ath10k: add wmi command barrier utility

This allows placing command barriers for explicit
serializing and synchronizing state.

Useful for future driver development.
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/ath10k/core.h

@@ -142,6 +142,7 @@ struct ath10k_wmi {
 	enum ath10k_htc_ep_id eid;
 	struct completion service_ready;
 	struct completion unified_ready;
+	struct completion barrier;
 	wait_queue_head_t tx_credits_wq;
 	DECLARE_BITMAP(svc_map, WMI_SERVICE_MAX);
 	struct wmi_cmd_map *cmd;

drivers/net/wireless/ath/ath10k/wmi.c

@@ -29,6 +29,9 @@
 #include "p2p.h"
 #include "hw.h"
 
+#define ATH10K_WMI_BARRIER_ECHO_ID 0xBA991E9
+#define ATH10K_WMI_BARRIER_TIMEOUT_HZ (3 * HZ)
+
 /* MAIN WMI cmd track */
 static struct wmi_cmd_map wmi_cmd_map = {
 	.init_cmdid = WMI_INIT_CMDID,
@@ -2507,6 +2510,9 @@ void ath10k_wmi_event_echo(struct ath10k *ar, struct sk_buff *skb)
 	ath10k_dbg(ar, ATH10K_DBG_WMI,
 		   "wmi event echo value 0x%08x\n",
 		   le32_to_cpu(arg.value));
+
+	if (le32_to_cpu(arg.value) == ATH10K_WMI_BARRIER_ECHO_ID)
+		complete(&ar->wmi.barrier);
 }
 
 int ath10k_wmi_event_debug_mesg(struct ath10k *ar, struct sk_buff *skb)
@@ -7715,6 +7721,30 @@ ath10k_wmi_op_gen_echo(struct ath10k *ar, u32 value)
 	return skb;
 }
 
+int
+ath10k_wmi_barrier(struct ath10k *ar)
+{
+	int ret;
+	int time_left;
+
+	spin_lock_bh(&ar->data_lock);
+	reinit_completion(&ar->wmi.barrier);
+	spin_unlock_bh(&ar->data_lock);
+
+	ret = ath10k_wmi_echo(ar, ATH10K_WMI_BARRIER_ECHO_ID);
+	if (ret) {
+		ath10k_warn(ar, "failed to submit wmi echo: %d\n", ret);
+		return ret;
+	}
+
+	time_left = wait_for_completion_timeout(&ar->wmi.barrier,
+						ATH10K_WMI_BARRIER_TIMEOUT_HZ);
+	if (!time_left)
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
 static const struct wmi_ops wmi_ops = {
 	.rx = ath10k_wmi_op_rx,
 	.map_svc = wmi_main_svc_map,
@@ -8112,6 +8142,7 @@ int ath10k_wmi_attach(struct ath10k *ar)
 
 	init_completion(&ar->wmi.service_ready);
 	init_completion(&ar->wmi.unified_ready);
+	init_completion(&ar->wmi.barrier);
 
 	INIT_WORK(&ar->svc_rdy_work, ath10k_wmi_event_service_ready_work);
 

drivers/net/wireless/ath/ath10k/wmi.h

@@ -6628,5 +6628,6 @@ void ath10k_wmi_10_4_op_fw_stats_fill(struct ath10k *ar,
 				      char *buf);
 int ath10k_wmi_op_get_vdev_subtype(struct ath10k *ar,
 				   enum wmi_vdev_subtype subtype);
+int ath10k_wmi_barrier(struct ath10k *ar);
 
 #endif /* _WMI_H_ */