linux/drivers/net/wireless/rt2x00/rt2x00mac.c

707 lines
20 KiB
C

/*
Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com>
<http://rt2x00.serialmonkey.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
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.,
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/*
Module: rt2x00mac
Abstract: rt2x00 generic mac80211 routines.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include "rt2x00.h"
#include "rt2x00lib.h"
static int rt2x00mac_tx_rts_cts(struct rt2x00_dev *rt2x00dev,
struct data_queue *queue,
struct sk_buff *frag_skb)
{
struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(frag_skb);
struct ieee80211_tx_info *rts_info;
struct sk_buff *skb;
unsigned int data_length;
int retval = 0;
if (tx_info->control.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT)
data_length = sizeof(struct ieee80211_cts);
else
data_length = sizeof(struct ieee80211_rts);
skb = dev_alloc_skb(data_length + rt2x00dev->hw->extra_tx_headroom);
if (unlikely(!skb)) {
WARNING(rt2x00dev, "Failed to create RTS/CTS frame.\n");
return -ENOMEM;
}
skb_reserve(skb, rt2x00dev->hw->extra_tx_headroom);
skb_put(skb, data_length);
/*
* Copy TX information over from original frame to
* RTS/CTS frame. Note that we set the no encryption flag
* since we don't want this frame to be encrypted.
* RTS frames should be acked, while CTS-to-self frames
* should not. The ready for TX flag is cleared to prevent
* it being automatically send when the descriptor is
* written to the hardware.
*/
memcpy(skb->cb, frag_skb->cb, sizeof(skb->cb));
rts_info = IEEE80211_SKB_CB(skb);
rts_info->control.rates[0].flags &= ~IEEE80211_TX_RC_USE_RTS_CTS;
rts_info->control.rates[0].flags &= ~IEEE80211_TX_RC_USE_CTS_PROTECT;
if (tx_info->control.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT)
rts_info->flags |= IEEE80211_TX_CTL_NO_ACK;
else
rts_info->flags &= ~IEEE80211_TX_CTL_NO_ACK;
/* Disable hardware encryption */
rts_info->control.hw_key = NULL;
/*
* RTS/CTS frame should use the length of the frame plus any
* encryption overhead that will be added by the hardware.
*/
data_length += rt2x00crypto_tx_overhead(rt2x00dev, skb);
if (tx_info->control.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT)
ieee80211_ctstoself_get(rt2x00dev->hw, tx_info->control.vif,
frag_skb->data, data_length, tx_info,
(struct ieee80211_cts *)(skb->data));
else
ieee80211_rts_get(rt2x00dev->hw, tx_info->control.vif,
frag_skb->data, data_length, tx_info,
(struct ieee80211_rts *)(skb->data));
retval = rt2x00queue_write_tx_frame(queue, skb, true);
if (retval) {
dev_kfree_skb_any(skb);
WARNING(rt2x00dev, "Failed to send RTS/CTS frame.\n");
}
return retval;
}
int rt2x00mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
{
struct rt2x00_dev *rt2x00dev = hw->priv;
struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
enum data_queue_qid qid = skb_get_queue_mapping(skb);
struct data_queue *queue = NULL;
/*
* Mac80211 might be calling this function while we are trying
* to remove the device or perhaps suspending it.
* Note that we can only stop the TX queues inside the TX path
* due to possible race conditions in mac80211.
*/
if (!test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
goto exit_fail;
/*
* Determine which queue to put packet on.
*/
if (tx_info->flags & IEEE80211_TX_CTL_SEND_AFTER_DTIM &&
test_bit(DRIVER_REQUIRE_ATIM_QUEUE, &rt2x00dev->flags))
queue = rt2x00queue_get_queue(rt2x00dev, QID_ATIM);
else
queue = rt2x00queue_get_queue(rt2x00dev, qid);
if (unlikely(!queue)) {
ERROR(rt2x00dev,
"Attempt to send packet over invalid queue %d.\n"
"Please file bug report to %s.\n", qid, DRV_PROJECT);
goto exit_fail;
}
/*
* If CTS/RTS is required. create and queue that frame first.
* Make sure we have at least enough entries available to send
* this CTS/RTS frame as well as the data frame.
* Note that when the driver has set the set_rts_threshold()
* callback function it doesn't need software generation of
* either RTS or CTS-to-self frame and handles everything
* inside the hardware.
*/
if ((tx_info->control.rates[0].flags & (IEEE80211_TX_RC_USE_RTS_CTS |
IEEE80211_TX_RC_USE_CTS_PROTECT)) &&
!rt2x00dev->ops->hw->set_rts_threshold) {
if (rt2x00queue_available(queue) <= 1)
goto exit_fail;
if (rt2x00mac_tx_rts_cts(rt2x00dev, queue, skb))
goto exit_fail;
}
if (rt2x00queue_write_tx_frame(queue, skb, false))
goto exit_fail;
if (rt2x00queue_threshold(queue))
rt2x00queue_pause_queue(queue);
return NETDEV_TX_OK;
exit_fail:
ieee80211_stop_queue(rt2x00dev->hw, qid);
dev_kfree_skb_any(skb);
return NETDEV_TX_OK;
}
EXPORT_SYMBOL_GPL(rt2x00mac_tx);
int rt2x00mac_start(struct ieee80211_hw *hw)
{
struct rt2x00_dev *rt2x00dev = hw->priv;
if (!test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
return 0;
return rt2x00lib_start(rt2x00dev);
}
EXPORT_SYMBOL_GPL(rt2x00mac_start);
void rt2x00mac_stop(struct ieee80211_hw *hw)
{
struct rt2x00_dev *rt2x00dev = hw->priv;
if (!test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
return;
rt2x00lib_stop(rt2x00dev);
}
EXPORT_SYMBOL_GPL(rt2x00mac_stop);
int rt2x00mac_add_interface(struct ieee80211_hw *hw,
struct ieee80211_vif *vif)
{
struct rt2x00_dev *rt2x00dev = hw->priv;
struct rt2x00_intf *intf = vif_to_intf(vif);
struct data_queue *queue = rt2x00queue_get_queue(rt2x00dev, QID_BEACON);
struct queue_entry *entry = NULL;
unsigned int i;
/*
* Don't allow interfaces to be added
* the device has disappeared.
*/
if (!test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags) ||
!test_bit(DEVICE_STATE_STARTED, &rt2x00dev->flags))
return -ENODEV;
switch (vif->type) {
case NL80211_IFTYPE_AP:
/*
* We don't support mixed combinations of
* sta and ap interfaces.
*/
if (rt2x00dev->intf_sta_count)
return -ENOBUFS;
/*
* Check if we exceeded the maximum amount
* of supported interfaces.
*/
if (rt2x00dev->intf_ap_count >= rt2x00dev->ops->max_ap_intf)
return -ENOBUFS;
break;
case NL80211_IFTYPE_STATION:
case NL80211_IFTYPE_ADHOC:
case NL80211_IFTYPE_MESH_POINT:
case NL80211_IFTYPE_WDS:
/*
* We don't support mixed combinations of
* sta and ap interfaces.
*/
if (rt2x00dev->intf_ap_count)
return -ENOBUFS;
/*
* Check if we exceeded the maximum amount
* of supported interfaces.
*/
if (rt2x00dev->intf_sta_count >= rt2x00dev->ops->max_sta_intf)
return -ENOBUFS;
break;
default:
return -EINVAL;
}
/*
* Loop through all beacon queues to find a free
* entry. Since there are as much beacon entries
* as the maximum interfaces, this search shouldn't
* fail.
*/
for (i = 0; i < queue->limit; i++) {
entry = &queue->entries[i];
if (!test_and_set_bit(ENTRY_BCN_ASSIGNED, &entry->flags))
break;
}
if (unlikely(i == queue->limit))
return -ENOBUFS;
/*
* We are now absolutely sure the interface can be created,
* increase interface count and start initialization.
*/
if (vif->type == NL80211_IFTYPE_AP)
rt2x00dev->intf_ap_count++;
else
rt2x00dev->intf_sta_count++;
spin_lock_init(&intf->seqlock);
mutex_init(&intf->beacon_skb_mutex);
intf->beacon = entry;
/*
* The MAC address must be configured after the device
* has been initialized. Otherwise the device can reset
* the MAC registers.
* The BSSID address must only be configured in AP mode,
* however we should not send an empty BSSID address for
* STA interfaces at this time, since this can cause
* invalid behavior in the device.
*/
rt2x00lib_config_intf(rt2x00dev, intf, vif->type,
vif->addr, NULL);
/*
* Some filters depend on the current working mode. We can force
* an update during the next configure_filter() run by mac80211 by
* resetting the current packet_filter state.
*/
rt2x00dev->packet_filter = 0;
return 0;
}
EXPORT_SYMBOL_GPL(rt2x00mac_add_interface);
void rt2x00mac_remove_interface(struct ieee80211_hw *hw,
struct ieee80211_vif *vif)
{
struct rt2x00_dev *rt2x00dev = hw->priv;
struct rt2x00_intf *intf = vif_to_intf(vif);
/*
* Don't allow interfaces to be remove while
* either the device has disappeared or when
* no interface is present.
*/
if (!test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags) ||
(vif->type == NL80211_IFTYPE_AP && !rt2x00dev->intf_ap_count) ||
(vif->type != NL80211_IFTYPE_AP && !rt2x00dev->intf_sta_count))
return;
if (vif->type == NL80211_IFTYPE_AP)
rt2x00dev->intf_ap_count--;
else
rt2x00dev->intf_sta_count--;
/*
* Release beacon entry so it is available for
* new interfaces again.
*/
clear_bit(ENTRY_BCN_ASSIGNED, &intf->beacon->flags);
/*
* Make sure the bssid and mac address registers
* are cleared to prevent false ACKing of frames.
*/
rt2x00lib_config_intf(rt2x00dev, intf,
NL80211_IFTYPE_UNSPECIFIED, NULL, NULL);
}
EXPORT_SYMBOL_GPL(rt2x00mac_remove_interface);
int rt2x00mac_config(struct ieee80211_hw *hw, u32 changed)
{
struct rt2x00_dev *rt2x00dev = hw->priv;
struct ieee80211_conf *conf = &hw->conf;
/*
* mac80211 might be calling this function while we are trying
* to remove the device or perhaps suspending it.
*/
if (!test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
return 0;
/*
* Some configuration parameters (e.g. channel and antenna values) can
* only be set when the radio is enabled, but do require the RX to
* be off. During this period we should keep link tuning enabled,
* if for any reason the link tuner must be reset, this will be
* handled by rt2x00lib_config().
*/
rt2x00queue_stop_queue(rt2x00dev->rx);
/*
* When we've just turned on the radio, we want to reprogram
* everything to ensure a consistent state
*/
rt2x00lib_config(rt2x00dev, conf, changed);
/*
* After the radio has been enabled we need to configure
* the antenna to the default settings. rt2x00lib_config_antenna()
* should determine if any action should be taken based on
* checking if diversity has been enabled or no antenna changes
* have been made since the last configuration change.
*/
rt2x00lib_config_antenna(rt2x00dev, rt2x00dev->default_ant);
/* Turn RX back on */
rt2x00queue_start_queue(rt2x00dev->rx);
return 0;
}
EXPORT_SYMBOL_GPL(rt2x00mac_config);
void rt2x00mac_configure_filter(struct ieee80211_hw *hw,
unsigned int changed_flags,
unsigned int *total_flags,
u64 multicast)
{
struct rt2x00_dev *rt2x00dev = hw->priv;
/*
* Mask off any flags we are going to ignore
* from the total_flags field.
*/
*total_flags &=
FIF_ALLMULTI |
FIF_FCSFAIL |
FIF_PLCPFAIL |
FIF_CONTROL |
FIF_PSPOLL |
FIF_OTHER_BSS |
FIF_PROMISC_IN_BSS;
/*
* Apply some rules to the filters:
* - Some filters imply different filters to be set.
* - Some things we can't filter out at all.
* - Multicast filter seems to kill broadcast traffic so never use it.
*/
*total_flags |= FIF_ALLMULTI;
if (*total_flags & FIF_OTHER_BSS ||
*total_flags & FIF_PROMISC_IN_BSS)
*total_flags |= FIF_PROMISC_IN_BSS | FIF_OTHER_BSS;
/*
* If the device has a single filter for all control frames,
* FIF_CONTROL and FIF_PSPOLL flags imply each other.
* And if the device has more than one filter for control frames
* of different types, but has no a separate filter for PS Poll frames,
* FIF_CONTROL flag implies FIF_PSPOLL.
*/
if (!test_bit(DRIVER_SUPPORT_CONTROL_FILTERS, &rt2x00dev->flags)) {
if (*total_flags & FIF_CONTROL || *total_flags & FIF_PSPOLL)
*total_flags |= FIF_CONTROL | FIF_PSPOLL;
}
if (!test_bit(DRIVER_SUPPORT_CONTROL_FILTER_PSPOLL, &rt2x00dev->flags)) {
if (*total_flags & FIF_CONTROL)
*total_flags |= FIF_PSPOLL;
}
/*
* Check if there is any work left for us.
*/
if (rt2x00dev->packet_filter == *total_flags)
return;
rt2x00dev->packet_filter = *total_flags;
rt2x00dev->ops->lib->config_filter(rt2x00dev, *total_flags);
}
EXPORT_SYMBOL_GPL(rt2x00mac_configure_filter);
static void rt2x00mac_set_tim_iter(void *data, u8 *mac,
struct ieee80211_vif *vif)
{
struct rt2x00_intf *intf = vif_to_intf(vif);
if (vif->type != NL80211_IFTYPE_AP &&
vif->type != NL80211_IFTYPE_ADHOC &&
vif->type != NL80211_IFTYPE_MESH_POINT &&
vif->type != NL80211_IFTYPE_WDS)
return;
set_bit(DELAYED_UPDATE_BEACON, &intf->delayed_flags);
}
int rt2x00mac_set_tim(struct ieee80211_hw *hw, struct ieee80211_sta *sta,
bool set)
{
struct rt2x00_dev *rt2x00dev = hw->priv;
if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
return 0;
ieee80211_iterate_active_interfaces_atomic(rt2x00dev->hw,
rt2x00mac_set_tim_iter,
rt2x00dev);
/* queue work to upodate the beacon template */
ieee80211_queue_work(rt2x00dev->hw, &rt2x00dev->intf_work);
return 0;
}
EXPORT_SYMBOL_GPL(rt2x00mac_set_tim);
#ifdef CONFIG_RT2X00_LIB_CRYPTO
static void memcpy_tkip(struct rt2x00lib_crypto *crypto, u8 *key, u8 key_len)
{
if (key_len > NL80211_TKIP_DATA_OFFSET_ENCR_KEY)
memcpy(crypto->key,
&key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY],
sizeof(crypto->key));
if (key_len > NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY)
memcpy(crypto->tx_mic,
&key[NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY],
sizeof(crypto->tx_mic));
if (key_len > NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY)
memcpy(crypto->rx_mic,
&key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY],
sizeof(crypto->rx_mic));
}
int rt2x00mac_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
struct ieee80211_vif *vif, struct ieee80211_sta *sta,
struct ieee80211_key_conf *key)
{
struct rt2x00_dev *rt2x00dev = hw->priv;
int (*set_key) (struct rt2x00_dev *rt2x00dev,
struct rt2x00lib_crypto *crypto,
struct ieee80211_key_conf *key);
struct rt2x00lib_crypto crypto;
static const u8 bcast_addr[ETH_ALEN] =
{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, };
if (!test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
return 0;
else if (!test_bit(CONFIG_SUPPORT_HW_CRYPTO, &rt2x00dev->flags))
return -EOPNOTSUPP;
else if (key->keylen > 32)
return -ENOSPC;
memset(&crypto, 0, sizeof(crypto));
/*
* When in STA mode, bssidx is always 0 otherwise local_address[5]
* contains the bss number, see BSS_ID_MASK comments for details.
*/
if (rt2x00dev->intf_sta_count)
crypto.bssidx = 0;
else
crypto.bssidx = vif->addr[5] & (rt2x00dev->ops->max_ap_intf - 1);
crypto.cipher = rt2x00crypto_key_to_cipher(key);
if (crypto.cipher == CIPHER_NONE)
return -EOPNOTSUPP;
crypto.cmd = cmd;
if (sta) {
/* some drivers need the AID */
crypto.aid = sta->aid;
crypto.address = sta->addr;
} else
crypto.address = bcast_addr;
if (crypto.cipher == CIPHER_TKIP)
memcpy_tkip(&crypto, &key->key[0], key->keylen);
else
memcpy(crypto.key, &key->key[0], key->keylen);
/*
* Each BSS has a maximum of 4 shared keys.
* Shared key index values:
* 0) BSS0 key0
* 1) BSS0 key1
* ...
* 4) BSS1 key0
* ...
* 8) BSS2 key0
* ...
* Both pairwise as shared key indeces are determined by
* driver. This is required because the hardware requires
* keys to be assigned in correct order (When key 1 is
* provided but key 0 is not, then the key is not found
* by the hardware during RX).
*/
if (cmd == SET_KEY)
key->hw_key_idx = 0;
if (key->flags & IEEE80211_KEY_FLAG_PAIRWISE)
set_key = rt2x00dev->ops->lib->config_pairwise_key;
else
set_key = rt2x00dev->ops->lib->config_shared_key;
if (!set_key)
return -EOPNOTSUPP;
return set_key(rt2x00dev, &crypto, key);
}
EXPORT_SYMBOL_GPL(rt2x00mac_set_key);
#endif /* CONFIG_RT2X00_LIB_CRYPTO */
void rt2x00mac_sw_scan_start(struct ieee80211_hw *hw)
{
struct rt2x00_dev *rt2x00dev = hw->priv;
__set_bit(DEVICE_STATE_SCANNING, &rt2x00dev->flags);
rt2x00link_stop_tuner(rt2x00dev);
}
EXPORT_SYMBOL_GPL(rt2x00mac_sw_scan_start);
void rt2x00mac_sw_scan_complete(struct ieee80211_hw *hw)
{
struct rt2x00_dev *rt2x00dev = hw->priv;
__clear_bit(DEVICE_STATE_SCANNING, &rt2x00dev->flags);
rt2x00link_start_tuner(rt2x00dev);
}
EXPORT_SYMBOL_GPL(rt2x00mac_sw_scan_complete);
int rt2x00mac_get_stats(struct ieee80211_hw *hw,
struct ieee80211_low_level_stats *stats)
{
struct rt2x00_dev *rt2x00dev = hw->priv;
/*
* The dot11ACKFailureCount, dot11RTSFailureCount and
* dot11RTSSuccessCount are updated in interrupt time.
* dot11FCSErrorCount is updated in the link tuner.
*/
memcpy(stats, &rt2x00dev->low_level_stats, sizeof(*stats));
return 0;
}
EXPORT_SYMBOL_GPL(rt2x00mac_get_stats);
void rt2x00mac_bss_info_changed(struct ieee80211_hw *hw,
struct ieee80211_vif *vif,
struct ieee80211_bss_conf *bss_conf,
u32 changes)
{
struct rt2x00_dev *rt2x00dev = hw->priv;
struct rt2x00_intf *intf = vif_to_intf(vif);
/*
* mac80211 might be calling this function while we are trying
* to remove the device or perhaps suspending it.
*/
if (!test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
return;
/*
* Update the BSSID.
*/
if (changes & BSS_CHANGED_BSSID)
rt2x00lib_config_intf(rt2x00dev, intf, vif->type, NULL,
bss_conf->bssid);
/*
* Update the beacon.
*/
if (changes & (BSS_CHANGED_BEACON | BSS_CHANGED_BEACON_ENABLED))
rt2x00queue_update_beacon(rt2x00dev, vif,
bss_conf->enable_beacon);
/*
* When the association status has changed we must reset the link
* tuner counter. This is because some drivers determine if they
* should perform link tuning based on the number of seconds
* while associated or not associated.
*/
if (changes & BSS_CHANGED_ASSOC) {
rt2x00dev->link.count = 0;
if (bss_conf->assoc)
rt2x00dev->intf_associated++;
else
rt2x00dev->intf_associated--;
rt2x00leds_led_assoc(rt2x00dev, !!rt2x00dev->intf_associated);
}
/*
* When the erp information has changed, we should perform
* additional configuration steps. For all other changes we are done.
*/
if (changes & (BSS_CHANGED_ERP_CTS_PROT | BSS_CHANGED_ERP_PREAMBLE |
BSS_CHANGED_ERP_SLOT | BSS_CHANGED_BASIC_RATES |
BSS_CHANGED_BEACON_INT | BSS_CHANGED_HT))
rt2x00lib_config_erp(rt2x00dev, intf, bss_conf, changes);
}
EXPORT_SYMBOL_GPL(rt2x00mac_bss_info_changed);
int rt2x00mac_conf_tx(struct ieee80211_hw *hw, u16 queue_idx,
const struct ieee80211_tx_queue_params *params)
{
struct rt2x00_dev *rt2x00dev = hw->priv;
struct data_queue *queue;
queue = rt2x00queue_get_queue(rt2x00dev, queue_idx);
if (unlikely(!queue))
return -EINVAL;
/*
* The passed variables are stored as real value ((2^n)-1).
* Ralink registers require to know the bit number 'n'.
*/
if (params->cw_min > 0)
queue->cw_min = fls(params->cw_min);
else
queue->cw_min = 5; /* cw_min: 2^5 = 32. */
if (params->cw_max > 0)
queue->cw_max = fls(params->cw_max);
else
queue->cw_max = 10; /* cw_min: 2^10 = 1024. */
queue->aifs = params->aifs;
queue->txop = params->txop;
INFO(rt2x00dev,
"Configured TX queue %d - CWmin: %d, CWmax: %d, Aifs: %d, TXop: %d.\n",
queue_idx, queue->cw_min, queue->cw_max, queue->aifs, queue->txop);
return 0;
}
EXPORT_SYMBOL_GPL(rt2x00mac_conf_tx);
void rt2x00mac_rfkill_poll(struct ieee80211_hw *hw)
{
struct rt2x00_dev *rt2x00dev = hw->priv;
bool active = !!rt2x00dev->ops->lib->rfkill_poll(rt2x00dev);
wiphy_rfkill_set_hw_state(hw->wiphy, !active);
}
EXPORT_SYMBOL_GPL(rt2x00mac_rfkill_poll);
void rt2x00mac_flush(struct ieee80211_hw *hw, bool drop)
{
struct rt2x00_dev *rt2x00dev = hw->priv;
struct data_queue *queue;
tx_queue_for_each(rt2x00dev, queue)
rt2x00queue_flush_queue(queue, drop);
}
EXPORT_SYMBOL_GPL(rt2x00mac_flush);