[PATCH rtw-next v5 0/3] wifi: rtw88: channel switch in AP mode

[Mehmet Fide <mehmet.fide@gmail.com>]

From: Mehmet Fide <mehmet.fide@screeningeagle.com>

An rtw88 AP cannot change its channel: the driver does not announce
channel switch support, so hostapd's CHAN_SWITCH is refused and the
only way is to tear the AP down. The series fixes the beacon download
the reserved page build makes twice, makes the TIM beacon update a
wiphy work, then implements channel_switch_beacon on top of the
firmware's beacon page.

v5:
- 2/3 is new: update_beacon_work becomes a wiphy work, so that it can
  look at the channel switch state under the wiphy lock; it checks
  RTW_FLAG_RUNNING instead of being cancelled in rtw_core_stop(), which
  runs without the wiphy lock on the IPS path (Ping-Ke)
- 3/3: rtw_fw_csa_active/start/stop() assert the wiphy lock (Ping-Ke)
- 3/3: hw_scan() takes the mutex with guard() (Ping-Ke)
- 3/3: a comment on the association download names the STA+AP
  combination it skips the download for (Ping-Ke)
- the whole set ran on a PROVE_LOCKING kernel without a lockdep report:
  switches with counts 1 to 100, hostapd stopped and restarted during
  a countdown, scans during a countdown, a firmware crash during a
  countdown, three stop/idle/start cycles, IBSS, 50 switches with a
  station attached, and on the RTL8822CU a station interface
  associating while the AP interface counted down

v4:
- 1/2: Reviewed-by from Luka
- 2/2: the countdown work is back in the device, initialised once,
  with csa_vif naming the interface; no interface iteration and no
  lookup through the reserved page any more (Ping-Ke)
- 2/2: the countdown is cancelled before a firmware recovery restarts
  the hardware, instead of guarding the work with flags (Ping-Ke)
- 2/2: the page download on association skips a running countdown,
  like the TIM update and the PG backup (Luka)
- 2/2: the scan refusal comes before the scan offload test, so that
  firmware without scan offload does not fall back to a software scan
  during a countdown (Luka)

v3:
- 1/2: the beacon out-pointer is initialised in the caller (Luka)
- 2/2: the countdown work lives in the interface, remove_interface
  cancels it unconditionally, the queue wrapper and the comments are
  gone (Ping-Ke)
- 2/2: the TIM update and the PG backup on set_key skip the page
  download while a switch is announced; every beacon fetch advances
  the countdown (Luka)
- 2/2: the commit message names the refused hardware scan (Ping-Ke)

v2:
- 2/2: a hardware scan is refused while a switch is announced
- the rtw89 mention is gone from the cover

Mehmet Fide (3):
  wifi: rtw88: download the beacon the reserved page was built with
  wifi: rtw88: update the beacon from a wiphy work
  wifi: rtw88: support channel switch in AP mode

 drivers/net/wireless/realtek/rtw88/fw.c       | 107 +++++++++++++++---
 drivers/net/wireless/realtek/rtw88/fw.h       |   6 +-
 drivers/net/wireless/realtek/rtw88/mac80211.c |  36 +++++-
 drivers/net/wireless/realtek/rtw88/main.c     |  13 ++-
 drivers/net/wireless/realtek/rtw88/main.h     |   4 +-
 5 files changed, 141 insertions(+), 25 deletions(-)

-- 
2.55.0