Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
The pre-11n calculations include SIFS, but the 11n ones don't.
The reason is that (mostly) the 11n hardware is doing the SIFS calculation
for us but the pre-11n hardware isn't. This means that we're over-shooting
the times in the duration field for non-11n frames on 11n hardware, which
is OK, if not a little inefficient.
Now, this is all fine for what the hardware needs for doing duration math
for ACK, RTS/CTS, frame length, etc, but it isn't useful for doing PHY
duration calculations. Ie, given a frame to TX and its timestamp, what
would the end of the actual transmission time be; and similar for an
RX timestamp and figuring out its original length.
So, this adds a new field to the duration routines which requests
SIFS or no SIFS to be included. All the callers currently will call
it requesting SIFS, so this /should/ be a glorious no-op. I'm however
planning some future work around airtime fairness and positioning which
requires these routines to have SIFS be optional.
Notably though, the 11n version doesn't do any SIFS addition at the moment.
I'll go and tweak and verify all of the packet durations before I go and
flip that part on.
Tested:
* AR9330, STA mode
* AR9330, AP mode
* AR9380, STA mode
connectivity interact with the net80211 stack.
Historical background: originally wireless devices created an interface,
just like Ethernet devices do. Name of an interface matched the name of
the driver that created. Later, wlan(4) layer was introduced, and the
wlanX interfaces become the actual interface, leaving original ones as
"a parent interface" of wlanX. Kernelwise, the KPI between net80211 layer
and a driver became a mix of methods that pass a pointer to struct ifnet
as identifier and methods that pass pointer to struct ieee80211com. From
user point of view, the parent interface just hangs on in the ifconfig
list, and user can't do anything useful with it.
Now, the struct ifnet goes away. The struct ieee80211com is the only
KPI between a device driver and net80211. Details:
- The struct ieee80211com is embedded into drivers softc.
- Packets are sent via new ic_transmit method, which is very much like
the previous if_transmit.
- Bringing parent up/down is done via new ic_parent method, which notifies
driver about any changes: number of wlan(4) interfaces, number of them
in promisc or allmulti state.
- Device specific ioctls (if any) are received on new ic_ioctl method.
- Packets/errors accounting are done by the stack. In certain cases, when
driver experiences errors and can not attribute them to any specific
interface, driver updates ic_oerrors or ic_ierrors counters.
Details on interface configuration with new world order:
- A sequence of commands needed to bring up wireless DOESN"T change.
- /etc/rc.conf parameters DON'T change.
- List of devices that can be used to create wlan(4) interfaces is
now provided by net.wlan.devices sysctl.
Most drivers in this change were converted by me, except of wpi(4),
that was done by Andriy Voskoboinyk. Big thanks to Kevin Lo for testing
changes to at least 8 drivers. Thanks to pluknet@, Oliver Hartmann,
Olivier Cochard, gjb@, mmoll@, op@ and lev@, who also participated in
testing.
Reviewed by: adrian
Sponsored by: Netflix
Sponsored by: Nginx, Inc.
* 286410
* 286413
* 286416
The initial commit broke a variety of debug and features that aren't
in the GENERIC kernels but are enabled in other platforms.
with the net80211 stack.
Historical background: originally wireless devices created an interface,
just like Ethernet devices do. Name of an interface matched the name of
the driver that created. Later, wlan(4) layer was introduced, and the
wlanX interfaces become the actual interface, leaving original ones as
"a parent interface" of wlanX. Kernelwise, the KPI between net80211 layer
and a driver became a mix of methods that pass a pointer to struct ifnet
as identifier and methods that pass pointer to struct ieee80211com. From
user point of view, the parent interface just hangs on in the ifconfig
list, and user can't do anything useful with it.
Now, the struct ifnet goes away. The struct ieee80211com is the only
KPI between a device driver and net80211. Details:
- The struct ieee80211com is embedded into drivers softc.
- Packets are sent via new ic_transmit method, which is very much like
the previous if_transmit.
- Bringing parent up/down is done via new ic_parent method, which notifies
driver about any changes: number of wlan(4) interfaces, number of them
in promisc or allmulti state.
- Device specific ioctls (if any) are received on new ic_ioctl method.
- Packets/errors accounting are done by the stack. In certain cases, when
driver experiences errors and can not attribute them to any specific
interface, driver updates ic_oerrors or ic_ierrors counters.
Details on interface configuration with new world order:
- A sequence of commands needed to bring up wireless DOESN"T change.
- /etc/rc.conf parameters DON'T change.
- List of devices that can be used to create wlan(4) interfaces is
now provided by net.wlan.devices sysctl.
Most drivers in this change were converted by me, except of wpi(4),
that was done by Andriy Voskoboinyk. Big thanks to Kevin Lo for testing
changes to at least 8 drivers. Thanks to Olivier Cochard, gjb@, mmoll@,
op@ and lev@, who also participated in testing. Details here:
https://wiki.freebsd.org/projects/ifnet/net80211
Still, drivers: ndis, wtap, mwl, ipw, bwn, wi, upgt, uath were not
tested. Changes to mwl, ipw, bwn, wi, upgt are trivial and chances
of problems are low. The wtap wasn't compilable even before this change.
But the ndis driver is complex, and it is likely to be broken with this
commit. Help with testing and debugging it is appreciated.
Differential Revision: D2655, D2740
Sponsored by: Nginx, Inc.
Sponsored by: Netflix
to this event, adding if_var.h to files that do need it. Also, include
all includes that now are included due to implicit pollution via if_var.h
Sponsored by: Netflix
Sponsored by: Nginx, Inc.
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.
related issues.
Moving the TX locking under one lock made things easier to progress on
but it had one important side-effect - it increased the latency when
handling CABQ setup when sending beacons.
This commit introduces a bunch of new changes and a few unrelated changs
that are just easier to lump in here.
The aim is to have the CABQ locking separate from other locking.
The CABQ transmit path in the beacon process thus doesn't have to grab
the general TX lock, reducing lock contention/latency and making it
more likely that we'll make the beacon TX timing.
The second half of this commit is the CABQ related setup changes needed
for sane looking EDMA CABQ support. Right now the EDMA TX code naively
assumes that only one frame (MPDU or A-MPDU) is being pushed into each
FIFO slot. For the CABQ this isn't true - a whole list of frames is
being pushed in - and thus CABQ handling breaks very quickly.
The aim here is to setup the CABQ list and then push _that list_ to
the hardware for transmission. I can then extend the EDMA TX code
to stamp that list as being "one" FIFO entry (likely by tagging the
last buffer in that list as "FIFO END") so the EDMA TX completion code
correctly tracks things.
Major:
* Migrate the per-TXQ add/removal locking back to per-TXQ, rather than
a single lock.
* Leave the software queue side of things under the ATH_TX_LOCK lock,
(continuing) to serialise things as they are.
* Add a new function which is called whenever there's a beacon miss,
to print out some debugging. This is primarily designed to help
me figure out if the beacon miss events are due to a noisy environment,
issues with the PHY/MAC, or other.
* Move the CABQ setup/enable to occur _after_ all the VAPs have been
looked at. This means that for multiple VAPS in bursted mode, the
CABQ gets primed once all VAPs are checked, rather than being primed
on the first VAP and then having frames appended after this.
Minor:
* Add a (disabled) twiddle to let me enable/disable cabq traffic.
It's primarily there to let me easily debug what's going on with beacon
and CABQ setup/traffic; there's some DMA engine hangs which I'm finally
trying to trace down.
* Clear bf_next when flushing frames; it should quieten some warnings
that show up when a node goes away.
Tested:
* AR9280, STA/hostap, up to 4 vaps (staggered)
* AR5416, STA/hostap, up to 4 vaps (staggered)
TODO:
* (Lots) more AR9380 and later testing, as I may have missed something here.
* Leverage this to fix CABQ hanling for AR9380 and later chips.
* Force bursted beaconing on the chips that default to staggered beacons and
ensure the CABQ stuff is all sane (eg, the MORE bits that aren't being
correctly set when chaining descriptors.)
now this works for non-debug and debug builds.
* Add a comment reminding me (or someone) to audit all of the relevant
math to ensure there's no weird wrapping issues still lurking about.
But yes, this does seem to be mostly working.
Pointy-hat-to: adrian, yet again
* add some further debugging prints, which are quite nice to have
* add in ALQ hooks (optional!) to allow for the TDMA information to be
logged in-line with the TX and RX descriptor information.
The existing logic wrapped programming nexttbtt at 65535 TU.
This is not good enough for the 11n chips, whose nexttbtt register
(GENERIC_TIMER_0) has an initial value from 0..2^31-1 TSF.
So converting the TU to TSF had the counter wrap at (65535 << 10) TSF.
Once this wrap occured, the nexttbtt value was very very low, much
lower than the current TSF value. At this point, the nexttbtt timer
would constantly fire, leading to the TX queue being constantly gated
open.. and when this occured, the sender was not correctly transmitting
in its slot but just able to continuously transmit. The master would
then delay transmitting its beacon until after the air became free
(which I guess would be after the burst interval, before the next burst
interval would quickly follow) and that big delta in master beacon TX
would start causing big swings in the slot timing adjustment.
With this change, the nexttbtt value is allowed to go all the way up
to the maximum value permissable by the 32 bit representation.
I haven't yet tested it to that point; I really should. The AR5212
HAL now filters out values above 65535 TU for the beacon configuration
(and the relevant legal values for SWBA, DBA and NEXTATIM) and the
AR5416 HAL just dutifully programs in what it should.
With this, TDMA is now useful on the 802.11n chips.
Tested:
* AR5416, AR9280 TDMA slave
* AR5413 TDMA slave
TSF write.
The TSF_L32 update is fine for the AR5413 (and later, I guess) 11abg NICs
however on the 11n NICs this didn't work. The TSF writes were causing
a much larger time to be skipped, leading to the timing to never
converge.
I've tested this 64 bit TSF read, adjust and write on both the
11n NICs and the AR5413 NIC I've been using for testing. It works
fine on each.
This patch allows the AR5416/AR9280 to be used as a TDMA member.
I don't yet know why the AR9280 is ~7uS accurate rather than ~3uS;
I'll look into it soon.
Tested:
* AR5413, TDMA slave (~ 3us accuracy)
* AR5416, TDMA slave (~ 3us accuracy)
* AR9280, TDMA slave (~ 7us accuracy)
on the 802.11n NICs.
The 802.11n NICs return a TBTT value that continues far past the 16 bit
HAL_BEACON_PERIOD time (in TU.) The code would constrain nextslot to
HAL_BEACON_PERIOD, but it wasn't constraining nexttbtt - the pre-11n
NICs would only return TU values from 0 -> HAL_BEACON_PERIOD. Thus,
when nexttbtt exceeded 64 milliseconds, it would not wrap (but nextslot
did) which lead to a huge tsfdelta.
So until the slot calculation is converted to work in TSF rather than
a mix of TSF and TU, "make" the nexttbtt values match the TU assumptions
for pre-11n NICs.
This fixes the crazy deltatsf calculations but it doesn't fix the
non-convergent tsfdelta issue. That'll be fixed in a subsequent commit.
There's some TX path TDMA code in if_ath_tx.c which should be migrated
out, but first I should likely try and verify/fix/repair the TDMA support
in 9.x and -HEAD.
