--- /dev/null
+--- a/drivers/net/wireless/ath/ath9k/main.c
++++ b/drivers/net/wireless/ath/ath9k/main.c
+@@ -1790,6 +1790,7 @@ static void ath9k_bss_info_changed(struc
+ struct ath_hw *ah = sc->sc_ah;
+ struct ath_common *common = ath9k_hw_common(ah);
+ struct ath_vif *avp = (void *)vif->drv_priv;
++ int slottime;
+ int error;
+
+ mutex_lock(&sc->mutex);
+@@ -1825,6 +1826,25 @@ static void ath9k_bss_info_changed(struc
+ ath_beacon_config(sc, vif);
+ }
+
++ if (changed & BSS_CHANGED_ERP_SLOT) {
++ if (bss_conf->use_short_slot)
++ slottime = 9;
++ else
++ slottime = 20;
++ if (vif->type == NL80211_IFTYPE_AP) {
++ /*
++ * Defer update, so that connected stations can adjust
++ * their settings at the same time.
++ * See beacon.c for more details
++ */
++ sc->beacon.slottime = slottime;
++ sc->beacon.updateslot = UPDATE;
++ } else {
++ ah->slottime = slottime;
++ ath9k_hw_init_global_settings(ah);
++ }
++ }
++
+ /* Disable transmission of beacons */
+ if ((changed & BSS_CHANGED_BEACON_ENABLED) && !bss_conf->enable_beacon)
+ ath9k_hw_stoptxdma(sc->sc_ah, sc->beacon.beaconq);
+--- a/drivers/net/wireless/ath/ath9k/hw.c
++++ b/drivers/net/wireless/ath/ath9k/hw.c
+@@ -55,28 +55,6 @@ module_exit(ath9k_exit);
+ /* Helper Functions */
+ /********************/
+
+-static u32 ath9k_hw_mac_usec(struct ath_hw *ah, u32 clks)
+-{
+- struct ieee80211_conf *conf = &ath9k_hw_common(ah)->hw->conf;
+-
+- if (!ah->curchan) /* should really check for CCK instead */
+- return clks / ATH9K_CLOCK_RATE_CCK;
+- if (conf->channel->band == IEEE80211_BAND_2GHZ)
+- return clks / ATH9K_CLOCK_RATE_2GHZ_OFDM;
+-
+- return clks / ATH9K_CLOCK_RATE_5GHZ_OFDM;
+-}
+-
+-static u32 ath9k_hw_mac_to_usec(struct ath_hw *ah, u32 clks)
+-{
+- struct ieee80211_conf *conf = &ath9k_hw_common(ah)->hw->conf;
+-
+- if (conf_is_ht40(conf))
+- return ath9k_hw_mac_usec(ah, clks) / 2;
+- else
+- return ath9k_hw_mac_usec(ah, clks);
+-}
+-
+ static u32 ath9k_hw_mac_clks(struct ath_hw *ah, u32 usecs)
+ {
+ struct ieee80211_conf *conf = &ath9k_hw_common(ah)->hw->conf;
+@@ -413,8 +391,6 @@ static void ath9k_hw_init_defaults(struc
+ ah->beacon_interval = 100;
+ ah->enable_32kHz_clock = DONT_USE_32KHZ;
+ ah->slottime = (u32) -1;
+- ah->acktimeout = (u32) -1;
+- ah->ctstimeout = (u32) -1;
+ ah->globaltxtimeout = (u32) -1;
+ ah->power_mode = ATH9K_PM_UNDEFINED;
+ }
+@@ -1196,34 +1172,25 @@ static void ath9k_hw_init_interrupt_mask
+ }
+ }
+
+-static bool ath9k_hw_set_ack_timeout(struct ath_hw *ah, u32 us)
++static void ath9k_hw_setslottime(struct ath_hw *ah, u32 us)
+ {
+- if (us > ath9k_hw_mac_to_usec(ah, MS(0xffffffff, AR_TIME_OUT_ACK))) {
+- ath_print(ath9k_hw_common(ah), ATH_DBG_RESET,
+- "bad ack timeout %u\n", us);
+- ah->acktimeout = (u32) -1;
+- return false;
+- } else {
+- REG_RMW_FIELD(ah, AR_TIME_OUT,
+- AR_TIME_OUT_ACK, ath9k_hw_mac_to_clks(ah, us));
+- ah->acktimeout = us;
+- return true;
+- }
++ u32 val = ath9k_hw_mac_to_clks(ah, us);
++ val = min(val, (u32) 0xFFFF);
++ REG_WRITE(ah, AR_D_GBL_IFS_SLOT, val);
+ }
+
+-static bool ath9k_hw_set_cts_timeout(struct ath_hw *ah, u32 us)
++static void ath9k_hw_set_ack_timeout(struct ath_hw *ah, u32 us)
+ {
+- if (us > ath9k_hw_mac_to_usec(ah, MS(0xffffffff, AR_TIME_OUT_CTS))) {
+- ath_print(ath9k_hw_common(ah), ATH_DBG_RESET,
+- "bad cts timeout %u\n", us);
+- ah->ctstimeout = (u32) -1;
+- return false;
+- } else {
+- REG_RMW_FIELD(ah, AR_TIME_OUT,
+- AR_TIME_OUT_CTS, ath9k_hw_mac_to_clks(ah, us));
+- ah->ctstimeout = us;
+- return true;
+- }
++ u32 val = ath9k_hw_mac_to_clks(ah, us);
++ val = min(val, (u32) MS(0xFFFFFFFF, AR_TIME_OUT_ACK));
++ REG_RMW_FIELD(ah, AR_TIME_OUT, AR_TIME_OUT_ACK, val);
++}
++
++static void ath9k_hw_set_cts_timeout(struct ath_hw *ah, u32 us)
++{
++ u32 val = ath9k_hw_mac_to_clks(ah, us);
++ val = min(val, (u32) MS(0xFFFFFFFF, AR_TIME_OUT_CTS));
++ REG_RMW_FIELD(ah, AR_TIME_OUT, AR_TIME_OUT_CTS, val);
+ }
+
+ static bool ath9k_hw_set_global_txtimeout(struct ath_hw *ah, u32 tu)
+@@ -1240,23 +1207,32 @@ static bool ath9k_hw_set_global_txtimeou
+ }
+ }
+
+-static void ath9k_hw_init_user_settings(struct ath_hw *ah)
++void ath9k_hw_init_global_settings(struct ath_hw *ah)
+ {
++ struct ieee80211_conf *conf = &ath9k_hw_common(ah)->hw->conf;
++ int acktimeout;
++ int sifstime;
++
+ ath_print(ath9k_hw_common(ah), ATH_DBG_RESET, "ah->misc_mode 0x%x\n",
+ ah->misc_mode);
+
+ if (ah->misc_mode != 0)
+ REG_WRITE(ah, AR_PCU_MISC,
+ REG_READ(ah, AR_PCU_MISC) | ah->misc_mode);
+- if (ah->slottime != (u32) -1)
+- ath9k_hw_setslottime(ah, ah->slottime);
+- if (ah->acktimeout != (u32) -1)
+- ath9k_hw_set_ack_timeout(ah, ah->acktimeout);
+- if (ah->ctstimeout != (u32) -1)
+- ath9k_hw_set_cts_timeout(ah, ah->ctstimeout);
++
++ if (conf->channel && conf->channel->band == IEEE80211_BAND_5GHZ)
++ sifstime = 16;
++ else
++ sifstime = 10;
++
++ acktimeout = ah->slottime + sifstime;
++ ath9k_hw_setslottime(ah, ah->slottime);
++ ath9k_hw_set_ack_timeout(ah, acktimeout);
++ ath9k_hw_set_cts_timeout(ah, acktimeout);
+ if (ah->globaltxtimeout != (u32) -1)
+ ath9k_hw_set_global_txtimeout(ah, ah->globaltxtimeout);
+ }
++EXPORT_SYMBOL(ath9k_hw_init_global_settings);
+
+ void ath9k_hw_deinit(struct ath_hw *ah)
+ {
+@@ -2077,7 +2053,7 @@ int ath9k_hw_reset(struct ath_hw *ah, st
+ if (ah->caps.hw_caps & ATH9K_HW_CAP_RFSILENT)
+ ath9k_enable_rfkill(ah);
+
+- ath9k_hw_init_user_settings(ah);
++ ath9k_hw_init_global_settings(ah);
+
+ if (AR_SREV_9287_12_OR_LATER(ah)) {
+ REG_WRITE(ah, AR_D_GBL_IFS_SIFS,
+@@ -3674,21 +3650,6 @@ u64 ath9k_hw_extend_tsf(struct ath_hw *a
+ }
+ EXPORT_SYMBOL(ath9k_hw_extend_tsf);
+
+-bool ath9k_hw_setslottime(struct ath_hw *ah, u32 us)
+-{
+- if (us < ATH9K_SLOT_TIME_9 || us > ath9k_hw_mac_to_usec(ah, 0xffff)) {
+- ath_print(ath9k_hw_common(ah), ATH_DBG_RESET,
+- "bad slot time %u\n", us);
+- ah->slottime = (u32) -1;
+- return false;
+- } else {
+- REG_WRITE(ah, AR_D_GBL_IFS_SLOT, ath9k_hw_mac_to_clks(ah, us));
+- ah->slottime = us;
+- return true;
+- }
+-}
+-EXPORT_SYMBOL(ath9k_hw_setslottime);
+-
+ void ath9k_hw_set11nmac2040(struct ath_hw *ah)
+ {
+ struct ieee80211_conf *conf = &ath9k_hw_common(ah)->hw->conf;
+--- a/drivers/net/wireless/ath/ath9k/hw.h
++++ b/drivers/net/wireless/ath/ath9k/hw.h
+@@ -553,8 +553,6 @@ struct ath_hw {
+ int16_t txpower_indexoffset;
+ u32 beacon_interval;
+ u32 slottime;
+- u32 acktimeout;
+- u32 ctstimeout;
+ u32 globaltxtimeout;
+
+ /* ANI */
+@@ -668,7 +666,7 @@ void ath9k_hw_settsf64(struct ath_hw *ah
+ void ath9k_hw_reset_tsf(struct ath_hw *ah);
+ void ath9k_hw_set_tsfadjust(struct ath_hw *ah, u32 setting);
+ u64 ath9k_hw_extend_tsf(struct ath_hw *ah, u32 rstamp);
+-bool ath9k_hw_setslottime(struct ath_hw *ah, u32 us);
++void ath9k_hw_init_global_settings(struct ath_hw *ah);
+ void ath9k_hw_set11nmac2040(struct ath_hw *ah);
+ void ath9k_hw_beaconinit(struct ath_hw *ah, u32 next_beacon, u32 beacon_period);
+ void ath9k_hw_set_sta_beacon_timers(struct ath_hw *ah,
+--- a/drivers/net/wireless/ath/ath9k/beacon.c
++++ b/drivers/net/wireless/ath/ath9k/beacon.c
+@@ -480,7 +480,8 @@ void ath_beacon_tasklet(unsigned long da
+ sc->beacon.updateslot = COMMIT; /* commit next beacon */
+ sc->beacon.slotupdate = slot;
+ } else if (sc->beacon.updateslot == COMMIT && sc->beacon.slotupdate == slot) {
+- ath9k_hw_setslottime(sc->sc_ah, sc->beacon.slottime);
++ ah->slottime = sc->beacon.slottime;
++ ath9k_hw_init_global_settings(ah);
+ sc->beacon.updateslot = OK;
+ }
+ if (bfaddr != 0) {
--- /dev/null
+--- a/drivers/net/wireless/ath/ath9k/hw.c
++++ b/drivers/net/wireless/ath/ath9k/hw.c
+@@ -1211,6 +1211,7 @@ void ath9k_hw_init_global_settings(struc
+ {
+ struct ieee80211_conf *conf = &ath9k_hw_common(ah)->hw->conf;
+ int acktimeout;
++ int slottime;
+ int sifstime;
+
+ ath_print(ath9k_hw_common(ah), ATH_DBG_RESET, "ah->misc_mode 0x%x\n",
+@@ -1225,8 +1226,10 @@ void ath9k_hw_init_global_settings(struc
+ else
+ sifstime = 10;
+
+- acktimeout = ah->slottime + sifstime;
+- ath9k_hw_setslottime(ah, ah->slottime);
++ /* As defined by IEEE 802.11-2007 17.3.8.6 */
++ slottime = ah->slottime + 3 * ah->coverage_class;
++ acktimeout = slottime + sifstime;
++ ath9k_hw_setslottime(ah, slottime);
+ ath9k_hw_set_ack_timeout(ah, acktimeout);
+ ath9k_hw_set_cts_timeout(ah, acktimeout);
+ if (ah->globaltxtimeout != (u32) -1)
+--- a/drivers/net/wireless/ath/ath9k/hw.h
++++ b/drivers/net/wireless/ath/ath9k/hw.h
+@@ -551,6 +551,7 @@ struct ath_hw {
+ u32 *bank6Temp;
+
+ int16_t txpower_indexoffset;
++ int coverage_class;
+ u32 beacon_interval;
+ u32 slottime;
+ u32 globaltxtimeout;
+--- a/drivers/net/wireless/ath/ath9k/main.c
++++ b/drivers/net/wireless/ath/ath9k/main.c
+@@ -2015,6 +2015,18 @@ static void ath9k_sw_scan_complete(struc
+ mutex_unlock(&sc->mutex);
+ }
+
++static void ath9k_set_coverage_class(struct ieee80211_hw *hw, u8 coverage_class)
++{
++ struct ath_wiphy *aphy = hw->priv;
++ struct ath_softc *sc = aphy->sc;
++ struct ath_hw *ah = sc->sc_ah;
++
++ mutex_lock(&sc->mutex);
++ ah->coverage_class = coverage_class;
++ ath9k_hw_init_global_settings(ah);
++ mutex_unlock(&sc->mutex);
++}
++
+ struct ieee80211_ops ath9k_ops = {
+ .tx = ath9k_tx,
+ .start = ath9k_start,
+@@ -2034,4 +2046,5 @@ struct ieee80211_ops ath9k_ops = {
+ .sw_scan_start = ath9k_sw_scan_start,
+ .sw_scan_complete = ath9k_sw_scan_complete,
+ .rfkill_poll = ath9k_rfkill_poll_state,
++ .set_coverage_class = ath9k_set_coverage_class,
+ };