This reworks the ath9k driver to schedule transmissions to connected
stations in a way that enforces airtime fairness between them. It
accomplishes this by measuring the time spent transmitting to or
receiving from a station at TX and RX completion, and accounting this to
a per-station, per-QoS level airtime deficit. Then, an FQ-CoDel based
deficit scheduler is employed at packet dequeue time, to control which
station gets the next transmission opportunity.

Airtime fairness can significantly improve the efficiency of the network
when station rates vary. The following throughput values are from a
simple three-station test scenario, where two stations operate at the
highest HT20 rate, and one station at the lowest, and the scheduler is
employed at the access point:

                  Before   /   After
Fast station 1:    19.17   /   25.09 Mbps
Fast station 2:    19.83   /   25.21 Mbps
Slow station:       2.58   /    1.77 Mbps
Total:             41.58   /   52.07 Mbps

The benefit of airtime fairness goes up the more stations are present.
In a 30-station test with one station artificially limited to 1 Mbps,
we have seen aggregate throughput go from 2.14 to 17.76 Mbps.
Signed-off-by: NToke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>

This switches ath9k over to using the mac80211 intermediate software
queueing mechanism for data packets. It removes the queueing inside the
driver, except for the retry queue, and instead pulls from mac80211 when
a packet is needed. The retry queue is used to store a packet that was
pulled but can't be sent immediately.

The old code path in ath_tx_start that would queue packets has been
removed completely, as has the qlen limit tunables (since there's no
longer a queue in the driver to limit).

The mac80211 intermediate software queues offer significant latency
reductions, and this patch allows ath9k to realise them. The exact gains
from this varies with the test scenario, but in an access point scenario
we have seen latency reductions ranging from 1/3 to as much as an order
of magnitude. We also achieve slightly better aggregation.

Median latency (ping) figures with this patch applied at the access point,
with two high-rate stations and one low-rate station (HT20 5Ghz), running
a Flent rtt_fair_var_up test with one TCP flow and one ping flow going to
each station:

                                 Fast station        Slow station
Default pfifo_fast qdisc:            430.4 ms            638.7 ms
fq_codel qdisc on iface:              35.5 ms            211.8 ms
This patch set:                       22.4 ms             38.2 ms

Median aggregation sizes over the same test:

Default pfifo_fast qdisc:            9.5 pkts            1.9 pkts
fq_codel qdisc on iface:            11.2 pkts            1.9 pkts
This patch set:                     13.9 pkts            1.9 pkts

This patch is based on Tim's original patch set, but reworked quite
thoroughly.

Cc: Tim Shepard <shep@alum.mit.edu>
Cc: Felix Fietkau <nbd@nbd.name>
Signed-off-by: NToke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>

Add the following to support beacon report radio measurement
with the measurement mode field set to passive or active:
1. Propagate the required scan duration to the device
2. Report the scan start time (in terms of TSF)
3. Report each BSS's detection time (also in terms of TSF)

TSF times refer to the BSS that the interface that requested the
scan is connected to.
Signed-off-by: NAssaf Krauss <assaf.krauss@intel.com>
Signed-off-by: NAvraham Stern <avraham.stern@intel.com>
[changed ath9k/10k, at76c59x-usb, iwlegacy, wl1251 and wlcore to match
the new API]
Signed-off-by: NLuca Coelho <luciano.coelho@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

This enum is already perfectly aliased to enum nl80211_band, and
the only reason for it is that we get IEEE80211_NUM_BANDS out of
it. There's no really good reason to not declare the number of
bands in nl80211 though, so do that and remove the cfg80211 one.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

drivers/net/wireless/ath/ath9k/channel.c:230: warning: type qualifiers ignored on function return type
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>

Request NOA update when chanctx active, also in case
of STA.
Signed-off-by: NJanusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>

This is useful for MCC debugging and bug fixing.
Signed-off-by: NJanusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>

In case we get BSS_CHANGED_P2P_PS early, from
mac80211, we didn't set NOA timer correctly,
while p2p_ps_vif was NULL.
Signed-off-by: NJanusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>

When adding NOA attr enable Opportunistic Power Save.
Before we calculate ctwindow but didn't enable oppps.
Signed-off-by: NJanusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>

After queue nullfunc for MCC case, we hit WARN_ON
in xmit.c:2398 while skb priority wasn't set.
Signed-off-by: NJanusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>

Use u32 while ath9k_hw_gettsf32() and
ath9k_hw_gen_timer_start() require u32.
Signed-off-by: NJanusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>

AP/GO will aprear after NOA, wait 1ms to be sure AP
could receive/answer this frames.
Signed-off-by: NJanusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>

In case of low HZ before this patch we saw wrong
values in debug message. Print real timeout value.
Signed-off-by: NJanusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>

Add/extend debug messages when chanctx used.
Signed-off-by: NJanusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>

In case we will get ROC cancel from mac80211 we
should not call ieee80211_remain_on_channel_expired().

In other case I hit such warning on MIPS and
p2p negotiation failed (tested with use_chanctx=1).

ath: phy0: Starting RoC period
ath: phy0: Channel definition created: 2412 MHz
ath: phy0: Assigned next_chan to 2412 MHz
ath: phy0: Offchannel duration for chan 2412 MHz : 506632
ath: phy0: ath_chanctx_set_next: current: 2412 MHz, next: 2412 MHz
ath: phy0: Stopping current chanctx: 2412
ath: phy0: Flush timeout: 200
ath: phy0: ath_chanctx_set_next: Set channel 2412 MHz
ath: phy0: Set channel: 2412 MHz width: 0
ath: phy0: Reset to 2412 MHz, HT40: 0 fastcc: 0
ath: phy0: cur_chan: 2412 MHz, event: ATH_CHANCTX_EVENT_TSF_TIMER, state: ATH_CHANCTX_STATE_IDLE
ath: phy0: ath_offchannel_channel_change: offchannel state: ATH_OFFCHANNEL_ROC_START
ath: phy0: cur_chan: 2412 MHz, event: ATH_CHANCTX_EVENT_SWITCH, state: ATH_CHANCTX_STATE_IDLE
ath: phy0: Cancel RoC
ath: phy0: RoC aborted
ath: phy0: RoC request on vif: 00:03:7f:4e:a0:cd, type: 1 duration: 500
ath: phy0: Starting RoC period
ath: phy0: Channel definition created: 2412 MHz
ath: phy0: Assigned next_chan to 2412 MHz
ath: phy0: Offchannel duration for chan 2412 MHz : 506705
ath: phy0: ath_chanctx_set_next: current: 2412 MHz, next: 2412 MHz
ath: phy0: ath_offchannel_channel_change: offchannel state: ATH_OFFCHANNEL_ROC_START
ath: phy0: cur_chan: 2412 MHz, event: ATH_CHANCTX_EVENT_SWITCH, state: ATH_CHANCTX_STATE_IDLE
------------[ cut here ]------------
WARNING: CPU: 0 PID: 3312 at drivers/net/wireless/ath/ath9k/main.c:2319
Modules linked in: ath9k ath9k_common ath9k_hw ath mac80211 cfg80211
Signed-off-by: NJanusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: NKalle Valo <kvalo@codeaurora.org>

Allow drivers to support NL80211_SCAN_FLAG_RANDOM_ADDR with software
based scanning and generate a random MAC address for them for every
scan request with the flag.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Currently, when a roc period expires, the offchannel
timer calls ieee80211_remain_on_channel_expired(), but
the roc state is cleared only when the queued work
to switch to the operating channel gets a chance to run.

This race is a problem because mac80211 can issue a
new roc request in this window. To avoid this, handle
roc completion in the offchannel timer itself.
Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

In a GO/STA setup, when we switch to the STA context,
the channel context timer is scheduled with a period of
half the beacon interval. If a beacon is received in
this duration, the timer is adjusted to accommodate
TSF sync done by the HW.

But, if the actual channel switch is delayed for some
reason, we end up rearming the timer every time a new
beacon is received. Avoid this by doing the adjustment
only once.
Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

When a pending roc or scan operation is cancelled,
the offchannel operation is cleared, but the offchannel
state in the main scheduler is not cleared. This causes
problems since an active GO will try to process a stale
offchannel request that was deferred earlier. Fix this
by clearing the state when there is no pending offchannel
(roc/scan) operation.
Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

and rename exports from ath9k_spectral_* to ath9k_cmn_spectral_*
Signed-off-by: NOleksij Rempel <linux@rempel-privat.de>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

last preparation before moving ath9k_spectral_scan_ to spectral.c
Signed-off-by: NOleksij Rempel <linux@rempel-privat.de>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

we don't have here any ieee80211_hw dependencies any way.
Signed-off-by: NOleksij Rempel <linux@rempel-privat.de>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Signed-off-by: NOleksij Rempel <linux@rempel-privat.de>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

The flush timeout in MCC mode is very small, since
we are constrained by the time slice for each
channel context, but since only the HW queues are
flushed when switching contexts, it is acceptable.

Since the SW queues are also emptied in the mac80211 flush()
callback, a larger duration is needed. Add an override
argument to __ath9k_flush() and set it when flush()
is called in MCC mode. This allows the driver to
drain both the SW and HW queues.
Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Instead of using ATH_CHANCTX_EVENT_ASSIGN to abort
a HW scan when a new interface becomes active, use the
mgd_prepare_tx() callback. This allows us to make
sure that the GO's channel becomes operational by
using flush_work().
Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

This patch makes sure that a GO interface
sends out a new NoA schedule with 200ms duration
when mgd_prepare_tx() is called.
Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

mac80211 has to be notified when a RoC period
expires in the driver. In MCC mode, since the
offchannel/RoC timer is set with the requested
duration, ieee80211_remain_on_channel_expired() needs
to be called when the timer expires.

But, currently it is done after we move back to
the operating channel. This is incorrect - fix this
by calling ieee80211_remain_on_channel_expired() when
the RoC timer expires and in ath_roc_complete() when
the RoC request is aborted.
Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

If a GO interface is active when we receive a
mgd_prepare_tx() call, then we need to send
out a new NoA before switching to a new context.
Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Pending frames in the driver can be present
either in the HW queues or SW. ath9k_has_pending_frames()
currently checks for the HW queues first and then
checks if any ACs are queued in the driver.

In MCC mode, we need to check the HW queues alone, since
the SW queues are just marked as 'stopped' - they will
be processed in the next context switch. But since we
don't differentiate this now, mention whether we want
to check if there are frames in the SW queues.

* The flush() callback checks both HW and SW queues.
* The tx_frames_pending() callback does the same.
* The call to __ath9k_flush() in MCC mode checks HW queues alone.
Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

An offchannel operation also needs to have
a flush timeout that doesn't exceed the NoA
absence duration of a GO context, so use
channel_switch_time. The first offchannel
operation is set a flush timeout of 10ms since
channel_switch_time will be zero.
Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

In MCC mode, the duration for a channel context
is half the beacon interval and having a large
flush timeout will adversely affect GO operation,
since the default value of 200ms will overshoot
the advertised NoA absence duration.

The scheduler initiates a channel context switch
only when the slot duration for the current
context expires, so there is no possibility of
having a fixed timeout for flush.

Since the channel_switch_time is added to the
absence duration when the GO sets up the NoA
attribute, this is the maximum time that we
have to flush the TX queues. The duration is very
small, but we don't have a choice in MCC mode.
Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

The timeout value for flushing the TX queues
is hardcoded at 200ms right now. Use a channel
context-specific value instead to allow adjustments
to the timeout in case MCC is enabled.
Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

When an active context transitions to inactive
state, the NoA schedule needs to be removed
for the context that has beaconing enabled.
Not doing this will affect p2p clients.
Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Instead of having ath_reset_internal() and ath_reset()
as two separate calls to perform a HW reset, have
one function. This makes sure that the behavior will
be the same at all callsites.
Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

When the current operating channel context has
been marked as ATH_CHANCTX_STATE_FORCE_ACTIVE,
do not process beacons that might be received,
since we have to wait for the station to become
authorized.

Also, since the cached TSF value will be zero
initially do not rearm the timer in this
case when a beacon is received, since it results
in spurious values.
Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

In MCC mode, currently the decision to enable
the multi-channel state machine is done
based on the association status if one of
the interfaces assigned to a context is in
station mode.

This allows the driver to switch to the other
context before the current station is able to
complete the 4-way handshake in case it is
required and this causes problems.

Instead, enable multi-channel mode when the
station moves to the authorized state. This
disallows an early switch to the other channel.
Signed-off-by: NSujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>