b43: implement PPR (Power Per Rate) management/API

Broadcom hardware supports auto-adjustment of TX power depending on the
currently used rate. So far all calculations were handled without any
helpers (API) using big arrays and magic offsets.
It seems Broadcom recently decided to clean this up by developing PPR.
Their wlc_ppr.h can be found in open parts of the SDK.
As we plan to implement support for rate-based TX power it makes sense
to also implement our version of PPR as well.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/b43/Makefile

@@ -18,6 +18,7 @@ b43-y				+= xmit.o
 b43-y				+= dma.o
 b43-y				+= pio.o
 b43-y				+= rfkill.o
+b43-y				+= ppr.o
 b43-$(CONFIG_B43_LEDS)		+= leds.o
 b43-$(CONFIG_B43_PCMCIA)	+= pcmcia.o
 b43-$(CONFIG_B43_SDIO)		+= sdio.o

drivers/net/wireless/b43/b43.h

@@ -791,6 +791,13 @@ struct b43_firmware {
 	bool pcm_request_failed;
 };
 
+enum b43_band {
+	B43_BAND_2G = 0,
+	B43_BAND_5G_LO = 1,
+	B43_BAND_5G_MI = 2,
+	B43_BAND_5G_HI = 3,
+};
+
 /* Device (802.11 core) initialization status. */
 enum {
 	B43_STAT_UNINIT = 0,	/* Uninitialized. */

drivers/net/wireless/b43/ppr.c

+/*
+ * Broadcom B43 wireless driver
+ * PPR (Power Per Rate) management
+ *
+ * Copyright (c) 2014 Rafał Miłecki <zajec5@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "ppr.h"
+#include "b43.h"
+
+#define ppr_for_each_entry(ppr, i, entry)				\
+	for (i = 0, entry = &(ppr)->__all_rates[i];			\
+	     i < B43_PPR_RATES_NUM;					\
+	     i++, entry++)
+
+void b43_ppr_clear(struct b43_wldev *dev, struct b43_ppr *ppr)
+{
+	memset(ppr, 0, sizeof(*ppr));
+
+	/* Compile-time PPR check */
+	BUILD_BUG_ON(sizeof(struct b43_ppr) != B43_PPR_RATES_NUM * sizeof(u8));
+}
+
+void b43_ppr_add(struct b43_wldev *dev, struct b43_ppr *ppr, int diff)
+{
+	int i;
+	u8 *rate;
+
+	ppr_for_each_entry(ppr, i, rate) {
+		*rate = clamp_val(*rate + diff, 0, 127);
+	}
+}
+
+void b43_ppr_apply_max(struct b43_wldev *dev, struct b43_ppr *ppr, u8 max)
+{
+	int i;
+	u8 *rate;
+
+	ppr_for_each_entry(ppr, i, rate) {
+		*rate = min(*rate, max);
+	}
+}
+
+void b43_ppr_apply_min(struct b43_wldev *dev, struct b43_ppr *ppr, u8 min)
+{
+	int i;
+	u8 *rate;
+
+	ppr_for_each_entry(ppr, i, rate) {
+		*rate = max(*rate, min);
+	}
+}
+
+u8 b43_ppr_get_max(struct b43_wldev *dev, struct b43_ppr *ppr)
+{
+	u8 res = 0;
+	int i;
+	u8 *rate;
+
+	ppr_for_each_entry(ppr, i, rate) {
+		res = max(*rate, res);
+	}
+
+	return res;
+}
+
+bool b43_ppr_load_max_from_sprom(struct b43_wldev *dev, struct b43_ppr *ppr,
+				 enum b43_band band)
+{
+	struct b43_ppr_rates *rates = &ppr->rates;
+	struct ssb_sprom *sprom = dev->dev->bus_sprom;
+	struct b43_phy *phy = &dev->phy;
+	u8 maxpwr, off;
+	u32 sprom_ofdm_po;
+	u16 *sprom_mcs_po;
+	u8 extra_cdd_po, extra_stbc_po;
+	int i;
+
+	switch (band) {
+	case B43_BAND_2G:
+		maxpwr = min(sprom->core_pwr_info[0].maxpwr_2g,
+			     sprom->core_pwr_info[1].maxpwr_2g);
+		sprom_ofdm_po = sprom->ofdm2gpo;
+		sprom_mcs_po = sprom->mcs2gpo;
+		extra_cdd_po = (sprom->cddpo >> 0) & 0xf;
+		extra_stbc_po = (sprom->stbcpo >> 0) & 0xf;
+		break;
+	case B43_BAND_5G_LO:
+		maxpwr = min(sprom->core_pwr_info[0].maxpwr_5gl,
+			     sprom->core_pwr_info[1].maxpwr_5gl);
+		sprom_ofdm_po = sprom->ofdm5glpo;
+		sprom_mcs_po = sprom->mcs5glpo;
+		extra_cdd_po = (sprom->cddpo >> 8) & 0xf;
+		extra_stbc_po = (sprom->stbcpo >> 8) & 0xf;
+		break;
+	case B43_BAND_5G_MI:
+		maxpwr = min(sprom->core_pwr_info[0].maxpwr_5g,
+			     sprom->core_pwr_info[1].maxpwr_5g);
+		sprom_ofdm_po = sprom->ofdm5gpo;
+		sprom_mcs_po = sprom->mcs5gpo;
+		extra_cdd_po = (sprom->cddpo >> 4) & 0xf;
+		extra_stbc_po = (sprom->stbcpo >> 4) & 0xf;
+		break;
+	case B43_BAND_5G_HI:
+		maxpwr = min(sprom->core_pwr_info[0].maxpwr_5gh,
+			     sprom->core_pwr_info[1].maxpwr_5gh);
+		sprom_ofdm_po = sprom->ofdm5ghpo;
+		sprom_mcs_po = sprom->mcs5ghpo;
+		extra_cdd_po = (sprom->cddpo >> 12) & 0xf;
+		extra_stbc_po = (sprom->stbcpo >> 12) & 0xf;
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		return false;
+	}
+
+	if (band == B43_BAND_2G) {
+		for (i = 0; i < 4; i++) {
+			off = ((sprom->cck2gpo >> (i * 4)) & 0xf) * 2;
+			rates->cck[i] = maxpwr - off;
+		}
+	}
+
+	/* OFDM */
+	for (i = 0; i < 8; i++) {
+		off = ((sprom_ofdm_po >> (i * 4)) & 0xf) * 2;
+		rates->ofdm[i] = maxpwr - off;
+	}
+
+	/* MCS 20 SISO */
+	rates->mcs_20[0] = rates->ofdm[0];
+	rates->mcs_20[1] = rates->ofdm[2];
+	rates->mcs_20[2] = rates->ofdm[3];
+	rates->mcs_20[3] = rates->ofdm[4];
+	rates->mcs_20[4] = rates->ofdm[5];
+	rates->mcs_20[5] = rates->ofdm[6];
+	rates->mcs_20[6] = rates->ofdm[7];
+	rates->mcs_20[7] = rates->ofdm[7];
+
+	/* MCS 20 CDD */
+	for (i = 0; i < 4; i++) {
+		off = ((sprom_mcs_po[0] >> (i * 4)) & 0xf) * 2;
+		rates->mcs_20_cdd[i] = maxpwr - off;
+		if (phy->type == B43_PHYTYPE_N && phy->rev >= 3)
+			rates->mcs_20_cdd[i] -= extra_cdd_po;
+	}
+	for (i = 0; i < 4; i++) {
+		off = ((sprom_mcs_po[1] >> (i * 4)) & 0xf) * 2;
+		rates->mcs_20_cdd[4 + i] = maxpwr - off;
+		if (phy->type == B43_PHYTYPE_N && phy->rev >= 3)
+			rates->mcs_20_cdd[4 + i] -= extra_cdd_po;
+	}
+
+	/* OFDM 20 CDD */
+	rates->ofdm_20_cdd[0] = rates->mcs_20_cdd[0];
+	rates->ofdm_20_cdd[1] = rates->mcs_20_cdd[0];
+	rates->ofdm_20_cdd[2] = rates->mcs_20_cdd[1];
+	rates->ofdm_20_cdd[3] = rates->mcs_20_cdd[2];
+	rates->ofdm_20_cdd[4] = rates->mcs_20_cdd[3];
+	rates->ofdm_20_cdd[5] = rates->mcs_20_cdd[4];
+	rates->ofdm_20_cdd[6] = rates->mcs_20_cdd[5];
+	rates->ofdm_20_cdd[7] = rates->mcs_20_cdd[6];
+
+	/* MCS 20 STBC */
+	for (i = 0; i < 4; i++) {
+		off = ((sprom_mcs_po[0] >> (i * 4)) & 0xf) * 2;
+		rates->mcs_20_stbc[i] = maxpwr - off;
+		if (phy->type == B43_PHYTYPE_N && phy->rev >= 3)
+			rates->mcs_20_stbc[i] -= extra_stbc_po;
+	}
+	for (i = 0; i < 4; i++) {
+		off = ((sprom_mcs_po[1] >> (i * 4)) & 0xf) * 2;
+		rates->mcs_20_stbc[4 + i] = maxpwr - off;
+		if (phy->type == B43_PHYTYPE_N && phy->rev >= 3)
+			rates->mcs_20_stbc[4 + i] -= extra_stbc_po;
+	}
+
+	/* MCS 20 SDM */
+	for (i = 0; i < 4; i++) {
+		off = ((sprom_mcs_po[2] >> (i * 4)) & 0xf) * 2;
+		rates->mcs_20_sdm[i] = maxpwr - off;
+	}
+	for (i = 0; i < 4; i++) {
+		off = ((sprom_mcs_po[3] >> (i * 4)) & 0xf) * 2;
+		rates->mcs_20_sdm[4 + i] = maxpwr - off;
+	}
+
+	return true;
+}

drivers/net/wireless/b43/ppr.h

+#ifndef LINUX_B43_PPR_H_
+#define LINUX_B43_PPR_H_
+
+#include <linux/types.h>
+
+#define B43_PPR_CCK_RATES_NUM		4
+#define B43_PPR_OFDM_RATES_NUM		8
+#define B43_PPR_MCS_RATES_NUM		8
+
+#define B43_PPR_RATES_NUM	(B43_PPR_CCK_RATES_NUM +	\
+				 B43_PPR_OFDM_RATES_NUM * 2 +	\
+				 B43_PPR_MCS_RATES_NUM * 4)
+
+struct b43_ppr_rates {
+	u8 cck[B43_PPR_CCK_RATES_NUM];
+	u8 ofdm[B43_PPR_OFDM_RATES_NUM];
+	u8 ofdm_20_cdd[B43_PPR_OFDM_RATES_NUM];
+	u8 mcs_20[B43_PPR_MCS_RATES_NUM]; /* SISO */
+	u8 mcs_20_cdd[B43_PPR_MCS_RATES_NUM];
+	u8 mcs_20_stbc[B43_PPR_MCS_RATES_NUM];
+	u8 mcs_20_sdm[B43_PPR_MCS_RATES_NUM];
+};
+
+struct b43_ppr {
+	/* All powers are in qdbm (Q5.2) */
+	union {
+		u8 __all_rates[B43_PPR_RATES_NUM];
+		struct b43_ppr_rates rates;
+	};
+};
+
+struct b43_wldev;
+enum b43_band;
+
+void b43_ppr_clear(struct b43_wldev *dev, struct b43_ppr *ppr);
+
+void b43_ppr_add(struct b43_wldev *dev, struct b43_ppr *ppr, int diff);
+void b43_ppr_apply_max(struct b43_wldev *dev, struct b43_ppr *ppr, u8 max);
+void b43_ppr_apply_min(struct b43_wldev *dev, struct b43_ppr *ppr, u8 min);
+u8 b43_ppr_get_max(struct b43_wldev *dev, struct b43_ppr *ppr);
+
+bool b43_ppr_load_max_from_sprom(struct b43_wldev *dev, struct b43_ppr *ppr,
+				 enum b43_band band);
+
+#endif /* LINUX_B43_PPR_H_ */