mac80211: add support for indicating missing tx A-MPDU length

Signed-off-by: Felix Fietkau <nbd@nbd.name>

diff --git a/package/kernel/mac80211/patches/subsys/383-mac80211-minstrel_ht-add-flag-to-indicate-missing-in.patch b/package/kernel/mac80211/patches/subsys/383-mac80211-minstrel_ht-add-flag-to-indicate-missing-in.patch
new file mode 100644 (file)
index 0000000..2c706b1
--- /dev/null
+++ b/package/kernel/mac80211/patches/subsys/383-mac80211-minstrel_ht-add-flag-to-indicate-missing-in.patch
@@ -0,0 +1,121 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Wed, 16 Jan 2019 21:47:54 +0100
+Subject: [PATCH] mac80211: minstrel_ht: add flag to indicate
+ missing/inaccurate tx A-MPDU length
+
+Some hardware (e.g. MediaTek MT7603) cannot report A-MPDU length in tx status
+information. Add support for a flag to indicate that, to allow minstrel_ht
+to use a fixed value in its internal calculation (which gives better results
+than just defaulting to 1).
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/include/net/mac80211.h
++++ b/include/net/mac80211.h
+@@ -2132,6 +2132,9 @@ struct ieee80211_txq {
+  * @IEEE80211_HW_NEEDS_ALIGNED4_SKBS: Driver need aligned skbs to four-byte.
+  *    Padding will be added after ieee80211_hdr, before IV/LLC.
+  *
++ * @IEEE80211_HW_TX_STATUS_NO_AMPDU_LEN: Driver does not report accurate A-MPDU
++ *    length in tx status information
++ *
+  * @NUM_IEEE80211_HW_FLAGS: number of hardware flags, used for sizing arrays
+  */
+ enum ieee80211_hw_flags {
+@@ -2178,6 +2181,7 @@ enum ieee80211_hw_flags {
+       IEEE80211_HW_DEAUTH_NEED_MGD_TX_PREP,
+       IEEE80211_HW_DOESNT_SUPPORT_QOS_NDP,
+       IEEE80211_HW_NEEDS_ALIGNED4_SKBS,
++      IEEE80211_HW_TX_STATUS_NO_AMPDU_LEN,
+ 
+       /* keep last, obviously */
+       NUM_IEEE80211_HW_FLAGS
+--- a/net/mac80211/debugfs.c
++++ b/net/mac80211/debugfs.c
+@@ -215,6 +215,7 @@ static const char *hw_flag_names[] = {
+       FLAG(DEAUTH_NEED_MGD_TX_PREP),
+       FLAG(DOESNT_SUPPORT_QOS_NDP),
+       FLAG(NEEDS_ALIGNED4_SKBS),
++      FLAG(TX_STATUS_NO_AMPDU_LEN),
+ #undef FLAG
+ };
+ 
+--- a/net/mac80211/rc80211_minstrel_ht.c
++++ b/net/mac80211/rc80211_minstrel_ht.c
+@@ -294,6 +294,15 @@ minstrel_get_ratestats(struct minstrel_h
+       return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
+ }
+ 
++static unsigned int
++minstrel_ht_avg_ampdu_len(struct minstrel_ht_sta *mi)
++{
++      if (!mi->avg_ampdu_len)
++              return AVG_AMPDU_SIZE;
++
++      return MINSTREL_TRUNC(mi->avg_ampdu_len);
++}
++
+ /*
+  * Return current throughput based on the average A-MPDU length, taking into
+  * account the expected number of retransmissions and their expected length
+@@ -309,7 +318,7 @@ minstrel_ht_get_tp_avg(struct minstrel_h
+               return 0;
+ 
+       if (group != MINSTREL_CCK_GROUP)
+-              nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
++              nsecs = 1000 * mi->overhead / minstrel_ht_avg_ampdu_len(mi);
+ 
+       nsecs += minstrel_mcs_groups[group].duration[rate] <<
+                minstrel_mcs_groups[group].shift;
+@@ -503,8 +512,12 @@ minstrel_ht_update_stats(struct minstrel
+       u16 tmp_cck_tp_rate[MAX_THR_RATES], index;
+ 
+       if (mi->ampdu_packets > 0) {
+-              mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
+-                      MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
++              if (!ieee80211_hw_check(mp->hw, TX_STATUS_NO_AMPDU_LEN))
++                      mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
++                              MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets),
++                                            EWMA_LEVEL);
++              else
++                      mi->avg_ampdu_len = 0;
+               mi->ampdu_len = 0;
+               mi->ampdu_packets = 0;
+       }
+@@ -709,7 +722,9 @@ minstrel_ht_tx_status(void *priv, struct
+       mi->ampdu_len += info->status.ampdu_len;
+ 
+       if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
+-              mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
++              int avg_ampdu_len = minstrel_ht_avg_ampdu_len(mi);
++
++              mi->sample_wait = 16 + 2 * avg_ampdu_len;
+               mi->sample_tries = 1;
+               mi->sample_count--;
+       }
+@@ -777,7 +792,7 @@ minstrel_calc_retransmit(struct minstrel
+       unsigned int cw = mp->cw_min;
+       unsigned int ctime = 0;
+       unsigned int t_slot = 9; /* FIXME */
+-      unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
++      unsigned int ampdu_len = minstrel_ht_avg_ampdu_len(mi);
+       unsigned int overhead = 0, overhead_rtscts = 0;
+ 
+       mrs = minstrel_get_ratestats(mi, index);
+--- a/net/mac80211/rc80211_minstrel_ht_debugfs.c
++++ b/net/mac80211/rc80211_minstrel_ht_debugfs.c
+@@ -163,9 +163,10 @@ minstrel_ht_stats_open(struct inode *ino
+                       "lookaround %d\n",
+                       max(0, (int) mi->total_packets - (int) mi->sample_packets),
+                       mi->sample_packets);
+-      p += sprintf(p, "Average # of aggregated frames per A-MPDU: %d.%d\n",
+-              MINSTREL_TRUNC(mi->avg_ampdu_len),
+-              MINSTREL_TRUNC(mi->avg_ampdu_len * 10) % 10);
++      if (mi->avg_ampdu_len)
++              p += sprintf(p, "Average # of aggregated frames per A-MPDU: %d.%d\n",
++                      MINSTREL_TRUNC(mi->avg_ampdu_len),
++                      MINSTREL_TRUNC(mi->avg_ampdu_len * 10) % 10);
+       ms->len = p - ms->buf;
+       WARN_ON(ms->len + sizeof(*ms) > 32768);
+