ath5k: Adaptive Noise Immunity (ANI) Implementation

This is an Adaptive Noise Imunity (ANI) implementation for ath5k. I have looked
at both ath9k and HAL sources (they are nearly the same), and even though i
have implemented some things differently, the basic algorithm is practically
the same, for now. I hope that this can serve as a clean start to improve the
algorithm later.

This also adds a possibility to manually control ANI settings, right now only
thru a debugfs file:
  * set lowest sensitivity (=highest noise immunity):
	echo sens-low > /sys/kernel/debug/ath5k/phy0/ani
  * set highest sensitivity (=lowest noise immunity):
	echo sens-high > /sys/kernel/debug/ath5k/phy0/ani
  * automatically control immunity (default):
	echo ani-on > /sys/kernel/debug/ath5k/phy0/ani
  * to see the parameters in use and watch them change:
	cat /sys/kernel/debug/ath5k/phy0/ani

Manually setting sensitivity will turn the automatic control off. You can also
control each of the five immunity parameters (noise immunity, spur immunity,
firstep, ofdm weak signal detection, cck weak signal detection) manually thru
the debugfs file.

This is tested on AR5414 and nearly doubles the thruput in a noisy 2GHz band.

Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 104 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath5k/ani.h b/drivers/net/wireless/ath/ath5k/ani.h
new file mode 100644
index 000000000000..55cf26d8522c
--- /dev/null
+++ b/drivers/net/wireless/ath/ath5k/ani.h
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2010 Bruno Randolf <br1@einfach.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+#ifndef ANI_H
+#define ANI_H
+
+/* these thresholds are relative to the ATH5K_ANI_LISTEN_PERIOD */
+#define ATH5K_ANI_LISTEN_PERIOD		100
+#define ATH5K_ANI_OFDM_TRIG_HIGH	500
+#define ATH5K_ANI_OFDM_TRIG_LOW		200
+#define ATH5K_ANI_CCK_TRIG_HIGH		200
+#define ATH5K_ANI_CCK_TRIG_LOW		100
+
+/* average beacon RSSI thresholds */
+#define ATH5K_ANI_RSSI_THR_HIGH		40
+#define ATH5K_ANI_RSSI_THR_LOW		7
+
+/* maximum availabe levels */
+#define ATH5K_ANI_MAX_FIRSTEP_LVL	2
+#define ATH5K_ANI_MAX_NOISE_IMM_LVL	1
+
+
+/**
+ * enum ath5k_ani_mode - mode for ANI / noise sensitivity
+ *
+ * @ATH5K_ANI_MODE_OFF: Turn ANI off. This can be useful to just stop the ANI
+ *	algorithm after it has been on auto mode.
+ * ATH5K_ANI_MODE_MANUAL_LOW: Manually set all immunity parameters to low,
+ *	maximizing sensitivity. ANI will not run.
+ * ATH5K_ANI_MODE_MANUAL_HIGH: Manually set all immunity parameters to high,
+ *	minimizing sensitivity. ANI will not run.
+ * ATH5K_ANI_MODE_AUTO: Automatically control immunity parameters based on the
+ *	amount of OFDM and CCK frame errors (default).
+ */
+enum ath5k_ani_mode {
+	ATH5K_ANI_MODE_OFF		= 0,
+	ATH5K_ANI_MODE_MANUAL_LOW	= 1,
+	ATH5K_ANI_MODE_MANUAL_HIGH	= 2,
+	ATH5K_ANI_MODE_AUTO		= 3
+};
+
+
+/**
+ * struct ath5k_ani_state - ANI state and associated counters
+ *
+ * @max_spur_level: the maximum spur level is chip dependent
+ */
+struct ath5k_ani_state {
+	enum ath5k_ani_mode	ani_mode;
+
+	/* state */
+	int			noise_imm_level;
+	int			spur_level;
+	int			firstep_level;
+	bool			ofdm_weak_sig;
+	bool			cck_weak_sig;
+
+	int			max_spur_level;
+
+	/* used by the algorithm */
+	unsigned int		listen_time;
+	unsigned int		ofdm_errors;
+	unsigned int		cck_errors;
+
+	/* debug/statistics only: numbers from last ANI calibration */
+	unsigned int		pfc_tx;
+	unsigned int		pfc_rx;
+	unsigned int		pfc_busy;
+	unsigned int		pfc_cycles;
+	unsigned int		last_listen;
+	unsigned int		last_ofdm_errors;
+	unsigned int		last_cck_errors;
+	unsigned int		sum_ofdm_errors;
+	unsigned int		sum_cck_errors;
+};
+
+void ath5k_ani_init(struct ath5k_hw *ah, enum ath5k_ani_mode mode);
+void ath5k_ani_mib_intr(struct ath5k_hw *ah);
+void ath5k_ani_calibration(struct ath5k_hw *ah);
+void ath5k_ani_phy_error_report(struct ath5k_hw *ah,
+				enum ath5k_phy_error_code phyerr);
+
+/* for manual control */
+void ath5k_ani_set_noise_immunity_level(struct ath5k_hw *ah, int level);
+void ath5k_ani_set_spur_immunity_level(struct ath5k_hw *ah, int level);
+void ath5k_ani_set_firstep_level(struct ath5k_hw *ah, int level);
+void ath5k_ani_set_ofdm_weak_signal_detection(struct ath5k_hw *ah, bool on);
+void ath5k_ani_set_cck_weak_signal_detection(struct ath5k_hw *ah, bool on);
+
+void ath5k_ani_print_counters(struct ath5k_hw *ah);
+
+#endif /* ANI_H */