ath10k: add spectral scan feature

Adds the spectral scan feature for ath10k. 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:

ip link set dev wlan0 up
echo background > /sys/kernel/debug/ieee80211/phy0/ath10k/spectral_scan_ctl
echo trigger > /sys/kernel/debug/ieee80211/phy0/ath10k/spectral_scan_ctl
iw dev wlan0 scan
echo disable > /sys/kernel/debug/ieee80211/phy0/ath10k/spectral_scan_ctl
cat /sys/kernel/debug/ieee80211/phy0/ath10k/spectral_scan0 > samples

This feature is still experimental. Based on the original RFC patch of
Sven Eckelmann.

Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
diff --git a/drivers/net/wireless/ath/spectral_common.h b/drivers/net/wireless/ath/spectral_common.h
index b9ab722..0d742ac 100644
--- a/drivers/net/wireless/ath/spectral_common.h
+++ b/drivers/net/wireless/ath/spectral_common.h
@@ -20,6 +20,11 @@
 #define SPECTRAL_HT20_NUM_BINS		56
 #define SPECTRAL_HT20_40_NUM_BINS		128
 
+/* TODO: could possibly be 512, but no samples this large
+ * could be acquired so far.
+ */
+#define SPECTRAL_ATH10K_MAX_NUM_BINS		256
+
 /* FFT sample format given to userspace via debugfs.
  *
  * Please keep the type/length at the front position and change
@@ -31,6 +36,7 @@
 enum ath_fft_sample_type {
 	ATH_FFT_SAMPLE_HT20 = 1,
 	ATH_FFT_SAMPLE_HT20_40,
+	ATH_FFT_SAMPLE_ATH10K,
 };
 
 struct fft_sample_tlv {
@@ -85,4 +91,23 @@
 	u8 data[SPECTRAL_HT20_40_NUM_BINS];
 } __packed;
 
+struct fft_sample_ath10k {
+	struct fft_sample_tlv tlv;
+	u8 chan_width_mhz;
+	__be16 freq1;
+	__be16 freq2;
+	__be16 noise;
+	__be16 max_magnitude;
+	__be16 total_gain_db;
+	__be16 base_pwr_db;
+	__be64 tsf;
+	s8 max_index;
+	u8 rssi;
+	u8 relpwr_db;
+	u8 avgpwr_db;
+	u8 max_exp;
+
+	u8 data[0];
+} __packed;
+
 #endif /* SPECTRAL_COMMON_H */