USB_BUFFER_MAP(9)                         USB Core APIs                         USB_BUFFER_MAP(9)



NAME
       usb_buffer_map - create DMA mapping(s) for an urb

SYNOPSIS
       struct urb * usb_buffer_map(struct urb * urb);

ARGUMENTS
       urb
           urb whose transfer_buffer/setup_packet will be mapped

DESCRIPTION
       URB_NO_TRANSFER_DMA_MAP is added to urb->transfer_flags if the operation succeeds. If the
       device is connected to this system through a non-DMA controller, this operation always
       succeeds.

       This call would normally be used for an urb which is reused, perhaps as the target of a
       large periodic transfer, with usb_buffer_dmasync calls to synchronize memory and dma
       state.

       Reverse the effect of this call with usb_buffer_unmap.

RETURN
       Either NULL (indicating no buffer could be mapped), or urb.

COPYRIGHT
Kernel Hackers Manual 4.8.                 January 2017                         USB_BUFFER_MAP(9)