mac80211/drivers: rewrite the rate control API

So after the previous changes we were still unhappy with how
convoluted the API is and decided to make things simpler for
everybody. This completely changes the rate control API, now
taking into account 802.11n with MCS rates and more control,
most drivers don't support that though.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 59 insertions, 6 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-3945.c b/drivers/net/wireless/iwlwifi/iwl-3945.c
index 8a00245be51e..7afafb629706 100644
--- a/drivers/net/wireless/iwlwifi/iwl-3945.c
+++ b/drivers/net/wireless/iwlwifi/iwl-3945.c
@@ -261,6 +261,35 @@ static inline const char *iwl3945_get_tx_fail_reason(u32 status)
 }
 #endif
 
+/*
+ * get ieee prev rate from rate scale table.
+ * for A and B mode we need to overright prev
+ * value
+ */
+int iwl3945_rs_next_rate(struct iwl3945_priv *priv, int rate)
+{
+	int next_rate = iwl3945_get_prev_ieee_rate(rate);
+
+	switch (priv->band) {
+	case IEEE80211_BAND_5GHZ:
+		if (rate == IWL_RATE_12M_INDEX)
+			next_rate = IWL_RATE_9M_INDEX;
+		else if (rate == IWL_RATE_6M_INDEX)
+			next_rate = IWL_RATE_6M_INDEX;
+		break;
+/* XXX cannot be invoked in current mac80211 so not a regression
+	case MODE_IEEE80211B:
+		if (rate == IWL_RATE_11M_INDEX_TABLE)
+			next_rate = IWL_RATE_5M_INDEX_TABLE;
+		break;
+ */
+	default:
+		break;
+	}
+
+	return next_rate;
+}
+
 
 /**
  * iwl3945_tx_queue_reclaim - Reclaim Tx queue entries already Tx'd
@@ -308,6 +337,7 @@ static void iwl3945_rx_reply_tx(struct iwl3945_priv *priv,
 	struct iwl3945_tx_resp *tx_resp = (void *)&pkt->u.raw[0];
 	u32  status = le32_to_cpu(tx_resp->status);
 	int rate_idx;
+	int fail, i;
 
 	if ((index >= txq->q.n_bd) || (iwl3945_x2_queue_used(&txq->q, index) == 0)) {
 		IWL_ERROR("Read index for DMA queue txq_id (%d) index %d "
@@ -318,9 +348,36 @@ static void iwl3945_rx_reply_tx(struct iwl3945_priv *priv,
 	}
 
 	info = IEEE80211_SKB_CB(txq->txb[txq->q.read_ptr].skb[0]);
-	memset(&info->status, 0, sizeof(info->status));
+	ieee80211_tx_info_clear_status(info);
+
+	/* Fill the MRR chain with some info about on-chip retransmissions */
+	rate_idx = iwl3945_hwrate_to_plcp_idx(tx_resp->rate);
+	if (info->band == IEEE80211_BAND_5GHZ)
+		rate_idx -= IWL_FIRST_OFDM_RATE;
+
+	fail = tx_resp->failure_frame;
+	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
+		int next = iwl3945_rs_next_rate(priv, rate_idx);
+
+		info->status.rates[i].idx = rate_idx;
+
+		/*
+		 * Put remaining into the last count as best approximation
+		 * of saying exactly what the hardware would have done...
+		 */
+		if ((rate_idx == next) || (i == IEEE80211_TX_MAX_RATES - 1)) {
+			info->status.rates[i].count = fail;
+			break;
+		}
+
+		info->status.rates[i].count = priv->retry_rate;
+		fail -= priv->retry_rate;
+		rate_idx = next;
+		if (fail <= 0)
+			break;
+	}
+	info->status.rates[i].count++; /* add final attempt */
 
-	info->status.retry_count = tx_resp->failure_frame;
 	/* tx_status->rts_retry_count = tx_resp->failure_rts; */
 	info->flags |= ((status & TX_STATUS_MSK) == TX_STATUS_SUCCESS) ?
 				IEEE80211_TX_STAT_ACK : 0;
@@ -329,10 +386,6 @@ static void iwl3945_rx_reply_tx(struct iwl3945_priv *priv,
 			txq_id, iwl3945_get_tx_fail_reason(status), status,
 			tx_resp->rate, tx_resp->failure_frame);
 
-	rate_idx = iwl3945_hwrate_to_plcp_idx(tx_resp->rate);
-	if (info->band == IEEE80211_BAND_5GHZ)
-		rate_idx -= IWL_FIRST_OFDM_RATE;
-	info->tx_rate_idx = rate_idx;
 	IWL_DEBUG_TX_REPLY("Tx queue reclaim %d\n", index);
 	iwl3945_tx_queue_reclaim(priv, txq_id, index);