OpenCL Host Channel or Host Pipes

I attempting to implement a streaming or pseudo streaming interface between the host and device using the Intel A10 GX board, targeting the a10gx_hostch board in the a10_ref BSP supplied by Intel. I am using version 17.1.1.

I can find very little info on the host channel implementation. I was able to create a simple loopback kernel that reads from host_to_dev channel and writes back to the dev_to_host channel (the channels are described in the board_spec.xml). I can compile the .aocx without error using the aoc compiler and correctly targeting the a10gx_hostch BSP.

  <channels>
    <interface name="board" port="host_to_dev"  type="streamsource" width="256" chan_id="host_to_dev"/>
    <interface name="board" port="dev_to_host"  type="streamsink" width="256" chan_id="dev_to_host"/>
  </channels>

On the host side, I can find no support, examples, or documentation on reading/writing to these host channels. If I've missed it, I apologize. They are mentioned in Intel AN831. They are also mentioned in "Intel FPGA SDK for OpenCL Intel Arria10 GX FPGA Development Kit Reference Platform Porting Guide" - but only that they exist and how they are connected in the qsys design to a DMA.

I've found these threads that seem to use host channel / host pipe terms interchangeably .

• https://forums.intel.com/s/question/0D50P00003yyTdESAU/host-pipe-example-failed-set-arg-0-error-code-30 which seems to use "host pipe" and "host channel" interchangeably.
• https://forums.intel.com/s/question/0D50P00003yyTKHSA2/aoc-compile-error-using-host-channel-feature

The Intel design example for host pipes found at the link below does not mention host channels, but does say it requires a10ref_hostch.

https://www.intel.com/content/www/us/en/programmable/support/support-resources/design-examples/design-software/opencl/host-pipe.html

So a few questions:

1) Are host channels and host pipes the same thing??

2) If not, how do I read/write to host channels from the host? I hope it's not using low level DMA routines?

Any guidance or redirections to documents/white papers/reference designs is appreciated.

Thanks!