ath9k: Add support for Adaptive Power Management
This feature is to mitigate the problem of certain 3
stream chips that exceed the PCIe power requirements.An EEPROM flag
controls which chips have APM enabled which is basically read from
miscellaneous configuration element of the EEPROM header.
This workaround will reduce power consumption by using 2 Tx chains for
Single and Double stream rates (5 GHz only).All self generated frames
(regardless of rate) are sent on 2 chains when this feature is
enabled(Chip Limitation).
Cc: Paul Shaw <paul.shaw@atheros.com>
Signed-off-by: Mohammed Shafi Shajakhan <mshajakhan@atheros.com>
Tested-by: Mohammed Shafi Shajakhan <mshajakhan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index 177a7b1..821d367 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -1506,6 +1506,18 @@
return duration;
}
+u8 ath_txchainmask_reduction(struct ath_softc *sc, u8 chainmask, u32 rate)
+{
+ struct ath_hw *ah = sc->sc_ah;
+ struct ath9k_channel *curchan = ah->curchan;
+ if ((sc->sc_flags & SC_OP_ENABLE_APM) &&
+ (curchan->channelFlags & CHANNEL_5GHZ) &&
+ (chainmask == 0x7) && (rate < 0x90))
+ return 0x3;
+ else
+ return chainmask;
+}
+
static void ath_buf_set_rate(struct ath_softc *sc, struct ath_buf *bf, int len)
{
struct ath_common *common = ath9k_hw_common(sc->sc_ah);
@@ -1546,7 +1558,6 @@
rix = rates[i].idx;
series[i].Tries = rates[i].count;
- series[i].ChSel = common->tx_chainmask;
if ((sc->config.ath_aggr_prot && bf_isaggr(bf)) ||
(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS)) {
@@ -1569,6 +1580,8 @@
if (rates[i].flags & IEEE80211_TX_RC_MCS) {
/* MCS rates */
series[i].Rate = rix | 0x80;
+ series[i].ChSel = ath_txchainmask_reduction(sc,
+ common->tx_chainmask, series[i].Rate);
series[i].PktDuration = ath_pkt_duration(sc, rix, len,
is_40, is_sgi, is_sp);
if (rix < 8 && (tx_info->flags & IEEE80211_TX_CTL_STBC))
@@ -1576,7 +1589,7 @@
continue;
}
- /* legcay rates */
+ /* legacy rates */
if ((tx_info->band == IEEE80211_BAND_2GHZ) &&
!(rate->flags & IEEE80211_RATE_ERP_G))
phy = WLAN_RC_PHY_CCK;
@@ -1592,6 +1605,12 @@
is_sp = false;
}
+ if (bf->bf_state.bfs_paprd)
+ series[i].ChSel = common->tx_chainmask;
+ else
+ series[i].ChSel = ath_txchainmask_reduction(sc,
+ common->tx_chainmask, series[i].Rate);
+
series[i].PktDuration = ath9k_hw_computetxtime(sc->sc_ah,
phy, rate->bitrate * 100, len, rix, is_sp);
}