Index: sys/dev/rtwn/if_rtwn.c
===================================================================
--- sys/dev/rtwn/if_rtwn.c
+++ sys/dev/rtwn/if_rtwn.c
@@ -1054,8 +1054,6 @@
 static int
 rtwn_ra_init(struct rtwn_softc *sc)
 {
-	static const uint8_t map[] =
-	    { 2, 4, 11, 22, 12, 18, 24, 36, 48, 72, 96, 108 };
 	struct ieee80211com *ic = &sc->sc_ic;
 	struct ieee80211vap *vap = TAILQ_FIRST(&ic->ic_vaps);
 	struct ieee80211_node *ni = ieee80211_ref_node(vap->iv_bss);
@@ -1070,10 +1068,11 @@
 	maxrate = maxbasicrate = 0;
 	for (i = 0; i < rs->rs_nrates; i++) {
 		/* Convert 802.11 rate to HW rate index. */
-		for (j = 0; j < nitems(map); j++)
-			if ((rs->rs_rates[i] & IEEE80211_RATE_VAL) == map[j])
+		for (j = 0; j < nitems(ridx2rate); j++)
+			if ((rs->rs_rates[i] & IEEE80211_RATE_VAL) ==
+			    ridx2rate[j])
 				break;
-		if (j == nitems(map))	/* Unknown rate, skip. */
+		if (j == nitems(ridx2rate))	/* Unknown rate, skip. */
 			continue;
 		rates |= 1 << j;
 		if (j > maxrate)
@@ -1362,7 +1361,7 @@
 		pwdb = 100;
 	else
 		pwdb = 100 + rssi;
-	if (rate <= 3) {
+	if (rate <= RTWN_RIDX_CCK11) {
 		/* CCK gain is smaller than OFDM/MCS gain. */
 		pwdb += 6;
 		if (pwdb > 100)
@@ -1394,7 +1393,7 @@
 	uint8_t rpt;
 	int8_t rssi;
 
-	if (rate <= 3) {
+	if (rate <= RTWN_RIDX_CCK11) {
 		cck = (struct r92c_rx_cck *)physt;
 		if (sc->sc_flags & RTWN_FLAG_CCK_HIPWR) {
 			rpt = (cck->agc_rpt >> 5) & 0x3;
@@ -1506,22 +1505,7 @@
 
 		tap->wr_flags = 0;
 		if (!(rxdw3 & R92C_RXDW3_HT)) {
-			switch (rate) {
-			/* CCK. */
-			case  0: tap->wr_rate =   2; break;
-			case  1: tap->wr_rate =   4; break;
-			case  2: tap->wr_rate =  11; break;
-			case  3: tap->wr_rate =  22; break;
-			/* OFDM. */
-			case  4: tap->wr_rate =  12; break;
-			case  5: tap->wr_rate =  18; break;
-			case  6: tap->wr_rate =  24; break;
-			case  7: tap->wr_rate =  36; break;
-			case  8: tap->wr_rate =  48; break;
-			case  9: tap->wr_rate =  72; break;
-			case 10: tap->wr_rate =  96; break;
-			case 11: tap->wr_rate = 108; break;
-			}
+			tap->wr_rate = ridx2rate[rate];
 		} else if (rate >= 12) {	/* MCS0~15. */
 			/* Bit 7 set means HT MCS instead of rate. */
 			tap->wr_rate = 0x80 | (rate - 12);
@@ -1644,10 +1628,12 @@
 		/* XXX TODO: implement rate control */
 
 		/* Send RTS at OFDM24. */
-		txd->txdw4 |= htole32(SM(R92C_TXDW4_RTSRATE, 8));
+		txd->txdw4 |= htole32(SM(R92C_TXDW4_RTSRATE,
+		    RTWN_RIDX_OFDM24));
 		txd->txdw5 |= htole32(SM(R92C_TXDW5_RTSRATE_FBLIMIT, 0xf));
 		/* Send data at OFDM54. */
-		txd->txdw5 |= htole32(SM(R92C_TXDW5_DATARATE, 11));
+		txd->txdw5 |= htole32(SM(R92C_TXDW5_DATARATE,
+		    RTWN_RIDX_OFDM54));
 		txd->txdw5 |= htole32(SM(R92C_TXDW5_DATARATE_FBLIMIT, 0x1f));
 
 	} else {
@@ -1658,7 +1644,7 @@
 
 		/* Force CCK1. */
 		txd->txdw4 |= htole32(R92C_TXDW4_DRVRATE);
-		txd->txdw5 |= htole32(SM(R92C_TXDW5_DATARATE, 0));
+		txd->txdw5 |= htole32(SM(R92C_TXDW5_DATARATE, RTWN_RIDX_CCK1));
 	}
 	/* Set sequence number (already little endian). */
 	txd->txdseq = htole16(M_SEQNO_GET(m) % IEEE80211_SEQ_RANGE);
@@ -2582,10 +2568,10 @@
 
 	memset(power, 0, RTWN_RIDX_COUNT * sizeof(power[0]));
 	if (sc->regulatory == 0) {
-		for (ridx = 0; ridx <= 3; ridx++)
+		for (ridx = RTWN_RIDX_CCK1; ridx <= RTWN_RIDX_CCK11; ridx++)
 			power[ridx] = base->pwr[0][ridx];
 	}
-	for (ridx = 4; ridx < RTWN_RIDX_COUNT; ridx++) {
+	for (ridx = RTWN_RIDX_OFDM6; ridx < RTWN_RIDX_COUNT; ridx++) {
 		if (sc->regulatory == 3) {
 			power[ridx] = base->pwr[0][ridx];
 			/* Apply vendor limits. */
@@ -2605,7 +2591,7 @@
 
 	/* Compute per-CCK rate Tx power. */
 	cckpow = rom->cck_tx_pwr[chain][group];
-	for (ridx = 0; ridx <= 3; ridx++) {
+	for (ridx = RTWN_RIDX_CCK1; ridx <= RTWN_RIDX_CCK11; ridx++) {
 		power[ridx] += cckpow;
 		if (power[ridx] > R92C_MAX_TX_PWR)
 			power[ridx] = R92C_MAX_TX_PWR;
@@ -2623,7 +2609,7 @@
 	diff = rom->ofdm_tx_pwr_diff[group];
 	diff = (diff >> (chain * 4)) & 0xf;
 	ofdmpow = htpow + diff;	/* HT->OFDM correction. */
-	for (ridx = 4; ridx <= 11; ridx++) {
+	for (ridx = RTWN_RIDX_OFDM6; ridx <= RTWN_RIDX_OFDM54; ridx++) {
 		power[ridx] += ofdmpow;
 		if (power[ridx] > R92C_MAX_TX_PWR)
 			power[ridx] = R92C_MAX_TX_PWR;
@@ -2644,7 +2630,7 @@
 	if (sc->sc_debug >= 4) {
 		/* Dump per-rate Tx power values. */
 		printf("Tx power for chain %d:\n", chain);
-		for (ridx = 0; ridx < RTWN_RIDX_COUNT; ridx++)
+		for (ridx = RTWN_RIDX_CCK1; ridx < RTWN_RIDX_COUNT; ridx++)
 			printf("Rate %d = %u\n", ridx, power[ridx]);
 	}
 #endif
Index: sys/dev/rtwn/if_rtwnreg.h
===================================================================
--- sys/dev/rtwn/if_rtwnreg.h
+++ sys/dev/rtwn/if_rtwnreg.h
@@ -1162,6 +1162,18 @@
 	uint32_t	reserved[4];
 } __packed __attribute__((aligned(4)));
 
+static const uint8_t ridx2rate[] =
+	{ 2, 4, 11, 22, 12, 18, 24, 36, 48, 72, 96, 108 };
+
+/* HW rate indices. */
+#define RTWN_RIDX_CCK1		0
+#define RTWN_RIDX_CCK11		3
+#define RTWN_RIDX_OFDM6		4
+#define RTWN_RIDX_OFDM24	8
+#define RTWN_RIDX_OFDM54	11
+
+#define RTWN_RIDX_COUNT		28
+
 
 /*
  * Driver definitions.
@@ -1188,8 +1200,6 @@
 #define RTWN_RXBUFSZ	(16 * 1024)
 #define RTWN_TXBUFSZ	(sizeof(struct r92c_tx_desc) + IEEE80211_MAX_LEN)
 
-#define RTWN_RIDX_COUNT	28
-
 #define RTWN_TX_TIMEOUT	5000	/* ms */
 
 #define RTWN_LED_LINK	0