iwlwifi: cleanup and bugfix tx aggregation code

Since the driver split, there's no need for no_agg_framecnt_info since
all devices have this set to false. Secondly, the compressed block ack
handling code was broken. Fix this.

(1) A shift less than zero simply implies that the buffer wrapped, this
is expected. Remove the incorrect comment.

(2) The (agg->frame_count > (64-sh)) condition can happen if the last
frame is dropped. E.g., if I send 7 frames and the 6th is received but
the 7th is lost, the other side may only shift the window 6, not 7
frames since the last bit is a 0. This is perfectly fine behavior and
doesn't invalidate the feedback.

(3) Store the feedback from a Compressed BA in the first newly received
frame, rather than the start of the window. This way it will get
processed by the rate selection code. Feedback stored in a non-received
frame is likely to get overwritten by the retransmission.
    This is based on the approach taken by minstrel_ht.

Signed-off-by: Daniel Halperin <dhalperi@cs.washington.edu>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

2 files changed, 27 insertions, 58 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
index fb63a03a395e..cb8eacd5fdb5 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
@@ -1263,11 +1263,11 @@ static int iwlagn_tx_status_reply_compressed_ba(struct iwl_priv *priv,
                                  struct iwl_compressed_ba_resp *ba_resp)
 
 {
-        int i, sh, ack;
+        int sh;
         u16 seq_ctl = le16_to_cpu(ba_resp->seq_ctl);
         u16 scd_flow = le16_to_cpu(ba_resp->scd_flow);
-        int successes = 0;
         struct ieee80211_tx_info *info;
+        u64 bitmap, sent_bitmap;
 
         if (unlikely(!agg->wait_for_ba))  {
                 if (unlikely(ba_resp->bitmap))
@@ -1281,70 +1281,42 @@ static int iwlagn_tx_status_reply_compressed_ba(struct iwl_priv *priv,
 
         /* Calculate shift to align block-ack bits with our Tx window bits */
         sh = agg->start_idx - SEQ_TO_INDEX(seq_ctl >> 4);
-        if (sh < 0) /* tbw something is wrong with indices */
+        if (sh < 0)
                 sh += 0x100;
 
-        if (agg->frame_count > (64 - sh)) {
-                IWL_DEBUG_TX_REPLY(priv, "more frames than bitmap size");
-                return -1;
-        }
-        if (!priv->cfg->base_params->no_agg_framecnt_info && ba_resp->txed) {
+        /*
+         * Check for success or failure according to the
+         * transmitted bitmap and block-ack bitmap
+         */
+        bitmap = le64_to_cpu(ba_resp->bitmap) >> sh;
+        sent_bitmap = bitmap & agg->bitmap;
+
+        /* Sanity check values reported by uCode */
+        if (ba_resp->txed_2_done > ba_resp->txed) {
+                IWL_DEBUG_TX_REPLY(priv,
+                        "bogus sent(%d) and ack(%d) count\n",
+                        ba_resp->txed, ba_resp->txed_2_done);
                 /*
-                 * sent and ack information provided by uCode
-                 * use it instead of figure out ourself
+                 * set txed_2_done = txed,
+                 * so it won't impact rate scale
                  */
-                if (ba_resp->txed_2_done > ba_resp->txed) {
-                        IWL_DEBUG_TX_REPLY(priv,
-                                "bogus sent(%d) and ack(%d) count\n",
-                                ba_resp->txed, ba_resp->txed_2_done);
-                        /*
-                         * set txed_2_done = txed,
-                         * so it won't impact rate scale
-                         */
-                        ba_resp->txed = ba_resp->txed_2_done;
-                }
-                IWL_DEBUG_HT(priv, "agg frames sent:%d, acked:%d\n",
-                                ba_resp->txed, ba_resp->txed_2_done);
-        } else {
-                u64 bitmap, sent_bitmap;
-
-                /* don't use 64-bit values for now */
-                bitmap = le64_to_cpu(ba_resp->bitmap) >> sh;
-
-                /* check for success or failure according to the
-                 * transmitted bitmap and block-ack bitmap */
-                sent_bitmap = bitmap & agg->bitmap;
-
-                /* For each frame attempted in aggregation,
-                 * update driver's record of tx frame's status. */
-                i = 0;
-                while (sent_bitmap) {
-                        ack = sent_bitmap & 1ULL;
-                        successes += ack;
-                        IWL_DEBUG_TX_REPLY(priv, "%s ON i=%d idx=%d raw=%d\n",
-                                ack ? "ACK" : "NACK", i,
-                                (agg->start_idx + i) & 0xff,
-                                agg->start_idx + i);
-                        sent_bitmap >>= 1;
-                        ++i;
-                }
+                ba_resp->txed = ba_resp->txed_2_done;
+        }
+        IWL_DEBUG_HT(priv, "agg frames sent:%d, acked:%d\n",
+                        ba_resp->txed, ba_resp->txed_2_done);
 
-                IWL_DEBUG_TX_REPLY(priv, "Bitmap %llx\n",
-                                   (unsigned long long)bitmap);
+        /* Find the first ACKed frame to store the TX status */
+        while (sent_bitmap && !(sent_bitmap & 1)) {
+                agg->start_idx = (agg->start_idx + 1) & 0xff;
+                sent_bitmap >>= 1;
         }
 
         info = IEEE80211_SKB_CB(priv->txq[scd_flow].txb[agg->start_idx].skb);
         memset(&info->status, 0, sizeof(info->status));
         info->flags |= IEEE80211_TX_STAT_ACK;
         info->flags |= IEEE80211_TX_STAT_AMPDU;
-        if (!priv->cfg->base_params->no_agg_framecnt_info && ba_resp->txed) {
-                info->status.ampdu_ack_len = ba_resp->txed_2_done;
-                info->status.ampdu_len = ba_resp->txed;
-
-        } else {
-                info->status.ampdu_ack_len = successes;
-                info->status.ampdu_len = agg->frame_count;
-        }
+        info->status.ampdu_ack_len = ba_resp->txed_2_done;
+        info->status.ampdu_len = ba_resp->txed;
         iwlagn_hwrate_to_tx_control(priv, agg->rate_n_flags, info);
 
         return 0;
diff --git a/drivers/net/wireless/iwlwifi/iwl-core.h b/drivers/net/wireless/iwlwifi/iwl-core.h
index 1f4f6dd18009..3e680af7ff70 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.h
+++ b/drivers/net/wireless/iwlwifi/iwl-core.h
@@ -281,8 +281,6 @@ struct iwl_mod_params {
  * @chain_noise_calib_by_driver: driver has the capability to perform
  *      chain noise calibration operation
  * @shadow_reg_enable: HW shadhow register bit
- * @no_agg_framecnt_info: uCode do not provide aggregation frame count
- *      information
  */
 struct iwl_base_params {
         int eeprom_size;
@@ -312,7 +310,6 @@ struct iwl_base_params {
         const bool sensitivity_calib_by_driver;
         const bool chain_noise_calib_by_driver;
         const bool shadow_reg_enable;
-        const bool no_agg_framecnt_info;
 };
 /*
  * @advanced_bt_coexist: support advanced bt coexist