staging: brcm80211: fill in proper rx rate in mac80211 rx status

The brcmsmac driver supports different rates on 5GHz but this is not
taken into account when providing the rate index in the receive
status information passed to mac80211.
Reviewed-by: NRoland Vossen <rvossen@broadcom.com>
Reviewed-by: NPieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: NHenry Ptasinski <henryp@broadcom.com>
Signed-off-by: NArend van Spriel <arend@broadcom.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/brcm80211/brcmsmac/mac80211_if.c

@@ -971,6 +971,10 @@ static struct ieee80211_channel brcms_5ghz_nphy_chantable[] = {
 	.hw_value = (rate100m / 5), \
 }
 
+/*
+ * The rate table is used for both 2.4G and 5G rates. The
+ * latter being a subset as it does not support CCK rates.
+ */
 static struct ieee80211_rate legacy_ratetable[] = {
 	RATE(10, 0),
 	RATE(20, IEEE80211_RATE_SHORT_PREAMBLE),
@@ -1012,8 +1016,9 @@ static struct ieee80211_supported_band brcms_band_5GHz_nphy = {
 	.band = IEEE80211_BAND_5GHZ,
 	.channels = brcms_5ghz_nphy_chantable,
 	.n_channels = ARRAY_SIZE(brcms_5ghz_nphy_chantable),
-	.bitrates = legacy_ratetable + 4,
-	.n_bitrates = ARRAY_SIZE(legacy_ratetable) - 4,
+	.bitrates = legacy_ratetable + BRCMS_LEGACY_5G_RATE_OFFSET,
+	.n_bitrates = ARRAY_SIZE(legacy_ratetable) -
+			BRCMS_LEGACY_5G_RATE_OFFSET,
 	.ht_cap = {
 		   .cap = IEEE80211_HT_CAP_GRN_FLD | IEEE80211_HT_CAP_SGI_20 |
 			  IEEE80211_HT_CAP_SGI_40 |

drivers/staging/brcm80211/brcmsmac/mac80211_if.h

@@ -20,6 +20,12 @@
 #include <linux/timer.h>
 #include <linux/interrupt.h>
 
+/*
+ * Starting index for 5G rates in the
+ * legacy rate table.
+ */
+#define BRCMS_LEGACY_5G_RATE_OFFSET	4
+
 /* softmac ioctl definitions */
 #define BRCMS_SET_SHORTSLOT_OVERRIDE		146
 

drivers/staging/brcm80211/brcmsmac/main.c

@@ -8252,6 +8252,14 @@ prep_mac80211_status(struct brcms_c_info *wlc, struct d11rxhdr *rxh,
 			wiphy_err(wlc->wiphy, "%s: Unknown rate\n", __func__);
 		}
 
+		/*
+		 * For 5GHz, we should decrease the index as it is
+		 * a subset of the 2.4G rates. See bitrates field
+		 * of brcms_band_5GHz_nphy (in mac80211_if.c).
+		 */
+		if (rx_status->band == IEEE80211_BAND_5GHZ)
+			rx_status->rate_idx -= BRCMS_LEGACY_5G_RATE_OFFSET;
+
 		/* Determine short preamble and rate_idx */
 		preamble = 0;
 		if (IS_CCK(rspec)) {