root/drivers/staging/uwb/drp.c

DEFINITIONS

1. uwb_rc_set_drp_cmd_done
2. uwb_rc_send_all_drp_ie
3. evaluate_conflict_action
4. handle_conflict_normal
5. handle_conflict_expanding
6. uwb_drp_handle_conflict_rsv
7. uwb_drp_handle_all_conflict_rsv
8. uwb_drp_process_target_accepted
9. uwb_drp_process_target
10. uwb_drp_process_owner_accepted
11. uwb_drp_process_owner
12. uwb_cnflt_alien_stroke_timer
13. uwb_cnflt_update_work
14. uwb_cnflt_timer
15. uwb_drp_handle_alien_drp
16. uwb_drp_process_not_involved
17. uwb_drp_process_involved
18. uwb_drp_involves_us
19. uwb_drp_process
20. uwb_drp_availability_process
21. uwb_drp_process_all
22. uwbd_evt_handle_rc_drp

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Ultra Wide Band
   4  * Dynamic Reservation Protocol handling
   5  *
   6  * Copyright (C) 2005-2006 Intel Corporation
   7  * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
   8  * Copyright (C) 2008 Cambridge Silicon Radio Ltd.
   9  */
  10 #include <linux/kthread.h>
  11 #include <linux/freezer.h>
  12 #include <linux/slab.h>
  13 #include <linux/delay.h>
  14 #include "uwb-internal.h"
  15 
  16 
  17 /* DRP Conflict Actions ([ECMA-368 2nd Edition] 17.4.6) */
  18 enum uwb_drp_conflict_action {
  19         /* Reservation is maintained, no action needed */
  20         UWB_DRP_CONFLICT_MANTAIN = 0,
  21 
  22         /* the device shall not transmit frames in conflicting MASs in
  23          * the following superframe. If the device is the reservation
  24          * target, it shall also set the Reason Code in its DRP IE to
  25          * Conflict in its beacon in the following superframe.
  26          */
  27         UWB_DRP_CONFLICT_ACT1,
  28 
  29         /* the device shall not set the Reservation Status bit to ONE
  30          * and shall not transmit frames in conflicting MASs. If the
  31          * device is the reservation target, it shall also set the
  32          * Reason Code in its DRP IE to Conflict.
  33          */
  34         UWB_DRP_CONFLICT_ACT2,
  35 
  36         /* the device shall not transmit frames in conflicting MASs in
  37          * the following superframe. It shall remove the conflicting
  38          * MASs from the reservation or set the Reservation Status to
  39          * ZERO in its beacon in the following superframe. If the
  40          * device is the reservation target, it shall also set the
  41          * Reason Code in its DRP IE to Conflict.
  42          */
  43         UWB_DRP_CONFLICT_ACT3,
  44 };
  45 
  46 
  47 static void uwb_rc_set_drp_cmd_done(struct uwb_rc *rc, void *arg,
  48                                     struct uwb_rceb *reply, ssize_t reply_size)
  49 {
  50         struct uwb_rc_evt_set_drp_ie *r = (struct uwb_rc_evt_set_drp_ie *)reply;
  51         unsigned long flags;
  52 
  53         if (r != NULL) {
  54                 if (r->bResultCode != UWB_RC_RES_SUCCESS)
  55                         dev_err(&rc->uwb_dev.dev, "SET-DRP-IE failed: %s (%d)\n",
  56                                 uwb_rc_strerror(r->bResultCode), r->bResultCode);
  57         } else
  58                 dev_err(&rc->uwb_dev.dev, "SET-DRP-IE: timeout\n");
  59 
  60         spin_lock_irqsave(&rc->rsvs_lock, flags);
  61         if (rc->set_drp_ie_pending > 1) {
  62                 rc->set_drp_ie_pending = 0;
  63                 uwb_rsv_queue_update(rc);
  64         } else {
  65                 rc->set_drp_ie_pending = 0;
  66         }
  67         spin_unlock_irqrestore(&rc->rsvs_lock, flags);
  68 }
  69 
  70 /**
  71  * Construct and send the SET DRP IE
  72  *
  73  * @rc:         UWB Host controller
  74  * @returns:    >= 0 number of bytes still available in the beacon
  75  *              < 0 errno code on error.
  76  *
  77  * See WUSB[8.6.2.7]: The host must set all the DRP IEs that it wants the
  78  * device to include in its beacon at the same time. We thus have to
  79  * traverse all reservations and include the DRP IEs of all PENDING
  80  * and NEGOTIATED reservations in a SET DRP command for transmission.
  81  *
  82  * A DRP Availability IE is appended.
  83  *
  84  * rc->rsvs_mutex is held
  85  *
  86  * FIXME We currently ignore the returned value indicating the remaining space
  87  * in beacon. This could be used to deny reservation requests earlier if
  88  * determined that they would cause the beacon space to be exceeded.
  89  */
  90 int uwb_rc_send_all_drp_ie(struct uwb_rc *rc)
  91 {
  92         int result;
  93         struct uwb_rc_cmd_set_drp_ie *cmd;
  94         struct uwb_rsv *rsv;
  95         struct uwb_rsv_move *mv;
  96         int num_bytes = 0;
  97         u8 *IEDataptr;
  98 
  99         result = -ENOMEM;
 100         /* First traverse all reservations to determine memory needed. */
 101         list_for_each_entry(rsv, &rc->reservations, rc_node) {
 102                 if (rsv->drp_ie != NULL) {
 103                         num_bytes += rsv->drp_ie->hdr.length + 2;
 104                         if (uwb_rsv_has_two_drp_ies(rsv) &&
 105                                 (rsv->mv.companion_drp_ie != NULL)) {
 106                                 mv = &rsv->mv;
 107                                 num_bytes +=
 108                                         mv->companion_drp_ie->hdr.length + 2;
 109                         }
 110                 }
 111         }
 112         num_bytes += sizeof(rc->drp_avail.ie);
 113         cmd = kzalloc(sizeof(*cmd) + num_bytes, GFP_KERNEL);
 114         if (cmd == NULL)
 115                 goto error;
 116         cmd->rccb.bCommandType = UWB_RC_CET_GENERAL;
 117         cmd->rccb.wCommand = cpu_to_le16(UWB_RC_CMD_SET_DRP_IE);
 118         cmd->wIELength = num_bytes;
 119         IEDataptr = (u8 *)&cmd->IEData[0];
 120 
 121         /* FIXME: DRV avail IE is not always needed */
 122         /* put DRP avail IE first */
 123         memcpy(IEDataptr, &rc->drp_avail.ie, sizeof(rc->drp_avail.ie));
 124         IEDataptr += sizeof(struct uwb_ie_drp_avail);
 125 
 126         /* Next traverse all reservations to place IEs in allocated memory. */
 127         list_for_each_entry(rsv, &rc->reservations, rc_node) {
 128                 if (rsv->drp_ie != NULL) {
 129                         memcpy(IEDataptr, rsv->drp_ie,
 130                                rsv->drp_ie->hdr.length + 2);
 131                         IEDataptr += rsv->drp_ie->hdr.length + 2;
 132 
 133                         if (uwb_rsv_has_two_drp_ies(rsv) &&
 134                                 (rsv->mv.companion_drp_ie != NULL)) {
 135                                 mv = &rsv->mv;
 136                                 memcpy(IEDataptr, mv->companion_drp_ie,
 137                                        mv->companion_drp_ie->hdr.length + 2);
 138                                 IEDataptr +=
 139                                         mv->companion_drp_ie->hdr.length + 2;
 140                         }
 141                 }
 142         }
 143 
 144         result = uwb_rc_cmd_async(rc, "SET-DRP-IE",
 145                                 &cmd->rccb, sizeof(*cmd) + num_bytes,
 146                                 UWB_RC_CET_GENERAL, UWB_RC_CMD_SET_DRP_IE,
 147                                 uwb_rc_set_drp_cmd_done, NULL);
 148 
 149         rc->set_drp_ie_pending = 1;
 150 
 151         kfree(cmd);
 152 error:
 153         return result;
 154 }
 155 
 156 /*
 157  * Evaluate the action to perform using conflict resolution rules
 158  *
 159  * Return a uwb_drp_conflict_action.
 160  */
 161 static int evaluate_conflict_action(struct uwb_ie_drp *ext_drp_ie, int ext_beacon_slot,
 162                                     struct uwb_rsv *rsv, int our_status)
 163 {
 164         int our_tie_breaker = rsv->tiebreaker;
 165         int our_type        = rsv->type;
 166         int our_beacon_slot = rsv->rc->uwb_dev.beacon_slot;
 167 
 168         int ext_tie_breaker = uwb_ie_drp_tiebreaker(ext_drp_ie);
 169         int ext_status      = uwb_ie_drp_status(ext_drp_ie);
 170         int ext_type        = uwb_ie_drp_type(ext_drp_ie);
 171 
 172 
 173         /* [ECMA-368 2nd Edition] 17.4.6 */
 174         if (ext_type == UWB_DRP_TYPE_PCA && our_type == UWB_DRP_TYPE_PCA) {
 175                 return UWB_DRP_CONFLICT_MANTAIN;
 176         }
 177 
 178         /* [ECMA-368 2nd Edition] 17.4.6-1 */
 179         if (our_type == UWB_DRP_TYPE_ALIEN_BP) {
 180                 return UWB_DRP_CONFLICT_MANTAIN;
 181         }
 182 
 183         /* [ECMA-368 2nd Edition] 17.4.6-2 */
 184         if (ext_type == UWB_DRP_TYPE_ALIEN_BP) {
 185                 /* here we know our_type != UWB_DRP_TYPE_ALIEN_BP */
 186                 return UWB_DRP_CONFLICT_ACT1;
 187         }
 188 
 189         /* [ECMA-368 2nd Edition] 17.4.6-3 */
 190         if (our_status == 0 && ext_status == 1) {
 191                 return UWB_DRP_CONFLICT_ACT2;
 192         }
 193 
 194         /* [ECMA-368 2nd Edition] 17.4.6-4 */
 195         if (our_status == 1 && ext_status == 0) {
 196                 return UWB_DRP_CONFLICT_MANTAIN;
 197         }
 198 
 199         /* [ECMA-368 2nd Edition] 17.4.6-5a */
 200         if (our_tie_breaker == ext_tie_breaker &&
 201             our_beacon_slot <  ext_beacon_slot) {
 202                 return UWB_DRP_CONFLICT_MANTAIN;
 203         }
 204 
 205         /* [ECMA-368 2nd Edition] 17.4.6-5b */
 206         if (our_tie_breaker != ext_tie_breaker &&
 207             our_beacon_slot >  ext_beacon_slot) {
 208                 return UWB_DRP_CONFLICT_MANTAIN;
 209         }
 210 
 211         if (our_status == 0) {
 212                 if (our_tie_breaker == ext_tie_breaker) {
 213                         /* [ECMA-368 2nd Edition] 17.4.6-6a */
 214                         if (our_beacon_slot > ext_beacon_slot) {
 215                                 return UWB_DRP_CONFLICT_ACT2;
 216                         }
 217                 } else  {
 218                         /* [ECMA-368 2nd Edition] 17.4.6-6b */
 219                         if (our_beacon_slot < ext_beacon_slot) {
 220                                 return UWB_DRP_CONFLICT_ACT2;
 221                         }
 222                 }
 223         } else {
 224                 if (our_tie_breaker == ext_tie_breaker) {
 225                         /* [ECMA-368 2nd Edition] 17.4.6-7a */
 226                         if (our_beacon_slot > ext_beacon_slot) {
 227                                 return UWB_DRP_CONFLICT_ACT3;
 228                         }
 229                 } else {
 230                         /* [ECMA-368 2nd Edition] 17.4.6-7b */
 231                         if (our_beacon_slot < ext_beacon_slot) {
 232                                 return UWB_DRP_CONFLICT_ACT3;
 233                         }
 234                 }
 235         }
 236         return UWB_DRP_CONFLICT_MANTAIN;
 237 }
 238 
 239 static void handle_conflict_normal(struct uwb_ie_drp *drp_ie,
 240                                    int ext_beacon_slot,
 241                                    struct uwb_rsv *rsv,
 242                                    struct uwb_mas_bm *conflicting_mas)
 243 {
 244         struct uwb_rc *rc = rsv->rc;
 245         struct uwb_rsv_move *mv = &rsv->mv;
 246         struct uwb_drp_backoff_win *bow = &rc->bow;
 247         int action;
 248 
 249         action = evaluate_conflict_action(drp_ie, ext_beacon_slot, rsv, uwb_rsv_status(rsv));
 250 
 251         if (uwb_rsv_is_owner(rsv)) {
 252                 switch(action) {
 253                 case UWB_DRP_CONFLICT_ACT2:
 254                         /* try move */
 255                         uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_TO_BE_MOVED);
 256                         if (bow->can_reserve_extra_mases == false)
 257                                 uwb_rsv_backoff_win_increment(rc);
 258 
 259                         break;
 260                 case UWB_DRP_CONFLICT_ACT3:
 261                         uwb_rsv_backoff_win_increment(rc);
 262                         /* drop some mases with reason modified */
 263                         /* put in the companion the mases to be dropped */
 264                         bitmap_and(mv->companion_mas.bm, rsv->mas.bm, conflicting_mas->bm, UWB_NUM_MAS);
 265                         uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_MODIFIED);
 266                 default:
 267                         break;
 268                 }
 269         } else {
 270                 switch(action) {
 271                 case UWB_DRP_CONFLICT_ACT2:
 272                 case UWB_DRP_CONFLICT_ACT3:
 273                         uwb_rsv_set_state(rsv, UWB_RSV_STATE_T_CONFLICT);
 274                 default:
 275                         break;
 276                 }
 277 
 278         }
 279 
 280 }
 281 
 282 static void handle_conflict_expanding(struct uwb_ie_drp *drp_ie, int ext_beacon_slot,
 283                                       struct uwb_rsv *rsv, bool companion_only,
 284                                       struct uwb_mas_bm *conflicting_mas)
 285 {
 286         struct uwb_rc *rc = rsv->rc;
 287         struct uwb_drp_backoff_win *bow = &rc->bow;
 288         struct uwb_rsv_move *mv = &rsv->mv;
 289         int action;
 290 
 291         if (companion_only) {
 292                 /* status of companion is 0 at this point */
 293                 action = evaluate_conflict_action(drp_ie, ext_beacon_slot, rsv, 0);
 294                 if (uwb_rsv_is_owner(rsv)) {
 295                         switch(action) {
 296                         case UWB_DRP_CONFLICT_ACT2:
 297                         case UWB_DRP_CONFLICT_ACT3:
 298                                 uwb_rsv_set_state(rsv,
 299                                                 UWB_RSV_STATE_O_ESTABLISHED);
 300                                 rsv->needs_release_companion_mas = false;
 301                                 if (bow->can_reserve_extra_mases == false)
 302                                         uwb_rsv_backoff_win_increment(rc);
 303                                 uwb_drp_avail_release(rsv->rc,
 304                                                 &rsv->mv.companion_mas);
 305                         }
 306                 } else { /* rsv is target */
 307                         switch(action) {
 308                         case UWB_DRP_CONFLICT_ACT2:
 309                         case UWB_DRP_CONFLICT_ACT3:
 310                                 uwb_rsv_set_state(rsv,
 311                                         UWB_RSV_STATE_T_EXPANDING_CONFLICT);
 312                                 /* send_drp_avail_ie = true; */
 313                         }
 314                 }
 315         } else { /* also base part of the reservation is conflicting */
 316                 if (uwb_rsv_is_owner(rsv)) {
 317                         uwb_rsv_backoff_win_increment(rc);
 318                         /* remove companion part */
 319                         uwb_drp_avail_release(rsv->rc, &rsv->mv.companion_mas);
 320 
 321                         /* drop some mases with reason modified */
 322 
 323                         /* put in the companion the mases to be dropped */
 324                         bitmap_andnot(mv->companion_mas.bm, rsv->mas.bm,
 325                                         conflicting_mas->bm, UWB_NUM_MAS);
 326                         uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_MODIFIED);
 327                 } else { /* it is a target rsv */
 328                         uwb_rsv_set_state(rsv, UWB_RSV_STATE_T_CONFLICT);
 329                         /* send_drp_avail_ie = true; */
 330                 }
 331         }
 332 }
 333 
 334 static void uwb_drp_handle_conflict_rsv(struct uwb_rc *rc, struct uwb_rsv *rsv,
 335                                         struct uwb_rc_evt_drp *drp_evt,
 336                                         struct uwb_ie_drp *drp_ie,
 337                                         struct uwb_mas_bm *conflicting_mas)
 338 {
 339         struct uwb_rsv_move *mv;
 340 
 341         /* check if the conflicting reservation has two drp_ies */
 342         if (uwb_rsv_has_two_drp_ies(rsv)) {
 343                 mv = &rsv->mv;
 344                 if (bitmap_intersects(rsv->mas.bm, conflicting_mas->bm,
 345                                                                 UWB_NUM_MAS)) {
 346                         handle_conflict_expanding(drp_ie,
 347                                                 drp_evt->beacon_slot_number,
 348                                                 rsv, false, conflicting_mas);
 349                 } else {
 350                         if (bitmap_intersects(mv->companion_mas.bm,
 351                                         conflicting_mas->bm, UWB_NUM_MAS)) {
 352                                 handle_conflict_expanding(
 353                                         drp_ie, drp_evt->beacon_slot_number,
 354                                         rsv, true, conflicting_mas);
 355                         }
 356                 }
 357         } else if (bitmap_intersects(rsv->mas.bm, conflicting_mas->bm,
 358                                                         UWB_NUM_MAS)) {
 359                 handle_conflict_normal(drp_ie, drp_evt->beacon_slot_number,
 360                                         rsv, conflicting_mas);
 361         }
 362 }
 363 
 364 static void uwb_drp_handle_all_conflict_rsv(struct uwb_rc *rc,
 365                                             struct uwb_rc_evt_drp *drp_evt,
 366                                             struct uwb_ie_drp *drp_ie,
 367                                             struct uwb_mas_bm *conflicting_mas)
 368 {
 369         struct uwb_rsv *rsv;
 370 
 371         list_for_each_entry(rsv, &rc->reservations, rc_node) {
 372                 uwb_drp_handle_conflict_rsv(rc, rsv, drp_evt, drp_ie,
 373                                                         conflicting_mas);
 374         }
 375 }
 376 
 377 static void uwb_drp_process_target_accepted(struct uwb_rc *rc,
 378         struct uwb_rsv *rsv, struct uwb_rc_evt_drp *drp_evt,
 379         struct uwb_ie_drp *drp_ie, struct uwb_mas_bm *mas)
 380 {
 381         struct uwb_rsv_move *mv = &rsv->mv;
 382         int status;
 383 
 384         status = uwb_ie_drp_status(drp_ie);
 385 
 386         if (rsv->state == UWB_RSV_STATE_T_CONFLICT) {
 387                 uwb_rsv_set_state(rsv, UWB_RSV_STATE_T_CONFLICT);
 388                 return;
 389         }
 390 
 391         if (rsv->state == UWB_RSV_STATE_T_EXPANDING_ACCEPTED) {
 392                 /* drp_ie is companion */
 393                 if (!bitmap_equal(rsv->mas.bm, mas->bm, UWB_NUM_MAS)) {
 394                         /* stroke companion */
 395                         uwb_rsv_set_state(rsv,
 396                                 UWB_RSV_STATE_T_EXPANDING_ACCEPTED);
 397                 }
 398         } else {
 399                 if (!bitmap_equal(rsv->mas.bm, mas->bm, UWB_NUM_MAS)) {
 400                         if (uwb_drp_avail_reserve_pending(rc, mas) == -EBUSY) {
 401                                 /* FIXME: there is a conflict, find
 402                                  * the conflicting reservations and
 403                                  * take a sensible action. Consider
 404                                  * that in drp_ie there is the
 405                                  * "neighbour" */
 406                                 uwb_drp_handle_all_conflict_rsv(rc, drp_evt,
 407                                                 drp_ie, mas);
 408                         } else {
 409                                 /* accept the extra reservation */
 410                                 bitmap_copy(mv->companion_mas.bm, mas->bm,
 411                                                                 UWB_NUM_MAS);
 412                                 uwb_rsv_set_state(rsv,
 413                                         UWB_RSV_STATE_T_EXPANDING_ACCEPTED);
 414                         }
 415                 } else {
 416                         if (status) {
 417                                 uwb_rsv_set_state(rsv,
 418                                                 UWB_RSV_STATE_T_ACCEPTED);
 419                         }
 420                 }
 421 
 422         }
 423 }
 424 
 425 /*
 426  * Based on the DRP IE, transition a target reservation to a new
 427  * state.
 428  */
 429 static void uwb_drp_process_target(struct uwb_rc *rc, struct uwb_rsv *rsv,
 430                    struct uwb_ie_drp *drp_ie, struct uwb_rc_evt_drp *drp_evt)
 431 {
 432         struct device *dev = &rc->uwb_dev.dev;
 433         struct uwb_rsv_move *mv = &rsv->mv;
 434         int status;
 435         enum uwb_drp_reason reason_code;
 436         struct uwb_mas_bm mas;
 437 
 438         status = uwb_ie_drp_status(drp_ie);
 439         reason_code = uwb_ie_drp_reason_code(drp_ie);
 440         uwb_drp_ie_to_bm(&mas, drp_ie);
 441 
 442         switch (reason_code) {
 443         case UWB_DRP_REASON_ACCEPTED:
 444                 uwb_drp_process_target_accepted(rc, rsv, drp_evt, drp_ie, &mas);
 445                 break;
 446 
 447         case UWB_DRP_REASON_MODIFIED:
 448                 /* check to see if we have already modified the reservation */
 449                 if (bitmap_equal(rsv->mas.bm, mas.bm, UWB_NUM_MAS)) {
 450                         uwb_rsv_set_state(rsv, UWB_RSV_STATE_T_ACCEPTED);
 451                         break;
 452                 }
 453 
 454                 /* find if the owner wants to expand or reduce */
 455                 if (bitmap_subset(mas.bm, rsv->mas.bm, UWB_NUM_MAS)) {
 456                         /* owner is reducing */
 457                         bitmap_andnot(mv->companion_mas.bm, rsv->mas.bm, mas.bm,
 458                                 UWB_NUM_MAS);
 459                         uwb_drp_avail_release(rsv->rc, &mv->companion_mas);
 460                 }
 461 
 462                 bitmap_copy(rsv->mas.bm, mas.bm, UWB_NUM_MAS);
 463                 uwb_rsv_set_state(rsv, UWB_RSV_STATE_T_RESIZED);
 464                 break;
 465         default:
 466                 dev_warn(dev, "ignoring invalid DRP IE state (%d/%d)\n",
 467                          reason_code, status);
 468         }
 469 }
 470 
 471 static void uwb_drp_process_owner_accepted(struct uwb_rsv *rsv,
 472                                                 struct uwb_mas_bm *mas)
 473 {
 474         struct uwb_rsv_move *mv = &rsv->mv;
 475 
 476         switch (rsv->state) {
 477         case UWB_RSV_STATE_O_PENDING:
 478         case UWB_RSV_STATE_O_INITIATED:
 479         case UWB_RSV_STATE_O_ESTABLISHED:
 480                 uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_ESTABLISHED);
 481                 break;
 482         case UWB_RSV_STATE_O_MODIFIED:
 483                 if (bitmap_equal(mas->bm, rsv->mas.bm, UWB_NUM_MAS))
 484                         uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_ESTABLISHED);
 485                 else
 486                         uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_MODIFIED);
 487                 break;
 488 
 489         case UWB_RSV_STATE_O_MOVE_REDUCING: /* shouldn' t be a problem */
 490                 if (bitmap_equal(mas->bm, rsv->mas.bm, UWB_NUM_MAS))
 491                         uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_ESTABLISHED);
 492                 else
 493                         uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_MOVE_REDUCING);
 494                 break;
 495         case UWB_RSV_STATE_O_MOVE_EXPANDING:
 496                 if (bitmap_equal(mas->bm, mv->companion_mas.bm, UWB_NUM_MAS)) {
 497                         /* Companion reservation accepted */
 498                         uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_MOVE_COMBINING);
 499                 } else {
 500                         uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_MOVE_EXPANDING);
 501                 }
 502                 break;
 503         case UWB_RSV_STATE_O_MOVE_COMBINING:
 504                 if (bitmap_equal(mas->bm, rsv->mas.bm, UWB_NUM_MAS))
 505                         uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_MOVE_REDUCING);
 506                 else
 507                         uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_MOVE_COMBINING);
 508                 break;
 509         default:
 510                 break;
 511         }
 512 }
 513 /*
 514  * Based on the DRP IE, transition an owner reservation to a new
 515  * state.
 516  */
 517 static void uwb_drp_process_owner(struct uwb_rc *rc, struct uwb_rsv *rsv,
 518                                   struct uwb_dev *src, struct uwb_ie_drp *drp_ie,
 519                                   struct uwb_rc_evt_drp *drp_evt)
 520 {
 521         struct device *dev = &rc->uwb_dev.dev;
 522         int status;
 523         enum uwb_drp_reason reason_code;
 524         struct uwb_mas_bm mas;
 525 
 526         status = uwb_ie_drp_status(drp_ie);
 527         reason_code = uwb_ie_drp_reason_code(drp_ie);
 528         uwb_drp_ie_to_bm(&mas, drp_ie);
 529 
 530         if (status) {
 531                 switch (reason_code) {
 532                 case UWB_DRP_REASON_ACCEPTED:
 533                         uwb_drp_process_owner_accepted(rsv, &mas);
 534                         break;
 535                 default:
 536                         dev_warn(dev, "ignoring invalid DRP IE state (%d/%d)\n",
 537                                  reason_code, status);
 538                 }
 539         } else {
 540                 switch (reason_code) {
 541                 case UWB_DRP_REASON_PENDING:
 542                         uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_PENDING);
 543                         break;
 544                 case UWB_DRP_REASON_DENIED:
 545                         uwb_rsv_set_state(rsv, UWB_RSV_STATE_NONE);
 546                         break;
 547                 case UWB_DRP_REASON_CONFLICT:
 548                         /* resolve the conflict */
 549                         bitmap_complement(mas.bm, src->last_availability_bm,
 550                                           UWB_NUM_MAS);
 551                         uwb_drp_handle_conflict_rsv(rc, rsv, drp_evt, drp_ie, &mas);
 552                         break;
 553                 default:
 554                         dev_warn(dev, "ignoring invalid DRP IE state (%d/%d)\n",
 555                                  reason_code, status);
 556                 }
 557         }
 558 }
 559 
 560 static void uwb_cnflt_alien_stroke_timer(struct uwb_cnflt_alien *cnflt)
 561 {
 562         unsigned timeout_us = UWB_MAX_LOST_BEACONS * UWB_SUPERFRAME_LENGTH_US;
 563         mod_timer(&cnflt->timer, jiffies + usecs_to_jiffies(timeout_us));
 564 }
 565 
 566 static void uwb_cnflt_update_work(struct work_struct *work)
 567 {
 568         struct uwb_cnflt_alien *cnflt = container_of(work,
 569                                                      struct uwb_cnflt_alien,
 570                                                      cnflt_update_work);
 571         struct uwb_cnflt_alien *c;
 572         struct uwb_rc *rc = cnflt->rc;
 573 
 574         unsigned long delay_us = UWB_MAS_LENGTH_US * UWB_MAS_PER_ZONE;
 575 
 576         mutex_lock(&rc->rsvs_mutex);
 577 
 578         list_del(&cnflt->rc_node);
 579 
 580         /* update rc global conflicting alien bitmap */
 581         bitmap_zero(rc->cnflt_alien_bitmap.bm, UWB_NUM_MAS);
 582 
 583         list_for_each_entry(c, &rc->cnflt_alien_list, rc_node) {
 584                 bitmap_or(rc->cnflt_alien_bitmap.bm, rc->cnflt_alien_bitmap.bm,
 585                                                 c->mas.bm, UWB_NUM_MAS);
 586         }
 587 
 588         queue_delayed_work(rc->rsv_workq, &rc->rsv_alien_bp_work,
 589                                         usecs_to_jiffies(delay_us));
 590 
 591         kfree(cnflt);
 592         mutex_unlock(&rc->rsvs_mutex);
 593 }
 594 
 595 static void uwb_cnflt_timer(struct timer_list *t)
 596 {
 597         struct uwb_cnflt_alien *cnflt = from_timer(cnflt, t, timer);
 598 
 599         queue_work(cnflt->rc->rsv_workq, &cnflt->cnflt_update_work);
 600 }
 601 
 602 /*
 603  * We have received an DRP_IE of type Alien BP and we need to make
 604  * sure we do not transmit in conflicting MASs.
 605  */
 606 static void uwb_drp_handle_alien_drp(struct uwb_rc *rc, struct uwb_ie_drp *drp_ie)
 607 {
 608         struct device *dev = &rc->uwb_dev.dev;
 609         struct uwb_mas_bm mas;
 610         struct uwb_cnflt_alien *cnflt;
 611         unsigned long delay_us = UWB_MAS_LENGTH_US * UWB_MAS_PER_ZONE;
 612 
 613         uwb_drp_ie_to_bm(&mas, drp_ie);
 614 
 615         list_for_each_entry(cnflt, &rc->cnflt_alien_list, rc_node) {
 616                 if (bitmap_equal(cnflt->mas.bm, mas.bm, UWB_NUM_MAS)) {
 617                         /* Existing alien BP reservation conflicting
 618                          * bitmap, just reset the timer */
 619                         uwb_cnflt_alien_stroke_timer(cnflt);
 620                         return;
 621                 }
 622         }
 623 
 624         /* New alien BP reservation conflicting bitmap */
 625 
 626         /* alloc and initialize new uwb_cnflt_alien */
 627         cnflt = kzalloc(sizeof(struct uwb_cnflt_alien), GFP_KERNEL);
 628         if (!cnflt) {
 629                 dev_err(dev, "failed to alloc uwb_cnflt_alien struct\n");
 630                 return;
 631         }
 632 
 633         INIT_LIST_HEAD(&cnflt->rc_node);
 634         timer_setup(&cnflt->timer, uwb_cnflt_timer, 0);
 635 
 636         cnflt->rc = rc;
 637         INIT_WORK(&cnflt->cnflt_update_work, uwb_cnflt_update_work);
 638 
 639         bitmap_copy(cnflt->mas.bm, mas.bm, UWB_NUM_MAS);
 640 
 641         list_add_tail(&cnflt->rc_node, &rc->cnflt_alien_list);
 642 
 643         /* update rc global conflicting alien bitmap */
 644         bitmap_or(rc->cnflt_alien_bitmap.bm, rc->cnflt_alien_bitmap.bm, mas.bm, UWB_NUM_MAS);
 645 
 646         queue_delayed_work(rc->rsv_workq, &rc->rsv_alien_bp_work, usecs_to_jiffies(delay_us));
 647 
 648         /* start the timer */
 649         uwb_cnflt_alien_stroke_timer(cnflt);
 650 }
 651 
 652 static void uwb_drp_process_not_involved(struct uwb_rc *rc,
 653                                          struct uwb_rc_evt_drp *drp_evt,
 654                                          struct uwb_ie_drp *drp_ie)
 655 {
 656         struct uwb_mas_bm mas;
 657 
 658         uwb_drp_ie_to_bm(&mas, drp_ie);
 659         uwb_drp_handle_all_conflict_rsv(rc, drp_evt, drp_ie, &mas);
 660 }
 661 
 662 static void uwb_drp_process_involved(struct uwb_rc *rc, struct uwb_dev *src,
 663                                      struct uwb_rc_evt_drp *drp_evt,
 664                                      struct uwb_ie_drp *drp_ie)
 665 {
 666         struct uwb_rsv *rsv;
 667 
 668         rsv = uwb_rsv_find(rc, src, drp_ie);
 669         if (!rsv) {
 670                 /*
 671                  * No reservation? It's either for a recently
 672                  * terminated reservation; or the DRP IE couldn't be
 673                  * processed (e.g., an invalid IE or out of memory).
 674                  */
 675                 return;
 676         }
 677 
 678         /*
 679          * Do nothing with DRP IEs for reservations that have been
 680          * terminated.
 681          */
 682         if (rsv->state == UWB_RSV_STATE_NONE) {
 683                 uwb_rsv_set_state(rsv, UWB_RSV_STATE_NONE);
 684                 return;
 685         }
 686 
 687         if (uwb_ie_drp_owner(drp_ie))
 688                 uwb_drp_process_target(rc, rsv, drp_ie, drp_evt);
 689         else
 690                 uwb_drp_process_owner(rc, rsv, src, drp_ie, drp_evt);
 691 
 692 }
 693 
 694 
 695 static bool uwb_drp_involves_us(struct uwb_rc *rc, struct uwb_ie_drp *drp_ie)
 696 {
 697         return uwb_dev_addr_cmp(&rc->uwb_dev.dev_addr, &drp_ie->dev_addr) == 0;
 698 }
 699 
 700 /*
 701  * Process a received DRP IE.
 702  */
 703 static void uwb_drp_process(struct uwb_rc *rc, struct uwb_rc_evt_drp *drp_evt,
 704                             struct uwb_dev *src, struct uwb_ie_drp *drp_ie)
 705 {
 706         if (uwb_ie_drp_type(drp_ie) == UWB_DRP_TYPE_ALIEN_BP)
 707                 uwb_drp_handle_alien_drp(rc, drp_ie);
 708         else if (uwb_drp_involves_us(rc, drp_ie))
 709                 uwb_drp_process_involved(rc, src, drp_evt, drp_ie);
 710         else
 711                 uwb_drp_process_not_involved(rc, drp_evt, drp_ie);
 712 }
 713 
 714 /*
 715  * Process a received DRP Availability IE
 716  */
 717 static void uwb_drp_availability_process(struct uwb_rc *rc, struct uwb_dev *src,
 718                                          struct uwb_ie_drp_avail *drp_availability_ie)
 719 {
 720         bitmap_copy(src->last_availability_bm,
 721                     drp_availability_ie->bmp, UWB_NUM_MAS);
 722 }
 723 
 724 /*
 725  * Process all the DRP IEs (both DRP IEs and the DRP Availability IE)
 726  * from a device.
 727  */
 728 static
 729 void uwb_drp_process_all(struct uwb_rc *rc, struct uwb_rc_evt_drp *drp_evt,
 730                          size_t ielen, struct uwb_dev *src_dev)
 731 {
 732         struct device *dev = &rc->uwb_dev.dev;
 733         struct uwb_ie_hdr *ie_hdr;
 734         void *ptr;
 735 
 736         ptr = drp_evt->ie_data;
 737         for (;;) {
 738                 ie_hdr = uwb_ie_next(&ptr, &ielen);
 739                 if (!ie_hdr)
 740                         break;
 741 
 742                 switch (ie_hdr->element_id) {
 743                 case UWB_IE_DRP_AVAILABILITY:
 744                         uwb_drp_availability_process(rc, src_dev, (struct uwb_ie_drp_avail *)ie_hdr);
 745                         break;
 746                 case UWB_IE_DRP:
 747                         uwb_drp_process(rc, drp_evt, src_dev, (struct uwb_ie_drp *)ie_hdr);
 748                         break;
 749                 default:
 750                         dev_warn(dev, "unexpected IE in DRP notification\n");
 751                         break;
 752                 }
 753         }
 754 
 755         if (ielen > 0)
 756                 dev_warn(dev, "%d octets remaining in DRP notification\n",
 757                          (int)ielen);
 758 }
 759 
 760 /**
 761  * uwbd_evt_handle_rc_drp - handle a DRP_IE event
 762  * @evt: the DRP_IE event from the radio controller
 763  *
 764  * This processes DRP notifications from the radio controller, either
 765  * initiating a new reservation or transitioning an existing
 766  * reservation into a different state.
 767  *
 768  * DRP notifications can occur for three different reasons:
 769  *
 770  * - UWB_DRP_NOTIF_DRP_IE_RECVD: one or more DRP IEs with the RC as
 771  *   the target or source have been received.
 772  *
 773  *   These DRP IEs could be new or for an existing reservation.
 774  *
 775  *   If the DRP IE for an existing reservation ceases to be to
 776  *   received for at least mMaxLostBeacons, the reservation should be
 777  *   considered to be terminated.  Note that the TERMINATE reason (see
 778  *   below) may not always be signalled (e.g., the remote device has
 779  *   two or more reservations established with the RC).
 780  *
 781  * - UWB_DRP_NOTIF_CONFLICT: DRP IEs from any device in the beacon
 782  *   group conflict with the RC's reservations.
 783  *
 784  * - UWB_DRP_NOTIF_TERMINATE: DRP IEs are no longer being received
 785  *   from a device (i.e., it's terminated all reservations).
 786  *
 787  * Only the software state of the reservations is changed; the setting
 788  * of the radio controller's DRP IEs is done after all the events in
 789  * an event buffer are processed.  This saves waiting multiple times
 790  * for the SET_DRP_IE command to complete.
 791  */
 792 int uwbd_evt_handle_rc_drp(struct uwb_event *evt)
 793 {
 794         struct device *dev = &evt->rc->uwb_dev.dev;
 795         struct uwb_rc *rc = evt->rc;
 796         struct uwb_rc_evt_drp *drp_evt;
 797         size_t ielength, bytes_left;
 798         struct uwb_dev_addr src_addr;
 799         struct uwb_dev *src_dev;
 800 
 801         /* Is there enough data to decode the event (and any IEs in
 802            its payload)? */
 803         if (evt->notif.size < sizeof(*drp_evt)) {
 804                 dev_err(dev, "DRP event: Not enough data to decode event "
 805                         "[%zu bytes left, %zu needed]\n",
 806                         evt->notif.size, sizeof(*drp_evt));
 807                 return 0;
 808         }
 809         bytes_left = evt->notif.size - sizeof(*drp_evt);
 810         drp_evt = container_of(evt->notif.rceb, struct uwb_rc_evt_drp, rceb);
 811         ielength = le16_to_cpu(drp_evt->ie_length);
 812         if (bytes_left != ielength) {
 813                 dev_err(dev, "DRP event: Not enough data in payload [%zu"
 814                         "bytes left, %zu declared in the event]\n",
 815                         bytes_left, ielength);
 816                 return 0;
 817         }
 818 
 819         memcpy(src_addr.data, &drp_evt->src_addr, sizeof(src_addr));
 820         src_dev = uwb_dev_get_by_devaddr(rc, &src_addr);
 821         if (!src_dev) {
 822                 /*
 823                  * A DRP notification from an unrecognized device.
 824                  *
 825                  * This is probably from a WUSB device that doesn't
 826                  * have an EUI-48 and therefore doesn't show up in the
 827                  * UWB device database.  It's safe to simply ignore
 828                  * these.
 829                  */
 830                 return 0;
 831         }
 832 
 833         mutex_lock(&rc->rsvs_mutex);
 834 
 835         /* We do not distinguish from the reason */
 836         uwb_drp_process_all(rc, drp_evt, ielength, src_dev);
 837 
 838         mutex_unlock(&rc->rsvs_mutex);
 839 
 840         uwb_dev_put(src_dev);
 841         return 0;
 842 }