wifi: wfx: implement wfx_remain_on_channel()

With 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@silabs.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231004172843.195332-9-jerome.pouiller@silabs.com

diff --git a/drivers/net/wireless/silabs/wfx/main.c b/drivers/net/wireless/silabs/wfx/main.c
index 4bf16bceb0bbc68abb77c239b4c2633e3855a72d..e7198520bdffc7f9754566079cb1a5965c7825de 100644 (file)
--- a/drivers/net/wireless/silabs/wfx/main.c
+++ b/drivers/net/wireless/silabs/wfx/main.c
@@ -151,6 +151,8 @@ static const struct ieee80211_ops wfx_ops = {
        .change_chanctx          = wfx_change_chanctx,
        .assign_vif_chanctx      = wfx_assign_vif_chanctx,
        .unassign_vif_chanctx    = wfx_unassign_vif_chanctx,
+       .remain_on_channel       = wfx_remain_on_channel,
+       .cancel_remain_on_channel = wfx_cancel_remain_on_channel,
 };
 
 bool wfx_api_older_than(struct wfx_dev *wdev, int major, int minor)
@@ -289,6 +291,7 @@ struct wfx_dev *wfx_init_common(struct device *dev, const struct wfx_platform_da
        hw->wiphy->features |= NL80211_FEATURE_AP_SCAN;
        hw->wiphy->flags |= WIPHY_FLAG_AP_PROBE_RESP_OFFLOAD;
        hw->wiphy->flags |= WIPHY_FLAG_AP_UAPSD;
+       hw->wiphy->max_remain_on_channel_duration = 5000;
        hw->wiphy->max_ap_assoc_sta = HIF_LINK_ID_MAX;
        hw->wiphy->max_scan_ssids = 2;
        hw->wiphy->max_scan_ie_len = IEEE80211_MAX_DATA_LEN;

diff --git a/drivers/net/wireless/silabs/wfx/scan.c b/drivers/net/wireless/silabs/wfx/scan.c
index d6f98035f684465ff77dd8369d7aa8df3d7864cf..c3c103ff88cceb21670e5d35af78951259044a59 100644 (file)
--- a/drivers/net/wireless/silabs/wfx/scan.c
+++ b/drivers/net/wireless/silabs/wfx/scan.c
@@ -145,3 +145,65 @@ void wfx_scan_complete(struct wfx_vif *wvif, int nb_chan_done)
        wvif->scan_nb_chan_done = 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->wdev->scan_lock);
+       if (wvif->join_in_progress) {
+               dev_info(wvif->wdev->dev, "abort in-progress REQ_JOIN");
+               wfx_reset(wvif);
+       }
+       wfx_tx_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:
+       mutex_unlock(&wvif->wdev->scan_lock);
+       mutex_unlock(&wvif->wdev->conf_mutex);
+       wfx_bh_request_tx(wvif->wdev);
+}
+
+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 78e3b984f375c0f994884708b2b221df0246d910..995ab8c6cb5ef771f7383acb1256b5f45e40ba71 100644 (file)
--- a/drivers/net/wireless/silabs/wfx/scan.h
+++ b/drivers/net/wireless/silabs/wfx/scan.h
@@ -19,4 +19,10 @@ 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);
+int wfx_cancel_remain_on_channel(struct ieee80211_hw *hw, struct ieee80211_vif *vif);
+
 #endif

diff --git a/drivers/net/wireless/silabs/wfx/sta.c b/drivers/net/wireless/silabs/wfx/sta.c
index 8533bad6caeae4e34ffd3d928cb97772e6f26847..1b6c158457b4290ea4a7f02a54453ee458d9c644 100644 (file)
--- a/drivers/net/wireless/silabs/wfx/sta.c
+++ b/drivers/net/wireless/silabs/wfx/sta.c
@@ -728,6 +728,7 @@ int wfx_add_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
 
        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 a41b2c35fa41504f191d4dc1fa968f79b33ceea1..bd0df2e1ea9901f8821d1420471d7407576c1367 100644 (file)
--- a/drivers/net/wireless/silabs/wfx/wfx.h
+++ b/drivers/net/wireless/silabs/wfx/wfx.h
@@ -70,6 +70,7 @@ struct wfx_vif {
 
        bool                       after_dtim_tx_allowed;
        bool                       join_in_progress;
+       struct completion          set_pm_mode_complete;
 
        struct delayed_work        beacon_loss_work;
 
@@ -87,7 +88,9 @@ 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)