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>

4 files changed, 72 insertions, 31 deletions

diff --git a/drivers/usb/host/whci/asl.c b/drivers/usb/host/whci/asl.c
index 4d7078e5..ba99a7a 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);
 }
 
 /**
diff --git a/drivers/usb/host/whci/pzl.c b/drivers/usb/host/whci/pzl.c
index 8d62df0..34d3a0a 100644
--- a/drivers/usb/host/whci/pzl.c
+++ b/drivers/usb/host/whci/pzl.c
@@ -195,11 +195,26 @@ void pzl_stop(struct whc *whc)
 		      1000, "stop PZL");
 }
 
+/**
+ * pzl_update - request a PZL 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 PZL is stopped) then the
+ * update must be skipped as the hardware may not respond to update
+ * requests.
+ */
 void pzl_update(struct whc *whc, uint32_t wusbcmd)
 {
-	whc_write_wusbcmd(whc, wusbcmd, wusbcmd);
-	wait_event(whc->periodic_list_wq,
-		   (le_readl(whc->base + WUSBCMD) & WUSBCMD_PERIODIC_UPDATED) == 0);
+	struct wusbhc *wusbhc = &whc->wusbhc;
+
+	mutex_lock(&wusbhc->mutex);
+	if (wusbhc->active) {
+		whc_write_wusbcmd(whc, wusbcmd, wusbcmd);
+		wait_event(whc->periodic_list_wq,
+			   (le_readl(whc->base + WUSBCMD) & WUSBCMD_PERIODIC_UPDATED) == 0);
+	}
+	mutex_unlock(&wusbhc->mutex);
 }
 
 static void update_pzl_hw_view(struct whc *whc)
diff --git a/drivers/usb/wusbcore/devconnect.c b/drivers/usb/wusbcore/devconnect.c
index 08a1ec9..26cbc89 100644
--- a/drivers/usb/wusbcore/devconnect.c
+++ b/drivers/usb/wusbcore/devconnect.c
@@ -484,21 +484,15 @@ static void __wusbhc_keep_alive(struct wusbhc *wusbhc)
  */
 static void wusbhc_keep_alive_run(struct work_struct *ws)
 {
-	struct delayed_work *dw =
-		container_of(ws, struct delayed_work, work);
-	struct wusbhc *wusbhc =
-		container_of(dw, struct wusbhc, keep_alive_timer);
-
-	d_fnstart(5, wusbhc->dev, "(wusbhc %p)\n", wusbhc);
-	if (wusbhc->active) {
-		mutex_lock(&wusbhc->mutex);
-		__wusbhc_keep_alive(wusbhc);
-		mutex_unlock(&wusbhc->mutex);
-		queue_delayed_work(wusbd, &wusbhc->keep_alive_timer,
-				   (wusbhc->trust_timeout * CONFIG_HZ)/1000/2);
-	}
-	d_fnend(5, wusbhc->dev, "(wusbhc %p) = void\n", wusbhc);
-	return;
+	struct delayed_work *dw = container_of(ws, struct delayed_work, work);
+	struct wusbhc *wusbhc =	container_of(dw, struct wusbhc, keep_alive_timer);
+
+	mutex_lock(&wusbhc->mutex);
+	__wusbhc_keep_alive(wusbhc);
+	mutex_unlock(&wusbhc->mutex);
+
+	queue_delayed_work(wusbd, &wusbhc->keep_alive_timer,
+			   msecs_to_jiffies(wusbhc->trust_timeout / 2));
 }
 
 /*
diff --git a/drivers/usb/wusbcore/mmc.c b/drivers/usb/wusbcore/mmc.c
index 5463ece..3b52161 100644
--- a/drivers/usb/wusbcore/mmc.c
+++ b/drivers/usb/wusbcore/mmc.c
@@ -159,6 +159,27 @@ found:
 }
 EXPORT_SYMBOL_GPL(wusbhc_mmcie_rm);
 
+static int wusbhc_mmc_start(struct wusbhc *wusbhc)
+{
+	int ret;
+
+	mutex_lock(&wusbhc->mutex);
+	ret = wusbhc->start(wusbhc);
+	if (ret >= 0)
+		wusbhc->active = 1;
+	mutex_unlock(&wusbhc->mutex);
+
+	return ret;
+}
+
+static void wusbhc_mmc_stop(struct wusbhc *wusbhc)
+{
+	mutex_lock(&wusbhc->mutex);
+	wusbhc->active = 0;
+	wusbhc->stop(wusbhc, WUSB_CHANNEL_STOP_DELAY_MS);
+	mutex_unlock(&wusbhc->mutex);
+}
+
 /*
  * wusbhc_start - start transmitting MMCs and accepting connections
  * @wusbhc: the HC to start
@@ -198,12 +219,12 @@ int wusbhc_start(struct wusbhc *wusbhc)
 		dev_err(dev, "Cannot set DNTS parameters: %d\n", result);
 		goto error_set_num_dnts;
 	}
-	result = wusbhc->start(wusbhc);
+	result = wusbhc_mmc_start(wusbhc);
 	if (result < 0) {
 		dev_err(dev, "error starting wusbch: %d\n", result);
 		goto error_wusbhc_start;
 	}
-	wusbhc->active = 1;
+
 	return 0;
 
 error_wusbhc_start:
@@ -225,15 +246,11 @@ error_rsv_establish:
  */
 void wusbhc_stop(struct wusbhc *wusbhc)
 {
-	if (wusbhc->active) {
-		wusbhc->active = 0;
-		wusbhc->stop(wusbhc, WUSB_CHANNEL_STOP_DELAY_MS);
-		wusbhc_sec_stop(wusbhc);
-		wusbhc_devconnect_stop(wusbhc);
-		wusbhc_rsv_terminate(wusbhc);
-	}
+	wusbhc_mmc_stop(wusbhc);
+	wusbhc_sec_stop(wusbhc);
+	wusbhc_devconnect_stop(wusbhc);
+	wusbhc_rsv_terminate(wusbhc);
 }
-EXPORT_SYMBOL_GPL(wusbhc_stop);
 
 /*
  * Set/reset/update a new CHID