linux/drivers/isdn/mISDN/hwchannel.c
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   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
  22static void
  23dchannel_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
  45static void
  46bchannel_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
  65int
  66mISDN_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}
  81EXPORT_SYMBOL(mISDN_initdchannel);
  82
  83int
  84mISDN_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}
 104EXPORT_SYMBOL(mISDN_initbchannel);
 105
 106int
 107mISDN_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}
 122EXPORT_SYMBOL(mISDN_freedchannel);
 123
 124void
 125mISDN_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}
 154EXPORT_SYMBOL(mISDN_clear_bchannel);
 155
 156void
 157mISDN_freebchannel(struct bchannel *ch)
 158{
 159        cancel_work_sync(&ch->workq);
 160        mISDN_clear_bchannel(ch);
 161}
 162EXPORT_SYMBOL(mISDN_freebchannel);
 163
 164int
 165mISDN_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}
 207EXPORT_SYMBOL(mISDN_ctrl_bchannel);
 208
 209static inline u_int
 210get_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
 219void
 220recv_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}
 236EXPORT_SYMBOL(recv_Dchannel);
 237
 238void
 239recv_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}
 255EXPORT_SYMBOL(recv_Echannel);
 256
 257void
 258recv_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}
 290EXPORT_SYMBOL(recv_Bchannel);
 291
 292void
 293recv_Dchannel_skb(struct dchannel *dch, struct sk_buff *skb)
 294{
 295        skb_queue_tail(&dch->rqueue, skb);
 296        schedule_event(dch, FLG_RECVQUEUE);
 297}
 298EXPORT_SYMBOL(recv_Dchannel_skb);
 299
 300void
 301recv_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}
 313EXPORT_SYMBOL(recv_Bchannel_skb);
 314
 315static void
 316confirm_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
 331int
 332get_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}
 344EXPORT_SYMBOL(get_next_dframe);
 345
 346static void
 347confirm_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
 369int
 370get_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}
 390EXPORT_SYMBOL(get_next_bframe);
 391
 392void
 393queue_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}
 410EXPORT_SYMBOL(queue_ch_frame);
 411
 412int
 413dchannel_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}
 436EXPORT_SYMBOL(dchannel_senddata);
 437
 438int
 439bchannel_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}
 472EXPORT_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 */
 478int
 479bchannel_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}
 526EXPORT_SYMBOL(bchannel_get_rxbuf);
 527