b43: Rewrite TX power adjustment

This patch rewrites the TX power recalculation algorithms to scale better
with changed enviromnent. If there's low
TX traffic, the power will be checked against the desired values
every 60 seconds.
If there is high TX traffic, the check is redone every 2 seconds. This improves
the reaction times a lot and confuses the rate control less.
It will also reduce the time it initially takes to tune to a new TX power
value. With the old algorithm it could take about 30 to 45 seconds to settle to
a new power value. This will happen in about two to four seconds now.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 120 insertions, 98 deletions

diff --git a/drivers/net/wireless/b43/phy_g.c b/drivers/net/wireless/b43/phy_g.c
index bb95c54cd43d..fce84896d34c 100644
--- a/drivers/net/wireless/b43/phy_g.c
+++ b/drivers/net/wireless/b43/phy_g.c
@@ -2659,6 +2659,7 @@ static int b43_gphy_op_allocate(struct b43_wldev *dev)
 	/* OFDM-table address caching. */
 	gphy->ofdmtab_addr_direction = B43_OFDMTAB_DIRECTION_UNKNOWN;
 
+	gphy->average_tssi = 0xFF;
 
 	lo = kzalloc(sizeof(*lo), GFP_KERNEL);
 	if (!lo) {
@@ -3011,113 +3012,20 @@ static void b43_put_attenuation_into_ranges(struct b43_wldev *dev,
 	*_bbatt = clamp_val(bbatt, bb_min, bb_max);
 }
 
-static void b43_gphy_op_xmitpower(struct b43_wldev *dev)
+static void b43_gphy_op_adjust_txpower(struct b43_wldev *dev)
 {
-	struct ssb_bus *bus = dev->dev->bus;
 	struct b43_phy *phy = &dev->phy;
 	struct b43_phy_g *gphy = phy->g;
-	u16 tmp;
-	s8 v0, v1, v2, v3;
-	s8 average;
-	int max_pwr;
-	int desired_pwr, estimated_pwr, pwr_adjust;
-	int rfatt_delta, bbatt_delta;
 	int rfatt, bbatt;
 	u8 tx_control;
 
-	if (gphy->cur_idle_tssi == 0)
-		return;
-	if ((bus->boardinfo.vendor == SSB_BOARDVENDOR_BCM) &&
-	    (bus->boardinfo.type == SSB_BOARD_BU4306))
-		return;
-
-	tmp = b43_shm_read16(dev, B43_SHM_SHARED, 0x0058);
-	v0 = (s8) (tmp & 0x00FF);
-	v1 = (s8) ((tmp & 0xFF00) >> 8);
-	tmp = b43_shm_read16(dev, B43_SHM_SHARED, 0x005A);
-	v2 = (s8) (tmp & 0x00FF);
-	v3 = (s8) ((tmp & 0xFF00) >> 8);
-	tmp = 0;
-
-	if (v0 == 0x7F || v1 == 0x7F || v2 == 0x7F
-	    || v3 == 0x7F) {
-		tmp = b43_shm_read16(dev, B43_SHM_SHARED, 0x0070);
-		v0 = (s8) (tmp & 0x00FF);
-		v1 = (s8) ((tmp & 0xFF00) >> 8);
-		tmp = b43_shm_read16(dev, B43_SHM_SHARED, 0x0072);
-		v2 = (s8) (tmp & 0x00FF);
-		v3 = (s8) ((tmp & 0xFF00) >> 8);
-		if (v0 == 0x7F || v1 == 0x7F || v2 == 0x7F
-		    || v3 == 0x7F)
-			return;
-		v0 = (v0 + 0x20) & 0x3F;
-		v1 = (v1 + 0x20) & 0x3F;
-		v2 = (v2 + 0x20) & 0x3F;
-		v3 = (v3 + 0x20) & 0x3F;
-		tmp = 1;
-	}
-	b43_shm_clear_tssi(dev);
-
-	average = (v0 + v1 + v2 + v3 + 2) / 4;
-
-	if (tmp && (b43_shm_read16(dev, B43_SHM_SHARED, 0x005E) & 0x8))
-		average -= 13;
-
-	estimated_pwr = b43_gphy_estimate_power_out(dev, average);
-
-	max_pwr = dev->dev->bus->sprom.maxpwr_bg;
-	if ((dev->dev->bus->sprom.boardflags_lo
-	    & B43_BFL_PACTRL) && (phy->type == B43_PHYTYPE_G))
-		max_pwr -= 0x3;
-	if (unlikely(max_pwr <= 0)) {
-		b43warn(dev->wl,
-			"Invalid max-TX-power value in SPROM.\n");
-		max_pwr = 60;	/* fake it */
-		dev->dev->bus->sprom.maxpwr_bg = max_pwr;
-	}
-
-	/*TODO:
-	   max_pwr = min(REG - dev->dev->bus->sprom.antennagain_bgphy - 0x6, max_pwr)
-	   where REG is the max power as per the regulatory domain
-	 */
-
-	/* Get desired power (in Q5.2) */
-	desired_pwr = INT_TO_Q52(phy->power_level);
-	/* And limit it. max_pwr already is Q5.2 */
-	desired_pwr = clamp_val(desired_pwr, 0, max_pwr);
-	if (b43_debug(dev, B43_DBG_XMITPOWER)) {
-		b43dbg(dev->wl,
-		       "Current TX power output: " Q52_FMT
-		       " dBm, " "Desired TX power output: "
-		       Q52_FMT " dBm\n", Q52_ARG(estimated_pwr),
-		       Q52_ARG(desired_pwr));
-	}
-
-	/* Calculate the adjustment delta. */
-	pwr_adjust = desired_pwr - estimated_pwr;
-
-	/* RF attenuation delta. */
-	rfatt_delta = ((pwr_adjust + 7) / 8);
-	/* Lower attenuation => Bigger power output. Negate it. */
-	rfatt_delta = -rfatt_delta;
-
-	/* Baseband attenuation delta. */
-	bbatt_delta = pwr_adjust / 2;
-	/* Lower attenuation => Bigger power output. Negate it. */
-	bbatt_delta = -bbatt_delta;
-	/* RF att affects power level 4 times as much as
-	 * Baseband attennuation. Subtract it. */
-	bbatt_delta -= 4 * rfatt_delta;
-
-	/* So do we finally need to adjust something? */
-	if ((rfatt_delta == 0) && (bbatt_delta == 0))
-		return;
+	spin_lock_irq(&dev->wl->irq_lock);
 
 	/* Calculate the new attenuation values. */
 	bbatt = gphy->bbatt.att;
-	bbatt += bbatt_delta;
+	bbatt += gphy->bbatt_delta;
 	rfatt = gphy->rfatt.att;
-	rfatt += rfatt_delta;
+	rfatt += gphy->rfatt_delta;
 
 	b43_put_attenuation_into_ranges(dev, &bbatt, &rfatt);
 	tx_control = gphy->tx_control;
@@ -3152,6 +3060,14 @@ static void b43_gphy_op_xmitpower(struct b43_wldev *dev)
 	gphy->rfatt.att = rfatt;
 	gphy->bbatt.att = bbatt;
 
+	/* We drop the lock early, so we can sleep during hardware
+	 * adjustment. Possible races with op_recalc_txpower are harmless,
+	 * as we will be called once again in case we raced. */
+	spin_unlock_irq(&dev->wl->irq_lock);
+
+	if (b43_debug(dev, B43_DBG_XMITPOWER))
+		b43dbg(dev->wl, "Adjusting TX power\n");
+
 	/* Adjust the hardware */
 	b43_phy_lock(dev);
 	b43_radio_lock(dev);
@@ -3161,6 +3077,111 @@ static void b43_gphy_op_xmitpower(struct b43_wldev *dev)
 	b43_phy_unlock(dev);
 }
 
+static enum b43_txpwr_result b43_gphy_op_recalc_txpower(struct b43_wldev *dev,
+							bool ignore_tssi)
+{
+	struct b43_phy *phy = &dev->phy;
+	struct b43_phy_g *gphy = phy->g;
+	unsigned int average_tssi;
+	int cck_result, ofdm_result;
+	int estimated_pwr, desired_pwr, pwr_adjust;
+	int rfatt_delta, bbatt_delta;
+	unsigned int max_pwr;
+
+	/* First get the average TSSI */
+	cck_result = b43_phy_shm_tssi_read(dev, B43_SHM_SH_TSSI_CCK);
+	ofdm_result = b43_phy_shm_tssi_read(dev, B43_SHM_SH_TSSI_OFDM_G);
+	if ((cck_result < 0) && (ofdm_result < 0)) {
+		/* No TSSI information available */
+		if (!ignore_tssi)
+			goto no_adjustment_needed;
+		cck_result = 0;
+		ofdm_result = 0;
+	}
+	if (cck_result < 0)
+		average_tssi = ofdm_result;
+	else if (ofdm_result < 0)
+		average_tssi = cck_result;
+	else
+		average_tssi = (cck_result + ofdm_result) / 2;
+	/* Merge the average with the stored value. */
+	if (likely(gphy->average_tssi != 0xFF))
+		average_tssi = (average_tssi + gphy->average_tssi) / 2;
+	gphy->average_tssi = average_tssi;
+	B43_WARN_ON(average_tssi >= B43_TSSI_MAX);
+
+	/* Estimate the TX power emission based on the TSSI */
+	estimated_pwr = b43_gphy_estimate_power_out(dev, average_tssi);
+
+	B43_WARN_ON(phy->type != B43_PHYTYPE_G);
+	max_pwr = dev->dev->bus->sprom.maxpwr_bg;
+	if (dev->dev->bus->sprom.boardflags_lo & B43_BFL_PACTRL)
+		max_pwr -= 3; /* minus 0.75 */
+	if (unlikely(max_pwr >= INT_TO_Q52(30/*dBm*/))) {
+		b43warn(dev->wl,
+			"Invalid max-TX-power value in SPROM.\n");
+		max_pwr = INT_TO_Q52(20); /* fake it */
+		dev->dev->bus->sprom.maxpwr_bg = max_pwr;
+	}
+
+	/* Get desired power (in Q5.2) */
+	if (phy->desired_txpower < 0)
+		desired_pwr = INT_TO_Q52(0);
+	else
+		desired_pwr = INT_TO_Q52(phy->desired_txpower);
+	/* And limit it. max_pwr already is Q5.2 */
+	desired_pwr = clamp_val(desired_pwr, 0, max_pwr);
+	if (b43_debug(dev, B43_DBG_XMITPOWER)) {
+		b43dbg(dev->wl,
+		       "[TX power]  current = " Q52_FMT
+		       " dBm,  desired = " Q52_FMT
+		       " dBm,  max = " Q52_FMT "\n",
+		       Q52_ARG(estimated_pwr),
+		       Q52_ARG(desired_pwr),
+		       Q52_ARG(max_pwr));
+	}
+
+	/* Calculate the adjustment delta. */
+	pwr_adjust = desired_pwr - estimated_pwr;
+	if (pwr_adjust == 0)
+		goto no_adjustment_needed;
+
+	/* RF attenuation delta. */
+	rfatt_delta = ((pwr_adjust + 7) / 8);
+	/* Lower attenuation => Bigger power output. Negate it. */
+	rfatt_delta = -rfatt_delta;
+
+	/* Baseband attenuation delta. */
+	bbatt_delta = pwr_adjust / 2;
+	/* Lower attenuation => Bigger power output. Negate it. */
+	bbatt_delta = -bbatt_delta;
+	/* RF att affects power level 4 times as much as
+	 * Baseband attennuation. Subtract it. */
+	bbatt_delta -= 4 * rfatt_delta;
+
+	if (b43_debug(dev, B43_DBG_XMITPOWER)) {
+		int dbm = pwr_adjust < 0 ? -pwr_adjust : pwr_adjust;
+		b43dbg(dev->wl,
+		       "[TX power deltas]  %s" Q52_FMT " dBm   =>   "
+		       "bbatt-delta = %d,  rfatt-delta = %d\n",
+		       (pwr_adjust < 0 ? "-" : ""), Q52_ARG(dbm),
+		       bbatt_delta, rfatt_delta);
+	}
+	/* So do we finally need to adjust something in hardware? */
+	if ((rfatt_delta == 0) && (bbatt_delta == 0))
+		goto no_adjustment_needed;
+
+	/* Save the deltas for later when we adjust the power. */
+	gphy->bbatt_delta = bbatt_delta;
+	gphy->rfatt_delta = rfatt_delta;
+
+	/* We need to adjust the TX power on the device. */
+	return B43_TXPWR_RES_NEED_ADJUST;
+
+no_adjustment_needed:
+	return B43_TXPWR_RES_DONE;
+}
+
 static void b43_gphy_op_pwork_15sec(struct b43_wldev *dev)
 {
 	struct b43_phy *phy = &dev->phy;
@@ -3223,7 +3244,8 @@ const struct b43_phy_operations b43_phyops_g = {
 	.get_default_chan	= b43_gphy_op_get_default_chan,
 	.set_rx_antenna		= b43_gphy_op_set_rx_antenna,
 	.interf_mitigation	= b43_gphy_op_interf_mitigation,
-	.xmitpower		= b43_gphy_op_xmitpower,
+	.recalc_txpower		= b43_gphy_op_recalc_txpower,
+	.adjust_txpower		= b43_gphy_op_adjust_txpower,
 	.pwork_15sec		= b43_gphy_op_pwork_15sec,
 	.pwork_60sec		= b43_gphy_op_pwork_60sec,
 };