Depending on required latency requested by pm_qos (via mac80211)
we can automatically adjust the sleep state. Also, mac80211 has
a user-visible dynamic sleep feature where we are supposed to
stay awake after sending/receiving frames to better receive
response frames to our packets, this can be integrated into the
sleep command.

Currently, and this patch doesn't change that yet, we default
to using sleep level 1 if PS is enabled. With a module parameter
to iwlcore, automatic adjustment to changing network latency
requirements can be enabled -- this isn't yet the default due
to requiring more testing.

The goal is to enable automatic adjustment and then go into the
deepest possible sleep state possible depending on the networking
latency requirements.

This patch does, however, enable IEEE80211_HW_SUPPORTS_DYNAMIC_PS
to avoid the double-timer (one in software and one in the device)
when transmitting -- the exact timeout may be ignored but that is
not of big concern.

Note also that we keep the hard-coded power indices around for
thermal throttling -- the specification of that calls for using
the specified power levels. Those can also be selected in debugfs
to allow easier testing of such parameters.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Do not send CT KILL config command twice and correct critical
temperature informatiom in dmesg
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

When compiling without CONFIG_IWLWIFI_DEBUGFS there is a missing
iwl_update_stats symbol. This is fixed by making this function an inline in
the case when CONFIG_IWLWIFI_DEBUGFS is not set due to the hot path in
which it is used.
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Some of the thermal throttle data structures and code
are really very intermingled with the sleep (power)
control code. They really do belong together in a way
since the thermal throttle code uses powersaving to
achieve its goal, but it's making it hard to work on
the powersave code. Split this up to make that easier.
I've also changed the antenna defines to an enum and
used the same enum for RX and TX.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Modify the power update function, when driver fail to set the power, it
should not continue move forward and try to change the rx chain
configuration.
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

For legacy thermal throttling, set the new Thermal Throttling
state and change power index when thermal throttling manager detects
temperature changed. The current implementation sets the state to the
previous Thermal Throttling state, which causes system to enter wrong
power index. The worse case, it will trying to set the
lower power index when device reach critical temperature, it will cuase
issue for both system and the device.
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Move all the thermal throttling functions to background task to make
sure do not change power and rx chain in interrupt handler.
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

commit "iwlwifi: uCode Alive notification with timeout" introduced a more
reliable mechanism for ucode loading. Unfortunately we hit a problem with
it frequently enough to make a 4965 unusable. The problem can be seen in
debug log below. What this code attempts is to set runtime ucode up to
load, start a timer to wait for the alive response from runtime ucode, and
if it times out it tries again. As can be seen below we receive the alive
response and wake the waiting task _before_ the tasks starts waiting. The
task thus times out as the alive response is not received while it is
waiting for it and it restarts the device. This starts the cycle all over
again.

[29739.000819] ieee80211 phy0: U iwl_mac_start enter
[29739.005751] ieee80211 phy0: U iwl_prepare_card_hw iwl_prepare_card_hw enter
[29739.012798] ieee80211 phy0: U iwl_set_hw_ready hardware ready
[29739.057200] ieee80211 phy0: U iwl4965_load_bsm Begin load bsm
[29739.063366] ieee80211 phy0: U iwl4965_verify_bsm Begin verify bsm
[29739.072485] ieee80211 phy0: U iwl4965_verify_bsm BSM bootstrap uCode image OK
[29739.079671] ieee80211 phy0: U iwl4965_load_bsm BSM write complete, poll 0 iterations
[29739.257019] ieee80211 phy0: I iwl_rx_reply_alive Alive ucode status 0x00000001 revision 0x1 0x9
[29739.260964] ieee80211 phy0: I iwl_rx_reply_alive Initialization Alive received.
[29739.260964] ieee80211 phy0: U __iwl_up iwlagn is coming up
[29739.278571] ieee80211 phy0: U iwl_mac_start Start UP work done.
[29739.284509] ieee80211 phy0: U iwlcore_verify_inst_sparse ucode inst image size is 788
[29739.292432] ieee80211 phy0: U iwlcore_verify_inst_sparse ucode inst image size is 10312
[29739.302004] ieee80211 phy0: U iwl_verify_ucode Initialize uCode is good in inst SRAM
[29739.309746] ieee80211 phy0: U iwl4965_hw_get_temperature Running temperature calibration
[29739.317833] ieee80211 phy0: U iwl4965_hw_get_temperature Calib values R[1-3]: -36 13522 -13496 R4: -2726
[29739.327337] ieee80211 phy0: U iwl4965_hw_get_temperature Calibrated temperature: 310K, 37C
[29739.335598] ieee80211 phy0: U iwl4965_init_alive_start Initialization Alive received.
[29739.343477] ieee80211 phy0: U iwl4965_set_ucode_ptrs Runtime uCode pointers are set.
[29739.351283] ieee80211 phy0: I iwl_rx_reply_alive Alive ucode status 0x00000001 revision 0x1 0x0
[29739.355210] ieee80211 phy0: I iwl_rx_reply_alive Runtime Alive received.
[29739.366731] iwlagn 0000:03:00.0: Runtime uCode already alive? Waiting for alive anyway
[29743.284110] iwlagn 0000:03:00.0: START_ALIVE timeout after 4000ms.
[29743.290337] ieee80211 phy0: U iwl_mac_add_interface enter: type 2
[29744.364089] iwlagn 0000:03:00.0: Runtime timeout after 5000ms
[29744.370882] ieee80211 phy0: U iwl_alive_start Runtime Alive received.
[29744.377347] ieee80211 phy0: U iwlcore_verify_inst_sparse ucode inst image size is 788
[29744.385287] ieee80211 phy0: U iwlcore_verify_inst_sparse ucode inst image size is 10312
[29744.393397] ieee80211 phy0: U iwlcore_verify_inst_sparse ucode inst image size is 94720
[29744.415835] ieee80211 phy0: U iwl_verify_ucode Runtime uCode is good in inst SRAM
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Display sensitivity and chain noise data to help understand the current
environment and RF condition.

The data is feeded by statistics notification and Beacon from uCode;
then used by sensitivity calibration and chain noise calibration to
determine how DSP should react to the environment changes
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Display statistics notification information
The information break down into
    uCode_tx_stats
    uCode_rx_stats
    uCode_general_stats
and can be found in /sys/kernel/debug/ieee80211/phy0/iwlagn/debug
directory

The statistic information display in debugFs is based on the last
statistics notification from uCode; it might not reflect the current
uCode activity. Using "watch" command to monitor the uCode
activity should give up-to-date statistics provided by uCode.
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Adding debugfs function to show current TxFifo/RxFifo read/write
pointer, plus the current tx queue status (wake/stop) for both real and
virtual queue.
This is part of debug feature set to help debugging driver/uCode.

use tx_queue and rx_queue in
/sys/kernel/debug/ieee80211/phy0/iwlagn/debug directory to show the
current read/write pointer for both TxFifo and RxFifo queue
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Break down the traffic type and counter for both Tx and Rx.
Enhance the tx_statistics and rx_statistics debugfs function and move
to /sys/kernel/debug/ieee80211/phy0/iwlagn/debug directory to help
better debugging both driver and uCode related problems.
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

The traffic buffer will only beallocated and used if either bit 23
(IWL_DX_TX) or bit 24 (IWL_DL_RX) of "debug" is set;
example: "debug=0x800000" - log tx data traffic
         "debug=0x1000000" - log rx data traffic
         "debug=0x1800000" - log both tx and rx traffic

The traffic log will store the beginning portion (64 bytes)  of the
latest 256 of tx and rx packets in the round-robbin buffer for
debugging,
user can examine the log through debugfs file.

How to display the current logged tx/rx traffic and txfifo and rxfifo
read/write point:
"cat traffic_log" in /sys/kernel/debug/ieee80211/phy0/iwlagn/debug
directory

By echo "0" to traffic_log file will empty the traffic log buffer and
reset both tx and rx taffic log index to 0.
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Rename "fat" to "ht40"
The term "fat channel" is deprecated in favor of "HT40"
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Commit "iwlwifi: make debug level more user friendly" cleaned up the
debug level handling. In doing so it created a single global debug
level for all devices. Some setups do consits of more that one iwlwifi
device and in these setups there is a requirement that debug levels
should be unique per device.

We now re-introduce the per device debugging while maintaining the
cleanup effort of the previous patch.

The maintain the global debug level and now introduce a per-device debug
level that will be used if it (the per-device debug level) is set. The
per-device debug level can be controlled via the debug_level sysfs file
while the global debug level is controlled by the debug module parameter.
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Acked-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

version info in sysfs had been determined to be unnecessary as it
is already provided in syslog info.  nvm version is added to syslog
version info as a debug level message to provide all info that was
in the version sysfs data.
Signed-off-by: NJay Sternberg <jay.e.sternberg@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Remove the support for deprecated devices. These devices are
engineering samples and no longer supported by the uCode.
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

For 6x00 2x2 NIC, two types of Power Amplifier are available.
In order for uCode to apply correct tx power,
driver needs to program the CSR_GP_DRIVER_REG register and
let uCode know the type of PA.
If driver do not program CSR_GP_DRIVER_REG register (default to 0),
then it is uCode's decision for tx power

2x2 Hybrid card: use both internal and external PA
2x2 IPA(Internal Power Amplifier) card: internal PA only
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Resolve an issue in which out-dated fields in iwl_cmd_meta
could be used for later hardware commands.
Signed-off-by: NDaniel C Halperin <daniel.c.halperin@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

This is a private flag, internal to cfg80211. cfg80211
will set orig_* stuff internally upon wiphy registration,
drivers do not need to muck with it.
Signed-off-by: NLuis R. Rodriguez <lrodriguez@atheros.com>
Acked-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Even with the split into iwlcore/agn/3945 not all symbols
that cross file boundaries are needed in other modules, a
few are only used within iwlcore, for example.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Do all key clearing except sending sommands to device when rfkill
enabled. When rfkill enabled the interface is brought down and will
be brought back up correctly after rfkill is enabled again.

Same change is not needed for iwl3945 as it ignores return code when
sending key clearing command to device.

This fixes http://bugzilla.kernel.org/show_bug.cgi?id=13742Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Tested-by: NFrans Pop <elendil@planet.nl>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Move orthogonal error handling code up before a kzalloc, so that it
doesn't have to free the allocated data.

The semantic match that finds the problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@r exists@
local idexpression x;
statement S;
expression E;
identifier f,f1,l;
position p1,p2;
expression *ptr != NULL;
@@

x@p1 = \(kmalloc\|kzalloc\|kcalloc\)(...);
...
if (x == NULL) S
<... when != x
     when != if (...) { <+...x...+> }
(
x->f1 = E
|
 (x->f1 == NULL || ...)
|
 f(...,x->f1,...)
)
...>
(
 return \(0\|<+...x...+>\|ptr\);
|
 return@p2 ...;
)

@script:python@
p1 << r.p1;
p2 << r.p2;
@@

print "* file: %s kmalloc %s return %s" % (p1[0].file,p1[0].line,p2[0].line)
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Acked-by: NZhu Yi <yi.zhu@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

A regression was added through patch a4ed90d6:

"cfg80211: respect API on orig_flags on channel for beacon hint"

We did indeed respect _orig flags but the intention was not clearly
stated in the commit log. This patch fixes firmware issues picked
up by iwlwifi when we lift passive scan of beaconing restrictions
on channels its EEPROM has been configured to always enable.

By doing so though we also disallowed beacon hints on devices
registering their wiphy with custom world regulatory domains
enabled, this happens to be currently ath5k, ath9k and ar9170.
The passive scan and beacon restrictions on those devices would
never be lifted even if we did find a beacon and the hardware did
support such enhancements when world roaming.

Since Johannes indicates iwlwifi firmware cannot be changed to
allow beacon hinting we set up a flag now to specifically allow
drivers to disable beacon hints for devices which cannot use them.

We enable the flag on iwlwifi to disable beacon hints and by default
enable it for all other drivers. It should be noted beacon hints lift
passive scan flags and beacon restrictions when we receive a beacon from
an AP on any 5 GHz non-DFS channels, and channels 12-14 on the 2.4 GHz
band. We don't bother with channels 1-11 as those channels are allowed
world wide.

This should fix world roaming for ath5k, ath9k and ar9170, thereby
improving scan time when we receive the first beacon from any AP,
and also enabling beaconing operation (AP/IBSS/Mesh) on cards which
would otherwise not be allowed to do so. Drivers not using custom
regulatory stuff (wiphy_apply_custom_regulatory()) were not affected
by this as the orig_flags for the channels would have been cleared
upon wiphy registration.

I tested this with a world roaming ath5k card.

Cc: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: NLuis R. Rodriguez <lrodriguez@atheros.com>
Reviewed-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Add debugfs file to enable/disable HT40(40MHz) channel support.
By default, 40MHz is supported if AP can support the function.

By echo "1" to "disable_ht40" file, iwlwifi driver will disable the
40MHz support and only allow 20MHz channel.

Because the information exchange happen during association time,
so enable/disable ht40 channel only can be performed when it is not
associated with AP.
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

C [M]  drivers/net/wireless/iwlwifi/iwl-core.o
drivers/net/wireless/iwlwifi/iwl-core.c:1341: warning:
‘iwl_dump_nic_error_log’ defined but not used
Reported-by: NLuis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Commit "iwlwifi: Handle new firmware file with ucode build number
in header" introduced new ucode header parsing routines, but
neglected to initialize these routines for 1000. The system thus goes
into infinite loop trying to load ucode, failing every time with a null
pointer exception as it tries to parse the header.
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Acked-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

IWLWIFI_LEDS option should certainly have help comment, and should
default to y.
Signed-off-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Fix incorrect name for HT MPDU Density.
default set to 4 uSec
Reported-by: NSujith <Sujith.Manoharan@atheros.com>
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

This data is more useful to debugging that the receive
buffer contents.
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

No existing callbacks use anything other than the return
value 1, which means that the caller should free the
reply skb, so it seems safer in terms of not introducing
memory leaks to simply remove the return value and let
the caller always free the skb.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

The current command sending in iwlwifi is a bit of a mess:
 1) there is a struct, iwl_cmd, that contains both driver
    and device data in a single packed structure -- this
    is very confusing
 2) the on-stack data and the command metadata share a
    structure by embedding the latter in the former, which
    is also rather confusing because it leads to weird
    unions and similarly odd constructs
 3) each txq always has enough space for 256 commands,
    even if only 32 end up being used

This patch fixes these things:
 1) rename iwl_cmd to iwl_device_cmd and keep track of
    command metadata and device command separately, in
    two arrays in each tx queue
 2) remove the 'meta' member from iwl_host_cmd and only
    put in the required members
 3) allocate the cmd/meta arrays separately instead of
    embedding them into the txq structure
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Add debugfs function to display current thermal throttling status for
both Legacy and Advance Thermal Throttling Management
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Part 2 of Thermal Throttling Management -

Thermal Throttling feature is used to put NIC into low power state when
driver detect the Radio temperature reach pre-defined threshold

Two Thermal Throttling Management Methods; this patch introduce the
Advance Thermal Throttling:
TI-0: system power index, no tx/rx restriction, HT enabled
TI-1: power index 5, 1 spatial stream Tx, multiple spatial stream Rx, HT
enabled
TI-2: power index 5: 1 spatial stream Tx, 1 spatial stream Rx, HT
disabled
TI-CT-KILL: power index 5, no Tx, no Rx, HT disabled

For advance Thermal Throttling, CT_KILL_ENTER threshold and CT_KILL_EXIT
threshold are different; uCode will not stay awake until reach
CT_KILL_EXIT threshold.
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Part 1 of Thermal Throttling Management -

Thermal Throttling feature is used to put NIC into low power state when
driver detect the Radio temperature reach pre-defined threshold

Two Thermal Throttling Management Methods; this patch introduce the
Legacy Thermal Management:
   IWL_TI_0: normal temperature, system power state
   IWL_TI_1: high temperature detect, low power state
   IWL_TI_2: higher temperature detected, lower power state
   IWL_TI_CT_KILL: critical temperature detected, lowest power state

Once get into CT_KILL state, uCode go into sleep, driver will stop all
the active queues, then move to IWL_TI_CT_KILL state; also set up 5
seconds timer to toggle CSR flag, uCode wake up upon CSR flag change,
then measure the temperature.
If temperature is above CT_KILL exit threshold, uCode go backto sleep;
if temperature is below CT_KILL exit threshold, uCode send Card State
Notification response with appropriate CT_KILL status flag, and uCode
remain awake, Driver receive Card State Notification Response and update
the card temperature to the CT_KILL exit threshold.
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

If advance thermal throttling is used the driver need to pass both
"enter" and "exit" temperature to uCode.

Using different critical temperature threshold for legacy and advance
thermal throttling management based on the type of thermal throttling
method is used except 1000.
For 1000, it use advance thermal throttling critical temperature
threshold, but with legacy thermal management implementation until ucode
has the necessary implementations in place.
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

When performing rate scaling, if detected that the new rate
index is invalid, clear the search_better_tbl flag
so it will not be stuck in the loop.

Since the search table is already set up in uCode,
we need to empty out the the search table;
revert back to the "active" rate and throughput info.
Also pass the "active" table setup to uCode to make
sure the rate scale is functioning correctly.
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

tid is bounded (above) by the size of default_tid_to_tx_fifo (17 elements), but
the size of priv->stations[].tid[] is MAX_TID_COUNT (9) elements.
Signed-off-by: NRoel Kluin <roel.kluin@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

We need to provide a reasonable minimum that will result in a
working setup if used. Set minimum to be 10 to provide for
4 standard TX queues + 1 command queue + 2 (unused) HCCA queues +
4 HT queues (one per AC).

We allow the user to change the number of queues used via a module
parameter and use this minimum value to check if it is valid. Without
this patch a user can select a value for the number of queues that
will result in a failing setup.
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Reviewed-by: NTomas Winkler <tomas.winkler@intel.com>
Acked-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

I had a problem on 4965 hardware (well, probably other hardware too,
but others don't survive my stress testing right now, unfortunately)
where the driver was sending invalid commands to the device, but no
such thing could be seen from the driver's point of view. I could
reproduce this fairly easily by sending multiple TCP streams with
iperf on different TIDs, though sometimes a single iperf stream was
sufficient. It even happened with a single core, but I have forced
preemption turned on.

The culprit was a queue overrun, where we advanced the queue's write
pointer over the read pointer. After careful analysis I've come to
the conclusion that the cause is a race condition between iwlwifi
and mac80211.

mac80211, of course, checks whether the queue is stopped, before
transmitting a frame. This effectively looks like this:

        lock(queues)
        if (stopped(queue)) {
                unlock(queues)
                return busy;
	}
        unlock(queues)
        ...             <-- this place will be important
			    there is some more code here
        drv_tx(frame)

The driver, on the other hand, can stop and start queues, which does

        lock(queues)
        mark_running/stopped(queue)
        unlock(queues)

	[if marked running: wake up tasklet to send pending frames]

Now, however, once the driver starts the queue, mac80211 can see that
and end up at the marked place above, at which point for some reason the
driver seems to stop the queue again (I don't understand that) and then
we end up transmitting while the queue is actually full.

Now, this shouldn't actually matter much, but for some reason I've seen
it happen multiple times in a row and the queue actually overflows, at
which point the queue bites itself in the tail and things go completely
wrong.

This patch fixes this by just dropping the packet should this have
happened, and making the lock in iwlwifi cover everything so iwlwifi
can't race against itself (dropping the lock there might make it more
likely, but it did seem to happen without that too).

Since we can't hold the lock across drv_tx() above, I see no way to fix
this in mac80211, but I also don't understand why I haven't seen this
before -- maybe I just never stress tested it this badly.

With this patch, the device has survived many minutes of simultanously
sending two iperf streams on different TIDs with combined throughput
of about 60 Mbps.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>