rsi: fix occasional initialisation failure with BT coex

When BT coexistence is enabled (eg oper mode 13, which is the default)
the initialisation on startup sometimes silently fails.

In a normal initialisation we see
	usb 1-1.3: Product: Wireless USB Network Module
	usb 1-1.3: Manufacturer: Redpine Signals, Inc.
	usb 1-1.3: SerialNumber: 000000000001
	rsi_91x: rsi_probe: Initialized os intf ops
	rsi_91x: rsi_load_9116_firmware: Loading chunk 0
	rsi_91x: rsi_load_9116_firmware: Loading chunk 1
	rsi_91x: rsi_load_9116_firmware: Loading chunk 2
	rsi_91x: Max Stations Allowed = 1

But sometimes the last log is missing and the wlan net device is
not created.

Running a userspace loop that resets the hardware via a GPIO shows the
problem occurring ~5/100 resets.

The problem does not occur in oper mode 1 (wifi only).

Adding logs shows that the initialisation state machine requests a MAC
reset via rsi_send_reset_mac() but the firmware does not reply, leading
to the initialisation sequence being incomplete.

Fix this by delaying attaching the BT adapter until the wifi
initialisation has completed.

With this applied I have done > 300 reset loops with no errors.

Fixes: 716b840 ("rsi: handle BT traffic in driver")
Signed-off-by: Martin Fuzzey <martin.fuzzey@flowbird.group>
CC: stable@vger.kernel.org
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1630337206-12410-2-git-send-email-martin.fuzzey@flowbird.group

drivers/net/wireless/rsi/rsi_91x_main.c

@@ -211,9 +211,10 @@ int rsi_read_pkt(struct rsi_common *common, u8 *rx_pkt, s32 rcv_pkt_len)
 			bt_pkt_type = frame_desc[offset + BT_RX_PKT_TYPE_OFST];
 			if (bt_pkt_type == BT_CARD_READY_IND) {
 				rsi_dbg(INFO_ZONE, "BT Card ready recvd\n");
-				if (rsi_bt_ops.attach(common, &g_proto_ops))
-					rsi_dbg(ERR_ZONE,
-						"Failed to attach BT module\n");
+				if (common->fsm_state == FSM_MAC_INIT_DONE)
+					rsi_attach_bt(common);
+				else
+					common->bt_defer_attach = true;
 			} else {
 				if (common->bt_adapter)
 					rsi_bt_ops.recv_pkt(common->bt_adapter,
@@ -278,6 +279,15 @@ void rsi_set_bt_context(void *priv, void *bt_context)
 }
 #endif
 
+void rsi_attach_bt(struct rsi_common *common)
+{
+#ifdef CONFIG_RSI_COEX
+	if (rsi_bt_ops.attach(common, &g_proto_ops))
+		rsi_dbg(ERR_ZONE,
+			"Failed to attach BT module\n");
+#endif
+}
+
 /**
  * rsi_91x_init() - This function initializes os interface operations.
  * @oper_mode: One of DEV_OPMODE_*.

drivers/net/wireless/rsi/rsi_91x_mgmt.c

@@ -2071,6 +2071,9 @@ static int rsi_handle_ta_confirm_type(struct rsi_common *common,
 				if (common->reinit_hw) {
 					complete(&common->wlan_init_completion);
 				} else {
+					if (common->bt_defer_attach)
+						rsi_attach_bt(common);
+
 					return rsi_mac80211_attach(common);
 				}
 			}

drivers/net/wireless/rsi/rsi_main.h

@@ -320,6 +320,7 @@ struct rsi_common {
 	struct ieee80211_vif *roc_vif;
 
 	bool eapol4_confirm;
+	bool bt_defer_attach;
 	void *bt_adapter;
 
 	struct cfg80211_scan_request *hwscan;
@@ -401,5 +402,6 @@ struct rsi_host_intf_ops {
 
 enum rsi_host_intf rsi_get_host_intf(void *priv);
 void rsi_set_bt_context(void *priv, void *bt_context);
+void rsi_attach_bt(struct rsi_common *common);
 
 #endif