wifi: iwlwifi: mvm: add EHT A-MPDU size exponent support

Add support for reading the EHT MAC capabilities A-MPDU
size exponent field, as indicated by the draft spec.

Also clarify the existing code a bit and add comments
so it's clearer to understand what's going on here.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230620125813.c5e00045d90f.I7520787fca8f8430a564adedf975d069ad8c5417@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/sta.c b/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
index 3c24b25..37a52ff 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
@@ -60,22 +60,27 @@ u32 iwl_mvm_get_sta_ampdu_dens(struct ieee80211_link_sta *link_sta,
        if (WARN_ON(!link_sta))
                return 0;
 
-       if (link_sta->ht_cap.ht_supported)
+       /* Note that we always use only legacy & highest supported PPDUs, so
+        * of Draft P802.11be D.30 Table 10-12a--Fields used for calculating
+        * the maximum A-MPDU size of various PPDU types in different bands,
+        * we only need to worry about the highest supported PPDU type here.
+        */
+
+       if (link_sta->ht_cap.ht_supported) {
+               agg_size = link_sta->ht_cap.ampdu_factor;
                mpdu_dens = link_sta->ht_cap.ampdu_density;
+       }
 
-       if (link_conf->chandef.chan->band ==
-           NL80211_BAND_6GHZ) {
+       if (link_conf->chandef.chan->band == NL80211_BAND_6GHZ) {
+               /* overwrite HT values on 6 GHz */
                mpdu_dens = le16_get_bits(link_sta->he_6ghz_capa.capa,
                                          IEEE80211_HE_6GHZ_CAP_MIN_MPDU_START);
                agg_size = le16_get_bits(link_sta->he_6ghz_capa.capa,
                                         IEEE80211_HE_6GHZ_CAP_MAX_AMPDU_LEN_EXP);
        } else if (link_sta->vht_cap.vht_supported) {
-               agg_size = link_sta->vht_cap.cap &
-                       IEEE80211_VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_MASK;
-               agg_size >>=
-                       IEEE80211_VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_SHIFT;
-       } else if (link_sta->ht_cap.ht_supported) {
-               agg_size = link_sta->ht_cap.ampdu_factor;
+               /* if VHT supported overwrite HT value */
+               agg_size = u32_get_bits(link_sta->vht_cap.cap,
+                                       IEEE80211_VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_MASK);
        }
 
        /* D6.0 10.12.2 A-MPDU length limit rules
@@ -91,6 +96,10 @@ u32 iwl_mvm_get_sta_ampdu_dens(struct ieee80211_link_sta *link_sta,
                        u8_get_bits(link_sta->he_cap.he_cap_elem.mac_cap_info[3],
                                    IEEE80211_HE_MAC_CAP3_MAX_AMPDU_LEN_EXP_MASK);
 
+       if (link_sta->eht_cap.has_eht)
+               agg_size += u8_get_bits(link_sta->eht_cap.eht_cap_elem.mac_cap_info[1],
+                                       IEEE80211_EHT_MAC_CAP1_MAX_AMPDU_LEN_MASK);
+
        /* Limit to max A-MPDU supported by FW */
        agg_size = min_t(u32, agg_size,
                         STA_FLG_MAX_AGG_SIZE_4M >> STA_FLG_MAX_AGG_SIZE_SHIFT);