wusb: whci-hcd shouldn't do ASL/PZL updates while channel is inactive

ASL/PZL updates while the WUSB channel is inactive (i.e., the PZL and
ASL are stopped) may not complete.  This causes hangs when removing the
whci-hcd module if a device is still connected (removing the device
does an endpoint_disable which results in an ASL update to remove the
qset).

If the WUSB channel is inactive the update can simply be skipped as the
WHC doesn't care about the state of the ASL/PZL.

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

1 files changed, 18 insertions, 3 deletions

diff --git a/drivers/usb/host/whci/asl.c b/drivers/usb/host/whci/asl.c
index 4d7078e50572..ba99a7a3f81a 100644
--- a/drivers/usb/host/whci/asl.c
+++ b/drivers/usb/host/whci/asl.c
@@ -179,11 +179,26 @@ void asl_stop(struct whc *whc)
 		      1000, "stop ASL");
 }
 
+/**
+ * asl_update - request an ASL update and wait for the hardware to be synced
+ * @whc: the WHCI HC
+ * @wusbcmd: WUSBCMD value to start the update.
+ *
+ * If the WUSB HC is inactive (i.e., the ASL is stopped) then the
+ * update must be skipped as the hardware may not respond to update
+ * requests.
+ */
 void asl_update(struct whc *whc, uint32_t wusbcmd)
 {
-	whc_write_wusbcmd(whc, wusbcmd, wusbcmd);
-	wait_event(whc->async_list_wq,
-		   (le_readl(whc->base + WUSBCMD) & WUSBCMD_ASYNC_UPDATED) == 0);
+	struct wusbhc *wusbhc = &whc->wusbhc;
+
+	mutex_lock(&wusbhc->mutex);
+	if (wusbhc->active) {
+		whc_write_wusbcmd(whc, wusbcmd, wusbcmd);
+		wait_event(whc->async_list_wq,
+			   (le_readl(whc->base + WUSBCMD) & WUSBCMD_ASYNC_UPDATED) == 0);
+	}
+	mutex_unlock(&wusbhc->mutex);
 }
 
 /**