It turns out the frame scheduling policies (eg DBA_GATED) operate on
a single TX FIFO entry. ASAP scheduling is fine; those frames always
go out.
DBA-gated sets the TX queue ready when the DBA timer fires, which triggers
a beacon transmit. Normally this is used for content-after-beacon queue
(CABQ) work, which needs to burst out immediately after a beacon.
(eg broadcast, multicast, etc frames.) This is a general policy that you
can use for any queue, and Sam's TDMA code uses it.
When DBA_GATED is used and something like say, an 11e TX burst window,
it only operates on a single TX FIFO entry. If you have a single frame
per TX FIFO entry and say, a 2.5ms long burst window (eg TDMA!) then it'll
only burst a single frame every 2.5ms. If there's no gating (eg ASAP) then
the burst window is fine, and multiple TX FIFO slots get used.
The CABQ code does pack in a list of frames (ie, the whole cabq) but
up until this commit, the normal TX queues didn't. It showed up when
I started to debug TDMA on the AR9380 and later.
This commit doesn't fix the TDMA case - that's still broken here, because
all I'm doing here is allowing 'some' frames to be bursting, but I'm
certainly not filling the whole TX FIFO slot entry with frames.
Doing that 'properly' kind of requires me to take into account how long
packets should take to transmit and say, doing 1.5 or something times that
per TX FIFO slot, as if you partially transmit a slot, when it's next
gated it'll just finish that TX FIFO slot, then not advance to the next
one.
Now, I /also/ think queuing a new packet restarts DMA, but you have to
push new frames into the TX FIFO. I need to experiment some more with
this because if it's really the case, I will be able to do TDMA support
without the egregious hacks I have in my local tree. Sam's TDMA code
for previous chips would just kick the TXE bit to push along DMA
again, but we can't do that for EDMA chips - we /have/ to push a new
frame into the TX FIFO to restart DMA. Ugh.
Tested:
* AR9380, STA mode
* AR9380, hostap mode
* AR9580, hostap mode
Approved by: re (gjb)
49236b4e99