linux/drivers/uwb/hwa-rc.c
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   1/*
   2 * WUSB Host Wire Adapter: Radio Control Interface (WUSB[8.6])
   3 * Radio Control command/event transport
   4 *
   5 * Copyright (C) 2005-2006 Intel Corporation
   6 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
   7 *
   8 * This program is free software; you can redistribute it and/or
   9 * modify it under the terms of the GNU General Public License version
  10 * 2 as published by the Free Software Foundation.
  11 *
  12 * This program is distributed in the hope that it will be useful,
  13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 * GNU General Public License for more details.
  16 *
  17 * You should have received a copy of the GNU General Public License
  18 * along with this program; if not, write to the Free Software
  19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  20 * 02110-1301, USA.
  21 *
  22 *
  23 * Initialize the Radio Control interface Driver.
  24 *
  25 * For each device probed, creates an 'struct hwarc' which contains
  26 * just the representation of the UWB Radio Controller, and the logic
  27 * for reading notifications and passing them to the UWB Core.
  28 *
  29 * So we initialize all of those, register the UWB Radio Controller
  30 * and setup the notification/event handle to pipe the notifications
  31 * to the UWB management Daemon.
  32 *
  33 * Command and event filtering.
  34 *
  35 * This is the driver for the Radio Control Interface described in WUSB
  36 * 1.0. The core UWB module assumes that all drivers are compliant to the
  37 * WHCI 0.95 specification. We thus create a filter that parses all
  38 * incoming messages from the (WUSB 1.0) device and manipulate them to
  39 * conform to the WHCI 0.95 specification. Similarly, outgoing messages
  40 * are parsed and manipulated to conform to the WUSB 1.0 compliant messages
  41 * that the device expects. Only a few messages are affected:
  42 * Affected events:
  43 *    UWB_RC_EVT_BEACON
  44 *    UWB_RC_EVT_BP_SLOT_CHANGE
  45 *    UWB_RC_EVT_DRP_AVAIL
  46 *    UWB_RC_EVT_DRP
  47 * Affected commands:
  48 *    UWB_RC_CMD_SCAN
  49 *    UWB_RC_CMD_SET_DRP_IE
  50 *
  51 *
  52 *
  53 */
  54#include <linux/version.h>
  55#include <linux/init.h>
  56#include <linux/module.h>
  57#include <linux/usb.h>
  58#include <linux/usb/wusb.h>
  59#include <linux/usb/wusb-wa.h>
  60#include <linux/uwb.h>
  61#include "uwb-internal.h"
  62#define D_LOCAL 1
  63#include <linux/uwb/debug.h>
  64
  65/* The device uses commands and events from the WHCI specification, although
  66 * reporting itself as WUSB compliant. */
  67#define WUSB_QUIRK_WHCI_CMD_EVT         0x01
  68
  69/**
  70 * Descriptor for an instance of the UWB Radio Control Driver that
  71 * attaches to the RCI interface of the Host Wired Adapter.
  72 *
  73 * Unless there is a lock specific to the 'data members', all access
  74 * is protected by uwb_rc->mutex.
  75 *
  76 * The NEEP (Notification/Event EndPoint) URB (@neep_urb) writes to
  77 * @rd_buffer. Note there is no locking because it is perfectly (heh!)
  78 * serialized--probe() submits an URB, callback is called, processes
  79 * the data (synchronously), submits another URB, and so on. There is
  80 * no concurrent access to the buffer.
  81 */
  82struct hwarc {
  83        struct usb_device *usb_dev;
  84        struct usb_interface *usb_iface;
  85        struct uwb_rc *uwb_rc;          /* UWB host controller */
  86        struct urb *neep_urb;           /* Notification endpoint handling */
  87        struct edc neep_edc;
  88        void *rd_buffer;                /* NEEP read buffer */
  89};
  90
  91
  92/* Beacon received notification (WUSB 1.0 [8.6.3.2]) */
  93struct uwb_rc_evt_beacon_WUSB_0100 {
  94        struct uwb_rceb rceb;
  95        u8      bChannelNumber;
  96        __le16  wBPSTOffset;
  97        u8      bLQI;
  98        u8      bRSSI;
  99        __le16  wBeaconInfoLength;
 100        u8      BeaconInfo[];
 101} __attribute__((packed));
 102
 103/**
 104 * Filter WUSB 1.0 BEACON RCV notification to be WHCI 0.95
 105 *
 106 * @header: the incoming event
 107 * @buf_size: size of buffer containing incoming event
 108 * @new_size: size of event after filtering completed
 109 *
 110 * The WHCI 0.95 spec has a "Beacon Type" field. This value is unknown at
 111 * the time we receive the beacon from WUSB so we just set it to
 112 * UWB_RC_BEACON_TYPE_NEIGHBOR as a default.
 113 * The solution below allocates memory upon receipt of every beacon from a
 114 * WUSB device. This will deteriorate performance. What is the right way to
 115 * do this?
 116 */
 117static
 118int hwarc_filter_evt_beacon_WUSB_0100(struct uwb_rc *rc,
 119                                      struct uwb_rceb **header,
 120                                      const size_t buf_size,
 121                                      size_t *new_size)
 122{
 123        struct uwb_rc_evt_beacon_WUSB_0100 *be;
 124        struct uwb_rc_evt_beacon *newbe;
 125        size_t bytes_left, ielength;
 126        struct device *dev = &rc->uwb_dev.dev;
 127
 128        be = container_of(*header, struct uwb_rc_evt_beacon_WUSB_0100, rceb);
 129        bytes_left = buf_size;
 130        if (bytes_left < sizeof(*be)) {
 131                dev_err(dev, "Beacon Received Notification: Not enough data "
 132                        "to decode for filtering (%zu vs %zu bytes needed)\n",
 133                        bytes_left, sizeof(*be));
 134                return -EINVAL;
 135        }
 136        bytes_left -= sizeof(*be);
 137        ielength = le16_to_cpu(be->wBeaconInfoLength);
 138        if (bytes_left < ielength) {
 139                dev_err(dev, "Beacon Received Notification: Not enough data "
 140                        "to decode IEs (%zu vs %zu bytes needed)\n",
 141                        bytes_left, ielength);
 142                return -EINVAL;
 143        }
 144        newbe = kzalloc(sizeof(*newbe) + ielength, GFP_ATOMIC);
 145        if (newbe == NULL)
 146                return -ENOMEM;
 147        newbe->rceb = be->rceb;
 148        newbe->bChannelNumber = be->bChannelNumber;
 149        newbe->bBeaconType = UWB_RC_BEACON_TYPE_NEIGHBOR;
 150        newbe->wBPSTOffset = be->wBPSTOffset;
 151        newbe->bLQI = be->bLQI;
 152        newbe->bRSSI = be->bRSSI;
 153        newbe->wBeaconInfoLength = be->wBeaconInfoLength;
 154        memcpy(newbe->BeaconInfo, be->BeaconInfo, ielength);
 155        *header = &newbe->rceb;
 156        *new_size = sizeof(*newbe) + ielength;
 157        return 1;  /* calling function will free memory */
 158}
 159
 160
 161/* DRP Availability change notification (WUSB 1.0 [8.6.3.8]) */
 162struct uwb_rc_evt_drp_avail_WUSB_0100 {
 163        struct uwb_rceb rceb;
 164        __le16 wIELength;
 165        u8 IEData[];
 166} __attribute__((packed));
 167
 168/**
 169 * Filter WUSB 1.0 DRP AVAILABILITY CHANGE notification to be WHCI 0.95
 170 *
 171 * @header: the incoming event
 172 * @buf_size: size of buffer containing incoming event
 173 * @new_size: size of event after filtering completed
 174 */
 175static
 176int hwarc_filter_evt_drp_avail_WUSB_0100(struct uwb_rc *rc,
 177                                         struct uwb_rceb **header,
 178                                         const size_t buf_size,
 179                                         size_t *new_size)
 180{
 181        struct uwb_rc_evt_drp_avail_WUSB_0100 *da;
 182        struct uwb_rc_evt_drp_avail *newda;
 183        struct uwb_ie_hdr *ie_hdr;
 184        size_t bytes_left, ielength;
 185        struct device *dev = &rc->uwb_dev.dev;
 186
 187
 188        da = container_of(*header, struct uwb_rc_evt_drp_avail_WUSB_0100, rceb);
 189        bytes_left = buf_size;
 190        if (bytes_left < sizeof(*da)) {
 191                dev_err(dev, "Not enough data to decode DRP Avail "
 192                        "Notification for filtering. Expected %zu, "
 193                        "received %zu.\n", (size_t)sizeof(*da), bytes_left);
 194                return -EINVAL;
 195        }
 196        bytes_left -= sizeof(*da);
 197        ielength = le16_to_cpu(da->wIELength);
 198        if (bytes_left < ielength) {
 199                dev_err(dev, "DRP Avail Notification filter: IE length "
 200                        "[%zu bytes] does not match actual length "
 201                        "[%zu bytes].\n", ielength, bytes_left);
 202                return -EINVAL;
 203        }
 204        if (ielength < sizeof(*ie_hdr)) {
 205                dev_err(dev, "DRP Avail Notification filter: Not enough "
 206                        "data to decode IE [%zu bytes, %zu needed]\n",
 207                        ielength, sizeof(*ie_hdr));
 208                return -EINVAL;
 209        }
 210        ie_hdr = (void *) da->IEData;
 211        if (ie_hdr->length > 32) {
 212                dev_err(dev, "DRP Availability Change event has unexpected "
 213                        "length for filtering. Expected < 32 bytes, "
 214                        "got %zu bytes.\n", (size_t)ie_hdr->length);
 215                return -EINVAL;
 216        }
 217        newda = kzalloc(sizeof(*newda), GFP_ATOMIC);
 218        if (newda == NULL)
 219                return -ENOMEM;
 220        newda->rceb = da->rceb;
 221        memcpy(newda->bmp, (u8 *) ie_hdr + sizeof(*ie_hdr), ie_hdr->length);
 222        *header = &newda->rceb;
 223        *new_size = sizeof(*newda);
 224        return 1; /* calling function will free memory */
 225}
 226
 227
 228/* DRP notification (WUSB 1.0 [8.6.3.9]) */
 229struct uwb_rc_evt_drp_WUSB_0100 {
 230        struct uwb_rceb rceb;
 231        struct uwb_dev_addr wSrcAddr;
 232        u8 bExplicit;
 233        __le16 wIELength;
 234        u8 IEData[];
 235} __attribute__((packed));
 236
 237/**
 238 * Filter WUSB 1.0 DRP Notification to be WHCI 0.95
 239 *
 240 * @header: the incoming event
 241 * @buf_size: size of buffer containing incoming event
 242 * @new_size: size of event after filtering completed
 243 *
 244 * It is hard to manage DRP reservations without having a Reason code.
 245 * Unfortunately there is none in the WUSB spec. We just set the default to
 246 * DRP IE RECEIVED.
 247 * We do not currently use the bBeaconSlotNumber value, so we set this to
 248 * zero for now.
 249 */
 250static
 251int hwarc_filter_evt_drp_WUSB_0100(struct uwb_rc *rc,
 252                                   struct uwb_rceb **header,
 253                                   const size_t buf_size,
 254                                   size_t *new_size)
 255{
 256        struct uwb_rc_evt_drp_WUSB_0100 *drpev;
 257        struct uwb_rc_evt_drp *newdrpev;
 258        size_t bytes_left, ielength;
 259        struct device *dev = &rc->uwb_dev.dev;
 260
 261        drpev = container_of(*header, struct uwb_rc_evt_drp_WUSB_0100, rceb);
 262        bytes_left = buf_size;
 263        if (bytes_left < sizeof(*drpev)) {
 264                dev_err(dev, "Not enough data to decode DRP Notification "
 265                        "for filtering. Expected %zu, received %zu.\n",
 266                        (size_t)sizeof(*drpev), bytes_left);
 267                return -EINVAL;
 268        }
 269        ielength = le16_to_cpu(drpev->wIELength);
 270        bytes_left -= sizeof(*drpev);
 271        if (bytes_left < ielength) {
 272                dev_err(dev, "DRP Notification filter: header length [%zu "
 273                        "bytes] does not match actual length [%zu "
 274                        "bytes].\n", ielength, bytes_left);
 275                return -EINVAL;
 276        }
 277        newdrpev = kzalloc(sizeof(*newdrpev) + ielength, GFP_ATOMIC);
 278        if (newdrpev == NULL)
 279                return -ENOMEM;
 280        newdrpev->rceb = drpev->rceb;
 281        newdrpev->src_addr = drpev->wSrcAddr;
 282        newdrpev->reason = UWB_DRP_NOTIF_DRP_IE_RCVD;
 283        newdrpev->beacon_slot_number = 0;
 284        newdrpev->ie_length = drpev->wIELength;
 285        memcpy(newdrpev->ie_data, drpev->IEData, ielength);
 286        *header = &newdrpev->rceb;
 287        *new_size = sizeof(*newdrpev) + ielength;
 288        return 1; /* calling function will free memory */
 289}
 290
 291
 292/* Scan Command (WUSB 1.0 [8.6.2.5]) */
 293struct uwb_rc_cmd_scan_WUSB_0100 {
 294        struct uwb_rccb rccb;
 295        u8 bChannelNumber;
 296        u8 bScanState;
 297} __attribute__((packed));
 298
 299/**
 300 * Filter WHCI 0.95 SCAN command to be WUSB 1.0 SCAN command
 301 *
 302 * @header:   command sent to device (compliant to WHCI 0.95)
 303 * @size:     size of command sent to device
 304 *
 305 * We only reduce the size by two bytes because the WUSB 1.0 scan command
 306 * does not have the last field (wStarttime). Also, make sure we don't send
 307 * the device an unexpected scan type.
 308 */
 309static
 310int hwarc_filter_cmd_scan_WUSB_0100(struct uwb_rc *rc,
 311                                    struct uwb_rccb **header,
 312                                    size_t *size)
 313{
 314        struct uwb_rc_cmd_scan *sc;
 315
 316        sc = container_of(*header, struct uwb_rc_cmd_scan, rccb);
 317
 318        if (sc->bScanState == UWB_SCAN_ONLY_STARTTIME)
 319                sc->bScanState = UWB_SCAN_ONLY;
 320        /* Don't send the last two bytes. */
 321        *size -= 2;
 322        return 0;
 323}
 324
 325
 326/* SET DRP IE command (WUSB 1.0 [8.6.2.7]) */
 327struct uwb_rc_cmd_set_drp_ie_WUSB_0100 {
 328        struct uwb_rccb rccb;
 329        u8 bExplicit;
 330        __le16 wIELength;
 331        struct uwb_ie_drp IEData[];
 332} __attribute__((packed));
 333
 334/**
 335 * Filter WHCI 0.95 SET DRP IE command to be WUSB 1.0 SET DRP IE command
 336 *
 337 * @header:   command sent to device (compliant to WHCI 0.95)
 338 * @size:     size of command sent to device
 339 *
 340 * WUSB has an extra bExplicit field - we assume always explicit
 341 * negotiation so this field is set. The command expected by the device is
 342 * thus larger than the one prepared by the driver so we need to
 343 * reallocate memory to accommodate this.
 344 * We trust the driver to send us the correct data so no checking is done
 345 * on incoming data - evn though it is variable length.
 346 */
 347static
 348int hwarc_filter_cmd_set_drp_ie_WUSB_0100(struct uwb_rc *rc,
 349                                          struct uwb_rccb **header,
 350                                          size_t *size)
 351{
 352        struct uwb_rc_cmd_set_drp_ie *orgcmd;
 353        struct uwb_rc_cmd_set_drp_ie_WUSB_0100 *cmd;
 354        size_t ielength;
 355
 356        orgcmd = container_of(*header, struct uwb_rc_cmd_set_drp_ie, rccb);
 357        ielength = le16_to_cpu(orgcmd->wIELength);
 358        cmd = kzalloc(sizeof(*cmd) + ielength, GFP_KERNEL);
 359        if (cmd == NULL)
 360                return -ENOMEM;
 361        cmd->rccb = orgcmd->rccb;
 362        cmd->bExplicit = 0;
 363        cmd->wIELength = orgcmd->wIELength;
 364        memcpy(cmd->IEData, orgcmd->IEData, ielength);
 365        *header = &cmd->rccb;
 366        *size = sizeof(*cmd) + ielength;
 367        return 1; /* calling function will free memory */
 368}
 369
 370
 371/**
 372 * Filter data from WHCI driver to WUSB device
 373 *
 374 * @header: WHCI 0.95 compliant command from driver
 375 * @size:   length of command
 376 *
 377 * The routine managing commands to the device (uwb_rc_cmd()) will call the
 378 * filtering function pointer (if it exists) before it passes any data to
 379 * the device. At this time the command has been formatted according to
 380 * WHCI 0.95 and is ready to be sent to the device.
 381 *
 382 * The filter function will be provided with the current command and its
 383 * length. The function will manipulate the command if necessary and
 384 * potentially reallocate memory for a command that needed more memory that
 385 * the given command. If new memory was created the function will return 1
 386 * to indicate to the calling function that the memory need to be freed
 387 * when not needed any more. The size will contain the new length of the
 388 * command.
 389 * If memory has not been allocated we rely on the original mechanisms to
 390 * free the memory of the command - even when we reduce the value of size.
 391 */
 392static
 393int hwarc_filter_cmd_WUSB_0100(struct uwb_rc *rc, struct uwb_rccb **header,
 394                               size_t *size)
 395{
 396        int result;
 397        struct uwb_rccb *rccb = *header;
 398        int cmd = le16_to_cpu(rccb->wCommand);
 399        switch (cmd) {
 400        case UWB_RC_CMD_SCAN:
 401                result = hwarc_filter_cmd_scan_WUSB_0100(rc, header, size);
 402                break;
 403        case UWB_RC_CMD_SET_DRP_IE:
 404                result = hwarc_filter_cmd_set_drp_ie_WUSB_0100(rc, header, size);
 405                break;
 406        default:
 407                result = -ENOANO;
 408                break;
 409        }
 410        return result;
 411}
 412
 413
 414/**
 415 * Filter data from WHCI driver to WUSB device
 416 *
 417 * @header: WHCI 0.95 compliant command from driver
 418 * @size:   length of command
 419 *
 420 * Filter commands based on which protocol the device supports. The WUSB
 421 * errata should be the same as WHCI 0.95 so we do not filter that here -
 422 * only WUSB 1.0.
 423 */
 424static
 425int hwarc_filter_cmd(struct uwb_rc *rc, struct uwb_rccb **header,
 426                     size_t *size)
 427{
 428        int result = -ENOANO;
 429        if (rc->version == 0x0100)
 430                result = hwarc_filter_cmd_WUSB_0100(rc, header, size);
 431        return result;
 432}
 433
 434
 435/**
 436 * Compute return value as sum of incoming value and value at given offset
 437 *
 438 * @rceb:      event for which we compute the size, it contains a variable
 439 *             length field.
 440 * @core_size: size of the "non variable" part of the event
 441 * @offset:    place in event where the length of the variable part is stored
 442 * @buf_size: total length of buffer in which event arrived - we need to make
 443 *             sure we read the offset in memory that is still part of the event
 444 */
 445static
 446ssize_t hwarc_get_event_size(struct uwb_rc *rc, const struct uwb_rceb *rceb,
 447                             size_t core_size, size_t offset,
 448                             const size_t buf_size)
 449{
 450        ssize_t size = -ENOSPC;
 451        const void *ptr = rceb;
 452        size_t type_size = sizeof(__le16);
 453        struct device *dev = &rc->uwb_dev.dev;
 454
 455        if (offset + type_size >= buf_size) {
 456                dev_err(dev, "Not enough data to read extra size of event "
 457                        "0x%02x/%04x/%02x, only got %zu bytes.\n",
 458                        rceb->bEventType, le16_to_cpu(rceb->wEvent),
 459                        rceb->bEventContext, buf_size);
 460                goto out;
 461        }
 462        ptr += offset;
 463        size = core_size + le16_to_cpu(*(__le16 *)ptr);
 464out:
 465        return size;
 466}
 467
 468
 469/* Beacon slot change notification (WUSB 1.0 [8.6.3.5]) */
 470struct uwb_rc_evt_bp_slot_change_WUSB_0100 {
 471        struct uwb_rceb rceb;
 472        u8 bSlotNumber;
 473} __attribute__((packed));
 474
 475
 476/**
 477 * Filter data from WUSB device to WHCI driver
 478 *
 479 * @header:      incoming event
 480 * @buf_size:    size of buffer in which event arrived
 481 * @_event_size: actual size of event in the buffer
 482 * @new_size:    size of event after filtered
 483 *
 484 * We don't know how the buffer is constructed - there may be more than one
 485 * event in it so buffer length does not determine event length. We first
 486 * determine the expected size of the incoming event. This value is passed
 487 * back only if the actual filtering succeeded (so we know the computed
 488 * expected size is correct). This value will be zero if
 489 * the event did not need any filtering.
 490 *
 491 * WHCI interprets the BP Slot Change event's data differently than
 492 * WUSB. The event sizes are exactly the same. The data field
 493 * indicates the new beacon slot in which a RC is transmitting its
 494 * beacon. The maximum value of this is 96 (wMacBPLength ECMA-368
 495 * 17.16 (Table 117)). We thus know that the WUSB value will not set
 496 * the bit bNoSlot, so we don't really do anything (placeholder).
 497 */
 498static
 499int hwarc_filter_event_WUSB_0100(struct uwb_rc *rc, struct uwb_rceb **header,
 500                                 const size_t buf_size, size_t *_real_size,
 501                                 size_t *_new_size)
 502{
 503        int result = -ENOANO;
 504        struct uwb_rceb *rceb = *header;
 505        int event = le16_to_cpu(rceb->wEvent);
 506        size_t event_size;
 507        size_t core_size, offset;
 508
 509        if (rceb->bEventType != UWB_RC_CET_GENERAL)
 510                goto out;
 511        switch (event) {
 512        case UWB_RC_EVT_BEACON:
 513                core_size = sizeof(struct uwb_rc_evt_beacon_WUSB_0100);
 514                offset = offsetof(struct uwb_rc_evt_beacon_WUSB_0100,
 515                                  wBeaconInfoLength);
 516                event_size = hwarc_get_event_size(rc, rceb, core_size,
 517                                                  offset, buf_size);
 518                if (event_size < 0)
 519                        goto out;
 520                *_real_size = event_size;
 521                result = hwarc_filter_evt_beacon_WUSB_0100(rc, header,
 522                                                           buf_size, _new_size);
 523                break;
 524        case UWB_RC_EVT_BP_SLOT_CHANGE:
 525                *_new_size = *_real_size =
 526                        sizeof(struct uwb_rc_evt_bp_slot_change_WUSB_0100);
 527                result = 0;
 528                break;
 529
 530        case UWB_RC_EVT_DRP_AVAIL:
 531                core_size = sizeof(struct uwb_rc_evt_drp_avail_WUSB_0100);
 532                offset = offsetof(struct uwb_rc_evt_drp_avail_WUSB_0100,
 533                                  wIELength);
 534                event_size = hwarc_get_event_size(rc, rceb, core_size,
 535                                                  offset, buf_size);
 536                if (event_size < 0)
 537                        goto out;
 538                *_real_size = event_size;
 539                result = hwarc_filter_evt_drp_avail_WUSB_0100(
 540                        rc, header, buf_size, _new_size);
 541                break;
 542
 543        case UWB_RC_EVT_DRP:
 544                core_size = sizeof(struct uwb_rc_evt_drp_WUSB_0100);
 545                offset = offsetof(struct uwb_rc_evt_drp_WUSB_0100, wIELength);
 546                event_size = hwarc_get_event_size(rc, rceb, core_size,
 547                                                  offset, buf_size);
 548                if (event_size < 0)
 549                        goto out;
 550                *_real_size = event_size;
 551                result = hwarc_filter_evt_drp_WUSB_0100(rc, header,
 552                                                        buf_size, _new_size);
 553                break;
 554
 555        default:
 556                break;
 557        }
 558out:
 559        return result;
 560}
 561
 562/**
 563 * Filter data from WUSB device to WHCI driver
 564 *
 565 * @header:      incoming event
 566 * @buf_size:    size of buffer in which event arrived
 567 * @_event_size: actual size of event in the buffer
 568 * @_new_size:   size of event after filtered
 569 *
 570 * Filter events based on which protocol the device supports. The WUSB
 571 * errata should be the same as WHCI 0.95 so we do not filter that here -
 572 * only WUSB 1.0.
 573 *
 574 * If we don't handle it, we return -ENOANO (why the weird error code?
 575 * well, so if I get it, I can pinpoint in the code that raised
 576 * it...after all, not too many places use the higher error codes).
 577 */
 578static
 579int hwarc_filter_event(struct uwb_rc *rc, struct uwb_rceb **header,
 580                       const size_t buf_size, size_t *_real_size,
 581                       size_t *_new_size)
 582{
 583        int result = -ENOANO;
 584        if (rc->version == 0x0100)
 585                result =  hwarc_filter_event_WUSB_0100(
 586                        rc, header, buf_size, _real_size, _new_size);
 587        return result;
 588}
 589
 590
 591/**
 592 * Execute an UWB RC command on HWA
 593 *
 594 * @rc:       Instance of a Radio Controller that is a HWA
 595 * @cmd:      Buffer containing the RCCB and payload to execute
 596 * @cmd_size: Size of the command buffer.
 597 *
 598 * NOTE: rc's mutex has to be locked
 599 */
 600static
 601int hwarc_cmd(struct uwb_rc *uwb_rc, const struct uwb_rccb *cmd, size_t cmd_size)
 602{
 603        struct hwarc *hwarc = uwb_rc->priv;
 604        return usb_control_msg(
 605                hwarc->usb_dev, usb_sndctrlpipe(hwarc->usb_dev, 0),
 606                WA_EXEC_RC_CMD, USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 607                0, hwarc->usb_iface->cur_altsetting->desc.bInterfaceNumber,
 608                (void *) cmd, cmd_size, 100 /* FIXME: this is totally arbitrary */);
 609}
 610
 611static
 612int hwarc_reset(struct uwb_rc *uwb_rc)
 613{
 614        struct hwarc *hwarc = uwb_rc->priv;
 615        return usb_reset_device(hwarc->usb_dev);
 616}
 617
 618/**
 619 * Callback for the notification and event endpoint
 620 *
 621 * Check's that everything is fine and then passes the read data to
 622 * the notification/event handling mechanism (neh).
 623 */
 624static
 625void hwarc_neep_cb(struct urb *urb)
 626{
 627        struct hwarc *hwarc = urb->context;
 628        struct usb_interface *usb_iface = hwarc->usb_iface;
 629        struct device *dev = &usb_iface->dev;
 630        int result;
 631
 632        switch (result = urb->status) {
 633        case 0:
 634                d_printf(3, dev, "NEEP: receive stat %d, %zu bytes\n",
 635                         urb->status, (size_t)urb->actual_length);
 636                uwb_rc_neh_grok(hwarc->uwb_rc, urb->transfer_buffer,
 637                                urb->actual_length);
 638                break;
 639        case -ECONNRESET:       /* Not an error, but a controlled situation; */
 640        case -ENOENT:           /* (we killed the URB)...so, no broadcast */
 641                d_printf(2, dev, "NEEP: URB reset/noent %d\n", urb->status);
 642                goto out;
 643        case -ESHUTDOWN:        /* going away! */
 644                d_printf(2, dev, "NEEP: URB down %d\n", urb->status);
 645                goto out;
 646        default:                /* On general errors, retry unless it gets ugly */
 647                if (edc_inc(&hwarc->neep_edc, EDC_MAX_ERRORS,
 648                            EDC_ERROR_TIMEFRAME))
 649                        goto error_exceeded;
 650                dev_err(dev, "NEEP: URB error %d\n", urb->status);
 651        }
 652        result = usb_submit_urb(urb, GFP_ATOMIC);
 653        d_printf(3, dev, "NEEP: submit %d\n", result);
 654        if (result < 0) {
 655                dev_err(dev, "NEEP: Can't resubmit URB (%d) resetting device\n",
 656                        result);
 657                goto error;
 658        }
 659out:
 660        return;
 661
 662error_exceeded:
 663        dev_err(dev, "NEEP: URB max acceptable errors "
 664                "exceeded, resetting device\n");
 665error:
 666        uwb_rc_neh_error(hwarc->uwb_rc, result);
 667        uwb_rc_reset_all(hwarc->uwb_rc);
 668        return;
 669}
 670
 671static void hwarc_init(struct hwarc *hwarc)
 672{
 673        edc_init(&hwarc->neep_edc);
 674}
 675
 676/**
 677 * Initialize the notification/event endpoint stuff
 678 *
 679 * Note this is effectively a parallel thread; it knows that
 680 * hwarc->uwb_rc always exists because the existence of a 'hwarc'
 681 * means that there is a reverence on the hwarc->uwb_rc (see
 682 * _probe()), and thus _neep_cb() can execute safely.
 683 */
 684static int hwarc_neep_init(struct uwb_rc *rc)
 685{
 686        struct hwarc *hwarc = rc->priv;
 687        struct usb_interface *iface = hwarc->usb_iface;
 688        struct usb_device *usb_dev = interface_to_usbdev(iface);
 689        struct device *dev = &iface->dev;
 690        int result;
 691        struct usb_endpoint_descriptor *epd;
 692
 693        epd = &iface->cur_altsetting->endpoint[0].desc;
 694        hwarc->rd_buffer = (void *) __get_free_page(GFP_KERNEL);
 695        if (hwarc->rd_buffer == NULL) {
 696                dev_err(dev, "Unable to allocate notification's read buffer\n");
 697                goto error_rd_buffer;
 698        }
 699        hwarc->neep_urb = usb_alloc_urb(0, GFP_KERNEL);
 700        if (hwarc->neep_urb == NULL) {
 701                dev_err(dev, "Unable to allocate notification URB\n");
 702                goto error_urb_alloc;
 703        }
 704        usb_fill_int_urb(hwarc->neep_urb, usb_dev,
 705                         usb_rcvintpipe(usb_dev, epd->bEndpointAddress),
 706                         hwarc->rd_buffer, PAGE_SIZE,
 707                         hwarc_neep_cb, hwarc, epd->bInterval);
 708        result = usb_submit_urb(hwarc->neep_urb, GFP_ATOMIC);
 709        if (result < 0) {
 710                dev_err(dev, "Cannot submit notification URB: %d\n", result);
 711                goto error_neep_submit;
 712        }
 713        return 0;
 714
 715error_neep_submit:
 716        usb_free_urb(hwarc->neep_urb);
 717error_urb_alloc:
 718        free_page((unsigned long)hwarc->rd_buffer);
 719error_rd_buffer:
 720        return -ENOMEM;
 721}
 722
 723
 724/** Clean up all the notification endpoint resources */
 725static void hwarc_neep_release(struct uwb_rc *rc)
 726{
 727        struct hwarc *hwarc = rc->priv;
 728
 729        usb_kill_urb(hwarc->neep_urb);
 730        usb_free_urb(hwarc->neep_urb);
 731        free_page((unsigned long)hwarc->rd_buffer);
 732}
 733
 734/**
 735 * Get the version from class-specific descriptor
 736 *
 737 * NOTE: this descriptor comes with the big bundled configuration
 738 *       descriptor that includes the interfaces' and endpoints', so
 739 *       we just look for it in the cached copy kept by the USB stack.
 740 *
 741 * NOTE2: We convert LE fields to CPU order.
 742 */
 743static int hwarc_get_version(struct uwb_rc *rc)
 744{
 745        int result;
 746
 747        struct hwarc *hwarc = rc->priv;
 748        struct uwb_rc_control_intf_class_desc *descr;
 749        struct device *dev = &rc->uwb_dev.dev;
 750        struct usb_device *usb_dev = hwarc->usb_dev;
 751        char *itr;
 752        struct usb_descriptor_header *hdr;
 753        size_t itr_size, actconfig_idx;
 754        u16 version;
 755
 756        actconfig_idx = (usb_dev->actconfig - usb_dev->config) /
 757                sizeof(usb_dev->config[0]);
 758        itr = usb_dev->rawdescriptors[actconfig_idx];
 759        itr_size = le16_to_cpu(usb_dev->actconfig->desc.wTotalLength);
 760        while (itr_size >= sizeof(*hdr)) {
 761                hdr = (struct usb_descriptor_header *) itr;
 762                d_printf(3, dev, "Extra device descriptor: "
 763                         "type %02x/%u bytes @ %zu (%zu left)\n",
 764                         hdr->bDescriptorType, hdr->bLength,
 765                         (itr - usb_dev->rawdescriptors[actconfig_idx]),
 766                         itr_size);
 767                if (hdr->bDescriptorType == USB_DT_CS_RADIO_CONTROL)
 768                        goto found;
 769                itr += hdr->bLength;
 770                itr_size -= hdr->bLength;
 771        }
 772        dev_err(dev, "cannot find Radio Control Interface Class descriptor\n");
 773        return -ENODEV;
 774
 775found:
 776        result = -EINVAL;
 777        if (hdr->bLength > itr_size) {  /* is it available? */
 778                dev_err(dev, "incomplete Radio Control Interface Class "
 779                        "descriptor (%zu bytes left, %u needed)\n",
 780                        itr_size, hdr->bLength);
 781                goto error;
 782        }
 783        if (hdr->bLength < sizeof(*descr)) {
 784                dev_err(dev, "short Radio Control Interface Class "
 785                        "descriptor\n");
 786                goto error;
 787        }
 788        descr = (struct uwb_rc_control_intf_class_desc *) hdr;
 789        /* Make LE fields CPU order */
 790        version = __le16_to_cpu(descr->bcdRCIVersion);
 791        if (version != 0x0100) {
 792                dev_err(dev, "Device reports protocol version 0x%04x. We "
 793                        "do not support that. \n", version);
 794                result = -EINVAL;
 795                goto error;
 796        }
 797        rc->version = version;
 798        d_printf(3, dev, "Device supports WUSB protocol version 0x%04x \n",
 799                 rc->version);
 800        result = 0;
 801error:
 802        return result;
 803}
 804
 805/*
 806 * By creating a 'uwb_rc', we have a reference on it -- that reference
 807 * is the one we drop when we disconnect.
 808 *
 809 * No need to switch altsettings; according to WUSB1.0[8.6.1.1], there
 810 * is only one altsetting allowed.
 811 */
 812static int hwarc_probe(struct usb_interface *iface,
 813                       const struct usb_device_id *id)
 814{
 815        int result;
 816        struct uwb_rc *uwb_rc;
 817        struct hwarc *hwarc;
 818        struct device *dev = &iface->dev;
 819
 820        result = -ENOMEM;
 821        uwb_rc = uwb_rc_alloc();
 822        if (uwb_rc == NULL) {
 823                dev_err(dev, "unable to allocate RC instance\n");
 824                goto error_rc_alloc;
 825        }
 826        hwarc = kzalloc(sizeof(*hwarc), GFP_KERNEL);
 827        if (hwarc == NULL) {
 828                dev_err(dev, "unable to allocate HWA RC instance\n");
 829                goto error_alloc;
 830        }
 831        hwarc_init(hwarc);
 832        hwarc->usb_dev = usb_get_dev(interface_to_usbdev(iface));
 833        hwarc->usb_iface = usb_get_intf(iface);
 834        hwarc->uwb_rc = uwb_rc;
 835
 836        uwb_rc->owner = THIS_MODULE;
 837        uwb_rc->start = hwarc_neep_init;
 838        uwb_rc->stop  = hwarc_neep_release;
 839        uwb_rc->cmd   = hwarc_cmd;
 840        uwb_rc->reset = hwarc_reset;
 841        if (id->driver_info & WUSB_QUIRK_WHCI_CMD_EVT) {
 842                uwb_rc->filter_cmd   = NULL;
 843                uwb_rc->filter_event = NULL;
 844        } else {
 845                uwb_rc->filter_cmd   = hwarc_filter_cmd;
 846                uwb_rc->filter_event = hwarc_filter_event;
 847        }
 848
 849        result = uwb_rc_add(uwb_rc, dev, hwarc);
 850        if (result < 0)
 851                goto error_rc_add;
 852        result = hwarc_get_version(uwb_rc);
 853        if (result < 0) {
 854                dev_err(dev, "cannot retrieve version of RC \n");
 855                goto error_get_version;
 856        }
 857        usb_set_intfdata(iface, hwarc);
 858        return 0;
 859
 860error_get_version:
 861        uwb_rc_rm(uwb_rc);
 862error_rc_add:
 863        usb_put_intf(iface);
 864        usb_put_dev(hwarc->usb_dev);
 865error_alloc:
 866        uwb_rc_put(uwb_rc);
 867error_rc_alloc:
 868        return result;
 869}
 870
 871static void hwarc_disconnect(struct usb_interface *iface)
 872{
 873        struct hwarc *hwarc = usb_get_intfdata(iface);
 874        struct uwb_rc *uwb_rc = hwarc->uwb_rc;
 875
 876        usb_set_intfdata(hwarc->usb_iface, NULL);
 877        uwb_rc_rm(uwb_rc);
 878        usb_put_intf(hwarc->usb_iface);
 879        usb_put_dev(hwarc->usb_dev);
 880        d_printf(1, &hwarc->usb_iface->dev, "freed hwarc %p\n", hwarc);
 881        kfree(hwarc);
 882        uwb_rc_put(uwb_rc);     /* when creating the device, refcount = 1 */
 883}
 884
 885/** USB device ID's that we handle */
 886static struct usb_device_id hwarc_id_table[] = {
 887        /* D-Link DUB-1210 */
 888        { USB_DEVICE_AND_INTERFACE_INFO(0x07d1, 0x3d02, 0xe0, 0x01, 0x02),
 889          .driver_info = WUSB_QUIRK_WHCI_CMD_EVT },
 890        /* Intel i1480 (using firmware 1.3PA2-20070828) */
 891        { USB_DEVICE_AND_INTERFACE_INFO(0x8086, 0x0c3b, 0xe0, 0x01, 0x02),
 892          .driver_info = WUSB_QUIRK_WHCI_CMD_EVT },
 893        /* Generic match for the Radio Control interface */
 894        { USB_INTERFACE_INFO(0xe0, 0x01, 0x02), },
 895        { },
 896};
 897MODULE_DEVICE_TABLE(usb, hwarc_id_table);
 898
 899static struct usb_driver hwarc_driver = {
 900        .name =         "hwa-rc",
 901        .probe =        hwarc_probe,
 902        .disconnect =   hwarc_disconnect,
 903        .id_table =     hwarc_id_table,
 904};
 905
 906static int __init hwarc_driver_init(void)
 907{
 908        int result;
 909        result = usb_register(&hwarc_driver);
 910        if (result < 0)
 911                printk(KERN_ERR "HWA-RC: Cannot register USB driver: %d\n",
 912                       result);
 913        return result;
 914
 915}
 916module_init(hwarc_driver_init);
 917
 918static void __exit hwarc_driver_exit(void)
 919{
 920        usb_deregister(&hwarc_driver);
 921}
 922module_exit(hwarc_driver_exit);
 923
 924MODULE_AUTHOR("Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>");
 925MODULE_DESCRIPTION("Host Wireless Adapter Radio Control Driver");
 926MODULE_LICENSE("GPL");
 927