qcacld: [HIF] host crash during the test for BT BNEP profile

The disconnect happened duing probe stage and it casued probe fail.
The disconnect was caused by cold reset which was executed in disconnect
callback.It needs to add a wait mechanism in driver unloading to
prevent the race condition between rmmod procedure and Khubd process.

Change-Id: If5f1d31e6e5d91e0f721412dd9d3a9e82659bd04
CRs-Fixed: 697887

1 files changed, 68 insertions, 6 deletions

diff --git a/CORE/SERVICES/HIF/USB/if_usb.c b/CORE/SERVICES/HIF/USB/if_usb.c
index e71adc827a4c..0a8d11ff4b93 100644
--- a/CORE/SERVICES/HIF/USB/if_usb.c
+++ b/CORE/SERVICES/HIF/USB/if_usb.c
@@ -61,7 +61,18 @@
 
 unsigned int msienable;
 module_param(msienable, int, 0644);
-struct hif_usb_softc *usb_sc;
+#define HIF_USB_UNLOAD_TIMEOUT		(2*HZ)
+enum hif_usb_drv_unload_state {
+	HIF_USB_UNLOAD_STATE_NULL = 0,
+	HIF_USB_UNLOAD_STATE_DRV_DEREG,
+	HIF_USB_UNLOAD_STATE_TARGET_RESET,
+	HIF_USB_UNLOAD_STATE_DEV_DISCONNECTED,
+};
+
+static int hif_usb_unload_dev_num = -1;
+static wait_queue_head_t hif_usb_unload_event_wq;
+static atomic_t hif_usb_unload_state;
+struct hif_usb_softc *usb_sc = NULL;
 static int hif_usb_resume(struct usb_interface *interface);
 
 static int
@@ -69,6 +80,7 @@ hif_usb_configure(struct hif_usb_softc *sc, hif_handle_t *hif_hdl,
 		  struct usb_interface *interface)
 {
 	int ret = 0;
+	struct usb_device *dev = interface_to_usbdev(interface);
 
 	if (HIF_USBDeviceInserted(interface, sc)) {
 		pr_err("ath: %s: Target probe failed.\n", __func__);
@@ -80,7 +92,7 @@ hif_usb_configure(struct hif_usb_softc *sc, hif_handle_t *hif_hdl,
 		pr_err("athdiag_procfs_init failed\n");
 		return A_ERROR;
 	}
-
+	hif_usb_unload_dev_num = dev->devnum;
 	*hif_hdl = sc->hif_device;
 	return 0;
 
@@ -125,7 +137,7 @@ hif_usb_probe(struct usb_interface *interface, const struct usb_device_id *id)
 		ret = -ENOMEM;
 		goto err_alloc;
 	}
-	usb_sc = sc;
+
 	OS_MEMZERO(sc, sizeof(*sc));
 	sc->pdev = (void *)pdev;
 	sc->dev = &pdev->dev;
@@ -179,7 +191,6 @@ hif_usb_probe(struct usb_interface *interface, const struct usb_device_id *id)
 	init_waitqueue_head(&ol_sc->sc_osdev->event_queue);
 
 	ret = hdd_wlan_startup(&pdev->dev, ol_sc);
-
 	if (ret) {
 		hif_nointrs(sc);
 		if (sc->hif_device != NULL) {
@@ -211,6 +222,8 @@ hif_usb_probe(struct usb_interface *interface, const struct usb_device_id *id)
 	sc->interface = interface;
 	sc->reboot_notifier.notifier_call = hif_usb_reboot;
 	register_reboot_notifier(&sc->reboot_notifier);
+
+	usb_sc = sc;
 	return 0;
 
 err_config:
@@ -218,7 +231,6 @@ err_config:
 err_attach:
 	ret = -EIO;
 err_tgtstate:
-	usb_sc = NULL;
 	A_FREE(sc);
 err_alloc:
 	usb_put_dev(pdev);
@@ -256,8 +268,11 @@ static void hif_usb_remove(struct usb_interface *interface)
 		usb_sc->local_state.event = 0;
 	}
 	unregister_reboot_notifier(&sc->reboot_notifier);
-
 	usb_put_dev(interface_to_usbdev(interface));
+	if (atomic_read(&hif_usb_unload_state) ==
+			HIF_USB_UNLOAD_STATE_DRV_DEREG)
+		atomic_set(&hif_usb_unload_state,
+			   HIF_USB_UNLOAD_STATE_TARGET_RESET);
 	scn = sc->ol_sc;
 
 	if (usb_sc->hdd_removed == 0) {
@@ -410,16 +425,47 @@ void hif_deinit_adf_ctx(void *ol_sc)
 	sc->adf_dev = NULL;
 }
 
+static int hif_usb_dev_notify(struct notifier_block *nb,
+				 unsigned long action, void *dev)
+{
+	struct usb_device *udev;
+	int ret = NOTIFY_DONE;
+
+	if (action != USB_DEVICE_REMOVE)
+		goto done;
+
+	udev = (struct usb_device *) dev;
+	if (hif_usb_unload_dev_num != udev->devnum)
+		goto done;
+
+	if (atomic_read(&hif_usb_unload_state) ==
+			HIF_USB_UNLOAD_STATE_TARGET_RESET) {
+		atomic_set(&hif_usb_unload_state,
+			   HIF_USB_UNLOAD_STATE_DEV_DISCONNECTED);
+		wake_up(&hif_usb_unload_event_wq);
+	}
+
+done:
+	return ret;
+}
+
+static struct notifier_block hif_usb_dev_nb = {
+	.notifier_call = hif_usb_dev_notify,
+};
 static int is_usb_driver_register = 0;
 int hif_register_driver(void)
 {
 	is_usb_driver_register = 1;
+	init_waitqueue_head(&hif_usb_unload_event_wq);
+	atomic_set(&hif_usb_unload_state, HIF_USB_UNLOAD_STATE_NULL);
+	usb_register_notify(&hif_usb_dev_nb);
 	return usb_register(&hif_usb_drv_id);
 }
 
 void hif_unregister_driver(void)
 {
 	if (is_usb_driver_register) {
+		long timeleft = 0;
 		if (usb_sc != NULL) {
 			/* wait __hdd_wlan_exit until finished and no more than
 			 * 4 seconds
@@ -449,7 +495,23 @@ void hif_unregister_driver(void)
 			}
 		}
 		is_usb_driver_register = 0;
+		atomic_set(&hif_usb_unload_state,
+			   HIF_USB_UNLOAD_STATE_DRV_DEREG);
 		usb_deregister(&hif_usb_drv_id);
+		if (atomic_read(&hif_usb_unload_state) !=
+				HIF_USB_UNLOAD_STATE_TARGET_RESET)
+			goto finish;
+		timeleft = wait_event_interruptible_timeout(
+				hif_usb_unload_event_wq,
+				atomic_read(&hif_usb_unload_state) ==
+				HIF_USB_UNLOAD_STATE_DEV_DISCONNECTED,
+				HIF_USB_UNLOAD_TIMEOUT);
+		if (timeleft <= 0)
+			pr_err("Fail to wait from DRV_DEREG to DISCONNECT,"
+				"timeleft = %ld \n\r",
+				timeleft);
+finish:
+		usb_unregister_notify(&hif_usb_dev_nb);
 	}
 }