mac80211: separate Tx and Rx MCS when configuring HT

This patch follows the 11n spec in separation between Tx and Rx MCS
capabilities. Up until now, when configuring the HT possible set of Tx
MCS only Rx MCS were considered, assuming they are the same as the Tx MCS.
This patch fixed this by looking at low level driver Tx capabilities.

Signed-off-by: Ron Rindjunsky <ron.rindjunsky@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 61 insertions, 35 deletions

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 36016363d225..b0fddb7de549 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -35,8 +35,6 @@
 #include "debugfs.h"
 #include "debugfs_netdev.h"
 
-#define SUPP_MCS_SET_LEN 16
-
 /*
  * For seeing transmitted packets on monitor interfaces
  * we have a radiotap header too.
@@ -1068,56 +1066,84 @@ u32 ieee80211_handle_ht(struct ieee80211_local *local, int enable_ht,
         struct ieee80211_supported_band *sband;
         struct ieee80211_ht_info ht_conf;
         struct ieee80211_ht_bss_info ht_bss_conf;
-        int i;
         u32 changed = 0;
+        int i;
+        u8 max_tx_streams = IEEE80211_HT_CAP_MAX_STREAMS;
+        u8 tx_mcs_set_cap;
 
         sband = local->hw.wiphy->bands[conf->channel->band];
 
+        memset(&ht_conf, 0, sizeof(struct ieee80211_ht_info));
+        memset(&ht_bss_conf, 0, sizeof(struct ieee80211_ht_bss_info));
+
         /* HT is not supported */
         if (!sband->ht_info.ht_supported) {
                 conf->flags &= ~IEEE80211_CONF_SUPPORT_HT_MODE;
-                return 0;
+                goto out;
         }
 
-        memset(&ht_conf, 0, sizeof(struct ieee80211_ht_info));
-        memset(&ht_bss_conf, 0, sizeof(struct ieee80211_ht_bss_info));
-
-        if (enable_ht) {
-                if (!(conf->flags & IEEE80211_CONF_SUPPORT_HT_MODE))
+        /* disable HT */
+        if (!enable_ht) {
+                if (conf->flags & IEEE80211_CONF_SUPPORT_HT_MODE)
                         changed |= BSS_CHANGED_HT;
+                conf->flags &= ~IEEE80211_CONF_SUPPORT_HT_MODE;
+                conf->ht_conf.ht_supported = 0;
+                goto out;
+        }
 
-                conf->flags |= IEEE80211_CONF_SUPPORT_HT_MODE;
-                ht_conf.ht_supported = 1;
 
-                ht_conf.cap = req_ht_cap->cap & sband->ht_info.cap;
-                ht_conf.cap &= ~(IEEE80211_HT_CAP_MIMO_PS);
-                ht_conf.cap |= sband->ht_info.cap & IEEE80211_HT_CAP_MIMO_PS;
+        if (!(conf->flags & IEEE80211_CONF_SUPPORT_HT_MODE))
+                changed |= BSS_CHANGED_HT;
 
-                for (i = 0; i < SUPP_MCS_SET_LEN; i++)
-                        ht_conf.supp_mcs_set[i] =
-                                        sband->ht_info.supp_mcs_set[i] &
-                                        req_ht_cap->supp_mcs_set[i];
+        conf->flags |= IEEE80211_CONF_SUPPORT_HT_MODE;
+        ht_conf.ht_supported = 1;
 
-                ht_bss_conf.primary_channel = req_bss_cap->primary_channel;
-                ht_bss_conf.bss_cap = req_bss_cap->bss_cap;
-                ht_bss_conf.bss_op_mode = req_bss_cap->bss_op_mode;
+        ht_conf.cap = req_ht_cap->cap & sband->ht_info.cap;
+        ht_conf.cap &= ~(IEEE80211_HT_CAP_MIMO_PS);
+        ht_conf.cap |= sband->ht_info.cap & IEEE80211_HT_CAP_MIMO_PS;
+        ht_bss_conf.primary_channel = req_bss_cap->primary_channel;
+        ht_bss_conf.bss_cap = req_bss_cap->bss_cap;
+        ht_bss_conf.bss_op_mode = req_bss_cap->bss_op_mode;
 
-                ht_conf.ampdu_factor = req_ht_cap->ampdu_factor;
-                ht_conf.ampdu_density = req_ht_cap->ampdu_density;
+        ht_conf.ampdu_factor = req_ht_cap->ampdu_factor;
+        ht_conf.ampdu_density = req_ht_cap->ampdu_density;
 
-                /* if bss configuration changed store the new one */
-                if (memcmp(&conf->ht_conf, &ht_conf, sizeof(ht_conf)) ||
-                    memcmp(&conf->ht_bss_conf, &ht_bss_conf, sizeof(ht_bss_conf))) {
-                        changed |= BSS_CHANGED_HT;
-                        memcpy(&conf->ht_conf, &ht_conf, sizeof(ht_conf));
-                        memcpy(&conf->ht_bss_conf, &ht_bss_conf, sizeof(ht_bss_conf));
-                }
-        } else {
-                if (conf->flags & IEEE80211_CONF_SUPPORT_HT_MODE)
-                        changed |= BSS_CHANGED_HT;
-                conf->flags &= ~IEEE80211_CONF_SUPPORT_HT_MODE;
-        }
+        /* Bits 96-100 */
+        tx_mcs_set_cap = sband->ht_info.supp_mcs_set[12];
 
+        /* configure suppoerted Tx MCS according to requested MCS
+         * (based in most cases on Rx capabilities of peer) and self
+         * Tx MCS capabilities (as defined by low level driver HW
+         * Tx capabilities) */
+        if (!(tx_mcs_set_cap & IEEE80211_HT_CAP_MCS_TX_DEFINED))
+                goto check_changed;
+
+        /* Counting from 0 therfore + 1 */
+        if (tx_mcs_set_cap & IEEE80211_HT_CAP_MCS_TX_RX_DIFF)
+                max_tx_streams = ((tx_mcs_set_cap &
+                                IEEE80211_HT_CAP_MCS_TX_STREAMS) >> 2) + 1;
+
+        for (i = 0; i < max_tx_streams; i++)
+                ht_conf.supp_mcs_set[i] =
+                        sband->ht_info.supp_mcs_set[i] &
+                                        req_ht_cap->supp_mcs_set[i];
+
+        if (tx_mcs_set_cap & IEEE80211_HT_CAP_MCS_TX_UEQM)
+                for (i = IEEE80211_SUPP_MCS_SET_UEQM;
+                     i < IEEE80211_SUPP_MCS_SET_LEN; i++)
+                        ht_conf.supp_mcs_set[i] =
+                                sband->ht_info.supp_mcs_set[i] &
+                                        req_ht_cap->supp_mcs_set[i];
+
+check_changed:
+        /* if bss configuration changed store the new one */
+        if (memcmp(&conf->ht_conf, &ht_conf, sizeof(ht_conf)) ||
+            memcmp(&conf->ht_bss_conf, &ht_bss_conf, sizeof(ht_bss_conf))) {
+                changed |= BSS_CHANGED_HT;
+                memcpy(&conf->ht_conf, &ht_conf, sizeof(ht_conf));
+                memcpy(&conf->ht_bss_conf, &ht_bss_conf, sizeof(ht_bss_conf));
+        }
+out:
         return changed;
 }