From ac55d2fe0576d272c4a98ed9dfb87b1cca29486e Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg@intel.com>
Date: Thu, 10 May 2012 09:09:10 +0200
Subject: mac80211: (selectively) add HT details in radiotap

Add a flag for the HT format (mixed vs. greenfield)
to allow drivers to report that on receive. Not all
drivers will do that though, so allow drivers to set
which radiotap MCS details they report.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 60e3766..1937c7d 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -667,6 +667,9 @@ ieee80211_tx_info_clear_status(struct ieee80211_tx_info *info)
  * @RX_FLAG_SHORT_GI: Short guard interval was used
  * @RX_FLAG_NO_SIGNAL_VAL: The signal strength value is not present.
  *	Valid only for data frames (mainly A-MPDU)
+ * @RX_FLAG_HT_GF: This frame was received in a HT-greenfield transmission, if
+ *	the driver fills this value it should add %IEEE80211_RADIOTAP_MCS_HAVE_FMT
+ *	to hw.radiotap_mcs_details to advertise that fact
  */
 enum mac80211_rx_flags {
 	RX_FLAG_MMIC_ERROR	= 1<<0,
@@ -681,6 +684,7 @@ enum mac80211_rx_flags {
 	RX_FLAG_40MHZ		= 1<<10,
 	RX_FLAG_SHORT_GI	= 1<<11,
 	RX_FLAG_NO_SIGNAL_VAL	= 1<<12,
+	RX_FLAG_HT_GF		= 1<<13,
 };
 
 /**
@@ -1288,6 +1292,11 @@ enum ieee80211_hw_flags {
  *
  * @offchannel_tx_hw_queue: HW queue ID to use for offchannel TX
  *	(if %IEEE80211_HW_QUEUE_CONTROL is set)
+ *
+ * @radiotap_mcs_details: lists which MCS information can the HW
+ *	reports, by default it is set to _MCS, _GI and _BW but doesn't
+ *	include _FMT. Use %IEEE80211_RADIOTAP_MCS_HAVE_* values, only
+ *	adding _BW is supported today.
  */
 struct ieee80211_hw {
 	struct ieee80211_conf conf;
@@ -1309,6 +1318,7 @@ struct ieee80211_hw {
 	u8 max_rx_aggregation_subframes;
 	u8 max_tx_aggregation_subframes;
 	u8 offchannel_tx_hw_queue;
+	u8 radiotap_mcs_details;
 };
 
 /**
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index b70f7f0..f5548e9 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -596,6 +596,9 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
 	local->hw.offchannel_tx_hw_queue = IEEE80211_INVAL_HW_QUEUE;
 	local->hw.conf.long_frame_max_tx_count = wiphy->retry_long;
 	local->hw.conf.short_frame_max_tx_count = wiphy->retry_short;
+	local->hw.radiotap_mcs_details = IEEE80211_RADIOTAP_MCS_HAVE_MCS |
+					 IEEE80211_RADIOTAP_MCS_HAVE_GI |
+					 IEEE80211_RADIOTAP_MCS_HAVE_BW;
 	local->user_power_level = -1;
 	wiphy->ht_capa_mod_mask = &mac80211_ht_capa_mod_mask;
 
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index d5ac02f..489093b 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -204,14 +204,14 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
 
 	if (status->flag & RX_FLAG_HT) {
 		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_MCS);
-		*pos++ = IEEE80211_RADIOTAP_MCS_HAVE_MCS |
-			 IEEE80211_RADIOTAP_MCS_HAVE_GI |
-			 IEEE80211_RADIOTAP_MCS_HAVE_BW;
+		*pos++ = local->hw.radiotap_mcs_details;
 		*pos = 0;
 		if (status->flag & RX_FLAG_SHORT_GI)
 			*pos |= IEEE80211_RADIOTAP_MCS_SGI;
 		if (status->flag & RX_FLAG_40MHZ)
 			*pos |= IEEE80211_RADIOTAP_MCS_BW_40;
+		if (status->flag & RX_FLAG_HT_GF)
+			*pos |= IEEE80211_RADIOTAP_MCS_FMT_GF;
 		pos++;
 		*pos++ = status->rate_idx;
 	}
-- 
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