[PATCH v2 1/2] wifi: ath9k_htc: derive the PHY error filter bits from software state

ath9k_htc_calcrxfilter() calls ath9k_hw_getrxfilter(), which reads
AR_RX_FILTER and AR_PHY_ERR back from the device, to preserve the PHY
error bits that a spectral scan may have set. On USB each read is a
WMI round trip. When the AR_RX_FILTER read times out ath9k_regread()
returns -1, the recalculated filter has PHYERR and PHYRADAR set with no
scan running, and the device forwards every PHY error frame to the
host until the next recalculation.

The spectral mode is already tracked in priv->spec_priv. Set the two
bits from it and drop the readback. This saves two round trips per
recalculation, and the bits are now cleared when the scan is disabled
instead of staying set until the next reset. The bits still go through
ath9k_hw_setrxfilter(), so AR_PHY_ERR and AR_RXCFG_ZLFDMA follow the
filter as before.

Assisted-by: Claude:claude-fable-5-1
Signed-off-by: Nerijus Bendžiūnas <redacted>
---
 drivers/net/wireless/ath/ath9k/htc_drv_txrx.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c b/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c
index bed7ea2425a0..299064a7fa49 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c

@@ -868,14 +868,14 @@ int ath9k_htc_cabq_setup(struct ath9k_htc_priv *priv)
  */
 u32 ath9k_htc_calcrxfilter(struct ath9k_htc_priv *priv)
 {
-#define	RX_FILTER_PRESERVE (ATH9K_RX_FILTER_PHYERR | ATH9K_RX_FILTER_PHYRADAR)
-
 	struct ath_hw *ah = priv->ah;
 	u32 rfilt;
 
-	rfilt = (ath9k_hw_getrxfilter(ah) & RX_FILTER_PRESERVE)
-		| ATH9K_RX_FILTER_UCAST | ATH9K_RX_FILTER_BCAST
-		| ATH9K_RX_FILTER_MCAST;
+	rfilt = ATH9K_RX_FILTER_UCAST | ATH9K_RX_FILTER_BCAST |
+		ATH9K_RX_FILTER_MCAST;
+
+	if (priv->spec_priv.spectral_mode != SPECTRAL_DISABLED)
+		rfilt |= ATH9K_RX_FILTER_PHYRADAR | ATH9K_RX_FILTER_PHYERR;
 
 	if (priv->rxfilter & FIF_PROBE_REQ)
 		rfilt |= ATH9K_RX_FILTER_PROBEREQ;

@@ -906,8 +906,6 @@ u32 ath9k_htc_calcrxfilter(struct ath9k_htc_priv *priv)
 		rfilt |= ATH9K_RX_FILTER_MCAST_BCAST_ALL;
 
 	return rfilt;
-
-#undef RX_FILTER_PRESERVE
 }
 
 /*

-- 
2.55.0