summaryrefslogtreecommitdiff
path: root/net/wireless/util.c
diff options
context:
space:
mode:
authorJohannes Berg <johannes.berg@intel.com>2018-08-31 11:31:16 +0300
committerJohannes Berg <johannes.berg@intel.com>2018-09-05 11:03:14 +0300
commitb0aa75f0b1b2e6bc77128fab36c8ed87e84917cc (patch)
treea1572f027b5a2ea13af2897a530ba9cfa50af215 /net/wireless/util.c
parent34fb190ec0e2284ef44b34ead88bc192b1212286 (diff)
downloadlinux-b0aa75f0b1b2e6bc77128fab36c8ed87e84917cc.tar.xz
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>
Diffstat (limited to 'net/wireless/util.c')
-rw-r--r--net/wireless/util.c109
1 files changed, 109 insertions, 0 deletions
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 4293f980e9c4..ef14d80ca03e 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -5,17 +5,20 @@
* Copyright 2007-2009 Johannes Berg <johannes@sipsolutions.net>
* Copyright 2013-2014 Intel Mobile Communications GmbH
* Copyright 2017 Intel Deutschland GmbH
+ * Copyright (C) 2018 Intel Corporation
*/
#include <linux/export.h>
#include <linux/bitops.h>
#include <linux/etherdevice.h>
#include <linux/slab.h>
+#include <linux/ieee80211.h>
#include <net/cfg80211.h>
#include <net/ip.h>
#include <net/dsfield.h>
#include <linux/if_vlan.h>
#include <linux/mpls.h>
#include <linux/gcd.h>
+#include <linux/bitfield.h>
#include "core.h"
#include "rdev-ops.h"
@@ -1938,3 +1941,109 @@ void cfg80211_send_layer2_update(struct net_device *dev, const u8 *addr)
netif_rx_ni(skb);
}
EXPORT_SYMBOL(cfg80211_send_layer2_update);
+
+int ieee80211_get_vht_max_nss(struct ieee80211_vht_cap *cap,
+ enum ieee80211_vht_chanwidth bw,
+ int mcs, bool ext_nss_bw_capable)
+{
+ u16 map = le16_to_cpu(cap->supp_mcs.rx_mcs_map);
+ int max_vht_nss = 0;
+ int ext_nss_bw;
+ int supp_width;
+ int i, mcs_encoding;
+
+ if (map == 0xffff)
+ return 0;
+
+ if (WARN_ON(mcs > 9))
+ return 0;
+ if (mcs <= 7)
+ mcs_encoding = 0;
+ else if (mcs == 8)
+ mcs_encoding = 1;
+ else
+ mcs_encoding = 2;
+
+ /* find max_vht_nss for the given MCS */
+ for (i = 7; i >= 0; i--) {
+ int supp = (map >> (2 * i)) & 3;
+
+ if (supp == 3)
+ continue;
+
+ if (supp >= mcs_encoding) {
+ max_vht_nss = i;
+ break;
+ }
+ }
+
+ if (!(cap->supp_mcs.tx_mcs_map &
+ cpu_to_le16(IEEE80211_VHT_EXT_NSS_BW_CAPABLE)))
+ return max_vht_nss;
+
+ ext_nss_bw = le32_get_bits(cap->vht_cap_info,
+ IEEE80211_VHT_CAP_EXT_NSS_BW_MASK);
+ supp_width = le32_get_bits(cap->vht_cap_info,
+ IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_MASK);
+
+ /* if not capable, treat ext_nss_bw as 0 */
+ if (!ext_nss_bw_capable)
+ ext_nss_bw = 0;
+
+ /* This is invalid */
+ if (supp_width == 3)
+ return 0;
+
+ /* This is an invalid combination so pretend nothing is supported */
+ if (supp_width == 2 && (ext_nss_bw == 1 || ext_nss_bw == 2))
+ return 0;
+
+ /*
+ * Cover all the special cases according to IEEE 802.11-2016
+ * Table 9-250. All other cases are either factor of 1 or not
+ * valid/supported.
+ */
+ switch (bw) {
+ case IEEE80211_VHT_CHANWIDTH_USE_HT:
+ case IEEE80211_VHT_CHANWIDTH_80MHZ:
+ if ((supp_width == 1 || supp_width == 2) &&
+ ext_nss_bw == 3)
+ return 2 * max_vht_nss;
+ break;
+ case IEEE80211_VHT_CHANWIDTH_160MHZ:
+ if (supp_width == 0 &&
+ (ext_nss_bw == 1 || ext_nss_bw == 2))
+ return DIV_ROUND_UP(max_vht_nss, 2);
+ if (supp_width == 0 &&
+ ext_nss_bw == 3)
+ return DIV_ROUND_UP(3 * max_vht_nss, 4);
+ if (supp_width == 1 &&
+ ext_nss_bw == 3)
+ return 2 * max_vht_nss;
+ break;
+ case IEEE80211_VHT_CHANWIDTH_80P80MHZ:
+ if (supp_width == 0 &&
+ (ext_nss_bw == 1 || ext_nss_bw == 2))
+ return 0; /* not possible */
+ if (supp_width == 0 &&
+ ext_nss_bw == 2)
+ return DIV_ROUND_UP(max_vht_nss, 2);
+ if (supp_width == 0 &&
+ ext_nss_bw == 3)
+ return DIV_ROUND_UP(3 * max_vht_nss, 4);
+ if (supp_width == 1 &&
+ ext_nss_bw == 0)
+ return 0; /* not possible */
+ if (supp_width == 1 &&
+ ext_nss_bw == 1)
+ return DIV_ROUND_UP(max_vht_nss, 2);
+ if (supp_width == 1 &&
+ ext_nss_bw == 2)
+ return DIV_ROUND_UP(3 * max_vht_nss, 4);
+ break;
+ }
+
+ /* not covered or invalid combination received */
+ return max_vht_nss;
+}
+EXPORT_SYMBOL(ieee80211_get_vht_max_nss);