iwlagn: split remain-on-channel

If we're associated and want to do P2P at the same
time, the scan for remain-on-channel is currently
limited to 80ms because of the way the device will
behave in that case. Instead of doing that, split
up the dwell times into little pieces. It will not
actually be a single big dwell time then, but will
be close enough. This improves robustness of P2P
in such scenarios.

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>

1 files changed, 60 insertions, 39 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-scan.c b/drivers/net/wireless/iwlwifi/iwl-scan.c
index 8ac6b05c6c78..8386a86e2ca2 100644
--- a/drivers/net/wireless/iwlwifi/iwl-scan.c
+++ b/drivers/net/wireless/iwlwifi/iwl-scan.c
@@ -218,8 +218,11 @@ static void iwl_rx_scan_start_notif(struct iwl_priv *priv,
 		       le32_to_cpu(notif->tsf_low),
 		       notif->status, notif->beacon_timer);
 
-	if (priv->scan_type == IWL_SCAN_ROC)
+	if (priv->scan_type == IWL_SCAN_ROC &&
+	    !priv->hw_roc_start_notified) {
 		ieee80211_ready_on_channel(priv->hw);
+		priv->hw_roc_start_notified = true;
+	}
 }
 
 /* Service SCAN_RESULTS_NOTIFICATION (0x83) */
@@ -310,34 +313,38 @@ static u16 iwl_get_active_dwell_time(struct iwl_priv *priv,
 			IWL_ACTIVE_DWELL_FACTOR_24GHZ * (n_probes + 1);
 }
 
+static u16 iwl_limit_dwell(struct iwl_priv *priv, u16 dwell_time)
+{
+	struct iwl_rxon_context *ctx;
+
+	/*
+	 * If we're associated, we clamp the dwell time 98%
+	 * of the smallest beacon interval (minus 2 * channel
+	 * tune time)
+	 */
+	for_each_context(priv, ctx) {
+		u16 value;
+
+		if (!iwl_is_associated_ctx(ctx))
+			continue;
+		value = ctx->beacon_int;
+		if (!value)
+			value = IWL_PASSIVE_DWELL_BASE;
+		value = (value * 98) / 100 - IWL_CHANNEL_TUNE_TIME * 2;
+		dwell_time = min(value, dwell_time);
+	}
+
+	return dwell_time;
+}
+
 static u16 iwl_get_passive_dwell_time(struct iwl_priv *priv,
 				      enum ieee80211_band band)
 {
-	struct iwl_rxon_context *ctx;
 	u16 passive = (band == IEEE80211_BAND_2GHZ) ?
 	    IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_24 :
 	    IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_52;
 
-	if (iwl_is_any_associated(priv)) {
-		/*
-		 * If we're associated, we clamp the maximum passive
-		 * dwell time to be 98% of the smallest beacon interval
-		 * (minus 2 * channel tune time)
-		 */
-		for_each_context(priv, ctx) {
-			u16 value;
-
-			if (!iwl_is_associated_ctx(ctx))
-				continue;
-			value = ctx->vif ? ctx->vif->bss_conf.beacon_int : 0;
-			if ((value > IWL_PASSIVE_DWELL_BASE) || !value)
-				value = IWL_PASSIVE_DWELL_BASE;
-			value = (value * 98) / 100 - IWL_CHANNEL_TUNE_TIME * 2;
-			passive = min(value, passive);
-		}
-	}
-
-	return passive;
+	return iwl_limit_dwell(priv, passive);
 }
 
 static int iwl_get_single_channel_for_scan(struct iwl_priv *priv,
@@ -716,29 +723,43 @@ static int iwlagn_request_scan(struct iwl_priv *priv, struct ieee80211_vif *vif)
 		break;
 	case IWL_SCAN_ROC: {
 		struct iwl_scan_channel *scan_ch;
+		int n_chan, i;
+		u16 dwell;
+
+		dwell = iwl_limit_dwell(priv, priv->hw_roc_duration);
+		n_chan = DIV_ROUND_UP(priv->hw_roc_duration, dwell);
 
-		scan->channel_count = 1;
+		scan->channel_count = n_chan;
 
 		scan_ch = (void *)&scan->data[cmd_len];
-		scan_ch->type = SCAN_CHANNEL_TYPE_PASSIVE;
-		scan_ch->channel =
-			cpu_to_le16(priv->hw_roc_channel->hw_value);
-		scan_ch->active_dwell =
-		scan_ch->passive_dwell =
-			cpu_to_le16(priv->hw_roc_duration);
 
-		/* Set txpower levels to defaults */
-		scan_ch->dsp_atten = 110;
+		for (i = 0; i < n_chan; i++) {
+			scan_ch->type = SCAN_CHANNEL_TYPE_PASSIVE;
+			scan_ch->channel =
+				cpu_to_le16(priv->hw_roc_channel->hw_value);
 
-		/* 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->hw_roc_channel->band == IEEE80211_BAND_5GHZ)
-			scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
-		else
-			scan_ch->tx_gain = ((1 << 5) | (5 << 3));
+			if (i == n_chan - 1)
+				dwell = priv->hw_roc_duration - i * dwell;
+
+			scan_ch->active_dwell =
+			scan_ch->passive_dwell = cpu_to_le16(dwell);
+
+			/* 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->hw_roc_channel->band == IEEE80211_BAND_5GHZ)
+				scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
+			else
+				scan_ch->tx_gain = ((1 << 5) | (5 << 3));
+
+			scan_ch++;
 		}
+		}
+
 		break;
 	}