caif: Bugfix - use standard Linux lists
[linux-2.6.git] / 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 #include <linux/stddef.h>
8 #include <linux/spinlock.h>
9 #include <linux/slab.h>
10 #include <net/caif/caif_layer.h>
11 #include <net/caif/cfpkt.h>
12 #include <net/caif/cfctrl.h>
13
14 #define container_obj(layr) container_of(layr, struct cfctrl, serv.layer)
15 #define UTILITY_NAME_LENGTH 16
16 #define CFPKT_CTRL_PKT_LEN 20
17
18
19 #ifdef CAIF_NO_LOOP
20 static int handle_loop(struct cfctrl *ctrl,
21                               int cmd, struct cfpkt *pkt){
22         return CAIF_FAILURE;
23 }
24 #else
25 static int handle_loop(struct cfctrl *ctrl,
26                 int cmd, struct cfpkt *pkt);
27 #endif
28 static int cfctrl_recv(struct cflayer *layr, struct cfpkt *pkt);
29 static void cfctrl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
30                            int phyid);
31
32
33 struct cflayer *cfctrl_create(void)
34 {
35         struct dev_info dev_info;
36         struct cfctrl *this =
37                 kmalloc(sizeof(struct cfctrl), GFP_ATOMIC);
38         if (!this) {
39                 pr_warning("CAIF: %s(): Out of memory\n", __func__);
40                 return NULL;
41         }
42         caif_assert(offsetof(struct cfctrl, serv.layer) == 0);
43         memset(&dev_info, 0, sizeof(dev_info));
44         dev_info.id = 0xff;
45         memset(this, 0, sizeof(*this));
46         cfsrvl_init(&this->serv, 0, &dev_info);
47         atomic_set(&this->req_seq_no, 1);
48         atomic_set(&this->rsp_seq_no, 1);
49         this->serv.layer.receive = cfctrl_recv;
50         sprintf(this->serv.layer.name, "ctrl");
51         this->serv.layer.ctrlcmd = cfctrl_ctrlcmd;
52         spin_lock_init(&this->loop_linkid_lock);
53         spin_lock_init(&this->info_list_lock);
54         INIT_LIST_HEAD(&this->list);
55         this->loop_linkid = 1;
56         return &this->serv.layer;
57 }
58
59 static bool param_eq(struct cfctrl_link_param *p1, struct cfctrl_link_param *p2)
60 {
61         bool eq =
62             p1->linktype == p2->linktype &&
63             p1->priority == p2->priority &&
64             p1->phyid == p2->phyid &&
65             p1->endpoint == p2->endpoint && p1->chtype == p2->chtype;
66
67         if (!eq)
68                 return false;
69
70         switch (p1->linktype) {
71         case CFCTRL_SRV_VEI:
72                 return true;
73         case CFCTRL_SRV_DATAGRAM:
74                 return p1->u.datagram.connid == p2->u.datagram.connid;
75         case CFCTRL_SRV_RFM:
76                 return
77                     p1->u.rfm.connid == p2->u.rfm.connid &&
78                     strcmp(p1->u.rfm.volume, p2->u.rfm.volume) == 0;
79         case CFCTRL_SRV_UTIL:
80                 return
81                     p1->u.utility.fifosize_kb == p2->u.utility.fifosize_kb
82                     && p1->u.utility.fifosize_bufs ==
83                     p2->u.utility.fifosize_bufs
84                     && strcmp(p1->u.utility.name, p2->u.utility.name) == 0
85                     && p1->u.utility.paramlen == p2->u.utility.paramlen
86                     && memcmp(p1->u.utility.params, p2->u.utility.params,
87                               p1->u.utility.paramlen) == 0;
88
89         case CFCTRL_SRV_VIDEO:
90                 return p1->u.video.connid == p2->u.video.connid;
91         case CFCTRL_SRV_DBG:
92                 return true;
93         case CFCTRL_SRV_DECM:
94                 return false;
95         default:
96                 return false;
97         }
98         return false;
99 }
100
101 bool cfctrl_req_eq(struct cfctrl_request_info *r1,
102                    struct cfctrl_request_info *r2)
103 {
104         if (r1->cmd != r2->cmd)
105                 return false;
106         if (r1->cmd == CFCTRL_CMD_LINK_SETUP)
107                 return param_eq(&r1->param, &r2->param);
108         else
109                 return r1->channel_id == r2->channel_id;
110 }
111
112 /* Insert request at the end */
113 void cfctrl_insert_req(struct cfctrl *ctrl,
114                               struct cfctrl_request_info *req)
115 {
116         spin_lock(&ctrl->info_list_lock);
117         atomic_inc(&ctrl->req_seq_no);
118         req->sequence_no = atomic_read(&ctrl->req_seq_no);
119         list_add_tail(&req->list, &ctrl->list);
120         spin_unlock(&ctrl->info_list_lock);
121 }
122
123 /* Compare and remove request */
124 struct cfctrl_request_info *cfctrl_remove_req(struct cfctrl *ctrl,
125                                               struct cfctrl_request_info *req)
126 {
127         struct cfctrl_request_info *p, *tmp, *first;
128
129         spin_lock(&ctrl->info_list_lock);
130         first = list_first_entry(&ctrl->list, struct cfctrl_request_info, list);
131
132         list_for_each_entry_safe(p, tmp, &ctrl->list, list) {
133                 if (cfctrl_req_eq(req, p)) {
134                         if (p != first)
135                                 pr_warning("CAIF: %s(): Requests are not "
136                                         "received in order\n",
137                                         __func__);
138
139                         atomic_set(&ctrl->rsp_seq_no,
140                                          p->sequence_no);
141                         list_del(&p->list);
142                         goto out;
143                 }
144         }
145         p = NULL;
146 out:
147         spin_unlock(&ctrl->info_list_lock);
148         return p;
149 }
150
151 struct cfctrl_rsp *cfctrl_get_respfuncs(struct cflayer *layer)
152 {
153         struct cfctrl *this = container_obj(layer);
154         return &this->res;
155 }
156
157 void cfctrl_set_dnlayer(struct cflayer *this, struct cflayer *dn)
158 {
159         this->dn = dn;
160 }
161
162 void cfctrl_set_uplayer(struct cflayer *this, struct cflayer *up)
163 {
164         this->up = up;
165 }
166
167 static void init_info(struct caif_payload_info *info, struct cfctrl *cfctrl)
168 {
169         info->hdr_len = 0;
170         info->channel_id = cfctrl->serv.layer.id;
171         info->dev_info = &cfctrl->serv.dev_info;
172 }
173
174 void cfctrl_enum_req(struct cflayer *layer, u8 physlinkid)
175 {
176         struct cfctrl *cfctrl = container_obj(layer);
177         int ret;
178         struct cfpkt *pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
179         if (!pkt) {
180                 pr_warning("CAIF: %s(): Out of memory\n", __func__);
181                 return;
182         }
183         caif_assert(offsetof(struct cfctrl, serv.layer) == 0);
184         init_info(cfpkt_info(pkt), cfctrl);
185         cfpkt_info(pkt)->dev_info->id = physlinkid;
186         cfctrl->serv.dev_info.id = physlinkid;
187         cfpkt_addbdy(pkt, CFCTRL_CMD_ENUM);
188         cfpkt_addbdy(pkt, physlinkid);
189         ret =
190             cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
191         if (ret < 0) {
192                 pr_err("CAIF: %s(): Could not transmit enum message\n",
193                         __func__);
194                 cfpkt_destroy(pkt);
195         }
196 }
197
198 int cfctrl_linkup_request(struct cflayer *layer,
199                            struct cfctrl_link_param *param,
200                            struct cflayer *user_layer)
201 {
202         struct cfctrl *cfctrl = container_obj(layer);
203         u32 tmp32;
204         u16 tmp16;
205         u8 tmp8;
206         struct cfctrl_request_info *req;
207         int ret;
208         char utility_name[16];
209         struct cfpkt *pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
210         if (!pkt) {
211                 pr_warning("CAIF: %s(): Out of memory\n", __func__);
212                 return -ENOMEM;
213         }
214         cfpkt_addbdy(pkt, CFCTRL_CMD_LINK_SETUP);
215         cfpkt_addbdy(pkt, (param->chtype << 4) + param->linktype);
216         cfpkt_addbdy(pkt, (param->priority << 3) + param->phyid);
217         cfpkt_addbdy(pkt, param->endpoint & 0x03);
218
219         switch (param->linktype) {
220         case CFCTRL_SRV_VEI:
221                 break;
222         case CFCTRL_SRV_VIDEO:
223                 cfpkt_addbdy(pkt, (u8) param->u.video.connid);
224                 break;
225         case CFCTRL_SRV_DBG:
226                 break;
227         case CFCTRL_SRV_DATAGRAM:
228                 tmp32 = cpu_to_le32(param->u.datagram.connid);
229                 cfpkt_add_body(pkt, &tmp32, 4);
230                 break;
231         case CFCTRL_SRV_RFM:
232                 /* Construct a frame, convert DatagramConnectionID to network
233                  * format long and copy it out...
234                  */
235                 tmp32 = cpu_to_le32(param->u.rfm.connid);
236                 cfpkt_add_body(pkt, &tmp32, 4);
237                 /* Add volume name, including zero termination... */
238                 cfpkt_add_body(pkt, param->u.rfm.volume,
239                                strlen(param->u.rfm.volume) + 1);
240                 break;
241         case CFCTRL_SRV_UTIL:
242                 tmp16 = cpu_to_le16(param->u.utility.fifosize_kb);
243                 cfpkt_add_body(pkt, &tmp16, 2);
244                 tmp16 = cpu_to_le16(param->u.utility.fifosize_bufs);
245                 cfpkt_add_body(pkt, &tmp16, 2);
246                 memset(utility_name, 0, sizeof(utility_name));
247                 strncpy(utility_name, param->u.utility.name,
248                         UTILITY_NAME_LENGTH - 1);
249                 cfpkt_add_body(pkt, utility_name, UTILITY_NAME_LENGTH);
250                 tmp8 = param->u.utility.paramlen;
251                 cfpkt_add_body(pkt, &tmp8, 1);
252                 cfpkt_add_body(pkt, param->u.utility.params,
253                                param->u.utility.paramlen);
254                 break;
255         default:
256                 pr_warning("CAIF: %s():Request setup of bad link type = %d\n",
257                            __func__, param->linktype);
258                 return -EINVAL;
259         }
260         req = kzalloc(sizeof(*req), GFP_KERNEL);
261         if (!req) {
262                 pr_warning("CAIF: %s(): Out of memory\n", __func__);
263                 return -ENOMEM;
264         }
265         req->client_layer = user_layer;
266         req->cmd = CFCTRL_CMD_LINK_SETUP;
267         req->param = *param;
268         cfctrl_insert_req(cfctrl, req);
269         init_info(cfpkt_info(pkt), cfctrl);
270         /*
271          * NOTE:Always send linkup and linkdown request on the same
272          *      device as the payload. Otherwise old queued up payload
273          *      might arrive with the newly allocated channel ID.
274          */
275         cfpkt_info(pkt)->dev_info->id = param->phyid;
276         ret =
277             cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
278         if (ret < 0) {
279                 pr_err("CAIF: %s(): Could not transmit linksetup request\n",
280                         __func__);
281                 cfpkt_destroy(pkt);
282                 return -ENODEV;
283         }
284         return 0;
285 }
286
287 int cfctrl_linkdown_req(struct cflayer *layer, u8 channelid,
288                                 struct cflayer *client)
289 {
290         int ret;
291         struct cfctrl *cfctrl = container_obj(layer);
292         struct cfpkt *pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
293         if (!pkt) {
294                 pr_warning("CAIF: %s(): Out of memory\n", __func__);
295                 return -ENOMEM;
296         }
297         cfpkt_addbdy(pkt, CFCTRL_CMD_LINK_DESTROY);
298         cfpkt_addbdy(pkt, channelid);
299         init_info(cfpkt_info(pkt), cfctrl);
300         ret =
301             cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
302         if (ret < 0) {
303                 pr_err("CAIF: %s(): Could not transmit link-down request\n",
304                         __func__);
305                 cfpkt_destroy(pkt);
306         }
307         return ret;
308 }
309
310 void cfctrl_sleep_req(struct cflayer *layer)
311 {
312         int ret;
313         struct cfctrl *cfctrl = container_obj(layer);
314         struct cfpkt *pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
315         if (!pkt) {
316                 pr_warning("CAIF: %s(): Out of memory\n", __func__);
317                 return;
318         }
319         cfpkt_addbdy(pkt, CFCTRL_CMD_SLEEP);
320         init_info(cfpkt_info(pkt), cfctrl);
321         ret =
322             cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
323         if (ret < 0)
324                 cfpkt_destroy(pkt);
325 }
326
327 void cfctrl_wake_req(struct cflayer *layer)
328 {
329         int ret;
330         struct cfctrl *cfctrl = container_obj(layer);
331         struct cfpkt *pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
332         if (!pkt) {
333                 pr_warning("CAIF: %s(): Out of memory\n", __func__);
334                 return;
335         }
336         cfpkt_addbdy(pkt, CFCTRL_CMD_WAKE);
337         init_info(cfpkt_info(pkt), cfctrl);
338         ret =
339             cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
340         if (ret < 0)
341                 cfpkt_destroy(pkt);
342 }
343
344 void cfctrl_getstartreason_req(struct cflayer *layer)
345 {
346         int ret;
347         struct cfctrl *cfctrl = container_obj(layer);
348         struct cfpkt *pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
349         if (!pkt) {
350                 pr_warning("CAIF: %s(): Out of memory\n", __func__);
351                 return;
352         }
353         cfpkt_addbdy(pkt, CFCTRL_CMD_START_REASON);
354         init_info(cfpkt_info(pkt), cfctrl);
355         ret =
356             cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
357         if (ret < 0)
358                 cfpkt_destroy(pkt);
359 }
360
361
362 void cfctrl_cancel_req(struct cflayer *layr, struct cflayer *adap_layer)
363 {
364         struct cfctrl_request_info *p, *tmp;
365         struct cfctrl *ctrl = container_obj(layr);
366         spin_lock(&ctrl->info_list_lock);
367         pr_warning("CAIF: %s(): enter\n", __func__);
368
369         list_for_each_entry_safe(p, tmp, &ctrl->list, list) {
370                 if (p->client_layer == adap_layer) {
371                         pr_warning("CAIF: %s(): cancel req :%d\n", __func__,
372                                         p->sequence_no);
373                         list_del(&p->list);
374                         kfree(p);
375                 }
376         }
377
378         spin_unlock(&ctrl->info_list_lock);
379 }
380
381 static int cfctrl_recv(struct cflayer *layer, struct cfpkt *pkt)
382 {
383         u8 cmdrsp;
384         u8 cmd;
385         int ret = -1;
386         u16 tmp16;
387         u8 len;
388         u8 param[255];
389         u8 linkid;
390         struct cfctrl *cfctrl = container_obj(layer);
391         struct cfctrl_request_info rsp, *req;
392
393
394         cfpkt_extr_head(pkt, &cmdrsp, 1);
395         cmd = cmdrsp & CFCTRL_CMD_MASK;
396         if (cmd != CFCTRL_CMD_LINK_ERR
397             && CFCTRL_RSP_BIT != (CFCTRL_RSP_BIT & cmdrsp)) {
398                 if (handle_loop(cfctrl, cmd, pkt) == CAIF_FAILURE)
399                         cmdrsp |= CFCTRL_ERR_BIT;
400         }
401
402         switch (cmd) {
403         case CFCTRL_CMD_LINK_SETUP:
404                 {
405                         enum cfctrl_srv serv;
406                         enum cfctrl_srv servtype;
407                         u8 endpoint;
408                         u8 physlinkid;
409                         u8 prio;
410                         u8 tmp;
411                         u32 tmp32;
412                         u8 *cp;
413                         int i;
414                         struct cfctrl_link_param linkparam;
415                         memset(&linkparam, 0, sizeof(linkparam));
416
417                         cfpkt_extr_head(pkt, &tmp, 1);
418
419                         serv = tmp & CFCTRL_SRV_MASK;
420                         linkparam.linktype = serv;
421
422                         servtype = tmp >> 4;
423                         linkparam.chtype = servtype;
424
425                         cfpkt_extr_head(pkt, &tmp, 1);
426                         physlinkid = tmp & 0x07;
427                         prio = tmp >> 3;
428
429                         linkparam.priority = prio;
430                         linkparam.phyid = physlinkid;
431                         cfpkt_extr_head(pkt, &endpoint, 1);
432                         linkparam.endpoint = endpoint & 0x03;
433
434                         switch (serv) {
435                         case CFCTRL_SRV_VEI:
436                         case CFCTRL_SRV_DBG:
437                                 if (CFCTRL_ERR_BIT & cmdrsp)
438                                         break;
439                                 /* Link ID */
440                                 cfpkt_extr_head(pkt, &linkid, 1);
441                                 break;
442                         case CFCTRL_SRV_VIDEO:
443                                 cfpkt_extr_head(pkt, &tmp, 1);
444                                 linkparam.u.video.connid = tmp;
445                                 if (CFCTRL_ERR_BIT & cmdrsp)
446                                         break;
447                                 /* Link ID */
448                                 cfpkt_extr_head(pkt, &linkid, 1);
449                                 break;
450
451                         case CFCTRL_SRV_DATAGRAM:
452                                 cfpkt_extr_head(pkt, &tmp32, 4);
453                                 linkparam.u.datagram.connid =
454                                     le32_to_cpu(tmp32);
455                                 if (CFCTRL_ERR_BIT & cmdrsp)
456                                         break;
457                                 /* Link ID */
458                                 cfpkt_extr_head(pkt, &linkid, 1);
459                                 break;
460                         case CFCTRL_SRV_RFM:
461                                 /* Construct a frame, convert
462                                  * DatagramConnectionID
463                                  * to network format long and copy it out...
464                                  */
465                                 cfpkt_extr_head(pkt, &tmp32, 4);
466                                 linkparam.u.rfm.connid =
467                                   le32_to_cpu(tmp32);
468                                 cp = (u8 *) linkparam.u.rfm.volume;
469                                 for (cfpkt_extr_head(pkt, &tmp, 1);
470                                      cfpkt_more(pkt) && tmp != '\0';
471                                      cfpkt_extr_head(pkt, &tmp, 1))
472                                         *cp++ = tmp;
473                                 *cp = '\0';
474
475                                 if (CFCTRL_ERR_BIT & cmdrsp)
476                                         break;
477                                 /* Link ID */
478                                 cfpkt_extr_head(pkt, &linkid, 1);
479
480                                 break;
481                         case CFCTRL_SRV_UTIL:
482                                 /* Construct a frame, convert
483                                  * DatagramConnectionID
484                                  * to network format long and copy it out...
485                                  */
486                                 /* Fifosize KB */
487                                 cfpkt_extr_head(pkt, &tmp16, 2);
488                                 linkparam.u.utility.fifosize_kb =
489                                     le16_to_cpu(tmp16);
490                                 /* Fifosize bufs */
491                                 cfpkt_extr_head(pkt, &tmp16, 2);
492                                 linkparam.u.utility.fifosize_bufs =
493                                     le16_to_cpu(tmp16);
494                                 /* name */
495                                 cp = (u8 *) linkparam.u.utility.name;
496                                 caif_assert(sizeof(linkparam.u.utility.name)
497                                              >= UTILITY_NAME_LENGTH);
498                                 for (i = 0;
499                                      i < UTILITY_NAME_LENGTH
500                                      && cfpkt_more(pkt); i++) {
501                                         cfpkt_extr_head(pkt, &tmp, 1);
502                                         *cp++ = tmp;
503                                 }
504                                 /* Length */
505                                 cfpkt_extr_head(pkt, &len, 1);
506                                 linkparam.u.utility.paramlen = len;
507                                 /* Param Data */
508                                 cp = linkparam.u.utility.params;
509                                 while (cfpkt_more(pkt) && len--) {
510                                         cfpkt_extr_head(pkt, &tmp, 1);
511                                         *cp++ = tmp;
512                                 }
513                                 if (CFCTRL_ERR_BIT & cmdrsp)
514                                         break;
515                                 /* Link ID */
516                                 cfpkt_extr_head(pkt, &linkid, 1);
517                                 /* Length */
518                                 cfpkt_extr_head(pkt, &len, 1);
519                                 /* Param Data */
520                                 cfpkt_extr_head(pkt, &param, len);
521                                 break;
522                         default:
523                                 pr_warning("CAIF: %s(): Request setup "
524                                            "- invalid link type (%d)",
525                                            __func__, serv);
526                                 goto error;
527                         }
528
529                         rsp.cmd = cmd;
530                         rsp.param = linkparam;
531                         req = cfctrl_remove_req(cfctrl, &rsp);
532
533                         if (CFCTRL_ERR_BIT == (CFCTRL_ERR_BIT & cmdrsp) ||
534                                 cfpkt_erroneous(pkt)) {
535                                 pr_err("CAIF: %s(): Invalid O/E bit or parse "
536                                        "error on CAIF control channel",
537                                         __func__);
538                                 cfctrl->res.reject_rsp(cfctrl->serv.layer.up,
539                                                        0,
540                                                        req ? req->client_layer
541                                                        : NULL);
542                         } else {
543                                 cfctrl->res.linksetup_rsp(cfctrl->serv.
544                                                           layer.up, linkid,
545                                                           serv, physlinkid,
546                                                           req ? req->
547                                                           client_layer : NULL);
548                         }
549
550                         if (req != NULL)
551                                 kfree(req);
552                 }
553                 break;
554         case CFCTRL_CMD_LINK_DESTROY:
555                 cfpkt_extr_head(pkt, &linkid, 1);
556                 cfctrl->res.linkdestroy_rsp(cfctrl->serv.layer.up, linkid);
557                 break;
558         case CFCTRL_CMD_LINK_ERR:
559                 pr_err("CAIF: %s(): Frame Error Indication received\n",
560                         __func__);
561                 cfctrl->res.linkerror_ind();
562                 break;
563         case CFCTRL_CMD_ENUM:
564                 cfctrl->res.enum_rsp();
565                 break;
566         case CFCTRL_CMD_SLEEP:
567                 cfctrl->res.sleep_rsp();
568                 break;
569         case CFCTRL_CMD_WAKE:
570                 cfctrl->res.wake_rsp();
571                 break;
572         case CFCTRL_CMD_LINK_RECONF:
573                 cfctrl->res.restart_rsp();
574                 break;
575         case CFCTRL_CMD_RADIO_SET:
576                 cfctrl->res.radioset_rsp();
577                 break;
578         default:
579                 pr_err("CAIF: %s(): Unrecognized Control Frame\n", __func__);
580                 goto error;
581                 break;
582         }
583         ret = 0;
584 error:
585         cfpkt_destroy(pkt);
586         return ret;
587 }
588
589 static void cfctrl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
590                         int phyid)
591 {
592         struct cfctrl *this = container_obj(layr);
593         switch (ctrl) {
594         case _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND:
595         case CAIF_CTRLCMD_FLOW_OFF_IND:
596                 spin_lock(&this->info_list_lock);
597                 if (!list_empty(&this->list)) {
598                         pr_debug("CAIF: %s(): Received flow off in "
599                                    "control layer", __func__);
600                 }
601                 spin_unlock(&this->info_list_lock);
602                 break;
603         default:
604                 break;
605         }
606 }
607
608 #ifndef CAIF_NO_LOOP
609 static int handle_loop(struct cfctrl *ctrl, int cmd, struct cfpkt *pkt)
610 {
611         static int last_linkid;
612         u8 linkid, linktype, tmp;
613         switch (cmd) {
614         case CFCTRL_CMD_LINK_SETUP:
615                 spin_lock(&ctrl->loop_linkid_lock);
616                 for (linkid = last_linkid + 1; linkid < 255; linkid++)
617                         if (!ctrl->loop_linkused[linkid])
618                                 goto found;
619                 for (linkid = last_linkid - 1; linkid > 0; linkid--)
620                         if (!ctrl->loop_linkused[linkid])
621                                 goto found;
622                 spin_unlock(&ctrl->loop_linkid_lock);
623                 pr_err("CAIF: %s(): Out of link-ids\n", __func__);
624                 return -EINVAL;
625 found:
626                 if (!ctrl->loop_linkused[linkid])
627                         ctrl->loop_linkused[linkid] = 1;
628
629                 last_linkid = linkid;
630
631                 cfpkt_add_trail(pkt, &linkid, 1);
632                 spin_unlock(&ctrl->loop_linkid_lock);
633                 cfpkt_peek_head(pkt, &linktype, 1);
634                 if (linktype ==  CFCTRL_SRV_UTIL) {
635                         tmp = 0x01;
636                         cfpkt_add_trail(pkt, &tmp, 1);
637                         cfpkt_add_trail(pkt, &tmp, 1);
638                 }
639                 break;
640
641         case CFCTRL_CMD_LINK_DESTROY:
642                 spin_lock(&ctrl->loop_linkid_lock);
643                 cfpkt_peek_head(pkt, &linkid, 1);
644                 ctrl->loop_linkused[linkid] = 0;
645                 spin_unlock(&ctrl->loop_linkid_lock);
646                 break;
647         default:
648                 break;
649         }
650         return CAIF_SUCCESS;
651 }
652 #endif