ath9k: add TX99 support

TX99 support enables Specific Absorption Rate (SAR) testing.
SAR is the unit of measurement for the amount of radio frequency(RF)
absorbed by the body when using a wireless device. The RF
exposure limits used are expressed in the terms of SAR, which is a
measure of the electric and magnetic field strength and power density
for transmitters operating at frequencies from 300 kHz to 100 GHz.

Regulatory bodies around the world require that wireless device
be evaluated to meet the RF exposure limits set forth in the
governmental SAR regulations.

In the examples below, for more bit rate options see the iw TX bitrate
setting documentation:

http://wireless.kernel.org/en/users/Documentation/iw#Modifying_transmit_bitrates

Example usage:

iw phy phy0 interface add moni0 type monitor
ip link set dev moni0 up

iw dev moni0 set channel 36 HT40+
iw set bitrates mcs-5 4

echo 10 > /sys/kernel/debug/ieee80211/phy0/ath9k/tx99_power
echo 1  > /sys/kernel/debug/ieee80211/phy0/ath9k/tx99

Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 159 insertions, 1 deletions

diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index c42b55c1face..98964b02f139 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -1047,6 +1047,14 @@ static int ath9k_add_interface(struct ieee80211_hw *hw,
 
 	mutex_lock(&sc->mutex);
 
+	if (config_enabled(CONFIG_ATH9K_TX99)) {
+		if (sc->nvifs >= 1) {
+			mutex_unlock(&sc->mutex);
+			return -EOPNOTSUPP;
+		}
+		sc->tx99_vif = vif;
+	}
+
 	ath_dbg(common, CONFIG, "Attach a VIF of type: %d\n", vif->type);
 	sc->nvifs++;
 
@@ -1075,9 +1083,15 @@ static int ath9k_change_interface(struct ieee80211_hw *hw,
 	struct ath_softc *sc = hw->priv;
 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
 
-	ath_dbg(common, CONFIG, "Change Interface\n");
 	mutex_lock(&sc->mutex);
 
+	if (config_enabled(CONFIG_ATH9K_TX99)) {
+		mutex_unlock(&sc->mutex);
+		return -EOPNOTSUPP;
+	}
+
+	ath_dbg(common, CONFIG, "Change Interface\n");
+
 	if (ath9k_uses_beacons(vif->type))
 		ath9k_beacon_remove_slot(sc, vif);
 
@@ -1107,6 +1121,7 @@ static void ath9k_remove_interface(struct ieee80211_hw *hw,
 	mutex_lock(&sc->mutex);
 
 	sc->nvifs--;
+	sc->tx99_vif = NULL;
 
 	if (ath9k_uses_beacons(vif->type))
 		ath9k_beacon_remove_slot(sc, vif);
@@ -1128,6 +1143,9 @@ static void ath9k_enable_ps(struct ath_softc *sc)
 	struct ath_hw *ah = sc->sc_ah;
 	struct ath_common *common = ath9k_hw_common(ah);
 
+	if (config_enabled(CONFIG_ATH9K_TX99))
+		return;
+
 	sc->ps_enabled = true;
 	if (!(ah->caps.hw_caps & ATH9K_HW_CAP_AUTOSLEEP)) {
 		if ((ah->imask & ATH9K_INT_TIM_TIMER) == 0) {
@@ -1144,6 +1162,9 @@ static void ath9k_disable_ps(struct ath_softc *sc)
 	struct ath_hw *ah = sc->sc_ah;
 	struct ath_common *common = ath9k_hw_common(ah);
 
+	if (config_enabled(CONFIG_ATH9K_TX99))
+		return;
+
 	sc->ps_enabled = false;
 	ath9k_hw_setpower(ah, ATH9K_PM_AWAKE);
 	if (!(ah->caps.hw_caps & ATH9K_HW_CAP_AUTOSLEEP)) {
@@ -1167,6 +1188,9 @@ void ath9k_spectral_scan_trigger(struct ieee80211_hw *hw)
 	struct ath_common *common = ath9k_hw_common(ah);
 	u32 rxfilter;
 
+	if (config_enabled(CONFIG_ATH9K_TX99))
+		return;
+
 	if (!ath9k_hw_ops(ah)->spectral_scan_trigger) {
 		ath_err(common, "spectrum analyzer not implemented on this hardware\n");
 		return;
@@ -1746,6 +1770,9 @@ static int ath9k_get_survey(struct ieee80211_hw *hw, int idx,
 	unsigned long flags;
 	int pos;
 
+	if (config_enabled(CONFIG_ATH9K_TX99))
+		return -EOPNOTSUPP;
+
 	spin_lock_irqsave(&common->cc_lock, flags);
 	if (idx == 0)
 		ath_update_survey_stats(sc);
@@ -1778,6 +1805,9 @@ static void ath9k_set_coverage_class(struct ieee80211_hw *hw, u8 coverage_class)
 	struct ath_softc *sc = hw->priv;
 	struct ath_hw *ah = sc->sc_ah;
 
+	if (config_enabled(CONFIG_ATH9K_TX99))
+		return;
+
 	mutex_lock(&sc->mutex);
 	ah->coverage_class = coverage_class;
 
@@ -2344,6 +2374,134 @@ static void ath9k_channel_switch_beacon(struct ieee80211_hw *hw,
 	sc->csa_vif = vif;
 }
 
+static void ath9k_tx99_stop(struct ath_softc *sc)
+{
+	struct ath_hw *ah = sc->sc_ah;
+	struct ath_common *common = ath9k_hw_common(ah);
+
+	ath_drain_all_txq(sc);
+	ath_startrecv(sc);
+
+	ath9k_hw_set_interrupts(ah);
+	ath9k_hw_enable_interrupts(ah);
+
+	ieee80211_wake_queues(sc->hw);
+
+	kfree_skb(sc->tx99_skb);
+	sc->tx99_skb = NULL;
+	sc->tx99_state = false;
+
+	ath9k_hw_tx99_stop(sc->sc_ah);
+	ath_dbg(common, XMIT, "TX99 stopped\n");
+}
+
+static struct sk_buff *ath9k_build_tx99_skb(struct ath_softc *sc)
+{
+	static u8 PN9Data[] = {0xff, 0x87, 0xb8, 0x59, 0xb7, 0xa1, 0xcc, 0x24,
+			       0x57, 0x5e, 0x4b, 0x9c, 0x0e, 0xe9, 0xea, 0x50,
+			       0x2a, 0xbe, 0xb4, 0x1b, 0xb6, 0xb0, 0x5d, 0xf1,
+			       0xe6, 0x9a, 0xe3, 0x45, 0xfd, 0x2c, 0x53, 0x18,
+			       0x0c, 0xca, 0xc9, 0xfb, 0x49, 0x37, 0xe5, 0xa8,
+			       0x51, 0x3b, 0x2f, 0x61, 0xaa, 0x72, 0x18, 0x84,
+			       0x02, 0x23, 0x23, 0xab, 0x63, 0x89, 0x51, 0xb3,
+			       0xe7, 0x8b, 0x72, 0x90, 0x4c, 0xe8, 0xfb, 0xc0};
+	u32 len = 1200;
+	struct ieee80211_hw *hw = sc->hw;
+	struct ieee80211_hdr *hdr;
+	struct ieee80211_tx_info *tx_info;
+	struct sk_buff *skb;
+
+	skb = alloc_skb(len, GFP_KERNEL);
+	if (!skb)
+		return NULL;
+
+	skb_put(skb, len);
+
+	memset(skb->data, 0, len);
+
+	hdr = (struct ieee80211_hdr *)skb->data;
+	hdr->frame_control = cpu_to_le16(IEEE80211_FTYPE_DATA);
+	hdr->duration_id = 0;
+
+	memcpy(hdr->addr1, hw->wiphy->perm_addr, ETH_ALEN);
+	memcpy(hdr->addr2, hw->wiphy->perm_addr, ETH_ALEN);
+	memcpy(hdr->addr3, hw->wiphy->perm_addr, ETH_ALEN);
+
+	hdr->seq_ctrl |= cpu_to_le16(sc->tx.seq_no);
+
+	tx_info = IEEE80211_SKB_CB(skb);
+	memset(tx_info, 0, sizeof(*tx_info));
+	tx_info->band = hw->conf.chandef.chan->band;
+	tx_info->flags = IEEE80211_TX_CTL_NO_ACK;
+	tx_info->control.vif = sc->tx99_vif;
+
+	memcpy(skb->data + sizeof(*hdr), PN9Data, sizeof(PN9Data));
+
+	return skb;
+}
+
+void ath9k_tx99_deinit(struct ath_softc *sc)
+{
+	ath_reset(sc);
+
+	ath9k_ps_wakeup(sc);
+	ath9k_tx99_stop(sc);
+	ath9k_ps_restore(sc);
+}
+
+int ath9k_tx99_init(struct ath_softc *sc)
+{
+	struct ieee80211_hw *hw = sc->hw;
+	struct ath_hw *ah = sc->sc_ah;
+	struct ath_common *common = ath9k_hw_common(ah);
+	struct ath_tx_control txctl;
+	int r;
+
+	if (sc->sc_flags & SC_OP_INVALID) {
+		ath_err(common,
+			"driver is in invalid state unable to use TX99");
+		return -EINVAL;
+	}
+
+	sc->tx99_skb = ath9k_build_tx99_skb(sc);
+	if (!sc->tx99_skb)
+		return -ENOMEM;
+
+	memset(&txctl, 0, sizeof(txctl));
+	txctl.txq = sc->tx.txq_map[IEEE80211_AC_VO];
+
+	ath_reset(sc);
+
+	ath9k_ps_wakeup(sc);
+
+	ath9k_hw_disable_interrupts(ah);
+	atomic_set(&ah->intr_ref_cnt, -1);
+	ath_drain_all_txq(sc);
+	ath_stoprecv(sc);
+
+	sc->tx99_state = true;
+
+	ieee80211_stop_queues(hw);
+
+	if (sc->tx99_power == MAX_RATE_POWER + 1)
+		sc->tx99_power = MAX_RATE_POWER;
+
+	ath9k_hw_tx99_set_txpower(ah, sc->tx99_power);
+	r = ath9k_tx99_send(sc, sc->tx99_skb, &txctl);
+	if (r) {
+		ath_dbg(common, XMIT, "Failed to xmit TX99 skb\n");
+		return r;
+	}
+
+	ath_dbg(common, XMIT, "TX99 xmit started using %d ( %ddBm)\n",
+		sc->tx99_power,
+		sc->tx99_power / 2);
+
+	/* We leave the harware awake as it will be chugging on */
+
+	return 0;
+}
+
 struct ieee80211_ops ath9k_ops = {
 	.tx 		    = ath9k_tx,
 	.start 		    = ath9k_start,