cw1200: do not allow suspend when it is useless.

Do not allow entering suspend state if firmware is polling
for multicasts and when scanning.

+ bugfix: remove blocking calls from wow_suspend() callback
to reduce suspend time and make sure watchdog is not triggered.

Change-Id: I69196fda25b56d01b90311582705ba586759ae35
Signed-off-by: Dmitry Tarnyagin <dmitry.tarnyagin@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/29079
Reviewed-by: Bartosz MARKOWSKI <bartosz.markowski@tieto.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/33511
Reviewed-by: Philippe LANGLAIS <philippe.langlais@stericsson.com>

3 files changed, 54 insertions, 15 deletions

diff --git a/drivers/staging/cw1200/ap.c b/drivers/staging/cw1200/ap.c
index 39c11172544..e4bf98d46ed 100755
--- a/drivers/staging/cw1200/ap.c
+++ b/drivers/staging/cw1200/ap.c
@@ -539,6 +539,13 @@ void cw1200_suspend_resume(struct cw1200_common *priv,
 		if (arg->stop) {
 			priv->tx_multicast = false;
 		} else {
+			/* Firmware sends this indication every DTIM if there
+			 * is a STA in powersave connected. There is no reason
+			 * to suspend, following wakeup will consume much more
+			 * power than could be saved. */
+			cw1200_pm_stay_awake(&priv->pm_state,
+					priv->join_dtim_period *
+					(priv->beacon_int + 20) * HZ / 1024);
 			priv->tx_multicast = priv->aid0_bit_set &&
 					priv->buffered_multicasts;
 			if (priv->tx_multicast)
@@ -652,6 +659,7 @@ static int cw1200_start_ap(struct cw1200_common *priv)
 		.ssidLength = priv->ssid_length,
 	};
 	priv->beacon_int = conf->beacon_int;
+	priv->join_dtim_period = conf->dtim_period;
 
 	memcpy(&start.ssid[0], priv->ssid, start.ssidLength);
 
diff --git a/drivers/staging/cw1200/pm.c b/drivers/staging/cw1200/pm.c
index e27c4144f51..1d9207c8761 100644
--- a/drivers/staging/cw1200/pm.c
+++ b/drivers/staging/cw1200/pm.c
@@ -23,6 +23,7 @@ struct cw1200_suspend_state {
 	unsigned long bss_loss_tmo;
 	unsigned long connection_loss_tmo;
 	unsigned long join_tmo;
+	unsigned long direct_probe;
 };
 
 static struct dev_pm_ops cw1200_pm_ops = {
@@ -165,24 +166,45 @@ int cw1200_wow_suspend(struct ieee80211_hw *hw, struct cfg80211_wowlan *wowlan)
 		return -EAGAIN;
 #endif
 
-	/* Ensure pending operations are done. */
-	ret = wait_event_interruptible_timeout(
-		priv->channel_switch_done,
-		!priv->channel_switch_in_progress, 3 * HZ);
-	if (WARN_ON(!ret))
-		return -ETIMEDOUT;
-	else if (WARN_ON(ret < 0))
-		return ret;
+	/* Make sure there is no configuration requests in progress. */
+	if (!mutex_trylock(&priv->conf_mutex))
+		return -EBUSY;
+
+	/* Ensure pending operations are done.
+	 * Note also that wow_suspend must return in ~2.5sec, before
+	 * watchdog is triggered. */
+	if (priv->channel_switch_in_progress) {
+		mutex_unlock(&priv->conf_mutex);
+		return -EBUSY;
+	}
+
+	/* Do not suspend when join work is scheduled */
+	if (work_pending(&priv->join_work)) {
+		mutex_unlock(&priv->conf_mutex);
+		return -EBUSY;
+	}
+
+	/* Do not suspend when scanning */
+	if (down_trylock(&priv->scan.lock)) {
+		mutex_unlock(&priv->conf_mutex);
+		return -EBUSY;
+	}
 
-	/* Flush and lock TX. */
-	ret = __cw1200_flush(priv, false);
-	if (WARN_ON(ret < 0))
-		return ret;
+	/* Lock TX. */
+	wsm_lock_tx_async(priv);
+	if (priv->hw_bufs_used) {
+		wsm_unlock_tx(priv);
+		up(&priv->scan.lock);
+		mutex_unlock(&priv->conf_mutex);
+		return -EBUSY;
+	}
 
 	/* Allocate state */
 	state = kzalloc(sizeof(struct cw1200_suspend_state), GFP_KERNEL);
 	if (!state) {
 		wsm_unlock_tx(priv);
+		up(&priv->scan.lock);
+		mutex_unlock(&priv->conf_mutex);
 		return -ENOMEM;
 	}
 
@@ -193,9 +215,8 @@ int cw1200_wow_suspend(struct ieee80211_hw *hw, struct cfg80211_wowlan *wowlan)
 		cw1200_suspend_work(&priv->connection_loss_work);
 	state->join_tmo =
 		cw1200_suspend_work(&priv->join_timeout);
-
-	/* Flush workqueue */
-	flush_workqueue(priv->workqueue);
+	state->direct_probe =
+		cw1200_suspend_work(&priv->scan.probe_work);
 
 	/* Stop serving thread */
 	cw1200_bh_suspend(priv);
@@ -244,10 +265,18 @@ int cw1200_wow_resume(struct ieee80211_hw *hw)
 			state->connection_loss_tmo);
 	cw1200_resume_work(priv, &priv->join_timeout,
 			state->join_tmo);
+	cw1200_resume_work(priv, &priv->scan.probe_work,
+			state->direct_probe);
 
 	/* Unlock datapath */
 	wsm_unlock_tx(priv);
 
+	/* Unlock scan */
+	up(&priv->scan.lock);
+
+	/* Unlock configuration mutex */
+	mutex_unlock(&priv->conf_mutex);
+
 	/* Free memory */
 	kfree(state);
 
diff --git a/drivers/staging/cw1200/scan.c b/drivers/staging/cw1200/scan.c
index c663f6dc173..4daf4e2daa2 100644
--- a/drivers/staging/cw1200/scan.c
+++ b/drivers/staging/cw1200/scan.c
@@ -13,6 +13,7 @@
 #include "cw1200.h"
 #include "scan.h"
 #include "sta.h"
+#include "pm.h"
 
 static void cw1200_scan_restart_delayed(struct cw1200_common *priv);
 
@@ -25,6 +26,7 @@ static int cw1200_scan_start(struct cw1200_common *priv, struct wsm_scan *scan)
 		tmo += scan->ch[i].maxChannelTime + 10;
 
 	atomic_set(&priv->scan.in_progress, 1);
+	cw1200_pm_stay_awake(&priv->pm_state, tmo * HZ / 1000);
 	queue_delayed_work(priv->workqueue, &priv->scan.timeout,
 		tmo * HZ / 1000);
 	ret = wsm_scan(priv, scan);