cfg80211: implement APIs for dedicated radar detection HW

If a dedicated (off-channel) radar detection hardware (chain)
is available in the hardware/driver, allow this to be used by
calling the NL80211_CMD_RADAR_DETECT command with a new flag
attribute requesting off-channel radar detection is used.

Offchannel CAC (channel availability check) avoids the CAC
downtime when switching to a radar channel or when turning on
the AP.

Drivers advertise support for this using the new feature flag
NL80211_EXT_FEATURE_RADAR_OFFCHAN.

Tested-by: Evelyn Tsai <evelyn.tsai@mediatek.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/7468e291ef5d05d692c1738d25b8f778d8ea5c3f.1634979655.git.lorenzo@kernel.org
Link: https://lore.kernel.org/r/1e60e60fef00e14401adae81c3d49f3e5f307537.1634979655.git.lorenzo@kernel.org
Link: https://lore.kernel.org/r/85fa50f57fc3adb2934c8d9ca0be30394de6b7e8.1634979655.git.lorenzo@kernel.org
Link: https://lore.kernel.org/r/4b6c08671ad59aae0ac46fc94c02f31b1610eb72.1634979655.git.lorenzo@kernel.org
Link: https://lore.kernel.org/r/241849ccaf2c228873c6f8495bf87b19159ba458.1634979655.git.lorenzo@kernel.org
[remove offchan_mutex, fix cfg80211_stop_offchan_radar_detection(),
 remove gfp_t argument, fix documentation, fix tracing]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

2 files changed, 38 insertions, 0 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 423f97b982ff..db8866d42a4b 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -4072,6 +4072,15 @@ struct mgmt_frame_regs {
  * @set_fils_aad: Set FILS AAD data to the AP driver so that the driver can use
  *	those to decrypt (Re)Association Request and encrypt (Re)Association
  *	Response frame.
+ *
+ * @set_radar_offchan: Configure dedicated offchannel chain available for
+ *	radar/CAC detection on some hw. This chain can't be used to transmit
+ *	or receive frames and it is bounded to a running wdev.
+ *	Offchannel radar/CAC detection allows to avoid the CAC downtime
+ *	switching to a different channel during CAC detection on the selected
+ *	radar channel.
+ *	The caller is expected to set chandef pointer to NULL in order to
+ *	disable offchannel CAC/radar detection.
  */
 struct cfg80211_ops {
 	int	(*suspend)(struct wiphy *wiphy, struct cfg80211_wowlan *wow);
@@ -4404,6 +4413,8 @@ struct cfg80211_ops {
 				struct cfg80211_color_change_settings *params);
 	int     (*set_fils_aad)(struct wiphy *wiphy, struct net_device *dev,
 				struct cfg80211_fils_aad *fils_aad);
+	int	(*set_radar_offchan)(struct wiphy *wiphy,
+				     struct cfg80211_chan_def *chandef);
 };
 
 /*
@@ -7633,6 +7644,20 @@ void cfg80211_cac_event(struct net_device *netdev,
 			const struct cfg80211_chan_def *chandef,
 			enum nl80211_radar_event event, gfp_t gfp);
 
+/**
+ * cfg80211_offchan_cac_event - Channel Availability Check (CAC) offchan event
+ * @wiphy: the wiphy
+ * @chandef: chandef for the current channel
+ * @event: type of event
+ *
+ * This function is called when a Channel Availability Check (CAC) is finished,
+ * started or aborted by a offchannel dedicated chain.
+ *
+ * Note that this acquires the wiphy lock.
+ */
+void cfg80211_offchan_cac_event(struct wiphy *wiphy,
+				const struct cfg80211_chan_def *chandef,
+				enum nl80211_radar_event event);
 
 /**
  * cfg80211_gtk_rekey_notify - notify userspace about driver rekeying
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 61cab81e920d..3e734826792f 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -2639,6 +2639,13 @@ enum nl80211_commands {
  *	Mandatory parameter for the transmitting interface to enable MBSSID.
  *	Optional for the non-transmitting interfaces.
  *
+ * @NL80211_ATTR_RADAR_OFFCHAN: Configure dedicated offchannel chain available for
+ *	radar/CAC detection on some hw. This chain can't be used to transmit
+ *	or receive frames and it is bounded to a running wdev.
+ *	Offchannel radar/CAC detection allows to avoid the CAC downtime
+ *	switching on a different channel during CAC detection on the selected
+ *	radar channel.
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -3145,6 +3152,8 @@ enum nl80211_attrs {
 	NL80211_ATTR_MBSSID_CONFIG,
 	NL80211_ATTR_MBSSID_ELEMS,
 
+	NL80211_ATTR_RADAR_OFFCHAN,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
@@ -6051,6 +6060,9 @@ enum nl80211_feature_flags {
  *	frames. Userspace has to share FILS AAD details to the driver by using
  *	@NL80211_CMD_SET_FILS_AAD.
  *
+ * @NL80211_EXT_FEATURE_RADAR_OFFCHAN: Device supports offchannel radar/CAC
+ *	detection.
+ *
  * @NUM_NL80211_EXT_FEATURES: number of extended features.
  * @MAX_NL80211_EXT_FEATURES: highest extended feature index.
  */
@@ -6117,6 +6129,7 @@ enum nl80211_ext_feature_index {
 	NL80211_EXT_FEATURE_PROT_RANGE_NEGO_AND_MEASURE,
 	NL80211_EXT_FEATURE_BSS_COLOR,
 	NL80211_EXT_FEATURE_FILS_CRYPTO_OFFLOAD,
+	NL80211_EXT_FEATURE_RADAR_OFFCHAN,
 
 	/* add new features before the definition below */
 	NUM_NL80211_EXT_FEATURES,