drivers/isdn/mISDN/hwchannel.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *
   4  * Author       Karsten Keil <kkeil@novell.com>
   5  *
   6  * Copyright 2008  by Karsten Keil <kkeil@novell.com>
   7  */
   8
   9 #include <linux/gfp.h>
  10 #include <linux/module.h>
  11 #include <linux/mISDNhw.h>
  12
  13 static void
  14 dchannel_bh(struct work_struct *ws)
  15 {
  16         struct dchannel *dch  = container_of(ws, struct dchannel, workq);
  17         struct sk_buff  *skb;
  18         int             err;
  19
  20         if (test_and_clear_bit(FLG_RECVQUEUE, &dch->Flags)) {
  21                 while ((skb = skb_dequeue(&dch->rqueue))) {
  22                         if (likely(dch->dev.D.peer)) {
  23                                 err = dch->dev.D.recv(dch->dev.D.peer, skb);
  24                                 if (err)
  25                                         dev_kfree_skb(skb);
  26                         } else
  27                                 dev_kfree_skb(skb);
  28                 }
  29         }
  30         if (test_and_clear_bit(FLG_PHCHANGE, &dch->Flags)) {
  31                 if (dch->phfunc)
  32                         dch->phfunc(dch);
  33         }
  34 }
  35
  36 static void
  37 bchannel_bh(struct work_struct *ws)
  38 {
  39         struct bchannel *bch  = container_of(ws, struct bchannel, workq);
  40         struct sk_buff  *skb;
  41         int             err;
  42
  43         if (test_and_clear_bit(FLG_RECVQUEUE, &bch->Flags)) {
  44                 while ((skb = skb_dequeue(&bch->rqueue))) {
  45                         bch->rcount--;
  46                         if (likely(bch->ch.peer)) {
  47                                 err = bch->ch.recv(bch->ch.peer, skb);
  48                                 if (err)
  49                                         dev_kfree_skb(skb);
  50                         } else
  51                                 dev_kfree_skb(skb);
  52                 }
  53         }
  54 }
  55
  56 int
  57 mISDN_initdchannel(struct dchannel *ch, int maxlen, void *phf)
  58 {
  59         test_and_set_bit(FLG_HDLC, &ch->Flags);
  60         ch->maxlen = maxlen;
  61         ch->hw = NULL;
  62         ch->rx_skb = NULL;
  63         ch->tx_skb = NULL;
  64         ch->tx_idx = 0;
  65         ch->phfunc = phf;
  66         skb_queue_head_init(&ch->squeue);
  67         skb_queue_head_init(&ch->rqueue);
  68         INIT_LIST_HEAD(&ch->dev.bchannels);
  69         INIT_WORK(&ch->workq, dchannel_bh);
  70         return 0;
  71 }
  72 EXPORT_SYMBOL(mISDN_initdchannel);
  73
  74 int
  75 mISDN_initbchannel(struct bchannel *ch, unsigned short maxlen,
  76                    unsigned short minlen)
  77 {
  78         ch->Flags = 0;
  79         ch->minlen = minlen;
  80         ch->next_minlen = minlen;
  81         ch->init_minlen = minlen;
  82         ch->maxlen = maxlen;
  83         ch->next_maxlen = maxlen;
  84         ch->init_maxlen = maxlen;
  85         ch->hw = NULL;
  86         ch->rx_skb = NULL;
  87         ch->tx_skb = NULL;
  88         ch->tx_idx = 0;
  89         skb_queue_head_init(&ch->rqueue);
  90         ch->rcount = 0;
  91         ch->next_skb = NULL;
  92         INIT_WORK(&ch->workq, bchannel_bh);
  93         return 0;
  94 }
  95 EXPORT_SYMBOL(mISDN_initbchannel);
  96
  97 int
  98 mISDN_freedchannel(struct dchannel *ch)
  99 {
 100         if (ch->tx_skb) {
 101                 dev_kfree_skb(ch->tx_skb);
 102                 ch->tx_skb = NULL;
 103         }
 104         if (ch->rx_skb) {
 105                 dev_kfree_skb(ch->rx_skb);
 106                 ch->rx_skb = NULL;
 107         }
 108         skb_queue_purge(&ch->squeue);
 109         skb_queue_purge(&ch->rqueue);
 110         flush_work(&ch->workq);
 111         return 0;
 112 }
 113 EXPORT_SYMBOL(mISDN_freedchannel);
 114
 115 void
 116 mISDN_clear_bchannel(struct bchannel *ch)
 117 {
 118         if (ch->tx_skb) {
 119                 dev_kfree_skb(ch->tx_skb);
 120                 ch->tx_skb = NULL;
 121         }
 122         ch->tx_idx = 0;
 123         if (ch->rx_skb) {
 124                 dev_kfree_skb(ch->rx_skb);
 125                 ch->rx_skb = NULL;
 126         }
 127         if (ch->next_skb) {
 128                 dev_kfree_skb(ch->next_skb);
 129                 ch->next_skb = NULL;
 130         }
 131         test_and_clear_bit(FLG_TX_BUSY, &ch->Flags);
 132         test_and_clear_bit(FLG_TX_NEXT, &ch->Flags);
 133         test_and_clear_bit(FLG_ACTIVE, &ch->Flags);
 134         test_and_clear_bit(FLG_FILLEMPTY, &ch->Flags);
 135         test_and_clear_bit(FLG_TX_EMPTY, &ch->Flags);
 136         test_and_clear_bit(FLG_RX_OFF, &ch->Flags);
 137         ch->dropcnt = 0;
 138         ch->minlen = ch->init_minlen;
 139         ch->next_minlen = ch->init_minlen;
 140         ch->maxlen = ch->init_maxlen;
 141         ch->next_maxlen = ch->init_maxlen;
 142         skb_queue_purge(&ch->rqueue);
 143         ch->rcount = 0;
 144 }
 145 EXPORT_SYMBOL(mISDN_clear_bchannel);
 146
 147 void
 148 mISDN_freebchannel(struct bchannel *ch)
 149 {
 150         cancel_work_sync(&ch->workq);
 151         mISDN_clear_bchannel(ch);
 152 }
 153 EXPORT_SYMBOL(mISDN_freebchannel);
 154
 155 int
 156 mISDN_ctrl_bchannel(struct bchannel *bch, struct mISDN_ctrl_req *cq)
 157 {
 158         int ret = 0;
 159
 160         switch (cq->op) {
 161         case MISDN_CTRL_GETOP:
 162                 cq->op = MISDN_CTRL_RX_BUFFER | MISDN_CTRL_FILL_EMPTY |
 163                          MISDN_CTRL_RX_OFF;
 164                 break;
 165         case MISDN_CTRL_FILL_EMPTY:
 166                 if (cq->p1) {
 167                         memset(bch->fill, cq->p2 & 0xff, MISDN_BCH_FILL_SIZE);
 168                         test_and_set_bit(FLG_FILLEMPTY, &bch->Flags);
 169                 } else {
 170                         test_and_clear_bit(FLG_FILLEMPTY, &bch->Flags);
 171                 }
 172                 break;
 173         case MISDN_CTRL_RX_OFF:
 174                 /* read back dropped byte count */
 175                 cq->p2 = bch->dropcnt;
 176                 if (cq->p1)
 177                         test_and_set_bit(FLG_RX_OFF, &bch->Flags);
 178                 else
 179                         test_and_clear_bit(FLG_RX_OFF, &bch->Flags);
 180                 bch->dropcnt = 0;
 181                 break;
 182         case MISDN_CTRL_RX_BUFFER:
 183                 if (cq->p2 > MISDN_CTRL_RX_SIZE_IGNORE)
 184                         bch->next_maxlen = cq->p2;
 185                 if (cq->p1 > MISDN_CTRL_RX_SIZE_IGNORE)
 186                         bch->next_minlen = cq->p1;
 187                 /* we return the old values */
 188                 cq->p1 = bch->minlen;
 189                 cq->p2 = bch->maxlen;
 190                 break;
 191         default:
 192                 pr_info("mISDN unhandled control %x operation\n", cq->op);
 193                 ret = -EINVAL;
 194                 break;
 195         }
 196         return ret;
 197 }
 198 EXPORT_SYMBOL(mISDN_ctrl_bchannel);
 199
 200 static inline u_int
 201 get_sapi_tei(u_char *p)
 202 {
 203         u_int   sapi, tei;
 204
 205         sapi = *p >> 2;
 206         tei = p[1] >> 1;
 207         return sapi | (tei << 8);
 208 }
 209
 210 void
 211 recv_Dchannel(struct dchannel *dch)
 212 {
 213         struct mISDNhead *hh;
 214
 215         if (dch->rx_skb->len < 2) { /* at least 2 for sapi / tei */
 216                 dev_kfree_skb(dch->rx_skb);
 217                 dch->rx_skb = NULL;
 218                 return;
 219         }
 220         hh = mISDN_HEAD_P(dch->rx_skb);
 221         hh->prim = PH_DATA_IND;
 222         hh->id = get_sapi_tei(dch->rx_skb->data);
 223         skb_queue_tail(&dch->rqueue, dch->rx_skb);
 224         dch->rx_skb = NULL;
 225         schedule_event(dch, FLG_RECVQUEUE);
 226 }
 227 EXPORT_SYMBOL(recv_Dchannel);
 228
 229 void
 230 recv_Echannel(struct dchannel *ech, struct dchannel *dch)
 231 {
 232         struct mISDNhead *hh;
 233
 234         if (ech->rx_skb->len < 2) { /* at least 2 for sapi / tei */
 235                 dev_kfree_skb(ech->rx_skb);
 236                 ech->rx_skb = NULL;
 237                 return;
 238         }
 239         hh = mISDN_HEAD_P(ech->rx_skb);
 240         hh->prim = PH_DATA_E_IND;
 241         hh->id = get_sapi_tei(ech->rx_skb->data);
 242         skb_queue_tail(&dch->rqueue, ech->rx_skb);
 243         ech->rx_skb = NULL;
 244         schedule_event(dch, FLG_RECVQUEUE);
 245 }
 246 EXPORT_SYMBOL(recv_Echannel);
 247
 248 void
 249 recv_Bchannel(struct bchannel *bch, unsigned int id, bool force)
 250 {
 251         struct mISDNhead *hh;
 252
 253         /* if allocation did fail upper functions still may call us */
 254         if (unlikely(!bch->rx_skb))
 255                 return;
 256         if (unlikely(!bch->rx_skb->len)) {
 257                 /* we have no data to send - this may happen after recovery
 258                  * from overflow or too small allocation.
 259                  * We need to free the buffer here */
 260                 dev_kfree_skb(bch->rx_skb);
 261                 bch->rx_skb = NULL;
 262         } else {
 263                 if (test_bit(FLG_TRANSPARENT, &bch->Flags) &&
 264                     (bch->rx_skb->len < bch->minlen) && !force)
 265                                 return;
 266                 hh = mISDN_HEAD_P(bch->rx_skb);
 267                 hh->prim = PH_DATA_IND;
 268                 hh->id = id;
 269                 if (bch->rcount >= 64) {
 270                         printk(KERN_WARNING
 271                                "B%d receive queue overflow - flushing!\n",
 272                                bch->nr);
 273                         skb_queue_purge(&bch->rqueue);
 274                 }
 275                 bch->rcount++;
 276                 skb_queue_tail(&bch->rqueue, bch->rx_skb);
 277                 bch->rx_skb = NULL;
 278                 schedule_event(bch, FLG_RECVQUEUE);
 279         }
 280 }
 281 EXPORT_SYMBOL(recv_Bchannel);
 282
 283 void
 284 recv_Dchannel_skb(struct dchannel *dch, struct sk_buff *skb)
 285 {
 286         skb_queue_tail(&dch->rqueue, skb);
 287         schedule_event(dch, FLG_RECVQUEUE);
 288 }
 289 EXPORT_SYMBOL(recv_Dchannel_skb);
 290
 291 void
 292 recv_Bchannel_skb(struct bchannel *bch, struct sk_buff *skb)
 293 {
 294         if (bch->rcount >= 64) {
 295                 printk(KERN_WARNING "B-channel %p receive queue overflow, "
 296                        "flushing!\n", bch);
 297                 skb_queue_purge(&bch->rqueue);
 298                 bch->rcount = 0;
 299         }
 300         bch->rcount++;
 301         skb_queue_tail(&bch->rqueue, skb);
 302         schedule_event(bch, FLG_RECVQUEUE);
 303 }
 304 EXPORT_SYMBOL(recv_Bchannel_skb);
 305
 306 static void
 307 confirm_Dsend(struct dchannel *dch)
 308 {
 309         struct sk_buff  *skb;
 310
 311         skb = _alloc_mISDN_skb(PH_DATA_CNF, mISDN_HEAD_ID(dch->tx_skb),
 312                                0, NULL, GFP_ATOMIC);
 313         if (!skb) {
 314                 printk(KERN_ERR "%s: no skb id %x\n", __func__,
 315                        mISDN_HEAD_ID(dch->tx_skb));
 316                 return;
 317         }
 318         skb_queue_tail(&dch->rqueue, skb);
 319         schedule_event(dch, FLG_RECVQUEUE);
 320 }
 321
 322 int
 323 get_next_dframe(struct dchannel *dch)
 324 {
 325         dch->tx_idx = 0;
 326         dch->tx_skb = skb_dequeue(&dch->squeue);
 327         if (dch->tx_skb) {
 328                 confirm_Dsend(dch);
 329                 return 1;
 330         }
 331         dch->tx_skb = NULL;
 332         test_and_clear_bit(FLG_TX_BUSY, &dch->Flags);
 333         return 0;
 334 }
 335 EXPORT_SYMBOL(get_next_dframe);
 336
 337 static void
 338 confirm_Bsend(struct bchannel *bch)
 339 {
 340         struct sk_buff  *skb;
 341
 342         if (bch->rcount >= 64) {
 343                 printk(KERN_WARNING "B-channel %p receive queue overflow, "
 344                        "flushing!\n", bch);
 345                 skb_queue_purge(&bch->rqueue);
 346                 bch->rcount = 0;
 347         }
 348         skb = _alloc_mISDN_skb(PH_DATA_CNF, mISDN_HEAD_ID(bch->tx_skb),
 349                                0, NULL, GFP_ATOMIC);
 350         if (!skb) {
 351                 printk(KERN_ERR "%s: no skb id %x\n", __func__,
 352                        mISDN_HEAD_ID(bch->tx_skb));
 353                 return;
 354         }
 355         bch->rcount++;
 356         skb_queue_tail(&bch->rqueue, skb);
 357         schedule_event(bch, FLG_RECVQUEUE);
 358 }
 359
 360 int
 361 get_next_bframe(struct bchannel *bch)
 362 {
 363         bch->tx_idx = 0;
 364         if (test_bit(FLG_TX_NEXT, &bch->Flags)) {
 365                 bch->tx_skb = bch->next_skb;
 366                 if (bch->tx_skb) {
 367                         bch->next_skb = NULL;
 368                         test_and_clear_bit(FLG_TX_NEXT, &bch->Flags);
 369                         /* confirm imediately to allow next data */
 370                         confirm_Bsend(bch);
 371                         return 1;
 372                 } else {
 373                         test_and_clear_bit(FLG_TX_NEXT, &bch->Flags);
 374                         printk(KERN_WARNING "B TX_NEXT without skb\n");
 375                 }
 376         }
 377         bch->tx_skb = NULL;
 378         test_and_clear_bit(FLG_TX_BUSY, &bch->Flags);
 379         return 0;
 380 }
 381 EXPORT_SYMBOL(get_next_bframe);
 382
 383 void
 384 queue_ch_frame(struct mISDNchannel *ch, u_int pr, int id, struct sk_buff *skb)
 385 {
 386         struct mISDNhead *hh;
 387
 388         if (!skb) {
 389                 _queue_data(ch, pr, id, 0, NULL, GFP_ATOMIC);
 390         } else {
 391                 if (ch->peer) {
 392                         hh = mISDN_HEAD_P(skb);
 393                         hh->prim = pr;
 394                         hh->id = id;
 395                         if (!ch->recv(ch->peer, skb))
 396                                 return;
 397                 }
 398                 dev_kfree_skb(skb);
 399         }
 400 }
 401 EXPORT_SYMBOL(queue_ch_frame);
 402
 403 int
 404 dchannel_senddata(struct dchannel *ch, struct sk_buff *skb)
 405 {
 406         /* check oversize */
 407         if (skb->len <= 0) {
 408                 printk(KERN_WARNING "%s: skb too small\n", __func__);
 409                 return -EINVAL;
 410         }
 411         if (skb->len > ch->maxlen) {
 412                 printk(KERN_WARNING "%s: skb too large(%d/%d)\n",
 413                        __func__, skb->len, ch->maxlen);
 414                 return -EINVAL;
 415         }
 416         /* HW lock must be obtained */
 417         if (test_and_set_bit(FLG_TX_BUSY, &ch->Flags)) {
 418                 skb_queue_tail(&ch->squeue, skb);
 419                 return 0;
 420         } else {
 421                 /* write to fifo */
 422                 ch->tx_skb = skb;
 423                 ch->tx_idx = 0;
 424                 return 1;
 425         }
 426 }
 427 EXPORT_SYMBOL(dchannel_senddata);
 428
 429 int
 430 bchannel_senddata(struct bchannel *ch, struct sk_buff *skb)
 431 {
 432
 433         /* check oversize */
 434         if (skb->len <= 0) {
 435                 printk(KERN_WARNING "%s: skb too small\n", __func__);
 436                 return -EINVAL;
 437         }
 438         if (skb->len > ch->maxlen) {
 439                 printk(KERN_WARNING "%s: skb too large(%d/%d)\n",
 440                        __func__, skb->len, ch->maxlen);
 441                 return -EINVAL;
 442         }
 443         /* HW lock must be obtained */
 444         /* check for pending next_skb */
 445         if (ch->next_skb) {
 446                 printk(KERN_WARNING
 447                        "%s: next_skb exist ERROR (skb->len=%d next_skb->len=%d)\n",
 448                        __func__, skb->len, ch->next_skb->len);
 449                 return -EBUSY;
 450         }
 451         if (test_and_set_bit(FLG_TX_BUSY, &ch->Flags)) {
 452                 test_and_set_bit(FLG_TX_NEXT, &ch->Flags);
 453                 ch->next_skb = skb;
 454                 return 0;
 455         } else {
 456                 /* write to fifo */
 457                 ch->tx_skb = skb;
 458                 ch->tx_idx = 0;
 459                 confirm_Bsend(ch);
 460                 return 1;
 461         }
 462 }
 463 EXPORT_SYMBOL(bchannel_senddata);
 464
 465 /* The function allocates a new receive skb on demand with a size for the
 466  * requirements of the current protocol. It returns the tailroom of the
 467  * receive skb or an error.
 468  */
 469 int
 470 bchannel_get_rxbuf(struct bchannel *bch, int reqlen)
 471 {
 472         int len;
 473
 474         if (bch->rx_skb) {
 475                 len = skb_tailroom(bch->rx_skb);
 476                 if (len < reqlen) {
 477                         pr_warning("B%d no space for %d (only %d) bytes\n",
 478                                    bch->nr, reqlen, len);
 479                         if (test_bit(FLG_TRANSPARENT, &bch->Flags)) {
 480                                 /* send what we have now and try a new buffer */
 481                                 recv_Bchannel(bch, 0, true);
 482                         } else {
 483                                 /* on HDLC we have to drop too big frames */
 484                                 return -EMSGSIZE;
 485                         }
 486                 } else {
 487                         return len;
 488                 }
 489         }
 490         /* update current min/max length first */
 491         if (unlikely(bch->maxlen != bch->next_maxlen))
 492                 bch->maxlen = bch->next_maxlen;
 493         if (unlikely(bch->minlen != bch->next_minlen))
 494                 bch->minlen = bch->next_minlen;
 495         if (unlikely(reqlen > bch->maxlen))
 496                 return -EMSGSIZE;
 497         if (test_bit(FLG_TRANSPARENT, &bch->Flags)) {
 498                 if (reqlen >= bch->minlen) {
 499                         len = reqlen;
 500                 } else {
 501                         len = 2 * bch->minlen;
 502                         if (len > bch->maxlen)
 503                                 len = bch->maxlen;
 504                 }
 505         } else {
 506                 /* with HDLC we do not know the length yet */
 507                 len = bch->maxlen;
 508         }
 509         bch->rx_skb = mI_alloc_skb(len, GFP_ATOMIC);
 510         if (!bch->rx_skb) {
 511                 pr_warning("B%d receive no memory for %d bytes\n",
 512                            bch->nr, len);
 513                 len = -ENOMEM;
 514         }
 515         return len;
 516 }
 517 EXPORT_SYMBOL(bchannel_get_rxbuf);