iwlagn: support off-channel TX

Add support to iwlagn for off-channel TX. The
microcode API for this is a bit strange in that
it uses a hacked-up scan command, so the scan
code needs to change quite a bit to accomodate
that and be able to send it out.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-agn-lib.c

@@ -1115,6 +1115,18 @@ static int iwl_get_channels_for_scan(struct iwl_priv *priv,
 	return added;
 }
 
+static int iwl_fill_offch_tx(struct iwl_priv *priv, void *data, size_t maxlen)
+{
+	struct sk_buff *skb = priv->_agn.offchan_tx_skb;
+
+	if (skb->len < maxlen)
+		maxlen = skb->len;
+
+	memcpy(data, skb->data, maxlen);
+
+	return maxlen;
+}
+
 int iwlagn_request_scan(struct iwl_priv *priv, struct ieee80211_vif *vif)
 {
 	struct iwl_host_cmd cmd = {
@@ -1157,17 +1169,25 @@ int iwlagn_request_scan(struct iwl_priv *priv, struct ieee80211_vif *vif)
 	scan->quiet_plcp_th = IWL_PLCP_QUIET_THRESH;
 	scan->quiet_time = IWL_ACTIVE_QUIET_TIME;
 
-	if (iwl_is_any_associated(priv)) {
+	if (priv->scan_type != IWL_SCAN_OFFCH_TX &&
+	    iwl_is_any_associated(priv)) {
 		u16 interval = 0;
 		u32 extra;
 		u32 suspend_time = 100;
 		u32 scan_suspend_time = 100;
 
 		IWL_DEBUG_INFO(priv, "Scanning while associated...\n");
-		if (priv->is_internal_short_scan)
+		switch (priv->scan_type) {
+		case IWL_SCAN_OFFCH_TX:
+			WARN_ON(1);
+			break;
+		case IWL_SCAN_RADIO_RESET:
 			interval = 0;
-		else
+			break;
+		case IWL_SCAN_NORMAL:
 			interval = vif->bss_conf.beacon_int;
+			break;
+		}
 
 		scan->suspend_time = 0;
 		scan->max_out_time = cpu_to_le32(200 * 1024);
@@ -1180,29 +1200,41 @@ int iwlagn_request_scan(struct iwl_priv *priv, struct ieee80211_vif *vif)
 		scan->suspend_time = cpu_to_le32(scan_suspend_time);
 		IWL_DEBUG_SCAN(priv, "suspend_time 0x%X beacon interval %d\n",
 			       scan_suspend_time, interval);
+	} else if (priv->scan_type == IWL_SCAN_OFFCH_TX) {
+		scan->suspend_time = 0;
+		scan->max_out_time =
+			cpu_to_le32(1024 * priv->_agn.offchan_tx_timeout);
 	}
 
-	if (priv->is_internal_short_scan) {
+	switch (priv->scan_type) {
+	case IWL_SCAN_RADIO_RESET:
 		IWL_DEBUG_SCAN(priv, "Start internal passive scan.\n");
-	} else if (priv->scan_request->n_ssids) {
-		int i, p = 0;
-		IWL_DEBUG_SCAN(priv, "Kicking off active scan\n");
-		for (i = 0; i < priv->scan_request->n_ssids; i++) {
-			/* always does wildcard anyway */
-			if (!priv->scan_request->ssids[i].ssid_len)
-				continue;
-			scan->direct_scan[p].id = WLAN_EID_SSID;
-			scan->direct_scan[p].len =
-				priv->scan_request->ssids[i].ssid_len;
-			memcpy(scan->direct_scan[p].ssid,
-			       priv->scan_request->ssids[i].ssid,
-			       priv->scan_request->ssids[i].ssid_len);
-			n_probes++;
-			p++;
-		}
-		is_active = true;
-	} else
-		IWL_DEBUG_SCAN(priv, "Start passive scan.\n");
+		break;
+	case IWL_SCAN_NORMAL:
+		if (priv->scan_request->n_ssids) {
+			int i, p = 0;
+			IWL_DEBUG_SCAN(priv, "Kicking off active scan\n");
+			for (i = 0; i < priv->scan_request->n_ssids; i++) {
+				/* always does wildcard anyway */
+				if (!priv->scan_request->ssids[i].ssid_len)
+					continue;
+				scan->direct_scan[p].id = WLAN_EID_SSID;
+				scan->direct_scan[p].len =
+					priv->scan_request->ssids[i].ssid_len;
+				memcpy(scan->direct_scan[p].ssid,
+				       priv->scan_request->ssids[i].ssid,
+				       priv->scan_request->ssids[i].ssid_len);
+				n_probes++;
+				p++;
+			}
+			is_active = true;
+		} else
+			IWL_DEBUG_SCAN(priv, "Start passive scan.\n");
+		break;
+	case IWL_SCAN_OFFCH_TX:
+		IWL_DEBUG_SCAN(priv, "Start offchannel TX scan.\n");
+		break;
+	}
 
 	scan->tx_cmd.tx_flags = TX_CMD_FLG_SEQ_CTL_MSK;
 	scan->tx_cmd.sta_id = ctx->bcast_sta_id;
@@ -1300,38 +1332,77 @@ int iwlagn_request_scan(struct iwl_priv *priv, struct ieee80211_vif *vif)
 	rx_chain |= rx_ant << RXON_RX_CHAIN_FORCE_SEL_POS;
 	rx_chain |= 0x1 << RXON_RX_CHAIN_DRIVER_FORCE_POS;
 	scan->rx_chain = cpu_to_le16(rx_chain);
-	if (!priv->is_internal_short_scan) {
+	switch (priv->scan_type) {
+	case IWL_SCAN_NORMAL:
 		cmd_len = iwl_fill_probe_req(priv,
 					(struct ieee80211_mgmt *)scan->data,
 					vif->addr,
 					priv->scan_request->ie,
 					priv->scan_request->ie_len,
 					IWL_MAX_SCAN_SIZE - sizeof(*scan));
-	} else {
+		break;
+	case IWL_SCAN_RADIO_RESET:
 		/* use bcast addr, will not be transmitted but must be valid */
 		cmd_len = iwl_fill_probe_req(priv,
 					(struct ieee80211_mgmt *)scan->data,
 					iwl_bcast_addr, NULL, 0,
 					IWL_MAX_SCAN_SIZE - sizeof(*scan));
-
+		break;
+	case IWL_SCAN_OFFCH_TX:
+		cmd_len = iwl_fill_offch_tx(priv, scan->data,
+					    IWL_MAX_SCAN_SIZE
+					     - sizeof(*scan)
+					     - sizeof(struct iwl_scan_channel));
+		scan->scan_flags |= IWL_SCAN_FLAGS_ACTION_FRAME_TX;
+		break;
+	default:
+		BUG();
 	}
 	scan->tx_cmd.len = cpu_to_le16(cmd_len);
 
 	scan->filter_flags |= (RXON_FILTER_ACCEPT_GRP_MSK |
 			       RXON_FILTER_BCON_AWARE_MSK);
 
-	if (priv->is_internal_short_scan) {
+	switch (priv->scan_type) {
+	case IWL_SCAN_RADIO_RESET:
 		scan->channel_count =
 			iwl_get_single_channel_for_scan(priv, vif, band,
-				(void *)&scan->data[le16_to_cpu(
-				scan->tx_cmd.len)]);
-	} else {
+				(void *)&scan->data[cmd_len]);
+		break;
+	case IWL_SCAN_NORMAL:
 		scan->channel_count =
 			iwl_get_channels_for_scan(priv, vif, band,
 				is_active, n_probes,
-				(void *)&scan->data[le16_to_cpu(
-				scan->tx_cmd.len)]);
+				(void *)&scan->data[cmd_len]);
+		break;
+	case IWL_SCAN_OFFCH_TX: {
+		struct iwl_scan_channel *scan_ch;
+
+		scan->channel_count = 1;
+
+		scan_ch = (void *)&scan->data[cmd_len];
+		scan_ch->type = SCAN_CHANNEL_TYPE_ACTIVE;
+		scan_ch->channel =
+			cpu_to_le16(priv->_agn.offchan_tx_chan->hw_value);
+		scan_ch->active_dwell =
+			cpu_to_le16(priv->_agn.offchan_tx_timeout);
+		scan_ch->passive_dwell = 0;
+
+		/* Set txpower levels to defaults */
+		scan_ch->dsp_atten = 110;
+
+		/* NOTE: if we were doing 6Mb OFDM for scans we'd use
+		 * power level:
+		 * scan_ch->tx_gain = ((1 << 5) | (2 << 3)) | 3;
+		 */
+		if (priv->_agn.offchan_tx_chan->band == IEEE80211_BAND_5GHZ)
+			scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
+		else
+			scan_ch->tx_gain = ((1 << 5) | (5 << 3));
+		}
+		break;
 	}
+
 	if (scan->channel_count == 0) {
 		IWL_DEBUG_SCAN(priv, "channel count %d\n", scan->channel_count);
 		return -EIO;

drivers/net/wireless/iwlwifi/iwl-agn.c

@@ -2937,6 +2937,91 @@ static void iwl_bg_rx_replenish(struct work_struct *data)
 	mutex_unlock(&priv->mutex);
 }
 
+static int iwl_mac_offchannel_tx(struct ieee80211_hw *hw, struct sk_buff *skb,
+				 struct ieee80211_channel *chan,
+				 enum nl80211_channel_type channel_type,
+				 unsigned int wait)
+{
+	struct iwl_priv *priv = hw->priv;
+	int ret;
+
+	/* Not supported if we don't have PAN */
+	if (!(priv->valid_contexts & BIT(IWL_RXON_CTX_PAN))) {
+		ret = -EOPNOTSUPP;
+		goto free;
+	}
+
+	/* Not supported on pre-P2P firmware */
+	if (!(priv->contexts[IWL_RXON_CTX_PAN].interface_modes &
+					BIT(NL80211_IFTYPE_P2P_CLIENT))) {
+		ret = -EOPNOTSUPP;
+		goto free;
+	}
+
+	mutex_lock(&priv->mutex);
+
+	if (!priv->contexts[IWL_RXON_CTX_PAN].is_active) {
+		/*
+		 * If the PAN context is free, use the normal
+		 * way of doing remain-on-channel offload + TX.
+		 */
+		ret = 1;
+		goto out;
+	}
+
+	/* TODO: queue up if scanning? */
+	if (test_bit(STATUS_SCANNING, &priv->status) ||
+	    priv->_agn.offchan_tx_skb) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	/*
+	 * max_scan_ie_len doesn't include the blank SSID or the header,
+	 * so need to add that again here.
+	 */
+	if (skb->len > hw->wiphy->max_scan_ie_len + 24 + 2) {
+		ret = -ENOBUFS;
+		goto out;
+	}
+
+	priv->_agn.offchan_tx_skb = skb;
+	priv->_agn.offchan_tx_timeout = wait;
+	priv->_agn.offchan_tx_chan = chan;
+
+	ret = iwl_scan_initiate(priv, priv->contexts[IWL_RXON_CTX_PAN].vif,
+				IWL_SCAN_OFFCH_TX, chan->band);
+	if (ret)
+		priv->_agn.offchan_tx_skb = NULL;
+ out:
+	mutex_unlock(&priv->mutex);
+ free:
+	if (ret < 0)
+		kfree_skb(skb);
+
+	return ret;
+}
+
+static int iwl_mac_offchannel_tx_cancel_wait(struct ieee80211_hw *hw)
+{
+	struct iwl_priv *priv = hw->priv;
+	int ret;
+
+	mutex_lock(&priv->mutex);
+
+	if (!priv->_agn.offchan_tx_skb)
+		return -EINVAL;
+
+	priv->_agn.offchan_tx_skb = NULL;
+
+	ret = iwl_scan_cancel_timeout(priv, 200);
+	if (ret)
+		ret = -EIO;
+	mutex_unlock(&priv->mutex);
+
+	return ret;
+}
+
 /*****************************************************************************
  *
  * mac80211 entry point functions
@@ -3815,6 +3900,8 @@ struct ieee80211_ops iwlagn_hw_ops = {
 	.tx_last_beacon = iwl_mac_tx_last_beacon,
 	.remain_on_channel = iwl_mac_remain_on_channel,
 	.cancel_remain_on_channel = iwl_mac_cancel_remain_on_channel,
+	.offchannel_tx = iwl_mac_offchannel_tx,
+	.offchannel_tx_cancel_wait = iwl_mac_offchannel_tx_cancel_wait,
 };
 
 static void iwl_hw_detect(struct iwl_priv *priv)

drivers/net/wireless/iwlwifi/iwl-commands.h

@@ -2964,9 +2964,15 @@ struct iwl3945_scan_cmd {
 	u8 data[0];
 } __packed;
 
+enum iwl_scan_flags {
+	/* BIT(0) currently unused */
+	IWL_SCAN_FLAGS_ACTION_FRAME_TX	= BIT(1),
+	/* bits 2-7 reserved */
+};
+
 struct iwl_scan_cmd {
 	__le16 len;
-	u8 reserved0;
+	u8 scan_flags;		/* scan flags: see enum iwl_scan_flags */
 	u8 channel_count;	/* # channels in channel list */
 	__le16 quiet_time;	/* dwell only this # millisecs on quiet channel
 				 * (only for active scan) */

drivers/net/wireless/iwlwifi/iwl-core.h

@@ -63,6 +63,8 @@
 #ifndef __iwl_core_h__
 #define __iwl_core_h__
 
+#include "iwl-dev.h"
+
 /************************
  * forward declarations *
  ************************/
@@ -551,6 +553,10 @@ u16 iwl_get_passive_dwell_time(struct iwl_priv *priv,
 			       struct ieee80211_vif *vif);
 void iwl_setup_scan_deferred_work(struct iwl_priv *priv);
 void iwl_cancel_scan_deferred_work(struct iwl_priv *priv);
+int __must_check iwl_scan_initiate(struct iwl_priv *priv,
+				   struct ieee80211_vif *vif,
+				   enum iwl_scan_type scan_type,
+				   enum ieee80211_band band);
 
 /* For faster active scanning, scan will move to the next channel if fewer than
  * PLCP_QUIET_THRESH packets are heard on this channel within

drivers/net/wireless/iwlwifi/iwl-dev.h

@@ -1230,6 +1230,12 @@ struct iwl_rxon_context {
 	} ht;
 };
 
+enum iwl_scan_type {
+	IWL_SCAN_NORMAL,
+	IWL_SCAN_RADIO_RESET,
+	IWL_SCAN_OFFCH_TX,
+};
+
 struct iwl_priv {
 
 	/* ieee device used by generic ieee processing code */
@@ -1290,7 +1296,7 @@ struct iwl_priv {
 	enum ieee80211_band scan_band;
 	struct cfg80211_scan_request *scan_request;
 	struct ieee80211_vif *scan_vif;
-	bool is_internal_short_scan;
+	enum iwl_scan_type scan_type;
 	u8 scan_tx_ant[IEEE80211_NUM_BANDS];
 	u8 mgmt_tx_ant;
 
@@ -1504,6 +1510,10 @@ struct iwl_priv {
 			struct delayed_work hw_roc_work;
 			enum nl80211_channel_type hw_roc_chantype;
 			int hw_roc_duration;
+
+			struct sk_buff *offchan_tx_skb;
+			int offchan_tx_timeout;
+			struct ieee80211_channel *offchan_tx_chan;
 		} _agn;
 #endif
 	};