uwb: avoid radio controller reset loops

If a radio controller reset attempt occurs while a probe() or remove()
is in progress it fails and is retried endlessly, potentially preventing
the probe() or remove() from completing.

If a reset fails, sleep for a bit before retrying the reset.  This
allows the probe()/remove() to complete.

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

4 files changed, 14 insertions, 15 deletions

diff --git a/drivers/uwb/hwa-rc.c b/drivers/uwb/hwa-rc.c
index 9052bcb4f528..e7eeb63fab23 100644
--- a/drivers/uwb/hwa-rc.c
+++ b/drivers/uwb/hwa-rc.c
@@ -887,8 +887,7 @@ 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;
+        return uwb_rc_post_reset(uwb_rc);
 }
 
 /** USB device ID's that we handle */
diff --git a/drivers/uwb/reset.c b/drivers/uwb/reset.c
index 70f8050221ff..7f0512e43d9d 100644
--- a/drivers/uwb/reset.c
+++ b/drivers/uwb/reset.c
@@ -30,6 +30,7 @@
  */
 #include <linux/kernel.h>
 #include <linux/err.h>
+#include <linux/delay.h>
 
 #include "uwb-internal.h"
 
@@ -323,13 +324,15 @@ int uwbd_msg_handle_reset(struct uwb_event *evt)
 
         dev_info(&rc->uwb_dev.dev, "resetting radio controller\n");
         ret = rc->reset(rc);
-        if (ret) {
+        if (ret < 0) {
                 dev_err(&rc->uwb_dev.dev, "failed to reset hardware: %d\n", ret);
                 goto error;
         }
         return 0;
 error:
-        /* Nothing can be done except try the reset again. */
+        /* Nothing can be done except try the reset again. Wait a bit
+           to avoid reset loops during probe() or remove(). */
+        msleep(1000);
         uwb_rc_reset_all(rc);
         return ret;
 }
@@ -368,22 +371,20 @@ void uwb_rc_pre_reset(struct uwb_rc *rc)
 }
 EXPORT_SYMBOL_GPL(uwb_rc_pre_reset);
 
-void uwb_rc_post_reset(struct uwb_rc *rc)
+int uwb_rc_post_reset(struct uwb_rc *rc)
 {
         int ret;
 
         ret = rc->start(rc);
         if (ret)
-                goto error;
+                goto out;
         ret = uwb_rc_mac_addr_set(rc, &rc->uwb_dev.mac_addr);
         if (ret)
-                goto error;
+                goto out;
         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);
+                goto out;
+out:
+        return ret;
 }
 EXPORT_SYMBOL_GPL(uwb_rc_post_reset);
diff --git a/drivers/uwb/umc-bus.c b/drivers/uwb/umc-bus.c
index 5ad36164c13b..cdd6c8efc9f8 100644
--- a/drivers/uwb/umc-bus.c
+++ b/drivers/uwb/umc-bus.c
@@ -66,7 +66,7 @@ int umc_controller_reset(struct umc_dev *umc)
                 return -EAGAIN;
         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);
+                ret = device_for_each_child(parent, parent, umc_bus_post_reset_helper);
         up(&parent->sem);
 
         return ret;
diff --git a/drivers/uwb/whc-rc.c b/drivers/uwb/whc-rc.c
index 19a1dd129212..1d9a6f54658e 100644
--- a/drivers/uwb/whc-rc.c
+++ b/drivers/uwb/whc-rc.c
@@ -443,8 +443,7 @@ 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;
+        return uwb_rc_post_reset(uwb_rc);
 }
 
 /* PCI device ID's that we handle [so it gets loaded] */