net/caif/cfctrl.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) ST-Ericsson AB 2010
   4  * Author:      Sjur Brendeland
   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 <linux/pkt_sched.h>
  13 #include <net/caif/caif_layer.h>
  14 #include <net/caif/cfpkt.h>
  15 #include <net/caif/cfctrl.h>
  16
  17 #define container_obj(layr) container_of(layr, struct cfctrl, serv.layer)
  18 #define UTILITY_NAME_LENGTH 16
  19 #define CFPKT_CTRL_PKT_LEN 20
  20
  21 #ifdef CAIF_NO_LOOP
  22 static int handle_loop(struct cfctrl *ctrl,
  23                        int cmd, struct cfpkt *pkt){
  24         return -1;
  25 }
  26 #else
  27 static int handle_loop(struct cfctrl *ctrl,
  28                        int cmd, struct cfpkt *pkt);
  29 #endif
  30 static int cfctrl_recv(struct cflayer *layr, struct cfpkt *pkt);
  31 static void cfctrl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
  32                            int phyid);
  33
  34
  35 struct cflayer *cfctrl_create(void)
  36 {
  37         struct dev_info dev_info;
  38         struct cfctrl *this =
  39                 kzalloc(sizeof(struct cfctrl), GFP_ATOMIC);
  40         if (!this)
  41                 return NULL;
  42         caif_assert(offsetof(struct cfctrl, serv.layer) == 0);
  43         memset(&dev_info, 0, sizeof(dev_info));
  44         dev_info.id = 0xff;
  45         cfsrvl_init(&this->serv, 0, &dev_info, false);
  46         atomic_set(&this->req_seq_no, 1);
  47         atomic_set(&this->rsp_seq_no, 1);
  48         this->serv.layer.receive = cfctrl_recv;
  49         sprintf(this->serv.layer.name, "ctrl");
  50         this->serv.layer.ctrlcmd = cfctrl_ctrlcmd;
  51 #ifndef CAIF_NO_LOOP
  52         spin_lock_init(&this->loop_linkid_lock);
  53         this->loop_linkid = 1;
  54 #endif
  55         spin_lock_init(&this->info_list_lock);
  56         INIT_LIST_HEAD(&this->list);
  57         return &this->serv.layer;
  58 }
  59
  60 void cfctrl_remove(struct cflayer *layer)
  61 {
  62         struct cfctrl_request_info *p, *tmp;
  63         struct cfctrl *ctrl = container_obj(layer);
  64
  65         spin_lock_bh(&ctrl->info_list_lock);
  66         list_for_each_entry_safe(p, tmp, &ctrl->list, list) {
  67                 list_del(&p->list);
  68                 kfree(p);
  69         }
  70         spin_unlock_bh(&ctrl->info_list_lock);
  71         kfree(layer);
  72 }
  73
  74 static bool param_eq(const struct cfctrl_link_param *p1,
  75                      const struct cfctrl_link_param *p2)
  76 {
  77         bool eq =
  78             p1->linktype == p2->linktype &&
  79             p1->priority == p2->priority &&
  80             p1->phyid == p2->phyid &&
  81             p1->endpoint == p2->endpoint && p1->chtype == p2->chtype;
  82
  83         if (!eq)
  84                 return false;
  85
  86         switch (p1->linktype) {
  87         case CFCTRL_SRV_VEI:
  88                 return true;
  89         case CFCTRL_SRV_DATAGRAM:
  90                 return p1->u.datagram.connid == p2->u.datagram.connid;
  91         case CFCTRL_SRV_RFM:
  92                 return
  93                     p1->u.rfm.connid == p2->u.rfm.connid &&
  94                     strcmp(p1->u.rfm.volume, p2->u.rfm.volume) == 0;
  95         case CFCTRL_SRV_UTIL:
  96                 return
  97                     p1->u.utility.fifosize_kb == p2->u.utility.fifosize_kb
  98                     && p1->u.utility.fifosize_bufs ==
  99                     p2->u.utility.fifosize_bufs
 100                     && strcmp(p1->u.utility.name, p2->u.utility.name) == 0
 101                     && p1->u.utility.paramlen == p2->u.utility.paramlen
 102                     && memcmp(p1->u.utility.params, p2->u.utility.params,
 103                               p1->u.utility.paramlen) == 0;
 104
 105         case CFCTRL_SRV_VIDEO:
 106                 return p1->u.video.connid == p2->u.video.connid;
 107         case CFCTRL_SRV_DBG:
 108                 return true;
 109         case CFCTRL_SRV_DECM:
 110                 return false;
 111         default:
 112                 return false;
 113         }
 114         return false;
 115 }
 116
 117 static bool cfctrl_req_eq(const struct cfctrl_request_info *r1,
 118                           const struct cfctrl_request_info *r2)
 119 {
 120         if (r1->cmd != r2->cmd)
 121                 return false;
 122         if (r1->cmd == CFCTRL_CMD_LINK_SETUP)
 123                 return param_eq(&r1->param, &r2->param);
 124         else
 125                 return r1->channel_id == r2->channel_id;
 126 }
 127
 128 /* Insert request at the end */
 129 static void cfctrl_insert_req(struct cfctrl *ctrl,
 130                               struct cfctrl_request_info *req)
 131 {
 132         spin_lock_bh(&ctrl->info_list_lock);
 133         atomic_inc(&ctrl->req_seq_no);
 134         req->sequence_no = atomic_read(&ctrl->req_seq_no);
 135         list_add_tail(&req->list, &ctrl->list);
 136         spin_unlock_bh(&ctrl->info_list_lock);
 137 }
 138
 139 /* Compare and remove request */
 140 static struct cfctrl_request_info *cfctrl_remove_req(struct cfctrl *ctrl,
 141                                                 struct cfctrl_request_info *req)
 142 {
 143         struct cfctrl_request_info *p, *tmp, *first;
 144
 145         first = list_first_entry(&ctrl->list, struct cfctrl_request_info, list);
 146
 147         list_for_each_entry_safe(p, tmp, &ctrl->list, list) {
 148                 if (cfctrl_req_eq(req, p)) {
 149                         if (p != first)
 150                                 pr_warn("Requests are not received in order\n");
 151
 152                         atomic_set(&ctrl->rsp_seq_no,
 153                                          p->sequence_no);
 154                         list_del(&p->list);
 155                         goto out;
 156                 }
 157         }
 158         p = NULL;
 159 out:
 160         return p;
 161 }
 162
 163 struct cfctrl_rsp *cfctrl_get_respfuncs(struct cflayer *layer)
 164 {
 165         struct cfctrl *this = container_obj(layer);
 166         return &this->res;
 167 }
 168
 169 static void init_info(struct caif_payload_info *info, struct cfctrl *cfctrl)
 170 {
 171         info->hdr_len = 0;
 172         info->channel_id = cfctrl->serv.layer.id;
 173         info->dev_info = &cfctrl->serv.dev_info;
 174 }
 175
 176 void cfctrl_enum_req(struct cflayer *layer, u8 physlinkid)
 177 {
 178         struct cfpkt *pkt;
 179         struct cfctrl *cfctrl = container_obj(layer);
 180         struct cflayer *dn = cfctrl->serv.layer.dn;
 181
 182         if (!dn) {
 183                 pr_debug("not able to send enum request\n");
 184                 return;
 185         }
 186         pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
 187         if (!pkt)
 188                 return;
 189         caif_assert(offsetof(struct cfctrl, serv.layer) == 0);
 190         init_info(cfpkt_info(pkt), cfctrl);
 191         cfpkt_info(pkt)->dev_info->id = physlinkid;
 192         cfctrl->serv.dev_info.id = physlinkid;
 193         cfpkt_addbdy(pkt, CFCTRL_CMD_ENUM);
 194         cfpkt_addbdy(pkt, physlinkid);
 195         cfpkt_set_prio(pkt, TC_PRIO_CONTROL);
 196         dn->transmit(dn, pkt);
 197 }
 198
 199 int cfctrl_linkup_request(struct cflayer *layer,
 200                           struct cfctrl_link_param *param,
 201                           struct cflayer *user_layer)
 202 {
 203         struct cfctrl *cfctrl = container_obj(layer);
 204         u32 tmp32;
 205         u16 tmp16;
 206         u8 tmp8;
 207         struct cfctrl_request_info *req;
 208         int ret;
 209         char utility_name[16];
 210         struct cfpkt *pkt;
 211         struct cflayer *dn = cfctrl->serv.layer.dn;
 212
 213         if (!dn) {
 214                 pr_debug("not able to send linkup request\n");
 215                 return -ENODEV;
 216         }
 217
 218         if (cfctrl_cancel_req(layer, user_layer) > 0) {
 219                 /* Slight Paranoia, check if already connecting */
 220                 pr_err("Duplicate connect request for same client\n");
 221                 WARN_ON(1);
 222                 return -EALREADY;
 223         }
 224
 225         pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
 226         if (!pkt)
 227                 return -ENOMEM;
 228         cfpkt_addbdy(pkt, CFCTRL_CMD_LINK_SETUP);
 229         cfpkt_addbdy(pkt, (param->chtype << 4) | param->linktype);
 230         cfpkt_addbdy(pkt, (param->priority << 3) | param->phyid);
 231         cfpkt_addbdy(pkt, param->endpoint & 0x03);
 232
 233         switch (param->linktype) {
 234         case CFCTRL_SRV_VEI:
 235                 break;
 236         case CFCTRL_SRV_VIDEO:
 237                 cfpkt_addbdy(pkt, (u8) param->u.video.connid);
 238                 break;
 239         case CFCTRL_SRV_DBG:
 240                 break;
 241         case CFCTRL_SRV_DATAGRAM:
 242                 tmp32 = cpu_to_le32(param->u.datagram.connid);
 243                 cfpkt_add_body(pkt, &tmp32, 4);
 244                 break;
 245         case CFCTRL_SRV_RFM:
 246                 /* Construct a frame, convert DatagramConnectionID to network
 247                  * format long and copy it out...
 248                  */
 249                 tmp32 = cpu_to_le32(param->u.rfm.connid);
 250                 cfpkt_add_body(pkt, &tmp32, 4);
 251                 /* Add volume name, including zero termination... */
 252                 cfpkt_add_body(pkt, param->u.rfm.volume,
 253                                strlen(param->u.rfm.volume) + 1);
 254                 break;
 255         case CFCTRL_SRV_UTIL:
 256                 tmp16 = cpu_to_le16(param->u.utility.fifosize_kb);
 257                 cfpkt_add_body(pkt, &tmp16, 2);
 258                 tmp16 = cpu_to_le16(param->u.utility.fifosize_bufs);
 259                 cfpkt_add_body(pkt, &tmp16, 2);
 260                 memset(utility_name, 0, sizeof(utility_name));
 261                 strlcpy(utility_name, param->u.utility.name,
 262                         UTILITY_NAME_LENGTH);
 263                 cfpkt_add_body(pkt, utility_name, UTILITY_NAME_LENGTH);
 264                 tmp8 = param->u.utility.paramlen;
 265                 cfpkt_add_body(pkt, &tmp8, 1);
 266                 cfpkt_add_body(pkt, param->u.utility.params,
 267                                param->u.utility.paramlen);
 268                 break;
 269         default:
 270                 pr_warn("Request setup of bad link type = %d\n",
 271                         param->linktype);
 272                 return -EINVAL;
 273         }
 274         req = kzalloc(sizeof(*req), GFP_KERNEL);
 275         if (!req)
 276                 return -ENOMEM;
 277         req->client_layer = user_layer;
 278         req->cmd = CFCTRL_CMD_LINK_SETUP;
 279         req->param = *param;
 280         cfctrl_insert_req(cfctrl, req);
 281         init_info(cfpkt_info(pkt), cfctrl);
 282         /*
 283          * NOTE:Always send linkup and linkdown request on the same
 284          *      device as the payload. Otherwise old queued up payload
 285          *      might arrive with the newly allocated channel ID.
 286          */
 287         cfpkt_info(pkt)->dev_info->id = param->phyid;
 288         cfpkt_set_prio(pkt, TC_PRIO_CONTROL);
 289         ret =
 290             dn->transmit(dn, pkt);
 291         if (ret < 0) {
 292                 int count;
 293
 294                 count = cfctrl_cancel_req(&cfctrl->serv.layer,
 295                                                 user_layer);
 296                 if (count != 1) {
 297                         pr_err("Could not remove request (%d)", count);
 298                         return -ENODEV;
 299                 }
 300         }
 301         return 0;
 302 }
 303
 304 int cfctrl_linkdown_req(struct cflayer *layer, u8 channelid,
 305                         struct cflayer *client)
 306 {
 307         int ret;
 308         struct cfpkt *pkt;
 309         struct cfctrl *cfctrl = container_obj(layer);
 310         struct cflayer *dn = cfctrl->serv.layer.dn;
 311
 312         if (!dn) {
 313                 pr_debug("not able to send link-down request\n");
 314                 return -ENODEV;
 315         }
 316         pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
 317         if (!pkt)
 318                 return -ENOMEM;
 319         cfpkt_addbdy(pkt, CFCTRL_CMD_LINK_DESTROY);
 320         cfpkt_addbdy(pkt, channelid);
 321         init_info(cfpkt_info(pkt), cfctrl);
 322         cfpkt_set_prio(pkt, TC_PRIO_CONTROL);
 323         ret =
 324             dn->transmit(dn, pkt);
 325 #ifndef CAIF_NO_LOOP
 326         cfctrl->loop_linkused[channelid] = 0;
 327 #endif
 328         return ret;
 329 }
 330
 331 int cfctrl_cancel_req(struct cflayer *layr, struct cflayer *adap_layer)
 332 {
 333         struct cfctrl_request_info *p, *tmp;
 334         struct cfctrl *ctrl = container_obj(layr);
 335         int found = 0;
 336         spin_lock_bh(&ctrl->info_list_lock);
 337
 338         list_for_each_entry_safe(p, tmp, &ctrl->list, list) {
 339                 if (p->client_layer == adap_layer) {
 340                         list_del(&p->list);
 341                         kfree(p);
 342                         found++;
 343                 }
 344         }
 345
 346         spin_unlock_bh(&ctrl->info_list_lock);
 347         return found;
 348 }
 349
 350 static int cfctrl_recv(struct cflayer *layer, struct cfpkt *pkt)
 351 {
 352         u8 cmdrsp;
 353         u8 cmd;
 354         int ret = -1;
 355         u8 len;
 356         u8 param[255];
 357         u8 linkid = 0;
 358         struct cfctrl *cfctrl = container_obj(layer);
 359         struct cfctrl_request_info rsp, *req;
 360
 361
 362         cmdrsp = cfpkt_extr_head_u8(pkt);
 363         cmd = cmdrsp & CFCTRL_CMD_MASK;
 364         if (cmd != CFCTRL_CMD_LINK_ERR
 365             && CFCTRL_RSP_BIT != (CFCTRL_RSP_BIT & cmdrsp)
 366                 && CFCTRL_ERR_BIT != (CFCTRL_ERR_BIT & cmdrsp)) {
 367                 if (handle_loop(cfctrl, cmd, pkt) != 0)
 368                         cmdrsp |= CFCTRL_ERR_BIT;
 369         }
 370
 371         switch (cmd) {
 372         case CFCTRL_CMD_LINK_SETUP:
 373                 {
 374                         enum cfctrl_srv serv;
 375                         enum cfctrl_srv servtype;
 376                         u8 endpoint;
 377                         u8 physlinkid;
 378                         u8 prio;
 379                         u8 tmp;
 380                         u8 *cp;
 381                         int i;
 382                         struct cfctrl_link_param linkparam;
 383                         memset(&linkparam, 0, sizeof(linkparam));
 384
 385                         tmp = cfpkt_extr_head_u8(pkt);
 386
 387                         serv = tmp & CFCTRL_SRV_MASK;
 388                         linkparam.linktype = serv;
 389
 390                         servtype = tmp >> 4;
 391                         linkparam.chtype = servtype;
 392
 393                         tmp = cfpkt_extr_head_u8(pkt);
 394                         physlinkid = tmp & 0x07;
 395                         prio = tmp >> 3;
 396
 397                         linkparam.priority = prio;
 398                         linkparam.phyid = physlinkid;
 399                         endpoint = cfpkt_extr_head_u8(pkt);
 400                         linkparam.endpoint = endpoint & 0x03;
 401
 402                         switch (serv) {
 403                         case CFCTRL_SRV_VEI:
 404                         case CFCTRL_SRV_DBG:
 405                                 if (CFCTRL_ERR_BIT & cmdrsp)
 406                                         break;
 407                                 /* Link ID */
 408                                 linkid = cfpkt_extr_head_u8(pkt);
 409                                 break;
 410                         case CFCTRL_SRV_VIDEO:
 411                                 tmp = cfpkt_extr_head_u8(pkt);
 412                                 linkparam.u.video.connid = tmp;
 413                                 if (CFCTRL_ERR_BIT & cmdrsp)
 414                                         break;
 415                                 /* Link ID */
 416                                 linkid = cfpkt_extr_head_u8(pkt);
 417                                 break;
 418
 419                         case CFCTRL_SRV_DATAGRAM:
 420                                 linkparam.u.datagram.connid =
 421                                     cfpkt_extr_head_u32(pkt);
 422                                 if (CFCTRL_ERR_BIT & cmdrsp)
 423                                         break;
 424                                 /* Link ID */
 425                                 linkid = cfpkt_extr_head_u8(pkt);
 426                                 break;
 427                         case CFCTRL_SRV_RFM:
 428                                 /* Construct a frame, convert
 429                                  * DatagramConnectionID
 430                                  * to network format long and copy it out...
 431                                  */
 432                                 linkparam.u.rfm.connid =
 433                                     cfpkt_extr_head_u32(pkt);
 434                                 cp = (u8 *) linkparam.u.rfm.volume;
 435                                 for (tmp = cfpkt_extr_head_u8(pkt);
 436                                      cfpkt_more(pkt) && tmp != '\0';
 437                                      tmp = cfpkt_extr_head_u8(pkt))
 438                                         *cp++ = tmp;
 439                                 *cp = '\0';
 440
 441                                 if (CFCTRL_ERR_BIT & cmdrsp)
 442                                         break;
 443                                 /* Link ID */
 444                                 linkid = cfpkt_extr_head_u8(pkt);
 445
 446                                 break;
 447                         case CFCTRL_SRV_UTIL:
 448                                 /* Construct a frame, convert
 449                                  * DatagramConnectionID
 450                                  * to network format long and copy it out...
 451                                  */
 452                                 /* Fifosize KB */
 453                                 linkparam.u.utility.fifosize_kb =
 454                                     cfpkt_extr_head_u16(pkt);
 455                                 /* Fifosize bufs */
 456                                 linkparam.u.utility.fifosize_bufs =
 457                                     cfpkt_extr_head_u16(pkt);
 458                                 /* name */
 459                                 cp = (u8 *) linkparam.u.utility.name;
 460                                 caif_assert(sizeof(linkparam.u.utility.name)
 461                                              >= UTILITY_NAME_LENGTH);
 462                                 for (i = 0;
 463                                      i < UTILITY_NAME_LENGTH
 464                                      && cfpkt_more(pkt); i++) {
 465                                         tmp = cfpkt_extr_head_u8(pkt);
 466                                         *cp++ = tmp;
 467                                 }
 468                                 /* Length */
 469                                 len = cfpkt_extr_head_u8(pkt);
 470                                 linkparam.u.utility.paramlen = len;
 471                                 /* Param Data */
 472                                 cp = linkparam.u.utility.params;
 473                                 while (cfpkt_more(pkt) && len--) {
 474                                         tmp = cfpkt_extr_head_u8(pkt);
 475                                         *cp++ = tmp;
 476                                 }
 477                                 if (CFCTRL_ERR_BIT & cmdrsp)
 478                                         break;
 479                                 /* Link ID */
 480                                 linkid = cfpkt_extr_head_u8(pkt);
 481                                 /* Length */
 482                                 len = cfpkt_extr_head_u8(pkt);
 483                                 /* Param Data */
 484                                 cfpkt_extr_head(pkt, &param, len);
 485                                 break;
 486                         default:
 487                                 pr_warn("Request setup, invalid type (%d)\n",
 488                                         serv);
 489                                 goto error;
 490                         }
 491
 492                         rsp.cmd = cmd;
 493                         rsp.param = linkparam;
 494                         spin_lock_bh(&cfctrl->info_list_lock);
 495                         req = cfctrl_remove_req(cfctrl, &rsp);
 496
 497                         if (CFCTRL_ERR_BIT == (CFCTRL_ERR_BIT & cmdrsp) ||
 498                                 cfpkt_erroneous(pkt)) {
 499                                 pr_err("Invalid O/E bit or parse error "
 500                                                 "on CAIF control channel\n");
 501                                 cfctrl->res.reject_rsp(cfctrl->serv.layer.up,
 502                                                        0,
 503                                                        req ? req->client_layer
 504                                                        : NULL);
 505                         } else {
 506                                 cfctrl->res.linksetup_rsp(cfctrl->serv.
 507                                                           layer.up, linkid,
 508                                                           serv, physlinkid,
 509                                                           req ? req->
 510                                                           client_layer : NULL);
 511                         }
 512
 513                         kfree(req);
 514
 515                         spin_unlock_bh(&cfctrl->info_list_lock);
 516                 }
 517                 break;
 518         case CFCTRL_CMD_LINK_DESTROY:
 519                 linkid = cfpkt_extr_head_u8(pkt);
 520                 cfctrl->res.linkdestroy_rsp(cfctrl->serv.layer.up, linkid);
 521                 break;
 522         case CFCTRL_CMD_LINK_ERR:
 523                 pr_err("Frame Error Indication received\n");
 524                 cfctrl->res.linkerror_ind();
 525                 break;
 526         case CFCTRL_CMD_ENUM:
 527                 cfctrl->res.enum_rsp();
 528                 break;
 529         case CFCTRL_CMD_SLEEP:
 530                 cfctrl->res.sleep_rsp();
 531                 break;
 532         case CFCTRL_CMD_WAKE:
 533                 cfctrl->res.wake_rsp();
 534                 break;
 535         case CFCTRL_CMD_LINK_RECONF:
 536                 cfctrl->res.restart_rsp();
 537                 break;
 538         case CFCTRL_CMD_RADIO_SET:
 539                 cfctrl->res.radioset_rsp();
 540                 break;
 541         default:
 542                 pr_err("Unrecognized Control Frame\n");
 543                 goto error;
 544         }
 545         ret = 0;
 546 error:
 547         cfpkt_destroy(pkt);
 548         return ret;
 549 }
 550
 551 static void cfctrl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
 552                            int phyid)
 553 {
 554         struct cfctrl *this = container_obj(layr);
 555         switch (ctrl) {
 556         case _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND:
 557         case CAIF_CTRLCMD_FLOW_OFF_IND:
 558                 spin_lock_bh(&this->info_list_lock);
 559                 if (!list_empty(&this->list))
 560                         pr_debug("Received flow off in control layer\n");
 561                 spin_unlock_bh(&this->info_list_lock);
 562                 break;
 563         case _CAIF_CTRLCMD_PHYIF_DOWN_IND: {
 564                 struct cfctrl_request_info *p, *tmp;
 565
 566                 /* Find all connect request and report failure */
 567                 spin_lock_bh(&this->info_list_lock);
 568                 list_for_each_entry_safe(p, tmp, &this->list, list) {
 569                         if (p->param.phyid == phyid) {
 570                                 list_del(&p->list);
 571                                 p->client_layer->ctrlcmd(p->client_layer,
 572                                                 CAIF_CTRLCMD_INIT_FAIL_RSP,
 573                                                 phyid);
 574                                 kfree(p);
 575                         }
 576                 }
 577                 spin_unlock_bh(&this->info_list_lock);
 578                 break;
 579         }
 580         default:
 581                 break;
 582         }
 583 }
 584
 585 #ifndef CAIF_NO_LOOP
 586 static int handle_loop(struct cfctrl *ctrl, int cmd, struct cfpkt *pkt)
 587 {
 588         static int last_linkid;
 589         static int dec;
 590         u8 linkid, linktype, tmp;
 591         switch (cmd) {
 592         case CFCTRL_CMD_LINK_SETUP:
 593                 spin_lock_bh(&ctrl->loop_linkid_lock);
 594                 if (!dec) {
 595                         for (linkid = last_linkid + 1; linkid < 254; linkid++)
 596                                 if (!ctrl->loop_linkused[linkid])
 597                                         goto found;
 598                 }
 599                 dec = 1;
 600                 for (linkid = last_linkid - 1; linkid > 1; linkid--)
 601                         if (!ctrl->loop_linkused[linkid])
 602                                 goto found;
 603                 spin_unlock_bh(&ctrl->loop_linkid_lock);
 604                 return -1;
 605 found:
 606                 if (linkid < 10)
 607                         dec = 0;
 608
 609                 if (!ctrl->loop_linkused[linkid])
 610                         ctrl->loop_linkused[linkid] = 1;
 611
 612                 last_linkid = linkid;
 613
 614                 cfpkt_add_trail(pkt, &linkid, 1);
 615                 spin_unlock_bh(&ctrl->loop_linkid_lock);
 616                 cfpkt_peek_head(pkt, &linktype, 1);
 617                 if (linktype ==  CFCTRL_SRV_UTIL) {
 618                         tmp = 0x01;
 619                         cfpkt_add_trail(pkt, &tmp, 1);
 620                         cfpkt_add_trail(pkt, &tmp, 1);
 621                 }
 622                 break;
 623
 624         case CFCTRL_CMD_LINK_DESTROY:
 625                 spin_lock_bh(&ctrl->loop_linkid_lock);
 626                 cfpkt_peek_head(pkt, &linkid, 1);
 627                 ctrl->loop_linkused[linkid] = 0;
 628                 spin_unlock_bh(&ctrl->loop_linkid_lock);
 629                 break;
 630         default:
 631                 break;
 632         }
 633         return 0;
 634 }
 635 #endif