wcn36xx: Implement tx_rate reporting

Currently, the driver reports a tx_rate of 6.0 MBit/s no matter the true
rate:

root@linaro-developer:~# iw wlan0 link
Connected to 6c:f3:7f:eb:9b:92 (on wlan0)
        SSID: SQ-DEVICETEST
        freq: 5200
        RX: 4141 bytes (32 packets)
        TX: 2082 bytes (15 packets)
        signal: -77 dBm
        rx bitrate: 135.0 MBit/s MCS 6 40MHz short GI
        tx bitrate: 6.0 MBit/s

        bss flags:      short-slot-time
        dtim period:    1
        beacon int:     100

This patch requests HAL_GLOBAL_CLASS_A_STATS_INFO via a hal_get_stats
firmware message and reports it via ieee80211_ops::sta_statistics.

root@linaro-developer:~# iw wlan0 link
Connected to 6c:f3:7f:eb:73:b2 (on wlan0)
        SSID: SQ-DEVICETEST
        freq: 5700
        RX: 26788094 bytes (19859 packets)
        TX: 1101376 bytes (12119 packets)
        signal: -75 dBm
        rx bitrate: 135.0 MBit/s MCS 6 40MHz short GI
        tx bitrate: 108.0 MBit/s VHT-MCS 5 40MHz VHT-NSS 1

        bss flags:      short-slot-time
        dtim period:    1
        beacon int:     100

Tested on MSM8939 with WCN3680B running firmware CNSS-PR-2-0-1-2-c1-00083,
and verified by sniffing frames over the air with Wireshark to ensure the
MCS indices match.
Signed-off-by: Edmond Gagnon <egagnon@squareup.com>
Reviewed-by: Benjamin Li <benl@squareup.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20220325224212.159690-1-egagnon@squareup.com

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

@@ -2626,7 +2626,12 @@ enum tx_rate_info {
 	HAL_TX_RATE_SGI = 0x8,
 
 	/* Rate with Long guard interval */
-	HAL_TX_RATE_LGI = 0x10
+	HAL_TX_RATE_LGI = 0x10,
+
+	/* VHT rates */
+	HAL_TX_RATE_VHT20  = 0x20,
+	HAL_TX_RATE_VHT40  = 0x40,
+	HAL_TX_RATE_VHT80  = 0x80,
 };
 
 struct ani_global_class_a_stats_info {

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

@@ -1400,6 +1400,21 @@ static int wcn36xx_get_survey(struct ieee80211_hw *hw, int idx,
 	return 0;
 }
 
+static void wcn36xx_sta_statistics(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
+				   struct ieee80211_sta *sta, struct station_info *sinfo)
+{
+	struct wcn36xx *wcn;
+	u8 sta_index;
+	int status;
+
+	wcn = hw->priv;
+	sta_index = get_sta_index(vif, wcn36xx_sta_to_priv(sta));
+	status = wcn36xx_smd_get_stats(wcn, sta_index, HAL_GLOBAL_CLASS_A_STATS_INFO, sinfo);
+
+	if (status)
+		wcn36xx_err("wcn36xx_smd_get_stats failed\n");
+}
+
 static const struct ieee80211_ops wcn36xx_ops = {
 	.start			= wcn36xx_start,
 	.stop			= wcn36xx_stop,
@@ -1423,6 +1438,7 @@ static const struct ieee80211_ops wcn36xx_ops = {
 	.set_rts_threshold	= wcn36xx_set_rts_threshold,
 	.sta_add		= wcn36xx_sta_add,
 	.sta_remove		= wcn36xx_sta_remove,
+	.sta_statistics		= wcn36xx_sta_statistics,
 	.ampdu_action		= wcn36xx_ampdu_action,
 #if IS_ENABLED(CONFIG_IPV6)
 	.ipv6_addr_change	= wcn36xx_ipv6_addr_change,

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

@@ -2627,6 +2627,62 @@ int wcn36xx_smd_del_ba(struct wcn36xx *wcn, u16 tid, u8 direction, u8 sta_index)
 	return ret;
 }
 
+int wcn36xx_smd_get_stats(struct wcn36xx *wcn, u8 sta_index, u32 stats_mask,
+			  struct station_info *sinfo)
+{
+	struct wcn36xx_hal_stats_req_msg msg_body;
+	struct wcn36xx_hal_stats_rsp_msg *rsp;
+	void *rsp_body;
+	int ret;
+
+	if (stats_mask & ~HAL_GLOBAL_CLASS_A_STATS_INFO) {
+		wcn36xx_err("stats_mask 0x%x contains unimplemented types\n",
+			    stats_mask);
+		return -EINVAL;
+	}
+
+	mutex_lock(&wcn->hal_mutex);
+	INIT_HAL_MSG(msg_body, WCN36XX_HAL_GET_STATS_REQ);
+
+	msg_body.sta_id = sta_index;
+	msg_body.stats_mask = stats_mask;
+
+	PREPARE_HAL_BUF(wcn->hal_buf, msg_body);
+
+	ret = wcn36xx_smd_send_and_wait(wcn, msg_body.header.len);
+	if (ret) {
+		wcn36xx_err("sending hal_get_stats failed\n");
+		goto out;
+	}
+
+	ret = wcn36xx_smd_rsp_status_check(wcn->hal_buf, wcn->hal_rsp_len);
+	if (ret) {
+		wcn36xx_err("hal_get_stats response failed err=%d\n", ret);
+		goto out;
+	}
+
+	rsp = (struct wcn36xx_hal_stats_rsp_msg *)wcn->hal_buf;
+	rsp_body = (wcn->hal_buf + sizeof(struct wcn36xx_hal_stats_rsp_msg));
+
+	if (rsp->stats_mask != stats_mask) {
+		wcn36xx_err("stats_mask 0x%x differs from requested 0x%x\n",
+			    rsp->stats_mask, stats_mask);
+		goto out;
+	}
+
+	if (rsp->stats_mask & HAL_GLOBAL_CLASS_A_STATS_INFO) {
+		struct ani_global_class_a_stats_info *stats_info = rsp_body;
+
+		wcn36xx_process_tx_rate(stats_info, &sinfo->txrate);
+		sinfo->filled |= BIT_ULL(NL80211_STA_INFO_TX_BITRATE);
+		rsp_body += sizeof(struct ani_global_class_a_stats_info);
+	}
+out:
+	mutex_unlock(&wcn->hal_mutex);
+
+	return ret;
+}
+
 static int wcn36xx_smd_trigger_ba_rsp(void *buf, int len, struct add_ba_info *ba_info)
 {
 	struct wcn36xx_hal_trigger_ba_rsp_candidate *candidate;
@@ -3316,6 +3372,7 @@ int wcn36xx_smd_rsp_process(struct rpmsg_device *rpdev,
 	case WCN36XX_HAL_ADD_BA_SESSION_RSP:
 	case WCN36XX_HAL_ADD_BA_RSP:
 	case WCN36XX_HAL_DEL_BA_RSP:
+	case WCN36XX_HAL_GET_STATS_RSP:
 	case WCN36XX_HAL_TRIGGER_BA_RSP:
 	case WCN36XX_HAL_UPDATE_CFG_RSP:
 	case WCN36XX_HAL_JOIN_RSP:

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

@@ -138,6 +138,8 @@ int wcn36xx_smd_add_ba_session(struct wcn36xx *wcn,
 int wcn36xx_smd_add_ba(struct wcn36xx *wcn, u8 session_id);
 int wcn36xx_smd_del_ba(struct wcn36xx *wcn, u16 tid, u8 direction, u8 sta_index);
 int wcn36xx_smd_trigger_ba(struct wcn36xx *wcn, u8 sta_index, u16 tid, u16 *ssn);
+int wcn36xx_smd_get_stats(struct wcn36xx *wcn, u8 sta_index, u32 stats_mask,
+			  struct station_info *sinfo);
 
 int wcn36xx_smd_update_cfg(struct wcn36xx *wcn, u32 cfg_id, u32 value);
 

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

@@ -699,3 +699,32 @@ int wcn36xx_start_tx(struct wcn36xx *wcn,
 
 	return ret;
 }
+
+void wcn36xx_process_tx_rate(struct ani_global_class_a_stats_info *stats, struct rate_info *info)
+{
+	/* tx_rate is in units of 500kbps; mac80211 wants them in 100kbps */
+	if (stats->tx_rate_flags & HAL_TX_RATE_LEGACY)
+		info->legacy = stats->tx_rate * 5;
+
+	info->flags = 0;
+	info->mcs = stats->mcs_index;
+	info->nss = 1;
+
+	if (stats->tx_rate_flags & (HAL_TX_RATE_HT20 | HAL_TX_RATE_HT40))
+		info->flags |= RATE_INFO_FLAGS_MCS;
+
+	if (stats->tx_rate_flags & (HAL_TX_RATE_VHT20 | HAL_TX_RATE_VHT40 | HAL_TX_RATE_VHT80))
+		info->flags |= RATE_INFO_FLAGS_VHT_MCS;
+
+	if (stats->tx_rate_flags & HAL_TX_RATE_SGI)
+		info->flags |= RATE_INFO_FLAGS_SHORT_GI;
+
+	if (stats->tx_rate_flags & (HAL_TX_RATE_HT20 | HAL_TX_RATE_VHT20))
+		info->bw = RATE_INFO_BW_20;
+
+	if (stats->tx_rate_flags & (HAL_TX_RATE_HT40 | HAL_TX_RATE_VHT40))
+		info->bw = RATE_INFO_BW_40;
+
+	if (stats->tx_rate_flags & HAL_TX_RATE_VHT80)
+		info->bw = RATE_INFO_BW_80;
+}

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

@@ -164,5 +164,6 @@ int  wcn36xx_rx_skb(struct wcn36xx *wcn, struct sk_buff *skb);
 int wcn36xx_start_tx(struct wcn36xx *wcn,
 		     struct wcn36xx_sta *sta_priv,
 		     struct sk_buff *skb);
+void wcn36xx_process_tx_rate(struct ani_global_class_a_stats_info *stats, struct rate_info *info);
 
 #endif	/* _TXRX_H_ */