Let iwx(4) firmware decide which Tx rate to use.

The firmware will notify the driver when it decides to change Tx rate.
Based on those notifications the driver updates the value displayed by
ifconfig. This is similar to how bwfm(4) and urtwn(4) handle this.

Offloading Tx rate selection should allow us to eventually delete AMRR/MiRA
support code from iwx(4). That code is disabled for now, not yet deleted.

For now, the driver restricts firmware Tx rate selection to 11n/20MHz mode
because that's what net80211 can support.

1 files changed, 146 insertions, 6 deletions

diff --git a/sys/dev/pci/if_iwx.c b/sys/dev/pci/if_iwx.c
index b5cc5abfc62..802619b1f16 100644
--- a/sys/dev/pci/if_iwx.c
+++ b/sys/dev/pci/if_iwx.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_iwx.c,v 1.26 2020/06/11 11:27:44 stsp Exp $	*/
+/*	$OpenBSD: if_iwx.c,v 1.27 2020/06/17 08:18:21 stsp Exp $	*/
 
 /*
  * Copyright (c) 2014, 2016 genua gmbh <info@genua.de>
@@ -409,6 +409,9 @@ int	iwx_scan(struct iwx_softc *);
 int	iwx_bgscan(struct ieee80211com *);
 int	iwx_umac_scan_abort(struct iwx_softc *);
 int	iwx_scan_abort(struct iwx_softc *);
+int	iwx_rs_rval2idx(uint8_t);
+uint16_t iwx_rs_ht_rates(struct iwx_softc *, struct ieee80211_node *, int);
+int	iwx_rs_init(struct iwx_softc *, struct iwx_node *);
 int	iwx_enable_data_tx_queues(struct iwx_softc *);
 int	iwx_auth(struct iwx_softc *);
 int	iwx_deauth(struct iwx_softc *);
@@ -3775,6 +3778,7 @@ iwx_rx_tx_cmd_single(struct iwx_softc *sc, struct iwx_rx_packet *pkt,
 			in->in_mn.retries += tx_resp->failure_frame;
 		if (txfail)
 			in->in_mn.txfail += tx_resp->frame_count;
+#if 0
 		if (ic->ic_state == IEEE80211_S_RUN && !in->ht_force_cck) {
 			int otxmcs = ni->ni_txmcs;
 
@@ -3785,6 +3789,7 @@ iwx_rx_tx_cmd_single(struct iwx_softc *sc, struct iwx_rx_packet *pkt,
 			    otxmcs == 0 && ni->ni_txmcs == 0)
 				iwx_enable_ht_cck_fallback(sc, in);
 		}
+#endif
 	}
 
 	if (txfail)
@@ -4294,10 +4299,13 @@ iwx_tx_fill_cmd(struct iwx_softc *sc, struct iwx_node *in,
 	    type != IEEE80211_FC0_TYPE_DATA) {
 		/* for non-data, use the lowest supported rate */
 		ridx = min_ridx;
+		flags |= IWX_TX_FLAGS_CMD_RATE;
 	} else if (ic->ic_fixed_mcs != -1) {
 		ridx = sc->sc_fixed_ridx;
+		flags |= IWX_TX_FLAGS_CMD_RATE;
 	} else if (ic->ic_fixed_rate != -1) {
 		ridx = sc->sc_fixed_ridx;
+		flags |= IWX_TX_FLAGS_CMD_RATE;
 	} else if ((ni->ni_flags & IEEE80211_NODE_HT) && !in->ht_force_cck) {
 		ridx = iwx_mcs2ridx[ni->ni_txmcs];
 	} else {
@@ -4308,7 +4316,7 @@ iwx_tx_fill_cmd(struct iwx_softc *sc, struct iwx_node *in,
 			ridx = min_ridx;
 	}
 
-	flags = (IWX_TX_FLAGS_CMD_RATE | IWX_TX_FLAGS_ENCRYPT_DIS);
+	flags |= IWX_TX_FLAGS_ENCRYPT_DIS;
 	if ((ic->ic_flags & IEEE80211_F_RSNON) &&
 	    ni->ni_rsn_supp_state == RSNA_SUPP_PTKNEGOTIATING)
 		flags |= IWX_TX_FLAGS_HIGH_PRI;
@@ -5742,6 +5750,120 @@ iwx_enable_data_tx_queues(struct iwx_softc *sc)
 }
 
 int
+iwx_rs_rval2idx(uint8_t rval)
+{
+	/* Firmware expects indices which match our 11g rate set. */
+	const struct ieee80211_rateset *rs = &ieee80211_std_rateset_11g;
+	int i;
+
+	for (i = 0; i < rs->rs_nrates; i++) {
+		if ((rs->rs_rates[i] & IEEE80211_RATE_VAL) == rval)
+			return i;
+	}
+
+	return -1;
+}
+
+uint16_t
+iwx_rs_ht_rates(struct iwx_softc *sc, struct ieee80211_node *ni, int rsidx)
+{
+	struct ieee80211com *ic = &sc->sc_ic;
+	const struct ieee80211_ht_rateset *rs;
+	uint16_t htrates = 0;
+	int mcs;
+
+	rs = &ieee80211_std_ratesets_11n[rsidx];
+	for (mcs = rs->min_mcs; mcs <= rs->max_mcs; mcs++) {
+		if (!isset(ni->ni_rxmcs, mcs) ||
+		    !isset(ic->ic_sup_mcs, mcs))
+			continue;
+		htrates |= (1 << (mcs - rs->min_mcs));
+	}
+
+	return htrates;
+}
+
+int
+iwx_rs_init(struct iwx_softc *sc, struct iwx_node *in)
+{
+	struct ieee80211_node *ni = &in->in_ni;
+	struct ieee80211_rateset *rs = &ni->ni_rates;
+	struct iwx_tlc_config_cmd cfg_cmd;
+	uint32_t cmd_id;
+	int i;
+
+	memset(&cfg_cmd, 0, sizeof(cfg_cmd));
+
+	for (i = 0; i < rs->rs_nrates; i++) {
+		uint8_t rval = rs->rs_rates[i] & IEEE80211_RATE_VAL;
+		int idx = iwx_rs_rval2idx(rval);
+		if (idx == -1)
+			return EINVAL;
+		cfg_cmd.non_ht_rates |= (1 << idx);
+	}
+
+	if (ni->ni_flags & IEEE80211_NODE_HT) {
+		cfg_cmd.mode = IWX_TLC_MNG_MODE_HT;
+		cfg_cmd.ht_rates[IWX_TLC_NSS_1][IWX_TLC_HT_BW_NONE_160] =
+		    iwx_rs_ht_rates(sc, ni, IEEE80211_HT_RATESET_SISO);
+		cfg_cmd.ht_rates[IWX_TLC_NSS_2][IWX_TLC_HT_BW_NONE_160] =
+		    iwx_rs_ht_rates(sc, ni, IEEE80211_HT_RATESET_MIMO2);
+	} else
+		cfg_cmd.mode = IWX_TLC_MNG_MODE_NON_HT;
+
+	cfg_cmd.sta_id = IWX_STATION_ID;
+	cfg_cmd.max_ch_width = IWX_RATE_MCS_CHAN_WIDTH_20;
+	cfg_cmd.chains = IWX_TLC_MNG_CHAIN_A_MSK | IWX_TLC_MNG_CHAIN_B_MSK;
+	cfg_cmd.max_mpdu_len = IEEE80211_MAX_LEN;
+	if (ieee80211_node_supports_ht_sgi20(ni))
+		cfg_cmd.sgi_ch_width_supp = (1 << IWX_TLC_MNG_CH_WIDTH_20MHZ);
+
+	cmd_id = iwx_cmd_id(IWX_TLC_MNG_CONFIG_CMD, IWX_DATA_PATH_GROUP, 0);
+	return iwx_send_cmd_pdu(sc, cmd_id, IWX_CMD_ASYNC, sizeof(cfg_cmd),
+	    &cfg_cmd);
+}
+
+void
+iwx_rs_update(struct iwx_softc *sc, struct iwx_tlc_update_notif *notif)
+{
+	struct ieee80211com *ic = &sc->sc_ic;
+	struct ieee80211_node *ni = ic->ic_bss;
+	struct ieee80211_rateset *rs = &ni->ni_rates;
+	uint32_t rate_n_flags;
+	int i;
+
+	if (notif->sta_id != IWX_STATION_ID ||
+	    (le32toh(notif->flags) & IWX_TLC_NOTIF_FLAG_RATE) == 0)
+		return;
+
+	rate_n_flags = le32toh(notif->rate);
+	if (rate_n_flags & IWX_RATE_MCS_HT_MSK) {
+		ni->ni_txmcs = (rate_n_flags &
+		    (IWX_RATE_HT_MCS_RATE_CODE_MSK |
+		    IWX_RATE_HT_MCS_NSS_MSK));
+	} else {
+		uint8_t plcp = (rate_n_flags & IWX_RATE_LEGACY_RATE_MSK);
+		uint8_t rval = 0;
+		for (i = IWX_RATE_1M_INDEX; i < nitems(iwx_rates); i++) {
+			if (iwx_rates[i].plcp == plcp) {
+				rval = iwx_rates[i].rate;
+				break;
+			}
+		}
+		if (rval) {
+			uint8_t rv;
+			for (i = 0; i < rs->rs_nrates; i++) {
+				rv = rs->rs_rates[i] & IEEE80211_RATE_VAL;
+				if (rv == rval) {
+					ni->ni_txrate = i;
+					break;
+				}
+			}
+		}
+	}
+}
+
+int
 iwx_auth(struct iwx_softc *sc)
 {
 	struct ieee80211com *ic = &sc->sc_ic;
@@ -6025,11 +6147,17 @@ iwx_run(struct iwx_softc *sc)
 	in->in_ni.ni_txrate = 0;
 	in->in_ni.ni_txmcs = 0;
 
-	if (isset(sc->sc_enabled_capa, IWX_UCODE_TLV_CAPA_TLC_OFFLOAD))
-		DPRINTF(("%s: TODO: Enable firmware rate scaling?\n",
-		    DEVNAME(sc)));
-
+	if (isset(sc->sc_enabled_capa, IWX_UCODE_TLV_CAPA_TLC_OFFLOAD)) {
+		err = iwx_rs_init(sc, in);
+		if (err) {
+			printf("%s: could not init rate scaling (error %d)\n",
+			    DEVNAME(sc), err);
+			return err;
+		}
+	}
+#if 0
 	timeout_add_msec(&sc->sc_calib_to, 500);
+#endif
 	return 0;
 }
 
@@ -7451,6 +7579,18 @@ iwx_rx_pkt(struct iwx_softc *sc, struct iwx_rx_data *data, struct mbuf_list *ml)
 		case IWX_WIDE_ID(IWX_DATA_PATH_GROUP, IWX_RX_NO_DATA_NOTIF):
 			break; /* happens in monitor mode; ignore for now */
 
+		case IWX_WIDE_ID(IWX_DATA_PATH_GROUP, IWX_TLC_MNG_CONFIG_CMD):
+			break;
+
+		case IWX_WIDE_ID(IWX_DATA_PATH_GROUP,
+		    IWX_TLC_MNG_UPDATE_NOTIF): {
+			struct iwx_tlc_update_notif *notif;
+			SYNC_RESP_STRUCT(notif, pkt);
+			if (iwx_rx_packet_payload_len(pkt) == sizeof(*notif))
+				iwx_rs_update(sc, notif);
+			break;
+		}
+
 		default:
 			handled = 0;
 			printf("%s: unhandled firmware response 0x%x/0x%x "