iwlwifi: move chain settings to agn

The core module doesn't need to carry around
the code for chain settings that is used for
HT drivers (agn) only.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

1 files changed, 140 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-lib.c b/drivers/net/wireless/iwlwifi/iwl-agn-lib.c
index 3fa2c5c3706a..0b45bced9c0c 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-lib.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-lib.c
@@ -2065,3 +2065,143 @@ void iwlagn_bt_cancel_deferred_work(struct iwl_priv *priv)
 {
 	cancel_work_sync(&priv->bt_traffic_change_work);
 }
+
+static bool is_single_rx_stream(struct iwl_priv *priv)
+{
+	return priv->current_ht_config.smps == IEEE80211_SMPS_STATIC ||
+	       priv->current_ht_config.single_chain_sufficient;
+}
+
+#define IWL_NUM_RX_CHAINS_MULTIPLE	3
+#define IWL_NUM_RX_CHAINS_SINGLE	2
+#define IWL_NUM_IDLE_CHAINS_DUAL	2
+#define IWL_NUM_IDLE_CHAINS_SINGLE	1
+
+/*
+ * Determine how many receiver/antenna chains to use.
+ *
+ * More provides better reception via diversity.  Fewer saves power
+ * at the expense of throughput, but only when not in powersave to
+ * start with.
+ *
+ * MIMO (dual stream) requires at least 2, but works better with 3.
+ * This does not determine *which* chains to use, just how many.
+ */
+static int iwl_get_active_rx_chain_count(struct iwl_priv *priv)
+{
+	if (priv->cfg->bt_params &&
+	    priv->cfg->bt_params->advanced_bt_coexist &&
+	    (priv->bt_full_concurrent ||
+	     priv->bt_traffic_load >= IWL_BT_COEX_TRAFFIC_LOAD_HIGH)) {
+		/*
+		 * only use chain 'A' in bt high traffic load or
+		 * full concurrency mode
+		 */
+		return IWL_NUM_RX_CHAINS_SINGLE;
+	}
+	/* # of Rx chains to use when expecting MIMO. */
+	if (is_single_rx_stream(priv))
+		return IWL_NUM_RX_CHAINS_SINGLE;
+	else
+		return IWL_NUM_RX_CHAINS_MULTIPLE;
+}
+
+/*
+ * When we are in power saving mode, unless device support spatial
+ * multiplexing power save, use the active count for rx chain count.
+ */
+static int iwl_get_idle_rx_chain_count(struct iwl_priv *priv, int active_cnt)
+{
+	/* # Rx chains when idling, depending on SMPS mode */
+	switch (priv->current_ht_config.smps) {
+	case IEEE80211_SMPS_STATIC:
+	case IEEE80211_SMPS_DYNAMIC:
+		return IWL_NUM_IDLE_CHAINS_SINGLE;
+	case IEEE80211_SMPS_OFF:
+		return active_cnt;
+	default:
+		WARN(1, "invalid SMPS mode %d",
+		     priv->current_ht_config.smps);
+		return active_cnt;
+	}
+}
+
+/* up to 4 chains */
+static u8 iwl_count_chain_bitmap(u32 chain_bitmap)
+{
+	u8 res;
+	res = (chain_bitmap & BIT(0)) >> 0;
+	res += (chain_bitmap & BIT(1)) >> 1;
+	res += (chain_bitmap & BIT(2)) >> 2;
+	res += (chain_bitmap & BIT(3)) >> 3;
+	return res;
+}
+
+/**
+ * iwlagn_set_rxon_chain - Set up Rx chain usage in "staging" RXON image
+ *
+ * Selects how many and which Rx receivers/antennas/chains to use.
+ * This should not be used for scan command ... it puts data in wrong place.
+ */
+void iwlagn_set_rxon_chain(struct iwl_priv *priv, struct iwl_rxon_context *ctx)
+{
+	bool is_single = is_single_rx_stream(priv);
+	bool is_cam = !test_bit(STATUS_POWER_PMI, &priv->status);
+	u8 idle_rx_cnt, active_rx_cnt, valid_rx_cnt;
+	u32 active_chains;
+	u16 rx_chain;
+
+	/* Tell uCode which antennas are actually connected.
+	 * Before first association, we assume all antennas are connected.
+	 * Just after first association, iwl_chain_noise_calibration()
+	 *    checks which antennas actually *are* connected. */
+	if (priv->chain_noise_data.active_chains)
+		active_chains = priv->chain_noise_data.active_chains;
+	else
+		active_chains = priv->hw_params.valid_rx_ant;
+
+	if (priv->cfg->bt_params &&
+	    priv->cfg->bt_params->advanced_bt_coexist &&
+	    (priv->bt_full_concurrent ||
+	     priv->bt_traffic_load >= IWL_BT_COEX_TRAFFIC_LOAD_HIGH)) {
+		/*
+		 * only use chain 'A' in bt high traffic load or
+		 * full concurrency mode
+		 */
+		active_chains = first_antenna(active_chains);
+	}
+
+	rx_chain = active_chains << RXON_RX_CHAIN_VALID_POS;
+
+	/* How many receivers should we use? */
+	active_rx_cnt = iwl_get_active_rx_chain_count(priv);
+	idle_rx_cnt = iwl_get_idle_rx_chain_count(priv, active_rx_cnt);
+
+
+	/* correct rx chain count according hw settings
+	 * and chain noise calibration
+	 */
+	valid_rx_cnt = iwl_count_chain_bitmap(active_chains);
+	if (valid_rx_cnt < active_rx_cnt)
+		active_rx_cnt = valid_rx_cnt;
+
+	if (valid_rx_cnt < idle_rx_cnt)
+		idle_rx_cnt = valid_rx_cnt;
+
+	rx_chain |= active_rx_cnt << RXON_RX_CHAIN_MIMO_CNT_POS;
+	rx_chain |= idle_rx_cnt  << RXON_RX_CHAIN_CNT_POS;
+
+	ctx->staging.rx_chain = cpu_to_le16(rx_chain);
+
+	if (!is_single && (active_rx_cnt >= IWL_NUM_RX_CHAINS_SINGLE) && is_cam)
+		ctx->staging.rx_chain |= RXON_RX_CHAIN_MIMO_FORCE_MSK;
+	else
+		ctx->staging.rx_chain &= ~RXON_RX_CHAIN_MIMO_FORCE_MSK;
+
+	IWL_DEBUG_ASSOC(priv, "rx_chain=0x%X active=%d idle=%d\n",
+			ctx->staging.rx_chain,
+			active_rx_cnt, idle_rx_cnt);
+
+	WARN_ON(active_rx_cnt == 0 || idle_rx_cnt == 0 ||
+		active_rx_cnt < idle_rx_cnt);
+}