[PATCH wireless-next v2 2/5] b43: N-PHY: fix TX IQ/LO calibration

[Luca Casati <luk00casati@gmail.com>]

Several bugs kept the TX IQ/LO calibration from working, and on rev7+
it left TX dead afterwards:

- The busy poll on IQLOCAL_CMD was inverted: bits 15:14 are set while a
  step runs, so it stopped waiting as soon as the step started.
- The final copy was reversed: it wrote the stale buffer over the best
  coefficients (table 15 at 96) and read the active ones (at 80), so the
  result was never applied.
- TxCalPhyCleanup lacked the rev7+ part of brcmsmac's
  wlc_phy_txcal_phycleanup_nphy(): the 0x80 and 0x8 (PA power-up) RF
  overrides set up for the cal were left in place.
- There was no counterpart to b43_nphy_tx_cal_radio_setup_rev7(), so the
  TSSI/IQ-cal path stayed switched in. Add one, following
  wlc_phy_txcal_radio_cleanup_nphy().
- The TRSW override for the second core used 8, which does not fit the
  2-bit field on rev7+; use 2 as wl does.

With these, on a BCM43228 (N-PHY rev 16, radio 2057 rev 9) the final
coefficients are close to the proprietary wl driver's, though not
equal.

mmiotraces: https://github.com/Luca00casati/b43patch/blob/755c2d8/traces/excerpts/patch2-iqlo-poll.txt
            https://github.com/Luca00casati/b43patch/blob/755c2d8/traces/excerpts/patch2-trsw.txt
            https://github.com/Luca00casati/b43patch/blob/755c2d8/traces/excerpts/patch2-coefficients.txt

Found and fixed with the help of an AI coding assistant (Claude Opus 5.5),
by comparing mmiotraces of b43 and wl on the same card.

Signed-off-by: Luca Casati <luk00casati@gmail.com>
---
 drivers/net/wireless/broadcom/b43/phy_n.c | 73 +++++++++++++++++++++--
 1 file changed, 68 insertions(+), 5 deletions(-)

diff --git a/drivers/net/wireless/broadcom/b43/phy_n.c b/drivers/net/wireless/broadcom/b43/phy_n.c
index c4e6c1ac0..6b0140f05 100644
--- a/drivers/net/wireless/broadcom/b43/phy_n.c
+++ b/drivers/net/wireless/broadcom/b43/phy_n.c
@@ -4775,6 +4775,32 @@ static void b43_nphy_tx_cal_radio_setup_rev7(struct b43_wldev *dev)
 	}
 }
 
+static void b43_nphy_tx_cal_radio_cleanup(struct b43_wldev *dev)
+{
+	struct b43_phy *phy = &dev->phy;
+	u16 *save = dev->phy.n->tx_rx_cal_radio_saveregs;
+	int core, off;
+	u16 r;
+
+	if (phy->rev < 7 || phy->rev >= 19)
+		return;
+
+	for (core = 0; core < 2; core++) {
+		r = core ? 0x20 : 0;
+		off = core * 11;
+
+		b43_radio_write(dev, r + R2057_TX0_TX_SSI_MASTER, save[off + 0]);
+		b43_radio_write(dev, r + R2057_TX0_IQCAL_VCM_HG, save[off + 1]);
+		b43_radio_write(dev, r + R2057_TX0_IQCAL_IDAC, save[off + 2]);
+		b43_radio_write(dev, r + R2057_TX0_TSSI_VCM, save[off + 3]);
+		b43_radio_write(dev, r + R2057_TX0_TX_SSI_MUX, save[off + 5]);
+		if (phy->radio_rev != 5)
+			b43_radio_write(dev, r + R2057_TX0_TSSIA, save[off + 6]);
+		b43_radio_write(dev, r + R2057_TX0_TSSIG, save[off + 7]);
+		b43_radio_write(dev, r + R2057_TX0_TSSI_MISC1, save[off + 8]);
+	}
+}
+
 /* https://bcm-v4.sipsolutions.net/802.11/PHY/N/TxCalRadioSetup */
 static void b43_nphy_tx_cal_radio_setup(struct b43_wldev *dev)
 {
@@ -5033,7 +5059,9 @@ static struct nphy_txgains b43_nphy_get_tx_gains(struct b43_wldev *dev)
 /* https://bcm-v4.sipsolutions.net/802.11/PHY/N/TxCalPhyCleanup */
 static void b43_nphy_tx_cal_phy_cleanup(struct b43_wldev *dev)
 {
-	u16 *regs = dev->phy.n->tx_rx_cal_phy_saveregs;
+	struct b43_phy *phy = &dev->phy;
+	struct b43_phy_n *nphy = dev->phy.n;
+	u16 *regs = nphy->tx_rx_cal_phy_saveregs;
 
 	if (dev->phy.rev >= 3) {
 		b43_phy_write(dev, B43_NPHY_AFECTL_C1, regs[0]);
@@ -5047,7 +5075,37 @@ static void b43_nphy_tx_cal_phy_cleanup(struct b43_wldev *dev)
 		b43_phy_write(dev, B43_NPHY_RFCTL_INTC2, regs[8]);
 		b43_phy_write(dev, B43_NPHY_PAPD_EN0, regs[9]);
 		b43_phy_write(dev, B43_NPHY_PAPD_EN1, regs[10]);
+
+		if (phy->rev >= 19)
+			b43_nphy_rf_ctl_override_rev19(dev, 0x80, 0, 0, true,
+						       1);
+		else if (phy->rev >= 7)
+			b43_nphy_rf_ctl_override_rev7(dev, 0x80, 0, 0, true, 1);
+
 		b43_nphy_reset_cca(dev);
+
+		if (nphy->use_int_tx_iq_lo_cal) {
+			if (phy->rev >= 19) {
+				b43_nphy_rf_ctl_override_rev19(dev, 0x8, 0, 0x3,
+							       true, 0);
+			} else if (phy->rev >= 8) {
+				b43_nphy_rf_ctl_override_rev7(dev, 0x8, 0, 0x3,
+							      true, 0);
+			} else if (phy->rev == 7) {
+				bool ghz2 = b43_current_band(dev->wl) ==
+					    NL80211_BAND_2GHZ;
+
+				b43_radio_maskset(dev, ghz2 ?
+						  R2057_PAD2G_TUNE_PUS_CORE0 :
+						  R2057_IPA5G_CASCOFFV_PU_CORE0,
+						  ~1, 1);
+				b43_radio_maskset(dev, ghz2 ?
+						  R2057_PAD2G_TUNE_PUS_CORE1 :
+						  R2057_IPA5G_CASCOFFV_PU_CORE1,
+						  ~1, 1);
+				b43_radio_mask(dev, R2057_OVR_REG0, ~(1 << 4));
+			}
+		}
 	} else {
 		b43_phy_maskset(dev, B43_NPHY_AFECTL_C1, 0x0FFF, regs[0]);
 		b43_phy_maskset(dev, B43_NPHY_AFECTL_C2, 0x0FFF, regs[1]);
@@ -5102,7 +5160,8 @@ static void b43_nphy_tx_cal_phy_setup(struct b43_wldev *dev)
 			b43_nphy_rf_ctl_intc_override(dev, N_INTC_OVERRIDE_PA,
 						      0, 3);
 		b43_nphy_rf_ctl_intc_override(dev, N_INTC_OVERRIDE_TRSW, 2, 1);
-		b43_nphy_rf_ctl_intc_override(dev, N_INTC_OVERRIDE_TRSW, 8, 2);
+		b43_nphy_rf_ctl_intc_override(dev, N_INTC_OVERRIDE_TRSW,
+					      phy->rev >= 7 ? 2 : 8, 2);
 
 		regs[9] = b43_phy_read(dev, B43_NPHY_PAPD_EN0);
 		regs[10] = b43_phy_read(dev, B43_NPHY_PAPD_EN1);
@@ -5480,10 +5539,13 @@ static int b43_nphy_cal_tx_iq_lo(struct b43_wldev *dev,
 			b43_phy_write(dev, B43_NPHY_IQLOCAL_CMD, cmd);
 			for (i = 0; i < 2000; i++) {
 				tmp = b43_phy_read(dev, B43_NPHY_IQLOCAL_CMD);
-				if (tmp & 0xC000)
+				if (!(tmp & 0xC000))
 					break;
 				udelay(10);
 			}
+			if (i == 2000)
+				b43err(dev->wl, "TX IQ/LO cal step 0x%04x timed out\n",
+				       cmd);
 
 			b43_ntab_read_bulk(dev, B43_NTAB16(15, 96), length,
 						buffer);
@@ -5500,8 +5562,8 @@ static int b43_nphy_cal_tx_iq_lo(struct b43_wldev *dev,
 		last = (dev->phy.rev < 3) ? 6 : 7;
 
 		if (!mphase || nphy->mphase_cal_phase_id == last) {
-			b43_ntab_write_bulk(dev, B43_NTAB16(15, 96), 4, buffer);
-			b43_ntab_read_bulk(dev, B43_NTAB16(15, 80), 4, buffer);
+			b43_ntab_read_bulk(dev, B43_NTAB16(15, 96), 4, buffer);
+			b43_ntab_write_bulk(dev, B43_NTAB16(15, 80), 4, buffer);
 			if (dev->phy.rev < 3) {
 				buffer[0] = 0;
 				buffer[1] = 0;
@@ -5540,6 +5602,7 @@ static int b43_nphy_cal_tx_iq_lo(struct b43_wldev *dev,
 
 	b43_nphy_tx_cal_phy_cleanup(dev);
 	b43_ntab_write_bulk(dev, B43_NTAB16(7, 0x110), 2, save);
+	b43_nphy_tx_cal_radio_cleanup(dev);
 
 	if (dev->phy.rev < 2 && (!mphase || nphy->mphase_cal_phase_id == last))
 		b43_nphy_tx_iq_workaround(dev);
-- 
2.43.0