diff options
| -rw-r--r-- | drivers/net/wireless/iwlwifi/iwl-agn-lib.c | 51 |
1 files changed, 45 insertions, 6 deletions
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-lib.c b/drivers/net/wireless/iwlwifi/iwl-agn-lib.c index d339881..3577c1e 100644 --- a/drivers/net/wireless/iwlwifi/iwl-agn-lib.c +++ b/drivers/net/wireless/iwlwifi/iwl-agn-lib.c @@ -93,6 +93,12 @@ static int iwlagn_tx_status_reply_tx(struct iwl_priv *priv, } else { /* Two or more frames were attempted; expect block-ack */ u64 bitmap = 0; + + /* + * Start is the lowest frame sent. It may not be the first + * frame in the batch; we figure this out dynamically during + * the following loop. + */ int start = agg->start_idx; /* Construct bit-map of pending frames within Tx window */ @@ -131,25 +137,58 @@ static int iwlagn_tx_status_reply_tx(struct iwl_priv *priv, IWL_DEBUG_TX_REPLY(priv, "AGG Frame i=%d idx %d seq=%d\n", i, idx, SEQ_TO_SN(sc)); + /* + * sh -> how many frames ahead of the starting frame is + * the current one? + * + * Note that all frames sent in the batch must be in a + * 64-frame window, so this number should be in [0,63]. + * If outside of this window, then we've found a new + * "first" frame in the batch and need to change start. + */ sh = idx - start; - if (sh > 64) { - sh = (start - idx) + 0xff; + + /* + * If >= 64, out of window. start must be at the front + * of the circular buffer, idx must be near the end of + * the buffer, and idx is the new "first" frame. Shift + * the indices around. + */ + if (sh >= 64) { + /* Shift bitmap by start - idx, wrapped */ + sh = 0x100 - idx + start; bitmap = bitmap << sh; + /* Now idx is the new start so sh = 0 */ sh = 0; start = idx; - } else if (sh < -64) - sh = 0xff - (start - idx); - else if (sh < 0) { + /* + * If <= -64 then wraps the 256-pkt circular buffer + * (e.g., start = 255 and idx = 0, sh should be 1) + */ + } else if (sh <= -64) { + sh = 0x100 - start + idx; + /* + * If < 0 but > -64, out of window. idx is before start + * but not wrapped. Shift the indices around. + */ + } else if (sh < 0) { + /* Shift by how far start is ahead of idx */ sh = start - idx; - start = idx; bitmap = bitmap << sh; + /* Now idx is the new start so sh = 0 */ + start = idx; sh = 0; } + /* Sequence number start + sh was sent in this batch */ bitmap |= 1ULL << sh; IWL_DEBUG_TX_REPLY(priv, "start=%d bitmap=0x%llx\n", start, (unsigned long long)bitmap); } + /* + * Store the bitmap and possibly the new start, if we wrapped + * the buffer above + */ agg->bitmap = bitmap; agg->start_idx = start; IWL_DEBUG_TX_REPLY(priv, "Frames %d start_idx=%d bitmap=0x%llx\n", |
