- void usb_free_coherent(struct usb_device * dev, size_t size, void * addr, dma_addr_t dma);
- device the buffer was used with
- requested buffer size
- CPU address of buffer
- DMA address of buffer
This reclaims an I/O buffer, letting it be reused. The memory must have been allocated using usb_alloc_coherent, and the parameters must match those provided in that allocation request.