usb: cdnsp: Fix lack of spin_lock_irqsave/spin_lock_restore

Patch puts content of cdnsp_gadget_pullup function inside
spin_lock_irqsave and spin_lock_restore section.
This construction is required here to keep the data consistency,
otherwise some data can be changed e.g. from interrupt context.

Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
Reported-by: Ken (Jian) He <jianhe@ambarella.com>
cc: <stable@vger.kernel.org>
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
--

Changelog:
v2:
- added disable_irq/enable_irq as sugester by Peter Chen

drivers/usb/cdns3/cdnsp-gadget.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

Reviewed-by: Peter Chen <peter.chen@kernel.org>
Link: https://lore.kernel.org/r/20211214045527.26823-1-pawell@gli-login.cadence.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/cdns3/cdnsp-gadget.c b/drivers/usb/cdns3/cdnsp-gadget.c
index 27df0c6..e85bf76 100644 (file)
--- a/drivers/usb/cdns3/cdnsp-gadget.c
+++ b/drivers/usb/cdns3/cdnsp-gadget.c
@@ -1541,15 +1541,27 @@ static int cdnsp_gadget_pullup(struct usb_gadget *gadget, int is_on)
 {
        struct cdnsp_device *pdev = gadget_to_cdnsp(gadget);
        struct cdns *cdns = dev_get_drvdata(pdev->dev);
+       unsigned long flags;
 
        trace_cdnsp_pullup(is_on);
 
+       /*
+        * Disable events handling while controller is being
+        * enabled/disabled.
+        */
+       disable_irq(cdns->dev_irq);
+       spin_lock_irqsave(&pdev->lock, flags);
+
        if (!is_on) {
                cdnsp_reset_device(pdev);
                cdns_clear_vbus(cdns);
        } else {
                cdns_set_vbus(cdns);
        }
+
+       spin_unlock_irqrestore(&pdev->lock, flags);
+       enable_irq(cdns->dev_irq);
+
        return 0;
 }