ath9k_hw: clean up tx power handling

The code for handling various restrictions concerning regulatory limits,
antenna gain, etc. is very convoluted and duplicated across various
EEPROM parsing implementations, making it hard to review.

This patch partially cleans up the mess by unifying regulatory limit
handling in one function and simplifying handling of antenna gain.
It also removes unused transmit power scaling arrays from the EEPROM code,
which belonged to an unimplemented API that isn't supposed to be in
the driver anyway.

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

1 files changed, 43 insertions, 20 deletions

diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index 42ebe8fb053..949656d928d 100644
--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -433,7 +433,6 @@ static void ath9k_hw_init_defaults(struct ath_hw *ah)
 
 	regulatory->country_code = CTRY_DEFAULT;
 	regulatory->power_limit = MAX_RATE_POWER;
-	regulatory->tp_scale = ATH9K_TP_SCALE_MAX;
 
 	ah->hw_version.magic = AR5416_MAGIC;
 	ah->hw_version.subvendorid = 0;
@@ -1389,9 +1388,7 @@ static bool ath9k_hw_chip_reset(struct ath_hw *ah,
 static bool ath9k_hw_channel_change(struct ath_hw *ah,
 				    struct ath9k_channel *chan)
 {
-	struct ath_regulatory *regulatory = ath9k_hw_regulatory(ah);
 	struct ath_common *common = ath9k_hw_common(ah);
-	struct ieee80211_channel *channel = chan->chan;
 	u32 qnum;
 	int r;
 
@@ -1416,14 +1413,7 @@ static bool ath9k_hw_channel_change(struct ath_hw *ah,
 		return false;
 	}
 	ath9k_hw_set_clockrate(ah);
-
-	ah->eep_ops->set_txpower(ah, chan,
-			     ath9k_regd_get_ctl(regulatory, chan),
-			     channel->max_antenna_gain * 2,
-			     channel->max_power * 2,
-			     min((u32) MAX_RATE_POWER,
-			     (u32) regulatory->power_limit), false);
-
+	ath9k_hw_apply_txpower(ah, chan);
 	ath9k_hw_rfbus_done(ah);
 
 	if (IS_CHAN_OFDM(chan) || IS_CHAN_HT(chan))
@@ -2498,23 +2488,56 @@ bool ath9k_hw_disable(struct ath_hw *ah)
 }
 EXPORT_SYMBOL(ath9k_hw_disable);
 
+static int get_antenna_gain(struct ath_hw *ah, struct ath9k_channel *chan)
+{
+	enum eeprom_param gain_param;
+
+	if (IS_CHAN_2GHZ(chan))
+		gain_param = EEP_ANTENNA_GAIN_2G;
+	else
+		gain_param = EEP_ANTENNA_GAIN_5G;
+
+	return ah->eep_ops->get_eeprom(ah, gain_param);
+}
+
+void ath9k_hw_apply_txpower(struct ath_hw *ah, struct ath9k_channel *chan)
+{
+	struct ath_regulatory *reg = ath9k_hw_regulatory(ah);
+	struct ieee80211_channel *channel;
+	int chan_pwr, new_pwr, max_gain;
+	int ant_gain, ant_reduction = 0;
+
+	if (!chan)
+		return;
+
+	channel = chan->chan;
+	chan_pwr = min_t(int, channel->max_power * 2, MAX_RATE_POWER);
+	new_pwr = min_t(int, chan_pwr, reg->power_limit);
+	max_gain = chan_pwr - new_pwr + channel->max_antenna_gain * 2;
+
+	ant_gain = get_antenna_gain(ah, chan);
+	if (ant_gain > max_gain)
+		ant_reduction = ant_gain - max_gain;
+
+	ah->eep_ops->set_txpower(ah, chan,
+				 ath9k_regd_get_ctl(reg, chan),
+				 ant_reduction, new_pwr, false);
+}
+
 void ath9k_hw_set_txpowerlimit(struct ath_hw *ah, u32 limit, bool test)
 {
-	struct ath_regulatory *regulatory = ath9k_hw_regulatory(ah);
+	struct ath_regulatory *reg = ath9k_hw_regulatory(ah);
 	struct ath9k_channel *chan = ah->curchan;
 	struct ieee80211_channel *channel = chan->chan;
-	int reg_pwr = min_t(int, MAX_RATE_POWER, limit);
-	int chan_pwr = channel->max_power * 2;
 
+	reg->power_limit = min_t(int, limit, MAX_RATE_POWER);
 	if (test)
-		reg_pwr = chan_pwr = MAX_RATE_POWER;
+		channel->max_power = MAX_RATE_POWER / 2;
 
-	regulatory->power_limit = reg_pwr;
+	ath9k_hw_apply_txpower(ah, chan);
 
-	ah->eep_ops->set_txpower(ah, chan,
-				 ath9k_regd_get_ctl(regulatory, chan),
-				 channel->max_antenna_gain * 2,
-				 chan_pwr, reg_pwr, test);
+	if (test)
+		channel->max_power = DIV_ROUND_UP(reg->max_power_level, 2);
 }
 EXPORT_SYMBOL(ath9k_hw_set_txpowerlimit);