RE: [PATCH rtw-next v7 2/3] wifi: rtw88: support channel switch in AP mode

[Ping-Ke Shih <pkshih@realtek.com>]

Mehmet Fide <mehmet.fide@gmail.com> wrote:
> From: Mehmet Fide <mehmet.fide@screeningeagle.com>
> 
> hostapd's CHAN_SWITCH is refused because the driver does not announce
> channel switch support, so an rtw88 AP can only change its channel by
> being torn down and started again.
> 
> Declare WIPHY_FLAG_HAS_CHANNEL_SWITCH and implement
> channel_switch_beacon: the firmware repeats the beacon held in the
> first reserved page, so while a switch is announced the page is
> downloaded again every beacon interval to advance the countdown, and
> ieee80211_csa_finish() is called once it completes. IBSS shares the
> page and the work.
> 
> The work is a delayed work of the device and csa_vif names the
> interface, both under the driver mutex. The countdown is cancelled when
> the AP stops, when the interface goes away, on WoWLAN suspend and in
> rtw_core_stop(); the BSS_CHANGED_BEACON replay after a hardware restart
> resumes it. The other page downloads during a countdown, the TIM update,
> the PG backup and the one on association, are skipped until the beacon
> after the switch, since every beacon fetch advances the countdown; the
> next download carries their changes. A scan is refused: it would take
> the AP off the channel its stations count down to.
> 
> Signed-off-by: Mehmet Fide <mehmet.fide@screeningeagle.com>

Acked-by: Ping-Ke Shih <pkshih@realtek.com>