[PATCH 06/19] usb: gadget: snps_udc_plat: lock out the interrupt

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Josef Bacik <josef@toxicpanda.com>

stop_udc() is called from a work item, when the extcon device reports
that the cable has been unplugged.  It takes udc->lock with interrupts
enabled.  udc_irq(), the hard interrupt handler of the controller, takes
the same lock.  If the controller raises an interrupt on the CPU which
is in stop_udc(), and it is likely to have something to report when the
cable is pulled, the handler spins on a lock which the interrupted work
holds: the CPU is stuck.

Disable interrupts while the lock is held.  They are enabled again for
the ->disconnect() callback of the gadget driver, for which the lock is
dropped as before.

Fixes: 1b9f35adb0ff ("usb: gadget: udc: Add Synopsys UDC Platform driver")
Cc: stable <stable@kernel.org>
Cc: Neill Kapron <nkapron@google.com>
Cc: Ijae Kim <ae878000@gmail.com>
Cc: Herve Codina <herve.codina@bootlin.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/gadget/udc/snps_udc_plat.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/gadget/udc/snps_udc_plat.c b/drivers/usb/gadget/udc/snps_udc_plat.c
index 8ce43c4f8fba..e2e71cc947dc 100644
--- a/drivers/usb/gadget/udc/snps_udc_plat.c
+++ b/drivers/usb/gadget/udc/snps_udc_plat.c
@@ -34,7 +34,7 @@ static void stop_udc(struct udc *udc)
 	int tmp;
 	u32 reg;
 
-	spin_lock(&udc->lock);
+	spin_lock_irq(&udc->lock);
 
 	/* Flush the receieve fifo */
 	reg = readl(&udc->regs->ctl);
@@ -53,9 +53,9 @@ static void stop_udc(struct udc *udc)
 
 	/* Disconnect gadget driver */
 	if (udc->driver) {
-		spin_unlock(&udc->lock);
+		spin_unlock_irq(&udc->lock);
 		udc->driver->disconnect(&udc->gadget);
-		spin_lock(&udc->lock);
+		spin_lock_irq(&udc->lock);
 
 		/* empty queues */
 		for (tmp = 0; tmp < UDC_EP_NUM; tmp++)
@@ -63,7 +63,7 @@ static void stop_udc(struct udc *udc)
 	}
 	udc->connected = 0;
 
-	spin_unlock(&udc->lock);
+	spin_unlock_irq(&udc->lock);
 	dev_info(udc->dev, "Device disconnected\n");
 }
 

-- 
2.56.0