ath9k: add spectral scan feature

Adds the spectral scan feature for ath9k. AR92xx and AR93xx chips
are supported for now. The spectral scan is triggered by configuring
a mode through a debugfs control file. Samples can be gathered via
another relay debugfs file.

Essentially, to try it out:

echo chanscan > /sys/kernel/debug/ieee80211/phy0/ath9k/spectral_scan_ctl
iw dev wlan0 scan
cat /sys/kernel/debug/ieee80211/phy0/ath9k/spectral_scan0 > samples
echo disable > /sys/kernel/debug/ieee80211/phy0/ath9k/spectral_scan_ctl

This feature is still experimental.

The special "chanscan" mode is used to perform spectral scan while
mac80211 is scanning for channels. To allow this,
sw_scan_start/complete() ops have been added.

The patch contains code snippets and information from Zefir Kurtisi and
information provided by Adrian Chadd and Felix Fietkau.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 64 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath9k/ar9002_phy.c b/drivers/net/wireless/ath/ath9k/ar9002_phy.c
index 8b119811b2d..51b7c8130ae 100644
--- a/drivers/net/wireless/ath/ath9k/ar9002_phy.c
+++ b/drivers/net/wireless/ath/ath9k/ar9002_phy.c
@@ -555,6 +555,67 @@ static void ar9002_hw_antdiv_comb_conf_set(struct ath_hw *ah,
 	REG_WRITE(ah, AR_PHY_MULTICHAIN_GAIN_CTL, regval);
 }
 
+void ar9002_hw_spectral_scan_config(struct ath_hw *ah,
+				    struct ath_spec_scan *param)
+{
+	u8 count;
+
+	if (!param->enabled) {
+		REG_CLR_BIT(ah, AR_PHY_SPECTRAL_SCAN,
+			    AR_PHY_SPECTRAL_SCAN_ENABLE);
+		return;
+	}
+	REG_SET_BIT(ah, AR_PHY_RADAR_0, AR_PHY_RADAR_0_FFT_ENA);
+	REG_SET_BIT(ah, AR_PHY_SPECTRAL_SCAN, AR_PHY_SPECTRAL_SCAN_ENABLE);
+
+	if (param->short_repeat)
+		REG_SET_BIT(ah, AR_PHY_SPECTRAL_SCAN,
+			    AR_PHY_SPECTRAL_SCAN_SHORT_REPEAT);
+	else
+		REG_CLR_BIT(ah, AR_PHY_SPECTRAL_SCAN,
+			    AR_PHY_SPECTRAL_SCAN_SHORT_REPEAT);
+
+	/* on AR92xx, the highest bit of count will make the the chip send
+	 * spectral samples endlessly. Check if this really was intended,
+	 * and fix otherwise.
+	 */
+	count = param->count;
+	if (param->endless)
+		count = 0;
+	else if (count & 0x80)
+		count = 0x7f;
+
+	REG_RMW_FIELD(ah, AR_PHY_SPECTRAL_SCAN,
+		      AR_PHY_SPECTRAL_SCAN_COUNT, count);
+	REG_RMW_FIELD(ah, AR_PHY_SPECTRAL_SCAN,
+		      AR_PHY_SPECTRAL_SCAN_PERIOD, param->period);
+	REG_RMW_FIELD(ah, AR_PHY_SPECTRAL_SCAN,
+		      AR_PHY_SPECTRAL_SCAN_FFT_PERIOD, param->fft_period);
+
+	return;
+}
+
+static void ar9002_hw_spectral_scan_trigger(struct ath_hw *ah)
+{
+	REG_SET_BIT(ah, AR_PHY_SPECTRAL_SCAN, AR_PHY_SPECTRAL_SCAN_ENABLE);
+	/* Activate spectral scan */
+	REG_SET_BIT(ah, AR_PHY_SPECTRAL_SCAN,
+		    AR_PHY_SPECTRAL_SCAN_ACTIVE);
+}
+
+static void ar9002_hw_spectral_scan_wait(struct ath_hw *ah)
+{
+	struct ath_common *common = ath9k_hw_common(ah);
+
+	/* Poll for spectral scan complete */
+	if (!ath9k_hw_wait(ah, AR_PHY_SPECTRAL_SCAN,
+			   AR_PHY_SPECTRAL_SCAN_ACTIVE,
+			   0, AH_WAIT_TIMEOUT)) {
+		ath_err(common, "spectral scan wait failed\n");
+		return;
+	}
+}
+
 void ar9002_hw_attach_phy_ops(struct ath_hw *ah)
 {
 	struct ath_hw_private_ops *priv_ops = ath9k_hw_private_ops(ah);
@@ -569,6 +630,9 @@ void ar9002_hw_attach_phy_ops(struct ath_hw *ah)
 
 	ops->antdiv_comb_conf_get = ar9002_hw_antdiv_comb_conf_get;
 	ops->antdiv_comb_conf_set = ar9002_hw_antdiv_comb_conf_set;
+	ops->spectral_scan_config = ar9002_hw_spectral_scan_config;
+	ops->spectral_scan_trigger = ar9002_hw_spectral_scan_trigger;
+	ops->spectral_scan_wait = ar9002_hw_spectral_scan_wait;
 
 	ar9002_hw_set_nf_limits(ah);
 }