UDC should neither be started nor pulled up unless the gadget driver is bound. The new flag "allow_start" is now set by gadget_bind_driver() and cleared by gadget_unbind_driver(). usb_gadget_udc_start_locked() now checks whether allow_start is set before starting the UDC by invoking the ->udc_start() callback.
Fixes: fc274c1e9973 ("USB: gadget: Add a new bus for gadgets") Cc: stable stable@kernel.org Signed-off-by: Badhri Jagan Sridharan badhri@google.com --- v5 is the first version in this series. --- drivers/usb/gadget/udc/core.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c index 6ffe5fda8bb7..ac9d6186815d 100644 --- a/drivers/usb/gadget/udc/core.c +++ b/drivers/usb/gadget/udc/core.c @@ -37,6 +37,8 @@ static const struct bus_type gadget_bus_type; * @vbus: for udcs who care about vbus status, this value is real vbus status; * for udcs who do not care about vbus status, this value is always true * @started: the UDC's started state. True if the UDC had started. + * @allow_start: Indicates whether UDC is allowed to start. Set/cleared by gadget_(un)bind_driver() + * after gadget driver is bound or unbound. * @connect_lock: protects udc->vbus, udc->started, gadget->connect, gadget->deactivate related * functions. usb_gadget_connect_locked, usb_gadget_disconnect_locked, * usb_udc_connect_control_locked, usb_gadget_udc_start_locked, usb_gadget_udc_stop_locked are @@ -52,6 +54,7 @@ struct usb_udc { struct list_head list; bool vbus; bool started; + bool allow_start; struct work_struct vbus_work; struct mutex connect_lock; }; @@ -1204,6 +1207,9 @@ static inline int usb_gadget_udc_start_locked(struct usb_udc *udc) if (udc->started) { dev_err(&udc->dev, "UDC had already started\n"); return -EBUSY; + } else if (!udc->allow_start) { + dev_err(&udc->dev, "UDC not allowed to start. Is gadget driver bound ?\n"); + return -EIO; }
ret = udc->gadget->ops->udc_start(udc->gadget, udc->driver); @@ -1590,6 +1596,7 @@ static int gadget_bind_driver(struct device *dev) goto err_bind;
mutex_lock(&udc->connect_lock); + udc->allow_start = true; ret = usb_gadget_udc_start_locked(udc); if (ret) { mutex_unlock(&udc->connect_lock); @@ -1630,6 +1637,7 @@ static void gadget_unbind_driver(struct device *dev)
cancel_work_sync(&udc->vbus_work); mutex_lock(&udc->connect_lock); + udc->allow_start = false; usb_gadget_disconnect_locked(gadget); usb_gadget_disable_async_callbacks(udc); if (gadget->irq)