void (*free_buffer) (struct usb_ep *ep, void *buf, dma_addr_t dma,
unsigned bytes);
// NOTE: on 2.6, drivers may also use dma_map() and
// dma_sync_single_*() to directly manage dma overhead.
int (*queue) (struct usb_ep *ep, struct usb_request *req,
void (*free_buffer) (struct usb_ep *ep, void *buf, dma_addr_t dma,
unsigned bytes);
// NOTE: on 2.6, drivers may also use dma_map() and
// dma_sync_single_*() to directly manage dma overhead.
int (*queue) (struct usb_ep *ep, struct usb_request *req,