From 7f863d56bb39cfe852f94465c5ecb2376a660e41 Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@openwrt.org>
Date: Sat, 29 Nov 2008 01:34:33 +0000
Subject: madwifi: improve automatic channel selection by taking idle airtime
 into account

SVN-Revision: 13420
---
 package/madwifi/patches/389-autochannel.patch | 119 ++++++++++++++++++++++++++
 1 file changed, 119 insertions(+)
 create mode 100644 package/madwifi/patches/389-autochannel.patch

(limited to 'package/madwifi/patches/389-autochannel.patch')

diff --git a/package/madwifi/patches/389-autochannel.patch b/package/madwifi/patches/389-autochannel.patch
new file mode 100644
index 0000000000..8e5a62dafc
--- /dev/null
+++ b/package/madwifi/patches/389-autochannel.patch
@@ -0,0 +1,119 @@
+--- a/ath/if_ath.c
++++ b/ath/if_ath.c
+@@ -384,6 +384,7 @@ static u_int32_t ath_get_real_maxtxpower
+ 
+ static void ath_poll_disable(struct net_device *dev);
+ static void ath_poll_enable(struct net_device *dev);
++static void ath_fetch_idle_time(struct ath_softc *sc);
+ 
+ /* calibrate every 30 secs in steady state but check every second at first. */
+ static int ath_calinterval = ATH_SHORT_CALINTERVAL;
+@@ -2579,6 +2580,7 @@ ath_init(struct net_device *dev)
+ 	 * be followed by initialization of the appropriate bits
+ 	 * and then setup of the interrupt mask.
+ 	 */
++	ath_fetch_idle_time(sc);
+ 	sc->sc_curchan.channel = ic->ic_curchan->ic_freq;
+ 	sc->sc_curchan.channelFlags = ath_chan2flags(ic->ic_curchan);
+ 	if (!ath_hal_reset(ah, sc->sc_opmode, &sc->sc_curchan, AH_FALSE, &status)) {
+@@ -2913,6 +2915,34 @@ ath_hw_check_atim(struct ath_softc *sc, 
+ }
+ 
+ 
++#define AR5K_RXCLEAR	0x80f4
++#define AR5K_CYCLES		0x80f8
++static void
++ath_fetch_idle_time(struct ath_softc *sc)
++{
++	struct ieee80211com *ic = &sc->sc_ic;
++	struct ath_hal *ah = sc->sc_ah;
++	u_int32_t cc, rx;
++	u_int32_t time = 0;
++
++	if (sc->sc_ah->ah_macType < 5212)
++		return;
++
++	rx = OS_REG_READ(ah, AR5K_RXCLEAR);
++	cc = OS_REG_READ(ah, AR5K_CYCLES);
++	if (rx > cc)
++		return; /* wraparound */
++
++	if (sc->sc_last_chan)
++		sc->sc_last_chan->ic_idletime = 100 * (cc - rx) / cc;
++	sc->sc_last_chan = ic->ic_curchan;
++
++	OS_REG_WRITE(ah, AR5K_RXCLEAR, 0);
++	OS_REG_WRITE(ah, AR5K_CYCLES, 0);
++}
++#undef AR5K_RXCLEAR
++#undef AR5K_CYCLES
++
+ /*
+  * Reset the hardware w/o losing operational state.  This is
+  * basically a more efficient way of doing ath_stop, ath_init,
+@@ -2939,6 +2969,7 @@ ath_reset(struct net_device *dev)
+ 	 * Convert to a HAL channel description with the flags
+ 	 * constrained to reflect the current operating mode.
+ 	 */
++	ath_fetch_idle_time(sc);
+ 	c = ic->ic_curchan;
+ 	sc->sc_curchan.channel = c->ic_freq;
+ 	sc->sc_curchan.channelFlags = ath_chan2flags(c);
+@@ -9019,6 +9050,7 @@ ath_chan_set(struct ath_softc *sc, struc
+ 	u_int8_t channel_change_required = 0;
+ 	struct timeval tv;
+ 
++	ath_fetch_idle_time(sc);
+ 	/*
+ 	 * Convert to a HAL channel description with
+ 	 * the flags constrained to reflect the current
+--- a/ath/if_athvar.h
++++ b/ath/if_athvar.h
+@@ -773,6 +773,7 @@ struct ath_softc {
+ 	struct ieee80211vap **sc_bslot;		/* beacon xmit slots */
+ 	int sc_bnext;				/* next slot for beacon xmit */
+ 
++	struct ieee80211_channel *sc_last_chan;
+ 	int sc_beacon_cal;			/* use beacon timer for calibration */
+ 	u_int64_t sc_lastcal;			/* last time the calibration was performed */
+ 	struct timer_list sc_cal_ch;		/* calibration timer */
+--- a/net80211/_ieee80211.h
++++ b/net80211/_ieee80211.h
+@@ -148,6 +148,7 @@ struct ieee80211_channel {
+ 	int8_t ic_maxpower;	/* maximum tx power in dBm */
+ 	int8_t ic_minpower;	/* minimum tx power in dBm */
+ 	u_int8_t ic_scanflags;
++	u_int8_t ic_idletime; /* phy idle time in % */
+ };
+ 
+ #define	IEEE80211_CHAN_MAX	255
+--- a/net80211/ieee80211_scan_ap.c
++++ b/net80211/ieee80211_scan_ap.c
+@@ -423,6 +423,19 @@ pc_cmp_rssi(struct ap_state *as, struct 
+ 
+ /* This function must be invoked with locks acquired */
+ static int
++pc_cmp_idletime(struct ieee80211_channel *a,
++		struct ieee80211_channel *b)
++{
++	if (!a->ic_idletime || !b->ic_idletime)
++		return 0;
++
++	/* a is better than b (return < 0) when a has more idle time than b */
++	return b->ic_idletime - a->ic_idletime;
++}
++
++
++/* This function must be invoked with locks acquired */
++static int
+ pc_cmp_samechan(struct ieee80211com *ic, struct ieee80211_channel *a,
+ 		struct ieee80211_channel *b)
+ {
+@@ -455,6 +468,7 @@ pc_cmp(const void *_a, const void *_b)
+ 		return res;					\
+ } while (0)
+ 
++	EVALUATE_CRITERION(idletime, a, b);
+ 	EVALUATE_CRITERION(radar, a, b);
+ 	EVALUATE_CRITERION(keepmode, params, a, b);
+ 	EVALUATE_CRITERION(sc, ic, a, b);
-- 
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