Add support for Linux 4.12

In preparation to add HE support Linux 4.12 separates flags for
bandwidth and encoding in mac80211. Use the new flags as appropriate.

To avoid using LINUX_VERSION_CODE, as requested, pull a stunt using the
definition of RX_ENC_FLAG_STBC_SHIFT which was added in 4.12 as well to
check for the version thereby obfuscating what is going on.

URL: #156
Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>

hif/pcie/rx.c

@@ -225,6 +225,29 @@ static inline void pcie_rx_prepare_status(struct pcie_rx_desc *pdesc,
 	gi = (rate & MWL_RX_RATE_GI_MASK) >> MWL_RX_RATE_GI_SHIFT;
 	rt = (rate & MWL_RX_RATE_RT_MASK) >> MWL_RX_RATE_RT_SHIFT;
 
+#ifdef RX_ENC_FLAG_STBC_SHIFT
+	switch (format) {
+	case RX_RATE_INFO_FORMAT_11N:
+		status->encoding = RX_ENC_HT;
+		if (bw == RX_RATE_INFO_HT40)
+			status->bw = RATE_INFO_BW_40;
+		if (gi == RX_RATE_INFO_SHORT_INTERVAL)
+			status->enc_flags |= RX_ENC_FLAG_SHORT_GI;
+		break;
+	case RX_RATE_INFO_FORMAT_11AC:
+		status->encoding = RX_ENC_VHT;
+		if (bw == RX_RATE_INFO_HT40)
+			status->bw = RATE_INFO_BW_40;
+		if (bw == RX_RATE_INFO_HT80)
+			status->bw = RATE_INFO_BW_80;
+		if (bw == RX_RATE_INFO_HT160)
+			status->bw = RATE_INFO_BW_160;
+		if (gi == RX_RATE_INFO_SHORT_INTERVAL)
+			status->enc_flags |= RX_ENC_FLAG_SHORT_GI;
+		status->nss = (nss + 1);
+		break;
+	}
+#else
 	switch (format) {
 	case RX_RATE_INFO_FORMAT_11N:
 		status->flag |= RX_FLAG_HT;
@@ -246,21 +269,31 @@ static inline void pcie_rx_prepare_status(struct pcie_rx_desc *pdesc,
 		status->vht_nss = (nss + 1);
 		break;
 	}
-
+#endif
 	status->rate_idx = rt;
 
 	if (pdesc->channel > BAND_24_CHANNEL_NUM) {
 		status->band = NL80211_BAND_5GHZ;
+#ifdef RX_ENC_FLAG_STBC_SHIFT
+		if ((!(status->encoding == RX_ENC_HT)) &&
+		    (!(status->encoding == RX_ENC_VHT))) {
+#else
 		if ((!(status->flag & RX_FLAG_HT)) &&
 		    (!(status->flag & RX_FLAG_VHT))) {
+#endif
 			status->rate_idx -= 5;
 			if (status->rate_idx >= BAND_50_RATE_NUM)
 				status->rate_idx = BAND_50_RATE_NUM - 1;
 		}
 	} else {
 		status->band = NL80211_BAND_2GHZ;
+#ifdef RX_ENC_FLAG_STBC_SHIFT
+		if ((!(status->encoding == RX_ENC_HT)) &&
+		    (!(status->encoding == RX_ENC_VHT))) {
+#else
 		if ((!(status->flag & RX_FLAG_HT)) &&
 		    (!(status->flag & RX_FLAG_VHT))) {
+#endif
 			if (status->rate_idx >= BAND_24_RATE_NUM)
 				status->rate_idx = BAND_24_RATE_NUM - 1;
 		}