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Jorgen Hansen authored
Use the DMA based receive operation instead of the ioread8_rep based datagram receive when DMA datagrams are supported. In the receive operation, configure the header to point to the page aligned VMCI_MAX_DG_SIZE part of the receive buffer using s/g configuration for the header. This ensures that the existing dispatch routine can be used with little modification. Initiate the receive by writing the lower 32 bit of the buffer to the VMCI_DATA_IN_LOW_ADDR register, and wait for the busy flag to be changed by the device using a wait queue. The existing dispatch routine for received datagrams is reused for the DMA datagrams with a few modifications: - the receive buffer is always the maximum size for DMA datagrams (IO ports would try with a shorter buffer first to reduce overhead of the ioread8_rep operation). - for DMA datagrams, datagrams are provided contiguous in the buffer as opposed to IO port datagrams, where they can start on any page boundary Reviewed-by:
Vishnu Dasa <vdasa@vmware.com> Signed-off-by:
Jorgen Hansen <jhansen@vmware.com> Link: https://lore.kernel.org/r/20220207102725.2742-9-jhansen@vmware.comSigned-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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