b43: update cordic code to match current specs

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Tested-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 21 insertions, 9 deletions

diff --git a/drivers/net/wireless/b43/phy_common.c b/drivers/net/wireless/b43/phy_common.c
index 446c41bb1e9f..8f7d7eff2d80 100644
--- a/drivers/net/wireless/b43/phy_common.c
+++ b/drivers/net/wireless/b43/phy_common.c
@@ -422,21 +422,28 @@ void b43_phyop_switch_analog_generic(struct b43_wldev *dev, bool on)
         b43_write16(dev, B43_MMIO_PHY0, on ? 0 : 0xF4);
 }
 
+/* http://bcm-v4.sipsolutions.net/802.11/PHY/Cordic */
 struct b43_c32 b43_cordic(int theta)
 {
         u32 arctg[] = { 2949120, 1740967, 919879, 466945, 234379, 117304,
                       58666, 29335, 14668, 7334, 3667, 1833, 917, 458,
                       229, 115, 57, 29, };
-        int i, tmp, signx = 1, angle = 0;
+        u8 i;
+        s32 tmp;
+        s8 signx = 1;
+        u32 angle = 0;
         struct b43_c32 ret = { .i = 39797, .q = 0, };
 
-        theta = clamp_t(int, theta, -180, 180);
+        while (theta > (180 << 16))
+                theta -= (360 << 16);
+        while (theta < -(180 << 16))
+                theta += (360 << 16);
 
-        if (theta > 90) {
-                theta -= 180;
+        if (theta > (90 << 16)) {
+                theta -= (180 << 16);
                 signx = -1;
-        } else if (theta < -90) {
-                theta += 180;
+        } else if (theta < -(90 << 16)) {
+                theta += (180 << 16);
                 signx = -1;
         }
 
diff --git a/drivers/net/wireless/b43/phy_common.h b/drivers/net/wireless/b43/phy_common.h
index 9e4de47d0608..bd480b481bfc 100644
--- a/drivers/net/wireless/b43/phy_common.h
+++ b/drivers/net/wireless/b43/phy_common.h
@@ -8,6 +8,10 @@ struct b43_wldev;
 /* Complex number using 2 32-bit signed integers */
 struct b43_c32 { s32 i, q; };
 
+#define CORDIC_CONVERT(value)   (((value) >= 0) ? \
+                                 ((((value) >> 15) + 1) >> 1) : \
+                                 -((((-(value)) >> 15) + 1) >> 1))
+
 /* PHY register routing bits */
 #define B43_PHYROUTE                    0x0C00 /* PHY register routing bits mask */
 #define  B43_PHYROUTE_BASE              0x0000 /* Base registers */
diff --git a/drivers/net/wireless/b43/phy_lp.c b/drivers/net/wireless/b43/phy_lp.c
index 453585073437..185219e0a552 100644
--- a/drivers/net/wireless/b43/phy_lp.c
+++ b/drivers/net/wireless/b43/phy_lp.c
@@ -1784,7 +1784,8 @@ static void lpphy_start_tx_tone(struct b43_wldev *dev, s32 freq, u16 max)
 {
         struct b43_phy_lp *lpphy = dev->phy.lp;
         u16 buf[64];
-        int i, samples = 0, angle = 0, rotation = (9 * freq) / 500;
+        int i, samples = 0, angle = 0;
+        int rotation = (((36 * freq) / 20) << 16) / 100;
         struct b43_c32 sample;
 
         lpphy->tx_tone_freq = freq;
@@ -1803,8 +1804,8 @@ static void lpphy_start_tx_tone(struct b43_wldev *dev, s32 freq, u16 max)
         for (i = 0; i < samples; i++) {
                 sample = b43_cordic(angle);
                 angle += rotation;
-                buf[i] = ((sample.i * max) & 0xFF) << 8;
-                buf[i] |= (sample.q * max) & 0xFF;
+                buf[i] = CORDIC_CONVERT((sample.i * max) & 0xFF) << 8;
+                buf[i] |= CORDIC_CONVERT((sample.q * max) & 0xFF);
         }
 
         b43_lptab_write_bulk(dev, B43_LPTAB16(5, 0), samples, buf);