b43: N-PHY: implement calculating RX IQ comp

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 99 insertions, 0 deletions

diff --git a/drivers/net/wireless/b43/phy_n.c b/drivers/net/wireless/b43/phy_n.c
index 776d0082ef1c..d08feffdce68 100644
--- a/drivers/net/wireless/b43/phy_n.c
+++ b/drivers/net/wireless/b43/phy_n.c
@@ -464,6 +464,105 @@ static void b43_nphy_rx_iq_coeffs(struct b43_wldev *dev, bool write,
         }
 }
 
+/* http://bcm-v4.sipsolutions.net/802.11/PHY/N/CalcRxIqComp */
+static void b43_nphy_calc_rx_iq_comp(struct b43_wldev *dev, u8 mask)
+{
+        int i;
+        s32 iq;
+        u32 ii;
+        u32 qq;
+        int iq_nbits, qq_nbits;
+        int arsh, brsh;
+        u16 tmp, a, b;
+
+        struct nphy_iq_est est;
+        struct b43_phy_n_iq_comp old;
+        struct b43_phy_n_iq_comp new = { };
+        bool error = false;
+
+        if (mask == 0)
+                return;
+
+        b43_nphy_rx_iq_coeffs(dev, false, &old);
+        b43_nphy_rx_iq_coeffs(dev, true, &new);
+        b43_nphy_rx_iq_est(dev, &est, 0x4000, 32, false);
+        new = old;
+
+        for (i = 0; i < 2; i++) {
+                if (i == 0 && (mask & 1)) {
+                        iq = est.iq0_prod;
+                        ii = est.i0_pwr;
+                        qq = est.q0_pwr;
+                } else if (i == 1 && (mask & 2)) {
+                        iq = est.iq1_prod;
+                        ii = est.i1_pwr;
+                        qq = est.q1_pwr;
+                } else {
+                        B43_WARN_ON(1);
+                        continue;
+                }
+
+                if (ii + qq < 2) {
+                        error = true;
+                        break;
+                }
+
+                iq_nbits = fls(abs(iq));
+                qq_nbits = fls(qq);
+
+                arsh = iq_nbits - 20;
+                if (arsh >= 0) {
+                        a = -((iq << (30 - iq_nbits)) + (ii >> (1 + arsh)));
+                        tmp = ii >> arsh;
+                } else {
+                        a = -((iq << (30 - iq_nbits)) + (ii << (-1 - arsh)));
+                        tmp = ii << -arsh;
+                }
+                if (tmp == 0) {
+                        error = true;
+                        break;
+                }
+                a /= tmp;
+
+                brsh = qq_nbits - 11;
+                if (brsh >= 0) {
+                        b = (qq << (31 - qq_nbits));
+                        tmp = ii >> brsh;
+                } else {
+                        b = (qq << (31 - qq_nbits));
+                        tmp = ii << -brsh;
+                }
+                if (tmp == 0) {
+                        error = true;
+                        break;
+                }
+                b = int_sqrt(b / tmp - a * a) - (1 << 10);
+
+                if (i == 0 && (mask & 0x1)) {
+                        if (dev->phy.rev >= 3) {
+                                new.a0 = a & 0x3FF;
+                                new.b0 = b & 0x3FF;
+                        } else {
+                                new.a0 = b & 0x3FF;
+                                new.b0 = a & 0x3FF;
+                        }
+                } else if (i == 1 && (mask & 0x2)) {
+                        if (dev->phy.rev >= 3) {
+                                new.a1 = a & 0x3FF;
+                                new.b1 = b & 0x3FF;
+                        } else {
+                                new.a1 = b & 0x3FF;
+                                new.b1 = a & 0x3FF;
+                        }
+                }
+        }
+
+        if (error)
+                new = old;
+
+        b43_nphy_rx_iq_coeffs(dev, true, &new);
+}
+
 /* http://bcm-v4.sipsolutions.net/802.11/PHY/N/TxIqWar */
 static void b43_nphy_tx_iq_workaround(struct b43_wldev *dev)
 {