wifi: mac80211: rework RX timestamp flags

We only have a single flag free, and before using that for
another mactime flag, instead refactor the mactime flags
to use a 2-bit field.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Gregory Greenman <gregory.greenman@intel.com>
Reviewed-by: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20231220133549.d0e664832d14.I20c8900106f9bf81316bed778b1e3ce145785274@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/ath/ath10k/htt_rx.c

@@ -1295,7 +1295,7 @@ static void ath10k_htt_rx_h_ppdu(struct ath10k *ar,
 		status->encoding = RX_ENC_LEGACY;
 		status->bw = RATE_INFO_BW_20;
 
-		status->flag &= ~RX_FLAG_MACTIME_END;
+		status->flag &= ~RX_FLAG_MACTIME;
 		status->flag |= RX_FLAG_NO_SIGNAL_VAL;
 
 		status->flag &= ~(RX_FLAG_AMPDU_IS_LAST);

include/net/mac80211.h

@@ -1355,6 +1355,9 @@ ieee80211_tx_info_clear_status(struct ieee80211_tx_info *info)
  *	the frame.
  * @RX_FLAG_FAILED_PLCP_CRC: Set this flag if the PCLP check failed on
  *	the frame.
+ * @RX_FLAG_MACTIME: The timestamp passed in the RX status (@mactime
+ *	field) is valid if this field is non-zero, and the position
+ *	where the timestamp was sampled depends on the value.
  * @RX_FLAG_MACTIME_START: The timestamp passed in the RX status (@mactime
  *	field) is valid and contains the time the first symbol of the MPDU
  *	was received. This is useful in monitor mode and for proper IBSS
@@ -1434,12 +1437,12 @@ ieee80211_tx_info_clear_status(struct ieee80211_tx_info *info)
 enum mac80211_rx_flags {
 	RX_FLAG_MMIC_ERROR		= BIT(0),
 	RX_FLAG_DECRYPTED		= BIT(1),
-	RX_FLAG_MACTIME_PLCP_START	= BIT(2),
+	RX_FLAG_ONLY_MONITOR		= BIT(2),
 	RX_FLAG_MMIC_STRIPPED		= BIT(3),
 	RX_FLAG_IV_STRIPPED		= BIT(4),
 	RX_FLAG_FAILED_FCS_CRC		= BIT(5),
 	RX_FLAG_FAILED_PLCP_CRC 	= BIT(6),
-	RX_FLAG_MACTIME_START		= BIT(7),
+	/* one free bit at 7 */
 	RX_FLAG_NO_SIGNAL_VAL		= BIT(8),
 	RX_FLAG_AMPDU_DETAILS		= BIT(9),
 	RX_FLAG_PN_VALIDATED		= BIT(10),
@@ -1448,8 +1451,10 @@ enum mac80211_rx_flags {
 	RX_FLAG_AMPDU_IS_LAST		= BIT(13),
 	RX_FLAG_AMPDU_DELIM_CRC_ERROR	= BIT(14),
 	RX_FLAG_AMPDU_DELIM_CRC_KNOWN	= BIT(15),
-	RX_FLAG_MACTIME_END		= BIT(16),
-	RX_FLAG_ONLY_MONITOR		= BIT(17),
+	RX_FLAG_MACTIME			= BIT(16) | BIT(17),
+	RX_FLAG_MACTIME_PLCP_START	= 1 << 16,
+	RX_FLAG_MACTIME_START		= 2 << 16,
+	RX_FLAG_MACTIME_END		= 3 << 16,
 	RX_FLAG_SKIP_MONITOR		= BIT(18),
 	RX_FLAG_AMSDU_MORE		= BIT(19),
 	RX_FLAG_RADIOTAP_TLV_AT_END	= BIT(20),

net/mac80211/ieee80211_i.h

@@ -1776,10 +1776,7 @@ static inline bool txq_has_queue(struct ieee80211_txq *txq)
 static inline bool
 ieee80211_have_rx_timestamp(struct ieee80211_rx_status *status)
 {
-	WARN_ON_ONCE(status->flag & RX_FLAG_MACTIME_START &&
-		     status->flag & RX_FLAG_MACTIME_END);
-	return !!(status->flag & (RX_FLAG_MACTIME_START | RX_FLAG_MACTIME_END |
-				  RX_FLAG_MACTIME_PLCP_START));
+	return status->flag & RX_FLAG_MACTIME;
 }
 
 void ieee80211_vif_inc_num_mcast(struct ieee80211_sub_if_data *sdata);

net/mac80211/util.c

@@ -4176,6 +4176,7 @@ u64 ieee80211_calculate_rx_timestamp(struct ieee80211_local *local,
 				     unsigned int mpdu_offset)
 {
 	u64 ts = status->mactime;
+	bool mactime_plcp_start;
 	struct rate_info ri;
 	u16 rate;
 	u8 n_ltf;
@@ -4183,6 +4184,9 @@ u64 ieee80211_calculate_rx_timestamp(struct ieee80211_local *local,
 	if (WARN_ON(!ieee80211_have_rx_timestamp(status)))
 		return 0;
 
+	mactime_plcp_start = (status->flag & RX_FLAG_MACTIME) ==
+				RX_FLAG_MACTIME_PLCP_START;
+
 	memset(&ri, 0, sizeof(ri));
 
 	ri.bw = status->bw;
@@ -4197,7 +4201,7 @@ u64 ieee80211_calculate_rx_timestamp(struct ieee80211_local *local,
 		if (status->enc_flags & RX_ENC_FLAG_SHORT_GI)
 			ri.flags |= RATE_INFO_FLAGS_SHORT_GI;
 		/* TODO/FIXME: is this right? handle other PPDUs */
-		if (status->flag & RX_FLAG_MACTIME_PLCP_START) {
+		if (mactime_plcp_start) {
 			mpdu_offset += 2;
 			ts += 36;
 		}
@@ -4214,7 +4218,7 @@ u64 ieee80211_calculate_rx_timestamp(struct ieee80211_local *local,
 		 * See P802.11ax_D6.0, section 27.3.4 for
 		 * VHT PPDU format.
 		 */
-		if (status->flag & RX_FLAG_MACTIME_PLCP_START) {
+		if (mactime_plcp_start) {
 			mpdu_offset += 2;
 			ts += 36;
 
@@ -4238,7 +4242,7 @@ u64 ieee80211_calculate_rx_timestamp(struct ieee80211_local *local,
 		 * See P802.11REVmd_D3.0, section 19.3.2 for
 		 * HT PPDU format.
 		 */
-		if (status->flag & RX_FLAG_MACTIME_PLCP_START) {
+		if (mactime_plcp_start) {
 			mpdu_offset += 2;
 			if (status->enc_flags & RX_ENC_FLAG_HT_GF)
 				ts += 24;
@@ -4266,7 +4270,7 @@ u64 ieee80211_calculate_rx_timestamp(struct ieee80211_local *local,
 		 * See P802.11REVmd_D3.0, section 21.3.2 for
 		 * VHT PPDU format.
 		 */
-		if (status->flag & RX_FLAG_MACTIME_PLCP_START) {
+		if (mactime_plcp_start) {
 			mpdu_offset += 2;
 			ts += 36;
 
@@ -4288,7 +4292,7 @@ u64 ieee80211_calculate_rx_timestamp(struct ieee80211_local *local,
 		sband = local->hw.wiphy->bands[status->band];
 		ri.legacy = sband->bitrates[status->rate_idx].bitrate;
 
-		if (status->flag & RX_FLAG_MACTIME_PLCP_START) {
+		if (mactime_plcp_start) {
 			if (status->band == NL80211_BAND_5GHZ) {
 				ts += 20;
 				mpdu_offset += 2;
@@ -4310,7 +4314,7 @@ u64 ieee80211_calculate_rx_timestamp(struct ieee80211_local *local,
 		return 0;
 
 	/* rewind from end of MPDU */
-	if (status->flag & RX_FLAG_MACTIME_END)
+	if ((status->flag & RX_FLAG_MACTIME) == RX_FLAG_MACTIME_END)
 		ts -= mpdu_len * 8 * 10 / rate;
 
 	ts += mpdu_offset * 8 * 10 / rate;