From 6287af195257f486bc37d22c4e6a4619ac37c4f8 Mon Sep 17 00:00:00 2001
From: sephe <sephe>
Date: Wed, 7 Feb 2007 14:52:42 +0000
Subject: [PATCH] Convert RX desc's rssi field to relative RX signal strength
 (relative to noise floor).

The conversion for Maxim, Philips and GCT RF are adapted from Realtek's
818x Linux driver.
---
 sys/dev/netif/rtw/rtw.c       | 89 +++++++++++++++++++++++++++++++++++++------
 sys/dev/netif/rtw/rtwreg.h    |  5 ++-
 sys/dev/netif/rtw/rtwvar.h    | 10 +++--
 sys/dev/netif/rtw/sa2400reg.h | 17 ++++++++-
 4 files changed, 104 insertions(+), 17 deletions(-)

diff --git a/sys/dev/netif/rtw/rtw.c b/sys/dev/netif/rtw/rtw.c
index 21a74455ba..889a30c985 100644
--- a/sys/dev/netif/rtw/rtw.c
+++ b/sys/dev/netif/rtw/rtw.c
@@ -32,7 +32,7 @@
  * SUCH DAMAGE.
  *
  * $NetBSD: rtw.c,v 1.72 2006/03/28 00:48:10 dyoung Exp $
- * $DragonFly: src/sys/dev/netif/rtw/rtw.c,v 1.5 2006/12/22 23:26:21 swildner Exp $
+ * $DragonFly: src/sys/dev/netif/rtw/rtw.c,v 1.6 2007/02/07 14:52:42 sephe Exp $
  */
 
 /*
@@ -97,6 +97,7 @@
 #include "rtwphyio.h"
 #include "rtwphy.h"
 #include "smc93cx6var.h"
+#include "sa2400reg.h"
 
 /* XXX */
 #define IEEE80211_DUR_DS_LONG_PREAMBLE	144
@@ -261,6 +262,11 @@ static int	rtw_compute_duration(const struct ieee80211_frame_min *,
 				     struct rtw_duration *,
 				     struct rtw_duration *, int *, int);
 
+static int	rtw_get_rssi(struct rtw_softc *, uint8_t, uint8_t);
+static int	rtw_maxim_getrssi(uint8_t, uint8_t);
+static int	rtw_gct_getrssi(uint8_t, uint8_t);
+static int	rtw_philips_getrssi(uint8_t, uint8_t);
+
 #ifdef RTW_DEBUG
 static void
 rtw_print_regs(struct rtw_regs *regs, const char *dvname, const char *where)
@@ -1461,18 +1467,11 @@ rtw_intr_rx(struct rtw_softc *sc, uint16_t isr)
 			goto next;
 		}
 
-		if (sc->sc_rfchipid == RTW_RFCHIPID_PHILIPS) {
-			rssi = SHIFTOUT(hrssi, RTW_RXRSSI_RSSI);
-		} else {
-			rssi = SHIFTOUT(hrssi, RTW_RXRSSI_IMR_RSSI);
-			/* TBD find out each front-end's LNA gain in the
-			 * front-end's units
-			 */
-			if ((hrssi & RTW_RXRSSI_IMR_LNA) == 0)
-				rssi |= 0x80;
-		}
+		rssi = SHIFTOUT(hrssi, RTW_RXRSSI_RSSI);
 		sq = SHIFTOUT(hrssi, RTW_RXRSSI_SQ);
 
+		rssi = rtw_get_rssi(sc, rssi, sq);
+
 		/*
 		 * Note well: now we cannot recycle the rs_mbuf unless
 		 * we restore its original length.
@@ -3694,14 +3693,17 @@ rtw_rf_attach(struct rtw_softc *sc, enum rtw_rfchipid rfchipid, int digphy)
 	case RTW_RFCHIPID_GCT:
 		rf = rtw_grf5101_create(&sc->sc_regs, rf_write, 0);
 		sc->sc_pwrstate_cb = rtw_maxim_pwrstate;
+		sc->sc_getrssi = rtw_gct_getrssi;
 		break;
 	case RTW_RFCHIPID_MAXIM:
 		rf = rtw_max2820_create(&sc->sc_regs, rf_write, 0);
 		sc->sc_pwrstate_cb = rtw_maxim_pwrstate;
+		sc->sc_getrssi = rtw_maxim_getrssi;
 		break;
 	case RTW_RFCHIPID_PHILIPS:
 		rf = rtw_sa2400_create(&sc->sc_regs, rf_write, digphy);
 		sc->sc_pwrstate_cb = rtw_philips_pwrstate;
+		sc->sc_getrssi = rtw_philips_getrssi;
 		break;
 	case RTW_RFCHIPID_RFMD:
 		/* XXX RFMD has no RF constructor */
@@ -4445,3 +4447,68 @@ rtw_compute_duration(const struct ieee80211_frame_min *wh,
 	}
 	return rtw_compute_duration1(lastlen + hdrlen, ack, icflags, rate, dn);
 }
+
+static int
+rtw_get_rssi(struct rtw_softc *sc, uint8_t raw, uint8_t sq)
+{
+	int rssi;
+
+	rssi = sc->sc_getrssi(raw, sq);
+
+	if (rssi == 0)
+		rssi = 1;
+	else if (rssi > 100)
+		rssi = 100;
+
+	if (rssi > (RTW_NOISE_FLOOR + RTW_RSSI_CORR))
+		rssi -= (RTW_NOISE_FLOOR + RTW_RSSI_CORR);
+	else
+		rssi = 0;
+
+	return rssi;
+}
+
+static int
+rtw_maxim_getrssi(uint8_t raw, uint8_t sq __unused)
+{
+	int rssi = raw;
+
+	rssi &= 0x7e;
+	rssi >>= 1;
+	rssi += 0x42;
+	if (raw & 0x1)
+		rssi += 0xa;
+	rssi &= 0xff;
+
+	return rssi;
+}
+
+static int
+rtw_gct_getrssi(uint8_t raw, uint8_t sq __unused)
+{
+	int rssi = raw;
+
+	rssi &= 0x7e;
+	if ((raw & 0x1) == 0 || rssi > 0x3c)
+		rssi = 100;
+	else
+		rssi = (100 * rssi) / 0x3c;
+	rssi &= 0xff;
+
+	return rssi;
+}
+
+static int
+rtw_philips_getrssi(uint8_t raw, uint8_t sq)
+{
+	static const uint8_t sq_rssi_map[SA2400_SQ_RSSI_MAP_MAX] =
+	{ SA2400_SQ_RSSI_MAP };
+
+	if (sq < SA2400_SQ_RSSI_MAP_MAX - 1)	/* NB: -1 is intended */
+		return sq_rssi_map[sq];
+
+	if (sq == 0x80)
+		return 1;
+	else
+		return 0x32;
+}
diff --git a/sys/dev/netif/rtw/rtwreg.h b/sys/dev/netif/rtw/rtwreg.h
index eae59f405f..a39488fc5e 100644
--- a/sys/dev/netif/rtw/rtwreg.h
+++ b/sys/dev/netif/rtw/rtwreg.h
@@ -29,7 +29,7 @@
  * OF SUCH DAMAGE.
  *
  * $NetBSD: rtwreg.h,v 1.19 2006/03/10 23:37:35 dyoung Exp $
- * $DragonFly: src/sys/dev/netif/rtw/rtwreg.h,v 1.1 2006/09/03 07:37:58 sephe Exp $
+ * $DragonFly: src/sys/dev/netif/rtw/rtwreg.h,v 1.2 2007/02/07 14:52:42 sephe Exp $
  */
 
 /* RTL8180L Host Control and Status Registers */
@@ -1098,3 +1098,6 @@ struct rtw_rxdesc {
 #define RTW_BBP_CHSQLIM		0x1a	/* guess: channel signal-quality
 					 * threshold
 					 */
+
+#define RTW_NOISE_FLOOR		-95	/* guess */
+#define RTW_RSSI_CORR		131	/* Linux driver (256 - 125) */
diff --git a/sys/dev/netif/rtw/rtwvar.h b/sys/dev/netif/rtw/rtwvar.h
index 4ced154a0e..b74becb275 100644
--- a/sys/dev/netif/rtw/rtwvar.h
+++ b/sys/dev/netif/rtw/rtwvar.h
@@ -29,7 +29,7 @@
  * OF SUCH DAMAGE.
  *
  * $NetBSD: rtwvar.h,v 1.28 2006/02/16 20:17:16 perry Exp $
- * $DragonFly: src/sys/dev/netif/rtw/rtwvar.h,v 1.3 2006/12/22 23:26:21 swildner Exp $
+ * $DragonFly: src/sys/dev/netif/rtw/rtwvar.h,v 1.4 2007/02/07 14:52:42 sephe Exp $
  */
 
 #ifndef _DEV_IC_RTWVAR_H_
@@ -411,8 +411,6 @@ struct rtw_sa2400 {
 	int			sa_digphy;	/* 1: digital PHY */
 };
 
-typedef void (*rtw_pwrstate_t)(struct rtw_regs *, enum rtw_pwrstate, int, int);
-
 union rtw_keys {
 	uint8_t		rk_keys[4][16];
 	uint32_t	rk_words[16];
@@ -464,7 +462,11 @@ struct rtw_softc {
 
 	enum rtw_pwrstate	sc_pwrstate;
 
-	rtw_pwrstate_t		sc_pwrstate_cb;
+	void			(*sc_pwrstate_cb)
+				(struct rtw_regs *, enum rtw_pwrstate,
+				 int, int);
+
+	int			(*sc_getrssi)(uint8_t, uint8_t);
 
 	struct rtw_rf		*sc_rf;
 
diff --git a/sys/dev/netif/rtw/sa2400reg.h b/sys/dev/netif/rtw/sa2400reg.h
index 27074db1f2..758721034a 100644
--- a/sys/dev/netif/rtw/sa2400reg.h
+++ b/sys/dev/netif/rtw/sa2400reg.h
@@ -29,7 +29,7 @@
  * OF SUCH DAMAGE.
  *
  * $NetBSD: sa2400reg.h,v 1.6 2006/03/08 08:26:50 dyoung Exp $
- * $DragonFly: src/sys/dev/netif/rtw/sa2400reg.h,v 1.1 2006/09/03 07:37:58 sephe Exp $
+ * $DragonFly: src/sys/dev/netif/rtw/sa2400reg.h,v 1.2 2007/02/07 14:52:42 sephe Exp $
  */
 
 #ifndef _DEV_IC_SA2400REG_H_
@@ -266,4 +266,19 @@
 						 *        0 = highest
 						 *        frequencies
 						 */
+
+#define SA2400_SQ_RSSI_MAP				\
+	0x64, 0x64, 0x63, 0x62, 0x61, 0x60, 0x5f, 0x5e,	\
+	0x5d, 0x5c, 0x5b, 0x5a, 0x57, 0x54, 0x52, 0x50,	\
+	0x4e, 0x4c, 0x4a, 0x48, 0x46, 0x44, 0x41, 0x3f,	\
+	0x3c, 0x3a, 0x37, 0x36, 0x36, 0x1c, 0x1c, 0x1b,	\
+	0x1b, 0x1a, 0x1a, 0x19, 0x19, 0x18, 0x18, 0x17,	\
+	0x17, 0x16, 0x16, 0x15, 0x15, 0x14, 0x14, 0x13,	\
+	0x13, 0x12, 0x12, 0x11, 0x11, 0x10, 0x10, 0x0f,	\
+	0x0f, 0x0e, 0x0e, 0x0d, 0x0d, 0x0c, 0x0c, 0x0b,	\
+	0x0b, 0x0a, 0x0a, 0x09, 0x09, 0x08, 0x08, 0x07,	\
+	0x07, 0x06, 0x06, 0x05, 0x04, 0x03, 0x02, 0x00
+
+#define SA2400_SQ_RSSI_MAP_MAX	80
+
 #endif /* _DEV_IC_SA2400REG_H_ */
-- 
2.11.4.GIT