dau_driver.transfer
===================

.. py:module:: dau_driver.transfer


Classes
-------

.. autoapisummary::

   dau_driver.transfer.DmaDirection
   dau_driver.transfer.DmaTransfer


Functions
---------

.. autoapisummary::

   dau_driver.transfer.validate_transfer


Module Contents
---------------

.. py:class:: DmaDirection

   Bases: :py:obj:`enum.StrEnum`


   Enum where members are also (and must be) strings

   Initialize self.  See help(type(self)) for accurate signature.


   .. py:attribute:: H2C
      :value: 'h2c'



   .. py:attribute:: C2H
      :value: 'c2h'



.. py:class:: DmaTransfer

   .. py:attribute:: direction
      :type:  DmaDirection


   .. py:attribute:: device_address
      :type:  int


   .. py:attribute:: byte_count
      :type:  int


   .. py:attribute:: channel_path
      :type:  pathlib.Path


.. py:function:: validate_transfer(direction: DmaDirection, device_address: int, byte_count: int, constraints: dau_core.capabilities.DmaConstraints, *, memory_bytes: int | None = None) -> None

   Refuse a transfer the device cannot perform as asked.

   ``memory_bytes`` is the device's addressable memory when the caller knows
   it; with it, the whole span ``[device_address, device_address + byte_count)``
   must lie inside memory, since the DMA engine wraps an address past the end
   to the bottom of memory instead of failing.