(Yes, the previous code temporarily broke EDMA TX. I'm sorry; I should've
actually setup ATH_BUF_FIFOEND on frames so txq->axq_fifo_depth was
cleared!)
This code implements a whole bunch of sorely needed EDMA TX improvements
along with CABQ TX support.
The specifics:
* When filling/refilling the FIFO, use the new TXQ staging queue
for FIFO frames
* Tag frames with ATH_BUF_FIFOPTR and ATH_BUF_FIFOEND correctly.
For now the non-CABQ transmit path pushes one frame into the TXQ
staging queue without setting up the intermediary link pointers
to chain them together, so draining frames from the txq staging
queue to the FIFO queue occurs AMPDU / MPDU at a time.
* In the CABQ case, manually tag the list with ATH_BUF_FIFOPTR and
ATH_BUF_FIFOEND so a chain of frames is pushed into the FIFO
at once.
* Now that frames are in a FIFO pending queue, we can top up the
FIFO after completing a single frame. This means we can keep
it filled rather than waiting for it drain and _then_ adding
more frames.
* The EDMA restart routine now walks the FIFO queue in the TXQ
rather than the pending queue and re-initialises the FIFO with
that.
* When restarting EDMA, we may have partially completed sending
a list. So stamp the first frame that we see in a list with
ATH_BUF_FIFOPTR and push _that_ into the hardware.
* When completing frames, only check those on the FIFO queue.
We should never ever queue frames from the pending queue
direct to the hardware, so there's no point in checking.
* Until I figure out what's going on, make sure if the TXSTATUS
for an empty queue pops up, complain loudly and continue.
This will stop the panics that people are seeing. I'll add
some code later which will assist in ensuring I'm populating
each descriptor with the correct queue ID.
* When considering whether to queue frames to the hardware queue
directly or software queue frames, make sure the depth of
the FIFO is taken into account now.
* When completing frames, tag them with ATH_BUF_BUSY if they're
not the final frame in a FIFO list. The same holding descriptor
behaviour is required when handling descriptors linked together
with a link pointer as the hardware will re-read the previous
descriptor to refresh the link pointer before contiuning.
* .. and if we complete the FIFO list (ie, the buffer has
ATH_BUF_FIFOEND set), then we don't need the holding buffer
any longer. Thus, free it.
Tested:
* AR9380/AR9580, STA and hostap
* AR9280, STA/hostap
TODO:
* I don't yet trust that the EDMA restart routine is totally correct
in all circumstances. I'll continue to thrash this out under heavy
multiple-TXQ traffic load and fix whatever pops up.
92e84e43a6