[PATCH wireless-next] wifi: nl80211: add support to configure 6 GHz non-HT duplicate transmission

As per IEEE Std 802.11-2024, subclause 26.17.2.2, a 6 GHz AP can transmit
a Beacon frame using a non-HT duplicate PPDU, so that stations scanning
only PSC channels can discover it. Currently, there is no mechanism
to request the driver to transmit non-HT duplicate Beacon frames.

In [1], changes were made to parse the Beacon from user-space to set
the non-HT duplicate flag in the kernel. However, it was suggested that
non-HT transmission be part of the Beacon TX rate settings. Hence, add
NL80211_TXRATE_6GHZ_NON_HT_DUP as a flag attribute under
NL80211_ATTR_TX_RATES to let user-space request the driver to transmit
non-HT duplicate Beacons.

Also add validation to reject the Beacon if non-HT duplicate Beacon
transmission is enabled when legacy rates are not configured.

[1]  https://lore.kernel.org/all/[email protected]/

Signed-off-by: Manish Dharanenthiran <[email protected]>
---
Note: Users(ath11k&ath12k) of this new NL attribute will be posted later
once this gets approved.
---
 include/net/cfg80211.h       |  1 +
 include/uapi/linux/nl80211.h |  4 ++++
 net/wireless/nl80211.c       | 13 +++++++++++++
 3 files changed, 18 insertions(+)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 97c16d4ff127..6bc490108303 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -901,6 +901,7 @@ struct cfg80211_bitrate_mask {
 		enum nl80211_eht_gi eht_gi;
 		enum nl80211_he_ltf he_ltf;
 		enum nl80211_eht_ltf eht_ltf;
+		bool nonht_dup_6ghz;
 	} control[NUM_NL80211_BANDS];
 };
 
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 020387d76412..d8fefefc11a9 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -5900,6 +5900,9 @@ enum nl80211_key_attributes {
  *	see &struct nl80211_txrate_eht
  * @NL80211_TXRATE_EHT_GI: configure EHT GI, (u8, see &enum nl80211_eht_gi)
  * @NL80211_TXRATE_EHT_LTF: configure EHT LTF, (u8, see &enum nl80211_eht_ltf)
+ * @NL80211_TXRATE_6GHZ_NON_HT_DUP: configure 6 GHz non-HT duplicate Beacon
+ *	transmission. This flag is applicable only in Beacon TX rate setting
+ *	and must be accompanied by a non-HT (legacy) Beacon rate.
  * @__NL80211_TXRATE_AFTER_LAST: internal
  * @NL80211_TXRATE_MAX: highest TX rate attribute
  */
@@ -5915,6 +5918,7 @@ enum nl80211_tx_rate_attributes {
 	NL80211_TXRATE_EHT,
 	NL80211_TXRATE_EHT_GI,
 	NL80211_TXRATE_EHT_LTF,
+	NL80211_TXRATE_6GHZ_NON_HT_DUP,
 
 	/* keep last */
 	__NL80211_TXRATE_AFTER_LAST,
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 44f2bad08670..cb4752fc38a0 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -569,6 +569,7 @@ static const struct nla_policy nl80211_txattr_policy[NL80211_TXRATE_MAX + 1] = {
 	[NL80211_TXRATE_EHT_LTF] = NLA_POLICY_RANGE(NLA_U8,
 						   NL80211_RATE_INFO_EHT_1XLTF,
 						   NL80211_RATE_INFO_EHT_8XLTF),
+	[NL80211_TXRATE_6GHZ_NON_HT_DUP] = { .type = NLA_FLAG },
 
 };
 
@@ -6303,6 +6304,14 @@ static int nl80211_parse_tx_bitrate_mask(struct genl_info *info,
 			mask->control[band].eht_ltf =
 				nla_get_u8(tb[NL80211_TXRATE_EHT_LTF]);
 
+		if (tb[NL80211_TXRATE_6GHZ_NON_HT_DUP]) {
+			if (band != NL80211_BAND_6GHZ ||
+			    (wdev->iftype != NL80211_IFTYPE_AP &&
+			     wdev->iftype != NL80211_IFTYPE_P2P_GO))
+				return -EINVAL;
+			mask->control[band].nonht_dup_6ghz = true;
+		}
+
 		if (mask->control[band].legacy == 0) {
 			/* don't allow empty legacy rates if HT, VHT, HE or EHT
 			 * are not even supported.
@@ -6344,6 +6353,7 @@ static int validate_beacon_tx_rate(struct cfg80211_registered_device *rdev,
 {
 	u32 count_ht, count_vht, count_he, count_eht, i;
 	u32 rate = beacon_rate->control[band].legacy;
+	bool nonht_dup = beacon_rate->control[band].nonht_dup_6ghz;
 
 	/* Allow only one rate */
 	if (hweight32(rate) > 1)
@@ -6405,6 +6415,9 @@ static int validate_beacon_tx_rate(struct cfg80211_registered_device *rdev,
 	    (!rate && !count_ht && !count_vht && !count_he && !count_eht))
 		return -EINVAL;
 
+	if (nonht_dup && !rate)
+		return -EINVAL;
+
 	if (rate &&
 	    !wiphy_ext_feature_isset(&rdev->wiphy,
 				     NL80211_EXT_FEATURE_BEACON_RATE_LEGACY))

---
base-commit: 6c5fc504d0d6934132637aa3db4b9b58148eaa78
change-id: 20260805-dup-beacon-0d074e15ecf7