ieee80211: add new VHT capability fields/parsing

IEEE 802.11-2016 extended the VHT capability fields to allow
indicating the number of spatial streams depending on the
actually used bandwidth, add support for decoding this.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 33 insertions, 2 deletions

diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index 17ea51d088ae..280600a10111 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -1460,13 +1460,16 @@ struct ieee80211_ht_operation {
  *	STA can receive. Rate expressed in units of 1 Mbps.
  *	If this field is 0 this value should not be used to
  *	consider the highest RX data rate supported.
- *	The top 3 bits of this field are reserved.
+ *	The top 3 bits of this field indicate the Maximum NSTS,total
+ *	(a beamformee capability.)
  * @tx_mcs_map: TX MCS map 2 bits for each stream, total 8 streams
  * @tx_highest: Indicates highest long GI VHT PPDU data rate
  *	STA can transmit. Rate expressed in units of 1 Mbps.
  *	If this field is 0 this value should not be used to
  *	consider the highest TX data rate supported.
- *	The top 3 bits of this field are reserved.
+ *	The top 2 bits of this field are reserved, the
+ *	3rd bit from the top indiciates VHT Extended NSS BW
+ *	Capability.
  */
 struct ieee80211_vht_mcs_info {
 	__le16 rx_mcs_map;
@@ -1475,6 +1478,13 @@ struct ieee80211_vht_mcs_info {
 	__le16 tx_highest;
 } __packed;
 
+/* for rx_highest */
+#define IEEE80211_VHT_MAX_NSTS_TOTAL_SHIFT	13
+#define IEEE80211_VHT_MAX_NSTS_TOTAL_MASK	(7 << IEEE80211_VHT_MAX_NSTS_TOTAL_SHIFT)
+
+/* for tx_highest */
+#define IEEE80211_VHT_EXT_NSS_BW_CAPABLE	(1 << 13)
+
 /**
  * enum ieee80211_vht_mcs_support - VHT MCS support definitions
  * @IEEE80211_VHT_MCS_SUPPORT_0_7: MCSes 0-7 are supported for the
@@ -1650,6 +1660,7 @@ struct ieee80211_mu_edca_param_set {
 #define IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ		0x00000004
 #define IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ	0x00000008
 #define IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_MASK			0x0000000C
+#define IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_SHIFT			2
 #define IEEE80211_VHT_CAP_RXLDPC				0x00000010
 #define IEEE80211_VHT_CAP_SHORT_GI_80				0x00000020
 #define IEEE80211_VHT_CAP_SHORT_GI_160				0x00000040
@@ -1678,6 +1689,26 @@ struct ieee80211_mu_edca_param_set {
 #define IEEE80211_VHT_CAP_VHT_LINK_ADAPTATION_VHT_MRQ_MFB	0x0c000000
 #define IEEE80211_VHT_CAP_RX_ANTENNA_PATTERN			0x10000000
 #define IEEE80211_VHT_CAP_TX_ANTENNA_PATTERN			0x20000000
+#define IEEE80211_VHT_CAP_EXT_NSS_BW_SHIFT			30
+#define IEEE80211_VHT_CAP_EXT_NSS_BW_MASK			0xc0000000
+
+/**
+ * ieee80211_get_vht_max_nss - return max NSS for a given bandwidth/MCS
+ * @cap: VHT capabilities of the peer
+ * @bw: bandwidth to use
+ * @mcs: MCS index to use
+ * @ext_nss_bw_capable: indicates whether or not the local transmitter
+ *	(rate scaling algorithm) can deal with the new logic
+ *	(dot11VHTExtendedNSSBWCapable)
+ *
+ * Due to the VHT Extended NSS Bandwidth Support, the maximum NSS can
+ * vary for a given BW/MCS. This function parses the data.
+ *
+ * Note: This function is exported by cfg80211.
+ */
+int ieee80211_get_vht_max_nss(struct ieee80211_vht_cap *cap,
+			      enum ieee80211_vht_chanwidth bw,
+			      int mcs, bool ext_nss_bw_capable);
 
 /* 802.11ax HE MAC capabilities */
 #define IEEE80211_HE_MAC_CAP0_HTC_HE				0x01