ath10k: fix hw roc expiration

It is not guaranteed firmware will switch to
foreign channel immediately after starting scan
sequence. To account for that don't use duration
parameter for scan time. Instead request insanely
long scan and use timeout worker to cancel it from
driver.

This should improve P2P reliability a bit.
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/ath10k/mac.c

@@ -5395,6 +5395,7 @@ static int ath10k_remain_on_channel(struct ieee80211_hw *hw,
 	struct ath10k_vif *arvif = ath10k_vif_to_arvif(vif);
 	struct wmi_start_scan_arg arg;
 	int ret = 0;
+	u32 scan_time_msec;
 
 	mutex_lock(&ar->conf_mutex);
 
@@ -5421,7 +5422,7 @@ static int ath10k_remain_on_channel(struct ieee80211_hw *hw,
 	if (ret)
 		goto exit;
 
-	duration = max(duration, WMI_SCAN_CHAN_MIN_TIME_MSEC);
+	scan_time_msec = ar->hw->wiphy->max_remain_on_channel_duration * 2;
 
 	memset(&arg, 0, sizeof(arg));
 	ath10k_wmi_start_scan_init(ar, &arg);
@@ -5429,9 +5430,9 @@ static int ath10k_remain_on_channel(struct ieee80211_hw *hw,
 	arg.scan_id = ATH10K_SCAN_ID;
 	arg.n_channels = 1;
 	arg.channels[0] = chan->center_freq;
-	arg.dwell_time_active = duration;
-	arg.dwell_time_passive = duration;
-	arg.max_scan_time = 2 * duration;
+	arg.dwell_time_active = scan_time_msec;
+	arg.dwell_time_passive = scan_time_msec;
+	arg.max_scan_time = scan_time_msec;
 	arg.scan_ctrl_flags |= WMI_SCAN_FLAG_PASSIVE;
 	arg.scan_ctrl_flags |= WMI_SCAN_FILTER_PROBE_REQ;
 
@@ -5456,6 +5457,9 @@ static int ath10k_remain_on_channel(struct ieee80211_hw *hw,
 		goto exit;
 	}
 
+	ieee80211_queue_delayed_work(ar->hw, &ar->scan.timeout,
+				     msecs_to_jiffies(duration));
+
 	ret = 0;
 exit:
 	mutex_unlock(&ar->conf_mutex);