[PATCH wireless-next v2 1/5] b43: N-PHY: fix the TX tone sample table

[Luca Casati <luk00casati@gmail.com>]

b43_nphy_load_samples() masked with (0x3FF << 10) instead of shifting
the masked I value, and b43_nphy_gen_load_samples() fed
cordic_calc_iq() a 16.16 fixed-point angle (CORDIC_FIXED() of a value
already shifted by 16) held in a u16, while the function takes whole
degrees. Together the sample table ended up all zeros, so every
calibration that plays a test tone (TX IQ/LO, RX IQ) ran without a
signal.

Compute the rotation in whole degrees as brcmsmac does and fix the
precedence.

Tested on a BCM43228 (N-PHY rev 16, radio 2057 rev 9).

mmiotraces: https://github.com/Luca00casati/b43patch/blob/755c2d8/traces/excerpts/patch1-tone-table.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 | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/broadcom/b43/phy_n.c b/drivers/net/wireless/broadcom/b43/phy_n.c
index bbc30cbad..c4e6c1ac0 100644
--- a/drivers/net/wireless/broadcom/b43/phy_n.c
+++ b/drivers/net/wireless/broadcom/b43/phy_n.c
@@ -1515,7 +1515,7 @@ static int b43_nphy_load_samples(struct b43_wldev *dev,
 		b43_nphy_stay_in_carrier_search(dev, 1);
 
 	for (i = 0; i < len; i++) {
-		data[i] = (samples[i].i & 0x3FF << 10);
+		data[i] = (samples[i].i & 0x3FF) << 10;
 		data[i] |= samples[i].q & 0x3FF;
 	}
 	b43_ntab_write_bulk(dev, B43_NTAB32(17, 0), len, data);
@@ -1531,7 +1531,8 @@ static u16 b43_nphy_gen_load_samples(struct b43_wldev *dev, u32 freq, u16 max,
 					bool test)
 {
 	int i;
-	u16 bw, len, rot, angle;
+	u16 bw, len;
+	s32 rot, angle;
 	struct cordic_iq *samples;
 
 	bw = b43_is_40mhz(dev) ? 40 : 20;
@@ -1554,11 +1555,11 @@ static u16 b43_nphy_gen_load_samples(struct b43_wldev *dev, u32 freq, u16 max,
 		b43err(dev->wl, "allocation for samples generation failed\n");
 		return 0;
 	}
-	rot = (((freq * 36) / bw) << 16) / 100;
+	rot = ((freq * 36) / bw) / 100;
 	angle = 0;
 
 	for (i = 0; i < len; i++) {
-		samples[i] = cordic_calc_iq(CORDIC_FIXED(angle));
+		samples[i] = cordic_calc_iq(angle);
 		angle += rot;
 		samples[i].q = CORDIC_FLOAT(samples[i].q * max);
 		samples[i].i = CORDIC_FLOAT(samples[i].i * max);
-- 
2.43.0