mac80211: add multi-rate retry support

This patch adjusts the rate control API to allow multi-rate retry
if supported by the driver. The ieee80211_hw struct specifies how
many alternate rate selections the driver supports.

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

1 files changed, 25 insertions, 4 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index feb3be81dfa6..5617a1613c91 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -292,6 +292,20 @@ enum mac80211_tx_control_flags {
 #define IEEE80211_TX_INFO_DRIVER_DATA_PTRS \
         (IEEE80211_TX_INFO_DRIVER_DATA_SIZE / sizeof(void *))
 
+/* maximum number of alternate rate retry stages */
+#define IEEE80211_TX_MAX_ALTRATE        3
+
+/**
+ * struct ieee80211_tx_altrate - alternate rate selection/status
+ *
+ * @rate_idx: rate index to attempt to send with
+ * @limit: number of retries before fallback
+ */
+struct ieee80211_tx_altrate {
+        s8 rate_idx;
+        u8 limit;
+};
+
 /**
  * struct ieee80211_tx_info - skb transmit information
  *
@@ -335,12 +349,14 @@ struct ieee80211_tx_info {
                         struct ieee80211_key_conf *hw_key;
                         struct ieee80211_sta *sta;
                         unsigned long jiffies;
-                        s8 rts_cts_rate_idx, alt_retry_rate_idx;
+                        s8 rts_cts_rate_idx;
                         u8 retry_limit;
+                        struct ieee80211_tx_altrate retries[IEEE80211_TX_MAX_ALTRATE];
                 } control;
                 struct {
                         u64 ampdu_ack_map;
                         int ack_signal;
+                        struct ieee80211_tx_altrate retries[IEEE80211_TX_MAX_ALTRATE + 1];
                         u8 retry_count;
                         bool excessive_retries;
                         u8 ampdu_ack_len;
@@ -828,6 +844,9 @@ enum ieee80211_hw_flags {
  *      within &struct ieee80211_vif.
  * @sta_data_size: size (in bytes) of the drv_priv data area
  *      within &struct ieee80211_sta.
+ *
+ * @max_altrates: maximum number of alternate rate retry stages
+ * @max_altrate_tries: maximum number of tries for each stage
  */
 struct ieee80211_hw {
         struct ieee80211_conf conf;
@@ -844,6 +863,8 @@ struct ieee80211_hw {
         u16 ampdu_queues;
         u16 max_listen_interval;
         s8 max_signal;
+        u8 max_altrates;
+        u8 max_altrate_tries;
 };
 
 struct ieee80211_hw *wiphy_to_hw(struct wiphy *wiphy);
@@ -900,11 +921,11 @@ ieee80211_get_rts_cts_rate(const struct ieee80211_hw *hw,
 
 static inline struct ieee80211_rate *
 ieee80211_get_alt_retry_rate(const struct ieee80211_hw *hw,
-                             const struct ieee80211_tx_info *c)
+                             const struct ieee80211_tx_info *c, int idx)
 {
-        if (c->control.alt_retry_rate_idx < 0)
+        if (c->control.retries[idx].rate_idx < 0)
                 return NULL;
-        return &hw->wiphy->bands[c->band]->bitrates[c->control.alt_retry_rate_idx];
+        return &hw->wiphy->bands[c->band]->bitrates[c->control.retries[idx].rate_idx];
 }
 
 /**