wcn36xx: Add hardware scan offload support

Current hw_scan implementation does not trigger offloaded
hardware scan and seems to only put the device in a kind of
listening mode (beacon/probe-response) for software scan.
Since no probe request are generated by the software, current
scanning method is similar to a passive scan.

This patch introduces support for 'true' hardware offloaded scan.
Hardware scan is configured and started via the start-scan-offload
firmware message. Once scan has been completed a scan indicator
message is received from firmware.

Moreover, this patch includes support for directed probe-request,
allowing connection with hidden APs. It also fixes scan issues with
band-steering AP which are not 'visible' with passive scan (due to
hidden ssid in beacons).

Let's keep the 'legacy' scanning method in case scan-offload is not
supported.
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/wcn36xx/hal.h

@@ -348,6 +348,13 @@ enum wcn36xx_hal_host_msg_type {
 	WCN36XX_HAL_DHCP_START_IND = 189,
 	WCN36XX_HAL_DHCP_STOP_IND = 190,
 
+	/* Scan Offload(hw) APIs */
+	WCN36XX_HAL_START_SCAN_OFFLOAD_REQ = 204,
+	WCN36XX_HAL_START_SCAN_OFFLOAD_RSP = 205,
+	WCN36XX_HAL_STOP_SCAN_OFFLOAD_REQ = 206,
+	WCN36XX_HAL_STOP_SCAN_OFFLOAD_RSP = 207,
+	WCN36XX_HAL_SCAN_OFFLOAD_IND = 210,
+
 	WCN36XX_HAL_AVOID_FREQ_RANGE_IND = 233,
 
 	WCN36XX_HAL_PRINT_REG_INFO_IND = 259,
@@ -1115,6 +1122,101 @@ struct wcn36xx_hal_finish_scan_rsp_msg {
 
 } __packed;
 
+enum wcn36xx_hal_scan_type {
+	WCN36XX_HAL_SCAN_TYPE_PASSIVE = 0x00,
+	WCN36XX_HAL_SCAN_TYPE_ACTIVE = WCN36XX_HAL_MAX_ENUM_SIZE
+};
+
+struct wcn36xx_hal_mac_ssid {
+	u8 length;
+	u8 ssid[32];
+} __packed;
+
+struct wcn36xx_hal_start_scan_offload_req_msg {
+	struct wcn36xx_hal_msg_header header;
+
+	/* BSSIDs hot list */
+	u8 num_bssid;
+	u8 bssids[4][ETH_ALEN];
+
+	/* Directed probe-requests will be sent for listed SSIDs (max 10)*/
+	u8 num_ssid;
+	struct wcn36xx_hal_mac_ssid ssids[10];
+
+	/* Report AP with hidden ssid */
+	u8 scan_hidden;
+
+	/* Self MAC address */
+	u8 mac[ETH_ALEN];
+
+	/* BSS type */
+	enum wcn36xx_hal_bss_type bss_type;
+
+	/* Scan type */
+	enum wcn36xx_hal_scan_type scan_type;
+
+	/* Minimum scanning time on each channel (ms) */
+	u32 min_ch_time;
+
+	/* Maximum scanning time on each channel */
+	u32 max_ch_time;
+
+	/* Is a p2p search */
+	u8 p2p_search;
+
+	/* Channels to scan */
+	u8 num_channel;
+	u8 channels[80];
+
+	/* IE field */
+	u16 ie_len;
+	u8 ie[0];
+} __packed;
+
+struct wcn36xx_hal_start_scan_offload_rsp_msg {
+	struct wcn36xx_hal_msg_header header;
+
+	/* success or failure */
+	u32 status;
+} __packed;
+
+enum wcn36xx_hal_scan_offload_ind_type {
+	/* Scan has been started */
+	WCN36XX_HAL_SCAN_IND_STARTED = 0x01,
+	/* Scan has been completed */
+	WCN36XX_HAL_SCAN_IND_COMPLETED = 0x02,
+	/* Moved to foreign channel */
+	WCN36XX_HAL_SCAN_IND_FOREIGN_CHANNEL = 0x08,
+	/* scan request has been dequeued */
+	WCN36XX_HAL_SCAN_IND_DEQUEUED = 0x10,
+	/* preempted by other high priority scan */
+	WCN36XX_HAL_SCAN_IND_PREEMPTED = 0x20,
+	/* scan start failed */
+	WCN36XX_HAL_SCAN_IND_FAILED = 0x40,
+	 /*scan restarted */
+	WCN36XX_HAL_SCAN_IND_RESTARTED = 0x80,
+	WCN36XX_HAL_SCAN_IND_MAX = WCN36XX_HAL_MAX_ENUM_SIZE
+};
+
+struct wcn36xx_hal_scan_offload_ind {
+	struct wcn36xx_hal_msg_header header;
+
+	u32 type;
+	u32 channel_mhz;
+	u32 scan_id;
+} __packed;
+
+struct wcn36xx_hal_stop_scan_offload_req_msg {
+	struct wcn36xx_hal_msg_header header;
+} __packed;
+
+struct wcn36xx_hal_stop_scan_offload_rsp_msg {
+	struct wcn36xx_hal_msg_header header;
+
+	/* success or failure */
+	u32 status;
+} __packed;
+
 enum wcn36xx_hal_rate_index {
 	HW_RATE_INDEX_1MBPS	= 0x82,
 	HW_RATE_INDEX_2MBPS	= 0x84,
@@ -1507,11 +1609,6 @@ struct wcn36xx_hal_edca_param_record {
 	u16 txop_limit;
 } __packed;
 
-struct wcn36xx_hal_mac_ssid {
-	u8 length;
-	u8 ssid[32];
-} __packed;
-
 /* Concurrency role. These are generic IDs that identify the various roles
  *  in the software system. */
 enum wcn36xx_hal_con_mode {

drivers/net/wireless/ath/wcn36xx/main.c

@@ -629,7 +629,6 @@ static int wcn36xx_hw_scan(struct ieee80211_hw *hw,
 			   struct ieee80211_scan_request *hw_req)
 {
 	struct wcn36xx *wcn = hw->priv;
-
 	mutex_lock(&wcn->scan_lock);
 	if (wcn->scan_req) {
 		mutex_unlock(&wcn->scan_lock);
@@ -638,11 +637,16 @@ static int wcn36xx_hw_scan(struct ieee80211_hw *hw,
 
 	wcn->scan_aborted = false;
 	wcn->scan_req = &hw_req->req;
+
 	mutex_unlock(&wcn->scan_lock);
 
+	if (!get_feat_caps(wcn->fw_feat_caps, SCAN_OFFLOAD)) {
+		/* legacy manual/sw scan */
 		schedule_work(&wcn->scan_work);
-
 		return 0;
+	}
+
+	return wcn36xx_smd_start_hw_scan(wcn, vif, &hw_req->req);
 }
 
 static void wcn36xx_cancel_hw_scan(struct ieee80211_hw *hw,
@@ -650,6 +654,12 @@ static void wcn36xx_cancel_hw_scan(struct ieee80211_hw *hw,
 {
 	struct wcn36xx *wcn = hw->priv;
 
+	if (!wcn36xx_smd_stop_hw_scan(wcn)) {
+		struct cfg80211_scan_info scan_info = { .aborted = true };
+
+		ieee80211_scan_completed(wcn->hw, &scan_info);
+	}
+
 	mutex_lock(&wcn->scan_lock);
 	wcn->scan_aborted = true;
 	mutex_unlock(&wcn->scan_lock);

drivers/net/wireless/ath/wcn36xx/smd.c

@@ -615,6 +615,85 @@ int wcn36xx_smd_finish_scan(struct wcn36xx *wcn,
 	return ret;
 }
 
+int wcn36xx_smd_start_hw_scan(struct wcn36xx *wcn, struct ieee80211_vif *vif,
+			      struct cfg80211_scan_request *req)
+{
+	struct wcn36xx_hal_start_scan_offload_req_msg msg_body;
+	int ret, i;
+
+	mutex_lock(&wcn->hal_mutex);
+	INIT_HAL_MSG(msg_body, WCN36XX_HAL_START_SCAN_OFFLOAD_REQ);
+
+	msg_body.scan_type = WCN36XX_HAL_SCAN_TYPE_ACTIVE;
+	msg_body.min_ch_time = 30;
+	msg_body.min_ch_time = 100;
+	msg_body.scan_hidden = 1;
+	memcpy(msg_body.mac, vif->addr, ETH_ALEN);
+	msg_body.p2p_search = vif->p2p;
+
+	msg_body.num_ssid = min_t(u8, req->n_ssids, ARRAY_SIZE(msg_body.ssids));
+	for (i = 0; i < msg_body.num_ssid; i++) {
+		msg_body.ssids[i].length = min_t(u8, req->ssids[i].ssid_len,
+						sizeof(msg_body.ssids[i].ssid));
+		memcpy(msg_body.ssids[i].ssid, req->ssids[i].ssid,
+		       msg_body.ssids[i].length);
+	}
+
+	msg_body.num_channel = min_t(u8, req->n_channels,
+				     sizeof(msg_body.channels));
+	for (i = 0; i < msg_body.num_channel; i++)
+		msg_body.channels[i] = req->channels[i]->hw_value;
+
+	PREPARE_HAL_BUF(wcn->hal_buf, msg_body);
+
+	wcn36xx_dbg(WCN36XX_DBG_HAL,
+		    "hal start hw-scan (channels: %u; ssids: %u; p2p: %s)\n",
+		    msg_body.num_channel, msg_body.num_ssid,
+		    msg_body.p2p_search ? "yes" : "no");
+
+	ret = wcn36xx_smd_send_and_wait(wcn, msg_body.header.len);
+	if (ret) {
+		wcn36xx_err("Sending hal_start_scan_offload failed\n");
+		goto out;
+	}
+	ret = wcn36xx_smd_rsp_status_check(wcn->hal_buf, wcn->hal_rsp_len);
+	if (ret) {
+		wcn36xx_err("hal_start_scan_offload response failed err=%d\n",
+			    ret);
+		goto out;
+	}
+out:
+	mutex_unlock(&wcn->hal_mutex);
+	return ret;
+}
+
+int wcn36xx_smd_stop_hw_scan(struct wcn36xx *wcn)
+{
+	struct wcn36xx_hal_stop_scan_offload_req_msg msg_body;
+	int ret;
+
+	mutex_lock(&wcn->hal_mutex);
+	INIT_HAL_MSG(msg_body, WCN36XX_HAL_STOP_SCAN_OFFLOAD_REQ);
+	PREPARE_HAL_BUF(wcn->hal_buf, msg_body);
+
+	wcn36xx_dbg(WCN36XX_DBG_HAL, "hal stop hw-scan\n");
+
+	ret = wcn36xx_smd_send_and_wait(wcn, msg_body.header.len);
+	if (ret) {
+		wcn36xx_err("Sending hal_stop_scan_offload failed\n");
+		goto out;
+	}
+	ret = wcn36xx_smd_rsp_status_check(wcn->hal_buf, wcn->hal_rsp_len);
+	if (ret) {
+		wcn36xx_err("hal_stop_scan_offload response failed err=%d\n",
+			    ret);
+		goto out;
+	}
+out:
+	mutex_unlock(&wcn->hal_mutex);
+	return ret;
+}
+
 static int wcn36xx_smd_switch_channel_rsp(void *buf, size_t len)
 {
 	struct wcn36xx_hal_switch_channel_rsp_msg *rsp;
@@ -2041,6 +2120,40 @@ static int wcn36xx_smd_tx_compl_ind(struct wcn36xx *wcn, void *buf, size_t len)
 	return 0;
 }
 
+static int wcn36xx_smd_hw_scan_ind(struct wcn36xx *wcn, void *buf, size_t len)
+{
+	struct wcn36xx_hal_scan_offload_ind *rsp = buf;
+	struct cfg80211_scan_info scan_info = {};
+
+	if (len != sizeof(*rsp)) {
+		wcn36xx_warn("Corrupted delete scan indication\n");
+		return -EIO;
+	}
+
+	wcn36xx_dbg(WCN36XX_DBG_HAL, "scan indication (type %x)", rsp->type);
+
+	switch (rsp->type) {
+	case WCN36XX_HAL_SCAN_IND_FAILED:
+		scan_info.aborted = true;
+	case WCN36XX_HAL_SCAN_IND_COMPLETED:
+		mutex_lock(&wcn->scan_lock);
+		wcn->scan_req = NULL;
+		mutex_unlock(&wcn->scan_lock);
+		ieee80211_scan_completed(wcn->hw, &scan_info);
+		break;
+	case WCN36XX_HAL_SCAN_IND_STARTED:
+	case WCN36XX_HAL_SCAN_IND_FOREIGN_CHANNEL:
+	case WCN36XX_HAL_SCAN_IND_DEQUEUED:
+	case WCN36XX_HAL_SCAN_IND_PREEMPTED:
+	case WCN36XX_HAL_SCAN_IND_RESTARTED:
+		break;
+	default:
+		wcn36xx_warn("Unknown scan indication type %x\n", rsp->type);
+	}
+
+	return 0;
+}
+
 static int wcn36xx_smd_missed_beacon_ind(struct wcn36xx *wcn,
 					 void *buf,
 					 size_t len)
@@ -2252,6 +2365,8 @@ int wcn36xx_smd_rsp_process(struct rpmsg_device *rpdev,
 	case WCN36XX_HAL_CH_SWITCH_RSP:
 	case WCN36XX_HAL_FEATURE_CAPS_EXCHANGE_RSP:
 	case WCN36XX_HAL_8023_MULTICAST_LIST_RSP:
+	case WCN36XX_HAL_START_SCAN_OFFLOAD_RSP:
+	case WCN36XX_HAL_STOP_SCAN_OFFLOAD_RSP:
 		memcpy(wcn->hal_buf, buf, len);
 		wcn->hal_rsp_len = len;
 		complete(&wcn->hal_rsp_compl);
@@ -2264,6 +2379,7 @@ int wcn36xx_smd_rsp_process(struct rpmsg_device *rpdev,
 	case WCN36XX_HAL_MISSED_BEACON_IND:
 	case WCN36XX_HAL_DELETE_STA_CONTEXT_IND:
 	case WCN36XX_HAL_PRINT_REG_INFO_IND:
+	case WCN36XX_HAL_SCAN_OFFLOAD_IND:
 		msg_ind = kmalloc(sizeof(*msg_ind) + len, GFP_ATOMIC);
 		if (!msg_ind) {
 			wcn36xx_err("Run out of memory while handling SMD_EVENT (%d)\n",
@@ -2328,6 +2444,10 @@ static void wcn36xx_ind_smd_work(struct work_struct *work)
 					       hal_ind_msg->msg,
 					       hal_ind_msg->msg_len);
 		break;
+	case WCN36XX_HAL_SCAN_OFFLOAD_IND:
+		wcn36xx_smd_hw_scan_ind(wcn, hal_ind_msg->msg,
+					hal_ind_msg->msg_len);
+		break;
 	default:
 		wcn36xx_err("SMD_EVENT (%d) not supported\n",
 			      msg_header->msg_type);

drivers/net/wireless/ath/wcn36xx/smd.h

@@ -65,6 +65,9 @@ int wcn36xx_smd_end_scan(struct wcn36xx *wcn, u8 scan_channel);
 int wcn36xx_smd_finish_scan(struct wcn36xx *wcn,
 			    enum wcn36xx_hal_sys_mode mode);
 int wcn36xx_smd_update_scan_params(struct wcn36xx *wcn, u8 *channels, size_t channel_count);
+int wcn36xx_smd_start_hw_scan(struct wcn36xx *wcn, struct ieee80211_vif *vif,
+			      struct cfg80211_scan_request *req);
+int wcn36xx_smd_stop_hw_scan(struct wcn36xx *wcn);
 int wcn36xx_smd_add_sta_self(struct wcn36xx *wcn, struct ieee80211_vif *vif);
 int wcn36xx_smd_delete_sta_self(struct wcn36xx *wcn, u8 *addr);
 int wcn36xx_smd_delete_sta(struct wcn36xx *wcn, u8 sta_index);