On 5/14/2020 11:48 PM, Vinod Koul wrote:
On 13-05-20, 09:35, Dave Jiang wrote:
On 5/13/2020 12:30 AM, Peter Ujfalusi wrote:
On 12/05/2020 2.47, Dave Jiang wrote:
The cookie tracking in dmaengine expects all submissions completed in
order. Some DMA devices like Intel DSA can complete submissions out of
order, especially if configured with a work queue sharing multiple DMA
engines. Add a status DMA_OUT_OF_ORDER that tx_status can be returned for
those DMA devices. The user should use callbacks to track the completion
rather than the DMA cookie. This would address the issue of dmatest
complaining that descriptors are "busy" when the cookie count goes
backwards due to out of order completion. Add DMA_COMPLETION_NO_ORDER
DMA capability to allow the driver to flag the device's ability to complete
operations out of order.
I'm still a bit hesitant around this.
If the DMA only support out of order completion then it is mandatory
that each descriptor must have unique callback parameter in order the
client could know which transfer has been completed.
Maybe we can still use the cookie to indicate that, or leave it to users
to manage? They can add an id in the callback params?
Using former is easy, but still user needs to keep track... later can be
possibly more suited here?
Is there anything else I need to do with this patch?
