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