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[PATCH 6/9] wifi: wfx: implement wfx_remain_on_channel()

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In some conditions, the device is able to send/receive frames during scan
operation. So, it is possible to use it implement the "remain on channel"
feature: we just ask for a passive scan (without sending any probe request)
on one channel.

This architecture allows to leverage some interesting features:
  - if the device is AP, the device switches channel just after the next
    beacon and the beacons are stopped during the off-channel interval.
  - if the device is connected, it advertises it is asleep before to
    switch channel (so the AP should stop to try to send data)

Signed-off-by: Jérôme Pouiller <jerome.pouiller@xxxxxxxxxx>
---
 drivers/net/wireless/silabs/wfx/scan.c | 50 ++++++++++++++++++++++++++
 drivers/net/wireless/silabs/wfx/scan.h |  1 +
 drivers/net/wireless/silabs/wfx/sta.c  |  1 +
 drivers/net/wireless/silabs/wfx/wfx.h  |  5 ++-
 4 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/silabs/wfx/scan.c b/drivers/net/wireless/silabs/wfx/scan.c
index 51338fd43ae4f..57a2d63dd2a62 100644
--- a/drivers/net/wireless/silabs/wfx/scan.c
+++ b/drivers/net/wireless/silabs/wfx/scan.c
@@ -146,14 +146,64 @@ void wfx_scan_complete(struct wfx_vif *wvif, int nb_chan_done)
 	complete(&wvif->scan_complete);
 }
 
+void wfx_remain_on_channel_work(struct work_struct *work)
+{
+	struct wfx_vif *wvif = container_of(work, struct wfx_vif, remain_on_channel_work);
+	struct ieee80211_channel *chan = wvif->remain_on_channel_chan;
+	int duration = wvif->remain_on_channel_duration;
+	int ret;
+
+	/* Hijack scan request to implement Remain-On-Channel */
+	mutex_lock(&wvif->wdev->conf_mutex);
+	mutex_lock(&wvif->scan_lock);
+	if (wvif->join_in_progress) {
+		dev_info(wvif->wdev->dev, "abort in-progress REQ_JOIN");
+		wfx_reset(wvif);
+	}
+	wfx_tx_lock_flush(wvif->wdev);
+
+	reinit_completion(&wvif->scan_complete);
+	ret = wfx_hif_scan_uniq(wvif, chan, duration);
+	if (ret)
+		goto end;
+	ieee80211_ready_on_channel(wvif->wdev->hw);
+	ret = wait_for_completion_timeout(&wvif->scan_complete,
+					  msecs_to_jiffies(duration * 120 / 100));
+	if (!ret) {
+		wfx_hif_stop_scan(wvif);
+		ret = wait_for_completion_timeout(&wvif->scan_complete, 1 * HZ);
+		dev_dbg(wvif->wdev->dev, "roc timeout\n");
+	}
+	if (!ret)
+		dev_err(wvif->wdev->dev, "roc didn't stop\n");
+	ieee80211_remain_on_channel_expired(wvif->wdev->hw);
+end:
+	wfx_tx_unlock(wvif->wdev);
+	mutex_unlock(&wvif->scan_lock);
+	mutex_unlock(&wvif->wdev->conf_mutex);
+}
+
 int wfx_remain_on_channel(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 			  struct ieee80211_channel *chan, int duration,
 			  enum ieee80211_roc_type type)
 {
+	struct wfx_dev *wdev = hw->priv;
+	struct wfx_vif *wvif = (struct wfx_vif *)vif->drv_priv;
+
+	if (wfx_api_older_than(wdev, 3, 10))
+		return -EOPNOTSUPP;
+
+	wvif->remain_on_channel_duration = duration;
+	wvif->remain_on_channel_chan = chan;
+	schedule_work(&wvif->remain_on_channel_work);
 	return 0;
 }
 
 int wfx_cancel_remain_on_channel(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
 {
+	struct wfx_vif *wvif = (struct wfx_vif *)vif->drv_priv;
+
+	wfx_hif_stop_scan(wvif);
+	flush_work(&wvif->remain_on_channel_work);
 	return 0;
 }
diff --git a/drivers/net/wireless/silabs/wfx/scan.h b/drivers/net/wireless/silabs/wfx/scan.h
index 2f8361769303e..995ab8c6cb5ef 100644
--- a/drivers/net/wireless/silabs/wfx/scan.h
+++ b/drivers/net/wireless/silabs/wfx/scan.h
@@ -19,6 +19,7 @@ int wfx_hw_scan(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 void wfx_cancel_hw_scan(struct ieee80211_hw *hw, struct ieee80211_vif *vif);
 void wfx_scan_complete(struct wfx_vif *wvif, int nb_chan_done);
 
+void wfx_remain_on_channel_work(struct work_struct *work);
 int wfx_remain_on_channel(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 			  struct ieee80211_channel *chan, int duration,
 			  enum ieee80211_roc_type type);
diff --git a/drivers/net/wireless/silabs/wfx/sta.c b/drivers/net/wireless/silabs/wfx/sta.c
index c58db2bcea87b..f42341c2baffb 100644
--- a/drivers/net/wireless/silabs/wfx/sta.c
+++ b/drivers/net/wireless/silabs/wfx/sta.c
@@ -733,6 +733,7 @@ int wfx_add_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
 	mutex_init(&wvif->scan_lock);
 	init_completion(&wvif->scan_complete);
 	INIT_WORK(&wvif->scan_work, wfx_hw_scan_work);
+	INIT_WORK(&wvif->remain_on_channel_work, wfx_remain_on_channel_work);
 
 	wfx_tx_queues_init(wvif);
 	wfx_tx_policy_init(wvif);
diff --git a/drivers/net/wireless/silabs/wfx/wfx.h b/drivers/net/wireless/silabs/wfx/wfx.h
index 13ba84b3b2c33..5fd80c423d6f6 100644
--- a/drivers/net/wireless/silabs/wfx/wfx.h
+++ b/drivers/net/wireless/silabs/wfx/wfx.h
@@ -69,6 +69,7 @@ struct wfx_vif {
 
 	bool                       after_dtim_tx_allowed;
 	bool                       join_in_progress;
+	struct completion          set_pm_mode_complete;
 
 	struct delayed_work        beacon_loss_work;
 
@@ -88,7 +89,9 @@ struct wfx_vif {
 	bool                       scan_abort;
 	struct ieee80211_scan_request *scan_req;
 
-	struct completion          set_pm_mode_complete;
+	struct ieee80211_channel   *remain_on_channel_chan;
+	int                        remain_on_channel_duration;
+	struct work_struct         remain_on_channel_work;
 };
 
 static inline struct ieee80211_vif *wvif_to_vif(struct wfx_vif *wvif)
-- 
2.39.2





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