Due to some UDC controllers may not support stalling, usb gadget layer
needs to provide a generic way to inform gadget functions about non-standard
hardware limitations.
This patch adds 'quirk_stall_not_supp' field to struct usb_gadget and helper
function gadget_is_stall_supported(). It also sets 'quirk_stall_not_supp'
to 1 in at91_udc driver, which has such limitation.
Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
 
        INIT_LIST_HEAD(&udc->gadget.ep_list);
        INIT_LIST_HEAD(&udc->gadget.ep0->ep_list);
+       udc->gadget.quirk_stall_not_supp = 1;
 
        for (i = 0; i < NUM_ENDPOINTS; i++) {
                struct at91_ep *ep = &udc->ep[i];
 
        unsigned                        a_alt_hnp_support:1;
        unsigned                        quirk_ep_out_aligned_size:1;
        unsigned                        quirk_altset_not_supp:1;
+       unsigned                        quirk_stall_not_supp:1;
        unsigned                        is_selfpowered:1;
        unsigned                        deactivated:1;
        unsigned                        connected:1;
        return !g->quirk_altset_not_supp;
 }
 
+/**
+ * gadget_is_stall_supported - return true iff the hardware supports stalling
+ * @g: controller to check for quirk
+ */
+static inline int gadget_is_stall_supported(struct usb_gadget *g)
+{
+       return !g->quirk_stall_not_supp;
+}
+
 /**
  * gadget_is_dualspeed - return true iff the hardware handles high speed
  * @g: controller that might support both high and full speeds