drivers/uwb/wlp/wlp-lc.c

   1 /*
   2  * WiMedia Logical Link Control Protocol (WLP)
   3  *
   4  * Copyright (C) 2005-2006 Intel Corporation
   5  * Reinette Chatre <reinette.chatre@intel.com>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License version
   9  * 2 as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19  * 02110-1301, USA.
  20  *
  21  *
  22  * FIXME: docs
  23  */
  24
  25 #include <linux/wlp.h>
  26 #define D_LOCAL 6
  27 #include <linux/uwb/debug.h>
  28 #include "wlp-internal.h"
  29
  30
  31 static
  32 void wlp_neighbor_init(struct wlp_neighbor_e *neighbor)
  33 {
  34         INIT_LIST_HEAD(&neighbor->wssid);
  35 }
  36
  37 /**
  38  * Create area for device information storage
  39  *
  40  * wlp->mutex must be held
  41  */
  42 int __wlp_alloc_device_info(struct wlp *wlp)
  43 {
  44         struct device *dev = &wlp->rc->uwb_dev.dev;
  45         BUG_ON(wlp->dev_info != NULL);
  46         wlp->dev_info = kzalloc(sizeof(struct wlp_device_info), GFP_KERNEL);
  47         if (wlp->dev_info == NULL) {
  48                 dev_err(dev, "WLP: Unable to allocate memory for "
  49                         "device information.\n");
  50                 return -ENOMEM;
  51         }
  52         return 0;
  53 }
  54
  55
  56 /**
  57  * Fill in device information using function provided by driver
  58  *
  59  * wlp->mutex must be held
  60  */
  61 static
  62 void __wlp_fill_device_info(struct wlp *wlp)
  63 {
  64         struct device *dev = &wlp->rc->uwb_dev.dev;
  65
  66         BUG_ON(wlp->fill_device_info == NULL);
  67         d_printf(6, dev, "Retrieving device information "
  68                          "from device driver.\n");
  69         wlp->fill_device_info(wlp, wlp->dev_info);
  70 }
  71
  72 /**
  73  * Setup device information
  74  *
  75  * Allocate area for device information and populate it.
  76  *
  77  * wlp->mutex must be held
  78  */
  79 int __wlp_setup_device_info(struct wlp *wlp)
  80 {
  81         int result;
  82         struct device *dev = &wlp->rc->uwb_dev.dev;
  83
  84         result = __wlp_alloc_device_info(wlp);
  85         if (result < 0) {
  86                 dev_err(dev, "WLP: Unable to allocate area for "
  87                         "device information.\n");
  88                 return result;
  89         }
  90         __wlp_fill_device_info(wlp);
  91         return 0;
  92 }
  93
  94 /**
  95  * Remove information about neighbor stored temporarily
  96  *
  97  * Information learned during discovey should only be stored when the
  98  * device enrolls in the neighbor's WSS. We do need to store this
  99  * information temporarily in order to present it to the user.
 100  *
 101  * We are only interested in keeping neighbor WSS information if that
 102  * neighbor is accepting enrollment.
 103  *
 104  * should be called with wlp->nbmutex held
 105  */
 106 void wlp_remove_neighbor_tmp_info(struct wlp_neighbor_e *neighbor)
 107 {
 108         struct wlp_wssid_e *wssid_e, *next;
 109         u8 keep;
 110         if (!list_empty(&neighbor->wssid)) {
 111                 list_for_each_entry_safe(wssid_e, next, &neighbor->wssid,
 112                                          node) {
 113                         if (wssid_e->info != NULL) {
 114                                 keep = wssid_e->info->accept_enroll;
 115                                 kfree(wssid_e->info);
 116                                 wssid_e->info = NULL;
 117                                 if (!keep) {
 118                                         list_del(&wssid_e->node);
 119                                         kfree(wssid_e);
 120                                 }
 121                         }
 122                 }
 123         }
 124         if (neighbor->info != NULL) {
 125                 kfree(neighbor->info);
 126                 neighbor->info = NULL;
 127         }
 128 }
 129
 130 /**
 131  * Populate WLP neighborhood cache with neighbor information
 132  *
 133  * A new neighbor is found. If it is discoverable then we add it to the
 134  * neighborhood cache.
 135  *
 136  */
 137 static
 138 int wlp_add_neighbor(struct wlp *wlp, struct uwb_dev *dev)
 139 {
 140         int result = 0;
 141         int discoverable;
 142         struct wlp_neighbor_e *neighbor;
 143
 144         d_fnstart(6, &dev->dev, "uwb %p \n", dev);
 145         d_printf(6, &dev->dev, "Found neighbor device %02x:%02x \n",
 146                  dev->dev_addr.data[1], dev->dev_addr.data[0]);
 147         /**
 148          * FIXME:
 149          * Use contents of WLP IE found in beacon cache to determine if
 150          * neighbor is discoverable.
 151          * The device does not support WLP IE yet so this still needs to be
 152          * done. Until then we assume all devices are discoverable.
 153          */
 154         discoverable = 1; /* will be changed when FIXME disappears */
 155         if (discoverable) {
 156                 /* Add neighbor to cache for discovery */
 157                 neighbor = kzalloc(sizeof(*neighbor), GFP_KERNEL);
 158                 if (neighbor == NULL) {
 159                         dev_err(&dev->dev, "Unable to create memory for "
 160                                 "new neighbor. \n");
 161                         result = -ENOMEM;
 162                         goto error_no_mem;
 163                 }
 164                 wlp_neighbor_init(neighbor);
 165                 uwb_dev_get(dev);
 166                 neighbor->uwb_dev = dev;
 167                 list_add(&neighbor->node, &wlp->neighbors);
 168         }
 169 error_no_mem:
 170         d_fnend(6, &dev->dev, "uwb %p, result = %d \n", dev, result);
 171         return result;
 172 }
 173
 174 /**
 175  * Remove one neighbor from cache
 176  */
 177 static
 178 void __wlp_neighbor_release(struct wlp_neighbor_e *neighbor)
 179 {
 180         struct wlp_wssid_e *wssid_e, *next_wssid_e;
 181
 182         list_for_each_entry_safe(wssid_e, next_wssid_e,
 183                                  &neighbor->wssid, node) {
 184                 list_del(&wssid_e->node);
 185                 kfree(wssid_e);
 186         }
 187         uwb_dev_put(neighbor->uwb_dev);
 188         list_del(&neighbor->node);
 189         kfree(neighbor);
 190 }
 191
 192 /**
 193  * Clear entire neighborhood cache.
 194  */
 195 static
 196 void __wlp_neighbors_release(struct wlp *wlp)
 197 {
 198         struct wlp_neighbor_e *neighbor, *next;
 199         if (list_empty(&wlp->neighbors))
 200                 return;
 201         list_for_each_entry_safe(neighbor, next, &wlp->neighbors, node) {
 202                 __wlp_neighbor_release(neighbor);
 203         }
 204 }
 205
 206 static
 207 void wlp_neighbors_release(struct wlp *wlp)
 208 {
 209         mutex_lock(&wlp->nbmutex);
 210         __wlp_neighbors_release(wlp);
 211         mutex_unlock(&wlp->nbmutex);
 212 }
 213
 214
 215
 216 /**
 217  * Send D1 message to neighbor, receive D2 message
 218  *
 219  * @neighbor: neighbor to which D1 message will be sent
 220  * @wss:      if not NULL, it is an enrollment request for this WSS
 221  * @wssid:    if wss not NULL, this is the wssid of the WSS in which we
 222  *            want to enroll
 223  *
 224  * A D1/D2 exchange is done for one of two reasons: discovery or
 225  * enrollment. If done for discovery the D1 message is sent to the neighbor
 226  * and the contents of the D2 response is stored in a temporary cache.
 227  * If done for enrollment the @wss and @wssid are provided also. In this
 228  * case the D1 message is sent to the neighbor, the D2 response is parsed
 229  * for enrollment of the WSS with wssid.
 230  *
 231  * &wss->mutex is held
 232  */
 233 static
 234 int wlp_d1d2_exchange(struct wlp *wlp, struct wlp_neighbor_e *neighbor,
 235                       struct wlp_wss *wss, struct wlp_uuid *wssid)
 236 {
 237         int result;
 238         struct device *dev = &wlp->rc->uwb_dev.dev;
 239         DECLARE_COMPLETION_ONSTACK(completion);
 240         struct wlp_session session;
 241         struct sk_buff  *skb;
 242         struct wlp_frame_assoc *resp;
 243         struct uwb_dev_addr *dev_addr = &neighbor->uwb_dev->dev_addr;
 244
 245         mutex_lock(&wlp->mutex);
 246         if (!wlp_uuid_is_set(&wlp->uuid)) {
 247                 dev_err(dev, "WLP: UUID is not set. Set via sysfs to "
 248                         "proceed.\n");
 249                 result = -ENXIO;
 250                 goto out;
 251         }
 252         /* Send D1 association frame */
 253         result = wlp_send_assoc_frame(wlp, wss, dev_addr, WLP_ASSOC_D1);
 254         if (result < 0) {
 255                 dev_err(dev, "Unable to send D1 frame to neighbor "
 256                         "%02x:%02x (%d)\n", dev_addr->data[1],
 257                         dev_addr->data[0], result);
 258                 d_printf(6, dev, "Add placeholders into buffer next to "
 259                          "neighbor information we have (dev address).\n");
 260                 goto out;
 261         }
 262         /* Create session, wait for response */
 263         session.exp_message = WLP_ASSOC_D2;
 264         session.cb = wlp_session_cb;
 265         session.cb_priv = &completion;
 266         session.neighbor_addr = *dev_addr;
 267         BUG_ON(wlp->session != NULL);
 268         wlp->session = &session;
 269         /* Wait for D2/F0 frame */
 270         result = wait_for_completion_interruptible_timeout(&completion,
 271                                                    WLP_PER_MSG_TIMEOUT * HZ);
 272         if (result == 0) {
 273                 result = -ETIMEDOUT;
 274                 dev_err(dev, "Timeout while sending D1 to neighbor "
 275                              "%02x:%02x.\n", dev_addr->data[1],
 276                              dev_addr->data[0]);
 277                 goto error_session;
 278         }
 279         if (result < 0) {
 280                 dev_err(dev, "Unable to discover/enroll neighbor %02x:%02x.\n",
 281                         dev_addr->data[1], dev_addr->data[0]);
 282                 goto error_session;
 283         }
 284         /* Parse message in session->data: it will be either D2 or F0 */
 285         skb = session.data;
 286         resp = (void *) skb->data;
 287         d_printf(6, dev, "Received response to D1 frame. \n");
 288         d_dump(6, dev, skb->data, skb->len > 72 ? 72 : skb->len);
 289
 290         if (resp->type == WLP_ASSOC_F0) {
 291                 result = wlp_parse_f0(wlp, skb);
 292                 if (result < 0)
 293                         dev_err(dev, "WLP: Unable to parse F0 from neighbor "
 294                                 "%02x:%02x.\n", dev_addr->data[1],
 295                                 dev_addr->data[0]);
 296                 result = -EINVAL;
 297                 goto error_resp_parse;
 298         }
 299         if (wss == NULL) {
 300                 /* Discovery */
 301                 result = wlp_parse_d2_frame_to_cache(wlp, skb, neighbor);
 302                 if (result < 0) {
 303                         dev_err(dev, "WLP: Unable to parse D2 message from "
 304                                 "neighbor %02x:%02x for discovery.\n",
 305                                 dev_addr->data[1], dev_addr->data[0]);
 306                         goto error_resp_parse;
 307                 }
 308         } else {
 309                 /* Enrollment */
 310                 result = wlp_parse_d2_frame_to_enroll(wss, skb, neighbor,
 311                                                       wssid);
 312                 if (result < 0) {
 313                         dev_err(dev, "WLP: Unable to parse D2 message from "
 314                                 "neighbor %02x:%02x for enrollment.\n",
 315                                 dev_addr->data[1], dev_addr->data[0]);
 316                         goto error_resp_parse;
 317                 }
 318         }
 319 error_resp_parse:
 320         kfree_skb(skb);
 321 error_session:
 322         wlp->session = NULL;
 323 out:
 324         mutex_unlock(&wlp->mutex);
 325         return result;
 326 }
 327
 328 /**
 329  * Enroll into WSS of provided WSSID by using neighbor as registrar
 330  *
 331  * &wss->mutex is held
 332  */
 333 int wlp_enroll_neighbor(struct wlp *wlp, struct wlp_neighbor_e *neighbor,
 334                         struct wlp_wss *wss, struct wlp_uuid *wssid)
 335 {
 336         int result = 0;
 337         struct device *dev = &wlp->rc->uwb_dev.dev;
 338         char buf[WLP_WSS_UUID_STRSIZE];
 339         struct uwb_dev_addr *dev_addr = &neighbor->uwb_dev->dev_addr;
 340         wlp_wss_uuid_print(buf, sizeof(buf), wssid);
 341         d_fnstart(6, dev, "wlp %p, neighbor %p, wss %p, wssid %p (%s)\n",
 342                   wlp, neighbor, wss, wssid, buf);
 343         d_printf(6, dev, "Complete me.\n");
 344         result =  wlp_d1d2_exchange(wlp, neighbor, wss, wssid);
 345         if (result < 0) {
 346                 dev_err(dev, "WLP: D1/D2 message exchange for enrollment "
 347                         "failed. result = %d \n", result);
 348                 goto out;
 349         }
 350         if (wss->state != WLP_WSS_STATE_PART_ENROLLED) {
 351                 dev_err(dev, "WLP: Unable to enroll into WSS %s using "
 352                         "neighbor %02x:%02x. \n", buf,
 353                         dev_addr->data[1], dev_addr->data[0]);
 354                 result = -EINVAL;
 355                 goto out;
 356         }
 357         if (wss->secure_status == WLP_WSS_SECURE) {
 358                 dev_err(dev, "FIXME: need to complete secure enrollment.\n");
 359                 result = -EINVAL;
 360                 goto error;
 361         } else {
 362                 wss->state = WLP_WSS_STATE_ENROLLED;
 363                 d_printf(2, dev, "WLP: Success Enrollment into unsecure WSS "
 364                          "%s using neighbor %02x:%02x. \n", buf,
 365                          dev_addr->data[1], dev_addr->data[0]);
 366         }
 367
 368         d_fnend(6, dev, "wlp %p, neighbor %p, wss %p, wssid %p (%s)\n",
 369                   wlp, neighbor, wss, wssid, buf);
 370 out:
 371         return result;
 372 error:
 373         wlp_wss_reset(wss);
 374         return result;
 375 }
 376
 377 /**
 378  * Discover WSS information of neighbor's active WSS
 379  */
 380 static
 381 int wlp_discover_neighbor(struct wlp *wlp,
 382                           struct wlp_neighbor_e *neighbor)
 383 {
 384         return wlp_d1d2_exchange(wlp, neighbor, NULL, NULL);
 385 }
 386
 387
 388 /**
 389  * Each neighbor in the neighborhood cache is discoverable. Discover it.
 390  *
 391  * Discovery is done through sending of D1 association frame and parsing
 392  * the D2 association frame response. Only wssid from D2 will be included
 393  * in neighbor cache, rest is just displayed to user and forgotten.
 394  *
 395  * The discovery is not done in parallel. This is simple and enables us to
 396  * maintain only one association context.
 397  *
 398  * The discovery of one neighbor does not affect the other, but if the
 399  * discovery of a neighbor fails it is removed from the neighborhood cache.
 400  */
 401 static
 402 int wlp_discover_all_neighbors(struct wlp *wlp)
 403 {
 404         int result = 0;
 405         struct device *dev = &wlp->rc->uwb_dev.dev;
 406         struct wlp_neighbor_e *neighbor, *next;
 407
 408         list_for_each_entry_safe(neighbor, next, &wlp->neighbors, node) {
 409                 result = wlp_discover_neighbor(wlp, neighbor);
 410                 if (result < 0) {
 411                         dev_err(dev, "WLP: Unable to discover neighbor "
 412                                 "%02x:%02x, removing from neighborhood. \n",
 413                                 neighbor->uwb_dev->dev_addr.data[1],
 414                                 neighbor->uwb_dev->dev_addr.data[0]);
 415                         __wlp_neighbor_release(neighbor);
 416                 }
 417         }
 418         return result;
 419 }
 420
 421 static int wlp_add_neighbor_helper(struct device *dev, void *priv)
 422 {
 423         struct wlp *wlp = priv;
 424         struct uwb_dev *uwb_dev = to_uwb_dev(dev);
 425
 426         return wlp_add_neighbor(wlp, uwb_dev);
 427 }
 428
 429 /**
 430  * Discover WLP neighborhood
 431  *
 432  * Will send D1 association frame to all devices in beacon group that have
 433  * discoverable bit set in WLP IE. D2 frames will be received, information
 434  * displayed to user in @buf. Partial information (from D2 association
 435  * frame) will be cached to assist with future association
 436  * requests.
 437  *
 438  * The discovery of the WLP neighborhood is triggered by the user. This
 439  * should occur infrequently and we thus free current cache and re-allocate
 440  * memory if needed.
 441  *
 442  * If one neighbor fails during initial discovery (determining if it is a
 443  * neighbor or not), we fail all - note that interaction with neighbor has
 444  * not occured at this point so if a failure occurs we know something went wrong
 445  * locally. We thus undo everything.
 446  */
 447 ssize_t wlp_discover(struct wlp *wlp)
 448 {
 449         int result = 0;
 450         struct device *dev = &wlp->rc->uwb_dev.dev;
 451
 452         d_fnstart(6, dev, "wlp %p \n", wlp);
 453         mutex_lock(&wlp->nbmutex);
 454         /* Clear current neighborhood cache. */
 455         __wlp_neighbors_release(wlp);
 456         /* Determine which devices in neighborhood. Repopulate cache. */
 457         result = uwb_dev_for_each(wlp->rc, wlp_add_neighbor_helper, wlp);
 458         if (result < 0) {
 459                 /* May have partial neighbor information, release all. */
 460                 __wlp_neighbors_release(wlp);
 461                 goto error_dev_for_each;
 462         }
 463         /* Discover the properties of devices in neighborhood. */
 464         result = wlp_discover_all_neighbors(wlp);
 465         /* In case of failure we still print our partial results. */
 466         if (result < 0) {
 467                 dev_err(dev, "Unable to fully discover neighborhood. \n");
 468                 result = 0;
 469         }
 470 error_dev_for_each:
 471         mutex_unlock(&wlp->nbmutex);
 472         d_fnend(6, dev, "wlp %p \n", wlp);
 473         return result;
 474 }
 475
 476 /**
 477  * Handle events from UWB stack
 478  *
 479  * We handle events conservatively. If a neighbor goes off the air we
 480  * remove it from the neighborhood. If an association process is in
 481  * progress this function will block waiting for the nbmutex to become
 482  * free. The association process will thus be allowed to complete before it
 483  * is removed.
 484  */
 485 static
 486 void wlp_uwb_notifs_cb(void *_wlp, struct uwb_dev *uwb_dev,
 487                        enum uwb_notifs event)
 488 {
 489         struct wlp *wlp = _wlp;
 490         struct device *dev = &wlp->rc->uwb_dev.dev;
 491         struct wlp_neighbor_e *neighbor, *next;
 492         int result;
 493         switch (event) {
 494         case UWB_NOTIF_ONAIR:
 495                 d_printf(6, dev, "UWB device %02x:%02x is onair\n",
 496                                 uwb_dev->dev_addr.data[1],
 497                                 uwb_dev->dev_addr.data[0]);
 498                 result = wlp_eda_create_node(&wlp->eda,
 499                                              uwb_dev->mac_addr.data,
 500                                              &uwb_dev->dev_addr);
 501                 if (result < 0)
 502                         dev_err(dev, "WLP: Unable to add new neighbor "
 503                                 "%02x:%02x to EDA cache.\n",
 504                                 uwb_dev->dev_addr.data[1],
 505                                 uwb_dev->dev_addr.data[0]);
 506                 break;
 507         case UWB_NOTIF_OFFAIR:
 508                 d_printf(6, dev, "UWB device %02x:%02x is offair\n",
 509                                 uwb_dev->dev_addr.data[1],
 510                                 uwb_dev->dev_addr.data[0]);
 511                 wlp_eda_rm_node(&wlp->eda, &uwb_dev->dev_addr);
 512                 mutex_lock(&wlp->nbmutex);
 513                 list_for_each_entry_safe(neighbor, next, &wlp->neighbors,
 514                                          node) {
 515                         if (neighbor->uwb_dev == uwb_dev) {
 516                                 d_printf(6, dev, "Removing device from "
 517                                          "neighborhood.\n");
 518                                 __wlp_neighbor_release(neighbor);
 519                         }
 520                 }
 521                 mutex_unlock(&wlp->nbmutex);
 522                 break;
 523         default:
 524                 dev_err(dev, "don't know how to handle event %d from uwb\n",
 525                                 event);
 526         }
 527 }
 528
 529 int wlp_setup(struct wlp *wlp, struct uwb_rc *rc)
 530 {
 531         struct device *dev = &rc->uwb_dev.dev;
 532         int result;
 533
 534         d_fnstart(6, dev, "wlp %p\n", wlp);
 535         BUG_ON(wlp->fill_device_info == NULL);
 536         BUG_ON(wlp->xmit_frame == NULL);
 537         BUG_ON(wlp->stop_queue == NULL);
 538         BUG_ON(wlp->start_queue == NULL);
 539         wlp->rc = rc;
 540         wlp_eda_init(&wlp->eda);/* Set up address cache */
 541         wlp->uwb_notifs_handler.cb = wlp_uwb_notifs_cb;
 542         wlp->uwb_notifs_handler.data = wlp;
 543         uwb_notifs_register(rc, &wlp->uwb_notifs_handler);
 544
 545         uwb_pal_init(&wlp->pal);
 546         result = uwb_pal_register(rc, &wlp->pal);
 547         if (result < 0)
 548                 uwb_notifs_deregister(wlp->rc, &wlp->uwb_notifs_handler);
 549
 550         d_fnend(6, dev, "wlp %p, result = %d\n", wlp, result);
 551         return result;
 552 }
 553 EXPORT_SYMBOL_GPL(wlp_setup);
 554
 555 void wlp_remove(struct wlp *wlp)
 556 {
 557         struct device *dev = &wlp->rc->uwb_dev.dev;
 558         d_fnstart(6, dev, "wlp %p\n", wlp);
 559         wlp_neighbors_release(wlp);
 560         uwb_pal_unregister(wlp->rc, &wlp->pal);
 561         uwb_notifs_deregister(wlp->rc, &wlp->uwb_notifs_handler);
 562         wlp_eda_release(&wlp->eda);
 563         mutex_lock(&wlp->mutex);
 564         if (wlp->dev_info != NULL)
 565                 kfree(wlp->dev_info);
 566         mutex_unlock(&wlp->mutex);
 567         wlp->rc = NULL;
 568         /* We have to use NULL here because this function can be called
 569          * when the device disappeared. */
 570         d_fnend(6, NULL, "wlp %p\n", wlp);
 571 }
 572 EXPORT_SYMBOL_GPL(wlp_remove);
 573
 574 /**
 575  * wlp_reset_all - reset the WLP hardware
 576  * @wlp: the WLP device to reset.
 577  *
 578  * This schedules a full hardware reset of the WLP device.  The radio
 579  * controller and any other PALs will also be reset.
 580  */
 581 void wlp_reset_all(struct wlp *wlp)
 582 {
 583         uwb_rc_reset_all(wlp->rc);
 584 }
 585 EXPORT_SYMBOL_GPL(wlp_reset_all);