Hi Sinan,

On Thu, Feb 04, 2016 at 11:34:31PM -0500, Sinan Kaya wrote:

The Qualcomm Technologies HIDMA device has been designed
to support virtualization technology. The driver has been
divided into two to follow the hardware design.

1. HIDMA Management driver
2. HIDMA Channel driver

Each HIDMA HW consists of multiple channels. These channels
share some set of common parameters. These parameters are
initialized by the management driver during power up.
Same management driver is used for monitoring the execution
of the channels. Management driver can change the performance
behavior dynamically such as bandwidth allocation and
prioritization in the future.

The management driver is executed in host context and
is the main management entity for all channels provided by
the device.

I'm not at all familiar with this kind of hardware.

Once an entity (userspace or VM) has a HIDAM channel assigned via VFIO,
how does it use it?  Is it used in relation with another device to
perform DMA on its behalf or is a HIDMA channel something that's useful
on its own?

Thanks,
-Christoffer