Merge branch 'net-ipa-hardware-pipeline-cleanup-fixes'

Merge branch 'net-ipa-hardware-pipeline-cleanup-fixes'

Alex Elder says:

====================
net: ipa: hardware pipeline cleanup fixes

There is a procedure currently referred to as a "tag process" that
is performed to clear the IPA hardware pipeline--either at the time
of a modem crash, or when suspending modem GSI channels.

One thing done in this procedure is issuing a command that sends a
data packet originating from the AP->command TX endpoint, destined
for the AP<-LAN RX (default) endpoint.  And although we currently
wait for the send to complete, we do *not* wait for the packet to be
received.  But the pipeline can't be assumed clear until we have
actually received this packet.

This series addresses this by detecting when the pipeline-clearing
packet has been received, and using a completion to allow a waiter
to know when that has happened.  This uses the IPA status capability
(which sends an extra status buffer for certain packets).  It also
uses the ability to supply a "tag" with a packet, which will be
delivered with the packet's status buffer.  We tag the data packet
that's sent to clear the pipeline, and use the receipt of a status
buffer associated with a tagged packet to determine when that packet
has arrived.

"Tag status" just desribes one aspect of this procedure, so some
symbols are renamed to be more like "pipeline clear" so they better
describe the larger purpose.  Finally, two functions used in this
code don't use their arguments, so those arguments are removed.
====================

Link: https://lore.kernel.org/r/20210126185703.29087-1-elder@linaro.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>