&bch->rqueue, skb);
 366         schedule_event(bch, FLG_RECVQUEUE);
 367 }
 368
 369 int
 370 get_next_bframe(struct bchannel *bch)
 371 {
 372         bch->tx_idx = 0;
 373         if (test_bit(FLG_TX_NEXT, &bch->Flags)) {
 374                 bch->tx_skb = bch->next_skb;
 375                 if (bch->tx_skb) {
 376                         bch->next_skb = NULL;
 377                         test_and_clear_bit(FLG_TX_NEXT, &bch->Flags);
 378                         /* confirm imediately to allow next data */
 379                         confirm_Bsend(bch);
 380                         return 1;
 381                 } else {
 382                         test_and_clear_bit(FLG_TX_NEXT, &bch->Flags);
 383                         printk(KERN_WARNING "B TX_NEXT without skb\n");
 384                 }
 385         }
 386         bch->tx_skb = NULL;
 387         test_and_clear_bit(FLG_TX_BUSY, &bch->Flags);
 388         return 0;
 389 }
 390 EXPORT_SYMBOL(get_next_bframe);
 391
 392 void
 393 queue_ch_frame(struct mISDNchannel *ch, u_int pr, int id, struct sk_buff *skb)
 394 {
 395         struct mISDNhead *hh;
 396
 397         if (!skb) {
 398                 _queue_data(ch, pr, id, 0, NULL, GFP_ATOMIC);
 399         } else {
 400                 if (ch->peer) {
 401                         hh = mISDN_HEAD_P(skb);
 402                         hh->prim = pr;
 403                         hh->id = id;
 404                         if (!ch->recv(ch->peer, skb))
 405                                 return;
 406                 }
 407                 dev_kfree_skb(skb);
 408         }
 409 }
 410 EXPORT_SYMBOL(queue_ch_frame);
 411
 412 int
 413 dchannel_senddata(struct dchannel *ch, struct sk_buff *skb)
 414 {
 415         /* check oversize */
 416         if (skb->len <= 0) {
 417                 printk(KERN_WARNING "%s: skb too small\n", __func__);
 418                 return -EINVAL;
 419         }
 420         if (skb->len > ch->maxlen) {
 421                 printk(KERN_WARNING "%s: skb too large(%d/%d)\n",
 422                        __func__, skb->len, ch->maxlen);
 423                 return -EINVAL;
 424         }
 425         /* HW lock must be obtained */
 426         if (test_and_set_bit(FLG_TX_BUSY, &ch->Flags)) {
 427                 skb_queue_tail(&ch->squeue, skb);
 428                 return 0;
 429         } else {
 430                 /* write to fifo */
 431                 ch->tx_skb = skb;
 432                 ch->tx_idx = 0;
 433                 return 1;
 434         }
 435 }
 436 EXPORT_SYMBOL(dchannel_senddata);
 437
 438 int
 439 bchannel_senddata(struct bchannel *ch, struct sk_buff *skb)
 440 {
 441
 442         /* check oversize */
 443         if (skb->len <= 0) {
 444                 printk(KERN_WARNING "%s: skb too small\n", __func__);
 445                 return -EINVAL;
 446         }
 447         if (skb->len > ch->maxlen) {
 448                 printk(KERN_WARNING "%s: skb too large(%d/%d)\n",
 449                        __func__, skb->len, ch->maxlen);
 450                 return -EINVAL;
 451         }
 452         /* HW lock must be obtained */
 453         /* check for pending next_skb */
 454         if (ch->next_skb) {
 455                 printk(KERN_WARNING
 456                        "%s: next_skb exist ERROR (skb->len=%d next_skb->len=%d)\n",
 457                        __func__, skb->len, ch->next_skb->len);
 458                 return -EBUSY;
 459         }
 460         if (test_and_set_bit(FLG_TX_BUSY, &ch->Flags)) {
 461                 test_and_set_bit(FLG_TX_NEXT, &ch->Flags);
 462                 ch->next_skb = skb;
 463                 return 0;
 464         } else {
 465                 /* write to fifo */
 466                 ch->tx_skb = skb;
 467                 ch->tx_idx = 0;
 468                 confirm_Bsend(ch);
 469                 return 1;
 470         }
 471 }
 472 EXPORT_SYMBOL(bchannel_senddata);
 473
 474 /* The function allocates a new receive skb on demand with a size for the
 475  * requirements of the current protocol. It returns the tailroom of the
 476  * receive skb or an error.
 477  */
 478 int
 479 bchannel_get_rxbuf(struct bchannel *bch, int reqlen)
 480 {
 481         int len;
 482
 483         if (bch->rx_skb) {
 484                 len = skb_tailroom(bch->rx_skb);
 485                 if (len < reqlen) {
 486                         pr_warning("B%d no space for %d (only %d) bytes\n",
 487                                    bch->nr, reqlen, len);
 488                         if (test_bit(FLG_TRANSPARENT, &bch->Flags)) {
 489                                 /* send what we have now and try a new buffer */
 490                                 recv_Bchannel(bch, 0, true);
 491                         } else {
 492                                 /* on HDLC we have to drop too big frames */
 493                                 return -EMSGSIZE;
 494                         }
 495                 } else {
 496                         return len;
 497                 }
 498         }
 499         /* update current min/max length first */
 500         if (unlikely(bch->maxlen != bch->next_maxlen))
 501                 bch->maxlen = bch->next_maxlen;
 502         if (unlikely(bch->minlen != bch->next_minlen))
 503                 bch->minlen = bch->next_minlen;
 504         if (unlikely(reqlen > bch->maxlen))
 505                 return -EMSGSIZE;
 506         if (test_bit(FLG_TRANSPARENT, &bch->Flags)) {
 507                 if (reqlen >= bch->minlen) {
 508                         len = reqlen;
 509                 } else {
 510                         len = 2 * bch->minlen;
 511                         if (len > bch->maxlen)
 512                                 len = bch->maxlen;
 513                 }
 514         } else {
 515                 /* with HDLC we do not know the length yet */
 516                 len = bch->maxlen;
 517         }
 518         bch->rx_skb = mI_alloc_skb(len, GFP_ATOMIC);
 519         if (!bch->rx_skb) {
 520                 pr_warning("B%d receive no memory for %d bytes\n",
 521                            bch->nr, len);
 522                 len = -ENOMEM;
 523         }
 524         return len;
 525 }
 526 EXPORT_SYMBOL(bchannel_get_rxbuf);