FreeBSD/Linux Kernel Cross Reference
sys/dev/iwm/if_iwm_mac_ctxt.c

     /*      $OpenBSD: if_iwm.c,v 1.39 2015/03/23 00:35:19 jsg Exp $ */
     
     /*
      * Copyright (c) 2014 genua mbh <info@genua.de>
      * Copyright (c) 2014 Fixup Software Ltd.
      *
      * Permission to use, copy, modify, and distribute this software for any
      * purpose with or without fee is hereby granted, provided that the above
      * copyright notice and this permission notice appear in all copies.
     *
     * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
     * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
     * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     */
    
    /*-
     * Based on BSD-licensed source modules in the Linux iwlwifi driver,
     * which were used as the reference documentation for this implementation.
     *
     * Driver version we are currently based off of is
     * Linux 3.14.3 (tag id a2df521e42b1d9a23f620ac79dbfe8655a8391dd)
     *
     ***********************************************************************
     *
     * This file is provided under a dual BSD/GPLv2 license.  When using or
     * redistributing this file, you may do so under either license.
     *
     * GPL LICENSE SUMMARY
     *
     * Copyright(c) 2007 - 2013 Intel Corporation. All rights reserved.
     *
     * This program is free software; you can redistribute it and/or modify
     * it under the terms of version 2 of the GNU General Public License as
     * published by the Free Software Foundation.
     *
     * This program is distributed in the hope that it will be useful, but
     * WITHOUT ANY WARRANTY; without even the implied warranty of
     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     * General Public License for more details.
     *
     * You should have received a copy of the GNU General Public License
     * along with this program; if not, write to the Free Software
     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110,
     * USA
     *
     * The full GNU General Public License is included in this distribution
     * in the file called COPYING.
     *
     * Contact Information:
     *  Intel Linux Wireless <ilw@linux.intel.com>
     * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
     *
     *
     * BSD LICENSE
     *
     * Copyright(c) 2005 - 2013 Intel Corporation. All rights reserved.
     * All rights reserved.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     *
     *  * Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     *  * Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in
     *    the documentation and/or other materials provided with the
     *    distribution.
     *  * Neither the name Intel Corporation nor the names of its
     *    contributors may be used to endorse or promote products derived
     *    from this software without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     */
    
    /*-
     * Copyright (c) 2007-2010 Damien Bergamini <damien.bergamini@free.fr>
     *
     * Permission to use, copy, modify, and distribute this software for any
     * purpose with or without fee is hereby granted, provided that the above
     * copyright notice and this permission notice appear in all copies.
     *
     * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
     * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
    * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
    */
   #include <sys/cdefs.h>
   __FBSDID("$FreeBSD$");
   
   #include "opt_wlan.h"
   #include "opt_iwm.h"
   
   #include <sys/param.h>
   #include <sys/bus.h>
   #include <sys/conf.h>
   #include <sys/endian.h>
   #include <sys/firmware.h>
   #include <sys/kernel.h>
   #include <sys/malloc.h>
   #include <sys/mbuf.h>
   #include <sys/mutex.h>
   #include <sys/module.h>
   #include <sys/proc.h>
   #include <sys/rman.h>
   #include <sys/socket.h>
   #include <sys/sockio.h>
   #include <sys/sysctl.h>
   #include <sys/linker.h>
   
   #include <machine/bus.h>
   #include <machine/endian.h>
   #include <machine/resource.h>
   
   #include <dev/pci/pcivar.h>
   #include <dev/pci/pcireg.h>
   
   #include <net/bpf.h>
   
   #include <net/if.h>
   #include <net/if_var.h>
   #include <net/if_arp.h>
   #include <net/if_dl.h>
   #include <net/if_media.h>
   #include <net/if_types.h>
   
   #include <netinet/in.h>
   #include <netinet/in_systm.h>
   #include <netinet/if_ether.h>
   #include <netinet/ip.h>
   
   #include <net80211/ieee80211_var.h>
   #include <net80211/ieee80211_regdomain.h>
   #include <net80211/ieee80211_ratectl.h>
   #include <net80211/ieee80211_radiotap.h>
   
   #include <dev/iwm/if_iwmreg.h>
   #include <dev/iwm/if_iwmvar.h>
   #include <dev/iwm/if_iwm_debug.h>
   #include <dev/iwm/if_iwm_util.h>
   #include <dev/iwm/if_iwm_mac_ctxt.h>
   
   /*
    * BEGIN mvm/mac-ctxt.c
    */
   
   const uint8_t iwm_ac_to_tx_fifo[] = {
           IWM_TX_FIFO_BE,
           IWM_TX_FIFO_BK,
           IWM_TX_FIFO_VI,
           IWM_TX_FIFO_VO,
   };
   
   static void
   iwm_ack_rates(struct iwm_softc *sc, int is2ghz,
           int *cck_rates, int *ofdm_rates, struct iwm_node *in)
   {
           int lowest_present_ofdm = 100;
           int lowest_present_cck = 100;
           uint8_t cck = 0;
           uint8_t ofdm = 0;
           int i;
           struct ieee80211_rateset *rs = &in->in_ni.ni_rates;
   
           if (is2ghz) {
                   for (i = IWM_FIRST_CCK_RATE; i <= IWM_LAST_CCK_RATE; i++) {
                           if ((iwm_ridx2rate(rs, i) & IEEE80211_RATE_BASIC) == 0)
                                   continue;
                           cck |= (1 << i);
                           if (lowest_present_cck > i)
                                   lowest_present_cck = i;
                   }
           }
           for (i = IWM_FIRST_OFDM_RATE; i <= IWM_LAST_NON_HT_RATE; i++) {
                   if ((iwm_ridx2rate(rs, i) & IEEE80211_RATE_BASIC) == 0)
                           continue;
                   ofdm |= (1 << (i - IWM_FIRST_OFDM_RATE));
                   if (lowest_present_ofdm > i)
                           lowest_present_ofdm = i;
           }
   
           /*
            * Now we've got the basic rates as bitmaps in the ofdm and cck
            * variables. This isn't sufficient though, as there might not
            * be all the right rates in the bitmap. E.g. if the only basic
            * rates are 5.5 Mbps and 11 Mbps, we still need to add 1 Mbps
            * and 6 Mbps because the 802.11-2007 standard says in 9.6:
            *
            *    [...] a STA responding to a received frame shall transmit
            *    its Control Response frame [...] at the highest rate in the
            *    BSSBasicRateSet parameter that is less than or equal to the
            *    rate of the immediately previous frame in the frame exchange
            *    sequence ([...]) and that is of the same modulation class
            *    ([...]) as the received frame. If no rate contained in the
            *    BSSBasicRateSet parameter meets these conditions, then the
            *    control frame sent in response to a received frame shall be
            *    transmitted at the highest mandatory rate of the PHY that is
            *    less than or equal to the rate of the received frame, and
            *    that is of the same modulation class as the received frame.
            *
            * As a consequence, we need to add all mandatory rates that are
            * lower than all of the basic rates to these bitmaps.
            */
   
           if (IWM_RATE_24M_INDEX < lowest_present_ofdm)
                   ofdm |= IWM_RATE_BIT_MSK(24) >> IWM_FIRST_OFDM_RATE;
           if (IWM_RATE_12M_INDEX < lowest_present_ofdm)
                   ofdm |= IWM_RATE_BIT_MSK(12) >> IWM_FIRST_OFDM_RATE;
           /* 6M already there or needed so always add */
           ofdm |= IWM_RATE_BIT_MSK(6) >> IWM_FIRST_OFDM_RATE;
   
           /*
            * CCK is a bit more complex with DSSS vs. HR/DSSS vs. ERP.
            * Note, however:
            *  - if no CCK rates are basic, it must be ERP since there must
            *    be some basic rates at all, so they're OFDM => ERP PHY
            *    (or we're in 5 GHz, and the cck bitmap will never be used)
            *  - if 11M is a basic rate, it must be ERP as well, so add 5.5M
            *  - if 5.5M is basic, 1M and 2M are mandatory
            *  - if 2M is basic, 1M is mandatory
            *  - if 1M is basic, that's the only valid ACK rate.
            * As a consequence, it's not as complicated as it sounds, just add
            * any lower rates to the ACK rate bitmap.
            */
           if (IWM_RATE_11M_INDEX < lowest_present_cck)
                   cck |= IWM_RATE_BIT_MSK(11) >> IWM_FIRST_CCK_RATE;
           if (IWM_RATE_5M_INDEX < lowest_present_cck)
                   cck |= IWM_RATE_BIT_MSK(5) >> IWM_FIRST_CCK_RATE;
           if (IWM_RATE_2M_INDEX < lowest_present_cck)
                   cck |= IWM_RATE_BIT_MSK(2) >> IWM_FIRST_CCK_RATE;
           /* 1M already there or needed so always add */
           cck |= IWM_RATE_BIT_MSK(1) >> IWM_FIRST_CCK_RATE;
   
           *cck_rates = cck;
           *ofdm_rates = ofdm;
   }
   
   static void
   iwm_mac_ctxt_cmd_common(struct iwm_softc *sc, struct iwm_node *in,
           struct iwm_mac_ctx_cmd *cmd, uint32_t action)
   {
           struct ieee80211com *ic = &sc->sc_ic;
           struct ieee80211vap *vap = TAILQ_FIRST(&ic->ic_vaps);
           struct ieee80211_node *ni = vap->iv_bss;
           struct iwm_vap *ivp = IWM_VAP(vap);
           int cck_ack_rates, ofdm_ack_rates;
           int i;
           int is2ghz;
   
           /*
            * id is the MAC address ID - something to do with MAC filtering.
            * color - not sure.
            *
            * These are both functions of the vap, not of the node.
            * So, for now, hard-code both to 0 (default).
            */
           cmd->id_and_color = htole32(IWM_FW_CMD_ID_AND_COLOR(ivp->id,
               ivp->color));
           cmd->action = htole32(action);
   
           cmd->mac_type = htole32(IWM_FW_MAC_TYPE_BSS_STA);
   
           /*
            * The TSF ID is one of four TSF tracking resources in the firmware.
            * Read the iwlwifi/mvm code for more details.
            *
            * For now, just hard-code it to TSF tracking ID 0; we only support
            * a single STA mode VAP.
            *
            * It's per-vap, not per-node.
            */
           cmd->tsf_id = htole32(IWM_DEFAULT_TSFID);
   
           IEEE80211_ADDR_COPY(cmd->node_addr, vap->iv_myaddr);
   
           /*
            * XXX should we error out if in_assoc is 1 and ni == NULL?
            */
   #if 0
           if (in->in_assoc) {
                   IEEE80211_ADDR_COPY(cmd->bssid_addr, ni->ni_bssid);
           } else {
                   /* eth broadcast address */
                   IEEE80211_ADDR_COPY(cmd->bssid_addr, ieee80211broadcastaddr);
           }
   #else
           /*
            * XXX This workaround makes the firmware behave more correctly once
            *     we are associated, regularly giving us statistics notifications,
            *     as well as signaling missed beacons to us.
            *     Since we only call iwm_mac_ctxt_add() and
            *     iwm_mac_ctxt_changed() when already authenticating or
            *     associating, ni->ni_bssid should always make sense here.
            */
           if (ivp->iv_auth) {
                   IEEE80211_ADDR_COPY(cmd->bssid_addr, ni->ni_bssid);
           } else {
                   /* XXX Or maybe all zeroes address? */
                   IEEE80211_ADDR_COPY(cmd->bssid_addr, ieee80211broadcastaddr);
           }
   #endif
   
           /*
            * Default to 2ghz if no node information is given.
            */
           if (in && in->in_ni.ni_chan != IEEE80211_CHAN_ANYC) {
                   is2ghz = !! IEEE80211_IS_CHAN_2GHZ(in->in_ni.ni_chan);
           } else {
                   is2ghz = 1;
           }
           iwm_ack_rates(sc, is2ghz, &cck_ack_rates, &ofdm_ack_rates, in);
           cmd->cck_rates = htole32(cck_ack_rates);
           cmd->ofdm_rates = htole32(ofdm_ack_rates);
   
           cmd->cck_short_preamble
               = htole32((ic->ic_flags & IEEE80211_F_SHPREAMBLE)
                 ? IWM_MAC_FLG_SHORT_PREAMBLE : 0);
           cmd->short_slot
               = htole32((ic->ic_flags & IEEE80211_F_SHSLOT)
                 ? IWM_MAC_FLG_SHORT_SLOT : 0);
   
           /*
            * XXX TODO: if we're doing QOS..
            * cmd->qos_flags |= cpu_to_le32(MAC_QOS_FLG_UPDATE_EDCA)
            */
   
           for (i = 0; i < WME_NUM_AC; i++) {
                   uint8_t txf = iwm_ac_to_tx_fifo[i];
   
                   cmd->ac[txf].cw_min = htole16(ivp->queue_params[i].cw_min);
                   cmd->ac[txf].cw_max = htole16(ivp->queue_params[i].cw_max);
                   cmd->ac[txf].edca_txop =
                       htole16(ivp->queue_params[i].edca_txop);
                   cmd->ac[txf].aifsn = ivp->queue_params[i].aifsn;
                   cmd->ac[txf].fifos_mask = (1 << txf);
           }
   
           if (ivp->have_wme)
                   cmd->qos_flags |= htole32(IWM_MAC_QOS_FLG_UPDATE_EDCA);
   
           if (ic->ic_flags & IEEE80211_F_USEPROT)
                   cmd->protection_flags |= htole32(IWM_MAC_PROT_FLG_TGG_PROTECT);
   
           cmd->filter_flags = htole32(IWM_MAC_FILTER_ACCEPT_GRP);
   }
   
   static int
   iwm_mac_ctxt_send_cmd(struct iwm_softc *sc, struct iwm_mac_ctx_cmd *cmd)
   {
           int ret = iwm_send_cmd_pdu(sc, IWM_MAC_CONTEXT_CMD, IWM_CMD_SYNC,
                                          sizeof(*cmd), cmd);
           if (ret)
                   device_printf(sc->sc_dev,
                       "%s: Failed to send MAC context (action:%d): %d\n",
                       __func__, le32toh(cmd->action), ret);
           return ret;
   }
   
   /*
    * Fill the specific data for mac context of type station or p2p client
    */
   static void
   iwm_mac_ctxt_cmd_fill_sta(struct iwm_softc *sc, struct iwm_node *in,
           struct iwm_mac_data_sta *ctxt_sta, int force_assoc_off)
   {
           struct ieee80211_node *ni = &in->in_ni;
           unsigned dtim_period, dtim_count;
           struct ieee80211com *ic = &sc->sc_ic;
           struct ieee80211vap *vap = TAILQ_FIRST(&ic->ic_vaps);
   
           /* will this work? */
           dtim_period = vap->iv_dtim_period;
           dtim_count = vap->iv_dtim_count;
           IWM_DPRINTF(sc, IWM_DEBUG_RESET | IWM_DEBUG_BEACON | IWM_DEBUG_CMD,
               "%s: force_assoc_off=%d\n", __func__, force_assoc_off);
           IWM_DPRINTF(sc, IWM_DEBUG_RESET | IWM_DEBUG_BEACON | IWM_DEBUG_CMD,
               "DTIM: period=%d count=%d\n", dtim_period, dtim_count);
           IWM_DPRINTF(sc, IWM_DEBUG_RESET | IWM_DEBUG_BEACON | IWM_DEBUG_CMD,
               "BEACON: tsf: %llu, ni_intval=%d\n",
               (unsigned long long) le64toh(ni->ni_tstamp.tsf),
               ni->ni_intval);
   
           /* We need the dtim_period to set the MAC as associated */
           if (in->in_assoc && dtim_period && !force_assoc_off) {
                   uint64_t tsf;
                   uint32_t dtim_offs;
   
                   /*
                    * The DTIM count counts down, so when it is N that means N
                    * more beacon intervals happen until the DTIM TBTT. Therefore
                    * add this to the current time. If that ends up being in the
                    * future, the firmware will handle it.
                    *
                    * Also note that the system_timestamp (which we get here as
                    * "sync_device_ts") and TSF timestamp aren't at exactly the
                    * same offset in the frame -- the TSF is at the first symbol
                    * of the TSF, the system timestamp is at signal acquisition
                    * time. This means there's an offset between them of at most
                    * a few hundred microseconds (24 * 8 bits + PLCP time gives
                    * 384us in the longest case), this is currently not relevant
                    * as the firmware wakes up around 2ms before the TBTT.
                    */
                   dtim_offs = dtim_count * ni->ni_intval;
                   /* convert TU to usecs */
                   dtim_offs *= 1024;
   
                   /*
                    * net80211: TSF is in 802.11 order, so convert up to local
                    * ordering before we manipulate things.
                    */
                   tsf = le64toh(ni->ni_tstamp.tsf);
   
                   ctxt_sta->dtim_tsf = htole64(tsf + dtim_offs);
                   ctxt_sta->dtim_time = htole32(tsf + dtim_offs);
   
                   IWM_DPRINTF(sc, IWM_DEBUG_RESET | IWM_DEBUG_BEACON | IWM_DEBUG_CMD,
                       "DTIM TBTT is 0x%llx/0x%x, offset %d\n",
                       (long long)le64toh(ctxt_sta->dtim_tsf),
                       le32toh(ctxt_sta->dtim_time), dtim_offs);
   
                   ctxt_sta->is_assoc = htole32(1);
           } else {
                   ctxt_sta->is_assoc = htole32(0);
           }
   
           IWM_DPRINTF(sc, IWM_DEBUG_RESET | IWM_DEBUG_CMD | IWM_DEBUG_BEACON,
               "%s: ni_intval: %d, bi_reciprocal: %d, dtim_interval: %d, dtim_reciprocal: %d\n",
               __func__,
               ni->ni_intval,
               iwm_reciprocal(ni->ni_intval),
               ni->ni_intval * dtim_period,
               iwm_reciprocal(ni->ni_intval * dtim_period));
   
           ctxt_sta->bi = htole32(ni->ni_intval);
           ctxt_sta->bi_reciprocal = htole32(iwm_reciprocal(ni->ni_intval));
           ctxt_sta->dtim_interval = htole32(ni->ni_intval * dtim_period);
           ctxt_sta->dtim_reciprocal =
               htole32(iwm_reciprocal(ni->ni_intval * dtim_period));
   
           /* 10 = CONN_MAX_LISTEN_INTERVAL */
           ctxt_sta->listen_interval = htole32(10);
           IWM_DPRINTF(sc, IWM_DEBUG_RESET | IWM_DEBUG_CMD | IWM_DEBUG_BEACON,
               "%s: associd=%d\n", __func__, IEEE80211_AID(ni->ni_associd));
           ctxt_sta->assoc_id = htole32(IEEE80211_AID(ni->ni_associd));
   }
   
   static int
   iwm_mac_ctxt_cmd_station(struct iwm_softc *sc, struct ieee80211vap *vap,
           uint32_t action)
   {
           struct ieee80211_node *ni = vap->iv_bss;
           struct iwm_node *in = IWM_NODE(ni);
           struct iwm_mac_ctx_cmd cmd = {};
   
           IWM_DPRINTF(sc, IWM_DEBUG_RESET,
               "%s: called; action=%d\n", __func__, action);
   
           /* Fill the common data for all mac context types */
           iwm_mac_ctxt_cmd_common(sc, in, &cmd, action);
   
           /* Allow beacons to pass through as long as we are not associated,or we
            * do not have dtim period information */
           if (!in->in_assoc || !vap->iv_dtim_period)
                   cmd.filter_flags |= htole32(IWM_MAC_FILTER_IN_BEACON);
           else
                   cmd.filter_flags &= ~htole32(IWM_MAC_FILTER_IN_BEACON);
   
           /* Fill the data specific for station mode */
           iwm_mac_ctxt_cmd_fill_sta(sc, in,
               &cmd.sta, action == IWM_FW_CTXT_ACTION_ADD);
   
           return iwm_mac_ctxt_send_cmd(sc, &cmd);
   }
   
   static int
   iwm_mac_ctx_send(struct iwm_softc *sc, struct ieee80211vap *vap,
       uint32_t action)
   {
           return iwm_mac_ctxt_cmd_station(sc, vap, action);
   }
   
   int
   iwm_mac_ctxt_add(struct iwm_softc *sc, struct ieee80211vap *vap)
   {
           struct iwm_vap *iv = IWM_VAP(vap);
           int ret;
   
           if (iv->is_uploaded != 0) {
                   device_printf(sc->sc_dev, "%s: called; uploaded != 0\n",
                       __func__);
                   return (EIO);
           }
   
           ret = iwm_mac_ctx_send(sc, vap, IWM_FW_CTXT_ACTION_ADD);
           if (ret)
                   return (ret);
           iv->is_uploaded = 1;
           return (0);
   }
   
   int
   iwm_mac_ctxt_changed(struct iwm_softc *sc, struct ieee80211vap *vap)
   {
           struct iwm_vap *iv = IWM_VAP(vap);
   
           if (iv->is_uploaded == 0) {
                   device_printf(sc->sc_dev, "%s: called; uploaded = 0\n",
                       __func__);
                   return (EIO);
           }
           return iwm_mac_ctx_send(sc, vap, IWM_FW_CTXT_ACTION_MODIFY);
   }
   
   #if 0
   static int
   iwm_mac_ctxt_remove(struct iwm_softc *sc, struct iwm_node *in)
   {
           struct iwm_mac_ctx_cmd cmd;
           int ret;
   
           if (!in->in_uploaded) {
                   device_printf(sc->sc_dev,
                       "attempt to remove !uploaded node %p", in);
                   return EIO;
           }
   
           memset(&cmd, 0, sizeof(cmd));
   
           cmd.id_and_color = htole32(IWM_FW_CMD_ID_AND_COLOR(IWM_DEFAULT_MACID,
               IWM_DEFAULT_COLOR));
           cmd.action = htole32(IWM_FW_CTXT_ACTION_REMOVE);
   
           ret = iwm_send_cmd_pdu(sc,
               IWM_MAC_CONTEXT_CMD, IWM_CMD_SYNC, sizeof(cmd), &cmd);
           if (ret) {
                   device_printf(sc->sc_dev,
                       "Failed to remove MAC context: %d\n", ret);
                   return ret;
           }
           in->in_uploaded = 0;
   
           return 0;
   }
   #endif

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