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>

8 files changed, 155 insertions, 42 deletions

diff --git a/drivers/uwb/hwa-rc.c b/drivers/uwb/hwa-rc.c
index 18009c99577d..158e98d08af9 100644
--- a/drivers/uwb/hwa-rc.c
+++ b/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)
diff --git a/drivers/uwb/reset.c b/drivers/uwb/reset.c
index 8de856fa7958..e39b32099af3 100644
--- a/drivers/uwb/reset.c
+++ b/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);
diff --git a/drivers/uwb/rsv.c b/drivers/uwb/rsv.c
index ce0094657d3d..3d76efe26acc 100644
--- a/drivers/uwb/rsv.c
+++ b/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);
 }
diff --git a/drivers/uwb/umc-bus.c b/drivers/uwb/umc-bus.c
index 2d8d62d9f53e..5ad36164c13b 100644
--- a/drivers/uwb/umc-bus.c
+++ b/drivers/uwb/umc-bus.c
@@ -11,23 +11,48 @@
 #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.
@@ -35,14 +60,13 @@ static int umc_bus_unbind_helper(struct device *dev, void *data)
 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;
@@ -75,10 +99,10 @@ 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;
 
@@ -86,7 +110,7 @@ static void umc_bus_rescan(void)
          * 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;
 }
diff --git a/drivers/uwb/uwb-internal.h b/drivers/uwb/uwb-internal.h
index 4c2449679978..af95541dabcd 100644
--- a/drivers/uwb/uwb-internal.h
+++ b/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);
diff --git a/drivers/uwb/whc-rc.c b/drivers/uwb/whc-rc.c
index 6c454eadd307..e0d66938ccd8 100644
--- a/drivers/uwb/whc-rc.c
+++ b/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)
diff --git a/include/linux/uwb.h b/include/linux/uwb.h
index 881f0c5b6d28..c4854848999d 100644
--- a/include/linux/uwb.h
+++ b/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?
diff --git a/include/linux/uwb/umc.h b/include/linux/uwb/umc.h
index 36a39e34f8d7..4b4fc0f43855 100644
--- a/include/linux/uwb/umc.h
+++ b/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;
 };