This occurs at RX DMA start, even though the RX FIFO has plenty of
space. I'll go figure out why, but this shouldn't cause people to
be spammed by these messages.
The AHB code:
* hard coded the AR9130 device id;
* assumes a 4k flash calibration space.
This code now extends this:
* hint.ath.X.eepromsize now overrides the eeprom range, instead of 4k
* hint.ath.X.device_id and hint.ath.X.vendor_id can now be overridden.
Tested:
* AR9330 board (Carambola 2)
This hasn't yet been tested as unfortunately the AR3012 I have doesn't
have the "real" firmware on it; it shipped with the cut down HCI firmware
that only understands enough to accept a new firmware image.
* Linux ath9k (GPIO constants)
* Add the LNA configuration table entries for AR933x/AR9485
* Add a chip-dependent LNA signal level delta in the startup path
* Add a TODO list for the stuff I haven't yet ported over but
I haven't.
Tested:
* AR9462 with LNA diversity enabled
The reference HAL pushes a config group parameter to the driver layer
to inform it which particular chip behaviour to implement.
This particular value tags it as an AR9285.
The AR9485 chip and AR933x SoC both implement LNA diversity.
There are a few extra things that need to happen before this can be
flipped on for those chips (mostly to do with setting up the different
bias values and LNA1/LNA2 RSSI differences) but the first stage is
putting this code into the driver layer so it can be reused.
This has the added benefit of making it easier to expose configuration
options and diagnostic information via the ioctl API. That's not yet
being done but it sure would be nice to do so.
Tested:
* AR9285, with LNA diversity enabled
* AR9285, with LNA diversity disabled in EEPROM
for the WB195 combo NIC - an AR9285 w/ an AR3011 USB bluetooth NIC.
The AR3011 is wired up using a 3-wire coexistence scheme to the AR9285.
The code in if_ath_btcoex.c sets up the initial hardware mapping
and coexistence configuration. There's nothing special about it -
it's static; it doesn't try to configure bluetooth / MAC traffic priorities
or try to figure out what's actually going on. It's enough to stop basic
bluetooth traffic from causing traffic stalls and diassociation from
the wireless network.
To use this code, you must have the above NIC. No, it won't work
for the AR9287+AR3012, nor the AR9485, AR9462 or AR955x combo cards.
Then you set a kernel hint before boot or before kldload, where 'X'
is the unit number of your AR9285 NIC:
# kenv hint.ath.X.btcoex_profile=wb195
This will then appear in your boot messages:
[100482] athX: Enabling WB195 BTCOEX
This code is going to evolve pretty quickly (well, depending upon my
spare time) so don't assume the btcoex API is going to stay stable.
In order to use the bluetooth side, you must also load in firmware using
ath3kfw and the binary firmware file (ath3k-1.fw in my case.)
Tested:
* AR9280, no interference
* WB195 - AR9285 + AR3011 combo; STA mode; basic bluetooth inquiries
were enough to cause traffic stalls and disassociations. This has
stopped with the btcoex profile code.
TODO:
* Importantly - the AR9285 needs ASPM disabled if bluetooth coexistence
is enabled. No, I don't know why. It's likely some kind of bug to do
with the AR3011 sending bluetooth coexistence signals whilst the device
is asleep. Since we don't actually sleep the MAC just yet, it shouldn't
be a problem. That said, to be totally correct:
+ ASPM should be disabled - upon attach and wakeup
+ The PCIe powersave HAL code should never be called
Look at what the ath9k driver does for inspiration.
* Add WB197 (AR9287+AR3012) support
* Add support for the AR9485, which is another combo like the AR9285
* The later NICs have a different signaling mechanism between the MAC
and the bluetooth device; I haven't even begun to experiment with
making that HAL code work. But it should be a lot more automatic.
* The hardware can do much more interesting traffic weighting with
bluetooth and wifi traffic. None of this is currently used.
Ideally someone would code up something to watch the bluetooth traffic
GPIO (via an interrupt) and then watch it go high/low; then figure out
what the bluetooth traffic is and adjust things appropriately.
* If I get the time I may add in some code to at least track this stuff
and expose statistics. But it's up to someone else to experiment with
the bluetooth coexistence support and add the interesting stuff (like
"real" detection of bulk, audio, etc bluetooth traffic patterns and
change wifi parameters appropriately - eg, maximum aggregate length,
transmit power, using quiet time to control TX duty cycle, etc.)
* Call the bluetooth setup function during the reset path, so the bluetooth
settings are actually initialised.
* Call the AR9285 diversity functions during bluetooth setup; so the AR9285
diversity and antenna configuration registers are correctly programmed
* Misc debugging info.
Tested:
* AR9285+AR3011 bluetooth combo; this code itself doesn't enable bluetooth
coexistence but it's part of what I'm currently using.
Now that I understand what's going on - and the RX antenna array maps
to what the receive LNA configuration actually is - I feel comfortable
in enabling this.
If people do have issues with this, there's enough debugging now available
that we have a chance to diagnose it without writing it up as 'weird
crap.'
Tested:
* AR9285 STA w/ diversity combining enabled in EEPROM
TODO:
* (More) testing in hostap mode
and controlling this form of antenna diversity) - print out the AR9285
antenna diversity configuration at attach time.
This will help track down and diagose if/when people have connectivity
issues on cards (eg if they connect a single antenna to LNA1, yet the
card has RX configured to only occur on LNA2.)
Tested:
* AR9285 w/ antenna diversity enabled in EEPROM;
* AR9285 w/ antenna diversity disabled in EEPROM; mapping only to a
single antenna (LNA1.)
the RX antenna field.
The AR9285/AR9485 use an LNA mixer to determine how to combine the signals
from the two antennas. This is encoded in the RSSI fields (ctl/ext) for
chain 2. So, let's use that here.
This maps RX antennas 0->3 to the RX mixer configuration used to
receive a frame. There's more that can be done but this is good enough
to diagnose if the hardware is doing "odd" things like trying to
receive frames on LNA2 (ie, antenna 2 or "alt" antenna) when there's
only one antenna connected.
Tested:
* AR9285, STA mode
for the RX path.
This is different to the div comb HAL flag, that says it actually
can use this for RX diversity (the "slow" diversity path implemented
but disabled in the AR9285 HAL code.)
Tested:
* AR9285, STA operation
* Grab the reset lock first, so any subsequent interrupt, TX, RX work
will fail
* Then shut down interrupts
* Then wait for TX/RX to finish running
At this point no further work will be running, so it's safe to do the
reset path code.
PR: kern/179232
The main problem here is that fast and driver RX diversity isn't actually
configured; I need to figure out why that is. That said, this makes
the single-antenna connected AR9285 and AR2427 (AR9285 w/ no 11n) work
correctly.
PR: kern/179269
and if queue mechanism; also fix up (non-11n) TX fragment handling.
This may result in a bit of a performance drop for now but I plan on
debugging and resolving this at a later stage.
Whilst here, fix the transmit path so fragment transmission works.
The TX fragmentation handling is a bit more special. In order to
correctly transmit TX fragments, there's a bunch of corner cases that
need to be handled:
* They must be transmitted back to back, in the same order..
* .. ie, you need to hold the TX lock whilst transmitting this
set of fragments rather than interleaving it with other MSDUs
destined to other nodes;
* The length of the next fragment is required when transmitting, in
order to correctly set the NAV field in the current frame to the
length of the next frame; which requires ..
* .. that we know the transmit duration of the next frame, which ..
* .. requires us to set the rate of all fragments to the same length,
or make the decision up-front, etc.
To facilitate this, I've added a new ath_buf field to describe the
length of the next fragment. This avoids having to keep the mbuf
chain together. This used to work before my 11n TX path work because
the ath_tx_start() routine would be handed a single mbuf with m_nextpkt
pointing to the next frame, and that would be maintained all the way
up to when the duration calculation was done. This doesn't hold
true any longer - the actual queuing may occur at any point in the
future (think ath_node TID software queuing) so this information
needs to be maintained.
Right now this does work for non-11n frames but it doesn't at all
enforce the same rate control decision for all frames in the fragment.
I plan on fixing this in a followup commit.
RTS/CTS has the same issue, I'll look at fixing this in a subsequent
commit.
Finaly, 11n fragment support requires the driver to have fully
decided what the rate scenario setup is - including 20/40MHz,
short/long GI, STBC, LDPC, number of streams, etc. Right now that
decision is (currently) made _after_ the NAV field value is updated.
I'll fix all of this in subsequent commits.
Tested:
* AR5416, STA, transmitting 11abg fragments
* AR5416, STA, 11n fragments work but the NAV field is incorrect for
the reasons above.
TODO:
* It would be nice to be able to queue mbufs per-node and per-TID so
we can only queue ath_buf entries when it's time to assemble frames
to send to the hardware.
But honestly, we should just do that level of software queue management
in net80211 rather than ath(4), so I'm going to leave this alone for now.
* More thorough AP, mesh and adhoc testing.
* Ensure that net80211 doesn't hand us fragmented frames when A-MPDU has
been negotiated, as we can't do software retransmission of fragments.
* .. set CLRDMASK when transmitting fragments, just to ensure.
traffic.
When transmitting non-aggregate traffic, we need to keep the hardware
busy whilst transmitting or small bursts in txdone/tx latency will
kill us.
This restores non-aggregate iperf performance, especially when doing
TDMA.
Tested:
* AR5416<->AR5416, TDMA
* AR5416 STA <-> AR9280 AP
of course.)
There's a few things that needed to happen:
* In case someone decides to set the beacon transmission rate to be
at an MCS rate, use the MCS-aware version of the duration calculation
to figure out how long the received beacon frame was.
* If TxOP enforcing is available on the hardware and we're doing TDMA,
enable it after a reset and set the TDMA guard interval to zero.
This seems to behave fine.
TODO:
* Although I haven't yet seen packet loss, the PHY errors that would be
triggered (specifically Transmit-Override-Receive) aren't enabled
by the 11n HAL. I'll have to do some work to enable these PHY errors
for debugging.
What broke:
* My recent changes to the TX queue handling has resulted in the driver
not keeping the hardware queue properly filled when doing non-aggregate
traffic. I have a patch to commit soon which fixes this situation
(albeit by reminding me about how my ath driver locking isn't working
out, sigh.)
So if you want to test this without updating to the next set of patches
that I commit, just bump the sysctl dev.ath.X.hwq_limit from 2 to 32.
Tested:
* AR5416 <-> AR5416, with ampdu disabled, HT40, 5GHz, MCS12+Short-GI.
I saw 30mbit/sec in both directions using a bidirectional UDP test.
The list-based DMA engine has the following behaviour:
* When the DMA engine is in the init state, you can write the first
descriptor address to the QCU TxDP register and it will work.
* Then when it hits the end of the list (ie, it either hits a NULL
link pointer, OR it hits a descriptor with VEOL set) the QCU
stops, and the TxDP points to the last descriptor that was transmitted.
* Then when you want to transmit a new frame, you can then either:
+ write the head of the new list into TxDP, or
+ you write the head of the new list into the link pointer of the
last completed descriptor (ie, where TxDP points), then kick
TxE to restart transmission on that QCU>
* The hardware then will re-read the descriptor to pick up the link
pointer and then jump to that.
Now, the quirks:
* If you write a TxDP when there's been no previous TxDP (ie, it's 0),
it works.
* If you write a TxDP in any other instance, the TxDP write may actually
fail. Thus, when you start transmission, it will re-read the last
transmitted descriptor to get the link pointer, NOT just start a new
transmission.
So the correct thing to do here is:
* ALWAYS use the holding descriptor (ie, the last transmitted descriptor
that we've kept safe) and use the link pointer in _THAT_ to transmit
the next frame.
* NEVER write to the TxDP after you've done the initial write.
* .. also, don't do this whilst you're also resetting the NIC.
With this in mind, the following patch does basically the above.
* Since this encapsulates Sam's issues with the QCU behaviour w/ TDMA,
kill the TDMA special case and replace it with the above.
* Add a new TXQ flag - PUTRUNNING - which indicates that we've started
DMA.
* Clear that flag when DMA has been shutdown.
* Ensure that we're not restarting DMA with PUTRUNNING enabled.
* Fix the link pointer logic during TXQ drain - we should always ensure
the link pointer does point to something if there's a list of frames.
Having it be NULL as an indication that DMA has finished or during
a reset causes trouble.
Now, given all of this, i want to nuke axq_link from orbit. There's now HAL
methods to get and set the link pointer of a descriptor, so what we
should do instead is to update the right link pointer.
* If there's a holding descriptor and an empty TXQ list, set the
link pointer of said holding descriptor to the new frame.
* If there's a non-empty TXQ list, set the link pointer of the
last descriptor in the list to the new frame.
* Nuke axq_link from orbit.
Note:
* The AR9380 doesn't need this. FIFO TX writes are atomic. As long as
we don't append to a list of frames that we've already passed to the
hardware, all of the above doesn't apply. The holding descriptor stuff
is still needed to ensure the hardware can re-read a completed
descriptor to move onto the next one, but we restart DMA by pushing in
a new FIFO entry into the TX QCU. That doesn't require any real
gymnastics.
Tested:
* AR5210, AR5211, AR5212, AR5416, AR9380 - STA mode.
doesn't match the actual hardware queue this frame is queued to.
I'm trying to ensure that the holding buffers are actually being queued
to the same TX queue as the holding buffer that they end up on.
I'm pretty sure this is all correct so if this complains, it'll be due
to some kind of subtle broken-ness that needs fixing.
This is only done for legacy hardware, not EDMA hardware.
Tested:
* AR5416 STA mode, very lightly
PS-POLL support.
This implements PS-POLL awareness i nthe
* Implement frame "leaking", which allows for a software queue
to be scheduled even though it's asleep
* Track whether a frame has been leaked or not
* Leak out a single non-AMPDU frame when transmitting aggregates
* Queue BAR frames if the node is asleep
* Direct-dispatch the rest of control and management frames.
This allows for things like re-association to occur (which involves
sending probe req/resp as well as assoc request/response) when
the node is asleep and then tries reassociating.
* Limit how many frames can set in the software node queue whilst
the node is asleep. net80211 is already buffering frames for us
so this is mostly just paranoia.
* Add a PS-POLL method which leaks out a frame if there's something
in the software queue, else it calls net80211's ps-poll routine.
Since the ath PS-POLL routine marks the node as having a single frame
to leak, either a software queued frame would leak, OR the next queued
frame would leak. The next queued frame could be something from the
net80211 power save queue, OR it could be a NULL frame from net80211.
TODO:
* Don't transmit further BAR frames (eg via a timeout) if the node is
currently asleep. Otherwise we may end up exhausting management frames
due to the lots of queued BAR frames.
I may just undo this bit later on and direct-dispatch BAR frames
even if the node is asleep.
* It would be nice to burst out a single A-MPDU frame if both ends
support this. I may end adding a FreeBSD IE soon to negotiate
this power save behaviour.
* I should make STAs timeout of power save mode if they've been in power
save for more than a handful of seconds. This way cards that get
"stuck" in power save mode don't stay there for the "inactivity" timeout
in net80211.
* Move the queue depth check into the driver layer (ath_start / ath_transmit)
rather than doing it in the TX path.
* There could be some naughty corner cases with ps-poll leaking.
Specifically, if net80211 generates a NULL data frame whilst another
transmitter sends a normal data frame out net80211 output / transmit,
we need to ensure that the NULL data frame goes out first.
This is one of those things that should occur inside the VAP/ic TX lock.
Grr, more investigations to do..
Tested:
* STA: AR5416, AR9280
* AP: AR5416, AR9280, AR9160
* Move the node sleep/wake state under the TX lock rather than the
node lock. Let's leave the node lock protecting rate control only
for now.
* When reassociating, various state needs to be cleared. For example,
the aggregate session needs to be torn down, including any pending
aggregation negotiation and BAR TX waiting.
* .. and we need to do a "cleanup" pass since frames in the hardware
TX queue need to be transmitted.
Modify ath_tx_tid_cleanup() to be called with the TX lock held and push
frames into a completion list. This allows for the cleanup to be
done atomically for all TIDs in a node rather than grabbing and
releasing the TX lock each time.
a non-loss reset.
When the drain functions are called, the holding descriptor and link pointers
are NULLed out.
But when the processq function is called during a non-loss reset, this
doesn't occur. So the next time a DMA occurs, it's chained to a descriptor
that no longer exists and the hardware gets angry.
Tested:
* AR5416, STA mode; use sysctl dev.ath.X.forcebstuck=1 to force a non-loss
reset.
TODO:
* Further AR9380 testing just to check that the behaviour for the EDMA
chips is sane.
PR: kern/178477
of "right".)
Flip back on the "always continue TX DMA using the holding descriptor"
code - by always setting ATH_BUF_BUSY and never setting axq_link to NULL.
Since the holding descriptor is accessed via txq->axq_link and _that_
is done behind the TXQ lock rather than the TX path lock, the holding
descriptor stuff itself needs to be behind the TXQ lock.
So, do the mental gymnastics needed to do this.
I've not seen any of the hardware failures that I was seeing when
I last tried to do this.
Tested:
* AR5416, STA mode
