net/caif/cfctrl.c

   1 /*
   2  * Copyright (C) ST-Ericsson AB 2010
   3  * Author:      Sjur Brendeland/sjur.brandeland@stericsson.com
   4  * License terms: GNU General Public License (GPL) version 2
   5  */
   6
   7 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
   8
   9 #include <linux/stddef.h>
  10 #include <linux/spinlock.h>
  11 #include <linux/slab.h>
  12 #include <net/caif/caif_layer.h>
  13 #include <net/caif/cfpkt.h>
  14 #include <net/caif/cfctrl.h>
  15
  16 #define container_obj(layr) container_of(layr, struct cfctrl, serv.layer)
  17 #define UTILITY_NAME_LENGTH 16
  18 #define CFPKT_CTRL_PKT_LEN 20
  19
  20 #ifdef CAIF_NO_LOOP
  21 static int handle_loop(struct cfctrl *ctrl,
  22                               int cmd, struct cfpkt *pkt){
  23         return -1;
  24 }
  25 #else
  26 static int handle_loop(struct cfctrl *ctrl,
  27                 int cmd, struct cfpkt *pkt);
  28 #endif
  29 static int cfctrl_recv(struct cflayer *layr, struct cfpkt *pkt);
  30 static void cfctrl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
  31                            int phyid);
  32
  33
  34 struct cflayer *cfctrl_create(void)
  35 {
  36         struct dev_info dev_info;
  37         struct cfctrl *this =
  38                 kmalloc(sizeof(struct cfctrl), GFP_ATOMIC);
  39         if (!this) {
  40                 pr_warn("Out of memory\n");
  41                 return NULL;
  42         }
  43         caif_assert(offsetof(struct cfctrl, serv.layer) == 0);
  44         memset(&dev_info, 0, sizeof(dev_info));
  45         dev_info.id = 0xff;
  46         memset(this, 0, sizeof(*this));
  47         cfsrvl_init(&this->serv, 0, &dev_info, false);
  48         atomic_set(&this->req_seq_no, 1);
  49         atomic_set(&this->rsp_seq_no, 1);
  50         this->serv.layer.receive = cfctrl_recv;
  51         sprintf(this->serv.layer.name, "ctrl");
  52         this->serv.layer.ctrlcmd = cfctrl_ctrlcmd;
  53 #ifndef CAIF_NO_LOOP
  54         spin_lock_init(&this->loop_linkid_lock);
  55         this->loop_linkid = 1;
  56 #endif
  57         spin_lock_init(&this->info_list_lock);
  58         INIT_LIST_HEAD(&this->list);
  59         return &this->serv.layer;
  60 }
  61
  62 void cfctrl_remove(struct cflayer *layer)
  63 {
  64         struct cfctrl_request_info *p, *tmp;
  65         struct cfctrl *ctrl = container_obj(layer);
  66
  67         spin_lock_bh(&ctrl->info_list_lock);
  68         list_for_each_entry_safe(p, tmp, &ctrl->list, list) {
  69                 list_del(&p->list);
  70                 kfree(p);
  71         }
  72         spin_unlock_bh(&ctrl->info_list_lock);
  73         kfree(layer);
  74 }
  75
  76 static bool param_eq(const struct cfctrl_link_param *p1,
  77                         const struct cfctrl_link_param *p2)
  78 {
  79         bool eq =
  80             p1->linktype == p2->linktype &&
  81             p1->priority == p2->priority &&
  82             p1->phyid == p2->phyid &&
  83             p1->endpoint == p2->endpoint && p1->chtype == p2->chtype;
  84
  85         if (!eq)
  86                 return false;
  87
  88         switch (p1->linktype) {
  89         case CFCTRL_SRV_VEI:
  90                 return true;
  91         case CFCTRL_SRV_DATAGRAM:
  92                 return p1->u.datagram.connid == p2->u.datagram.connid;
  93         case CFCTRL_SRV_RFM:
  94                 return
  95                     p1->u.rfm.connid == p2->u.rfm.connid &&
  96                     strcmp(p1->u.rfm.volume, p2->u.rfm.volume) == 0;
  97         case CFCTRL_SRV_UTIL:
  98                 return
  99                     p1->u.utility.fifosize_kb == p2->u.utility.fifosize_kb
 100                     && p1->u.utility.fifosize_bufs ==
 101                     p2->u.utility.fifosize_bufs
 102                     && strcmp(p1->u.utility.name, p2->u.utility.name) == 0
 103                     && p1->u.utility.paramlen == p2->u.utility.paramlen
 104                     && memcmp(p1->u.utility.params, p2->u.utility.params,
 105                               p1->u.utility.paramlen) == 0;
 106
 107         case CFCTRL_SRV_VIDEO:
 108                 return p1->u.video.connid == p2->u.video.connid;
 109         case CFCTRL_SRV_DBG:
 110                 return true;
 111         case CFCTRL_SRV_DECM:
 112                 return false;
 113         default:
 114                 return false;
 115         }
 116         return false;
 117 }
 118
 119 static bool cfctrl_req_eq(const struct cfctrl_request_info *r1,
 120                           const struct cfctrl_request_info *r2)
 121 {
 122         if (r1->cmd != r2->cmd)
 123                 return false;
 124         if (r1->cmd == CFCTRL_CMD_LINK_SETUP)
 125                 return param_eq(&r1->param, &r2->param);
 126         else
 127                 return r1->channel_id == r2->channel_id;
 128 }
 129
 130 /* Insert request at the end */
 131 static void cfctrl_insert_req(struct cfctrl *ctrl,
 132                               struct cfctrl_request_info *req)
 133 {
 134         spin_lock_bh(&ctrl->info_list_lock);
 135         atomic_inc(&ctrl->req_seq_no);
 136         req->sequence_no = atomic_read(&ctrl->req_seq_no);
 137         list_add_tail(&req->list, &ctrl->list);
 138         spin_unlock_bh(&ctrl->info_list_lock);
 139 }
 140
 141 /* Compare and remove request */
 142 static struct cfctrl_request_info *cfctrl_remove_req(struct cfctrl *ctrl,
 143                                                 struct cfctrl_request_info *req)
 144 {
 145         struct cfctrl_request_info *p, *tmp, *first;
 146
 147         first = list_first_entry(&ctrl->list, struct cfctrl_request_info, list);
 148
 149         list_for_each_entry_safe(p, tmp, &ctrl->list, list) {
 150                 if (cfctrl_req_eq(req, p)) {
 151                         if (p != first)
 152                                 pr_warn("Requests are not received in order\n");
 153
 154                         atomic_set(&ctrl->rsp_seq_no,
 155                                          p->sequence_no);
 156                         list_del(&p->list);
 157                         goto out;
 158                 }
 159         }
 160         p = NULL;
 161 out:
 162         return p;
 163 }
 164
 165 struct cfctrl_rsp *cfctrl_get_respfuncs(struct cflayer *layer)
 166 {
 167         struct cfctrl *this = container_obj(layer);
 168         return &this->res;
 169 }
 170
 171 static void init_info(struct caif_payload_info *info, struct cfctrl *cfctrl)
 172 {
 173         info->hdr_len = 0;
 174         info->channel_id = cfctrl->serv.layer.id;
 175         info->dev_info = &cfctrl->serv.dev_info;
 176 }
 177
 178 void cfctrl_enum_req(struct cflayer *layer, u8 physlinkid)
 179 {
 180         struct cfctrl *cfctrl = container_obj(layer);
 181         int ret;
 182         struct cfpkt *pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
 183         if (!pkt) {
 184                 pr_warn("Out of memory\n");
 185                 return;
 186         }
 187         caif_assert(offsetof(struct cfctrl, serv.layer) == 0);
 188         init_info(cfpkt_info(pkt), cfctrl);
 189         cfpkt_info(pkt)->dev_info->id = physlinkid;
 190         cfctrl->serv.dev_info.id = physlinkid;
 191         cfpkt_addbdy(pkt, CFCTRL_CMD_ENUM);
 192         cfpkt_addbdy(pkt, physlinkid);
 193         ret =
 194             cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
 195 }
 196
 197 int cfctrl_linkup_request(struct cflayer *layer,
 198                            struct cfctrl_link_param *param,
 199                            struct cflayer *user_layer)
 200 {
 201         struct cfctrl *cfctrl = container_obj(layer);
 202         u32 tmp32;
 203         u16 tmp16;
 204         u8 tmp8;
 205         struct cfctrl_request_info *req;
 206         int ret;
 207         char utility_name[16];
 208         struct cfpkt *pkt;
 209
 210         if (cfctrl_cancel_req(layer, user_layer) > 0) {
 211                 /* Slight Paranoia, check if already connecting */
 212                 pr_err("Duplicate connect request for same client\n");
 213                 WARN_ON(1);
 214                 return -EALREADY;
 215         }
 216
 217         pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
 218         if (!pkt) {
 219                 pr_warn("Out of memory\n");
 220                 return -ENOMEM;
 221         }
 222         cfpkt_addbdy(pkt, CFCTRL_CMD_LINK_SETUP);
 223         cfpkt_addbdy(pkt, (param->chtype << 4) | param->linktype);
 224         cfpkt_addbdy(pkt, (param->priority << 3) | param->phyid);
 225         cfpkt_addbdy(pkt, param->endpoint & 0x03);
 226
 227         switch (param->linktype) {
 228         case CFCTRL_SRV_VEI:
 229                 break;
 230         case CFCTRL_SRV_VIDEO:
 231                 cfpkt_addbdy(pkt, (u8) param->u.video.connid);
 232                 break;
 233         case CFCTRL_SRV_DBG:
 234                 break;
 235         case CFCTRL_SRV_DATAGRAM:
 236                 tmp32 = cpu_to_le32(param->u.datagram.connid);
 237                 cfpkt_add_body(pkt, &tmp32, 4);
 238                 break;
 239         case CFCTRL_SRV_RFM:
 240                 /* Construct a frame, convert DatagramConnectionID to network
 241                  * format long and copy it out...
 242                  */
 243                 tmp32 = cpu_to_le32(param->u.rfm.connid);
 244                 cfpkt_add_body(pkt, &tmp32, 4);
 245                 /* Add volume name, including zero termination... */
 246                 cfpkt_add_body(pkt, param->u.rfm.volume,
 247                                strlen(param->u.rfm.volume) + 1);
 248                 break;
 249         case CFCTRL_SRV_UTIL:
 250                 tmp16 = cpu_to_le16(param->u.utility.fifosize_kb);
 251                 cfpkt_add_body(pkt, &tmp16, 2);
 252                 tmp16 = cpu_to_le16(param->u.utility.fifosize_bufs);
 253                 cfpkt_add_body(pkt, &tmp16, 2);
 254                 memset(utility_name, 0, sizeof(utility_name));
 255                 strncpy(utility_name, param->u.utility.name,
 256                         UTILITY_NAME_LENGTH - 1);
 257                 cfpkt_add_body(pkt, utility_name, UTILITY_NAME_LENGTH);
 258                 tmp8 = param->u.utility.paramlen;
 259                 cfpkt_add_body(pkt, &tmp8, 1);
 260                 cfpkt_add_body(pkt, param->u.utility.params,
 261                                param->u.utility.paramlen);
 262                 break;
 263         default:
 264                 pr_warn("Request setup of bad link type = %d\n",
 265                         param->linktype);
 266                 return -EINVAL;
 267         }
 268         req = kzalloc(sizeof(*req), GFP_KERNEL);
 269         if (!req) {
 270                 pr_warn("Out of memory\n");
 271                 return -ENOMEM;
 272         }
 273         req->client_layer = user_layer;
 274         req->cmd = CFCTRL_CMD_LINK_SETUP;
 275         req->param = *param;
 276         cfctrl_insert_req(cfctrl, req);
 277         init_info(cfpkt_info(pkt), cfctrl);
 278         /*
 279          * NOTE:Always send linkup and linkdown request on the same
 280          *      device as the payload. Otherwise old queued up payload
 281          *      might arrive with the newly allocated channel ID.
 282          */
 283         cfpkt_info(pkt)->dev_info->id = param->phyid;
 284         ret =
 285             cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
 286         if (ret < 0) {
 287                 int count;
 288
 289                 count = cfctrl_cancel_req(&cfctrl->serv.layer,
 290                                                 user_layer);
 291                 if (count != 1)
 292                         pr_err("Could not remove request (%d)", count);
 293                         return -ENODEV;
 294         }
 295         return 0;
 296 }
 297
 298 int cfctrl_linkdown_req(struct cflayer *layer, u8 channelid,
 299                                 struct cflayer *client)
 300 {
 301         int ret;
 302         struct cfctrl *cfctrl = container_obj(layer);
 303         struct cfpkt *pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
 304         if (!pkt) {
 305                 pr_warn("Out of memory\n");
 306                 return -ENOMEM;
 307         }
 308         cfpkt_addbdy(pkt, CFCTRL_CMD_LINK_DESTROY);
 309         cfpkt_addbdy(pkt, channelid);
 310         init_info(cfpkt_info(pkt), cfctrl);
 311         ret =
 312             cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
 313 #ifndef CAIF_NO_LOOP
 314         cfctrl->loop_linkused[channelid] = 0;
 315 #endif
 316         return ret;
 317 }
 318
 319 int cfctrl_cancel_req(struct cflayer *layr, struct cflayer *adap_layer)
 320 {
 321         struct cfctrl_request_info *p, *tmp;
 322         struct cfctrl *ctrl = container_obj(layr);
 323         int found = 0;
 324         spin_lock_bh(&ctrl->info_list_lock);
 325
 326         list_for_each_entry_safe(p, tmp, &ctrl->list, list) {
 327                 if (p->client_layer == adap_layer) {
 328                         list_del(&p->list);
 329                         kfree(p);
 330                         found++;
 331                 }
 332         }
 333
 334         spin_unlock_bh(&ctrl->info_list_lock);
 335         return found;
 336 }
 337
 338 static int cfctrl_recv(struct cflayer *layer, struct cfpkt *pkt)
 339 {
 340         u8 cmdrsp;
 341         u8 cmd;
 342         int ret = -1;
 343         u16 tmp16;
 344         u8 len;
 345         u8 param[255];
 346         u8 linkid;
 347         struct cfctrl *cfctrl = container_obj(layer);
 348         struct cfctrl_request_info rsp, *req;
 349
 350
 351         cfpkt_extr_head(pkt, &cmdrsp, 1);
 352         cmd = cmdrsp & CFCTRL_CMD_MASK;
 353         if (cmd != CFCTRL_CMD_LINK_ERR
 354             && CFCTRL_RSP_BIT != (CFCTRL_RSP_BIT & cmdrsp)) {
 355                 if (handle_loop(cfctrl, cmd, pkt) != 0)
 356                         cmdrsp |= CFCTRL_ERR_BIT;
 357         }
 358
 359         switch (cmd) {
 360         case CFCTRL_CMD_LINK_SETUP:
 361                 {
 362                         enum cfctrl_srv serv;
 363                         enum cfctrl_srv servtype;
 364                         u8 endpoint;
 365                         u8 physlinkid;
 366                         u8 prio;
 367                         u8 tmp;
 368                         u32 tmp32;
 369                         u8 *cp;
 370                         int i;
 371                         struct cfctrl_link_param linkparam;
 372                         memset(&linkparam, 0, sizeof(linkparam));
 373
 374                         cfpkt_extr_head(pkt, &tmp, 1);
 375
 376                         serv = tmp & CFCTRL_SRV_MASK;
 377                         linkparam.linktype = serv;
 378
 379                         servtype = tmp >> 4;
 380                         linkparam.chtype = servtype;
 381
 382                         cfpkt_extr_head(pkt, &tmp, 1);
 383                         physlinkid = tmp & 0x07;
 384                         prio = tmp >> 3;
 385
 386                         linkparam.priority = prio;
 387                         linkparam.phyid = physlinkid;
 388                         cfpkt_extr_head(pkt, &endpoint, 1);
 389                         linkparam.endpoint = endpoint & 0x03;
 390
 391                         switch (serv) {
 392                         case CFCTRL_SRV_VEI:
 393                         case CFCTRL_SRV_DBG:
 394                                 if (CFCTRL_ERR_BIT & cmdrsp)
 395                                         break;
 396                                 /* Link ID */
 397                                 cfpkt_extr_head(pkt, &linkid, 1);
 398                                 break;
 399                         case CFCTRL_SRV_VIDEO:
 400                                 cfpkt_extr_head(pkt, &tmp, 1);
 401                                 linkparam.u.video.connid = tmp;
 402                                 if (CFCTRL_ERR_BIT & cmdrsp)
 403                                         break;
 404                                 /* Link ID */
 405                                 cfpkt_extr_head(pkt, &linkid, 1);
 406                                 break;
 407
 408                         case CFCTRL_SRV_DATAGRAM:
 409                                 cfpkt_extr_head(pkt, &tmp32, 4);
 410                                 linkparam.u.datagram.connid =
 411                                     le32_to_cpu(tmp32);
 412                                 if (CFCTRL_ERR_BIT & cmdrsp)
 413                                         break;
 414                                 /* Link ID */
 415                                 cfpkt_extr_head(pkt, &linkid, 1);
 416                                 break;
 417                         case CFCTRL_SRV_RFM:
 418                                 /* Construct a frame, convert
 419                                  * DatagramConnectionID
 420                                  * to network format long and copy it out...
 421                                  */
 422                                 cfpkt_extr_head(pkt, &tmp32, 4);
 423                                 linkparam.u.rfm.connid =
 424                                   le32_to_cpu(tmp32);
 425                                 cp = (u8 *) linkparam.u.rfm.volume;
 426                                 for (cfpkt_extr_head(pkt, &tmp, 1);
 427                                      cfpkt_more(pkt) && tmp != '\0';
 428                                      cfpkt_extr_head(pkt, &tmp, 1))
 429                                         *cp++ = tmp;
 430                                 *cp = '\0';
 431
 432                                 if (CFCTRL_ERR_BIT & cmdrsp)
 433                                         break;
 434                                 /* Link ID */
 435                                 cfpkt_extr_head(pkt, &linkid, 1);
 436
 437                                 break;
 438                         case CFCTRL_SRV_UTIL:
 439                                 /* Construct a frame, convert
 440                                  * DatagramConnectionID
 441                                  * to network format long and copy it out...
 442                                  */
 443                                 /* Fifosize KB */
 444                                 cfpkt_extr_head(pkt, &tmp16, 2);
 445                                 linkparam.u.utility.fifosize_kb =
 446                                     le16_to_cpu(tmp16);
 447                                 /* Fifosize bufs */
 448                                 cfpkt_extr_head(pkt, &tmp16, 2);
 449                                 linkparam.u.utility.fifosize_bufs =
 450                                     le16_to_cpu(tmp16);
 451                                 /* name */
 452                                 cp = (u8 *) linkparam.u.utility.name;
 453                                 caif_assert(sizeof(linkparam.u.utility.name)
 454                                              >= UTILITY_NAME_LENGTH);
 455                                 for (i = 0;
 456                                      i < UTILITY_NAME_LENGTH
 457                                      && cfpkt_more(pkt); i++) {
 458                                         cfpkt_extr_head(pkt, &tmp, 1);
 459                                         *cp++ = tmp;
 460                                 }
 461                                 /* Length */
 462                                 cfpkt_extr_head(pkt, &len, 1);
 463                                 linkparam.u.utility.paramlen = len;
 464                                 /* Param Data */
 465                                 cp = linkparam.u.utility.params;
 466                                 while (cfpkt_more(pkt) && len--) {
 467                                         cfpkt_extr_head(pkt, &tmp, 1);
 468                                         *cp++ = tmp;
 469                                 }
 470                                 if (CFCTRL_ERR_BIT & cmdrsp)
 471                                         break;
 472                                 /* Link ID */
 473                                 cfpkt_extr_head(pkt, &linkid, 1);
 474                                 /* Length */
 475                                 cfpkt_extr_head(pkt, &len, 1);
 476                                 /* Param Data */
 477                                 cfpkt_extr_head(pkt, &param, len);
 478                                 break;
 479                         default:
 480                                 pr_warn("Request setup - invalid link type (%d)\n",
 481                                         serv);
 482                                 goto error;
 483                         }
 484
 485                         rsp.cmd = cmd;
 486                         rsp.param = linkparam;
 487                         spin_lock_bh(&cfctrl->info_list_lock);
 488                         req = cfctrl_remove_req(cfctrl, &rsp);
 489
 490                         if (CFCTRL_ERR_BIT == (CFCTRL_ERR_BIT & cmdrsp) ||
 491                                 cfpkt_erroneous(pkt)) {
 492                                 pr_err("Invalid O/E bit or parse error on CAIF control channel\n");
 493                                 cfctrl->res.reject_rsp(cfctrl->serv.layer.up,
 494                                                        0,
 495                                                        req ? req->client_layer
 496                                                        : NULL);
 497                         } else {
 498                                 cfctrl->res.linksetup_rsp(cfctrl->serv.
 499                                                           layer.up, linkid,
 500                                                           serv, physlinkid,
 501                                                           req ? req->
 502                                                           client_layer : NULL);
 503                         }
 504
 505                         if (req != NULL)
 506                                 kfree(req);
 507
 508                         spin_unlock_bh(&cfctrl->info_list_lock);
 509                 }
 510                 break;
 511         case CFCTRL_CMD_LINK_DESTROY:
 512                 cfpkt_extr_head(pkt, &linkid, 1);
 513                 cfctrl->res.linkdestroy_rsp(cfctrl->serv.layer.up, linkid);
 514                 break;
 515         case CFCTRL_CMD_LINK_ERR:
 516                 pr_err("Frame Error Indication received\n");
 517                 cfctrl->res.linkerror_ind();
 518                 break;
 519         case CFCTRL_CMD_ENUM:
 520                 cfctrl->res.enum_rsp();
 521                 break;
 522         case CFCTRL_CMD_SLEEP:
 523                 cfctrl->res.sleep_rsp();
 524                 break;
 525         case CFCTRL_CMD_WAKE:
 526                 cfctrl->res.wake_rsp();
 527                 break;
 528         case CFCTRL_CMD_LINK_RECONF:
 529                 cfctrl->res.restart_rsp();
 530                 break;
 531         case CFCTRL_CMD_RADIO_SET:
 532                 cfctrl->res.radioset_rsp();
 533                 break;
 534         default:
 535                 pr_err("Unrecognized Control Frame\n");
 536                 goto error;
 537                 break;
 538         }
 539         ret = 0;
 540 error:
 541         cfpkt_destroy(pkt);
 542         return ret;
 543 }
 544
 545 static void cfctrl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
 546                         int phyid)
 547 {
 548         struct cfctrl *this = container_obj(layr);
 549         switch (ctrl) {
 550         case _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND:
 551         case CAIF_CTRLCMD_FLOW_OFF_IND:
 552                 spin_lock_bh(&this->info_list_lock);
 553                 if (!list_empty(&this->list)) {
 554                         pr_debug("Received flow off in control layer\n");
 555                 }
 556                 spin_unlock_bh(&this->info_list_lock);
 557                 break;
 558         case _CAIF_CTRLCMD_PHYIF_DOWN_IND: {
 559                 struct cfctrl_request_info *p, *tmp;
 560
 561                 /* Find all connect request and report failure */
 562                 spin_lock_bh(&this->info_list_lock);
 563                 list_for_each_entry_safe(p, tmp, &this->list, list) {
 564                         if (p->param.phyid == phyid) {
 565                                 list_del(&p->list);
 566                                 p->client_layer->ctrlcmd(p->client_layer,
 567                                                 CAIF_CTRLCMD_INIT_FAIL_RSP,
 568                                                 phyid);
 569                                 kfree(p);
 570                         }
 571                 }
 572                 spin_unlock_bh(&this->info_list_lock);
 573                 break;
 574         }
 575         default:
 576                 break;
 577         }
 578 }
 579
 580 #ifndef CAIF_NO_LOOP
 581 static int handle_loop(struct cfctrl *ctrl, int cmd, struct cfpkt *pkt)
 582 {
 583         static int last_linkid;
 584         static int dec;
 585         u8 linkid, linktype, tmp;
 586         switch (cmd) {
 587         case CFCTRL_CMD_LINK_SETUP:
 588                 spin_lock_bh(&ctrl->loop_linkid_lock);
 589                 if (!dec) {
 590                         for (linkid = last_linkid + 1; linkid < 255; linkid++)
 591                                 if (!ctrl->loop_linkused[linkid])
 592                                         goto found;
 593                 }
 594                 dec = 1;
 595                 for (linkid = last_linkid - 1; linkid > 0; linkid--)
 596                         if (!ctrl->loop_linkused[linkid])
 597                                 goto found;
 598                 spin_unlock_bh(&ctrl->loop_linkid_lock);
 599
 600 found:
 601                 if (linkid < 10)
 602                         dec = 0;
 603
 604                 if (!ctrl->loop_linkused[linkid])
 605                         ctrl->loop_linkused[linkid] = 1;
 606
 607                 last_linkid = linkid;
 608
 609                 cfpkt_add_trail(pkt, &linkid, 1);
 610                 spin_unlock_bh(&ctrl->loop_linkid_lock);
 611                 cfpkt_peek_head(pkt, &linktype, 1);
 612                 if (linktype ==  CFCTRL_SRV_UTIL) {
 613                         tmp = 0x01;
 614                         cfpkt_add_trail(pkt, &tmp, 1);
 615                         cfpkt_add_trail(pkt, &tmp, 1);
 616                 }
 617                 break;
 618
 619         case CFCTRL_CMD_LINK_DESTROY:
 620                 spin_lock_bh(&ctrl->loop_linkid_lock);
 621                 cfpkt_peek_head(pkt, &linkid, 1);
 622                 ctrl->loop_linkused[linkid] = 0;
 623                 spin_unlock_bh(&ctrl->loop_linkid_lock);
 624                 break;
 625         default:
 626                 break;
 627         }
 628         return 0;
 629 }
 630 #endif