uwb: don't unbind the radio controller driver when resetting

Use pre_reset and post_reset methods to avoid unbinding the radio
controller driver after a uwb_rc_reset_all() call.  This avoids a
deadlock in uwb_rc_rm() when waiting for the uwb event thread to stop.

Signed-off-by: David Vrabel <david.vrabel@csr.com>

drivers/uwb/hwa-rc.c

@@ -881,6 +881,24 @@ static void hwarc_disconnect(struct usb_interface *iface)
 	uwb_rc_put(uwb_rc);	/* when creating the device, refcount = 1 */
 }
 
+static int hwarc_pre_reset(struct usb_interface *iface)
+{
+	struct hwarc *hwarc = usb_get_intfdata(iface);
+	struct uwb_rc *uwb_rc = hwarc->uwb_rc;
+
+	uwb_rc_pre_reset(uwb_rc);
+	return 0;
+}
+
+static int hwarc_post_reset(struct usb_interface *iface)
+{
+	struct hwarc *hwarc = usb_get_intfdata(iface);
+	struct uwb_rc *uwb_rc = hwarc->uwb_rc;
+
+	uwb_rc_post_reset(uwb_rc);
+	return 0;
+}
+
 /** USB device ID's that we handle */
 static struct usb_device_id hwarc_id_table[] = {
 	/* D-Link DUB-1210 */
@@ -897,9 +915,11 @@ MODULE_DEVICE_TABLE(usb, hwarc_id_table);
 
 static struct usb_driver hwarc_driver = {
 	.name =		"hwa-rc",
+	.id_table =	hwarc_id_table,
 	.probe =	hwarc_probe,
 	.disconnect =	hwarc_disconnect,
-	.id_table =	hwarc_id_table,
+	.pre_reset =    hwarc_pre_reset,
+	.post_reset =   hwarc_post_reset,
 };
 
 static int __init hwarc_driver_init(void)

drivers/uwb/reset.c

@@ -323,17 +323,16 @@ int uwbd_msg_handle_reset(struct uwb_event *evt)
 	struct uwb_rc *rc = evt->rc;
 	int ret;
 
-	/* Need to prevent the RC hardware module going away while in
-	   the rc->reset() call. */
-	if (!try_module_get(rc->owner))
-		return 0;
-
 	dev_info(&rc->uwb_dev.dev, "resetting radio controller\n");
 	ret = rc->reset(rc);
-	if (ret)
+	if (ret) {
 		dev_err(&rc->uwb_dev.dev, "failed to reset hardware: %d\n", ret);
-
-	module_put(rc->owner);
+		goto error;
+	}
+	return 0;
+error:
+	/* Nothing can be done except try the reset again. */
+	uwb_rc_reset_all(rc);
 	return ret;
 }
 
@@ -360,3 +359,37 @@ void uwb_rc_reset_all(struct uwb_rc *rc)
 	uwbd_event_queue(evt);
 }
 EXPORT_SYMBOL_GPL(uwb_rc_reset_all);
+
+void uwb_rc_pre_reset(struct uwb_rc *rc)
+{
+	rc->stop(rc);
+	uwbd_flush(rc);
+
+	mutex_lock(&rc->uwb_dev.mutex);
+	rc->beaconing = -1;
+	rc->scanning = -1;
+	mutex_unlock(&rc->uwb_dev.mutex);
+
+	uwb_rsv_remove_all(rc);
+}
+EXPORT_SYMBOL_GPL(uwb_rc_pre_reset);
+
+void uwb_rc_post_reset(struct uwb_rc *rc)
+{
+	int ret;
+
+	ret = rc->start(rc);
+	if (ret)
+		goto error;
+	ret = uwb_rc_mac_addr_set(rc, &rc->uwb_dev.mac_addr);
+	if (ret)
+		goto error;
+	ret = uwb_rc_dev_addr_set(rc, &rc->uwb_dev.dev_addr);
+	if (ret)
+		goto error;
+	return;
+error:
+	/* Nothing can be done except try the reset again. */
+	uwb_rc_reset_all(rc);
+}
+EXPORT_SYMBOL_GPL(uwb_rc_post_reset);

drivers/uwb/rsv.c

@@ -659,6 +659,25 @@ static void uwb_rsv_timer(unsigned long arg)
 	uwb_rsv_sched_update(rsv->rc);
 }
 
+/**
+ * uwb_rsv_remove_all - remove all reservations
+ * @rc: the radio controller
+ *
+ * A DRP IE update is not done.
+ */
+void uwb_rsv_remove_all(struct uwb_rc *rc)
+{
+	struct uwb_rsv *rsv, *t;
+
+	mutex_lock(&rc->rsvs_mutex);
+	list_for_each_entry_safe(rsv, t, &rc->reservations, rc_node) {
+		uwb_rsv_remove(rsv);
+	}
+	mutex_unlock(&rc->rsvs_mutex);
+
+	cancel_work_sync(&rc->rsv_update_work);
+}
+
 void uwb_rsv_init(struct uwb_rc *rc)
 {
 	INIT_LIST_HEAD(&rc->reservations);
@@ -682,14 +701,6 @@ int uwb_rsv_setup(struct uwb_rc *rc)
 
 void uwb_rsv_cleanup(struct uwb_rc *rc)
 {
-	struct uwb_rsv *rsv, *t;
-
-	mutex_lock(&rc->rsvs_mutex);
-	list_for_each_entry_safe(rsv, t, &rc->reservations, rc_node) {
-		uwb_rsv_remove(rsv);
-	}
-	mutex_unlock(&rc->rsvs_mutex);
-
-	cancel_work_sync(&rc->rsv_update_work);
+	uwb_rsv_remove_all(rc);
 	destroy_workqueue(rc->rsv_workq);
 }

drivers/uwb/umc-bus.c

@@ -11,38 +11,62 @@
 #include <linux/uwb/umc.h>
 #include <linux/pci.h>
 
-static int umc_bus_unbind_helper(struct device *dev, void *data)
+static int umc_bus_pre_reset_helper(struct device *dev, void *data)
 {
-	struct device *parent = data;
+	int ret = 0;
 
-	if (dev->parent == parent && dev->driver)
-		device_release_driver(dev);
-	return 0;
+	if (dev->driver) {
+		struct umc_dev *umc = to_umc_dev(dev);
+		struct umc_driver *umc_drv = to_umc_driver(dev->driver);
+
+		if (umc_drv->pre_reset)
+			ret = umc_drv->pre_reset(umc);
+		else
+			device_release_driver(dev);
+	}
+	return ret;
+}
+
+static int umc_bus_post_reset_helper(struct device *dev, void *data)
+{
+	int ret = 0;
+
+	if (dev->driver) {
+		struct umc_dev *umc = to_umc_dev(dev);
+		struct umc_driver *umc_drv = to_umc_driver(dev->driver);
+
+		if (umc_drv->post_reset)
+			ret = umc_drv->post_reset(umc);
+	} else
+		ret = device_attach(dev);
+
+	return ret;
 }
 
 /**
  * umc_controller_reset - reset the whole UMC controller
  * @umc: the UMC device for the radio controller.
  *
- * Drivers will be unbound from all UMC devices belonging to the
- * controller and then the radio controller will be rebound.  The
- * radio controller is expected to do a full hardware reset when it is
- * probed.
+ * Drivers or all capabilities of the controller will have their
+ * pre_reset methods called or be unbound from their device.  Then all
+ * post_reset methods will be called or the drivers will be rebound.
+ *
+ * Radio controllers must provide pre_reset and post_reset methods and
+ * reset the hardware in their start method.
  *
  * If this is called while a probe() or remove() is in progress it
  * will return -EAGAIN and not perform the reset.
  */
 int umc_controller_reset(struct umc_dev *umc)
 {
 	struct device *parent = umc->dev.parent;
-	int ret;
+	int ret = 0;
 
-	if (down_trylock(&parent->sem))
+	if(down_trylock(&parent->sem))
 		return -EAGAIN;
-	bus_for_each_dev(&umc_bus_type, NULL, parent, umc_bus_unbind_helper);
-	ret = device_attach(&umc->dev);
-	if (ret == 1)
-		ret = 0;
+	ret = device_for_each_child(parent, parent, umc_bus_pre_reset_helper);
+	if (ret >= 0)
+		device_for_each_child(parent, parent, umc_bus_post_reset_helper);
 	up(&parent->sem);
 
 	return ret;
@@ -75,18 +99,18 @@ static int umc_bus_rescan_helper(struct device *dev, void *data)
 	if (!dev->driver)
 		ret = device_attach(dev);
 
-	return ret < 0 ? ret : 0;
+	return ret;
 }
 
-static void umc_bus_rescan(void)
+static void umc_bus_rescan(struct device *parent)
 {
 	int err;
 
 	/*
 	 * We can't use bus_rescan_devices() here as it deadlocks when
 	 * it tries to retake the dev->parent semaphore.
 	 */
-	err = bus_for_each_dev(&umc_bus_type, NULL, NULL, umc_bus_rescan_helper);
+	err = device_for_each_child(parent, NULL, umc_bus_rescan_helper);
 	if (err < 0)
 		printk(KERN_WARNING "%s: rescan of bus failed: %d\n",
 		       KBUILD_MODNAME, err);
@@ -120,7 +144,7 @@ static int umc_device_probe(struct device *dev)
 	if (err)
 		put_device(dev);
 	else
-		umc_bus_rescan();
+		umc_bus_rescan(dev->parent);
 
 	return err;
 }

drivers/uwb/uwb-internal.h

@@ -248,6 +248,7 @@ extern struct device_attribute dev_attr_scan;
 void uwb_rsv_init(struct uwb_rc *rc);
 int uwb_rsv_setup(struct uwb_rc *rc);
 void uwb_rsv_cleanup(struct uwb_rc *rc);
+void uwb_rsv_remove_all(struct uwb_rc *rc);
 
 void uwb_rsv_set_state(struct uwb_rsv *rsv, enum uwb_rsv_state new_state);
 void uwb_rsv_remove(struct uwb_rsv *rsv);

drivers/uwb/whc-rc.c

@@ -394,7 +394,7 @@ void whcrc_stop_rc(struct uwb_rc *rc)
 
 	le_writel(0, whcrc->rc_base + URCCMD);
 	whci_wait_for(&umc_dev->dev, whcrc->rc_base + URCSTS,
-		      URCSTS_HALTED, 0, 40, "URCSTS.HALTED");
+		      URCSTS_HALTED, URCSTS_HALTED, 100, "URCSTS.HALTED");
 }
 
 static void whcrc_init(struct whcrc *whcrc)
@@ -488,6 +488,24 @@ static void whcrc_remove(struct umc_dev *umc_dev)
 	d_printf(1, &umc_dev->dev, "freed whcrc %p\n", whcrc);
 }
 
+static int whcrc_pre_reset(struct umc_dev *umc)
+{
+	struct whcrc *whcrc = umc_get_drvdata(umc);
+	struct uwb_rc *uwb_rc = whcrc->uwb_rc;
+
+	uwb_rc_pre_reset(uwb_rc);
+	return 0;
+}
+
+static int whcrc_post_reset(struct umc_dev *umc)
+{
+	struct whcrc *whcrc = umc_get_drvdata(umc);
+	struct uwb_rc *uwb_rc = whcrc->uwb_rc;
+
+	uwb_rc_post_reset(uwb_rc);
+	return 0;
+}
+
 /* PCI device ID's that we handle [so it gets loaded] */
 static struct pci_device_id whcrc_id_table[] = {
 	{ PCI_DEVICE_CLASS(PCI_CLASS_WIRELESS_WHCI, ~0) },
@@ -496,10 +514,12 @@ static struct pci_device_id whcrc_id_table[] = {
 MODULE_DEVICE_TABLE(pci, whcrc_id_table);
 
 static struct umc_driver whcrc_driver = {
-	.name   = "whc-rc",
-	.cap_id = UMC_CAP_ID_WHCI_RC,
-	.probe  = whcrc_probe,
-	.remove = whcrc_remove,
+	.name       = "whc-rc",
+	.cap_id     = UMC_CAP_ID_WHCI_RC,
+	.probe      = whcrc_probe,
+	.remove     = whcrc_remove,
+	.pre_reset  = whcrc_pre_reset,
+	.post_reset = whcrc_post_reset,
 };
 
 static int __init whcrc_driver_init(void)

include/linux/uwb.h

@@ -540,6 +540,8 @@ void uwb_rc_rm(struct uwb_rc *);
 void uwb_rc_neh_grok(struct uwb_rc *, void *, size_t);
 void uwb_rc_neh_error(struct uwb_rc *, int);
 void uwb_rc_reset_all(struct uwb_rc *rc);
+void uwb_rc_pre_reset(struct uwb_rc *rc);
+void uwb_rc_post_reset(struct uwb_rc *rc);
 
 /**
  * uwb_rsv_is_owner - is the owner of this reservation the RC?

include/linux/uwb/umc.h

@@ -89,6 +89,8 @@ struct umc_driver {
 	void (*remove)(struct umc_dev *);
 	int  (*suspend)(struct umc_dev *, pm_message_t state);
 	int  (*resume)(struct umc_dev *);
+	int  (*pre_reset)(struct umc_dev *);
+	int  (*post_reset)(struct umc_dev *);
 
 	struct device_driver driver;
 };