wcn36xx: Add Host suspend indication support

In order to activate ipv4 ARP offload, ipv6 NS offload and firmware GTK
offload we need to send a unidirectional indication from host to wcn
indicating a transition to suspend.

Once done, firmware will respond to ARP broadcasts, ipv6 NS lookups and
perform GTK rekeys without waking the host.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Tested-by: Benjamin Li <benl@squareup.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210605011140.2004643-11-bryan.odonoghue@linaro.org

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

@@ -1125,6 +1125,9 @@ static int wcn36xx_suspend(struct ieee80211_hw *hw, struct cfg80211_wowlan *wow)
 		if (ret)
 			goto out;
 		ret = wcn36xx_smd_set_power_params(wcn, true);
+		if (ret)
+			goto out;
+		ret = wcn36xx_smd_wlan_host_suspend_ind(wcn);
 	}
 out:
 	mutex_unlock(&wcn->conf_mutex);

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

@@ -2966,6 +2966,25 @@ int wcn36xx_smd_gtk_offload_get_info(struct wcn36xx *wcn,
 	return ret;
 }
 
+int wcn36xx_smd_wlan_host_suspend_ind(struct wcn36xx *wcn)
+{
+	struct wcn36xx_hal_wlan_host_suspend_ind_msg msg_body;
+	int ret;
+
+	mutex_lock(&wcn->hal_mutex);
+
+	INIT_HAL_MSG(msg_body, WCN36XX_HAL_HOST_SUSPEND_IND);
+	msg_body.configured_mcst_bcst_filter_setting = 0;
+	msg_body.active_session_count = 1;
+	PREPARE_HAL_BUF(wcn->hal_buf, msg_body);
+
+	ret = rpmsg_send(wcn->smd_channel, wcn->hal_buf, msg_body.header.len);
+
+	mutex_unlock(&wcn->hal_mutex);
+
+	return ret;
+}
+
 int wcn36xx_smd_rsp_process(struct rpmsg_device *rpdev,
 			    void *buf, int len, void *priv, u32 addr)
 {

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

@@ -159,4 +159,6 @@ int wcn36xx_smd_gtk_offload(struct wcn36xx *wcn, struct ieee80211_vif *vif,
 int wcn36xx_smd_gtk_offload_get_info(struct wcn36xx *wcn,
 				     struct ieee80211_vif *vif);
 
+int wcn36xx_smd_wlan_host_suspend_ind(struct wcn36xx *wcn);
+
 #endif	/* _SMD_H_ */