qtnfmac: add DFS offload support

DFS offload support implemented:
- DFS_OFFLOAD feature is advertised depending on HW capabilities
- CAC_STARTED event forwarding from HW implemented
- start_radar_detection() callback now returning -ENOTSUPP
  if DFS_OFFLOAD is enabled
Signed-off-by: Dmitry Lebed <dlebed@quantenna.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/quantenna/qtnfmac/cfg80211.c

@@ -813,6 +813,9 @@ static int qtnf_start_radar_detection(struct wiphy *wiphy,
 	struct qtnf_vif *vif = qtnf_netdev_get_priv(ndev);
 	int ret;
 
+	if (wiphy_ext_feature_isset(wiphy, NL80211_EXT_FEATURE_DFS_OFFLOAD))
+		return -ENOTSUPP;
+
 	ret = qtnf_cmd_start_cac(vif, chandef, cac_time_ms);
 	if (ret)
 		pr_err("%s: failed to start CAC ret=%d\n", ndev->name, ret);
@@ -909,6 +912,9 @@ struct wiphy *qtnf_wiphy_allocate(struct qtnf_bus *bus)
 {
 	struct wiphy *wiphy;
 
+	if (bus->hw_info.hw_capab & QLINK_HW_CAPAB_DFS_OFFLOAD)
+		qtn_cfg80211_ops.start_radar_detection = NULL;
+
 	wiphy = wiphy_new(&qtn_cfg80211_ops, sizeof(struct qtnf_wmac));
 	if (!wiphy)
 		return NULL;
@@ -982,6 +988,9 @@ int qtnf_wiphy_register(struct qtnf_hw_info *hw_info, struct qtnf_wmac *mac)
 			WIPHY_FLAG_AP_UAPSD |
 			WIPHY_FLAG_HAS_CHANNEL_SWITCH;
 
+	if (hw_info->hw_capab & QLINK_HW_CAPAB_DFS_OFFLOAD)
+		wiphy_ext_feature_set(wiphy, NL80211_EXT_FEATURE_DFS_OFFLOAD);
+
 	wiphy->probe_resp_offload = NL80211_PROBE_RESP_OFFLOAD_SUPPORT_WPS |
 				    NL80211_PROBE_RESP_OFFLOAD_SUPPORT_WPS2;
 

drivers/net/wireless/quantenna/qtnfmac/event.c

@@ -443,6 +443,17 @@ static int qtnf_event_handle_radar(struct qtnf_vif *vif,
 		cfg80211_cac_event(vif->netdev, &chandef,
 				   NL80211_RADAR_CAC_ABORTED, GFP_KERNEL);
 		break;
+	case QLINK_RADAR_CAC_STARTED:
+		if (vif->wdev.cac_started)
+			break;
+
+		if (!wiphy_ext_feature_isset(wiphy,
+					     NL80211_EXT_FEATURE_DFS_OFFLOAD))
+			break;
+
+		cfg80211_cac_event(vif->netdev, &chandef,
+				   NL80211_RADAR_CAC_STARTED, GFP_KERNEL);
+		break;
 	default:
 		pr_warn("%s: unhandled radar event %u\n",
 			vif->netdev->name, ev->event);

drivers/net/wireless/quantenna/qtnfmac/qlink.h

@@ -68,10 +68,12 @@ struct qlink_msg_header {
  * @QLINK_HW_CAPAB_STA_INACT_TIMEOUT: device implements a logic to kick-out
  *	associated STAs due to inactivity. Inactivity timeout period is taken
  *	from QLINK_CMD_START_AP parameters.
+ * @QLINK_HW_CAPAB_DFS_OFFLOAD: device implements DFS offload functionality
  */
 enum qlink_hw_capab {
 	QLINK_HW_CAPAB_REG_UPDATE		= BIT(0),
 	QLINK_HW_CAPAB_STA_INACT_TIMEOUT	= BIT(1),
+	QLINK_HW_CAPAB_DFS_OFFLOAD		= BIT(2),
 };
 
 enum qlink_iface_type {
@@ -1031,6 +1033,7 @@ enum qlink_radar_event {
 	QLINK_RADAR_CAC_ABORTED,
 	QLINK_RADAR_NOP_FINISHED,
 	QLINK_RADAR_PRE_CAC_EXPIRED,
+	QLINK_RADAR_CAC_STARTED,
 };
 
 /**